AEROSOL-GENERATING ARTICLE WITH DUAL WRAPPERS

[0001] The present disclosure relates to an aerosol-generating article comprising a rod of aerosol-generating substrate and at least two wrappers.

[0002] Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco containing substrate, is heated rather than combusted are known in the art. In heated aerosol-generating articles, the aerosol is generated by heating the aerosol-generating substrate.

[0003] It is known to provide a heating element for heating an aerosol-generating substrate of an aerosol-generating article. The heating element may be provided in the article in the form of a susceptor element, which is capable of being heated when penetrated by a varying magnetic field. Alternatively or additionally, the heating element may be provided in an aerosol-generating device for generating an inhalable vapor. Such a device may heat the aerosol-generating substrate contained in the aerosol-generating article without burning the aerosol-generating substrate. The aerosol-generating article may have a rod shape configured for insertion of a portion of the aerosol-generating article into a device cavity of the aerosol-generating device. The aerosol-generating device may also comprise a heating element configured for insertion into the rod of aerosol-generating substrate. The heating element may be located in the device cavity. When the aerosol-generating substrate of the aerosol-generating article is received in the device cavity, the heating element may penetrate the aerosol-generating substrate, and be inserted into the aerosol-generating substrate to heat the aerosol-generating substrate from the inside.

[0004] Heatable aerosol-generating articles may comprise one or more wrappers, circumscribing at least part of the aerosol-generating article. The provision of one or more wrappers may secure the components of the aerosol-generating article together.

[0005] During use, the outer, peripheral portions of the aerosol-generating substrate further away from the heating element may receive less heat from the heating element than the portions of the aerosol-generating substrate which are closer to the heating element. This results in a temperature gradient which may encourage condensation and slurry to migrate to cooler portions of the aerosol-generating substrate such as the outer periphery of the substrate. As a result, the wrapper may become stained, humid or wet during use. Wetting of the wrapper may decrease the tensile strength of the wrapper which may cause the aerosol-generating article to break, particularly at the junction between components of the aerosol-generating article, inside the device cavity of the aerosol-generating device when extracting the aerosol-generating article after use.

[0006] It is also known to provide wrappers on aerosol-generating articles which have been printed with coatings such as a lip release lacquer or, for example, indicia or a distinctive colour on the surface of the wrapper to provide an aerosol-generating article with a more aesthetically appealing and distinctive appearance. However, it may be desired to provide only a part of the length of the wrapper, such as at the mouth end of the aerosol-generating article, with the coating, indicia or distinctive colour. However, this may increase the complexity of the manufacturing process if the coating, indicia or distinctive colour are only applied to part of the surface of the wrapper.

[0007] It would be desirable to provide a wrapper with increased wet tensile strength and dry tensile strength to increase the mechanical robustness of the aerosol-generating article, particularly after use, to reduce the risk of breakage while extracting the aerosol-generating article from the device cavity of the aerosol-generating device. Furthermore, it would be desirable to configure the wrapper such that coatings, indicia or distinctive colours can be more easily applied to different portions of the aerosol-generating article without requiring complex manufacturing techniques or modifications to existing manufacturing processes.

[0008] According to the present invention there is provided an aerosol-generating article. The aerosol-generating article may comprise a rod of aerosol-generating substrate. The aerosol-generating article may comprise a downstream section located downstream of the rod of aerosol-generating substrate. The downstream section may comprise one or more hollow tubular elements. The aerosol-generating article may comprise at least two wrappers. The at least two wrappers may comprise a first wrapper and a second wrapper. Each of the first wrapper and the second wrapper may circumscribe at least one of the rod of aerosol-generating substrate and the downstream section. Each of the first wrapper and the second wrapper may have a bulk of less than or equal to 1.42 cubic centimetres per gram.

[0009] According to the present invention there is provided an aerosol-generating article. The aerosol-generating article comprises a rod of aerosol-generating substrate. The aerosol-generating article comprises a downstream section located downstream of the rod of aerosol-generating substrate. The downstream section comprises one or more hollow tubular elements. The aerosol-generating article comprises at least two wrappers. The at least two wrappers comprise a first wrapper and a second wrapper. Each of the first wrapper and the second wrapper circumscribe at least one of the rod of aerosol-generating substrate and the downstream section. Each of the first wrapper and the second wrapper have a bulk of less than or equal to 1.42 cubic centimetres per gram.

[0010] Advantageously, providing an aerosol-generating article comprising at least two wrappers allows different properties to be provided for each of the at least two wrappers. For example, one of the at least two wrappers could be provided with one or more of coatings, indicia or distinctive colours printed on the surface, and another of the at least two wrappers could be provided without coatings, indicia or distinctive colours. Alternatively, for example, one of the at least two wrappers could be provided with one or more of coatings, indicia or distinctive colours printed on the surface, and another of the at least two wrappers could be provided with a different selection of one or more of coatings, indicia or distinctive colours. Advantageously, the ability to provide different properties for each of the at least two wrappers may improve the versatility with which the article can be configured, when compared to the articles comprising a single wrapper. Advantageously, the ability to easily provide different properties to each of the at least two wrappers may improve the versatility with which the article can be configured without increasing the complexity of manufacturing of the article and without requiring modifications to existing manufacturing processes. This may also reduce manufacturing costs. For example, existing manufacturing techniques can be used to provide each of the at least two wrappers with different properties, and then the at least two wrappers may be combined in different configurations relative to each other to arrive at the desired distribution of properties.

[0011] Advantageously, providing a first wrapper and a second wrapper each having a bulk of less than or equal to 1.42 cubic centimetres per gram provides a desired tensile strength of each of the first wrapper and the second wrapper in both dry conditions (the dry tensile strength) and wet conditions (the wet tensile strength).

[0012] For example, it has been surprisingly found that decreasing the bulk of a wrapper from 1.44 (the bulk value for typical wrappers) to 1.13 resulted in a 75 percent increase in the dry tensile strength of the wrapper (when measured in accordance with ISO Standard 1924-2:2008). The wrapper was conditioned for at least 24 hours at 22±2 degrees Celsius and 60±5% relative humidity before testing.

[0013] Furthermore, it has been surprisingly found that decreasing the bulk of a wrapper from 1.44 to 1.13 results in approximately a 20 to 40 percent increase in the vertical force required to break an aerosol-generating article (lying horizontally) at junctions between components of the aerosol-generating article wrapped by the wrapper both before use and after 1 minute of use of the aerosol-generating article.

[0014] For example, it was found that, before use of an aerosol-generating article, the vertical force required to break the horizontally lying aerosol-generating article at the junction between two hollow tubular elements wrapped by a wrapper with a bulk of 1.13 was about 27 percent higher than for an aerosol-generating article differing only in the provision of a wrapper with a higher bulk of 1.44. Furthermore, after 1 minute of use of an aerosol-generating article, the vertical force required to break the horizontally lying aerosol-generating article at the junction between two tubular hollow tubular elements wrapped by a wrapper with a bulk of 1.13 was about 20 percent higher than for an aerosol-generating article differing only in the provision of a wrapper with a higher bulk of 1.44.

[0015] As a further example, it was found that, before use of an aerosol-generating article, the vertical force required to break the horizontally lying aerosol-generating article at the junction between a rod of aerosol-generating substrate and an element immediately upstream of the rod of aerosol-generating substrate wrapped by a wrapper with a bulk of 1.13 was about 27 percent higher than for an aerosol-generating article differing only in the provision of a wrapper with a higher bulk of 1.44. Furthermore, after 1 minute of use of an aerosol-generating article, the vertical force required to break the horizontally lying aerosol-generating article at the junction between a rod of aerosol-generating substrate and an element immediately upstream of the rod of aerosol-generating substrate wrapped by a wrapper with a bulk of 1.13 was about 40 percent higher than for an aerosol-generating article differing only in the provision of a wrapper with a higher bulk of 1.44.

[0016] Advantageously, providing a first wrapper and a second wrapper with improved tensile strength reduces the risk of breakage of the aerosol-generating article, particularly at the junctions between components, when extracting the aerosol-generating article from a device after use.

[0017] As used herein, the term ‘aerosol-generating substrate’ denotes a substrate capable of releasing volatile compounds upon heating, which can condense to form an aerosol.

[0018] As used herein, the term “aerosol” denotes a dispersion of solid particles, or liquid droplets, or a combination of solid particles and liquid droplets, in a gas. The aerosol may be visible or invisible. The aerosol may include vapours of substances that are ordinarily liquid or solid at room temperature as well as solid particles, or liquid droplets, or a combination of solid particles and liquid droplets.

[0019] As used herein, the term “aerosol-generating article” denotes an article comprising an aerosol-generating substrate that is capable of releasing volatile compounds that can form an aerosol. An aerosol-generating article may be disposable.

[0020] As used herein, the terms ‘upstream’, ‘downstream’, proximal’ and ‘distal’ are used to describe the relative positions of elements, or portions of elements, of aerosol-generating articles, aerosol-generating devices and aerosol-generating systems according to the disclosure. Aerosol-generating articles as described herein comprise a proximal end through which, in use, an aerosol exits the aerosol-generating article. The proximal end may also be referred to as the mouth end. In use, a user draws on the proximal end or mouth end of the aerosol-generating article in order to inhale an aerosol generated by the aerosol-generating article. The aerosol-generating article comprises a distal end opposite the proximal end or mouth end. The proximal end or mouth end of the aerosol-generating article may also be referred to as the downstream end. The distal end of the aerosol-generating article may also be referred to as the upstream end. Components, or portions of components, of the aerosol-generating article may be described as being upstream or downstream of one another based on their relative positions between the proximal or downstream end and the distal or upstream end of the aerosol-generating article.

[0021] As used herein the term ‘longitudinal’ is used to describe the direction between the downstream end or proximal end and the opposed upstream end or distal end of aerosol-generating articles, aerosol-generating devices and aerosol-generating systems according to the invention.

[0022] As used herein, the term ‘length’ is used to describe the maximum dimension of elements, or portions of elements, of aerosol-generating articles, aerosol-generating devices and aerosol-generating systems according to the disclosure in the longitudinal direction or along a longitudinal axis.

[0023] As used herein, the term ‘transverse’ is used to describe the direction perpendicular to the longitudinal direction.

[0024] As used herein, the term ‘width’ is used to describe the maximum transverse dimension of elements, or portions of elements, of aerosol-generating articles, aerosol-generating devices and aerosol-generating systems according to the disclosure. For the avoidance of doubt, as used herein the term ‘diameter’ may also be used to refer to the ‘width’ of elements, or portions of elements, of aerosol-generating articles, aerosol-generating devices and aerosol-generating systems according to the disclosure, which have a circular transverse cross-section.

[0025] Unless otherwise stated, references to the “cross-section” of the aerosol-generating article or a component of the aerosol-generating article refer to the transverse cross-section, perpendicular to the longitudinal direction or axis.

[0026] As used herein, the term “hollow tubular element” is used to denote a generally elongate element defining a lumen or airflow passage along a longitudinal axis thereof. In particular, the term “tubular” will be used in the following with reference to a tubular element having a substantially cylindrical cross-section and defining at least one airflow conduit establishing an uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it will be understood that alternative geometries (for example, alternative cross-sectional shapes) of the tubular element may be possible.

[0027] As used herein, the term “bulk” is defined as the inverse or reciprocal of density. In particular, for a wrapper, bulk is calculated by dividing the thickness of the wrapper by the grammage of the wrapper.

[0028] As used herein, the terms “grammage” or “basis weight” are equivalent, and are defined as equal to the mass per unit area of, for example, a wrapper. The grammage may be determined in accordance with ISO Standard 536:2012.

[0029] As used herein, the term “thickness” is used to describe the smallest dimension of, for example, a wrapper. The thickness is measured perpendicular to the length and width of the wrapper. The thickness may be determined in accordance with ISO Standard 534:2012.

[0030] Unless stated otherwise, measurements performed on a wrapper described herein are performed at 23 degrees Celsius and at a relative humidity of 50 percent.

[0031] The at least two wrappers of the aerosol-generating article comprise a first wrapper and a second wrapper.

[0032] The first wrapper may have a bulk of greater than or equal to 0.75 cubic centimetres per gram, greater than or equal to 0.80 cubic centimetres per gram, greater than or equal to 0.85 cubic centimetres per gram, greater than or equal to 0.90 cubic centimetres per gram, greater than or equal to 0.93 cubic centimetres per gram, or greater than or equal to 0.96 cubic centimetres per gram, or greater than or equal to 1.10 cubic centimetres per gram.

[0033] The second wrapper may have a bulk of greater than or equal to 0.75 cubic centimetres per gram, greater than or equal to 0.80 cubic centimetres per gram, greater than or equal to 0.85 cubic centimetres per gram, greater than or equal to 0.90 cubic centimetres per gram, greater than or equal to 0.93 cubic centimetres per gram, greater than or equal to 0.96 cubic centimetres per gram, or greater than or equal to 1.10 cubic centimetres per gram.

[0034] The first wrapper may have a bulk of less than or equal to 1.38 cubic centimetres per gram, less than or equal to 1.37 cubic centimetres per gram, less than or equal to 1.30 cubic centimetres per gram, or less than or equal to 1.23 cubic centimetres per gram.

[0035] The second wrapper may have a bulk of less than or equal to 1.38 cubic centimetres per gram, less than or equal to 1.37 cubic centimetres per gram, less than or equal to 1.30 cubic centimetres per gram, or less than or equal to 1.23 cubic centimetres per gram.

[0036] The first wrapper may have a bulk of between 0.75 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 1.10 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.75 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 1.10 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.75 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 1.10 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.75 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 1.10 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.75 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.23 cubic centimetres per gram, or between 1.10 cubic centimetres per gram and 1.23 cubic centimetres per gram.

[0037] The second wrapper may have a bulk of between 0.75 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 1.10 cubic centimetres per gram and 1.42 cubic centimetres per gram, between 0.75 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 1.10 cubic centimetres per gram and 1.38 cubic centimetres per gram, between 0.75 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 1.10 cubic centimetres per gram and 1.37 cubic centimetres per gram, between 0.75 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 1.10 cubic centimetres per gram and 1.30 cubic centimetres per gram, between 0.75 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.80 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.85 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.90 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.93 cubic centimetres per gram and 1.23 cubic centimetres per gram, between 0.96 cubic centimetres per gram and 1.23 cubic centimetres per gram, or between 1.10 cubic centimetres per gram and 1.23 cubic centimetres per gram.

[0038] The first wrapper may have a thickness of greater than or equal to 36 micrometres, greater than or equal to 40 micrometres, greater than or equal to 41 micrometres, greater than or equal to 45 micrometres, greater than or equal to 46 micrometres, greater than or equal to 50 micrometres, greater than or equal to 60 micrometres, greater than or equal to 70 micrometres, or greater than or equal to 80 micrometres.

[0039] The second wrapper may have a thickness of greater than or equal to 36 micrometres, greater than or equal to 40 micrometres, greater than or equal to 41 micrometres, greater than or equal to 45 micrometres, greater than or equal to 46 micrometres, greater than or equal to 50 micrometres, greater than or equal to 60 micrometres, greater than or equal to 70 micrometres, or greater than or equal to 80 micrometres.

[0040] The first wrapper may have a thickness of less than or equal to 90 micrometres, less than or equal to 80 micrometres, less than or equal to 70 micrometres, less than or equal to 60 micrometres, less than or equal to 55 micrometres, less than or equal to 50 micrometres, less than or equal to 46 micrometres, less than or equal to 45 micrometres, less than or equal to 41 micrometres, or less than or equal to 40 micrometres.

[0041] The second wrapper may have a thickness of less than or equal to 90 micrometres, less than or equal to 80 micrometres, less than or equal to 70 micrometres, less than or equal to 60 micrometres, less than or equal to 55 micrometres, less than or equal to 50 micrometres, less than or equal to 46 micrometres, less than or equal to 45 micrometres, less than or equal to 41 micrometres, or less than or equal to 40 micrometres.

[0042] The first wrapper may have a thickness of between 36 micrometres and 90 micrometres, between 36 micrometres and 80 micrometres, between 36 micrometres and 70 micrometres, between 36 micrometres and 60 micrometres, between 36 micrometres and 55 micrometres, between 36 micrometres and 50 micrometres, between 36 micrometres and 46 micrometres, between 36 micrometres and 45 micrometres, between 36 micrometres and 41 micrometres, between 36 micrometres and 40 micrometres, between 40 micrometres and 90 micrometres, between 40 micrometres and 80 micrometres, between 40 micrometres and 70 micrometres, between 40 micrometres and 60 micrometres, between 40 micrometres and 55 micrometres, between 40 micrometres and 50 micrometres, between 40 micrometres and 46 micrometres, between 40 micrometres and 45 micrometres, between 40 micrometres and 41 micrometres, between 41 micrometres and 90 micrometres, between 41 micrometres and 80 micrometres, between 41 micrometres and 70 micrometres, between 41 micrometres and 60 micrometres, between 41 micrometres and 55 micrometres, between 41 micrometres and 50 micrometres, between 41 micrometres and 46 micrometres, between 41 micrometres and 45 micrometres, between 45 micrometres and 90 micrometres, between 45 micrometres and 80 micrometres, between 45 micrometres and 70 micrometres, between 45 micrometres and 60 micrometres, between 45 micrometres and 55 micrometres, between 45 micrometres and 50 micrometres, between 45 micrometres and 46 micrometres, between 46 micrometres and 90 micrometres, between 46 micrometres and 80 micrometres, between 46 micrometres and 70 micrometres, between 46 micrometres and 60 micrometres, between 46 micrometres and 55 micrometres, between 46 micrometres and 50 micrometres, between 50 micrometres and 90 micrometres, between 50 micrometres and 80 micrometres, between 50 micrometres and 70 micrometres, between 50 micrometres and 60 micrometres, between 50 micrometres and 55 micrometres, between 60 micrometres and 90 micrometres, between 60 micrometres and 80 micrometres, between 60 micrometres and 70 micrometres, between 70 micrometres and 90 micrometres, between 70 micrometres and 80 micrometres, or between 80 micrometres and 90 micrometres.

[0043] The second wrapper may have a thickness of between 36 micrometres and 90 micrometres, between 36 micrometres and 80 micrometres, between 36 micrometres and 70 micrometres, between 36 micrometres and 60 micrometres, between 36 micrometres and 55 micrometres, between 36 micrometres and 50 micrometres, between 36 micrometres and 46 micrometres, between 36 micrometres and 45 micrometres, between 36 micrometres and 41 micrometres, between 36 micrometres and 40 micrometres, between 40 micrometres and 90 micrometres, between 40 micrometres and 80 micrometres, between 40 micrometres and 70 micrometres, between 40 micrometres and 60 micrometres, between 40 micrometres and 55 micrometres, between 40 micrometres and 50 micrometres, between 40 micrometres and 46 micrometres, between 40 micrometres and 45 micrometres, between 40 micrometres and 41 micrometres, between 41 micrometres and 90 micrometres, between 41 micrometres and 80 micrometres, between 41 micrometres and 70 micrometres, between 41 micrometres and 60 micrometres, between 41 micrometres and 55 micrometres, between 41 micrometres and 50 micrometres, between 41 micrometres and 46 micrometres, between 41 micrometres and 45 micrometres, between 45 micrometres and 90 micrometres, between 45 micrometres and 80 micrometres, between 45 micrometres and 70 micrometres, between 45 micrometres and 60 micrometres, between 45 micrometres and 55 micrometres, between 45 micrometres and 50 micrometres, between 45 micrometres and 46 micrometres, between 46 micrometres and 90 micrometres, between 46 micrometres and 80 micrometres, between 46 micrometres and 70 micrometres, between 46 micrometres and 60 micrometres, between 46 micrometres and 55 micrometres, between 46 micrometres and 50 micrometres, between 50 micrometres and 90 micrometres, between 50 micrometres and 80 micrometres, between 50 micrometres and 70 micrometres, between 50 micrometres and 60 micrometres, between 50 micrometres and 55 micrometres, between 60 micrometres and 90 micrometres, between 60 micrometres and 80 micrometres, between 60 micrometres and 70 micrometres, between 70 micrometres and 90 micrometres, between 70 micrometres and 80 micrometres, or between 80 micrometres and 90 micrometres.

[0044] The ratio of the thickness of the first wrapper to the width of the rod of aerosol-generating substrate may be between 1:225 and 1:70, between 1:220 and 1:90, between 1:200 and 1:110, or between 1:180 and 1:130.

[0045] The ratio of the thickness of the second wrapper to the width of the rod of aerosol-generating substrate may be between 1:225 and 1:70, between 1:220 and 1:90, between 1:200 and 1:110, or between 1:180 and 1:130.

[0046] Each of the first wrapper and the second wrapper may have a uniform thickness. The thickness of each of the first wrapper and the second wrapper may differ at any point by less than or equal to 10 micrometres, less than or equal to 5 micrometres, less than or equal to 2 micrometres, less than or equal to 1 micrometre, or less than or equal to 0.5 micrometres.

[0047] The first wrapper may have a grammage of greater than or equal to 33.5 grams per square metre, greater than or equal to 36.5 grams per square metre, greater than or equal to 38.5 grams per square metre, greater than or equal to 39.0 grams per square metre, greater than or equal to 50 grams per square metre, or greater than or equal to 60 grams per square metre.

[0048] The second wrapper may have a grammage of greater than or equal to 33.5 grams per square metre, greater than or equal to 36.5 grams per square metre, greater than or equal to 38.5 grams per square metre, greater than or equal to 39.0 grams per square metre, greater than or equal to 50 grams per square metre, or greater than or equal to 60 grams per square metre.

[0049] The first wrapper may have a grammage of less than or equal to 70 grams per square metre, less than or equal to 60 grams per square metre, less than or equal to 50 grams per square metre, less than or equal to 42 grams per square metre, less than or equal to 41.5 grams per square metre, less than or equal to 38.5 grams per square metre, or less than or equal to 36.5 grams per square metre.

[0050] The second wrapper may have a grammage of less than or equal to 70 grams per square metre, less than or equal to 60 grams per square metre, less than or equal to 50 grams per square metre, less than or equal to 42 grams per square metre, less than or equal to 41.5 grams per square metre, less than or equal to 38.5 grams per square metre, or less than or equal to 36.5 grams per square metre.

[0051] The first wrapper may have a grammage of between 33.5 grams per square metre and 70 grams per square metre, between 33.5 grams per square metre and 60 grams per square metre, between 33.5 grams per square metre and 50 grams per square metre, between 33.5 grams per square metre and 42 grams per square metre, between 33.5 grams per square metre and 41.5 grams per square metre, between 33.5 grams per square metre and 38.5 grams per square metre, between 33.5 grams per square metre and 36.5 grams per square metre, between 36.5 grams per square metre and 70 grams per square metre, between 36.5 grams per square metre and 60 grams per square metre, between 36.5 grams per square metre and 50 grams per square metre, between 36.5 grams per square metre and 42 grams per square metre, between 36.5 grams per square metre and 41.5 grams per square metre, between 36.5 grams per square metre and 38.5 grams per square metre, between 38.5 grams per square metre and 70 grams per square metre, between 38.5 grams per square metre and 60 grams per square metre, between 38.5 grams per square metre and 50 grams per square metre, between 38.5 grams per square metre and 42 grams per square metre, between 38.5 grams per square metre and 41.5 grams per square metre, between 39 grams per square metre and 70 grams per square metre, between 39 grams per square metre and 60 grams per square metre, between 39 grams per square metre and 50 grams per square metre, between 39 grams per square metre and 42 grams per square metre, between 39 grams per square metre and 41.5 grams per square metre, between 50 grams per square metre and 70 grams per square metre, between 50 grams per square metre and 60 grams per square metre, or between 60 grams per square metre and 70 grams per square metre.

[0052] Preferably, the first wrapper has a grammage of about 60 grams per square metre. More preferably, the first wrapper has a grammage of about 36 grams per square metre.

[0053] The second wrapper may have a grammage of between 33.5 grams per square metre and 70 grams per square metre, between 33.5 grams per square metre and 60 grams per square metre, between 33.5 grams per square metre and 50 grams per square metre, between 33.5 grams per square metre and 42 grams per square metre, between 33.5 grams per square metre and 41.5 grams per square metre, between 33.5 grams per square metre and 38.5 grams per square metre, between 33.5 grams per square metre and 36.5 grams per square metre, between 36.5 grams per square metre and 70 grams per square metre, between 36.5 grams per square metre and 60 grams per square metre, between 36.5 grams per square metre and 50 grams per square metre, between 36.5 grams per square metre and 42 grams per square metre, between 36.5 grams per square metre and 41.5 grams per square metre, between 36.5 grams per square metre and 38.5 grams per square metre, between 38.5 grams per square metre and 70 grams per square metre, between 38.5 grams per square metre and 60 grams per square metre, between 38.5 grams per square metre and 50 grams per square metre, between 38.5 grams per square metre and 42 grams per square metre, between 38.5 grams per square metre and 41.5 grams per square metre, between 39 grams per square metre and 70 grams per square metre, between 39 grams per square metre and 60 grams per square metre, between 39 grams per square metre and 50 grams per square metre, between 39 grams per square metre and 42 grams per square metre, between 39 grams per square metre and 41.5 grams per square metre, between 50 grams per square metre and 70 grams per square metre, between 50 grams per square metre and 60 grams per square metre, or between 60 grams per square metre and 70 grams per square metre.

[0054] Preferably, the second wrapper has a grammage of about 60 grams per square metre. More preferably, the second wrapper has a grammage of about 39 grams per square metre.

[0055] The aerosol-generating article may have an article length which is defined as the overall length of the article from its downstream end to its upstream end along the longitudinal axis of the aerosol-generating article.

[0056] The article length may be greater than or equal to 30 millimetres, greater than or equal to 35 millimetres, greater than or equal to 40 millimetres, or greater than or equal to 45 millimetres.

[0057] The article length may be less than or equal to 80 millimetres, less than or equal to 70 millimetres, less than or equal to 60 millimetres, or less than or equal to 50 millimetres.

[0058] The article length may be between 30 millimetres and 80 millimetres, between 35 millimetres and 70 millimetres, between 40 millimetres and 60 millimetres, between 45 millimetres and 60 millimetres, between 40 millimetres and 50 millimetres, between 45 millimetres and 50 millimetres, or about 45 millimetres.

[0059] A cross-sectional shape of the article may be approximately constant over the article length. The cross-sectional shape of the article may be substantially circular. The article may have a width perpendicular to the article length, wherein the width is substantially constant along the entire article length.

[0060] The aerosol-generating article may have a width of greater than or equal to 5 millimetres, greater than or equal to 5.5 millimetres, greater than or equal to 6 millimetres, greater than or equal to 6.5 millimetres, or greater than or equal to 7 millimetres.

[0061] The aerosol-generating article may have a width of less than or equal to 10 millimetres, less than or equal to 9 millimetres, less than or equal to 8 millimetres or less than or equal to 7.5 millimetres.

[0062] The aerosol-generating article may have a width of between 3 millimetres and 10 millimetres, between 4 millimetres and 9 millimetres, between 5 millimetres and 8 millimetres, between 5 millimetres and 7.5 millimetres, between 5.5 millimetres and 8 millimetres, between 5.5 millimetres and 7.5 millimetres, between 6 millimetres and 8 millimetres, between 6 millimetres and 7.5 millimetres, between 6.5 millimetres and 8 millimetres, between 6.5 millimetres and 7.5 millimetres, between 7 millimetres and 8 millimetres, or between 7 millimetres and 7.5 millimetres.

[0063] The resistance to draw (RTD) of the aerosol-generating article may be between 10 millimetres of water gauge and 70 millimetres of water gauge, between 20 millimetres of water gauge and 65 millimetres of water gauge, between 30 millimetres of water gauge and 60 millimetres of water gauge, between 35 millimetres of water gauge and 55 millimetres of water gauge, or between 40 millimetres of water gauge and 50 millimetres of water gauge.

[0064] Unless otherwise specified, the resistance to draw (RTD) of a component or the aerosol-generating article is measured in accordance with ISO Standard 6565-2015. The RTD refers the pressure required to force air through the full length of a component. The terms “pressure drop” or “draw resistance” of a component or article may also refer to the “resistance to draw”. Such terms generally refer to the measurements in accordance with ISO Standard 6565-2015 normally carried out at a volumetric flow rate of 17.5 millilitres per second at the output or downstream end of the measured component at a temperature of 22 degrees Celsius, a pressure of 101 kPa (about 760 Torr) and a relative humidity of 60%. Conditions for smoking and smoking machine specifications are set out in ISO Standard 3308 (ISO 3308:2012). Atmosphere for conditioning and testing are set out in ISO Standard 3402 (ISO 3402:1999).

[0065] The resistance to draw (RTD) may be expressed with the units of pressure “millimetre(s) of water gauge” (mmWG).

[0066] Each of the first wrapper and the second wrapper may form at least part of the outer surface of the article. In other words, the outer surface of the article may be defined, at least in part, by the first wrapper and the second wrapper.

[0067] At least part of each of the first wrapper and the second wrapper may be a radially outermost layer of the article. In other words, at least part of each of the first wrapper and the second wrapper are not covered by a further layer.

[0068] The first wrapper may have a first wrapper length along the longitudinal axis of the aerosol-generating article. The first wrapper length may be measured from the upstream end of the first wrapper to the downstream end of the first wrapper.

[0069] The second wrapper may have a second wrapper length along the longitudinal axis of the aerosol-generating article. The second wrapper length may be measured from the upstream end of the second wrapper to the downstream end of the second wrapper. As discussed above, the aerosol-generating article may have an article length along the longitudinal axis of the aerosol-generating article.

[0070] The second wrapper length may be greater than or equal to the first wrapper length. Preferably, the first wrapper length is greater than or equal to the second wrapper length.

[0071] One or both of the first wrapper length and the second wrapper length may each be less than the article length.

[0072] The first wrapper length may be greater than or equal to 30 percent of the article length, greater than or equal to 40 percent of the article length, greater than or equal to 50 percent of the article length, greater than or equal to 60 percent of the article length, greater than or equal to 70 percent of the article length, greater than or equal to 80 percent of the article length, or greater than or equal to 90 percent of the article length.

[0073] The second wrapper length may be greater than or equal to 30 percent of the article length, greater than or equal to 40 percent of the article length, greater than or equal to 50 percent of the article length, greater than or equal to 60 percent of the article length, greater than or equal to 70 percent of the article length, greater than or equal to 80 percent of the article length, or greater than or equal to 90 percent of the article length.

[0074] One of the first wrapper length and the second wrapper length may be substantially equal to the article length. That is, one of the first wrapper and the second wrapper may extend along the entire length of the aerosol-generating article in a direction along the longitudinal axis of the aerosol-generating article.

[0075] The first wrapper length may be less than or equal to 95 percent of the article length, less than or equal to 90 percent of the article length, less than or equal to 80 percent of the article length, less than or equal to 70 percent of the article length, less than or equal to 60 percent of the article length, less than or equal to 50 percent of the article length, or less than or equal to 40 percent of the article length.

[0076] The second wrapper length may be less than or equal to 95 percent of the article length, less than or equal to 90 percent of the article length, less than or equal to 80 percent of the article length, less than or equal to 70 percent of the article length, less than or equal to 60 percent of the article length, less than or equal to 50 percent of the article length, or less than or equal to 40 percent of the article length.

[0077] The first wrapper length may be between 30 percent and 95 percent of the article length, between 30 percent and 90 percent of the article length, between 30 percent and 80 percent of the article length, between 30 percent and 70 percent of the article length, between 30 percent and 60 percent of the article length, between 30 percent and 50 percent of the article length, between 30 percent and 40 percent of the article length, between 40 percent and 95 percent of the article length, between 40 percent and 90 percent of the article length, between 40 percent and 80 percent of the article length, between 40 percent and 70 percent of the article length, between 40 percent and 60 percent of the article length, between 40 percent and 50 percent of the article length, between 50 percent and 95 percent of the article length, between 50 percent and 90 percent of the article length, between 50 percent and 80 percent of the article length, between 50 percent and 70 percent of the article length, between 50 percent and 60 percent of the article length, between 60 percent and 95 percent of the article length, between 60 percent and 90 percent of the article length, between 60 percent and 80 percent of the article length, between 60 percent and 70 percent of the article length, between 70 percent and 95 percent of the article length, between 70 percent and 90 percent of the article length, between 70 percent and 80 percent of the article length, between 80 percent and 95 percent of the article length, between 80 percent and 90 percent of the article length, or between 90 percent and 95 percent of the article length.

[0078] The second wrapper length may be between 30 percent and 95 percent of the article length, between 30 percent and 90 percent of the article length, between 30 percent and 80 percent of the article length, between 30 percent and 70 percent of the article length, between 30 percent and 60 percent of the article length, between 30 percent and 50 percent of the article length, between 30 percent and 40 percent of the article length, between 40 percent and 95 percent of the article length, between 40 percent and 90 percent of the article length, between 40 percent and 80 percent of the article length, between 40 percent and 70 percent of the article length, between 40 percent and 60 percent of the article length, between 40 percent and 50 percent of the article length, between 50 percent and 95 percent of the article length, between 50 percent and 90 percent of the article length, between 50 percent and 80 percent of the article length, between 50 percent and 70 percent of the article length, between 50 percent and 60 percent of the article length, between 60 percent and 95 percent of the article length, between 60 percent and 90 percent of the article length, between 60 percent and 80 percent of the article length, between 60 percent and 70 percent of the article length, between 70 percent and 95 percent of the article length, between 70 percent and 90 percent of the article length, between 70 percent and 80 percent of the article length, between 80 percent and 95 percent of the article length, between 80 percent and 90 percent of the article length, or between 90 percent and 95 percent of the article length.

[0079] The first wrapper length may be greater than or equal to 10 millimetres, greater than or equal to 20 millimetres, greater than or equal to 25 millimetres, greater than or equal to 30 millimetres, or greater than or equal to 40 millimetres.

[0080] The first wrapper length may be less than or equal to 50 millimetres, less than or equal to 40 millimetres, less than or equal to 30 millimetres, less than or equal to 25 millimetres, or less than or equal to 20 millimetres.

[0081] The first wrapper length may be between 10 millimetres and 50 millimetres, between 10 millimetres and 40 millimetres, between 10 millimetres and 30 millimetres, between 10 millimetres and 25 millimetres, between 10 millimetres and 20 millimetres, between 20 millimetres and 50 millimetres, between 20 millimetres and 40 millimetres, between 20 millimetres and 30 millimetres, between 20 millimetres and 25 millimetres, between 25 millimetres and 50 millimetres, between 25 millimetres and 40 millimetres, between 25 millimetres and 30 millimetres, between 30 millimetres and 50 millimetres, between 30 millimetres and 40 millimetres, or between 40 millimetres and 50 millimetres.

[0082] The second wrapper length may be greater than or equal to 10 millimetres, greater than or equal to 20 millimetres, greater than or equal to 25 millimetres, greater than or equal to 30 millimetres, or greater than or equal to 40 millimetres.

[0083] The second wrapper length may be less than or equal to 50 millimetres, less than or equal to 40 millimetres, less than or equal to 30 millimetres, less than or equal to 25 millimetres, or less than or equal to 20 millimetres.

[0084] The second wrapper length may be between 10 millimetres and 50 millimetres, between 10 millimetres and 40 millimetres, between 10 millimetres and 30 millimetres, between 10 millimetres and 25 millimetres, between 10 millimetres and 20 millimetres, between 20 millimetres and 50 millimetres, between 20 millimetres and 40 millimetres, between 20 millimetres and 30 millimetres, between 20 millimetres and 25 millimetres, between 25 millimetres and 50 millimetres, between 25 millimetres and 40 millimetres, between 25 millimetres and 30 millimetres, between 30 millimetres and 50 millimetres, between 30 millimetres and 40 millimetres, or between 40 millimetres and 50 millimetres.

[0085] One or both of the first wrapper and the second wrapper may extend from an upstream end of the article. One or both of the first wrapper and the second wrapper may extend from a downstream end of the article.

[0086] For example, the first wrapper may extend from an upstream end of the article, and the second wrapper may extend from a downstream end of the article.

[0087] A downstream end of the first wrapper may be downstream of a downstream end of the second wrapper. Preferably, a downstream end of the second wrapper is downstream of a downstream end of the first wrapper.

[0088] An upstream end of the second wrapper may be upstream of the upstream end of the first wrapper. Preferably, an upstream end of the first wrapper is upstream of the upstream end of the second wrapper.

[0089] Preferably, each of the first wrapper and the second wrapper does not extend beyond the ends of the aerosol-generating article in a direction parallel to the longitudinal axis.

[0090] One or both of the first wrapper and the second wrapper may be in direct physical contact with at least one of the rod of aerosol-generating substrate and the downstream section. In that case, there is no layer of material between one or both of the first wrapper and the second wrapper and at least one of the rod of aerosol-generating substrate and the downstream section.

[0091] Each of the first wrapper and the second wrapper may be formed from a single continuous sheet of material. Each of the single continuous sheets may be wrapped around at least one of the rod of aerosol-generating substrate and the downstream section by about one turn. Generally, each of the single continuous sheets may be wrapped around at least one of the rod of aerosol-generating substrate and the downstream section by slightly more than one turn, but less than two turns, to form an overlapping region of opposing end portions of each wrapper. The thickness of each wrapper is not to be measured in the overlapping region of the opposing end portions of each wrapper. Each of the first wrapper and the second wrapper may be formed from a single continuous sheet of material and may comprise only a single layer, except for an optional overlapping region of the opposing end portions of each wrapper, if present.

[0092] One or both of the first wrapper and the second wrapper may comprise a cellulosic material, preferably selected from one or more of paper, wood, textile, natural fibres, and artificial fibres. One or both of the first wrapper and the second wrapper may each comprise a paper layer. One or both of the first wrapper and the second wrapper may each be made of a single paper sheet.

[0093] One or both of the first wrapper and the second wrapper may each comprise a single paper layer wrapped around at least one of the rod of aerosol-generating substrate and the downstream section.

[0094] One or both of the first wrapper and the second wrapper may be a paper wrapper or a non-paper wrapper. Suitable non-paper wrappers include, but are not limited to sheets of homogenised tobacco materials.

[0095] Preferably, both of the first wrapper and the second wrapper are each formed from paper.

[0096] One or both of the first wrapper and the second wrapper may be a paper wrapper comprising PVOH (polyvinyl alcohol) or silicone (or polysiloxane). The PVOH may be applied to the paper wrapper as a surface coating, or the paper wrapper may comprise a surface treatment comprising PVOH or silicon.

[0097] Advantageously, surface coatings or surface treatments of PVOH (polyvinyl alcohol) or silicone (or polysiloxane) may improve the grease barrier properties of the wrapper.

[0098] One or both of the first wrapper and the second wrapper may comprise a water-resistant barrier coating on at least a part of an inner surface. The water-resistant barrier coating may comprise one or both of an alkyl ketene dimer (AKD) and a rosin. The water-resistant barrier coating ingredients may be mixed with the fibres of the wrapper during the manufacturing process. The wrapper may be impregnated with the water-resistant barrier coating ingredients.

[0099] Advantageously, providing a water-resistant barrier coating on at least a part of an inner surface of one or both of the first wrapper and the second wrapper may increase the wet tensile strength of the wrapper. Without wishing to be bound by theory, providing a water-resistant barrier coating on at least a part of an inner surface of one or both of the first wrapper and the second wrapper may increase the contact angle of the inner surface of the wrapper which in turn may increase the hydrophobicity and wet tensile strength of the wrapper.

[0100] The grammage of the first wrapper may be equal to the grammage of the second wrapper. The grammage of the first wrapper may be greater than the grammage of the second wrapper. Preferably, the grammage of the second wrapper is greater than the grammage of the first wrapper.

[0101] The thickness of the first wrapper may be equal to the thickness of the second wrapper. The thickness of the first wrapper may be greater than the thickness of the second wrapper. Preferably, the thickness of the second wrapper is greater than the thickness of the first wrapper.

[0102] One or both of the first wrapper and the second wrapper may comprise a printed element on at least one of an outer surface or an inner surface of the wrapper. Only one of the first wrapper and the second wrapper may comprise a printed element on at least one of an outer surface or an inner surface of the wrapper. Preferably, only the second wrapper comprises a printed element on at least one of an outer surface or an inner surface of the wrapper.

[0103] The printed element may comprise at least one of indicia, text, images, letters, words, shapes, logos, colours, graphics, patterns, a coating (such as a lip release coating) or a combination thereof.

[0104] One or both of the first wrapper and the second wrapper may comprise a filler. The filler content of one or both of the first wrapper and the second wrapper may be less than or equal to 30 percent by weight of the wrapper. Preferably, the filler is calcium carbonate.

[0105] One or both of the first wrapper and the second wrapper may comprise one or more perforations or may not comprise any perforations. Perforations through the wrapper may, for example, be achieved through laser perforation.

[0106] The first wrapper may have a permeability of less than or equal to 10 CORESTA units, less than or equal to 7 CORESTA units, less than or equal to 5 CORESTA units or less than or equal to 3 CORESTA units.

[0107] The first wrapper may have a permeability of greater than or equal to 1 CORESTA units, greater than or equal to 3 CORESTA units, greater than or equal to 5 CORESTA units or greater than or equal to 7 CORESTA units.

[0108] The second wrapper may have a permeability of less than or equal to 10 CORESTA units, less than or equal to 7 CORESTA units, less than or equal to 5 CORESTA units or less than or equal to 3 CORESTA units.

[0109] The second wrapper may have a permeability of greater than or equal to 1 CORESTA units, greater than or equal to 3 CORESTA units, greater than or equal to 5 CORESTA units or greater than or equal to 7 CORESTA units.

[0110] The permeability of a wrapper may be determined according to the International Standard test method ISO 2965:2019 and the result may be presented as cubic centimetres per minute per square centimetres and referred to as “CORESTA units”.

[0111] The surface of each of the first wrapper and the second wrapper may comprise a wire side and an anti-wire side opposite the wire side. The wire side of a wrapper is the side of the wrapper that has been formed in contact with the manufacturing machine's forming wire. The wire side of each of the first wrapper and the second wrapper may face inwards. The anti-wire side of each of the first wrapper and the second wrapper may face outwards.

[0112] The wire side of the first wrapper may have a contact angle which is greater than the contact angle of its anti-wire side.

[0113] The side of the first wrapper with the lowest contact angle preferably faces outwards.

[0114] The wire side of the second wrapper may have a contact angle which is greater than the contact angle of its anti-wire side.

[0115] The side of the second wrapper with the lowest contact angle preferably faces outwards.

[0116] Advantageously, providing a wrapper with the lowest contact angle on its outer surface improves the ease with which a printed element can be provided on the outer surface of the wrapper.

[0117] The anti-wire side of the second wrapper may have a contact angle which is greater than or equal to the contact angle of the anti-wire side of the first wrapper. Preferably, the anti-wire side of the first wrapper has a contact angle which is greater than or equal to the contact angle of the anti-wire side of the second wrapper.

[0118] The wire side of the second wrapper may have a contact angle which is greater than or equal to the contact angle of the wire side of the first wrapper. Preferably, the wire side of the first wrapper has a contact angle which is greater than or equal to the contact angle of the wire side of the second wrapper.

[0119] Advantageously, providing a wrapper with a lower contact angle on a surface allows that surface to be more easily provided with a printed element.

[0120] For example, providing a second wrapper with a lower contact angle on its surface than a first wrapper may allow the second wrapper to be more easily provided with a printed element on its surface than the first wrapper. This may, for example, allow the second wrapper to be provided with a printed element and the first wrapper to be provided without a printed element while minimising the cost of the first wrapper.

[0121] At least one of the first wrapper and the second wrapper may have a hydrophobic surface. That is, at least one of the first wrapper and the second wrapper may have a large contact angle on a surface.

[0122] The term “hydrophobic” refers to a surface exhibiting water repelling properties. One way to determine this is to measure the water contact angle, simply referred to herein as the “contact angle”. The “contact angle” is the angle, conventionally measured through the liquid, where a liquid/vapour interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young equation. Hydrophobicity or water contact angle may be determined by utilising TAPPI T558 test method and the result is presented as an interfacial contact angle and reported in “degrees” and can range from near zero to near 180 degrees. The contact angle may also be measured according to EN 828:2013.

[0123] At least one side (for example, one or both of the anti-wire side and the wire side) of the first wrapper may have a contact angle of greater than or equal to 45 degrees, greater than or equal to 50 degrees, greater than or equal to 60 degrees, greater than or equal to 65 degrees, or greater than or equal to 75 degrees.

[0124] At least one side (for example, one or both of the anti-wire side and the wire side) of the second wrapper may have a contact angle of greater than or equal to 45 degrees, greater than or equal to 50 degrees, greater than or equal to 60 degrees, greater than or equal to 65 degrees, or greater than or equal to 75 degrees.

[0125] At least one side (for example, one or both of the anti-wire side and the wire side) of the first wrapper may have a contact angle of less than or equal to 75 degrees, less than or equal to 65 degrees, or less than or equal to 60 degrees.

[0126] At least one side (for example, one or both of the anti-wire side and the wire side) of the second wrapper may have a contact angle of less than or equal to 75 degrees, less than or equal to 65 degrees, or less than or equal to 60 degrees.

[0127] At least one side (for example, one or both of the anti-wire side and the wire side) of the first wrapper may have a contact angle of between 45 degrees and 75 degrees, between 45 degrees and 65 degrees, between 45 degrees and 60 degrees, between 50 degrees and 75 degrees, between 50 degrees and 65 degrees, between 50 degrees and 60 degrees, between 60 degrees and 75 degrees, between 60 degrees and 65 degrees, or between 65 degrees and 75 degrees.

[0128] At least one side (for example, one or both of the anti-wire side and the wire side) of the second wrapper may have a contact angle of between 45 degrees and 75 degrees, between 45 degrees and 65 degrees, between 45 degrees and 60 degrees, between 50 degrees and 75 degrees, between 50 degrees and 65 degrees, between 50 degrees and 60 degrees, between 60 degrees and 75 degrees, between 60 degrees and 65 degrees, or between 65 degrees and 75 degrees.

[0129] One or both of the first wrapper and the second wrapper may be embossed or may not be embossed.

[0130] The term “embossment” is used herein to refer to protrusions formed in the surface of a wrapper. These protrusions may be carved, moulded or stamped into the wrapper. The portion of a wrapper carrying such embossments is said to be embossed.

[0131] One or both of the first wrapper and the second wrapper may have a smoothness (Bekk smoothness number) of a side (for example, their anti-wire side) of between 30 Bekk seconds and 450 Bekk seconds, between 100 Bekk seconds and 200 Bekk seconds, or between 130 Bekk seconds and 170 Bekk seconds.

[0132] One or both of the first wrapper and the second wrapper may have a smoothness (Bekk smoothness number) of a side (for example, their wire side) of between 60 Bekk seconds and 140 Bekk seconds, between 80 Bekk seconds and 120 Bekk seconds, or between 90 Bekk seconds and 110 Bekk seconds.

[0133] Advantageously, providing a wrapper with a greater smoothness (larger Bekk smoothness number) on a surface allows that surface to be more easily provided with a printed element.

[0134] The side of one or both of the first wrapper and the second wrapper with the greatest smoothness preferably faces outwards.

[0135] Advantageously, providing a wrapper with the greatest smoothness on its outer surface improves the ease with which a printed element can be provided on the outer surface of the wrapper.

[0136] The smoothness (Bekk smoothness number) expressed in Bekk seconds may be measured by means of a standard test using a BEKK Smoothness Tester, which creates a vacuum and measures the time it takes for the vacuum to drop from 50.66 kPa to 48.00 kPa. The test is recognised by ISO Standard 5627:1995.

[0137] One or both of the first wrapper and the second wrapper may have a Cobb value of at least one side (for example, one or both of the wire side and anti-wire side) which is less than or equal to 30 grams per square metre, less than or equal to 28 grams per square metre, less than or equal to 26 grams per square metre, less than or equal to 24 grams per square metre, or less than or equal to 22 grams per square metre.

[0138] One or both of the first wrapper and the second wrapper may have a Cobb value of at least one side (for example, one or both of the wire side and anti-wire side) which is greater than or equal to 15 grams per square metre, greater than or equal to 20 grams per square metre, greater than or equal to 22 grams per square metre, greater than or equal to 24 grams per square metre, greater than or equal to 26 grams per square metre, or greater than or equal to 28 grams per square metre.

[0139] One or both of the first wrapper and the second wrapper may have a Cobb value of at least one side (for example, one or both of the wire side and anti-wire side) which is between 15 grams per square metre and 30 grams per square metre, between 20 grams per square metre and 30 grams per square metre, between 22 grams per square metre and 28 grams per square metre, or between 24 grams per square metre and 26 grams per square metre.

[0140] As used herein, the term “Cobb value” refers to the “Cobb60” which is a measurement of the amount of water that is taken up by a defined area of the paper through one-sided contact with water within 60 seconds. The Cobb value may be measured in accordance with ISO 535:2014.

[0141] Advantageously, reducing the Cobb value of a wrapper may decrease the absorption of water into the wrapper which may increase the wet tensile strength of the wrapper.

[0142] The first wrapper and second wrapper may overlap each other. The first wrapper may at least partially overlie the second wrapper. Preferably, the second wrapper at least partially overlies the first wrapper.

[0143] The area of overlap of the first wrapper and the second wrapper may have a length in a direction parallel to a longitudinal axis of the article.

[0144] The length of overlap of the first wrapper and second wrapper in a direction parallel to a longitudinal direction of the article may be equal to the length of one or more of the hollow tubular elements.

[0145] The length of overlap of the first wrapper and second wrapper in a direction parallel to a longitudinal direction of the article may be greater than or equal to 5 millimetres, greater than or equal to 10 millimetres, greater than or equal to 15 millimetres, or greater than or equal to 20 millimetres.

[0146] The length of overlap of the first wrapper and second wrapper in a direction parallel to a longitudinal direction of the article may be less than or equal to 25 millimetres, less than or equal to 20 millimetres, less than or equal to 15 millimetres, or less than or equal to 10 millimetres.

[0147] The length of overlap of the first wrapper and second wrapper in a direction parallel to a longitudinal direction of the article may be between 5 millimetres and 25 millimetres, between 5 millimetres and 20 millimetres, between 5 millimetres and 10 millimetres, between 10 millimetres and 15 millimetres, or between 15 millimetres and 20 millimetres.

[0148] The length of overlap of the first wrapper and second wrapper may be equal to the length of the first wrapper or equal to the length of the second wrapper. In some preferred embodiments, the length of overlap of the first wrapper and second wrapper is equal to the length of the second wrapper. In some preferred embodiments, the first wrapper entirely underlies the second wrapper. The aerosol-generating article comprises a downstream section located downstream of the rod of aerosol-generating substrate.

[0149] The downstream section is preferably located immediately downstream of the rod of aerosol-generating substrate.

[0150] The downstream section preferably extends between the rod of aerosol-generating substrate and a downstream end of the aerosol-generating article. In other words, a downstream end of the aerosol-generating article may coincide with a downstream end of the downstream section.

[0151] The downstream section may have a length that is greater than or equal to 10 millimetres, greater than or equal to 20 millimetres, greater than or equal to 25 millimetres, greater than or equal to 30 millimetres, or greater than or equal to 40 millimetres.

[0152] The downstream section may have a length that is less than or equal to 70 millimetres, less than or equal to 60 millimetres, less than or equal to 50 millimetres, less than or equal to 40 millimetres, less than or equal to 30 millimetres, less than or equal to 25 millimetres, or less than or equal to 20 millimetres.

[0153] The downstream section may have a length that is between 10 millimetres and 70 millimetres, between 10 millimetres and 60 millimetres, between 10 millimetres and 50 millimetres, between 10 millimetres and 40 millimetres, between 10 millimetres and 30 millimetres, between 10 millimetres and 25 millimetres, between 10 millimetres and 20 millimetres, between 20 millimetres and 70 millimetres, between 20 millimetres and 60 millimetres, between 20 millimetres and 50 millimetres, between 20 millimetres and 40 millimetres, between 20 millimetres and 30 millimetres, between 20 millimetres and 25 millimetres, between 25 millimetres and 70 millimetres, between 25 millimetres and 60 millimetres, between 25 millimetres and 50 millimetres, between 25 millimetres and 40 millimetres, between 25 millimetres and 30 millimetres, between 30 millimetres and 70 millimetres, between 30 millimetres and 60 millimetres, between 30 millimetres and 50 millimetres, between 30 millimetres and 40 millimetres, between 40 millimetres and 70 millimetres, between 40 millimetres and 60 millimetres, or between 40 millimetres and 50 millimetres.

[0154] The resistance to draw (RTD) of the downstream section may be greater than or equal to 0 millimetres of water gauge, greater than or equal to 1 millimetres of water gauge, greater than or equal to 2 millimetres of water gauge, greater than or equal to 5 millimetres of water gauge, greater than or equal to 10 millimetres of water gauge, greater than or equal to 16 millimetres of water gauge, or greater than or equal to 17 millimetres of water gauge.

[0155] The resistance to draw (RTD) of the downstream section may be less than or equal to 100 millimetres of water gauge, less than or equal to 50 millimetres of water gauge, less than or equal to 40 millimetres of water gauge, less than or equal to 30 millimetres of water gauge, less than or equal to 20 millimetres of water gauge, or less than or equal to 19 millimetres of water gauge.

[0156] The resistance to draw (RTD) of the downstream section may be between 1 millimetre of water gauge and 100 millimetres of water gauge, between 2 millimetres of water gauge and 50 millimetres of water gauge, between 5 millimetres of water gauge and 40 millimetres of water gauge, between 10 millimetres of water gauge and 30 millimetres of water gauge, between 16 millimetres of water gauge and 20 millimetres of water gauge, between 17 millimetres of water gauge and 19 millimetres of water gauge, or about 18 millimetres of water gauge.

[0157] The downstream section comprises one or more hollow tubular elements.

[0158] The downstream section may comprise a single hollow tubular element. In other words, the downstream section may comprise only one hollow tubular element. Alternatively, the downstream section may comprise two or more hollow tubular elements.

[0159] One of the one or more hollow tubular elements of the downstream section may be provided immediately downstream of the rod of aerosol-generating substrate. In other words, one of the one or more hollow tubular elements may abut a downstream end of the rod of aerosol-generating substrate.

[0160] One of the one or more hollow tubular elements may define an upstream end of the downstream section.

[0161] At least one of the one or more hollow tubular elements may have a wall thickness of between 100 micrometres and 2 millimetres, between 0.8 millimetres and 1.2 millimetres, between 1 millimetres and 2 millimetres, between 1.5 millimetres and 2 millimetres, between 1.6 millimetres and 2 millimetres, between 150 micrometres and 1.5 millimetres, or between 200 micrometres and 1.25 millimetres.

[0162] At least one of the one or more hollow tubular elements preferably have a width that is approximately equal to the width of the aerosol-generating article.

[0163] At least one of the one or more hollow tubular elements may have a width of between 5 millimetres and 10 millimetres, between 5.5 millimetres and 9 millimetres or between 6 millimetres and 8 millimetres.

[0164] The one or more hollow tubular elements may have a lumen. The lumen of the one or more hollow tubular elements may have any cross sectional shape. The lumen of the one or more hollow tubular elements may have a substantially circular cross sectional shape. The width of the lumen of a hollow tubular element may be referred to as an “inner width”. This is to be distinguished from the “width” of the hollow tubular element which, unless specified otherwise, refers to the external width or outer width of the hollow tubular element.

[0165] At least one of the one or more hollow tubular elements may have an inner width of between 2 millimetres and 10 millimetres, between 3 millimetres and 9 millimetres, between 4 millimetres and 8 millimetres, or between 5 millimetres and 7 millimetres.

[0166] At least one of the one or more hollow tubular elements may have a length of greater than or equal to 3 millimetres, greater than or equal to 4 millimetres, greater than or equal to 5 millimetres, greater than equal to 6 millimetres, greater than or equal to 7 millimetres, greater than or equal to 10 millimetres greater than or equal to 15 millimetres, greater than or equal to 20 millimetres, or greater than or equal to 25 millimetres.

[0167] At least one of the one or more hollow tubular elements may have a length of less than or equal to 40 millimetres, less than or equal to 35 millimetres, less than or equal to 30 millimetres, less than or equal to 25 millimetres, less than or equal to 20 millimetres, less than or equal to 15 millimetres, less than or equal to 12 millimetres or less than or equal to 10 millimetres.

[0168] At least one of the one or more hollow tubular elements may have a length of between 5 millimetres and 40 millimetres, between 5 millimetres and 30 millimetres, between 5 millimetres and 25 millimetres, between 5 millimetres and 20 millimetres, between 5 millimetres and 15 millimetres, between 5 millimetres and 10 millimetres, between 10 millimetres and 40 millimetres, between 10 millimetres and 30 millimetres, between 10 millimetres and 25 millimetres, between 10 millimetres and 20 millimetres, or between 10 millimetres and 15 millimetres, between 15 millimetres and 40 millimetres, between 15 millimetres and 30 millimetres, between 15 millimetres and 25 millimetres, between 15 millimetres and 20 millimetres, between 20 millimetres and 40 millimetres, between 20 millimetres and 30 millimetres, between 20 millimetres and 25 millimetres, between 25 millimetres and 40 millimetres, or between 25 millimetres and 30 millimetres.

[0169] At least one of the one or more hollow tubular elements may have a length of between 5 millimetres and 15 millimetres, between 6 millimetres and 15 millimetres, between 7 millimetres and 15 millimetres, between 5 millimetres and 12 millimetres, between 6 millimetres and 12 millimetres, between 7 millimetres and 12 millimetres, between 5 millimetres and 10 millimetres, between 6 millimetres and 10 millimetres, or between 7 millimetres to 10 millimetres.

[0170] The aerosol-generating article may comprise a ventilation zone.

[0171] The ventilation zone may comprise one or more ventilation holes. The one or more ventilation holes may be perforations which may, for example, be achieved through laser perforation. The one or more ventilation holes may be arranged in one or more rows provided circumferentially around the article. Preferably, each circumferential row of holes comprises from 8 to 30 holes.

[0172] The one or more ventilation holes may be provided at a location along the downstream section. The one or more ventilation holes may be provided at a location along at least one of the one or more hollow tubular elements.

[0173] The one or more ventilation holes may be provided at a location along the downstream section which is between 5 millimetres and 25 millimetres from the downstream end of the article, between 10 millimetres and 20 millimetres from the downstream end of the article, or between 12 millimetres and 18 millimetres from the downstream end of the article.

[0174] The one or more ventilation holes may extend through the peripheral wall of the one or more hollow tubular elements. As such, fluid communication may be established between the flow channel internally defined by the one or more hollow tubular elements and the outer environment.

[0175] Advantageously, providing at least one of the one or more ventilated hollow tubular elements provides a particularly efficient cooling of the aerosol. Such rapid cooling of the volatile species released upon heating the aerosol-generating substrate enhances nucleation of aerosol particles.

[0176] The aerosol-generating article may have a ventilation level of greater than or equal to 45 percent, greater than or equal to 50 percent, greater than or equal to 60 percent, or greater than or equal to 70 percent.

[0177] The aerosol-generating article may have a ventilation level of less than or equal to 90 percent, less than or equal to 85 percent, less than or equal to 80 percent, less than or equal to 70 percent or less than or equal to 60 percent.

[0178] As used herein, the term “ventilation level” denotes a volume ratio between of the airflow admitted into the aerosol-generating article via the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the higher the dilution of the aerosol flow delivered to the consumer.

[0179] The one or more ventilation holes may be provided through one or both of the first wrapper and the second wrapper.

[0180] In some embodiments, the aerosol-generating article may be an aerosol-generating article which does not comprise a ventilation zone.

[0181] At least one of the one or more hollow tubular elements may be formed from at least one of: cardboard, paper, a polymeric material, a cellulosic material, cellulose acetate, low density polyethylene (LDPE), and polyhydroxyalkanoate (PHA). Where the hollow tubular element is formed from paper, the paper may be crimped paper, such as crimped heat resistant paper or crimped parchment paper. Preferably, at least one of the one or more hollow tubular elements comprises cellulose acetate tow. The cellulose acetate tow may have a denier per filament of between 2 and 4 and a total denier of between 25 and 40. Preferably, at least one of the one or more hollow tubular elements comprises a hollow acetate tube.

[0182] The one or more hollow tubular elements may comprise a first hollow tubular element and a second hollow tubular element. The first hollow tubular element may be a hollow acetate tube or a cardboard tube. For example, the first hollow tubular element may be a hollow acetate tube (HAT). The second hollow tubular element may be a hollow acetate tube or a cardboard tube. For example, the second hollow tubular element may be a fine hollow acetate tube (FHAT). The inner width of the second hollow tubular element may be larger than the inner width of the first hollow tubular element. The wall thickness of the second hollow tubular element may be smaller than the wall thickness of the first hollow tubular element. For example, the wall thickness of the second hollow tubular element may be between 0.8 millimetres and 1.2 millimetres, such as 1.05 millimetres. For example, the wall thickness of the second hollow tubular element may be between 1.6 millimetres and 2 millimetres, such as 1.9 millimetres. The second hollow tubular element may be arranged downstream of the first hollow tubular element. One or both of the first hollow tubular element and the second hollow tubular element may comprise a ventilation zone. Preferably, the second hollow tubular element comprises a ventilation zone at a location along the second hollow tubular element. The first tubular element may have a length of between 3 millimetres and 13 millimetres, between 6 millimetres and 10 millimetres, between 7 millimetres and 9 millimetres, or about 8 millimetres. The second tubular element may have a length of between 4 millimetres and 14 millimetres, between 7 millimetres and 11 millimetres, between 8 millimetres and 10 millimetres, or about 9 millimetres.

[0183] The one or more hollow tubular elements may comprise a hollow tubular cooling element.

[0184] As used herein, a “hollow tubular cooling element” refers to a component of an aerosol-generating article located downstream of the aerosol-generating substrate such that, in use, an aerosol formed by volatile compounds released from the aerosol-generating substrate passes through and is cooled by the hollow tubular cooling element before being inhaled by the consumer.

[0185] An upstream end of the hollow tubular cooling element may abut a downstream end of the rod of aerosol-generating substrate.

[0186] The hollow tubular cooling element may be a cardboard tube. In some preferred embodiments, the hollow tubular cooling element is a flanged cardboard tube.

[0187] Advantageously, cardboard is a cost-effective material that provides a balance between being deformable in order to provide ease of insertion of the article into an aerosol-generating device and being sufficiently stiff to provide suitable engagement of the article with the interior of the device. A cardboard tube may therefore provide suitable resistance to deformation or compression during use.

[0188] The hollow tubular cooling element may be a paper tube. The hollow tubular cooling element may be a tube formed from spirally wound paper. The hollow tubular cooling element may be formed from a plurality of layers of the paper.

[0189] The hollow tubular cooling element may comprise a polymeric material. For example, the hollow tubular cooling element may comprise a polymeric film. The polymeric film may comprise a cellulosic film. The hollow tubular cooling element may comprise low density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibres. The hollow tubular cooling element may comprise cellulose acetate tow. The cellulose acetate tow may have a denier per filament of between 2 and 4 and a total denier of between 25 and 40. Preferably, the hollow tubular cooling element is formed from cellulose acetate. Preferably, the hollow tubular cooling element comprises a hollow acetate tube.

[0190] The one or more hollow tubular elements may comprise a hollow tubular support element. An upstream end of the hollow tubular support element may abut a downstream end of the rod of aerosol-generating substrate.

[0191] The one or more hollow tubular elements may comprise a hollow tubular support element upstream of the hollow tubular cooling element. An upstream end of the hollow tubular cooling element may abut a downstream end of the hollow tubular support element.

[0192] The hollow tubular support element may be formed from one or more materials selected from the group consisting of: cellulose acetate; cardboard; crimped paper, such as crimped heat resistant paper or crimped parchment paper; and polymeric materials, such as low density polyethylene (LDPE). Preferably, the hollow tubular support element is formed from cellulose acetate. Preferably, the hollow tubular support element comprises a hollow acetate tube.

[0193] The downstream section may further comprise a PLA (poly lactic acid) plug. The PLA plug may comprise crimped PLA. The PLA plug may be downstream of the one or more hollow tubular elements. The PLA plug may be provided as an alternative to a hollow tubular cooling element.

[0194] The hollow tubular support element may be upstream of the PLA plug. An upstream end of the PLA plug may abut a downstream end of the hollow tubular support element.

[0195] The PLA plug may have a length of between 5 millimetres and 40 millimetres, between 5 millimetres and 30 millimetres, between 5 millimetres and 25 millimetres, between 5 millimetres and 20 millimetres, between 5 millimetres and 15 millimetres, between 5 millimetres and 10 millimetres, between 10 millimetres and 40 millimetres, between 10 millimetres and 30 millimetres, between 10 millimetres and 25 millimetres, between 10 millimetres and 20 millimetres, or between 10 millimetres and 15 millimetres, between 15 millimetres and 40 millimetres, between 15 millimetres and 30 millimetres, between 15 millimetres and 25 millimetres, between 15 millimetres and 20 millimetres, between 20 millimetres and 40 millimetres, between 20 millimetres and 30 millimetres, between 20 millimetres and 25 millimetres, between 25 millimetres and 40 millimetres, or between 25 millimetres and 30 millimetres.

[0196] The one or more hollow tubular elements may comprise one or both of a hollow acetate tube (HAT) and a fine hollow acetate tube (FHAT). Such hollow tubes are cylindrical components which may be made from cellulose acetate and provided with centrally arranged axial holes. The HAT may serve as one or more of an airflow-cooling element and an airflow-accelerating element. The FHAT may serve as an airflow-decelerating element.

[0197] The one or more hollow tubular elements may comprise a HAT and a FHAT. The FHAT may be arranged downstream of the HAT. The inner width of the FHAT may be larger than the inner width of the HAT. The wall thickness of the HAT may be larger than the wall thickness of the FHAT. For example, the wall thickness of the HAT may be between 0.8 millimetres and 1.2 millimetres, such as 1.05 millimetres. For example, the wall thickness of the FHAT may be between 1.6 millimetres and 2 millimetres, such as 1.9 millimetres.

[0198] The HAT may have a length of between 3 millimetres and 13 millimetres, between 6 millimetres and 10 millimetres, between 7 millimetres and 9 millimetres, or about 8 millimetres.

[0199] The FHAT may have a length of between 4 millimetres and 14 millimetres, between 7 millimetres and 11 millimetres, between 8 millimetres and 10 millimetres, or about 9 millimetres.

[0200] One or both of the HAT and the FHAT may comprise a ventilation zone. Preferably, the FHAT comprises a ventilation zone at a location along the FHAT. For example, the FHAT may comprise 11 ventilation holes each having a diameter of 0.11 millimetre.

[0201] The one or more hollow tubular elements may provide a negligible level of resistance to draw (RTD). The term “negligible level of RTD” is used to describe an RTD of less than 1 millimetres of water gauge per 10 millimetres of length of the hollow tubular element, preferably less than 0.4 millimetres of water gauge per 10 millimetres of length of the hollow tubular element, more preferably less than 0.1 millimetres of water gauge per 10 millimetres of length of the hollow tubular element.

[0202] The RTD of at least one of the one or more hollow tubular elements is preferably less than or equal to 10 millimetres of water gauge, less than or equal to 5 millimetres of water gauge, less than or equal to 2.5 millimetres of water gauge, less than or equal to 2 millimetres of water gauge, or less than or equal to 1 millimetre of water gauge.

[0203] The RTD of at least one of the one or more hollow tubular elements may be greater than or equal to 0 millimetres of water gauge, greater than or equal to 0.25 millimetres of water gauge, greater than or equal to 0.5 millimetres of water gauge or greater than or equal to 1 millimetre of water gauge.

[0204] The downstream section may comprise a mouthpiece element.

[0205] The mouthpiece element may be located downstream of at least one of the one or more hollow tubular elements. The mouthpiece element may be located downstream of the one or more hollow tubular elements. The mouthpiece element may extend between one of the one or more hollow tubular elements and the downstream end of the aerosol-generating article. The mouthpiece element may extend between the PLA (poly lactic acid) plug and the downstream end of the aerosol-generating article.

[0206] The mouthpiece element may extend to a downstream end of the downstream section. The mouthpiece element may be located at a downstream end of the aerosol-generating article. The downstream end of the mouthpiece element may define the downstream end of the aerosol-generating article.

[0207] The mouthpiece element is preferably a solid plug and is non-tubular. The mouthpiece element may have a substantially uniform cross section.

[0208] The mouthpiece element may be a mouth-end filter. The mouthpiece element may be formed of a fibrous filtration material. The mouthpiece element may be formed of a porous material. The mouthpiece element may be formed of a biodegradable material. The mouthpiece element may be formed of a cellulose material. Preferably, the mouthpiece element is formed of cellulose acetate.

[0209] For example, the mouthpiece element may be formed from a bundle of cellulose acetate fibres having a denier per filament between 10 and 15. For example, the mouthpiece element may be formed from relatively low density cellulose acetate tow, such as cellulose acetate tow comprising fibres of 12 denier per filament.

[0210] Preferably, the mouthpiece element has a low particulate filtration efficiency. Preferably, the mouthpiece element is unventilated such that air does not enter the aerosol-generating article along the mouthpiece element.

[0211] The mouthpiece element may have a length of greater than or equal to 5 millimetres, greater than or equal to 6 millimetres, greater than or equal to 10 millimetres, or greater than or equal to 11 millimetres.

[0212] The mouthpiece element may have a length of less than or equal to 25 millimetres, less than or equal to 20 millimetres, less than or equal to 15 millimetres, less than or equal to 14 millimetres, less than or equal to 13 millimetres, less than or equal to 12 millimetres, less than or equal to 10 millimetres, or less than or equal to 8 millimetres.

[0213] The mouthpiece element may have a length of between 5 millimetres and 25 millimetres, between 10 millimetres and 25 millimetres, between 5 millimetres and 20 millimetres, between 10 millimetres and 20 millimetres, between 10 millimetres and 14 millimetres, between 11 millimetres and 13 millimetres, or about 12 millimetres.

[0214] The mouthpiece element may have a length of between 5 millimetres and 10 millimetres, between 6 millimetres and 8 millimetres, or about 7 millimetres.

[0215] The resistance to draw (RTD) of the mouthpiece element per millimetre length along a longitudinal direction of the aerosol-generating article may be between 0.1 millimetre of water gauge and 20 millimetres of water gauge, between 0.2 millimetre of water gauge and 10 millimetres of water gauge, between 0.5 millimetre of water gauge and 5 millimetres of water gauge, between 1 millimetre of water gauge and 2 millimetres of water gauge, between 1.3 millimetres of water gauge and 1.7 millimetres of water gauge, between 1.4 millimetre of water gauge and 1.6 millimetres of water gauge or about 1.5 millimetres of water gauge.

[0216] The resistance to draw (RTD) of the mouthpiece element may be between 1 millimetre of water gauge and 100 millimetres of water gauge, between 2 millimetres of water gauge and 50 millimetres of water gauge, between 5 millimetres of water gauge and 40 millimetres of water gauge, between 10 millimetres of water gauge and 30 millimetres of water gauge, between 16 millimetres of water gauge and 20 millimetres of water gauge, between 17 millimetres of water gauge and 19 millimetres of water gauge, or about 18 millimetres of water gauge.

[0217] The resistance to draw (RTD) of the mouthpiece element may be between 1 millimetre of water gauge and 60 millimetres of water gauge, between 2 millimetres of water gauge and 30 millimetres of water gauge, between 4 millimetres of water gauge and 25 millimetres of water gauge, between 5 millimetres of water gauge and 18 millimetres of water gauge, between 6 millimetres of water gauge and 13 millimetres of water gauge, between 9 millimetres of water gauge and 12 millimetres of water gauge, or about 10.5 millimetres of water gauge.

[0218] The mouthpiece element may have a width that is approximately equal to the width of the aerosol-generating article. The width of the mouthpiece element may be substantially the same as the width of at least one of the one or more hollow tubular elements.

[0219] The width of the mouthpiece element may be between 5 millimetres and 10 millimetres, between 5.5 millimetres and 9 millimetres, or between 6 millimetres and 8 millimetres.

[0220] The mouthpiece element may comprise a flavourant, which may be provided in any suitable form. For example, the mouthpiece element may comprise one or more capsules, beads or granules of a flavourant, or one or more flavour loaded threads or filaments.

[0221] The aerosol-generating article may comprise a flavour capsule. Preferably, the flavour capsule is located in the mouthpiece element. Preferably, the flavour capsule is a breakable capsule. For example, the flavour capsule may be broken to release flavour contained therein. The capsule may be broken by a force applied by the user when the flavour contained therein is desired. The flavour capsule may comprise an outer wall defining an internal cavity in which the flavour is contained. The outer wall of the flavour capsule may be formed of a pierceable or frangible material.

[0222] The resistance to draw (RTD) characteristics of the downstream section may be wholly or mostly attributed to the RTD characteristics of the mouthpiece element. In other words, the RTD of the mouthpiece element may wholly define the RTD of the downstream section.

[0223] One or more of the components of the aerosol-generating article may be individually circumscribed by their own wrapper which underlie at least one of the first wrapper and the second wrapper.

[0224] At least one of the upstream element, the rod of aerosol-generating substrate and the mouthpiece element may each be circumscribed by individual wrappers which underlie at least one of the first wrapper and the second wrapper.

[0225] The aerosol-generating article comprises a rod of aerosol-generating substrate.

[0226] The rod of aerosol-generating substrate may have one of a polygonal cross-sectional shape, a substantially triangular cross-sectional shape, a substantially oval cross-sectional shape, a substantially rectangular cross-sectional shape, or a substantially circular cross-sectional shape. Preferably, the rod of aerosol-generating substrate has a substantially circular cross-sectional shape.

[0227] The rod of aerosol-generating substrate has a rod width. The rod of aerosol-generating substrate may also have a rod length. The rod length is the maximum dimension of the rod in a longitudinal direction of the aerosol-generating article. The rod width is the maximum dimension of the rod in a transverse direction, perpendicular to the longitudinal direction.

[0228] The rod width may be greater than or equal to 5 millimetres, greater than or equal to 5.5 millimetres, greater than or equal to 6 millimetres, greater than or equal to 6.5 millimetres, or greater than or equal to 7 millimetres.

[0229] The rod width may be less than or equal to 8 millimetres or less than or equal to 7.5 millimetres.

[0230] The rod width may be between 5 millimetres and 8 millimetres, between 5 millimetres and 7.5 millimetres, between 5.5 millimetres and 8 millimetres, between 5.5 millimetres and 7.5 millimetres, between 6 millimetres and 8 millimetres, between 6 millimetres and 7.5 millimetres, between 6.5 millimetres and 8 millimetres, between 6.5 millimetres and 7.5 millimetres, between 7 millimetres and 8 millimetres, or between 7 millimetres and 7.5 millimetres.

[0231] The rod length may be greater than or equal to 1 millimetre, greater than or equal to 3 millimetres, greater than or equal to 5 millimetres, greater than or equal to 7 millimetres, greater than or equal to 9 millimetres, greater than or equal to 10 millimetres, greater than or equal to 11 millimetres, greater than or equal to 12 millimetres, greater than or equal to 13 millimetres, greater than or equal to 14 millimetres, greater than or equal to 15 millimetres, greater than or equal to 16 millimetres, greater than or equal to 18 millimetres, greater than or equal to 20 millimetres, greater than or equal to 22 millimetres, greater than or equal to 25 millimetres, or greater than or equal to 28 millimetres.

[0232] The rod length may be less than or equal to 3 millimetres, less than or equal to 5 millimetres, less than or equal to 7 millimetres, less than or equal to 9 millimetres, less than or equal to 10 millimetres, less than or equal to 11 millimetres, less than or equal to 12 millimetres, less than or equal to 13 millimetres, less than or equal to 14 millimetres, less than or equal to 15 millimetres, less than or equal to 16 millimetres, less than or equal to 18 millimetres, less than or equal to 20 millimetres, less than or equal to 22 millimetres, less than or equal to 25 millimetres, or less than or equal to 30 millimetres.

[0233] The rod length may be between 1 millimetre and 30 millimetres, between 5 millimetres and 22 millimetres, between 8 millimetres and 16 millimetres, between 9 millimetres and 15 millimetres, between 10 millimetres and 14 millimetres, between 10 millimetres and 12 millimetres, between 11 millimetres and 13 millimetres, about 12 millimetres or about 11 millimetres.

[0234] The rod of aerosol-generating substrate comprises an aerosol-generating substrate.

[0235] The rod of aerosol-generating substrate may comprise an aerosol-generating substrate and one or more additional components. For example, the rod of aerosol-generating substrate may comprise a susceptor. For example, the rod of aerosol-generating substrate may comprise a filler material that does not release volatile compounds when heated. The rod of aerosol-generating substrate may comprise a support material onto which the aerosol-generating substrate is deposited, loaded or coated.

[0236] The mass of aerosol-generating substrate in the rod of aerosol-generating substrate may be less than or equal to 300 milligrams, less than or equal to 280 milligrams, less than or equal to 270 milligrams, less than or equal to 260 milligrams, or less than or equal to 250 milligrams. Preferably, the mass of aerosol-generating substrate in the rod of aerosol-generating substrate is less than or equal to 220 milligrams, less than or equal to 210 milligrams, or less than or equal to 200 milligrams.

[0237] The mass of aerosol-generating substrate in the rod of aerosol-generating substrate may be between 10 milligrams and 300 milligrams, between 50 milligrams and 280 milligrams, or between 100 milligrams and 270 milligrams. Preferably, the mass of aerosol-generating substrate in the rod of aerosol-generating substrate is between 10 milligrams and 220 milligrams, between 50 milligrams and 220 milligrams, between 100 milligrams and 220 milligrams, or between 150 milligrams and 200 milligrams.

[0238] As used herein, the mass of aerosol-generating substrate in the rod of aerosol-generating substrate refers to the total mass of aerosol-generating substrate received within the volume defined by the rod of aerosol-generating substrate. To measure the mass of aerosol-generating substrate in the rod of aerosol-generating substrate, the aerosol-generating substrate is removed from the rod of aerosol-generating substrate and is weighed. This may be repeated 20 times for 20 different individual aerosol-generating articles to receive an average value. The mass of aerosol-generating substrate in the rod of aerosol-generating substrate may be the dry mass of aerosol-generating substrate in the rod of aerosol-generating substrate. The mass of the rod of aerosol-generating substrate may be determined after conditioning the aerosol-generating article in accordance with ISO Standard 3402:1999.

[0239] The density of aerosol-generating substrate in the rod of aerosol-generating substrate may be less than or equal to 700 kilograms per cubic metre (0.70 milligrams per cubic millimetre), less than or equal to 650 kilograms per cubic metre (0.65 milligrams per cubic millimetre), less than or equal to 600 kilograms per cubic metre (0.60 milligrams per cubic millimetre), less than or equal to 550 kilograms per cubic metre (0.55 milligrams per cubic millimetre), less than or equal to 500 kilograms per cubic metre (0.50 milligrams per cubic millimetre), less than or equal to 450 kilograms per cubic metre (0.45 milligrams per cubic millimetre), less than or equal to 400 kilograms per cubic metre (0.40 milligrams per cubic millimetre), or less than or equal to 350 kilograms per cubic metre (0.35 milligrams per cubic millimetre).

[0240] The density of aerosol-generating substrate in the rod of aerosol-generating substrate may be greater than or equal to 350 kilograms per cubic metre (0.35 milligrams per cubic millimetre), greater than or equal to 400 kilograms per cubic metre (0.40 milligrams per cubic millimetre), greater than or equal to 450 kilograms per cubic metre (0.45 milligrams per cubic millimetre), greater than or equal to 500 kilograms per cubic metre (0.50 milligrams per cubic millimetre), greater than or equal to 550 kilograms per cubic metre (0.55 milligrams per cubic millimetre), greater than or equal to 600 kilograms per cubic metre (0.60 milligrams per cubic millimetre), greater than or equal to 650 kilograms per cubic metre (0.65 milligrams per cubic millimetre), or greater than or equal to 700 kilograms per cubic metre (0.70 milligrams per cubic millimetre).

[0241] The density of aerosol-generating substrate in the rod of aerosol-generating substrate may be between 350 kilograms per cubic metre (0.35 milligrams per cubic millimetre) and 400 kilograms per cubic metre (0.40 milligrams per cubic millimetre), between 350 kilograms per cubic metre (0.35 milligrams per cubic millimetre) and 500 kilograms per cubic metre (0.50 milligrams per cubic millimetre), between 350 kilograms per cubic metre (0.35 milligrams per cubic millimetre) and 600 kilograms per cubic metre (0.60 milligrams per cubic millimetre), between 350 kilograms per cubic metre (0.35 milligrams per cubic millimetre) and 700 kilograms per cubic metre (0.70 milligrams per cubic millimetre), between 400 kilograms per cubic metre (0.40 milligrams per cubic millimetre) and 450 kilograms per cubic metre (0.45 milligrams per cubic millimetre), between 400 kilograms per cubic metre (0.40 milligrams per cubic millimetre) and 500 kilograms per cubic metre (0.50 milligrams per cubic millimetre), between 400 kilograms per cubic metre (0.40 milligrams per cubic millimetre) and 600 kilograms per cubic metre (0.60 milligrams per cubic millimetre), between 400 kilograms per cubic metre (0.40 milligrams per cubic millimetre) and 700 kilograms per cubic metre (0.70 milligrams per cubic millimetre), between 500 kilograms per cubic metre (0.50 milligrams per cubic millimetre) and 600 kilograms per cubic metre (0.60 milligrams per cubic millimetre), between 500 kilograms per cubic metre (0.50 milligrams per cubic millimetre) and 700 kilograms per cubic metre (0.70 milligrams per cubic millimetre), or between 600 kilograms per cubic metre (0.60 milligrams per cubic millimetre) and 700 kilograms per cubic metre (0.70 milligrams per cubic millimetre)

[0242] The density of the aerosol-generating substrate in the rod of aerosol-generating substrate is calculated by dividing the sum of the mass of the aerosol-generating substrate in the rod of aerosol-generating substrate by the volume of the rod of aerosol-generating substrate (minus the volume taken up by a susceptor if present). The volume of the rod of aerosol-generating substrate is calculated using the dimensions of the aerosol-generating substrate. The mass of the aerosol-generating substrate in the rod of aerosol-generating substrate is determined by removing the aerosol-generating substrate from the rod of aerosol-generating substrate, and weighing the aerosol-generating substrate. This may be repeated 20 times for 20 different individual aerosol-generating articles to receive an average value for the density of the aerosol-generating substrate in the rod of aerosol-generating substrate. The density of aerosol-generating substrate in the rod of aerosol-generating substrate may be calculated on a dry weight basis. The density of aerosol-generating substrate in the rod of aerosol-generating substrate may be determined after conditioning the aerosol-generating article in accordance with ISO Standard 3402:1999.

[0243] The aerosol-generating substrate may be a solid aerosol-generating substrate.

[0244] The aerosol-generating substrate may comprise tobacco material.

[0245] As used herein, the term “tobacco material” is used to describe any material comprising tobacco, including, but not limited to, tobacco leaf, tobacco rib, tobacco stem, tobacco stalk, tobacco dust, expanded tobacco, reconstituted tobacco material and homogenised tobacco material.

[0246] The aerosol-generating substrate in the rod of aerosol-generating substrate the aerosol-generating substrate may comprise homogenised tobacco material. As used herein, the term ‘homogenised tobacco material’ denotes a material formed by agglomerating particulate tobacco.

[0247] The aerosol-generating substrate may comprise one or more sheets of homogenised tobacco material. As used herein, the term ‘sheet’ denotes a laminar element having a width and length substantially greater than the thickness thereof.

[0248] The one or more sheets of tobacco material may each individually have a length substantially the same as the length of the rod of aerosol-generating substrate.

[0249] The aerosol-generating substrate may comprise a gathered sheet of homogenised tobacco material. As used herein, the term ‘gathered’ is used to describe a sheet that is convoluted, folded, or otherwise compressed or constricted substantially transversely to the longitudinal axis of the aerosol-generating article.

[0250] The sheet of homogenised tobacco material may be crimped. As used herein, the term ‘crimped’ denotes a sheet having a plurality of substantially parallel ridges or corrugations. The aerosol-generating substrate may comprise a gathered, crimped sheet of homogenised tobacco material. Preferably, when the aerosol-generating article has been assembled, the substantially parallel ridges or corrugations extend along or parallel to the longitudinal axis of the aerosol-generating article.

[0251] The sheet of homogenised tobacco material may be a cast sheet. The cast sheet of homogenised tobacco material may comprise, prior to the casting process, tobacco particles having an average particle size (D 95) of more than 50 micrometres, between 50 micrometres and 100 micrometres, between 60 micrometres and 80 micrometres, between 65 micrometres and 75 micrometres, or about 70 micrometres.

[0252] As used herein, the term “average particle size (D95)” is used to denote the volume-basis median value of the particle size distribution and is the value of the particle diameter at 95% in the cumulative distribution. The particle size of the particles can be analysed by laser diffraction method.

[0253] The aerosol-generating substrate preferably comprises an aerosol former. The aerosol former may be any suitable known compound or mixture of compounds that, in use, facilitates formation of a dense and stable aerosol. The aerosol former may be facilitating that the aerosol is substantially resistant to thermal degradation at temperatures typically applied during use of the aerosol-generating article. Suitable aerosol formers are for example: polyhydric alcohols such as, for example, triethylene glycol, 1,3-butanediol, propylene glycol and glycerine; esters of polyhydric alcohols such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

[0254] The aerosol former may comprise one or more of glycerine and propylene glycol. The aerosol former may consist of glycerine or propylene glycol or of a combination of glycerine and propylene glycol.

[0255] The aerosol-generating substrate may comprise at least 5 percent, at least 10 percent, or at least 12 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

[0256] The aerosol-generating substrate may comprise less than or equal to 30 percent, less than or equal to 25 percent, or less than or equal to 20 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

[0257] The aerosol-generating substrate may comprise between 5 percent and 30 percent, between 5 percent and 25 percent, or between 5 percent and 20 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

[0258] The aerosol-generating substrate may comprise between about 10 percent and about 30 percent, between about 10 percent and about 25 percent, or between about 10 percent and about 20 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

[0259] The aerosol-generating substrate may comprise between about 12 percent and about 30 percent, between about 12 percent and about 25 percent, or between about 12 percent and about 20 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

[0260] The aerosol-generating substrate may comprise at least one of tobacco material, between about 1 percent to about 5 percent of a binder, and between about 10 percent to about 30 percent of glycerine on a dry weight basis.

[0261] The aerosol-generating substrate may comprise tobacco cut filler and preferably an aerosol-former content in the aerosol-generating substrate is at least about 8 percent by weight of the aerosol-generating substrate.

[0262] The aerosol-generating substrate may comprise strands of reconstituted or reprocessed tobacco. The aerosol-generating substrate may comprise crimped fibre pieces of reconstituted or reprocessed tobacco.

[0263] As used herein, the term “strand” describes an elongate element of material having a length that is substantially greater than the width and thickness thereof. The term “strand” should be considered to encompass strips, shreds and any other homogenised plant material having a similar form. The strands of homogenised plant material may be formed from a sheet of homogenised plant material, for example by cutting or shredding, or by other methods, for example, by an extrusion method.

[0264] The rod of aerosol-generating substrate may comprise at least one of nicotine, one or more aerosol formers, and one or more carboxylic acids.

[0265] The aerosol-generating substrate may comprise at least one of a solid aerosol-generating substrate comprising nicotine, one or more cellulose based agents, one or more aerosol formers, and one or more carboxylic acids.

[0266] As used herein with reference to the invention, the term “nicotine” is used to describe nicotine, a nicotine base or a nicotine salt. The aerosol-generating film may comprise natural nicotine or synthetic nicotine.

[0267] The aerosol-generating film may comprise one or more monoprotic nicotine salts.

[0268] As used herein with reference to the invention, the term “monoprotic nicotine salt” is used to describe a nicotine salt of a monoprotic acid.

[0269] The aerosol-generating film may comprise one or more diprotic nicotine salts.

[0270] As used herein with reference to the invention, the term “diprotic nicotine salt” is used to describe a nicotine salt of a diprotic acid.

[0271] The aerosol-generating film may comprise one or more carboxylic acids. Preferably, the aerosol-generating firm comprises one or more of lactic acid, benzoic acid, fumaric acid and levulinic acid.

[0272] The aerosol-generating substrate may be one of a solid aerosol-generating film or a solid aerosol-generating gel.

[0273] As used herein, the term “film” is used to describe a solid laminar element having a thickness that is less than the width or length thereof. The film may be self-supporting. In other words, a film may have cohesion and mechanical properties such that the film, even if obtained by casting a film-forming formulation on a support surface, can be separated from the support surface. Alternatively, the film may be disposed on a support or sandwiched between other materials. This may enhance the mechanical stability of the film.

[0274] The aerosol-generating substrate may comprise a plurality of shreds of tobacco material, such as tobacco cut filler or shreds of homogenised tobacco material.

[0275] As used herein, the term “shred” denotes an element having a length substantially greater than a width and a thickness thereof.

[0276] Shreds of homogenised tobacco material may be formed from a sheet of homogenised tobacco material, for example, by cutting or shredding. Shreds of homogenised tobacco material may be formed by other methods, for example, by extrusion.

[0277] The shreds of tobacco material may have a width of at least about 0.3 millimetres, at least about 0.5 millimetres, or at least about 0.6 millimetres.

[0278] The shreds of tobacco material may have a width of less than or equal to about 2 millimetres, less than or equal to about 1.2 millimetres, or less than about 0.9 millimetres.

[0279] The shreds of tobacco material may have a width of between about 0.3 millimetres and about 2 millimetres, between about 0.3 millimetres and about 1.2 millimetres, or between about 0.3 millimetres and about 0.9 millimetres.

[0280] The shreds of tobacco material may have a width of between about 0.5 millimetres and about 2 millimetres, between about 0.5 millimetres and about 1.2 millimetres, or between about 0.5 millimetres and about 0.9 millimetres.

[0281] The shreds of tobacco material may have a width of between about 0.6 millimetres and about 2 millimetres, between about 0.6 millimetres and about 1.2 millimetres, or between about 0.6 millimetres and about 0.9 millimetres.

[0282] The shreds of tobacco material may have a length of at least about 10 millimetres.

[0283] The shreds of tobacco material may have a length of less than or equal to about 40 millimetres.

[0284] The shreds of tobacco material may have a length of between about 10 millimetres and about 40 millimetres.

[0285] At least about 20 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may extend along the entire length of the rod of aerosol-generating substrate. At least about 20 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may have a length substantially the same as the length of the rod of aerosol-generating substrate.

[0286] Less than or equal to about 60 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may extend along the entire length of the rod of aerosol-generating substrate. Less than or equal to about 60 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may have a length substantially the same as the length of the rod of aerosol-generating substrate.

[0287] Between about 20 percent and 60 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may extend along the entire length of the rod of aerosol-generating substrate. Between about 20 percent and 60 percent by weight of the plurality of shreds of tobacco material on a dry weight basis may have a length substantially the same as the length of the rod of aerosol-generating substrate.

[0288] The aerosol-generating substrate may comprise a plurality of pellets or granules of tobacco material, such as homogenised tobacco material.

[0289] At least about 60 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 1 millimetre, at least about 70 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 1 millimetre, or at least about 80 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 1 millimetre.

[0290] Where the homogenised plant material is in the form of a plurality of pellets or granules, at least about 70 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 0.5 millimetres, at least about 80 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 0.5 millimetres, or at least about 90 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 0.5 millimetres.

[0291] For example, at least about 80 percent by weight of the plurality of pellets or granules may have a largest dimension greater than about 1 millimetre and at least about 90% by weight of the plurality of pellets or granules may have a largest dimension greater than about 0.5 millimetres.

[0292] The rod of aerosol-generating substrate may comprise a susceptor element arranged within the rod of aerosol-generating substrate.

[0293] As used herein, the term “susceptor” denotes a material that is capable of being heated when penetrated by a varying magnetic field.

[0294] The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. For example, the susceptor element may comprise a metal or carbon. The susceptor element may comprise or consist of a ferromagnetic material, for example a ferromagnetic alloy, ferritic iron, or a ferromagnetic steel or stainless steel. A suitable material may be, or comprise, aluminium. The susceptor element may be formed from 400 series stainless steels, for example grade 410, or grade 420, or grade 430 stainless steel.

[0295] The susceptor element may be at least partly circumscribed by the rod of aerosol-generating substrate. The susceptor element may be completely surrounded by the rod of aerosol-generating substrate.

[0296] The susceptor element may be elongate and may be arranged substantially longitudinally within the rod of aerosol-generating substrate. The susceptor element may be positioned in a radially central position within the rod of aerosol-generating substrate and extend along the longitudinal axis of the aerosol-generating article.

[0297] As used herein, the term “elongate” denotes a component with a length dimension that is greater than its width dimension or its thickness dimension, for example greater than twice its width dimension or its thickness dimension.

[0298] The length of the susceptor element may be less than or equal to the rod length.

[0299] The length of the susceptor element may be less than or equal to 99 percent of the rod length, less than or equal to 95 percent of the rod length, less than or equal to 90 percent of the rod length, less than or equal to 85 percent of the rod length, less than or equal to 80 percent of the rod length, less than or equal to 70 percent of the rod length, less than or equal to 60 percent of the rod length, or less than or equal to 50 percent of the rod length.

[0300] The length of the susceptor element may be greater than or equal to 50 percent of the rod length, greater than or equal to 60 percent of the rod length, greater than or equal to 70 percent of the rod length, greater than or equal to 80 percent of the rod length, greater than or equal to 85 percent of the rod length, greater than or equal to 90 percent of the rod length, greater than equal to 95 percent of the rod length, or greater than equal to 99 percent of the rod length.

[0301] The length of the susceptor element may be between 70 percent and 99 percent of the rod length, between 75 percent and 95 percent of the rod length, between 80 percent and 95 percent of the rod length, or between 85 percent and 95 percent of the rod length.

[0302] The susceptor element may extend along substantially the entire length of the rod of aerosol-generating substrate. Advantageously, this may provide an optimised distribution of heat within the rod of aerosol-generating substrate when the susceptor element is heated.

[0303] The susceptor element may comprise a flat planar portion. The susceptor element may be a flat planar susceptor strip.

[0304] As used herein, the term “flat planar” relates to a generally cuboid shape having a height being significantly smaller than a width and a length. For example, the width and length each may be at least twice the height of the cuboid. The height of the flat planar cuboid may also be referred to as the thickness of the susceptor element, or of the flat planar portion of the susceptor element.

[0305] The susceptor element may have a thickness of between 0.01 millimetre to 2 millimetres, between 0.5 millimetre and 2 millimetres, between 10 micrometres and 500 micrometres, between 10 micrometres and 100 micrometres, between 35 micrometres and 85 micrometres, between 45 micrometres and 75 micrometres, between 55 micrometres and 65 micrometres, between 57 micrometres and 63 micrometres, or between 58 micrometres and 62 micrometres.

[0306] The aerosol-generating article may comprise an upstream section located upstream of the rod of aerosol-generating substrate.

[0307] The upstream section is preferably located immediately upstream of the rod of aerosol-generating substrate. In other words, the upstream section may abut an upstream end of the rod of aerosol-generating substrate. The upstream section may extend between the upstream end of the aerosol-generating article and the rod of aerosol-generating substrate.

[0308] The upstream section may comprise one or more upstream elements.

[0309] The one or more upstream elements may comprise a solid cylindrical plug element having a filled cross-section.

[0310] Advantageously, the one or more upstream elements prevent direct physical contact with the upstream end of the rod of aerosol-generating substrate. Furthermore, the presence of one or more upstream elements helps to prevent any loss of the substrate, which may be advantageous, for example, if the substrate contains particulate plant material. Advantageously, the one or more upstream elements may prevent a heating element, such as a susceptor, from falling out of the aerosol-generating article.

[0311] The one or more upstream elements may be made of a porous material or may comprise a plurality of openings. This may, for example, be achieved through laser perforation. Preferably, the plurality of openings is distributed homogeneously over the cross-section of the upstream element.

[0312] The porosity or permeability of an upstream element may advantageously be designed in order to provide an aerosol-generating article with a particular overall resistance to draw (RTD) without substantially impacting the filtration provided by other portions of the article.

[0313] The one or more upstream elements may comprise a hollow tubular segment defining a longitudinal cavity providing an unrestricted flow channel. In such a case, the resistance to draw (RTD) of the hollow tubular segment may be negligible.

[0314] The one or more upstream elements may, for example, be made of a same material as used for one of the other components of the aerosol-generating article, such as mouthpiece element or the one or more hollow tubular elements. Suitable materials for forming the upstream element include filter materials, ceramic, polymer material, cellulose acetate, cardboard, zeolite or aerosol-generating substrate. The one or more upstream elements may comprise a plug of cellulose acetate. The one or more upstream elements may comprise a hollow acetate tube, or a cardboard tube.

[0315] Preferably, the one or more upstream elements have a width that is approximately equal to the width of the aerosol-generating article.

[0316] The length at least one of the one or more upstream elements along a longitudinal axis of the aerosol-generating article may be between 1 millimetres and 10 millimetres, between 3 millimetres and 7 millimetres, between 4 millimetres and 6 millimetres, or about 5 millimetres.

[0317] The resistance to draw (RTD) of the one or more upstream elements may be between 1 millimetre of water gauge and 150 millimetres of water gauge, between 2 millimetres of water gauge and 50 millimetres of water gauge, between 3 millimetres of water gauge and 20 millimetres of water gauge, or between 4 millimetre of water gauge and 10 millimetres of water gauge.

[0318] The downstream section may comprise an aerosol-forming section. The aerosol-forming section may comprise the rod of aerosol-generating substrate and an intermediate section. The intermediate section may be located downstream of the rod of aerosol-generating substrate. The intermediate section may comprise the one or more hollow tubular elements. The intermediate section may comprise a PLA (poly lactic acid) plug. The mouthpiece element may be located downstream of the intermediate section. The aerosol-forming section may further comprise the upstream section.

[0319] The first wrapper may circumscribe at least part of the aerosol-forming section. The first wrapper may circumscribe the aerosol-forming section along the entire length of the aerosol-forming section. The first wrapper may circumscribe only the aerosol-forming section. The first wrapper may not circumscribe the mouthpiece element.

[0320] The second wrapper may circumscribe one or both of the mouthpiece element and at least part of the aerosol-forming section.

[0321] An aerosol-generating system may be provided. The aerosol-generating system may comprise any of the aerosol-generating articles disclosed above and an aerosol-generating device. The aerosol-generating device may comprise a heating element, or part of a heating element, for heating the aerosol-generating article.

[0322] As used herein, the term “aerosol-generating device” denotes a device that interacts with an aerosol-generating substrate to generate an aerosol. In some examples, the aerosol-generating device heats the aerosol-generating substrate to facilitate release of volatile compounds from the substrate.

[0323] As used herein, the term “aerosol-generating system” refers to the combination of an aerosol-generating device and an aerosol-generating article.

[0324] Since the aerosol-generating system of this disclosure comprises an aerosol-generating article described herein, the advantages specified above for the aerosol-generating articles also apply to the system itself.

[0325] The aerosol-generating device may further comprise a device cavity configured to receive at least a part of the aerosol-generating article. The device cavity may have a closed end and an open end. The aerosol-generating article may be insertable into the device cavity via the open end. The device cavity may have substantially the same cross-sectional shape as the aerosol-generating article.

[0326] The device cavity may have a device cavity length. The device cavity length may be substantially the same as or greater than the rod length. The device cavity length may be such that when the aerosol-generating article is received with the aerosol-generating device greater than or equal to 75 percent of the rod length is received within the device cavity, greater than or equal to 80 percent of the rod length is received within the device cavity, or greater than or equal to 90 percent of the rod length is received within the device cavity.

[0327] Advantageously, providing a device cavity length which is substantially the same as or greater than the rod length may ensure that the entire rod of aerosol-generating substrate can be received in the device cavity which may reduce unsatisfactory heating of downstream portions of the rod of aerosol-generating substrate and may result in more homogeneous heating along the length of the rod.

[0328] The aerosol-generating device may also comprise a heating element.

[0329] The heating element may be in the form of a pin or a blade configured for insertion into the rod of aerosol-generating substrate. The pin or blade may be located in the device cavity. When the aerosol-generating substrate of the aerosol-generating article is received in the device cavity, the pin or blade heating element may penetrate the aerosol-generating substrate, and be inserted into the aerosol-generating substrate to heat the aerosol-generating substrate from the inside.

[0330] When the aerosol-generating article is received by the aerosol-generating device, the pin or blade may penetrate the rod of aerosol-generating substrate substantially through the centre of a cross-sectional face of the rod perpendicular to the rod length.

[0331] Advantageously, providing a pin or blade that penetrates the rod of aerosol-generating substrate substantially through the centre of a cross-sectional face of the rod perpendicular to the rod length may result in more homogeneous heating of the rod of aerosol-generating substrate.

[0332] Alternatively or in addition, the heating element may an external heating element. That is, the heating element may be located around the periphery of the device cavity. The heating element may circumscribe the aerosol-generating article when the aerosol-generating article is at least party received in the device cavity.

[0333] Alternatively or in addition, as discussed above, the rod of aerosol-generating substrate may comprise a heating element in the form of a susceptor element arranged within the rod of aerosol-generating substrate.

[0334] The heating element may comprise one of a resistive heating element and a susceptor element.

[0335] The heating element may comprise a resistive heating element. The heating element may be a resistive heating element. The pin or blade may be a resistive heating element. The external heating element may be a resistive heating element.

[0336] The heating element may comprise an electrically resistive material. Suitable electrically resistive materials include but are not limited to: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, Constantan, nickel-, cobalt-, chromium-, aluminium-, titanium-, zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetal®, iron-aluminium based alloys and iron-manganese-aluminium based alloys. Timetal® is a registered trademark of Titanium Metals Corporation, 1999 Broadway Suite 4300, Denver Colorado. In composite materials, the electrically resistive material may optionally be embedded in, encapsulated or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required. The heating element may comprise a metallic etched foil insulated between two layers of an inert material. In that case, the inert material may comprise Kapton®, all-polyimide or mica foil. Kapton® is a registered trademark of E.I. du Pont de Nemours and Company, 1007 Market Street, Wilmington, Delaware 19898, United States of America.

[0337] The heating element may comprise a susceptor element. The heating element may be a susceptor element. The pin or blade may be a susceptor element. The external heating element may be a susceptor element. A susceptor element may be arranged within the rod of aerosol-generating substrate.

[0338] As used herein, the term “susceptor” denotes a material that is capable of being heated when penetrated by a varying magnetic field.

[0339] The aerosol-generating device may be capable of generating a fluctuating magnetic field of between 1 and 30 MHz, for example, between 2 and 10 MHz, for example between 5 and 7 MHz. The device may be capable of generating a fluctuating magnetic field having a field strength (H-field) of between 1 and 5 kA/m, for example between 2 and 3 kA/m, for example about 2.5 kA/m.

[0340] The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. For example, the susceptor element may comprise a metal or carbon.

[0341] The susceptor element may comprise or consist of a ferromagnetic material, for example a ferromagnetic alloy, ferritic iron, or a ferromagnetic steel or stainless steel. A suitable material may be, or comprise, aluminium. The susceptor element may be formed from 400 series stainless steels, for example grade 410, or grade 420, or grade 430 stainless steel.

[0342] Different materials will dissipate different amounts of energy when positioned within electromagnetic fields having similar values of frequency and field strength. Thus, parameters of the susceptor element, such as material type, length, width, and thickness may all be altered to provide a desired power dissipation within a known electromagnetic field.

[0343] The susceptor element may be heated to a temperature in excess of 250 degrees Celsius.

[0344] Where a susceptor element is provided, the aerosol-generating device may comprise an inductor coil arranged to inductively heat the susceptor element. The aerosol-generating device may comprise an inductor coil. Where the aerosol-generating device comprises a device cavity, the inductor coil may at least partly circumscribe the device cavity. The inductor coil may be arranged to coaxially circumscribe the device cavity.

[0345] The aerosol-generating device may further comprise a controller.

[0346] During use, the heating element may be controlled to operate such that the operating temperature range of the heating element is between 150 degrees Celsius and 350 degrees Celsius, between 200 degrees Celsius and 330 degrees Celsius, or between 260 degrees Celsius and 320 degrees Celsius.

[0347] During use, the heating element may be controlled to heat to a peak temperature of less than or equal to 350 degrees Celsius, less than or equal to 335 degrees Celsius, or less than or equal to 320 degrees Celsius.

[0348] During use, the heating element may be controlled to heat to a peak temperature of between 220 degrees Celsius and 350 degrees Celsius, between 240 degrees Celsius and 335 degrees Celsius, or between 260 degrees Celsius and 320 degrees Celsius.

[0349] The aerosol-generating device may further comprise a power supply. The power supply may be a DC power supply. The power supply may a battery. The power supply may be a nickel-metal hydride battery, a nickel cadmium battery, or a lithium based battery, for example a lithium-cobalt, a lithium-iron-phosphate or a lithium-polymer battery. The power supply may be another form of charge storage device, such as a capacitor. The power supply may require recharging and may have a capacity that allows for the storage of enough energy for one or more user operations, for example one or more aerosol-generating experiences.

[0350] Below, there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0351] Example Ex1: An aerosol-generating article, the aerosol-generating article comprising:

• • [0352] a rod of aerosol-generating substrate;
  • [0353] a downstream section located downstream of the rod of aerosol-generating substrate, the downstream section comprising one or more hollow tubular elements; and
  • [0354] at least two wrappers, the at least two wrappers comprising a first wrapper and a second wrapper, wherein each of the first wrapper and the second wrapper circumscribe at least one of the rod of aerosol-generating substrate and the downstream section, and
  • [0355] wherein each of the first wrapper and the second wrapper have a bulk of less than or equal to 1.42 cubic centimetres per gram.

[0356] Example Ex2: An aerosol-generating article according to example Ex1, wherein one or both of:

• • [0357] the first wrapper has a bulk of greater than or equal to 0.75 cubic centimetres per gram, optionally greater than or equal to 0.80 cubic centimetres per gram, optionally greater than or equal to 0.85 cubic centimetres per gram, optionally greater than or equal to 0.90 cubic centimetres per gram, optionally greater than or equal to 0.93 cubic centimetres per gram, optionally greater than or equal to 0.96 cubic centimetres per gram, or optionally greater than or equal to 1.10 cubic centimetres per gram; and
  • [0358] the second wrapper has a bulk of greater than or equal to 0.75 cubic centimetres per gram, optionally greater than or equal to 0.80 cubic centimetres per gram, optionally greater than or equal to 0.85 cubic centimetres per gram, optionally greater than or equal to 0.90 cubic centimetres per gram, optionally greater than or equal to 0.93 cubic centimetres per gram, optionally greater than or equal to 0.96 cubic centimetres per gram, or optionally greater than or equal to 1.10 cubic centimetres per gram.

[0359] Example Ex3: An aerosol-generating article according to example Ex1 or Ex2, wherein one or both of:

• • [0360] the first wrapper has a bulk of less than or equal to 1.38 cubic centimetres per gram, optionally less than or equal to 1.37 cubic centimetres per gram, optionally less than or equal to 1.30 cubic centimetres per gram, or optionally less than or equal to 1.23 cubic centimetres per gram; and
  • [0361] the second wrapper has a bulk of less than or equal to 1.38 cubic centimetres per gram, optionally less than or equal to 1.37 cubic centimetres per gram, optionally less than or equal to 1.30 cubic centimetres per gram, or optionally less than or equal to 1.23 cubic centimetres per gram.

[0362] Example Ex4: An aerosol-generating article according to any one of examples Ex1 to Ex3, wherein one or both of:

• • [0363] the first wrapper has a bulk of between 0.75 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 1.10 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.75 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 1.10 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.75 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 1.10 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.75 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 1.10 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.75 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.23 cubic centimetres per gram, or optionally between 1.10 cubic centimetres per gram and 1.23 cubic centimetres per gram; and
  • [0364] the second wrapper has a bulk of between 0.75 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 1.10 cubic centimetres per gram and 1.42 cubic centimetres per gram, optionally between 0.75 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 1.10 cubic centimetres per gram and 1.38 cubic centimetres per gram, optionally between 0.75 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 1.10 cubic centimetres per gram and 1.37 cubic centimetres per gram, optionally between 0.75 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 1.10 cubic centimetres per gram and 1.30 cubic centimetres per gram, optionally between 0.75 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.80 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.85 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.90 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.93 cubic centimetres per gram and 1.23 cubic centimetres per gram, optionally between 0.96 cubic centimetres per gram and 1.23 cubic centimetres per gram, or optionally between 1.10 cubic centimetres per gram and 1.23 cubic centimetres per gram.

[0365] Example Ex5: An aerosol-generating article according to any preceding example, wherein one or both of:

• • [0366] the first wrapper has a thickness of greater than or equal to 36 micrometres, optionally greater than or equal to 40 micrometres, optionally greater than or equal to 41 micrometres, optionally greater than or equal to 45 micrometres, optionally greater than or equal to 46 micrometres, optionally greater than or equal to 50 micrometres, optionally greater than or equal to 60 micrometres, optionally greater than or equal to 70 micrometres, or optionally greater than or equal to 80 micrometres; and
  • [0367] the second wrapper has a thickness of greater than or equal to 36 micrometres, optionally greater than or equal to 40 micrometres, optionally greater than or equal to 41 micrometres, optionally greater than or equal to 45 micrometres, optionally greater than or equal to 46 micrometres, optionally greater than or equal to 50 micrometres, optionally greater than or equal to 60 micrometres, optionally greater than or equal to 70 micrometres, or optionally greater than or equal to 80 micrometres.

[0368] Example Ex6: An aerosol-generating article according to any preceding example, wherein one or both of:

• • [0369] the first wrapper has a thickness of less than or equal to 90 micrometres, optionally less than or equal to 80 micrometres, optionally less than or equal to 70 micrometres, optionally less than or equal to 60 micrometres, optionally less than or equal to 55 micrometres, optionally less than or equal to 50 micrometres, optionally less than or equal to 46 micrometres, optionally less than or equal to 45 micrometres, optionally less than or equal to 41 micrometres, or optionally less than or equal to 40 micrometres; and
  • [0370] the second wrapper has a thickness of less than or equal to 90 micrometres, optionally less than or equal to 80 micrometres, optionally less than or equal to 70 micrometres, optionally less than or equal to 60 micrometres, optionally less than or equal to 55 micrometres, optionally less than or equal to 50 micrometres, optionally less than or equal to 46 micrometres, optionally less than or equal to 45 micrometres, optionally less than or equal to 41 micrometres, or optionally less than or equal to 40 micrometres.

[0371] Example Ex7: An aerosol-generating article according to any preceding example, wherein one or both of:

• • [0372] the first wrapper has a thickness of between 36 micrometres and 90 micrometres, optionally between 36 micrometres and 80 micrometres, optionally between 36 micrometres and 70 micrometres, optionally between 36 micrometres and 60 micrometres, optionally between 36 micrometres and 55 micrometres, optionally between 36 micrometres and 50 micrometres, optionally between 36 micrometres and 46 micrometres, optionally between 36 micrometres and 45 micrometres, optionally between 36 micrometres and 41 micrometres, optionally between 36 micrometres and 40 micrometres, optionally between 40 micrometres and 90 micrometres, between 40 micrometres and 80 micrometres, optionally between 40 micrometres and 70 micrometres, optionally between 40 micrometres and 60 micrometres, optionally between 40 micrometres and 55 micrometres, optionally between 40 micrometres and 50 micrometres, optionally between 40 micrometres and 46 micrometres, optionally between 40 micrometres and 45 micrometres, optionally between 40 micrometres and 41 micrometres, optionally between 41 micrometres and 90 micrometres, optionally between 41 micrometres and 80 micrometres, optionally between 41 micrometres and 70 micrometres, optionally between 41 micrometres and 60 micrometres, optionally between 41 micrometres and 55 micrometres, optionally between 41 micrometres and 50 micrometres, optionally between 41 micrometres and 46 micrometres, optionally between 41 micrometres and 45 micrometres, optionally between 45 micrometres and 90 micrometres, optionally between 45 micrometres and 80 micrometres, optionally between 45 micrometres and 70 micrometres, optionally between 45 micrometres and 60 micrometres, optionally between 45 micrometres and 55 micrometres, optionally between 45 micrometres and 50 micrometres, optionally between 45 micrometres and 46 micrometres, optionally between 46 micrometres and 90 micrometres, optionally between 46 micrometres and 80 micrometres, optionally between 46 micrometres and 70 micrometres, optionally between 46 micrometres and 60 micrometres, optionally between 46 micrometres and 55 micrometres, optionally between 46 micrometres and 50 micrometres, optionally between 50 micrometres and 90 micrometres, optionally between 50 micrometres and 80 micrometres, optionally between 50 micrometres and 70 micrometres, optionally between 50 micrometres and 60 micrometres, optionally between 50 micrometres and 55 micrometres, optionally between 60 micrometres and 90 micrometres, optionally between 60 micrometres and 80 micrometres, optionally between 60 micrometres and 70 micrometres, optionally between 70 micrometres and 90 micrometres, optionally between 70 micrometres and 80 micrometres, or optionally between 80 micrometres and 90 micrometres; and
  • [0373] the second wrapper has a thickness of between 36 micrometres and 90 micrometres, optionally between 36 micrometres and 80 micrometres, optionally between 36 micrometres and 70 micrometres, optionally between 36 micrometres and 60 micrometres, optionally between 36 micrometres and 55 micrometres, optionally between 36 micrometres and 50 micrometres, optionally between 36 micrometres and 46 micrometres, optionally between 36 micrometres and 45 micrometres, optionally between 36 micrometres and 41 micrometres, optionally between 36 micrometres and 40 micrometres, optionally between 40 micrometres and 90 micrometres, between 40 micrometres and 80 micrometres, optionally between 40 micrometres and 70 micrometres, optionally between 40 micrometres and 60 micrometres, optionally between 40 micrometres and 55 micrometres, optionally between 40 micrometres and 50 micrometres, optionally between 40 micrometres and 46 micrometres, optionally between 40 micrometres and 45 micrometres, optionally between 40 micrometres and 41 micrometres, optionally between 41 micrometres and 90 micrometres, optionally between 41 micrometres and 80 micrometres, optionally between 41 micrometres and 70 micrometres, optionally between 41 micrometres and 60 micrometres, optionally between 41 micrometres and 55 micrometres, optionally between 41 micrometres and 50 micrometres, optionally between 41 micrometres and 46 micrometres, optionally between 41 micrometres and 45 micrometres, optionally between 45 micrometres and 90 micrometres, optionally between 45 micrometres and 80 micrometres, optionally between 45 micrometres and 70 micrometres, optionally between 45 micrometres and 60 micrometres, optionally between 45 micrometres and 55 micrometres, optionally between 45 micrometres and 50 micrometres, optionally between 45 micrometres and 46 micrometres, optionally between 46 micrometres and 90 micrometres, optionally between 46 micrometres and 80 micrometres, optionally between 46 micrometres and 70 micrometres, optionally between 46 micrometres and 60 micrometres, optionally between 46 micrometres and 55 micrometres, optionally between 46 micrometres and 50 micrometres, optionally between 50 micrometres and 90 micrometres, optionally between 50 micrometres and 80 micrometres, optionally between 50 micrometres and 70 micrometres, optionally between 50 micrometres and 60 micrometres, optionally between 50 micrometres and 55 micrometres, optionally between 60 micrometres and 90 micrometres, optionally between 60 micrometres and 80 micrometres, optionally between 60 micrometres and 70 micrometres, optionally between 70 micrometres and 90 micrometres, optionally between 70 micrometres and 80 micrometres, or optionally between 80 micrometres and 90 micrometres.

[0374] Example Ex8: An aerosol-generating article according to any preceding example, wherein one or both of:

• • [0375] the first wrapper has a grammage of greater than or equal to 33.5 grams per square metre, optionally greater than or equal to 36.5 grams per square metre, optionally greater than or equal to 38.5 grams per square metre, optionally greater than or equal to 39.0 grams per square metre, optionally greater than or equal to 50 grams per square metre, or optionally greater than or equal to 60 grams per square metre; and
  • [0376] the second wrapper has a grammage of greater than or equal to 33.5 grams per square metre, optionally greater than or equal to 36.5 grams per square metre, optionally greater than or equal to 38.5 grams per square metre, optionally greater than or equal to 39.0 grams per square metre, optionally greater than or equal to 50 grams per square metre, or optionally greater than or equal to 60 grams per square metre.

[0377] Example Ex9: An aerosol-generating article according to any preceding example, wherein one or both of:

• • [0378] the first wrapper has a grammage of less than or equal to 70 grams per square metre, optionally less than or equal to 60 grams per square metre, optionally less than or equal to 50 grams per square metre, optionally less than or equal to 42 grams per square metre, optionally less than or equal to 41.5 grams per square metre, optionally less than or equal to 38.5 grams per square metre, or optionally less than or equal to 36.5 grams per square metre; and
  • [0379] the second wrapper has a grammage of less than or equal to 70 grams per square metre, optionally less than or equal to 60 grams per square metre, optionally less than or equal to 50 grams per square metre, optionally less than or equal to 42 grams per square metre, optionally less than or equal to 41.5 grams per square metre, optionally less than or equal to 38.5 grams per square metre, or optionally less than or equal to 36.5 grams per square metre

[0380] Example Ex10: An aerosol-generating article according to any preceding example, wherein one or both of:

• • [0381] the first wrapper has a grammage of between 33.5 grams per square metre and 70 grams per square metre, optionally between 33.5 grams per square metre and 60 grams per square metre, optionally between 33.5 grams per square metre and 50 grams per square metre, between 33.5 grams per square metre and 42 grams per square metre, optionally between 33.5 grams per square metre and 41.5 grams per square metre, optionally between 33.5 grams per square metre and 38.5 grams per square metre, optionally between 33.5 grams per square metre and 36.5 grams per square metre, optionally between 36.5 grams per square metre and 70 grams per square metre, optionally between 36.5 grams per square metre and 60 grams per square metre, optionally between 36.5 grams per square metre and 50 grams per square metre, optionally between 36.5 grams per square metre and 42 grams per square metre, optionally between 36.5 grams per square metre and 41.5 grams per square metre, optionally between 36.5 grams per square metre and 38.5 grams per square metre, optionally between 38.5 grams per square metre and 70 grams per square metre, optionally between 38.5 grams per square metre and 60 grams per square metre, optionally between 38.5 grams per square metre and 50 grams per square metre, optionally between 38.5 grams per square metre and 42 grams per square metre, optionally between 38.5 grams per square metre and 41.5 grams per square metre, optionally between 39 grams per square metre and 70 grams per square metre, optionally between 39 grams per square metre and 60 grams per square metre, optionally between 39 grams per square metre and 50 grams per square metre, optionally between 39 grams per square metre and 42 grams per square metre, optionally between 39 grams per square metre and 41.5 grams per square metre, optionally between 50 grams per square metre and 70 grams per square metre, optionally between 50 grams per square metre and 60 grams per square metre, or optionally between 60 grams per square metre and 70 grams per square metre; and
  • [0382] the second wrapper has a grammage of between 33.5 grams per square metre and 70 grams per square metre, optionally between 33.5 grams per square metre and 60 grams per square metre, optionally between 33.5 grams per square metre and 50 grams per square metre, between 33.5 grams per square metre and 42 grams per square metre, optionally between 33.5 grams per square metre and 41.5 grams per square metre, optionally between 33.5 grams per square metre and 38.5 grams per square metre, optionally between 33.5 grams per square metre and 36.5 grams per square metre, optionally between 36.5 grams per square metre and 70 grams per square metre, optionally between 36.5 grams per square metre and 60 grams per square metre, optionally between 36.5 grams per square metre and 50 grams per square metre, optionally between 36.5 grams per square metre and 42 grams per square metre, optionally between 36.5 grams per square metre and 41.5 grams per square metre, optionally between 36.5 grams per square metre and 38.5 grams per square metre, optionally between 38.5 grams per square metre and 70 grams per square metre, optionally between 38.5 grams per square metre and 60 grams per square metre, optionally between 38.5 grams per square metre and 50 grams per square metre, optionally between 38.5 grams per square metre and 42 grams per square metre, optionally between 38.5 grams per square metre and 41.5 grams per square metre, optionally between 39 grams per square metre and 70 grams per square metre, optionally between 39 grams per square metre and 60 grams per square metre, optionally between 39 grams per square metre and 50 grams per square metre, optionally between 39 grams per square metre and 42 grams per square metre, optionally between 39 grams per square metre and 41.5 grams per square metre, optionally between 50 grams per square metre and 70 grams per square metre, optionally between 50 grams per square metre and 60 grams per square metre, or optionally between 60 grams per square metre and 70 grams per square metre.

[0383] Example Ex11: An aerosol-generating article according to any preceding example, wherein each of the first wrapper and the second wrapper form at least part of the outer surface of the article.

[0384] Example Ex12: An aerosol-generating article according to any preceding example, wherein the first wrapper has a first wrapper length, the second wrapper has a second wrapper length and the aerosol-generating article has an article length.

[0385] Example Ex13: An aerosol-generating article according to example Ex12, wherein one or both of the first wrapper length and the second wrapper length is less than the article length.

[0386] Example Ex14: An aerosol-generating article according to example Ex12 or Ex13, wherein the first wrapper length is greater than or equal to the second wrapper length, optionally wherein the first wrapper length is substantially equal to the article length.

[0387] Example Ex15: An aerosol-generating article according to any one of examples Ex12 to Ex14, wherein one or both of:

• • [0388] the first wrapper length is greater than or equal to 30 percent of the article length, optionally greater than or equal to 40 percent of the article length, optionally greater than or equal to 50 percent of the article length, optionally greater than or equal to 60 percent of the article length, optionally greater than or equal to 70 percent of the article length, optionally greater than or equal to 80 percent of the article length, or optionally greater than or equal to 90 percent of the article length; and
  • [0389] the second wrapper length is greater than or equal to 30 percent of the article length, optionally greater than or equal to 40 percent of the article length, optionally greater than or equal to 50 percent of the article length, optionally greater than or equal to 60 percent of the article length, optionally greater than or equal to 70 percent of the article length, optionally greater than or equal to 80 percent of the article length, or optionally greater than or equal to 90 percent of the article length.

[0390] Example Ex16: An aerosol-generating article according to any one of examples Ex12 to Ex15, wherein one or both of:

• • [0391] the first wrapper length is less than or equal to 95 percent of the article length, optionally less than or equal to 90 percent of the article length, optionally less than or equal to 80 percent of the article length, optionally less than or equal to 70 percent of the article length, optionally less than or equal to 60 percent of the article length, optionally less than or equal to 50 percent of the article length, or optionally less than or equal to 40 percent of the article length; and
  • [0392] the second wrapper length is less than or equal to 95 percent of the article length, optionally less than or equal to 90 percent of the article length, optionally less than or equal to 80 percent of the article length, optionally less than or equal to 70 percent of the article length, optionally less than or equal to 60 percent of the article length, optionally less than or equal to 50 percent of the article length, or optionally less than or equal to 40 percent of the article length.

[0393] Example Ex17: An aerosol-generating article according to any one of examples Ex12 to Ex16, wherein one or both of:

• • [0394] the first wrapper length is between 30 percent and 95 percent of the article length, optionally between 30 percent and 90 percent of the article length, optionally between 30 percent and 80 percent of the article length, optionally between 30 percent and 70 percent of the article length, optionally between 30 percent and 60 percent of the article length, optionally between 30 percent and 50 percent of the article length, optionally between 30 percent and 40 percent of the article length, optionally between 40 percent and 95 percent of the article length, optionally between 40 percent and 90 percent of the article length, optionally between 40 percent and 80 percent of the article length, optionally between 40 percent and 70 percent of the article length, optionally between 40 percent and 60 percent of the article length, optionally between 40 percent and 50 percent of the article length, optionally between 50 percent and 95 percent of the article length, optionally between 50 percent and 90 percent of the article length, optionally between 50 percent and 80 percent of the article length, optionally between 50 percent and 70 percent of the article length, optionally between 50 percent and 60 percent of the article length, optionally between 60 percent and 95 percent of the article length, optionally between 60 percent and 90 percent of the article length, optionally between 60 percent and 80 percent of the article length, optionally between 60 percent and 70 percent of the article length, optionally between 70 percent and 95 percent of the article length, optionally between 70 percent and 90 percent of the article length, optionally between 70 percent and 80 percent of the article length, optionally between 80 percent and 95 percent of the article length, optionally between 80 percent and 90 percent of the article length, or optionally between 90 percent and 95 percent of the article length; and
  • [0395] the second wrapper length is between 30 percent and 95 percent of the article length, optionally between 30 percent and 90 percent of the article length, optionally between 30 percent and 80 percent of the article length, optionally between 30 percent and 70 percent of the article length, optionally between 30 percent and 60 percent of the article length, optionally between 30 percent and 50 percent of the article length, optionally between 30 percent and 40 percent of the article length, optionally between 40 percent and 95 percent of the article length, optionally between 40 percent and 90 percent of the article length, optionally between 40 percent and 80 percent of the article length, optionally between 40 percent and 70 percent of the article length, optionally between 40 percent and 60 percent of the article length, optionally between 40 percent and 50 percent of the article length, optionally between 50 percent and 95 percent of the article length, optionally between 50 percent and 90 percent of the article length, optionally between 50 percent and 80 percent of the article length, optionally between 50 percent and 70 percent of the article length, optionally between 50 percent and 60 percent of the article length, optionally between 60 percent and 95 percent of the article length, optionally between 60 percent and 90 percent of the article length, optionally between 60 percent and 80 percent of the article length, optionally between 60 percent and 70 percent of the article length, optionally between 70 percent and 95 percent of the article length, optionally between 70 percent and 90 percent of the article length, optionally between 70 percent and 80 percent of the article length, optionally between 80 percent and 95 percent of the article length, optionally between 80 percent and 90 percent of the article length, or optionally between 90 percent and 95 percent of the article length.

[0396] Example Ex18: An aerosol-generating article according to any preceding example, wherein one or both of the first wrapper and the second wrapper extends from an upstream end of the article.

[0397] Example Ex19: An aerosol-generating article according to any preceding example, wherein one or both of the first wrapper and the second wrapper extends from a downstream end of the article.

[0398] Example Ex20: An aerosol-generating article according to any preceding example, wherein the first wrapper extends from an upstream end of the article, and wherein the second wrapper extends from a downstream end of the article.

[0399] Example Ex21: An aerosol-generating article according to any preceding example, wherein a downstream end of the second wrapper is downstream of a downstream end of the first wrapper.

[0400] Example Ex22: An aerosol-generating article according to any preceding example, wherein an upstream end of the first wrapper is upstream of an upstream end of the second wrapper.

[0401] Example Ex23: An aerosol-generating article according to any preceding example, wherein one or both of the first wrapper and the second wrapper comprise a cellulosic material, optionally selected from one or more of paper, wood, textile, natural fibres, and artificial fibres.

[0402] Example Ex24: An aerosol-generating article according to any preceding example, wherein one or both of the first wrapper and the second wrapper comprise a water-resistant barrier coating on at least a part of an inner surface, optionally wherein the water-resistant barrier coating comprises one or both of an alkyl ketene dimer (AKD) and a rosin.

[0403] Example Ex25: An aerosol-generating article according to any preceding example, wherein the grammage of the second wrapper is greater than the grammage of the first wrapper.

[0404] Example Ex26: An aerosol-generating article according to any preceding example, wherein the thickness of the second wrapper is greater than the thickness of the first wrapper.

[0405] Example Ex27: An aerosol-generating article according to any preceding example, wherein one or both of the first wrapper and the second wrapper comprise a printed element on at least one of an inner surface or an outer surface of the wrapper, optionally wherein only one of the first wrapper and the second wrapper comprise a printed element on at least one of an inner surface or an outer surface of the wrapper, optionally wherein only the second wrapper comprises a printed element on at least one of an inner surface or an outer surface of the wrapper, optionally wherein the printed element comprises at least one of indicia, text, images, letters, words, shapes, logos, colours, graphics, patterns, coating or a combination thereof.

[0406] Example Ex28: An aerosol-generating article according to any preceding example, wherein one or both of the first wrapper and the second wrapper comprise a filler, optionally wherein the filler content of one or both of the first wrapper and the second wrapper is less than or equal to 30 percent by weight of the wrapper, optionally wherein the filler is calcium carbonate.

[0407] Example Ex29: An aerosol-generating article according to any preceding example, wherein the surface of each of the first wrapper and the second wrapper comprises a wire side and an anti-wire side opposite the wire side, optionally wherein the anti-wire side faces outwards.

[0408] Example Ex30: An aerosol-generating article according to example Ex29, wherein one or both of:

• • [0409] the anti-wire side of the first wrapper has a contact angle which is greater than or equal to the contact angle of the anti-wire side of the second wrapper; and
  • [0410] the wire side of the first wrapper has a contact angle which is greater than or equal to the contact angle of the wire side of the second wrapper.

[0411] Example Ex31: An aerosol-generating article according to example Ex29 or Ex30, wherein one or both of:

• • [0412] at least one of the anti-wire side and the wire side of the first wrapper has a contact angle of greater than or equal to 45 degrees, optionally greater than or equal to 50 degrees, optionally greater than or equal to 60 degrees, optionally greater than or equal to 65 degrees, or optionally greater than or equal to 73 degrees; and
  • [0413] at least one of the anti-wire side and the wire side of the second wrapper has a contact angle of greater than or equal to 45 degrees, optionally greater than or equal to 50 degrees, optionally greater than or equal to 60 degrees, optionally greater than or equal to 65 degrees, or optionally greater than or equal to 73 degrees.

[0414] Example Ex32: An aerosol-generating article according to any one of examples Ex29 to Ex31, wherein one or both of:

• • [0415] at least one of the anti-wire side and the wire side of the first wrapper has a contact angle of less than or equal to 73 degrees, optionally less than or equal to 65 degrees, or optionally less than or equal to 60 degrees; and
  • [0416] at least one of the anti-wire side and the wire side of the second wrapper has a contact angle of less than or equal to 73 degrees, optionally less than or equal to 65 degrees, or optionally less than or equal to 60 degrees.

[0417] Example Ex33: An aerosol-generating article according to any one of examples Ex29 to Ex32, wherein one or both of:

• • [0418] at least one of the anti-wire side and the wire side of the first wrapper has a contact angle of between 45 degrees and 75 degrees, optionally between 45 degrees and 65 degrees, optionally between 45 degrees and 60 degrees, optionally between 50 degrees and 73 degrees, optionally between 50 degrees and 65 degrees, optionally between 50 degrees and 60 degrees, optionally between 60 degrees and 73 degrees, optionally between 60 degrees and 65 degrees, or optionally between 65 degrees and 73 degrees; and
  • [0419] at least one of the anti-wire side and the wire side of the second wrapper has a contact angle of between 45 degrees and 75 degrees, optionally between 45 degrees and 65 degrees, optionally between 45 degrees and 60 degrees, optionally between 50 degrees and 73 degrees, optionally between 50 degrees and 65 degrees, optionally between 50 degrees and 60 degrees, optionally between 60 degrees and 73 degrees, optionally between 60 degrees and 65 degrees, or optionally between 65 degrees and 73 degrees.

[0420] Example Ex34: An aerosol-generating article according to any preceding example, wherein the first wrapper and second wrapper overlap each other, optionally wherein the second wrapper overlies the first wrapper.

[0421] Example Ex35: An aerosol-generating article according to example Ex34, wherein the length of overlap of the first wrapper and second wrapper in a direction parallel to a longitudinal direction of the article is equal to the length of one or more of the hollow tubular elements.

[0422] Example Ex36: An aerosol-generating article according to example Ex34 or Ex35, wherein the length of overlap of the first wrapper and second wrapper in a direction parallel to a longitudinal direction of the article is greater than or equal to 5 millimetres, optionally greater than or equal to 10 millimetres, optionally greater than or equal to 15 millimetres, or optionally greater than or equal to 20 millimetres.

[0423] Example Ex37: An aerosol-generating article according to any one of examples Ex34 to Ex36, wherein the length of overlap of the first wrapper and second wrapper in a direction parallel to a longitudinal direction of the article is less than or equal to 25 millimetres, optionally less than or equal to 20 millimetres, optionally less than or equal to 15 millimetres, or optionally less than or equal to 10 millimetres.

[0424] Example Ex38: An aerosol-generating article according to any one of examples Ex34 to Ex37, wherein the length of overlap of the first wrapper and second wrapper in a direction parallel to a longitudinal direction of the article is equal to the length of the second wrapper.

[0425] Example Ex39: An aerosol-generating article according to any preceding example, wherein the downstream section extends between the rod of aerosol-generating substrate and a downstream end of the aerosol-generating article.

[0426] Example Ex40: An aerosol-generating article according to any preceding example, wherein the downstream section has a length that is greater than or equal to 10 millimetres, optionally greater than or equal to 20 millimetres, optionally greater than or equal to 25 millimetres, optionally greater than or equal to 30 millimetres, or optionally greater than or equal to 40 millimetres.

[0427] Example Ex41: An aerosol-generating article according to any preceding example, wherein the downstream section has a length that is less than or equal to 70 millimetres, optionally less than or equal to 60 millimetres, optionally less than or equal to 50 millimetres, optionally less than or equal to 40 millimetres, optionally less than or equal to 30 millimetres, optionally less than or equal to 25 millimetres, or optionally less than or equal to 20 millimetres.

[0428] Example Ex42: An aerosol-generating article according to any preceding example, wherein the downstream section has a length that is between 10 millimetres and 70 millimetres, optionally between 10 millimetres and 60 millimetres, optionally between 10 millimetres and 50 millimetres, optionally between 10 millimetres and 40 millimetres, optionally between 10 millimetres and 30 millimetres, optionally between 10 millimetres and 25 millimetres, optionally between 10 millimetres and 20 millimetres, between 20 millimetres and 70 millimetres, optionally between 20 millimetres and 60 millimetres, optionally between 20 millimetres and 50 millimetres, optionally between 20 millimetres and 40 millimetres, optionally between 20 millimetres and 30 millimetres, optionally between 20 millimetres and 25 millimetres, optionally between 25 millimetres and 70 millimetres, optionally between 25 millimetres and 60 millimetres, optionally between 25 millimetres and 50 millimetres, optionally between 25 millimetres and 40 millimetres, optionally between 25 millimetres and 30 millimetres, optionally between 30 millimetres and 70 millimetres, optionally between 30 millimetres and 60 millimetres, optionally between 30 millimetres and 50 millimetres, optionally between 30 millimetres and 40 millimetres, optionally between 40 millimetres and 70 millimetres, optionally between 40 millimetres and 60 millimetres, or optionally between 40 millimetres and 50 millimetres.

[0429] Example Ex43: An aerosol-generating article according to any preceding example, wherein one of the one or more hollow tubular elements of the downstream section abuts a downstream end of the rod of aerosol-generating substrate.

[0430] Example Ex44: An aerosol-generating article according to any preceding example, wherein at least one of the one or more hollow tubular elements is formed from at least one of: cardboard, paper, a polymeric material, a cellulosic material, cellulose acetate, low density polyethylene (LDPE), and polyhydroxyalkanoate (PHA).

[0431] Example Ex45: An aerosol-generating article according to any preceding example, wherein the one or more hollow tubular elements comprise a hollow tubular cooling element, optionally wherein an upstream end of the hollow tubular cooling element abuts a downstream end of the rod of aerosol-generating substrate, optionally wherein the hollow tubular cooling element is a cardboard tube, optionally wherein the hollow tubular cooling element is a flanged cardboard tube.

[0432] Example Ex46: An aerosol-generating article according to any preceding example, wherein the one or more hollow tubular elements comprise a hollow tubular support element, optionally wherein an upstream end of the hollow tubular support element abuts a downstream end of the rod of aerosol-generating substrate.

[0433] Example Ex47: An aerosol-generating article according to example Ex46, wherein the hollow tubular support element is formed from one or more materials selected from the group consisting of: cellulose acetate; cardboard; crimped paper, such as crimped heat resistant paper or crimped parchment paper; and polymeric materials, such as low density polyethylene (LDPE).

[0434] Example Ex48: An aerosol-generating article according to any preceding example, wherein the one or more hollow tubular elements comprise a hollow tubular support element upstream of a hollow tubular cooling element, and optionally wherein an upstream end of the hollow tubular cooling element abuts a downstream end of the hollow tubular support element.

[0435] Example Ex49: An aerosol-generating article according to any preceding example, wherein the downstream section further comprises a PLA (poly lactic acid) plug, optionally wherein the PLA plug comprises crimped PLA, optionally wherein the PLA plug is downstream of the one or more hollow tubular elements.

[0436] Example Ex50: An aerosol-generating article according to example Ex49, wherein the one or more hollow tubular elements comprise a hollow tubular support element upstream of the PLA plug, optionally wherein an upstream end of the PLA plug abuts a downstream end of the hollow tubular support element.

[0437] Example Ex51: An aerosol-generating article according to any preceding example, wherein the one or more hollow tubular elements comprise a first hollow tubular element and a second hollow tubular element, optionally wherein the second hollow tubular element is arranged downstream of the first hollow tubular element, optionally wherein an inner diameter of the second hollow tubular element is larger than an inner diameter of the first hollow tubular element, optionally wherein a wall thickness of the second hollow tubular element is smaller than a wall thickness of the first hollow tubular element, optionally wherein the first hollow tubular element comprises a hollow acetate tube (HAT), optionally wherein the second hollow tubular element comprises a fine hollow acetate tube (FHAT).

[0438] Example Ex52: An aerosol-generating article according to any preceding example, wherein the downstream section comprises a mouthpiece element.

[0439] Example Ex53: An aerosol-generating article according to example Ex52, wherein the mouthpiece element is located downstream of at least one of the one or more hollow tubular elements.

[0440] Example Ex54: An aerosol-generating article according to example Ex52 or Ex53, wherein the mouthpiece element is located at the downstream end of the aerosol-generating article.

[0441] Example Ex55: An aerosol-generating article according to any one of examples Ex52 to Ex54, wherein the mouthpiece element is formed of a fibrous filtration material, and optionally wherein the mouthpiece element is formed of cellulose acetate.

[0442] Example Ex56: An aerosol-generating article according to any one of examples Ex52 to Ex55, wherein the aerosol-generating article comprises a flavour capsule, optionally wherein the flavour capsule is located in the mouthpiece element, optionally wherein the flavour capsule is breakable.

[0443] Example Ex57: An aerosol-generating article according to any preceding example, wherein the rod of aerosol-generating substrate comprises at least one of nicotine, one or more aerosol formers, and one or more carboxylic acids.

[0444] Example Ex58: An aerosol-generating article according to any preceding example, wherein the rod of aerosol-generating substrate comprises homogenised tobacco material, optionally the aerosol-generating substrate comprises a gathered sheet of homogenised tobacco material, optionally wherein the homogenized tobacco material is a cast sheet.

[0445] Example Ex59: An aerosol-generating article according to any preceding example, wherein the rod of aerosol-generating substrate comprises a susceptor element arranged within the rod of aerosol-generating substrate.

[0446] Example Ex60: An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an article length of between 30 millimetres and 80 millimetres, optionally between 35 millimetres and 70 millimetres, optionally between 40 millimetres and 60 millimetres, optionally between 45 millimetres and 60 millimetres, optionally between 40 millimetres and 50 millimetres, optionally between 45 millimetres and 50 millimetres, or optionally about 45 millimetres.

[0447] Example Ex61: An aerosol-generating article according to any preceding example, wherein the aerosol-generating article comprises ventilation zone.

[0448] Example Ex62: An aerosol-generating article according to example Ex61, wherein the ventilation zone comprises one or more ventilation holes, optionally wherein the one or more ventilation holes are arranged in one or more rows provided circumferentially around the article.

[0449] Example Ex63: An aerosol-generating article according to example Ex62, wherein the one or more ventilation holes are provided through at least one of the one or more hollow tubular elements.

[0450] Example Ex64: An aerosol-generating article according to Example Ex62 or Ex63, wherein the one or more ventilation holes are provided through one or both of the first wrapper and the second wrapper.

[0451] Example Ex65: An aerosol-generating article according to any preceding example, wherein the aerosol-generating article has an article length and wherein a cross-sectional shape of the article is approximately constant over the article length, optionally wherein the cross-sectional shape of the article is substantially circular, optionally wherein the article has a width perpendicular to the article length, the width being substantially constant along the entire article length.

[0452] Example Ex66: An aerosol-generating article according to any preceding example, wherein the aerosol-generating article comprises an upstream section located upstream of the rod of aerosol-generating substrate, optionally wherein the upstream section extends between the upstream end of the aerosol-generating article and the rod of aerosol-generating substrate.

[0453] Example Ex67: An aerosol-generating article according to example Ex66, wherein the upstream section comprises one or more upstream elements, optionally wherein the one or more upstream elements comprise one or both of a hollow tubular segment and a solid cylindrical plug element having a filled cross-section.

[0454] Example Ex68: An aerosol-generating article according to any one of examples Ex52 to Ex67, wherein the aerosol-generating article comprises an aerosol-forming section, the aerosol-forming section comprising:

• • [0455] the rod of aerosol-generating substrate;
  • [0456] an intermediate section located downstream of the rod of aerosol-generating substrate, the intermediate section comprising the one or more hollow tubular elements, optionally wherein the intermediate section comprises a PLA (poly lactic acid) plug;
  • [0457] wherein the mouthpiece element is located downstream of the intermediate section.

[0458] Example Ex69: An aerosol-generating article according to example Ex68 and example Ex66 or Ex67, wherein the aerosol-forming section further comprises the upstream section.

[0459] Example Ex70: An aerosol-generating article according to example Ex68 or Ex69, wherein the first wrapper circumscribes at least part of the aerosol-forming section, optionally wherein the first wrapper circumscribes the aerosol-forming section along the entire length of the aerosol-forming section, optionally wherein the first wrapper circumscribes only the aerosol-forming section.

[0460] Example Ex71: An aerosol-generating article according to any one of examples Ex68 to Ex70, wherein the second wrapper circumscribes the mouthpiece element, optionally wherein the second wrapper circumscribes at least part of the aerosol-forming section.

[0461] Example Ex72: An aerosol-generating system comprising:

• • [0462] an aerosol-generating article according to any one of examples Ex1 to Ex71; and
  • [0463] an aerosol-generating device configured to heat the aerosol-generating article.

[0464] Example Ex73: The aerosol-generating system according to example Ex72, wherein the aerosol-generating device comprises a device cavity configured to receive at least a part of the aerosol-generating article.

[0465] Example Ex74: The aerosol-generating system according to example Ex73, wherein the device cavity has a closed end and an open end, optionally wherein the aerosol-generating article is insertable into the device cavity via the open end, and optionally the device cavity has substantially the same cross-sectional shape as the aerosol-generating article.

[0466] Example Ex75: The aerosol-generating system according to any one of examples Ex72 to Ex74, wherein the aerosol-generating device comprises a heating element, optionally wherein the heating element is one of a resistive heating element and a susceptor element.

[0467] Example Ex76: The aerosol-generating system according to any one of examples Ex72 to Ex75, wherein the aerosol-generating device comprises an inductor coil, optionally wherein the inductor coil at least partly circumscribes the device cavity, and optionally wherein the inductor coil is arranged to coaxially circumscribe the device cavity.

[0468] Example Ex77: The aerosol-generating system according to any one of examples Ex72 to Ex76, wherein the aerosol-generating device comprises a heating element in the form of a pin or a blade configured for insertion into the rod of aerosol-generating substrate of the aerosol-generating article, optionally wherein the pin or blade comprises one of a resistive heating element and a susceptor element.

[0469] Example Ex78: The aerosol-generating system according to example Ex77, wherein when the aerosol-generating article is received by the aerosol-generating device, the pin or blade penetrates the rod of aerosol-generating substrate substantially through the centre of a cross-sectional face of the rod perpendicular to the rod length.

[0470] Example Ex79: The aerosol-generating system according to example Ex76 and any one of examples Ex77 or Ex78, wherein the pin or blade comprises a susceptor element and the inductor coil is arranged to inductively heat the pin or blade.

[0471] Example Ex80: The aerosol-generating system according to example Ex76 and any one of examples Ex72 to Ex79, wherein the aerosol-generating article comprises a susceptor element arranged within the rod of aerosol-generating substrate and the inductor coil of the aerosol-generating device is arranged to inductively heat the susceptor element.

[0472] Example Ex81: The aerosol-generating system according to any one of examples Ex72 to Ex80, wherein the heating element is located around the periphery of the device cavity, optionally wherein the heating element circumscribes the aerosol-generating article when the aerosol-generating article is at least party received in the device cavity, optionally wherein the heating element comprises a susceptor element, optionally wherein the inductor coil of the aerosol-generating device is arranged to inductively heat the susceptor element.

[0479] FIG. 1 shows a schematic cross-sectional view of an aerosol-generating article 10. The aerosol-generating article 10 has a substantially cylindrical shape along its length. The aerosol-generating article 10 comprises a rod of aerosol-generating substrate 12. The rod of aerosol-generating substrate 12 has a substantially cylindrical shape along its length, and comprises a gathered sheet of homogenised tobacco. The article further comprises a downstream section 17, located downstream of the rod of aerosol-generating substrate 12. The downstream section 17 comprises a first hollow tubular element 14, a second hollow tubular element 15, and a mouth-end filter 18. The mouth-end filter 18 is at a proximal (downstream) end of the article 10.

[0480] The downstream section 17 comprises an intermediate section 17a located in between the rod of aerosol-generating substrate 12 and the mouth-end filter 18. The intermediate section 17a comprises the first hollow tubular element 14 and the second hollow tubular element 15.

[0481] The aerosol-generating article 10 further comprises an upstream element 11 at a distal (upstream) end of the article 10. The upstream element 11 is a solid cylindrical plug element having a filled cross-section. The upstream element 11 comprises cellulose acetate. The RTD of the upstream element is 5.5 millimetres of water gauge. A longitudinal axis 7 extends centrally along a longitudinal direction of the aerosol-generating article 10. In this example, the length of the upstream element 11 is 5 millimetres. The upstream element 11, the rod of aerosol-generating substrate 12, the first hollow tubular element 14, the second hollow tubular element 15, and the mouth-end filter 18 are arranged end-to-end along the longitudinal axis 7.

[0482] The aerosol-generating article 10 comprises an aerosol-forming section 17b comprising the upstream element 11, the rod of aerosol-generating substrate 12 and the intermediate section 17a.

[0483] The upstream element 11, the rod of aerosol-generating substrate 12, the first hollow tubular element 14 and the second hollow tubular element 15 are circumscribed by a first wrapper 16. The first wrapper 16 does not circumscribe the mouth-end filter 18. That is, the first wrapper 16 only circumscribes the aerosol-forming section 17b. The first wrapper 16 extends from an upstream end of the article 10. The first wrapper 16 is made of paper.

[0484] The second hollow tubular element 15 and the mouth-end filter 18 are circumscribed by a second wrapper 19. The second wrapper 19 overlaps part of the first wrapper 16. The second wrapper 19 extends from a downstream end of the article 10.

[0485] The first wrapper 16 has a first wrapper length. In this example, the first wrapper length is 33 millimetres. The first wrapper length is 73 percent of the length of the article 10. The second wrapper 19 has a second wrapper length. In this example, the second wrapper length is 21 millimetres. The second wrapper length is 47 percent of the length of the article 10.

[0486] In this example, the length of overlap of the first wrapper 16 and second wrapper 19 in a direction parallel to the longitudinal axis 7 is equal to the length of the second hollow tubular element 15. That is, the length of overlap of the first wrapper 16 and second wrapper is 9 millimetres.

[0487] A downstream end of the second wrapper 19 is downstream of a downstream end of the first wrapper 16. An upstream end of the first wrapper 16 is upstream of an upstream end of the second wrapper 19.

[0488] The thickness of the first wrapper 16 is 41 micrometres. The grammage of the first wrapper 16 is 36 grams per square metre (gsm). The bulk of the first wrapper 16 is 1.14 cubic centimetres per gram. The thickness of the second wrapper 19 is 45 micrometres. The grammage of the second wrapper 19 is 39 grams per square metre (gsm). The bulk of the second wrapper 19 is 1.15 cubic centimetres per gram.

[0489] Each of the first wrapper 16 and the second wrapper 19 do not extend beyond the ends of the aerosol-generating article 10 in a direction parallel to the longitudinal axis 7.

[0490] Each of the first wrapper 16 and the second wrapper 19 form part of the outer surface of the aerosol-generating article 10. That is, along the longitudinal axis 7, either the first wrapper 16 or the second wrapper 19 is the radially outermost layer of the article 10. The second wrapper 19 has a printed element on the outer surface of the second wrapper 19, in this example the printed element is a pattern and colour.

[0491] It will be appreciated that, in addition to the first wrapper 16 and the second wrapper 19, one or more of the components, such as the upstream element 11, the rod of aerosol-generating substrate 12 and the mouth-end filter 18 may each be circumscribed by individual wrappers (not shown) which underlie at least one of the first wrapper 16 and the second wrapper 19.

[0492] The rod of aerosol-generating substrate 12 has a rod length parallel to the longitudinal axis 7 of the aerosol-generating article 10 and a rod width perpendicular to the longitudinal axis 7 of the aerosol-generating article 10. The rod width is substantially uniform along the rod length. In this example, the rod width is 7 millimetres. In this example, the rod length is 11 millimetres. The resistance to draw (RTD) of the rod of aerosol-generating substrate 12 is 13.6 millimetres of water gauge. The length of the aerosol-generating article 10 is 45 millimetres. The resistance to draw (RTD) of the aerosol-generating article 10 is 46 millimetres of water gauge.

[0493] The aerosol-generating article 10 further comprises a susceptor element 12a arranged within the rod of aerosol-generating substrate 12. The susceptor element 12a is configured to be heated when penetrated by a varying magnetic field. The length of the susceptor element 12a is approximately equal to the rod length. That is, the length of the susceptor element 12 a is 11 millimetres. The width of the susceptor element 12 a is 4 millimetres and the thickness of the susceptor element 12 a is 60 micrometres.

[0494] As mentioned above, the downstream section 17 comprises a mouth-end filter 18, a second hollow tubular element 15, and a first hollow tubular element 14. The downstream section 17 extends between the rod of aerosol-generating substrate 12 and the downstream end of the aerosol-generating article 10. The downstream section 17 has a length of 29 millimetres. The second hollow tubular element 15 is downstream of the first hollow tubular element 14. The first hollow tubular element 14 is a hollow acetate tube. The second hollow tubular element 15 is a hollow acetate tube. The first hollow tubular element 14 abuts the downstream end of the rod of aerosol-generating substrate 12. The length of the first hollow tubular element 14 is 8 millimetres. The length of the second hollow tubular element 15 is 9 millimetres.

[0495] The first hollow tubular element 14 comprises a lumen. The lumen of the first hollow tubular element 14 has a substantially circular cross-sectional shape. The second hollow tubular element 15 comprises a lumen. The lumen of the second hollow tubular element 15 has a substantially circular cross-sectional shape. The width of the lumen (inner width) of the second hollow tubular element 15 is larger than the width of the lumen (inner width) of the first hollow tubular element 14. The wall thickness of the second hollow tubular element 15 is smaller than the wall thickness of the first hollow tubular element 14. The second hollow tubular element 15 may be referred to as a fine hollow acetate tube (FHAT). The wall thickness of the second hollow tubular element 15 is 1.05 millimetres. The wall thickness of the second hollow tubular element 14 is 1.9 millimetres. The width of each of the first hollow tubular element 14 and the second hollow tubular element 15 is 7.1 millimetres. The combined RTD of the first hollow tubular element 14 and the second hollow tubular element 15 is about 0 millimetres of water gauge.

[0496] The second hollow tubular element 15 comprises a ventilation zone at a location along the second hollow tubular element 15. It will be appreciated that the ventilation zone could alternatively or in addition be provided at a location along the first hollow tubular element 14. The ventilation zone comprises one or more rows of ventilation holes 13 arranged circumferentially around the second hollow tubular element 15 in a cross-section that is substantially perpendicular to the longitudinal axis 7 of the aerosol-generating article 10. The ventilation holes 13 are perforations through the wall of the second hollow tubular element 15. A ventilation level of the aerosol-generating article 10 is about 50 percent. Each circumferential row of ventilation holes 13 comprises about 11 holes. The ventilation holes 13 extend through both the first wrapper 16 and the second wrapper 19 in a direction perpendicular to the longitudinal axis 7. The distance of the ventilation holes 13 from the downstream end of the article 10 is 18 millimetres.

[0497] The mouth-end filter 18 is located at a downstream end of the aerosol-generating article 10. The mouth-end filter 18 abuts the downstream end of the second hollow tubular element 15. The mouth-end filter 18 comprises a low-density, cellulose acetate filter segment. The RTD of the mouth-end filter 18 is about 18 millimetres of water gauge. The length of the mouth-end filter 18 is 12 millimetres. The width of the mouth-end filter 18 is 7.2 millimetres.

[0498] FIG. 2 shows a schematic cross-sectional view of an aerosol-generating article 20. The aerosol-generating article 20 has a substantially cylindrical shape along its length. The aerosol-generating article 20 comprises a rod of aerosol-generating substrate 22 at a distal end of the article 20. The rod of aerosol-generating substrate 22 has a substantially cylindrical shape along its length, and comprises a gathered sheet of homogenised tobacco. The article further comprises a downstream section 27, located downstream of the rod of aerosol-generating substrate 22. The downstream section 27 comprises a hollow tubular element 24, a PLA (poly lactic acid) plug 25, and a mouth end filter 28. The mouth-end filter 28 is at a proximal end of the article 20. A longitudinal axis 7 extends centrally along a longitudinal direction of the aerosol-generating article 20. The rod of aerosol-generating substrate 22, the hollow tubular element 24, the PLA plug 25, and the mouth-end filter 28 are arranged end-to-end along the longitudinal axis 7.

[0499] The downstream section 27 comprises an intermediate section 27a located in between the rod of aerosol-generating substrate 22 and the mouth-end filter 28. The intermediate section 27a comprises the hollow tubular element 24 and the PLA plug 25.

[0500] The aerosol-generating article 20 comprises an aerosol-forming section 27b comprising the rod of aerosol-generating substrate 22 and the intermediate section 27a.

[0501] The rod of aerosol-generating substrate 22, the hollow tubular element 24, the PLA plug 25, and the mouth-end filter 28 are circumscribed by a first wrapper 26. The first wrapper 26 extends along the entire length of the aerosol-generating article 20. It will be appreciated that in other embodiments the first wrapper 26 may not extend along the entire length of the aerosol-generating article 20 and, for example, may not circumscribe the mouth-end filter 28. The first wrapper 26 is made of paper.

[0502] The PLA plug 25 and the mouth-end filter 28 are circumscribed by a second wrapper 29. The second wrapper 29 overlaps part of the first wrapper 26. The second wrapper 29 extends from a downstream end of the article 20.

[0503] The first wrapper 26 has a first wrapper length. In this example, the first wrapper length is equal to the length of the aerosol-generating article 20. That is, the first wrapper length is 45 micrometres. The second wrapper 29 has a second wrapper length. In this example, the second wrapper length is 20 millimetres. The second wrapper length is 44 percent of the length of the article 20.

[0504] In this example, the length of overlap of the first wrapper 26 and second wrapper 29 in a direction parallel to a longitudinal direction of the article is equal to the second wrapper length.

[0505] A downstream end of the second wrapper 29 is at the same position as a downstream end of the first wrapper 26 along the longitudinal axis 7. An upstream end of the first wrapper 26 is upstream of an upstream end of the second wrapper 29.

[0506] The thickness of the first wrapper 26 is 41 micrometres. The grammage of the first wrapper 26 is 36 grams per square metre (gsm). The bulk of the first wrapper 26 is 1.14 cubic centimetres per gram. The thickness of the second wrapper 29 is 45 micrometres. The grammage of the second wrapper 29 is 39 grams per square metre (gsm). The bulk of the second wrapper 29 is 1.15 cubic centimetres per gram.

[0507] Each of the first wrapper 26 and the second wrapper 29 do not extend beyond the ends of the aerosol-generating article 20 in a direction parallel to the longitudinal axis 7.

[0508] Each of the first wrapper 26 and the second wrapper 29 form part of the outer surface of the aerosol-generating article 20. That is, along the longitudinal axis 7, either the first wrapper 26 or the second wrapper 29 is the radially outermost layer of the article 10. The second wrapper 29 has a printed element on the outer surface of the second wrapper 19, in this example the printed element is a pattern and colour.

[0509] The rod of aerosol-generating substrate 22 has a rod length parallel to the longitudinal axis 7 of the aerosol-generating article 20. The rod of aerosol-generating substrate 22 has a rod width perpendicular to the longitudinal axis 7 of the aerosol-generating article 20. The rod width is substantially uniform along the rod length. In this example, the rod width is 7.2 millimetres. In this example, the rod length is 12 millimetres. The length of the aerosol-generating article 20 is 45 millimetres.

[0510] As mentioned above, the downstream section 22 comprises a mouth-end filter 28, PLA (poly lactic acid) plug 25, and a hollow tubular element 24. The downstream section 27 extends between the rod of aerosol-generating substrate 21 and the downstream end of the aerosol-generating article 20. The downstream section 27 has a length of 33 millimetres.

[0511] The PLA plug 25 is downstream of the hollow tubular element 24. The hollow tubular element 24 is a hollow acetate tube. The hollow tubular element 24 abuts the downstream end of the rod of aerosol-generating substrate 22. The length of the hollow tubular element 24 is 8 millimetres. The length of the PLA plug 25 is 18 millimetres. The hollow tubular element 24 comprises a lumen. The lumen of the hollow tubular element 24 has a substantially circular cross-sectional shape. The wall thickness of the hollow tubular element 24 is 0.25 millimetres. The external diameter of the hollow tubular element 24 is 7.2 millimetres. The RTD of the hollow tubular element 24 is about 0 millimetres of water gauge.

[0512] The mouth-end filter 28 is located at a downstream end of the aerosol-generating article 10. The mouth-end filter 28 abuts the downstream end of the PLA plug 25. The mouth-end filter 28 comprises a low-density, cellulose acetate filter segment. The RTD of the mouth-end filter 28 is about 8 millimetres of water gauge. The length of the mouth-end filter 28 is about 7 millimetres.

[0513] FIG. 3 shows a schematic cross-sectional view of an aerosol-generating article 30. The aerosol-generating article 30 has a substantially circular cross-sectional shape along its length. The aerosol-generating article 30 comprises a rod of aerosol-generating substrate 32. The rod of aerosol-generating substrate 32 has a substantially cylindrical shape along its length, and comprises a gathered, crimped sheet of homogenised tobacco.

[0514] The article 30 further comprises a downstream section 37, located downstream of the rod of aerosol-generating substrate 32. The downstream section 37 comprises a mouth end filter 38. The mouth-end filter 38 is at a proximal end of the article 30. A longitudinal axis 7 extends centrally along a longitudinal direction of the aerosol-generating article 30. The downstream section 37 also comprises a hollow tubular element 34 comprising a tubular body defining a cavity 34b extending from an upstream end of the tubular body to a downstream end of the tubular body. The hollow tubular element (hereinafter referred to as a flanged tube 34) also comprises a folded end portion forming an upstream end wall 34c at the upstream end of the tubular body. The rod of aerosol-generating substrate 32, the flanged tube 34 and the mouth-end filter 38 are arranged end-to-end along the longitudinal axis 7.

[0515] The downstream section 37 comprises an intermediate section 37a located in between the rod of aerosol-generating substrate 32 and the mouth-end filter 38. The intermediate section 37a comprises the flanged tube 34.

[0516] The aerosol-generating article 30 further comprises an upstream element 31 at a distal end of the article 30. The upstream element 31 comprises a tubular segment. In this example, the length of the upstream element 31 is 5 millimetres.

[0517] The aerosol-generating article 30 comprises an aerosol-forming section 37b comprising the upstream element 31, the rod of aerosol-generating substrate 32 and the intermediate section 37a.

[0518] The upstream element 31, the rod of aerosol-generating substrate 32 and the flanged tube 34 are circumscribed by a first wrapper 36. The first wrapper 36 does not circumscribe the mouth-end filter 38. That is, the first wrapper 36 only circumscribes the aerosol-forming section 37b. The first wrapper 36 extends from an upstream end of the article 30. The first wrapper 36 is made of paper.

[0519] A part of the flanged tube 34 and an entire length of the mouth-end filter 18 are circumscribed by a second wrapper 39. The second wrapper 39 overlaps part of the first wrapper 36. The second wrapper 19 extends from a downstream end of the article 30.

[0520] The first wrapper 36 has a first wrapper length. In this example, the first wrapper length is 38 millimetres. The first wrapper length is 84 percent of the length of the article 30. The second wrapper 39 has a second wrapper length. In this example, the second wrapper length is 26 millimetres. The second wrapper length is 58 percent of the length of the article 30.

[0521] In this example, the length of overlap of the first wrapper 36 and second wrapper 39 in a direction parallel to a longitudinal direction of the article is 19 millimetres.

[0522] A downstream end of the second wrapper 39 is downstream of a downstream end of the first wrapper 36. An upstream end of the first wrapper 36 is upstream of an upstream end of the second wrapper 39.

[0523] The thickness of the first wrapper 36 is 41 micrometres. The grammage of the first wrapper 36 is 36 grams per square metre (gsm). The bulk of the first wrapper 36 is 1.14 cubic centimetres per gram. The thickness of the second wrapper 39 is 66 micrometres. The grammage of the second wrapper 39 is 58 grams per square metre (gsm). The bulk of the second wrapper 39 is 1.14 cubic centimetres per gram.

[0524] Each of the first wrapper 36 and the second wrapper 39 do not extend beyond the ends of the aerosol-generating article 30 in a direction parallel to the longitudinal axis 7.

[0525] Each of the first wrapper 36 and the second wrapper 39 form part of the outer surface of the aerosol-generating article 30. That is, along the longitudinal axis 7, either the first wrapper 36 or the second wrapper 39 is the radially outermost layer of the article 30. The second wrapper 39 has a printed element on the outer surface of the second wrapper 39, in this example the printed element is a pattern and colour.

[0526] The rod of aerosol-generating substrate 32 has a rod length parallel to the longitudinal axis 7 of the aerosol-generating article 30. The rod of aerosol-generating substrate 32 has a rod width perpendicular to the longitudinal axis 7 of the aerosol-generating article 30. The rod width is substantially uniform along the rod length. In this example, the rod width is 7.1 millimetres. In this example, the rod length 28 is 12 millimetres. The length of the aerosol-generating article is 45 millimetres.

[0527] As mentioned above, the downstream section 37 comprises a mouth-end filter 38 and a flanged tube 34. The downstream section 37 extends between the rod of aerosol-generating substrate 32 and the downstream end of the aerosol-generating article 30. The downstream section 37 has a length of 28 millimetres.

[0528] The flanged tube 34 abuts the downstream end of the rod of aerosol-generating substrate 32. The upstream end wall 34c of the flanged tube 34 delimits an opening 34d, which permits airflow between the cavity 34b and the exterior of the flanged tube 34. In particular, aerosol may flow from the rod of aerosol-generating substrate 32 through the opening 34d into the cavity 34b. The cavity 34b of the flanged tube 34 is substantially empty, and so substantially unrestricted airflow is enabled along the cavity 34b. Consequently, the RTD of the flanged tube 34 can be localised at a specific longitudinal position of the flanged tube 34—namely, at the upstream end wall 34c—and can be controlled through the chosen configuration of the upstream end wall 34c and its corresponding opening 34d. In this example, the RTD of the flanged tube 34 (which is essentially the RTD of the upstream end wall 34c) is about 10 millimetres of water gauge.

[0529] The upstream end wall 34c extends substantially transverse to the longitudinal axis 7 of the aerosol-generating article 30. The opening 34d is the only opening in the upstream end wall 34c and the opening 34d is positioned in a generally radially central position of the flanged tube 34. Consequently, the upstream end wall 34c is generally annular shaped. The combination of the upstream end wall 34c and its corresponding opening 34d provide an effective barrier arrangement which may restrict movement of the rod of aerosol-generating substrate 32, whilst also enabling aerosol to flow from the rod of aerosol-generating substrate 32 through the opening 34 d into the cavity 34 b. The flanged tube 34 has a length of about 21 millimetres, an external width of about 7.1 millimetres. The flanged tube 34 is formed from a paper material, such as paper, paperboard or cardboard. In this example, the cavity 34b of the flanged tube 34 has a substantially circular cross-sectional shape.

[0530] The flanged tube 34 comprises a ventilation zone at a location along the flanged tube 34. The ventilation zone comprises one or more rows of ventilation holes 33 arranged circumferentially around the hollow tube in a cross-section that is substantially perpendicular to the longitudinal axis 7 of the aerosol-generating article 30. The ventilation holes 33 are perforations through the wall of the flanged tube 34. A ventilation level of the aerosol-generating article 30 is about 75 percent. Each circumferential row of ventilation holes 33 comprises from 8 to 30 holes. The ventilation holes 33 extend through both the first wrapper 36 and the second wrapper 39 in a direction perpendicular to the longitudinal axis 7. The distance of the ventilation holes 33 from the downstream end of the article 30 is 16 millimetres.

[0531] The mouth-end filter 38 is located at a downstream end of the aerosol-generating article 30. The mouth-end filter 38 abuts the flanged tube 34. The mouth-end filter 38 comprises a low-density, cellulose acetate filter segment. The RTD of the mouth-end filter 38 is about 8 millimetres of water gauge. The length of the mouth-end filter 38 is about 7 millimetres.

[0532] FIG. 4 shows a schematic cross-sectional view of a portion of an aerosol-generating system 1000 comprising the aerosol-generating article 10 of FIG. 1 and an aerosol-generating device 100.

[0533] In this embodiment, the aerosol-generating article 10 comprises a susceptor element 12a arranged within the rod of aerosol-generating substrate 12. The susceptor element 12a is configured to be heated when penetrated by a varying magnetic field.

[0534] The aerosol-generating device 100 further comprises an inductor coil 126 which circumscribes the device cavity 121, and surrounds the susceptor element 12a. The inductor coil 126 is arranged to generate a varying magnetic field in the device cavity 121, which penetrates the susceptor element 12a to inductively heat the susceptor element 12a.

[0535] The device cavity 121 is configured to receive at least a part of the aerosol-generating article 10. The distal end of the device cavity 121 has a closed end. The proximal end of the device cavity 121 has an open end. The aerosol-generating article 10 is insertable into the device cavity 121 via the open end of the device cavity 221.

[0536] In use, the user inserts the aerosol-generating article 10 into the device cavity 121 of the aerosol-generating device 100.

[0537] The aerosol-generating device 100 further comprises a power supply (not shown) and electronics (not shown) that are arranged to supply power to the inductor coil 226 to generate a varying magnetic field in the device cavity 121 to inductively heat the susceptor element 12a.

[0538] The susceptor element 12a heats the rod of aerosol-generating substrate 12 when the aerosol-generating article 10 is received in the device cavity 121. Such actuation of the inductor coil 126 may be manually operated or may occur automatically in response to a user drawing on the aerosol-generating article 10 when the aerosol-generating article 10 is inserted into the device cavity 121.

[0539] The entire length of the rod of aerosol-generating substrate 12 is received in the device cavity 121. The device cavity 121 has a substantially circular cross-sectional shape. The device cavity 121 has substantially the same cross-sectional shape as the rod of aerosol-generating substrate 12. The ventilation holes 13 of the second hollow tubular element 15 are not received in the device cavity 121.

[0540] During use, the inductor coil 126 is controlled to heat the susceptor element 12a within a defined operating temperature range, below a maximum operating temperature. The operating temperature of the susceptor element 12a is about 350 degrees Celsius.

[0541] FIG. 5 shows a schematic cross-sectional view of a portion of an aerosol-generating system 2000 comprising the aerosol-generating article 20 of FIG. 2 and an aerosol-generating device 200.

[0542] The aerosol-generating device 200 comprising a heating element in the form of a blade 220. The blade 220 is a resistive heating element. The blade 220 is mounted within a device cavity 221. The device cavity 221 is configured to receive at least a part of the aerosol-generating article 20. The distal end of the device cavity 221 has a closed end. The proximal end of the device cavity 221 has an open end. The aerosol-generating article 20 is insertable into the device cavity 221 via the open end of the device cavity 221.

[0543] In use, the user inserts the aerosol-generating article 20 into the device cavity 221 of the aerosol-generating device 200, such that the blade 220 is inserted into the rod of aerosol-generating substrate 22 of the aerosol-generating article 20. The blade 220 is tapered towards a tip at the end of the blade, such that the tip of the blade 220 is configured to penetrate the rod of aerosol-generating substrate 22.

[0544] The aerosol-generating device 200 further comprises a power supply (not shown) and electronics (not shown) that allow the blade 220 to be actuated to heat the rod of aerosol-generating substrate 22 when the aerosol-generating article 20 is received in the device cavity 221. Such actuation may be manually operated or may occur automatically in response to a user drawing on the aerosol-generating article 20 when the aerosol-generating article 20 is inserted into the device cavity 221.

[0545] As shown in FIG. 5, a portion of the aerosol-generating article 20 is received in the device cavity 221 of the aerosol-generating device 20, and the blade 220 penetrates the rod of aerosol-generating substrate 22 along the longitudinal axis 7 of the aerosol-generating article. The entire length of the rod of aerosol-generating substrate 22 is received in the device cavity 221. The device cavity 221 has a substantially circular cross-sectional shape. The device cavity 221 has substantially the same cross-sectional shape as the rod of aerosol-generating substrate 22

[0546] During use, the blade 220 is controlled to operate within a defined operating temperature range, below a maximum operating temperature. The operating temperature range of the blade 220 is about 350 degrees Celsius.