Packaging container

[0002] This application is a 371 National Stage Application of International Patent Application No. PCT/CH96/00409, filed on Nov. 18, 1996, that has priority benefit of Swiss Patent Application No. 03373/95, filed on Nov. 28, 1995.

[0003] The invention relates to a packaging container made from a cold formed composite, a process for its manufacture and the use thereof.

[0004] It is known to employ packaging means for the purpose of protecting e.g. pharmaceutical products, medical aids, diagnostic aids and other products which are sensitive to light, gas and/or moisture. Particularly suitable types of packaging are shaped forms of packaging made by stretching, stretch drawing, or deepening. In order to make packaging impermeable to light, gas and vapours, the material from which the packaging is made must have a barrier layer. A particularly suitable barrier layer may be e.g. a metal foil or metal strip. In practice, as the metal foil alone is not able to fulfil all of the requirements made of a packaging material, further layers—in particular layers of plastic—are applied to one or both sides of the metal foil. Such layers may e.g. be extrusion bonded or layers in the form of films of thermoplastics attached by means of adhesive agents. With such multi-layer laminates readily formable packaging materials are produced that can be processed further e.g. into the base parts of blister packs or other forms of packaging.

[0005] It has now been found that none of the laminates which have found use in practice exhibit sufficient flatness and/or stiffness for further processing after being shaped into packaging forms or parts such as the base part of packaging. It has also been found that laminates which exhibit inadequate flatness and/or stiffness, after shaping into parts for packaging such as base parts for blister packs or push-through packs, result in shaped parts that also exhibit inadequate flatness and/or stiffness. By flatness is meant here that the laminate exhibits a tendency to roll or parts formed out of the laminate are domed and e.g. do not lie uniformly on a flat surface, but instead are curved in a wavy, arched or dome-like manner.

[0006] The object of the present invention is therefore to propose a packaging container which is manufactured out of a composite and the packaging container exhibits a high degree of flatness and/or stiffness.

[0007] That objective is achieved by way of the invention in that the composite from which the packaging container or parts thereof is/are manufactured exhibits a layered structure containing:

[0008] a) a plastic film having a thickness of 10 μm to 250 μm,

[0009] b) a biaxially or uniaxially stretched film of the polyvinylchloride, polyolefin, polyamide or polyester type having a thickness of 10 to 100 μm, or a biaxially or uniaxially stretched plastic laminate of two films of the polyvinylchloride, polyolefin, polyamide or polyester type each having a thickness of 10 to 50 μm,

[0010] c) a metal foil having a thickness of 20 to 200 μm,

[0011] and

[0012] a₁) a plastic film having a thickness of 10 to 250 μm,

[0013] and the packaging container exhibits a high degree of flatness and/or stiffness.

[0014] Usefully, according to the present invention packaging containers, or parts thereof, exhibit a laminate which features between layer

[0015] c), the metal foil having a thickness of 20 to 200 μm,

[0016] and

[0017] a₁) the plastic film having a thickness of 10 to 250 μm,

[0018] a layer

[0019] b₁) a biaxially or uniaxially stretched film of the polyvinylchloride, polyolefin, polyamide or polyester type having a thickness of 10 to 100 μm, or a biaxially or uniaxially stretched plastic laminate of two films of the polyvinylchloride, polyolefin, polyamide or polyester type each having a thickness of 10 to 50 μm.

[0020] In practice layer a) is on the side of the container facing outwards, while a₁) forms the side of the container facing inwards i.e. the inner face.

[0021] The plastic films a) and a₁) may e.g. be of thermoplastics such as halogen-containing polymers, polyesters, polyolefins, polyamides or acrylnitrile copolymers. The plastic films a) and a₁) may preferably be non-stretched or if desired uniaxially or biaxially stretched.

[0022] The layers b) and b₁) are biaxially or uniaxially stretched plastic films. Usefully, the plastic films b) and b₁) are of the uniaxially stretched polyvinylchloride or uniaxially or biaxially stretched polyamide, polypropylene and polyester film type or laminates.

[0023] Examples of plastics a), b), and b₁) based on halogen-containing polymers are polymers of vinylchloride (PVC) and vinyl plastics, containing vinylchloride units in their structure, such as copolymers of vinylchloride and vinylesters of aliphatic acids, copolymers of vinylchloride and esters of acrylic or methacrylic acids or acrylnitrile, copolymers of diene compounds and unsaturated dicarboxyl acids or their anhydrides, copolymers of vinylchloride and vinylchloride with unsaturated aldehydes, ketones etc. or polymers and copolymers of vinylidenchloride with vinylchloride or other polymerisable compounds. The vinyl-based thermoplastics may also be made soft in a conventional manner by means of primary or secondary softeners. Films out of PVC may in some cases also be uniaxially (oPVC) or biaxially stretched.

[0024] If the plastic films a), b), a₁) and b₁) are of polyesters (PET-films), then examples of the polyesters are polyalkylene-terephthalate or polyalkylene-isophthalate with alkylene groups or radicals with 2 to 10 carbon atoms or alkylene groups with 2 to 10 C atoms interrupted by at least one —O— atom, such as e.g. polyethylene-terephthalate, polypropylene-terephthalate, polybutylene-terephthalate (polytetramethylene-terephthalate), polydecamethylene-terephthalate, poly 1.4-cyclohexyldimethylol-terephthalate or polyethylene-2.6-naphthalene-dicarboxylate or mixed polymers of polyalkylene-terephthalate and polyalkylene-isophthalate, where the fraction of isophthalate amount e.g. to 1 to 10 mol. %, mixed polymers and terpolymers, also block polymers and grafted modifications of the above mentioned materials. Preferred are polyethylene-terephthalate films. Other useful polyesters are known in the field by the abbreviation PEN.

[0025] Other polyesters are copolymers of terephthalic acid and a further polycarboxyl acid with at least one glycol. Useful thereby are the copolymers of terephthalic acid, ethyleneglycol and an additional glycol. Preferred are glycol-modified polysters known in the field as PETG.

[0026] Useful polyesters are polyalkylene-terephthalates with alkylene groups or radicals with 2 to 10 carbon atoms and polyalkylene-terephthalates with alkylene groups or radicals with 2 to 10 carbon atoms which are interrupted by one or two —O— atoms.

[0027] Further preferred polyesters are polyalkylene-terephthalates with alkylene groups or radicals with 2 to 4 carbon atoms and, very highly preferred, polyethyleneterephthalates belonging to which are also A-PET, PETP and the above mentioned PETG or G-PET.

[0028] Examples of polyolefins for plastic films a), b), a₁) and/or b₁) are polyethylenes (PE) e.g. high density polyethylene (HDPE, density larger than 0.944 g/cm₃, medium density polyethylene (MDPE, density 0.926-0.940 g/cm³), linear polyethylene of medium density (LMDPE, density 0.926.0.940 g/cm³), low density polyethylene (LDPE, density 0.910-0.925 g/cm³) and linear low density polyethylene (LLDPE, density 0.916-0.925 g/cm³), for example as non oriented (PE film) or uniaxially or biaxially oriented films, (oPE film), polypropylenes (PP), such as axially or biaxially oriented polypropylene (oPP film) or cast polypropylene (cPP film), amorphous or crystalline polypropylene or mixtures thereof, ataktic or isotaktic polypropylene or mixtures thereof, poly-1-butene, poly-3-methylbutene, poly-4-methyl-pententene and copolymers thereof, then polyethylene with vinylacetate, vinylalcohol, acrylic acid etc. such as e.g. ionomeric resins, such as copolymers of ethylene with 11% acrylic acid, methacrylic acid, acrylic esters, tetrafluorethylene or polypropylene, also statistical copolymers, block polymers or olefin polymer-elastomer mixtures. Preferred are high density polyethylenes and polypropylenes, also ionomers, e.g. known under the trade names Surlyn, and ethylene-acrylic acid copolymers (EAA).

[0029] If the plastic films a), b), a₁) and b₁) are polyamide films (PA) then e.g. the following belong to the polyamides viz, polyamide 6, a homo-polymer of ε-caprolactam (polycaprolactam); polyamide 11, polyamide 12, a homo-polymer of ω-laurinlactam (polylaurinlactam); polyamide 6.6, a homo-polycondensate of hexamethylenediamine and adipinic acid (poly-hexa-methylene-adi-amide); polyamide 6.10, a homo-polycondensate of hexa-methylene-diamine and sebacinic acid (poly-hexa-methylene-sebacamide); polyamide 6.12, a homo-polycondensate of hexa-methylene-diamine and dodecandic acid (poly-hexa-methylene-dode-canamide) or polyamide 6-3-T, a homo-polycondensate of trimethyl-hexa-methylene-diamine and terephthalic acid (poly-trimethyl-hexa-methylene-terephthalic-amide), and mixtures thereof. Films of polyamide may in some cases be uniaxially or biaxially stretched (oPA).

[0030] If the plastic films a), b), a₁) and b₁) are of acrylnitrile-copolymers, then e.g. the following are included in this group viz, copolymers of acrylnitrile or methacrylnitrile with acrylic acid esters, vinyl-carboxylate esters, vinyl halides, aromatic vinyl compounds or unsaturated carboxylic acid and diene and in particular acrylnitrile-methylacrylate copolymers (e.g. known under the trade name “BAREX”.

[0031] If the above mentioned plastics are extrudable, then they may also be applied to the laminate in the form of an extruded layer.

[0032] Layer c), a metal foil, has a thickness of 20 to 200 μm, a thickness of 20 to 150 μm being useful and 30 to 60 μm being preferred. The metal foil may be of iron, steel, nickel, copper, tin, bronze, brass, aluminum etc. The metal foil is advantageously of aluminium having a purity of 99.95% to 97% (wt. %), the remainder being the unavoidable accompanying impurities or alloying elements. Examples of alloys are those having aluminium as the main constituent and the alloying element Fe; Si; Mg; Ti and/or Cu.

[0033] The layers a), and a₁), i.e. the uniaxially or biaxially stretched films of plastics of the polyvinylchloride, polyolefin, polyamide or polytethyleneterephthalate type may usefully have a thickness of 10 to 80 μm and advantageously a thickness of 12 to 50 μm. For plastic laminates the stated dimensions refer to the total thickness.

[0034] In order to join the described layers to each other i.e. a) to b), b) to c), d) to a₁) or c to b₁) and b₁) to a₁), these may be adhered to each other by adhesives such as laminate coatings, laminate adhesives and/or adhesive agents and if desired by precoating with bonding materials, by hot calandering, by extrusion coating, by co-extrusion coating or by means of a combination of these methods to form composites, laminates or films.

[0035] Suitable laminate adhesives may contain solvents, be solvent-free, or may be aqueous acrylic adhesives or polyurethane adhesive systems. Adhesives which harden under the influence of electromagnetic rays (e.g. UV; electron beams) may, however, also be employed.

[0036] Preferred are polyurethane-based laminate adhesives.

[0037] For example, di-isocryanate or aliphatic polyesters may be employed as bonding agents. As a rule these bonding agents are only employed between the outwards facing layers.

[0038] Suitable coatings are e.g. those based on acrylates, epoxy resins, melaminic resins, uric resins, polyurethanes, cellulose nitrate, polyesters and mixtures thereof. The coatings may e.g. be solvent-based or water-based, or may be single, two or more component systems. The coatings are hardenable e.g. by drying, by application of heat, chemical means and/or by radiation (UV; electron-beams; IR).

[0039] Usefully, the thickness of coating materials employed between the individual layers of the composite for the packaging container according to the invention is 0.1 μm to 12 μm.

[0040] The laminate adhesive may e.g. be employed in amounts of 1 to 10 g/m², preferably from 2 to 8 g/m²and in particular in an amount of 3 to 6 g/m². The laminate adhesives may also be employed in such amounts that the layers have a thickness of at least 0.1 μm and at most 12 μm.

[0041] The metal surface may by appropriate pre-treatment (e.g. brushing, chromate treatment, ionising, ozone, corona, flame or plasma treatment) exhibit better bonding for the adhesive or coating or for an extruded layer. To assist and improve the bonding of the coatings, bonding agents or laminate adhesives between the plastic films or extruded layers, it is often useful to provide the films on the sides facing the adhesive or the bonding of extruded layers with adequate surface tension. Increasing the surface tension may be effected preferably by an ionising, ozone, plasma, flame or corona pre-treatment.

[0042] The bonding of the individual layers of the laminate may also be obtained by extrusion laminating or hot calandering. The packaging containers may exhibit on their inner side i.e. on the side facing the contents, in some cases also on their outer side, a sealing layer such as a sealing film or sealing coating. The sealing films or sealing coatings may e.g. contain or be of polyolefins. the sealing layer makes it possible to apply a lid to the container according to the invention. Such lids may e.g. be lid foils, which are sealed to the shoulder of the container. Suitable lid foils may contain a metal foil such as an aluminium foil and, plastic films and/or coatings may be applied to one or both sides of the metal foil. On at least one side of the lidding foil there may be an outermost layer in the form of a sealing layer via which the lidding foil may be joined to the packaging container.

[0043] On the inner side and/or outer side or directed towards the inner and/or outer side, in each case with reference to the container according to the invention, may be the composite coating and/or printed pattern.

[0044] For example, the outer lying and/or the inner lying film of the laminate may exhibit a reversed image pattern on its inner side i.e. facing the composite. A reversed image pattern is particularly suitable for transparent and translucent films.

[0045] It is also possible to provide the outer lying and/or the inner lying film with a printed pattern and as required to cover the pattern with a coating. The outer and/or the inner lying side of the composite may also be provided with a coating, whereby as required the coating may also be printed on and/or patterned on the packaging line e.g. by means of UV, solvent or by laser or electron beams.

[0046] It is also possible to provide coating layers—which may also be coloured—between the other layers than the outer and inner layers and the next innermost layer. The films employed or the extruded layers may be transparent, translucent or opaque and may be clear or may be wholly or partially coloured.

[0047] Typical examples of packaging container according to the invention are laminated having a layer c) of aluminium foil or thin strip of thickness 20 to 150 μm and a layer b) in the form of a biaxially or uniaxially stretched film or a composite of two films of the polyvinylchloride, polypropylene, polyamide or polyester type having a thickness of 10 to 100 μm, whereby the layer b) covers one of the two surfaces of layer c). Both layers b) and c) are to advantage a PVC film with a thickness of 30 to 100 μm or a PET film of thickness 12 to 200 μm or a PE film of thickness 15 to 200 μm or a cPP film of thickness 20 to 200 μm or a PP film of thickness 30 to 60 μm. On the free side of layer c) of this part of a composite are further layers described below.

[0048] In a first specific embodiment the above mentioned partial composite may exhibit on the still free side of layer c) the layer a₁), preferably a PVC film of thickness 30 to 150 μm, a PET film of thickness 12 to 200 μm, a PE film of thickness 30 to 60 μm, a PP film of thickness 30 to 60 μm, a cPP film of thickness 20 to 200 μm, an ionomer layer with ethylene acrylic acid (EAA), e.g. a Surlyn layer of 10 to 100 g/m²(ca. 11 to 110 μm), or an extruded polyolefin layer of thickness 20 to 200 μm.

[0049] In a second specific embodiment the above mentioned partial composite may have applied to its still free layer c) e.g. a layer b1), an oPA film of thickness 15 to 25 μm or a PET film, in particular a PEN film, of thickness 12 to 50 μm or an oPVC film of thickness 40 to 100 μm and on top of a layer of bonding agent the layer a1), a PE film of thickness 15 to 100 μm or a PP film of thickness 30 to 60 μm or a cPP film of thickness 20 to 100 μm or a PET film of thickness 12 to 200 μm or a PVC film of thickness 30 to 150 μm may be applied.

[0050] Preferred examples of packaging containers according to the invention exhibit composites with a layer structure containing

[0051] or as further examples:

[0052] where the numbers are the thickness of the layers in μm and PVC stands for polyvinylchloride, oPVC for uniaxially oriented polyvinylchloride, PP for polypropylene, PET for polyethylene-terephthalate, PE for polyethylene, oPA for oriented polyamide, PEN for polyester of the PEN type, Al for aluminium foil, oPP for oriented polypropylene and PP for polypropylene.

[0053] Typical, practical examples are described in the following. In each case the thickness of the bonding layers is from 0.1 to 10.0 μm.

[0054] The packaging containers according to the present invention are manufactured by cold forming which includes e.g. the methods of stretch drawing or deep drawing or a combined process of deep and stretch drawing. The temperature of the tool used in the process may be from 30 to 150° C., usefully from 40 to 100° C. The drawing ratios achieved in the forming process are from 2 to 4, preferably 2.5 to 3.5 (breadth/height).

[0055] By packaging containers is meant cold formed base parts or lid parts or base and lid parts. The base part or the lid part may be shaped by cold forming and a lidding foil or a base foil may correspondingly form the closure of the container. Both the base and the lid part may be formed by cold forming, whereby the recesses formed in the base and lid parts usefully lie one on top of the other. The packaging containers may exhibit one or more e.g. 2 to 200, usefully 5 to 50 recesses, whereby each recess is usefully surrounded by a shoulder and the shoulders form a flat shoulder area. The recesses usually formed out of the surface may all be the same or different. A packaging container according to the invention may e.g. represent a base part of a shaped form of packaging such as a menu dish e.g. for human or animal foodstuffs, a push-through pack or blister pack, such as a blister pack for pharmaceuticals or a blister pack to accommodate preparations for further use in medical equipment, and other products that have to be protected. The shaped base part or lid part may be covered with a covering material such as foil or laminate acting as lidding material, in particular closing the shaped packaging container at the shoulder area. Preferred are lidding materials that can be penetrated by application of pressure. Particularly suitable lidding materials are aluminium foils or composites containing aluminium foil or plastic films that have been rendered brittle by fillers. Usefully, the lidding foils bear a sealable layer on at least one side. Suitable for closing purposes (sealing) are all known methods (hot sealing, ultrasonics, induction heating, high frequency heating). The packaging container is usefully joined to the lidding material via whole surface or partial sealing in the shoulder region. The recesses are surrounded by shoulders which form the shoulder areas, and each recess may be tightly sealed by the sealing joint in the region of the shoulders at each recess. Such a closed packaging container may be opened e.g. by cutting open or peeling away the lidding material, or the lid may be a fastening or the lidding material may be torn open by pressing against the contents. In some cases the plane material may also represent the base and the lid the shaped packaging container. Further, both the lid and the base may be manufactured from the composite according to the invention and form a packaging container according to the invention.

[0056] Of particular interest are packaging containers according to the invention featuring a plurality of shaped recesses in one of the described composites where in plan view the base part exhibits a round shape and the recesses are arranged in a concentric manner e.g. in one or two rings. The base part is e.g. covered by a push-through type lidding foil and the base part and lidding foil are releasably joined by sealing. The packaging containers may contain diagnostic aids for medical analytical equipment. In order to improve machine control, the packaging container may exhibit, e.g. at its outermost edge, markings that can be sensed either mechanically or optically.

[0057] The composite material may be fabricated in an endless form (rolls, coils) and be shaped in this form before being divided into individual lengths, or the composite material may be produced in individual lengths or in an endless form and the individual lengths shaped and processed further.

[0058] The present invention also relates to the use of the packaging container according to the invention for packaging pharmaceuticals, medical aids, diagnostic aids and other products that are sensitive to temperature, light, gas and/or moisture. This means that the packaging containers are suitable e.g. especially for packaging substances that should be protected to prevent substances in the contents, such as e.g. gases, solvents or aromatic substances from diffusing out of the packaging. Further, the packaging container also protects contents from external influences such as those of a mechanical nature as well as diffusion of gases, vapours and fluids and protects them from electromagnetic radiation such as light.

[0059] The shaped packaging material according to the present invention exhibits a high degree of flatness i.e. also after shaping the packaging containers and the contents do not arch, this neither as endless material, in single lengths nor as shaped packaging container. As a rule the shaped packaging container exhibits a high degree of stiffness, the high degree of flatness always being provided independent of the stiffness. The packaging containers are intact and do not exhibit any cracks as a result of processing.

[0060] The high degree of stiffness and flatness can be improved further by a symmetrical make up of the composite material. It was to be expected that a stiffening of the composite material could be achieved by strengthening the inner layer. It was found, however, that as a result of an additional outer layer and symmetrical make up, a surprising improvement in the properties of the composite and the packaging container made therefrom can be achieved.

[0061] Further, a reduction in migration, both from inside to outside and in the opposite direction, was observed—this also through a thinner sealing joint between the packaging container and the lid.

[0062] The packaging material exhibits a high degree of formability and packaging containers of widely different shapes may be made from it.

[0063] As a result of the symmetrical make up of the packaging material, the latter exhibits a low degree of spring-back when formed.

[0064] As a result of the make up according to the invention, the packaging container obtains stiffening due to the outer part of the composite; at the same time, however, a high degree of formability is achieved with minimum spring back.