Transparent Base and Gum Composition

The present invention relates to a gum base and gum composition that is substantially transparent.

Conventional chewing and bubble gum bases generally contain elastomers, elastomer plasticizers, fillers, waxes, and softeners. The elastomers include natural rubber such as smoked or liquid latex and guayule, natural gums such as jelutong, lechi caspi perillo, massaranduba balata, massaranduba chocolate, nespero, rosidinha, chicle, gutta percha, gutta kataiu, niger gutta, tunu, chilte, chiquibul, gutta hang kang and synthetic rubber such as butadiene-styrene copolymers, polyisobutylene, isobutylene-isoprene copolymers, polybutadiene, vinyl polymers such as polyvinyl acetate, vinyl copolymers such as vinyl acetate/vinyl laurate, ethylene/vinyl acetate and the like.

Typical elastomer plasticizers are natural rosin esters such as glycerol ester of partially hydrogenated rosin, glycerol ester of polymerized rosin, glycerol ester of partially dimerized rosin, glycerol ester of rosin, glycerol ester of tall oil rosin, pentaerythritol esters of partially hydrogenated rosin, partially hydrogenated methyl esters of rosin, pentaerythritol ester and synthetic resins such as terpene resins derived from alpha-pinene, beta-pinene and d-limonene.

Typical waxes are synthetic waxes such as polyethlene and Fischer-Tropsch waxes, natural waxes such as candelilla, carnauba, beeswax, rice bran or petroleum waxes such as microcrystalline and paraffin.

Typical fillers include carbonate types such as magnesium and calcium carbonate, ground limestone and silicate types such as magnesium and aluminum silicate, clay, alumina, talc, as well as titanium oxide, mono-, di- and tri-calcium phosphate, cellulose polymers such as ethyl, methyl and wood and the like.

Typical softeners include hydrogenated vegetable oil, nonhydrogenated vegetable oil, lard, hydrogenated tallow, coca butter, glycerol monostearate, lecithin, mono-, di- and triglycerides, acetylated mono-, di- and triglycerides, distilled mono-, di- or triglycerides, glycerol triacetate, fatty acids such as stearic palmitic, oleic linoleic and linolenic and the like.

Other ingredients such as antioxidants and colorants may also be present.

Conventional chewing gums using these gum bases generally contain water-soluble, natural or artificial bulk sweeteners, water-soluble binding syrups, natural and artificial, liquid or dried flavorants, softeners and emulsifiers.

Conventional gums generally use water-soluble natural or artificial bulk sweeteners such as sucrose, dextrose and sorbitol, along with binding syrups such as corn syrup, starch hydrolysates and 70% sorbitol solution. Conventional gums also include natural and artificial, and liquid or dried flavorants, softeners such as glycerine, propylene glycol, ad emulsifiers such as glycerol monostearate or lecithin.

Skilled artisans have combined these ingredients in various ways to create chewing gums and bubble gums that have various flavors, good texture and mouth feel, and (in the case of bubble gums) good elasticity and bubble characteristics.

Due to the combinations, types and levels of ingredients used in conventional gum base and gum products, however, they tend to be visually opaque when formed into the final shape and will either block or greatly diffuse the transmittance of visible light.

This invention is a transparent gum base and transparent finished gum composition. The transparent gum composition of this invention comprises:

from abut 70.0 percent to about 95.0 percent by weight of one or more elastomers selected from the group consisting of a polyvinyl acetate having an average GPC molecular weight from about 2,000 to about 85,000,

a polyisobutylene having an average GPC molecular weight from about 50,000 to about 95,000, and

a vinyl laurate-vinyl acetate copolymer having an average vinyl laurate content from about 10.0 percent to about 60.0 percent by weight of t he copolymer;

from about 1.0 percent to about 20.0 percent by weight of one or more softeners selected from the group consisting of glycerol triacetate, mon-, di- or triglycerides or acetylates mono-, di- or triglycerides and preferably those having a saponification number greater than about 350 and even more preferably greater than 400.

less than 1 percent by weight filler,

wherein the gum base has a light transmittance of at least 60 percent using ASTM Method D1746-35, and a softening point of from about 40.degree. C. to about 90.degree. C.

The transparent gum composition of this invention comprises at least 75.0 percent by weight of the transparent gum base of t his invention; no more than about 10.0 percent of oil-or water-soluble flavoring; and no more that about one percent of a high-intensity sweetener wherein the transmittal of light is at least 60 percent.

Optional opaque ingredients may be included in either the gum base or finished gum composition at low levels so as to maintain the light transmittance above 60 percent. Preferably, the amount of opaque ingredients is below 5.0 percent.

Other features of this invention will be apparent from the detailed description below.

As described above, the transparent gum base elastomer can be polyvinyl acetate (PVA) having an average GPC molecular weight from abut 2,000 to 85,000. Maintaining an average GPC molecular weight can be accomplished in several ways. First, the PVA can be selected so it clearly falls within the range. Also, a blend of PVAs of different molecular weights can be formulated so that the average molecular weight falls within this range.

For example, a blend of a low molecular weight PVA (e.g. from 2,000 to 15,000, preferably from 10,000 to 14,000) and a high molecular weight PVA (e.g. from 45,000 to 95,000, preferably from 46,000 to 55,000) can be made. Preferably, the ratio of high to low molecular weight PVA is from 2 1 to 1:9.

Alternatively, a blend of a medium molecular weight PVA (e.g. from 15,000 to 45,000, preferably from 25,000 to 35,000) and the low molecular weight PVA previously described can be made. Preferably, the ratio of medium to low molecular weight PVA is from 7:1 to 1:7.

Also, a blend of a high molecular weight PVA (e.g. from 45,000 to 95,000, preferably 46,000 to 55,000) and the medium molecular weight PVA previously described can be made. Preferably, the ratio of high to medium molecular weight PVA in such a blend is from 1:1 to 1:8.

However, the molecular weight of the PVA is controlled to be within the range of 2,000 to 85,000, it is preferred that the molecular weight of the PVA be between 7,000 and 60,000, and more preferably 10,000 and 30,000. While PVA can be used in the gum base in amounts from 70.0 to 95.0 percent, the preferred amounts range from 85.0 to 95.0 percent if PVA is the sole elastomer.

It is also possible to use a polyisobutylene as a gum base elastomer having a GPC molecular weight from 50,000 to 85,000, as mentioned previously. Preferably, polyisobutylene is used in combination with a PVA so that the polyisobutylene content is no more than about 40.0 percent by weight of the base, preferably from 5.0 to 35.0 percent, and more preferably from 17.0 to 31.0 percent. When polyisobutylene is used in combination with another elastomer such as PVA, the GPC average molecular weight of the elastomer mixture is from 45,000 to 90,000 and preferably from about 55,000 to about 80,000.

A vinyl laurate/vinyl acetate copolymer can also be used as an elastomer in the gum base of this invention. Preferably, that copolymer has a vinyl laurate content of from 10.0 to 60.0 percent, preferably from 15.0 to 45.0 percent.

Other substantially transparent polymers (e.g. ethylene vinyl acetate) can be used. However, their levels should be less than about 10% of the gum base because for ethylene vinyl acetate levels exceeding about 10% by weight create problems with texture in the finished gum products.

As set forth above, the amount of softener in the gum base of this invention is from 1.0 percent to 20.0 percent by weight. The preferred softeners are those that are themselves substantially transparent (e.g. glycerol triacetate, acetylated monoglycerides, preferably acetylated monoglycerides having saponification values above 400, and fats and oils having melting points above 65.degree. F. (the storage temperatures of the gum). Preferably, such transparent softeners are included in an amount ranging from 3.0 to 12.0 percent by weight of the gum base.

Opaque softeners can be employed at low levels (less than about 5.0 percent by weight) in the gum base. Typically low levels of opaque softeners may be used because of their strong elastomer softening capability. They include but are not limited to hydrogenated vegetable oil, lard, hydrogenated tallow, cocoa butter, glycerol monostearate, lecithin, mono-, di- and triglycerides, acetylated mono-, di- and triglycerides, distilled mono-, di- and triglycerides, glycerol triacetate, fatty acids such as stearic, palmitic, oleic, linoleic and linolenic and the like.

Preferably, with the preferred polyvinyl acetate elastomer, glycerol triacetate and mono-, di-, and triglycerides including those having a saponification number greater than 400 are employed. Even more preferred is glycerol triacetate used from about 3.0 percent to about 12.0 percent by weight of the gum base.

All or a portion of the total gum base may be added during the finished gum production. It is preferable, however, to add the majority of or all of the softener during the base production. Examples of adding softener in the gum composition are when the softener is present in the center-filling, (e.g. flavor oils as well as others including opaque types), and those added before or after the gum base is added in the gum production process, (e.g. those mentioned transparent softeners as well as less than about 5.0 percent of the opaque softeners, by weight of the gum composition).

The fillers in the present invention can be employed below about 1 percent by weight of the transparent base. Preferably the base is free of filler. The filler used in the present invention may include but is not limited to carbonate types such as magnesium and calcium carbonate, and ground limestone, and silicate types such as magnesium and aluminum silicate, clay, alumina, talc, as well as titanium oxide, mono-, di- and tricalcium phosphate, and cellulose polymers such as ethyl, and methyl cellulose and wood and the like.

Optionally, other typical gum base ingredients that are not in themselves transparent may be included in the present invention provided they are present at a level below from about 5.0 percent by weight of the gum base and preferably below about 3.0 percent. Such optional ingredients include but are not limited to synthetic rubber such as butadiene-styrene copolymers, isobutylene-isoprene, elastomer plasticizers such as natural rosin esters such as glycerol ester of partially hydrogenated rosin, glycerol ester of polymerized rosin, glycerol ester of partially dimerized rosin, glycerol ester of rosin, glycerol ester of tall oil rosin, pentaerythritol esters of partially hydrogenated rosin, partially hydrogenated methyl esters of rosin, pentaerythritol ester and synthetic resins such as terpene resins derived from alpha-pinene, beta-i-pinene and d-limonene, synthetic waxes such as polyethylene and Fischer-Tropsch waxes, natural waxes such as candelilla, carnauba, beeswax, rice bran or petroleum waxes such as microcrystalline and paraffin and the like. Use of these optional ingredients may be to improve the flavor profile of the gum.

Preferably hydrogenated and partially hydrogenated vegetable oils are used and even more preferably from about 1.0 percent to about 5.0 percent partially hydrogenated vegetable oil by weight of the gum base.

As set forth above, the transmittance of the gum base and finished gum of this invention (exclusive of an opaque-type center-filling) is greater than 60 percent, preferably greater than 80 percent, as measured by ASTM Dl746-35. Colorants can be added to the base and/or finished gum that may reduce the transmittance below 60 percent for the particular wavelength of light the colorant absorbs. Such colored bases and gum compositions are within the scope of the present invention if the total visible light transmittance is 60 percent or greater.

The base of the invention is typically prepared by adding an amount of the elastomer and softener to a heated sigma blade mixer with a front to rear speed ratio of typically 2:1. The initial amounts of ingredients is determined by the working capacity of the mixing kettle in order to attain a proper consistency. After the initial ingredients have massed homogeneously, the balance of the softener and/or optional ingredients aforementioned is/are added in a sequential manner until a completely homogeneous molten mass is attained. This can usually be achieved in one-half to three hours, depending on the formulation. The final mass temperature can be between 70.degree. C. and 130.degree. C. and preferably between 100.degree. and 120.degree. C. The completed molten mass is emptied from the mixing kettle into coated or lined pans, extruded or cast into any desirable shape and allowed to cool and solidify.

The use of a vacuum connected to the mixing chamber of the heated mixer is important. Since processing of the inventive gum base produces air bubbles which, upon cooling of the base, become entrapped and can result in an opaque product. While the vacuum method can be used, any means of vacuum processing applied to the gum base or to the gum made using said base or to either of their processes and which removes entrapped air may also be utilized.

Transparent bases of this invention such as those set forth in Tables I-II below may be prepared by adding the transparent ingredients to a pre-heated steel sigma blade mixer. The ingredients can be comminuted previously to reduce strain on the mixer. Various means of eliminating or prohibiting air bubble formation during mixing can be used, but vacuum is the preferred method. A mixer specially fitted with a vacuum cover can be used to achieve a low pressure (1-3 in. Hg) in the mixer to eliminate any air bubbles that may become entrapped in the final compound. Reducing the air trapped in the base improves the transmittance of light through the finished base.

The inventive gum consists of from about 75 percent to about 100 percent of inventive base and preferably from about 95 percent to about 100 percent by weight of the gum composition.

The final gum product (e.g. center filled gum having a transparent outer portion encasing a colored and visible center-filling) is also essentially transparent and can be likened in appearance to a typical hard candy.

Flavorants and sweeteners may also be eliminated from the finished gum mass itself and instead incorporated into a center-filling. In this approach, the base portion of the gum would consist of entirely suitable transparent base ingredients wherein the colors, flavors, sweeteners and the like are incorporated into a center-filling, and released only during chewing to commingle with the transparent base shell. Special equipment is necessary for center-filling, such as a Hamac-Holler Uniplast, and others well known in the industry. The center-filling may be either a dry powder consisting of water-soluble colors, sweeteners such as sucrose, xylitol, dextrose, fructose and spray-dried flavors. It may also be a liquid or semi-viscous fluid consisting largely of syrups such as high fructose corn syrup, regular corn syrup, hydrogenated corn syrup, sorbitol solution, water, glycerine, propylene glycol and thickeners such as methylcellulose and vegetable gums, sweeteners such as xylitol, sucrose, aspartame, thaumatin, monellin, alitame, acesulfame-potassium, saccharin, colors and liquid or dry flavorants.

The center-filling need not be transparent. The outer "shell" of transparent chewing gum or base can be transparent, permitting the consumer to see the center-filling that can be colored to impart an interesting and attractive appearance to the finished gum.

Depending upon the use of the product, powdered or liquid medicaments such as vitamins can be incorporated in the center-filling.

The shape of the final product will depend upon the dies used in the forming machine. Dies such as those used in the candy industry are preferred, since this gum is flexible and plastic when warm, but yields a very sharp glass transition (Tg) upon cooling and sticking to the dies is virtually eliminated. The glass transition temperature is a rheological value that is obtained when a polymer passes from a glassy state to a rubbery or liquid state. This occurs when the storage modulus (G") of a polymer is equivalent to l3 dynes/cm as measured on a rheometer.

The gum base and finished gum described above can be prepared in a number of different ways. Several examples are provided below that are intended to illustrate, but not limit, this invention. Table I and II provide formulations of gum bases of this invention. Table I further provides examples (G and H) of "controls" that are not substantially transparent. Table III provides examples of finished gum compositions of this invention.

The initial amounts and sequence of ingredient addition to the mixer depends on the size, working capacity and horsepower of the mixer. Preferably, the comminuted elastomer is allowed to soften or compound in the mixer at typically slow speed until workable into a mass to which the transparent softeners are added sequentially until a completely homogeneous mixture is attained. This can take from fifteen minutes to two hours, preferably thirty minutes to one hour, depending upon the amount of heat used and the base formulation used. A final temperature of between 50.degree. C. and 150.degree. C. and preferably between 90.degree. C. and 120.degree. C. is typical. The completed molten mass can be emptied from the mixer into coated or lined pans or put into an extruder and processed into small pellets to cool and solidify. The base mixture can also be cooled in the mixer using cooling jackets. Thus, the same mixer (with the vacuum equipment) can be used to prepare the finished gum following the procedures described below. T2 TABLE I-Transparent Bases? Controls? -A? B? C? D? E? F? G? H? -ELASTOMERS ? ? ? ? ? ? ? ? -Polyvinyl Acetate -Low Mw 72 ? 40 ? --? --? 85 ? --? --? 54 ? -Medium Mw --? 40 ? 60 ? 70 --? --? --? 15 ? -High Mw 20 ? --? 5 --? --? --? 25 -Polyisobutylene --? --? 25 ? 15 5 14 10 15 ? -Vinyl Laurate/Vinyl --? --? --? --? --? 60 --? --? -Acetate Copolymer -SOFTENERS -Glycerol Triacetate 5 3 --? 10 5 --? 5 5 -Glycerides --? 4.6 --? --? --? --? 2 --? -Acetylated Glycerides --? --? 5 --? --? 20 --? 2 -FILLER -CaCO3 1 --? --? --? --? --? --? 3 -Talc --? --? --? --? --? 1 25 --? -OPTIONAL OPAQUE INGREDIENT -Terpene Resins 1 --? --? --? --? --? --? 3 -Rosin Esters --? --? --? --? --? --? 18 --? -Hydrogenated Veg. Oils --? --? --? 5 5 --? --? 1.7 -Butyl Elastomer --? 5 --? --? --? --? --? -Wax --? --? 4 --? --? --? 15 -FLAVORANT -Oil-soluble --? --? --? --? --? 5 --? 1 -Water-soluble --? 7 --? --? --? --? --? --? -Spray-dried 1 --? --? --? --? --? --? --? -INTENSE SWEETENER -Aspartame --? --? 1 --? --? --? --? 0.3 -Thaumatin --? 0.4 --? --? --? --? --? --? -100%? -

The light transmittance of bases "G" &"H" are less than 10 percent and less than 60 percent respectively.

The chewing gum of the invention is prepared by adding the bases of this invention to typically preheated mixing kettle such as sigma blade mixer at a temperature of approximately 45.degree. C. The base is melted at the lowest temperature possible to achieve efficient mixing while reducing air bubbles, i.e. by using the low level vacuum. When the base is sufficiently softened, the vacuum is removed and flavor is added, and the vacuum is again resumed until the gum is homogeneous. If a high intensity sweetener such as aspartame is used, it is added last to prevent degradation caused by excess heat. The finished gum mass is then removed from the mixer and rolled, pressed or center-filled as desired.

The amount of center-filling depends upon the sizing equipment, extruder and die head. It can be adjusted as desired. A typical level of filling would be 15% of the weight of the gum composition. For example, a three gram piece of gum could contain 0.45 gram of center-filling that is injected into the gum mass so that the gum forms a shell around the center-filling, or injected into a finished gum of this invention so that a finished gum forms the shell.