US2984244A - Tobacco composition - Google Patents

Description

United States Patent TOBACCO COMPOSITION Eric Bell Hotelling and Thomas Edward Kelly, Westport, Conn., assignors to International Cigar Machinery Company, Inc., a corporation of New Jersey No Drawing. Original application Sept. 30, 1959, Ser. No. 843,376. Divided and this application Apr. 7,

1960, Ser. No. 25,818

14 Claims. (Cl. 131-15) This invention relates to tobacco compositions containing finely divided tobacco, a water-insoluble adhesive derived from a polysaccharide and a polyester plasticizer. The invention further relates to articles such as sheets and filaments manufactured from such compositions and to methods of making both the compositions and the articles.

In forming and wrapping cigars and related smoking articles it is important that the tobacco material on the outside should stretch and cling resiliently to the filler or bunch on the interior as a close fitting skin. Some natural leaf tobacco has this property. It is of substantial technical value to be able to use manufactured tobacco sheets for the same purpose. Sheet and filament products of finely divided tobacco not only have economic and mechanical advantages in their case of automatic manipulation and saving on scrap, but also provide a means of blending different tobaccos.

An important consideration in formulation of tobacco sheet compositions is a close approach to the quality of natural leaf tobacco in flavor and smoke as well as burn rate and ash formation. These factors are influenced by the selection of suitable adhesives and plasticizers which are generally used in minimal amounts commensurate with strength and stretch. The tobacco content is therefore made as high as possible.

There is an inherent advantage in tobacco sheet and related products which have high resistance to attack by moisture, such as saliva and casing fluids. Accordingly, various systems have been developed for forming such articles from combinations of finely divided tobacco and water-insoluble ingredients, such as adhesives, which are manipulated in organic solvents.

An outstanding problem, not resolved or suggested in the prior art, is the production of tobacco sheet having not only good color, strength (both wet and dry), and

burn properties but also a high stretch or plasticity in combination with a high tobacco content (greater than two thirds by weight).

Therefore, it is an object of this invention to provide a tobacco composition from finely divided tobacco and a highly stretchable water-insoluble adhesive in combination with a plasticizer.

It is a further object to provide a tobacco sheet or filament having a high tobacco content, water insolubility and high stretch.

Another object of the invention is to provide smoking articles including cigars which are made at least in part from finely divided tobacco combined with a waterinsoluble adhesive which contains a high stretch ingredient.

Still another object of this invention is to provide methods of manufacturing tobacco compositions and articles from finely divided tobacco in organic solvent systems.

These and other objects of the invention are more fully set forth in the following detailed description and examples.

This invention is preferably realized by contacting finely divided tobacco with a water-insoluble adhesive dissolved in an organic liquid solvent in combination with the polyester plasticizer materials of the invention. It has been found that a rather specific group of polyesters adds valuable stretch properties to tobacco products when used in small amounts. Moreover, these materials do not seem to impair either the smoke or burning properties of the tobacco and further serve as auxiliary adhesives.

The ester polymers of this invention are prepared by combining dicarboxylic acids with aliphatic triols (straight groups). In selecting the desirable acids and alcohols to be used in this invention it is important to avoid heavy cross linking, through condensation, and the resulting rigid, infusible and insoluble alkyd materials. The desired polyester materials are probably slightly cross linked and are gummy. The polyesters of this invention may also be mixed and used with other plasticizers such as esters of dihydroxy alcohols including the glycols and with conventional humectants. These products are useful both as plasticizing and as adhesive materials.

The aliphatic long-chain dicarboxylic acids useful in this invention include glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, their higher homologues, and acids of this type which are substituted with lower alkyl groups.

A preferred embodiment of this invention utilizes polyesters prepared from mixtures of azelaic acid or sebacic acid with a dicarboxylic acid of shorter chain length to produce a mixed dicarboxylic acid with an average chain length of 7-9 carbon atoms. Dicarboxylic acids with chain lengths of less than five carbon atoms tend to produce rigid structures which are not useful in this invention. Certain of the dicarboxylic acids, succinic, adipic and suberic acids, produce solvent-insoluble polyesters when condensed in purified form with glycerol or other triols. It is preferable, therefore, to employ these acids as crude technical mixtures with other dicarboxylic acids or, if the purified acids are available, to add azelaic or sebacic acids to the reaction mixture to produce a lower-melting, less highly cross-linked polyester which will dissolve Substitution of these acids with lower alkyl groups (methyl or ethyl) also greatly reduces their tendency to resinify. A particularly suitable dicarboxylic acid technical raw material is Isosebacic Acid, a commercial mixture of about 10% sebacic acid, about 60% Z-ethylsuberic acid and about 30% 2,5-diethyladipic acid by weight.

Any aliphatic triol containing vicinal hydroxyl groups, which inhibit the cross-linking reaction, is useful in forming the polyesters of this invention. Preferred species of triol include glycerol and 1,2,6-hexanetriol. Glycerol is particularly preferred because it is cheap, readily' available and non-toxic.

The mole ratio of dicarboxylic acid to triol is critical and is at least 2:1 and not more than 3:1. Less than two moles of acid per mole of glycerol cause resinification, in most cases, to an insoluble alkyd-type polymer. Use of more than three moles of acid to one mole of glycerol leaves a residue of unreacted acid which tends to produce a fatty odor in the tobacco product.

Polyesters useful in this invention are produced by condensation of the dicarboxylic acids and glycols above within these proportions. The condensation can be carried out by any of the usual commercial or laboratory methods of esterification. One of the simplest procedures is to dissolve or suspend the reactants in benzene or toluene, add a few per cent of concentrated sulfuric acid or phosphoric acid as catalyst, distill oil? the water formed in the reaction as an azeotrope with the benzene or chain alcohols containing three hydroxy toluene, and collect the water in a trap for azeo-tropic removal of water with provision for the benzene or toluene to reflux into the reaction vessel. When evol tion of water ceases, generally after three to twelve hours at reflux temperature, the condensation is essentially' complete. The polyester may conveniently be employed in the crude benzene or toluene solution after separation of the acid catalyst, or it may be further purified if desired.

The benzene or toluene solution is fully stable for periods of several months if water is excluded and the acid efiiciently separated from the organic layer, In an alternate method, the benzene may be distilled oif in vacuo and the gummy polyester taken up in another suitable solvent such as methanol, ethanol or acetone. If rigid exclusion of acids is desired, the condensation may be carried out in a higher-boiling solvent, or under pres sure, without any catalyst other than an excess of dicarboxylic acid reactant.

Polyesters of this invention function as both plasticizers and auxiliary adhesives with tobacco. Formula tions containing them can tolerate a much higher tobacco loading than equivalent formulations plasticized with other materials.

The choice of the water-insoluble adhesive to be employed in preparing the tobacco products of this invention is subject to certain limitations. The material should be nearly tasteless and completely non-toxic in the concentrations used, should possess good burn odor, should be virtually insoluble in water but soluble in whatever organic solvent is chosen for the process to form a viscous solution which can be cast, sprayed or extruded, and from economic considerations should be inexpensive and readily available.

These limitations indicate the choice of the ester or ether derivatives of polysaccaride or carbohydrate high polymers such as cellulose, amylose and starches. Such materials, which are in widespread use, include cellulose esters, particularly cellulose acetate, the mixed esters such as cellulose acetate propionate and cellulose acetate butyrate, and cellulose ethers such as methylcellulose and ethylcellulose. The molecular weight and degree of substitution of the cellulose or other carbohydrate derivative must be in the proper range to produce the solubility and viscosity characteristics mentioned above. Within these limitations the particular adhesive chosen will depend upon the specific fiavor, burn odor and texture which the formulator wishes to impart to the finished smoking article. The preferred adhesives in formulations containing the polyesters of this invention are ethers of cellulose or amylose.

The solvent chosen for the manufacture of tobacco products of this invention must be one that dissolves the adhesive, evaporates easily and is preferably cheap and easily recoverable. High-speed drying at slightly elevated temperatures is desirable Among the common solvents it is preferable to employ methanol, but acetone, ethanol, isopropyl alcohol, benzene, toluene, chloroform and methyl butynol or mixtures of any of these can be used with particular adhesives and polyesters which dissolve in the solvent chosen.

Example I This example illustrates a preferred form of the invention.

A plasticizer soluition was prepared from 3058 grams (15.1 moles) of Isosebacic Acid (a commercial mixture of sebacic acid, 2-ethylsuberic acid, and 2,5-diethyladipic acid), 507 grams (5.5 moles) of glycerol, 107g. (3% by weight of reactants) of concentrated sulfuric acid (specific gravity about 1.84), and 7.0 liters of benzene. These ingredients were stirred and refluxed in a 22-liter, four-neck, round-bottom flask equipped with a motor stirrer, thermometer well, heating mantle, two reflux condensers and two modified Dean-Stark traps for collection of Water. After refluxing with stirring for a total of ten hours, the theoretical amount of water was collected from the traps and no further reaction was visible. The benzene solution of crude polyester was then separated from the lower acid layer. The polyester content, determined by drying a sample to constant weight, was 40%.

Ten grams of ethylcellulose (a commercial product described as having a medium ethoxy content and a viscosity of cps. measured in solution under standard conditions) were dissolved in 200 ml. of methanol. Then 5.0 grams of the benzene solution of polyester, containing 2.0 grams of active material, were added to the solution and completely dispersed in it. This was followed by 60.0 grams of dry ball-milled Havana Seed Tobacco, all of which had passed through a -mesh screen. The thick slurry was adjusted to 27% solids content by addition of more methanol and, after complete homogenization, was cast into sheets with a casting knife clearance of about six mils. The solvent was permitted to evaporate at room temperature and atmospheric pressure, and random samples of the sheets were removed for testing. The sheet tensile strength was over 450 grams per inch for a sheet weight of 5.90 grams per square foot. After soaking in water for 30 seconds the tensile strength of this sheet was still over 250 grams per inch, and the elongation at the breaking point was over 15%.

Cigarillos prepared on a cigarillo machine with this tobacco sheet as wrapper were quite satisfactory in taste and appearance. The wrapper contained over 83% tobacco and less than 2.8% polyester by weight on a dry basis.

Example 11 Tensile Strength, g./in.

Sheet Ethylcellulose, Polyester,

g. g. Tobacco Elong.

Dry Wet Wet (percent) Two conclusions may be drawn from this data. Sheets A, B, and C contain the same amounts of tobacco and ethylcellulose with variable amounts of polyester. Both the wet strength and the wet elongation of the sheets increases with increasing polyester concentration, indicating that the polyester functions both as a plasticizer and as an auxiliary adhesive. Secondly, sheets C, D, E, and F are composed of identical amounts of adhesive and polyester with variable quantities of tobacco. It is ap parent that the tensile strength and elongation both decrease with increasing tobacco content, becoming marginal for cigarillos at about 85% tobacco.

Example III A polyester solution was prepared by the procedure of Example I from technical azelaic acid (2.75 moles) and glycerol (1.0 mole) in toluene as the solvent and azeotroping medium. A portion of the product (2.0 grams, dry basis) was dissolved in methanol and mixed with 10.0 grams of ethylcellulose and 60 grams of tobacco to form a slurry with a solids content of 27%.

Sheets cast from this slurry with an eight-mil knife had the following properties:

Tensile strength, dry g./in 336 Tensile strength, wet g./in 205 Elongation, wet percent 18 Sheet weight g./ft. 6.90 Tobacco content percent 83 These sheets were successfully wrapped on cigarillos to produce smoking articles of excellent taste, appearance, and burn odor.

Example IV An attempt was made to prepare a polyester from suberic acid and glycerol by the procedure of Example III. The product was an alkyd resin which was insoluble in all common organic solvents. Likewise, the products of condensation of adipic acid or succinic acid with glycerol were insoluble polymers.

To illustrate means of overcoming this difliculty, a polyester was prepared from suberic acid (0.75 moles), azelaic acid (2.0 moles), and glycerol (1.0 moles) by the procedure of Example I. The product was soluble in a mixture of methanol and benzene, or in methanol or ethanol alone. Sheets were prepared from a 27% methanol slurry with a composition similar to those of Example III parts ethylcellulosezZ parts polyesters:60 parts tobacco), and after drying in air had the following properties:

Tensile strength, dry g./in.... 360 Tensile strength, wet ..g./in.. 257 Elongation, wet percent 17 Sheet weight g./ft. 6.20 Tobacco content percent 83 It will be noted that the addition of suberic acid, a shorter-chain dicarbyoxylic acid, to the reaction mixture resulted in a polyester which substantially improved the sheet tensile properties over those obtainable with azelaic acid alone. This sheet was also successfully wrapped on cigarillos to produce smoking articles of good quality and appearance.

Example V To illustrate the efiect of increasing the polyester content of tobacco sheets, the polyester of Example IV was incorporated into a 30% methanol slurry containing 10 parts of ethylcellulose, 3.3 parts of polyester, and 44.4 parts of tobacco. Sheets cast from this mixture had the following properties:

Tensile strength, dry g./in 806 Tensile strength, wet g./in..- 550 Elongation, wet percent 22 Sheet Weight g./ft. 8.85 Tobacco content percent 77 These sheets had enough stretch to be wrapped successfully on large (Perfecto) cigars to produce smoking articles of excellent quality and appearance. It is apparent from the sheet properties that tensile strength and elongation are improved by increasing the amount of polyester and reducing tobacco content.

Example VI To illustrate the efiect of increasing the amount of suberic acid in the polyester of Example IV, a similar product was prepared by the same procedure from suberic acid (1.25 moles), azelaic acid (1.5 moles), and glycerol (1.0 mole) in benzene solution. This material was also soluble in polar solvents, in contrast to the alkyd resin obtained from suberic acid alone.

Sheets were prepared with the same compositions as those of Examples IV and V, but incorporating the new polyester of this example in place of that of Example IV. The 10 parts adhesives:2 parts polyesterz60 parts tobacco formulation produced a sheet with the following properties using a methanol solvent:

Tensile strength, dry g./in

Tensile strength, wet g./in 255 Elongation, wet percent.. 18 Sheet weight g./ft. 6.36 Tobacco content percent 83 Tensile strength, dry g./in.. 714 Tensile strength, 'wet g./in 475 Elongation, wet percent 18 Sheet weight g./ft. 6.68 Tobacco content percent 77 Again there is no improvement in tensile strength or elongation over the sheets containing lesser amounts of suberic acid. This material made a satisfactory filler for cigarettes and also smoked well in a pipe.

Example V11 To illustrate the successful use of adipic acid in this invention a polyester was prepared from adipic acid (1.25 moles), azelaic acid (1.5 moles), and glycerol (1.0 mole) in benzene solution by the procedure of Example I. ,A sheet with the composition of Example IV was prepared with this polyester in methanol and had the following properties:

Tensile strength, dry g./in 375 Tensile strength, wet ..g./in 230 Elongation, wet percent-.. 13 Sheet weight g./ft. 6.45 Tobacco content "percent 77 It will be noted that addition of adipic acid to the reaction mixture produces a plasticizer with less favorable properties than that made with suberic acid. Nevertheless, this sheet could be wrapped on a cigarillo to give acceptable quality and appearance of the smoking article.

Example VIII To illustrate the use of aliphatic triols other than glycerol, a polyester was prepared by the procedure of Example I from azelaic acid (2.75 moles) and 1,2,6- hexanetriol 1.0 mole) in benzene solution. A sheet with the formulation of Example V was cast with a 30% methanol slurry and had the following properties:

Tensile strength, dry g./in 430 Tensile strength, wet g./in 340 Elongation, wet "percent..- '12 Sheet weight g./ft. 5.95 Tobacco content percent 77 This sheet was wrapped on a cigarillo to produce a smoking article of acceptable quality and appearance.

Example IX A series of polyesters was prepared from glycerol (1.0 mole) and varying amounts of azelaic acid by the procedures of Example III. It was found that when less than two moles of azelaic acid were combined with the glycerol an insoluble alykd resin was obtained. When two or more moles of azelaic acid were employed in the condensation the polyester was soluble in organic solvents, such as benezene, toluene, and methanol. These soluble polyesters were used to prepare tobacco sheets with the;

7 formulation or Example V (77% tobacco). The following data were obtained from the sheets.

Azelalc Tensile Tensile Elong., Sheet Acid, Strength, Strength, Wet, Weight Moles Dry g./in. Wet g./in. Percent g./ft.

All of these sheets could be wrapped successfully on large (Perfecto) cigars. The optimum combination of good physical properties and pleasant burn odor is at about a 2.75/1 .00 mole ratio of azelaic acid to glycerol.

Example X As an illustration of the wide range in physical properties obtainable with the polyesters of this invention, the plasticizer of Example III was employed in a number of different formulations with methanol with tobacco contents ranging between 70 and 83%. In one case, A, a humectant (triethylene glycol) was added to obtain increased flexibility and stable high water content. The formulations and sheet data are presented in the following table:

Sheet A B O D E Ethylcellulose, parts Polyester, parts. Tobacco, parts. Hurnectant, parts Tobacco content, percent Tensile strength, dry, g./in 312 480 475 625 336 Tensile strength, wet, g./in 258 275 282 276 205 Elongation, dry, percent 27 10 9 10 6 Elongation, wet, percent- 40 3O 20 24 18 Sheet weight, g./ft. 4. 35 4.85 4. 45 5. 59 6. 90

Example XI A polyester was prepared from glutaric acid (2.75 moles) and glycerol (1.0 mole) by the procedure of Example I. This was incorporated into a tobacco sheet with the formulation of Example V using methanol, and the following sheet data were obtained:

Tensile strength, dry g./in 639 Tensile strength, wet g./in 482 Elongation, wet percent 18 Sheet weight a ..g./ft. 6.20 Tobacco content percent 77 This sheet could be wrapped successfully on cigarillos to yield smoking articles of acceptable quality and appearance.

Example XII A polyester was prepared from sebacic acid (2.75 moles) and glycerol (1.0 mole) by the procedure of Example I. This was incorporated into a tobacco sheet with the formulation of Example V, and the following sheet data were obtained:

Tensile strength, dry -g./in 447 Tensile strength, wet g./in 299 Elongation, wet percent 25 She th eight, --g-/f Tobacco content percent- 77 8 A second sheet was prepared from the same polyester (2.5 parts) with 10 parts of ethylamylose and 50 parts of tobacco in benzene. These sheets had the following properties:

Tensile strength, dry g./in 350 Tensile strength, wet g./in 215 Elongation, wet "percent" 18 Sheet weight g./ft. 5.95 Tobacco content percent Both types of sheet could be wrapped successfully on cigarillos to produce articles of acceptable quality and appearance.

The auxiliary plasticizer-adhesivcs of this invention can be incorporated into a tobacco product such as a sheet in the manner described above to produce the beneficial plasticizing efI'ect necessary to make cigar wrappers which can be fed automatically from a bobbin to a cigar machine. Generally, flavoring and coloring materials, humectant, and other inert ingredients such as ash improvers are incorporated into cigar wrapper sheet. Cigars and cigarillos prepared from tobacco sheet wrapper of this invention are light in color, smooth in texture, uniform in quality, inexpensive, and do not dissolve or disintegrate in the mouth when wet with saliva. The same type of tobacco sheet, containing the plasticizers of this invention, may also be used as cigar binder or as a filler in the form of strands or filaments, which may be chopped, in other smoking articles such as cigarillos, little cigars, pipes or cigarettes. Some modification in sheet weight and in the proportions of the various in gredients employed may be used for the various applications mentioned.

The tobacco products of this invention generally con tain more than two thirds by weight of tobacco and may contain four fifths or more tobacco. Not only finely divided tobacco, but fibers from tobacco and other materials may be used. The polyester materials generally make up less than one eighth of the product and are preferably used in the range of 28% by weight. Other ingredients include some moisture, the adhesive and ash control materials.

Tobacco products may be made from the novel compositions of this invention by extrusion, casting, spraying or dip coating with a slurry of the ingredients in a solvent; or tobacco dust may be coated onto the wet solvent preparation of adhesive and polyester.

What is claimed is:

1. A composition of matter comprising in combination finely divided tobacco, a water-insoluble adhesive and a polyester of at least two moles of and not more than three moles of a dicarboXylic acid for each mole of an aliphatic triol.

2. A composition according to claim 1 in which the tobacco is dry ground.

3. A composition according to claim 1 in which the adhesive is a polysaccharide derivative. 4

4. A composition according to claim 3 in which the polysaccharide is derived from one of the group consisting of amylose, cellulose, and starches.

5. A composition according to claim 4 in which the polysaccharide is selected from at least one of the group consisting of esters and others.

6. A composition according to claim 4 in which the polysaccharide is selected from at least one of the group consisting of cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, methyl cellulose, ethyl cellulose and ethyl amylose.

7. A composition according to claim 1 in which the dicarboxylic acid is selected from at least one of the group consisting of glutaric, adipic, sebacic, pimelic, suberic, azelaic, their higher homologues and acids of this type substituted with lower alkyl groups.

8. A composition according to claim 7 which is derived from a mixture of at least two carboxylic acids.

9. A composition according to claim 1 in which the aliphatic triol is selected from at least one of the group consisting of glycerol and 1,2, fi-hexanetriol.

10. A composition according to claim 1 in which the polyester is partially cross linked.

11. As an article of manufacture, a tobacco sheet made from the composition of claim 1.

12. As an article of manufacture a smoking product 10 2,734,513 wrapped with the sheet of claim 11.

13. As an article of manufacture a filament of tobacco material made from the composition of claim 1.

14. As an article of manufacture a smoking product containing strands of the composition of claim 1.

References Cited in the file of this patent UNITED STATES PATENTS Hungerford et a1. Feb. 14, 1956 Hungerford et al. Feb. 14, 1956

Claims (1)

1. A COMPOSITION OF MATTER COMPRISING IN COMBINATION FINELY DIVIDED TOBACCO, A WATER-INSOLUBLE ADHESIVE AND A POLYESTER OF AT LEAST TWO MOLES OF AND NOT MORE THAN THREE MOLES OF A DICARBOXYLIC ACID FOR EACH MOLE OF AN ALIPHATIC TRIOL.