US2092817A - Impregnated cigarette - Google Patents

Description

Patented Sept. 14, 1937 UNITED STATES PATENT OFFICE IMPREGNATED CIGARETTE No Drawing. Application May 18, 1935, Serial No. 22,167

7 Claims.

This invention relates to the manufacture of cigarettes and more particularly to a method of treating the paper of the cigarette. to render the same waterproof and at the same time not to impair the smoking qualities of the finished cigarette.

It is well known that paper which is commonly used in the manufacture of cigarettes has the disadvantage that it readily disintegrates when it becomes wet or damp for any reason. The paper also has a definite tendency to stick to the lips, sometimes quite tenaciously. It is a common experience of smokers to have a cigarette become soggy due to the absorption of moisture by the paper and tobacco and to have the individual pieces of tobacco become loosened and remain in the mouth. Heretofore, these disadvantages have been partly overcome by coating one tip of the cigarette with straw, cork, bark, ivory, and materials of a similar nature. The main disadvantages of this practice are that the cost of cigarettes so prepared is high because of the special tipping operation required; the cigarette can be lighted at only one end; and only the tip is protected and rain or wet fingers readily cause the remaining part of the cigarette to disintegrate rapidly. Other expedients such as coating the cigarette or cigarette paper with cellulose derivatives, oils, waxes, etc. have been proposed, but in each case the appearance, burning rate, odor, or taste has been adversely influenced by the agent used.

The use of various resins for coating cigarette paper has also been proposed. It has been my experience, however, that the resins suggested in the prior art exert a more or less definite and undesirable transparentizing action on the paper, thereby altering its appearance. Apparently it is possible to obviate this transparentizing eifect by applying the resin in such a way as to produce an efllorescent coating on the paper, but this method is commercially undesirable because it involves the costly process of drying the paper, after it has been treated with a solution of the resin in organic solvent, in special and abnormal- 1y warm, humid atmospheres, in order to produce this blooming or blushing effect which masks the transparentizing action of the resin.

This invention has as an object the preparation of a cigarette which is resistant to moisture, at least over that part which is placed in the mouth and preferably over its entire length. A further object is the preparation of cigarette paper or the impregnation of the paper of a finished cigarette, without the necessity of resorting to spethe same time will not have adversely ailected its appearance, odor, taste, or combustibility.

These object'sare accomplished by treating the cigarette paper before or after the cigarette is made with dilute solutions or emulsions of certain synthetic resins not heretofore to my knowledge proposed for the purpose. The resins used in my invention are of the type which do not transparentize the paper; that is, they do not give the paper impregnated therewith the appearance of parchment but leave it in exactly the same condition, as far as may be observed, as the original paper. Furthermore, these eflects are secured without resorting to special solvents or special methods of drying.

It has been found that only limited and restricted classes of synthetic resins have the properties described above. Those with which the present invention is concerned are the polymeric esters of u-methylene carboxylic acids. This expression comprehends the mono or polyhydric alcohol or phenol esters of mono or polycarboxylic acids having a methylene group (=CH2) attached to a carbon atom adjacent to a carboxyl group. Within this field, the most generally useful agents are resinous polymers of compounds of the general formula where R is hydrogen or a monovalent hydrocarbon radical and R1 is a monovalent organic radical derived from a monohydric alcohol by removal of the hydroxyl therefrom. R1 may be the radical of a saturated or unsaturated, straight or branched chain, aliphatic, alicyclic or aromatic alcohol, which alcohol may or may not contain other groups such as ketone, ether, amino, etc. The following specific resins, derived from compounds of the above general formula, may be used in the practice of this invention: methyl alpha-methacrylate (the outstanding resin), cyclohexyl alpha-methacrylate, isobutyl alpha-methacrylate, ethyl alpha-methacrylate, methyl acrylate, isopropyl acrylate, diethylaminoethyl alpha-methacryl-ate, ethoxyethyl alpha-methacrylate, benzyl alpha-methacrylate ethyl alphaethacrylate, methyl alpha-phenacrylate, methyl alpha-cyclohexyl arcrylate, etc. Other esters of a-methylene carboxylic acids whose polymers may be used in this invention are diethyl itaconate and other esters of itaconicacid. I may also use in my invention interpolymers or mixtures of polymers of different esters of e-methylene carboxylic acids.

The following examples be carried out. However, the practice of the invention is not limited to the examples since modifications thereof will be readily apparent to those skilled in the art.

This solution was brushed on approximately inch of the tip of a cigarette with a small camel's hair brush. The solution penetrated the paper and within one minute at approximately 25 C. the treated paper tip was perfectly dry and no different in appearance from the remainder of the cigarette. The treated tip was waterproofed to the extent that it could be rubbed between moist lips without any effect on the paper and a definite line of demarcation existed between the treated and untreated portions of the cigarette when moistened by the tongue or lips.

The cigarette maybe rendered waterproof over its entire length by brushing the above resin solution over the remainder of the cigarette.

Example: II

Parts Methyl methacrylate polymer 0.5 Toluene 99.5

100.0 Example III Parts Methyl methacrylate polymer 1.5 Butyl acetat 20.0 Acetone 77.5 Dibutyl phthalate -1.0

100.0 Example IV Parts Cyclohexyl methacrylate polymer 2 Xylene 3 Petroleum ether 20 Ethyl acetate 75 Example V Parts 25% methyl acrylate'l5% methyl methacrylate interpolymer 2 Butyl acetate 10 Acetone 88 100 Example VI Parts Diethyl itaconate polymer 2.5 Butyl acetate 14.0 Acetone 83.5

Cigarettes treated with a solution prepared according to any one of the above examples are rendered definitely waterproof and at the same time no difference between these and untreated cigarettes may be detected in respect in which parts given are by weight, illustrate how the invention may to odor, taste, appearance, and rate of burning.

In connection with this latter test, 'two cigarettes, one which had been treated and the other which had not been treated, were lighted and smoked for about 4 inch and then laid side by side at the edge of a table. The cigarettes burned at the same rate and there was no evidence to indicate that the coatings had any effect whatever on the combustibility or burning qualities of the cigarettes. In Example III given above, it willbe noted that dibutyl phthalate has been added to the resin solution. A plasticizing agent of this type may be added where increased piiability of the treated paper is desired or where the resin is friable. It will be readily apparent that the amount of plasticizing agent may be increased or decreased to obtain the results desired; and, further, no limitation is placed on the particular plasticizer which may be used other than the fact that it must not be poisonous or have an offensive odor.

While I have given examples where the resin is dissolved, I may resort to aqueous emulsions particularly where the coating is applied to the paper before it is made into a cigarette. The expense and fire and health hazards of handling organic solvents are thus avoided. Unlike solutions, emulsions do not vary greatly in viscosity with different resins and difierent concentrations and as a result lend themselves more readily to application in one operation of the same amount of difierent resins or different amounts of the same resin.

In the practice of this invention it is preferable to use dilute solutions or emulsions, for example in the range from 0.5 to 2.5% resin by weight. This concentration may, however, be varied beyond these limits. For example, if a resin of very low viscosity is used or if the solvent selected is particularly active, the percentage of resin may be increased. On the other hand, the solution may be made as thin as desired but if carried too far in this direction, a plurality of impregnations or coatings will probably be necessary. Pigmented compositions may in some instances be used to advantage. It has also been found that in addition to solvent, resin, and plasticizer, small amounts of cellulose derivatives such as cellulose nitrate, cellulose acetate, ethyl cellulose and other esters and ethers may be incorporated into the impregnating compositions. These compounds should be added, however, in amounts small enough so that they will not seriously influence the rate of burning or taste of the cigarette.

While I have indicated that the resin solution may be brushed on the paper of the cigarette, it is obvious that other conventional methods may be used such as spraying or dipping. It is also within the scope of this invention to treat the cigarette paper with the resin before the cigarette is rolled by dipping the paper in the resin solution or emulsion, or by applying the resin to one side or both sides of the paper. The untreated cigarette may also be passed over rolls one side of which is immersed in the resin solution or emulsion.

I believe that the unaltered appearance of my I coated cigarettes is due to the fact that the resins indices such as 1.515, 1.54 and 1.64. The refractive index of cigarette papers ranges from 1.53 upwards. The resins which I use, however, have values of around 1.47 and. 1.18. The objects of this invention can therefore be accomplished by the employment of any synthetic resin which has a refractive index substantially lower than that of the cigarette paper.

It is apparent that many widely difierent em-- bodiments of this invention may be made without departing from the spirit and scope thereof;

and, therefore, it is not intended to be limitedinous polymer of a compound having the formula where R is a member of the group composed of hydrogen and a monovalent hydrocarbon radical and. R1 is a monovalent organic radical derived from a monohydric alcohol by removal of the hydroxyl therefrom.

3. A cigarette having the paper thereof treated with a composition comprising essentially a resinous polymer of methyl alpha-methacrylate.

4. In the manufacture of cigarettes the step which comprises treating the cigarette paper with a composition comprising essentially a resinous polymeric ester of an alpha-methylene carboxylic acid.

5. In the manufacture of cigarettes, the step which comprises treating the cigarette paper with a composition containing 0.5-2.5% of a resinous polymeric ester of an alpha-methylene carboxylic acid.

6. In the manufacture of cigarettes the step which comprises treating the cigarette paper with a composition containing 05-25% of a resinous polymer of a compound of the general formula where R is a member of the group composed of hydrogen and a monovalent hydrocarbon radical and R1 is a monovalent organic radical derived from a monohydric alcohol by removal of the hydroxyl therefrom. I

'7. In the manufacture of cigarettes the step which comprises treating the cigarette paper with a composition containing 0.5-2.5% of methyl alpha-methacrylate ,resin.

- DANIEL E. STRAIN.