US3106211A - Tobacco product - Google Patents

Description

United States Patent 3,106,211 TOBACCO PRODUCT William G. Reynolds, Richmond, Va, and Alex Cybriwsky, Louisville, Ky, assignors to Reynolds Metals Company, Richmond,'Va.,'a corporation of Delaware No Drawing. Filed Dec. 17, 1959, Ser. No. 860,089 1 Claim. (Cl. 131-47) This invention relates to novel cigarette md smoking tobacco including an additive, which tobacco when burned will produce smoke which is substantially lower in tar and nicotine content. More particularly, the invention concerns reconstituted tobacco containing an aluminiferous additive, and blends thereof with cigarette and smoking tobacco.

This application is a continuation-impart of application Serial No. 765,963, filed October 8, 1958, which is in turn a continuation-impart of application Serial No. 754,183, filed August 11, 1958, now abandoned, which is in turn a continuation-in-part of application Serial No. 696,900, filed November 18, 1957, now abandoned.

During the past few years extensive discussion has appeared in medical and public health circles and publications concerning the alleged carcinogenic and other harmful effects of smokers articles, particularly cigarettes. Statistical evidence has accumulated which tends to show a higher incidence of cancer of the throat and lungs in smokers than in the case of nonsmokers. These carcinogenic effects are generally ascribed to the presence in cigarette smoke, and to a lesser extent in cigarette paper smoke, of certain polycyclic aromatic hydrocarbon compounds containing fused ring structures, which are known carcinogens. Polycyclic aromatic organic compounds of this class are typically formed during the pyrolysis or destructive distillation of carbon-containing materials at elevated temperatures. Thus, for example, such compounds as 3.4-benzyprene and 1.2.5 .G-dlbGIlZEtl'llhlfiCCllfi are known to be strongly carcinogenic substances.

Recent studies have indicated that the leaves (cutin and rays) of the tobacco plant contain both natural waxes of paraffinic character, and phytosterols, which are solid alcohols of high molecular weight and carbon content,

and included a steroid structure. These substances remain in tobacco mixtures formed by processing of tobacco in accordance with prevailing industrial methods. When the tobacco is burned, as in the body of a cigarette or the bowl of a pipe, destructive distillation or pyrolysis of the carbon compounds, including these parafiins and phytosterols, is initiated, and is accompanied by formation of volatile combustion products. These products, moving from the point of burning into an adjacent distillation zone, include, in addition to carbon dioxide, water vapor, and ash particles, numerous volatile organic compounds, some of which are toxic or irritants. However, the real significance of the zone into which volatilization and distillation of the tobacco and paper combustion products is taking place lies in the fact that it provides, by virtue of its elevated temperature, which normally approaches that of the burning point itself, a region in which the initial products of pyrolysis or destructive distillation can undergo those chemical transformations and combinations which result in the formation of carcino genie and other objectionable compounds. Hence the lower the temperature of the region where such carcinogenic compound formation is prone to occur, the less is the likelihood of a dangerous proportion of carcinogens being formed. Experimental research has revealed that the carcinogenic compounds resulting from tobacco p-y- ICC rolysis are formed chiefly at temperatures above about 800 C. Below about 700 C. relatively small amounts are formed, and at about 600 C. and less, no aromatic polycyclic compounds are found in the pyrolysis products.

Thus, by providing means by which the character or" the combustion of the tobacco can be controlled, the

tar and nicotine content of the smoke can be achieved,

in comparison with untreated tobacco.

The aluminferous substance may be incorporated with either regular tobacco or into reconstituted tobacco. For purposes of this invention the term reconstituted tobacco refers to tobacco particles of sheet prepared either from regular tobacco or from waste fines, field scrap (farm damaged leaves), stems and dust, which are customarily cut or comminuted and formed itno sheets usually with the aid of a suitable binding agent, and afterward converted to filaments by shredding, or into strips, for the preparation of cigars, cigarettes, and the like.

Aluminferous materials or substances suitable for use as additives to tobacco in accordance with this invention include the hydrated oxides :of aluminum, and specifically the activated hydrated oxides. Examples of such bydrated oxides or aluininas, include activated alumina, crystalline hydrated alumina, and activated bauxites from which organic or inorganic materials have been removed which may be harmful to the human body if taken internally.

These aluminas are all nontoxic and relatively stable under ordinary conditions of temperature and humidity. They all contain definite amounts of sor-bed or combined water which are readily releasable when the aluminas are exposed to heat, and to the extent that such released moisture is available, the presence of these additives in the burning tobacco may tend to reduce the temperature of the combustion. However, the tar and nicotine reducing action of the additives in the quantity employed is unexpected and unique, and appears to be due to partially unexplained factors not related to the presence of contained or released moisture, although the latter may exert an independent favorable effect. It appears that more complete combustion occurs with the production of a greater amount of volatile materials.

The hydrated aluminas which are suitable for incorporation into regular or reconstituted tobacco in accordance with the invention include the crystalline hydrates represented by the formulas Al O .3l-l O or Al(OH) They are dry, free-flowing, white crystalline products, and are produced from dry process sodium aluminate which has been fired to about 1200 C. whereby virtually all organic contaminants are burned off. They have the following typical analyses (in percent or dry basis):

Percent (maximum) A1 0 64.5 bla o 0.35 as a;

1 2 F6 0 0004-0030 Free H O 0.1

The combined water is releasable on heating to about 110 C. or more.

Instead of hydrated alumina, there may be employed as a tobacco additive, in accordance with the invention, activated alumina, which is defined as essentially a mixture of various crystalline forms of aluminum oxide. Activated alumina is a material having a low density, a large surface area per unit of weight, and a highly porous structure. It is produced by heating alumina hydrate to a temperature sufficient to drive off most of the combined water, but it is capable of absorbing from about 16% to 20% additional moisture, depending upon the relative humidity and temperature of the atmosphere to which it is exposed. The absorbed moisture is readily and rapidly releasable at elevated temperatures such as occurs at the burning temperature of a cigarette.

As an alternative to activated alumina, there can be used as tobacco additive, activated bauxite. This is prepared from bauxite in a manner similar to that by which activated alumina is prepared from alumina hydrate. Bauxite is a naturally occurring ore of aluminum and is an impure form of alumina, primarily alumina trihydrate, containing small amounts of iron oxides and other iInpurities. The activated form can have a residual moisture as low as about 2% and can be hydrate up to about 26% moisture, which is releasable upon heating.

These various aluminas can, if desired be dyed with a tinting agent to match tobacco shades. The dye used to tint the tobacco may be a non-toxic food dye or other suitable dye. It is preferred to mix a dry aluminiferous additive with a dye and ferric ammonium oxalate to which is added one-half by weight of water. From the ferric ammonium oxalate ferric oxide is precipitated into the pores of the aluminiferous additive and then dried. This inclusion of an oxidation agent deposited on the activated aluminiferous additive is important to aid in the complete combustion of the tobacco. The oxidation agent may serve to reduce the initial ignition temperature. Because of the large surface area and porosity of the alumina it functions both as a carrier for and possesses chemical affinity for the ferric oxide. One method of thus tinting the aluminas is to apply to the finely divided material a solution of ferric ammonium oxalate, having a concentration between 0.5% and about 10%, as for example, 20 g. per liter, at a temperature of about 140 F. for a period of 2 to 5 minutes. The coloring material may be applied by spraying or by immersing the alumina therein.

The particle size of the aluminiferous material to be added to the tobacco sheet is an important factor. The particle size of the alumina should not exceed the thickness of the tobacco sheet but should not be less than about 1 micron. It has been found that a suitable particle size for the alumina additive will range between about or less retained on a 200 mesh sieve, to from about 60% to about 90% passing through a 325 mesh sieve. The particle size of the aluminiferous material will, in general, have a minimum particle diameter of about 10 microns, an average particle size of 30 microns and a maximum particle size of 60 microns. Thus, a particularly suitable form of the aluminiferous materials have the following analyses:

DISTRIBUTION ACCORDING TO PARTICLE DIAMETER (IN MICRONS) Percent +30 microns 29.9 -30 to 20.9 -20 to +10 27.4 10 to +5 15.0

The preparation of a tinted activated alumina suitable for use as an additive in tobacco in accordance with this invention is illustrated by the following example, but the example is not to be considered as limiting in any way:

4 Example 1 A hydrated alumina having the following dry screen analyses:

PERCENT FINER THAN INDICATED MESH and having a particle size range of 29.9% greater than 30 microns, 20.9% between 20 and 30 microns, 27.4% between 10 and 20 microns, 15% between 5 and 10 microns and 6.8% less than 5 microns, was placed on one inch thick trays in a brick furnace provided with bottom burners, a temperature control device, and a thermocouple. The alumina was activated by raising the furnace temperature to 750 F. in the course of about 6 hours and maintaining the temperature at this level for another 2 to 2 /2 hours, during which period activation of the alumina took place. After shutting off the heat, the alumina was left in the furnace for another 5 to 6 hours to cool. The product was then mixed with crystalline ferric ammonium oxalate in a ratio of 5 lbs. ferric ammonium oxalate to 100 lbs. of activated alumina to obtain a uniform mixture. To this mixture water was added in the amount of 1 pound per pound of mixture. After a 20 minute period during which the activated alumina was impregnated with ferric oxide, the mixture was filtered by suction and the residue placed back in the furnace and heated for 6 to 8 hours at 600 F., with an additional 4 hours cooling period.- During this heating the oxalic acid and the ammonia are volatilized, and removed. The dry activated alumina contains from about 0.55% to 0.85% Fe O and shows a loss on ignition of from 7% to 12%. The remoisturizing of the alumina may be omitted at this point, since the alumina will become saturated with moisture during its incorporation into the tobacco. The moisturized alumina, the moisture being absorbed for example from exposure to daily relative humidities at ambient temperature, shows a loss on ignition of 20.8%, determined by measuring the weight of a sample before and after heating in a furnace at 1000 C. for 1 hour.

The aluminiferous material is incorporated into a sheet of reconstituted tobacco in an amount at least 20% by weight of the tobacco. While regular tobacco can be treated in this manner, it is preferred, for the purpose of the present invention, to employ reconstituted tobacco. The aluminiferous material is thus incorporated into reconstituted tobacco in sheet form and in an amount ranging from about 20% to about by weight, and preferably from about 50% to about 70% by weight. The particular amount selected is influenced by such factors as the general quality of cigarette with respect to taste, mildness, etc., the degree of reduction of tar and nicotine desired, the type of tobacco, the moisture content of the tobacco, the fineness of shredding, types of flavoring and other additives present, and the like.

The aluminiferous material may be incorporated into the tobacco in sheet form with or without the assistance of a binding agent. Where the aluminiferous material is to be incorporated without a binding agent this may be accomplished by using an extract of tobacco and fibers where the latter is derived from either or both of the stems of the fibrous portion of leaf tobacco. Where a binding agent is employed, it may include any suitable type of binding agent such as locust bean gum, guar gum, dextrine, sorbitol, carboxymethylcellulose, and numerous other vegetable or synthetic gums. The amount of binding agent may be varied as desired depending upon the type of binder used.

The effectiveness of the alurniniferous additive materials disclosed above in reducing the tar and nicotine content of cigarettes made in accordance with the methods of this invention is illustrated by a series of tests in which tar and nicotine content were determined in the smoke of various cigarette samples. The smoking was carried out in the testing laboratory in a tour-place solenoid-actuated mechanical smoking machine. Pulfs of 35 inilliter volume and 2 seconds duration were taken at 1 minute intervals until the cigarettes were burned to a predetermined butt length. The cigarettes were conditioned for 24 hours at 77 F. and 50% relative humidity, and the average weight determined. A mark was made on each cigarette to be smoked 23 millimeters from the mouthpiece end of the cigarette and the cigarettes were smoked to this butt length. Fi-ve cigarettes were smoked for each determination. Determinations for both tar and nicotine were carried out in triplicate. The smoking technique was essentially that described in Industrial and Engineering Chemistry, volume 28, pages 836- 839 (1936). This smoke was analyzed by passing it through an absorption train consisting of a Kjeldahl flask containing 1 ml. of 0.5 N hydrochloric acid and ml. of alcohol and thence through 2 bubble traps. The first trap contained 5 ml. of 0.5 N alcoholic hydrochloric acid, and the second trap contained 5 ml. of 0.5 N aqueous hydrochloric acid. At the conclusion of the run the smoke was allowed to settle for minutes. All portions of the smoke collection train were washed into the flask with a minimum of hot water and alcohol. The tar content of the smoke was determined by condensing and collecting it, at ambient room temperature in the absorption train described above. The train was washed with alcohol and water to remove tar condensed in the train and all washings placed in the tar condensate flask. These were transferred to a beaker for evaporation of the solvent and the quantity of tar was determined by complete evaporation of the solvent and weighing of the residue. Nicotine was deter-mined in accordance with the method described in Methods of Analysis of the Association of Oflicial Agricultural Chemists, 8th edition, page 55 (published in 1955 in the United States). The nicotine was steam distilled into dilute hydrochloric acid solution and precipitated with silicotungstic acid. The precipitate was filtered through a Gooch crucible and dried at 105 C. -for 3 hours.

Tests were made for tar and nicotine content of smoke comparing (a) a cigarette with a filler of regular tobacco, serving as a control, and (b) a cigarette with a filler of a tobacco blend of 70% regular tobacco and of reconstituted tobacco containing 60% of activated alumina prepared as described previously in Example 1; and (c) a cigarette with a filler of a second type of regular tobacco serving as a second control, and (d) a cigarette corresponding to cigarette (c) in which about one-third reconstituted tobacco was used together with about two-thirds of tobacco corresponding to type (c) in which the reconstituted tobacco contains 60% of the activated alumina additive previously described in Example 1. The cigarettes were made on regular production cigarette making machines in which the reconstituted tobacco in sheet form was sheared and blended with regular tobacco in the same manner that regular cigarettes are manufactured.

Because in the manufacturing process some of the aluminiferous material is lost in the tumbling and drying processes, the content of the noncombustible additive is determined by comparing the weight of the ash of the control cigarette with that of the additive containing cigarette. This ash data was obtained by igniting the cigarettes at 1000 C. for one hour and revealed that sample (b) actually contained about 12% of the activated alumina and that sample (b) actually contained about 14.9% of activated alumina.

The following results were obtained:

[Unit: mg. per cigarette] Sample; (a) (b) Tar Nicotine Tar Nicotine 30. 7 2.0 20. 2 1. l 31. 0 1. 8 21. 0 l. 2 29. 2 2. 0 l9. 4 1. 2

Average 30. 3 1. 9 20. 2 1. 2

[Unit: mg. per cigarette] Sample (c) a Tar Nicotine Tar Nicotine Average .6 2.8 21.6 1.6

It will be seen from the foregoing tabulation 'of results that in this series of tests the cigarettes of the present invention showed marked reductions in tar and nicotine content of their smoke, as compared with untreated tobacco blends.

The preparation of the tobaccos oontainin g the aluminiferous additive materials of this invention is illustrated by the following examples, but the invention is not to be considered as limited thereto:

Example 2 Since about 50% of the regular tobacco leaves and about 35% of tobacco stems are water soluble, a tobacco extract is prepared by leaching the tobacco leaves and tobacco stems to remove the solubles. The. remaining portion of tobacco leaves and stems is pulped by any desired means, for example, an ordinary rag cutting machine. When the remaining tobacco mass is in very finely divided form, about 60% by Weight of the tobacco mass of activated and tinted alumina is added as prepared in Example 1. The mixture is transferred to a conventional paper making beater and the agitation continued until a uniform distribution and consistency is obtained. The mixture is then made into a wet web on a Fourdrinier type of paper making machine and formed into a thin coherent sheet. This sheet is then passed into a tank containing the prepared tobacco extract which is absorbed to restore approximately the initial tobacco composition, flavor and aroma. The sheet is then dried and shredded to the desired degree of fineness, approximating that of regular shredded tobacco. The dried shredded reconstituted tobacco sheet containing the activated and tinted alumina additive is suitable for blending with regular tobacco to provide cigarette tobacco.

As a modification of Example 2, it is possible to add about from 1% to 5%, preferably 2 /z% of hemp or other strong fibrous material to the tobacco mass prior to the addition of the activated and tinted alumina.

Example 3 Regular tobacco is finely ground until from 20% to 35% would pass through -mesh screen and is suspended in about 50% of water to form a slurry. To this slurry there is added about 5% by weight of the tobacco of locust bean gum ground to approximately the same degree of finenessyand 60% by weight of the tobacco of tinted activated alumina prepared as described in Example 1. The mixture is agitated in a beater until of uniform consistency and composition and formed into a wet sheet which is then dried. The sheet is suitable for blending with regular tobacco after shredding to a suitable particle size.

Example 4 A process for making reconstituted tobacco is set forth in the United States Patent 2,734,510 to G. P. Hungerford et al., which lends itself to carrying out this invention. The process disclosed in this patent broadly comprises forming a wet web from a solution having a film- A tobacco additive was prepared consisting of five parts by weight of activated and tinted alumina as prepared in Example 1 and one part by Weight of a second material consisting of 10.5% by weight of a vanadium pentoxide catalyst and 89.5% by weight of alumina prepared by the Bayer process. This tobaccoadditive is incorporated into a reconstituted sheet of tobacco in the manner set forth in Example 2 so as to contain about 68% additive by weight of the sheet. This reconstituted sheet containing 68% additive was shredded and combined with shredded regular cigarette tobacco to make a cigarette filler containing 30% reconstituted tobacco (containing 68% additive) and 70% regular tobacco. Control cigarettes were prepared using 100% of the same regular cigarette tobacco. All cigarettes were conditioned at nearly 100% relative humidity at 750 F., Weighed individually and selected for testing to fall within :10 mg. weight variation. The tar determination was performed by using the Cambridge filter method described previously by smoking 5 cigarettes to a 23 mm. butt length. The test disclosed an average reduction of tar per cigarette in the additive containing cigarettes of 50.8%.

While the tobacco additives containing an aluminiferous material and aluminiferous materials plus a vanadium pentoxide catalyst have been described as having added to the reconstituted sheet of tobacco by either a paper making process or a film laminate process as in Hunger ford 2,734,510, it is to be understood that the invention is not limited to any particular process for incorporating the tobacco additive.

Although the invention has been described with respect to the incorporation of aluminiferous additives into tobacco fibers, it is to be understood that other vegetable fibers may be substituted .in whole or in part for the tobacco in making smokers articles.

For purposes of this invention, the term finely divided means a dimensional size not substantially greater than the thicknesses of the leaf of regular tobacco which is customarily between .002 inch and .004 inch.

While preferred embodiments of the invention have been described, it is to be understood that the invention is not limited to the specific method and combinations set forth herein, by way of illustration, as it is apparent that many changes and variations may be made therein, by -those skilled in the art, without departure from the spirit of the invention or exceeding the scope of the appended claim.

What we claim is:

Cigarette tobacco comprising a blend of about by weight of regular cigarette tobacco and about 30% by weight of reconstituted tobacco, said reconstituted tobacco having incorporated therein from about 20% to about by weight of a substance selected from the group consisting of heat activated alumina and heat activated bauxite, said substance containing from about 16% to about 26% by weight of moisture releasable by heating at a temperature of about C. and above and having a particle size between about 10 and about 60 microns.

References Cited in the file of this patent UNITED STATES PATENTS 328,300 De Sussini Oct. 13, 1885 1,826,331 Traube Oct. 6, 1931 1,972,718 Sharlit Sept. 4, 1934 2,003,690 Lewton June 4, 1935 2,007,407 Sadtler July 9, 1935 2,063,014 Allen Dec. 8, 1936 2,085,129 Stoemener June 29, 1937 2,108,860 Kaulfman Feb. 22, 1938 2,114,281 Allen Apr. 19, 1938 2,592,554 Frankenburg Apr. 15, 1952 2,613,673 Sartoretto Oct. 14, 1952 2,656,841 Gurley Oct. 27, 1953 2,706,695 Frankenburg Apr. 19, 1955 2,809,637 Hale Oct. 15, 1957 2,887,414 Rosenberg May 19, 1959 2,915,475 Bugosh Dec. 1, 1959 2,933,420 Haden Apr. 19, 1960 2,967,118 Gary June 3, 1961 3,005,732 Specht Oct. 24, 1961 3,011,921 Specht et a1 Dec. 5, 1961 3,034,932 Donovan et al. May 15, 1962 FOREIGN PATENTS 1,060,982 France Apr. 7, 1954 1,115,647 France Jan. 9, 1956 264,287 Switzerland Ian. 3, 1950 OTHER REFERENCES Time, Making Cigarettes Safe, April 22, 1957, page 50.