US3106210A - Smoking tobacco - Google Patents

Description

Oct. 8', 1963 W. G. REYNOLDS ETAL SMOKING TOBACCO Fild Oct. 8,1958

INVENTORS WILLIAM G. REYNOLDS ALEX CYBRIWSKY 3,106,210 SMGKING TOBACCO William G. Reynolds, Anchorage, and Alex Cybriwsky, Louisville, Ky., assiguors to Reynolds Metals Company, Richmond, Va., a corporation of Delaware Filed Set. 8, 1958, Ser. No. 765,963 1 Claim. (Cl. 131-17) This invention relates to novel cigarette and smoking tobacco including a temperature control substance to produce smoke which is cooler, milder, and of greatly reduced nicotine and tar content. The invention also concerns novel cigarettes and tobacco products prepared with such tobacco.

This application is a continuation-in-part of application Serial No. 754,183, filed August 11, 1958, which is in turn a continuation-in-part of application Serial No. 696,900, filed November 18, 1957, both 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 been 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 tobacco 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-occur in the gases produced in the coking of bituminous coal, and hence in the tars obtained by cooling and condensation of coke oven gases. Examples of strongly carcinogenic substances of this type are 3.4-benzpyrene and 1.2.5 .G-dibenzanthracene.

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 including a steroid structure. These sub stances 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 paraffins 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 of the tobacco and/or paper can undergo those chemical transformations and combinations which result in the formation of the aforementioned carcinogenic polycyclic fused ring compounds and possibly 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 pyrolysis are formed chiefly at temperatures above about 800 C.

3,1062 1 0 Patented Oct. 8, 1 963 ice 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, provision of appropriate means for controlling the temperature of the zone in which the distillation products normally undergo chemical transformations and recombination into carcinogenic and tarry compounds will infiuence and greatly diminish the tendency toward formation of such compounds and consequently their presence in the tobacco and cigarette smoke. The general objective can thus be attained of reduction in the amount of carcinogenic material in the vapors drawn into the body of the smoker to a level which no longer presents a substantial cancer hazard.

Control of the combustion characteristics of tobacco and/ or cigarette paper so as to influence the temperature and chemical transformation reactions occurring in the region in which smoke and tar formation is taking place, for the purpose of reducing tar and carcinogen formation, has received little or no practical attention in tobacco processing or cigarette manufacture until the present time.

In accordance with one aspect of the present invention there is incorporated with tobacco a sufficient quantity of a temperature control substance united with water in substantial amounts either chemically or physically, or both, retaining its water content at substantially the same level under all normal conditions of temperature and atmospheric humidity, and which will relinquish said moisture readily, at temperatures from about C. and above. Additionally, the temperature control substance and the products resulting from the substance being burned with tobacco must have the properties of being non-toxic and harmless to the smoker. As used herein the term hydrous refers to the temperature control substance united with a substantial amount of water either physically or chemically. When tobbaco containing the requisite amount of such a hydrous temperature control substance or a mixture of such substances is burned, moisture is released by said substance to control the temperature of the distillation zone adjacent the tobaccos point of burning by reducing this temperature to a level at which the tendency for tars and carcinogenic compounds to form is drastically diminished. In addition the distillation zone temperature is also lowered in proportion to the amount of heat consumed in raising the temperature control substance, including its moisture content, to the burning temperature.

Thus, there is provided in accordance with this invention a novel tobacco mixture incorporating one or more hydrous substances for controlling and influencing temperatures in the zone of smoke formation and embodying new principles and results.

Efforts have been made in the prior art, directed to the incorporation in tobacco or in cigarettes of materials designed to aid combustion by increasing the porosity of the tobacco, or for absorbing moisture generated during the process of combustion. These expedients in fact effectively tend to raise the combustion and smoke forming zone temperature, thereby bringing about an even greater formation of toxic and carcinogenic compounds. It has also been proposed in the prior art to incorporate into tobacco very small quantities of adsorbents, such as silica gel, activated carbon, or ferric oxide to act as carriers for flavoring additives such as menthol or licorice or various flavoring oils, the flavoring material being released therefrom upon heating. These substances are added for this purpose, or as smoke filtration or fixing agents, in very small amounts.

A temperature control substance of the character described, to be added to tobacco within the contemplation of our invention, includes any of a variety or combination of materials, especially aluminiferous material, such as, for example, fluffy alumina, activated alumina, activated bauxite, and crystalline hydrated alumina. These substances all either contain or are capable of uniting or holding substantial amounts of sorbed water which they readily release when exposed to heat. All are non-toxic and relatively stable under ordinary temperature and humidity.

in accordance with our invention, the aforementioned substances, in a state in which they contain large amounts of heat-releasable sorbed water, whether bound physically or chemically, are incorporated into tobacco in such proportions, relative to the weight of the tobacco, that a substantial portion of the heat evolved in the combustion of the tobacco will be utilized in liberating and vaporizing the water content and in heating the control substance and its water content to the combustion temperature.

Further, we have discovered a new and special form of temperature control substance, designated. herein as fluffy temperature control substance, and the method of preparation of the same. The new type of temperature control substance is light and somewhat fluffy in texture and appearance, more porous, more moisture absorptive, and about two times li hter than the temperature control substance from which it is made. It is especially adapted for incorporation into tobacco wherein the combustion of the adhesive binder admixed with the particles enables the temperature control substance to dissipate into powder with the cigarette or tobacco ashes after burning, a feature of commercial importance. In order to prepare the new fluffy temperature control substance, finely divided ordinary temperature control substance such as activated alumina or activated bauxite, or a combination of two or more of these or other materials are reconstituted by treatment with a nontoxic adhesive which is capable of losing its adhesiveness at the burning temperature of the tobacco, permitting the alumina or bauxite to disperse. Thus, for example, activated alumina or activated bauxite, having a particle size between about 50 and 200 mesh, is admixed with a suitable gum adhesive, such as a vegetable or synthetic gum, for example gum arabic or gum tragacanth, in an amount ranging from about 5 to percent by weight of the temperature control substance. The mixture, after exposure to moisture for a suitable period, followed by air drying, may be comminuted to about 14 to 40 mesh size, and then exposed again to moisture, the moisture content thereby rising to about 18 to 22 percent.

In accordance with an alternative method of preparation, the starting material, such as activated bauxite or activated alumina, is mixed with a solution of gum arabic, separated by decantation or filtration, and then dried to a powder having the desired water content. Also, the fiulfy temperature control substance may be made less dense by aerating it during its manufacture, such as by stirring or blowing air bubbles into it or incorporating a small amount of a material which liberates or changes to a gas.

*If the starting material is not of a desired color it can be dyed with a brown tinting agent to match tobacco shades, such as, for example, in the case of activated alumina, by spraying or immersion, in a solution of ferric ammonium oxalate, having a concentration between about 0.5 and 10%, for example, g. per liter, at a temperature of about 140 'F., for a period of about 2 to 5 minutes. The dyed alumina is separated and air dried to the desired moisture content. Then from about 5 to 10 percent by weight of dry natural gum, such as gum arabic or gum tragacanth, is added to the dry tinted alumina powder, and thoroughly mixed therewith until uniform. The mixture of alumina and gum is exposed to moisture and dried while mixing. The gum thereby acquires adhesive properties and acts as a binder for the small alumina particles. The mixture is then air dried and any large particles are reduced to smaller desired size ranges, for example 14 to 28 mesh. Alternatively, the alumina or other materials can be tinted by admixing therewith a small amount, about 0.5 to 2 percent of bauxite which, because of its impurities, principally iron oxide, is naturally of a suitable color. Or, if desired, a solution of a suitable brown organic dye may be employed for this purpose, such as, for example, Gold C (Sandoz) which is a mixture of metallized monoazo dyestuffs.

The new fluffy temperature control substance thus prepared can be more readily admixed with ordinary tobacco, from which it does not tend to separate. Upon exposure to heat, such as that generated in the combustion of tobacco, the gum arabic or other gum loses its adhesive properties and the hydrous temperature control substance particles readily are dispersible to a fine powder.

Many temperature control substances as defined herein may be utilized for admixtures with tobacco in accordance with our invention and include various other moisture-sorbing forms of alumina. Thus, activated alumina, which is essentially a mixture of various crystalline forms of aluminum oxide, is a material having a low density and a large surface area per unit weight and a highly porous structure. It is produced by heating alumina hydrate to a temperature sufiicient to drive off most of the combined water, but is capable of absorbing from 16% to 20 additional moisture, depending upon the relative humidity of the moisture atmosphere to which it is exposed. In forming activated alumina, the alumina hydrate should not be heated so high as to produce any significant amounts of gamma or alpha alumina, which usually begin to form at temperatures above about 850 C. The moisture absorbed by the activated alumina is readily releasable at temperatures as low as about 165 C. In accordance with this invention, hydrous activated alumina of the character described may be incorporated as such or in fluify form into tobacco to control temperature of the combustion products by release of sorbed Water upon exposure to heat, and by absorption of heat required to raise it and its water content to the combustion temperature.

As an alternative to activated alumina, there can be used as a temperature control substance, in accordance with our invention, activated bauxite. This is prepared from bauxite in a similar manner as 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 the oxides of iron and other impurities. The activated form can have a residual moisture content as low as about 2 percent. It can be hydrated up to about 2-6 percent moisture content, this sorbed moisture being releasable upon heating.

Alumina trihydrate (Al O' .3H O) is a dry, free flowing crystalline powder, produced from dry process sodium aluminate, and containing about 50% moisture based on A1 0 content which is readily releasable upon heating to temperatures of 110 C. and above.

Temperature control substances such as the foregoing substances, or mixtures thereof, united with water, in accordance with this invention, are incorporated into tobacco in amounts at least 20 by weight of the tobacco, but advantageously ranging from approximately 20% to about by weight of the tobacco, and preferably in an amount ranging from about one part by weight to four parts of tobacco (251% of the weight of the tobacco) to one part to two parts of tobacco (50% of the weight of the tobacco). The precise amount to be added is influenced by such factors as the type of temperature control substance, type of tobacco, moisture content of the tobacco, degree of shredding, the cigarette paper used, types of flavoring and other additives present, and the like. It appears that the quantity of hydrous temperature control substance present is such that in addition to moisture 'release, a substantial filtering action by the alumina parr ticles, both hydrated and dehydrated, is available to the smoker.

If the control substance is used without a binder, the particles should not be so small as to result in substantial loss or maldistribution of the substance through sifting or change of position between the tobacco particles. As an example, 14 to 28 mesh particle size of the control substance has been found generally satisfactory. If a binder is used, it is possible and preferable to utilize the smaller sizes, for example from 50 to 200 mesh, and down to 325 mesh and below. Any suitable binding agent may be used, such as, for example, dextrin, sorbitol, carboxymethylcellulose, vegetable or synthetic gums, or the like. The amount of binder may be varied as desired; for example, it may range from about 1 to 5 percent or more by weight of the tobacco, depending on the binder used.

Further, a temperature control substance such as activated alumina, activated bauxite, or hydrated alumina may be incorporated into cigarette paper in amounts sufficient to control and lower the temperature of the smoke forming zone adjacent the cigarette combustion zone, to minimize the formation of tars and/ or carcinogenic products which may result from combustion of the paper. Such additions of these various types of alumina may be made, for example, at the beater stage before the paper fiber slurry is formed into sheets on the Four-drinier machine. The amounts of alumina added will generally range from about 5 to percent, the amounts added being selected so as to impart to the paper a combustion rate no greater than that of the tobacco-alumina mixture, when used in cigarettes in conjunction therewith.

Additionally, tobacco combined as described with the hydrous temperature control substances, is made into cigarettes using as a Wrapper therefor, cigarette paper which has incorporated therewith an ash strengthening material such as being coated with a thin layer of aluminous metal, or with a layer of aluminum oxide, or a mixture of aluminous metal and oxide (partially oxidized aluminum) on one or both' sides of the paper. It has been found that in some cases there is a problem of hot particles of ash dropping from the cigarette during burning and this problem is substantially solved and such dropping eliminated by using cigarette paper coated on one side with a thin layer of aluminum or aluminum oxide, or a mixture thereof. The thickness of the coating will be of the order of a few millionths of an inch. Such metal coated cigarette paper may be manufactured by known methods, for example, by deposition of metal on the surface thereof using vacuum metallizing procedures. Regular cigarette paper may be coated on one side in this way using a vacuum below 1 micron pressure with a single flash of aluminum to provide an aluminum metal layer of a thickness between about 3 and millionths of an inch, preferably about 5 to 10 millionths of an inch. When the metallization is carried out at low pressures between about 2 and 5 microns, there is formed on the paper a yellowish coating, attributable to the formation of aluminum oxide on the surface of the metal by oxidation due to small amounts of residual oxygen in the vacuum chamber. Using about 30 microns pressure aluminum oxide is deposited with a light brown to dark violet color. The coating of aluminum oxide or of aluminum metal in combination with the oxide is superior to that of aluminum metal itself insofar as the combustion of the paper is concerned, since the greater the proportion of oxide, the lower is the temperature rise, small under any circumstances, which results from the combustion of the metal. Thus, the oxide coating on the paper produces a temperature lowering effect similar to that of the alumina in the tobacco, except that no release of moisture is involved.

Cigarettes prepared from the tobacco treated with the temperature control substances of this invention and made into cigarettes using the above coated paper exhibit improved ash retention and ash stability, in that ash and hot particles do not drop off immediately after burning, but remain in place until a substantial length has been formed. This ash strengthening is caused by the burned special cigarette paper leaving an envelope-like outer layer which efiicaciously improves the stability and retention of the ash. A cigarette prepared using tobacco admixed with fluffy alumina as a filler, and aluminized cigarette paper shows especially favorable ash strength.

Other means for treating the cigarette paper so as to give it ash strengthening characteristics have also been discovered. For example, aluminum powder, minus 400 mesh, is suspended in the amount of 5 to 25 percent in a 0.1 to 1 percent water solution of methylcellulose. This solution is applied to one side of cigarette paper by brushing on or rolling on techniques. After drying a thin fairly uniform aluminum coating adherent .to the cigaretite paper is obtained. Other binders than methylcellulose, such as vegetable gums, may be used for the same purpose. When smoking a cigarette made with this type of aluminum coated paper, an envelope forms around the ash during burning so that the hot particles do not drop readily but are retained until a substantial length of ash is formed.

Although a coating of aluminum or aluminum oxide or combination thereof is preferred, the cigarette paper can also be treated in a solution containing a small percentage of a so-called flame proofing agent, for exarnple, a 1 to 5 percent solution of a sodium bzorophosphate complex known commercially as Abopon (Glycol Products "Compan New York City, United States of America). The envelope is black in color and is capable of retaining ash with hot aluminapanticles until tipped off. The cigarette paper loses some flexibility and may tear during wrapping; accordingly, treatment with a flame proofing agent is preferably carried out after the cigarette is made.

The hydrous temperature control substances of our invention may be incorporated into cigarette and smoking tobaccos of all types, at any desired stage of processing. Thus, in the case of cigarette tobacco, the substance may be applied to the leaf prior to cutting, or to shredded tobacco.

Our invention is also readily applied to the improvement of so-called reconstituted tobacco, prepared from waste fines, field scrap '(fann damaged leaves), stems, and dust, which are customarily cut or comminuted and formed into sheets with the aid of a suitable binding material, and afterward made into filaments by shredding, or into strips, for the preparation of smokers articles such as cigarettes, cigars, and the like. The control sub-= stance may be incorporated into the sheet ingredients.

The control substances may also be made into a thin sheet using a suitable binder, and then the sheet shredded into thin individual fibers which may be incorporated into the tobacco.

Suitable flavoring materials, humectants, and the like, may be admixed with the control substance as well as with the tobacco itself.

In the accompanying drawing, the single FIGURE illustrates a cigarette prepared in accordance with this invention.

The novel cigarette, =10 in the preferred embodiment shown, comprises a wrapper 14, of cigarette paper hearing on the inside surface thereof a thin layer '18 of metallic aluminum, aluminum oxide or a combination thereof, and a filler 12 composed of a mixture of cigarette tobacco and hydrous fiulfy alumina. Preferably, but not essentially, a filter 16 is included in the body of the cigarette.

The effectiveness of the hydrous temperature control substances disclosed above in reducing the tar and nicetine content of cigarettes made in accordance with the preferred embodiment of this invention, is illustrated by a series of tests in which tar and nicotine content were determined in the smoke of various samples of cigarettes. The smoking was carried out in the testing laboratory in a four-place solenoid-actuated mechanical smoking Inachinc. Pufis of 35 milliliter 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 at 25 C. and 50 percent 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. Five cigarettes were smoked for each single 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 836839 (published in 19 36 in the United States of America). The smoke was analyzed by passing 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 absonptiontrain 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 solvent and weighing of the residue. Nicotine was determined in accordance with the method described in Methods of Analysis of the Association of Official Agricultural Chemlists, 8th edition, page 55 (published in 1955 in the United States of America). 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.

In tests comparing (a) a cigarette with a filler of tobacco blend admixed with 35% by weight of the tobacco of hydrous fiuiiy alumina, and (b) a control cigarette containing the same weight of the same tobacco blend with no additive; and (c) a cigarette with a filler containing 33 /3 alumina trihydrate by weight of the tobacco, and (d) a corresponding cigarette with the same weight of the same tobacco with no additive, the following results were obtained:

[Unitz mg. per cigarette] t willbe 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 8 content of their smoke, as compared with untreated cigarettes, using the same tobacco blend.

In a second series of tests, with smoking and analyses conducted as previously described, cigarettes of a brand reputably having one of the most eflicien-t filters were purchased on the open market. In order to prepare a single sample test cigarette, the filter was broken, the paper split from the tobacco, the tobacco and the filter placed in a king-size hand operated apron cigarette maker. A measured charge of hydrous fiuiiy alumina or hydrous activated alumina was sprinkled evenly over the tobacco and worked into the tobacco with a stylus. A gummed cigarette paper was set into the roller and the cigarette containing the alumina reassembled and marked. Samples were marked A, B, C, D, and E, as follows: A (lib ter), 1 part coarse while hydrous activated alumina to 5 parts tobacco; B (filter), 1 part tinted hydrous flufiy activated alumina to 5 parts tobacco; C (filter), 1 part tinted coarse hydrous activated alumina to 4 parts of tobacco; D (filter), 1 part tinted hydrous fluffy activated alumina to 2 parts of tobacco; and E (filter), commercial cigarette reassembled as above with filter, but with no alumina additive. Three runs were made, for each cigarette.

The results obtained were as follows. All values are in milligrams of tar in the smoke of one cigarette:

Sample A 13 O D E Run 1 13. 9 14. 4 15. 2 8. 8 19. 7 Run 2 12.6 10.3 13.9 9.3 18.9 Run 3 13.6 17.4 16.2 10.8 19.3

Average 13.4 16. 0 15.1 9. 6 19. 3

It is apparent from the above tests that cigarettes containing tobacco treated in accordance with this invention exhibited substantially lower smoke tar content than did the commercial cigarette and it appears that the filter action of the filter itself is substantially improved.

The practice of the present invention may be illustrated by the following examples without, however, being considered as limited thereto.

Example 1 There is added to cut cigarette tobacco about 50% by weight of 14 to 28 mesh fiuiiy activated alumina containing about 24% total moisture based on the A1 0 conent. This additive is preferably made to the tobacco in the cigarette machine just prior to the tobacco being formed into a cigarette.

Example 2 Tobacco Waste suitable for manufacturing reconstituted tobacco is made into a water slurry which contains a suitable binder and to which is added an amount of alumina trihydrate equivalent to about 25 to 50% of the air dry weight of the tobacco. When air dry, tobacco contains about 12.5% moisture. This slurry is formed into a sheet in accordance with conventional procedures.

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 forming material dispersed therein. Dry tobacco dust is applied in a uniform layer to the wet web which is subsequently dried and shredded or cut for use as a tobacco product. The Hungerford process is utilized in carrying out the present invention by applying, in conjunction with the tobacco dust as it is applied to the wet web, alumina trihydrate of 325 mesh size and smaller in an amount such as the air dried reconstituted tobacco will contain from 25 to 50% of the trihydrate.

Example 5 The above outlined Hungerford'process can also be utilized in making a flexible Web of the temperature control substance. This is accomplished by dusting hydrous activated alumina in place of the tobacco dust onto the wet web followed by treating the dusted web in accordance with the remaining steps of the Hungerford process. The resultant sheet product is then shredded and added to shredded tobacco in an amount equivalent to a hydrous activated alumina content varying from 25 to 50% by weight of the tobacco.

Example 6 Reconstituted tobacco having a temperature control agent such as hydrous activated alumina or alumina trihydrate incorporated therein, as set forth in Examplm 4 and 5, is rolled by conventional methods into a thin sheet suitable for use as a cigarette paper or wrapper.

Example .7

A cigarette was prepared using ordinary cigarette paper and as a filled tobacco admixed with about 35 percent of hydrous flulry alumina prepared as described above. The effect of the lower smoke forming temperature of the tobacco is demonstrated by laboratory tests in which the cigarette, and an ordinary cigarette were first conditioned at 77 F. and 50% relative humidity, and each was smoked as aforementioned .on a standard smoking machine as described in Industrial and Engineering Chemistry, volume 28, pages 836-839 (1936). The smoke was passed through an absorption train and analyzed for tar and nicotine content in accordance with standard methods. An average of three runs showed an average nicotine and 31.3 mg. tar in the smoke of the cigarette using cordance with this example of 1.6 mg., and a tar content of 22.7 mg. as compared with an average of 2.4 mg. nicotine and 31.3 mg. tar in the smoke of the cigarette using ordinary tobacco.

Example 8 A cigarette was prepared using as a filler tobacco mixed with alumina having a particle size of about 200 mesh admixed with gum arabic binder and containing 20% moisture. As a wrapper there was employed a cigarette paper carrying an inside coating of aluminum applied by 10 vacuum metallizing to a thickness of about 5 millionths of an inch. The cigarette showed good burning characteristics and burning power, cooler taste and good ash retention.

Throughout the above description the term mesh is used as a measure or" the particle size of the granular substances. The mesh size corresponds to the number of openings per linear inch in a sieve. For example, 14 mesh means a particle size that will just manage to pass through an opening in a sieve which has 14 openings per linear inch and 196 openings per square While preferred embodiments of the invention have been shown and described, it is to be understood that the inventors are not confined to the specific methods and compositions herein set forth, by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claim.

What we claim is: 7

Smoking tobacco having incorporated therein from about 25% to about 50% by weight of the tobacco of a substance selected from the group consisting of heat activated alumina and heat activated bauxite, said substance containing rrom 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 50' and about 200 mesh.

References Cited in the file of this patent UNITED STATES PATENTS 1,972,718 Shar-lit Sept. 4, 1934 2,003,690 Lewton June 4, 1935 2,007,407 Sadtlcr July 9, 1935 2,108,860 Kaufman Feb. 22, 1938 2,114,281 Allin Apr. 19, 1938 2,460,285 Hale Feb. 1, 1949 2,592,554 Frankenburg Apr. 15, 1952 2,613,673 Sartioretto et al. Oct. 14, 1952 2,698,305 Plank et al. Dec. 28, 1954 2,706,695 Frankenburg Apr. 19, 1955 2,933,420 Hadin Apr. 19, 1960 2,955,060 North Oct. 4, 1960 2,967,118 Gary et al. Jan. 3, 1961 2,976,190 Meyer Mar. 21, 1961 3,034,932 Donovan et al May 15, 1962 FOREIGN PATENTS 1,114,764 France Dec. 19, 1955 838,419 Germany May 8, 1962 OTHER REFERENCES Ser. No. 261,049, Lande (A.P.C.), published May 11, 1943.

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