Document By4p1m6qxbjNqRxG8nBMB3bOo

FILE NAME: Reynolds Metal (RM) DATE: 1962 DOC#: RM 104 DOCUMENT DESCRIPTION: Patent for Adding Asbestos to Tobacco Nov. 12, 1968 B. F. A R M B R U S T , JR.. E T A L TOBACCO COMPOSITION Filed July 28, 1965 3,410,276 P /sS a /zte 6 /& reffe p p s/zerf -/vzm r/ 7% BY V INVENTORS ATTORNEYS U nited States Patent O ffice Patented Nov3.,41120, ,1297668 1 2 from the nature of the substance. There also might be 3,410,276 produced simultaneously polycyclic aromatic compounds TOBACCO COMPOSITION Bernard F. Armbrust, Jr., Benton, and Val G. Carithers, which are known to exert an anticarcinogentic action on known carcinogenic polycyclic compounds of similar Little Rock, Ark., assignors to Reynolds Metals Com pany, Richmond, Va., a corporation of Delaware 5 chemical structure. Thus, the tendency toward formation Continuation-in-part of abandoned application Ser. No. of harmful products in the smoke can be favorably in 372,305, June 3,1964. This application July 28,1965, fluenced. Ser. No. 475,331 Methods have been proposed in the prior art, whereby 9 Claims. (Cl. 131--9) there are added to tobacco in order to influence its com 10 bustion temperature characteristics, the oxides, hydroxides, and carbonates of alkaline earth metals, or of magnesium, ABSTRACT OF THE DISCLOSURE or of aluminum. Of these additives, the most efficient appears to be aluminum oxide, particularly in the form Tobacco is mixed with about 5 to 35 percent by of its various hydrates. The hydrates of aluminum oxide, weight of a shredded sheet material made of a tempera 15 such as, for example, alumina trihydrate and bauxites ture control substance (such as alumina hydrate), a which contain up to 75% or more alumina hydrates, are fibrous matrix material such as asbestos, and a vegeta capable of releasing their united water at temperatures ble gum binder (such as guar gum). The additive has a starting at about 150 C., and it has been proposed to uti lowering influence on peak temperature and firms the lize this characteristic by incorporating in tobacco such ash when the tobacco is smoked. The shredded sheet 20 alumina hydrates and activated aluminas containing ad may have rough exposed surfaces providing internal sorbed water, as disclosed, for example in Patents 3,106,- filtration of the smoke. 210 and 3,106,211. These aluminas are 'all nontoxic and relatively stable under ordinary conditions o f tempera ture and humidity. They all contain definite amounts of This application is a continuation-in-part o f copend- 25 sorbed or combined water which are readily releasable ing application Ser. N o. 372,305, filed June 3, 1964, when the aluminas are exposed to heat. In Patent 3,106,210 now abandoned. there is further disclosed a fluffy form o f alumina or This invention relates to novel cigarette and smoking bauxite wherein the finely divided material is admixed tobacco having incorporated therein a combustion tem with a vegetable or synthetic gum binder to promote ad perature control material in the form of a shredded 30 hesion of the alumina particles to each other. sheet. More particularly, the invention concerns ciga Among the requirements for a material of this tem rettes and tobacco products incorporating said novel perature control type is that the alumina and/or other tobacco, which upon smoking, reduces the formation substance be distributed among the tobacco particles so of harmful substances while improving the smoking intimately and uniformly that the temperature of the flavor thereof. 35 mixture is uniformly and effectively controlled during During the past several years, there has been exten smoking and that it will produce a strong ash from which sive discussion in medical and public health circles con the alumina and/or other additive will not seperate to cerning the alleged carcinogenic and other harmful ef an objectionable degree during the smoking process. Finely fects of cigaretees and other smokers' articles. This dis divided alumina has the tendency to segregate from its cussion has recently been supplemented by the report 40 admixture with the tobacco, settling to the bottom of the of the Surgeon General of the United States, confirm cigarette, causing uneven burning. In addition, the pow ing that statistical evidence tends to show a higher in dery aditives tend to sift out of the cigarette when it is cidence of throat cancer and lung cancer in the case of handled an especially when it is tapped. Most importantly, smokers, and especially cigarette smokers, than is true a coherent ash is not formed, but instead the ash tends of non-smokers. These carcinogenic effects are usually 45 to flow off. This can, of course, largely nullify the effective ascribed to the presence in cigarette smoke of certain ness and the acceptability of a finely divided additive. polycyclic aromatic hydrocarbon compounds contain In accordance with the present invention, the afore ing fused ring structures. Experimental studies have in mentioned disadvantages of segregation of the additive dicated that the carcincogenic compounds resulting from from the tobacco and the undesirable flow o f ash, are tobacco pyrolysis are formed chiefly at temperatures 50 avoided by incorporating a novel combustion control above about 800 C. Below about 700 C., relatively additive with the tobacco in a wholly novel manner. small amounts are formed, and at about 600 C. and In accordance with the invention, there is employed below, no aromatic polycyclic compounds are found in for incorporation with the tobacco a shredded sheet which the pyrolysis products. may be processed like the leaf tobacco in most steps in It is known that the smoking process is a complicated 55 tobacco and cigarette manufacture. The shredded sheet one and includes both pyrolysis and combustion, and that additive of the invention comprises a temperature con in every material pyrolyzed, whether tobacco or paper, trol substance, a fibrous matrix, and a small amount of there is a temperature at which the maximum amount organic binder. This sheet and its preparation are de of polycyclic compound is formed, so that as tempera scribed in copending application Ser. No. 372,369, filed ture increases, the formation of polycyclic compounds 60 June 3, 1964. increases up to a certain point, after which the formation The temperature control substance employed as a com decreases. Some of the pyrolytic products which formed ponent of the shredded sheet additive of the invention during the combustion process are subsequently burned is selected so as to be more or less effective in cooling in situ after being formed, a result which is influenced to enhance taste and other desired characteristics of the to some extent by the peak temperatures reached, but 05 burning cigarette. Among the more effective cooling the net presence of harmful substances in the smoke is agents are those compounds which have large proportions the result of the total smoking process and not the result of hydration or of volatile nontoxic anions, such as car of peak temperatures alone. Thus there is presented the bonates or which possess large heat demand for phase possibility of incorporating in the tobacco a substance transformations. These compounds must, of course, not by means of which the rate of combustion of the tobacco 70 be inimical to flavor nor must they generate obnoxious can be controlled with concomitant lowering o f distilla or undesirable fumes when exposed to temperatures up to tion temperature and perhaps some catalytic response 800 C. The greatest heat demand should be preferably 3 ,4 1 0 ,2 7 6 3 4 in the range 200 to 600 C. in order to cool the critical adsorbed strongly and rapidly on smoke particles, leading destructive distillation zone of the cigarette most effec to the current belief that polonium in cigarette smoke tively. may act as an important initiator in the development of The temperature control substance selected in accord lung cancer. Polonium as an alpha radiation emitter is ance with the invention may thus include an oxide, hy 5 considered very hazardous, presenting a definite inhala droxide, or carbonate, or a hydrated form thereof, of tion danger as a potential lung carcinogen in an insoluble an alkaline earth metal, or of magnesium, or of aluminum form of appropriate particle size, approximately 1 micron. or other cation which is nonvolatile under the burning Published data (Science, vol. 143, page 247), have shown conditions. There may also be employed hydrated min that a forty cigarette a day smoker may develop localized erals capable of giving off their contained water upon 10 polonium-210 concentration o f up to 1000 rem in various heating, such as various clays. regions of the bronchial tree over a 25 year period. These temperature control substances are prepared in Dosages of 1300 rem over a 25 year period can cause sheet form by admixing a major proportion of a tempera lung carcinoma. A rem is a measure of the radiation ture control substance o f the character described with a damage done to living tissue and is dependent on the minor proportion o f a fibrous matrix material, and a 15 concentration and disintegration rate of the radioactive small amount of a binder. The dry mixture is made into element as well as the energy o f the emitted particles. a viscous slurry with water, and the slurry is placed on Thus, the literature indicates that for polonium-210, 0.033 an impervious, chemically inert and nonadherent surface picocuries per square centimeter dosage would be equiv provided with a retaining edge, dried, and the resulting alent to 165 rem over a 25 year period. sheet is stripped off. 20 A s shown in the test data of Table 4, below, the in The preferred temperature control substance, in ac clusion of alumina as an additive in cigarettes reduced cordance with the invention, is a hydrate o f alumina the polonium in the smoke from cigarettes that would be which is capable of releasing its sorbed or combined taken into the lungs by about 40%. Thus, localized con water upon heating. Thus, there may be employed the centrations o f the polonium due to smoke from cigarettes crystalline hydrates o f alumina represented by the for 25 containing the alumina additive of the invention would mulas AI2O3.3H2O or A l(O H )3. These are dry, free-flow be reduced to a value well below the 1300 rem considered ing white crystalline products available in abundance to be dangerous for persons smoking two packs o f ciga from the Bayer, or Bayer-sinter process. The combined rettes a day. water is releasable on heating starting at about 150 C. The fibrous matrix material is composed of inorganic Instead of hydrated alumina, there may be employed 30 fibers, examples o f which include asbestos, or a ceramic activated alumina, which is defined as essentially a mix fiber made from alumina and silica sold under the desig ture of various transition phases o f aluminum oxide, such nation "Fiberfrax" (Carborundum Co., Niagara Falls, as gamma, eta, and the like, usually with boehmite N .Y .), or glass wool. The fiber must be "opened up" and (AI2O3.H2O ). Activated alumina is a material having a dispersed before use. Asbestos, for example, comprises large surface area per unit o f weight, and a highly porous 35 fibers closely stacked together, and these must be sepa structure. It is produced by heating alumina hydrate to rated, for example, by dry or wet hammermill separation. a temperature sufficient to drive off the great preponder For maximum effectiveness, the fibers must be treated so ance o f combined water. It is capable o f adsorbing from that they are reasonably separate with sufficiently rough or about 16% to about 2 0% o f additional moisture, de fibrilated surfaces to make a satisfactory bond (aided by a pending upon the relative humidity of the atmosphere to 40 binder) with each other and with the temperature control which it is exposed. The adsorbed moisture is readily and rapidly releasable at the elevated temperature which oc substance to give good sheet strength. The fibers should also not be so long as to be difficult curs in the burning of a cigarette. As an alternative to activated alumina, there can also be employed activated to control with a doctor blade in feeding the slurry into which they are subsequently formed onto the drying belt bauxite, which is prepared from bauxite aluminum ore in 45 or other device. The fibers should not be so short as to a manner similar to that by which activated alumina is be incapable of effective bonding. In general, a length of prepared from alumina hydrate, and it has similar prop about V4" to about Vi" is satisfactory. erties. Where asbestos is employed, it is preferably a hydrous Activated alumina has the additional advantage of magnesium silicate o f the tubular fiber type, an example being an adsorbent like carbon for volatile compounds 50 o f which is chrysotile asbestos, having the approximate other than water. It can thus selectively trap components formula 3M g0.2S i02. This material has a fibrous crystal o f smoke capable o f entering its pores. Its use as a structure and a silky luster, is white in color, and exhibits catalyst or catalyst base is well known, thereby providing very good tensile strength. There may also be employed yet another modifier of the components o f cigarette crocidolite type asbestos, which is a complex sodium-iron smoke. It should be further noted that the alumina tri 55 silicate, also possessing high tensile strength, and a laven hydrates convert to activated alumina in the course of der color. exposure to heat, thus combining the greater cooling The organic binder may be a natural or synthetic gum, power of the trihydrate with many o f the benefits o f the term as employed herein including, for example, vege activated alumina. table gums, such as gum arabic, gum tragacanth, and In addition to the foregoing advantages, alumina and 60 other water soluble gums, which consist largely of carbo alumina hydrates possess another outstanding advantage hydrates and are hydrophilic colloids. There may also be as additives to smoking tobacco, which is wholly sur employed synthetic gums, such as dextrin, and various prising and unexpected. This is the ability o f these sub cellulose ethers, such as, for example, methylcellulose stances to reduce to a very low level in the gaseous com or hydroxypropylcellulose. These are obtainable in aque bustion products o f the tobacco, radioactive elements of 65 ous solution, the methylcellulose solution having a vis the type which emit alpha radiation, such as polonium. It has been known for some time that tobacco leaves cosity of about 4000 centipoises, while the solution o f the contain minute amounts of the element polonium-210, hydroxypropylcellulose has a viscosity o f about 15,000 an alpha-emitting radioactive element, which vaporizes at centipoises. about 500 C., or substantially below the combustion 70 Where a vegetable gum is employed as a binder for the temperature of a cigarette, which is in the range 800 to temperature control substance in the sheet o f the inven 900 C. The element polonium (Po) possesses 24 iso tion, it is preferably a polysaccharide type, such as, for topes, ranging in mass from 197 to 218, all of which are example, guar gum, derived from the seeds o f Cyamopsis radioactive. The most common form is Po210 which has tetragonobolus, which exhibits a high degree o f water a half-life of 138.4 days. Polonium is capable o f being 75 dispersibility and thickening power. Thus, there can be 3,410,276 5 6 employed the product sold under the designation Burtonite The second type sheet is generally stronger and, before N o. 78 (The Burtonite Company, Nutley, N .J.). mixing with tobacco, should be broken into shreds and A small amount of a plasticizer, namely from about pieces not exceeding %" in length to avoid a rough-look 1% to about 5% by weight, is advantageously incorpo ing ash from long shreds. rated in the temperature control substance sheet mixture 5 The second type sheet with asbestos fiber can be con to improve sheet flexibility. The plasticizer is advantage verted to provide internal filtration and tar reduction like ously a polyhydric alcohol, such as, for example, glycerol, the first type sheet by beating the second type sheet suf or a glycol, such as ethylene glycol or propylene glycol. ficiently to expose the asbestos fibers in the sheet. The The foregoing ingredients are preferably employed in shreds and pieces, of course, will be somewhat smaller the following proportions: 10 than the broken pieces o f the second type sheet that would Percent by weight not have internal filtration. Temperature control substance, e.g., alumina tri The temperature control substance sheet is admixed hydrate ____________________________________ 75-95 Fibrous matrix material________________________ 3-15 Vegetable gum binder__________________________ P lasticizer____________________________________ 1-5 15 1-5 These ingredients are admixed with water in an amount from about 5 to about 20 times by weight o f total solids, made into a viscous slurry in any suitable type o f mixer and dried at a temperature below that at which the tem 20 perature control substance begins to release its own water. Some fibrous materials are improved in effectiveness by vigorous shearing action to fibrillate them, as in a blender, Jordan, etc. Some gums require heat and agitation to dis solve, but heat degradation should be avoided. 25 A preferred composition for the sheet of the invention is, by weight: Percent Alumina trihydrate _____________________________ 85.0 A sb esto s________________________________________ 8.5 30 with the tobacco in a proportion ranging from about 5% to about 35% by weight o f the tobacco, preferably about 10% to 25%. The sheet may be mixed with either regular tobacco or with reconstituted tobacco. For the purposes o f this invention the term reconstituted tobacco refers to tobacco particles or 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 into sheets and afterward converted to fila ments by shredding, or into strips, for the preparation of cigars, cigarettes, and the like. Suitable flavoring materials, humectants, and the like, may be admixed with the control substance as well as with the tobacco itself. The following examples illustrate the practice of the invention, but are not to be regarded as limiting. Example 1.-- Internal filtering sheet Guar gum_______________________________________ 4.2 P la stic iz e r ______________________________________ 2.3 20 grams of alumina trihydrate having a fineness such that approximately 90% is minus 325 mesh, and averag The particle size o f the temperature control substance ing about 25 microns in diameter, is admixed with 2 is not critical, but particles should preferably be finer than 35 grams of chrysotile asbestos fibers, 1 ml. of glycerol and 325 mesh to avoid rough surfaces that tend to powder 1 gram of guar gum binder (Burtonite N o. 7 8). The mix and that make the sheet less strong. Thus, where alumina ture is made into a viscous slurry with 300 ml. water. The trihydrate is employed, the average particle size may be slurry is spread on a sheet of polytetrafluoroethylene about 25 microns. (Teflon) plastic provided with retaining edges, and placed Some o f the combustion control substances disclosed 40 in an oven at 100 C. until dry. The sheet is stripped off are normally white or nearly white in color, and thus and cut into shreds like cigarette tobacco. may present some difficulty with respect to inconspicuous The shredded particles are admixed in a blender with blending into the tobacco. It has been found that this tobacco in the proportion of 0.25 grams o f sheet per 0.75 difficulty may be overcome by incorporating in the control grams of tobacco, to yield a mixture which is combustible, substance an inorganic or organic dye compound which 45 and this mixture was made into cigarettes. will stain the sheet product any desired yellow to brown tint. Thus, ferric hydroxide obtainable, for example, by reacting ferric ammonium oxalate with ammonium hydroxide may be added to the alumina-asbestos-binder- Example 2 Proceeding as in Example 1, a sheet was prepared from the following ingredients: plasticizer slurry in the amount desired to produce the 50 Alumina trihydrate ____________________ grams__ 20 required color in the dried sheet made therefrom. Glass w o o l ______________________________do___ 2 The finished alumina fibrous matrix thin sheet con B u rto n ite-7 8 _____________________________do___ 1 taining a binder is quite flexible, but the small amounts G ly cero l__________________ .______________do____ 0.5 of glycerine or other plasticizing materials serve to Water ____________________________________ ml__ 100 increase the flexibility. 55 This sheet was shredded and admixed with tobacco in There are two types of sheet useful in this invention. the proportion o f 0.25 gram sheet to 0.75 gram tobacco. The first type sheet, which contains asbestos fiber, evi Example 3 dences reduction in tar of smoke plus temperature control 2000 lbs. o f an aqueous slurry o f alumina hydrate, as of the critical distillation zone. The surface of the sheet bestos and guar gum containing about 10% solids were is rough with asbestos fibers exposed and these provide 60 prepared from: internal filtration. Sheet with asbestos fiber also makes a Parts by weight stronger ash than sheet with other fibers. W a te r_________________________________________ 89 The first type sheet is somewhat weak so that it can be Alumina trihydrate_____________________________ 10 broken up in regular tobacco cutters and handling appa A sb estos_______________________________________ 1 ratus to a satisfactory length for a good ash. It, therefore, 65 Guar g u m _____________________________________ 0.5 can be fed in 2-3" strips directly to the tobacco leaves G ly cero l________________________________________ 0.25 any place before the cutters. 31% formaldehyde preservative, 6 cc. per gallon o f slurry. The second type sheet reduces the temperature without tar reduction (no internal filtration). This sheet is pro A ll dry components, alumina, asbestos and guar gum, duced from the same raw materials and in a similar man 70 vere dry ground in a hammer mill prior to mixing with ner to the first type sheet but generally using more con hot water to improve the casting and sheet forming char centrated and viscous slurry and removing the sheet acteristics o f the slurry. The slurry was made into a sheet without scraping from the drying surface. The sheet there by feeding evenly onto a polished steel conveyor belt with fore is smooth on both surfaces and exposes very little a steam chest on the underside for drying; or by passage asbestos fiber. 75 through a hot air furnace for drying. 3 ,410,276 7 8 Example 4 in the neutral fraction which showed a 26% decrease in These are examples of common fillers that may be used the smoke from the alumina sheet cigarettes. with the asbestos matrix. The change in chemical character of the smoke may (1 ) A stock matrix slurry was prepared by blending be partly attributed to the fact that the alumina dehy- two minutes in an Osier blender (a ) 6 grams chrysotile 5 drates to a highly porous and activated form (gamma asbestos, (b) 3 grams Burtonite No. 78 Guar gum, (c) and eta phases) during the heating, thus providing a 1.8 grams glycerol, (d) 1000 milliliters distilled water. possible catalytic action on the chemical reactions tak (2 ) To 250 milliliters of above matrix slurry were ing place during pyrolysis, and partly to chilling, con added respectively:'(a) talc, 15 grams (b ) kaolin clay, densing, adsorption and internal filtration effects that pro- 15 grams, and (c) ferric hydroxide, 15 grams (d ) silicic j 0 foundly alter conditions in the critical distillation zones acid in the amount of 15 grams. Each slurry was then o f the cigarette, and also permit the more rapidly con blended in the Oster blender. The four slurries were densed fractions to be re-exposed more times to the peak then cast on Teflon sheets and dried at 105 C. in an elec burning temperature. tric oven until dry. The sheets were removed after drying Thus the presence of increased moisture and cooler iand examined; the sheets were typical, pliable and ac 15 average temperature during pyrolysis, coupled with the ceptable. possible adsorptive and catalytic action of the activated The novel tobacco additive temperature control sheet alumina is conducive to the formation of different pyro of the invention produces many unexpected and advanta lytic products. Such changes are evident in Table 2. D es geous effects. In the following discussion, cigarettes made pite these changes there is still a satisfying taste. with a tobacco filler containing 23% by weight of the 20 Another important advantage of the alumina sheet preferred alumina trihydrate-asbestos-guar gum sheet of lies in the fact that the rough-surface shredded sheet in the invention will serve for purposes of illustration. admixture with the tobacco acts as an internal filter in The most important advantage obtained in incorporat the cigarette. Thus it provides not only thermal control ing the shredded sheet in the tobacco lies in a reduction and improvement of chemical composition of the smoke of between 100 and 200 C. in the average prevailing 25 from the standpoint of carcinogens, but by acting as a temperature in the critical distillation zone o f cigarettes filter, the rough-surface shredded sheet provides a meas containing the sheet as compared with those which do ure of control of tar passing through. A s explained pre not. This reduction effect is observed both in filter and viously, the internal filtration is obtained by a rough sur nonfilter types of cigarettes. The following table shows face on the sheet which may be produced as such, or the these average smoking temperatures for various types of 30 surface may be made rough by hammer milling or break cigarettes made in factory machines and the temperature ing in a double cone mixer with intensifier bar. The differences obtained with and without the sheet additive. rougher the sheet surface the more effective is the filter The sheet additive has little apparent effect on the peak ing action. The presence o f fines in addition to the twisted burning temperatures, which were about 850 C. for all shreds, to get into the interstices and exert a blocking the cigarettes. 3 action on the flow, increases internal filtration. This is Type of Cigarette TABLE t Average Active Zone Temperature, C. Temperature Difference, C. accomplished, for example by longer conditioning of the sheet as formed by treatment in the hammer m ill or double cone mixer with intensifier bar. 40 These internal filtration effects are illustrated in the following table, which shows test results per cigarette Control, no filter.......... _.............. 595 Sheet, no filter.............................. 480 Control filte r............................... fii Sheet filter................................... 425 115 made in factory machines in terms of changes in tar, nicotine, ash, and air flow rates, with and without the 200 additive. TA BLE 3 --T A R AND N IC O T IN E C O N TEN T OE SMOKE Type of Cigarette Wt. in gms. Wt. of ash, mgs. No. puffs Tar, mg. Nicotine, mgs. Air flow rate, ce./sec. Control, no filter............ 1.18 119 10.1 25.8 Sheet, no filter............. 1.26 266 11.9 13.1 Control filter................... 1.07 99 8.9 18.8 Sheet filter...................... 1.11 211 10.2 10.9 2.4 22.5 1.1 12.6 1.5 12.7 0.8 10.1 This temperature reduction effect is attributable to 55 In the foregoing table, the measurements o f number the high heat demand of the alumina trihydrate, which o f puffs, tar and nicotine were made at a standard smok is about 900 B.t.u. per pound. Liberation o f the water ing rate of 35 cc./2 sec., once a minute, to a butt of 26 o f hydration occurs at 250-600 C., within the critical pyrolytic range. mm. for filter cigarettes, and of 24 mm. for plain ends. Air flow was measured in cc./sec. under 2s/& inch water Another favorable effect arising from the use of the 60 draw. sheet additive of the invention lies in an improvement The internal filtration effect of the shredded sheet is in the chemical composition o f the smoke. The following indicated by the average reduction of about 45% in tar table indicates that the chemical composition of the smoke and 50% in nicotine as compared with cigarettes using has been appreciably altered, particularly in the impor plain tobacco. tant basic and neutral fractions. TABLE 2 --ANALYSIS OF FR A C TIO N S IN SMOKE [Percent of Fraction in Tar] Type of Cigarette Insoluble Basic Strong Weak Neutral Acid Acid Control, no filter............ 5.1 Sheet, no filter................ 5.7 Control filter.-................ 5.8 Sheet filter...................... 8.3 39.4 9.6 14.0 31.9 48.4 8.2 13.9 23.8 36.0 8.6 18.0 31.7 49.5 7.2 12.4 22.7 65 In terms of comparative mildness, the mildest was the cigarette employing both sheet and filter, while the next mildest was the cigarette employing sheet and no filter. The standard filter and non-filter cigarettes were respec tively, next harshest. Thus the additive o f the invention 70 can be employed in an amount sufficient to produce the necessary thermal control, while producing a mild satis fying flavor and a reduction in tar and nicotine as great as that of an ordinary filter. Of course, a conventional With reference to Table 2, the polycyclic hydrocar filter could also be employed to further decrease tar and bons, which would include the carcinogens, are mainly 75 nicotine to new low levels, but it alone cannot provide the complex internal filtration effect of the present in per minute, while the cigarette containing 0.75 gram vention. tobacco burned at the rate of 6.55 mm. per minute. In Another advantage in the use of the additive of the in contrast thereto, the cigarette containing 0.75 gram of vention lies in the fact that the combined water in the tobacco and 0.25 gram of temperature control substance alumina, about 10% of dry tobacco weight, cannot be of the invention burned at the rate of only 3.55 mm. per. lost in storage. It is present to increase the moisture in 5 minute. the smoke, thereby reducing the effect of any loss of A s indicated previously, there can be employed, in ac free moisture of the tobacco prior to use. Normally cordance with the invention, a non-filtering type of there is a drying out o f the tobacco in the cigarettes on shredded sheet, which gives the same temperature reduc prolonged storage, regardless of type of packaging. This tion and mildness of smoke as the internal filtering sheet, greatly increases the tar and nicotine developed in the 10 but no substantial reduction in tar and nicotine content of smoke. The shredded sheet provides excess water in a the smoke. Nevertheless, the non-filtering sheet effects an combined storage-stable form which is available for equal reduction in distillation zone temperatures, provides thermal control and humidification when the dried out a mellowed smoke and prolongs smoking time. It is also cigarette is burned. The water of hydration helps com possible, in accordance with the invention, to convert the pensate, during smoking, for any moisture previously 15 non-filtering type of sheet to the internal filtering type of lost from the tobacco. The additive permits a net re sheet, if desired, as explained previously, so that there is duction of the amount o f tobacco present, but without present the advantage of having to produce initially only detriment to smoking satisfaction. one type of base sheet. In both cases, however, asbestos As indicated previously, the alumina present in the is the material o f choice, since it provides a stronger tobacco additive of the invention acts to reduce by some 20 sheet and ash. 35% to 40% the polonium contaminants in the main The following example shows the preparation o f the stream smoke. This is demonstrated by comparative tests nonfiltering type of sheet, using asbestos. conducted on cigarettes with and without the alumina additive, the latter serving as controls, the cigarettes being both with and without filters. Tobacco and smoke 25 Example 5.-- Non-filtering type sheet 2.75 lbs. of grade 3K700 chrysotile asbestos and 2.75 samples were analyzed for polonium-210, smoking two lbs. grade 4A700 chrysotile asbestos were placed in a 3 samples of each of the mentioned types of cigarettes. The cu. ft. Patterson-Kelley twin shell blender rand blended results are set forth in the following table. for 15 minutes with intensifier bar at 2510 r.p.m. and shell TABLE 4.--POLONIUM-210 IN C IG A R ET TE SMOKE [Unit: Picocuries per cigarette] Type of Cigarette Main- Side B utt Ash Tobacco stream Stream Control, no filter___ ____ Sheet, no filter................... Control filter...................... Sheet filter......................... 0.130 0.076 0.067 0.043 0.140 0.10 0.051 0.40 0.110 0.14 0.043 0.37 0.130 0.096 0.041 0.38 0.089 0.072 0.045 0.28 speed 25 r.p.m. There were then added to the blender 30 contents 3 lbs. Burtonite N o. 78 guar gum and 50 lbs. of alumina hydrate of minus 325 mesh particle size, and the entire mixture blended for 5 minutes. The dry discharge from the blender was fed to a high speed, multi-hammer, 35 hammer mill, equipped with a Vi inch screen. Nine batches of the discharged dry mix was slurried in 4100 lbs. water at 180 F. containing 15 lbs. glycerine. The slurry was The results indicate that the Po210 content of mainstream vigorously agitated 30-60 minutes. If desired, the dry mix (inhaled) smoke from cigarettes with alumina sheet was may be slurried in water at ambient temperature and al about 40% less than that from control cigarettes. 40 lowed to remain at ambient temperature. Mixing time In order to determine the burning characteristics of the varied, up to 5 hours, according to which temperature is tobacco mixtures with the additive sheet shreds of the used. The slurry properties were: viscosity about 4,000 invention, tests were carried out on a conventional smok cps. (Brookfield No. 4 spindle at 12 r.p.m.) at 160' F. or ing machine of a type designed to simulate cigarette about 6,500 cps. at 100 F., density 1.0-1.2 grams percc., puffs at spaced time intervals. 45 solids content 10.8%. Several series of the cigarettes each were prepared, The slurry was spread on a continuous stainless steel and tested in the smoking machine employing a thin conveyor belt 48 inches wide by a suitable feeder doctor thermocouple drawn through the center of the cigarette blade arrangement to give a film of the slurry 37-40 mils at a distance of 30 mm. from the burning end of the thick and 44-45 inches wide. The belt was then heated on cigarette. The machinery was adjusted for standard smok 50 the underside with steam until the slurry was evaporated ing conditions to take one 35 cc. puff per minute for a to dryness. Drying required about 2.5-3.0 minutes at 230 period of two seconds duration for each puff. F. and gave a dry product 5 -8 mils thick. As the dry prod The tested series were as follows: uct came out of the drying oven, a cool shower o f water was sprayed on the underside of the drying surface, the A . Per cigarette: 0.75 gram tobacco; no additive; B. Per cigarette: 1.0 gram tobacco; no additive; 55 water being at 60-75 F. The cooled product and belt were then subjected to a very small amount of live steam C. Per cigarette: 0.75 gram tobacco plus 0.25 gram of (1 0 -2 0 lbs. steam per 350 lbs. dry product) which im alumina hydrate-asbestos sheet. pinged on the surface. This steam penetrated the product The accompanying drawing shows a set of curves com and condensed on the cold metal surface below to form paring temperature in degrees centigrade with the dis 60 a very thin film of water between the drying surface and tance the cigarette has burned from the original lit end the product. Although the condensed steam was rapidly to the point at which the thermocouple was inserted, 30 absorbed by the product, the product was loosened from mm. from the original end. The curves indicate that, for the drying surface and could be lifted therefrom without a given distance burned, the temperature at the point scraping using a doctor blade for lifting. The stripped where the thermocouple is placed, averages considera 65 sheet was then redried to remove residual moisture from bly lower for the cigarette made with alumina-hydrate- the steaming operation. asbestos sheet material of the invention. The ash, more The dried sheet was further processed by placing 25 lbs. over, remains firm. Thus, the cigarette of the invention in a Patterson-Kelley blender for 1.5 minutes to produce provides a good ash, a much lower temperature in the shreds o f the sheet approximately 0.5-0.75 inch in diam distillation and destructive distillation zone, and a greatly 70 eter. This shredded product was then screened on a Tyler lengthened time of burning or smoking, as compared 18 mesh screen to remove any fines and the plus 18 mesh with an untreated cigarette. This greatly lengthened burn material was ready for incorporation with tobacco. This ing rate may be seen from the curves of the accompany shredded sheet was of the non-filtering type, reducing aver ing drawing. Thus, the cigarette containing 1 gram of' age active temperatures, but giving no significant reduc tobacco with no additive burned at the rate of 4.37 mm. 75 tion in tar or nicotine. 3,410,276 11 12 Example 6.-- Conversion of non-filtering to filtering sheet 75% to about 95% by weight of an aluminous tempera ture control substance united with water; and in addition (b ) from about 3% to about 15% by weight o f a siliceous Two parts by weight of the dried product from Exam inorganic fibrous matrix material; and in addition (c ) ple 5, was admixed with 1 part by weight o f product S from about 1% to about 5% by weight o f an organic prepared similarly, but processed in the Patterson-Kelley gum binder selected from the group consisting of natural blender for 5 minutes, instead of 1.5 minutes. The mix vegetable gums and synthetic cellulose ether gums; the ture of 25 lbs. o f 5-minute treated material and 50 lbs. of fibers of said matrix material having been treated to pro 1.5 minute treated material was thoroughly blended and duce a roughened fibrilated surface thereon. then screened on a Tyler 18 mesh screen to remove fines 4. The tobacco of claim 3 in which the fibrous matrix produced during the shredding process. The plus 18 mesh material is asbestos. mixture when incorporated into tobacco will not only 5. The tobacco of claim 3 in which the binder is guar reduce temperatures, but will produce a significant reduc gum. tion in tar and nicotine. 6. Smoking tobacco having incorporated therein from The internal filtering type o f sheet exerts an effect in jg about 10% to about 25% by weight of the tobacco o f tar reduction far greater than that attributable to the fibrous shreds consisting essentially of (a) from about reduction of the tobacco content o f the cigarette alone. Table 5 and the curves o f the accompanying drawing were developed by determining the mg. o f dry tar per cigarette 80% to about 90% by weight of alumina trihydrate; and in addition (b ) from about 5% to about 15% by weight of asbestos; the balance being at least 1% by weight o f a in comparison to the percentage o f sheet additive. The 20 natural vegetable gum binder; said fibrous shreds having theoretical tar reduction curve was calculated by multi been treated to produce a roughened fibrilated surface plying the dry tar from the control cigarette by the per thereon. cent o f tobacco that would be left after the designated per 7. The tobacco o f claim 6 in which the gum binder is cent addition of sheet. A ll cigarettes tested had the same guar gum. initial weight, and were hand-made on a laboratory ma 25 8. A cigarette comprising a filler o f smoking tobacco chine. having incorporated therein from about 5% to about 35% It will be seen from Table 5 that for a level o f 16% by weight of the tobacco o f a shredded sheet consisting sheet additive, the theoretical control cigarette would give 13.9 mg. of tar. But only 9.7 mg. o f tar was evolved from essentially o f (a) from about 75% to about 95% by weight o f a temperature control substance selected from the TABLE 5 Kind of Cigarette Percent Sheet Additive Tobacco Content Factor Dry Tar, mg./cigarette Control........................................................ T ar calculated from percent shoot loadings. Non-Filtering Sheet. Internal Filtering Sheet. 0 1.00 16.5 8 .92 15.2 16 .84 13.9 24 .76 12.6 32 .68 11.2 8 13.9 16 .................... 12.1 24 .................... 11.6 32 11.2 8 ..................... 16 24 32 12.2 9.7 7.8 7.0 a cigarette with 16% of the internal filtering type sheet group consisting of an oxide, hydroxide, and carbonate of additive, representing a reduction from the theoretical of magnesium, and an oxide and hydroxide of aluminum, 4.2 mg. tar, or about 30%. A t 24% or 32% sheet load and the hydrated forms thereof; and in addition (b) from ings, the reduction was about 4.5 mg. tar, or 36% and about 3% to about 15% by weight o f a siliceous inor 40% reduction, respectively, below the theoretical evolu ganic fibrous matrix material; and in addition (c ) from tion. The non-filtering type o f sheet gave little or no re 50 from 1% to about 5% by weight o f an organic gum binder duction of tar below the theoretical value. The foregoing selected from the group consisting of natural vegetable figures are for dry tar (105 C .), thus having greater gums and synthetic cellulose ether gums; the fibers of significance as being undiluted with volatile smoke frac said matrix material having been treated to produce a tions which do not contain carcinogens. What is claimed is; roughened fibrilated surface thereon, and a cigarette paper 55 wrapper. 1. Smoking tobacco having incorporated therein from 9. A cigarette comprising a filler o f smoking tobacco about 5% to about 35% by weight o f the tobacco of a having incorporated therein from about 10% to about shredded sheet consisting essentially of (a ) from about 25% by weight of the tobacco o f fibrous shreds consist 75% to about 95% by weight of a temperature control ing essentially o f (a) from about 80% to about 90% by substance selected from the group consisting of an oxide, 60 weight of alumina trihydrate; and in addition (b ) from hydroxide, and carbonate o f magnesium, and an oxide about 5% to about 15% by weight of asbestos; the bal and hydroxide of aluminum, and the hydrated forms ance being at least 1% by weight of a natural vegetable thereof; and in addition (b ) from about 3% to about 15% gum binder; said fibrous shreds having been treated to by weight of a siliceous inorganic fibrous matrix material; produce a roughened fibrilated surface thereon, and a and in addition (c ) from about 1% to about 5% by 65 cigarette paper wrapper. weight of an organic gum binder selected from the group consisting of natural vegetable gums and synthetic cellu References Cited lose ether gums; the fibers of said matrix material having been treated to produce a roughened fibrilated surface UNITED STATES PATENTS thereon. 70 2. The tobacco of claim 1 in which the fibrous matrix material is asbestos. 3. Smoking tobacco having incorporated therein from about 5% to about 35% by weight o f the tobacco o f a 3,005,732 3,061,479 3,106*210 3,255,760 10/1961 S p e c h t_______________ 131-- 17 10/1962 M erritt________________ 131-- 17 10/1963 Reynolds et al__________131-- 17 6 /1 9 6 6 S e lk e _________________ 131-- 17 shredded sheet consisting essentially o f (a ) from about 75 MELVIN D . REIN, Primary Examiner.