US2933420A - Tobacco composition and smoking unit containing material for eliminating deleterious matter - Google Patents

Description

United States Patent TOBACCO COMPOSITION AND SMOKING UNIT CONTAINING MATERIAL FOR ELllVIINATING DELETERIOUS MATTER Application December 26, 1957 Serial No. 705,088

11 Claims. (Cl. 131-17) No Drawing.

This invention relates to smoking compositions and to smokable units including therein a novel particulate inorganic material intimately associated with tobacco, the additive being capable of substantially reducing the quantity of tars normally generated during the burning of the tobacco and improving the aroma of tobacco. For many reasons, clinical and aesthetic, reduction in the tar yielded during the smoking of tobacco is highly desirable. First, there exists strong clinical, statistical and pathological evidence that certain constituents of tobacco smoke condensate (or tars as such condensate is usual- 1y termed) are potentially carcinogenic when deposited on human tissue. These carcinogens have been reported to be mixtures of essentially neutral high-molecular weight polycyclic hydrocarbons, the carcinogenic potency of any mixture depending on the species present. Several general types of polycyclic aromatic hydrocarbons are usually present in. tobacco smoke condensate and undoubtedly many individual molecular species are hence present. Deleterious polycyclic hydrocarbons are undoubtedly of pyrogenic origin since they cannot be isolated from raw tobacco prior to the pyrolysis thereof. These noxious substances are ordinarily carried as dispersed droplets or solid particles in the eflluent smoke stream and thence into the smokers respiratory system along with the aroma and taste producing constituents of the smoke. Secondly, aside from their alleged pathological efifect, it appears that certain constituents of tars are responsible for the sharp irritating taste imparted to smoke from a cigarette or the like. Furthermore, tars produce disfiguring coloration of the teeth of many smokers and, if only for this reason, the lowering of total tars 'yielded during smoking is highly desirable.

Many efforts have been made in the past to reduce the yield of tars in the efiiuent smoke of tobacco. The use of filter-tips, for example, has met widespread acceptance both by the cigarette industry and the consumer. Another method involves the commingling with smoking tobacco of particulate porous solids having high sorptivity by virtue of their large specific surface, internal or external. The inclusion of a variety of sorptive clays, colloidal and non-colloidal, in smoking mixture has been suggested in the prior art. Reduction of tobacco oils,

ering the tar yield of said tobacco when smoked meets a long-felt need of the tobacco smoker.

Accordingly, it is a principal object of the instant invention to provide a composition including tobacco which incorporates a novel treatment mineral which functions during the pyrolysis of the tobacco to reduce substantially the quantity of tars in the smoke efliuent from said tobacco.

Another object of the invention is the provision of a composition including tobacco intimately associated with an innoxious mineral suitably treated prior to association with said tobacco to be rendered capable at the elevated temperatures encountered in smoking tobacco of substantially lowering the yield of tars in the main stream smoke of tobacco. A

It is another important object to provide smoking units including tobacco and a novel particulate mineral additive dispersed through said tobacco and capable of curtailing the quantity of tar generated during pyrolysis of said tobacco.

Other objects will be apparent from a reading of a description of the invention which follows.

in general it may be said that those workers who in the past have proposed inclusion of sorptive solids in tobacco mixtures failed to recognize treatment of the clay mineral prior to inclusion in a smoking mixture would confer unexpected benefits with respect to total tar re duction. For example, Kauffman, in U.S. Patent 2,108,860 teaches the use of non-colloidal bentonite in tobacco mixture, said non-colloidal bentonite. being provided by naturally-occurring non-colloidal bentonitic clays or by heat treating a bentonitic clay which is colloidal in its naturally-occurring state to destroy the colloidal properties. The use of non-colloidal clays in tobacco compositions rather than prior art colloidal clays was suggested by Kauifman for the reason that non-colloidal clays would resistloss of physical form in the presence of moisture. Said Kauffman, in an application of Serial No. 718,246, filed March 30, 1934, and copending with U.S. Patent 2,108,860 teaches the inclusion of oil-decolorizing clay, eg. fullers earth, in tobacco compositions. Other patents have equated the performance characteristics in cigarette compositions of bentonitic clays with so-called fullers earth and have also not distinguished between these materials and their unheat-treated. or colloidal counterparts in tobacco compositions.

the teachings of the prior art in that it is. based on my surprising discovery that a particular mineral substance previously thermally treated within a defined temperature range'to a predetermined maximum reduction of water of composition or combined water provides a novel improved tobacco additive. The tobacco additive oiimy invention represents an advance over proposed prior art additives in that it is one which when intimately associated with tobacco is capable of lowering the quantity of tar yielded by the tobacco to a degree unequaled by the same mineral not subjected to the activation treatment of-the character to be described or, to my knowledge, by other minerals.

The discovery is surprising and unexpected in view of the fact that the mineral, previously heat-treated to bring out its oil-decolorizing properties, has been suggested in the prior art for inclusion in tobacco compositions. The mineral in compositions of my invention, .on the other hand, is heat-treated at a temperature level lower than that used to confer optimum oil-decolorizing properties on the mineral. I have found that when the mineral it heat-treated within the temperature range to make it an oil-decolorant, the outstanding ability of the mineral thus cent or less.

, Total volatilematter, pertreated to reduce tars in smoking tobacco mixtures is not developed. This is contrary to the teachings of the prior art. Likewise the mineral in its colloidal state does not possess to the same degree the outstanding ability to reduce tars generated from tobacco mixtures.

Briefly, I have found that the mineral attapulgite suitably activated to destroy colloidal or gel-forming characteristics without eliminating a substantial amount of combined water provides a unique tobacco additive. Said activated attapulgite, when intimately associated with to- 11 bacco, is able to lower the weight of tars generated from a unit weight of said tobacco to a degree unequaled by said attapulgite not so pre-heat-treated.

A suitable activated attapulgite for purposes of my or water of composition is that remaining after the mineral has been heated at 220 F. to constant weight. Combined water in fullers earth stock is ordinarily about percent based on the moisture-free weight of the mineral.

The activated mineral will preferably include all of the combined water originally held by the mineral although elimination of up to 50 percent of said combined water will not render the mineral unsatisfactory for use in compositions of my invention.

Preferably the mineral will retain at least 80 percent, and within the range of f from 80 to 100 percent of the combined water. The total 'volatilematter content of the preferred thermally activated non-colloidal attapulgite as produced is preferably not less than about 7% by weight, and is usually from about i 9 to. 14 percent, volatile matter (V.M.) being the weight percent ofthe mineral eliminated by heating the mineral "to essentially constant weight at about 1700 F. To

accomplish the requisite elimination of free water and destruction of the gel-forming properties of the attapulgite and thereby confer upon the attapulgite the necessary properties for use as a cigarette additive I employ a mineral previously activated at a temperature of the order of about 400 F. In general, calcination periods of the I order of about A to /2 hour will suffice to achieve the requisite activation of the mineral at 400 F. although somewhat lower periods of time may suffice with some stock and longer calcination times may be indicated for other stock. The temperature level of the treatment is lower than that at which optimum oil-decolorizing efficiency is imparted to the mineral. Calcination of the 'mineral at temperatures of from 600-900 F., and particularly 700900 F., for 15 to minutes to remove a major portion of combined moisture is ordinarily practiced in making an oil-decolorant from attapulgite. Such an oil-decolorizing material has a of about 6 percontaining as a chief mineral constituent attapulgite.

Typical chemical analyses of some suitable attapulgite- :co'ntaining clays is as follows:

Chemical analyses of attapulgite contair zing clays cent Free moisture, percent Volatile-free basis, percent:

' Others..-

Attapulgite is anhydrous of lathlike structure and is distinct in morphology and properties from the various montmorillonite minerals which are the chief mineral constituents of bentonitic clays. Commercial Attapulgus clays frequently contain, in addition to a major portion of the mineral attapulgite, other mineral constituents suchas minor proportions of montmorillonite minerals, sepiolite, quartz and feldspar. The distinctive differential thermal analysis curve-of the mineral is shown in Clay Minerology, R. E. Grim, page 199 (1953). Therein it is shown that attapulgite is identified by an initial endothermic reaction below about 400 F. and additional endothermic reactions at about 450 F. to 650 F. and (750-1000 F.) corresponding approximately to the intervals of abrupt water losses shown by the dehydration curves. The small loss in water above about (1000 F.) does not produce a thermal reaction adequate for recording. The nature of the water lost during these dehydrations varies, and as would be expected, the properties of materials subjected to treatment at different thermal levels vary-inter se. a

Attapulgite, activated as heretofore described, and commingled with tobacco in amount of from about 1 to 20 percent, and preferably 2 to 15 percent, based on the weight of the tobacco, is capable of effecting substantial quantitative curtailment of smoke condensate. The amount of reduction bears a relationship to ratio of attapulgite to tobacco in a composition, maximum effect being observed in the upper range of additive to tobacco ratios. The specific reduction in tar over that produced by tobacco in the absence of additive will depend, inter alia, on the tobacco specie or tobacco species present, quantity and nature of humectant and other tobacco treating agents. The optimum ratio of total additive to tobacco to effect the maximum tar reduction consistent with satisfactory ease of draw, ability of the mixture to sustain burning, preservation of redolence and the like, is best determined experimentally for a specific tobacco composition. It may be generalized, however, that when attapulgite is present in an amount beyond the maximum expressed in the preferred range that the ability of the mixture to sustain burning may be reduced to some degree and that the tar reduction may be excessive to meet the requirements of many smokers who desire a relatively full-bodied smoke.

The mineral is preferably incorporated in the tobacco in a very-finely divided form, usually less than about 10 microns and preferably having a substantial portion between about 0.5 and 5 microns. In general the more fully-divided the mineral the greater the adhesion to the tobacco. Of course it will be understood that the particularparticle size used in a tobacco composition will depend on such factors as moisture content, quantity of humectant, size of tobacco particle and quantity of mineral additive used.

The additives may be dispersed substantially uniformly throughout the body of the cigarette or, pursuant to an embodiment of the invention, it may be placed selectively within the cigarette to effect maximum benefits. Accordingly, the mineral advantageously may be gradated throughout the cigarette with maximum content proximate the inhaling end where, during the smoking of the cigarette, maximum tar deposition is encountered.

A filter, either of the well-known type which is integral with the cigarette or of the holder type including a filter, is optionally employed in a smoking unit comprising tobacco mixtures of' my invention. The filter may be fibrous and/or include adsorbents such as silica, clays or the like. The purpose of the filter is to prevent inspiration of any finely-divided catalyst and/or dehydrated lime particles which may occur if the cigarette is subjected to dry, warm weather for prolonged periods. The filter interposes a bed of porous material, or the like, between the tobacco-catalyst mixture and the smokers th a d mp o ny p r icle which might otherwise magnesium aluminum silicate tirawn-into the smokers'rn'outh. However, lay proper selection of moisture content and, in some cases inclusion of humectant in the composition, the filter may be bibs-3 12 the attapulgite (expressed in terms of estatesnstant) is as. follows (volati1e-free basis):

Cigarette-attapulgite samples including percent attapulgite (based on the weight -of the tobacco) and in one case percent attapulgite were prepared by dusting the dry additive onto the tobacco shreds prior to packing the mixture into cigarette paper. The composition of Percent ormfledsio 67.0 When the adhesion of a particulate additive to the 5 1 0 5 tobacco is inadequate a binder, such as sodium silicate or p o 40 a pectic substance, suitably pectin derived from tobacco o 1 leaf, may be used to improve adhesion between the to- 0 25 bacco and that additive. Others 3.0 Although the description of the invention has been 10 made with particular reference to cigarettes, it will be 60 understood that the compositions herein provided are applicable to other smoking units. The outstanding benefits realized when attapulgite, The following example is given only for the sake of suitably activated, is cornmingled with cigarette tobacco further illustrating my invention and is not to be conis illustrated in Table I wherein all results of tar yields strued as limiting the scope thereof. were obtained by the aforedescribed in vitro smoking In the example of my invention which follows, all method.

Table I Appr. Tar yield, Temp. oi V.M. (As Percent milligram Cigarette Additive Additive Produced), Combined per0.90gram Treatment Percent Water tobacco Retained 1 None 35.3(av.of6). 2 5% Attapulgite (colloidal)- 250-300F 100 3 13 3---. 5%Attapulgite 700F./%hr-- 4.4 44 1% a 4---..-- .do... 400F./%hr 11 90 3 13 10% Attapulgite 400F./ /ihr-- 11 9o 26M cigarettes were mechanically smoked by the method de- I claim: scribed in detail in Industrial and Engineering Chemis- 1. A smoking mixture comprising a major portion of try, vol. 28, No. 7, in an article entitled Nature of Cigtobacco and intimately associated with at least a portion arette Smoke-Technic of Experimental Smoking, 1. A. of said tobacco finely-divided non-gelling activated atta- Bradford et al., pp. 836-839, inclusive (1936). Analypulgite, said attapulgite having a major portion of comsis of total tar content was made by collecting the bined Water retained therein. tobacco smoke in a glass wool filter tube at room tem- 2. A smoking mixture comprising a major portion perature and evacuating the tube at room temperature of particulated tobacco and dispersed therethrough and to eliminate moisture. Quantitative determination of tar intimately associated therewith finely-divided non-gelling yield was measured by calculation of the weight pick-up activated attapulgite having a major portion of combined of the tube after removal of moisture therefrom. The water retained therein. mechanical smoking method employed approximates the 3. A smoking mixture comprising a major portion of conditions of human smoking sufficiently for conclusions tobacco and intimately associated with at least a portion of in vitro experiments to be interpreted in vivo. of said tobacco finely-divided non-gelling activated atta- The efiect of the activation of attapulgite prior to pulgite, s id attapulgite having 80 to 100 percent of cornits inclusion in a tobacco mixture on its ability to benebined water retained th r in. ficially alter the smoking characteristics of said tobacco 4. A smoking mixture comprising a major portion of was explored. The ability of diiferent fractions of minparticulated tobacco and dispersed therethrough and inoral, variously thermally treated, to reduce the tar yield timately associated therewith from about 1 to 20 percent per unit is shown in the example. Samples of cigarettes by weight of said tobacco of finely-divided non-gelling re p pa d each comprising gram of a p pu activated attapulgite, said attapulgite having from about brand shredded tobacco blend packed in conventional 80 to 100 er t of ombined water retained therein. cigarette paper. The moisture content of the tobacco 5. A smoking mixture comprising amaior portion of blend was approximately 12 percent. Control cigarettes particulated tobacco and dispersed therethrough and intiincluding no mineral additive Were prepared. h r gmately associated therewith from about 2 to 15 percent arettes were prepared each including in addition to 0.90 by weight of aid tobacco of finely-divided non-gelling gram of tobacco finely-divided atiaplllgite- Included in activated attapulgite, said attapulgite having from about the survey were three samples of attapulgite which had 80 to 100 percent of combined water retained therein. been heat-treated at different temperature levels: col- 6. The smoking mixture of claim 5 in which said attalOidal p g dried at beiwfien attapulgite consists essentially of particles of less than about pulgite heated at about 400 F. for /2 hour to a V.M. 10 microns. (as produced) of about 11 percent; and an attapulgite 7. A smoking unit comprising a major portion of useful as an oil. decolorant which had been heat treated tobacco and intimately associated with at least a portion at 700 F. to a V.M. (as produced) of about 4.4 percent. of said tobacco and intimately associated therewith from about 1 to 20 percent, based on the weight of said tobacco, of finely-divided non-gelling activated attapulgite, said attapulgite having a major portion of combined water retained therein.

8. A cigarette comprising a column of particulated to- "bacon .and dispersed throughout said tobacco and intini atel'yass'ociated therewith from about 1 to 20 percent, basedon the weight of said tobacco, of finely-divided nongelling activated attapulgite, said attapulgite having a major portion of combined water'retained' therein.

19. A cigarette comprising a column of particulated ."tobacco and dispersedthroughout said tobacco and intimately associated therewith from about 2 to 15 percent,

based on the weight of said tobacco, of finely-divided non- "gelling activated attapulgite, said attapulgite having from about 80 to 100 percent of combined water retained "therein.

.- 10. The cigarette of claim 9 in which a free end of i said column terminates in a filter-tip. 11. A cigarette comprising a column of particulated 15 tobacco, said column terminating at a free end thereof in a filter-tip, and distributed through at least that portion of said column contiguous to said filter-tip and intimately associated withY th etobacco therein, finely-divided nongelling activated attapulgite, said attapulgite having a 5 major portion of combined water retained thereim References Cited in file of this patent I UNITED STATES PATENTS Great Britain Feb..

Claims (1)

1. A SMOKING MIXTURE COMPRISING A MAJOR PORTION OF TOBACCO AND INTIMATELY ASSOCIATEDS WITH AT LEAST A PORTION OF SAID TOBACCO FINELY-DIVIDED NON-GELLING ACTIVATED ATTAPULGITE, SAID ATTAPULGITE HAVING A MAJOR PORTION OF COMBINED WATER RETAINED THEREIN.