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FILE NAME Kent KNT DATE 1956 Sept 4 DOC KNT026 DOCUMENT DESCRIPTION Patent - Filter for Tobacco Smoke United States Patent Office Office Patented 2,761,798 1956 material in which some of diahm ave e dia- me- -ters -ters outside in 0.1 0.6 micron range saty he substantial 2,761,798 range of microns provided a pro- FILTERTOBACCOTOBACCO SMOKE the portion of 5 specified diameter are present . the case of asbestos it has been found that fibers Harold . Knudson Norwood Mass assignor to & Y ? of the specified small diameter exist onliyn the form of Walpole Mass Specialties Co. Inc. East Hon Massachusetts a corpora- very short lengths them of the 0.004 Massachusetts and P. Lorillard Company New 0.012 inch few in length although may NY corporation of New Jersey jointly as much us inch in length Asbestos which has been incon- April 24 1956 Application Serial 580,241 10 -pletely opened may contain sticks or bundles which 2 Claims Cl 131 10 . This invention concerns filter means for treating or conditioning tobacco smotokthee end of rendering it less irritating or toxic Although there has been much debate on the subject it seems generally agreed that tobacco smoke particularly - when inhaled is at potentially harmful especially in the instance of individuals suffering from vascular and similar disorders In the treatment of such cases it has hasbeen found that substantial reduction or complete cessation of smoking frequently produces even more harm- of shock both ful effects because cal totheindividual's system physical and psychologi- A dilemma is thus presented the resolution of which in an individual is never true solution The problem one which is of in- diameter exist longer appear fibrous and which are considerably longer than 4 inch these will have diameters greater than microns While other fibers particularly synthetic fibers havingthe specified small may 15 lengths substantially all the small diameter to micron in the filter the present invention have length less than i...nch The carrier fiberbse conventional textile fibers 20 cotton rayon other cellulosic fibers being preferred although wool nylon fibers as well as fibers other synthetic materials may also be employed These fibers normally have diameters the order of cotton fibers e 25 microns The length of the carrier fibers vary 25 upwardly from the inch even although preferably at least 4 inch long may be much -as - several inches long although normally of course their length will greater the over : dimensions of the filter ; creasing magnitude due to the increasing popularity of have found that most smokers do not consider the -cigarette smoking 30 flavoorf the tobacco objectionally impaired when from Even apparently physically sound individuals may show minor blood pressure changes due smoking as to -60 by weight of the tars andAcordingly nicotianree re- moved from the tobacco smoke Accordingly my these individuals nose and throat irritatioisn ofgreat- est concern My invention enables the removal of desired portion of the tars and nicotine present in tobacco smoke which account for its irritating properties and potential toxicity Actually of course complete these substances is not desirable due to considerationofs taste ventioins represented its preferred embodiment a filter manufactured to specifications which provide for 35 the removaolf from -60 by weight the smoke particles usually -50 Generally and preferably such filter comprises about -20 small diameter fibers 0.1 0.m6icron based on the weight all the fibers in the filter ; diameter fibers and flavor Moreo thev eve enrt of the tars and 40 It will of course be understood that the quantity of nicotinaere removed no smoke is produced ise the the tobacco smoke particles removed is not entirely a smoker draws into his mouth only colorless highly function of the concentration the small diameter fibers signifi- unpalatable combustion gases . It nevertheless since the density of the mixture and the diameter -cant as -cant illustrating the remarkable nature my invention and length of must also considered As to that can in fact achieve almost complete removal the cigarettes I customarily the filter - combining : substanceansd even within the limits imposed by -20 small so that has diam practical factors such as the necessity for maintaining a eter of about 0.81 0.83 centimeter length of about free draw and the relatively length of filter 0 to 1.5- centimeters and an apparent specific - gravity per in .cigar and cigarette holders * weight unit volum grae ms per cubic centimeter My invention previously indicated form 50 ~ of from to 0:23 obviously of screening or disposed in the path of The density of the filter is obviously most important the tobacco . The : filter is distinguished that factor there can substantial interference with it comprises a substantial proportion of asbestos or other draw It is this limitation density or compactness the didaimaemteetrer fibers having small a diameter corresponding to particularly 55 prevented the development of a of the smoke particles removed and really satisfactory tobacco smoke filter heretofore In- . being the order micron these fibers being terestingly conventional paper filters filters | substantially uniformly .. distributed in uncompacted fashion in carrier fibers of substantially greater . diameter the latter being present in predominant proportion While mineral fibers such asbestos glass fibers specified diameters have been found be _terials particularly satisfactory fibers of a variety of other _terials as cellulose acetate viscose rayon andpolyefisberts esurch as Orlon and Dacroarne satis- factory provided their diameters are within the specified range As practical matter it is difficult and expensive to supply of small diameter fibers all any of which can have diameter within the range micron mixed with somewhat diameter the objects of the present invention be attained by employing as the source of small diameter fibers a the type comprising spun viscose are capable at best of removing more th%a-n 30 of the particles mak- -ing up -tobacco before unreasonable interference 60 with draw ; ; of as that customarily In the manufacture of my filter it important the blending of two classes fibers be uniform as possible Using asbestos as the diameter - fibers and cotton fibers as the carrier fibers 65 - effect the blending on conventional - textile machinery Thus I feed together lapper laps one two fibers the other comprising cotton fibers the theasbestos fibers delivers the laps to thecylindeofr a - cotton carding machine the product of which is sub- 70 stantially uniform web of the mixed having pre- sdetermined thickness - Alternatively -a -mixing picker such as is used in the wool industry may be employed inin 2,761,798 4 rtbaohpveepiradwnreognesroniktrtrhmieeassndtlpgberlyaceotypinofpfglitychingorbibnedae3 lrsomaatthnieenryiwtachhlaoessloseefruibcpeharsssed to the of the patthhaeidfiber situation represebneteenndutmhe- the . + the preliminary blending and the blend may be delivered best explained with of diagrams It has de- _ to the hopper of a carding machine In any case termined that the diameter the particles constituting the in the carding machine not only brings about tobacco smoke is about 0.1-0.6 micron Since the di- ._ _ blending but operates to open up the ameter of paper fibers of the type heretofore employed in asbestos fibers as is manifestly necessary A shaped tobacco filters is of the order of 10-25 microns there is is formed from the web and cut into lengths de- presented a situation such as portrayed in Fig , where termined by the length of the particular filter Where A is a smoke particle B is section of the paper encasement the roving is considce onsrideerd ed de- fiber C is a slip line representing the flow of the air . "| sirable the roving may drawn through tubular mem- - stream and D is a similar slip line with the Brownian of paper which is cut simultaneously with movement the particle denoted by the wavy line F the roving Better the encasing material may be formed superimposed thereon It is clear that if the smoke par- into a shape as by the use of a suitable mandrel the ticle is to be removed from the air stream it must impinge roving deposited thereon and the through or collide with the fiber In the a tubular die member wherein edges of the material roving possibility of collisions are obviously remote One solution problem would be to accelerate the particle to the air .. are brought together overlapped and secured the . being simultaneously compressed to provide the specified such an extent that it would be thrown from stream E to- " gravity In additional me- - due to its greater inertia into a straight line path ". chanical may be imparted to the roving when . ward the surface of However such a high under the - with cotton thread or the linear speed manifestly could never be realized indicated braiding the same material to the 20 conditions involved in the problem to which the invention like or by or bonding is addressed -- - , fibrous mixture bind together the individual fibers or herein of attack would be to increase the a substantial proportion of them at their intersections to " Another angle -rende filr ter firm and resilient while retaining its loose ber of fibers in of the particle by closer packing through this tight uncompacted nature without impairment of draw Ther- - of the fibers and to pass the particle it would be bound to collide with moplastic or thermosensitive as synthetic 25 maze so slowly that due diffusion effect Obviously preferably having a softening or activa- one of the fibers to a because of the ... resinous tion point of -300 F. may be applied to the fiber this approach is also out of the question mixture in the form of dry solid particles liquid drop- limiting conditions here involved _ lets or a solution or dispersion a liquid medium If . The invention will be described with reference to cershown in the appended drawings in . desired the binder material may itself take the foromf a 30 tain embodiments : fibrous material and may replace part or all of either the small diameter or the carrier fibers When a thermo- - Fig 1 is a schematic representation of the path of a _ plastic or thermosensitive binder is employed either in - smoke particle past a fiber of large diameter a the form of fibers otherwise a subsequent heating step . Fig la a similar representation of a path of a smoke - is required activate it and bond togetheart 35 particle past a fiber of small diameter intersections to stabilize the fibrous mass in its loose Fig 2 is an elevation partly broken away and in sec- uncompacted form having required apparent density tion showing the filter of the present invention embodied to . When the binder material is applied the fiber mixture in a cigarette . | embodiment of 7 care should be exercised to avoid coating the small di- Fig 3 is an end elevation of another ; so to ameter fibers increase their diameters above the of _ specified size The proportion binder material to the . total fiber mixture is usually about -25 by weight critical . preferably about 15 by weight . ; is to be clearly understood that the previously stated range on small diameter concentration is not ; 40 my invention Fig 4 is a view in elevation partly broken away and in . view elevation smoking ~ section of a tion and _. Fig 5 is a pipe embodying the present inven- | partly broken away and in section of a cigarette holder embodying the present ' for I may include either a substantially higher or a sub- invention of . . stantially lower proportion of such fibers Even with Fig 1a is representative of the mechanism of the filtra- _ * amounts as low as % I can effect a distinct improvement tion as effected according to the invention Here A -. over crepe paper cotton filters for example How- . is the smoke particle B is a section of a small diam- . ever for best results the content of small diameter fibers eter fiber preferably an asbestos fiber having a diameter D'are . 0.1 0.m6icron should not be much less than about % approaching that of the smoke particle and and D'are fiber mixture at . by weight of the total preferably least _ slip lines as in Fig 1 wavy line F denoting the Brownian the of of _. % Depending upon the demand concentration movement the particle as in that figure In this in- slip lines - small diameter fibers in some cases may be as high as stance the displacement of the around the fiber the . or higher than 30 despite the fact that at this point 55 is very slight indeed and as a consequence particle is fiber definite impairment tobacco - there is of taste and flavor almost certain to collide with the and be removed In the case of filter masses including from 5 % 30 by " from the air especially when one considers the present from weight of small diameter fibers there will be " 70 to 95 by weight of carrier fibers having a diameter " resulting from deviation the Brownian movement Moreover it should be pointed out that the particle cotton on the order of fibers Such a filter mass prefer- 60 in Fig 1a would not need to be accelerated to nearly resistance draw ablyhas substantially no greater to than as high linear speed as the particle in Fig 1 before the of an equal volume the cigarette tobacco inertia ofthe particle would cause it to deviate sufficiently diameter fibers ,. The importance of using anall of the from the path represented by the slip lines to bring about . diameter indicated cannot be overly emphasized Fibers its collision _ fiber filter with the - of greater diameter are relatively ineffective while smaller 65 The carrier fibers combined in my serve to main- diameter fibers have the disadvantage of contributing dis- tain the structure sufficiently open to allow for easy absence thereof _ proportionately to the air resistance and so are practically passage air In the the density of . ; . inoperable a the filter would be such that it would be virtually im- Tobacco smoke as well understood represents a disper- sion possible to draw any smoke through it As most pref- liquid particles sion of solid and ~ | extremely stable erably manufactured being in air the dispersion 70 by reason of the small size of the the resistance of the filter is sub- no greater than which makes of gravity negligible stantially the volume of tobacco as con- the effect under _ particles effect of convection currents and tained in a cigar cigarette or pipe Even these with _ compared the ; .. Brownian movement - os conditions upwards of -50 of the tars and nicotine 7 The manneirn which my invention works is perhaps 75 are effectively removed 2,761,798 Forms which my invention may take are illustrated in Figs 2 to in which the filter material is indicated by the numerals 10 10 10 and 10 respectively and may be assumed as combining cotton fibers or other fibers as the carrier fibers and Bolivian blue asbestos as the small di- & ameter fiber component such asbestos being particularly preferred for use according to the invention In Fig 2 the material is shown encased within a cigarette tip 12 which . may simulate ivory or cork for example the tip having a slightly greater diameter exaggerated in the drawing than the body 14 of the cigarette and being secured thereto by means of a suitable adhesive In this em- bodiment the fibrous mass 10 is in the form of a roving having the carrier fibers generally oriented in the direc- tion of travel of the tobacco smoke Fig 3 affords an enlarged end view of a cigarette construction in which the filter materiailn the form of a loose fibrous web 10 is distributed in the folds of a conventional crepe paper filter 16 relatively loosely formed As shown in Fig 3 the crimps of the crepe paper extend generally in the direction of travel of the tobacco smoke This increases the efficiency of such a paper filter not less than 500 assuming a weight ratio as between the fibrous filter ma- terial comprising -20 small diameter fibers and the crepe paper of approximately 2 The filter construction in the pipe represented by Fig 4 is shown as including a paper casing 18. A cloth casing for example either finely woven or open mesh may be substituted The filter disposed in the cigarette holder of Fig 5 30 is also shown as including a casing 20 of paper or equivalent material Because of the greater efficiency of the filter it becomes loaded with tars and nicotone much sooner than conventional filters and accordingly should be changed more often 35 But the filter even after the smoking of say ten cigarettes is still upwards of 200 more efficient than a conventional filter freshly inserted in the holder ; This application is a continuation in part of my parent application Serial No. 260,187 filed December 6 1951 now abandoned and of my copending application Serial No. 384,673 filed October 7 1953 Although I have herein described specific embodiments of my invention I do not intend to limit myself solely thereto but to include all of the obvious variations and modifications within the spirit and scope of the appended claims I claim 1. A tobacco smoke filter comprising a loose mass of intermingled fibrous material having an apparent density from 0.1 to 0.23 gram per cubic centimeter said mass including a predominant proportion of carrier fibers and a lesser proportion of small diameter fibers said carrier fibers having a diameter on the order of cotton fibers and said small diameter fibers having a diameter corresponding to the diameter of the smoke particles to be removed and being of the order of 0.1 to 0.6 micron 2. A cigarette having a filter member for removing a substantial amount of the tars and nicotine from the smoke from said cigarette said filter member comprising a loose mass of intermingled fibrous material having an ~ apparent density from 0.1 to 0.23 gram per cubic centimeter and having substantially no greater resistance to draw than an equal volume of the cigarette tobacco and said mass including from 70 to 95 by weight of carrier fibers having a diameter on the order of cotton fibers and from % to 30 by weight of small diameter fibers having a diameter corresponding to the diameter of the smoke particles to be removed and being of the order of _ 0.1 to 0.6 micron No references cited Sept. 4 1956 H. W. KNUDSON FILTER FOR TOBACCO SMOKE Filed April 24 1956 2,761,798 UGLISPLLE ODETTE