US 2881769 A
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April 14, 1959 G'. P. TOUEY FIBROUS CIGARETTE FILTERS Filed March 3, 1954 FIG 1 JTAIPCH PART/0.455
F/L TER WRAPPER TOBACCO FIG Z CIGARETTE WRAPPER R m H. F
ATTORNEYS P W w E R. 2% G w United States Patent FIBROUS CIGARETTE FILTERS George P. Touey, Kingsport, Tenn., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Application March 3, 1954, Serial No. 413,950
7 Claims. (Cl. 131-408) The present invention relates to tobacco smoke filtering material and elements thereof suitable for use in cigarettes, pipes, cigarette holders, and cigar holders. More particularly, the invention is concerned with an improvement in filters of the general type disclosed in US. Patents No. 2,794,239 and No. 2,794,480, both issued June 4, 1957 to Crawford and Stevens.
In the aforementioned applications, newly discovered advantages of a certain type of fibrous tobacco smoke filter are discussed. The filter is prepared from a specially conditioned tow of synthetically spun continuous filaments and comprises a structurally unitary rod-like mass of fibers and a wrapper encircling the mass, each fiber of the mass being substantially co-extensive therewith, the fibers as a whole being in substantial alignment longitudinally of the mass but substantially each of the individual fibers having a plurality of short portions thereof crimped into diverging and converging relationship to the main fiber axis, a plurality of the fibers having surface solvation bonds to contiguous fibers at random points of contact. Very good results have been obtained in the use of such filters for the removal of nicotine and tars from tobacco smoke, especially in view of the fact that the filters supply other requirements equally as necessary to the success of a tobacco smoke filter.
These filters also have a marked processing advantage over other filters known in the art. However, since the fibers in such filters are all parallel to each other, some channeling of the smoke through the filter may be possible, resulting in a decreased'filtering action.
In other words, while interference with the smooth flow of combustion products through the channels is provided by the random bonds between adjacent fibers, by the incompleteness of fiber orientation, and by the short fiber portions which are crimped into diverging and converging relationship to the main fiber axis, yet a certain amount of the smoke in the core of any minute column of smoke passing through the filter apparently can escape a necessary minimum contact with the fiber surfaces. Experimental investigations have shown that any attempt to reduce the size of smoke channels through the filters by an increase in filter density either through greater compaction or through the use of finer fibers generally also results in an intolerable increase in pressure drop through the filter.
I now have found that the efiiciency of the filters described may be substantially increased without equivalent increase in pressure drop through the filter by depositing certain finely divided solids in the smoke channels provided by the spacing of adjacent fibers. I further have discovered that when vegetable starch is employed as the finely divided deposit, unusual efficiency is obtained.
This invention, therefore, has as one object the production of a more efficient cigarette smoke filter consisting of a bundle of substantially longitudinally oriented textile fibers infused with finely divided vegetable starch powders. Another object is to provide means for increasing the efficiency of a cigarette filter prepared from ice a textile fiber. A still further object is provision of a filter which is capable of removing nicotine, tars, and other deleterious components of cigarette smoke without causing the smoke to be dry or distasteful. Another object is to increase the elficiency of tobacco smoke filters of the Crawford and Stevens application without creating a high pressure drop. Other objects will be obvious from the present specification and claims.
Accordingly, the present invention consists, in general, in a tobacco smoke filtering medium comprising a mass of substantially longitudinally aligned fibers, the spacing of substantially all groups of adjacent fibers providing minute passages for smoke therethrough, said mass carrying therein starch particles in an amount of 1 to 60% by weight of the mass and said particles occupying positions in and partially blocking said passages whereby a substantial portion of the smoke is impinged either on the fibers or on the starch.
A more specific embodiment of the invention comprises a new tobacco smoke filtering material of synthetically spun continuous filaments and an element made therefrom, the element comprising a structurally unitary rod-like mass of fibers and a wrapper encircling the mass, each fiber of the mass being substantially coextensive therewith, the fibers as a whole being in substantial alignment longitudinally of the mass but substantially each of the individual fibers having a plurality of short portions thereof crimped into diverging and converging relationship to the main fiber axis, a plurality of the fibers having surface solvation bonds to contiguous fibers at random points of contact, the mass carrying substantially uniformly dispersed therein a solid finely divided vegetable starch in the amount of 1 to 60% by weight of the mass.
Most advantageously, the invention comprises a filter of cellulose acetate fibers having surface solvation bonds achieved through the application of a plasticizer spray, the filter carrying uniformly dispersed starch particles in the amount of about 10 to 40% by weight of the filter.
The invention is illustrated in the accompanying drawings in which Figure 1 represents a magnified view of the interior of a mass of filtering material prepared in accordance with the invention, and
Figure 2 is a view of a cigarette having attached thereto a tip prepared from a filtering material of the invention.
Any suitable means known to the art for spreading a powder onto a fibrous surface or through a fibrous mass may be employed in preparing filters of the invention. Thus, for example, the starch powder can be blown onto the fibers or it can be applied as a slurry in cold water or in an organic solvent or plasticizer. Another method is to apply the starch powder to the fibers electrostatically, i.e. to induce a charge on the fibers by friction or other suitable means and then to run the fibers through a chamber containing highly concentrated starch dust. Still another method for applying the starch is to wet the surface of the fibers with an adhesive or a plasticizer before exposing them to a powder spraying device. Preferably, the starch is continuously applied to an opened and banded moving tow formed as described in the Crawford and Stevens applications. That is to say, tow from a supply roll is opened to debundlize the filaments and provide a larger and more uniform tow cross section, and the opened tow is spread uniformly to a much larger width of e.g., 7 times its original width, thereby exposing substantially all of the filaments to material, i.e. plasticizer, issuing from a dispenser under which the tow passes. The starch may be added before, simultaneously with, or after the plasticizer, preferably with or after.
Example 1 A partially opened tow of cellulose acetate yarn containing approximately 20,000 fibers of five denier per filament was slowly pulled over a compressed air banding device as disclosed in the aforementioned Crawford and Stevens patent applications which momentarily spread out the fibers to a width of six inches. While the tow was in this spread condition it was sprayed with a highly agitated slurry of one part of a commercial brand of powdered corn starch in five parts dimethoxyethylphthalate plasticizer. After this spreading and spraying treatment the tow was pulled back to its original shape of a cord and fed into a conventional cigarette make-up machine which wrapped it with paper and cut it into rods similar in size to a standard size cigarette. The rods contained 1 part starch, 5 parts plasticizer and 25 parts cellulose acetate by weight. After the filter rods were given a short heat treatment to cause partial solvation of the acetate fibers by the plasticizer they were readily cut into 12 mm. filter tip lengths. These tips were attached to a standard brand of cigarettes available on the retail market in the U.S. by means of an adhesive tape and the cigarettes were smoked on a smoking machine similar in design and operation to the smoking machine described by J. A. Bradford, W. R. Harlan and H. R. Hanmer in Industrial and Engineering Chemistry, vol 28, pp. 836-9 (1936). The collected smoke was analyzed for nicotine and tars. The results of the smoking experiment were compared with those obtained from smoking the same brand of cigarettes containing 12 mm. filter tips made from the same tow of cellulose acetate fibers plasticized with dimethoxyethylphthalate without the ad- Moisture of the tobacco in each of the cigarettes=l1.8%. 1 Obtained from the collected smoke of ten filtered cigarettes.
Example 2 A loose, i.e. partially opened tow of cellulose acetate yarn containing approximately 10,000 fibers of 8 denier per filament was pulled through a bath containing a highly agitated slurry of 15% commercially available starch powder in cold water. When dried, the tow contained 14% of starch by weight uniformly dispersed throughout. The starch impregnated tow was processed into filter rods according to the method described in Example 1 and the rods were cut into 12 mm. lengths. tips so produced were attached to standard brand cigarettes and ten of these filter tipped cigarettes were smoked on the smoking machine. The collected smoke was analyzed for nicotine and tars. A control, consisting of the same brand of cigarettes tipped with filters made from the 8 denier per filament tow containing no starch was also smoked on the smoking machine and the collected smoke was analyzed in the same manner for nicotine and tars.
Moisture of the tobacco in each of the cigarettes=l2.l%.
Example 3 A tow of cellulose acetate yarn containing approxi- The filter mately 40,000 fibers of 3 denier per filament was spread out to a width of six inches and sprayed with a 10% solution of a water-base adhesive. While the tow was still spread out and wet with the adhesive it was sprayed with a commercially available finely divided dry corn starch powder and then rolled back into its original form. The impregnated tow was processed into filter rods and the rods were cut into 12 mm. lengths. The filter tips, containing 9% starch based on the weight of the acetate fibers, were attached to standard brand cigarettes and ten of these cigarettes were smoked onthe smoking machine.
mg. of mg. of
tars nicotine Acetate tow filter 19 Acetate tow filter containing 9% starch 98 13 Moisture oi the tobacco in each of the clgarettes=l2.0%.
In carrying out the operation of thisinvention the type of starch employed is not a, critical factor. Rather, the form of the starch is more important. The starch should be in a powdered form so that it can be readily slurried' in a liquid or passed through a spraying nozzle. Any source of starch which passes this requirement can, there-' fore, be employed. Such commercial starch powders as corn, wheat, potato, rice, and tapioca starch may be employed. Also, the oxidized starches may be used. In addition such starch derivatives as dextrin, and the various forms of hydrolyzed starches may also be used.
While unusually good results have been obtained with filters prepared from a crimped continuous filament tow of cellulose acetate fibers sprayed with a plasticizer, e.g.' dimethoxyethyl phthalate or methylphthalylethylglycollate, it will be recognized by those skilled in the art that the usefulness of the invention extends to other fibrous filters, including those prepared from fibers of viscose, cotton, nylon, polyamides, polyesters, etc., particularly where the fibers are in substantial longitudinal alignment and are coextensive with the body of the filter.
1. A tobacco smoke filter adapted to removecertain undesirable components from tobacco smoke, said filter being comprised of a bundle of continuous, longitudinally aligned filaments in which substantially all of the filaments extend through the full length of the filter from end to end, said filaments being essentially comprised of cellu lose acetate and a plasticizer therefor, said filaments carrying on their surface solid finely divided vegetable starch substantially uniformly dispersed over the surface ofthc filaments and a wrapper around the circumeference of said bundle.
2. A filter in accordance with claim 1 wherein the bundle of filaments is comprised of several thousand filaments of a denier per filament not greater than 8.
3. A filter in accordance with claim 1 wherein the amount of plasticizer by weight is greater than the weight of the finely divided starch which is uniformly dispersed on the filaments.
4. A filter in accordance with claim 1 wherein the plasticizer is an ester.
5. A filter in accordance with claim 1 wherein the per centage by weight of the finely divided starch with re spect to the weight of the filaments 'is from about 31% to 14%. i
6. A'filter in accordance with claim lxwherein the finely divided starch is rice starch. t
7. A tobacco smoke filter adapted to remove certain undesirable components from tobacco smoke, said filter consisting essentially of abundle of'at'ileast 10,000 longi' tudinally aligned synthetic thermoplastic filaments of a denier per filament less than 8 and in which substantially all the filaments extend through the full length of the filter from end to end, said filaments carrying a content of a material that will facilitate the bonding of a powdered solid to the filaments, a content in the amount of from 10%40% by weight of the filter of finely divided vegetable starch solid material substantially uniformly dispersed on the surface of the filaments, and a wrapper around the circumference of said bundle.
References Cited in the file of this patent UNITED STATES PATENTS 964,489 Campo July 19, 1910 1,809,529 Pettibone June 9, 1931 2,171,770 Strauch Sept. 5, 1939 2,331,830 Garber Oct. 12, 1943 6 Browne et a1 July 19, 1949 Francis Oct. 4, 1949 MacHenry Sept. 7, 1954 Taylor et al. May 3, 1955 Von Reis et al. Oct. 25, 1955 Lieser Mar. 27, 1956 Jacobs et al. June 19, 1956 Knudsen Sept. 4, 1956 Hackney et a1 Dec. 18, 1956 Taylor et al Apr. 23, 1957 FOREIGN PATENTS Great Britain 1909 Australia Feb. 25, 1954 Great Britain Dec. 24, 1935 Great Britain Aug. 7, 1941 Great Britain Jan. 23, 1952 France Feb. 22, 1937