US2904050A - Tobacco smoke filtering elements - Google Patents

Description

Sept. 15, 1959 J. E. KlEFER ETAL 2,904,050

TOBACCO SMOKE FILTERING ELEMENTS Filed Jan. 5, 1955 Fig.

CELLULOSEACETATE F/LAMENTS (2D/F/LAME/VT) CONTAIN/N6 WAX PARTICLES Fig.2

TOBACCO SMOKE FLOW CELLULOSE ACETATE F/LAMENT CO/VTA/AT/NG WAX PARTICLES JOHN E. K/EFER GEORGE I? TOUEY INVENTORS A TTOR/VEYS 2,904,050 TOBACCO SMOKE FILTERING ELEMENTS John E. Kiefer and George P. Touey, Kingsport, Tenn.,

, assignors to Eastman Kodak Company, Rochester,

N.Y., a corporation of New Jersey Application January 5, 1955, Serial No. 480,059 Claims. (Cl. 131-208) Unitcd States Patent ing media. However, some fibrous materials have certain disadvantages either from the standpoint of their fabrication into filters or their undesirable effect on the taste of thesmoke. For example, cotton and paper cannot be too-conveniently processed by conventional cigarette machinery into a form that can be readily cut into filter tips and added to the. end of 'a cigarette. vAnother disadvantage of tobacco smoke filters made from cotton or paper is that moisture is absorbed quite readily by the filter which makes the smoke too dry.

The use ofcertain textile fibers and in particular fibers of cellulose ester, overcomes to a great extent the aforementioned fabrication difiiculties ,encountered--,with cotton or crepe paper. That is, textile fibers can be manufactured: in a formthat is easily converted by, reasonable conventional cigarette processingequipment into filter; tips which can 'be used for tobacco smoke filtering purposes. Thus, for example, it is possible to orient a large number of cellulose acetate fibers into the form of a continuous cord whichv is commonly known to .the trade as a tow. Such tow can be plasticized, cut, and wrapped in cigarette paper to form filter rods; with great rapidity on -a filter make-up machine. These filter rods are then easily out into tipsof the desired length and placed on the ends of cigarettes. While, as just mentioned, textile tow has certain advantages for manufacturing tobacco smoke filtering elements, in some instances the resultant filter has not possessed as much stifiness or firmness as desired. Also, there has been some tendency of textile fibers to become soft or soggy due to the absorption of moisture from the tobacco smoke.

After investigatingwe have found that fibrous ma terials, particularly a crimped cellulose ester typeof tow material may be treated in a simple manner to render it possible to obtain an improved tobacco smoke filter therefrom This invention therefore has as one object the production of more efiicient tobacco smoke filter elements consistingof a bundle of crimped substantially longitudinally oriented textile fibers, containing a wax additive. Another object is to provide means for increasing the ability of the tobacco smoke filter of the class described to remove more nicotine, tars and other undesired components of tobacco smoke without causing the smoke to be dry or distasteful. --Still another object is to provide an oriented type of tobacco smoke filter element which is stifier, more firm and otherwise possesses qualities mak- 2,004,050 Patented Sept. 15, 1959 ing' it easier to process in conventional filter make-up machmery. Still a further object is to provide an improved tobacco smoke filter of textile tow which while exhibiting good filtering qualities does not tend to become soft and soggy. A particular object of this invention is to provide a procedure for incorporating wax into cord or tow tobacco smoke filtering elements. Other objects will appear hereinafter.

i We have found that the continuous cord or tow type of textile fiber can be substantially improved for tobacco smoke filtering purposes by adding to the crirnped tow orcord a certain amount of wax. That is, our improved tobacco smoke filter of the present invention consists gene'rally of a mass of substantially longitudinally aligned crimpedcellulose ester fibers, the spacing of substantially all groups of adjacent fibers providing passage for tobacco smoke therethrough, said fibers carrying thereon a certain amount. of wax usually between 130% based on the weight of the fibers.

Various means andprocedures may be used for coating the fibrous surfaces with wax. Thus, for example, wax can be heated to its melting point and sprayed on the fibers. Another. method is to draw the fibers through a bath containing molten Wax. Still another method is to deposit solid Wax on the cord or tow and then heat treat the cord .or tow to melt and diffuse the wax evenly on and throughout the filter element.

.for a further understanding of certain aspects of our invention reference may be made to the attached drawin g forming a part of the instant application.

In this drawing, Fig. 1 is a diagrammatic illustration ri a considerably enlarged scale of a segment of a plurality of crimped continuous cellulose acetate filaments carrying particles of waxy material on the filaments in accordance with the present invention. .FiggZ is a diagrammatic illustration on a considerably enlarged scale of a single crimped cellulose acetate filamerit carrying Wax particles thereon in accordance with the present invention.

Referring further to Fig. 1, the plurality of individual cellulose acetate filaments are shown at 1, 2 and 3. These filaments -are'substantially continuous, only a segment of a small group of such continuous filaments being illustrated in the figure. These filaments contain distinct crimps as illustrated at points 4 and 5, for example. The filaments carry particles of waxy solids firmly bonded 'to the filaments as disclosed at 6 and 7, for example. The several thousand filaments making up a filter would be intermingled in the rod-like filter element substantially similar to the intermingling diagrammatically illustrated in Fig." 1.1 I Reference is now made to Fig. 2 wherein a segment of a single continuous filament is illustrated. This figure better shows some of the features referred to above. For example, in this figure, numeral 11 designates the cellulose acetate filament. The peak of a crimp is generally indicated at point 12. The'solid waxy particles which are carried by the filament, which particles are firmly bonded thereto, are illustrated, for example at 13 and 14.

In carrying out any of the above methods, it is usually desirableto spread the fibers out to a width of several inches by any suitable method for facilitating the uniform application of the wax to all of the fibers. After the fibers have been properly coated with wax, they are then gathcred together into the desired configuration for the filter and'wrapped with a wrapper or otherwise somewhat more permanently formed and held in the desired shape. These latter operations of forming the fibers into the filter element may bevery readily accomplished in conventional machinery. In other words, our wax treated fibers may be better formed into tobacco smoke filtering elements 3 than the untreated fibers heretofore processed in such machinery.

' In carrying out our invention, we have found that various types of waxes may be used. Thus, vegetable, petroleum, insect, animal, mineral, and synthetic waxes are in general satisfactory; More specifically, some of the waxes which we have found particularly useful and prefer are as follows: (a) Carnauba wax.-This is a vegetable wax and consists chiefly (about 75 of myricyl cerotate, a small quantity of free 'cerotic acid, and myricyl alcohol. The physical properties are: melting point, 84-91 C.; specific gravity, 0.99; acid number, 4-9; saponification number, 78-87; soluble in'hot alcohol and in benzene, ether dioxane, and isopropyl ether.

'(b) Parafiin'.This is a petroleum wax obtained from the high boiling fractions of petroleum. It is a mixture of a great number of saturated hydrocarbons. Its physical properties are: melting range, 43-66 C.; specific gravity, 0.88-0.92 at ordinary temperatures; acid number, saponification number, 0; soluble in benzene ether, chloroform, and turpentine.

' '(c) Beeswax.This is 'an insect wax. Chemically, it

is composed of myricyl palmitate, cerotic and homologous acids, and small amounts of hydrocarbons, cholesterol esters, ceryl alcohols, pollen, and'resins. The physical properties are: 'melting point, 63-70 C.; specific gravity, 0.95 2-0L957; acid number, 16-20; saponification number, 90-96; soluble in benzene, carbon tetrachloride, chloroformfdioxane, acetone, and ether.

(d) Spermaceti.This is an animal wax obtained from the sperm whale. It is composed of cetyl palmitate, cetyl alcohol, and numerous esters of high-molecular weight fatty acids. The'physical properties are: melting point, 42-49" C.; specific gravity, 0945-0960; acid number, 0.5-1.1; saponification number, 122-129; soluble in hot alcohol, ether, chloroform, and carbon disulfide.

'(e) M0ntai1.This is a mineral wax obtained by sol vent extraction of woody coals or lignite. It is a monohydric ester of a'high-molecular weight acid. The physical properties are: melting point, 72-92 C.; specific gravity,l.0.; acid number, 15-85; saponification number, 58-89; soluble in' benzene, chloroform, naphtha, and isopropyl ether.

f) High-molecular weight acids and alcohols-A number of alcohols and acids havewax-likeproperties. These include cetyl and stearyl alcohols and stearic, palmitic, and myris'tic acids.

(g) High-molecular weight esters-The stearates of polyhydric'alcohols, such as ethylene glycol and diethylene glycol are high-molecular weight products of a waxlike nature.

(h) Carb0waxes.-'Ihese are synthetic Waxes sold by Carbide and Carbon Chemicals Company and comprise a series of high-molecular weight polyethylene glycols. These waxes have a melting point range of 34-55 C. and a density range of 1.15-1.20. They are water-soluble.

"(i) Acrawaxes.These waxes are produced and sold by Glyco Products Company in threegrades: Acrawax, Acrawax B, and Acrawax C. They are complex nitrogen derivatives of high-molecular weight fatty acids. The physical properties of these three waxes range as follows: melting point, 95-139 C.; specific gravity, 0.98-1.05; soluble in hot toluene, turpentine, and mineral oil.

(j) CastorWam-This is a hydrogenated castor oil produced and sold by Baker Castor Oil Company. The physical properties are: melting point, 86-88 C.; saponification'number, 175-185; acid number, 2; insoluble in most solvents.

(k) P0lyethylerte.-Tl1isis a high-molecular weight polymer of ethylene being produced by a number of chemical companies. It s melting point is l05-110 C. It is soluble in hot benzene and toluene but insoluble in practically all organic solvents in the cold,

Thus, irrespective of the particular method used of applying the wax, or the particular wax used, the fibers are readily wrapped in conventional equipment to form a smoke filtering element. The resultant filter element comprises a structurally unitary rod like mass of fibers with a wrapper encircling the mass, each fiber of the mass being substantially coextensive therewith, the fibers as a whole being all substantially aligned longitudinally of the mass. However, substantially each of the individual fibers has a plurality of short portions thereof crimped into diverging and converging relationship to the main fiber axis. A plurality of the fibers have surface bonds to contiguous fibers at random points of contact. This bonding may be accomplished either through the presence of plasticizer or the wax or a combination of wax-plasticizer.

As indicated above, we prefer to use in the instant invention fibers of cellulose esters and particularly cellulose acetate fibers which have a certain amount of crimp and have the property of bonding to some extent .to adjacent fibers, either because of the thermoplastic properties of the fibers or the addition of plasticizer or the presenceo f wax of the present invention, or by combiriation of the foregoing.

For a further understanding of our invention reference may be made to the following examples which are set forth primarily for the purpose of disclosing our preferred embodiments. Y

" v Example I A tow of cellulose acetate yarn containing approximately 20,000 fibers of five denier per filament was slowly pulled over a compressed air device which spread out the fibers to a width of six inches. While the tow was in, this spread condition it was sprayed with a molten petroleum wax heated to C. After this spreading and spraying treatment, the tow was pulled back to its original shape and fed into a conventional cigarette make up machine which cut and paper-wrapped it into rods of 8.1 mm. diameter and 71 mm. length. The rods contained 24 parts wax and 76 parts cellulose acetate by weight. The rods were cut into 12-min. filter tips. These tips were attached to standard American cigarettes by means of an adhesive tape (Scotch tape) and the cigarettes were smoked on a smoking machine similar in design and operation tothe smoking machine described-by J. A. Bradford, W. R. Harlan, and H. R. Hammer in Industrial and Engineering Chemistry, vol. 28, pp. 836-9 (1936). The results of the smoking experiment were compared with those obtained from smoking the same brand of cigarettes containing 12-min. filter tips of the same tow of cellulose acetate fibers without the addition of the wax.

Mg. of tars Mg. ofnieobtained otine obfrom the tained from Type of cigarette tip (12 mm.) collected the colsmoke of lasted- 10 filtered smoke of 10 cigarettes filtered cigarettes Cellulose acetate tow 132 20 Cellulose acetate tow containing 24% petroleumwax 107 18 through one cigarette. On this basis, the average prestnre drop of the above cigarettes with a filter-of cellulose acetate tow was 4.0 inches ofwater; the average pressure drop was 4.3 inches of water when a filter of cellulose acetate tow With 24% wax additive was tested.

Example In accordance with this example, cellulose acetate tow approximately the same as that described in Example I was spread by means of compressed air. The spread tow was treated with a wax known as castor wax to the extent of about'24% of the weightof the fibers. Thereafter the castor wax treated fibers were fed into conventional mafiltered cigarettes were smoked on the smoking machine.

chin'ery for forming and wrapping the fibers into filter elements. The filter elements were attached to cigarettes and tested in the smoking machine. The test indicated that the wax treated filters 'of the present invention improvedthe removal of undesired compounds. That is, 7% more tar was removed with the filters of the present invention as compared with a filter that had no wax treatment; This was some 25% greater tar removal than with 'a regular cigarette having no filter whatsoever. In addittion to giving improved removability of tar, the filters of the present invention were firmer and stifier than prior art filters. This firmness persisted throughout the smoking operation and the filters of the present invention did not become soft and soggy.

Examplef LIII A tow of cellulose acetate yarn containing approximately 10,000 filaments of 8 denier per filament was slowly pulled over a compressed air device which spread out the fibers to a width of six inches. While the tow was in this spread condition, it was dusted with powdered (300 mesh) stearic acid. After this spreading and dusting treatment, the tow was pulled back to its original shape and fed into a conventional cigarette make-up machine which cut and paper Wrapped it into rods of 8.1-mm. diameter and 71-11'1111. length. The rods contained 25 parts stearic acid and 75 parts cellulose acetate fibers by weight. These soft rods were heated at 85 C. for ten minutes (melting point of stearic acid, 69-70" C.) 'in a drying oven and then allowed to return to room temperature. On cooling, the rods became quite firm. These firm rods were cut into l2-mm. filter tips. These tips were attached to standard American cigarettes by means of a cellulose tape and the cigarettes were smoked on the smoking machine. The results of the smoking experiment were compared with those obtained from smoking the same brand of cigarettes containing l2-mm. filter tips of the same tow of cellulose acetate fibers without the addition of the wax.

Average pressure tained drop of from the the cigarcollected ettes smoke of (inches of 10 filtered water) cigarettes Mg. tars obtained from the collected smoke of 10 filtered cigarettes Mg. nicotine ob- Type of cigarette tip (12 mm.)

Cellulose acetate tow Cellulose acetate tow containing 25% stearic acid It can be seen from this Example III that the filter containing the stearic acid wax removed substantially more tar and nicotine than the corresponding control filter without the Wax. Also, this filter was firmer and did not become soggy.

Example IV The results of the smoking experiment were compared with those obtained from smoking the same brand of ciggarette containing 12-min. filter tips of the same tow of regenerated cellulose without the addition of the wax.

Mg. nicotine ob- Average pressure drop of the cigar- Mg. tars obtained from the collected smoke of 10 filtered cigarettes tained from the collected smoke of 10 filtered cigarettes Type of cigarette tip (12 mm.)

' ettes (inches of water) Regenerated cellulose tow Regenerated cellulose. tow conta mg 18% carnauba wax 3 While we prefer to manufacture our filter from crimped,

oriented, longitudinally positioned cellulose acetate fibers, we have found that the wax improves (other types of fibers such as viscose fibers.

We claim:

1. A tobacco smoke filtering element comprised of a unitary rod-like bundle of at least 10 ,000 continuous cellulose acetate filaments, the bundle being approximately 8.1 mm. in diameter, the filaments of the bundle being longitudinally aligned and coextensive with the length of the filter element, and the filaments having nonoriented short portions thereof crimped into diverging and converging relationship to the main filament alignment, the spacing of the adjacent aligned continuous filaments providing longitudinal passages for smoke through the bundle, the filter element being further characterized in that the aforesaid filaments carry and have relatively uniformly distributed on the surfaces of the filament 130% by weight of a wax.

2. A tobacco smoke filtering element comprised of a structurally unitary rod-like bundle of at least 10,000 continuous cellulose acetate filaments of a denier of approximately 5-8 per filament, 130% by weight of a wax uniformly deposited on the surface of the filaments and a wrapper encircling the bundle, each wax-covered filament of the bundle being substantially co-extensive with the length of the filter element, the filaments as a whole being in substantial alignment longitudinally of the filter element and each of the individual filaments of the bundle having a plurality of short portions thereof crimped into diverging and converging relationship to the main filter element axis, the spacing of groups of adjacent continuous filaments providing longitudinal passages for smoke through the bundle, the wax occupying positions in and partially blocking said passages.

3. A filter element in accordance with claim 2 wherein the wax is parafiin wax.

4. A filter element in accordance with claim 2. wherein the Wax is castor wax.

5. A tobacco smoke filtering element comprised of a rod-like bundle of at least several thousand continuous crimped synthetic filaments of a denier per filament not greater than 8, l30% by weight of a wax in the form of finely divided particles substantially uniformly disposed on the surface of the filaments and a wrapper encircling the bundle, each wax-covered filament of the bundle being substantially coextensive with the length of the filter element, the filaments as a whole being in substanalignrnentlongitudinally of'the filter element and each of the individual filaments. of the bundle having a plurality. of: short portions thereof crimped into diverging and. converging relationship to the main filter element axis, the spacing of groups of adjacent continuous filaments. providing longitudinal passages for smoke through the bundle, the wax occupying positions in and partially blocking said passages.

6. A tobacco smoke filtering element comprised of a rod-like bundle of at least several thousand continuous crimped. cellulose acetate filaments, 130% by weight of wax in the form of finely divided. particles disposed on the surface ofi the filaments and relatively firmly bonded thereto and a wrapper encircling the bundle, each waxcovered filament; of the bundle being substantially coextensive with the length of the filter element, the filaments as a whole being in substantial alignment longitudinally of the filter element and each of the individual filaments of the bundle having a plurality of short portions thereof erimped into diverging and converging relationship to the main filter element axis, the spacing of groups of adjacent continuous filaments providing longitudinal passages for smoke through the bundle, the wax occupying positions in and partially blocking said passages.

7 z A filter element in accordance with claim 6 wherein the finely divided wax is from the group consisting of carnauba, parafiin, bees, spermaceti, montan, carbo, acra, castor and polyolefin waxes.

8. A filter element in accordance with claim6 wherein the wax is a stearyl alcohol.

9. A filter element in accordance with claim 6 wherein the wax is a polyolefin wax.

10. A filter element in accordance with claim 6 wherein there is a content of plasticizer present.

References Cited in the file of this patent UNITED STATES PATENTS 1 Demouth Oct. 15, 1889v Sundheim Mar. 10, 1896 Linnekogel Nov. 4, 1902 Minton July 25, 1933 Reed Apr. 5, 1938 Strauch Sept. 5, 1939 Neville et al. July 9, 1940 Knewstubb et al. July 3, 1951v MacHenry Sept. 7., 1954 Taylor et a1 May 3, 1955 Von Reis et al Oct.25, 1955 Jacobset al. June 19, 1956 Hackney et al Dec. 18, 1956 Taylor et al. Apr. 23, 1957 FOREIGN PATENTS Great Britain June 13, 1929 Great Britain May 25, 1949 OTHER REFERENCES Matthews: Textile Fibers, pages 266, 207, 267 and 268,

published 1947 by John Wiley & Sons, Inc., New York.

The Modern Textile Dictionary, by G. E. Linton, page 5; published 1954 by Duell, Sloan and Pierce Little,

Brown and Co., New York, NY.

Claims (1)

1. A TOBACCO SMOKE FILTERING ELEMENT COMPRISED OF A UNITARY ROD-LIKE BUNDLE OF AT LEAST 10,000 CONTINUOUS CELLULOSE ACETATE FILAMENTS, THE BUNDLE BEING APPROXIMATELY 8.1 MM. IN DIAMETER, THE FILAMENTS OF THE BUNDLE BEING LONGITUDINALLY ALIGNED AND COEXTENSIVE WITH THE LENGTH OF THE FILTER ELEMENT, AND THE FILAMENTS HAVING NONORIENTED SHORT PORTIONS THEREOF CRIMPED INTO DIVERGING AND CONVERGING RELATIONSHIP TO THE MAIN FILAMENT ALIGNMENT, THE SPACING OF THE ADJACENT ALIGNED CONTINUOUS FILAMENTS PROVIDING LONGITUDINAL PASSAGES FOR SMOKE THROUGH THE BUNDLE, THE FILTER ELEMENT BEING FURTHER CHARACTERIZED IN THAT THE AFORESAID FILAMENTS CARRY AND HAVE RELATIVELY UNIFORMLY DISTRIBUTED ON THE SURFACES OF THE FILAMENT 1-30% BY WEIGHT OF A WAX.

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