US3253969A - Process for making cigarette filter rods from crimped continuous filaments - Google Patents

Description

May 31, 1966 J. K. PANNILL, JR., ETAL 3,253,969

PROCESS FOR MAKING CIGARETTE FILTER RODS FROM CRIMPED CONTINUOUS FILAMENTS Filed April 30. 1963 CR/MPED ao/vrm/uous FILAMENTS F/L TER [a 2 CIGARETTE F/L rER WRAP 5 PAPER roe/1000 WRAP roaAcco CRIMPED CON Tl/VUOUS F /L A MEN 7'5 (Smaller Angle of Retained Crimp a a/aARETrE m A m I F/L TER WRAP PAPER roaAoco WRAP TOE/I060 FIG. 2. e

r i I y .'l 3o F IG. 4.

WV JAMES F. CAI/V5.5

R/aHARo F. DYER FIG. .5. JAMES KNOX PA/VN/LL,JR.

INVENTOR.

BY FMM ATTORNEYS United States Patent PROCESS FOR MAKING CIGARETTE FILTER RODS FROM CRIMPED CONTINUOUS FILAMENTS James Knox Pannill, In, Richard F. Dyer, and James F. Caines, Kingsport, Tenn., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed Apr. 30, 1963, Ser. No. 276,965 3 Claims. (Cl. 156-166) This invention relates to tobacco smoke filter cigarettes. More particularly this invention relates to processes for making filter cigarettes containing a filter tip or element which is of lighter weight than currently used rods or tips but yet is as efficient or more efiicient than presently used products of the class indicated.

This application is a continuation-in-part of our earlier applications Serial No. 27,091, filed .May 5, 1960, now US. Patent No. 3,099,594, and Serial No. 81,593, filed January 9, 1961, now abandoned.

As is well known in the industry, a large number of small filter rods or elements are used in connection with tobacco products. For example, a large portion of the cigarettes produced domestically and abroad have filter tips which are usually at least one centimeter or more in length and of the diameter of the tobacco portion of the cigarette to which the tip is associated. While some of these filter tips or plugs are made from paper, cotton wadding or the like, a large number are made from crimped synthetic filaments. In any event, when it is considered published reports indicate that an excess of 60,000,000 pounds of filter material is consumed in filter manufacture domestically, it is readily apparent that reducing the weight of such filter tips is a highly desirable result, particularly if this may be done without impairing the filtering efiiciency of the tip. Such reduction in weight is not only useful in savingmaterial cost, but gives other benefits such as lowering shipping costs which, in View of the highly competitive nature of the filter market, is of value. In other words, because of the rather small cost margins involved due to filter rods being a low priced item, it is apparent that such savings which may be accomplished by the present invention represent a highly desirable result.

After extended investigation we have discovered a process for manufacturing filter cigarettes having filter rods or tips which are substantially lighter in weight than currently used filter rods but which rods are as eflicient or more efiicient as respects tar removal and in other respects are equal to or better than currently used filter rods.

One object of this invention is to provide a novel process for making a cigarette filter rod or tip from mechanically crimped synthetically spun filaments wherein the longitudinal contraction due to the crimps is retained to a substantially greater extent than is possible with prior art filter rod production methods. A further object is to provide a combination process of preparing the tip of lighter weight and associating it with the tobacco portion of the cigarette to form a filter cigarette. Another object is to provide a filter element for cigarette filter purposes which is lighter in weight than comparable filters in commercial use but which filter is equal to or better in etficiency than currently used filters. Still a further object is to provide a new filter tip cigarette comprised of the novel rod of the present invention in association with smoking tobacco. Another object is to provide a filter cigarette which has a filter which is substantially harder than currently used filters. Other objects will appear hereinafter.

In the broader aspects of our invention we have found that if the synthetically spun filaments which are to be made into tobacco smoke filter rods are subjected to a treatment which we refer to as cylindrical blooming, the resultant filter rods may be made with a definite weight advantage. This weight advantage is at least 3 percent and in many instances the weight advantage may be up to 15 percent or 20 percent. Such lighter weight filter rods of the present invention exhibit tar removal efficiency, pressure drop characteristics and the like as good or better than currently produced filter rods. In addition, the new rods of the present invention are firmer than prior art rods and, therefore, are more adaptable to assembly in automatic machinery as well as supplying a firmer tip which many smokers prefer.

In a filter rod, the contraction of the base-fiber due to retained crimp may be equated and is generally referred to as the average angle of retained crimp (a). If no crimp were retained, the fibers would lie essentially parallel to the smoke flow path through the filter and (a) would approach Since little fiber surface would then be oriented normal to the smoke flow path, filtration efficiency, which depends upon impingement, would be low.

Our new filter has an average angle of retained crimp substantially smaller, and consequently a greater area of fiber surface presented to the smoke, than has been possible in prior art rods made from filaments. Such reduction in the crimp angle is at least as great as 25 and usually is within the range of 2560. We have found that this reduction in the angle of retained crimp permits the weight saving aforesaid. Also other unexpected advantages may be obtained therefrom such as increased firmness and the like. This may be accomplished by subjecting the crimped synthetically spun filaments to a treatment of cylindrical blooming which will be described in detail hereinafter.

For assistance in a further understanding of our invention, reference is made to the attached drawing forming a part of the present application.

FIG. 1 is a side elevation view on a slightly enlarged scale and partly in section for showing aprior art filter.

FIG. 2 is likewise a side elevation view partly in section for illustrating the filter of the present invention wherein the contraction due to retained crimp is appreciably greater.

FIG. 3 is a diagrammatic side elevation view on a considerably enlarged scale of a crimped filament for illus- Y trating the matter of angles as referred to above and as will be described in more detail hereinafter.

FIGS. 4 and 5 are also similar side elevation views on an exaggerated scale of a plurality of filaments for further illustrating the matter of crimp retention.

Referring to FIGURE 1 which concerns the prior art glter, 2 indicates the over-all cigarette to which the filter tip 3 is attached. This filter tip or plug is wrapped with a usual filter wrap material such as paper as indicated at 4-. The filter is made up of several thousand crimped continuous filaments generally indicated as at 5. However, it will be noted as at 6 that although the contraction due to crimp may be discernible, such is not to the comparable extent as is the ease in the present invention as will be discussed in connection with FIG- URE 2.

Referrinng to FIGURE 2, in a comparable manner a cigarette is indicated at 8. The filter wrap 9 may be the same as in FIGURE 1. However, the filter 10 of the present invention, although it may be made of the same size and composition of crimped continuous filaments, the structure and arrangement of the filaments is different from that of FIGURE 1. For example, re-

ferring to a group of filaments at 11 it Will be observed that the contraction due to retained crimp angle is very great. That is, in the present-invention it is preferred that the average angle of retained crimp be at most 100.

Referring now to FIG. 3 the following formula may be derived:

a angle of retained crimp Y=length of equivalent to Wt. of crimp-free tow 2X=length equivalent to wt. of fiber contracted due to retained crimp For a rod L mm. long L=length of rod, mm. T: total denier of the uncrimped tow 9 X l =mm./gm./denier W=dry wt. rod, gms.

the 140 indicated in FIG. 4, the resultant filter will not be as good as that of FIG. 5 where the angle is indicated as 90.

Further information concerning the method of manufacture and the new structure of the filter rod of the present invention will be had from the following description. A tow of a suitable nature for making filters would be obtained. This tow may be a tow such as currently used in filter manufacture, but will have a total denier 30 to 50 percent lower than would be selected to produce an equivalent filter by prior art processes. Or, the tow may be of certain types to be described below such as debundlized tow.

Quite useful tows are described in Crawford and Stevents U.S. Patents 2,794,239, 2,953,837 and 2,953,838.

Such tows althouugh of a compacted nature have useful yarn treating agents thereon and are preferably uniformly crimped 'to start with. While for a number of reasons we prefer a tow essentially comprised of crimped continuous cellulose acetate filaments, it is possible in the present invention to utilize filaments of other compositions such as regenerated cellulose, polyesters, polyamides, polyacrylics, and polyolefins and the like, as will be apparent from the description which follows and certain of the specific examples.

Another form of tow which may be used in the present invention is debundlized tow as described in companion Caines, Dyer and Pannill application Serial No. 81,222, now U.S. Patent No. 3,126,095. In the event debundlized tow is employed, such tow may be substantially directly fed intothe garniture of the filter rod.

forming mechanism as shown in Crawford and Stevens Patent 2,794,480 or as disclosed in Wexler companion Patent 3,016,945.

On the other hand, if the tows of the aforementioned Crawford and Stevens patents are used or other commercial tows of somewhat the same general type, such tow is subjected to cylindrical blooming generally in accordance with the disclosure of Caines, Dyer and Pannill parent application Serial No. 27,091 (now U.S. Patent No. 3.099594); In further detail, the suitable cylindrical blooming for processing the tow to make the 7 new filter rods of the present invention, the preferred gas pressure to utilize and the like information is generally in accordance with the following: v

The tow is withdrawn from the package vertically through a banding device such as shown in Stevens Patent 2,908,045 and thence over a guide to the nip between a pair of feed rolls. The banded tow is passed then over a suitable plasticizer applicator, if a plasticizer is desired, and thence to the cylindrical blooming jet. In the jet the tow passes through a cylindrical entrance noz zle inch in diameter whence it emerges in the path of a peripheral stream of high velocity air. The preferred air pressure used is 20-25 pounds per square inch, gage. The filaments of the tow are thoroughly debundlized in the throat of the cylindrical jet and in the subsequent divergent passage of the jet with a minimum of longitudinal extension. At the exit of the jet the debundlized tow is compacted in a chamber consisting of spring steel strips or other restricting means wherein a certain amount of crimp compaction is restored and a controlled withdrawal rate is assured.

By the procedure just described, the contraction due to retained crimp is maintained at a much higher level than is possible with tension (mechanical blooming). Furthermore, even with tow having a high degree of crimp such cylindrical blooming does not cause breakage or other damage to the tow whereas prior art mechanical treatments are limited to some extent by the possibility of potential damage to the crimp or because of undue breaking.

After the tow has been cylindrically bloomed in a suitable manner, it is then withdrawn by means of a suitable roll and passes thence to a filter rod forming machineof the type generally used in the commercial production of filters and cigarettes. The tow is here wrapped in a suitable wrapper at a specified diameter and, after sealing, is cut into lengths suitable for use for assembly onto cigarettes.

A further understanding of our invention will be had from the consideration of the following examples which are set forth for illustrating certain improved embodiments.

Example I Rods were produced by the tension blooming process as disclosed in U.S. Patent 2,794,480 (Crawford et al.) from 3 D/F, 84,600 T.D. cellulose acetate tow. Using the cylindrical blooming process of the present invention,

it was found that a 3 D/F, 53,000 T.D. resulted in rods of approximately the same pressure drop. Analyses of the rods is tabulated below.

Although there was considerable reduction in weight, the new filter of the present invention functioned as well as the older filter in all respects and in certain respects had better properties.

Example II As above, filter rods were made by the two processes, using 5 D/F cellulose acetate tows. The data are tabulated below.

Tension Cylindrical Process Process Tow -100, 000 5-50, 000 Crimp per inch 12 Rod pressure drop, in. of water 11.0 11. 4 Hardness value 5. 2 3. 2 Wt. of acetate tow in red, grns.-. 1.015 .787 Reduction in tow weight, Perce 22. 5 Angle of retained crimp, degrees 160 80 Example III As in Example I, filter rods were made by the two In the above examples, all rods were 24.8 mm. circumference by 90 mm. long. The hardness value is the rod compression under a specified load, measured in tenths of a millimeter. A low value is indicative of a firm rod. The tars removal was determined for a mm. filter tip, using standard cigarettes and an automatic smoking machine.

Example IV Rods were produced by the cylindrical blooming process without plasticizer using 3 -D/F 80,000 T.D. viscose tow. Rod firmness was sufiicient for assembly although no filament bonding agent was used. The pressure drop and weight were comparable to those obtained with equivalent cellulose acetate tow.

Example V Filter rods produced from a 3.4 D/F, 50,000 T.D. polypropylene tow by the cylindrical blooming process had an average angle of retained crimp of 68. Tow debundlizing was satisfactory and the rod characteristics were somewhat comparable of those of conventional cellulose acetate rods although no plasticizer was used.

Example VI Filter rods were produced with the cylindrical blooming process using a highly randomized tow produced by the free-fall spinning method at very low spinning draft, in the order of 0.2, with a 4 D/F tow of 33,000 T .D. which had an apparent total denier of 50,000 due to the random orientation of the filaments, filter rods of commercial firmness were produced by applying the plasticizer with a wick applicator to the outer surfaces of the tow and redistributing the plasticizer throughout the tow uniformly enough to provide the necessary bonding at filament intersections by passing the tow through the cy- 6 lindrical blooming jet described in parent Caines et al. application referred to above.

It can be seen from the above examples that by the present invention it is possible to produce a filter rod which is considerably lighter in weight than prior art rods but which is eflicient and in some respects more advantageous than the prior art rods. It can also be seen that filters may be produced from materials which cannot be plasticized, in the accepted sense of the term, but which have sufficient firmness for further processing.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be eifected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A process for converting a bundle of crimped continuous filaments of a total denier of less than 80,000 into a filter rod product of lighter weight than heretofore conventionally manufactured rods, which product is attached to a cylinder of shredded tobacco enclosed in a wrapper.

whereby a filter tipped cigarette is formed which comprises the following steps of obtaining said bundle of crimped filaments with a crimp of at least 7 crimps per inch and an angle of crimp below passing said crimped filaments into and through a jet supplied with high velocity gas, which gas acts upon the filaments, retarding the exit of the filaments from the jet immediately adjacent the exit from the jet, whereby the crimped filaments are separated one from another so as to enlarge the cross-sectional area occupied by the filament bundle and the bundle is debundlized without permanently elongating the filaments therein, reducing the cross-sectional area occupied by the debundlized filaments while maintaining said angle of crimp in the filaments below 100", enclosing the compressed reduced cross-sectional area bundle of filaments in a wrapper, and severing the wrapped bundle into lengths suitable for use in machines which attach said lengths as filter tips to said tobacco.

2. The process as defined in claim 1 which includes the step of applying a liquid treating agent to the filaments of the bundle prior to supplying the bundle to the jet.

3. The process in accordance with claim 1 wherein the crimped filaments are principally of cellulose acetate of a denier of less than 8 and of an initial crimp greater than 9 crimps per inch and a resultant rod product is of a weight of the order of not substantially more than .7 gram.

References Cited by the Examiner UNITED STATES PATENTS 2,805,671 9/1957 Hackney et al. I 131208 2,900,988 8/1959 Crawford et a1 131-208 3,099,594 7/1963 Caines et al. 156-180 EARL M. BERGERT, Primary Examiner.

MELVIN D. REIN, Examiner.

Claims (2)

1. A PROCESS FOR CONVERTING A BUNDLE OF CRIMPED CONTINUOUS FILAMENTS OF A TOTAL DENIER OF LESS THAN 80,000 INTO A FILTER ROD PRODUCT OF LIGHTER WEIGHT THAN HERETOFORE CONVENTIONALLY MANUFACTURED RODS, WHICH PRODUCT IS ATTACHED TO A CYLINDER OF SHREDDED TOBACCO ENCLOSED IN A WRAPPER WHEREBY A FILTER TIPPED CIGARETTE IS FORMED WHICH COMPRISES THE FOLLOWING STEPS OF OBTAINING SAID BUNDLE OF CRIMPED FILAMENTS WITH A CRIMP OF AT LEAST 7 CRIMPS PER INCH AND AN ANGLE OF CRIMP BELOW 100*, PASSING SAID CRIMPED FILAMENTS INTO AND THROUGH A JET SUPPLIED WITH HIGH VELOCITY GAS, WHICH GAS ACTS UPON THE FILAMENTS, RETARDING THE EXIT OF THE FILAMENTS FROM THE JET IMMEDIATELY ADJACENT THE EXIT FROM THE JET, WHEREBY THE CRIMPED FILAMENTS ARE SEPARATED ONE FROM ANOTHER SO AS TO ENLARGE THE CROSS-SECTIONAL AREA OCCUPIED BY THE FILAMENT BUNDLE AND THE BUNDLE IS DEBUNDLIZED WITHOUT PERMANENTYL ELONGATING THE FILAMENTS THEREIN, REDUCING THE CROSS-SECTIONAL AREA OCCUIPED BY THE DEBUNDLIZED FILAMENTS WHILE MAINTAINING SAID ANGLE OF CRIMP IN THE FILAMENTS BELOW 100*, ENCLOSING THE COMPRESSED REDUCED CORSS-SECTIONAL AREA BUNDLE OF FILAMENTS IN A WRAPPER, AND SERVING THE WRAPPED BUNDLE INTO LENGTHS SUITABLE FOR USE IN MACHINES WHICH ATTACH SAID LENGTHS AS FILTER TIPS TO SAID TOBACCO.

2. THE PROCESS AS DEFINED IN CLAIM 1 WHICH INCLUDES THE STEP OF APPLYING A LIQUID TREATING AGENT TO THE FILAMENTS OF THE BUNDLE PRIOR TO SUPPLYING THE BUNDLE TO THE JET.

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