US2003400A - Manufacture of staple fiber yarns - Google Patents

Description

June 4, 1935. w. l. TAYLOR ET AL MANUFACTURE OF STAPLE FIBER YARNS Filed June 23, 1953 ATTORNEYS from staple fiber.

Patented June 4,"

PATENT OFFICE MANUFACTURE OF STAPLE FIBER YARNS William Ivan mm and Leslie Brisbane Gibbins, Spon'don; near Derby, England, aesigm' ore to Celanese Corporation of America, a corporation of Delaware Application 15 Claims.

Thisinvention relates to the manufacture of textile materials, and in particular to yarns having a basis of continuous filaments, buthaving the appearance of spun yarn, that is yarn made In the manufacture of spun yarn from artificial fibers, the usual practice is to cut continuous artificial filaments or waste filaments into comparatively short lengths, for example of 1 to 2 inches or more, and then subject the staple fibers produced to a series ofoperations appropriate to' the length of the fiber, such operations being similar to those accorded to natural fibers such as cotton or wool, including opening, carding, drawing and spinning. These operations represent considerable expense in the production of such yarns, since they involve a relatively slow transformation of the initial fibrous material to a finished yarn.

The object of the present invention is to produce yarn having an appearance similar to that of yarn made from spun fiber while avoiding the necessity for forming continuous filaments into 'short lengths and spinning the fibers thus produced. The particular p rpose of the invention is to enable a fairly close measure 'of' control to be obtained over the length of the fiber, so as to obtain aspun yarn as uniform as possible in structure," and consequently of. a fairly high degree of strength. In its broadest aspect the invention comprises the conversion into fibrous yarns of continuous filament yarns the strength of whose filaments is so modified that under the application of a breaking load, the filaments are broken or torn at fairly definite points. The fibrous mass thus produced is then twisted to bind the fibers together into a yarn similar to spun yarn. The points of breakage should be at such distances apart along the length of the filaments, and so spaced apart between filament and filament along the length of the yarn, that the fibers produced by breakage of the several filaments overlap each other in the yarn.v 'I'his spacing of the points of breakage should be as even as possible, so that not only are fibers of substantially-equal length produced, but also that substantially constant overlap is obtained. Thus, for example, in a continuous filament yarn containing 40 filaments a spacing of the points of breakage between filament and filament of approximately a twentieth of an inch would enable fibers of approximately two inches in length to overlap evenly and constantly throughout the length of the fibrous yam produced.

The invention is applicable to the production June 23, 1933, Serial No. 677,218 Great Britain Jilly 4, 1932 of fibrous yarns from all kinds of continuous or substantially continuous filaments or mixtures, of continuous filaments. Among artificial contin-. uous filament yarns which may be converted according to the invention may be mentioned cellulose acetate-or other organic derivatives of cellulose,'such as other cellulose esters, e. g., cellulose formate, propionate and butyrate, and'cellulose ethers such as ethyl and benzyl cellulose, and viscose, nitro-cellulose, and cuprammonium 1o yam. e

The modification of the filament structure to bring about the fairly definite position of filament breakage may be ,efiected in various ways, con-' veniently by weakening the material of the'fila- 15 ments at inervals. If the filaments are rendered sufiiciently weak, breakage may be effected without unduly extending the filaments as a whole, the extension taking place mainly at the weakened portions, so that the elasticity of the final 2o fibers may not be seriously reduced by the application of the breaking load. The material of the filaments may be weakened at intervals, for example, by bruising the filaments mechanically, or by applying a liquid to the filaments having a-solvent or softening or like weakening efifectu Instead of weakening the filaments at intervals they may be treated with a size, except at the intervals at which they are desired to break, the intermittent coating of size serving to reinforce the filaments over the greater part of their length.

After the strength of the filaments has been modified, they are converted into staple lengths by passing them successively through two pairs of nipping rollers of which the second pair rotates faster than'the first, so 'as to draw out and break the filaments at the weak points. A twist tube or like device may be employed to impart false twist to the material leaving'the breaking device, 40

so as to give it sufiicient strength to maintain itself until a definite degree has been imparted by the fiyer of the twisting spindle. If required supporting means may be provided between the .rollers of the breaking device, such means con- 45 veniently comprising an endless band or pair of bands driven at an appropriate linear speed,

Any desired number of yarns may be converted into fibers in a single breaking apparatus. Several filamentous yarns may be led side by side to the apparatus and the fibers of these several threads may either be drawn together into a single sliver ormay be maintained separate and separately twisted into a roving on leaving the little or no staggering of the weakened places is found. In this case, a number of such yarns or bundles is assembled together, either before, durmg, or after breakag so that the fibers produced from the several yarns or bundles are evenly distributed in the sliver. The slivers thus produced are twisted into rovings, and such rovings, or large rovings produced from large filament bundles with distributed points of weakness may be subjected to drawing and further twisting until yarns are produced having the requisite degree of fineness and strength. After breakage, the fibrous bundle may be passed directly through draw rollers to reduce the size of the bundle, in which case the final yarn may be produced in the one continuous operation. Two or more twisted yarns may be doubled together at any drawing stage to increase the evenness and strength of thefinal yarn.

In order to improve the spinning properties of the fibers, which have the smoothness of the filaments from which they are produced, roughening media ,may be applied to increase the adhesion between the fibers. In'view of the importance of maintaining the even arrangement of the fibers in the sliver-like mass produced by breaking the filaments, it is desirable that any such media should be applied to the filaments before breaking. Such media may be of an insoluble type, e. g. kieselguhr, talc, pumice, carborundum, and emery, and may be applied dry or as pastes or suspensions at any suitable stage prior to breaking, e. g. continuously with the production of artificial filaments. Soluble materials in crystalline or powder form may also be applied dry. Soluble media may also be used, conveniently being applied as solutions of high concentration, as described in U. S. application S. No. 585,381 filed 7th January, 1932, so that drying can be economically effected to leave the desired amount of roughening media on the fibers.

Where the materials are subject to electrification, as for example in the case of cellulose acetate or other organic derivatives of cellulose, hygroscopic materials may be applied to the materials. For example, hygroscopic bodies may be applied as described in U. S. application S. No. 614,853 filed 1st June, 1932, the filaments preferably being dried before breaking.

By way of example some methods of carrying out the invention will now be described in greater detail with reference to the accompanying drawing in which:--

Figure 1 is a perspective view of a form of apparatus for bruising the filaments at intervals in order to facilitate their breakage;

Figure 2 is a perspective view of a form of breaking apparatus which may be employed for converting the bruised filaments into fibers;

Figure 3 is another form of apparatus for bruising the filaments;

Figure 4 shows a further form of apparatus for weakening the filaments at intervals; and

Figure 5 shows a form of apparatus for modifying the strength of the filaments without weakening them.

Referring to Figure 1, a number of threads 5 each consisting of a number of continuous filaments, are drawn over the ends of bobbins 6 and over a guide bar I and are passed between a pair of rollers 8, 9. The bobbins 6 are sufiiciently large to enable the apparatus to continue in operation for long periods without interruption. The lower roller 8 is driven by means of a pulley l and belt II. The upper roller 9. is driven by its engagement with the roller 8. The roller 9 is provided with teeth l2 helically disposed on the cylindrical surface thereof, and the roller 8 is provided with recesses l3 adapted to engage with the teeth l2. The roller 9 is pressed downwardly on the roller 8 by means of a stirrup l and screw l6, so that pressure between the rollers may be adjustable. At the same time a braking device .11 is provided, acting on the upper roller 9 in order to cause the faces of the teeth I2 to coact with the sides of the recesses I3.

The threads of filaments 5 are spread out by a comb 48 so as to be engaged by different teeth l2 and recesses l3, and in passing between the rollers 8, 9 the filaments of the threads 5 are bruised at intervals corresponding to the circumference of the rollers 9, 9 and the number of helices of teeth or of recesses provided thereon. The bruised portions of the threads 5 are indicated at l9, and it will be seen that the positions of the bruises are staggered as between the different threads. The threads 5 after passing through guides 28 on a polished metal guide plate 2| are collected together by a further guide 22 and are subsequently led by means of a traverse guide 23 on to a rotating bobbin 24 by means of which they are collected.

In Figure 2, means are illustrated for effecting the breakage of the filaments into fibrous lengths. The thread of bruised filaments 25 may either be drawn from a bobbin such as the bobbin 24 in Figure 1, or may be drawn directly from the guide 2| of the apparatus illustrated in Figure 1. The latter method, when it is possible, avoids the inconvenience of storing the bobbins 24, reducing the possibility of undesired breakage of the filaments in transport or storage. The thread 25 is conducted successively between two pairs of rollers 26, 21 which are preferably smooth surfaced, and covered with rubber, so as to nip the thread. The distance between the rollers 26, 21'slightly exceeds the interval between successive points of bruising on the filaments 25. The rollers 21 are driven at a higher peripheral speed than the rollers 26 so that the filaments are stretched between the rollers, and, as a result of their previous weakening, readily break at the points where such weakening has been efiected. Since weakening has been effected at regular intervals along the filaments of the thread 25, the filaments are broken into staple lengths of substantially uniform size. At the same time since the different filaments of the thread 25 have been weakened at different points, the thread 25 is not broken as a whole, and issues as a uniform and continuous thread 28 of staple fibers ready to be collected on a flier spinning apparatus 29 where it is twisted and wound on to a bobbin 30. The twist inserted by the flier 29 into the continuous thread 28 gives it suflicient cohesion to stand up to any subsequent spinning operation to which it may be subjected.

In Figure 3 a pair of rollers 32, 33 is illustrated which may be used in place of the rollers 8, 9 shown in Figure l. The roller 33 is provided with one ormore upstanding helical ridges 34 engaging with a number of helical grooves 35 in the rollers 32. The ridges 34 and the groove 35 co-operate to bruise the filaments of the threads 5 at intervals, in a manner similar to that described with reference to Figure 1. Instead of arranging the filaments as a number of threads of filaments as in Figure 1, the filaments are evenly spread out into a sheet 31, by means of a reed 38, so that the points of bruising are more evenly distributed throughout the whole bundle of bruised filaments.

In Figure 4, a number of filaments in the form of a fiat sheet 31, is caused to pass from a reed 38 under a cranked portion 39 of a rotating shaft 40. The filaments then pass over a wick 4|, dipping into a vessel 42 containing a liquid adapted to soften or weaken the substance of the filaments. The wick 4| is disposed obliquely across the sheet of filaments 31, so that the points of weakening of the different filaments are differently disposed along the length of the sheet 31. The level of the wick 4| and the level of the shaft 40 are so arranged that the time during which the filaments are pressed down into contact with the wick is short, so that the filaments are only weakened over a relatively small part of their length. The sheet of filaments 31 may either be collected on a bobbin, as described with reference to Figure l, or may be conducted directly to breaking rollers, as described with reference to Figure 2.

The liquid applied by the wick 4| may be a solvent or softening agent, or in the case of cellulose ester filaments, it may be a saponifying agent. As examples of suitable solvent or softening materials for use in connection with filaments of cellulose acetate, acetone, a mixture of acetone and thiocyanate, acetic acid, lactic acid, formic acid, 1.4-oxanone, tetrachlorethane, chloroform, ethyl acetate, phenol, or aniline may be used, preferably at a strength which merely brings about weakening of the filaments without rendering them unduly soft and liable to stick to each other. Thus, for example, a dilute solution of acetone and water may be employed. Water may also be employed as a weakening agent, thus utilizing the reduction in tenacity found in wetting artificial filaments as a means for securing breakage at predetermined points.

Instead of a solvent or softening liquid, a saponifying agent may be employed in connection with cellulose ester filaments, in the manner described for example in U. S. application S. No. 415,803 filed 21st December, 1929. Such saponification may be complete, or may result only in such partial conversion of the cellulose ester that the loss in volume brings about a sufiicient weakening of the filaments to ensure their breakage at the parts saponified. Where saponification has taken place, the filaments are capable of receiving differential colour effects, so that the ends of the fibers may be coloured differently from the body of the fibers, thus enabling a mixed colour effect to be obtained in the spun yarn. Where, however, the saponification is only partial, level dyeing may be effected, since the partially saponified cellulose ester retains its affinity for the usual dyestuffs.

The apparatus shown in Figure 4 may be employed with slight modification for the application of a size, to strengthen the filaments except over short lengths occurring at regular and frequent intervals. A better form of apparatus for the purpose however is illustrated in Figure 5. In this figure, a sheet of filaments 31 proceeding from a reed 38 pass over and in contact with a drum or roller 45, which dips into a trough 46 containing the size' to be applied. Deep helical grooves 41 in the surface of the roller 45 prevent the application of size at points occurring at intervals along the filaments, and owing to the helical nature of the grooves 41, the points of non-application are differently disposed on the different filaments of the sheet 31. By the provision of a helical ridge instead of a helical groove, the apparatus may be employed for the application of a solvent or a saponifying agent.

Where a size or a saponifying agent is applied, so that some time is needed, either for drying of the size, or for the working of the saponifying agent, it is preferred to collect the filaments on a bobbin and to break them in a separate step.

Where a volatile and rapidly acting solvent material is applied however, it is preferred to conduct the filaments directly to the breaking apparatus before the solvent material has time to evaporate from the filaments, so that the full effect of the weakening can be utilized.

What we claim and desire to secure by Letters Patent is:-

1. Process for the production of spun yarns from continuous filaments, said process comprising modifying the strength of a plurality of associated continuous filaments at intervals, different filaments being so treated at diiferent points along their length, applying tension continuously along a bundle of such filaments until they break at intervals corresponding to the spacing of the modified portions, so transforming the filaments into a continuous bundle of staple fibers, and spinning the staple fibers so produced into a spun yarn.

2. Process for the production of spun yarns from continuous filaments, which comprises weakening a plurality of associated continuous filaments at intervals, different filaments being weakened at different points along their length, applying tension continuously along a bundle of such filaments until they break at intervals corresponding to the spacing of the weakened portions, so transforming the filaments into a continuous bundle of staple fibers, and spinning the staple fibers so produced into a spun yarn.

3. Process for the production of spun yarns from continuous elements, which comprises bruising a plurality of associated continuous filaments at intervals, different filaments being bruised at different points along their length, applying tension continuously along a bundle of such filaments until they break at intervals corresponding to the spacing of the bruised portions, so transforming the filaments into a con tinuous bundle of staple fibers, and spinning the staple fibers so produced into a spun yarn.

4. Process for the production of spun yarns from continuous filaments, which comprises applying a softening agent to a plurality of associated continuous filaments at intervals, different filaments being softened at difierent points along their length, applying tension continuously along a bundle of such filaments until they break at intervals corresponding to the spacing of the softened portions so transforming the filaments into a continuous bundle of staple fibers, and spinning the staple fibers so produced into a spun yarn.

.5. Process for the production of spun yarns from continuous cellulose derivative filaments, which comprises modifying the strength of a plurality of associated continuous cellulose derivative filaments at intervals, different filaments being so treated at different points along their length, applying tension continuously along a bundle of such filaments until they break at intervals corresponding to the spacing of the modified portions, so transforming the filaments into a continuous bundle of staple fibers; and spinning the staple fibers so produced into a spun yarn.

6. Process for the production of spun yarns from continuous cellulose acetate filaments, which comprises modifying the strength of a plurality of associated continuous cellulose acetate filaments at intervals, different filaments being so treated at different points along their length, applying tension continuously along a bundle of such filaments until they break at intervals corresponding to the spacing of the modified portions, so transforming the filaments into a continuous bundle of staple fibers, and spinning the staple fibers so produced into a spun yarn.

7. Process for the production of spun yarns from continuous cellulose ester filaments, which comprises applying a saponifying agent to a plurality of associated continuous cellulose ester filaments at intervals along their length so as to weaken them, different filaments being so'weakened at different points along their length, applying tension continuously along a bundle of such filaments until they break at intervals corresponding to the spacing of the weakened portions, so transforming the filaments into a continuous bundle of staple fibers, and spinning the staple fibers so produced into a spun yarn.

8. Process for the production of spun yarns from continuous filaments, which comprises weakening a plurality of associated continuous filaments at intervals, different filaments being weakened at different points along their length, applying tension continuously with such weakening along a bundle of such filaments until they break at intervals corresponding to the spacing of the weakened portions, so transforming the filaments into a continuous bundle of staple fibers, and spinning the staple fibers so produced into a spun yarn.

9. Process for the production of spun yarns from continuous filaments, said process comprising modifying the strength of a plurality of associated continuous filaments at intervals, different filaments being so treated at different points along their length, applying tension continuously along a bundle of such filaments until they break at intervals corresponding to the spacing of the modified portions, so transforming the filaments into a" continuous bundle of staple fibers, twisting such bundle of staple fibers into a sliver continuously with such breaking, and spinning the twisted product into a spun yarn.

10. Process for the production of spun yarns from continuous filaments, said process comprising weakening a plurality of associated continuous filaments at intervals, different filaments being so treated at different points along their length, applying tension continuously with such weakening along a bundle of such filaments until they break at intervals corresponding to the spacing of the weakened portions, so transforming the filaments into a continuous bundle of staple fibers, twisting such bundle of staple fibers into a sliver continuously with such breaking, and spinning the twisted product into a spun yarn.

11. Apparatus for facilitating the breaking of continuous filaments into substantially uniform staple lengths, said apparatus comprising means for distributing a plurality of travelling continuous filaments in the form of a sheet, and means for modifying the strength of the travelling filaments at intervals along their length, said means being adapted to effect such modification at points on different, filaments which are differently distributed along the length of said sheet.

12. Apparatus for facilitating the breaking of continuous filaments into substantially uniform staple lengths, said apparatus comprising means for distributing a plurality of travelling continuous filaments in the form of a sheet of individual filaments, and means for modifying the strength of the travelling filaments at intervals along their length, said means being adapted to effect such modification at points -on different filaments which are obliquely distributed across said sheet.

13. Apparatus for facilitating the breaking of continuous filaments into substantially uniform staple lengths, said apparatus comprising means for distributing a plurality of travelling continuous filaments in the form of a sheet, and means for bruising the travelling filaments at intervals along their length, said means being adapted to effect such bruising at points on different filaments which are differently distributed along the length of said sheet.

14. Apparatus for facilitating the breaking of continuous filaments into substantially uniform staple lengths, said apparatus comprising means for distributing a plurality of travelling continu- Ous filaments in the form of a sheet of individual filaments, a pair of rollers between which said sheet is caused to pass, and inter-engaging helical grooves and ridges disposed on said rollers, adapted to bruise the travelling filaments at intervals along their length, said rollers being adapted to effect such bruising at points on the different filaments which are obliquely distributed across said sheet.

15. Apparatus for facilitating the breaking of continuous filaments into substantially uniform staple lengths, said apparatus comprising means for distributing a'plurality of travelling continuous filaments in the form of a sheet of groups of filaments, a pair of rollers between which said sheet is caused to pass and inter-engaging teeth and recesses helically disposed on said rollers adapted to bruise the travelling filaments at intervals along their length, said rollers being thereby adapted to effect such bruising at points on different filaments which are differently distributed along the length of said sheet.

WILLIAM IVAN TAYLOR. LESLIE BRISBANE GIBBINS.

Images