US2096795A - Manufacture of spun yarns from continuous filaments - Google Patents

Description

Oct. 26, 1937. H. DIREYFUS ,7

MANUFACTURE OF SPUN YARNS FROM CONTINUOUS FILAMENTS Filed NOV. 1, 1953 Patented Oct. 26, 1937 PATENT OFFICE MANUFACTlJRE OF SPUN YARNS FROM CONTINUOUS FILAMENTS Henry Dreyfus, London, England Application November 1, 1933, Serial No. 696,183' In Great Britain November 12, 1932 10 Claims.

This invention relates to the conversion of continuous filament yarns into yarns having the appearance of spun yarn, that is yarn made by spinning staple fibre.

In the manufacture of spun yarn from artificial fibres, 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 to produce a. staple of similar length to cotton fibres, or of 4, 7, 9, 12 inches or more to produce a staple somewhat similar in length to wool, and then subject the staple fibres produced. along or mixed with other natural or artificial fibres of suitable length to a series of operations appropriate to the length of the fibre, such operations being similar to those according to natural fibres such as cotton or wool; including opening, carding, drawing and spinning. These operations represent considerable expense in the production of such yarns, sincethey 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 by spinning staple fibres while avoiding the necessity for 1 forming continuous filaments into short lengths and subjecting the fibres thus produced to a spinning operation. In particular the purpose of the invention is to transform continuous filaments directly into spun yarn by breaking the filaments into staple lengths in the absence, however, of the considerable reduction in extensibility which ordinarily results from the stretching of filaments to breaking point.

Broadly, the invention contemplates rendering the filamentous material brittle in character, so that under the application of a stretching load breakage occurs with little or no extension of the filaments. Breaking thus taking place with little or no extension, the filaments are not subjected to internal strain which results in loss in extensibility, and the spun yarn produced from these filaments has thus sufiicient elasticity to enable it to be manipulated satisfactorily in textile operations.

The invention is particularly important in connection with the conversion of filaments of cellulose acetate or other cellulose derivatives, for example cellulose esters such as cellulose formate, propionate, and butyrate, and cellulose ethers such as ethyl, methyl and benzyl cellulose, but may be generally applied for the conversion of filaments into staple fibres. For example, in

operating on filaments of cellulose acetate -or other thermoplastic cellulose derivative, the temperature of the filaments may be so lowered that they become more rigid, and so capable of being broken with little extension. It is, however, advantageous to make use of the moisture or other liquid which textile materials are capable of absorbing to a greater or lesser degree, since the freezing or solidifying of included liquid has the effect of imparting brittleness even if the material of the-filaments has not reached that state. If necessary, the filaments may be specially conditioned before exposing them to the refrigerating medium in order to bring them into a statein which they can be easily broken without the use of very low temperatures. The invention enables breakage to be effected with the applicationof compara 'vely small load in machines of relatively light construction.

Quite low temperatures may be employed in carrying out the invention, e. g. down to 80 C. and for this purpose liquid gas, for example liquid air may be employed.

While liquid air has been mentioned as an exaple of suitable cooling medium, it will be understood that any other liquid or gaseous medium may be employed which is capable of bringing the filaments to the requisite low temperature. Thus, cooled brine may be used as a medium to bring the filaments to such a degree of brittleness as materially to reduce loss of extensibility on breakage. Good results are obtained with cellulose acetate filaments cooled to about 5 C.

In viewof the brittle nature of the filaments, it is desirable that the gripping devices themselves should not be such as to produce a rupture of the filaments merely by contact of the devices with the filaments. Pairs of rollers rotating at different speeds and spaced apart at a distance corresponding to the lengthof staple to be produced form convenient gripping means to exert'the desired breaking action on the filaments.

In order to avoid danger of further filament .breakage after the filaments have been transformed into staple fibres of the desired length by the gripping devices, means may be provided to restore the filaments rapidly to their original condition. For example, filaments rendered brittle by cooling as described above may be withdrawn from a cooled chamber in which they 3 are broken and given atmospheric temperature by contact with the air, or they may even be passed over heating means or Jets of hot air immediately after breakage. The broken filaments then form a coherent mass capable of being delivered to a twisting device which imparts twist and strength to the fibrous yarn. By twisting continuously with breaking uniformity of the fibre distribution is maintained, with consequent advantage to the quality of theproduct. A twisttube or like device may be employed to impart false twist to the material leaving the breaking device,.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 conveniently comprising'an endless band or pair of bands driven at an appropriate linear speed.

Any desired number of yarns may be converted into fibres in a single breaking apparatus. Several filamentous yarns may be led side by side to the apparatus and the fibres of these several threads may either be drawn together into a single sliver or may be maintained separate and separately twisted into a roving on leaving the apparatus. Thus, one such apparatus may serve a plurality of twisting spindles.

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 continuouspperation. If desired, a ring-spinning device may be used to impart the relatively high degree of twist in such final product. Two or more twisted yarns may be doubled together at any drawing stage to increase the evenness and strength of the final yarn.

Forms of apparatus suitable for carrying out the process according to the invention will now be described with reference to the accompanying drawing, in 'which:-

Fig. 1 shows in end elevation, filament cooling and breaking apparatus, 'certain frame elements being omitted for the sake of clarity.

Fig. 2 is a part sectional planview of the apparatus shown in Fig. 1, while Fig. 3 shows somewhat diagrammatically in end elevation another form of apparatus.

As shown in Figs. 1 and 2, continuous filamentary bundles 5.5, preferably in untwisted form,

unwinding from packages 6.6, are led through guides 1.1 and eventually to bobbins 8.8 of flyerspinning devices 9.9. After leaving the guides 1.1 the bundles pass through the nip of rolls III, II the roll II being disposed in such a manner that the bundles contact with a relatively large part of the periphery of the roll I 0, the extent of the arc of contact being indicated in dotted lines.

The lower roll I0 is hollow and is connected by a supply pipe I2 and an exhaust pipe I3 to a refrigerant supply, (not shown) from which refrigerant, e. g. brine, is passed through the roll as indicated by the arrows. Each pipe joint is maintained tight and comprises a nut I4 which screws on to a threaded hollow extension I5 of the roll axle and urges a vcircumferential lug I 6 of the pipe against a packing I! which is compressed against the extension I 5 and tends to expand outwardly against the inner wall of the nut II. The

roll III is thus free to rotate while the pipes I2.

and I3 are stationary, and no refrigerant is lost.

The upper'roll I I is maintained at low temperature by reason of its close proximity to the cooled 'lower roll III, and is supported in suitable bear- .ings in arms I8, to be described later. On passing between the cooled rolls, the bundles 5.5 are re- The fibrous nature of the ruptured bundles gen-.

erally maintains their continuity, but if desired, supporting means such as a travelling endless band or carriers may be arranged beneath the bundles between the rolls I9, 20 and 2|, 22. -The bundles 5.5 aredelivered from the rolls 2|, 22 in the form of untwisted fibrous sliver and proceed to the fiyer-spinning devices 9, over guides 23.23 where they are relatively lightly twisted and wound on the bobbins 8.8.

The cooling and breaking rolls may be of any desired length, necks being formed at suitable intervals to provide bearing surfaces for supporting means. Thus while four bundles only are shown in the figures, as many bundles as desired may be processed simultaneously merely byv lengthening the rolls in accordance with the number of bundles to be treated.

The upper rolls II, 20 and 22 are preferably quickly and simultaneously removable in order to allow of rapid forwarding by hand of new or broken bundles. This is effected conveniently by bearing the bosses ofall the upper rolls, viz. II,-

20, and 22, in the arms I 8'and pivoting the arms to the roll-supporting frame 24 at points 25.25. Thus, on lifting the arms I8, I8, the upper rolls are removed from contact with the lower rolls and leave room for bundle manipulation between the two sets. Conveniently, short lengths only of the upper rolls extend between successive pairs of arms I8; I8 so that on lifting the arms, the proc-. essing of the minimum possible-number of bundles is interrupted. Where such interruption is of frequent occurrence, it is advisable to mount sets of upper rolls singly, the lower rolls extending, of'course, along the whole length of themachine in'uninterrupted order.

If it is desired to impart to the bundles 5.5a greater degree of brittleness for a given low temperature, they may be passed over and in'contact with wicks 26.26 supplied with moisture from a trough or pipe 28 placed between the guides 1.1

and the roll I 0, so that the bundles are dampened before passing between the cooling rolls. The moisture thus applied to the bundles freezes on the filaments on contacting with the rolls I I), II

and enables them to .be more easily broken.

In order' to remove the frozen moisture so formed, and to restore the original temperature and pliability to the filaments after the breaking operation, hot air from a jet Z'I'may be directed at the bundles, or at each bundle, during the passage from the rolls 2|, 22 to the fiyer-spinning device. While each bundle is shown proceeding to a separate fiyer device, two or more bundles (now, of course, in the fibrous state) may be united and doubled together as a thick sliver or roving after leaving the rolls 2|, 22, and led to a common fiyer device, or, instead of leading the roving directly to a fiyer' device, the roving may be drafted to a finer count and then spun into thread.

- Alternatively or in addition to the above men-- through the space enclosed by the frame-work 24 immediately beneath the rollers, thus maintaining the whole apparatus at low temperature.

According to the apparatus shown in Fig. 3 the cooling means are not removed from the breaking means, the lower rear roll 30 of a breaking-roll set 30, 3| and 32, 33 itself serving to efiect the required cooling. The roll 30 is hollow and is supplied with refrigerant in a manner similar to that shown with reference to the roll ill of Figs. 1 and 2.

The bundles 34! after being cooled and ruptured into masses of fibres between the rolls 30, 3i and 32, 33 pass to drawing rolls 3t, 35 and 36, 31, maintained under pressure by a bridge 60 tightened by a nut 42 and bolt 4|, where the masses of fibres are drawn and reduced in cross section to a'sliver, the fineness of which depends on the rate of rotation of the rolls 36, 31 relative to the rolls 3d, 35. The drafted slivers so produced may be led singly through balloon guides 39 to a ring-spinning device 53 (one shown) where they are directly twisted into finished threads, or two or more slivers may be united and twisted together into thread by a single ring-spinning device. Drawing continuously with the breaking operation thus enables finished threads to be produced continuously in a single operation.

The moisture-applying device 26 of Fig. 1 may be incorporated in the apparatus of Fig. 3, and hot air blasts may be directed at the material after the breaking operation, so as to remove the im parted brittleness at least in part, and bring the fibres into substantially the same condition as the filaments before being subjected to the cooling operation.

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

1. Process for the production of staple fibre from continuous filaments, which comprises cooling the filaments to such a temperature as to render them temporarily brittle and While they are in a brittle condition breaking them into short lengths whereby the extensibility of the filaments is substantially preserved.

temporarily brittle, and subjecting the brittle filaments to a breaking load so as to break said fila ments at difierest points along their length and transform them into a continuous bundle of staple fibres whereby the extensibility of the filaments is substantially preserved.

3. In a process for the production of staple fibre yarns from continuous filaments, .the successive steps of moistening and cooling a plurality of continuous filaments so as to render them temporarily brittle, and subjecting the brittle filaments to a breaking load so as to break said filaments at difierent points along their length and transform them into a continuous bundle of staple fibres.

4. In a process for the production of staplefibre yarns from continuous filaments, the successive steps of applying moisture to a plurality of continuous filaments, cooling said moistened filaments so as to freeze said applied moisture and subjecting the filaments thus rendered brittle to a breaking load so as to break said filaments at different points along their length and transform them into a continuous bundle of staple fibre.

5. In a process for the production of staple fibre yarns from continuous filaments, the successive steps of rendering temporarily brittle a plurality of continuous filaments by cooling the same, subjectingthe brittle filaments to a breaking load so as to break said filaments at diiferent points along their length and transform them into a continuous bundle of staple fibres whereby the extensibility of the filaments is substantially preserved, and twisting and winding said bundle.

6. In 'a process for the production of staple fibre yarns from continuous filaments, the suc-' cessive steps of rendering temporarily brittle a bundle of continuous filaments by cooling the same, subjecting the brittle filaments toa breaking load so as to break said filaments at different points along their length and transform them into acontinuous bundle of staple fibres whereby the extensibility of the filaments is substantially preserved, drafting said bundle and spinning the drafted fibres into yarn.

7. In a process for the production of staple fibre yarns from continuous filaments, the successive steps of cooling a plurality of continuous filaments to such a temperature as to render them temporarily brittle, subjecting the brittle filaments to a breaking load'so as to break said filaments at different points along their length and transform them into a continuous bundle of staple fibres whereby the extensibility of the filaments is substantially preserved, and applying heat to said filaments torestore them to a nonbrittle condition.

8. In a process for the production of staple fibre yarns from continuous filaments, the successive steps of rendering temporarily brittle a plurality of continuous filaments ofcellulose acetate or other organic derivative of cellulose by cooling the same, and subjectingthe brittle filaments to a breaking load so as to break said filaments at different points along their length and transform them into a continuous bundle of staple fibres whereby the extensibility of the filaments is substantially preserved.

9. In a process for the production of staple fibre yarns from continuous filaments, the successive steps of bringing a plurality of continuous filaments of cellulose acetate to a temperature of about 5 C. so as to render the filaments temporarily brittle, and subjecting the brittle filaments to a breaking load so as to break said filaments at different points along their length and transform them into a. continuous bundle of staple fibres whereby the extensibility of the filaments is substantially preserved.

10. In a process for the production of staple fibre yarns from continuous filaments, the successive steps of rendering temporarily-brittle a plurality of continuous filaments by cooling the same, and subjecting the brittle filaments to a breaking load so as to break said filaments at different points along their length and transform them into a continuous bundle of staple fibres whereby the extensibility of the filaments is substantially preserved, and blowing heated gas on to the fibres to restore them to a non-brittle condition. V

HENRY DREYFUS.

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