AU606154B2

AU606154B2 - Yarn, in particular sewing yarn, and process and device for manufacture thereof

Info

Publication number: AU606154B2
Application number: AU16215/88A
Authority: AU
Inventors: Karl-Heinz Butzheinen
Original assignee: ACKERMANN GOEGGINGEN AG
Current assignee: ACKERMANN-GOGGINGEN AG
Priority date: 1987-05-27
Filing date: 1988-03-30
Publication date: 1991-01-31
Anticipated expiration: 2008-03-30
Also published as: ATE82023T1; DE3875734D1; CA1330411C; NO171283C; AU1621588A; FI85291C; FI895600A0; KR890701813A; DK588989A; EP0362214B1; WO1988009403A1; DK166691B1; NO171283B; DE3717921A1; NO890177D0; EP0362214A1; DK588989D0; FI85291B; DE3717921C2; NO890177L

Abstract

In the case of yarns consisting of at least two basic yarns bounded together by a hot-melt adhesive yarn, it is difficult to achieve satisfactory bonding while maintaining the required yarn properties. In particular, this type of yarn requires very strong twisting. To overcome these drawbacks, it is proposed that the basic yarns consisting of multiple thread filament yarns are swirled with at least one multiple thread adhesive yarn, so that as a result of the formation of loops and curves along the yarn cross-section during swirling, strong bonding is obtained together with other excellent yarn properties.

Description

oi ine application.

Insert place and date of signature.

Signature of declarant(s) (no asitestation required) Note! Initial all alterations.

COMMON WEALTH OF AUSTRALIA PATEENTS ACT 1952 COMPU7,TE SECIFICATO NAME ADDRESS OF APPLICANT: Ackermanm-Goggingen AG Fabrikpzrasse I11 Augsburg D-8900 Federal Republic of Germany NAME(S) OF DNVENTOR(S): Karl-Heinz BUTZHEINEN 4-k A ADDRESS FOR SERVICE: DAVIES COLLISON Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: Yarn, in particular sewing yarn, and process and device for manufacture thereof Tho following statement is a full description of this invention, including the best method of performing it known to me/us:- YARN, IN PARTI1CULAR SEWING YARN, AND PROCESS AND DEVICE FOR MANUFACTURE THEREOYF This invention relates, to a method for producing a sewing yarn, an apparatus for carrying out the method and a sewing yarn made by the method.

sees* Ina reviously proposed method for producing sewing yarn (US-A-3,251,181), a 15 single multifilament filament thread or, alternatively, two or more multifilament filament threads are subjected jointly to airstream texturing so that in the former case the individual filaments of the single filament thread are swirled together and in the latter case the individual filaments of the various filament threads are 0o swirled together. Heat treatment of the resulting bulky thread composite takes 20 place simultaneously with the airstream texturhig in that the fluid used for the airstream texturing is supplied at elevated temperature. All the filament threads consist of a melt-bonding material, the elevated temperature of the fluid 4~*employed for the airstream texturing being chosen so that the individual filaments of the filament threads just start to melt, without melting completely, and thereby -bo nd together in th- bulky, state produced by the airstream texturing, As a result, a bulk yarn held together by bonding is obtained but because of its bulkiness cannot be used as sewing thread, Also, the strength of the bonding of the thread composite will no doubt be relatively small because the bonding effect of the multifilament bonding filament thread or threads is initiated during the airstream texturing operation in which the individual filaments of the filament threads are relatively loosely interlaced.

.9Wb3o,WPvr.DSK2,1621SSpc,1 -2- It has also been previously proposed (EP-A-0 057 583) to swirl together two or more multifilament filament threads by airstrearr texturing and thereafter subject respective fixed lengths of the swirled thread composite to a heat treatment. The aim of the heat treatment was to shrink the individual filaments crimped in the texturing operation to eliminate again the bulkiness which arose in the texturing operation. Bonding of the individual filaments by the heat treatment was not provided so that the resulting strength of the cohesion of the thread composite was relatively low.

According to the present invention there is provided a method for producing a sewing yarn in which at least one multifilament main filament yarn is swirled with at least one melt-bonding multifilament bonding filament yarn by airstream *texturing and thereafter respective fixed lengths of the swirled yarn composite 4,re bonded together by a heat treatment initiating the bonding action of the bonding filament yarn, characterized in that the swirled yarn composite is stretched prior to the heat treatment.

Embodiments of the present invention provide a method of producing a sewing yarn with increased stability of the thread composite, and an apparatus for carrying out this method as well as a sewing thread which can be produced by said method. As the terms "thread" and "yarn" are conventionally used interchangeably, any reference made herein to either "thread" or "yarn" is to be read synonymously unless the contrary is indicated.

With regard to the method of a preferred embodiment, the swired thread composite is drawn or stretched prior to the heat treatment.

Initially, by way of the airstream texturing, loops and bends of the main filament threads and the bonding filament threads are distributed over the cross-section of the thread composite and, by their subsequent drawing or stretching, a controlled shortening and reduction of the 4 S90103p,WPFT.DIS2,,16215,spc,2 -3loops and bends is achieved. Thereafter this drawn filament thread composite shrinks in the treatment so that by this shortening of the loops and bends said composite is further consolidated. Simultaneously ,ith the shrinking operation, the heat being applied at the level of the melt temperature of the bonding filaments initiates the bonding effect thereof by the bonding filaments either being superficially melted or by being fully melted. The stresses occurring during the heat treatment in the thread composite promote a stable and compact bonding because the bonding operation takes place in the manner of a pressure bonding.

The airstream-textured single threads or simple threads made by the preferred 10 method according to the present invention achieve properties which are at least equal to those of comparable twisted threads. With regard to sewing properties, the sewing properties of conventional twisted yarns are even surpassed.

In another embodiment of the present invention there is provided a metaod 15 whereby the main filament threads and the bonding filament threads are fed to the airsu'eam texturing operation with different preadvance, By selectively setting this preadvance, for example, having a feed rate exceeding the removal rate, the form ard size of the loops and bends formed in the airstream texturing operation °can be controlled.

In this connection, one possibility of conducting the procedure resides in the main filament yarns being fed with slight preadvance, thus the individual filaments separate from each other and the bonding filament threads are supplied with higher preadvance. This means that in the airstream texturing operation, although the individual filaments of the main filament thread or threads move apart, they remain substantially parallel without forming loops and bends whilst the individual filaments of the bonding filament thread or threads having the greater preadvance are 9 1O;,WPFT.D ISK2,t6215.spe,3 -4blown in transversely to the thread direction between the individual filaments of the main filament thread or threads and, by way of the subsequent initiation of the bonding effect, the individual filaments of the main filament thread or threads mutually bond each other.

In yet another embodiment of the method of the present invention at least one further main filament thread is supplied with higher preadvance. Said further main filament thread may, for example, be in effect a filament thread, which forms, similarly to the bonding filament, thread loops and bends which penetrate between the individual filaments of the other main filament thread fed with low preadvance. As a result a well bonded core effect thread structure is achieved.

SIn a still further embodiment of the method of the present invention the main filament threads and the bonding filament threads are supplied to the airstream 15 texturing operation with substantially the same preadvance as the individual filaments of the main filament threads and the bonding filament threads are uniformly swirled together. This also gives the main filament ithread a loop structure leading to particularly good bonding.

In another embodiment of the method of the present invention the thread composite is cooled after the heat treatment. This cooling taking place directly after the adhering or bonding thereby accelerating the bonding operation and the hardening of the bonding.

9 Although excellent bonding is achieved by the various embodiments of the invention without yarn twisting being necessary, in another embodiment of the method of the present invention the thread composite is twisted 9010 WPFDSK2,16215.spe,4 i. before the heat treatment. This can be done in the same operation by false twisting or by twisting and subsequent further processing in a separate operation.

In yet another embodiment of the method of the present invention a postprocessing of the thread is possible in which the heat-treated thread composite is twisted.

In a p't'erred embodiment of tlir present invention there is provided an apparatus having on the entry side an airstream textuiring device which can be fed with at least one multifilament main filament thread and at least one multifilament bonding filament thread and a setting device which follows the airstream texturing device and in which the bonding action of the bonding filament threads, having a lower melting point than the main filament threads, can be initiated by a heat treatment of respective fixed lengths of the thread composite adapted to be fed from the airstream texturing device, which is characterized according to the preferred embodiment in that between the airstream texturing device and the setting device a stabilizing device is provided for stretching the thread composite supplied by the airstream texturing device.

S s 20 With the apparatus of the preferred embodiment the stretching operation see advantageous for the desired sewing thread structure and leading to a shortening and diminishing of the loops and bends produced in the airstream texturing can be carried out in simple manner. In addition, the apparatus of the preferred embodiment is distinguished by simple structure and can be implemented by conventional components of airstream texturing apparatus. The structure of the preferred embodiment leads to a trouble-free procedure with high productivity.

In a further embodiment of the apparatus of the present invention the airstream texturing device is preceded on 901030,WPFT'.DS2,16215.Spe,5 L the entry side by a preadvance system by which the supply speed for the individually set filament threads 9 selectively adjustable. By the different feeds or preadvances of the main and bonding filament threads to the airstream textur..

ing device the thread character of the threads made can be adapted to the desired application field.

In this connection, from the constructional point of view it is found oxpedient for the preadvance system for each main filament thread to be fed to have in each case two series-arranged pinch roller pairs, the feed speed of which is selectively adjustable. With this simple structure it is possible not only to individually adapt the feed or preadvance of the main filament threads fed to the texturing apparatus but between the respective series-arranged pinch roller pairs effecting the conveying of the main filament threads to carry out if necessary a stretching cf the main filament threads supplied. Such a stretching is necessary on the one hand when using preoriented main filament threads (POY threads) to achieve the final stretching suitable for the processing thereof. Another purpose however is to give the main filament threads a stretching serving to initiate shrinkage in the heat treatment.

In this connection, it is convenient from the structural point of view for the stabilizing device to have two pinch roller pairs spaced apart in the feed direction, the pinch roller pair arranged downstream in the feed direction having a higher conveying speed than the pinch roller pair arranged upstream. By this arrangement the thread composite can be held in conveying manner by each of the pinch roller pairs and simultaneously stretched in the desired manner due to the different feed speed between the pinch roller pairs.

Since the stabilizing device is arranged upstream of the setting device the downstream pinch roller pair of the stabilizing device can simultaneously serve to form the <i-6- -7entrance to the setting device and for the entrance-side length fixing of the thread lengths disposed in the setting device.

To implement the cooling operation provided in one embodiment of the method according to the present invention, in a further embodiment of the apparatus the setting device is followed on the exit side by a cooling device. It is particularly convenient for the cooling device to be arranged between an entrance-side pinch roller pair and a takeup device having a pinch roller and a takeup roller. Said entrance-side pinch roller pair of the cooling device may for example be formed by an exit-side pinch roller pair of the setting device which thus on the one hand defines the thread length provided in the setting device on the exit side and •simultaneously governs the supply for the thread length passing through the cooling device on the entrance side.

15 A sewing yarn made by embodiments of the method of the present invention comprise at least one bonding strand which is swirled with the main strand, is melt-bonding, is formed by a multifilament bonding filament thread and is superficially or fully melted in the thread composite for the bonding thereof, and is characterized according to the invention in that loops and bends, formed by the swirling, of the unmelted main filament thread or threads in the thread composite are contracted, seen in cross-section of the thread composite, to a size corresponding substantially to the cross-sectional size of the unswirled thread composite, The contracted state of the loops and bends gives the compact structure of the surface of the sewing thread necessary for sewing purposes which nevertheless still effects adequate entraining of cooling air during sewing. The swirl structure of the sewing thread according to the invention, as can be S'i 901030,WP K26 7 90103,WPFT.DlSK2,'.6215spe,7 -sa 8 achieved by previously proposed methods of airstream texturing in a texturing nozzle, provides particular favourable conditions for the bonding, i.e. the mutual adhering of the individual filaments of the filament threads which form the main strands and are therefore referred to as main filament threads, by means of the added bonding filament threads. By the joint swirling of the individual filaments of the multifilament thread or threads or the individual filaments of the multifilament bonding filament threads, at least one of the main or bonding filament threads exhibits loops and bends of its individual filaments which are distributed over the cross-section of the thread composite leading to a vry stable and homogeneously distributed bonding by means of the bonding filaments being superficially melted or by being fully melted in the bonding operation. Due to the high stability of the bonding of the thread composite thereby obtained thread s twisting may be dispensed with. If in the sewing thread of an embodiment of the o* present invention only a single main filament thread is provided, the loops and 15 bends of the individual filaments of the bonding filament thread extend transversely through the individual filaments of said single main filament thread and due to their bonding action caused by melting hold the individual filaments of the main filament thread together. The individual filaments of the main filament thread may extend substantially unswirled parallel to each other. A further enhancement of the cohesion in the thread composite is however achieved "in that the individual filaments of the main filament thread mutually interengage with loopa and bends produced in the swirling. For the case of an embodiment in which the thread comprises a plurality of main filament threads, the loops and bends of the individual filaments of the bonding filament thread penetrate the individual filaments of the various main filament threads.

In another embodiment of the sewing thread produced by the method of the present invention at least two main filament threads ar 1 K 9010O3,WPFT.DiSK2,16215spC,8 L; -9provided, it is found particularly advantageous that the individual filaments of the main filament threads with loops and bends are swirled together. Since, when this is done the individual main filament threads are mutually interspersed with the bends and loops of their individual filaments, and this interlaced structure is thus bonded at a great number of points by the bonding filament thread or threads, a particularly robust thread composite is obtained.

In such an embodiment of the sewing thread according to the preferred embodiment of the present invention in which at least two multifilament main filament threads are provided, an advantageous further development resides in that the individual filaments of the one main filament thread serving as a core extend substantially parallel and are permeated by the loops and bends formed

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by the swirling of the individual filaments of the other main filament thread.

Thus, in this embodiment of the main filament thread serving as the core 15 substantially no loops and bends are formed so that the cort gives a high tensile strength of the thread composite, Since however the loops and bends of the main filament thread serving pass through the substantially parallel extending individual filaments of the main filament thread serving as the core, in this case on bonding by means of the bonding filament thread or threads, a very well bonded thread composite is also obtained.

A possible material selection resides in that the main filament threads consist of .i a polyamide or polyester having a higher melting point than the bonding filament threads. In particular, it is advantageous for the main filament threads and/or bonding filament threads to have a large filament count. By this large filament count or capillaries a particularly good swirling effect is achieved.

Advantageously, the bonding filame--. 4 hreads consist of a copolymer, a copolyamide being particularly suitable as 90106WPFT,1i SK2,6215.spc,9 r--I copolymer. In this case the melting point of the bonding filament threads, which must be below that of the main filament threads to be bonded, can be selected between 60 and 160 °C and thus adapted to various types of use. The proportion of the copolymers forming the bonding filaments depends on the desired composite and the intended use. With high proportions of bonding filaments a highly bonded thread character is obtained whilst with low proportions of the bonding filaments a textile structure of the thread composite is retained which is, however, very well bonded.

The invention will now be further described by way of example only with reference to the accompanying drawings in which: 0S gg S 0 *c S S. S 4@ 00

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a 4k 1 02AV PFrO 1SK2,1621$.5p, -Il Figure 1 is a schematic view of an apparatus for implementing a method suitable for producing a thread composite from two main filament strands and one bonding filament strand, such an apparatus featuring an airstream texturing device and a setting device.

Figure 2 shows an application of the apparatus of Figure 1 suitable for prod,-ing a thread composite from only one main filament strand and a bonding filament strand, In Figure 1, an apparatus suitable for producing a sewing thread features a preadvance system 1 which, in the embodiment example illustrated, comprises three parallel feed path's for three filament strands that are to be united in a single thread composite. The number of feed paths indicated can vary according o to the embodiment, There must, however, be at least two feed paths.

Multifilament main filament strand 2, which thus features a plurality of single filaments and serves as the core, is drawn from a spool 3 and runs along one of the feed paths shown. The feed path assigned to main filament strand 2 features two pinch roller pairs 4, 4' installed in series in the feed direction, through whose pinch gap main filament strand 2 is permitted to *fee I i 4' 'B 901030.WPtTD5K2, 162 155pe, It 12 run practically without slipping. The strand is then advanced by a powered pinch roller pair 4, A further similarly designed feed path accommodates a further multifilament main filament strand serving as an effect and is drawn off from a spool 6. Reference numbers 7, 7' designate the pinch roller pairs assigned to '-he feed path of main filament strands $suh pinch roller pairs corresponding to the pinch roller pairs 4, 4' of the feed path of main filament strand 2. The third feed path is designed to accommodate a multifilament o0 bonding filament strand 10 that is drawn from spool 8, whereby only a single, powered pinch roller pair 9 is installed.

The advancement speed of pinch roller pairs 4, 4' of main filament s3trand 2 can be adjusted independently of each other, which permits the speed of the downstream roller pair 4' to be increased beyond that of upstream roller pair 4, and main filament strand 2 to be stretched between pinch roller pairs 4, The speeds of pinch rollers 7, 7' can similarly be adjusted, thus permitting main filament strands to be stretched. Bonding filament strand 10 is, by contrast, not to bf stretched.

The stretching operation taking place between pinch roller pairs 4, 4' or 7, 7' can be a cold stretching operation preparatory to a subsequent shrinking step. When preoriented or main filament strands are employed, a hot stretching process is required in in ii 1 -1 13 of the POY main filament strands.

Preadvance system 1 feeds bonding filament strand 10 to airstream texturing device 11i, in which filament strands 2, and 10 are combined into a single thread composite and swirled together by the airstream produced by the texturing nozzle located inside airstream texturing device 11. Main filament strand 2, which acts as the core, is run through water before being exposed to the airstream. This swirling eho 3er> Pevtoesk Proposec\ method is wl- kno-wnPand need not be discussed any further in this disclosure. It should be noted, however, that pinch roller pairs 7' and 9 can, depending on the type of swirling required, be adjusted to specific rates of preadvance speed.

Swirling in the texturing nozzle causes bonding filament strand 10 and main filament strands 2 and 5 to combine and intertwine, whereby loops and bends are produced in the individual filaments during the swirling process.

The multifilament main filament strand 2 that serves as the core can also be advanced, for example, by means of pinch roller pair 4' of airstream texturing device 11 and by means of a relatively slight preadvance sufficient to cause the individual filaments of main filament strand 2 to separate, whereby on the other hand main filament strand 5 serving as the effect is advanced at a relatively higher rate of preadvance. This process causes loops 4i 14 and bends to form basically on the individual filaments of the main filament strand acting as the effect while the loops and bends penetrate the cross section of the essentially parallel individual filaments of main filament strand 2 serving as the core. Bonding filament strand 10 can be advanced at a rate of preadvance equal to or higher than that of main filament strand 5 that serves as the effect, for the purpose of acnieving a more intense distribution of its individual filaments throughout the cross section of main filament strands 2, 5. Alternatively, main filament strands 2, 5 can also be advanced at the same high rate of preadvance, whereby both main filament strands 2, 5 can be blown together more or less evenly.

A stabilizing device 12 located downstream of airstream texturing device 11 and serving to stabilize the thread composite 13 features two pinch roller pairs 14, 14' located in series in the feed direction and between each of whose pinch gaps is conveyed thread composite 13 practically without slippage. A slave roller 15 situated between roller pairs 14, 14' serves merely to redirect the length of strand stretched between rollers 14, 14'. The advancement speed of downstreamsituated pinch roller pair 14' is adjusted higher than the advancement speed of the upstream-situated pinch roller pair 14, which determines the speed at which thread composite 13 is taken up from airstream texturing device 11. The thread composite 13, already textured by the s and beds are reduced and partially drawn together. This 1 airstream procedure, is thus stretched to the extent permitted by the advancement speed selected, whereby the loops and be,.ids are reduced and partially drawn together. This procedure causes the thread composite, which comprises main filament strands 2, 5 and bonding filament strand 10 to densify.

After leaving pinch roller 14, the uncompressed thread composite enters setting device 16, at whose exit side the thread composite is redirected by a slave roller 17 through pinch roller pair 18 which serves to guide and advance such thread composite. A heat treatment procedure takes place in setting device 16 and causes main filament strands 2 and 5 to shrink, so that the length of thread composite held between roller pairs 14' and 18 undergoes tensile stressing. The magnitude of such tension is determined by adjusting the advancement speed of pinch roller pairs 14' and 18. Such heatinduced shrinkage can in this case increase the advancement speed of pinch roller pairs 14 beyond that of pinch roller pair 18. The temperature of the heat treatment process is meanwhile adjusted until the melting point of the bonding filament strand 10 in the strand composite is reached, whereupon the bonding filament strand melts, in contrast with main filament strands 2 and 5, which feature higher melting points. The entire thread compOsite is now subjected to tensile stress. Carried out under tensile stress, the conglutination process is imposed upon the somewhat bulky thread composite 13 leaving the'airstream ,j 16 1 texturing device 11, and produces an effectively bonded thread composite.

Located downstream of the exit-side pinch roller pair 10 of setting device 16 are slave guide rollers 19, 20 that redirect the thread composite to a take-up roller 22 that cooperates with a pinch roller 21. A cooling device 23 is arranged behind pinch roller pair 18 in the zone traversed by the thread composite between pinch roller pair 18 and the pinch gap existing between pinch roller 21 and take-up roller 22. The thread, in passing along this cooling device 23, is cooled off for the purpose of accelerating bonding and the hardening of the bond. The descr:ibed opterating sequence also affords a view of the structure of th' swirled thread conposite 13 as it leaves the airstream texturing device. Such a swirling process produces in filament strands 2, 5 and loops and bends that are then able to penetrate the thread composite in the direction of its cross section and thus produce a somewhat irregular, bulky thread composite surface.

The heat process that takes place in setting device 16 causes, on the other hand, the external surface structure of the thread composite to densify. As can be gathered from the overview of the process, main filament strands 2, 5 of the finished thread composite feature no mutual twisting.

Dr4w 1 2 presents a process suitable for use in the proposed \f019303WPFT.DISK2,16215.spe,3 17 1 device if only a single multifilament main filament strand 2 IT is to be combined with a single bonding filament strand 10. In this process the feed path defined by pinch roller pairs 7, 7' is not used. This process also permits the use of varying rates of preadvance for main filament strand 2 and bonding filament strand 10. Main filament strand 2 can, fir example, be fed with a relatively slight preadvance sufficient to provoke the mutual separation of its individual filaments when exposed the airstream in texturing device 11, while the bonding filament strand 10 undergoes preadvance sufficient to form loops and bends in its individual filaments. Thus, bonding filament strand 10 can be distributed throughout the cross section of main filament strand 2. Alternatively, main filament strand 2 and bonding filament strand 10 can be advanced at approximately the same rate of preadvance, in order for the loops and bends of the individual filaments of the main filament strand 2 and bonding filament strand 10 to intermingle. Main filament strand 2 and bonding filament strand 10 can, in contrast to the operation shown inkiDr-ain 2, be guided parallel to each other through the airstream texturing device by means of a single pinch roller pair.

As can be seen in the operation sequences illustrated by raw-ingsf 1 and 2, the thread composite does not undergo twisting. Should twisting however be desirable, the thread composite already conglutinated in setting device 16 can be twisted in a separate A. lo/ f 18 1 process following the described operation. Alternatively, once the strand has left airstream texturin device 11 or stabilizing device 12, it can be bonded in a separate operation in which bonding is triggered. It is finally also possible to impart a false twist to such thread as it traverses setting device According to the preceding description, the sole precondition for the effective operation of the method implemented on the described apparatus is that the bonding filament strands feature a lower melting point than the main filament strand(s) 2, 5. Regarding the choice of materials in particular, a copolymer, more particularly a copolyamide, should be considered as the bonding filament strand. The melting point of the bonding filament strands should lie between 60 and 160 0 C. For the purpose of the present operation, the main filament strands should consist of polyamide or polyester.

Main filament strands featuring a high filament count are particularly suitable, as they permit the production of numerous loops and bends and thus the achievement of a particularly solid thread composite.

3 4 i

Claims

1. Method for producing a sewing yarn in which at least one multifilament main filament yarn is swirled with at least one melt-bonding multifilament bonding filament yarn by airstream texturing and thereafter respective fixed lengths of the swirled yarn composite are bonded together by a heat treatment initiating the bonding action of the bonding filament yarn, wherein the swirled yarn composite is stretched prior to the heat treatment. 10 2. Method according to claim 1, wherein the melting temperature of the main 6filament yarn lies above the melting temperature of the bonding filament yarn.

3. Method according to claim 1 or 2, wherein the main filament yarns and the bonding filament yarns are supplied to the airstream texturing operation with different preadvance.

4. Method according to claim 3, wherein the mrain filament yarns are supplied see with low preadvance at which the individual filaments only mutually separate and the bonding filament yarns are supplied with higher preadvance.

5. Method according to claim 4, wherein at least one further main filament yarn is fed with higher preadvance.

6. Method according to claim 1 or 2, wherein the main filament yarns and the bonding filament yarns are fed to the airstream texturing operation with substantially the same preadvance at which the individual filaments of the main filament yarns and of the bonding filament yarns are uniformly swirled with each other.

7. Method according to any one of claims 1 to 6, wherein the yarn composite is cooled after the heat treatment. Wtf WPFT,DISK2,16215,Spe,19 L 2 901030,WPFIr.DSK.Z6215 spe,7

8. Method according to any one of claims 1 to 7, wherein the yarn composite is twisted prior to the heat treatment.

9. Method according to any one of claims 1 to 8, wherein the heat-treated yarn composite is twisted. Apparatus for carrying out the method according to any one of claims 1 to 9 having an airstream texturing device which can be fed on the entry side with at least one multifilament main filament yarn and at least one multifilament 10 bonding filament yarn and a setting device which follows the airstream texturing device and in which the bonding action of the bonding filament yarns having a be lower melting point than the main filament yarns can be initiated by a heat treatment of respective fixed lengths of the yarn composite adapted to be fed from the airstream texturing device wherein beitvieen the airstream texturing device and the setting device a stabilizing device is provided for stretching the yarn composite supplied by the airstream texturing device. o*

11. Apparatus according to claim 10, wherein the stabilizing device comprises two pinch roller pairs which are spaced apart in the conveying direction and of 20 which the pinch roller pair arranged downstream in the conveying direction has a higher conveying speed than the pinch roller pair arranged upstream. *s ,s

12. Apparatus according to claim 10 or 11, wherein the airstream texturing device is preceded on the entrance side by a preadvance system by which the feed speed for the individual filament yarns supplied is selectively settable.

13. Apparatus according to claim 12, wherein the preadvance system for each main filament yarn to be supplied has two series-connected pinch roller pairs of which the feed speed is selectively settable.

14. Apparatus according to any one of claims 10 to 13, wherein the setting device is followed on the exit side by a cooling device. 'V OWPFrDISK2,16215.spe,20 1 901030,WPFT.DISK2,16215.spe,8 Si 21 Apparatus according to claim 14, wherein the cooling device is arranged between an ientrance-side pinch roller pair and a takeup device having a pinch roller and a takeup roller. 16, Sewing yarn made by the method according to any one of claims 1 to 9 and comprising at least one main strand formed by a multifilament main filament yarn and at least one bonding strand formed by a multifilament bonding filament yarn which is swirled with the %ain strand, is melt-bonding and is superficially melted or fully melted in the yarn composite for the bonding thereof, wherein loops and 10 bends, formed by the sw iling, of the main filament yarn or yarns which are unmelted in the yarn composite are contracted, seen in cross-section of the yarn composite, to a size corresponding substantially to the cross-sectional size of the unswirled yarn composite.

17. Sewing yarn according to claim 16 in which at least two multifilameit main filament yarns are provided, wherein the individual filaments of the main filament yarns with loops and bends are swirled together.

18. Sewing yarn according to claim 17, wherein the individual filaments of the main filament yarn serving as core extend substantially parallel and are permeated by the loops and bends, formed by the swirling, of the individual filaments of the other main filament yarn serving as effect,

19. Sewing yarn according to any one of claims 16 to 18, therein the main fil~ndnt yarns consist of a polyamide or polyester having a higher melting point than the bonding filament yarns. Sewing yarn according to any one of claims 16 to 19, wherein the main filament yarns and/or bonding filament yarns iav e high filamen count.

21. Sewing yarn according to any one of clains 16 to 20, wherein the bonding filrnents are a copolymer. S 0 ,WPFT ISK2,1215.spe,21 filmen yan n/rbnigflaetyrsla. ih iaet oniI 9010 PFDDISK2,16215.spe,9 -22 22, Sewing yarn according to claim 21, wherein the copolyme, is a copolyam ide.

23. Sewing yarn according to any one of claims 16 to 22, wherein the melting point of the bonding filaments lies between 60 and 160 "C.

24. A method for producing a sewing yarn substantially as hereinbefore described with reference to the accompanying dravings.

25. Sewing yarn made by the method defined by any one of claims 1 to 9,

26. An apparatus for producing a sewing yarn substantially as hereinbefore described with reference to the accompanying drawings.

27. A sewing yarn substantially as hereinbefore described with reference to the accompanying drawings. 06 1.5.I. ACKERMANN-GOGGINGEN AG DatedBy its Patent Attorneys D DAVIES COLLISON I -90i0 ,WP ,DISIz1621 spe,2