GB2043731A

GB2043731A - A multifilament thread composed of single filaments of the multi-component matrix-segment type

Info

Publication number: GB2043731A
Application number: GB8007193A
Authority: GB
Original assignee: Akzo NV
Current assignee: Akzo NV
Priority date: 1979-03-02
Filing date: 1980-03-03
Publication date: 1980-10-08
Also published as: BE881997A; CH642510B; IT1143074B; IT8048042A0; AU5601580A; FR2450297B1; AT383158B; NL8001195A; JPS55148230A; GB2122227B; CH642510GA3; DE2908101A1; CA1126105A; ATA112080A; FR2450297A1; ES489098A1; AU532716B2; GB2122227A

Abstract

A multifilament thread composed of single filaments of the multi-component matrix-segment type. The single filaments comprise a matrix (a) and at least three segment fibres separated therefrom (b), which are shrunk by at least approximately 10% with respect to the matrix (a). The individual components forming the thread exhibit a false twist crimp and are bonded entirely or partially in the thread at irregular intervals by means of bonding points which partially or completely extend through the thread cross section. A method for producing such threads is also provided as are flat structures such as woven, knitted and non-woven cloth formed therefrom.

Description

SPECIFICATION A multifilament thread composed of single filaments of the multi - component - matrix - segment type The present invention relates to a multifilament thread composed of single filaments of the multicomponent matrix-segment type in which the single filaments comprise a matrix and at least three segment fibres separated thereby, wherein the segment fibres are shrunk by at least approximately 1 oO/o with respect to the respective matrix fibre. It also relates to a method of producing a thread according to the invention and flat structures formed therefrom.

Threads composed of single filaments of the multi-component matrix-segment type are described for example in German Patent Applications P 2803 136.9 and P 28 09 346.1, and are therefore pertinent to the present disclosure in this respect. They consist of at least two different polymers having a distinctly different shrinkage behaviour.

Thus, by liberating the differential shrinkage a complete or partial separation of the components can be obtained.

It has now been found that surprising effects are produced in false twist texturing threads of the type described above under particular conditions, by the correct selection of the polymers processed together and ofthetexturing conditions.

Therefore, an object of the present invention is the preparation of a thread composed of single filaments of the multicomponent-matrix segment-type which can without twisting, sizing or other treatment methods for producing a final thread be easily processed into a flat structure and in which, in the finished flat structure, the components forming the thread have a very fine individual titre.

According to the present invention there is provided a multifilament thread composed of single filaments of multi-component matrix-segment type, wherein the single filaments comprise a matrix and at least three segment fibres separated thereby, the segment fibres being shrunk by at least approximately 10% with respect to the matrix and the individual components forming the thread exhibit a false twist crimp and are bound entirely or partially in a thread bundle at irregular spacings by means of adherence points which partially or completely extend through the thread cross section.

Thereby, the matrix component can be made of polyamide and the segment component can be made of polyalkylene terephthalate. A combination in which the matrix component is made of polycaprolactam and the segment component is made of polyethyleneterephthalate is particularly suitable.

According to the invention, the weight ratio between the matrix and segment components should be approximately from 5:95 to 45:55 and preferably approximately from 10:90 to 25:75.

According to a further aspect of the invention there is also provided a method of producing a multifilament thread according to any of claims 1 to 17, wherein a multifilamentthread consisting of single filaments of the multi-component matrix-segment type is subjected to a false twist treatment, in which a fixing temperature is used which at least corresponds to that which is necessary for the component having the lowest melting temperature, and twist level of approximately from 1500 to 4500 twists per metre is selected dependent on the total titre of the multifilament thread.

The fixing temperature is thereby advantageously in the range approximately from 1 80 C to 240 C and preferably in the range approximately from 1 90 C to 230"C.

It has been shown that tho twist level in the fixing stretch is preferably selected so that it corresponds to the conventional twist level when texturing a normal multifilament polyethylene terephthalate thread of approximately the same titre.

In the present context, the term "threads" is defined to include flat structures such as, for example, woven, knitted, deposited and non-woven cloth, in addition to continuous multifilament linear structures composed of continuous or staple fibres.

Preferably, the multifilamentthread composed of single filaments of the multi-component matrixsegment type according to the invention is subjected to a false twist treatment at a fixing temperature of from approximately 190 to 240"C, after which it exhibits approximately from 10 to 40 adherence points per metre and is then processed into a flat textile structure; the flat textile structure is then subjected to simultaneous shrinking and fulling treatment in an organic solvent, which lowers the zero shrinkage temperature of the segment polymer or the segment polymers by at least 1 60 C. The fulling treatment should be very intensive, thereby avoiding, in particular, subsequent change in feel during use.

The draw-texturing method is used particularly advantageously for the false twist method, in which the drawing ratio is selected in a manner known per se to suit the required final product.

Methylene chloride, 1,1 2,2-tetrachloroethane, 1,1,2-trichloroethane and chloroform have proved to be particularly effective organic solvents.

Being capable of shrinking in the present context means that the segment component fibres are caused to shrink, as a result, for example, of the treatment according to the invention using the solvents stated.

It is important that the segment components exhibit a noticeable shrinkage in the solvents stated in accordance with the invention; this shrinkage should approximately be of at least 1 oO/o, a shrinkage of at least 15% being preferred. The average skilled man is familiar with the method here for ascertaining the shrinkage behaviour.

It is important that the matrix and segment components exhibit a different shrinkage behaviour in the solvent; e.g., the segments are shrinkable while the matrix is not. The difference can also lie in the shrinkage being different in its extent. However, it is essential that the induction time e.g. the time up to which the shrinkage in the treatment medium gains noticeable dimensions, is different. It is important for the method the invention that the induction time for the shrinkage is as short as possible for the segment components and preferably is only in the order of seconds. The difference in the shrinking behaviour can also be achieved by the peripheral segments having a faster shrinkage rate than the matrix.

Details concerning the determination of the induction time can be found in the two publications by N.L. Lindner in the periodical Colloid and Polymer Sci.255, pages 213 and following, and 433 and following (1977).

Afurther object related to the present invention is the production of worked, knitted or woven flat structures having particular feel and wear properties.

According to a still further aspect of the invention there is also provided a worked, knitted or woven textile flat structure comprising threads which are entirely or partially false - twist - textured multifilament threads composed of single filaments of multi-component matrix-segment type, which comprise a matrix and at least three segment fibres separated thereby, the segment fibres being shrunk by at least approximately 10% in respect of the matrix, wherein the individual components forming the multifilament threads are respectively bound entirely or partially in each thread at irregular spacings by means of adherence points which partially or completely extend through the individual thread cross section.

The invention will be further described with refer ence to the following Example: Multifilament threads composed of single filaments of the multi-component matrix-segments type were subjected to a false twist treatment at a fixing temperature of approximately from 190 to 240 C, after which they exhibited approximately from 10 to 40 adherence points per metre. When they had then been processed into a flat textile structure, they were subjected to a simultaneous shrinking and fulling treatment in an organic solvent, which lowers the zero shrinkage temperature of the segment polymer or the segment polymers by at least 100"C. The fulling treatment was very intensive, thereby avoiding, in particular, a subsequent change in feel during use.

The threads in the finished, post-treatment flat structure were reduced in their adherence points by approximately from 50 to 80%.

It is particularly advantageous, that the threads which are used for the flat structures of the invention be draw-textured using a drawing ratio which is selected in a manner known per se to suit the required final product.

It is thus possible to achieve a wide palette of different so-called shade of touch by suitable selection of the fixing temperature with regard to the effect in the flat structure. Thus, during the treatment using the solvent, particular significance is attributed to the simultaneous fulling treatment. It must be so thorough that, for instance, by the releasing of further adherence points or by other separation steps between matrix and segment components, the feel of the cloth will not change anymore during wear or use.

The separation of the textured multi-component threads, particularly the releasing of the adherence points is advantageously effected after the processing according to the invention ofthetextured multi-component threads into textile and commercial structures.

Flat structures of the invention such as worked, knitted and woven cloth are produced particularly advantageously in that a textured thread of the invention is produced which, as a result of the heat treatment during texturing gains at least approximately 10, but at the most not more than 40 adherence points per metre of th read length.

The threads of the matrix-segment type to which the invention relates are composed of polymers which cannot be mixed together and do not enter into a chemical reaction with each other and which, for example, when mixed together in the melt or spun as components concurrently into a multicomponent fibre, exhibit in particular, a distinct phase limit under the stated conditions. Polyamides and polyesters belong predominately to this type of incompatible polymer, and thus polyesters based on terephthalic acid are preferred. Both these polymers do not show any noticeable chemical reaction with each other in the melt, at least within well defined times, so that practically non, or scarcely any mixed polymers are formed which would bond the two phases more firmly together.

It is evident that exchange reactions which could occur between polyesters and polyamides in the melt within longer periods of time, as they are described for example in Doklady Akademii Nauk SSSR 1962, Vol. 147, No. 6, Page 13, 165 to 8, are not considered.

The term "matrix-componentthreadswith a matrix and multi-segment-like arranged components" is to be understood to describe threads in which the individual segments and the matrix are arranged continuously along the thread axis, so that the thread cross-section is substantially constant over the thread length. Examples of thread cross-sections which are suitable within the scope of the invention are shown in Figures 1 to 7 of the accompanying drawings, in which the matrix is marked with "a" and the segments are marked with "b".

In the present context, the term "organic solvents" is to be understodd to describe chemical substances which are able physically to form a solution with other substances. It is not necessary, and is even usually undesirable for the solvents to themselves dissolve one or all polymers of which the multicomponent fibres are composed. However, in excepted cases, it should be appropriate, for example, to completely or partially release the matrix component after processing into a flat structure. The solvent should shrink the segment fibres as much as possible, the matrix however should shrink only slightly or not at all.

The zero shrinkagetemperatures can beestab- lished according to a method which is explained, for example, in Lenzinger Berichte May 1976, Edition 40, Page 22 to 29, in which dynamic shrinkage curves of threads are established in the solvent which is involved in the treatment of the multi-component threads. The extrapolation of the linear part of the dynamic shrinkage curve produces the zero shrinkage temperature at the point of intersection with the abscissa.

It has been shown that, in particular, the solvent mentioned above, methylene chloride, 1,1,2,2, tetrachloroethane, 1,1 2-trichloroethane and chloroform, lower the zero shrinkage temperature of the segment polymer sufficiently and cause an unexpectedly favourable separation of the multi component threads in accordance with the inven tion.

Multi-component threads of the type required according to the invention as a starting material can be produced in different ways by spinning the suit able polymers according to the melt spinning method by using corresponding nozzles or spinning devices, and by drawing the polymers out in the conventional manner. These types of multi component threads can be produced particularly advantageously by means of a method and an apparatus described in German Patent Application P 28 03 136.9.

According to the invention, the selection of the parts (by weight) of the matrix and segment compo nents also plays an important part. It has been shown that particularly with threads in the range of approximately from 10 to 25% by weight of matrix component, releasing the adherence points is greatly facilitated in particular when fixing temperatures of approximately from 225 to 230"C are not exceeded at the most approximately 235 C.

The distribution of the matrix and segment com ponents, the amount of the applied twist and particu marly the level of the fixing temperature are generally decisive as to the structure of the finished thread of the invention. In particular it has been shown that in order to achieve the effect of the invention at all for thermal fixation a temperature has to be selected which at least corresponds to that which is necessary as a fixing temperature for that material of the thread component having the lowest melting point, i.e. of the thread component forming the matrix.

The more this temperature is exceeded, the greater the number not only of adherence points which are present after the texturing process but also of the adherence points which can no longer be released.

It is thus possible to achieve a board palette of different so-called shades of touch by means of suitable selection of the fixing temperature with regard to the effect in the flat structure. Thus, a particular significance is attributed to the simultaneous fulling treatment in the treatment using the solvent. It has to be so thorough that, for instance, by releasing other adherence points or by other separation steps between the matrix and segment components, the feel of the cloth cannot change anymore during wear or when used.

The matrix profile is selected depending on the final characteristics required. The finer the individual segment titres are required to be, the greater are the number of segment components that there must be per matrix component.

Separating the textured multi-component threads, in particular, releasing the adherence points, cannot only be effected on structures such as staple fibres or continuous threads, but in particular, can also be effected in structures which have been acquired by processing the textured multi-component threads into textile and commercial structures.

Flat structures such as worked, knitted and woven cloth are produced particularly advantageously according to an aspect of the invention in that a thread textured according to the invention is pro vided which acquires at least approximately 10, however at the most not more than 40 adherence points per metre of thread length during texturing as a result of the heat treatment.

Indeed, there can also be cases in which one thread, exhibiting only however very few points with still recognisable single filaments, which thread being very similar two a monofilament in its proces sing behaviour, is particularly interesting due to its heavily textured surface. These cases are in this respect also encompassed by the invention, how ever they constitute only a peripheral objective.

In particular, when the matrix component of the threads provided is in the lower range, for instance up to approximately 15% by weight, the selection of a corresponding fixing temperature with which texturing can result is such that the segment compo nents in the finished thread can scarcely be made out, while the matrix becomes torn and adheres to the segment fibres to varying extents, their dimensions lying to some extent below the resolving power of a light-optical microscope. In such cases, it can be very advantageous to release the matrix components from the flat structure so that only the very fine titred segment components (for example having individual titres of approximately from 0.1 to 0.3 dtex) are present.

Claims

1. A multifilament thread composed of single filaments of multi-component matrix-segment type, wherein the single filaments comprise a matrix and at least three segment fibres separated thereby, the segment fibres being shrunk by at least approximately 10% with respect to the matrix and the individual components forming the thread exhibit a false twist crimp and are bound entirely or partially in a thread bundle at irregular spacings by means of adherence points which partially or completely extend through the thread cross section.

2. A thread according to claim 1, wherein the matrix component comprises polyamide.

3. A thread according to claim 1 or 2, wherein the segment component consists of polyalkylene terephthalate.

4. A thread according to any preceding claim wherein the matrix component comprises polycaprolactam.

5. A thread according to any preceding claim, wherein the segment component comprises polyethylene terephthalate.

6. Athread according to any preceding claim, wherein the weight ratio between the matrix and segment components thereof is in the range approximately from 5:95 to 45:55.

7. Athread according to claim 6, wherein the weight ratio between the matrix and segment components thereof is in the range approximately from 10:90 to 25:75.

8. Athread according to any preceding claim, wherein at least six segment components are allocated to one matrix component.

9. A thread according to any preceding claim, wherein the segment components have individual titres in the range approximately from 0.08 to 2.0 dtex.

10. Athread according to claim 9, wherein the segment components have individual titres in the range approximately from 0.1 to 1.4 dtex.

11. Athread according to any preceding claim, wherein the false twist crimp has an intensity in the range approximately from 1500 to 4500 twists per metre.

12. Athread according to any preceding claim, wherein the number of the adherence points binding more that two individual components together is on average in the range approximately from 5 to 40 per metre.

13. Athread according to any preceding claim, wherein after processing the thread initially having approximately from 10 to 40 adherence points per metre into a flat structure and subjecting the flat structureto a treatment in an organic solvent lowering the zero shrinkage temperature of the segment polymer by at least 160 > C, together with filling treatment approximately from 50 to 80% of the adherence points are released.

14. Athread according to claim 13, wherein methylene chloride was used as a solvent.

15. Athread according to claim 13, wherein 1,1 ,2,2,-tetrachloroethane was used as a solvent.

16. Athread according to claim 13, wherein 1,1,2-trichloroethane was used as a solvent.

17. Athread according to claim 13, wherein chloroform was used as a solvent.

18. A worked, knitted or woven textile flat struc to rue comprising threads which are entirely or partially false-twist- textured multifilament threads composed of single filaments of multi-component matrix-segment type, which comprise a matrix and at least three segment fibres separated thereby, the segment fibres being shrunk by at least approximately 10% in respect of the matrix, wherein the individual components forming the multifilament threads are respectively bound entirely or partially in each thread at irregular spacings by means of adherence points which partially or completely extend through the individual thread cross section.

19. A flat structure according to claim 18, wherein the multifilament individual threads forming the flat structure have at least 10 adherence points per metre length.

20. A flat structure according to claim 18 or 19, the multifilament individual threads forming the flat structure have up to 40 adherence points per metre length.

21. A method of producing a multifilament thread according to any of claims 1 to 17, wherein a multifilament thread consisting of single filaments of the multi-component matrix-segment type is subjected to a false twist treatment, in which a fixing temperature is used which at least corresponds to that which is necessary for the component having the lowest melting temperature, and twist level of approximately from 1500 to 4500 twists per metre is selected dependent on the total titre of the multifilament thread.

22. A method according to claim 21, wherein the fixing temperature is selected to be in the range approximately from 180 C to 240 C.

23. A method according to claim 22, wherein the fixing temperature is selected in the range approximately from 190 C to 230"C.

24. A method according to any of claims 21 to 23, wherein the twist tightness in the fixing stretch corresponds approximately to the conventional twist level when texturing a normal multifilament polyethylene terephthalate thread of approximately the same titre.

25. A method according to any of claims 21 to 24, wherein a multifilament threads comprising single filaments of the multicomponent matrix-segment type is subjected to a false twist treatment at a fixing temperature of approximately from 190 to 240 C, after which is exhibits approximately from 10 to 40 adherence points per metre and is then processed into a textile flat structure, whereupon the textile flat structure is subjected to a simultaneous shrinking and filling treatment in an organic solvent, which lowers the zero shrinkage temperature of the segment polymer or the segment polymers by at least 160 C.

26. A method according to any of claims 21 to 25, wherein the false twist method is a draw-texturing method, in which the drawing ratio is selected in a manner known per se to suit the required final product.