US3396529A - Elastic yarn process and product - Google Patents

Description

United States Patent 3,396,529 ELASTIC YARN PROCESS AND PRODUCT Otto T. Stutz, Wattwil, Switzerland, assignor to Heberlein Patent Corporation, New York, N.Y., a corporation of New York No Drawing. Filed Dec. 29, 1965, Ser. No. 517,422 Claims priority, applicatigri/sggitzerland, Jan. 13, 1965,

24 Claims. (Cl. 57140) ABSTRACT OF THE DISCLOSURE A process comprising temporarily high-twisting a synthetic multifilament yarn having at least one coarse filament with a titer greater than 6 denier and a plurality of finer individual filaments having a titer less than 6 denier, heat-setting the highly twisted yarn, and then releasing the twist; and synthetic multifilament yarns so produced.

This invention relates to an elastic yarn process and product, and more particularly, it relates to a process for making a highly elastic yarn and to the novel yarn obtained thereby.

It is known that elastic crimped yarn can be made by temporary high-twisting of synthetic multifilament yarns and heat-setting the yarns while they are temporarily highly twisted. Attempts have also been made to manufacture yarns having a high elastic extension by the aforesaid temporary high-twisting and heat-setting. A yarn with a high elastic extension is one which resists any elongation or tensile stress and resumes its original shape and length as quickly and as completely as possible after relaxation of the stress.

In prior attempts to produce yarns with high elastic extension, multifilament yarns consisting of individual filaments with a titer of 3-4 denier have been subjected to temporary high-twisting by means of a false-twisting device and heat-set in the highly twisted state at temperatures which are relatively close to the fusion point of the fiber material. Thereafter, two yarns which have been hightwisted in opposite directions are ply-twisted with a relatively large twist on the order of 200-400 turns per meter. These attempts to make a highly elastic yarn have produced unsatisfactory products, however, because relatively coarse filaments have been used in order to obtain the high elastic extension, and a rough, undesirable hand which is unsuitable for textile materials is obtained.

This inventiion provides a process for the production of a highly elastic yarn which has a desirable hand. This invention also provides a highly elastic yarn with a desirable hand suitable for textile uses.

Further and more specific objects, features, and advantages will clearly appear from the detailed description given below.

The invention comprises the novel products as well as the novel processes and steps of processes according to which such products are manufactured, the specific embodiments of which are hereinafter described by way of example and in accordance with which it is presently preferred to practice the invention.

Briefly, the process of this invention comprises temporarily high-twisting a multifilament yarn containing at least one synthetic core filament with a titer above about 6 denier and a plurality of synthetic filaments having a titer less than 6 denier and heat-setting the highly twisted multifilament yarn to make the multifilament yarn highly elastic. The high twist is then released from the yarn. The product of this invention is a highly elastic yarn comprising at least one highly-twisted and heat-set synthetic filament having a titer greater than about 6 denier and a plu- "ice rality of highly-twisted and heat-set synthetic filaments with a titer less than 6 denier. In certain aspects of this invention, the highly elastic yarn is combined with further yarn components.

The highly elastic textile yarn of this invention possesses a high elastic extension and an agreeable soft hand. Accordingly, the yarn of this invention is excellent for use in the manufacture of elastic knitwear and woven goods, and such yarn is especially useful for the production of sportswear such as ski trousers, swimwear, and the like. Such yarns can be used in lieu of elastomer synthetic stretch yarns.

The yarn of this invention preferably has a total titer of between about 30 and about 200 denier. The coarser filament or filaments preferably have a titer of from about 8 to about 20 denier, while a plurality of finer individual filaments preferably have individual titers in the range of between about 2 and about 5 denier.

In one aspect of this invention the individual filaments of the multifilament yarn can have differently shaped cross-sections. It is for example possible to utilize multifilament yarns, the components of which consist of individual filaments having a trilobal cross-section. Moreover, in certain embodiments of this invention one or more of the coarser filaments can be hollow.

The synthetic multifilament yarns can 'be made by laying or otherwise combining the coarser filament or filaments with the plurality of finer individual filaments. The multifilament yarns treated according to this invention can also be produced directly in the spinning operation through the use of a spinneret with differently sized and/ or configured spinning holes.

The synthetic multifilament yarns of this invention can be made from a wide variety of materials. The yarns are composed of synthetics which are desirably those having a relatively sharp softening or melting point. Thus, the synthetic multifilament yarns of this invention can comprise polyester fibers such as polyethylene-glycol-terephthalate and the like or polyolefins such as polypropylene and the like. It is especially preferred to use multifilament yarns consisting of polyamides, such as polyhexamethylene adipamide (nylon 66), condensation products of eaminocaproic acid (nylon 6) or ll-aminoundecanoic acid (nylon 11), and the like and combinations thereof.

In certain preferred aspects of this invention the crimped synthetic multifilament yarn is combined with additional yarn components. Thus the crimped highly elastic multifilament yarn can be wrapped with staple fibers of natural or synthetic material. Such staple fibers used in the practice of this invention can be natural fibers of animal or vegetable origin such as wool, cotton, and the like, artificial fibers such as those prepared from viscose rayon and the like, or synthetic materials such as those set forth above, as well as polyacrylonitrile and the like.

Moreover, it is advantageous in some instances to plytwist two crimped synthetic multifilament yarns which have been temporarily high -twisted in opposite directions. These multifilament yarns can be twisted or ply-twisted with from about 50 to about 600 turns per meter. It will be understood that one or both of such crimped multifilament yarns can be wrapped with staple fibers prior to ply-twisting them.

The crimping of the multifilament yarns is preferably carried out by means of a false-twisting device, wherein the yarns are conducted through hot air or over a heated surface after they are temporarily highly twisted for the purpose of heat-setting them. In such process the synthetic yarn is given a temporary high-twist on the order of thousands of turns per meter and then heated to a temperature somewhat below its fusion point. The yarn is then cooledto' temperature substantially below the fusion point So as permanently "to fix the twist in the yarn and the twist is released to provide a highly elastic yarn. In the ply-twisting operation, where desired, various types of twisting machines, such as ring or up-twisters with or without a hollow Spindle can be used. It will be understood herein that such false-twisting is used in practicing some aspects of this invention.

The elastic extension of the yarn as used herein is determined according to the following procedure:

Five strands of eight turns of yarn, each one meter long, are unwound from cross bobbins on which the yarn is maintained in the tensioned condition. The unwinding is conducted under sufiicient tension (about 0.1 g./denier) so that'the yarn is stretched straight. The yarns are then immersed for 30 seconds in 60 C. water containing a small quantity of a wetting agent.

The wetted strands are suspended from a hook and weighted while in the wet condition to produce a stress of about 0.2 g./denier, so that the suspended strands are completely smooth. After remaining under this tension for one minute, the lengths of the five strands (X to X are measured. The weights are then removed, and

the strands are dried While hanging freely suspended without any weights at 50-60 C. When the strands are dry they are weighted to provide a stress of 0.02 g./ denier, and after one minute their Weighted lengths (Y to Y are measured.

The elastic extension is then calculated according to the following equation:

Elastic Extension: 100- The yarns of this invention possess a high elastic extension. Generally these yarns have an elastic extension on the order of about and above and frequently on the order of about and above.

The following examples are given to illustrate preferred embodiments of the invention as it is now preferred to practice it. It will be understood that these examples are illustrative, and the invention is not to be considered as restricted thereto except as indicated in the appended claims.

EXAMPLE I A 65-denier polyhexamethylene-adipamide (nylon 66) multifilament yarn consisting of four individual filaments with a titer of 10.8 denier each and 17 individual filaments with a titer of about 3.1 denier each are temporarily high-twisted at 3100 turns per meter by means of a falsetwisting machine and heated in the highly-twisted state at 235 for 0.4 second.

A second identical yarn is crimped in the same manner, but the false twist is imparted in the opposite direction. The two yarns which have been false-twisted in opposite twist direction are then ply-twisted together at the rate of 270 turns per meter in the .9 direction to produce the finished yarn.

The yarn so obtained according to this invention exhibits an elastic extension of 33.8%.

- For comparison purposes, a 70-denier nylon 66 yarn composed of 17 individual filaments having a titer of about 4.16 denier each, is temporarily high-twisted at 3100 turns per meter by means of a false twisting device and heated at 235 C. for approximately 0.4 second in the highly-twisted configuration.

A second yarn having the same composition is crimped by false-twisting as described above, but in the opposite direction. The two yarns are then ply-twisted together at 270 turns per meter in the s direction.

The ply-twisted yarn composed of two 23-filament yarns obtained outside this invention has elastic extension of 21% EXAMPLE II A 70-denier nylon 66 multifilament yarn consisting of two individual filaments with a titer of 15 denier each and 13 individual filaments with a titer of about 3 denier each is temporarily high-twisted at 3000 turns per meter and heated at 230 C. for approximately 0.5 second by means of hot air.

A second yarn which is identical is treated in the same way, but is temporarily high-twisted in the opposite direction. The two yarns are then ply-twisted at 270 turns per meter. The ply-yarn so obtained has an elastic extension of 32.6%.

EXAMPLE III A 70-denier e aminocaproic acid condensation product (nylon 6) multifilament yarn consisting of two individual filaments with a titer of 10 denier each and 12 individual filaments with a titer of about 4.16 denier each is temporarily high-twisted at 3000 turns per meter and heated in the highly-twisted state at 195 C. for approximately 0.8 second by means of hot air.

A second identical yarn is treated in the same way, except that it is highly-twisted in the opposite direction. The two yarns are then ply-twisted together at 500 turns per meter.

The ply-yarn so obtained possesses a very high elastic extension and an agreeable :soft hand.

EXAMPLE IV A 74-denier polyethyleneglycol-terephthalate multifilament yarn consisting of 3 individual filaments having a titer of 10 denier each and 20 individual filaments having a titer of about 2.5 denier each is temporarily hightwisted on a false-twisting device at 3100 turns per meter and heated at 235 C. for approximately one second in the highly-twisted state.

A second identical yam is treated in the same manner, but it is temporarily high-twisted in the opposite direction. The two yarns so obtained are ply-twisted in opposite directions at 60 turns per meter.

The ply-yam so obtained has a high elastic extension and a soft handle.

EXAMPLE V Two multifilament yarns crimped as in Example I and consisting of 65 denier nlyon 66 are separately wrapped on a ring-spinning machine with a wool roving having a metric number of 2.2. The stretching rate in the wrapping operation is about 30. After wrapping, the wrapped multifilament synthetic yarns are ply-twisted together at turns per meter.

A combination yarn with high elastic extension and good slip proofness of the staple fibers is obtained.

What is claimed is:

1. A process for the production of elastic yarn which comprises crimping a synthetic multifilament yarn having at least one coarse synthetic filament with a titer greater than about 6 denier and a plurality of finer synthetic filaments having a titer less than 6 denier by temporarily high-twisting the multifilament yarn, heat-setting the multifilament yam while highly twisted to render such yarn highly elastic and then releasing the high twist from the heat-set yarn.

2. The process of claim 1 wherein the total titer of the multifilament yarn is from about 30 to about 200 denier.

3. The process of claim 2 wherein there are two or more coarse filaments.

4. The process of claim 3 wherein each of the coarse filaments has a titler of from about 8 to about 20 denier.

5. The process of claim 1 wherein each of the plurality of finer synthetic filaments has a titer of between about two and about five denier.

6. The process of claim 1 wherein the coarse filaments have cross-sectional shapes different from the cross-sectional shapes of the plurality of finer filaments.

7. The process of claim 6 wherein the coarse filaments have a trilobal cross-section.

8. The process of claim 6 wherein at least one coarse filament is hollow.

9. The process of claim 1 wherein the highly elastic yarn is subsequently combined with at least one other yarn.

10. The process of claim 9 wherein the highly elastic yarn is wrapped with staple fibers.

11. The process of claim 10 where-in the wrapped highly elastic yarn is further ply-twisted with a second similarly prepared wrapped highly elastic yarn.

12. The process of claim 9 wherein the other yarn component is a similar highly elastic yarn.

13. A highly elastic crimped synthetic multifilament yarn comprising at least one coarse synthetic individual filament with a titer greater than about 6 denier and a plurality of individual synthetic filaments with a titer less than 6 denier, said yarn having good elastic extensron.

14. The yarn of claim 13 with a total titer in the range of from about 30 to about 200 denier.

15. The yarn of claim 13 having two or more coarse filaments.

16. The yarn of claim 15 wherein each of the coarse filaments has a titer of from about 8 to about denier.

17. The yal'n of claim 13 wherein each of the plurality of the finer synthetic filaments has a titer between about two and about five denier.

18. The yarn of claim 13 wherein the coarse filaments have cross-sectional shapes ditterent from the cross-sectional shapes of the plurality of the finer filaments.

19. The yarn of claim 18 wherein the coarse filaments have a trilobal shape.

20. The yarn of claim 18 wherein at least one coarse filament is hollow.

21. The yarn of claim 13 combined with at least one other yarn.

22. The yarn of claim 13 wherein the highly elastic yarn is wrapped with staple fibers.

23. A ply yarn comprising two crimped synthetic multifilament yarn components, each component comprising at least one individual synthetic filament with a titer greater than about 6 denier and a plurality of individual synthetic filaments having a titer less than 6 denier, one component having its twist in the opposite direction to the other component.

24. The yarn of claim 23 wherein both components are staple fiber-wrapped.

References Cited UNITED STATES PATENTS 2,203,721 6/1940 Dingley et al. 57-157 2,777,310 1/ 1957 Comer. 2,890,567 6/1959 Taylor et al 57140 2,991,615 7/1961 Stanton 57144 3,115,745 12/1963 Lathem et al. 57140 3,220,173 11/1965 Pitzl 57140 3,169,363 2/1965 Martin 57l52 3,306,081 2/1967 Miles et a1 57l52 X 2,904,953 9/1959 Groombridge et al.

57157 XR 2,936,569 5/1960 Mull 57157 XR 3,011,302 12/1961 Rupprecht 57l52 3,162,995 12/ 1964 Comer et al. 57157 3,196,602 7/1965 Jenkins et al. 57-157 3,309,863 3/1967 Hermes 57163 FRANK J. COHEN, Primary Examiner.

DONALD WATKINS, Assistant Examiner.