US3091913A - Variable denier composite yarn - Google Patents

Description

June 4, 1963 c. HELD, JR 3,091,913

VARIABLE DENIER COMPOSITE YARN Original Filed March 15, 1959 FREDERICK CROMWELL FIELD, JR.

BY @MW ATTORNEY 13 Claims. c1. si -rte This invention is concerned with textile yarns and more specifically with multiple component textile yarns. This is a division of my copending application Serial No. 799,128, filed March 13, 1959.

Textile yarns from both natural and synthetic fibers have been developed with a wide variety of physical structures. While there are many different purposes and goals which these different physical structures seek to achieve, a large number are designed to provide fabrics with attractive appearance and pleasing hand. One yarn structure used in this way is known as slub or thick-and-thin yarn, a structure found in linen fabrics, particularly those of heavier textures. In silk fabrics the effect is called Dupioni and is found in mens and womens suits and dress fabrics.

In the manufacture of synthetic textiles, uneven denier effect has been produced in a number of Ways. Some of these involve varying the rate at which filaments are formed or the rate at which filament-forming material is supplied during the process of filament formation, irregular quenching or coagulating treatments of the filaments during formation and, in the case of fibers and filaments which are drawn, variable drawing techniques. It is also possible to prepare variable denier yarns by specialized spinning or yarn forming processes from filaments which are in themselves uniform in denier. Such processes, however, generally require elaborate and expensive equipment from which variable denier yarn is produced only at a slow rate. In many cases, when special yarn spinning processes are involved, variations in denier are achieved by regular or irregular spacing of multiple wraps of one yarn component, called the elfeot yarn, upon a base of a second yarn component referred to as the core yarn. Such two-component yarn systems offer the possibility of very large variations in denier along the length of the yarn. These denier variations produce pleasing eflects in fabrics of such yarns. However, because these yarns must be produced by an elaborate Winding technique, the equipment necessary is very intricate and variation from one yarn type to another can be achieved only with time-consuming changes in the equipment. Furthermore, since components of these yarns are merely wrapped one about the other, the components tend to become separated with a resulting loss of the desired effect.

It is an object of this invention to provide a novel multicomponent variable-denier textile yarn in which the several yarn components are interent-angled with one another. Another object is to provide a multi-component textile yarn of substantially uniform long range denier, in which the various components are inter-entangled, but possess in the structure difierent elongation characteristics so that they are suitable for preparation of variabledenier yarns of the type described. It is a further object of this invention to provide a process for the preparation of multicomponent variable denier textile yarns in which the relative quantities of core and effect yarns can be varied readily and simply. A still further object of this invention is to provide a process for the production of multicomponent variable denier textile yarns in which the several components are interentangled one with another. Other objects will become apparent from the description which follows.

FIGURE 1 is an enlarged view of a composite textured yarn of at least two yarn components passed through a yarn-bulking jet simultaneously and at different rates of overfeed;

FIGURE 2 is an enlarged View of a multifilament yarn after treatment by a yarn-bulking fluid jet;

FIGURES 3 and 4 are microscopic views of two composite yarns after treatment by the apparatus of FIG URE 5;

FIGURE 5 is :a schematic drawing of suitable apparatus for carrying out the process according to: the present invention; and

FIGURE 6 is a side elevational view of the wrapping jet device 15 of FIGURE 5 taken at line 66.

According to this invention there is provided a multifilament yarn containing at least two groups of filaments, one group comprising a plurality of filaments having a substantially higher extensibility factor than the remaining filaments, the filaments in one group being interentangled with the filaments of another group and be ing distributed in variable concentrations along the length of the other. At least one of these groups of filaments is a synthetic organic fiber. These yarns are prepared by feeding through a yarn-bulking jet of fluid (such as those described in U.S. 2,783,609 to Breen) simultaneously and at difie-ren-t rates of overfeed, two or more yarn components, whereby the individual filaments of the component yarns become interentangled to produce a product as shown in FIGURE 1 wherein filaments of yarn 3 are entangled with filaments of yarn 4. Notmally, the yarn with the lowest rate of overfeed becomes a core yarn 3 and yarn components with higher rates of overfeed become effect yarns 4, giving a composite textured yarn of at least two components with the filaments of each interentangled with one another and with the components possessing substantially different extensibility factors. By the term extensibility factor is meant the sum of the elongation-at-break of a filament in the yarn and the increase in length which the filament undergoes when it is straightened completely Without stretching.

While the textured yarns resulting from the process as described can be used in this state without further processing, it is desirable further to process these yarns to obtain the even more unusual and attractive Variable denier yarns. :In a preferred embodiment, yarns, as described above, are treated to produce a multifilament yarn having a filamentary core component intimately interentangled with a plurality of distinct bundles of discontinuous filaments, the latter being distributed in variable quantities and lengths at random intervals along the yarn and completely surrounding the core component. The filamentary core component and bundles may be either spun or continuous filaments. It is preferred for increased strength and stability of the final product that the core component have a substantially linear configuration or may be in the form of a bulky yarn depending upon processing conditions in the fluid jet, such as overfeed, jet apparatus design, temperature, fluid velocity, etc. The discontinuous filament bundles are preferably derived from a bulky type yarn, for increased strength. Greater interentanglernent of the core component and discontinuous filament bundles is accomplished when the bundles are derived from spun staple fibers. These preferred yarns are prepared by passing at least two yarns through a fluid jet as described above followed by applying suflicient tension to the composite structure thus produced to break the filaments of the component having the lowest extensibility factor. The composite structure may be stretched, if desired, until the filaments with the highest extensibility factor are at their original length Patented June 4, less but not sufiiciently to break these filaments nor to separate the components completely one from another. The yarn-bulking fiuid jet device referred to is preferably of the type described in US. Patents 2,783,609 and 2,852,- 906, to A. L. Breen, which is operated by passing a yarn into a turbulent fluid stream whereby the individual filamerits of the yarn are caused to be convoluted, bulked and intercntangled. Yarns thus produced are bulky yarns characterized by having a plurality of substantially continuous filaments individually convoluted into coils, loops, whorls, and crunodal loops irregularly spaced along the yarn surface, as shown in FIGURE 2.

Regardless of the type filamentary structure from which the bundles are derived, whether continuous or spun yarn, they constitute distinct and separate groups of discontinuous filaments, completely surrounding the core member and sufficiently interentan-gled therewith to provide a stable slub yarn. These bundles, or slubs, are distinct in that they are each composed of a distinct body of discontinuous filaments, though there may be, of course, some contact between individual bundles. The length of these bundles may vary along the length of the core component.

Although the multicomponent yarns of this invention may be, at least in part, bulky yarns, they are quite diflerent from the bulky yarns of the above-mentioned Breen patent. Because of the diiference in the rates of overfeed between the several components of the yarns of this invention, the filaments bunch together and are not distributed uniformly along the length of the yarn. This results in a slub effect caused by variations in denier along the yarn due to the fact that in some regions a greater quantity of material is present than in other regions. The resulting change in over-all denier gives an effect similar to the Dupioni or linen type yarns and is most apparent and attractive when the yarn is woven or otherwise processed into a fabric.

In the simplest preferred embodiment of this invention, the composite yarn is made up of two components, the initial core yarn (prior to breaking) having a substantially lower extensibility factor (preferably less than about /2 that of the initial effect yarn) because the latter is overfed to the fluid jet at a substantially higher ratepreferably at least twice as fast (twice the unit length per unit time). When this composite yarn is stretched, as already described, the core yarn will break randomly and will form along the threadline a series of slubs giving the composite yarn a variable denier. The initial elfect yarn which during the processing is fed into the bulking jet at a much higher rate than the core yarn has a high exten 'bility factor, thereby permitting it to remain unbroken during the stretching process which breaks the initial core component. Thus, a reversal of function of the two components occurs, the initial core component becoming the eifect component of the final composite yarn while the initial effect component becomes the core component of the final yarn product. During the stretching-breaking step broken sections retract while the unbroken members are elongated and the short bulked lengths become knotted even more firmly into the composite structure. This bunching efiect occurs at random intervals along the length of the composite yarn and the frequency of slub sections can be adjusted and controlled by variation of relative rates of overfeed and denier of components and conditions of breaking. *In addition, bulking conditions such as total speed, air pressure, and jet adjustment as described in the above-mentioned Breen patent can be varied to influence the bulkiness, the degree of entanglement, and the degree of loopiness and thus the eventual physical properties and appearance of the composite yarn.

An alternate procedure for providing the novel product of this invention comprises passing at least two yarn components through a zone of fluid turbulence, at least one of the yarn components having an extensibility factor at least twice that of the remaining yarn. The yarn having the higher extensibility factor is fed through the zone at a rate at least twice that of the lower extensibility factor yarn and at a rate approximately that of the rate of removal of the final product from the zone of fluid turbulence. During treatment in the zone, the lower ex tensibility factor yarn, becomes intimately interentangled with the higher extensibility factor yarn. The tension on the interentangled composite yarn caused by the high rate of withdrawal, as compared to the rate of feed of the low extensibility factor yarn, as well as the extensibility of the yarn causes this yarn to break randomly into distinct bundles of discontinuous filaments, distributed in variable quantities and lengths at random intervals along the higher extensibility factor component and sufficiently interentangled to consolidate the bundles with the higher extensibility factor component, which takes the form of a core member. This core member may be slightly overfed, preferably about l2% for increased entanglement with the slub component.

The bundles, or slubs, may be further consolidated with the core member by any one of many twisting or treating procedures, such as by a downtwister, spinning frame, wrapping jets, such as disclosed in US. applications serial numbers 598,135, filed July 16, 1956, now Patent No. 3,009,309, and 752,451, filed August 1, 1958, now abandoned, chemical treatment, such as sizing, or plasticizing with either heat or solvent. The wrapper jet procedure is preferred in that the slub bundles are more tightly Wrapped completely around the core member. Furthermore, the use of such wrapper jets is not a limiting factor on process speed.

The ratio of windup speed to feed rate of the slub component whereby breaking of this component is efiected depends primarily on the extensibility factor of the particular yarn. The ratio can be lower in cases where the yarn has a very low extensibility factor. In general, a ratio of about 2:1 is satisfactory, while a ratio up to about 50:1 and above may also be used.

A schematic drawing of suitable apparatus for the process of this embodiment of the invention is shown in FIGURE 5. Core component 8 and slub component 9 are fed off bobbins 10 and 11, respectively into a fluid bulkingjet 12 of the Breen type described above. Feed rolls 20 and 21 may be utilized as shown to feed the yarn components to the jet. The composite yarn structure is then fed into the passageway 14 (see view of FIGURE 6, taken along line 6-6 of FIGURE 5) of wrapping jet 15 where it is subjected to a blast of fluid entering through orifice 16, which enters passageway 14 tangentially and then the yarn is wound up on roll 17. Alternatively, at high speed operation, a snubber bar 18 may be placed between the two jets, to prevent excessive backing-up of the twist imparted in the Wrapping jet into the fluid bulking jet. Tensioner 19 may also be provided to control more definitely the tension on core component 8.

Microscopic views of two such composite yarns are shown in FIGS. 3 and 4, which show bundles 5 and 5' wrapped completely around core members 6 and 6. The twisted areas generally obscure the entanglement produced but is clearly indicated at 7.

Additional suitable fluid jets include those described in US. applications Serial Numbers 781,549, filed December 19, 1958, now Patent No. 3,005,251, 604,564, filed August 16, 1956, now Patent No. 2,958,112, 698,103 filed November 22, 1957, and US. Patent 2,852,906. Those jets having a forwarding effect on the yarn are particularly desirable. Many of these fluid jets, with proper modification as to design and/or fluid used, are suit-able as Wrapper jets, it being essential only that the wrapper jet further consolidates the multi-component structure.

By the practice of this invention it is possible to achieve a wide range of variable denier composite yarns of the Dupioni type. Size and character of the individual slubs,

frequency of occurrence of slubs, variation of maximum and denier, and the amount of residual bulkiness can be easily controlled and regulated.

Various combinations of relative fluid pressures between the various jet elements may be used to produce variation in the size and length of the discontinuous filament bundles. Similar eifects may be achieved by varying the rates of feed of the various components and the tension on the core component during the treating process.

Diiferent rates of overfeed result in varying composite yarn structures and the diflerent operating conditions of the bulking fluid jet and the wrapping jet provide diflerent elfects because of the varying extent of interentanglement and interpenetration of the yarn components of the structure. Jet air pressure may be fluctuated during the formation of the composite structure to produce variations in degree of entanglement or during the wrapping to produce variations in degree of wrapping. If intermittent periods of high air pressure are used in processing together a relatively brittle filament yarn (e.g., glass filaments or some cellulose acetate filaments) and a relatively tough yarn, the brittle component can be disintegrated and removed from the composite structure at intervals. This method of operation leads to a slub yarn containing discontinuous filaments, without employing a stretching-breaking process. Similar effects can be obtained by using, in place of the above-mentioned brittle filaments, a loosely-constructed staple yarn of short fiber lengths, which can be broken under high air pressure operation of the jet.

Short range denier variations in the intermediate yarn product (prior to any breaking) of this invention are obtained simply by passing the yarns simultaneously through a fluid jet and then stretching without breaking. Concentrations of effect yarns along the composite yarn length can be accentuated by introducing a pinching or dragging device in the yarn path or by interrupting momentarily the flow of one or more of the yarn components with higher rates of overfeed. Thus, while over a long length, delivery of this component may be constant, there can be short range fluctuations of several hundred percent, and the composite yarn denier will vary correspondingly. Interruption of effect yarn flow can be controlled by such devices as cams, rocker-bar arms, and the like.

Any combination of two, three, or more different synthetic fibers may be used as the component members of the composite yarn. Also, a single type fiber in two or more different yarn counts or pre-dyed and undyed yarns of the same or diiferent polymers may be used in making up the composite structure. It is also possible, as discussed above, although less preferred, to employ as at least one component, either as a core or slub component, a synthetic staple yarn or naturally occurring fiber such as silk, linen, or even under certain circumstances cotton or woolen yarns. The desired eifects are not so readily obtained with these latter combinations and continuous filament synthetic fibers with predetermined breaking elongation characteristics are preferred. Fibers which are already discontinuous respond less readily to the basic process already described, and there is available less flexibility in the range of products which result, but the fine hand of these products makes them highly desirable.

Preferably desirable combinations of components useful in this invention include nylon with rayon; nylon with acrylic fibers; polyethylene terephthalate fiber with rayon, acetate or acrylic fibers; acrylic fibers with rayon or me tate; nylon with silk or glass fibers and similar combinations, which on the basis of the foregoing descriptions, will be apparent to those skilled in the art.

This process may be coupled with other textile treating procedures, such as twisting, drawing or winding.

The following examples illustrate specific embodiments of the invention.

6 Example I Two continuous-filament textile yarns are fed simultaneously to a yarn-bulking jet of the type described in Us. patent application S.N. 604,564, now Patent No. 2,958,112, using air as bulking fluid at sonic velocity. One yarn, a 200 denier, 64 filament blue-dyed cellulose acetate of zero twist, is fed to the jet at 29 /2 y.pm., while the other, a 200 denier, 34 filament nylon yarn with /2 turn of Z twist per inch is fed at 57 y.p.m. The yarns are bulked in the jet and the composite structure wound up at 28 y.p.m. The composite structure is rewound on a downtwister with 7 turns of Z twist at 30 y.p.m. In the rewinding process, tension caused by the downtwister breaks the acetate filaments and elongates the nylon filaments, removing all crunodal loops from the nylon. The result is a slub-type yarn with a smooth nylon core, random lengths of discontinuous bulked acetate filaments being intimately interentangled with the nylon core filaments. This composite slub yarn is woven into a plain- Weave fabric With :a warp of 7034 Dacron polyester fiber yarn to give a material with a pronounced slub effect in which only the slubs are blue.

Example 11 The composite bulked yarn is wound up at 30 y.p.m. and then broken as before on a downtwister. Both of the acetate yarns break, but with different frequency, giving a very random slub eflect.

Example III The general procedure of Example I is followed except that in place of acetate yarn an undyed zero-twist yarn of continuous filament polyethylene terephthalate is used. Feed rates to the jet are as described in Example I, except that the feed rate of the nylon component is varied at irregular intervals with a randomly operated rocker arm. The bulky composite yarn is rewound with low tension and the polyethylene terephthalate does not break during the process. The resulting yarn product contains continuous strands of both nylon and polyethylene terephthalate with the nylon as an eifect component forming slubs with random distribution along the polyethylene terephthalate core component. These slubs are formed during the winding operation because of the excess of the nylon yarn. This yarn is suitable for fabrics containing any type of variable denier bou-cl or ratin. The same procedure is followed using the intermittent tensione-r described in US. application Serial Number 610,546, now Patent No. 2,931,090, filed September 18, 1956, instead of the rocker arm, and similar results are obtained.

Example IV As in Example I, two textile yarns are employed as follows:

Yarn Count Feed Rate,

y.p.m.

Red-dyed acetate 150-40-2 Z Undyed nylon 7034-% 2 40 breaks up completely and is blown away from the yarn threadline. At lower pressure, the acetate is entangled with the nylon and remains at a slub-component.

Example V The procedure of Example I is followed, except that in place of the acetate yarn, a rayon yarn, 100 denier, 34 filaments, 2% Z twist, is used, and in place of the nylon yarn, a polyethylene terephthalate yarn of 70 denier, 34 filaments, /2 Z-twist is used. After breakage, the rayon yarn becomes a slub component on the core of polyester filament.

Example VI The procedure of Example I is followed, except that the nylon yarn is replaced with an acrylic continuous filament yarn, 200800.3 2.

Example VII Two continuous-filament textile yarns are fed simul taneously into an air jet as described in Example 1. One yarn, a 75 denier, 24 filament, zero twist navy blue acetate yarn is fed at a rate of 35.5 y.p.m., the other yarn, a 70 denier, 34 filament, Z-twist nylon, yarn, at a rate of about 425 y.p.m. These yarns are bulked in the air jet at an air pressure of 35 p.s.i.g.

The resulting bulked yarn is characterized in that the nylon yarn is intimately interentangled with the acetate yarn, the nylon yarn constituting a core element. As the bulked yarn is removed from the air jet at a. wind-up speed of 425 y.p.m., the acetate yarn breaks randomly along its length and is wrapped slightly around the nylon yarn, which has been elongated during its removal from the air jet.

The resulting yarn is then passed into the /8 inch passageway of a wrapping jet. Air is forced into this orifice through a A inch orifice at a rate of 40 p.s.i.g., tangentially of the let orifice. Upon close examination, this yarn shows a plurality of distinct bundles of discontinuous acetate filaments wrapped completely around the nylon yarn. Under a ten power microscope, the discontinuous acetate slubs are seen to be intimately interentangled with the nylon yarn core. Some of the individual slubs encircle the nylon yarn core in both 8 and Z directions, one twist being superimposed over the other.

After inspection, the composite slub yarn is woven into a plain weave fabric with a warp of 70-34 count poly ethylene terephthalate fiber yarn to give a decorative material with a pronounced effect produced by the blue acetate slubs.

Example VIII The procedure of Example VII is repeated except that a 55 denier, l8 filament, zero twist bright acetate yarn is substituted for the navy blue acetate yarn and a' 40 denier and 13 filament, /2 Z-twist nylon yarn is substituted for the nylon yarn. Thefeed rate of the acetate component is 27 y.p.m., the rate of the nylon component and wind-up speed being the same. The air jet pressure is 55 p.s.i.g., the wrapping jet pressure being the same. Both visual and microscopic examination indicate a similar slub yarn is obtained. When woven into. a plain weave fabric with the same polyester yarn, a decorative fabric with a pronounced slub effect is obtained.

Example IX The procedure of Example VII is repeated except that 40 denier, 20 filament, 2.5 S-twist dull rayon yarn is substituted for-the acetateyarn and 70 denier, 34 filament,

A2 Z-twist nylon is used; The feed rate of the rayon com-- ponent is 52.5 y.p.m., the feed rate of the nylon composlubs are distinct bundles of discontinuous filaments wrapped completely around the nylon yarn core. Micro- 8 scopic examination as before shows an intimate interentanglement between the slubs and the core. The right and left twist phenomenon is again noticed.

A plain-weave fabric is prepared as before to provide a decorative materialshowing the slub effect.

Example X r The general procedure of Example VII is repeated, except that a 60/1 blend of polyethylene terephthalateacrylic fiber spun yarn (18 Z twist) is substituted for the acetate yarn and 70 denier, 54 filament zero twist polyethylene terephthalate yarn is substituted for the nylon yarn. The feed rate of the spun yarn component is 8 y.p.m., the feed rate of the continuous yarn being 425 y.p.m. The air jet and wrapping jet pressures are 40 p.s.i. and 35 p.s.i., respectively. The wind-up rate of the bulky yarn from the air yet is 56 y.p.m. Visual observation indicates the spunyarn component broken into several distinct filament bundles wrapped completely around the polyester continuous filament core. Free ends are particularly noticeable in this embodiment. Microscopic examination shows very clearly the entanglement of the slub and core components, as well as the free ends. A fabric is woven as before to provide a decorative material of particularly good hand.

' Example XI The general procedure of Example VII is repeated except that denier, 36 filament, Zero twist bright acetate is substituted for the navy blue acetate and 210 denier, 34 filament, Z twist nylon is used. The feed rates of the acetate component and nylon component are 27 and 425 y.p.m., respectively. The wind-up speed is the same, the air jet and wrapping jet air pressures being 54 and 44 p.s.i., respectively. Both visual and microscopic examination indicate a similar slub yarn is obtained, although the slubs are just slightly shorter in length than those produced in Example VII. A similar woven fabric is obtained.

Example XII The general procedure of Example VII is repeated except that 40 denier, 2O filament, 2.5 2 twist dull rayon yarn is substituted for the acetate yarn and 70'denier, 34 filament, zero twist polyethylene terephthalate yarn is substituted for the nylon yarn. The feed rates of the rayon and polyester yarns are 27 and 425 y.p.m., re spectively. The wind-up speed is the same, the air jet and wrapping jet air pressures being 15 and 30 p.s.i., respectively. Both visual and microscopic examination indicate a similar slub yarn is obtained, except that the slubs are slightly shorter as in Example XI. A similar woven fabric is obtained.

Additional suitable fluids for the jet treatments include hot air, steam and other heated fluids.

I claim:

1. A multifilament yarn containing at least two groups of highly bulked filaments, one group comprising a plurality of filaments having an extensibility factor at least twice that of the remaining filaments, thefilaments having the higher extensibility factor being intimately randomly variably interentangled with the remaining filaments and being distributed in variable concentrations. randomly along the length of yarn.

2. The yarn of claim 1 in which the filaments having the higher extensibility factor are nylon.

3. The yarn of claim 1 in which the filaments having the higher extensibility factor are polyester filaments.

4. The yarn of claim 1 in which the filaments having the lower extensibility factor are cellulose acetate.

5. A multifilament yarn having variable denier and characterized by a plurality of highly bulked filaments intimately randomly variably interentangled with a plurality of highly bulked discontinuous filamentary bundles, the latter occurring in varying concentrations at random intervals along the length of the yarn.

6. The multifilament yarn of claim 5 wherein the filaments are continuous.

7. The yarn of claim 6 in which the continuous filaments are nylon.

8. The yarn of claim 6 in which the continuous filaments are polyester filaments.

9. The yarn of claim 5 in which the discontinuous filamentary bundles are cellulose acetate.

10. A multifilament yarn having variable denier and characterized by a highly bulked continuous filamentary core component intimately randomly variably interentangled with a plurality of randomly spaced distinct bundles of discontinuous highly bulked filaments.

11. A multifilament yarn having variable denier and characterized by a continuous highly bulked filamentary core component intimately randomly variably interentangled with a plurality of distinct bundles of discontinuous highly bulked filaments, said bundles occurring in varying concentration at random intervals along the length of the yarn.

12. A multifilament yarn having variable denier and characterized by a continuous highly bulked filamentary core component intimately randomly variably interen- 10 tangled with a plurality of distinct bundles of discontinuous highly bulked filaments, said bundles occurring in varying concentration at random intervals along the length of the yarn and having portions of said discontinuous filaments completely surrounding said core component.

13. A multifilament yarn having a continuous highly bulked filamentary core component completely surrounded at random intervals along its length by portions of distinct highly bulked filamentary bundle components, said bundle components also being sufiicient-ly intimately randomly variably interentangled with said core component to provide a consolidated composite structure.

References Cited in the file of this patent UNITED STATES PATENTS 2,745,240 Brant May 15, 1956 2,869,967 Breen Jan. 20, 1959 3,007,298 Williams Nov. 7, 1961 FOREIGN PATENTS 1,178,980 France Dec. 15, 1958

Claims (1)

1. A MULTIFILAMENT YARN CONTAINING AT LEAST TWO GROUPS OF HIGHLY BULKED FILAMENTS, ONE GROUP COMPRISING A PLURALITY OF FILAMENTS HAVING AN EXTENSIBILITY FACTOR AT LEAST TWICE THAT OF THE REMAINING FILAMENTS, THE FILAMENTS HAVING THE HIGHER EXTENSIBILITY FACTOR BEING INTIMATELY RANDOMLY VARIABLY INTERENTANGLED WITH THE REMAINING FILAMENTS AND BEING DISTRIBUTED IN VARIABLE CONCENTRATIONS RANDOMLY ALONG THE LENGTH OF YARN.

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