US3271943A

US3271943A - Process for stabilizing bulked yarns and product thereof

Info

Publication number: US3271943A
Application number: US334435A
Authority: US
Inventors: Jr Ebenezer David Williams
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1963-12-30
Filing date: 1963-12-30
Publication date: 1966-09-13
Anticipated expiration: 1983-09-13
Also published as: DE1435640B2; DE1435640A1; BE681756A; LU47665A1; DE1435640C3

Description

Sept. 13, 1966 D. WILLIAMS. JR 3,271,943

PROCESS FOR STABILIZING BULKED mans AND PRODUCT THEREOF Filed Dec. 30, 1963 4 Sheets-Sheet 1 iVV+++ INVENTOR EBENEZER DAVID WILLIAMS, JR

ATTORNEY p 1966 E. D. WILLIAMS, JR 3,271,943

PROCESS FOR STABILIZING BULKED YARNS AND PRODUCT THEREOF Filed Dec. 30, 1963 4 Sheets-Sheet 2 FIG.4

auca-| ELOIIGATION. In AT .027 gpd. LOADING N U I RELATIVE HUIIIDITY; I.

IOISTIIRE C(IIITEIIT 0F YARN II INVENTOR EBENEZER DAVID WILLIAMS, JR.

BY 4m ATTORNEY p 1966 E. o. WILLIAMS, JR 3,271,943

PROCESS FOR STABILIZING BULKED YARNS AND PRODUCT THEREOF Filed D60. 30, 1963 4 Sheets-Sheet 5 FIG.6

YARN IODULUS. 90d. m u 4:- 0v 0: w

RELATIVE HUMIDITY,

FIG.7

I 50 80 RELATIVE HUMIDITY, In

INVENTOR EBENEZER DAVID WILLIAMS,JR

BY J 3 ATTORNEY Sept. 13, 1966 E. o. WILLIAMS, JR 3, 3

PROCESS FOR STABILIZING BULKED YARNS AND PRODUCT THEREOF Filed Dec. 30. 1963 4 sheets-sheet 4 L.-- it FRICTION INDEX T T AT 85 'l- RELATIVE HUMIDITY I I I I I I 0.1 0.2 0.3 0.4 0.5 0.6 0.? 0.8 0.9 L0

FIIIISII 0N YARN, I.

FIG.9

INVENTOR ATTORNEY EBENEZER DAVID WILLIAMS. JR.

United States Patent 3,271,943 PROCESS FOR STABlLlZlNG BULKED YARNS AND PRODUCT THEREOF Ebenezer David Williams, Jr., Seaford, DcL, assignor to I. du Pont de Ncmours and Company, Wilmington, Dcl., a corporation of Delaware Filed Dec. 30, 1963, Ser. No. 334,435 8 Claims. (Cl. 57-.140)

This invention relates to a method for treating a bundle of filaments such as a yarn or thread and to the products so obtained. More particularly, the invention relates to bulky yarns composed of individually crimped filaments and a treatment of such yarns to improve their physical characteristics.

Artificial fibers are normally produced most easily in the form of yarns composed of continuous filaments. These continuous-filament yarns are very strong because of the absence of loose ends that are unable to transmit imposed stresses. Their extreme uniformity and lack of discontinuity, however, make conventional continuousfilament yarns much more dense than yarns made from staple fibers. On the other hand the production of yarns from staple fibers is time-consuming and requires a complex series of operations to crimp the fibers, align the fibers into an elongated bundle and then draw the bundle to successively smaller diameters. Nevertheless the final spinning operation, which involves a high degree of twist, finally binds these discontinuous fibers together in the form of a coherent yarn having a considerably increased bulk. The occluded air spaces give them a lightness, covering power, and warmth-giving bulk not normally poss ble with continuous-filament yarns. Thus, to get staple fibers that can be processed on conventional woolor cotton-spinning equipment, it has been the practice to cut continuous-filament yarn such as rayon, acetate, nylon, as well as the polyacrylic and polyester fibers into short lengths for spinning into staple yarn.

Developments in the textile industry have provided useful routes for improving the bullk and covering power and recoverable elongation of continuous-filament yarns without resorting to the staple-spinning systems of the prior art. A well-known process for making stretchyarn involves the steps of twisting, heat-setting and then bucktwisting to a low final twist level; Another yarn of improved bulk is prepared commercially by the steps of twisting, heat-setting and backtwisting on-the-run using a false-twisting apparatus. This end product can he further modified by hot relaxing to improved the bulk and handle. stutter-box technique wherein the yarn is steamed to heatset it while it is in a compressed state in the stulfer box. Thus by passing a running yarn into the nip of intermeshing gears, a crimpy yarn is obtained. Still another bulky yarn is produced by running a continuous-filament I yarn over a heated blade. More recently methods have been developed in which crimp is imparted to continuousfilament yarns by subjecting them to the action of a turbulent tluid stream while in a plasticized condition and thereafter setting the filaments in the crimped configuration.

The described prior art yarns are not only bulky in a relaxed condition but are also quite extensible when subjected to light loads. Although a high degree of extensibility is of considerable benefit in the manufacture of so-called stretch fabrics, a low degree of extensibility is desired for other textile articles such as firm fiat-woven fabrics, heavy warp-knit structures and tufted carpets. In the latter instance, the very highly bulked yarns are not only difiieult to process into finished articles, but also the finished goods may frequently be deficient in terms of quality and uniformity. It has heretofore been recognized that the performance of these highly crimped Bulk yarn is also prepared by the well-known 3,?7l,$l lli Patented Sept. 13, 1966 yarns for such purposes could be markedly improved if the stretch properties were modified so that the extensibility is reduced While maintaining the voluminous nature. A known method of accomplishing this is to extend the crimped yarns and pass them through a heated zone while under an accurately controlled degree of relaxation, and set the yarn in the desired condition. While normally satisfactory, such thermal techniques suffer from the disadvantage that they require expensive heating devices in addition to complicated temperature regulating devices.

Another deficiency in the prior art yarns relates to the wide variations commonly experienced in frictional characteristics. These tend to give variations in the feeding of the bulked yarn through the guides and needles of carpet-tutting machinery, for example, and also to detract from the uniformity of the finished carpeting.

A principal object of this invention, therefore, is to provide an improved bulky yarn which retains a selfcriruping tendency and possesses a desirable combination of bulk, stretch and frictional characteristics. Another object is to provide a novel method of producing such improved bulky yarns. An additional object is a method for treating a bulky yarn to regulate its crimping tendencies over a wide range of commercial processing conditions. Another object is to provide a method for producing a bulky yarn with a relatively low self-crimping 1 tendency and low frictional characteristics while substantially retaining the bulkiness of the yarn. The invention also provides a simple and highlyieflicient method for regulating the bulk and stretch properties of a bulky yarn.

In accordance with the present invention a method is provided for reducing the extensibility of a bulky yarn composed of crimpcd continuous filaments of a synthetic polymer. The method comprises applying liquid water to a running length of the yarn at normal temperatures while the yarn is under a tension of at least 0.02 gram per denier and winding the water-treated yarn under tension into a package, the quantity of water applied to the yarn being at least of the equilibrium content of the filaments at relative humidity as measured at 20 C. In preferred embodiments of the invention the bulky yarn has a friction index less than about 3.0, and the polymer is a polyamide, especially poly(hcxamethylene adipamidc). The yarn treatment is advantagcously carried out as a continuous method which includcs the steps of spinning the filaments, collecting the filaments in the form of a multifilameut yari, bulking and relaxing the filaments of the yarn, subsequently effeeling the water/tcnsioning treatment and winding the bulky yarn under tension into a package. For purposes of this invention, the yarn is preferably bulked by [coding continuously through a plasticiziug: lluid stream to yield a highly crimpcd yurnwhich is then cooled and set while in a relaxed condition.

The resultant yarn product has a relatively low crimping tendency, low extensibility and low frictional characteristics which favor the performance of the yarn over the wide range of humiditics encountered in commercial processing.

The invention, its advantages and the manner of conducting it will be more clearly understood by referring to the drawings and disclosure which follow.

FIGURE 1 is a longitudinal view of a bulky continuous multi-filament yarn produced by the invention.

FIGURE 2 is a diagrammatic perspective view of apparatus suitable for treating a bulked yarn in accordance with the present invention.

FIGURE 3 is a schematic perspective view of apparatus for combining the process of this invention with steps of mclt spinning, drawing, bulking and relaxing to provide an integrated continuous manufacturing process for obtaining improved bulky continuous filament yarns.

FIGURE 4 shows graphically the percentage elongation of the product of the invention when subjected to low tensile loading under various humidity conditions.

FIGURE 5 shows graphically the relationship between the elongation of the product of the invention under low tensile loading and the moisture content attained during its processing.

FIGURE 6 shows graphically the relationship between the ini ial tensile modulus of the product of the invention and the relative humidity of the ambient air.

FIGURE 7 shows graphically the effect of relative humidity on retraction, a measure of crimping tendency.

FIGURE 8 shows graphically the relationship between the frictional characteristics of the product of this invention and its finish content.

FIGURE 9 is a schematic diagram of an apparatus for measuring frictional characteristics.

, Referring now to the drawings, FIGURE 1 illustrates the bulky yarn of this invention. It shows a yarn bundle composed of a plurality of individual continuous filameats, each of which has a wavy three-dimensional crimp. The configuration of the individual filaments prevents them from packing into a'closely nested arrangement in the yarn bundle, even when under considerable tension. This property is particularly useful in increasing the bulk and cover of tightly woven, knit or tuftedpile textile articles. The tendency of the crimped filaments to intermingle or interentangle lends a slight coherence to the yarn bundle which may be increased by known pneumatic interlacing or mechanical twisting processes. 7

in its preferred embodiment, the yarn is composed of synthetic organic filaments which have'been initially crimped by a plasticizing fluid-stream of compressible fluid as in British Patent 905,895 or by conveying a yarn in a fluid stream against a surface to mechanically deform it while in a plastic condition as in British Patent 861,108. The invention may also be applied to certain yarns which have been treated in the known stutter-box, in the falsetwist heat-setting process or other modes of crimping. As will be seen in the subsequent description, the preferred crimped product is a bulky nylon continuous filament yarn which is packaged under at least 0.02 g.p.d. tension with at least 4% by weight moisture and with a friction index less than 3.0. The crimping tendency and other physical characteristics of the yarn are maintained at desired levels so as to render the yarn particularly us ful for fabrication into textile products.

FIGURE 2 illustrates schematically the process of this invention using a simple form of apparatus. A bulky feed yarn 20 containing a predetermined quantity of a lubricating finish is advanced at a desired speed by passage between feed rolls 21 and 22 and passes through a spray of liquid water 23 emitting from atomizing nozzle 24 while under tension, whereupon the treated yarn 25 is wound into a package 26. Package 26 is wound on rotatable cylindrical core 27 with a suitable traverse, not shown, and is surface-driven by rotating cylindrical driveroll-28. The relative speeds of the drive roll 28 and feed rolls 21 and 22 are adjusted to attain the required tension in the treated'yarn 25. Alternatively the tension on the treated yarn may be adjusted by the winding torque of package 26.

FIGURE 3 illustrates a process for producing meltspun bulked yarns by the invention. Filaments 30 from spinneret 31, quenched by a cross-flow of cooling air from plenum 32, are converged at guide 33 and passed around a pair of rolls 34. The yarn passes around draw pin 35 and is continuously drawn by Wraps around a pair of rolls 36' moving at higher speed. The drawn yarn then passes over idler roll 37 and into fluid jet 38 in which the yarn is plasticized and treated by a stream of compressible fluid. The bulked yarn leaving the jet is crimp-set on revolving screen-surfaced drum 39 and, while riding on the drum and under no applied tension, is subjected to a spray of lubricating finish 40 issuing from spray nozzle 41. The bulked yarn is then taken from through guide 46 to a package 47 under the required tension. The package is wound on cylindrical core 48 and surface-driven by drive roll 49. 1

After the moisture treated bulky yarn has been wound 7 under tension, the moisture surrounding the filaments may gradually become dissipated into the atmosphere during shipment and handling of the package or during use of the yarn; Notwithstanding such changes in mois turc content, however, the improved properties which characterize the products of the invention, including relative insensitivity to humidity and humidity fluctuations, continue to persist.

To provide a bulky extensible yarn which is relatively insensitive to variations in relative humidity during textile processing, the moisture content of the treated yarn as it is Wrapped under tension must be at least 50% of the equilibrium moisture content of the fibers at relative humidity (at 20 C.). In the case of 66 nylon this is approximately 4 weight percent. For most purposes the yarn in the package should contain no more than about 10% by weight of water. If allowed to'appreciably exceed this amount, water droplets will be thrown from the moving yarn onto the process machinery and furthermore, the wound packages of yarn will be unduly Wet and soggy. i

In accordance with the method of the invention, the water treatment of a running length of bulky yarn under tension is conducted at normal temperatures. It is a sig nificant feature of the invention that the method can be satisfactorily conducted at atmospheric or ambient temperature conditions. Depending upon the geographical location, the manufacturing plant facilities, and other factors, the method will normally be performed at temperatures of 5 to 40 C., most frequently at 15 C. to 35 C. Similarly it is unnecessary to heat or cool the water which is 'used in treating the yarns, the aforementioned temperature ranges also being satisfactory for this purpose.

No special precautions need be observed with respect to the purity of water used for the yarn treatment so long as it is free of materials which would damage the filaments. The water need not be distilled or demineralized. Frequently it may be desirable to include therein finishing agents, antistatic agents or other materials to modify the properties of the yarn. Any of several readily available devices may be used for the application of moisture, such as spray, grooved applicator, felt, dip tank or other means best suited to the circumstances. The yarn speed in the process is limited only by the mechanical limitations of the applicator and therefore the yarn treatment is suited to coupling with other yarn treatments, as illustrated above.

According to the process of the invention, the axial tension on the yarn during winding of the package must be at least 0.02 gram per denier (0.18 g.p. Tex). tension of 0.15 g.p.d. (1.35 g.p. Tex) has been found preferable, yielding yarn exhibiting a suitable extensibility without incurring mechanical problems in the winding of the package. Higher tensions are permissible to further reduce the extensibility of the yarn so long as the elastic limit of the filaments is not exceeded.

The utility of the product is further enhanced by the application of a lubricating finish to provide a friction index which is less than about 3.0 as measured by the technique described hereinafter. A lubricant based on mineral oil is satisfactory for this purpose although other liquids which provide a lubricating film may be used.

The amount of finish usually required for 66 nylon yarn is approximately 0.7 weight percent on the yarn, although the quantity applied may range from 0.4% to 1.0%, so long as it is applied uniformly. As in the case of moisture application, excessive amounts of finish lead to undesirable deposits on the processing machinery and to messy unmanageable yarn packages. Any of the suitable devices of the prior art may he used for applying the finish. Preferably the finish is applied to the yarn before the moistening-tensio'ning step. However, the finish may be applied during the tensioning step, e.g. simultaneously with the water by using an aqueous emulsion of the lubricant.

The effect of the process of this invention on the I properties of the bulked yarns and their usefulness is illustrated in their performance in the manufacture of tufted carpets. An important aspect of pattern formation in dyed carpets is control of tuft height so that high loops and low loops can be formed according to a prescribed pattern, with sharp transition from one height to another. A yarn which is highly extensible and presents frictional drag in the tufting needles is detrimental to the tuiting operation. This difficulty appears to be magnified when the tufting is performed at a time when the relative huidity of the surrounding atmosphere is at a high level. The process of this invention permits uniform regulation of the extensibility of the very bulky yarn over a wide range of humidity conditions. The results have been judged both by laboratory testing methods and by subjective observation of carpet quality.

One measure of extensibility of the bulky yarn is determincd by the elongation of a yarn bundle when sub-' jected to a low tensile load, arbitrarily selected at 0.027 gram per denier (a. 100 gm. load for 3700-denier yarn).

' The resistance to stretching is indicated by the modulus,

the slope of the first part of the stress-strain curve for the bulked yarn. The selfcrimping tendency, or the retraction of yarn at zero tension, is observed by measuring the percent decrease in length of a length of yarn upon hanging freely for minutes after release of a tension load. The crimp force is the force exerted by a given length of yarn on the fixed clamps of a tensile testing device after 10 minutes elapsed time. The relationship of the properties measured by these methods to the quality of the carpet produced from the yarns will be shown in the examples.

EXAMPLES 1-5 Bullred nylon continuous-filament yarns were prepared at take-up speeds in excess of 500 y.p.m. The water and atmosphere were both at essentially room temperature, e.g. 25 C. The physical properties of the treated yarns are shown in Table I.

The tensile properties, tenacity and elongation, of the treated yarns were essentially identical. and unaffected by the differences in moisture and tension. The filaments were highly crimped as indicated by the crimp frequency. When boiled-off, a laboratory immersion in boiling water similar to the scouring and dyeing conditions of corn- 'mcrical processing, the crimp elongation, described in British 905,895, was substantial. The latter indicates that the treated yarns retain a high degree of bulkiness even after forming into a finished textile article. When the yarns of the various examples were formed into carpets, the yarn of Example 5 proved to be superior in terms of tuft-formation and clarity of the pattern in the carpet. Thus it appears that the performance of the bulked yarn in carpet fabrication is related to the crimping characteristics. This is exemplified by the fact that in comparison with the yarns of Examples 1 through 4, the yarn of Example 5 has a low elongation under low loading, a low self-crimping tendency (retraction and crimping force) and a relatively high modulus, all these properties being measured at high relative humidity. Example 1 demonstrates that this improvement is not accomplished by merely winding under tension.

As shown in FIGURE 4, yarns treated according to the process of the invention are less susceptible to variations, in relative humidity of the surrounding atmosphere. The elongation at low load, or extensibility, of the yarn of Example 5 changes little over the range of to 85% relative humidity, as evidenced by the lower line of FIG- URE 4. Similarly, the change in elongation of the yarn of Example 3, also treated at 550 gm. tension, is relatively small over the range of relative humiditics. The yarns of Examples 2 and 4, treated under very light tension, are affected to a greater extent by humidity.

The effect of applying liquid moisture is also apparent from FIGURE 4. The yarns of Examples 4 and 5, containing approximately 6% moisture content, have a s'gnificantly lower tendency to stretch than the yarns of Examples 2 and 3. The differences among the yarns are less evident at low humidities. It is indeed surprising to find that the sensitivity of a highly oriented hydrophobic yarn to changes in atmospheric humidity would be diminished by the application of iiquld water at room temperature while the yarn is under tension.

Table 1 NYLON YARN Example Yarn tension:

At moisture appln., g.p.d. 0 013-. 02 15 013-. 02 15 At winding, g.p.d .12 (Jl3. 02 .15 013-. 02 .15 Yarn moisture. percent by wt" 1. (H. 5 3 6 6 Yarn finish content, percent by wt 0. 1 0. 7a 0.75 0.75 0. 75 Tenacity, g.p. 3. 4 3. 4 3. 4 3. 5 Elongation at; break, percent 53 5O 49 Crimps er inch after boil-oif 18 20 20 16 Crimp e ongation alter boil-0t], percent 83 83 77 67 Stressstrain properties at 85% relative humidity:

Yarn elongation at .027 g.p.d. loading,

percent 7. 5 7. 5 5. 5 5. 3 3. 6 Initial modulus, g p.d 2. 1 1. 1 2. 2 2. 5 3. 6 Retraetion, percent 8. .3 8. 0 7.0 4. 0 4. O Crimping force, g.p.d 2. 1 2. 1 3. 7 2. 1 1. 4

by the method and apparatus illustrated in FIGURE 3. Nylon 3700-denier yarns with 204 filaments of trilobal cross-section were crimped in a plasticizing stream of heated air under identical conditions. The bulked yarns were moistened with various amounts of water while The effect of moisture applied under tension, for the yarns of Examples 2 through 5, is illustrated more clearly in FIGURE 5. The high-humidity low-load elongation (or humid-extensibility), decreases as both yarn moisture content and treatment tension increase. Based on the apunder various tensions and then wound up intoapackage pearance of tufted carpets, it appears that superior re- 'ditions in commercial use.

available magnetic, electrical or mechanical types. yarn is continuously pulled through the eye of a tufting 7 sults are achieved when the yarn extensibility is less than The data of FIGURES indicate that in the case of 66 nylon the treatment tension should exceed .02 g.p.d.

illustrated in FIGURE 6. The data were obtained from a series of yarns treated as in Examples 1-5. Yarns 8 index and the finish content of the yarns of Examples 6 to is apparent from FIGURE -8. The friction index decreased to a low and uniform level when the finish content of the yarn exceeded 0.4%. Carpets made from yarns with a friction index less than 3.0 were superior with respect to definition of tufts and pattern to those produced from yarns with lesser amounts of finish. Hence, adjustment of the yarn finish content to obtain a suitably low friction index provides a further improve- :tre'ated under higher'tension and at higher moisture con- 10 ment in the product and process of this invention.

Table II RELATIONSHIP BETWEEN FRICTIONAL CHARACTERISTICS AN D FINISH CONTENT OF YARN Example Finish content, wgt. percent 0. 1 0.2 0.51 O. 66 O. 93 Moisture Content, wgt. percent 4. 8 6. 0 6. 1 6. 3 6. 3 Denier 3, 730 3, 790 3, 770 3, 770 3, 780 Tenacity, g.p.d 3. 3. 5 3. 6 3. 4 3. 6 Elongation, percent. at brcak 47 48 48 51 49 Crimps per inch after boil-o 13 14 13 i4 14 Crimp Elongation after boil-off percent. 66 64 67 66 64 Friction Index, Tz/T 4. 05 3. 00 2. 73 2. G4 2.70

tent have a higher initial modulus and are less affected by humidity. A higher modulus is indicative of a lower yarns under tension with water are most pronounced when the yarn possesses a low and uniform friction index. If the frictional characteristics of the yarn are nonuniform, an extensible yarn is likely to be stretched to different degrees as the individual tufts are formed in carpet fabrication. It follows that proper use of a lubricant can readily contribute to the uniformity of tuft-formation. A test of yarn frictional characteristics has been devised to evaluate the effect of finish. In this test the bulked yarn is drawn through the eye of .a tufter needle at controlled speeds and room humidities simulating actual tufting con- Yarn tension is measured, dynamically, upstream and downstream from the needle. The ratio of outgoing tension, T to ingoing tension, T at. constant T is taken as the friction index.

The apparatus and method for determination of the friction index is illustrated in FIGURE.9. The bulky yam to be tested is withdrawn from package 26 regulated at a constant value, approximately .008 g.p.d., by tension regulator 61, which may be any of the readily The needle 63 so that the shank of the needle bisects a 25 included angle between the ingoing and outgoing threadline. The take-off speed of the yarn is maintained at 45 y.p.m. by suitable means such as take-off roll 65 and separator roll 66. Ingoing tension, T is measured by V tensometer 62 and outgoing tension, T is measured by tensometer 64. Data measured by this technique are reported in Table II and are discussed below.

EXAMPLES 6-10 oil lubricating finish. The relationship between friction The practice of this invention may be utilized with numerous known synthetic fiber-forming materials. These include such organic materials as polyamides, e.g., poly(caproamide) and poly(hexamethylene adipamide); polyesters, e.g., terephthala-te esters of ethylene glycol and a trans-p'hexahydroxylylene glycol; polyalkylenes, e.g., polyethylene and polypropylene; .polyvinyls and polyacrylics, e.g., polyacrylonitrile, as well as copolymers.

The yarns are not restricted to filaments of any particular'cross-section. The trilobal filaments of the above examples are preferred vfor many textile articles. ments of round, cruciform, delta-shaped, ribbon, dumbbell and other non-circular cross-sections can be processed as well. The filaments may also be of various sizes as measured by denier per filament. Further, a mixture of filament deniers and cross-sections may be used in this invention.

While the product of this invention has been shown to be particularly useful for the manufacture of tufted carpets, it retains the properties and attributes of the bulky yarns which are fed to this process and which are useful for other textile articles such as woven and knit goods.

What is claimed is:

1. Method for reducing the extensibility of a bulky yarn composed of crimped continuous filaments of a polyamide, said method comprising applying liquid water to a running length of the yarn at normal temperatures while the yarn is under a tension of at least 0.02 gram per denier and winding the water-treated yarn under tension into a package, the quantity of water applied to the yarn being at least 50% of the equilibrium content of the filaments at relative humidity as measured at 20 C.

2. Method of claim 1 wherein the said bulky yarn has a friction index less than about 3.0.

3. Method for reducing the extensibility of a bulky yarn composed of crirnped continuous filaments of poly- (hexamethylene adipamide), said method comprising applying liquid water to a running length of the yarn at normal temperatures while the yarn is under a tension of at least 0.02 gram per denier and Winding the watertreated yarn under tension into a package, the quantity of water applied to the yarn being sufiicient to provide a yarn water content of at least 4% by weight.

4. Method of claim 3 wherein the said bulky yarn has a friction index less than about 3.0.

5. Method of claim 3 wherein the said yarn water content is 4 to 10% by weight.

6. In a method for producing a bulky yarn composed of continuous filaments of a polyalnide, which method includes the steps of spinning said filaments, collecting said filaments in the form of a yarn, bulking and relaxing the filaments of the yarn, and subsequently winding the bulky yarn under tension into a package; the improvement wherein the winding of the bulky yarn into said package includes the step of applying liquid water to a r nning length of the yarn at normal temperatures while the yarn is under a tension of at least 0.02 gram per denier, the quantity of water applied to the yarn being at least 50% of the equilibrium content of the filaments at 100% relative humidity as measured at 20 C.

7. In a method for producing a bulky yarn composed of continuous filaments of poly(hexame'thylene adipamide) which method includes the steps of spinning said filaments, collecting said filaments in the form of a yarn, bulking and relaxing the filaments of the yarn, and subsequently winding the bulky yarn under tension into a package; the improvement wherein the winding of the bulky yarn into said package includes the step of applying liquid water to the yarn at normal temperatures While the yarn is under a tension of at least 0.02 gram per denier, the quantity of water applied to the yarn being sutlicient to provide at least 4% water based on the weight of the yarn. V

8. A bulky yarn produced by the method of claim 1..

References Cited by the Examiner UNITED STATES PATENTS 2,364,467 12/1944 Nickerson 2859.5 2,837,809 6/1958 Muller 28-76 2,960,752 11/1960 Sonnino 28-76 3,145,133 8/1964 Barton.

ALEXANDER H. BRODMERKEL, Primary Examiner. A. L. LEAVITI, Assistant Examiner.

Claims

1. METHOD FOR REDUCING THE EXTENSIBILITY OF A BULKY YARN COMPOSED OF CRIMPED CONTINUOUS FILAMENTS OF A POLYAMIDE, SAID METHOD COMPRISING APPLYING LIQUID WATER TO A RUNNING LENGTH OF THE YARN OF NORMAL TEMPERATURES WHILE THE YARN IS UNDER A TENSION OF AT LEAST 0.02 GRAM PER DENIER AND WINDING THE WATER-TREATED YARN UNDER TENSION INTO A PACKAGE, THE QUANTITY OF WATER APPLIED TO THE YARN BEING AT LEAST 50% OF THE EQUILIBRIUM CONTENT OF THE FILAMENTS AT 100% RELATIVE HUMIDITY AS MEASURED AT 20*C.