US3596459A

US3596459A - Process of producing a nonstretch or low-stretch composite yarn of super high bulkiness

Info

Publication number: US3596459A
Application number: US838203A
Authority: US
Inventors: Osamu Wada; Yoshiyuki Sasaki; Masaaki Tomiji
Original assignee: Teijin Ltd
Current assignee: Teijin Ltd
Priority date: 1967-03-08
Filing date: 1969-07-01
Publication date: 1971-08-03
Anticipated expiration: 1988-08-03
Also published as: GB1224554A; US3495393A; GB1224553A; FR1564060A; CH469109A

Abstract

Process of producing a nonstretch or low-stretch composite yarn of super high bulkiness. At least one core yarn is fed, and at least one covering yarn having a plurality of filaments is tensioned and relaxed and is then fed in an overfed state to a wrapping point where it is wrapped around the core yarn. The rate of delivery of the covering yarn to the wrapping point is such that the ratio of the length of the covering yarn is from 110-300 percent of the length of the core yarn per unit length of the composite yarn. The composite yarn has a final twist imparted thereto.

Description

United States Patent Inventors Osarnu Wada lbaragi-shi;

Yoshiyuki Sasaki. lbaragi-shi; Masaaki Tomiji, Kashiwara-shi. all of. Japan 838,203

July 1, 1969 Division of Ser. No. 710,138, Mar. 4, 1968. Pat. No. 3,495,393 Aug. 3, 1971 Teijin Limited Osaka, Japan Mar. 8, 1967. Mar. 8, 1967, Mar. 8, 1967, May 23, 1967, May 23, 1967, May 23, 1967 Japan 42/14641, 42/ 14643, 42/14644, 42/43351. 42/43352 and 42/43353 Appl. No. Filed Patented Assignee Priority PROCESSOF PRODUCING A NONSTRETCH OR LOW-STRETCH COMPOSITE YARN 0F SUPER HIGH BULKINESS 5 Claims, 12 Drawing Figs.

US. Cl 57/ 160, 57/12 111:. ct 1165b 81/06 [50] Field oISearch 57/12, 140

[56] References Cited UNITED STATES PATENTS 3,068,636 12/1962 Masurel.... 57/14 4 X 3,097,471 7/1963 Foster 57/169 X 3,257,793 6/1966 Abbott 57/163 3,264,816 8/1966 Jn i 57/ 169 3,410,077 11/1968 Marzocchiet al., 57/160X 3,410,078 1 1/1968 Freedman et a1. 57/160 X 3,447,302 6/1969 Field, Jr 57/160 X Primary Examiner-Stanley N. Gilreath Assislan! E.\-aminer -Werner H. Schroeder Anomey-Wenderoth. Lind & Ponack ABSTRACT: Process of producing a nonstretch or low-stretch composite yarn of super high bulkiness. At least one core yarn is fed and at least one covering yarn having a plurality of filaments is tensioned and relaxed and is "then fed in an overfed state to a wrapping point where it is wrapped around the core yarn. The rate of delivery of the covering yarn to the wrapping point is such that the ratio of the length of the covering yarn is from 1 lO-300 percent of the length of the core yarn perunit length of the composite yarn. The composite yarn has a final twist imparted thereto.

PATENTEUAUG 3m 3,596,459

sum

1 or 5 INVENTORS',

OSMVHJ WIALA,

YOSHIYUKI ISASAKI M10 MASAAKI TDMIII BY Zak ATTORNEKS PATENTED NIB 3 19?! SHEET 2 BF 5 INVENTORS.

OSAMU wAbA YOSHIYUKL sAsAm am MASAAKI "Town BYLOIMAAMIXMZIN.

ATTORNEYS PATENTEUAUB am 3,596,459

SHEEI'J 0F 5 a mum IW/IIII INVENTORS.

OSAMU WADA- YOSHIYLIKI sAsAW's MASAAKI TOW]! BYQMM. 1MLMM.

ATTORNEY!) FIG. 8

INVENTORS OSAMU WADA YOSHIIYUKI SASAK! MASAAKI TOMIJI ATTORNEYS PATENTED AUG 3:911 3,596,459

SHEET 5 OF 5 INVENTORS OSA WADA YOS UKI SASAKI MASAAKI TOMIJI ATTORNEYS refers to any mono- BACKGROUND OF THE INVENTION This invention relates to a nonyarn of super high bulkiness, and a process of producing said composite yarn. As used herein'the term-"inelastic yarn" or multi-filament yarn, crimped or uncrimped, of fiber except polyurethane and rubber, and spun yarn of the same Fiber. For example such ,fibers include polyester fiber, polyamide fiber, polyacrylonitrile fiber, polyvinyl chloride fiber, polypropylene fiber, glass fiber, steel fiber; The term crimped yarn" refers to any synthctic'fil'ament yarn crimpedby presently known processes such as twisting and setting techniques false twisting, stuffer box, or any other means of producing texturing.

The well-known c'rimped yarn has a soft feeling because of which it can be advantageously andbeneficially used in some commercial fields. But it has the drawback that it has insufficient liveliness when his fabricated into apparel, and this problem precludes wider application in commercial fields. A solution has been continuously demanded for this problem. Any suitableli'veliness of crimped yarn can be attained as desired by increasing its denier in successive steps for increasing the degree of fineness. However,.as the liveliness increases, thesbft feeling inherently possessed by the crimpe'd or low-stretch composite yarn disadvantageously decreases. Furthermore, the Crimped yarn has a defect that the crimp does not keep the fabric in a bulky statedue to excess tension throughout many steps of the manufacturing process for fabricating it into apparel.

The present invention is directed to a composite yarn in which a majority of the livelinessis imparted by the core and the soft feeling mainly by the covering yarn, so that the resulting yarn will have both liveliness and a soft feeling.

SUMMARY OF THE INVENTION lt isthe most important object of the present'invention to provide a process of producing a nonstretch-or low-stretch composite yarn having both super high bulkiness and suitable livelinessi The present invention is characterized by the fact that the cover filaments which-aretin a series'of helical turns are relaxed consecutively as they are wrapped around the core and both the core and cover are gathered and finally twisted so that the cover is wrapped around the core to form a non stretch or low-stretch composite yarn of super high bulk. The cover is overfed relative to the core during the wrapping operation so that significant bulkiness can be obtained. By overfed is meant that a length of covering yarn greater than the length of the core yarn is fed and wrapped around the core yarn.

Further objects and features of the invention will be apparent from the following description taken with the accompanying drawings, in which:

FIGS. 1A and 1B are two schematicviews taken on the opposite side ofa core yarn from each other, greatly enlarged, and showing the yarn accordingtothe invention; and

FIGS. 2 to 9 are schematic 1 views illustrating various modified apparatuses for practicing the process of the invention.

Throughout the Figures, similar'numerals refer to similar parts-of the apparatuses.

Referring now in detail to the drawing, a composite yarn is shown in FIGS. 1A and 1B which yarn includes a core 1 around which a covering yarn is wrapped. Each filament of the covering yarn is in a series of h elical turns and in a bulky condition so that an'unusual bulkiness fiber available in staple or filament form can be used as a core isachieved. Any textile,

yarn regardless of whether it is crimped or not. Such fibers include natural 'fibers such as cotton and wool, and synthetic fibers such as polyester fiber, nylon fiber, polyvinyl chloride fiber, and such mineral fiber as glass fiber and steel fiber. As for the covering yarn, any filament available in crimped form can be included and any operation by which the crimp is originally formed can be used such as texturing, use of a stuffer box, gear crimping, torque crimping, edgecrimping, or any other crimping process. The use of a core with filaments v having a denier not less than twice that of the cover filament has been found beneficial in achieving a yarn with the desired properties. lt has been found beneficial to limit the denier of the core filament to from 4 to 20.

Any synthetic yarn available in crimped form can be used as the cover filament, and it has been found desirable to limit the denier to less than 5.

The foregoing limitations on the fineness of the core and cover filament are most critical for giving to the resulting yarn the intended liveliness, due mainly to the core, and the soft feeling due mainly to the cover. When the critical factors of fineness of bothcore and cover are kept within these limits, the composite yarn resulting from the process of this invention has both high bulkiness and liveline-ss, provided that the final twist and the rate. of the cover overfeed are suitably and reasonably regulated as the case requires. For example, it has been found that when each filament of the core yarn has a denier less than 4 or more than 20, the desired liveliness can not :be achieved. lt has also been found that when the filament of length of the cover falls below the cover has a denier more than 5, the desired soft feeling cannot be achieved. The cover filaments are longer by about 10 to 200 percent, preferably from l0 to 50 percent, than that of the core per unit length of the resulting composite yarn so that the cover is caused to cover the core. If the excess of the 10 percent of the core length per unit length of the resulting yarn, the coverin glthroughout the full length of the core has been found to be insufficient. If it rises above 200 percent, the sheath formed by the covering yarn will be loose and the appearance of the yarnwill deteriorate to such a degree that it cannot be used commercially. The excess of the cover length should be kept in the rangeof from ID to 50 percent relative to the length of the core. Crimped yarns made by twisting and setting techniques can be advantageously used as a core to prevent the cover from sliding thereon, and such a core will produce added bulkiness. The use of two to three filaments with each filament having a denier from l0 to 20, has been found to be best for achieving liveliness, and the use of core having total denier of from 50 to l0() and a cover having a total denier of from 75 to is best for achieving bulkiness.

It is to be noted that the length ofthe core and cover is measured under reasonable tension within the tolerance recognized in the trade.

Referring now to FIG. 2, there is :shown an apparatus for producing a composite yarn in accordance with this invention by a twisting method. A core yarn l advances through a pair of nip rolls 3 from any package (not illustrated) and the covering yarn 2 also advances from any package (not illustrated), through a back pair of drafting rolls 4, and theiice through an intermediate pair of rolls 5 to the front pair of rolls 6. The linearspeed of the intermediate pair of rolls 5 is greater than that of theback pair of rolls 4 so that the covering yarn is tensioned when passing through the zone defined between the back pair and the'intermediate pair of rolls. The tension load is withinthe range of from 0.5 to 2.5 gram per denier and the elongation is generally within the range of from 1.5 to 12 percent;relative to the original length. The-covering yarn 2 advances at an angle to the core axis at a faster speed than that of the core yarn to facilitate wrapping the cover'therearound. The core-and cover pass together through a snail wire 7, a ring traveler Q'and then are wrapped around the bobbin l0 to form a package 11 thereon. The core and cover are finally twisted together and cover 2 is twisted there-around by rotating the bobbin through a driven pulley mounted on the spindle (not ilmove up and down in relation to the bobbin 10 to build up a package ll'thereon. A.twist of from 50 to 1,500 turns per meter is given to the composite yarn. It has been found that if the number of turns falls below 50 per meter, the cover slides on the core and above l,500 the softfeeling decreases. The

' rotational speed of the front pair of rolls 6 is less than that of ,the intermediate pair 'of rolls so that the cover passed from the intermediatepair of rolls is immediately relaxed and is inan overfed or distended state. This makes the cover yarn bulge outwardly with-each filament in a distended state so that the bulkiness achieved is significantly higher than that which could be expected from simply the inherent bulkiness. It should be noted that this phenomenon is ingeniously applied to the present invention to obtain unusually higher bulkiness.

The linear speed of the front pair of rollers 6 is significantly lessthan that of-the intermediate pair of rolls 5, so that each of the covering filaments is urged outwardly so the yarn has a significantly higher bulkiness. By slackening-immediately after the tensioning, each filame nt'of the covering yarn is caused to separate laterally from the other filaments to achieve a higher bulkiness than that which is inherent in the covering yarn. 3 It should be understood that the unusually higher bulkiness of the cover yarn is achieved by enhancement of the inherent bulkiness. While pairs of rollers have been illustrated and described as a device for producing high bulkiness, it will be understood that any tension device can be used in place of roller devices, and the distance between the'front pair of rolls 6 and the wrapping point can be changed as conditions may require. For example, the front pair. of rolls .6 can be positioned immediately adjacent the wrapping point. it has been found that the front pair of rolls can be omitted pose of simplifying the apparatus. A

In FIG. '3 is shown another type of apparatus for practicing this invention, in which the front pair of rolls 6 additionally. operates as a core feeding pair of rolls, and accurate wrapping of two yarns can be achieved. It is further found that the core can be positioned accurately near the axis of the cover at the nip of the front pair of-rolls during the wrapping process. This prevents the core yarn from being displaced from the center of the resulting.yarn toward the outside of the yarn.

' It should 'be noted that the process does not necessarily require twisting immediately after the performance of the l r'elaxing and wrapping procedures. v The apparatus shown in FIGS. 4A--4C carries out twisting separately after the core has' been wrapped with the cover. It

has been'found beneficial to carry out the process in this manner to'prevent the crimped cover yarn from being tensioned when the cover is unwound from package 110 for final twisting; since a majority of the unwinding load is borne by the core yarn 1. It has also been found that when the yarn 111 is unwound from the'package on bobbin 110, it is beneficial to brake the yarn at the letoff position for preventing the core and cover from being separated from each other during the unwinding. The apparatus inFlG. 4B differs from the apparatus of FIG..,4A in the manner inwhich the front pair of feed rollers is used for feeding not only-the cover but the core in order to achieve accurate maintenance of the core on the center axis of the cover during the wrapping process.

Now referring to FIG. 5, there is shown modified apparatus for producing the yarn of this invention. In this apparatus two core yarns are separately fed and the covering yarnenters the wrapping and twisting point so that the rate of over feed of the cover can be advantageously increased, even though a smooth monofilament yarn is used as the core yarns. For example, when the twomonofilament yarns of polyethylene terephthalate are used as said two core yarnsand crimped filaments of the same material are used as the cover, a rate of overfeed of greater than 10 percent can easily beobtained, while the 10 percent rate is found to be the absolute upper limit when the two monofilaments'are doubled and twisted and then fed to the wrapping point.

for the pur- Further for this'purpose, the covering yarn need not be wrapped only at the doubling point of the core yarns, but can be wrapped at any point on one of the core'yarns from the feed roll to the doubling point.

As shown in F IG. 8, core yarns are fed from packages land 1' by feed rolls 2 and 2'. Covering yarn is .fed from package 5 through feed rolls 6 and 6' and is wrapped on one core yarn at point A" between core feed roll 2' and twisting point A. The finished yarn is run through the snail wire 4 and ring traveler on rig 3 onto the yarn package; The .coverihg yarn is preferably wrapped around the core yarn by the'action of the torque of the core yarn transmitted from the twisting pointiA.

Referring now to FIG. 6, there is shown anothermodified apparatus for carrying out the process of this invention; In the apparatus, the bottom roller 3' of the feed rolls has the lower portion passing through an adhesive agent in a tank 3", so that Referring now to H0. 7, there is shown a further modified I apparatus for carrying out the process of this invention. In the apparatus, a pair of fluted rolls 3 are used as feed rolls so that the core is crimped and slippage of the cover can be prevented during the twisting operation. I

HO. 9 shows 'another'embodiment similar to that of FIGS. 5 and 8, in-which in addition to the two core yarn packages there are two covering yarn packages 5 and -5'. Single feed rolls 2 and 6 are provided for both core yarns and both covering yarns. The respective core yarns and covering yarns'are joined at points B and C and thetwo covered yarns doubled between points B and C and the snail wire 4.

One of the most preferred embodiments of this invention is a process for preparing a low-stretch high-bulk yarn, characterized in that there is used as the cover a crimped bulky multifilament yarn in which the individual filaments are distended and which is obtained by twisting in the S direction (or Z direction.) heat-setting and untwisting, and as the core there is used a crimped multifilament yarn, and the monofilaments of which have a denier twice or more as large as the cover yarn and obtained by twisting in the opposite direction from the cover yarn, namely, 2 (or S) direction," heat-setting and untwisting. The length of the coveryarn is 10-200 percent larger than the core yarn and the thus produced yarn has imparted thereto a twist of 50-l,500 turns per meter in the same direction as that in which the core yarn is twisted, namely the Z (or S) direction. A composite yarn obtained according to this process is bulky and has good liveliness because a 'crimped yarn having thick monofilaments is used as a core. lt

-' also possesses a soft. feel because of the use of a torque characterized in that as the'co ver'there is used acrimped.

crimped yarn having thin monofilaments as a covering yarn. When the core'iswrapped with the covering yarn and't'wisted, the covering yarn is. twisted in the direction opposite to that employedwhen originally preparing the covering yarn and consequently the resulting yarn is more bulky.The core yarn is given a substantially larger torque than fthe' covering yarn when it is twisted together with the covering yarn, and is twisted in the direction of twisting the core yarn,.namely in the direction of less overall yarn torque. Thus, a yarn having an overall low torque is obtained;

1 Another of the most preferred embodiments of this invention is a process for preparing a low-stretch high-bulk yarn,

bulky multifilament yarn in which the individual filaments are dispersed and which is obtained by twisting, in the-S direction- '(or 2 direction), heat-setting and untwisti ng, and as the core there is used a crimped multifilament yarn havinga monofila- -ment denier twice or more as large as that of the cover yarn and haying a number of monofilaments less than one-half the number of the first-mentioned yarn. The core yarn is twisted in the opposite direction. namely. the Z (orS) direction, heatset and untwisted. The length of the cover yarn is lO--200 percent greater than the core yarn. The cover yarn is posigiven in the 2 direction. Thus, a low-stretch high-bulk yarn was obtained which had a very low torque, balance being maintained by the sum ofZ torque of the core yarn, S torque of the covering yarn and S torque generated at the time of tioned surrounding the core yarn with the core yarn at the 5 twisting. center, and they have imparted to them twist of from 5()-- Example 3 L500 turns per meter in the opposite direction to the twisting A 40-denier/two-filament polyester yarn was used as the of the core yam. namely the S (or 2) direction. When the core core yarns. Using the apparatus in FIG. 5, a 75-denier/36-filayarn iswrapped with covering yarn and twisted according to ment false-twisted polyamide covering yarn having'a trianguthis process, the twist is imparted in the direction opposite to lar cross section was overfed by 30 percent relative to the core the twist of the core yarn for the purpose of untwisting the yarn, and a twist of 200 turns per meter was given. Thus, a core. yarn. Then the core yarn becomes very bulky. and it is nonstretch high-bulk yarn was obtained. Prior to covering, the possible to obtain a bulky composite yarn. covering yarn had been elongated by 10 percent, and relaxed Exam I 1 so that it was under no tension. The covering yarn was fed into i a point where the two core yarns intersected each other. They A 45-denier/three-filament false twisted polyester yarn (Z were twisted together while part of the covering yarn was torq e) w used as core yarn-and covered with a nibeing held between the two core yarns, and were associated er/48-filament false-twisted polyester yam (Z torqu With tightly into a covered yarn. The obtainedyarn had good bulkilhe pp r 0f lG.i3, prior towrapping the core yarn, th ness, and had a soft feeling and unique luster. lt was suitable as covering yarn had been widened to a widthof about7 mm. in a material for woven fabrics. a direction at right angles to the yarn axis by elongating it by 5 Example 4 percent and. relaxing it so that it was under no tension. The Using the apparatus in FIG. 4, a low-stretch high-bulk yarn covering yarn was overfed by 30 percent relative to the core was prepared in the same manner as in example 1 using a 75- yarn, and the core yarn was fed into the center portion of the denier/IS-filament false-twisted yarn as a core and a IOO-denicovering yarn. A low-stretch super highbulk yarn was ob er/36-filament side-by-side type conjugate filament yarn comtained by imparting tothe composite yarn a final twist of 600 posed ofa polyethylene terephthalate resin and'a polyethylene turns per meter in the Z direction. Two such low-stretch super naphthalate resin as a cover. high bulky yarns were doubled, and given a final twist of 480 Example 5 turns per meter in the S direction to make a material for A spun yarn of 64 S (metric count) from out staples of woven fabric. polyethylene terephthalate (4d, 76 :mm.) was used as a core, A woven fabric of a matt weave was prepared from the said and a false-twisted l50-denier/48-filament polyethylene yarn, and subjected to an ordinary finishing process such as terephthalate was used asa covering yarn. Using the apparatus scouring, relaxing, heat-setting, dyeing and again heat-setting. in H0. 6, powder of polyethylene terephthalate with which It had the properties as shown in the following table. For the 35 mole percent of isophthalic acid had been copolymerized was sake of comparison, awoven fabric was prepared from ordinaadded to the surface of the core yarn, and the thus treated ry false-twisted yarns using the same technique both in weavcore yarn was wrapped with a covering yarn which had been ing and in finishing. The said ordinary false-twisted yarn was overfed by 70 percent relative to the core. A nonstretch highprepared by imparting a twist of 200 turns per meter in the Z bulk yarn was obtained by covering in the same manner as in direction to a l-denier/48-filament (Z torque) polyester 40 example I. The twist imparted at this time was 300 turns per yarn, and imparting a final twist of I turns per meter in the 5 meter. The obtained yarn was dry heat-treated at 200 C., and direction to two of such polyester yarns which had been dollcoalesced points were developed partly on the core and coverbleding yarns.

RESULT OF TESTING OF WOVEN FABRICS Woven fabric Woven fabric prepared from prepared from the yarns of the the ordinary present invenfalse-twisted Direction 7 Unit tion yarns Density ii 3r?.1 Etiiiifiii; 1;: 3% Thickness... \Irn. 0.51 0.46 Bnlkiness Cm. /g 2.6 Bending stiffness. Warp, G.-cm. ,'cm 29.0X10 21.8X 0- Bending recovery... Welt Percent 90.0 83.2

The bending stiffness and bending recovery were measured in accordance with. the description in the Journal of the Textile institute, 1964, vol. 55, T 516.

As can be seen from the above results, the fabric woven from the yarns of the present invention has very good bulkiness, and an excellent liveliness. It is impossible to give a definite measured value to the liveliness since the liveliness can only be sensed by humans. it is generally said, however, that the liveliness is excellent when the bending stiffness is appropriate and the bending recovery is good. Incidentally, the fabric woven from the yarn according to the present invention was far softer and had an excellent hand as compared with the woven fabric prepared from the ordinary false-twisted yarns.

Example 2 A Z torque 75-denier/eight-filament false-twisted polyester yarn was used as a core. Using the apparatus in FIG. 2, and S torque l00-denier/48-filament false-twisted polyester yarn was overfed by 20 percent relative to the core yarn in-the same While several embodiments of this invention have been illustrated and described herein, it will be apparent that modification thereof may be made without departing from the scope ofthe invention as defined in the appended claims.

What we claim is:

1. A process of producing a nonstretch or low-stretch composite yarn of super high bulkiness, comprising the steps of a feeding at least one core yarn, tensioning a crimped covering yarn having a plurality of filaments at a tension load of from 0.5 to 2.5 grams per denier to remove the crimps therefrom, and then relaxing said covering yarn, feeding the relaxed covering yarn with an overfeed to a wrapping point, wrapping said relaxed covering yarn around the core as a cover to form a composite yarn, and imparting twist to the composite yarn, the rate of delivery of the covering yarn to the wrapping point being such that the ratio of the length of the covering yarn is from 1 10 to 300 percent of the length of the core yarn per unit manner as example I, and a twist of 300 turns per meter was length of the composite yarn.

2 The process as claimed in claim I wherein the tensioned and relaxed covering yarn is fed into a pair of feed rollers and the separately fed coreyarn is joined to the covering yarn at the feed rollers and is thereby covered with the covering yarn. 3. A process of producing a nonstretch or low-stretch composite yarn of super high bulkiness, comprising the steps of forming at least two separate yarns into a core yarn by separately and angularly feeding the separate yarns to a point and twisting them at said point; feeding said one core yarn; tensioning a erimped covering yarn having a plurality of filaments to remove the crimps therefrom and then relaxing said covering yarn; feeding the relaxed covering yarn in an overfed state to said twisting point and wrapping said relaxed coveringyarn around the core as a cover to form a composite yarn, the rate of delivery of the covering yarn to the twisting point being such that the ratio of the length of the covering yarnis from yarn, feeding the relaxed covering yarn in an overfed state to a wrapping point and wrapping said relaxed covering yarn around the core as a cover to form a composite yarn. the rate of delivery of the covering yarn to the wrapping point being such that the ratio of the length of the covering yarn is from 110-300 percent of the length of the core yarn per unit length of the composite yarn, and finally imparting alwist to the composite yarn.

5. A process of producing a nonstretch or low-stretch composite yarn of super high bulkiness. comprising the steps of forming at least two separate yarns into, a core yarn by separately and angularly feeding the separate yarnsto a point and twisting them at said point; feeding said core yarn; tensioning a erimped covering yarn having a plurality of filaments to remove the crimp therefrom and then relaxing said covering ya'rn; feeding the relaxed covering yarn in an overfed state to a point which lies ahead of said twisting point with respect to the feed direction and wrapping the relaxed covering yarn around the core as a cover to form a composite yarn. the rate of delivery of the covering yarn to the wrapping point being such that the ratio of the length of the covering yarn is from -300 percent of the length of the core yarn per unit length of the composite yarn; and finally imparting a twist to g the composite yarn.

Claims

2. The process as claimed in claim 1 wherein the tensioned and relaxed covering yarn is fed into a pair of feed rollers and the separately fed core yarn is joined to the covering yarn at the feed rollers and is thereby covered with the covering yarn.
3. A process of producing a nonstretch or low-stretch composite yarn of super high bulkiness, comprising the steps of forming at least two separate yarns into a core yarn by separately and angularly feeding the separate yarns to a point and twisting them at said point; feeding said one core yarn; tensioning a crimped covering yarn having a plurality of filaments to remove the crimps therefrom and then relaxing said covering yarn; feeding the relaxed covering yarn in an overfed state to said twisting point and wrapping said relaxed covering yarn around the core as a cover to form a composite yarn, the rate of delivery of the covering yarn to the twisting point being such that the ratio of the length of the covering yarn is from 110-300 percent of the length of the core yarn per unit length of the composite yarn; and finally imparting a twist to the composite yarn.
4. A process of producing a nonstretch or low-stretch composite yarn of super high bulkiness, comprising the steps of feeding at least one core yarn by passing it through a pair of fluted nip rolls for crimping the core yarn, tensioning a crimped covering yarn having a plurality of filaments to remove the crimp therefrom and then relaxing said covering yarn, feeding the relaxed covering yarn in an overfed state to a wrapping point and wrapping said relaxed covering yarn around the core as a cover to form a composite yarn, the rate of delivery of the covering yarn to the wrapping point being such that the ratio of the length of the covering yarn is from 110-300 percent of the length of the core yarn per unit length of the composite yarn, and finally imparting a twist to the composite yarn.
5. A process of producing a nonstretch or low-stretch composite yarn of super high bulkiness, comprising the steps of forming at least two separate yarns into a core yarn by separately and angularly feeding the separate yarns to a point and twisting them at said poinT; feeding said core yarn; tensioning a crimped covering yarn having a plurality of filaments to remove the crimp therefrom and then relaxing said covering yarn; feeding the relaxed covering yarn in an overfed state to a point which lies ahead of said twisting point with respect to the feed direction and wrapping the relaxed covering yarn around the core as a cover to form a composite yarn, the rate of delivery of the covering yarn to the wrapping point being such that the ratio of the length of the covering yarn is from 100-300 percent of the length of the core yarn per unit length of the composite yarn; and finally imparting a twist to the composite yarn.