US3316705A

US3316705A - Production of artificial yarns

Info

Publication number: US3316705A
Application number: US554209A
Authority: US
Inventors: Nava Mario
Original assignee: Ernest Scragg and Sons Ltd
Current assignee: Ernest Scragg and Sons Ltd
Priority date: 1958-05-13
Filing date: 1966-05-31
Publication date: 1967-05-02
Anticipated expiration: 1984-05-02
Also published as: DE1410376B1; MY7000069A; CH413682A; CY528A; US3462933A; CH411217A; GB921583A

Description

May 2, 1967 M. NAVA 3,316,705

PRODUCTION OF ARTIFICIAL YARNS Original Filed Oct. 2, 1963 INVENTOR. flz aria /1/a/ a United States Patent 3,316,705 PRODUCTION OF ARTIFICIAL YARNS Mario Nava, Macclesfield, England, assignor to Ernest Scragg & Sons Limited, and Cheslene & Crepes Limited, both of Macclesfield, England Continuation of application Ser. No. 313,392, Oct. 2,

1963. This application May 31, 1966, Ser. No. 554,209 Claims priority, application Great Britain, May 13, 1958, 15,240/ 58 26 Claims. (Cl. 57-157) This application is a continuation of application Ser. No. 313,392, filed Oct. 2, 1963, now abandoned, which is itself a continuation-in-part of copending application Ser. No. 12,536, filed Mar. 8, 1960, and entitled Production of Synthetic Yarns, now abandoned, which is itself a continuation-in-part of application Ser. No. 782,536, filed Dec. 23, 1958, and entitled, Methods of Treating Yarns and to Yarns Obtained Thereby, now abandoned, and application Ser. No. 812,744, filed May 12, 1959, and entitled, Production of Synthetic Yarns, now abandoned.

The present invention relates to a process for manufacturing bulked thermoplastic ya-rn.

It is known to manufacture bulked yarn by twisting the yarn and setting the twist therein, as, for example, by heating the yarn and then untwisting the same. In this manner the individual yarns which originally are substantially straight become crimped and thus the yarn is bulked. These yarns are highly contractile, for example, to the extent of ZOO-350%. In other words, when the yarn is held straight but not stretched to such an extent that it will break, and then released, the yarn will contract in length from 200-35 0%. Yarn of this type is extremely useful in the making of articles such as stretch socks, but the yarn has uneven shrinkage properties and does not have dimensional stability when knitted or woven so that it becomes necessary to further treat the yarn, and thus undesirable inconvenience and cost results. In other words, in order to render such yarn suitable for warp knitting and also for weaving, the yarn must go through the long and rather expensive processes of stapling, drafting and spinning.

One of the Objects of the present invention is to avoid the above drawbacks by providing with the process and apparatus of the invention a yarn which while almost as highly bulked as a fully twist crimped yarn, nevertheless is contractile to an extent substantially less than 50%, and in actual practice the yarn is found to be contractile to an extent of only -20%.

Another'object of the present invention is to provide a process and apparatus according to which this yarn can be produced in a rapid inexpensive manner from any thermoplastic yarn, even such thermoplastic yarns as in the past have been ditficult to work with.

It is a further object of the invention to provide an extremely suitable arrangement for handling a soft yarn package in order to subject the same to the influence of a setting fluid.

A still further object of the invention is to provide an apparatus which can be very easily regulated so as to be adapted to the treatment of any thermoplastic yarn.

It is still another object of the invention to provide a process according to which the yarn is partially set during the false twist crimping thereof by applying to the yarn a temperature which is relatively low and which need not be precisely maintained at a given value.

The object of the invention also includes an apparatus which includes an extremely simple and eflicient structure for applying heat to the yarn.

With the above objects in view the invention includes in a process for producing a yarn which is almost as highly bulked as a fully twist crimped yarn and which is contractile to the extent of less than 50%, the steps of false twist crimping a thermoplastic yarn while partially setting the same by applying a relatively low temperature thereto and while allowing the yarn to contract by approximately 3% during the twisting thereof. The yarn which is treated in this manner is delivered at a predetermined delivery speed to a take-up package, and the yarn is collected on the package while still under tension but at a speed substantially less than the delivery speed so that a soft package is provided. This soft package is then introduced into an evacuated atmosphere, and thereafter the soft package is subjected to the influence of a setting fluid. Thus, in accordance with the invention, this soft package is steamed for a period of approximately one-half hour at a pressure of 23 atmospheres.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, to-

accompanying drawings, in which:

FIG. 1 diagrammatically illustrates an apparatus in accordance with the invention shown in FIG. 1 treating a yarn according to the process of the invention; and

FIG. 2 illustrates diagrammatically the manner in which the soft yarn package of the invention is enveloped in a cheese cloth covering prior to introduction into an autocalve.

Referring to the drawing, and to FIG. 1 in particular, it will be seen that the yarn which is treated with the ethylene glycol, and the yarn is of continuous multifilament type.

The thermoplastic yarn is drawn upwardly from the supply package 10, which is supported in a conventional as pointed out above, by a feed roll means which includes a lower driven roll 12 and an upper rubbercovered roll 13 which simply rests with its own weight illustrated in FIG. 1. The roll 13 is supported for turning movement by a shaft 14 extending between and fixedly carried by a pair of arms 15 which are parallel to each other and one of which is shown in the drawing. These arms 15 are pivotally supported by a bracket 16 carried by the stationary framework 17 diagrammatically illustrated in the drawing. The arms 15 extend beyond the shaft 14 and are interconnected at their ends distant from the brackets 16 by a spacer bar 18 fixed to the arms 15 and formed with a plurality of notches so that the yarn 11 may be wound a desired number of times around the roll 13 with each loop of the yarn passing around the space bar 18 and the several loops respectively located in the notches of this bar so that the several loops cannot become fouled, and the yarn which passes into the nip between the

rolls

12 and 13 and then is wound a desired number of times around the roll 13 in the manner described above passes upwardly to the false twist means 20 which is in the form of any conventional false twist spindle driven in a purely conventional manner.

The yarn is received above the false twist means 20 by a forwarding roll means 21 whose construction is identical with the feed roll means described below, and in the same way the yarn is wound, after passing to the nip between the rolls of the forwarding roll means 21, a desired number of times around the upper rubber-covered roll 50 as to provide a desired number of loops which are prevented from fouling by a spacer bar in the manner described above. The forwarding rolls forward the yarn onto a take-up package in a manner described below.

The tension in the yarn during the false twist crimping thereof is regulated by providing a speed of the yarn at the forwarding roll means 21 which has a predetermined ratio with respect to the speed given to the yarn by the feed roll means. It is preferred to control this tension in such a way that the yarn is allowed to contract by approximately 3% during the twisting thereof, the permitted contraction being determined by the kind of yarn employed.

The twist is partially set in the yarn by applying a relatively low temperature thereto, and this is brought about by a heating means 22 which includes a curved heating surface 23. This curved heating surface 23 has been found to be of considerable advantage since it very uniformly heats the yarn as it moves rapidly past the curved heating surface 23. The surface 23 is heated by a heating coil 24, and it has been found in practice that the relatively low temperature applied to the yarn by the heating means 22 need not be maintained precisely. In other words, it has been found that the temperature may vary considerably without producing any detrimental results in the final product. However, it is essential to provide a relatively low temperature on the order of approximately 50 less than the melting temperature of the yarn. For example, the temperature applied to the yarn by the heating means 22 may be 60 less than the melting temperature of the yarn.

The temperature can be controlled by connecting the heating coil 24 to the secondary winding of a step transformer 25 having a series of taps any one of which may be selectively used for regulating the temperature of the heating means 22. The secondary winding 25 cooperates with a primary winding 26 supplied with current from the mains.

The yarn which is delivered by the delivery or forwarding roll means 21 is received by a package-forming means 30 including a lower driven roll 31. The package 32 rests on the driven roll 31 and the yarn is collected onto the package 32 whose diameter increases during collecting of the yarn. The yarn is distributed along the take-up package 32 by a conventional traverse mechanism 33. The yarn of the take-up package 32 is wound onto a tubular core capable of moving vertically, this core being guided by the vertical guides 35 of the framework diagrammatically illustrated in FIG. 1.

In accordance With the present invention the speed of the yarn at the take-up package 32 is substantially less than the speed of the yarn at the delivery or forwarding roll means 21 but is not so much less that there is no tension in the yarn reaching the take-up package. The speed of the yarn at the take-up package, controlled by the speed of rotation of the roll 31, is on the order of 30% less than the speed of the yarn at the forwarding or delivery roll means 21 so that the package 32 is quite soft. It is preferred to control the yarn by the degree of overfeed rather than by any tensioning device. In other words, while the yarn is under tension when reaching the take-up package, the tension is not of a very high order which would make it feasible to control the speed of movement of the yarn to the take-up package by a suitable tensioning device. By providing an overfeed of the yarn traveling to the take-up package it is possible to very precisely control the degree to which the yarn is tensioned as it reaches the take-up package without relying on any particular tensioning devices which could only provide a greater tension than is actually desired. Thus, reference is made to the degree of overfeed, namely an overfeed which will provide at the take-up package a speed of travel of the yarn which is on the order of 10-30% less than the speed of the yarn at the forwarding or delivery r-oll means 21, because in the actual performance of the operations the controls are carried out precisely in this way rather than by maintaining a particular tension in the yarn.

This soft package is removed from the framework 35 and is introduced into an autoclave 36. After evacuation, the autoclave is filled with steam so that the soft yarn package is influenced by this setting fluid, and the steam is applied at a pressure of 23 atmospheres for a period of half an hour. Thereafter, the yarn remains in an atmosphere of at least 50% humidity at room temperature for a period of twenty-four hours.

In accordance with the invention, before the yarn is placed in the autoclave a length of cheesecloth 37 (FIG. 2) which may be made of approximately rectangular configuration is inserted through the hollow center of the soft yarn package, and then the ends of the cheese cloth are drawn around the package into an overlapping relation, as indicated diagrammatically in FIG. 2, whereupon a string 38 is tied around the thus-enveloped package, and in this way the soft packages are extremely easy to handle and at the same time the cheese cloth does not in any way detract from the accessibility of the yarn to the setting fluid in the autoclave.

The yarn which is produced by the above-described process and apparatus of the invention is almost as highly bulked as a fully twist crimped yarn and at the same time it is contractile to an extent of less than 50%, actually on the order of 10-20%. As was indicated above, the yarn which is wound onto the take-up package is still under a substantial tension. The filaments of the yarn when wound onto the take-up package have a partially spiral or undulatory formation, and these filaments remain separate from one another without tending to twist on themselves or pigtail, so that the yarn is set in this latter condition and thus the final yarn has such filaments when the tension on the yarn is relaxed and the yarn is in a stabilized or yarn-set condition, and in addition the yarn is substantially free from torque. The significance of this yarn is immediately evident when one realizes that the yarn has considerable dimensional stability without sacrificing the highly bulked characteristics. Thus the yarn of the invention can immediately be used for knitting or weaving and all of the undesirable further processing required by conventional bulked yarn to give it dimensional stability is completely avoided. Furthermore, the yarn of the invention is substantially nontorque, so that it need not be doubled with an oppositely twisted yarn in order to provide counterbalancing of the torques, and thus the yarn of the invention can be a simple single yarn, so that this feature also represents a great advantage.

The partial setting provided by the heating means 22 is rendered partial by the fact that the crimp induced by the false twister is not permanently set in the yarn with the heating means 22. In other words, if the yarn when influenced only by the heating means 22 is straightened and permitted to contract a few times, it will be found that the yarn will simply lose its crimp after a relatively small number of extensions, whereas if the crimp were permanently set then any number of extensions of the yarn could be carried out without eliminating the crimp- In applying the invention to Terylene, of denier, a soft lively yarn was produced when feeding the yarn at a speed of 12-18 meters per minute through the false twister so as to produce a crimp of 55-80 turns per inch. The heating means 22 applied a temperature of -140 C. to the yarn, and in the autoclave the yarn was subnd heating with steam jected for -45 minutes to steam at -30 pounds per square inch pressure.

In the case of nylon yarn, the temperature of the heating means 22 applied to the yarn was as low as 70 C. but never more than 120 C. When using a high speed machine, the feed speed for Terylene may be as high as 80 mete-rs per minute, and in this case the temperature applied by the heating means 22 may be as high as 215 C. The temperature applied to the yarn by the heating means 22 is such that for the particular yarn speed which is used the thermoplastic filaments become sufiiciently hot so as to be rendered plastic, which is to say readily deformable by relatively small forces. This is because according to the process of the invention, the crimp need only be temporarily or partially set by the heating means 22. The actual setting with the process of the invention taking place in the autoclave 36.

Some particular examples of processes according to the invention are described below. In all of these examples the first temperature given is always a dry heat, applied to the yarn by drawing it over a curved heated plate. The second or steam temperature is applied to the yarn in the form of a take-up package which is removed from the machine and placed in an autoclave. In each case the steam cycle is as follows:

(a) Exhaust autoclave to at least 24'' 24 minutes.

(b) Admit steam to the required pressure for the time stated.

(c) Exhaust to at least 24" for 2-4 minutes.

Some examples of processes according to the invention are:

mercury for Example I A 150 denier nylon yarn made up of 50 filaments was twisted at the rate of 80,000 turns per minute, inserting in the yarn 60 turns per inch in the S direction. The overfeed into the heated zone was 1% and the overfeed to the take-up package was 20%. The first heating temperature (crimping) was 400 F. while the second heating temperature during treatment of the package in the autoclave by steam (relaxing) was 310 F., and this latter treatment was of 30 minutes duration.

Example 11 A 150 denier Terylene yarn made up of 72 filaments was twisted at the rate of 80,000 turns per minute, inserting in the yarn 50 turns per inch in the Z direction. There was no overfeed into the heated zone and the overfeed to the take-up package also was 20%. The first heating temperature (crimping) was 320 F. and the sec- (relaxing) was at a temperature of 275 F. and lasted for 30 minutes.

' Example III A 250 denier Terylene yarn made up of 48 filaments was twisted at the rate of 80,000 turns per minute, inserting in the yarn 37.5 turns per inch in the Z direction.

There was no overfeed into the heated zone and the overfeed to the take-up package was 22%. The first 'heating temperature (crimping) was 380 F. and the second heating with steam (relaxing) was at a temperature F. and lasted for 30 minutes.

Example IV A 75 denier Terylene yarn made up of 48 filaments was twisted at the rate of 80,000 turns per minute, inserting in the yarn 75 turns per inch in the Z direction. The overfeed into the heated zone was zero while the overfeed to the take-up package was 22%. The first heating temperature (crimping) was 340 F. while the second heating with steam (relaxing) was at a temperature of 275 F. and lasted for 30 minutes.

Example V A 200 denier cellulose diacetate yarn having 70 filaments was twisted at a rate of 40,000 turns per minute,

thespirit of the present invention.

with 50 turns per inch inserted in the yarn in the Z direction. Instead of overfeed into the heated zone, there was a 3% underfeed, and the overfeed to the take-up package was 20%. The first heating temperature (crimping) was 300 F. while the second heating with steam (relaxing) was at a temperature of 180 F. and lasted for 20 minutes.

It is to be noted that although the second heating is in every case at a lower temperature than that of the first, the severity of the sec-ond heating greater than the first, because of the presence of steam (water vapor). It has been found that the addition of water vapor to a heating cycle produces the effect of the application of a dry temperature approximately C. higher. Thus, in all of the above examples, if 70 C. is added to the steam temperature, it will be found that the resulting equivalent dry temperature of the second heating is in each case at least equal to the temperature of the first d-ry heating. It is also to be noted, as has already been indicated above, that the first temperature in all of the above examples is always considerably lower than that which would be necessary in order to set crimp permaently in the yarn. Thus, for example, where the setting temperature would be of the order of 480 F. for full crimp set, a partial set for relaxed yarn would only require about 350 F. for a first temperature. Moreover, except for cellulose diacetate in Example V above, the steaming temperature is not critical and it is generally on the order of 275 F. The speed difference between the yarn forwarding rollers located above the false twist device and the yarn Winding roller is expressed as a percentage of overfeed, i.e. the yarn take-up roller at peripheral speed is 20% less than the peripheral speed of the forwarding rollers for a 20% overfeed. The forwarding speed of the yarn is determined in accordance with its denier since, asis apparent from the above examples, the rate of insertion of twist is kept as high as possible for all yarns so as to get maximum throughput. The yarn forwarding speed can therefore be obtained by dividing the rpm. by the turns per inch inserted in the yarn.

The soft yarn package of the invention is in a condition particularly suitable for pressure dyeing, so that this feature is of particular advantage.

By way of comparison, a yarn produced according to the invention was compared with a known false twist crimped bulked yarn, and after knitting both of these yarns into a fabric these fabric were compared. In both cases the bulked yarn was two fold denier. The fabric made from the yarn according to the present invention weighed 6.9 ounces per square yard while that made conventionally weighed 8.6 ounces per square yard, but at the same time the covering power and bulky feel of the yarn of the invention was identical with that of the conventional yarn.

'It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of thermoplastic bulked yarn differing from the types described above.

While the invention has been illustrated and described as embodied in process and apparatus for producing bulked yarn, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is intended as new and desired to be secured by Letters Patent is:

1. In a process for producing a yarn which is only contractile to the extent of substantially less than 50% and which is almost as highly bulked as fully twist crimped yarn, the steps of false twisting a thermoplastic yarn while only partially setting the yarn by maintaining during said false twisting a relatively low temperature below the melting point of said thermoplastic yarn so as to obtain a partially set false twist crimped yarn which has a high contractability exceeding 50%; delivering said partially set false twisted yarn having high contractability after said false twist crimping at a predetermined speed; collecting said partially set false twist crimped yarn having high contractability delivered at said predetermined speed on a take-up package at a speed which is less than said delivery speed so that the tension of said partially set twist crimped yarn having high cont-ractability is reduced, but which speed is still great enough to retain substantial tension in said thus only partially tensioned partially set false twist crimped yarn having high contractability when the same reaches said take-up package, so that said partially tensioned partially set false twist crimped yarn of high contractability is wound up on said take-up package still under substantial tension; and finally subjecting said partially tensioned partially set false twist crimped yarn having high contractability while it is wound up under said substantial tension on said take-up package for a given period of time to a setting fluid which completes the setting of said partially tensioned partially set false twist crimped yarn, thus obtaining a relaxed false twist crimped yarn which has only a low contractability of substantially less than 50%, has substantial dimensional stability and is substantially of the non-torque type while being almost as highly bulked as fully twist crimped yarn.

2. A process for producing a yarn, as defined in claim 1, wherein during said false twist crimping of said yarn the same is allowed to contract by approximately 3%.

3. A process for producing a yarn, as defined in claim 1, wherein said false twist crimping while only partially setting, delivering, collecting and setting of said yarn are carried out in such a manner as to obtain a relaxed false twist crimped yarn which has a contractability of only 10-20%.

4. A process for producing a yarn, as defined in claim 1, wherein said yarn is collected on said take-up package at a speed which is substantially less than said predetermined speed of delivery thereof, so as to provide a soft package.

5. A process for producing a yarn, as defined in claim 4, wherein said soft package is introduced into a chamher which is subsequently evacuated and in which then said soft package is subjected to said setting fiuid for completion of setting of said yarn.

6. A process for producing a yarn, as defined in claim 1, wherein said setting is completed by steaming the soft package for a period of approximately one-half hour.

7. A process for producing a yarn, as defind in claim 6, wherein said steaming is carried out at a pressure f 2-3 atmospheres.

8. A process for producing a yarn, as defined in claim 1,- wherein said yarn is subjected to said false twisting while being drawn in upward direction.

9. A process for producing a yarn, as defined in claim 1, wherein said thermoplastic yarn is of about 60 denier.

10. A process for producing a yarn, as defined in claim 1, wherein said thermoplastic yarn is a nylon yarn.

11. A process for producing a yarn, as defined in claim 1, wherein said thermoplastic yarn is formed of a synthetic linear polymeric condensation product of terephthalic acid and ethylene glycol.

12. A process for producing a yarn, as defined in claim 11, wherein said thermoplastic yarn is maintained during falge wist crimping thereof at a temperature of 100- 14 '13; A process for producing a yarn, as defined in claim 1.2, wherein said yarn is subjected to said false twist crimping at a speed of between about 12-18 meters per minute.

14. A process for producing a yarn, as defined in claim 12, wherein said thermoplastic yarn is maintained during false twist crimping thereof at a temperature up to 215 C., and said yarn is subjected to said false twist crimping at a speed of up to meters per minute.

15. A process for producing a yarn, as defined in claim 14, wherein said partially tensioned, partially set false twist crimped yarn while wound up on said take-up package is subjected for 15-45 minutes to steam of 20-30 pounds per square inch pressure.

16. A process for producing a yarn, as defined in claim 1, wherein said thermoplastic yarn is of continuous multifilament type.

17. A process for producing a yarn, asdefined in claim 1, wherein said thermoplastic yarn is in the form of a monofilament.

18. A process for producing a yarn, as defined in claim 1, wherein the ratio between the speed of introduction of said yarn to the false twist crimping thereof and the speed of withdrawal of the false twist crimped yarn is controlled in such a manner as to allow contraction of said yarn by about three percent.

19. A process for producing a yarn, as defined in claim 1, wherein said relatively low temperature maintained during false twist crimping of said yarn is about 50 less than the melting temperature of said yarn.

20. A process for producing a yarn, as defined in claim 1, wherein said relatively low temperature maintained during false twist crimping of said yarn is between about 50 and 60 less than the melting temperature of said yarn.

21. A process for producing a yarn, as defined in claim 1, wherein said relatively low temperature maintained during false twist crimping of said yarn is about 60 less than the melting temperature of said yarn.

22. A process for producing a yarn, as defined in claim 1, wherein said speed at which said partially set false twist crimped yarn is collected on said take-up package is on the order of 10-30% less than said predetermined speed, so as to cause an overfeed and thereby to provide a soft package.

23. A process for producing a yarn, as defined in claim 1, wherein the thus obtained relaxed false twist crimped yarn is maintained on said take-up package at room temperature in an atmosphere of at least 50% humidity.

24. A process for producing a yarn, as defined in claim 23, wherein said yarn is maintained at room temperature in an atmosphere of at least 50% humidity for a period of at least about 24 hours.

25. A process for producing a yarn, as defined in claim 1, wherein said partially set false twist crimped yarn is wound up on said take-up package with the filaments of said yarn in partially spiral or undulatory formation so as to retain the filaments of said yarn separate from another and without tending to twist on themselves.

26. A process for producing a yarn, as defined in claim 1, wherein said relatively low temperature maintained during said false twist crimping is sufficiently high to render said yarn plastic.

References Cited by the Examiner UNITED STATES PATENTS 2,421,334 5/1947 Kline et al 57-157 XR 2,869,318 1/1959 Stucki 57-l57 FOREIGN PATENTS 755,580 8/1956 Great Britain.

STANLEY N. GILREATH, Primary Examiner.

MERVIN STEIN, Examiner.

Claims

1. IN A PROCESS FOR PRODUCING A YARN WHICH IS ONLY CONTRACTILE TO THE EXTENT OF SUBSTANTIALLY LESS THAN 50% AND WHICH IS ALMOST AS HIGHLY BULKED AS FULLY TWIST CRIMPED YARN, THE STEPS OF FALSE TWISTING A THERMOPLASTIC YARN WHILE ONLY PARTIALLY SETTING THE YARN BY MAINTAINING DURING SAID FALSE TWISTING A RELATIVELY LOW TEMPERATURE BELOW THE MELTING POINT OF SAID THERMOPLASTIC YARN SO AS TO OBTAIN A PARTIALLY SET FALSE TWIST CRIMPED YARN WHICH HAS A HIGH CONTRACTABILITY EXCEEDING 50%; DELIVERING SAID PARTIALLY SET FALSE TWISTED YARN HAVING HIGH CONTRACTABILITY AFTER SAID FALSE TWIST CRIMPING AT A PREDETERMINED SPEED; COLLECTING SAID PARTIALLY SET FALSE TWIST CRIMPED YARN HAVING HIGH CONTRACTABILITY DELIVERED AT SAID PREDETERMINED SPEED ON A TAKE-UP PACKAGE AT A SPEED WHICH IS LESS THAN SAID DELIVERY SPEED SO THAT THE TENSION OF SAID PARTIALLY SET TWIST CRIMPED YARN HAVING HIGH CONTRACTABILITY IS REDUCED, BUT WHICH SPEED IS STILL GREAT ENOUGH TO RETAIN SUBSTANIAL TENSION IN SAID THUS ONLY PARTIALLY TENSIONED PARTIALLY SET FALSE TWIST CRIMPED YARN HAVING HIGH CONTRACTABILITY WHEN THE SAME REACHES SAID TAKE-UP PACKAGE, SO THAT SAID PARTIALLY TENSIONED PARTIALLY SET FALSE TWIST CRIMPED YARN OF HIGH CONTRACTABILITY IS WOUND UP ON SAID TAKE-UP PACKAGE STILL UNDER SUBSTANTIAL TENSION; AND FINALLY SUBJECTING SAID PARTIALLY TENSIONED PARTIALLY SET FALSE TWIST CRIMPED YARN HAVING HIGH CONTRACTABILITY WHILE IT IS WOUND UP UNDER SAID SUBSTANTIAL TENSION ON SAID TAKEIS WOUND UP UNDER GIVEN PERIOD OF TIME TO A SETTING FLUID WHICH COMPLETES THE SETTING OF SAID PARTIALLY TENSIONED PARTIALLY SET FALSE TWIST CRIMPED YARN, THUS OBTAINING A RELAXED FALSE TWIST CRIMPED YARN WHICH HAS ONLY A LOW CONTRACTABILITY OF SUBSTANTIALLY LESS THAN 50%, HAS SUBSTANTIAL DEMENSIONAL STABILITY AND IS SUBSTANTIALLY OF THE NON-TORQUE TYPE WHILE BEING ALMOST AS HIGHLY BULKED AS FULLY TWIST CRIMPED YARN.