US3091912A

US3091912A - Method of processing stretch yarn and yarns produced thereby

Info

Publication number: US3091912A
Application number: US653953A
Authority: US
Inventors: Nicholas J Stoddard; Warren A Seem
Original assignee: Leesona Corp
Current assignee: Leesona Corp
Priority date: 1957-04-19
Filing date: 1957-04-19
Publication date: 1963-06-04
Anticipated expiration: 1980-06-04

Description

June 4, 1963 N. J. STODDARD ETAL 3,091,912

METHOD OF PROCESSING STRETCH YARN AND YARNS PRODUCED THEREBY Filed April 19, 1957 4 Sheets-Sheet 1 FIG. I.

INVENTORS 2 NICHOLAS J. STODDARD WARREN A. SEEM BY WW ATTYS.

June 4, 1963 N. J. STODDARD ETAL 3,

METHQD OF PROCESSING STRETCH YARN AND Filed April 19, 1957 YARNS PRODUCED THEREBY 4 Sheets-Sheet 2 INVEN'I'ORSZ j; NICHOLAS J. STQDDARD WARREN A. SEEM WWW ATTYS.

June 4, 1963 N. J. STODDARD ETAL 3,091,912

METHOD OF PROCESSING STRETCH YARN AND YARNS PRODUCED THEREBY Filed April 19, 1957 4 Sheets-Sheet 3 FIG? NICHQLAS J. STODDARD WAIQREN A. SEEM ATTYS.

INVENTORS June 1963 N. J. STODDARD ETAL 3,091,912

METHOD OF PROCESSING STRETCH YARN AND YARNS PRODUCED THEREBY 4 Sheets-Sheet 4 Filed April 19, 1957 FIG9.

FIG! I.

FIG. I2.

INVENTORS: NICHOLAS J. STODDARD WARREN A. SEEM ATTYS.

3,091,912 METHGD F PROCESSING STRETCH YARN AND YARNS PRODUCED THEREBY Nicholas J. Stoddard, Berwyn, and Warren A. Seem,

(Ihester Springs, Pa., assignors to Leesona Corporation,

a corporation of Massachusetts Filed Apr. 19, 1957, Ser. No. 653,953 31 Claims. (Cl. 57-140) The present invention relates to methods, and prodnets of reprocessing continuous and discontinuous multifilament yarns which are known as textured yarns and which have thermoplastic qualities. The invention has particular application to torque stretch yarns which have been produced by twisting a multi-filament, setting the twist, and reverse twisting. The term torque stretch yarn is used in the specification and claims as a generic term regardless of the amount of torque and stretch actually present in the finished yarn. The present application is a continuation-in-part of our co-pending application, Serial No. 401,803, filed January 4, 1954, now Patent Number 2,803,108.

A primary object of the present invention is to provide a method for producing a yarn having regulated or controlled shape, luster, cross-sectional area, texture, dimensional stability, torque, resilience, residual shrinkage, stretch, recovery from stretch, and elasticity.

Torque stretch yarns are usually classified as stretch yarns because of their characteristic high degree of sensitivity to tensile stress, as for example, with nylon a load of only 0.03-0.04 gram per denier fully extends the yarn to the limit of its stretch characteristics which in many cases is several hundred percent. Torque stretch yarns have been advantageously used for the production of fabrics, such as stretch hosiery, but their sensitivity to tensile stress has been a deterrent to their use in many other fabrics. Such fablics may include certain circular knit fabrics, flat knit fabrics, lace fabrics, and woven fabrics, to name the most common.

Torque stretch yarns manifest certain physical characteristics but also possess certain latent characteristics including the tendency or ability to change in shape, luster, cross-sectional area, torque, resilience, residual shrinkage, texture, elasticity, stretch, recovery from stretch and dimensional stability. These characteristics may become activated and manifest themselves during subsequent operations or storage of the yarn, or the gray or finished fabric formed therefrom.

After textured yarns in general and torque stretch yarns" in particular are fabricated, it is common practice to use various finishing techniques to obtain desirable fabric characteristics. However, in fabric form, the geometry of the fabric and the limitations as to heat and tension that can be effectively applied to the yarns comprising the fabric, very greatly limit the extent to which the manifest physical characteristics of the yarns may be altered and the extent to which the latent characteristics of the yarns may be activated or deactivated. According to the present invention, no such limitations exist since it is possible to apply any desired heat ranging in temperature from ambient to the melting point of the yarns and any desired tension ranging from zero to the breaking point of the yarn in whatever correlation is required to produce the desired effect or effects.

Another deterrent to the use of torque stretch yarns is the fact that during storage of the yarn prior to fabrication of the fabric, the normally manifest characteristics of the yarn become latent. For example, if a torque stretch yarn is Wound on a spool, it loses its manifest bulking characteristics to a degree dependent upon the length of time on the spool. If the yarn is immediately unwound, it manifests high bulking characteristics, but

after a prolonged period, the bulking characteristics become latent and must be activated in order to be manifest. In addition, the position of each yarn section on the spool determines the amount of tension and lateral compression upon it, and since the position varies, some sec tions have different manifest characteristics than other sections. The non-uniform yarn when formed into fabrics may cause streaks or other undesirable irregularities in the fabrics. The present invention overcomes this problem by reprocessing the yarn to uniformly control or regulate its characteristics.

More specifically, the reprocessing of torque stretch yarns in accordance with the present invention is accomplished by subjecting the yarn to controlled degrees of tensile stress with or without correlated heat or both, and with or without additional twisting, untwisting, or false twisting. Preferably, the reprocessing is a continuous operation and may be carried out simultaneously with the initial production of the torque stretch yarn or in a separate operation following the initial production.

All of the objects of the present invention and the various details of the construction and operation of the apparatus and of the performance of the methods are more fully set forth hereinafter with reference to the accompanying drawings in which:

FIGS. 1 and 2 are respectively, front and side views of an apparatus for performing methods of the present invention;

FIGS. 3 and 4 are similar views of another apparatus for performing methods of the present invention;

FIG. 5 is a fragmentary view similar to FIG. 4 at a reduced scale illustrating a modification of the apparatus shown in FIGS. 3 and 4;

FIGS. 6 and 7 illustrate still another apparatus for performing methods of the present invention;

FIG. 8 is an enlarged view showing a multi-filament torque stretch yarn such as is reprocessed by the present invention;

FIG. 9 is an enlarged view of a filament removed from the multi-filament yarn shown in FIG. 8;

FIG. 10 is a view on the same scale as FIG. a yarn processed by another embodiment invention;

FIG. 11 is a view similar to FIG. 9 showing one filament of the yarn of FIG. 10; and,

FIG. 12 is a greatly enlarged view of a filament embodying a uniform, opposed partial spiralled formation which selected embodiments of the present invention tend to produce.

As stated above, the primary object of the invention is to control, alter and regulate the manifest and latent physical characteristics of torque stretch yarns so as to pro duce yarns having the optimum of favorable manifest and latent physical characteristics in the yarn for subsequent yarn operations, for yarn storage, and for fabrication; in the gray fabric for fabric finishing; "and in the finished fabric for the desired end uses.

The invention has various embodiments, and the embodiment which is preferred is dependent upon the yarn characteristics which are desired, and the individual peculiarities of the processors plant.

By one embodiment (A) of theinvention, the object is carried out by traveling the torque stretch yarn through a heated zone under tensile stress, the heat being correlated with the tensile stress upon the yarn. By another embodiment (B) of the invention, the object is carried out by continuously elongating the structural elements of a traveling torque stretch yarn at ambient temperature in one portion of its travel, and in another portion of its travel continuously controlling the tensile stress upon the traveling yarn While continuously traveling 8 showing of the present the yarn through a heated zone under the controlled tension, the heat being correlated with the tensile stress upon the yarn in the second portion of its travel. By another embodiment (C) of the invention, the. object is carried out by. continuously applying heat and correlated yarn tension to torque stretch yarn following its production without interrupting the linear movement of the yarn after the reverse twisting phase of its production. By another embodiment (D) of the invention, the object is carried out by continuously reducing tensile stress upon a torque stretch yarn following its production without interrupting the linear movement of the yarn after the reverse twisting phase of its production and continuously heating the relaxed traveling yarn. By another embodiment (E) of the invention, the object is carried out by continuously elongating the structural elements of a traveling torque stretch yarn at ambient temperature in one portion of its travel, and thereafter continuously reducing tensile stress in the traveling yarn in another portion of its travel and continuously heating the traveling yarn in the second portion of its travel in correlation with the reduced tensile stress. By still another embodiment (F) of the invention, the object is carried out by continually traveling a torque stretch yarn through a heated zone under correlated heat and tensile stress and continually traveling heated and tensioned yarn through a false twist spindle rotating in a direction to cause the yarn to be twisted and reverse twisted in directions opposite to the twist and reverse twist of its production.

The above-listed embodiments of the invention may be carried out continuously with the production of torque stretch yarns, simultaneously or continuously with other normal subsequent yarn operations or as independent operations; with heat and tensile stress being employed to increase or decrease the yarns manifest physical characteristics and/ or activate or further deactivate latent forces or characteristics of torque stretch yarns.

The various embodiments of the invention may be carried out on yarn processing apparatus such as illustrated in FIGS. 1 to 7 of the drawings. In the apparatus shown in FIGS. 1 to 5, the previously processed torque stretch yarn is continuously advanced from the supply package to the takeup package and is capable of being subjected to controlled tension without heat, controlled tension in various degree with correlated. heat, or both in sequence. The apparatus includes a tension device adjacent the supply package, a second tension device in the term of feed rolls following the first tension device, a heater to apply controlled heat to the yarn following the second tension device, and means to positively advance the yarn adjacent the takeup package which cooperates with the second ten- ,sion device to control the tension on the yarn during its travel through the heating device. FIGS. 6 and 7 show one apparatus for originally producing the torque stretch yarn which has applied thereto an additional tension controlling device in the form of feed rolls and an additional heater to apply controlled heat to the yarn prior to delivery of the yarn to the t-akeup package.

. In FIG. 1, yarn Y is ravelled from a supply package 1 of previously processed torque stretch yarn and passed between gates of an adjustable tension device 2, around driven teed rolls 3, through a slot 4 of a heating device 5,

The tension in the yarn may be regulated to any degree by regulating the tension device 2 and the feed rolls 3. The tension device 6 is normally rendered inoperative, but when the feed rolls 3 overfeed the yarn to relax the same as it passes the heating device, the tension device 6 is adjusted to apply sufficient tension in the yarn to enable the traverse guide eye to form a firm package.

' The device may also be used to thermally process raw yarn, in which case a raw yarn package 18 is substituted for the package 1 of torque stretch yarn? Embodiment (A) of the invention may be carried out by the use of the apparatus of FIGS. 1 and 2. With the tension device 2 operative or inoperative, the speed of the iced rolls 3 may be regulated relative to the speed of the taken-p roll a to feed the yarn Y, through the heating device 5 under any desired tensile stress up to the breaking point of the yarn. Likewise, the heating device 5 maybe regulated to heat the traveling yarn to any desired temperature from ambient up to a temperature not substantially greater than the temperature used in setting the stretch characteristics of the torque stretch yarn. The travel of the yarn in the apparatus of FIGS. 1 and 2 may be modified and still be used to carry out embodiment (A) of the invention by utilizing the tension device 2 to apply any desired tensile stress up to the breaking point of the yarn. In this case, the yarn may by-pass the feed roll-s 3.

Embodiment (B) of the invention may also be carried out by the use of the apparatus of FIGS. 1 and 2. The tension device 2 is adjusted to restrain freedom of travel of the yarn to an extent that the structural elements of the yarn are elongated, the tensile stress upon the traveling yarn is thereafter controlled by regulating the speed of the feed rolls 3 in relation to the speed of the takeup rolls 9, and the temperature of the heating device 5 is adjusted to heat the yarn to a temperature in any correlation with the tensile stress upon the yarn traveling therethrough.

Embodiment (E) of the invention likewise may be carried out by the use of the apparatus of FIGS. 1 and 2. The tension device 2 is adjusted to restrain freedom of travel of the yarn to an extent that the structural elementsofthe yarn are elongated. The speed of the feed rolls 3 in relation to the speed of the takeup rolls 9 is adjusted so that tensile stress is reduced in the traveling yarn during its travel through the heating device.

In utilizing the apparatus of FIGS. 3 and 4, several strands of yarn Y' are ravelled over the ends of supply packages 20 of previously processed torque stretch yarn, are passed into engagement with tension devices 22 through stop motion drop eyes 21, through a gathering eye 23, around driven feed rolls 24, through thread separator 25, through the slot 26 of a heating device 27,

through a second thread separator 28 against a revolving through another tension device 6; then through a traverse guide eye 7, and finally onto a takeup package 8, which is driven by a takeup roll 9. The

rolls

9 and 3 are driven independently as indicated at 11 and 12 respectively, so that thespeeds may be regulated, for example, by

speed regulators

14 and 15. The temperature of the heating device 5 may be regulated to heat the yarn to any temperature above ambient that is desired, for example by regulating the voltage applied thereto as indicated at 16 in response to a thermostat 17 in the heater. The'voltage is therefore regulated compensatively with the rate of heat transfer to the traveling yarn and ambient temperature to uniformly heat the yarn to the desired degree.

oiling roll 30, through a gathering eye 29, around feed rolls 3-2, through a centering eye 33, then through a ring traveler 34 which imparts twist to the yarn, and finally the twisted yarn is wound onto a take-up spool 35. In the alternative, a filling-wind type of take-up shipping package may replace spool 35. This apparatus provides for the reprocessing of a plurality of strands of torque stretch yarn which are continuously plied and twisted together. The

feed rollers

24 and 32 are driven independently as indicated at 36 and 37 and their speed is regulated by speed regulating devices indicated at 38 and 39. Likewise, the temperature in the heater 27 may be egulated compensatively with the rate of heat transfer ample as indicated at 42 and the speed of rotation may be regulated by a speed regulator 43. When using the feed rolls 41, it is then practical to ravel the yarn from the side of the packages 26 which are rota-table on the creel 4-4 as shown in FIG. 5. Otherwise, the apparatus of FIG. 5 is identical to that of FIGS. 3 and 4, and the yarns are ravelled from the packages 20', through the stop motion drop eyes 21', over the feed rolls 41 and 24, and through the rest of the apparatus as described above in connection with FIGS. 3 and 4.

Embodiment (A) of the invention may be carried out by the use of the apparatus of FIGS. 3-5. Any desired tensile stress up to the breaking point of the yarn may be applied to the yarn passing through the heating device 27 by the tension device 22 or by regulating the speed of the feed rolls 24- or 41 in relation to the speed of the feed rolls 32, with the temperature of the heating device 27 adjusted to heat the yarn to any temperature from ambient up to a temperature not substantially greater than the temperature employed to set the stretch characteristics in the torque stretch yarn.

Embodiment (B) of the invention may also be carried out by the use of the apparatus of FIGS. 35. The tension device 22 or the rolls 41 are controlled in speed to restrain freedom of travel of the yarn to an extent that the structural elements of the yarn are elongated; the tensile stress upon the traveling yarn through the heating device 27 is controlled by regulating the speed of the feed rolls 5.4 in relation to the speed of the feed rolls 32; and the temperature of the heating device 27 is adjusted to heat the yarn to a temperature in any desired correlation with the tensile stress upon the yarn traveling therethrough.

Embodiment (E) of the invention may also be carried out by the use of the apparatus of FIGS. 3-5. The tension device 22 is adjusted or the rolls 41 are controlled in speed to restrain freedom of travel of the yarn to an extent that the structural elements of the yarn are elongated and the speed of the feed rolls 24 in relation to the feed rolls 22 is adjusted so that tensile stress is reduced in the traveling yarn during passage through the heating device 27.

FIGS. 6 and 7 of the drawings diagrammatically illustrate one conventional false twist apparatus for the production of torque stretch yarns with added components to make possible the processing of torque stretch yarn by the invention continuously with its production. In utilizing the apparatus of FIGS. 6 and 7, torque stretch yarn is produced by a false twist method, comprising the steps of ravelling raw yarn Y" from a producers package 46 and passing it through a centering eye 47, in engagement with a disc tension 455, around feed roll 49, through a slot 50 in a heating device 51, up through a revolving false-twist spindle 52 and around the exit roll 53 on the false twist spindle 52 from which the yarn emerges as a torque stretch yarn. In the prior apparatus, the yarn would travel from the exit roll 53 directly to a traverse guide eye 59 and then onto a takeup package 60, but by the present invention, the torque stretch yarn, after leaving the exit roll 53, is passed around feed rolls 54, through a slot 56 of a second heating device 57, through a winding-tension device 53, then over a traverse guide eye 59 and finally onto takeup package 66. In accordance with certain embodiments of the present invention, it may be desired to process torque stretch yarn on this apparatus. In this case, a package 62 of torque stretch yarn is substituted for the package 46 of raw yarn.

The speed of the yarn through the heater 57 is controlled by the speed of the takeup package 60 which is driven by the takeup roll 61 by means of a driving device 65 having suitable regulating means, for example, as indicated at 66. The amount of false twist inserted in the yarn is regulated by regulating the speed of the traveling belt 67 driving the false twist spindle 52, which in turn is controlled as to speed by a motor 68 having a speed regulator 69 incorporated therewith. The tension on the yarn as it is false twisted is controlled by controlling the speed of the feed rolls 49 in relation to the speed or" feed rolls 54 as for example by motors 71 and 74 having

speed regulators

72 and 75 respectively, and by controlling the tension in the disc tension 48. The amount of heat imparted to the twisted traveling yarn is controlled by regulating the energization of the heater 51, for example by a regulator 73 which is responsive to a thermostat 73a. In the present instance, the speed of the yarn through the false twist spindle is regulated by regulating the speed of the feed rolls 54-. The feed rolls 54 are driven independently, for example by a motor as indicated at 74 having a speed regulating device 75 incorporated therewith. The tension on the yarn traveling through the heater between the feed rolls 54 and the tension device 53 is controlled by regulating the relative speeds of the driving devices 65 and '74. The tension device 58 controls the wind-up tension in the usual manner, and may be replaced by tension-controlling feed rolls, if desired. Likewise, the heat applied to the yarn by the heater 57 is controlled compensatively by controlling the energization of the heater 57, for example by a regulator 76 responsive to a thermostat 76a.

Embodiment (C) of the invention may be carried out by the use of the apparatus of FIGS. 6 and 7. The processed torque stretch yarn traveling upwards from the exit roll 53 is under normal tensile stress required for the production of the particular yarn but by adjusting the speed of the takeup roll 61 in relation to the speed of the feed rolls 54, any desired tension is applied to the yarn and the temperature of the heating device 57 is adjusted to obtain any correlation of heat and tension desired in the traveling yarn.

Embodiment (D) of the invention may also be carried out on the apparatus of FIGS. 6 and 7. The processed torque stretch yarn traveling upwards from the er' t roll 53 is under normal tensile stress required for the production of the particular yarn but by adjusting the speed of the takeup roll 61 in relation to the speed of the feed rolls $4, tensile stress is reduced in the yarn and the relaxed yarn is heated as it travels through the heater 5'7.

Embodiment (F) of the invention may also be carried out on the apparatus of FIGS. 6 and 7. When the apparatus is so used, the yarn from the package 62 of torque stretch yarn is substituted for the package 46 of raw yarn and the feed rolls 54, the heating device 57 and the winding tension device 58 are not used. The yarn is traveled through the heating device 51 and the thermostat 73a is adjusted to cause the heater to heat the yarn to the desired temperature and tensile stress is applied to the yarn by adjusting the speed of the feed rolls 4a in relation to the speed of the takeup roll til. The yarn is traveled through the false twist spindle 52 and around the exit roll 53, the spindle rotating in a direction to oaust the yarn to be twisted and reverse twisted oposite to the twist and reverse twist of its production. Then the yarn is traveled through the guide eye 59 and onto takeup package 66*.

Embodiments (A), (B), and (E) of the invention may also be carried out by the use or" the apparatus of FlGS. 6 and 7 in the same manner as previously pointed out with respect to the use of the apparatus of FIGS. 1 and 2 by by-passing the false twist spindle and maintaining the heater 51 de-energized.

Multi-filament torque stretch yarns are conventionally produced by three basic operations, the first being the twisting of the multi-filament yarn which causes each individual filament to twist on its own axis and twist or spiral as a helix about the other filaments of the group. Unless the multi-filament yarn is cold drawn while being so twisted, the second operation involves heat setting of the yarn, but in either cold drawing or heat setting, the molecules or structural elements of each individual filament of the yarn are reoriented to the twisted and spiralled shape according to the accepted theory of super positioning. As a result of the reorientation, the new spiralled and twisted formation of the filaments become inherently permanent. The third step involves the twisting of the yarn in the opposite direction. Depending upon the degree of reverse twisting in relation to the initial twisting, the reverse twisting reduces or eliminates the extent to which each filament is wrapped about the others and physically holds the group in a compact unit.

Normally when such yarns are partially relaxed or relieved of tensile stress, each filament has a tendency to return to its super-positioned spiralled shape but is prevented from so doing by the torque forces resulting from thereverse twisting. These torque forces are in a direction opposite to that which would cause the spiralled formations to tighten and become of less amplitude or diameter, but rather these torque forces increase the amplitude or diameter of the spiralled formations.

As a result, some of the spiralled formations accommodate or adjust themselves to the torque by springing into two partially spiralled formations of opposite direction with adjacent spirals assuming opposite directions.

This opposed spiral formation is illustrated in FIG. 12 which represents a filament 7 8 of a multi-filament stretch yarn which has been partially relaxed after production. Referring to FIG. 12, the filament 78 has been subdivided into a plurality of sections indicated respectively at a and b by the broken lines shown therein. The section a of the filament 78 comprises a partial spiral in a Z direction. The section b, on the other hand, comprises a partial spiral in the 8 direction. The loop portions be tween the sections a and b are the result of the change from the S spiral to the Z spiral and vice versa.

To illustrate this principle, a person may take an expandable telephone cord which consists of a plurality of convolutions in helical form. This is analagous to a single filament of a multifilament stretch yarn after the initial twisting operation and subsequent setting operation. The reverse twisting operation may then be performed on the cord, and if sufficient tension is applied, the cord assumes a substantially straight condition. However, as the cord is relaxed, or if insufficient tension is applied, certain convolutions of the Z spiral spring into an S spiral, and the cord approaches the formation illustrated in FIG. 12.

Following the formation of opposed spirals, as the torque stretch yarn and its filaments are further relaxed, the torque forces cause groups of opposed spiralled formations to twist about themselves and pigtail to a degree where the resistance to further twisting is greater than the torque forces present, and as a result, neighboring spiralled and opposed spiralled formations twist about themselves and pigtail and so on at random throughout the length of the filaments of the yarn. This occurs randomly at the points offering the least resistance.

The variations in resistance to being deformed are primarily due to resistance offered by abutting filaments of the group which form the multifilament yarn, and variations in amplitude or diameter of the spiralled formations of the filaments resulting from the location of each 7 individual filament relative to the center of the yarn. This relative location of a selected filament at any given point along the length of the yarn during the initial twisting in the production of the torque stretch yarn, determines how many filaments of the mu-ltifilament yarn the selected filament spirals about. The number of filaments it spirals about, in turn, determines the amplitude or diameter of the spiral in the selected filament at the given point. For example, at one point in the yarn, a selected filament may lie in the exact center of the yarn. At this point, the selected filament would not spiral about any other filaments, but would only twist on its axis, the spiral thereby having zero amplitude or diameter. At a they are latent.

second point, the selected filament may lie on the outer periphery of the yarn. At this second point, the selected filament would spiral about every other filament in the yarn and its spiral at the second point would have maximum amplitude or diameter. Normally, a selected filament will be found in various relative locations along the length of the yarn.

The random pigtail-ing can be observed in the above illustration using a telephone cord by allowing the cord to relax further, in which event the opposed spiral formations form pigtails and create a generally tangled mass of wire.

Thus, with normally relaxed torque stretch yarn, the group of substantially parallel filaments of the raw yarn is converted into a group of filaments having at random and of various magnitudes, spiralled formations in one direction, opposed partially spiralled formations, spiralled formations in the opposite direction, and groups of opposed spiralled formations twisted about themselves or pigtailed. These formations shorten the yarn and increase the area of the cross-section (bulk). Furthermore, these formations straighten under very little tensile stress and their effective length is increased as the yarn is stretched. This characteristic gives the yarn its so-called stretch characteristic.

The aforesaid irregular formations of the filaments comprising the torque stretch yarn is inherent to the yarn per se as well as in the yarn embodied in the fabrics made therefrom. By certain embodiments of the present invention, if desired, the irregular formations may be changed into a pattern of substantially uniform opposed partially spiralled formations of reduced and uniform magnitude and increased fiequency as illustrated in FIGS. 10 to 12 of the drawings.

Referring to FIGS. 8 to 12 of the drawings, FIG. 8 illustrates a torque stretch yarn immediately following its production and when it has been allowed to relax. It will be observed that the filaments 81 composing the yarn exhibit pigtailed formations and the yarn has a generally irregular outline. FIG. 9 illustrates one of the filaments 81 shown in FIG. 8 at an enlarged scale. FIG. 10 illustrates a yarn 82 which may be produced by certain embodiments of the present invention. It will be observed that the individual filaments 83 making up the yarn 82 of FIG. 10 do not exhibit the pigtailed formations apparent in FIGS. 8 and 9, and the yarn 82 as a whole, has less bulk than the yarn 80. FIG. 11 illustrates an individual filament 83 removed from the yarn 82 of FIG. 10 and demonstrates that the pigtailed formations have been eliminated. Further examination under increased magnification of the filament shown in FIG. 11, reveals that the filament 83 approaches the regular opposed partially spiralled formations shown at 78 in FIG. 12.

Immediately after the processing of the raw yarn to form torque stretch yarn, the yarn so produced normally exhibits the tendency to relax into the condition shown at 80 in FIG. 8. Thus, the stretch characteristics of the yarn are manifest. However, after the yarn has been wound on a package under tension and is stored for a period of time, the stretch characteristics of the yarn become latent, and when the yarn is unwound from the package under minimum tension, the torque forces in the yarn are not suflicient to cause the yarn to shorten and assume the random pigtailed and irregular formations exhibited by a freshly produced yarn. The tendencies are present in the yarn, but instead of being manifest, The latent tendencies may be made manifest by heat or tension.

The uniformity in the spiral formations is accomplished by subjecting the yarn to uniform correlated heat and tensile stress. The heat activates both the latent tendency of the filaments to assume spiralled formations and the opposed torsional forces and also makes the filaments more pliable so as to ofier less resistance to the accommodation and equalization of the torque forces by Dartial spirals formed alternately in opposite directions. The yarn tension acts to prevent groups of spiralled or partially spi-ralled formations from twisting about themselves and forming pigtails to relieve the torque forces.

Of course, perfection is never attainable and consequently, it is not possible to attain by the invention a yarn whose every filament has precisely every other deformation of the same magnitude and partially spiralled in opposed directions as shown at a and b in FIG. 12. However, the various degrees of change towards perfection are such that a wide range of numerous distinctly different yarns result. For example, the present invention makes possible yarns ranging in shape: from irregular to very uniform, in luster: from high to low, in crosssectional area: several hundred percent, in torque of the group of filaments: several hundred percent, in resilience: low to high, in residual shrinkage: several hundred percent, in texture: rough to smooth, in elasticity: fair to good, in stretch: several hundred percent, in recovery from stretch: good to very good, and in dimensional stability: low to very high. It is to be pointed out that although the bulk or cross-sectional area of the torque stretch yarn so processesd may be greatly reduced in the yarn per se, the latent forces of the yarn cause the processed yarn in the fabric after finishing, to have greater bulk than possible with conventional torque stretch yarn. It is noted that the characteristics listed above cannot be varied entirely independently of one another since changing certain of the above characteristics, effects changes in other characteristics. Thus, to obtain a suitable yarn for the desired purpose, the tension and heat are regulated to produce the dominant characteristics which are deemed necessary, and the unimportant characteristics are more or less disregarded.

Torque stretch yarns generally manifest a very high degree of stretch and recovery immediately after the reverse =twisting phase of their production. This stretch and recovery may be up to over 400%. Unless wound into a skein and freely relaxed, such yarns, when stored upon their yarn packages, lose much of their manifest stretch and recovery characteristic. The degree of the loss for a given yarn depends primarily upon the tensile stress load upon the yarn 'in the package and the length of time of storage.

The maximum loss in the manifest stretch and recovery characteristic of a given yarn occurs when the yarn in the package is wound and stored under the tensile stress necessary to extend the yarn stretch characteristics, i.c. suiiioient stress to just straighten substantially all of the variously spiralled and twisted deformations without elongating the structural elements of the filaments themselves.

When the same yarn is stored under a greater stress load below the tensile stress necessary to extend the yarn to its yield point, i.e., the point where the structural elements are elongated beyond their elastic limit and the yarn markedly yields so as to be permanently elongated, the stress temporarily elongates the structural elements of the yarn, and the elastic recovery of the yarn occur ing as the load is removed upon raveling the yarn from the storage yarn package, mechanically activates the inherent torsional forces and manifests the tendency of the filaments to assume spiralled formations. The greater the extent of the recovery from stretch of the structural elements of the yarn, the greater is the aforementioned activating action.

In all yarn packages (except freely suspended and relaxed skeins, and it is not practical to fabricate from skeins), the stress upon the yarn comprising the packages varies considerably throughout the package. In commercial production, the length of time of package storage before fabrication also varies considerably. Consequently, the torsion and the degree of the tendency of the filaments to assume spiralled formations varies accordingly.

Torque stretch yarn processed under embodiments A, B, C, and F of the invention do not have these objectionable characteristics. Thus, by reprocessing the stretch yarn in accordance with the present invention, it is possible to impart to the yarn from each package, uniform characteristics of the type desired. Furthermore, yarns from packages which have been stored for varying lengths of time may be reprocessed to produce identical characteristics. Thus, when using reprocessed yarns from several packages, the characteristics of all the yarns are uniform and there is no possibility of streaks or other imperfections appearing in the fabric by reason of changes from one package to another. Thus, the present invention provides means for equalizing the characteristics of the yarn regardless of the length of time it has been stored and the tension with which it has been wound.

The effect of tension alone, heat alone and heat and corrrelated yarn tension upon torque stretch yarn may be observed by the few simple experiments A-E below:

EXPERIMENT A Ravel by hand a multi-filament torque stretch yarn from a normal package that has been standing for some time and observe that the shape of the yarn and its bulkiness varies considerably. Stretch the yarn lightly until resistance to stretching is just felt and then relax the yam, observing that the yarn exhibited little stretch and recovery. This stretching extended the yarn to the limit of its stretch characteristics. Typically, the stretch might be 45%. Then stretch the yarn vigorously beyond the point where resistance is felt and permit it to relax, 0bserving that the shape and bulkiness now becomes relatively uniform and the stretch and recovery is greatly increased and the yarn is somewhat similar to that shown at 8i in FIG. 8. This stretching extended the yarn beyond the limit of its stretch characteristics, but would not exceed the yield point of the structural elements. Typically the stretch might be 140%. It is noted that the greater the tensile stress up to the yield point of the structural elements of the filaments, the greater is the activation of the "dormant or latent forces.

EXPERIMENT B Ravel yarn by hand from the same package of multifilament torque stretch yarn as used in Experiment A above. Gently heat a relaxed length of the yarn over an electric hot plate or other heating element and observe that the yarn shrinks or shortens to give it a high degree of stretch and recovery and the yarn is somewhat similar to that shown at 34 in FIG. 8. Typically it might be 270%. It is to be noted that heat alone as used in this experiment, causes the torque stretch yarn to attain substantially more stretch and recovery than that attained by the use of yarn tension alone as used in Experiment A above. It is noted that the higher the heat up to about 10 less than the temperature used to produce the yarn, the greater is the activating of the latent forces.

EXPERIMENT C Heat gently over an electric hot plate, the relaxed length of multi-filament torque stretch yarn which has been vigorously stretched in Experiment A above. Observe that the yarn shrinks or shortens and attains a greatly increased stretch and recovery and is somewhat similar to that shown at in FIG. 8. Typically it might be 330%. It is noted that torque stretch yarn which has first been stretched and thereafter heated, attains a greater degree of stretch and recovery than torque stretch yarn that has been heated only.

EXPERIMENT D Again using multi-fila-ment torque stretch yarn, from the same package as used in Experiment A above, heat gently over an electric hot plate variously tensioned lengths of yarn. Observe that the yarn attains various greater degrees of dimensional stability depending upon the tension upon the yarn being heated. The stretch and recovery is likewise reduced variously down to as low as only a few percent. FIG. 10 shows a yarn 82 with good dimensional stability and low stretch. It is noted that heat and yarn tension must be correlated since manifest and latent forces may be activated at a given temperature and yarn tension, but deactivated if either the temperature or yarn tension is increased. An increase in temperature reduces the yield point of the yarn and permits the molecules or other structural elements of the filaments to be reoriented by the unchanged yarn tension. In addition, increased yarn tension by itself is sutficient at the unchanged temperature to cause the yarn to manifest the latent characteristics and effect superpositioning of the formations of the filaments.

EXPERIMENT E Separate one of the filaments of the yarn of Experiment D and the yarns of Experiments A, B, and C and observe that the filaments of the yarns of Experiments A, B, and C have an irregular pattern of comparatively infrequent and high magnitude or amplitude spirals, partial spirals and twisted deformations, for example as shown at 81 in FIG. 9, whereas the filaments of the yarns of Experiment D have a uniform pattern of opposed partially spiralled formations of greatly increased frequency and greatly reduced magnitude or amplitude, for example as shown at 83 in FIG. 11.

With the above experiments in mind, it is apparent that various results may be obtained by the application of heat and tension to the yarn. As pointed out above, the ef fect of combined heat and tension is not the same as the effect of tension and heat applied in sequence.

Various possibilities afforded by the present invention are indicated by the various examples which follow. These examples are not exhaustive of the possibilities afforded by the invention, but are exemplary of the objects which are to be obtained by the invention.

Example I The object is to produce a 70 denier O filament Dacron Weaving yarn from a 70 denier 5O filament Dacron torque stretch yarn. For best results, a weaving yarn to be used either in the warp or filling should have stability of its dimensions and shape so that normal tension variations of warping and weaving cause no material change in the length, cross-sectional area or shape of the yarn. If they are not eliminated, changes in dimensions of the yarn cause warp or filling streaks in the fabric or variations in the texture of the fabric. Also, it is desirable that warp and filling yarns per se have the maximum straightness and density to facilitate the fabrication. Any desired changes in shape or cross-sectional area of the yarn should take place after the fabric is woven and during subsequent finishing operations. The aforesaid desirable characteristics of warp and filling yarns for weaving are not possessed by normal multifilament torque stretch yarns, but by the present invention, these characteristics may be induced to manifest themselves in the yarn.

The process is carried out by utilizing the apparatus of any of FIGS. 1 to 7 whereon the aforesaid 70 denier torque stretch yarn is traveled at a yarn tension of 2 grams through the heated zone to heat the yarn to 400' degrees F. After this processing, the extensibility of the yarn under normal variable Warp and weaving tensions is reduced from up to 300% to about 3%. The yarn greatly increases in straightness under the variable war-ping and weaving tensile stresses. In addition, the filaments assume a more compact relationship to produce a more dense yarn, such as shown at 82 in H6. 10.

When the yarn which has been processed in this man- 12 ner'is woven into a fabric and the fabric is finished in the usual manner, the finished fabric has many advantages over fabrics produced with torque stretch yarns not processed. For example, the luster of the yarn after finishing is reduced, thereby reducing the sheen of the fabric. The cross-sectional area or bulk 'of the yarn is increased in the subsequent finishing operations, thereby contributing to increased opacity in the fabric. The torque forces in the yarn are reduced and more uniformly distributed along the length, thereby reducing the tendency of the fabric to bias. The residual shrinkage of the yarn is reduced which reduces the residual shrinkage in the fabric. The frequency of the filament deformations is increased which results in a finer texture in the finished fabric and contributes to the increased opacity thereof. The resilience of the yarn is increased; the clasticity of the finished fabric is increased; the stretch is reduced; and the recovery from stretch is increased which cooperate to provide good crease-resistance in the fabric.

Example 11 The object is to produce a 40 denier 13 filament nylon yarn for tricot knitting from a 40 denier 13 filament nylon torque stretch yarn. Torque stretch yarns have generally been unsatisfactory for tricot knitting due to the stretch characteristics of the yarn, the bulkiness of the yarn per se and the lack of uniformity of the yarn in the warps and as it is raveled from the storage package. All of these factors cause ditficulties in warping and knitting and produce defects in the knitted fabric.

In producing the yarn, 40 denier l3 filament torque stretch yarn is processed on any apparatus of FIGS. 1 to 7 of the drawings. The yarn is elongated to activate its dormant forces by applying a yarn tension of grams, then the yarn tension is reduced and maintained at 4 grams as the yarn is heated to a temperature of 360 degrees F. The resultant yarn is similar to that shown in FIG. 10, possessing excellent dimensional stability, being compact and uniform as raveled from its storage package and in the warp and producing uniform knitted fabric.

Example III The object is to produce a no torque yarn'for single carrier full fashioned knitting from a 30 denier l4 filament nylon torque stretch yarn continuously with the reverse twisting phase of the yarns production. When using torque stretch yarn for single carrier full fashioned knitting, it has been necessary to use a two ply yarn composed of one ply with torque in one direction and the second ply with torque in the opposite direction so that the stocking knit therefrom would not tend to twist on a bias. By tending to balance the partially spiralled sections as shown in FIG. 12, it is possible to equalize the overall torque in a torque stretch yarn. Therefore, it is not necessary to use a yarn balanced by plying.

This process is accomplished by utilizing the apparatus of FIGS. 6 and 7. The processed 14 filament 3O denier nylon torque stretch yarn, as it is reverse twisted upon leaving the exit roll 53, is continuously traveled about the feed rolls 54 and through the heater 57 with the speed of the feed roll 54 and the takeup roll 61 so adjusted that 60 grams of tension is applied to the yarn at 350 degrees F. The resultant yarn is similar to that shown at82 in FIG. 10, and when knitted into a stocking and finished, produces a stretch stocking that does not twist on a bias. 7

Example IV The object is to produce a torque stretch yarn having a high degree of extensibility continuously with the reverse twisting phase of the production.

This procedure is accomplished by utilizing the appar-atus of FIGS. 6 and 7 with unprocessed 70 denier, 34 filament nylon yarn on the package 46. Processed torque stretch yarn is produced by the heater 51 and spindle 52, and as it is reverse twisted upon leaving the exit roll 53, the yarn is continuously traveled around the feed rolls 54 and through the heating device 57 with the speed of the feed rolls 54 and the takeup roll 61 so adjusted that the yarn travels under substantially no tensile stress through the heating device 57 which is adjusted to heat the yarn to 430 degrees F. For example, the rolls 54 may overfeed substantially relative to the rolls 61. The relaxing of the yarn prior to heating permits the yarn to bulk and the relatively high temperature causes further intensification of the filament deformations and twisting upon themselves or pigtailed which become superpositioned. The yarn molecules or structural elements are set in the deformed state and the yarn is similar to but exaggerated over that shown at 80 in FIG. 8 and has high bulk and great extensibility which is not substantially aifected by storage on the package 60.

Example V The object is to produce a torque stretch yarn having maximum bulk in the yarn per se and a minimum residual shrinkage of the components of the yarn.

This object may be accomplished by utilizing the apparatus of FIGS. 1 and 2 wherein tensile stress approximately that of the yield point of the yarn is applied to a 70 denier 34 filament traveling nylon torque stretch yarn by the adjustment of the tension device 2 to thereby activate the latent characteristics. As the yarn leaves the feed rolls 3, all tensile stress is removed from the yarn by overfeeding, then as the yarn passes through the heating device 5, it is heated to a temperature above the temperature employed to set the stretch characteristics of the yarn. For example, with nylon, it is heated to just below the melting point of nylon which is about 480 degrees F. The stretching of the yarn is approximately to the yield point and the immediate removal of tensile stress, activates the latent forces of the yarn to cause it to increase in bulk. The very high temperature to which the fully relaxed yarn is heated, causes further bulking and causes the structural elements of the yarn to shrink and become set. The yarn produced and processed in this manner is similar but exaggerated over that shown at 80 in FIG. 8, but is uniform along its length, and has maximum bulk, minimum torque and minimum residual shrinkage.

Example VI The object is to produce a no-torque yarn from a torque stretch yarn. This object may be accomplished by the use of the apparatus of FIGS. 6 and 7 with the heating device 57 de-energized. A 70 denier 34 filament nylon torque stretch yarn which was originally produced by twisting 70 turns per inch Z, setting the yarn at 435 degrees F. and then reverse twisting 70 turns per inch 8 on a package '62, is placed on the machine. The torque stretch yarn from the package 62 is passed through the apparatus and the motor 68 is controlled to impart 50 turns per inch 8 to the yarn between the exit roller 53 and the rolls 49. The tension on the yarn is regulated to 30 grams and the heater is energized to heat the yarn to 450 degrees F. After the yarn passes the exit roller 53, it is reverse twisted 50 turns per inch 2 and collected on the takeup spool 60. The yarn on the spool 60 is uniform along its length, exhibits an absence of torque accompanied by high bulk and is similar to that shown at 80 in FIG. 8. The yarn so produced may be fabricated without plying and the resulting fabric has no tendency to bias.

The above experiments and examples show that it is possible to produce many varied characteristics in torque stretch yarn by the application of tension and correlated heat, either above or below or at the yield point of the structural elements of the yarn. The heating with correlated tension of the yarn may be preceded or followed by the application of tension above, below, or at the yield point of the yarn. In certain embodiments of the inven- 14 tion, the torque stretch yarn may also be false twisted during the application of heat and correlated tension.

In the foregoing examples, the temperature in the processing may be controlled to be below or above the temperatures to which the fabric is subjected in subsequent finishing operations. When desired, and when the temperature is below that of the finishing operation, the properties which are manifest in the yarn prior to finishing may be superseded by the latent properties which are activated when finishing the fabric. For example, a reprocessed yarn having low cross-sectional area or bulk and low stretch after finishing may have high cross-sectional area or bulk, and high stretch. However, the effect of the reprocessing is present and provides a yarn which is bulkier than the bulk yarn prior to reprocessing or a yarn which has greater stretch than the stretch yarn prior to reprocessing. Thus, the reprocessing of the present invention may induce characteristics in the yarn of the finished fabric which are not present in non-reprocessed torque stretch yarn.

It has been found that in reprocessing torque stretch yarn, it is possible to control the physical characteristics in the reprocessed yarn by controlling the degree of tension in the travelling in at least one portion of its continuous travel, heating the yarn during said portion of its continuous travel to a temperature not substantially greater than the temperature originally used in setting its stretch characteristics, and correlating and controlling tension and heat imparted to said yarn with (1) the tensile stress necessary to extend the yarn stretch characteristics, (2) the tensile stress necessary to extend the yarn to the limit of the yarn stretch characteristics, and (3) the tensile stress necessary to extend the yarn to the yield point of the structural elements of the yarn.

Various tensile stresses may be correlated with heat to produce various physical characteristics. For example, with torque stretch nylon, tensile stress below that necessary to extend the yarn stretch characteristics produces a reprocessed yarn with the optimum of stretch and re covery from stretch; tensile stress above that necessary to extend the yarn stretch characteristics and below that necessary to fully extend the yarn to the limit of the yarn stretch characteristics produces a reprocessed yarn with the optimum of bulk in combination with fineness of texture; tensile stress equal to that necessary to extend the yarn to the limit of its stretch characteristics produces a reprocessed yarn of optimum of bulk in combination with dimensional stability; tensile stress above that necessary to extend the yarn to the limit of its stretch characteristics and below the yield point of the structural elements of the yarn produces a reprocessed yarn with the optimum of bulk in combination with stretch and recovery from stretch; tensile stress equal to the yield point of the structural elements of the yarn produces a reprocessed yarn with the optimum of bulk; and tensile stress above the yield point of the structural elements of the yarn produces a reprocessed yarn with the minimum of torque. In all cases the heat imparted determines the degree of superpositioning of the deformations of the individual filaments.

In the attached drawings, certain conventional elements of the apparatus has been illustrated diagrammatically. In addition, the drives to the various driven components have been shown as separate motors. In actual practice, the apparatus is driven from a common prime mover and variations are obtained by the use of change gears or the like.

While particular embodiments of the present invention have been set forth herein, it is not intended to limit the invention to such disclosure, but changes and modifications may be made therein and thereto within the scope of the following claims.

We claim:

1. The method of processing multifila-ment torque stretch yarn whose stretch characteristics have been set at a given temperature comprising the steps of continuously advancing the yarn, controlling the degree of tension in 1 5 said travelling yarn in at least one portion of its continuous travel, said tension being below the breaking tension of the structural elements of the yarn, heating said yarn during said portion of its continuous travel to a tempera ture not substantially greater than said given temperature and correlating the controlled tension and the heat im par-ted to said yarn with the tensile force necessary to extend the yarn to the limit of its stretch characteristics and the tensile force necessary to extend the yarn to the yield point of the structural elements of the yarn to thereby control the physical characteristics in the reprocessed yarn.

2. A method according to claim 1 wherein the tensioning and heating step-s are correlated below the tensile stress necessary to extend the yarn stretch characteristics.

3. A method according to claim 1 wherein the tensioning and heating steps are correlated above the tensile stress to extend the yarn stretch characteristics and below the tensile stress necessary to extend the yarn to the limit of its stretch characteristics.

4. A method according to claim 1 wherein thetensioning and heating steps are correlated at the tensile stress necessary to extend the yarn to the limit of its stretch characteristics.

5. A method according to claim 1 wherein the tensioning and heating steps are correlated above the tensile stress necessary to extend the yarn to the limit of its stretch characteristics but below the yield point of the structural elements of the yarn.

6. A method according to claim 1 wherein the tensioning and heating steps are correlated at the yield point of the structural elements of the yarn.

7. A method according to claim 1 wherein the tension ing and heating steps are correlated above the yield point of the structural elements of the yarn.

8. A method according to claim 1 wherein the heat applied to the yarn is correlated to the temperature to which the yarn is to be subjected in subsequent fabricfinishing operations.

9. A method according to claim 1 including the addi tional step of controlling the tension in said yarn in another portion of its travel prior to said one portion relative to the tensile force necessary to extend the yarn to the limit of its stretch characteristics and the tensile force necessary to extend the yarn to the yield point of said yarn at ambient temperature, said tension being below the breaking tension of the structural elements of the yarn, to thereby activate latent characteristics of said yarn prior to its travel in said one portion.

10. A method according to claim 9 wherein said yarn in said prior portion of its travel is tensioned at the tensile stress necessary to extend the yarn to the limit of its stretch characteristics.

11. A method according to claim 9 wherein said yarn in said prior portion of its travel is tensioned above the tensile stress necessary to extend the yarn beyond the limit of its stretch characteristics, and below the yield point of the structural elements of the yarn to thereby temporarily slightly elongate the structural elements of the yarn.

l2. A method according to claim 9 wherein said yarn in said prior portion of its travel is tensioned at the yield point of the structural elements of the yarn to thereby temporarily substantially elongate the structural elements 7 of the yarn.

13. A method according to claim 9 wherein said yarn in said prior portion of its travel is tensioned above the yield point of the structural elements of the yarn to thereby permanently elongate the structural elements of the yarn.

14. A method according-to claim 9 wherein the heat applied to the, yarn is correlated to the temperature to which the yarn is to be subjected in subsequent fabricfinishing operations.

15. The method of producing multifilament torque stretch yarn having controlled physical characteristics comprising the steps of twisting a multifilament yarn having thermoplastic qualities in one direction, heating said twisted yarn to a given temperature under correlated ten sion to preclude ductility and thereafter cooling the same toyarn-set the filaments in the twisted formation, continuously advancing said heat-set yarn, twisting said advancing yarn in the opposite direction in one portion of its vtra'vel to impart active torsional forces therein, continuously controlling the tension in the advancing yarn in an other portion of its travel, said tension being below the breaking tension of the structural elements of the yarn, and heating said yarn to a temperature not substantially greater than said given temperature during said other portion of its travel, and correlating the controlled tension and the heat imparted to said yarn with the tensile force necessary to extend the reverse-twisted, heat-set yarn to the limit of its stretch characteristics and the tensile force necessary to extend the yarn to the yield point of the structural elements of the yarn to thereby control the physical characteristics of the multifilament yarn.

16. A method according to claim 15 wherein the tensioning and heating steps during said other portion of the y-arns travel are correlated below the tensile stress necessary to extend the yarn stretch characteristics.

17. A method according to claim 15 wherein the tensioning and heating steps during said other portion of the yarns travel are correlated above the tensile stress necessary to extend the yarn stretch characteristics and below the tensile stress necessary to extend the yarn to the limit of its stretch characteristics.

18.. A method according to claim 15 wherein the tensioning and heating steps during said other portion of the yarns travel are correlated at the tensile stress necessary to extend the yarn to the limit of its stretch characteristics.

:19. A method according to claim 15 wherein the tensioning and heating steps during said other portion of the yarns travel are correlated above the tensile stress necessary to extend the yarn to the limit of its stretch characteristics but below the yield point of the structural elements of the yarn.

20. A method according to claim 15 wherein the tensioning and heating steps during said other portion of the yarns travel are correlated at the yield point of the structural elements of the yarn.

7' 21. A method according to claim 15 wherein the tension ing and heating steps during said other portion of the yarns travel are correlated above the yield point of the structural elements of the yam.

22. A method according to claim 15 wherein the heat applied to the yarn is correlated to the temperature to which the yarn is to be subjected in subsequent fabriciinishing operations.

23. The method of reducing, eliminating or reversing the direction of a torque in a torque stretch yarn which has been twisted in one direction, heat-set at a given temperature under tension and twisted in the opposite direction, which comprises the steps of twisting said yarn in said opposite direction to a selected degree, heating said oppositely twisted yarn at a desired temperature relative to said given temperature under correlated tension, cooling the heated yarn to yarn-set the filaments in the oppositely twisted formation, and twisting said yarn in the one direction to said selected degree, the desired temperature and the-selected degree of twisting being correlated to produce the degree and direction of torsion desired in the y 24. A processed torque stretch yarn characterized by uniform reorientation of the structural elements of the yarn components to thereby exhibit substantial uniformity throughout its length in its latent and manifest physical characteristics of shape, luster, cross-sectional area, texture, dimensional stability, torque, resilience, residual shrinkage, stretch, recovery from stretch, and elasticity, said yarn having substantially balanced torque and moderate bulk and a plurality of individual filaments manifesting a plurality of partially spiralled formations of opposed direction .which remain separate from one another with 1 7 out tending to twist upon themselves or pigtail when relaxed, said formations being yarn-set.

25. A processed torque stretch yarn characterized by uniform reorientation of the structural elements of the yarn components to thereby exhibit substantial uniformity throughout its length in its latent and manifest physical characteristics of shape, luster, cross-sectional area, texture, dimensional stability, torque, resilience, residual shrinkage, stretch, recovery from stretch, and elasticity, said yarn manifesting high stretch and high bulk and a minimum of torque when relaxed and when tensioned and having a plurality of individual filaments manifesting spiralled formations of varying magnitude of opposite directions, and twisted upon themselves or pigtailed, said formations being permanently set in the yarn.

26. A processed torque stretch yarn characterized by uniform reorientation of the structural elements of the yarn components to thereby exhibit substantial uniformity throughout its length in its latent and manifest physical characteristics of shape, luster, cross-sectional area, texture, dimensional stability, torque, resilience, residual shrinkage, stretch, recovery from stretch, and elasticity, said yarn having substantially balanced torque and a high bulk and a plurality of individual filaments manifesting a plurality of partially spiralled formations of opposed direction which remain separate from one another and in frequently tend to twist upon themselves or pigtail when relaxed, said formations being yarn-set.

27. A processed torque stretch yarn characterized by uniform reorientation of the structural elements of the yarn components to thereby exhibit substantial uniformity throughout its length in its latent and manifest physical characteristics of shape, luster, cross-sectional area, texture, dimensional stability, torque, resilience, residual shrink-age, stretch, recovery from stretch, and elasticity, said yarn having substantially balanced torque and high bulk and a plurality of individual filaments manifesting a plurality of partially spiralled formations of opposed direction which remain separate from one another without tending to twist upon themselves or pigtail when relaxed, said formations being yarn-set.

28. A processed torque stretch yarn characterized by uniform reorientation of the structural elements of the yarn components to thereby exhibit substantial uniformity throughout its length in its latent and manifest physical characteristics of shape, luster, cross-sectional area, texture, dimensional stability, torque, resilience, residual shrinkage, stretch, recovery from stretch, and elasticity, said yarn manifesting high bulk and an absence of torque when relaxed and substantial torque when tensioned and having a plurality of individual filaments manifesting spiralled formations of varying magnitude of opposite directions, and twisted upon themselves or pigtailed, said formations being permanently yarn-set in the yarn.

29. A method of reprocessing torque stretch yarns comprising the steps of unwinding said yarn from a supply package, continuously passing said yarn through tensioning apparatus to tension the same, continuously passing said tensioned yarn through a, second tensioning appar-atus operable to apply a different tension to the yarn, continuously heating said yarn while under the control of one of said tensioning apparatus, and continuously winding said processed yarn on a take-up package.

30. A method of processing yarn comprising the steps of unwinding said yarn from a supply package, continu ously processing said yarn to form torque stretch yarn, thereafter continuously passing said yarn through at least one tensioning apparatus, continuously heating said yarn while under the control of said tensioning apparatus, then continuously passing said torque stretch yarn through a second tensioning apparatus, and continuously winding said processed yarn onto a take-up pack-age.

31. A reprocessed torque stretch yarn having in at least a portion of its length a filament have substantially regular opposed partially spiralled formation, the spirals of said filament being less than one convolution.

References Cited in the file of this patent UNITED STATES PATENTS (Corresponding British Patent 787,619, Dec. 1 1, 1957

Claims

1. THE METHOD OF PROCESSING MULTIFILAMENT "TORQUE STRETCH YARN" WHOSE STRETCH CHARACTERISTICS HAVE BEEN SET AT A GIVEN TEMPERATURE COMPRISING THE STEPS OF CONTINUOUSLY ADVANCING THE YARN, CONTROLLING THE DEGREE OF TENSION IN SAID TRAVELLING YARN IN AT LEAST ONE PORTION OF ITS CONTINUOUS TRAVEL, SAID TENSION BEING BELOW THE BREAKING TENSION OF THE STRUCTURAL ELEMENTS OF THE YARN, HEATING SAID YARN DURING SAID PORTION OF ITS CONTINUOUS TRAVEL TO A TEMPERATURE NOT SUBSTANTIALLY GREATER THAN SAID GIVEN TEMPERATURE AND CORRELATING THE CONTROLLED TENSION AND THE HEAT IMPARTED TO SAID YARN WITH THE TENSILE FORCE NECESSARY TO EXTEND THE YARN TO THE LIMIT OF ITS STRETCH CHARACTERISTICS AND THE TENSILE FORCE NECESSARY TO EXTEND THE YARN TO THE YIELD POINT OF THE STRUCTURAL ELEMENTS OF THE YARN TO THEREBY CONTROL THE PHYSICAL CHARACTERISTICS IN THE REPROCESSED YARN.