US3079745A - Fluid twiste apparatus for twisting yarn - Google Patents

Description

March 5, 1963 A. L.. BRI-:EN ETAL 3,079,745

FLUID TWISTER APPARATUS Foa 'rwIsTING YARN Filed Aug. 2s, Asso 4 sheets-sheet 1 $56.55 -G4 $16.55 FIGJG INVENT S ALVIN l.. BRE MARTIN V. SUSSMAN NZM @MLM/1..,

ATTORNEY March 5, 1963 A. L.. BREr-:N ETAL FLUID TWISTER APPARATUS FOR TWISTING YARN Filed Aug. 23, 1960 F I GJ 4 Sheets-S eel'l 2 FIG. 19 Flzo 50 lig* FIG.5I26 1:16.27

F|G.3I FIGJZQ 1:56.30

ALVIN LJBREEN MARTIN V. SUSSMAN ATTORNEY FIG.28

March 5, 1963 A. L.. BREEN ETAL 3,079,745

FLUID TWISTER APPARATUS FOR TWISTING YARN Filed Aug. 25, 1960 4 Sheets-Sheet 3 ZONE IIS

TWIST FIXIIIG I I 'l INVENTORS ALVIN L. BREEN MARTIN V. SUSSMAN ATTORNEY March 5, 1963 A. l.. BREEN ETAL 3,079,745

FLUID TwIsTER APPARATUS FOR TwIsTING YARN Filed Aug. 23, 1960 4 Sheets-Sheet 4 INVENTORS ALVIN l.. BREEN FIG@ MARTIN V. SUSSMAN MW u, n' f BY g: E 6 ATTORNEY United States Patent O 3,079,745 FLUrD TWISTER APARAJTUS FOR TWlSTING ARD Alvin Leonard Breen, Kennett Square, Pa., and Martin `Victor Sussman, Istanbul, Turkey, assignors to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Aug. 23, 1960, Ser. No. 87,516 1 Claim. (Cl. 57-34) (Filed under Rule 47(a) and 35 U.S.C. 115) This invention relates to apparatus for twisting, bulking, or crimping yarns continuously, and to products produced thereby. This application is a continuation-inpart of application S.N. 598,135 filed July 16, 1956, by Alvin L. Breen and Martin V. Sussman, which issued as U.S. Patent No. 3,009,309 on November 2l, 1961.

lt has long been known that a yarn can be crimped by twisting, setting the yarn in the twisted configuration, and then back-twisting the yarn. In a batch process true twist is inserted into the yarn, the yarn is packaged, heatset, and then back-twisted to give the yarn its crimp and bulk. When such a process is carried out continuously, a temporary twist is imparted to the threadline by a falsetwister while simultaneously exposing the yarn to yarnsetting means, eg., heat, steam, solvent, etc. The temporary twist is removed immediately after leaving the twister, and the yarn is taken up on a suitable package. Examples of batchwise processes for imparting twist are disclosed in U.S. Patents 2,019,185, Kagi; 2,019,183, Herberlein; 2,197,896, Miles; and 2,564,245, Billion. Continuous processes and apparatus for false-twisting are disclosed in U.S. Patents 2,089,198, Finlayson et al.; 2,089,199, Finlayson et al.; 2,189,239, Whitehead; 2,111,211, Finl-ayson et al.; 2,463,620, Herberlein; and 2,741,893, Vandamme et al.

Nylon filaments were the iirst thermoplastic textile materials capable of being heat-set and having adequate recovery from deformation so that bulky and stretchtype Helanca yarns could be prepared. The initial process developed to make such yarns was a batch-type operation in which a continuous yarn was highly twisted, a package of the twisted yarn was then heated under suitable conditions, and then the package was backtwisted to give a yarn that, on relaxation, coiled, curled, or crimped sufiiciently to provide great bulk. ln addition to the increased bulk, the yarn bundle had the elastic properties of a conventional spring without the helical regularity thereof.

The most time-consuming step in producing so-called Helauca or stretch-yarns is twisting. Mechanical twisters with rotating mechanical parts have severely limited rotative speed because of friction and the effect of centrifugal force on the rotating parts. The highest attainable speeds are of the orderl of 150,000 r.p.m. and this is for a false-twister which is more than nine times as fast as a standard commercial down-twister. Relative eiliciency of specially designed false-twisting apparatus and continuous twisting process versus la conventional twister batch process is described in Fibres (Natural and Synthetic), vol. 16, August 1955, pj 276. As described therein, a 60-denier nylon yarn which is twisted 65 turns per inch, heat-set, and then back-twisted Via the conventional twister route (12,000 rpm.) can be handled at the rate of 0.4 pound/spindle/week of 168 hours. A false-twister (32,000 rpm.) can produce this same stretch-yarn at the rate of 1.8 pounds/spindle/week (168 hours) or about 4.5 times faster than the batch operation. 011e rea-5011 Why these older processes and false-twisting apparatus have not enjoyed extensive commerci-al success is their relatively slow speeds, low output and eiliciencies,

3,079,745 Patented Mar. 5, 1963 ice lack of product uniformity, and high maintenance costs which rendered the product very expensive.

One object of this invention is to provide an efficient high speed yarn-twisting device containing no mechanical moving parts. Another object of this invention is to provide a yarn-twisting device capable of twisting yarn at a rate of over one million turns per minute. Another object of this invention is to provide an apparatus for twisting yarns at higher speeds and at lower tension than has heretofore been utilized.

According to this invention apparatus is provided for imparting a high speed twisting motion to a filament, yarn, or other strand by torque applied to the strand by means of a high velocity stream of fluid, preferably air, at a velocity of at least 1/2 sonic velocity. For an ladequately uniform product, tens-ion on the strand, upstream of the fluid stream applying said torque, must be less than about 60 grams, preferably less than 15 grams, and suicient to avoid twist-doubling, i.e., second order twist. Accordingly, in its simplest embodiment, the apparatus of this invention comprises, in combination, high velocity fluid twister means and feeding means for passing yarn through the twister at controlled low tension of less than 60 grams. The iluid twister comprises a yarn passageway which is a smooth curved concave surface associated with one or more iluid conduits positioned to direct a stream of fluid circumferentially Iabout the inner periphery of the concave surface. The yarn passageway may be integral with the iluid conduits, or the latter may be spaced apart from the yarn passageway but in position to direct fluid substantially tangentially to the inner periphery of the curved concave surface at some point. The axis of iluid ilow (entering the yarn passageway) must not intersect the axis of the yarn passageway, but it .may lie in a plane substantially perpendicular to the longitudinal axis of the concave surface, or in a plane inclined up to about degrees or more from this perpendicular in order to exert forward movement or braking action upon the yarn in addition to twisting motion. There may be a plurality of conduits directing iluid ow about the periphery of the concave surface, and these conduits may be spaced longitudinally or circumferenti-ally or both about the yarn passageway. Naturally, in order to obtain the highest degree of torque on the yarn, all of the fluid conduits, where there is a plural-ity should be directed in substantially the same tangential direction. lt is not necessary, however, that the longitudinal axes of all the fluid conduits lie in the same or parallel planes with respect to the axis of the yarn passageway. One or more or a plurality of fluid conduits may have axes perpendicular to the axis of the yarn passageway while one or more others may have axes inclined to impart forwarding and twisting motion to the yarn while a lesser number of fluid conduits may have axes inclined backward toward the axis to partially inhibit the passage of the yarn therethrough. ln the case where there are a plurality of fluid conduits supplying fluid to the yarn passageway, it may be desirable to provide one or more exit ports along the yarn passageway, and these may be positioned at any convenient points.

In the drawings, which illustrate specific embodiments of the invention,

FIGURE 1 is an elevation of a simple embodiment of fluid twister, as viewed from a direction at right-anglesto both the yarn passageway and the single iluid conduit, FIGURE 2 is an end view in the axial direction of the yarn passageway of the fluid twister of FlGURE l, FIGURE 3 is an elevation of a more complex fluid twister having a plurality of lluid conduits and intermediate exhaust ports along the yarn passageway,

FiGURE 4 is cross-sectional end view on line 4-4 of FiGURE 3,

FIGURE 5 is a longitudinal cross-section taken along the axis of the yarn passageway (see line 5-5 in FIG- URE 6) of a modified uid twister having a slot-shaped iluid conduit,

FIGURE 6 is an end view of the iluid twister of FIG- URE 5,

FIGURE 7 is a longitudinal cross-section, similar to that of FIGURE 5, of a fluid twister having a slot-shaped fluid conduit and a plurality of exhaust ports,

v FIGURE 8 is an end view of the iiuid twister of FIG- UREv 7,

FIGURE 9 is an end view of a lluid twister similar to that shown in FIGURES l and 2 but modiied by having the uid conduit extended a short distance beyond the intersection with the yarn passageway,

` FIGURE 10 is a cross-section along line liI-Iti of FIGURE 9,

FIGURE l1 is an elevation of a duid twister having a plurality of fluid conduits arranged in pairs entering the yarn passageway from opposite sides, the view being taken in a direction parallel to the axes of the iuid conduits,

FIGURE 27 is an end view of the fluid twister of FIG- URE 26,

FIGURE 28 is an end view similar to FIGURE 14 to further illustrate the motion of yarn in the yarn passage- Way,

FIGURE 29 isv an-end view of a fluid twister similar to that of FIGURE 14 but having a yarn passageway which is somewhat larger in diameter at the point of uidentry than at either yarn passageway port,

FIGURE 30 is a perspective view of an extremely simple construction of fluid twister,

FIGURE 31 is a cross-sectional end view of'a modified form of the uidtwister of FIGURE 30,

' of the apparatus,

'A FIGURE 12 is a cross-sectional end view online 12,-12

of FIGURE 11, Y t FIGURE 13 is a longitudinal cross-section of a uid twister similar to that of FIGURE 1 but having a single cylindrically-shaped fluid conduit at right-angles to the yarn passageway,

FIGURE 14 is an end view of the uid twister of FIGURE 13 which also illustrates the motion of yarn in the yarn passageway during operation,

FIGURE 15 is a longitudinal cross-section of a uid twister having a plurality of iluid conduits extending into the yarn passageway from a manifold,

FIGURE 16 is an end View of the uid twister of FIGURE 15,

FIGURE 17 is a cross-sectional end view of a iiuid twister similar to that of FIGURE 4 but having pairs of opposed uid conduits for alternative use so that the direction of twist is reversed by merely shifting the supply of fluid from one conduit of the pair to the other conduit, FIGURE 18 is a cross-sectional end view of a double vortex fluid twister having a pair of parallel and connected yarn passageways located on each side of a fluid conduit so that shifting yarn from one passageway to the other reverses the applied twist,

FIGURE 19 is a longitudinal cross-section of a uid twister similar to that of FIGURE 13 but having a yarn passageway which decreases in diameter towards the point of entry of the fluid conduit,

FIGURE 2O is an end view of the uid twister of FIGURE 19,

FIGURE 2l is a cross-sectional end view of a iluid twister similar to that of FIGURE 2 but having a venturishaped uid conduit,

FIGURE 22 is a cross-sectional end view of a uid twister similar to that of FIGURES 13 and 14 but having an additional fluid conduit located so as to introduce uid into the yarn passageway at a different point and in an opposing direction for the purpose of varying the rate of twisting of yarn as it passes through,

FIGURE 23 is a cross-sectional end view of a iiuid twister having fluid conduits entering the yarn passageway at four locations around the circumference,

FIGURE 24 is a cross-sectional end view of a uid twister having a pair of fluid conduits entering a noncylindrical yarn passageway from opposite sides,

FIGURE 25 is a cross-sectional end view of a iluid twister having fluid conduits of dierent diameters entering a cylindrical yarn passageway from opposite sides,

FIGURE 26 is an elevation of a uid twister similar to that'of FIGURE 5 but the slot-shaped fluid conduit is into the yarn passageway,

FIGURE 34 is a plan view of a further embodimentV ofthe apparatus,

FIGURE 35 is a plan view of still another embodimentY of the apparatus,

FIGURE 36 is a plan view of an additional embodiment of the apparatus, and

FIGURES 37 to 41 illustrate various novel yarn products which can be produced with the apparatus of this invention.

FIGURES l through 31 illustrate the manner of interception of a yarn passageway 51 by one or more iiuidl passageway is numbered 51 irrespective of whether the yarn passageway is cylindrical in form or a slot or a venturi or the like. Similarly, the uid conduit is numbered 52 in each of the figures and so on.

The uid twister of FIGURE 1 contains an axial yarn` passageway 51 which, in this embodiment, is substantially cylindrical in form throughout its length. A conduit for tluid 52 intercepts the yarn passageway at 53 at an angle of about 60 degrees to the axis thereof and is positioned so that the longitudinal axis of the uid conduit 52 does not intersect the longitudinal axis of yarn passageway 51,'

as shown in FIGURE 2. When gas under pressure is passed through uid conduit 52 so that it reaches at least 1/2 sonic velocity upon emerging into the yarn passageway,

51, suicient torque upon any yarn in the yarn passageway is created to produce a high rate of twisting if the yarn is maintained at a tension less than about 60 grams. At relatively high uid velocities less dense uids may be employed to obtain substantially the same torque produced by a higher density uid traveling at lower velocity. Fluid may be supplied to the fluid conduit 52 by any con- Venient means. As shown by FIGURES 1 and 2, fluid may be supplied by tting 54, which is fastened over the fluid conduit exterior port and threaded for attachment to a fluid supply pipe. Preferably, the yarn passageway will have rounded edges at both ends to minimize tearing of the yarn bundle, and in accordance with one embodiment shown in FIGURES 3 and 4, the yarn passageway is widened by bevels 55 at the yarn entrance and exit ports.

similar in shape.

When the yarn passageway is of substantial length, itVV 1s desirable that the yarn passageway contain one or more uid exhaust ports 56, as illustratedv in FIGURES 4 and 8, in order to facilitate removal of uid from the Forexample, in each of the FIGURES 1 through 3l the yarn- Naturally, it is not necessary that these widened portions of the yarn passageway be symmetrical or evenv yarn passageway. The fluid twister may be designed to provide for ease in Stringing-up a threadline by providing a string-up slot running the entire length of the yarn passageway. The string-up slot may simultaneously serve as an air conduit or exhaust port, as desired. FIG- URE 3 illustrates one possible form of string-up slot S7.

FIGURES 9 and l0 illustrate a preferred embodiment for providing froid entry into the yarn passageway whereby the duid will vbe cushioned against itself at the point of entry into the yarn passageway and thereby malte a very smooth operation possible. rihis result is obtained, as shown in FGURES 9 and l0, by designing the lluid twister so that the fluid conduit extends beyond the yarn passageway to form a fluid conduit extension 58.

In the case of twisters containing a multiplicity of fluid conduits, it is convenient to design the twister in a manner to provide a manifold region 61 (FIGURE 15) to facilitate maintenance of air at constant pressure to all fluid conduits where that is desired. Fi-GURE 16 illustrates a particular embodiment of fluid twister containing a string-up slot 57. The twister of FIGURE 16 is divided in two sections, as shown, to further facilitate string-up, the two sections being held together by bolt d3. lf desired, the sections may be hinged at d2. In FIGURES 23 and 25 there is provided a manifold housing 54 suitable for surrounding the entire twister head with fluid, and the twister head in these embodiments is porous to permit the transmission of fluid therethrough at a slow rate to reduce yarn-to-wall friction, FIGURE 27 illustrates a twister in which the lluid conduit 52 has a shoulder 65, and FIGURE 29 illustrates a twister in which the yarn passageway is somewhat wider at the point of fluid entry than at either yarn passageway port.

The fluid twisters of FGURES 17, 18 and 22 are useful for applying intermittently opposed twisting to produce alternating twist yarn. Reversal of twist is accomplished with the duid twisters of FIGURES 17 and 22 by supplying iluid alternatively to the opposed fluid conduits with suitable rotary valve means or the like interposed between the uid source and the twister proper. The direction of the twisting vortex applied to yarn can also be reversed in a different way without interrupting the flow of fluid when using the fluid twister shown in FIGURE 18. This has two cylindrical yarn passageways 51a and Sib which have parallel axes spaced apart at a distance somewhat less than their diameters so that the passageways are interconnecting along their lengths, hence have a gure-of-eight cross-section as shown in FIGURE 6. The interconnection is of suicient size to permit the yarn to be shifted from one passageway to the other by changing the point of yarn feed, as with conventional traverse means. Fluid is supplied to both passageways simultaneously through the common huid conduit 52, located so that the axis is in the plane equidistant from the axes of the passageways, to form vortices which twist in opposite directions as indicated in the drawing.

The yarn passageway of the fluid twister of this invention preferably has an internal diameter (in the case where the yarn passageway is cylindrical) of between about 0.002 inch and about 0.125 inch and preferably between 0.015 and 0.040 inch. Yarn passageways which are not cylindrical will preferably have cross-sectional areas at the initial point of contact between the yarn and stream of uid corresponding to areas of circles having these diameters. The ratio of yarn hole diameter to the yarn diameter should be in the range of 2l0 and preferabiy 3 6. For liuid twisters of this invention having yarn passageways with cross-sectional areas comparable to a circle having a diameter up to about 0.125 inch, the direction of rotation of the yarn bundle during twisting is in the direction of lluid flow about the inner periphery of the yarn passageway, and this direction of rotation will be referred to herein as direct twisting. With yarn passageways having cross-sectional areas comparable to a circle with a diameter of more than about 0.125 inch,

6. centrifugal thrust forces the yarn bundle to roll on the inner periphery of the yarn passageway in a motion analogous to that of a planetary gear. This twisting action is referred to herein as reverse twisting, and it will be apparent that with reverse twisting the twist imparted to the yarn is opposite to the twist obtained by direct twisting, even though in each instance the direction of fluid flow about the yarn passageway is the same.

It is an important feature of this invention that during the twisting of the yarn bundle, whether the twisting action is direct twisting or reverse twisting, the longitudinal axis of the yarn describes a surface similar to the inner surface of the yarn passageway and spaced from the inner surface of the yarn passageway by a distance equal to about the radius of the yarn bundle. This feature of the instaat invention is illustrated in FIGURES 14 and 28. FIGURE 14 illustrates direct twisting of a yarn bundle 59 in yarn passageway S1 and shows, by arrows, that the yarn twists about its axis in the same direction as fluid flow about the inner periphery of the yarn passageway while the axis of the yarn bundle describes a surface spaced from the inner surface of the yarn passageway by a distance at least the radius of the yarn bundle, both surfaces having a common longitudinal axis. FIGURE 28 illustrates the motion of a yarn bundle 59 subjected to reverse twist action showing that the yarn bundle rotates about its axis in a direction opposite to the flow of fluid about the inner periphery of the yarn passageway while the axis of the yarn bundle moving in the same direction as the ow of duid about the passageway describes a surface spaced from the inner surface of the yarn passageway by a distance equal to the radius of the yarn bundle, both of said surfaces having a common longitudinal axis.

Some prior attempts to rotate yarn by means of fluid flow have been characterized by endeavors to rotate the yarn about its own stationary axis by the turbine action of a fluid vortex. Yarn tensions have been maintained suliiciently high so that the yarn was maintained rigid, thereby preventing displacement of the yarn from the center of the yarn passageway despite eccentric uid forces acting on the yarn periphery. Low torque was imparted to the yarn because of the short lever arm through which the tangential forces must act due to the small diameter of the yarn.

In another species of uid twister such as disclosed in U.S. Patent 2,515,299 to Foster et al., yarn is passed at substantially no tension through an enlarged chamber filled with revolving air and the yarn balloons within the chamber to provide an annular reach which is revolved in the manner of a mechanical twister. Because of the enlarged chamber, excessively low tension on the threadline and the distortion of the threadline, throughput rate is low. Consequently, as disclosed in this patent, such a false-twister is suitable for low rates of twist of heavy threadline (e.g., staple roving).

When operating with the apparatus of the present invention, however, ballooning of the yarn, to the extent that it occurs, is greatest outside the uid twister and the yarn undergoes a twisting action as above described at tensions below 60 grams. Balloonng of the s'rand within the twister is not discernible. High twist is thus obtained, and yarns 'having more than 50 turns per inch are readily obtained at twisting rates substantially hgher than on million turns per minute when the path of yarn rotation is contined within a yarn passageway of small diameter, that is, less than about 0.06 inch, or in larger diameter passageways where reverse twist occurs by the yarn rolling on the inside of the passageway wall. For direct twisting, the rate of yarn twisting is about equal to the rate at which the yarn bundle rotates around the axis of the yarn passageway. For reverse twisting, the rate of twisting may exceed this rotation rate since the yarn may roll about its own axis many times in making one turn about the axis of the yarn passageway. Fluid twisters of this invention having a yarn passageway diameter of about 0.125 inch may be operated with Yrelated to cost of manufacturing.

direct twisting or reverse twisting by adjusting yarn tension, alignment of the yarn passageway, feed rate of yarn supply, or the like. The term yarn as used herein is representative of any strand material in the form of a monolament, multililament or spun staple yarn or film strips.

The cross-sectional area of the yarn passageway in the fluid jet device of this invention is preferably about equal to that of the uid inlet conduit at the point of interception. Fluid jet devices in which the ratio of the cross-sectional area of the yarn passageway to the cross- Sectional area of the uid inlet Orifice at the point of interception varying from about 4:1 to about 1:10 may be used, however. Preferably, the yarn passageway and the uid passageway are cylindrical in shape but either or both may be other than circular in cross section and neither need be uniform in area or cross-sectional form throughout its length. The figures illustrate various fluid jet devices of this invention, but it will be apparent that the figures are illustrative only, and many variatfons of the uid twisters shown in the gures will be readily apparent. j The length of the yarn passageway may be widely varied. A very eicient fluid jet device is one having a yarn passageway length between about 0.125 and about 0.5 inch and having only one luid inlet port. The length of the yarn passageway should not be less than its diameter (or its substantial equivalent where the passageway is not circular in cross section). Preferably, the yarn passageway will be about l times its diameter and desirably will not be more than 25 times its diameter. Longer yarn passageways may be utilized and are very elicient when reverse twisting action is employed. In the case of fluid jet devices having relatively long yarn passageways, it is often desirable to utilize a plurality of fluid supply conduits and one or more exhaust ports connected to the atmosphere or to a reduced pressure source to facilitate escape of the driving uid and minimize back pressures. With short yarn passageways, exhausting of Huid is no problem since the fluid passes directly through the open ends of the yarn passageways. ItV may be desirable to have some fluid supply conduits angled forward to impart forward motion to the yarn while others exert rotative thrust. Obviously, this effect can also be achieved with a fluid twister having a longer yarn passageway and a plurality of fluid inlet ports.

Pneumatic twisters with yarn tubes of very small diameter show surprisingly high efficiency in terms of air consumption vs. useful work produced. This is an important consideration since air consumption is directly Fluid yarn twisters of thisl invention appear to operate at highest eliiciencies when the yarn tube is about the same as the individual air inlet tubes. In a preferred embodiment, the air inlet tube axis is olf-center with respect to the yarn tube axis by approximately the dimension of the air tube radius, and the yarn tube length is between about two and about fifteen times the yarn tube diameter in order that motivating air may exhaust freely. With this arrangement, exhaust air is skewed with respect to the yarn tube axis, thereby tending to promote instability of processing particularly when tension on the yarn is very low. Careful adjustment of the yarn axis positions entering and leaving the fluid twister to coincide with the axis of air exhaust flow provides substantially much more stable and uniform operation and with fluid twisters, which are capable of such high rates of twisting as compared t0 mechanical twisting devices, stability of operation and uniformity of product are to be preferred over optimum efficiency.

Air at room temperature is preferred for twisting yarn in the fluid jet device of this invention but the air may be heated or' refrigerated, if desired. Steam or solvogenicga'ses may Valso be used provided that the plasticizingaction, if any, is'not harmful.- For certain twisting applications it may be desirable to utilize a fluid with a plasticizing effect. Other gases, such as carbon di- Oxide, nitrogen, and the like, may be utilized, if desirable. In order to operate the process in accordance with the invention, it is necessary that the fluid, when a gas, be at a velocity of 1/2 sonic velocity or more immeditely prior to impinging upon the yarn, to effect the high twisting rates of this invention. Non-gaseous uids should reach velocities suicient to do comparable twisting. Such fluids, of course, do not have to reach the same velocities because of their higher densities.` By increasing the velocity of the fluid ow on the yarn, twisting speeds in excess 'of this amount are obtained.

For the production of uniform stretch yarns, it is important that the tension on the yarn being twisted (measured adjacent to and up-stream of twister) be maintained within critical tension range at which high twist without twist-doubling occurs. Where a high degree of twist is desired at a high throughput rate, preferred tension limits are between about 3 grams and 15 grams. Tension on the yarn downstream of the twister may be somewhat different (higher or lower) than that on the yarn upstream of the twister. For certain very high yarn speeds, Le., G-2000 y.p.m. and up and forheavier deniers, i.e.-, 10U-500 denier or larger, it is possibleto use very low tensions. The lowest operable tension if a uniform product is desired is a tension just great enough to prevent twist-doubling, that is, second or third order twist. Operating at such very low tensions results in a non-steady state condition and can be useful for novelty or intermittent etfects but not for the production of a uniform stretch yarn.

FIGURE 32 shows in schematic form one possible string-up assembly in which the pneumatic twister of this invention may be utilized. FIGURE 32 shows yarn being taken from a yarn package 75 passed through pigtail 76 to tension feeding means 77, such as the tension Vgate shown, which is utilized to maintain yarn tension in the twisting zone at less than 15 grams. From the tension gate the yarn is passed through a heating zone 78, where the yarn is heated by a hot plate, and then through tbe yarn passageway of twister 79, then between advancing rolls 80 and S1 through pigtail 82 and wound up as backwindable package 83. Tension between the nip rolls and windup package S3 is maintained at standard windup ten sion.

In one method of operation of FIGURE 32 apparatus, zero twist poly(ethylene terephthalate) continuous filament yarn is passed through the tension feeding means at yards per minute; windup speed is 128 yards per minute and yarn tension is 3 grams measured upstream of the hot plate. Process twist is Z. The fluid twisterV is of the type shown in FIGURES 15 and 16 and operates on 30 pounds per square inch air. The hot plate is maintained at 270. The liuid twister is slightly misaligned with respect to the direction of travel of the threadline with the result the yarn threadline alternately sticks and slips at the yarn passageway ports so that the yarn is twisted and cranked in a pulsating manner. The pulses permit Z twisted sections of the yarn to pass through the twister without twist removal, with the result that S twisted sections appear in the yarn between the Z twist sections that had escaped the twister action. The resulting yarn is called an alternating twist yarn. It has the appearance of a highly twisted crepe yarn, and is very twist lively and very cohesive. The net twist in the yarn is essentially zero, that is, there are as many'turns of S twist as there are Z twist. The yarn product is illustrated in FGURE 40 and the process in Table I, Example 54.

An alternating twist yarn is made Via a process similar to the above except that instead of misaligning the jet the tension gate is vibrated at a rate of about 2O times per second. This causes a corresponding variation in'yarn tension and produces an alternating twist product.

- Alternating twist Continous filament yarn may be made using the iiuid twister IGURE 22. in this case, the air supply is alternated between opposing air inlets. This gives a positive alternating twist action and a product in which the S and Z portions of twist are very similar to each other in length and structure.

The high speed yarn-twisting apparatus of HGURE 32 may be utilized very effectively and efficiently to produce so-called Helanca or stretch-type yarn at exceedingly high rates of production when feed rolls are used as the tension feeding means 77 instead of a tension gate. The feed rolls may be as shown at 142 of FlGURE 36. in

this apparatus, a textile denier yarn of less than about 2,000 denier is taken from supply package 75, passed through pigtail 76 through feed rolls 77, and plasticized by passing over a hot plate in zone 7S before entering fluid twister 79 and take-up rolls S13, 31. Tension upstream of the twister is maintained below l grams by regulating the relative speeds of the feed and take-up rolls. A tension gate may be used in place of feed rolls 77 but is much less desirable because of the non-uniform product produced and increased difficulties in control. Upon entering the fluid twister, the yarn is continuously subjected to a high rate of false-twisting. This twist extends backward along the yarn to the feed roll 77 The yarn in this twisted state, upon passing over the hot plate, is plasticized in the twisted condition. The heat plasticized twisted yarn, upon leaving the presence of the hot plate and coming into contact with exhaust fluid leaving the yarn entrance port of the fluid twister, is quenched (deplasticized) prior to entering the uid twister. ln order that the fluid twister provide this quenching eifect on the heated twisted yarn, it is important that the temperature of the exhaust uids from the fluid twister be maintained at a temperature 50 C. below the plasticized yarn temperature, preferably 100 C. below and ideally 150 C. or more below the heat plasticized yarn temperature. Due to the falsetwisting action of the fluid twister, the deplasticized twisted yarn, immediately upon passing the point of greatest torque in the liuid twister, is back-twisted to substantially its original state of twist, thereby produc-ing a stretchtype yarn which is passed through nip rolls and Si, over pin S2, and taken up as a back-windable package -33 preparatory to use.

ln place of using a hot plate at zone 73, any suitable heating means, such as a hot pin, infra-red light, steam tube or cell, hot water, and the like, may be employed. Pl-asticizing the yarn may also be achieved in the absence of heat as, for example, with solutions of chemical plasticizing agents or similar materials. Steam or other plasticizing material used to treat the yarn can be applied by use of a torque, or texturing jet similar to those described herein and also in US. Patent 2,783,609.

vl/nen plasticizing is effected with heat, the temperature of the heating medium must be regulated so that the average yarn temperature does not reach the melting point of the yarn material. The heating medium temperature or source of hea-t may be above the melting point of the yarn and the surface of the yarn may be above its melting point so lon as yarn speeds are such that average yarn temperature (over a cross-sectional area of yarn) is maintained below the yarn melting point. rlemperatures lower than the second-order transition temperature o-f the yarn material are usually not employed because, under these conditions, any crimping of the filaments is not permanent and utility of the product is reduced. The preferred temperature is that which results in plasticization without fusing or degradation.

At high yarn speeds high temperatures and/ or longer exposure distances are necessary to provide temperatures at the desired plastcizing level. These higher yarn temperatures may be achieved by means of an auxiliary heating device or pre- .ea-ter in the threadline, but a simple means for achieving this same effect is to have the yarn pass twice over a single heated plate so that yarn is preheated at it passes up along one face of the hot plate to l0' a snubbing point and then is plasticized as the yarn progresses down across the reverse face of the hot plate to a fluid twister.

To produce highest quality stretch-yarns with the apparatus of this invention, that is, to achieve maximum bulking or crimping, it is essential that the tension on the yarn adjacent to and upstream of the twister be maintained below about 15 grams. Tension may be controlled by a tension gate or other suitable means but these are diicult to control and produce non-uniform products. Preferably, tension is controlled directly by regulating the relative speeds of the feed rolls and windup rolls. The yarn speed differential between feed and wiudup rolls will be governed by the degree of bulking desi-red as well as the relative operating speed of the process, that is, throughput of yarn in yards per minute. Yarn speed differential between input and output with respect to the uid twister may vary between about 5% to about 50%, and yarn speed through the iiuid twister may vary from 50 to about 1,000 yards per minute or higher. For economical operation, yarn speed will ordinarily be at least about yards per minute and preferably at least about 400 yards per minute. Because yarn tension is controlled directly by the speeds of the feed and windup rolls, tension upstream of the twister is easily maintained constant below 15 grams while tension downstream of the twister is also maintained conetant.

It is essential, in operating the apparatus of this invention to produce a useful bulked yarn or stretch-type yarn, that back-twister yarn leaving the uid twister be taken up on a package suitable for baokwinding. Substantial yarn tension must be employed downstream of the windup rolls during the windup, and preferably the yarn tension at windup is in accordance with standard windup practices in the art. Windup yarn tensions will ordinarily be substantially greater than the upstream twisting tensions utilized and should be suflioient to produce a good back-windable package of yarn.

Air velocity in the iluid twister must be maintained constant and within critical limits if a uniform stretch yarn is desired. A minimum air velocity of at least 1/2 sonic velocity is essential, and it is also extremely important that the air velocity in the fluid twister (immediately prior to impinging upon the yarn as mentioned above) not exceed that which causes the yarn to undergo twist doubling (e.g., second-order twist) in which the twisted yarn twists upon itself.

The apparatus of this invention is useful for treating any natural or synthetic lilamentary material, particularly filaments of polyamides, polyesters, and polymers of acrylonitrile. Suitable polymers can be found among the fiber-forming polyamides and polyesters which are described in US. Patents 2,071,250; 2,071,253; 2,130,- 523; 2,130,948; 2,190,770; and 2,465,319. The preferred group of polyamides comprises such polymers as poly(hexamethylene adiparnide), poly(hexa.methylene sebacamide), poly(epsilon caproamide), and the copolymers thereof. Among the polyesters that may be mentioned, besides poly(ethylene terephthalate), are the corresponding copolymers containing sebacic acid, adipic acid, isophthalic acid as well as the polyesters containing recurring units derived from glycols with more than 'two carbons in the chain, eg., diethylene glycol, butylene glycol, decamethylene glycol and trans-bis-lA-(hydroxymethyl)cyclohexane. Non-thermoplastic materials, such as the natural bers-wool, silk, cotton, the synthetic protein iibers, regenerated cellulose and the likecan also be highly crimped or bullied although they are not as elastic as the thermoplastic fibers. Both types of materials can be made into elastic fabrics having improved bulk, covering power (opacity) and hand. The apparatus is useful for treating both staple and continuous filament yarns of all types having deniers less than about 2,000 and preferably less .than about 800, and is useful for staple yarns since it permits false-twisting of staple yarns and back-twisting of single staple yarns through the zero-twist point-feats not heretofore possible.

'Ihe apparatus of this invention is preferably used to treat continuous filament yarn immediately after the process of cold-drawing. An economic procedure involves incorporating a fluid twister alon-g a threadline immediately after cold-drawing and prior to standard tension yarn takeup as described subsequently in connection with FIGURE 33. It is obvious, however, that the apparatus can be used in a separate operation, either prior to or after drawing or after some indeterminate storage period.

Since retraction of stretch-yarns in the presence of steam is a measure of wet recovery properties and varies directly with the degree of stretchiness, the quality of stretch-yarns can be graded on the basis of percent retraction, using the following formula-tion:

(skein length after steaming) X 100 To'ldetermine percent retraction of a skein of yarn, the skein is wound at substantially zero tension on a reel with a periphery of 112 cm. to give a total denier of 1400. It is then suspended in front of a suitable scale and loaded with a weight of 1.82 grams to give 0.0013 g.p.d. A static eliminator is passed along the yarn bundle to prevent ballooning of the filaments, if necessary. Atmospheric pressure steam is directed on the suspended yarn bundle for about five seconds. High quality continuous filament nylon stretch ya-rns ordinarily have retraction values calculated in accordance with the above equation ofthe order of 85% to 560%. Such a shrinkage range is achieved with thermoplastic continuous filament yarns. Lower retraction values o-f such yarns are useful if increased bulk with some stretchiness is adequate for the end use at hand. Such lower values will also result if the yarns being treated are no-t thermoplastic and/or are made from staple fibers.

In the production of uniform stretch-yarn, it is undesirable to package a twisted portion of yarn which has resisted the jet untwisting action. These so-called hard spots can be produced by fluctuations in tension or twisting action of the jet, twist snubbin-g variations and/ or differences in the degree of yarn setting. Excessive Itemperature in the setting zone and heavy non-uniform finish deposits also tend to produce hard spots in the yarn by fusing the surface filaments together so that they tend to resist url-twisting to a much greater extent than unfused filaments. By twist snubbing is meant snubbing a twisted yarn in a manner to prevent the twist from passing the snubbing point.

Y Constant downstream twist snubbing is desirable to produce uniform stretch or bulk yarn. Torsional slippage of an irregular character at the downstream snubhing point allows some sections of yarn to escape the jet untwisting action to some extent, producing variable bulkiness or in severe cases hard spots previously mentioned.

'Y A suitable yarn finish to control static, friction, and yarn running properties is desirable. The finish may also serve to improve heat transfer among the filaments increasing the rate and/or the degree o-f setting. For a uniform product it is desirable that the nish be applied uniformly.

" FIGURE 33 illustrates a preferred string-up assembly whereby a uid twister of this invention may be utilized Vto impartrtwist to a yarn bundle immediately after drawing the yarn and prior to packaging the drawn yarn. In accordancewith this embodiment,v undrawn yarn is taken from a package 9&3, passed over pin 91, through nip rolls 92, and then turned about draw pin 93 before passing around the larger circumference of a step-down roll 94 which draws the yarn. Conventional canted separator rolls 95 are used in conjunction with lthe stepdown roll. The yarn is then passed through plasticizing zone (preferably heated) 96 prior to entering fluid twister 97. Tension on the yarn upstream of the twister is main-tained below l5 grams by means of step-down roll 94. Yarn coming from the fluid twister 97 is passed around the smaller circumference of the step-down roll 94, whereas yarn feeding the fluid twister must first pass around the larger circumference of the step-down roll. Thus, the yarn feeding to the uid twister is traveling at a greater speed than the yarn leaving the uid twister by an amount predetermined by the diameters of the larger and smaller sections of the step-down .roll 94. After leaving the step-down roll, the yarn is passed through pigtail 98 and wound up a-s backwindable package 99 at standard tension. In FIGURE 33, as just described, the yarn is plasticized and twisted prior to changing direction at guide 100. Alternatively, the plasticizer and twister may be placed after guide 100 as shown in dotted lines so that the yarn has a longer path of travel between step-down roll 94 and the plasticizing zone. This arrangement of heater and twister on the down leg of the yarn permits insertion of supplementary heaters along the yarn path between the large section of roll 94 and guide 100.

At 100 in FIGURE 33 there is shown a species of upstream twist snubbing guide. A snubbing guide in the process for producing stretch-yarn should ideally provide a positive grip on the threadline to prevent twist leakage upstream of this point. The usual pinch rolls provide this action very effectively. Such rolls are not convenient, however, in the usual draw-twisting operation because they tend to make yarn wraps difficult to remove. Pairs of rolls, such as rolls and 116 of FIGURE 34, mounted cantilever fashion with a small angle between their axes for wrap separation are preferred. Several wraps are generally necessary to provide su-icient friction for yarn speed and tension control. This type of system is less effective as a twist snubbing device since the twist is reduced gradually in its passage upstream of the first contact point rather than abruptly as in the case of the pinch roll. The twist snubbing in this case also-applies a force to the threadline tending to displace it along the roll axis, and in a direction depending on the direction of twist. In effect, the yarn tends to roll or walk across the face of the contacting surface under the inuence of the twisting force. This interferes with proper wrap separation and tends to introduce non-uniformities by fluctuations in yarn-to-roll friction which cause the snubbing action to vary. An auxiliary step on the stepdown roll will control this walking The last wrap of yarn about the feed roll prior to the yarns entering the heater is taken about this step, and the twist direction is arranged so that the torque causes the yarn to move toward the face above the step. This face prevents the displacement of the last wrap which snubs the twist sufficiently to eliminate the problem of Wrap separation in the remaining wraps.

Loosely meshing gears may be used as the guide 100 to provide twist snubbing. This arrangement has the advantage that it can apply the twist snubbing action to a number of threadlines simultaneously regardless of twist direction. For simplicity, it is preferred that these gears are driven by the yarn itself although any suitable auxiliary driving arrangement may be employed. A simple pulley or belt driven by the yarn feed roll provides a reliable drive and is particularly useful for very light- Weight yarns. Another simple means is to impinge an air jet on the gears to drive them. Exhaust air from the fluid jets can be used for this purpose. Other arrangements may be used to grip the moving threadline either processing zone.

smeg-i i3 intermittently or continuously so as to snub the twist at a substantially fixed point. Those systems which impose little tension change on the moving threadline and cause a minimum of tension fluctuations are preferred for the purposes of this invention.

It is important that `the yarn in the zone between the iiuid vortex and the upstream snubbing point should have minimum frictional Contact with plasticizing devices such as hot plates, and the like. vIn any practical process, this requires careful alignment of the jet, the hot plate slot, and the upstream snubbing guides.

In a specific illustration of the operation of the stringup of FIGURE 33, undrawn poly(heXamethylene adipamide) yarn is taken directly from the spin bobbin, passed over a feed roll with a surface speed of 133 yards per minute, over a draw pin, and around a draw roll, with a surface speed of 440 yards per minute. The yarn is drawn 3.3 times due to the difference in speed between the feed roll and the draw roll. The yarn makes three turns around a separator roll and the draw roll and then passes over a twist-snubbing guide, over a hot plate, through a pneumatic twister, and back to a small diameter roll which is mounted concentrically and on a common shaft with the draw roll. This latter small roll has a surface speed which is less than the draw roll. The yarn passes twice around this smaller roll and its separator roll. This smaller roll and separator roll can be considered as a windup roll. The difference in -diameter or surface speed of the small and large concentric rolls determines the overfeed to the pneumatic twisting' process and hence determines the tension in the From the windup roll, the yarn travels to a standard pirn windup. The product produced is a 70-34 stretch nylon.

The yarn path between the draw roll and the Windup roll can be considered as the stretch processing7 zone. The hot plate 96 and twister 97 can be mounted as shown in FIGURE 33 in which case the processing is designated as .-up processing. Alternatively, the twister and hot plate can be mounted as shown by the dotted outline in FIGURE 33 in which case the twisting process is designated as down processing. For high speed operation, the down processing procedure is preferred since an additional hot plate can be mounted on the up traveling leg of the processing zone which will supplement the heating effect of the hot plate immediately upstream of the pneumatic twister.

A variation of the above operation is particularly useful as applied to monofilament yarns of the type used in ladies hosiery. Where monofilament yarns of round cross section are used, the smooth cylindrical surface does not offer as much purchase for the fluid vortex and, therefore, twisting is less efficient than with multifllament yarns, although acceptable products can be produced. Multilament yarns with as few as two filaments per yarn bundle are twisted more effectively, but it is desirable to have as few filaments as possible in hosiery yarn to achieve maximum shearness and freedom from snagging. A process which appears to provide optimum results in View of these considerations applies the treatment on the apparatus of FIGURE 33 to a temporarily composite yarn composed of two or more filaments with separate final packaging provided for each lament in the yarn bundle. This requires that the filaments are separated at a point beyond the fluid vortex. Pins or guides located downstream of the iiuid twister can be used to accomplish this separation. The resultant monofilarnent yarns have a corkscrew-like configuration which provides additional stretchiness, bulk, and desirable texture to the product. Similar results may be obtained by applying the process to monoiiiaments of non-round cross section. ln this case the stretch developed in the iinal knit garment stems largely from the yarn twist liveliness and resulting stitch distortion.

FIGURE 34 illustrates one procedure for utilizing the "si L iiuid twister of this invention to twist a yarn bundle coming directly from a spinneret and prior to being drawn. Filaments 11S issue from spinneret 111 and converge in guide 11.2. Upon leaving the guide, the filaments are divided into two groups and pass upon opposite sides of pin 113. The filaments are twisted immediately upon leaving pin 11.3 by means of iiuid twister 114 farther downstream, the twist imparted by liuid twister 114i backing up to pin 113. No heating Zone is necessary with the string-up of FIGURE 34 since the filaments are in a plasticized state upon passing pin 113. Twist imparted to the yarn bundle upon leaving pin 113 is fixed in the yarn either by cooling, evaporation, or otherwise, prior to entering iiuid twister 114 from whence it is passed around rollers 115 and 116 and then to backwindable package 118 which is driven by drive roll 117.

in addition to improving crimping and elastic propertes of stable and continuous filament yarns, the apparatus of this invention can be used for treating a single continous filament or staple roving and plyed roving or spun yarn or, in fact, any lamentary strand material. While the twist applied to a running threadline is false, the twist applied to projected endsof staple fibers is a true twist and the whipping and twisting of these ends about the yarn bundle produce a very coherent product. When treating staple roving, a yarn can be spun at speeds much higher than those obtainable on a conventional spinning frame; and by varying the processing elements, the

product can be Varied all the way from the conventional spun yarn to a highly bulked stretch-type yarn.

As other variations of the treatment, two or more different yarns, continuous filament or staple, may be processed simultaneously at the same or different rates feed speed and at the same or different tension levels with constant or pulsating feed rates, to give yarns of varying characteristics and/or novelty. One such yarn product is analogous to the so-called thick-and-thin yarns with lengths containing high twist (crimped) connected by lengths substantially untreated or unchanged (uncrimped) and/ or an alternating twist yarn. Particularly interesting combinations can be prepared wherein the two different materials (eg, nylon and rayon) have dissimilar retraction chararteristics. The differential retraction characteristics can be enhanced by using two different feed rates or tension levels, thereby increasing the ultimate bulking that will be achieved when the yarns or fabrics are given their final process retraction. Finishing techniques, ie., shrinking, agitation or the like can improve or modify the bulking characteristics particularly when two dissimilar yarns are used.

While the yarns made with the apparatus of this invention are particularly useful in stretch-type knit fabrics, they also provide useful effects in other fabric forms such as tricot and woven goods. Woven fabrics, particularly those made from yarns of non-round cross sections, show desirable improvements in bulk and texture. High luster or glitter frequently associated with yarns of non-round cross sections is generally reduced by the subject twist-setting process. Examination of such yarns under suitable magnification shows that the filaments are randomly rearranged with respect to one another so as to break up the reliecting planes which tend to produce glitter. Accompanying this effect is a random twist configuration along the individual filaments giving a lengthwise texture not normally associated with simple cross section modifications.

Desirable crepe-like fabrics may also be made of yarns of this invention. in this case the crepe figure may be developed in fabric finishing by agitated relaxation treatments such as tumble scour provided the fabric construction is sufficiently open to alloy yarn distortion under the influence of their twist liveliness. In woven crepe fabric the crimp amplitude tends to be limited by the relatively tight fabric construction as compared with knit fabrics. Por this reason, it may be desirable to modify the yarn stretch characteristics for stretch-yarns intended for weav- FIGURE 35 illustrates a uid twister apparatus of this invention which may be utilized to produce a wide variety of novel specialty yarns. In the schematic drawing of FIGURE 35, roving is unwound from package 125 in conventional manner and passed in sequence through a trumpet guide 125, drafting rolls 127, and over applicator roll 128 which is revolving in a bath of adhesive solution. The roving is then plasticized in heater 130 and twisted by tiuid twister 131 and subsequently wound on package 133 which is driven by drive roll 132. It is not essential that adhesive be applied to the roving during the processing, and it is also not necessary that the roving be plasticized prior to twisting. Either or both of the adhesive application and plasticizing may be omitted or may be utilized, depending upon the particular product desired.

In the case where no adhesive is applied to the roving and plasticizing is also omitted, the product produced by the twisting action of the uid twister is a sheaf-yarn, such as illustrated in FIGURE 39. The product is called a vsheaf-yarn because it resembles sheaves of wheat or, more exactly here, sheaves of staple yarn attached end to end and tied at random intervals along its length by staple lfibers twisted firmly about the circumference thereof. In-

termediate the Vtightly bound portions of the yarn the staple fibers are substantially parallel to one another.

, In utilizing the apparatus of FIGURE 35 and processing staple roving as above described but applying an adhesive ksolution to the roving prior to twisting but omitting any plasticizing of the roving prior to twisting, there is obtained an alternate twist staple yarn having an appearance similar to the twisted yarn shown in FIGURE 40 with the exception that FIGURE 40 is directed to an alternate twist "continuous filament yarn. An alternate twist staple iiber yarn has essentially the same coniiguration but with a somewhat more fuzzy appearance due to the multiplicity of Iiber ends protruding from the iiber bundle. When the apparatus of FIGURE 35 is operated with a plasticizer, for example, a heat plasticizer, but without application of adhesive, a parn product with somewhat greater bulk but `somewhat less stability Vthan the yarn product is obtained with adhesive application. When adhesive application alone is utilized in the absence of any plasticizing means, it is essential that the adhesive be suiciently volatile so that it will be set (by polymerization or solvent volatilization) during the interval between application of the adhesive solution and entrance into the fluid twister. The air discharge from the iiuid twister accelerates the setting of solvent based adhesives.

Operation of the apparatus of FIGURE 35 is illustrated by passing poly(hexamethylene adipamide) staple lament yarn, issuing from the drafting rolls of a commercial spinning frame, through an air twister and then to a windup roll with a surface speed of 23 y.p.m. The yarn path from the drafting rolls, through the twister to a guide, located just prior to the windup, is a straight line. Yarn tension above the twister is 2 grams. Supply air ,pressure to the twister is 30 p.s.i.g.

A continuous staple yarn is formed by the above process, which yarn is held together by random filament ends which are wrapped tightly about the yarn axis. The yarn is illustrated in FIGURE 39. The process conditions are shown :in Example 50 of Table I.

Viscose rayon staple filament yarn issuing from the drafting rolls 127 of a commercial spinning frame at 50 y.p.m. is treated in the apparatus of FIGURE 35 whereby the yarn is passed over an applicator roll 128 and a `heated plate 130 prior to entering the pneumatic twister. "The applicator rolls apply a size (polyvinyl alcohol emulsion) to the twister yarn. The hot plate (280 C.) dries `the size and ixes the yarn in its twisted configuration. jDue to the combination of size and heat, the twist is fixed -so tightly that some of the twist passes through the twister unaltered, with the result thatvopposite hand twist appears -yarn is combined with viscose rayon stable fiber (1.5 d.p.f., 21/2) using the equipment of FIGURE 35. Operating conditions are shown in Example 53 of Table I. The yarn is passed through the forward drafting rolls along with the drafted Viscose rayon staple iiber yarn. The filament yarn and staple yarn are immediately integrated by the twist imparted by the fluid twister. The twisted filament-staple yarn then is treated with polyvinyl alcohol by the applicator roll and heated to 250 C. to set the yarn, then passed through the twister to windup. VIn another example, adhesive is applied to both yarns prior to passage through the drafting rolls to produce a coated yarn having substantially greater bulk than in' the case of yarn treated with adhesiveafter twisting.

By a variation of the apparatus of FIGURE 35 indicated by the dotted lines in the drawing, it is a simple procedure to add one or more additional yarn structures to the roving prior to twisting. For example, a yarn package 134 containing either continuous or staple {ilaments may be passed over pin 135 and joined with the roving as it passes through nip rolls 136. As in the case with the processing of roving alone as illustra-ted in FIG- URE 35, the joint processing of the multiplicity of filamentary structures may be accompanied by the application of an adhesive solution by applicator roller 128 and/ or plasticizing thereof by heat or other means at plasticizer station 130. Alternatively, an adhesive solution may be applied to the continuous or staple iilament prior to its joining with the roving or application of adhesive to the roving or to the combination of roving and staple or continuous yarn may be omitted, as desired, to produce a wide variety of novel yarn structures. v

FIGURE 36 illustrates an apparatus for producing other novel yarns using a fluid twister of this invention. In using this apparatus, a continuous or staple filament yarn is unwound from package 140, passed over pinA 141, through nip rollers 142, and subjected to the rotary twisting action by fluid twister 143. The rotary action upon the yarn is shown by dotted lines 150. In the specic illustration shown, short lengths of a second iilamentary material 144 are dropped from reservoir 145 upon the carrier yarn as it is rotated and twisted with the result that the short lengths of iilamentary material are wound tightly about the rotating (carrier) yarn and become lirmly bound thereto to form slubs. Alternatively, the slubs may be dropped on the carrier yarn downstream' of the uid twister but this procedure is less desirable -because slubs are even more firmly bound to the carrying yarn as the yarn carrying the slubs passes through iluid twister 143. The slub yarn product is then passed through nip rollers 147 and wound on package roll 148 which vis driven by drive roll 149. In operating in accordance with this embodiment, the carrying yarn may be either staple or continuous ilament yarn, and the secondary yarn, which is added to form slubs, may likewise be either staple or Y continuous iilament yarn.

Using the apparatus shown in FIGURE 36, polyage, passed through the feed rolls, through a Huid twister operating on 40 pounds per square inch air to a windup roll, and iinally to a backwindable package. Windup speed is y.p.m. Tension in the threadline is maintained at 10 grams. i

Immediately upstream of the twister, pieces of staple yarn (1.5 denier per filament, 3 inch viscose rayon staple) are fed to the rotating, twisting threadline from a hopper. On contacting the rotating, twisting threadline, the staple fibers are immediately entrained into the threadline by the rapid rotating motion, and form randomly spaced slubs along the threadline. An enlarged illustration of the slubbed yarn is shown in FIGURE 37. The slub yarn is novel in that the slub is held Vto the carrier yarn with two directions of twist. One end of the slub is twisted in the S direction, the other end is' twisted in the Z direction. The process conditions shown in Example 57 of Table I produced the product illustrated in FIGURE 37.

Another type of slub yarn (crepe tail slub yarn), illustrated in FIGURE 4l, is made by running a yarn through the FIGURE 36 apparatus at a tension of only 3 grams. The high twist imparted to the cold yarn at this low tension causes the yarn to 4form branched slubs which pass through the twister. The stability of the branched slubs can be improved by size applied before the twister. These branched slubs can also be produced by plucking the threadline so as to create short rapid tension changes.

A slub yarn comprising slubs of continuous filament on a continuous filament carrier yarn is prepared by substituting a continuous filament package for the reservoir 145 in FIGURE 36. Running at a speed of 50 y.p.rn. and using a uid twister of the type shown in FIGURES 13 and 14 which is operated at 30 pounds per square inch air pressure, continuous filament yarn to be used for slubbing is allowed to contact the rotating carrier yarn threadline. The slubbing yarn is immediately wrapped about the carrier yarn and forms slubs which consist of short sections of carrier yarn about which numerous layers of the slubbing yarn are wrapped. The tension on the carrier yarn is maintained constant at between 10 and 25 grams, whereas the tension on the slubbing yarn is varied in a rapid and random fashion betweenand 25 grams. Wrapping occurs when the tension in the slubbing yarn drops below the tension in the carrier yarn. Layered slubs occur when the tension in the slubbing yarn approaches zero grams. The wrapping and carrying functions of each yarn may be reversed by reversing the relative tension levels. Process conditions are shown in Example 56 of Table I. The slub yarn product illustrated in FIGURE 38 is unique in that the slub consists of yarn wrapped about the carrier yarn in the direction of twist that exists upstream of the twister, whereas the unslubbed, but plyed sections of the yarn are twisted in the twist direction that exists downstream of the twister.

The fluid twister is particularly adapted to making of slub yarns, since the twister yarn passage offers' little resistance to the passage of a slub, whereas mechanical twisters snub the yarn over pins, wheels, etc., which would offer vsubstantial resistance to the passage of siubs, with the result that the threadline would be subject to frequent breakdowns.

Using a nozzle of the type shown in FIGURES l and 2 whose air port diameter is one-quarter of an inch and whose yarn passageway diameter is one-half an inch, it ispossible to spin a real twisted staple ber. For example, poly(hexamethylene adipamide) staple liber (2 inches long, 11/2 denier per filament) is dropped into the air supply to the nozzle ofA FIGURE 1. A length of yarn is inserted in the yarn passageway and withdrawn at a rate of 20 yards per minute. The direction of withdrawal is opposite to the direction of the air port entry to the yarn passageway. The air supply pressure is 60 pounds per square inch. The air stream carrying its entrained staple fibers causes a rapidly rotating vortex in the yarn passageway and rotates the length of yarn initially placed in the yarn passageway at high speed. The rotating yarn wraps thevstaple bers, carried by the air stream, about itself, and as the yarn is withdrawn from the yarn passage (in the direction previously ndicated), a continuous staple yarn with real twist is formed and is continuously withdrawn from the twister. This yarn is wound on a suitable package and resembles conventional spun staple of a 5/1 cc. Specialty yarns such as slub yarns and covered yarns may be prepared in such an arrangement by running a threadline through the twister while adding staple fibers to the air stream.

As illustrative of one method of operating the apparatus of this invention, poly(hexamethylene adipamide) yarn of a type suitable for tire cord consisting of 240 filaments of approximately 6 denier per filament giving a total yarn denier of 1680 is processed in the general arrangement shown in FIGURE 32. In this case, because of the relatively poor heat transfer through the heavy yarn bundle, it is necessary to use several heating zones interspersed with booster iiuid twisters which apply additional torque tothe threadline to overcome air drag and other forms of friction tending to reduce the twist level in the twist heating zone. .In the example at hand, three conventional slot type heaters are used in sequence. Between the first and second and second and third heaters (in the direction of threadline movement), booster fluid twisters are used supplied with high pressure steam which gives additional plasticizing action. 'The third heater is made several times the length of the other heaters to remove moisture in `order to ensure complete deplasticizing. The zone betweenA the last heater and the linal pneumatic twister is also longer than the other similar zones. A transverse flow of air is used in this region to assist threadline cooling. The product collected at the windup in this case shows lament curliness in which the radius of curvature is somewhat larger than that observed with the textile denier yarns but suiiicient to be attractive in certain forms of upholstery and carpet yarn uses.

In the examples following, which illustrate operation of the apparatus of this invention, tension on the yarn upstream of the iiuid twister is controlled lby feeding means to provide a low tension above that at which twistdoubling occurs. Air velocity in the iluid twisted is at least 1/2 sonic.

The examples shown in Table I illustrate the operation ofthe fluid-twisting devices of this invention and the products which may be produced thereby. Table I indicates for each example the yarn utilized, the conditions under which it was processed, the fluid twister utilized, the type of string-up assembly employed, and the nature of the product produced along with its stretch characteristics in terms of percent steam retraction where these data are pertinent. Air velocity in all examples where air is used as a uid is at least 1/2 sonic velocity. The deplasticizing (quenching) Vmedium in all examples is air except that in Example 20 the deplasticizing medium is water, and in Example 29 steam is utilized for quenching. The temperature ofthe quenching medium is room temperature (26l C.) in all cases except Example 29 where steam at C. is utilized for quenching. The fluid-twisting medium in all examples is air, except that in Example 29 the fluid medium is steam. In Examples 8 through 14 air consumption amounts to 0.7 cubic foot per minute. In all examples illustrating production of stretch-yarn, the yarn is twisted at least 50 turns per inch, and in many instances, over 60 turns per inch.

The examples of Table Il illustrate preparation of low denier stretch yarn of poly(hexamethylene adipamide) suitable for ladies hose. Products of Examples 5S, 59, and 6l are prepared using the coupled drawing-twisting apparatus shown in FIGURE 33, and those of Examples 60', 62, 63, and 64 are prepared using the dual thread processing apparatus of FIGURE 35. All yarns are continuous filament yarns freshly drawn prior to twisting and having an initial twist of about 0.1 turn per inch. Upstream tension on the yarn is about 2 grams. The heatsetting is accomplished by passing the yarn at speeds ranging from 425 to 780 yards per minute through a slot V16 T S vinch x 1A inch'x 10 inches heated at 225 C. Air pressure is 95 psig. and twisting action is direct. The twister has an air passage diameter of 0.025 inch and a yarn passage diameter of 0.025 inch,

TABLE I Example 1 2 3 4 5 Yarn material Polyhxamethylene ad ipa- Same as 1 Same as 1 Same as 1 Same as 1.

mi e Denier 70 70 70 200 70. Number filaments 34 34 34 12 34. Source Shipping package Same as 1 Same as 1 Same as 1 Same as 1. Type of yarn Continuous Continuous Continuous Continuous Continuous. Initial tWist l/ Z 2 Z 7 Z l/ Feed speed (ypm.) 's` 158 645 11 1 451. Windup speed (y.p.m.) 85 12R 597 95 400. Tension (gms). 2 4 1-2 2 2. Process twist- S S 7 7. Z Fluid twister Figs. and 16 Figs. 15 and 16;. Fig. 31 Fig. 31 Figs. 9 and 10. Heat-setting temp., C 250 270 325 260 l 325. Type heater. Hot slot, Me X 13" Same as 1 Hot slot| Mo" X 25--. Same as 1 Same as 2. Air pressure (psig.) 60 65 65 90. TWiStIlg Film1 Direcf Direct Reverse Rever e Direct. Turns per minute 215,000 340,000 1,200,000 240,000 900,000. Percent steam retraction 12R 100 100 100 93. Product characterization Stretch yarn Stretch yarn- Stretch yarn Stretch yarn Stretch yarn- Air passage drain. (mhes)-- 5 holes at .031 5 holes et .031 12 holes et .063 12 holes et .063 1 hole at .025. Yarn passage diam. (inches) .0 .06 .31 .3

Example 6 7 s 9 10 11 Yarn material.-. Same as 1 Same as 1 Same as 1 Same as 1 Same as 1 Same as 1. Denier 40 70 70 70 70 7 Number filaments 13 34 34 34 34 34.

Source Same as 1 Same as 1 Same as 1 Same as 1 Same as 1------. Same as 1. Type of yarn.. Continuous Continuous Continuous.. Continuous Continuous Continuous. Initial twist 12 Z le 7 Z l Z A l/ Z.

Feed speed (y.p.m.) Tension gate 115 Tension gate. Tension gate Tension gate. 341.

Windup speed (y.p.m.) 10o-50o 10o 40o 45o nfl 309.

Tension (gms.) 5 0.1-- 1.5-. 1.5--- 1.2-. 1.5.

Process tjwist Z S S S S S.

Fluid twister Fig. 31 Figs. 13 and 14- Figs. 9 and 10... Figs. 9 and 10.. Figs. 9 and 10-.. Figs. 9 and 10. Heat-setting temp., C 240 260 325 325 525 325,

Type heater Hot plate, 30 Same as 1 Same as 1-.-.--. Same as 1 Same as 1. Same aS 1. .Air pressure (psig.) 40 100 100 100 100.

Twisting action Reverse Direct Direct Direct Direct Direct.

Turns per minute l 950,000". 1,080,000 1,150,000 800,000. Percent steam retraction 100 124 7 53 l 144.

Product characterization Stretch yarn Stretch yarn Stretch yarn Stretch yarn Stretch yarn Stretch yarn. Air passage drain. (in ches) 12 holes at .063... 1 hole at .094 .02 .02 .02 .025.

Yarn passage diam. (inchei .31 .188-. .025 .025-. .025. .025.

Example 12 13 14 15 16 17 Yarn material Same as 1 Same as 1 Same as 1 Same as 1 Same as 1...---- Same as 1. Denier.- 70 70 70 A0 20.

Number filaments- 34 34 Source Same. as l Same as 1 Same as 1. Type of yarn Contlnuous Continuou Continuous. Initial twist Z 2 M Z.

Feed speed (320.111.)- 330 Tension gatc Tension gate. Windup speed (y.p.m.) 10Q 7n 141.

Tension (gms.) 2.5 1 1.

Process tzwisf S I Z s s.

Twisting actgfm Direct Direct Direct Reverse Direct.

Turns per mlmltenu.- 770.000 630,000-400,000

Percent steam retraction 144 50-35 00 274. Product characterizatlon Stretch yann-.- Stretch yarn- Stretch yam- Stretch yarn stretch yarn Stretch yam Air passage diam. (inches). .0 .02 .0 1 hole at .031 12 holes at .063.. 5 holes at .031. Yam passage diam. (inches) .025. .025.- .025.. .0

Emmnle 18 19 20 21 Yarn material Same as 1 Same as 1 Same as 1 Same as 1. Denier- 14 l5 70 70 Number filaments 2 1 34 34 Source Same as 1 Same as 1 Seme as 1 same as 1 Type of yarn Continuous Continuous Continuous Continuous. Initial tW1 st Zorn Zero 1/ 7. 1/2 Z Feed speed (y.p.m.) 117 11 s 1110 225,

Windup speed (y.p.m.) 10o 14a 200 Tension (girls.) l 1 q 6 ui vwis er igs. 9 and 1 Fi s. 9 and 10. Fi 31- Heatsetting temp., C- 23s 240g 252g Figs 9 and 10' Type heater Same as 6 Same as 1 Same as 6 Air pressure (p.s.i.g.) 40 40 s .100

Twisting action- Direct Direct Reverse Dimm;`

Turns per minute- :Igercentt stelam itracttsionqt h hlm 93 ro uc c arac riz a -ion c yrete amont yam--. Stretch monclament yarn.. Stretch lament am..- Crim ed am Air passage dlarln. (inches). 1 hole at .063 1 hole at .OC3 12 holes at .os3 1 hoiepat ,525, Yarn passage diam. (inches) .0 .0 ,3 `02 i Example 22 23 24 25 Yarn material Polymexamethylene adip- Same as 22.- Poly(ethylene-terephthalate) Same as 24.

amide) undrawn.

Denier 252 (undrawn).. 70 ...Y 70.

Number filaments 34 34 34.

Source. Spin boboin Same as 22 Same as 22.

Type of yarn Continuous Y Continuous -Y Continuous.

Initial twist Zero Zero Y Zero Zero.

Feed speed (y.p.m.). 103 (draw roll speed). 98 (feed roll speed)-- 117- 114.

Windup speed (y.p.m. 77 (Windup roll speed 350 (Windup roll spee 10 100.

Tension (gms.) 1 6 Y Y Y 4 4 Process twist Z Z S. Fluid twister Figs. 11 and 12.-- Figs. 15 and 16 Y Figs. 9 and 10.. Figs. 9 and 10. Heat-setting temp., C- 240 Y 230 Y 240 Y Y Y 240.y Type heater Same as 1 Radiant tube.- Same as 1--- Same as l. Air pressure (psig.) 19 48 Y 40 Y Y 40. Twisting action- Direct Direct Direct Direct. Turns per minute 220,000.. 240,000. Percent steam retraction-- 116 115 Y YY Y 115V. Product characterization 70-30 stretch yarn Bulked yarn Stretch filament yarn--- Stretch filament yarn; Air passage diam. (inches) 10 holes at .031 5 holes at .031 .Y. 1 hole at .063 1 hole 'at .063. Yarn passage diam. (inches) .0 .063.. Y ;Y. Y Y Y 3. 'Remark Simultaneous twisting and drawing.

Example 26 27 28 29 30 31 Yarn material Same as 24 Same as 24....-- Same as 24 Same as 24...... Poly(epsilon capro- Fortisan regenarn` e). erated cellulose). Denier 70 40 40 70 Y Y -Y Y 70 Y 9 Number laments. 34 27 27Y 34 Y Y Y Y 34 120. Source Supply package- Same as 26 Same as 26 Same as 26.-..-- Same as 26 Same as 26. Type of yarn Continuous. Continuous.-." Continuons.-. Continuous. Continuous .Y.-. Continuous. Initial twist Zero Zero Zero Zero Y Y 3 Z. Feed speed (y.p.m.) 150 114 12o use us 106. Windup speed (52pm.) 128 1m im 110 100 100. Tension (gms.) 3.5-- 1.3-- 1.5-. 'iY Y l-2 1-2. Process twist S 7 Y Z S S. Fluid twister-- Figs. 11 and l2.- Figs. 9 and l0-.. Figs. 9 audio-.. Fig. 27..;...Y. Fig. 27 Fig. 27 Heat-setting te 266 270 Y 265 266v Y 240 200. Type heater. Same as l. Air pressure 80 Twisting actio Direct Turns per minute 240,000 240,000. Percent steam retraction 87--. 106 154 95 Y v Y Y Product characterization Stretch yarn Stretch yorin-.. Stretch yarn- "tretch yarn---- Stretch yan1'. Air passage diam. (inches) 10 holes at .031.. 1 hole at .063 1 hole at .063 1 holeYat 063-..- 1 hole at .063. Yarn passage diam. (inches) .063-- .063- .0 .0 .063.

Fvamnle 32 33 34 35 36 Yarn material Polyacrylonitri1e Polyethylene Vinyon N Raw silk Viscose rayon. Denier- 100 Y 66- Y Y 130- Y 150.

Source Same as 26 Same as 26 Same as 26 Same as 26.. Type of yarn Continuous Y Continuous Continuous Continuous. Initial twist-. 0.3 Z. Z Y Y Feed speed (y.p.m.). 116 110 44.

Windup speed (y.p.m.) 100 100 42.

Tension (gms. l-2 1-2 2.

Process twist- S Y S S.

Fluid twister- Fig. 27- Fig. 27- Figs. 1l and 12. Heut-setting temp., c C 220 n Type heater Air pressure (p.s.i.g.).

Same as 1.-- 4o 16 Samevas 1- 4o 180. Hot tube )6" x 13". 30

Twisting action Y YY Y Y Y Y Direct.

Turns per minute 240,000 240,000.Y- 240,000 .Y 240,000 110,000.

Percent steam retraction Y Y Y Y Y Y Product characterization Stretch yarn Bulked yarn-.Y.-- Bulked yarn-. Crirnped yarnm.. Stretch yarn.

Air passage diam. (inches) 1 hole at .063. 1 hole at .063 Y1 hole at .063 1 hole at .063- 10 holes at .031.

Yarn i diam. (inches) .063-- .063- .063- .0

Example' 37 38 39 40 41 Yarn material Cellulose acetate.. Cellulose triacetate.. (l) Fiberglass- Same as 37.

Denier 100 202 s4 11n 100.

Number l'iments Y 32 Y Y 80 Y YY Y Y 40. 15 32.

Source Same as 26 Same as 26. Y Y Same as 26.- Same as 26. Same as 26.

Type oi yarn. Continuous. Continuons- Continuous. Continuous Continuous.

Initial twist- Zero Zero M Z Zero.

Feed speed (y.p.m.). 24 43 52 105 24.

Wlndup speed (y.p.m.) 22.5. 42Y 22.5. 100 22.5.

Tension (gms.) l-2 4 1.3. l-2 1.2.

Process twist.. Z 7v 7 S.:

Fluid twister- Fig. 27- Fig. 27 Fig. 27. Fig. 27 F1gs.5 and 6.

Heat-setting temp., C 200 Y 95 Y 200 ann 200.

Type heater Same as 36 Same as 36... Same as 36 Same as 35.

Air pressure (p.s.i.g.) 40 16 24 40Y 15..

Twisting action Direct Direct Direct D11-pct Direct.

Turns per minute.-- Y Y Y Y 940,000

Product characterization Bulked yarn Stretch yarn Stretch yarn,-.. Crimped yarn... Stretch yam.

Aix' passage diam. (inches) 1 hole at .063 l hole at .063 l hole at .063-- 1 hole at. .063----- l hole at .063.

Yarn passage diam. (inches) .0 .063.. .063 .063 .063.

Remarks. Yarn -wet with 20+ acetone in water. .belote entering heater.

TABLE I (continued) Example Yarn material Denier Same as 24 Same as 24 Same as 24 Same es 24. 1.5 d f.

Number lamenfq 2/6 Source Type of yarn Initial twist Same as 26 taple 40/2 c.c

Same as 26- O/l 0.o. staple yarn..-

Same as 26 ame as 43 Il Same as 26. ame as 43.

Feed speed (y.p.m.) Windup speed (y.p.m.) Tension (gms.) Process twist Tens 74 7 ion gate Fluid twister Z Fig. 27-

Heat-setting temp., C

Z Figs. 11 and 12 170 S Eggs. 11 and 12 Z. Figs. 11 and 12. 26.

Type heater Air pressure (p.s.i.g.)

Same as 42;

9 Same as 42 20 'lwisting action.

Direct Direct Direct Direct.

Turns per minute 150 00 Product characterization Stret Air passage diam. (inches).-.- Yarn passage diam. (inches).. .063- Remarks with reduced fuzz. l Vhole at .063

0 ch staple yarn Same as 42.

Same as 42 10 holes et .031

Reduced fuzz staple yarn.

10 holes at .031.

10 holes at .031.. .053 Y Example point.

Process twist opposite to initial yarn twist. Yarn is twisted through 'zero Yarn material- Denier (last-in Number Hlamenfe Type oi yam Initial twist- Simile Sffmlp Simile Feed speed (y.p.m.) Windup speed (y.p.m.) Tension (gms).

Process twist- Fluid twister Heat-setting temp., C Type heater S Fig. 27 isn S Fig. 27

S Fig. 27

S Fig. 27

Air pressure (psig.) Twisting aotinn Turns per minute Product characterization Air passage diam. (inches)- Yarn passage diam. (inches) Remax-ke 240,000 Crimped yam 240,000 Crimped yarn--.

240,000 Crimped yarn-..

240,000 Crimped yarn.-. 1 hole at .063

Same es 1. 1.5.

Bobbin. Staple roving.

Figs. 11 and 12.

None.

Sheai yarn. l0 holes at .031.

lohole at 063---- 1 hole at .063-

.063. Drafted staple bers led to a fluid y .lJxalnple twister are converted into a continuous yarn, see Fig. 35.

Yarn material Denier Sameas 1 7n Same 3S 1---- 7n Same as 1. 70-34 filament.

Source Type of yarn Initial twist 34 Same as 26 Co171tinuous l 1.50, 2%" staple. Same as 26. Filament and staple.

Feed speed (y.p.m.) Windup speed (y.p.1n.) Tension (gms.) Process twist Fluid twister. Heat-setting temp., C Type heater- Tension gate 40 e; S Fig. :u

Air pressure (p.s.i.g.) Twisting action Figs. 13 and 14. 250

Same as 6. 30.

Product characterization Air Passage diam. (inches) Yarn Passage diam. (inches) Remarks into the threadline.

Semi staple yarn lioles at .063

Note: Cutting edge placed upstream of twister breaks filaments which are then wrapped Bulked yarn 2----- 1 hole at .063-

Staple covered yarn.

1 h le at .094

.188. Staple and continuous filament yarn combined using the setup shown in Fig. 35.

Yarn material Denier- Number lamenfs Source Type of yarn Initial twist. Feed speed (y.p.m.) Windup speed (y.p.m.) Tension (gms.) Process twist Same 8S 24. 70

34 Same as 26 Continuous- Fluid twister Heat-setting te Type heater.

Z Figs. 15 and 16 270 Same as 1 Air pressure (p. Twistjng notion Product characterization-- Air Passage diam. (inches) Direct v5 holes at .031

Crepe1ike cohesive yarn Yarn Passage diam he Remarks...

Y.047 Jet misaligned with respect to operates in e pulsating manner.

yarn travel direction,

Viscose rayon. 1.5

Bobbin. Staple.

Figs. l5 and 16. 280.

Same as 6.

Direct. Alternating twist staple yarn. 10 holes at .031.

.053. Size applied to threedline, while in twisted condition upstream of heater.

TABLE I (continued) Example 56 57 Carrier Slub Carrier Slub Yarn material Same as 1.... Same as T Same as l Viscose. Denier 70 40. 1.5. 3". Ivo. filaments..- 34 Source Seine as 2H Pim.. Bobbin. Type of Vav'n Continuous Cnntiimn Staple. Initial twist- Z M Z Feed speed (y.p.m.) Tension gate. Windup speed (y.p.m.) 50 160. TensionV (Buis.) l-25--.....Y- 0-25-- 20 Proc-ess twist. S i S. Fluid twister Figs. 13 and l4 Figs. 15 and 16. Heat-setting temp. DC l l Type heater None None. Air pressure (p.s.i.g.) 40.

Wisting action Direct Direct. Product characteri ation Slub yarn Slub yarn. Air passage diam. (inches) 1 hole at 040 Yarn passage diam. (inches) .063.. C Remarks Tension on -13 yam varied randomly. Slub Staple fibers are brought into contact with twisting continuous produced at low tension (approx. 0). filaments in Fig. VI. Product shown in Fig. VII.

l Poly(ethylene pipcrizing N,Ndicarboxylate).

2 A fluid jet for expanding yarn as described in application Serial No. 443,313 by A. L. Breen was placed downstream of the duid twister to produce e special bulked yarn.

TABLE II Example 58 59 60 61 Denier. is i s 15 15. Number ilament 1 2 2 4. Type of false twist Unidirect. S or ZN.. Unidirect. both l. S or Z. Balanced one nl. S and l l. Z-- Unidirect. all fil. Sor Z. Feed speed, y.p.m 425-780 425-780 425-780 425. Windup speed, y.p m 399-731 399-731 899-731 399. Process twi t S or 7 S and Z S or Z. Percent steam retraction- 135-450 2-12 157-390. Product characterization. Stretch bi-fil Stretch bi-i Stretch multi-iii.

Example 62 63 64 Denier 15 30 40. Number filamenre 4 10 14. Type oifalse twist Balanced 2 lil. S and 2 fil. Z Balanced 5 nl. S and 5 l. Z Balanced 7 il. S and 7 l. Z. Feed speed, y.p.ru. 425-780 425 425. Windup speed, y.p m 399-731 399 1 399.1 Process twist-- S and Z S and Z S and Z. Percent steam retraction 15G-380 9'-24i 7-165. Product characterization Stretch multi-fil Stretch multi-lil Stretch mu1ti-l.

l Not measured.

Example 65 The yarn products produced by twisting yarn in a duid A heated fluid can be used in the ud twister of this twister in accordance to this invention are structurally invention with either continuous filament or staple yarn. unique qnd novel besldes being charactenzed by Superior Thus, there is obtained a combined plasticizing and heatumflolmltyla C Ompare tonr .atgams Preredt wh setting action while in the overtwistcd condition. Using Die? amca Wlslers n e WIS e yam pr. uc s a simple torque jet as shown in FIGURES 1 and 2 a dividualiilaments and groups of lamerits are twisted even 7 l I single ply, 18 cotton count, l5 Z twist spun yarn cornpart from any bu'ndl twist that may be present' Thls posed of 3 inch, 2.5 denier Polyexamehylene adipa intra-filament twisting is thought to provide the yarn prodrnide) ibers is false-twisted to about 30 turns per inch. CS 'Pallculafly 'he SIeCh-Ya11S, Wlth that lm llsal um* Air is supplied at 90 p.s.i. to give a flow at near sonic 55 fOl'mIY and COheSlVeIleSS Whlch these Yams manifestvelocity of 0.5 ft.3 of cfree air per ininute. 'Ihe nozzle Example 67 was heated to 24U-2:0 C. to plasticize and crimp-set the yarn while in the false-twisted condition. Many of the The Procedure of Example 2 1S Camefi out. 5mg a con' free ber ends were wrapped around the yarn bundle to m1110115 lamellf QOINhEXaI'ncthi/lene adipamide) yarn but give a slieaf-yarn with improved pill resistance as well as the fate 0f WISUHS iS Vafled by Varying the eIlSlOIl 0n bulk. the yarn Vas it passes through the iluid twister. They prod- Example 66 uct is an alternate-twist stretch-yarn having in combina- Example was repeated using Superheated Steam ,at tion the characteristics and properties of both alternate- 200 C. and 50 psi. in place of the air and heating of wlst Yams and Stretch'yams' the nozzle. The yarn was a single ply, 40 cotton count, 65 Example 68 l5 S twist spun yarn composed of 11/2 inch, 2 denier Th d fE 1 1. d t poly(ethylene terephthalate) ber. Yarn speed was 200 e proce ure o Kamp e 1S came. Ou.usmg a con' yards per minute and yarn tension was adjusted so that tmuous mamenf: Olyhexalnethylene adlpamldelylm but the processing was carried out at constant length At the rate of twisting 1s Varied by alternately twisting the this ltension level most of the iluid energy was utilized in 70 yam m the and Z dlrectlons usmg the uld 'twlster of wrapping the free ber ends around the yarn bundle to FIGURE 22 m the apparatus of FIGURE 32 There are give a Sheaf yam This yam when Woven into fabric had 60 twist reversals per minute and a tension compensating much improved pill resistance, as compared to starting device is used to take up tension during the twist reveryarn. The hand of the fabric had a pronounced crisp- Sals. The product is an alternate-twist stretch-yarn having ness as well. both the characteristics `and properties -of both alternate- ,be made without departing from the spirit and scope therep of, it is to be understood that the invention is not limited by the specific illustrations except to the extent defined in the following claim.

We claim:

In yarn ltreating apparatus including means for twisting yarn and means for passing yarn through the twisting 10 means under low tension, the fluid twister for twisting yarn which comprises -a yarn passageway tube having a,V

diameter of 0.002 to 0,125 inch and a length of 2 to 15 times the diameter, a plurality of uid conduits through the tube wall intercepting the passageway with the conduit axes oset with respect to the axis of the passageway and in opposed relationship to each other, each of said conduits having a diameter of about 1/2 to 2 times the diameter of said passageway at the point of interception, and means for introducing uid alternately into said conduits to be directed about the inner periphery of the yarn passageway in alternate directions.

Cooper Feb. 14, 1911 Foster et al. July 18, 1950

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