US3762148A

US3762148A - Texturing process and apparatus therefor

Info

Publication number: US3762148A
Application number: US00238087A
Authority: US
Inventors: H Thrower
Original assignee: Hoechst Fibers Inc
Current assignee: Hoechst Fibers Inc
Priority date: 1972-03-27
Filing date: 1972-03-27
Publication date: 1973-10-02
Anticipated expiration: 1990-10-02

Abstract

A process and apparatus are disclosed for texturing a multistrand textile material. Sufficient electrical charge density is imparted to the strands to cause the strands to repel each other and flare. While the material is in the flared state, it is moved under a predetermined tension through a twist zone where an electrical field is traveling in a closed path transverse to the direction of strand movement. Under the effects of the electrical field, the strands are driven around the closed path of the field and a false twist is imparted to the material. A heating and cooling zone are presented upstream of the twist zone to set twist in the yarn for the production of a stretch yarn. Optionally, a second heat zone may be positioned downstream of the twist zone to produce a low torque, bulk yarn. An electrodynamically rotating alternating current electric field is a preferred means for imparting twist in the twist zone.

Description

Thrower, Jr.

Oct. 2, 1973 1 1 TEXTURING PROCESS AND APPARATUS Primary ExaminerDona1d E. Watkins THEREFOR AttrneyWe11ingt0n M. Manning, Jr.

[75 lnventor: Herbert T. Thrower, Jr.,

Spartanburg, SC. [57] ABSTRACT [73 I Assignee: Hoechst Fibers Incorporated A process and apparatus are d1sc1osed for texturmg a I mu1t1strand text11e matenal. Suffie1entelectr1ca1 charge Spartanburg, SC. denslty 1s lmparted to the strands to cause the strands 1 1 ,Flledi 1972 to repel each other and flare. While the material is in [21] APP] 238,087 the flared state, it is moved under a predetermined tens1on through a tw1st zone where an electrlcal f1e1d is traveling in a closed path transverse to the direction of 1 1 Cl 57/34 R, 57/34 HS, strand movement. Under the effects of the electrical 57/351 57/156, 57/157 1 57/157 Ms field, the strands are driven around the closed path of 1 1 '1- 2 1/04 D011 7/92 the field and a false twist is imparted to the material. A [58] Field of Search 57/1, 34 R, 34 HS, heating and coming zone are presented upstream fth 57/35, 77-34745 156, 157 157 MS; twist zone to set twist in the yarn for the production of 28/1 75 a stretch yarn, Optionally, a second heat zone may be positioned downstream of the twist zone to produce a 1 1 References Clted 10w torque, bulk yarn. An c1ectrodynamica11y rotating UNITED STATES PATENTS alternating current electric field is a preferred means 3,657,871 4/1972 Uchiyama ct 111. 28/1 R for imparting twist in the twist Zone- 3,537.249 11/1970 Mayer 1. 57/5811) 1411,2114 11/1969 Corbaz ct =11. 57/5891 34 6 D'awmg F'gures 3,107,478 10/1963 Arshinov et a1. 57/773 X n-1 In-fl w I 1 1, WH /5e lll 11 51 1 lll111 11 :JLILI 1/ Ll/LlL S c 71 LAT J' 54 i I 53 55 4 5 44 O F l {/V L .1

TEXTURING PROCESS AND APPARATUS THEREFOR BACKGROUND OF THE INVENTION During the past twenty years, an enormous amount of technology has evolved in the area of texturizing synthetic fibers to produce either stretch or bulk yarns for the production of knit goods, especially garments. These yarns in general are multifilament, thermoplastic yarns and are generally knitted into hosiery, innerwear, outerwear and the like for the apparel markets.

Numerous processes have been developed for treatment of the yarns to impart the desired stretch or bulk qualities thereto. These processes are of several distinct types, each of which is accompanied by numerous improvements thereto. For example, a large effort has been expended in the false twist processing of multifilament synthetic fibers where the fibers are passed around a pin located in or adjacent a rotating spindle. In this fashion, a false twist, which is a term well known to those skilled in the art and need not be further discussed, is imparted to the yarn being processed. Numerous improvements have further been made to improve the rotational speed of the false twist spindles, the placement of the pin with respect to the spindle, and the like so as to improve the quality of the yarn being processed and to improve the speed at which the false twist is imparted. False twist has also been imparted to fibers by frictional engagement between the filaments and a moving or rotating body, such as twist bushings, oppositely driven belts, and the like. Both stretch and bulk yarns can be produced by the false twist processes.

Other processes for the texturizing of synthetic yarns include the gear crimp process where the yarn is passed between meshing gears and is distorted according to the configuration of the gear teeth to crimp the yarn. A stuffer box process involves the forcing of yarn into apparatus having a constricted area so as to physically produce convolutions in the yarn and to crimp the yarn due to the constrictions and the forces applied to the yarn. A further process involves the passing of yarn around an edge having a particular radius of curvature so as to crimp the yarn. Yarns have also been textured by knitting same into a fabric, and after appropriate treatment, deknitting the fabric to obtain the crimped yarn. Furthermore, certain processes have been invented to chemically affect the molecular configuration of the polymer structure and thus produce a textured yarn. Yarn has also been subjected to the action of electrostatic forces, electromagnetic forces and supersonic pulses as the yarn passes through a treatment zone.

Utilization of one of the above mentioned techniques for altering the molecular configuration of the yarn in conjunction with heat treatment of the yarn, permits the active and latent characteristics of the yarn to be controlled or changed as desired. For example, the shape, lustre, cross sectional area, torque, resilience, residual shrinkage, texture, elasticity, stretch, stretch recovery and dimensional stability may be modified and/or controlled.

The very large majority of textured yarns being manufactured in the world today are processed according to one or more of the above mentioned systems to produce a stretch or bulk yarn depending upon the conditions of the process. Moreover, the patented prior art is replete with various and sundry modifications and improvements to the aforementioned texturing processes so as to improve the quality of the yarn being produced as well as the speed of processing, improve operating maintenance, reduce capital costs, and the like. Each of the above processes is, however, limited, especially with respect to processing speeds due to frictional engagement between the yarn and the apparatus for texturing same or some other physical limitation of the process conditions or apparatus employed.

The instant process and apparatus for texturing textile yarn represent a vast improvement over known texturing processes and apparatus and are not burdened by the physical shortcomings of the presently existing processes and apparatus. The present process permits the false twist texturing of multifilament yarns at speeds in excess of those being realized today, without adversely effecting the degree of texturing or the quality of textured yarn. Further, large denier yarn bundles may equally be processed according to the present invention.

There is no known prior art that in any way teaches or suggests the process and apparatus of the present invention. The closest known prior art is felt to be represented by U. S. Pats. Nos. 2,158,415 to Formbels; 2,442,880 to Schwartz; 2,468,826 to Kennedy et al.; 2,711,626 to Oglesby, Jr. et al.; 2,740,184 to Thomas; 2,855,750 to Schrenk et al.; 3,046,632 to Tsutsumi; 3,052,009 to Epstem et al.; 3,105,164 to Favrot; 3,107,478 to Arshinov et al.; 3,163,976 to Juillard; 3,268,971 to Lockwood, Jr.; 3,411,284 to Corbaz et al.; and 3,537,249 to Mayer, Jr.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved process for the texturing of multistrand textile materials.

Another object of the present invention is to provide a novel apparatus for the texturing of multistrand textile materials.

Still further, another object of the present invention is to provide a novel process for the false twisting of a multistrand synthetic fiber yarn.

Another object of the present invention is to provide a novel apparatus for the electrostatic false twisting of a multistrand synthetic fiber yarn.

Still another object of the present invention is to provide a novel process for the impartation of stretch or bulk qualities to a synthetic filament or fiber yarn.

Generally speaking, the present invention relates to a method for texturizing a multistrand textile material yarn comprising the steps of imparting sufficient electrical charge density to said strands to cause said strands to flare; and electrostatically driving the flared strands around a closed path to impart a false twist to the material as the material is fed thereby under controlled tension.

More specifically, a twist zone operating on an electrostatic principle is included in a texturing process line to impart twist to a multistrand yarn passing therethrough. Twist moves rearwardly against the direction of yarn travel and is set in conventional twist set means to produce a stretch yarn. Likewise conventional means may be employed downstream of the twist means to produce a bulk yarn.

A direct current voltage is applied to the strands, preferably at the entrance of a controlled atmosphere twist zone. The charge on the individual strands of the material is of like character and thus causes the individual strands to repel each other. The plurality of strands thus balloon or flare within the twist zone as the material passes therethrough. Tension on the material should be controlled to control flare of the strands and to permit the impartation of the false twist thereto. It should be understood that the term charge may refer to different phenomena. For example, the strand may be electrically semi-conductive or rendered so whereby the electrical charge is static; may be electrically insulative whereby it is necessary to build up sufficient electrical charge density to permit flare and twisting before dissipation of the charge; or may be electrically conductive or rendered so whereby the electrical charge is a moving charge with respect to the strand, said charge having sufficient density to cause the strand to repel adjacent strands having a moving charge of like polarity.

An electrical charge of opposite polarity to the charge on the strands is generated in the twist zone and mechanically or electrically moved around a closed path therein. The charged strands are attracted toward the opposite polarity driving charge and are driven around the closed path thereby. in addition, to the attractive driving force, certain embodiments of the driving electrical charge generator means simultaneously generate an electrical charge of like polarity to that on the charged filaments which repels the charged filaments in the direction of the attractive electrical charge. Hence, depending upon the selection of the electrical charge generator means, the driving force may be purely electrical attraction or a combination of electrical attraction and repulsion. Under either condition, as the charged strands move toward the driving electrical charge, the mutual repulsion among strands remains. Certain of the strands are thus closer to the driving electrical charge and are more under the influence thereof. Those strands furtherest away from the electrical driving charge thus lag behind the movement of the driving charge to cause twisting of'the strands and thus the textile materials. The twist imparted migrates from the twist zone to become set into the filaments by conventional means. Subsequent to the twist zone the charge on the strands is removed and the textile material moves to post heating or take up.

An enclosed twist zone is preferred according to the teachings of the present invention. Viscous drag of strands moving through air is subject to set up air currents which could be detrimental to the successful operation of the process. Hence a twist chamber is provided through which the textile material is fed and in which the flare of the strands occurs and false twist is imparted thereto. The chamber is preferably arranged to permit evacuation thereof and operation under reduced pressure conditions. Also, if desirable, various gases may be introduced into the twist chamber to realize certain effects. For example, it may be desirable under certain conditions to flood the twist chamber with one of the inert gases or it might be desirable to use a gas having a high dielectric constant to reduce the possibility of arcing, or the like. Such an enclosed twist zone thus affords additional flexibility to the process and apparatus of the present invention.

The textile materials that may be processed according to the present invention are those materials that may be textured. Such materials include the various synthetic theremo-plastic filaments and strands thereof as well as strands produced of natural fibers and blends of natural and synthetic fibers that have been pretreated to become susceptible to texturization. Moreover, as mentioned above, the material may be electrically insulative, semi-conductive or conductive, either by natural characteristics or by a finish applied thereto.

The initial electrical charge applied to the filaments or strands is produced by a direct current voltage source such that all filaments possess a like electrical charge, either positive or negative, though of possible variance in strength from filament to filament. Since like electrical charges repel each other, each filament attempts to repel all adjacent filaments, resulting in the flared yarn bundle. A driving electrical charge of opposite polarity to the charge on the filaments is generated in the twist zone which attracts the flared filaments. Individual filaments are attracted at varying degrees according to the magnitude of the charge thereon. Likewise, as mentioned above, in certain cases a repulsive force is also present which assists in moving the charged filaments in the direction of the opposite electrical charge. Movement of the said driving electrical charge around the closed path of the twist zone chamber, thus drives the charged filaments in a like path to impart the false twist to the yarn bundle. During passage of the flared yarn through the twist zone chamber, care should be taken to avoid contact between electrodes on which the said driving electrical charges are produced and the charged filaments. Control of tension on the yarn passing through the twist zone can avoid such contact and will also prevent collapse of the flare of the filaments.

During the impartation of false twist to a textile material according to the teachings of the present invention, tension on the material, the linear speed of the material, heating conditions, the speed of movement of the driving electrical charge and the magnitude of the strand charge and the driving charge are important variables. Control of at least certain of these variables enables the maximization of the instant process for a particular textile material.

Apparatus for conducting the present process may be conventional except for the strand charging and strand twisting means. In general the strand charging means include a source of direct current voltage, a conductive element for imparting the voltage to the strands and a conductive element of removal of the charge from the strands. The strand charging means may be independent of or may be incorporated with the twist zone chamber.

Strand twisting means generally include a power source to produce a driving electrical charge in the twist zone chamber. Means for moving the driving charge around a closed path within the twist zone chamber are also included. Though the driving charge may be mechanically or electrically moved around the close path, electrical movement is preferred. In fact a preferred strand twisting means for the present invention includes an even number of electrodes spaced in a closed path within the twist zone chamber and preferably around the inside wall of the twist zone chamber. The electrodes are operatively associated with circuitry which through a voltage phase shift arrangement, varies the maximum driving force from electrode to elec trode to drive the strands around the closed path. The twist zone chamber may also be adapted to operate under different atmosphere conditions as discussed hereinbefore.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a line drawing of an embodiment of the process and apparatus according to the teachings of the present invention.

FIG. 2 is a line drawing of another embodiment of the process and apparatus according to the teachings of the present invention.

FIG. 3 is a vertical cross sectional view of a twist zone according to the teachings of the present invention showing the yarn in a flared condition and attracted toward a portion of the chamber wall.

FIG. 4 is a side elevational view of the twist zone according to the teachings of the present invention showing a further embodiment thereof.

FIG. 5 is a horizontal cross sectional view of the twist zone according to the teachings of the present invention showing the yarn in a flared condition and attracted to a portion of the chamber wall.

FIG. 6 is a schematic electrical diagram of a preferred arrangement for a rotating alternating current field device for use according to the teachings of the present invention DESCRIPTION OF THE PREFERRED EMBODIMENTS Textile materials that may be textured according to the present process include all types of yarns, tows, etc. that may per se, be textured. Such materials generally include multi-filament synthetic, thermoplastic yarns and strands produced from synthetic fibers and blends of synthetic and natural fibers. Likewise, multiple strands of natural fibers that have been pretreated may be textured by the present apparatus and process. For example, polyamides, polyesters, acrylics and the like are exemplary of the types of synthetic filaments that may be very suitably processed according to the teachings of the present invention. Such yarns should be multifilament or multistrand to produce a yarn bundle. Moreover, the process of the present invention may be utilized so as to produce a stretch yarn or a set, bulk yarn as desired.

The apparatus of the present invention is ideally suited for use in conjunction with existing process equipment or as an independent item of process equipment. For example, yarn to be processed according to the present invention may be fed from an extrusion system directly to the texturing apparatus of the present invention. Likewise, yarn may be supplied from a package of drawn or undrawn yarn, or may be processed on a draw twister, draw winder, or the like that embodies the novel apparatus and process of the present invention. In other words, due to the speed capability and low capital costs, the apparatus of the present invention may be employed equally well by the fiber producer, throwster, or the like.

Referring to the Figures, specific embodiments of the present invention will now be described in detail. In Figure 1, there is shown a preferred arrangement for false twist texturing of yarns. A yarn Y having a plurality of filaments F is removed from a yarn supply source generally indicated as 10 by feed means (shown as nip rolls), past a heater means 30, a cooling zone generally indicated as 35, a filament charge section generally indicated as 40, a false twist zone generally indicated as 50, optional feed means 60, an optional hcatcr 65 (shown in phantom), second feed means 70 and a yarn take up means generally indicated as 80.

Yarn feed means 20, and 70 serve several possible functions, and may take several configurations other than the nip rolls shown in FIG. 1. For example, feed means 20 and 60 or 70 provide power for movement of a yarn through the apparatus, act as twist stops upstream and downstream respectively from twist zone 50, control tension in the yarn, and the like. Moreover, feed means 20, 60 and 70 may be heated rolls to serve as pre and post heaters for the yarn. Optional feed means 60 may be employed in conjunction with heater means if it is desirable to produce a bulk yarn. In such an arrangement feed means 60 is utilized to control yarn speed and tension in the twist zone and is also coordinated with feed means to control yarn tension in the second heat zone. Numerous feed means are well known in the art and the particular configuration thereof is well within the purview of one skilled in the art. Moreover, twist stop means may be independent of the feed means if desired. Driven nip rolls are, however, preferred.

Heater means 30, and heater means 65 (shown in phantom as being optional) are also well known to those skilled in the texturing art. As such, depending upon the particular situation, heater means 30 and 65, if employed, may be space heaters, a heated liquid, heated godets, strip heaters, tube heaters, radio frequency heaters, or the like. Heat may thus be supplied to the yarn by radiation, conduction or the like.

The yarn or strand charge zone 40 precedes the twist zone 50 and contains an electrically conductive element 41 for applying an electrical charge to the filaments F that make up yarn Y and a conductive element 44 for neutralizing the charged filaments after twisting. Conductive element 41 is operatively associated with a direct current generator 42 by a suitable connector 43. Yarn Y passes element 41 where the individual filaments F receive an electrical charge of a certain polarity. Once filaments F receive an electrical charge at element 41, each filament tends to repel adjacent filaments F since they all have the same polarity electrical charge. As yarn tension and space permits, the filaments flare outwardly. Conductive element 41 may be separate from twist zone 50 or a part thereof as will be described in detail hereinafter. Moreover, conductive element 41 may be a conductive wear resistant metal, ceramic or plastic as desired and the shape of same may be determined by the prerequisites of the particular yarn being textured. A tubular beryllium-copper 0 stainless steel element is preferred.

The DC. generator 42 should preferably be a variable voltage generator since the magnitude of voltage required to produce a satisfactory filament flare will vary with the number of filaments, the degree of conductivity of the filaments, the linear speed of yarn travel and the like. A Van de Graaff generator or the like is quite acceptable for certain purposes. A variable voltage supply with outputs of from about 5,000 to about 100,000 volts is generally acceptable. Second conductive element 44 is present at or adjacent the exit end of the twist zone 50 and, like element 41 is operatively associated with direct current generator 42 through a conductor 45. Conductive element 44 transmits electrical charges of opposite polarity to that of element 41 and when engaged by filaments F, neutralizes the charge thereon or conveys the charge from filaments F. Hence after the false twist is imparted thereto, the electrical charge on the yarn bundle is removed.

As mentioned earlier, depending upon the degree of conductivity of the yarn, different types of electrical charges are present. Hence conductive elements 41 and 44 will provide a different mechanism for a truly conductive yarn, by continually passing direct current voltage therethrough. The electrical charge, though moving with respect to the yarn, would have sufficient charge density to cause the filaments to flare.

After receiving an electrical charge of a sufficient density, yarn Y next passes into the twist zone 50. As mentioned earlier, ambient air currents, viscous drag of the filaments through the air and the like can adversely affect the operation of the present process. A twist zone chamber 51 is thus preferably provided in which atmospheric conditions can be controlled. Chamber S1 is preferably cylindrical in shape though other geometric configurations are quite acceptable. Chamber 51 is thus also provided with a yarn entrance S2 and a yarn exit 53. Entrance 52 and exit 53 are preferably seals or restrictors to enable accurate control of the atmosphere within the chamber. Further, entrance 52 may have integral therewith as shown in FIG. 1, conductive element 41 of charge zone 40 and exit 53 may have integral therewith conductive element 44 that is also electrically connected to generator 42 by a connector 45. Element 44 as mentioned above neutralizes the charge on filaments F. Elements 41 and 44 are both preferably beryllium-copper or stainless steel tubular members having flared ends thereon. Chamber 51 is manufactured of a non conductive material, preferably a plastic material such as a plexiglas, a polycarbonate, or the like and has a connection 54 to which is affixed a tubular member 55. Tubular member 55 is operatively associated with a control means C which maintains the proper predetermined atmosphere within chamber 51.

The electrical strand twisting means of the present invention comprise a source of power, a driving electrical charge generator means and a driving charge moving means. Generally the driving charge is generated on one or more electrodes and the electrodes are mechanically moved around a closed path or the charge is generated on at least one of a plurality of electrodes and the charge is mechanically or electrically moved around the path of electrodes. In FIG. I, a plurality of electrodes 56 are spaced about the inner periphery of chamber 51. Electrodes 56 are insulated from each other and operatively associated with a driver electrical charge generator and moving means S. A preferred embodiment of the electrical strand twisting means of the present invention combines the driver charge generator and moving means into one electrical unit though as pointed out above the generator and driver means may be separate and the mover means may be mechanical or electrical. Thus according to the embodiment shown in FIG. I, a driving charge is created on at least one of the electrodes 56 and this charge is sequentially moved from electrode to electrode to drive charged filaments F around the inner periphery of chamber 51. A preferred embodiment of the driving charge generator and moving means will be described in detail hereinafter.

Electrodes 56 may be arranged according to the dietates of the particular end result being sought. For example, the number of electrodes required will be dependent upon the arrangement for generating and mov ing the driving electrical charge. Moreover, the size and shape of the electrodes could likewise be varied according to the dictates of the yarn being processed, the linear speed of yarn travel, the desired number of turns per inch and the like. Preferably electrodes 56 are positioned around the inside wall of chamber 51 though other positions are acceptable. It should be realized, however, that a much greater driving electrical charge will be required when the electrodes are moved away from close proximity to the filaments.

Referring to FIG. 4, a plurality of electrodes 356 are shown in a twist zone chamber 351, the electrodes having a hyperbolic type curvature as opposed to the straight electrodes 56 of FIG. I. Electrodes 356 thus more closely follow the balloon contour of the flared filaments F and bring the driving electrical force closer to the overall segment of the yarn in the twist zone. The magnitude of the driving electrical force is inversely proportional to the square of the distance between the force and an object being acted upon. Hence by utilizing the electrode configuration as shown in FIG. 4, a greater driving force may be applied to filaments F. A greater number of turns of twist per inch may thus be imparted to the yarn, less overall force is required for the same twist, the yarn may be fed at a greater linear speed, or the like.

The driving charge generator and moving means may take several forms as has been mentioned hereinbefore. For example, the driving charge may be represented by direct current voltage on an electrode by utilizing slip rings, commutators or the like. Thereafter the chamber 51 or the electrodes 56 may be moved mechanically to drive filaments F around the closed path. This situation, however, involves moving mechanical parts and though successful, is not preferred since some of the limitations of the prior art appear. It is thus preferred according to the teachings of the present invention to combine the driving charge generator means and the driving charge moving means whereby both chamber 51 and electrodes 56 remain stationary and the driving charge or charges are mechanically or electrically moved from electrode to electrode in sequential fashion. Such an arrangement involves no moving parts in the twist chamber 51. Electrical switching is most preferred and will be described in greater detail with respect to FIGS. 5 and 6 where an alternating current electric field is electrodynamically rotated about the electrode path.

In the event a second heater means 65 (shown in phantom in FIG. 1) is employed, the optional feed means 60 are likewise employed. In such an arrangement, the speed of feed means 60 is set and feed means 20 is varied to control speed and tension of yarn Y passing through twist zone 50. Likewise feed means is varied with respect to feed means 60 to control tension on the yarn at heater means 65. For example, feed means 70 may be adjusted with respect to feed means 60 to overfeed yarn Y at heater means 65 whereby heater means 65 produces a bulk yarn. Likewise, other conditions may be instituted to control the final condition of yarn Y.

Subsequent to second roll means 70, yarn Y is taken up by suitable means and carried to further processing.

FIG. 2 illustrates a further embodiment of the present invention. A yarn supply source is shown, followed by a finish applicator unit 115, a draw zone generally indicated as 117, a feed means 120, heater means 130, cooling zone 135, charge zone 140, twist zone 150, optional feed means 160, second heater means 165 (in phantom), second feed means 170 and yarn take up means 180. Each of the means of FIG. 2 that are duplicated in FIG. I are suitable as described with respect to FIG. 1. Additionally, finish applicator unit 115 is added to apply an electrically conductive finish onto the filaments F of yarn Y so as to render the filaments suitable for accepting an electrical charge as defined herein in charge zone 140. Further the yarn Y of FIG. 2 is previously undrawn. A draw zone 117 is thus provided to draw the yarn as described prior to texturing. Apparatus of draw zone 117 is well known to one skilled in the art and suitable draw apparatus may be employed in tandem with the texturing apparatus as shown in FIG. 2.

FIG. 3 illustrates yarn flare within a chamber 251 of a twist zone 250. Upon receiving an electrical charge at conductive element 241, individual filaments F of yarn Y immediately seek to repel each other. The restrictive dimension of the preferred tubular element 241 prevents repulsion until the yarn is within chamber 251. Once within chamber 251, the filament would normally balloon in all directions (not shown). When, however, the driving electrical force is generated at electrodes 256, then the oppositely charged filaments move into the quadrants nearest the most powerful attractive force (See FIG. 5). Electrical charges on filaments F are approximately equal, and the filaments are drawn closer to electrodes 256 having opposite polarity while remaining in a flared condition. Also, in certain arrangements, a driving electrical charge of like polarity to that on filaments F is present at the opposite side of the twist chamber from the attractive driving charge. The like polarity driving charge thus tends to repel filaments F into the quadrants nearest the attractive driving charge. Hence the driving charge for this particular arrangement is a combination of repulsion and attraction of filaments F. As the driving electrical charge moves around chamber 251, the filaments closest to electrodes 256 will follow immediately while the filaments further away from electrodes 256 lag behind in linear speed. Movement of the driving charge around the closed path thus drives the charged filaments F in the same path and yarn Y is twisted.

FIG. 5 shows a cross section of a twist zone chamber having 18 consecutively numbered electrodes equally spaced along the inner chamber wall. A preferred means for generating and moving a driving electrical charge around the eighteen electrodes is a rotating alternating current field which is produced by a phase shifting network to shift the maximum voltage potential successively from electrode to electrode to drive filaments F around chamber 51 and impart false twist to yarn Y. Such an arrangement would produce voltage simultaneously at all of the electrodes, but of different potential. Further, with an even number of electrodes and geometrically opposite electrodes being coupled, one of the electrodes is always at an opposite polarity to the other of the pair. For example, when electrode 1 has maximum positive potential, negatively charged filaments F would be attracted thereto. Simultaneously, electrode would be at maximum negative potential and would repel filaments F in the direction of electrode 1. Hence in this situation the electrical driving force would be a combination of attractive and repulsive electrical'forces.

Phase shifting of the voltage from electrode pair to electrode pair would thus move the maximum potential sequentially around the electrode path, driving the filaments F therewith. Filaments F remain flared while being driven around the closed path thus twisting yarn Y and imparting torque thereto. In FIG. 5, the filaments F are shown adjacent electrode 1, and sequential movement of maximum potential in a clockwise fashion would produce S twist upstream of the twist zone to be set into the yarn in the heating and cooling zones.

A phase shift network may be very successfully employed to produce the rotating alternating current electrical field, and is preferred. As mentioned earlier, however, numerous arrangements may be employed for generating the driving electrical charge and moving same around the closed path. Referring again to FIG. 5 and also to FIG. 6, an example of an entire driving electrical force generator and moving means will be described. FIG. 6 illustrates a particular phase shift network for the eighteen electrodes as shown in FIG. 5. An oscillator amplifier 200, integrated

circuit amplifiers

202, 204 and their counterparts in subsequent circuitry receive primary power from direct current supply 201. Amplifier 202 thus supplies voltage to power amplifier 204 which along with its associated circuitry is referred to as driver Dl. Subsequent drivers D2, D3, D4, D5, D6, D7, D8 and D9 are of like value to driver D1 and each is electrically associated with its own transformer, T1 through T9 respectively with each transformer being connected to two geometrically opposite electrodes, e.g., l and 10, 2 and 11, etc. Voltage is supplied from amplifier 202 to dual amplifier DPAl and in turn to dual preamplifiers DPA2, DPA3 and DPA4, preamplifier PAS and returned to oscillator amplifier 200 where the voltage is inverted. Dual amplifier DPAl is provided with two capacitator-resistor phase shifting circuits, a preamplifier being associated with each. The first of said preamplifiers supplies voltage to the capacitator-resistor circuit of the second preamplifier.

Voltage output from each preamplifier thus provides input to its respective driver amplifier and the next adjacent capacitator-resistor circuit. The voltage input to each capacitator-resistor circuit is shifted in phase by a predetermined amount dependent upon the number of electrodes in the twist zone, 20 according to FIG. 6. Hence as the voltage shifts in phase, the maximum voltage potential shifts from electrode to electrode, thus driving filaments F by both attractive and repulsive forces around chamber 51. Preamplifier PAS provides feedback to oscillator amplifier 200 which inverts the voltage to complete the 360 phase shift. The maximum voltage potential sequentially moves from one electrode to the next as the alternation of the voltage input to the amplifier progresses with time.

A better understanding of the present invention may be had by reference to the following example.

EXAMPLE 1 Apparatus was arranged as shown in FIG. 1 without heaters and using a mechanical step switch arrangement for generating and moving the driving electrical charge. A drawn polyethylene terephthalate yarn denier, 32 filaments), was padded with a 20 per cent aqueous solution of the potassium salt of mono and dihexyl phosphate. After drying, the yarn was fed to the twist zone chamber at 50 meters per minute under tension conditions to permit filament flare while prevent ing contact between the filaments and the electrodes. A Van de Graaff generator supplied approximately 50,000 volts to a beryllium-copper tube at the entrance of the cylindrical twist chamber constructed of Plexiglas. The chamber had 24 equally spaced electrode strips secured around the inner wall thereof with a l megohm resistor connecting adjacent electrodes. Mechanical switches were connected to two electrodes l80 apart to simulate a rotating alternating current field. As the charged polyester yarn passed into the twist chamber, the individual filaments flared outwardly in all directions. Direct current voltage was then passed through the appropriate switch to electrodes 1 and 13, with electrode 1 being most positive and 13 most negative. All of the filaments immediately moved in the direction of electrode 1 and assumed a configuration similar to that shown in FIG. 5 of the drawings. Through the mechanical switching, the direct current was moved to

electrodes

2 and 14, t 3 and 1S and so on. As the direct current voltage was manually switched from one electrode pair to the next electrode pair, the flared bundle of filaments was driven in a like manner and direction. Continuous manual switching enabled the impartation of false twist to the yarn bundle.

Having described the present invention in detail, it is obvious that one skilled in the art will be able to make variations and modifications thereto without departing from the scope of the invention. Accordingly, the scope of the present invention should be determined only by the claims appended hereto.

What is claimed is:

1. A method of applying a false twist to a textile material having a plurality of strands comprising the steps of:

a. continuously feeding said material under a predetermined amount of tension to a charge zone;

b. applying an electrical charge to strands of said moving material to cause said strands to repel each other and produce a flare in said material; and

c. electrically driving the charged, flared strands around a closed path during movement thereof, whereby a false twist is imparted to said material.

2. A method of false twisting a textile material as defined in claim 1 wherein the textile material is a multi filament, thermoplastic yarn.

3. A method of false twisting a textile material as de-.

fined in claim 1 wherein further a conductive finish is applied to said textile material prior to applying the charge thereto.

4. A method of false twisting a textile material as defined in claim 2 wherein the material is heated and cooled before twisting and heated after twisting to produce a bulk yarn.

5. A method of false twisting a textile material as defined in claim 1 wherein the electrical charge is applied at the entrance to a controlled atmosphere twist zone.

6. A method of false twisting a textile material as defined in claim 5 wherein the electrical charge is applied by a direct current generator.

7. A method of false twisting a textile material as de- 6 fined in claim 1 where the strands are electrically driven around a closed path by generating an attractive electrical charge adjacent the moving flared strands and moving said attractive electrical charge in a closed path.

8. A method of false twisting a textile material as defined in claim 7 wherein the attractive electrical charge is mechanically moved around the closed path.

9. A method of false twisting a textile material as defined in claim 7 wherein the attractive electrical charge is electrically moved around the closed path.

10. A method of false twisting a textile material as defined in claim I wherein the flared strands are electrically driven around a closed path by an alternating current field rotating about said closed path.

11. A method of applying false twist to an indeterminate length of multifilament synthetic yarn comprising the steps of:

a. applying a conductive finish to said yarn;

b. applying an electrical charge to said yarn;

c. passing said yarn under controlled tension conditions into a controlled atmosphere area where charged filaments thereof repel each other and produce a flare in the yarn, and

d. electrically driving said moving flared filaments around a closed path whereby a false twist is imparted to said yarn.

12. A method of false twisting a multifilament synthetic yarn as defined in claim 11 wherein said yarn is heated and cooled prior to being given an electrical charge, twist in said yarn backing up into the area where the yarn is heated to set the yarn in the twisted configuration.

13. A method of false twisting a multifilament synthetic yarn as defined in claim 11 wherein further said yarn is heated after twisting.

14. A method of false twisting a multifilament synthetic yarn as defined in claim 11 wherein a yarn is charged by passage through an electrically conductive element, said element being in electrical connection with a direct current generator.

15. A method of false twisting a multifilament synthetic yarn as defined in claim 11 wherein said controlled atmosphere area is maintained at a reduced pressure.

16. A method of false twisting a multifilament synthetic yarn as defined in claim 11 wherein the electrical driving force is provided by a rotating alternating current field.

17. A method of false twisting a multifilament synthetic yarn as defined in claim 11 wherein said yarn is drawn prior to being given an electrical charge.

18. False twisting apparatus comprising:

a. an electrically conductive element;

b. an electrical charge source operatively associated with said element;

c. a twist zone chamber adjacent said conductive element, said chamber having a material path therethrough; said chamber further having at least one electrode spaced therein and associated therewith;

d. an electrical driving force generator means operatively associated with said at least one electrode; and

e. means to move said electrical driving force in a closed path.

19. False twisting apparatus as defined in claim 18 comprising further yarn feed means located upstream of said charging element and yarn take up means located downstream of said twist zone chamber.

20. False twisting apparatus as defined in claim 18 wherein said conductive element forms at least a part of a material entrance to said twist zone structure.

21. False twisting apparatus as defined in claim 18 wherein said electrical charge source is a direct current generator.

22. False twisting apparatus as defined in claim 18 wherein said electrical driving force generator and moving means is a rotating alternating current field and wherein a plurality of electrodes are associated with said twist zone structure forming a closed path therein.

23. False twisting apparatus as defined in claim 18 comprising material feed means located before and after said twist zone structure.

24. False twisting apparatus as defined in claim 23 comprising further heater means located between said first material feed means and said twist zone chamber.

25. False twisting apparatus as defined in claim 24 comprising further heater means located after said twist zone structure, said further heater means being located between feed means positioned downstream of said twist zone structure.

26. False twisting apparatus comprising:'

a. yarn supply means;

b. a pair of nip rollers positioned downstream of said yarn feed means;

c. a yarn heater positioned downstream of said nip rollers;

d. a twist zone chamber located downstream of said yarn heater, said twist zone chamber having a yarn inlet element and a yarn outlet element, said chamber further having a plurality of electrodes associated therewith at least partly around a closed path defined by said chamber;

e. an electrical charge generator means in electrical connection with said yarn inlet element of said twist zone chamber, to charge said filaments as they pass therethrough to cause said filaments to flare in said twist zone chamber;

f. electrical driving force generator and moving means operatively associated with said electrodes whereby said filaments in the flared state are attracted to said electrodes and are moved around said closed path to impart twist to said yarn;

g. a pair of nip rollers positioned downstream of said twist zone chamber; and

h. yarn take up means located downstream of said nip rollers.

27. Apparatus for false twisting a multifilament synthetic yarn as defined in claim 26 comprising further a yarn heater positioned between said twist zone structure and said downstream nip rollers, and a further pair of nip rollers positioned between said heater and said twist zone chamber.

28. False twisting apparatus as defined in claim 26 wherein said twist zone chamber is provided with restrictive orifices at each end to throttle the atmosphere at both ends thereof and wherein said chamber has internal pressure control means associated therewith.

29. False twisting apparatus as defined in claim 26 wherein said electrical driving force generator and moving means is a rotating alternating current field generator.

30. False twisting apparatus as defined in claim 26 comprising further finish applicator means positioned between said yarn supply means and said yarn heater.

31. A twist zone structure comprising a chamber, said chamber having end walls and at least one side wall defining a substantially enclosed structure, said end walls having yarn passageways therethrough, said passageways being throttled to control air passage therethrough, and aplurality of electrodes associated with said at least one side wall, said electrodes defining a closed path within said chamber.

32. A twist zone structure as defined in claim 31 wherein further, a tubular, electrically conductive element is received in the yarn passageway in each end wall of said chamber.

33. A twist zone structure as definedin claim 31 wherein further, electrical charge generator means and electrical charge movement means are operatively associated with said electrodes.

34. A twist zone structure as defined in claim 31 wherein said chamber further has pressure control

Claims

1. A method of applying a false twist to a textile material having a plurality of strands comprising the steps of: a. continuously feeding said material under a predetermined amount of tension to a charge zone; b. applying an electrical charge to strands of said moving material to cause said strands to repel each other and produce a flare in said material; and c. electrically driving the charged, flared strands around a closed path during movement thereof, whereby a false twist is imparted to said material.

2. A method of false twisting a textile material as defined in claim 1 wherein the textile material is a multi-filament, thermoplastic yarn.

3. A method of false twisting a textile material as defined in claim 1 wherein further a conductive finish is applied to said textile material prior to applying the charge thereto.

7. A method of false twisting a textile material as defined in claim 1 where the strands are electrically driven around a closed path by generating an attractive electrical charge adjacent the moving flared strands and moving said attractive electrical charge in a closed path.

10. A method of false twisting a textile material as defined in claim 1 wherein the flared strands are electrically driven around a closed path by an alternating current field rotating about said closed path.

11. A method of applying false twist to an indeterminate length of multifilament synthetic yarn comprising the steps of: a. applying a conductive finish to said yarn; b. applying an electrical charge to said yarn; c. passing said yarn under controlled tension conditions into a controlled atmosphere area where charged filaments thereof repel each other and produce a flare in the yarn; and d. electrically driving said moving flared filaments around a closed path whereby a false twist is imparted to said yarn.

18. False twisting apparatus comprising: a. an electrically conductive element; b. an electrical charge source operatively associated with said element; c. a twist zone chamber adjacent said conductive element, said chamber having a material path therethrough; said chamber further having at least one electrode spaced therein and associated therewith; d. an electrical driving force generator means operatively associated with said at least one electrode; and e. means to move said electrical driving force in a closed path.

26. False twisting apparatus comprising: a. yarn supply means; b. a pair of nip rollers positioned downstream of said yarn feed means; c. a yarn heater positioned downstream of said nip rollers; D. a twist zone chamber located downstream of said yarn heater, said twist zone chamber having a yarn inlet element and a yarn outlet element, said chamber further having a plurality of electrodes associated therewith at least partly around a closed path defined by said chamber; e. an electrical charge generator means in electrical connection with said yarn inlet element of said twist zone chamber, to charge said filaments as they pass therethrough to cause said filaments to flare in said twist zone chamber; f. electrical driving force generator and moving means operatively associated with said electrodes whereby said filaments in the flared state are attracted to said electrodes and are moved around said closed path to impart twist to said yarn; g. a pair of nip rollers positioned downstream of said twist zone chamber; and h. yarn take up means located downstream of said nip rollers.

31. A twist zone structure comprising a chamber, said chamber having end walls and at least one side wall defining a substantially enclosed structure, said end walls having yarn passageways therethrough, said passageways being throttled to control air passage therethrough, and a plurality of electrodes associated with said at least one side wall, said electrodes defining a closed path within said chamber.

33. A twist zone structure as defined in claim 31 wherein further, electrical charge generator means and electrical charge movement means are operatively associated with said electrodes.

34. A twist zone structure as defined in claim 31 wherein said chamber further has pressure control means in operative communication with the interior thereof.