US3791130A - Method for false-twisting a synthetic filament yarn - Google Patents

Method for false-twisting a synthetic filament yarn Download PDF

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Publication number
US3791130A
US3791130A US00193331A US19333171A US3791130A US 3791130 A US3791130 A US 3791130A US 00193331 A US00193331 A US 00193331A US 19333171 A US19333171 A US 19333171A US 3791130 A US3791130 A US 3791130A
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yarn
closed path
false
pin
filament
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US00193331A
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English (en)
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Y Chiba
H Inuyama
S Tomioka
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Toray Industries Inc
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Toray Industries Inc
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    • D—TEXTILES; PAPER
    • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
    • D02G1/00—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics
    • D02G1/02—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics by twisting, fixing the twist and backtwisting, i.e. by imparting false twist
    • D02G1/0206—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics by twisting, fixing the twist and backtwisting, i.e. by imparting false twist by false-twisting
    • D02G1/0266—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics by twisting, fixing the twist and backtwisting, i.e. by imparting false twist by false-twisting false-twisting machines

Definitions

  • the yarn is heated at a temperature at which the yarn is pla'sticized.
  • the yarn is then passed through a closed path formed around a pin while contacting the periphery of the pin.
  • a portion of the yarn emerging from the closed path is brought into contact with a portion of the yarn entering the closed path.
  • the entering and the emerging portions of the yarn are entwined with each other at entry and exit regions of the closed path in such a manner that each portion of the yarn goes around the other in at least one turn under friction while travelling in the same direction.
  • the present invention relates to a method and apparatus for false-twisting a synthetic filament yarn, more particularly, relates to a method and apparatus for false-twisting a thermoplastic synthetic monoor multifilament yarn so as to result in a textured yarn having a high torque and little or no crimp.
  • the synthetic filament yarn is false-twisted by using a spindle and there is an upper limit to the rotation number of the spindle, hence, there is an upper limit to the velocity of processing of the false-twisting.
  • the productivity of the textured yarn from fine denier filament yarn is relatively low.
  • the conventional friction drive method for falsetwisting the filament yarn can be carried out with a high productivity at a large twist number.
  • this method has the disadvantages that the friction member used for false-twisting the filament yarn must be made of a special hard material having a high resistance against rubbing and that it is very difficult to control the twist number for the filament yarn because the frictional property of the frictional member varies owing to transfer of the oiling agent applied to the filament yarn to the friction surface thereof.
  • the textured yarns produced by the abovementioned conventional false-twisting method have a high bulkiness due to the highly crimped filaments, but the torque is relatively low.
  • the conventional false-twisting method can produce a textured filament yarn having a high crimp and bulkiness but can not provide a textured yarn having a high torque and little or no crimp.
  • Such textured yarn having a high torque and little or no crimp is suitable for knitted articles, especially, hosiery, and more especially, stockings.
  • the knitted articles high stretchability, a beautiful appearance and an elegant hand feeling.
  • the high torque textured filament yarns have been recently spot-lighted and demand for them increases.
  • An object of the present invention is to provide a method and apparatus for false-twisting a synthetic filament yarn into a textured yarn having a high torque and which are substantially no crimp.
  • Another object of the present invention is to provide a method and apparatus for false-twisting a synthetic filament yarn at a high processing velocity into a textured yarn having a high torque.
  • a further object of the present invention is to provide produced from the high torque textured yarn have a a method and apparatus for false-twisting a synthetic vention.
  • the method of the' present invention includes the step of heating a synthetic monoor multi-filament yarn at a temperature at which the yarn is plasticized by passing the yarn through the heating means, and the step of false-twisting the yarn by passing the yarn through a closed path formed around a pin, the yarn enters into and emerges from the closed path while contacting the periphery of the pin, and, at entry and exit regions of the closed path, a portion of the yarn entering into the closed path and a portion of the yarn emerging from the closed path are entwined with each other in at least one turn under friction while travelling in the same direction, whereby the entering portion of the yarn is twisted by the forward travel of the emerging portion and a portion of the yarn emerged from the closed path is untwisted by the forward travel of the entering portion.
  • the apparatus of the present invention comprises a feed means for a monoor multi-filament yarn, heating means for the yarn disposed downstream of the feed means, means for defining a closed path for the yarn disposed downstream of the heating means and containing at least one pin on the periphery ofwhich a portion of the yarn entering into the closed path and a por tion of the yarn emerging from the closed path are entwined with each other in at least one turn, and delivery means for the yarn disposed downstream of the closed path-defining means.
  • the filament yarn is uniformly false-twisted under a predetermined condition.
  • the false-twisted filament yarn is sufficiently heatset at the twisted form and thereafter, untwisted.
  • the filament yarn is deformed at a high torsion and low flexure.
  • the twist number of the resultant false-twisted yarn depends on the travelling velocity of the yarns, intersecting angle between the yarns, filament number in the yarns, and diameter and frictional efficiency of the yarn.
  • T represents the twist number in turns/m
  • V the velocity in m/min of yarn emerging from the entwining region
  • V the velocity in m/min of the yarn entering into the entwining region
  • B the frictional coefficiency of the yarn
  • 0 the twine angle between the entering portion and the emerging portion of the yarn
  • a the shrinkage of the yarn due to twist of the yarn which is equal to V V V.
  • the twine angle 6 of the yarn used herein means an angle between the axis lines of each of the yarns entwined with each other
  • the frictional coefficient [3 is a variable which varies with the frictional coefficient, contact area and contact pressure of the yarns entwined with each other. That is, the diameter, filament number and frictional coefficient of the yarns depend on the kind of the filament yarns used, hence, in the case where preselected filament yarns are false-twisted at a predetermined velocity, the twist number can be adjusted by controlling the twine angle and contact area and pressure between the yarns twined with each other.
  • the contact pressure of the yarns can be adjusted by controlling the tension on the filament yarns.
  • the twine angle is adjusted by controlling the cross angle between the portion of the yarn just entered into the closed path and the portion of the yarn just emerged from the closed path. Accordingly, the twist number can be adjusted by controlling the cross angle as defined above and the tension of the yarns. The method of controlling the cross angle will be illustrated in detail hereinafter.
  • the filament yarn to be false-twisted is heated at a temperature at which the yarn is plasticized and then passed through a closed path, and at entry and exit region of the closed path, the entering portion and the emerging portion of the yarn are entwined with each other in at least one turn under friction.
  • the entering and emerging portions of the yarn intersect each other so as to make contact substantially at one point.
  • the entering and emerging portions of the yarn are entwined with each other so as to make contact over a certain length. Therefore, it is obvious that the frictional efficiency [3 in the method of the present invention is higher than that of the conventional method.
  • Such high frictional efficiency derived from the method of the present invention results in a twist number greater than that of the conventional method.
  • the entering and emerging portions of the yarn are pressed to each other at the region in which they are twined with each other so as to enhance the frictional efficiency [3, and hence, to increase the twist number.
  • the pressure on the portions of the yarn in the twine region of the closed path causes a decrease of bending of the yarn in the twisting process. Therefore, in the false-twisting process according to the present invention, the filament yarn is highly twisted and slightly bent, and the filaments in the yarn slightly migrate owing to the pressure. Such slight bending of the yarn and migration of the filaments in the false-twisting process is very effective for preventing the yarn from crimping. Also, the high twist of the yarn results in an enhanced torque of the yarn.
  • the portion of yarn travelling toward the closed path is heated by the heater located upstream of the closed path at a temperature at which the yarn is plasticized and then cooled between the heater and the closed path while being twisted by the forward travel of the portion of the yarn emerging from the closed path. Accordingly, the portion of the yarn travelling toward the closed path is heat-set in the twisted form at a region upstream of the closed path. Next, the twisted and heat-set portion of the yarn enters into the closed path and is untwisted in the entry region of the closed path by the forward travel of the emerging portion of the yarn.
  • the filament in the yarn is certainly migrated and bent outwardly so as to increase the diameter of the yarn.
  • the filament in the yarn is prevented from migration and bending so as not to increase the diameter of the yarn. This results in the high torque and low crimp of the textured yarn obtained from the method of the present invention.
  • Textured yarn having an optimum torque can be prepared by false-twisting at an optimum twist number which depends on the total denier of the yarn and number of filaments in the yarn. That is, if the twist number is excessively large the resultant textured yarn has undesired crimp, and if the twist number is excessively low, the resultant textured yarn has a non-uniform torque.
  • nylon 66 filament yarns having filament counts of 17 denier/3 filaments, 20 denier/2 filaments, 2O denier/3 filaments, 22 denier/3 filaments, 25 denier/3 filaments and 25 denier/5 filaments, were false-twisted by the method of the present invention at various twist numbers, and crimping property of the resultant textured yarns and evenness of knitted fabric from the resultant textured yarns were observed.
  • the multi-filament yarn is twisted at a twist number satisfying the following relationship (II):
  • T represents the twist number in turn/meter
  • the optimum twist number for the filament yarn is selected in consideration of the use of the resultant textured yarn. If it is desired that the textured yarn has a very high torque, the filament yarn is false-twisted at the upper limit of the twist number satisfying the relationahip (11). However, if it is desired that the textured yarn has a relatively low torque, the filament yarn is false-twisted at a relatively low twist number satisfying the relationship (11).
  • the yarn is twisted at the twist number satisfying the following relationship (Ill).
  • the resultant textured yarn has no crimp.
  • the present invention provides a method and device for adjusting the cross angle between a portion of the yarn just entered into the closed path and a portion of the yarn just emerged from the closed pass in order to control the twist number of the yarn.
  • FIG. 1 is aschematic view of an embodiment of the apparatus of the present invention
  • FIGS. 2A and 2B are schematic views showing the relationship between the direction of entwining of yarns and the direction of twisting of the yarns
  • FIG. 3 is a schematic view ofanother embodiment of the apparatus of the present invention.
  • FIGS. 4A, 4B and 4C are all schematic views showing the relationship between the position of a rotatable roller in the closed path the cross angle d) between a por- 6 tion of yarn just entered into the closed path and a portion of yarn just emerged from the closed path in the apparatus of FIG. 3,
  • FIGS. 5A and 5B are both schematic views showing the relationship between the diameter of the fixed pin and the cross angle :12 in the apparatus of FIG. 1,
  • FIG. 6 is a schematic view showing the relationship between the position of the fixed pin and the cross angle (1:,
  • FIG. 7 is a graph showing the relationship between the cross angle (1) and twist number
  • FIG. 8 is a graph showing the relationship between the diameter of the fixed pin and twist number
  • FIG. 9 is a graph showing the relationship between the denier of the filament yarn and twist number
  • FIG. 10 is a schematic view showing a conventional false-twisting method other than the method of the present invention.
  • a filament yarn 2 is fed by means of a pair of feed rollers 4 from a feed package 1 onto the heater 5 through a guide 3.
  • the yarn 2 is heated by the heater 5 to a temperature at which the yarn 2 is plasticized, cooled downstream of the heater 5 and then wound on the periphery of a fixed pin 6 in at least one turn so as to form a closed path 12 around the fixed pin 6.
  • a portion of the yarn 2 entering into the clpsed path and a portion of the yarn 2 emerging from the closed path are entwined with each other in at least one turn.
  • the portion of the yarn 2 emerged from the closed path 12 is delivered by a pair of delivery rollers 8 and then wound up by means ofa driving roller 10 into a take-up package 11 through a guide 9.
  • the yarn 2 travels through a closed path 12 formed around the periphery of the fixed pin 6.
  • a portion 13 of the yarn 2 entering into the closed path 12 and a portion 14 of the yarn 2 emerging from the closed path 12 are entwined with each other.
  • the portion 13 of the yarn 2 is entwined about the portion 14 of the yarn 2 in the S direction, and twisted in the S direction by the forward travel of the portion 14.
  • the heater 5 is disposed upstream of the closed path 12, the yarn twisted in the S direction is heat-set by the heater 5, and cooled between the heater 5 and the pin 6.
  • the portion 16 of the yarn 2 is slightly untwisted in the Z direction by the forward travel of the emerging portion 14 because the entered portion 16 of the yarn 2 immediately contacts the periphery of the fixed pin 6 so as to prevent untwisting of the portion 16.
  • the S twists of the yarn 2 are retained during the advance along the periphery of the fixed pin 6.
  • the yarn 2 passes through the region 7 of the closed path 12 wherein the entering and emerging portions 13 and 14 of the yarn are entwined with each other in at least one turn.
  • the portion 17 of the yarn 2 emerged from the closed path 12 is entirely untwisted in the Z direction by the forward travel of the entering portion 13 of the yarn 2.
  • the portion 13 of the yarn 2 entering into the closed path 12 is twisted in the S direction and the portion 17 of the yarn 2 emerged from the closed path is entirely untwisted in the Z direction.
  • the resultant textured yarn has a high torque in the Z direction.
  • the entering portion 13 and the emerging portion 14 of the yarn 2 are entwined in the Z direction. Accordingly, the entering portion 13 is twisted in the Z direction by the forward travel of the emerging portion 14 and heat-set by the heater as shown in FIG. 1, and the emerged portion 17 is untwisted in the S direction by the forward travel of the entering portion 13.
  • the resultant textured yarn from the method as shown in FIG. 28 has a high torque in the S direction. That is, according to the method of the present invention, the twist direction of the yarn can be easily established by selecting the entwining direction of the entering and emerging portions of the yarn 2.
  • the entering portion 13 and the emerging portion of the yarn 2 are entwined with each other while in contact around the periphery of the fixed pin 6.
  • the entwined portions of the yarn 2 are kept on or near the periphery of the fixed pin 6.
  • the diameter of the fixed pin is not too large. That is, generally, it is preferable that the diameter of the fixed pin is in a range from 0.8 to 3.0 mm. Also, it is necessary that the fixed pin periphery has a low frictional coefficient and a high resistance to rubbing. Accordingly, in general, the fixed pin is made of ruby, sapphire or alumina ceramic.
  • the pin for defining the closed path is fixed in a non-rotatable condition, but, sometimes, it is allowable for the pin to be rotatable.
  • the closed path 12 is defined by the fixed pin 6 and a rotatable guide roller 15.
  • the twist number varies with variation of the cross angle between the emerged portion 17 and the entered portion 16 of the yarn 2, and when the cross angle is 90, the entering portion 13 is twisted at a maximum twist number.
  • the cross angle (1: can be varied by moving the rotatable guide roller along the direction of the arrows indicated in the drawings. That is, comparing FIG. 48 with FIG. 4A, when the guide roller 15 is approached to the emerged portion 17, the cross angle 4) is decreased so as to decrease the twist number.
  • the fixed pin 60 shown in FIG. SA has a diameter smaller than that of the fixed pin 61) shown in FIG. 5B.
  • the cross angle (1) is varied by moving the fixed pin 6 along the direction of the arrow as shown in the drawing.
  • a curve (a) shows the relationship between the twist number and the cross angle 4) when a nylon 66 filament yarn of 20 denier/3 filaments was falsetwisted by entwining in one turn, utilizing the apparatus as shown in FIG. 3 wherein a rotatable guide roller of 15 mm diameter is arranged at a distance of 25 mm from a fixed sapphire pin of 2 mm diameter, at a feed rate of 700 m/min, under a tension of 0.3 g/d.
  • the curve (b) shows the same relationship as that of the curve (a) except that the yarn is entwined in two turns. From the curves (a) and (b), it is clear that the closer the cross angle approaches the more the twist number increases.
  • FIG. 8 shows the relationship between the diameter of the fixed pin and the twist number when a nylon 6 filament yarn of 20 denier/3 filaments is false-twisted at a feed rate of 700 m/min under a tension of 0.3 g/d by utilizing the apparatus as shown in FIG. 1 using several fixed sapphire pins having diameters different from each other. As is clearly shown in FIG. 8, the greater the diameter of the fixed pin, the less the twist number.
  • FIG. 9 shows the relationship between the twist number, denier of yarn and number of filaments in the yarn when nylon 6 filament yarns of denier and numbers of filaments different from each other are false-twisted by means of an apparatus as shown in FIG. 3 using a fixed sapphire pin of 2 mm diameter, and a feed rate of 700 m/min under a tension of 0.2 g/d. From the drawing, it is clear that the greater the denier of the yarn and the greater the number of filaments in the yarn, the less the twist number of the textured yarn false-twisted according to the method and apparatus of the present invention.
  • the textured yarn manufactured by the method and apparatus of the present invention When the textured yarn manufactured by the method and apparatus of the present invention is freely suspended, it rotates in a direction opposite to that of the false-twisting until it reaches a stationary condition or creates snarls, but substantially does not create crimp. Accordingly, the fabric from the textured yarn according to the present invention has a low bulkiness, high stretchability,- smooth appearance and elegant hand feeling.
  • the method and apparatus of the present invention does not require a rotor member rotating at a high velocity such as a spindle and frictional member.
  • the apparatus of the present invention is very simple in its construction and can falst-twist the yarn at a very high velocity, for example, 500 to 2,000 m/min. It is accordingly possible to connect the false-twisting step of the present invention to the spinning and drawing step of the filament yarn so as to continuously carry out spinning, drawing and false-twisting steps. Also, the method and apparatus of the present invention can be carried out at a very low processing cost.
  • Example 1 A nylon 66 filament yarn of 25 denier/3 filaments was false-twisted in the S direction and the Z direction by utilizing an apparatus as shown in FIGS. 1, 2A and 28 using a fixed sapphire pin of 0.8 mm diameter under the following conditions:
  • the snarl index above represents the magnitude of the torque of the textured yarn and is determined in the following manner.
  • a yarn is stressed between a fixed end support and a movable end support such that the length under a tension of 0.1 g/denier is 50 cm.
  • a weight of 50 mg is hung at the center of the yarn.
  • the movable end support is moved toward the fixed end support.
  • the snarl index is determined from the equation:
  • a stocking was knitted from the resultant textured yarns of S and Z torques by alternately feeding them.
  • the resultant stocking had a high stretching property and a soft touch.
  • the resultant textured yarn had numerous crimps and no torque.
  • Example 2 Apolyetlyleneterephthalate filament yarn of 50 de- [tier/l2 filaments was false-twisted in the S and Z directions by means of apparatus the same as that used in Example 1 under the following conditions:
  • a stocking was prepared from the resultant S and Z torque yarns by alternately feeding them.
  • the resultant stocking had a high stretching property and a uniform appearance.
  • Example 4 A nylon 6 mono-filament yarn of 20 denier having an original twist of 14 turns/meter in the S direction was false-twisted in the S direction by the apparatus as shown in FIG. 6 containing a rotatable pin of 15 mm diameter under the following conditions.
  • Twine number I turn The false-twisting was effected at a twist number of 2,100 turns/meter, and the yarn was converted to a torque yarn having a snarl index of 54.5 and no crimp.
  • Example 5 A nylon 6 filament yarn of 20 deniers/3 filaments was false-twisted in the S and Z directions by employing the apparatus shown in FIGS. 3, 4A and 48 comprising a fixed sapphire pin of 2 mm diameter and a rotatable guide roller of 15 mm diameter disposed at a distance of 2.5 cm from the pin center to the roller center under the following condition:
  • the resultant S and Z torque yarns were used for the manufacture of a stocking by alternately feeding them.
  • the resultant stocking had a high stretching property and uniformity and elegant hand feeling.
  • a method of producing a high torque filament yarn comprising the steps of heating a thermoplastic synthetic mono or multifilament yarn at a temperature at which said yarn is plasticized;

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
US00193331A 1970-11-04 1971-10-28 Method for false-twisting a synthetic filament yarn Expired - Lifetime US3791130A (en)

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JP9696670 1970-11-04
JP9696570 1970-11-04

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US (1) US3791130A (enrdf_load_stackoverflow)
CA (1) CA952385A (enrdf_load_stackoverflow)
DE (1) DE2154887A1 (enrdf_load_stackoverflow)
GB (1) GB1374286A (enrdf_load_stackoverflow)
IT (1) IT941075B (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5094068A (en) * 1990-04-09 1992-03-10 Murata Kikai Kabushiki Kaisha False twister for yarn
US5136835A (en) * 1989-02-13 1992-08-11 Murata Kikai Kabushiki Kaisha False twisting method for yarns and false twisting apparatus therefor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3035396A (en) * 1957-08-21 1962-05-22 Patentex Inc Torque low twist yarn and machine and method for producing the same
US3148520A (en) * 1957-08-21 1964-09-15 Patentex Inc Method for simultaneously throwing and knitting of yarn
US3178795A (en) * 1962-10-10 1965-04-20 Deering Milliken Res Corp Method for edge crimping thermoplastic yarns
US3360838A (en) * 1965-10-20 1968-01-02 Alamance Ind Inc Method of forming a non-torque curled yarn

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3035396A (en) * 1957-08-21 1962-05-22 Patentex Inc Torque low twist yarn and machine and method for producing the same
US3148520A (en) * 1957-08-21 1964-09-15 Patentex Inc Method for simultaneously throwing and knitting of yarn
US3178795A (en) * 1962-10-10 1965-04-20 Deering Milliken Res Corp Method for edge crimping thermoplastic yarns
US3360838A (en) * 1965-10-20 1968-01-02 Alamance Ind Inc Method of forming a non-torque curled yarn

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5136835A (en) * 1989-02-13 1992-08-11 Murata Kikai Kabushiki Kaisha False twisting method for yarns and false twisting apparatus therefor
US5094068A (en) * 1990-04-09 1992-03-10 Murata Kikai Kabushiki Kaisha False twister for yarn

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CA952385A (en) 1974-08-06
GB1374286A (en) 1974-11-20
DE2154887A1 (enrdf_load_stackoverflow) 1972-05-18
IT941075B (it) 1973-03-01

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