JP2006183200A - Cellulose ester primarily twisted false-twist textured yarn and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellulose ester primarily twisted false-twist textured yarn expressing a crispy feeling by imparting a fine crepe feeling to a woven or a knitted fabric and having torque and crimps in combination. <P>SOLUTION: The cellulose ester primarily twisted false-twist textured yarn is a primarily twisted false-twist textured yarn composed of a cellulose ester composition consisting essentially of a cellulose ester in which at least a part of hydroxy groups are substituted with 3-18C acyl groups. The twisting direction of the primary twisting and the twisting direction of the false twisting are the same and the number of torque twisting is 100-400 turns/m. The average crimp pitch is 0.3-5 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cellulose ester pre-twisted false twisted yarn suitable for women's clothing and a method for producing the same. More specifically, the present invention relates to a cellulose ester-based pre-twisted false twisted yarn imparted with torque and crimp by a pre-twisted false twist because the composition used in the present invention has thermoplasticity, and a method for producing the same. It is.

  Conventionally, as a raw yarn of a wrinkle woven fabric or a surface effect woven or knitted fabric used for women's clothing, a real-strength high-strength yarn or a pre-twisted false-twisted yarn made of polyester fiber has been used (see Patent Document 1). The yarns of No. 1 did not have satisfactory levels of color developability, gloss and sharpness. Further, the pre-twisted false twisted yarn made of polyester fiber has a problem that untwisting is likely to occur, and worm-eaten defects are generated on the woven or knitted fabric. Furthermore, in the case of these yarns, functionality such as moisture absorption / release properties could not be imparted.

As cellulose filaments, rayon fibers made of viscose or cupra, and cellulose single ester fibers made of cellulose diacetate and cellulose triacetate are known. Since none of these fibers has thermoplasticity, these fibers cannot be fiberized by melt spinning, and are produced by a wet or dry spinning method using a solvent. While these fibers are derived from cellulose, they have very good characteristics as clothing fabrics such as good gloss and moisture absorption and release, while thermoplastic fibers such as polyester fibers due to lack or lack of thermoplasticity. The false twisting process normally performed cannot be performed, that is, the first twisted yarn could not be obtained.
For this reason, on product development, a method has been proposed in which polyester fibers and nylon fibers are mixed and false twisted, and the entire bulkiness is obtained by crimping the polyester fibers and nylon fibers which are mixing partners (Patent Documents). 2). However, even in these methods, there is a problem in that sufficient weaving feeling cannot be imparted to the woven or knitted fabric, and good characteristics such as hygroscopicity and color developability of the cellulose acetate fiber cannot be sufficiently exhibited. was there.
JP 2002-38344 A JP 2000-34633 A

  Therefore, the problem to be solved by the present invention is a cellulose ester pre-twisted false twisted yarn capable of imparting a high-quality sharpness to a woven or knitted fabric, which could not be achieved by the above-described polyester fiber or cellulose acetate fiber. It is in providing the manufacturing method. Another problem to be solved by the present invention is to provide a knitted or knitted fabric having advantages such as moisture absorption / release properties and high color developability inherent to cellulose ester fibers.

The cellulose ester pre-twisted false twisted yarn of the present invention that achieves the above-mentioned object has the following configuration. That is, the cellulose ester-based pre-twisted false twisted yarn of the present invention is a pre-twisted false twist made of a cellulose ester composition mainly composed of a cellulose ester in which at least some of the hydroxyl groups are substituted with acyl groups having 3 to 18 carbon atoms. A twisted yarn, wherein the twisting direction of the first twist and the twisting direction of the false twist are the same direction, the torque twist number is 100 to 400 times / m, and the average crimped pitch is 0.3 to 5 mm. It is the characteristic cellulose ester type pre-twist false twisted yarn.
One preferred embodiment of the cellulose ester-based pre-twisted false twisted yarn of the present invention is selected from the group consisting of cellulose propionate, cellulose butyrate, cellulose acetate propionate and cellulose acetate butyrate. And at least one cellulose ester.
Moreover, one of the preferable aspects of the cellulose-ester-type pre-twist false twisted yarn of this invention is that the said cellulose-ester composition contains 2-25 wt% of water-soluble plasticizers.
Moreover, the woven or knitted fabric of the present invention is characterized in that the cellulose ester-based pre-twist false twisted yarn is used at least in part, and the moisture absorption at 20 ° C. and 65% RH is 1 to 10%. Woven and knitted.
Moreover, the manufacturing method of the cellulose ester pre-twisted false twisted yarn of the present invention that achieves the above-mentioned object is mainly composed of a cellulose ester in which at least a part of the hydroxyl groups are substituted with acyl groups having 3 to 18 carbon atoms. The fiber yarn comprising the cellulose ester composition is subjected to a pre-twist having a pre-twist coefficient K1 of 2000 to 15000 represented by the following formula (1), and then using a contact type or non-contact type heating medium. With a false twisting rotor whose false twisting direction is the same as the pre-twisting direction and the false twisting coefficient K2 represented by the following formula (2) is 5000 to 35000 while heating to a yarn temperature of 80 to 150 ° C. A method for producing a cellulose ester-based pre-twisted false-twisted yarn, wherein false twisting is applied, then untwisted and wound into a package.
K1 = T1 × D− ^{1 / 2} formula (1)
K2 = T2 × D− ^{1 / 2} formula (2)
T1: Number of pre-twist (times / m)
T2: Number of false twists (times / m)
D: Total fineness (dtex)
One of the preferred embodiments of the method for producing a cellulose ester-based pre-twisted false twisted yarn of the present invention is that the cellulose ester composition contains 2 to 25 wt% of a water-soluble plasticizer.

According to the present invention, by applying a pre-twist false twisting process to yarns based on cellulose derivatives that have not been obtained in the past, high-quality, high moisture-absorbing and releasing properties, and touch-sensitive feel of cellulosic fibers, It is possible to impart a physical property of a sharp feeling to the woven or knitted fabric.
In addition, the woven or knitted fabric of the present invention is particularly suitable for women's clothing materials as clothing, but can also be used for Japanese clothing, sports clothing, lining, and the like.

  The pre-twisted false-twisted yarn of the present invention comprises a cellulose ester composition. In the cellulose ester which is the main component of the cellulose ester composition, at least a part of the hydroxyl groups is substituted with an acyl group having 3 to 18 carbon atoms. It is a thing. A pre-twisted false twisted yarn made of cellulose acetate such as cellulose diacetate or cellulose triacetate, which is substituted only with an acetyl group having 2 acyl groups, has almost no thermoplasticity as a polymer composition. It cannot receive a sufficient heat set during processing, and does not have a sufficiently strong crimp and bulkiness. On the other hand, when at least a part of the hydroxyl groups are mainly composed of a cellulose ester substituted with, for example, a propionyl group having 3 carbon atoms, heat setting at the time of false twisting is possible. The false twisted yarn has, for example, a strong crimp that remains even after the hot water treatment.

  With respect to the number of carbon atoms of the acyl group that substitutes at least a part of the hydroxyl groups, if the number of carbon atoms is 3 or more, a pre-twisted false twisted yarn having a strong crimp due to good thermoplasticity. Further, if the number of carbon atoms is 18 or less, the strength and heat resistance of the false twisted yarn are not lowered. Specific examples of the acyl group having 3 or more carbon atoms include propionyl group (propanoyl group), butyryl group (butanoyl group), pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, decanoyl group, tetradecanoyl group Group, hexadecanoyl group, octadecanoyl group and the like. Moreover, the acyl group which substitutes a hydroxyl group does not need to be 1 type, and the cellulose mixed ester substituted by the C2-acetyl group and the C3-propionyl group may be sufficient.

  Examples of specific cellulose esters that can be employed in the present invention include cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate capronate, cellulose acetate caprylate, cellulose Examples include acetate laurate, cellulose acetate palmitate, cellulose acetate stearate, cellulose acetate oleate, cellulose acetate phthalate, and cellulose propionate butyrate. Among them, since it is easy to produce and has excellent heat resistance, in the present invention, at least one selected from the group consisting of cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate. The cellulose ester is particularly preferred.

In addition, the substitution ratio (substitution degree) of the hydroxyl group of cellulose with the acyl group is such that 2.4 to 3.0 hydroxyl groups are substituted with acyl groups out of 3 hydroxyl groups per glucose unit constituting cellulose. It is preferable. The substitution degree of the hydroxyl group is more preferably 2.5 to 2.9, and most preferably 2.6 to 2.8. However, when the cellulose ester is esterified with two or more types of acyl groups, the degree of substitution means the total degree of substitution with all acyl groups.
The cellulose ester in which at least a part of the hydroxyl groups are substituted with an acyl group having 3 to 18 carbon atoms can be synthesized by a known method.

Further, the cellulose ester composition used in the present invention is mainly composed of the above-mentioned cellulose ester, but in addition to the cellulose ester, a cellulose ester composition containing 2 to 25 wt% of a plasticizer is also preferably employed. The
Cellulose ester fibers comprising a cellulose ester composition containing a plasticizer have good heat setability during false twisting, and as a result, a pre-twisted false twisted yarn having a strong crimp is obtained. The plasticizer content is preferably 2 wt% to 25 wt%. If the content is 2 wt% or more, the thermoplasticity and heat setting properties of the entire cellulose ester composition will be good, and if the content is 25 wt% or less, the strength and heat resistance of the pre-twist false twisted yarn will be improved. Does not decrease excessively. In the present invention, the plasticizer content in the cellulose ester composition is more preferably 5 to 20 wt%, and most preferably 10 to 18 wt%.

  Plasticizers play an important role in imparting thermoplasticity to fibers during false twisting, but if they remain in the final product, such as textiles or knitted fabrics, heat resistance decreases and dyeing fastness Undesirable effects such as deterioration. Therefore, the plasticizer in the present invention is preferably water-soluble. Here, water-soluble means that the solubility in room temperature water or heated water is 2 wt% or more.

  Examples of the water-soluble plasticizer that can be specifically used in the present invention include glycerin, polyethylene glycol, poly (ethylene glycol-propylene glycol), polyvinyl pyrrolidone, polyvinyl alcohol, and modified products and copolymers thereof. When polyethylene glycol is used as the water-soluble plasticizer, the molecular weight is preferably 400 to 2000, and most preferably 500 to 1500. In the present invention, the cellulose ester fiber is obtained by heating and melting a cellulose ester composition comprising at least a cellulose ester and a plasticizer in a known melt extrusion spinning machine, then extruding it from a die, spinning it, and drawing it as necessary. It can be manufactured by a winding method. At this time, the spinning temperature is preferably 180 to 260 ° C, more preferably 190 to 250 ° C. By setting the spinning temperature to 180 ° C. or higher, the melt viscosity is lowered and the melt spinnability is improved. Moreover, the thermal decomposition of a cellulose-ester composition is suppressed by making spinning temperature 260 degrees C or less.

  Further, the cross-sectional shape of the cellulose ester fiber comprising the cellulose ester composition used in the present invention may be circular or irregular, but it produces an elegant luster, and is irregular such as a triangle or hexagon. A cross-sectional shape is preferred.

  The single fiber fineness of the cellulose ester fiber is preferably 1 dtex or more from the viewpoint of creating a sharp feeling, and preferably 10 dtex or less from the viewpoint of obtaining a soft texture.

Further, the total fineness of the cellulose ester-based pre-twist false twisted yarn of the present invention comprising cellulose ester fibers is preferably 30 dtex or more and 300 dtex or less from the viewpoint of obtaining a supple texture.

In the cellulose ester pre-twist false twisted yarn of the present invention, it is important that the twist direction of the pre-twist and the twist direction of the false twist are the same direction, and the number of torque twists is 100 to 400 times / m. Since the first twist and false twist are in the same direction and 100 turns / m or more, torque can be applied to the yarn, and the restraint of the woven or knitted fabric is delicately distorted in the torque expression direction, producing delicate wrinkles, High quality sharpness can be imparted to the woven or knitted fabric. The torque twist number is preferably 150 to 250 times / m.
Further, in the case of yarns made of ordinary polyester fibers, if the number of torque twists is 150 times or more, untwisted yarns are often generated in the processed yarn, which deteriorates the surface quality of the woven or knitted fabric. Since the cellulose ester composition used in the present invention is not as thermoplastic as polyester, the surface quality is not a problem as long as the torque twist number is less than 400.

  In addition, the average crimp pitch of the single fibers constituting the cellulose ester-based pre-twisted false-twisted yarn of the present invention is important in that a uniform wrinkle is imparted to the woven or knitted fabric. . Here, the crimp pitch refers to the distance (mm) from a certain peak to the next peak when the crimped form of the first twist false twisted yarn is observed with an optical microscope. When the false twisted yarn is composed of a plurality of single yarns, each single fiber is measured at 10 points, and the average value of all the measurement results is used as the average crimped pitch. If the average crimp pitch is less than 0.3 mm, even if there is torque on the yarn, fine crimps absorb the wrinkles, and it is impossible to obtain a sense of sharpness. On the other hand, when the average crimp pitch is larger than 5 mm, uniform texture cannot be imparted to the woven or knitted fabric, resulting in poor surface quality. The average crimp pitch is more preferably 0.3 mm to 2 mm.

The method for producing a cellulose ester-based pre-twisted false-twisted yarn of the present invention is a fiber yarn comprising a cellulose ester composition containing as a main component a cellulose ester in which at least some of the hydroxyl groups have been substituted with acyl groups having 3 to 18 carbon atoms. The yarn is subjected to a first twist in which the first twist coefficient K1 represented by the following formula (1) is 2500 to 15000, and then the yarn temperature is set to 80 to 150 ° C. using a contact type or non-contact type heating medium. While heating, the false twisting direction is the same as the pre-twisting direction, the false twisting coefficient K2 represented by the following formula (2) is 15000 to 35000, and false twisting is applied by the false twisting rotor. This is a process of winding up on a package.
K1 = T1 × D− ^{1 / 2} formula (1)
K2 = T2 × D− ^{1 / 2} formula (2)
T1: Number of pre-twist (times / m)
T2: Number of false twists (times / m)
D: Fineness (dtex)

In this case, the cellulose ester composition is at least one cellulose ester selected from the group consisting of cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate as the cellulose ester of the main component. Is preferred. The cellulose ester composition can preferably contain 2 to 25 wt% of a water-soluble plasticizer.

  In order to obtain the cellulose ester-based pre-twisted false twisted yarn of the present invention, first, it is necessary to perform a pre-twisted false twist having a pre-twist coefficient K1 of 2500 to 15000. Torque can be imparted to the yarn when the tip twist coefficient is K1> 2500. Moreover, generation | occurrence | production of the brittle in a weaving or a knitting process can be suppressed because a tip twist coefficient is K1 <15000. A more preferable tip twist coefficient is 3000 <K1 <11000.

The cellulose ester composition used in the present invention has a problem that fluff is likely to occur when performing false twisting because the fiber surface has a feature that the fiber surface is easily fibrillated in addition to low elongation. In the present invention, by carrying out the above-mentioned pre-twisting before false twisting, the shear strain to the yarn in false twist can be eased, and the occurrence of fluff can be suppressed.
The direction of the pre-twisting may be either S or Z, and the yarn can be twisted according to a conventional method using a general twisting machine such as an Italy twisting machine, a down twister, or a double twister.

Since the twisted yarn obtained from the pre-twisted yarn has a twisting torque, it is preferably supplied to a false twisting machine through a bobbin cap for anti-billing. That is, when the tension applied to the yarn is lowered, the pre-twisted yarn is likely to generate bills and snares, and these can be prevented by applying an appropriate tension.
FIG. 1 is a process schematic diagram for illustrating the production process of the cellulose ester-based pre-twisted false twisted yarn of the present invention. In FIG. 1, a supply yarn 1 made of cellulose ester fiber is unwound through a bobbin cap A which is a twist prevention device, and is stably supplied to a heating medium C using a feed roller B, and a yarn temperature of 80 Heat to ~ 150 ° C. As the heating medium C, a known medium for false twisting may be appropriately used. Specific examples of the contact heating medium include a hot plate heated by electric heating or a circulating heating medium. Further, as a non-contact type heating medium, a slit heater can be given as a specific example. In any case, it is important that the temperature of the fiber yarn is heated to 80 to 150 ° C. If heating temperature is 80 degreeC or more, a cellulose-ester type fiber can be heat-set in a heating state, a strong crimp can be provided, and a highly bulky processed yarn can be obtained. Moreover, if heating temperature is 150 degrees C or less, a rough feeling does not generate | occur | produce by the melt | fusion of a fiber, and it is a preferable aspect. From the viewpoint of sufficient heat setting properties and prevention of fusion, the temperature of the fiber yarn is preferably 90 to 130 ° C, and most preferably 100 to 120 ° C.

The running yarn heated while being twisted is then cooled by the cooling medium D and passes through a false twist rotor E for giving false twist. The false twisting rotor E may be a spinner pin that gives a direct twisting yarn, or may be a friction disk or a belt nip that gives a twisting yarn indirectly, but a preferred false twisting rotor is a spinner that gives a direct twisting yarn. It is a pin.
At this time, it is important to set the false twist coefficient K2 to 15000 to 35000 from the viewpoint of process passability. When K2 <15000, snare occurs frequently and the weaving and knitting process passability deteriorates. Further, if K2> 35000, yarn breakage during false twisting is likely to occur. A more preferable range of K2 is 20000 to 32000.
The traveling yarn is untwisted after passing through the false twisting rotor E, and is finally wound on the package I. If necessary, entanglement or fiber mixing may be imparted using a nozzle G installed between the stretching roller F and the relaxing roller H. As the nozzle G, a compressed air nozzle typified by an interlace nozzle or a taslan nozzle can be used without particular limitation.
A woven or knitted fabric can be knitted and woven using the cellulose ester-based pre-twisted false twisted yarn of the present invention. When the cellulose ester composition serving as the base used in the present invention is derived from cellulose, it exhibits good characteristics such as moisture absorption / desorption, color developability, and cool contact feeling when used as a cloth for clothing.

The woven or knitted fabric of the present invention uses cellulose ester-based pre-twisted false twisted yarn at least in part, and the form of the woven or knitted fabric is not particularly limited, and may be a woven fabric having an arbitrary structure and yarn configuration.
In addition, if the moisture absorption rate at 20 ° C. and 65% RH is 1 to 10%, the woven or knitted fabric of the present invention has good moisture absorption and release properties, and is very suitable for clothing applications. The moisture absorption rate is preferably 2% or more, and most preferably 4% or more from the viewpoint of the comfort of the woven or knitted fabric.
The cellulose ester-based pre-twisted false-twisted yarn of the present invention is suitable as a base yarn for a wrinkle woven fabric, a surface effect woven or knitted fabric used for women's clothing, and a Japanese wearing scale.

Hereinafter, the cellulose ester-based pre-twisted false twisted yarn of the present invention and the production method thereof will be described in detail with reference to examples. In addition, the physical property in an Example was calculated | required with the following method.
A. Fix both ends of the pre-twisted false twisted yarn sampled to a length of 1m of torque twist in the transverse direction, and gradually bring both ends closer to the center of the processed yarn with a load of 0.5mg / d suspended. The number of twists when both ends coincide is measured as the number of twisted torques per 50 cm, and is calculated per meter.
B. Moisture absorption rate About 1 g of a fiber sample is prepared, and the weight (W0) when completely dried is measured. This sample was left in a thermo-hygrostat (LH-20-11M manufactured by Nagano Scientific Machine) conditioned at 20 ° C. and 65% RH for 24 hours, and the weight (W20) of the sample in an equilibrium state was measured. Measure and obtain by the following formula.
・ Hygroscopic rate (%) = (W20−W0) / W0
C. Color developability Black color developability is obtained by stacking 4 sheets of the obtained woven or knitted fabric and measuring L * 5 times with a colorimeter (SM-3 type manufactured by Suga Test Instruments Co., Ltd.) under the condition of a measurement diameter of 30 mmφ. The average value was evaluated.

D. Texture (sharp feeling) ◎ that feels relatively large in the feeling when holding the fabric of each of the examples and comparative examples is ◎, those that feel large are ○, those that do not feel large are ×, The characteristics were those close to the average of five randomly selected evaluations.

E. Surface quality When the surface of each of the fabrics of Examples and Comparative Examples was observed, the surface quality was very good: ◎, good: ○, bad: ×, slightly bad: △ The characteristics close to the average of human evaluation were used as characteristics.

(Example 1)
A cellulose ester composition containing 80 parts of cellulose acetate propionate (Eastman Chemical Co., Ltd.) (ester substitution degree: 2.7) and 20 parts of polyethylene glycol (PEG 600, Sanyo Chemical Co., Ltd.) as a plasticizer is biaxial. The pellets were obtained by kneading with an extruder. The pellets were vacuum-dried on a shelf dryer under conditions of 80 ° C. × 8 hours to be in an absolutely dry state, and then melt-spun with a melt spinning machine at a spinning temperature of 260 ° C. and a spinning speed of 1000 m / min. , 105 dtex-24f fiber yarn was obtained. Using the obtained fiber yarn as a supply yarn, first, a pre-twist having a pre-twist coefficient (K1) of 4000 in the S direction is performed with a down twister made by Ishikawa Seisakusho, and then IVF-24 made by Ishikawa Seisakusho Co., Ltd. Using a false twisting machine, false twisting was performed under the conditions of a spinner pin of 1 mmφ, a hot plate temperature of 120 ° C., a false twisting coefficient (K2) of 26000, a stretch rate of 1.1, and a working speed of 100 m / min. The temperature of the fiber yarn contacted by the hot plate was 120 ° C. The number of torque twists of the obtained pre-twist false twisted yarn was 195 times / m, and the average crimped pitch was 0.9 mm. Using the obtained pre-twisted false twisted yarn for warp and weft, a plain fabric was prepared with a rapier loom, and then heat treated for 10 minutes in boiling water. The obtained woven fabric expressed fine wrinkles, had a very sharp feel, and had good surface quality. Further, both hygroscopicity and color development were good. The results are shown in Table 1.

(Example 2)
In the same manner as in Example 1 except that the same fiber yarn as in Example 1 was used as the supply yarn, and the pre-twist coefficient (K1) was changed to 2800 and the false twist coefficient (K2) was changed to 30000. Twisting was performed. The obtained twisted false twisted yarn had a torque twist number of 125 times / m and an average crimp pitch of 0.7 mm. As a result of producing a woven fabric by the same method as in Example 1 using the obtained pre-twisted false twisted yarn, the obtained woven fabric had a sharp feeling and a good surface quality. Moreover, both hygroscopicity and color development were good. The results are shown in Table 1.
(Example 3)
Other than using a cellulose ester composition containing 90 parts of cellulose acetate butyrate (Eastman Chemical Co., Ltd.) (degree of ester substitution: 2.7) and 10 parts of polyethylene glycol (PEG 600, Sanyo Chemical Co., Ltd.) as a plasticizer In the same manner as in Example 1, pre-twist false twisting was performed.
The obtained twisted false twisted yarn had a torque twist number of 115 turns / m and an average crimp pitch of 0.8 mm. As a result of producing a woven fabric by the same method as in Example 1 using the obtained pre-twisted false twisted yarn, the obtained woven fabric had a sharp feeling and a good surface quality. Moreover, both hygroscopicity and color development were good. The results are shown in Table 1.

(Comparative Example 1)
Pre-twist false twisting was performed in the same manner as in Example 1 except that cellulose diacetate filament fiber yarn (110 dtex-20f) was used as the supply yarn. The obtained pre-twist false-twisted yarn had a torque twist number of 280 times / m, an average crimp pitch of 19 mm, and could hardly impart crimp. As a result of producing a woven fabric by the same method as in Example 1 using the obtained pre-twist false-twisted yarn, the obtained woven fabric has good hygroscopicity and color developability, but has almost no crimps. Because it is a strip, it was a woven fabric with a hard texture. In addition, since the torque cannot be absorbed by crimping, there is a problem that warp frequently occurs in the warp yarn in the preparation process of weaving. The results are shown in Table 1.

(Comparative Example 2)
False twisting was performed in the same manner as in Example 1 except that the pre-twisting was not performed before the false twisting. The obtained false twisted yarn had a torque twist number of 65 times / m, an average crimp pitch of 7 mm, and could hardly impart torque. In addition, there were many places where single yarn breakage occurred, and fluff was generated. As a result of creating a woven fabric by the same method as in Example 1 using the obtained false twisted yarn, the obtained woven fabric is a fiber yarn having good moisture absorption and color development, but having almost no torque. For this reason, the texture cannot be imparted to the woven fabric, and the sharpness cannot be obtained. The results are shown in Table 1.

(Comparative Example 3)
Using a polyethylene terephthalate fiber yarn (110 dtex-24f) as the supply yarn, a pre-twist false twisting process was performed in the same manner as in Example 1 except that the false twist temperature was 210 ° C. The obtained twisted false twisted yarn had a torque twist number of 210 turns / m, an average crimped pitch of 0.8 mm, and many untwisted yarns. As a result of creating a woven fabric by the same method as in Example 1 using the obtained pre-twist false-twisted yarn, it was possible to impart a grainy feeling to the obtained woven fabric, There were many worm-eating defects on the surface, and the texture was rough. Further, both the hygroscopicity and the color developability were not satisfactory levels. The results are shown in Table 1.

The cellulose ester-based pre-twisted false-twisted yarn of the present invention is particularly suitable for use in women's clothing, and is useful as a raw yarn for grain fabrics and surface effect woven or knitted fabrics used in women's clothing.

FIG. 1 is a process schematic diagram for illustrating the production process of the cellulose ester-based pre-twist false-twisted yarn of the present invention.

Explanation of symbols

1. Supply yarn A. Bobbin cap B. Feed roller C.I. Heating medium D. Cooling medium E. False twisting rotor Stretching roller G. Nozzle H. Relax roller package

Claims (6)

  A pre-twisted false twisted yarn comprising a cellulose ester composition comprising as a main component a cellulose ester in which at least a part of hydroxyl groups are substituted with an acyl group having 3 to 18 carbon atoms, A cellulose ester-based pre-twisted false-twisted yarn characterized in that the twisting direction is the same direction, the number of torque twists is 100 to 400 times / m, and the average crimped pitch is 0.3 to 5 mm.   The cellulose ester according to claim 1, wherein the cellulose ester is at least one cellulose ester selected from the group consisting of cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate. Pre-twisted false twisted yarn.   The cellulose ester pre-twisted false twisted yarn according to claim 1 or 2, wherein the cellulose ester composition contains 2 to 25 wt% of a water-soluble plasticizer.   The cellulose ester-based pre-twisted false twisted yarn according to any one of claims 1 to 3 is used at least in part, and the moisture absorption at 20 ° C and 65% RH is 1 to 10%. Woven knitting. A fiber yarn composed of a cellulose ester composition containing as a main component a cellulose ester in which at least a part of the hydroxyl groups are substituted with an acyl group having 3 to 18 carbon atoms is used as a first twist coefficient K1 represented by the following formula (1). Is subjected to a pre-twist of 2000 to 15000, and then heated to a yarn temperature of 80 to 150 ° C. using a contact-type or non-contact-type heating medium, and the false twist direction is set to the same direction as the pre-twist direction. A cellulose ester-based pre-twisted false-twisted yarn, characterized in that false twist is imparted and untwisted by a false-twist rotor having a false twist coefficient K2 represented by the following formula (2) of 5000 to 35000. Production method.
K1 = T1 × D− ^{1 / 2} formula (1)
K2 = T2 × D− ^{1 / 2} formula (2)
T1: Number of pre-twist (times / m)
T2: Number of false twists (times / m)
D: Total fineness (dtex)   The method for producing a cellulose ester-based pre-twisted false-twisted yarn according to claim 5, wherein the cellulose ester composition contains 2 to 25 wt% of a water-soluble plasticizer.

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