JP2024082716A - Polytrimethylene terephthalate composite yarn, its manufacturing method, and fabric - Google Patents

Abstract

[Problem] To provide a polytrimethylene terephthalate composite yarn that has little yarn breakage during the manufacturing process and has high crimp performance despite its small single fiber fineness, and a manufacturing method and fabric thereof. [Solution] A polytrimethylene terephthalate composite yarn is made by mixing a false twisted crimped yarn made of polytrimethylene terephthalate consisting of 90 mol % or more of trimethylene terephthalate repeat units and having torque in the S direction, and a false twisted crimped yarn made of polytrimethylene terephthalate consisting of 90 mol % or more of trimethylene terephthalate repeat units and having torque in the Z direction, and is characterized in that it simultaneously satisfies the following requirements (1) to (4): (1) Single fiber fineness: 0.3 to 3.2 dtex (2) Breaking strength ≧ 2.5 cN/dtex (3) Crimp rate ≧ 10% (4) Residual torque ≦ 30 T/m [Selected Figure] Figure 1

Description

The present invention relates to a polytrimethylene terephthalate composite yarn that has low yarn breakage during the manufacturing process and high shrink performance despite its small single fiber fineness, as well as a manufacturing method and fabric thereof.

Polytrimethylene terephthalate (hereafter abbreviated as "PTT"), obtained by polycondensation of lower alcohol esters of terephthalic acid, such as terephthalic acid or dimethyl terephthalate, with trimethylene glycol (1,3-propanediol), is a revolutionary polymer in that fibers made from it have properties similar to polyamide, such as a low elastic modulus (soft feel), excellent elastic recovery, and easy dyeability, and performance similar to polyethylene terephthalate (hereafter abbreviated as "PET") fibers, such as light resistance, heat setting properties, dimensional stability, and low water absorption. Taking advantage of these characteristics, it is widely used in sports and fashion fabrics, as well as BCF carpets, brushes, tennis strings, etc.

One fiber form that can make the most of the above-mentioned properties of PTT fiber is false-twisted crimped yarn (sometimes called "false-twisted yarn"). False-twisted yarn made of PTT fiber has excellent elastic recovery and softness compared to fibers with a similar structure to PTT, such as polyester fibers such as PET fiber, making it an extremely excellent raw yarn for stretch fabrics.

However, although false-twist textured yarns using the above-mentioned PTT fibers have excellent elastic recovery and softness, they are prone to yarn breakage, especially when false-twist crimping (sometimes called "false-twist processing") is attempted on PTT fibers with small single fiber fineness, and therefore it is not possible to sufficiently improve the crimping performance.

In addition, the raw yarn used for false twist crimp processing is generally a drawn yarn produced through spinning and drawing processes, which makes it difficult to increase productivity and increases the cost of fiber production. In addition, because it is a drawn yarn, it cannot be subjected to highly productive high-speed false twist crimp processing (so-called POY-DTY processing).

To overcome these shortcomings, a method of false twisting and crimping using partially oriented PTT fibers (hereafter abbreviated as "PTT-POY") produced in a single process, similar to that of PET fibers, is considered. Technology related to this PTT-POY is disclosed in "Chemical Fibers International," Vol. 47, published in February 1997, pp. 72-74 (Non-Patent Document 1), which discloses fibers in which a polymer is extruded and cooled to solidify, a finishing agent is applied, and the fibers are wound at 3-6000 m/min without using a godet roll or after passing through a cold godet roll.

JP 11-229276 A (Patent Document 1) discloses PTT-POY that has been given a specific finishing agent and wound up at 3,300 m/min, with a birefringence of 0.059 and an elongation of 71%, while WO 1999/39041 (Patent Document 2) discloses PTT-POY that has been given a specific finishing agent and wound up at 3,500 m/min, with a birefringence of 0.062 and an elongation of 74%.

However, according to the inventors' investigations, in the case of PTT-POY disclosed in the above non-patent and patent documents, the yarn shrinks significantly on the yarn tube around which the fiber is wound, tightening the yarn tube, causing the yarn tube to deform and making it impossible to remove the cheese-like package from the spindle of the winding machine. Even if a stronger yarn tube is used to prevent such deformation, a phenomenon called bulging, in which the sides of the package expand, can occur, or the yarn can be tightly tightened in the inner layer of the cheese. This increases the tension when the yarn is unwound from the cheese-like package, and also increases tension fluctuations, resulting in frequent fuzzing and yarn breakage during stretch false twist crimp processing, as well as uneven shrinkage and dyeing.

To solve these problems, JP 2001-254226 A (Patent Document 3) studies applying heat before winding to reduce distortion. Also, JP 2015-7306 A (Patent Document 4) studies partially oriented yarn at a spinning speed lower than 2500 m/min. Furthermore, JP 2001-348729 A (Patent Document 5) shows that the peak temperature and peak value of thermal stress are controlled within a specific range by taking up the yarn at a spinning speed of 4500 to 8000 m/min.

However, even if one were to try to make false-twisted, crimped yarn using the above-mentioned partially oriented yarn, the partially oriented yarn using PTT had low false-twist tension and was prone to yarn breakage, and the draw ratio could not be increased, making it difficult to obtain false-twisted, crimped yarn with high crimping performance.

Japanese Patent Application Laid-Open No. 11-229276 International Publication No. 1999/39041 JP 2001-254226 A JP 2015-7306 A JP 2001-348729 A

Chemical Fibers International, Vol. 47, February 1997, pp. 72-74

The present invention has been made in view of the above background, and its purpose is to provide a polytrimethylene terephthalate composite yarn that has low yarn breakage during the manufacturing process and high crimping performance despite its small single fiber fineness, as well as a manufacturing method and fabric thereof.

The inventors conducted intensive research to solve the above problems, and as a result, completed the present invention. Thus, the following invention is provided.

1. A polytrimethylene terephthalate composite yarn, which is made by mixing a false twisted crimped yarn composed of polytrimethylene terephthalate having 90 mol % or more of trimethylene terephthalate repeating units and having torque in the S direction, and a false twisted crimped yarn composed of polytrimethylene terephthalate having 90 mol % or more of trimethylene terephthalate repeating units and having torque in the Z direction, and which simultaneously satisfies the following requirements (1) to (4):
(1) Single fiber fineness: 0.3 to 3.2 dtex
(2) Breaking strength ≧ 2.5 cN/dtex
(3) Shrinkage rate ≧10%
(4) Residual torque ≦ 30 T/m
2. The polytrimethylene terephthalate composite yarn according to the above item 1, having a total fineness of 10 to 400 dtex.
3. The polytrimethylene terephthalate composite yarn according to 1 or 2 above, which is subjected to an interlace processing.
4. The polytrimethylene terephthalate composite yarn according to any one of 1 to 3 above, comprising modified cross-section fibers having a degree of modification of 1.15 to 10.0.
5. The polytrimethylene terephthalate composite yarn according to any one of 1 to 4 above, comprising flat cross-section fibers having a flatness of 2.0 to 10.0.
6. A method for producing a polytrimethylene terephthalate composite yarn as described in 1 above, in which the false twisted crimp textured yarn having a torque in the S direction and the false twisted crimp textured yarn having a torque in the Z direction are produced by draw-false-twisting a polytrimethylene terephthalate fiber that simultaneously satisfies the following requirements (A) to (C):
(A) In the temperature-thermal stress curve of the fiber, there is a maximum value of thermal stress in the temperature range of 40 to 100°C.
(B) The maximum value of the thermal stress of (A) is 0.1 to 0.8 cN/dtex.
(C) The lowest elastic modulus at an elongation of 10 to 30% is 0.1 to 2 cN/dtex.
7. A fabric comprising the polytrimethylene terephthalate composite yarn described in any one of 1 to 5 above.

The present invention provides a polytrimethylene terephthalate composite yarn that has low yarn breakage during the manufacturing process and high shrink performance despite its small single fiber fineness, as well as a manufacturing method and fabric thereof.

FIG. 2 is a schematic diagram for explaining the maximum value of thermal stress in a temperature-thermal stress curve of a fiber. FIG. 2 is a schematic diagram for explaining a method for measuring the lowest elastic modulus at an elongation of 10 to 30%. 1A to 1C are schematic diagrams showing examples of modified cross-sectional yarn shapes and modified degrees. 1A to 1C are schematic diagrams showing examples of flat cross-sectional yarn shapes and irregularities.

The present invention will be described in detail below.
(1) Polymer Raw Material The polymer used in the present invention is polytrimethylene terephthalate (PTT) composed of 90 mol % or more of trimethylene terephthalate repeating units. Here, PTT is a polyester containing terephthalic acid as the acid component and trimethylene glycol (also called 1,3-propanediol) as the diol component. The PTT may contain 10 mol % or less of other copolymerization components.

Such copolymerization components include ester-forming monomers such as 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 3,5-dicarboxylic acid benzenesulfonic acid tetrabutylphosphonium salt, 3,5-dicarboxylic acid benzenesulfonic acid tributylmethylphosphonium salt, 1,4-butanediol, neopentyl glycol, 1,6-hexamethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, adipic acid, dodecanedioic acid, and 1,4-cyclohexanedicarboxylic acid.

If necessary, various additives such as matting agents, heat stabilizers, defoamers, color-matching agents, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, crystal nucleating agents, and fluorescent whitening agents may be copolymerized or mixed.

The intrinsic viscosity [η] of the polymer used in the present invention is preferably 0.7 to 1.5, and more preferably 0.75 to 1.2. Fibers with excellent strength and spinnability can be obtained within this range. If the intrinsic viscosity is less than 0.7, the molecular weight of the polymer is too low, making it more likely that yarn breakage or fuzz will occur during spinning or processing, and it will be difficult to achieve the strength required for false twist and crimp processed yarn. Conversely, if the intrinsic viscosity exceeds 1.5, the melt viscosity will be too high, causing melt fracture and spinning defects during spinning, which is not preferable. The intrinsic viscosity [η] is a measured value, which will be described later in the section on embodiments of the invention.

The polymer used in the present invention can be produced by a known method. That is, terephthalic acid or dimethyl terephthalate and trimethylene glycol are used as raw materials, and one or more metal salts such as titanium tetrabutoxide, calcium acetate, magnesium acetate, cobalt acetate, manganese acetate, or a mixture of titanium dioxide and silicon dioxide are added and reacted under normal pressure or pressure, and then a catalyst such as titanium tetrabutoxide or antimony acetate is added and reacted under reduced pressure at 250 to 270°C. It is preferable to add a stabilizer at any stage of polymerization, preferably before the polycondensation reaction, in order to improve whiteness, improve melt stability, and control the generation of organic substances with a molecular weight of 300 or less, such as PTT oligomers, acrolein, and allyl alcohol. In this case, pentavalent and/or trivalent phosphorus compounds and hindered phenol compounds are preferable as stabilizers.

The polytrimethylene terephthalate composite yarn of the present invention is a polytrimethylene terephthalate composite yarn which is obtained by mixing a false twisted crimp textured yarn composed of polytrimethylene terephthalate having 90 mol % or more of trimethylene terephthalate repeating units and having torque in the S direction, and a false twisted crimp textured yarn composed of polytrimethylene terephthalate having 90 mol % or more of trimethylene terephthalate repeating units and having torque in the Z direction, and which is characterized in that it simultaneously satisfies the following requirements (1) to (4):
(1) Single fiber fineness: 0.3 to 3.2 dtex
(2) Breaking strength ≧ 2.5 cN/dtex
(3) Shrinkage rate ≧10%
(4) Residual torque ≦ 30 T/m

The single fiber fineness of the polytrimethylene terephthalate composite yarn of the present invention must be 0.3 to 3.2 dtex, preferably 0.5 to 3.0 dtex, and more preferably 0.6 to 2.4 dtex. If the single fiber fineness is greater than 3.2 dtex, the single fiber will be too thick and the fabric will lose its softness. If the single fiber fineness is less than 0.3 dtex, thread breakage will occur frequently and it may not be possible to produce the fiber.

The breaking strength of the polytrimethylene terephthalate composite yarn of the present invention must be 2.5 cN/dtex or more, and is preferably 2.7 to 4.5 cN/dtex. If the breaking strength is less than 2.5 cN/dtex, it may not be able to withstand practical use.

The breaking elongation of the polytrimethylene terephthalate composite yarn of the present invention is preferably 20 to 80%. If the breaking elongation is less than 20%, the elongation is too low, and fuzzing or yarn breakage may occur easily during spinning or false twist crimp processing. On the other hand, if the breaking elongation exceeds 80%, the plastic deformation of the fiber may become too large, and shape stability may be deteriorated.

In addition, the fineness variation value U% (normal%) of the polytrimethylene terephthalate composite yarn of the present invention is preferably 2.0% or less. If the fineness variation value U% (normal%) exceeds 2.0%, there is a risk that fuzz and yarn breakage will occur frequently during false twist and crimp processing, resulting in a false twist and crimp processed yarn with large uneven dyeing and shrinkage. It is preferable that U% is 1.5% or less. Of course, the lower the U%, the better.

The fineness variation value U% (normal%) is a value determined from the variation in mass of a fiber sample using a Worcester tester UT-5 manufactured by Zellweger Worcester Co., Ltd. This device can measure the variation in mass by the change in dielectric constant when a fiber sample is passed between electrodes. When the sample is passed through the device at a constant speed, an unevenness curve is obtained. From this result, the fineness variation value U% (normal%) can be determined.

The polytrimethylene terephthalate composite yarn of the present invention must have a crimp rate of 10% or more (more preferably 15 to 40%). If the crimp rate is less than 10%, the elongation is too low and sufficient stretchability cannot be obtained, which is not preferable.

The residual torque of the polytrimethylene terephthalate composite yarn of the present invention must be 30 T/m or less (preferably 0 to 10 T/m). If the residual torque exceeds 30 T/m, the unwinding and handling properties will be poor, which is undesirable.

The total fineness of the polytrimethylene terephthalate composite yarn of the present invention is preferably 10 to 400 dtex, and more preferably 100 to 200 dtex. If the total fineness is less than 10 dtex, the total fineness is too fine, and false twist crimp processing may become difficult. On the other hand, if the total fineness is more than 400 dtex, the fabric loses its softness, which is not preferable. The number of single fibers (filaments) is preferably 40 to 400 (more preferably 40 to 200).

It is also preferable that the polytrimethylene terephthalate composite yarn of the present invention is interlaced. In this case, it is preferable that the number of interlaces is 30 to 90 per meter. If the number exceeds 90, the stretchability may be impaired. Conversely, if the number is less than 30 per meter, the bundling property may be insufficient, and the productivity of woven and knitted fabrics may be impaired.

Furthermore, the polytrimethylene terephthalate composite yarn of the present invention can be composed of fibers with irregular cross sections, such as cross-shaped, triangular, or star-shaped cross sections, which is preferable because it can provide a unique texture. The irregularity of the irregular cross section fiber is calculated by measuring the maximum inscribed circle diameter r and the minimum circumscribed circle diameter R of the fiber cross section, as shown in Figure 3, and the irregularity value R/r is preferably 1.15 to 10.0, and more preferably 1.2 to 10.0, in the present invention. If the irregularity is less than 1.15, the difference from the round cross section may be small. If the irregularity exceeds 10.0, the orientation difference between the outside and inside of the yarn cross section shape during spinning becomes large, and the obtained yarn may have a lot of fluff and slack, making it unsuitable for processing.

The polytrimethylene terephthalate composite yarn of the present invention can also be composed of flat cross-section fibers, which is preferable because it can provide a unique texture. The flatness of the flat cross-section fiber is calculated by drawing a rectangle circumscribing the fiber cross-section, measuring its long side L and short side H, as shown in Figure 4, and calculating the flatness = L/H. In the present invention, the flatness = L/H value is preferably 2.0 to 10.0. If the flatness is less than 2.0, the difference from a round cross-section may be small. If the flatness exceeds 10.0, fluff may be easily generated during spinning, resulting in poor stability.

(2) Manufacturing Method of Polytrimethylene terephthalate Composite Yarn The manufacturing method of polytrimethylene terephthalate composite yarn of the present invention is a method of blending a false twisted crimp textured yarn having a torque in the S direction obtained by draw-false-twisting a polytrimethylene terephthalate fiber that simultaneously satisfies the following requirements (A) to (C), and a false twisted crimp textured yarn having a torque in the Z direction obtained by draw-false-twisting a polytrimethylene terephthalate fiber that simultaneously satisfies the following requirements (A) to (C) with only the false twist direction changed:
(A) In the temperature-thermal stress curve of the fiber, there is a maximum value of thermal stress in the temperature range of 40 to 100°C.
(B) The maximum value of the thermal stress of (A) is 0.1 to 0.8 cN/dtex.
(C) The lowest elastic modulus at an elongation of 10 to 30% is 0.1 to 2 cN/dtex.

First, the polytrimethylene terephthalate fiber for producing the polytrimethylene terephthalate composite yarn of the present invention must have a maximum value of thermal stress in the temperature range of 40 to 100°C on the temperature-thermal stress curve of the fiber. Here, the maximum value of thermal stress refers to the value of thermal stress that corresponds to the point where the differential coefficient of the temperature-thermal stress curve changes from positive to negative when the temperature-thermal stress curve of the fiber is drawn as shown in Figure 1.

If the maximum value of the thermal stress is only in the range below 40°C, the fiber may shrink significantly after winding, resulting in tight winding. If the maximum value of the thermal stress is higher than 100°C, the degree of crystallinity may be too high, and even if it is a composite yarn (a blended yarn of false twisted and crimped yarn), the soft stretchability derived from polytrimethylene terephthalate fiber may not be obtained. The preferred range in which the maximum value of the thermal stress exists is above 50°C and below 100°C.

As mentioned above, the maximum value of the thermal stress exists in the temperature range of 40 to 100°C, so long as it exists in another location, for example, in a range above 100°C. In this case, the maximum value of the thermal stress existing in the range above 100°C may be larger or smaller than the maximum value of the thermal stress existing in the temperature range of 40 to 100°C.

The maximum value of the thermal stress must be 0.1 to 0.8 cN/dtex. If the maximum value of the thermal stress is less than 0.1 cN/dtex, the tension during false twist shrink processing will be lowered, and there is a risk of the shrinkage becoming smaller. On the other hand, if the maximum value of the thermal stress is greater than 0.8 cN/dtex, the tension during false twist shrink processing will be too high, which may cause yarn breakage or loss of softness. A more preferable range for the maximum value of the thermal stress is 0.13 to 0.5 cN/dtex.

Furthermore, the lowest modulus of elasticity of polytrimethylene terephthalate fiber at an elongation of 10 to 30% must be 0.1 to 2 cN/dtex. If the lowest modulus of elasticity at an elongation of 10 to 30% is less than 0.1 cN/dtex, the tension during false twist shrink processing will be lowered, resulting in smaller shrinkage, or the tension will be unstable during yarn processing, which may cause dyeing spots. On the other hand, if the modulus of elasticity is greater than 2 cN/dtex, the tension during false twist shrink processing will be greater, which may cause yarn breakage or loss of softness.

Such polytrimethylene terephthalate fibers are obtained by winding up the melted and solidified polytrimethylene terephthalate yarn at a winding speed of 1000 m/min or more, heating it with a heating roller at the glass transition point of polytrimethylene terephthalate ±20°C, stretching it 0.90 to 3.0 times, winding it around a heating roller at 70 to 150°C, and winding it up at a speed of 2200 to 4000 m/min. If the winding speed of the melted and solidified polytrimethylene terephthalate yarn is less than 2200 m/min, the orientation of the fibers is low, so that if the fibers are stored at around room temperature, the fibers become brittle, making handling of the fibers and stretch-twist-crinkling processing difficult.

On the other hand, if the winding speed of the melted and solidified polytrimethylene terephthalate fiber exceeds 4000 m/min, the elongation becomes too low, making it more likely for fuzz and yarn breakage to occur during spinning and false twist crimp processing.

The false twisted crimped yarn can be produced, for example, by the following method. That is, the polytrimethylene terephthalate fiber may be twisted by a twisting device through a first roller and a heat treatment heater having a set temperature of 90 to 220°C (more preferably 100 to 190°C) to obtain a one-heater false twisted crimped yarn, or may be further introduced into a second heater region and subjected to a relaxation heat treatment, as necessary, to obtain a second-heater false twisted crimped yarn. The draw ratio during false twisting is preferably in the range of 0.8 to 1.5, and the false twist number is preferably α=0.5 to 1.5 in the formula false twist number (T/m)=(32500/(Dtex) ^1/2 )×α, and is usually about 0.8 to 1.2. Here, Dtex is the total fineness of the yarn. The twisting device used is preferably a friction type twisting device of disk type or belt type, which is easy to thread and has little yarn breakage, but a pin type twisting device may also be used. In this case, the torque of the false twisted crimped yarn can be selected to be in the S direction or the Z direction depending on the direction of twisting. Next, the composite yarn is obtained by doubling (mixing) two or more types of false twisted crimped yarns.

Even if the polytrimethylene terephthalate composite yarn of the present invention thus obtained has a single fiber fineness of 0.3 to 3.2 dtex, the thermal stress generated during the production of the false twisted crimped yarn results in a high elastic modulus during the process of stretching the crimp of the false twisted crimped yarn, resulting in a false twisted crimped yarn with a high maximum crimp stress, excellent stretch back properties, and a low torque, which allows for good unwinding properties and easy handling.

Next, the polytrimethylene terephthalate composite yarn is used to knit or weave a fabric, which is then appropriately dyed or sweat-absorbing.
Here, the fabric may be made of only the polytrimethylene terephthalate composite yarn, or may be made of the polytrimethylene terephthalate composite yarn and other yarns. In this case, the other yarns are not particularly limited and may be any of non-crimped yarns, false twisted crimped yarns, latent crimped yarns, spun yarns, etc.

The structure of the fabric is not particularly limited, and may be either knitted or woven. Examples include knitted fabrics with knitting structures such as plain weave, knit miss, smooth, rib, pique, plaited knit, denby, and half, and woven fabrics with weaving structures such as plain weave, twill, and satin, but are not limited to these. The number of layers may be a single layer or multiple layers of two or more layers.

The fabric may then be used to produce textile products such as sportswear, outerwear, innerwear, men's clothing, women's clothing, nursing clothing, work clothes, car seat covering materials, and bedding.
Since such textile products use the above-mentioned fabric, they have a soft feel and excellent stretchability.

Next, examples and comparative examples of the present invention will be described in detail, but the present invention is not limited to these. The measurement items in the examples were measured by the following methods.

(1) Intrinsic viscosity [η]
The intrinsic viscosity [η] was calculated using an Ostwald viscometer by extrapolating the ratio η/C of the specific viscosity η in o-chlorophenol at 35° C. to the concentration C (g/100 milliliters) to a concentration of zero, according to the following formula (1).
[η] = limC → 0 (η / C) ... (1)

(2) Temperature at which the maximum value of thermal stress exists and the maximum value of thermal stress A KE-2 manufactured by Kanebo Engineering Co., Ltd. was used. Measurements were performed with an initial load of 0.044 cN/dtex and a heating rate of 100°C/min. The obtained data was plotted with temperature on the horizontal axis and thermal stress on the vertical axis to draw a temperature-thermal stress curve. The temperature and thermal stress at the point where the differential coefficient of the temperature-thermal stress curve changed from positive to negative were determined, and the stress was divided by the fineness to determine the maximum stress.

(3) Lowest elastic modulus at elongation of 10 to 30% Based on JIS-L-1013, measurements were made at a grip distance of 20 cm and a tensile speed of 20 cm/min using a constant-speed extension tensile tester, Tensilon, manufactured by Orientec Co., Ltd. The smallest slope of the tangent to the SS curve at elongation of 10 to 30% was determined as the elasticity.

(4) Fineness The fineness of the multifilament yarn was measured in accordance with JIS-L-1013. The measured value was divided by the number of single fibers in the multifilament yarn to determine the single fiber fineness.

(5) Breaking strength and breaking elongation: Based on JIS-L-1013, measurements were made using a constant speed extension tensile tester, Tensilon manufactured by Orientec Co., Ltd., at a gripping distance of 20 cm and a pulling speed of 20 cm/min.

(6) Fineness fluctuation value U%
The measurement was carried out using a Worcester Tester UT-5 manufactured by Zellweger Worcester, in the following manner.
Measurement conditions Mode: Normal mode Yarn speed: 200 m/min Twist number: 10,000 times/min S Twist tension range: 10
Measured fiber length: 2000m
Yarn feeding speed: 400 m/min. Measured yarn length: 2000 m.

(7) Shrinkage The test yarn was wound around a measuring machine with a circumference of 1.125 m to prepare a skein with a dry fineness of 3333 dtex. The skein was hung on a hanging nail of a scale plate, and an initial load of 6 g was applied to the lower part of the skein, and the length L0 of the skein was measured when a load of 600 g was further applied. Thereafter, the load was immediately removed from the skein, the skein was removed from the hanging nail of the scale plate, and the skein was immersed in boiling water for 30 minutes to cause shrinkage. The skein after the boiling water treatment was removed from the boiling water, the moisture contained in the skein was absorbed and removed by filter paper, and the skein was air-dried at room temperature for 24 hours. The air-dried skein was hung on a hanging nail of a scale plate, and a load of 600 g was applied to the lower part of the skein, and the length L1a of the skein was measured after 1 minute, and then the load was removed from the skein, and the length L2a of the skein was measured after 1 minute. The crimp percentage (CP) of the test filament yarn was calculated using the following formula.
CP(%)=((L1a-L2a)/L0)×100

(8) Residual torque A sample (crimped yarn) of about 70 cm was stretched weft and an initial load of 0.18 mNx tex (2 mg/dtex) was hung from the center, and the yarn with both ends aligned began to rotate due to the residual torque, but was left in that state until the initial load stopped, to obtain a twisted yarn. The twisted yarn thus obtained was measured for the number of twists over a 25 cm length under a load of 17.64 mNx tex (0.2 g/dtex) using a twist detector, and the obtained twist number (T/25 cm) was multiplied by 4 to obtain the residual torque (T/m).

(9) Number of entanglements The interlaced yarn was cut to a length of 1 m under a load of 8.82 mNx (0.1 g/dtex), and the load was gradually increased. After letting the yarn shrink for 24 hours at room temperature, the number of knots was read and expressed in units per meter.

[Example 1]
Dimethyl terephthalate and 1,3-propanediol were charged in a molar ratio of 1:2, and titanium tetrabutoxide equivalent to 0.1% by weight of dimethyl terephthalate was added, and the transesterification reaction was completed under normal pressure at a heater temperature of 240° C. Next, 0.1% by weight of the theoretical polymer amount of titanium tetrabutoxide and 0.5% by weight of the theoretical polymer amount of titanium dioxide were further added, and the reaction was carried out at 270° C. for 3 hours. The obtained polymer was composed of 100 mol % trimethylene terephthalate repeating units, and had an intrinsic viscosity of 1.0.

The resulting polymer was dried in a conventional manner to reduce the moisture content to 50 ppm, then melted at 265° C. and extruded through a single-arranged spinneret having 24 holes with a diameter of 0.27 mm.
The extruded molten multifilament was quenched by blowing air at a speed of 2.0 m/min to convert it into a solid multifilament, and then an oil agent containing 60% by weight of octyl stearate, 15% by weight of polyoxyethylene alkyl ether, and 3% by weight of potassium phosphate was applied to the fiber using a guide nozzle so that the amount of oil applied to the fiber was 0.6% by weight together with a water emulsion finishing agent having a concentration of 10% by weight.

Next, the solid multifilament was wound around a roll heated to 50°C and having a peripheral speed of 2300 m/min, and then wound around a roll heated to 80°C so as to be stretched at 1.2 times, and then wound at a winding speed of 2700 m/min using a winding machine that drives both the spindle and the touch roll, to obtain a cheese-like package wound with 73 dtex/24 fibers.
The polyester yarn was then subjected to simultaneous draw-false-twist crimping under conditions of a draw ratio of 1.3, a false twist number of 2500 T/m (S direction), a heater temperature of 180° C., and a yarn speed of 350 m/min.

On the other hand, simultaneous stretch false twist crimping processing was carried out in the same manner as above, except that the twisting direction was changed to the Z direction.
Next, these false twisted crimped yarns having torque in the S direction and false twisted crimped yarns having torque in the Z direction were combined and subjected to air entanglement to obtain a composite yarn. The air entanglement was an interlace process using an interlace nozzle, and was performed at an overfeed rate of 1.0% and an air pressure of 0.3 MPa (3 kgf/ ^cm2 ). The physical properties of the obtained composite yarn are shown in Table 1.

[Example 2]
The same procedure as in Example 1 was repeated except that the fiber was extruded through a single row spinneret having 36 holes with a diameter of 0.27 mm to obtain a wound cheese-like package of 73 dtex/36 fibers.
The resulting fibers were then false-twisted and crimped under the same conditions as in Example 1 to obtain false-twisted crimp-textured yarns, and then composite yarns. The physical properties of the resulting composite yarns are shown in Table 1.

[Example 3]
The same procedure as in Example 1 was repeated except that the fiber was extruded through a single-row spinneret having 72 holes with a diameter of 0.27 mm to obtain a wound cheese-like package of 110 dtex/72 fibers.
The resulting fibers were then false-twisted and crimped under the same conditions as in Example 1 to obtain false-twisted crimp-textured yarns, and then composite yarns. The physical properties of the resulting composite yarns are shown in Table 1.

[Example 4]
The same procedure as in Example 1 was repeated except that the extrusion was carried out through a single row spinneret with 72 holes having a diameter of 0.20 mm to obtain a wound cheese-like package of 73 dtex/48 fibers.
The resulting fibers were then false-twisted and crimped under the same conditions as in Example 1 to obtain false-twisted crimp-textured yarns, and then composite yarns. The physical properties of the resulting composite yarns are shown in Table 1.

[Example 5]
The same procedure as in Example 1 was carried out except that the yarn was extruded through a spinneret having a single arrangement of 36 holes, using a spinneret with a cross-sectional shape having a slit width of 0.6 mm and a length of 1.2 mm, to obtain a cheese-like package wound with 109 dtex/36f fibers. The irregularity of the obtained irregular cross-section yarn was 2.2.
The resulting fibers were then false-twisted and crimped under the same conditions as in Example 1 to obtain false-twisted crimp-textured yarns, and then composite yarns. The physical properties of the resulting composite yarns are shown in Table 1.

[Example 6]
The same procedure as in Example 1 was carried out, except that the yarn was extruded through a spinneret having 36 holes and a single arrangement, using a die having a triangular cross section in which a slit having a width of 0.06 mm and a length of 0.5 mm extended in three directions from the center at an angle of 120°, to obtain a cheese-like package wound with 73 dtex/36 fibers. The irregularity of the obtained irregular cross section yarn was 1.6.
The resulting fibers were then false-twisted and crimped under the same conditions as in Example 1 to obtain false-twisted crimp-textured yarns, and then composite yarns. The physical properties of the resulting composite yarns are shown in Table 1.

[Example 7]
The same procedure as in Example 1 was carried out except that the yarn was extruded through a spinneret having 30 holes and a single arrangement, using a flat cross-sectional shape die with a slit width of 0.14 mm and a length of 1.4 mm, to obtain a wound cheese-like package of 73 dtex/30 fibers. The flatness of the obtained flat cross-sectional yarn was 3.4.
The resulting fibers were then false-twisted and crimped under the same conditions as in Example 1 to obtain false-twisted crimp-textured yarns, and then composite yarns. The physical properties of the resulting composite yarns are shown in Table 1.

[Comparative Example 1]
Melt spinning was carried out under the same conditions as in Example 1, and the solid multifilament was wound around a roll heated to 50°C and having a peripheral speed of 2510 m/min, and then wound at a winding speed of 2500 m/min to obtain a cheese-like package wound with 73 dtex/48 fibers.
The thermal stress peak of the obtained fiber was 0.08 cN/dtex at 55° C. The lowest elastic modulus of the fiber in the elongation range of 10 to 30% was 0 cN/dtex.
Next, the obtained fiber was false-twisted and crimped under the same conditions as in Example 1 in an attempt to obtain false-twisted and crimped yarn, but due to yarn breakage, false-twisted and crimped yarn could not be obtained.

[Comparative Example 2]
The same procedure as in Example 1 was repeated except that the fiber was extruded through a single-row spinneret having 12 holes with a diameter of 0.30 mm, to obtain a wound cheese-like package of 143 dtex/12 fibers.
The thermal stress peak of the obtained fiber was 0.08 cN/dtex at 55° C. The lowest elastic modulus of the fiber at elongation of 10% to 30% was 0 cN/dtex.
The resulting fibers were then false-twisted and crimped under the same conditions as in Example 1 to obtain false-twisted crimp-textured yarns, and then composite yarns. The physical properties of the resulting composite yarns are shown in Table 1.

[Comparative Example 3]
The fiber was extruded through a single-arranged spinneret with 36 holes having a diameter of 0.30 mm. The fiber was then wound around a roll heated to 50° C. and having a peripheral speed of 1500 m/min, stretched 2.0 times, and wound around a roll heated to 130° C. Then, the fiber was wound at a winding speed of 2900 m/min using a winder that drives both the spindle and the touch roll to obtain a cheese-like package of 95 dtex/36 fibers.
The thermal stress peak of the obtained fiber was 0.20 cN/dtex at 190° C. The lowest elastic modulus of the fiber in the elongation range of 10 to 30% was 3.3 cN/dtex.
The yarn thus obtained was then subjected to false twist crimp processing under the same conditions as in Example 1 except that the draw ratio was 1.1 to obtain a false twist crimp-processed yarn, and then a composite yarn was obtained. The physical properties of the composite yarn thus obtained are shown in Table 1.

[Comparative Example 4]
The same procedure as in Example 1 was repeated except that the fiber was extruded through a single-row spinneret having 72 holes with a diameter of 0.27 mm to obtain a wound cheese-like package of 110 dtex/72 fibers.
The polyester yarn was then subjected to simultaneous draw-false-twist crimping under conditions of a draw ratio of 1.3, a false twist number of 2500 T/m (S direction), a heater temperature of 180° C., and a yarn speed of 350 m/min.

Next, two false twisted crimped yarns having torque in the Z direction were combined and air entangled to obtain a composite yarn. The air entanglement was performed by interlacing using an interlace nozzle with an overfeed rate of 1.0% and an air pressure of 0.3 MPa (3 kgf/ ^cm2 ). The physical properties of the obtained composite yarn are shown in Table 1.

The present invention provides polytrimethylene terephthalate composite yarns that have little yarn breakage during the manufacturing process and have high shrink performance, despite their small single fiber fineness, as well as a manufacturing method and fabric for the same, and therefore has great industrial value.

Claims (7)

A polytrimethylene terephthalate composite yarn is obtained by mixing a false twisted crimped yarn made of polytrimethylene terephthalate having 90 mol % or more of trimethylene terephthalate repeating units and having torque in the S direction, and a false twisted crimped yarn made of polytrimethylene terephthalate having 90 mol % or more of trimethylene terephthalate repeating units and having torque in the Z direction, and is characterized in that the polytrimethylene terephthalate composite yarn simultaneously satisfies the following requirements (1) to (4):
(1) Single fiber fineness: 0.3 to 3.2 dtex
(2) Breaking strength ≧ 2.5 cN/dtex
(3) Shrinkage rate ≧10%
(4) Residual torque ≦ 30 T/m The polytrimethylene terephthalate composite yarn according to claim 1, having a total fineness of 10 to 400 dtex. The polytrimethylene terephthalate composite yarn according to claim 1, which is interlaced. The polytrimethylene terephthalate composite yarn according to claim 1, which contains modified cross-section fibers with a degree of modification of 1.15 to 10.0. The polytrimethylene terephthalate composite yarn according to claim 1, which contains flat cross-section fibers with a flatness of 2.0 to 10.0. A method for producing a polytrimethylene terephthalate composite yarn according to claim 1, wherein the false twisted crimp textured yarn having a torque in the S direction and the false twisted crimp textured yarn having a torque in the Z direction are produced by draw-false-twisting a polytrimethylene terephthalate fiber that simultaneously satisfies the following requirements (A) to (C):
(A) In the temperature-thermal stress curve of the fiber, there is a maximum value of thermal stress in the temperature range of 40 to 100°C.
(B) The maximum value of the thermal stress of (A) is 0.1 to 0.8 cN/dtex.
(C) The lowest elastic modulus at an elongation of 10 to 30% is 0.1 to 2 cN/dtex. A fabric comprising the polytrimethylene terephthalate composite yarn according to any one of claims 1 to 5.