Polytrimethylene terephthalate fiber and method for producing the same, air-blended yarn containing the polytrimethylene terephthalate fiber, and fabric made therefrom.

Abstract

The purpose of the present invention is to provide: a low-shrinkage fiber substantially composed of polytrimethylene terephthalate, and capable of producing a raw yarn for fabric that has a soft texture and a low heat shrinkage rate; a method for producing the low-shrinkage fiber; an air-mixed filament yarn that contains said polytrimethylene terephthalate fiber; and a fabric composed thereof. The present invention is a polytrimethylene terephthalate fiber composed of at least 90 mol% of trimethylene terephthalate repeating units, wherein the boiling water shrinkage rate of said polytrimethylene terephthalate fiber is at most 5%, and the elastic modulus at 20% elongation of said polytrimethylene terephthalate fiber is at most 5 cN / dtex.

Description

Technical Field

[0001] The present invention relates to a fiber substantially composed of polytrimethylene terephthalate, which can be used to produce a raw yarn for fabrics having a low heat-induced shrinkage and a soft hand feel, a method for producing the same, an air-mixed yarn comprising the polytrimethylene terephthalate fiber, and a fabric made therefrom .

Background Art

[0002] Polytrimethylene terephthalate (hereinafter sometimes referred to as PTT) has both properties similar to polyamide such as excellent elastic recovery and dyeability, and properties similar to polyethylene terephthalate such as light resistance, heat setting property, dimensional stability and low water absorption rate. By taking advantage of these characteristics, its application in many fields such as BCF carpets and brushes has been proposed (for example, Japanese Patent Application Laid-Open No. 9-3724, Japanese Patent Application Laid-Open No. 8-173244, Japanese Patent Application Laid-Open No. 5-262862, etc.). Furthermore, since polytrimethylene terephthalate fibers have a low Young's modulus, it is said that products with a soft hand feel can be obtained.

[0003] Regarding the method for producing polytrimethylene terephthalate fibers, a method has been proposed in which undrawn yarn melt-spun at 300 to 4000 m / min is continuously subjected to single-stage or multi-stage hot drawing at a temperature equal to or higher than the glass transition temperature of the undrawn yarn, after being wound up once or without being wound up. As spinning and drawing conditions in this process, for example, Japanese Patent Application Laid-Open No. 2001-207329 (Patent Document 1) discloses a method wherein a polytrimethylene terephthalate polymer having an intrinsic viscosity [η] of 0.7 or more is taken up at a spinning speed of 3000 m / min, subsequently drawn at 70°C without being wound up once, and then continuously subjected to relaxation heat treatment at a relaxation rate of 6 to 20%.

[0004] However, while conventionally proposed polytrimethylene terephthalate fibers do indeed have a lower Young's modulus compared to polyethylene terephthalate fibers, when used in fabrics, their properties are not fully realized, and a sufficiently satisfactory level of softness has not yet been achieved.

[0005] On the other hand, Japanese Patent Publication No. 2001-348729 (Patent Document 2) discloses that soft-textured polytrimethylene terephthalate fibers can be obtained by winding the yarn at a spinning speed of 4500 m / min or more. While this method does produce a soft fabric, it has problems such as the yarn becoming tightly wound due to elastic deformation of the yarn during winding, resulting in a poor winding shape and the collapse of the winding paper tube. Furthermore, the high spinning speed makes the yarn prone to breakage, making it difficult to produce a stable yarn. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2001-207329 [Patent Document 2] Japanese Patent Publication No. 2001-348729 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0007] The present invention has been made in view of the above background, and its purpose is to provide a low-shrinkage fiber substantially made of polytrimethylene terephthalate, a method for producing the same, which can be used to manufacture a yarn for woven fabrics that has a small thermal shrinkage rate and a soft texture, as well as an air-blended yarn containing the polytrimethylene terephthalate fiber, and a woven fabric made therefrom. [Means for solving the problem]

[0008] As a result of diligent research to solve the above problems, the present inventors have found that when the boiling water shrinkage rate (hereinafter sometimes referred to as the boiling water shrinkage rate) of a fiber substantially composed of polytrimethylene terephthalate and the modulus of elasticity at an elongation of 20% of the polytrimethylene terephthalate fiber are controlled to a range different from that of the so-called straight-drawn yarn and high-speed-spun yarn described in the above-mentioned prior art documents, a desired polytrimethylene terephthalate fiber can be obtained, leading to the present invention.

[0009] Thus, according to the present invention, A polytrimethylene terephthalate fiber comprising 1.90 mol% or more of repeating trimethylene terephthalate units, characterized in that the boiling water shrinkage rate of the polytrimethylene terephthalate fiber is 5% or less, and the modulus of elasticity at 20% elongation of the polytrimethylene terephthalate fiber is 5 cN / dtex or less. 2. The polytrimethylene terephthalate fiber described in 1 above, wherein the birefringence Δn of the polytrimethylene terephthalate fiber is 0.040 or more and the specific gravity is 1.350 or less. 3. The polytrimethylene terephthalate fiber described in 1 above, wherein the peak of the thermal stress of the polytrimethylene terephthalate fiber is located at 50-100°C and the peak value of the thermal stress is 0.2 cN / dtex or less. 4. The polytrimethylene terephthalate fiber described in item 1 above, wherein the tensile strength of the polytrimethylene terephthalate fiber is 1.5 to 3.5 cN / dtex and the elongation at break is 30 to 100%. A method for producing polytrimethylene terephthalate fibers, characterized by melting and solidifying polytrimethylene terephthalate composed of 5.90 mol% or more of repeating trimethylene terephthalate units, winding it at a winding speed of 1000 m / min or more, heating it on a heating roller at ±20°C of the glass transition point of the polytrimethylene terephthalate, then stretching it 1.0 to 2.0 times, winding it again on a heating roller at 50 to 150°C, winding it into a cheese-shaped package at a speed of 2000 to 4800 m / min, and then stretching the polytrimethylene terephthalate fibers wound into the cheese-shaped package by 1.1 times or more at a temperature below the glass transition point, and then shrinking the fibers by a factor of 0.5 to 0.9 times while heating. 6. An air-blended yarn characterized by containing a polytrimethylene terephthalate fiber described in any one of items 1 to 4 above and a polyester fiber. 7. The air-blended yarn described in 6 above, wherein the boiling water shrinkage rate of the polyester fiber is 7-50%. 8. The air-blended yarn described in 6 above, which includes fibers with a different cross-section. 9. An air-blended yarn obtained by heat-treating the air-blended yarn described in 6 above, comprising a core yarn and a sheath yarn, having a total fineness of 30 to 400 dtex, wherein the core yarn is made of polyester fibers, the sheath yarn is made of polytrimethylene terephthalate fibers with a single fiber fineness of 0.3 to 10 dtex, and the difference in yarn length between the core yarn and the sheath yarn, as defined by the method described below, is 5% or more. (Method for measuring thread length difference) After treating the blended yarn in boiling water, a load of 0.1 cN (0.098 g) × the total fineness (dtex) of the air-blended yarn is applied and the yarn is cut to a length of 5 cm. From the cut air-blended yarn, polyester fiber A (single fiber) and polytrimethylene terephthalate fiber B (single fiber) are extracted, and the length is measured by applying a load of 0.1 cN (0.098 g) × the single fiber fineness (dtex) to each, and the difference in yarn length (%) is calculated using the following formula. Thread foot difference (%)=(LB-LA) / LA×100 However, LA is the length (cm) of the polyester fiber core thread, and LB is the length (cm) of the polytrimethylene terephthalate fiber sheath thread. 10. The core-sheath type air-blended fiber described in item 9 above, wherein the weight ratio of the sheath yarn is 50-90% of the total weight of the core-sheath type air-blended fiber. 11. Core-sheath type air-blended yarn as described in 9 above, including fibers with a different cross-section. 12. The above 6 Fabrics containing the air-blended yarn described above, 13. The above 9 Fabrics containing the described core-sheath type air-blended yarn, It will be provided. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a low-shrinkage fiber substantially made of polytrimethylene terephthalate, a method for producing the same, which is capable of producing a yarn for woven fabrics that has a small thermal shrinkage rate and a soft texture, as well as an air-blended yarn containing the polytrimethylene terephthalate fiber, and a woven fabric made therefrom. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing an example of the degree of irregularity in the irregular cross-sectional fibers used in the present invention. [Figure 2] This is a schematic diagram showing examples of flattening in the flattened cross-section fibers used in the present invention. [Best Mode for Carrying Out the Invention]

[0012] The present invention will be described in detail below. (1) Polymer raw materials The polymer used in the present invention is polytrimethylene terephthalate (hereinafter sometimes referred to as PTT), 90 mol% or more of which is composed of trimethylene terephthalate repeating units. Here, PTT is a polyester using terephthalic acid as the acid component and trimethylene glycol (also referred to as 1,3-propanediol) as the diol component. The PTT may contain other copolymerization components in an amount of 10 mol% or less.

[0013] Examples of such copolymerization components include 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, tetrabutylphosphonium 3,5-dicarboxylic acid benzenesulfonate, tributylmethylphosphonium 3,5-dicarboxylic acid benzenesulfonate, 1,4-butanediol, neopentyl glycol, 1,6-hexamethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, adipic acid, dodecanedioic acid, and 1,4-cyclohexanedicarboxylic acid. and other ester-forming monomers.

[0014] If necessary, various additives such as delustrants, heat stabilizers, defoamers, color regulators, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, crystal nucleating agents, fluorescent whitening agents, etc. may be copolymerized or mixed with the above PTT.

[0015] The polytrimethylene terephthalate polymer used in the present invention preferably has an intrinsic viscosity [η] of 0.5 to 1.6, more preferably 0.6 to 1.5, and even more preferably 0.7 to 1.4.

[0016] When the intrinsic viscosity is less than 0.5, the molecular weight of the polymer is too low, which may make it difficult to develop strength; on the other hand, when the intrinsic viscosity exceeds 1.6, the fluidity is low, which impairs the spinnability of low-viscosity polytrimethylene terephthalate and may cause yarn breakage during spinning, which is not preferable.

[0017] (2) Polytrimethylene terephthalate fiber The polytrimethylene terephthalate fiber of the present invention exhibits minimal deformation upon hot water treatment, resulting in less shrinkage of the yarn and a softer texture when used in fabric. Furthermore, a characteristic of this polytrimethylene terephthalate fiber is its low elastic modulus above the primary yield point in tensile strength and elongation measurements. Therefore, fabrics made using this fiber have a more flexible drape compared to fabrics made with ordinary polytrimethylene terephthalate fiber.

[0018] As for the yarn properties of such polytrimethylene terephthalate fibers, the boiling water shrinkage rate (hereinafter sometimes referred to as boiling water shrinkage rate) of the polytrimethylene terephthalate fibers in this application must be 5% or less, preferably 4% or less, and more preferably 3% or less. If the boiling water shrinkage rate is greater than 5%, the fabric becomes stiff due to shrinkage of the yarn caused by heat.

[0019] Furthermore, the polytrimethylene terephthalate fiber of the present invention must have an elastic modulus of 5 cN / dtex or less at an elongation of 20%, preferably 4 cN / dtex or less, and more preferably 3 cN / dtex or less. If the elastic modulus at an elongation of 20% is greater than 5 cN / dtex, the fabric will become stiff after subsequent dyeing and processing.

[0020] Furthermore, the birefringence Δn of the polytrimethylene terephthalate fiber of the present invention is preferably 0.040 or more and 0.08 or less. More preferably, the birefringence Δn is 0.045 or more and 0.075 or less, and even more preferably, the birefringence Δn is 0.050 or more and 0.070 or less. If the birefringence Δn is less than 0.040, the yarn strength will be low, and the fabric will stretch under external force, making it difficult to maintain its shape, which is undesirable.

[0021] Furthermore, the specific gravity, which serves as an alternative indicator of the degree of crystallinity of the polytrimethylene terephthalate fiber of the present invention, is preferably 1.350 or less, and more preferably 1.319 or more and 1.350 or less. If the specific gravity is less than 1.319, the yarn becomes brittle during the stretching and false twisting process, resulting in frequent yarn breakage and making the stretching and false twisting process difficult. On the other hand, if the specific gravity is greater than 1.350, a lot of fluffing occurs, which is undesirable.

[0022] Furthermore, it is preferable that the thermal stress peak of the polytrimethylene terephthalate fiber of the present invention is located between 50°C and 100°C. If the peak is located at a temperature lower than 50°C, the heat resistance will be low, which is undesirable. Also, if the peak is located at a temperature higher than 100°C, the degree of crystallinity will be too high, resulting in a loss of flexible drape, which is also undesirable.

[0023] Furthermore, it is preferable that the peak thermal stress value of the polytrimethylene terephthalate fiber of the present invention be 0.2 cN / dtex or less. If the peak thermal stress value is greater than 0.2 cN / dtex, deformation due to hot water treatment such as dyeing will be greater, which is undesirable because the yarn will shrink and become stiff when made into a fabric.

[0024] Furthermore, the tensile strength of the polytrimethylene terephthalate fiber of the present invention is 1.5 cN / dtex or more to 3.5 cN / dtex, preferably 1.7 cN / dtex to 3.3 cN / dtex, and more preferably 2.0 cN / dtex to 3.0 cN / dtex.

[0025] If the tensile strength of the polytrimethylene terephthalate fiber is less than 1.5 cN / dtex, the durability of the product will decrease, which is undesirable. Conversely, if the tensile strength of the polytrimethylene terephthalate fiber is greater than 3.5 cN / dtex, the degree of crystallinity will become too high, resulting in a loss of flexible drape, which is also undesirable.

[0026] The elongation at break of polytrimethylene terephthalate fibers is preferably between 30% and 100%. If the elongation at break of polytrimethylene terephthalate fibers is less than 30%, the degree of crystallinity becomes too high, resulting in a loss of flexible drape, which is undesirable. On the other hand, if the elongation at break of polytrimethylene terephthalate fibers is greater than 100%, the fibers stretch when a load is applied, resulting in poor dimensional stability, which is also undesirable.

[0027] (3) Method for producing polytrimethylene terephthalate fibers Polytrimethylene terephthalate fibers as described above can be manufactured, for example, by the following manufacturing method. First, polytrimethylene terephthalate, which consists of more than 90 mol% repeating units of trimethylene terephthalate, is melted and solidified. Then it is wound up at a winding speed of 1000 m / min or more, subsequently heated on a heated roller at ±20°C of the glass transition point of polytrimethylene terephthalate, then stretched 1.0 to 2.0 times, and after being wound onto a heated roller at 50 to 150°C, it is wound into a cheese-like package at a speed of 2000 to 4800 m / min.

[0028] In this way, polytrimethylene terephthalate fibers with a breaking elongation of 50-200% wound onto a cheese-shaped package are stretched by 1.1 times or more at a temperature below the glass transition point of the polytrimethylene terephthalate, and then, while heating, the fibers are shrunk by a factor of 0.5-0.9 to obtain polytrimethylene terephthalate fibers that exhibit small thermal shrinkage and can be used to make fabrics with a soft texture.

[0029] In this case, the total stretch ratio, which is the product of the stretch ratio at a temperature below the glass transition temperature and the shrinkage ratio while heating, is preferably 0.9 to 1.25 times, and more preferably 0.95 to 1.20 times. If the total stretch ratio is less than 0.90 times, the yarn may loosen, and the yarn's movement during stretching may become unstable, which can lead to yarn breakage, so this is undesirable. Also, if the total stretch ratio is greater than 1.25 times, the yarn's shrinkage rate may become too high, which may result in a fabric that does not have a soft texture, so this is also undesirable.

[0030] Furthermore, molten and solidified polytrimethylene terephthalate fibers with a breaking elongation of 50-200% can also be manufactured by, for example, winding them at a spinning speed of 1000 m / min or more, and then stretching them at a low magnification of 1.0-2.0 times at a temperature of ±20°C from the glass transition point of polytrimethylene terephthalate.

[0031] Furthermore, it is possible to wind the fibers onto a heated roller at a spinning speed of 4000 m / min or more and then wind them onto a winding machine. Among these methods, there is no problem in heating the polytrimethylene terephthalate fibers with a heated roller at 50-150°C before winding, in order to suppress winding tightness when directly winding the fibers onto the winding machine.

[0032] The high-elongation polytrimethylene terephthalate fibers obtained in this manner are preferably 50-200% or more in elongation at break. More preferably 60-190%, and even more preferably 70-180%.

[0033] If the elongation at break of the high-elongation polytrimethylene terephthalate fiber is less than 50%, the crystallization of the fiber becomes high, making it undesirable as it prevents the creation of a soft-textured fabric. On the other hand, if the elongation at break exceeds 200%, crystallization does not progress when stretched at temperatures below the glass transition point, resulting in significantly low strength and poor durability when used as a fabric, which is also undesirable.

[0034] Next, the melted and solidified polytrimethylene terephthalate fibers are stretched to 1.1 times or more, more preferably 1.2 times or more, and more preferably 1.3 times or more at a temperature below the glass transition temperature of polytrimethylene terephthalate, more preferably below the glass transition temperature of -5°C, and even more preferably below the glass transition temperature of -10°C.

[0035] In this case, stretching at a temperature higher than the glass transition temperature is undesirable because it results in a high degree of crystallinity, making it impossible to produce a soft-textured fabric. Also, stretching at a ratio lower than 1.1 times is undesirable because it reduces the durability of the fabric.

[0036] Furthermore, since the stretched fibers have not undergone significant crystallization and exhibit high polymer orientation, resulting in low thermal dimensional stability, dimensional stability and durability can be improved by shrinking the fibers at a ratio of 0.5 to 0.9 times while heating them.

[0037] In this case, if the fiber shrinkage is less than 0.5 times, the degree of orientation and crystallinity of the resulting polytrimethylene terephthalate fibers becomes too low, which is undesirable because it reduces the durability of the fabric. Also, if the fiber shrinkage is greater than 0.9 times, the degree of crystallinity becomes too high, which is undesirable because it prevents the creation of a soft-textured fabric.

[0038] (4) Polyester fibers (for core thread) In the present invention, the above-mentioned polytrimethylene terephthalate fiber and polyester fiber are blended by air processing to obtain an air-blended yarn.

[0039] Preferably, the polyester fibers used in this process include polytrimethylene terephthalate (PTT) fibers, polyethylene terephthalate (PET) fibers, side-by-side or eccentric core-sheath composite fibers of polytrimethylene terephthalate and polyethylene terephthalate, side-by-side or eccentric core-sheath composite fibers of polytrimethylene terephthalate and polyethylene terephthalate, and side-by-side or eccentric core-sheath composite fibers of polyethylene terephthalate and polyethylene terephthalate, which are fibers spun and drawn by conventional methods. There is no problem in adding additives such as antistatic agents, flame retardants, heat resistant agents, weather resistant agents, and titanium dioxide. In such polyester fibers, when applying heat treatment or the like to the air-blended yarn to increase the difference in length between the core yarn and the sheath yarn, it is preferable that the boiling water shrinkage rate is 7 to 50%.

[0040] (5) Method for manufacturing air-blended yarn Next, the polytrimethylene terephthalate fiber is used as the sheath yarn, and the polyester fiber is used as the core yarn. These are then entangled using air processing (interlace or Taslan®) (preferably 30 to 150 entangles / m), and the resulting air-blended yarn is obtained by drawing it up with a roller. The overfeed rate during air blending is preferably 0.5 to 2%.

[0041] Furthermore, the air-blended yarn of the present invention may contain fibers with irregular cross-sections other than round cross-sections. For example, it can be composed of fibers with irregular cross-sections such as cruciate, triangular, or star-shaped cross-sections, thereby obtaining a unique texture. Here, the degree of irregularity of the irregular cross-section fibers is calculated as follows, as shown in Figure 1: Degree of Irregularity = R / r, by measuring the maximum inscribed circle diameter r and the minimum circumscribed circle diameter R of the fiber cross-section. The value of Degree of Irregularity = R / r is preferably 1.15 to 10.0, and more preferably 1.2 to 10.0. If the degree of irregularity is less than 1.15, the difference from a round cross-section may become small. Also, if the degree of irregularity exceeds 10.0, the orientation difference between the outer and inner sides of the yarn cross-section becomes large during spinning, and the resulting yarn may have a lot of fluff and slack, making it unsuitable for processing.

[0042] Furthermore, flattened cross-section fibers are also given as examples of irregularly shaped cross-section fibers. Using flattened cross-section fibers is preferable because it can provide a unique texture. Here, the flatness of a flattened cross-section fiber is calculated as flatness = L / H by drawing a rectangle circumscribing the fiber cross-section, measuring the long side L and short side H, as shown in Figure 2. In the present invention, the value of flatness = L / H is preferably between 2.0 and 10.0. If the flatness is less than 2.0, the difference from a round cross-section may become small. Also, if the flatness exceeds 10.0, fluffing may easily occur during spinning, potentially leading to poor stability.

[0043] The resulting air-blended yarn can be made into a core-sheath type air-blended yarn with a large difference in length between the core and sheath, using a low-shrinkage fiber made of polytrimethylene terephthalate, which has a soft texture, as the sheath yarn.

[0044] (6) Method for manufacturing core-sheath type air-blended yarn In the present invention, by subjecting the above-mentioned air-blended yarn to heat treatment such as dyeing, the polytrimethylene terephthalate fibers become sheath threads and the polyester fibers become core threads, resulting in a core-sheath type air-blended yarn containing core threads and sheath threads.

[0045] In such air-blended yarns, the single fiber fineness of the sheath yarn must be 0.3 to 10 dtex, more preferably 0.5 to 8 dtex, and even more preferably 0.6 to 5 dtex. If the single fiber fineness is greater than 10 dtex, the softness of the fabric may be lost due to the thickness of the single fibers. If the single fiber fineness is less than 0.3 dtex, the yarn may break frequently, making it impossible to manufacture the fibers. The number of single fibers (filaments) in the sheath yarn is preferably 20 to 150. On the other hand, the single fiber fineness of the core yarn is preferably 1.0 to 5.0 dtex. The number of single fibers (filaments) in the core yarn is preferably 12 to 100.

[0046] Furthermore, in the core-sheath type air-blended yarn of the present invention, the total fineness must be 30 to 400 dtex, and more preferably 50 to 200 dtex. If the total fineness is less than 30 dtex, the total fineness may be too fine, making air-blended processing difficult. On the other hand, if the total fineness is greater than 400 dtex, the softness of the fabric may be lost. The number of single fibers (number of filaments) is preferably 40 to 400 (more preferably 40 to 200).

[0047] In the above-described core-sheath type air-blended yarn, it is essential that the difference in yarn length between the core yarn and the sheath yarn, as defined below, is 5% or more (more preferably 6-40%). If the difference in yarn length is less than 5%, sufficient fullness cannot be obtained.

[0048] The above yarn length difference is calculated by treating the aforementioned air-blended yarn in boiling water, then applying a load of 0.1 cN (0.098 g) × the total fineness (dtex) of the air-blended yarn and cutting it to a length of 5 cm. From the cut air-blended yarn, polyester fiber A (single fiber) and polytrimethylene terephthalate fiber B (single fiber) are extracted, and the length is measured by applying a load of 0.1 cN (0.098 g) × the single fiber fineness (dtex) to each, and the yarn length difference (%) is calculated using the following formula. Thread foot difference (%)=(LB-LA) / LA×100 However, LA is the length (cm) of the polyester fiber core thread, and LB is the length (cm) of the polytrimethylene terephthalate fiber sheath thread.

[0049] Furthermore, in the core-sheath type air-blended yarn of the present invention, it is preferable that the polytrimethylene terephthalate fibers of the sheath yarn constitute 50-90% (more preferably 60-80%) of the weight of the blended yarn. If the weight ratio of polytrimethylene terephthalate fibers of the sheath yarn is 50% or less, not only will a soft texture not be obtained, but the difference in dyeing between the core yarn and the sheath yarn may become more visible.

[0050] (7) Method for manufacturing a fabric made of core-sheath type air-blended yarn In this invention, a woven fabric (raw material) is obtained by knitting or weaving using the aforementioned air-blended yarn, and then dyeing and sweat-absorbing processes are applied as appropriate to obtain a finished woven fabric. At that time, the heat treatment during the dyeing process causes a difference in the length of the sheath yarn and core yarn of the blended yarn, resulting in a woven fabric made of core-sheath type air-blended yarn.

[0051] Here, the fabric may be constructed using only core-sheath type air-blended yarn, or it may be constructed using core-sheath type air-blended yarn and other yarns. In this case, the other yarns are not particularly limited and may be any of the following: un-crimped yarn, false-twist crimped yarn, latent crimped yarn, spun yarn, etc.

[0052] The structure of the woven fabric is not particularly limited and may be either knitted or woven. Examples include knitted fabrics with knitting structures such as jersey, knit mis, smooth, rib knit, pique, quilted knit, denby, and half, and woven fabrics with weaving structures such as plain weave, twill weave, and satin, but are not limited to these. The number of layers may be single or multi-layered with two or more layers.

[0053] Next, the aforementioned fabric may be used to produce textile products such as sportswear, outerwear, innerwear, men's clothing, women's clothing, nursing care clothing, work clothes, car seat upholstery, and bedding. Since such fabrics and textile products use the aforementioned air-blended yarn, they have a soft texture and excellent fullness. [Examples]

[0054] The following describes examples and comparative examples of the present invention in detail, but the present invention is not limited thereto. The measurement items in the examples were measured using the methods described below.

[0055] (1) Intrinsic viscosity [η] The intrinsic viscosity [η] was determined using an Ostwald viscometer at 35°C in o-chlorophenol by extrapolating the ratio ηsp / C (specific viscosity ηsp to concentration C (g / 100 ml)) to zero concentration, according to the following equation (1). [η] = lim(ηsp / C) ···(1) C→0

[0056] (2) Glass transition temperature The glass transition point was determined by sealing a specified amount of polymer chips in an aluminum sample pan and measuring the temperature rise curve from room temperature to 300°C at a heating rate of 10°C / min using DSC under a nitrogen atmosphere.

[0057] (3) Fineness (fineness of multifilament yarn) The fineness of the multifilament yarn was measured according to JIS-L-1013. The single-filament fineness was then determined by dividing this value by the number of single filaments in the multifilament yarn.

[0058] (4) Boiling Water Contraction Rate (BWS) Based on JIS-L-1013, the fiber was measured using a measuring machine with a frame circumference of 1.125m, with an initial load of 1 / 30g of decitex applied and the fiber was wound back, creating a 20-turn skein. A load of 1.11g of decitex was then applied and the skein length was measured. Next, the load was removed, the skein was immersed in 100°C hot water for 30 minutes, removed, air-dried, and the load was applied again to measure the skein length. The boiling water shrinkage rate was then calculated using the following formula. Boiling water shrinkage rate (%)={(L0-L1) / L0}×100 Here, L0: length of the cable before immersion (mm), L1: length of the cable after immersion (mm)

[0059] (5) Breaking strength, breaking elongation Measurements were taken using a constant-speed elongation tensile testing machine, Tensilon, manufactured by Orientec Co., Ltd., in accordance with JIS-L-1013, with a gripping distance of 20 cm and a tensile speed of 20 cm / min.

[0060] (6) Modulus of elasticity at 20% elongation Measurements were taken using a constant-speed elongation tensile testing machine, Tensilon, manufactured by Orientec Co., Ltd., in accordance with JIS-L-1013, with a gripping distance of 20 cm and a tensile speed of 20 cm / min. The slope of the tangent to the SS curve at 20% elongation was determined as the modulus of elasticity at 20% elongation.

[0061] (7) Specific gravity The specific gravity of the sample was measured according to the buoyancy method of JIS-L-1013 8.17.1.

[0062] (8) Birefringence Δn The properties were determined from the polarization retardation observed on the surface of the fibers using an optical microscope and compensator, in accordance with the Textile Handbook - Raw Materials, p. 969 (5th printing, published by Maruzen Co., Ltd. in 1978).

[0063] (9) Temperatures at which thermal stress maxima exist and the thermal stress maxima A KE-2 microscope manufactured by Kanebo Engineering Co., Ltd. was used. Measurements were taken 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 x-axis and thermal stress on the y-axis to create a temperature-thermal stress curve. The temperature and thermal stress at the point where the derivative of the temperature-thermal stress curve changes from positive to negative were determined, and the stress was divided by the fineness to find the maximum stress.

[0064] (10) Confounding number Air-processed yarn was measured to a length of 1m under a load of 8.82mNx (0.1g / dtex), and after de-loading, the number of knots was read after 24 hours of release at room temperature and expressed as knots / m.

[0065] (11) Thread difference After treating the yarn in the same manner as the boiling water shrinkage rate described above, a load of 0.1 cN (0.098 g) × the total fineness (dtex) of the air-blended yarn is applied and the yarn is cut to a length of 5 cm. From the cut air-blended yarn, polyester fiber A (single fiber) and polytrimethylene terephthalate fiber B (single fiber) are taken out, and a load of 0.1 cN (0.098 g) × the single fiber fineness (dtex) is applied to each, and the length is measured. The difference in yarn length (%) is calculated using the following formula. Thread foot difference (%)=(LB-LA) / LA×100 However, LA is the length (cm) of the polyester fiber core thread, and LB is the length (cm) of the polytrimethylene terephthalate fiber sheath thread.

[0066] (12) Texture The testers touched the air-blended yarn with their hands and evaluated it on a three-point scale: ○ (plump and soft), △ (average), and × (poorly puffy or hard).

[0067] [Example 1] Dimethyl terephthalate and 1,3-propanediol were charged in a 1:2 molar ratio, and titanium tetrabutoxide equivalent to 0.1% by weight of dimethyl terephthalate was added. The transesterification reaction was completed at a heater temperature of 240°C under atmospheric pressure. Next, 0.1% by weight of titanium tetrabutoxide and 0.5% by weight of titanium dioxide were added, and the reaction was carried out at 270°C for 3 hours.

[0068] The resulting polymer consisted of 100 mol% trimethylene terephthalate repeating units, and its intrinsic viscosity was 1.0 dl / g. The glass transition temperature of the resulting polymer was 51°C. The obtained polymer was dried by conventional methods to reduce its moisture content to 50 ppm, then melted at 265°C and extruded through a single-arranged spindle with 36 holes, each with a diameter of 0.27 mm.

[0069] The extruded molten multifilament was rapidly cooled by applying an airflow of 4.0 m / min to convert it into a solid multifilament. Then, using a guide nozzle, an oil containing 60% by weight of octyl stearylate, 15% by weight of polyoxyethylene alkyl ether, and 3% by weight of potassium phosphate was applied as a 10% by weight water emulsion finishing agent so that the amount of oil adhering to the fibers was 0.6% by weight.

[0070] Next, the solid multifilament was wound onto a roll heated to 50°C at a peripheral speed of 2100 m / min, then wound onto a roll heated to 80°C to be stretched to 1.3 times its original length, and then wound onto a winding machine that drives both a spindle and a touch roll at a winding speed of 2600 m / min to obtain a cheese-shaped package wound with 72 dtex / 36 filament fibers.

[0071] Subsequently, the fibers wound in the package were stretched 1.5 times at 30°C, heated with a 190°C contact heating plate heater to shrink the fibers to 0.7 times their original size, and wound up at a speed of 600 m / min to obtain low-shrinkage polytrimethylene terephthalate fibers (yarn for sheath threads). On the other hand, as the core thread, a polyester (polyethylene terephthalate) drawn yarn (total fineness 56 dtex / 36 strands, boiling water shrinkage rate 10%) was prepared.

[0072] Next, the sheath yarn and the core yarn were interlaced with an overfeed rate of 1.5% to obtain an air-blended yarn with an entanglement count of 69 threads / m. The physical properties of the obtained polytrimethylene terephthalate fibers are shown in Table 1, and the physical properties of the blended yarn are shown in Table 2.

[0073] [Example 2] After producing a polymer in the same manner as in Example 1, the obtained polymer was dried by conventional methods to reduce the moisture content to 50 ppm, then melted at 265°C and extruded through a double-arranged spindle with 72 holes and a diameter of 0.23 mm.

[0074] After applying an oil to the extruded molten multifilament in the same manner as in Example 1, the solid multifilament was wound onto a roll heated to 50°C at a peripheral speed of 2100 m / min, then wound onto a roll heated to 80°C to be stretched by 1.3 times, and then wound onto a winding machine that drives both a spindle and a touch roll at a winding speed of 2600 m / min to obtain a cheese-shaped package wound with 72 dtex / 72 filament fibers.

[0075] Subsequently, the fibers wound in the package were stretched 1.4 times at 30°C, heated with a 190°C contact heating plate heater to shrink the fibers to 0.75 times their original size, and wound up at a speed of 600 m / min to obtain low-shrinkage polytrimethylene terephthalate fibers (yarn for sheath threads). On the other hand, as the core thread, a polyester (polyethylene terephthalate) drawn yarn (total fineness 56 dtex / 36 strands, boiling water shrinkage rate 13%) was prepared.

[0076] Next, the sheath yarn and the core yarn were aligned and interlaced with an overfeed rate of 1.5% in the same manner as in Example 1 to obtain an air-blended yarn with an entanglement count of 71 threads / m. The physical properties of the obtained polytrimethylene terephthalate fibers are shown in Table 1, and the physical properties of the blended yarn are shown in Table 2.

[0077] [Example 3] After preparing the polymer in the same manner as in Example 1, the obtained polymer was dried by conventional methods to reduce the moisture content to 50 ppm, then melted at 265°C and extruded through a single-arranged spindle with 36 holes, each with a diameter of 0.27 mm.

[0078] After applying an oil to the extruded molten multifilament in the same manner as in Example 1, the solid multifilament was wound onto a roll heated to 50°C at a peripheral speed of 2350 m / min, then wound onto a roll heated to 80°C to be stretched by 1.1 times, and then wound onto a winding machine that drives both a spindle and a touch roll at a winding speed of 2600 m / min to obtain a cheese-shaped package wound with 72 dtex / 36 filament fibers.

[0079] Subsequently, the fibers wound in the package were stretched 1.6 times at 30°C, heated with a 190°C contact heating plate heater to shrink the fibers to 0.65 times their original size, and wound up at a speed of 600 m / min to obtain low-shrinkage polytrimethylene terephthalate fibers (yarn for sheath threads). On the other hand, as a core thread, a conjugate drawn yarn (total fineness 56 dtex / 24 strands, boiling water shrinkage rate 17%) made by laminating two polyester components (polyethylene terephthalate / polyethylene terephthalate) was prepared.

[0080] Next, the sheath yarn and the core yarn were aligned and interlaced with an overfeed rate of 1.5% in the same manner as in Example 1 to obtain an air-blended yarn with an entanglement count of 65 threads / m. The physical properties of the obtained polytrimethylene terephthalate fibers are shown in Table 1, and the physical properties of the blended yarn are shown in Table 2.

[0081] [Example 4] After preparing the polymer in the same manner as in Example 1, the obtained polymer was dried by conventional methods to reduce the moisture content to 50 ppm, then melted at 265°C and extruded through a single-arranged spindle with 36 holes, each with a diameter of 0.27 mm.

[0082] After applying an oil to the extruded molten multifilament in the same manner as in Example 1, the solid multifilament was wound onto a roll heated to 50°C at a peripheral speed of 3000 m / min, then wound onto a roll heated to 80°C to be stretched to 1.2 times its original length, and then wound onto a winding machine that drives both a spindle and a touch roll at a winding speed of 3600 m / min to obtain a cheese-shaped package wound with 56 dtex / 36 filament fibers.

[0083] Subsequently, the fibers wound in the package were stretched 1.3 times at 30°C, heated with a 190°C contact heating plate heater to shrink the fibers to 0.85 times their original size, and wound up at a speed of 600 m / min to obtain low-shrinkage polytrimethylene terephthalate fibers (yarn for sheath threads). On the other hand, as a core thread, a conjugate drawn yarn (total fineness 33 dtex / 24 strands, boiling water shrinkage rate 21%) made by laminating polyethylene terephthalate and polytrimethylene terephthalate was prepared.

[0084] Next, the sheath yarn and the core yarn were aligned and interlaced with an overfeed rate of 1.5% in the same manner as in Example 1 to obtain an air-blended yarn with an entanglement count of 71 threads / m. The physical properties of the obtained polytrimethylene terephthalate fibers are shown in Table 1, and the physical properties of the blended yarn are shown in Table 2.

[0085] [Examples 5-6] In Example 1, the procedure was carried out in the same manner as in Example 1, except that the cross-sectional shape and number of single fibers of the sheath yarn were changed as shown in Table 1. The physical properties of the obtained polytrimethylene terephthalate fibers are shown in Table 1, and the physical properties of the blended yarn are shown in Table 2.

[0086] [Comparative Example 1] After preparing the polymer in the same manner as in Example 1, the obtained polymer was dried by conventional methods to reduce the moisture content to 50 ppm, then melted at 265°C and extruded through a single-arranged spindle with 36 holes, each with a diameter of 0.27 mm.

[0087] After applying an oil to the extruded molten multifilament in the same manner as in Example 1, the solid multifilament was wound onto a roll heated to 55°C at a peripheral speed of 1500 m / min, then wound onto a roll heated to 130°C to be stretched by 2.1 times, and then wound onto a winding machine that drives both a spindle and a touch roll at a winding speed of 3000 m / min to obtain a cheese-shaped package wound with 72 dtex / 36 filament fibers (polytrimethylene terephthalate fiber yarn for sheath threads). On the other hand, as the core thread, a polyester (polyethylene terephthalate) drawn yarn (total fineness 56 dtex / 36 strands, boiling water shrinkage rate 12%) was prepared.

[0088] Next, the sheath yarn and the core yarn were aligned and interlaced with an overfeed rate of 1.5% in the same manner as in Example 1 to obtain an air-blended yarn with an entanglement count of 65 threads / m. The physical properties of the obtained polytrimethylene terephthalate fibers are shown in Table 1, and the physical properties of the blended yarn are shown in Table 2. The resulting air-blended yarn had little difference in length between the core and sheath, and lacked volume.

[0089] [Comparative Example 2] After preparing the polymer in the same manner as in Example 1, the obtained polymer was dried by conventional methods to reduce the moisture content to 50 ppm, then melted at 265°C and extruded through a single-arranged spindle with 36 holes, each with a diameter of 0.27 mm.

[0090] After applying an oil to the extruded molten multifilament in the same manner as in Example 1, the solid multifilament was wound onto a roll heated to 55°C at a peripheral speed of 1500 m / min, then wound onto a roll heated to 130°C to be stretched by 2.1 times, and then wound onto a winding machine that drives both a spindle and a touch roll at a winding speed of 3000 m / min to obtain a cheese-shaped package wound with 56 dtex / 36 filament fibers.

[0091] Subsequently, the fibers wound in the package were stretched 1.05 times at 30°C, heated with a 190°C contact heating plate heater to shrink the fibers to 0.92 times their original size, and wound up at a speed of 600 m / min to obtain tritrimethylene terephthalate fibers (yarn for sheath threads). On the other hand, as the core thread, a polyester (polyethylene terephthalate) drawn yarn (total fineness 56 dtex / 36 strands, boiling water shrinkage rate 10%) was prepared.

[0092] Next, the sheath yarn and the core yarn were aligned and interlaced with an overfeed rate of 1.5% in the same manner as in Example 1 to obtain an air-blended yarn with an entanglement count of 63 threads / m. The physical properties of the obtained polytrimethylene terephthalate fibers are shown in Table 1, and the physical properties of the blended yarn are shown in Table 2. The resulting air-blended yarn had stiff sheath threads and an inferior texture.

[0093] [Table 1]

[0094] [Table 2] [Industrial applicability]

[0095] According to the present invention, it is possible to provide a low-shrinkage fiber substantially made of polytrimethylene terephthalate, a method for producing the same, which can be used to manufacture a yarn for fabrics that has a small thermal shrinkage rate and a soft texture, as well as an air-blended yarn containing the polytrimethylene terephthalate fiber, and a fabric made therefrom, and therefore its industrial value is extremely great.

Claims

1. A polytrimethylene terephthalate fiber comprising 90 mol% or more of repeating trimethylene terephthalate units, characterized in that the boiling water shrinkage rate of the polytrimethylene terephthalate fiber is 5% or less, and the modulus of elasticity at 20% elongation of the polytrimethylene terephthalate fiber is 5 cN / dtex or less.

2. The polytrimethylene terephthalate fiber according to claim 1, wherein the birefringence Δn of the polytrimethylene terephthalate fiber is 0.040 or more and the specific gravity is 1.350 or less.

3. The polytrimethylene terephthalate fiber according to claim 1, wherein the peak of the thermal stress of the polytrimethylene terephthalate fiber is located at 50 to 100°C, and the peak value of the thermal stress is 0.2 cN / dtex or less.

4. The polytrimethylene terephthalate fiber according to claim 1, wherein the tensile strength of the polytrimethylene terephthalate fiber is 1.5 to 3.5 cN / dtex and the elongation at tensile strength is 30 to 100%.

5. A method for producing polytrimethylene terephthalate fibers, characterized by melting and solidifying polytrimethylene terephthalate composed of 90 mol% or more of repeating trimethylene terephthalate units, winding it at a winding speed of 1000 m / min or more, heating it on a heating roller at ±20°C of the glass transition point of the polytrimethylene terephthalate, then stretching it 1.0 to 2.0 times, winding it further on a heating roller at 50 to 150°C, winding it into a cheese-shaped package at a speed of 2000 to 4800 m / min, and then stretching the polytrimethylene terephthalate fibers wound into the cheese-shaped package by 1.1 times or more at a temperature below the glass transition point, and then shrinking the fibers at a ratio of 0.5 to 0.9 times while heating.

6. An air-blended yarn characterized by comprising a polytrimethylene terephthalate fiber according to any one of claims 1 to 4 and a polyester fiber.

7. The air-blended yarn according to claim 6, wherein the boiling water shrinkage rate of the polyester fiber is 7 to 50%.

8. The air-blended yarn according to claim 6, comprising fibers with a different cross-section.

9. An air-blended yarn of the core-sheath type, obtained by heat-treating the air-blended yarn described in claim 6, comprising a core yarn and a sheath yarn, having a total fineness of 30 to 400 dtex, wherein the core yarn is made of polyester fibers, the sheath yarn is made of polytrimethylene terephthalate fibers with a single fiber fineness of 0.3 to 10 dtex, and the difference in yarn length between the core yarn and the sheath yarn, as defined by the method described below, is 5% or more. (Method for measuring thread length difference) After treating the blended yarn in boiling water, a load of 0.1 cN (0.098 g) × the total fineness (dtex) of the air-blended yarn is applied and the yarn is cut to a length of 5 cm. From the cut air-blended yarn, polyester fiber A (single fiber) and polytrimethylene terephthalate fiber B (single fiber) are extracted, and a load of 0.1 cN (0.098 g) × the single fiber fineness (dtex) is applied to each, and the length is measured. The difference in yarn length (%) is calculated using the following formula. Thread length difference (%) = (LB-LA) / LA x 100 However, LA is the length (cm) of the polyester fiber core thread, and LB is the length (cm) of the polytrimethylene terephthalate fiber sheath thread.

10. The core-sheath type air-blended yarn according to claim 9, wherein the weight ratio of the sheath yarn is 50 to 90% of the total weight of the core-sheath type air-blended yarn.

11. The core-sheath type air-blended yarn according to claim 9, comprising fibers with a different cross-section.

12. A fabric containing air-blended yarn as described in claim 6.

13. A fabric containing the core-sheath type air-blended yarn described in claim 9.

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