Polyether ester elastic fiber, wound yarn of same, textile containing same, and article of clothing

Abstract

Provided is a polyether ester elastic fiber having good stretch and recovery properties, having sufficient heat resistance to inhibit a decrease in tensile stress and fabric wrinkling due to shrinkage even after undergoing a dyeing process, and having good aesthetic properties as a fabric. Also provided are a wound yarn of said fiber, a textile containing said fiber, and an article of clothing. A polyether ester elastic fiber according to the present invention has a total denier between 5 dtex and 80 dtex, inclusive, a phase separation index between 0.20 and 0.65, inclusive, as measured by a small-angle X-ray scattering device, and a hard-domain fiber axial orientation index of 10.00 or less as measured by Raman spectroscopy.

Description

Polyetherester elastic fiber, wound body of said fiber, fabric containing said fiber, and clothing

[0001] The present invention relates to a polyether ester elastic fiber, a wound body of the fiber, and a fabric and clothing containing the fiber.

[0002] Elastic fibers are widely used in clothing such as legwear, innerwear, sportswear, and swimwear, as well as in non-clothing fields such as disposable diapers, bandages, supports, masks, etc. In particular, elastic fibers for clothing applications must have stretchability and stretch recovery properties when stretched and recovered, as well as aesthetic appeal so that streaks, wrinkles, open mesh, and clogged mesh caused by irregularities in the knitting structure or weaving structure are not noticeable when processed and dyed into fabric, and polyurethane elastic fibers are widely known as fibers that have these properties.

[0003] On the other hand, polyether ester elastic fibers are elastic fibers composed of hard segments composed of aromatic polyester units and soft segments composed of polyalkylene ether glycol units. These segments form a microphase-separated structure consisting of hard domains, soft domains, and phase mixtures of soft and hard domains, based on the balance between the cohesive forces of the same components and the repulsive forces that act against phase growth. The hard domains function as physical crosslinking points, and the soft domains function as stretchable sites. Therefore, the balance of the microphase-separated structure composed of each domain allows the fiber to exhibit properties such as stretchability, stretch recovery, and heat resistance.

[0004] As shown in Figure 1, stretchability is expressed as R / S, which is the ratio of the stress at stretch (S-modulus) to the stress at recovery (R-modulus) when a polyether ester elastic fiber is stretched and recovered. The larger the R / S of a polyether ester elastic fiber, the better the stretchability and the better the fit when made into a fabric. As shown in Figure 2, stretchability recovery is expressed as the recovery rate when a polyether ester elastic fiber is stretched and recovered. The higher the recovery rate of a polyether ester elastic fiber, the better the stretchability recovery and the less likely it is to slacken. Heat resistance refers to the change in tensile stress of a polyether ester elastic fiber during the dyeing process, the degree of shrinkage, and whether or not thread breakage occurs.

[0005] In general, polyether ester elastic fibers are inferior to polyurethane elastic fibers in terms of stretchability, stretch recovery, and heat resistance. If the hard domain content of the polymer is reduced and the soft domain content is increased in order to improve the stretchability and stretch recovery of polyether ester elastic fibers, the melting point of the polyether ester elastic fibers will be significantly reduced, which will cause problems such as a decrease in tensile stress due to heat applied in the dyeing process, shrinkage causing wrinkles in the fabric, and thread breakage in the fabric.

[0006] Patent Document 1 below discloses a polyetherester elastic fiber that has good stretch recovery properties by increasing the hard segment content to 50% or more to raise the melting point of the polymer and by heat-treating the fiber in a cheese-wrapped state to increase the orientation and crystallinity of the hard domains in the fiber axis direction. However, the polyetherester elastic fiber described in Patent Document 1 does not have good stretch compliance. This is thought to be because the hard domains are highly oriented in the fiber axis direction, and therefore, when the polyetherester elastic fiber is stretched and recovered, the hard domains are destroyed by the elongation stress. Furthermore, the polyetherester elastic fiber described in Patent Document 1 has the problem of shrinkage and deterioration of physical properties during the dyeing process, which is thought to be due to relaxation of the hard domains oriented in the fiber axis direction during the dyeing process.

[0007] Furthermore, Patent Document 2 below discloses a production method for exhibiting stretch recovery properties of polyether ester elastic fibers by controlling the speeds of the take-up roll and the drawing roll, performing melt spinning at an extremely high take-up speed of 3,000 m / min or more, and highly orienting the hard domains in the fiber axis direction. However, the polyether ester elastic fibers described in Patent Document 2 do not have good stretch tracking properties. This is presumably because the hard domains are highly oriented, and therefore, when the polyether ester elastic fibers are stretched and recovered, the hard domains are destroyed by the elongation stress. Furthermore, the polyether ester elastic fibers described in Patent Document 2 exhibit significant shrinkage and deterioration in physical properties during dyeing processes, which is presumably due to relaxation of the hard domains oriented in the fiber axis direction during the dyeing process.

[0008] Furthermore, Patent Document 3 below discloses a polyetherester elastic fiber that has been stretched after spinning to enhance the orientation of hard domains in the fiber axis direction, thereby improving its stretch compliance and stretch recovery. However, the polyetherester elastic fiber described in Patent Document 3 is prone to shrinkage during the dyeing process. This is presumably because the hard domains in the polyetherester elastic fiber described in Patent Document 3 are highly oriented in the fiber axis direction, and the orientation state of the hard domains is relaxed during the dyeing process. As such, a polyetherester elastic fiber that has good stretch compliance and stretch recovery and can sufficiently suppress a decrease in tensile stress and the occurrence of wrinkles in the fabric during the dyeing process has not yet been developed.

[0009] Japanese Patent Laid-Open No. 11-107042 Japanese Patent Laid-Open No. 2019-210571 Japanese Patent Laid-Open No. 2009-167541

[0010] In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a polyether ester elastic fiber that has good elasticity and recovery from elasticity, and that has heat resistance sufficient to sufficiently suppress the occurrence of wrinkles in fabrics due to a decrease in tensile stress and shrinkage even after dyeing and processing, and that has good aesthetic properties as a fabric; a wound body of the fiber; and a fabric and clothing containing the fiber.

[0011] As a result of intensive research and repeated experiments to solve the above-mentioned problems, the inventors of the present application unexpectedly discovered that the above-mentioned problems can be solved by increasing the composition ratio of both the hard domains and the soft domains and / or by controlling the orientation of the hard domains in the fiber axis direction to be low, and have completed the present invention.

[0012] That is, the present invention is as follows. [1] A polyetherester elastic fiber having a total fineness of 5 dtex to 80 dtex, a phase separation index of 0.20 to 0.65 as measured by a small-angle X-ray scattering device, and an orientation index of the hard domains in the fiber axis direction of 10.00 or less as measured by Raman spectroscopy. [2] The polyetherester elastic fiber according to [1] above, in which 80 mol % or more of the low-molecular-weight diol units constituting the polyetherester are selected from the group consisting of 1,4-butanediol, 1,6-hexanediol, 1,3-propanediol, and ethylene glycol, and 50 mol % or more of the polymer polyol units are PTMG or a copolymer diol composed of tetrahydrofuran (THF) and neopentyl glycol. [3] The polyetherester elastic fiber according to [1] or [2] above, having a reduced viscosity of 2.00 dL / g to 6.00 dL / g. [4] The polyetherester elastic fiber according to any one of [1] to [3] above, wherein the orientation index in the fiber axis direction of the phase mixture of the soft domain and the hard domain, measured by Raman spectroscopy, is 2.50 or more and 5.00 or less. [5] The polyetherester elastic fiber according to any one of [1] to [4] above, wherein the orientation index in the fiber axis direction of the soft domain, measured by Raman spectroscopy, is 1.50 or more and 4.00 or less. [6] A wound yarn of the polyetherester elastic fiber according to any one of [1] to [5] above. [7] A fabric comprising the polyetherester elastic fiber according to any one of [1] to [5] above. [8] A garment comprising the polyetherester elastic fiber according to any one of [1] to [5] above.

[0013] The polyether ester elastic fiber of the present invention, having the above-described configuration, has good stretchability and stretch recovery properties, and can sufficiently suppress a decrease in tensile stress and the occurrence of wrinkles in the fabric even after dyeing and finishing processes. Furthermore, since the fiber of the present invention can sufficiently suppress the occurrence of wrinkles in the fabric, it is suitable for fabrics and clothing that can exhibit aesthetic appeal as a fabric. Furthermore, a wound body of the fiber, which is one aspect of the present invention, has good unwinding properties and excellent running stability during processing, and can form a uniform greige weave, resulting in excellent aesthetic appeal. Furthermore, fabrics and clothing containing the fiber, which are another aspect of the present invention, suppress a decrease in stress and the occurrence of wrinkles in the dyeing and finishing processes, and have a good sense of power and fit when worn, and are aesthetically pleasing.

[0014] 1A and 1B are schematic diagrams illustrating measurement of stretchability and recovery.

[0015] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following embodiment, and various modifications can be made within the scope of the present invention.

[0016] [Polyetherester Elastic Fiber] One embodiment of the present invention is a polyetherester elastic fiber having a total fineness of 5 dtex or more and 80 dtex or less, a phase separation index of 0.20 or more and 0.65 or less as measured by a small-angle X-ray scattering device, and / or an orientation index of the hard domains in the fiber axis direction as measured by Raman spectroscopy of 10.00 or less.

[0017] In the present invention, the polyether ester elastomer constituting the polyether ester elastic fiber is not particularly limited as long as it has a structure in which dicarboxylic acid units, low-molecular-weight diol units, and polymer polyol units are copolymerized. Furthermore, the polymerization method is also not particularly limited. Tri- or higher-functional carboxylic acid units and glycol units may be used within a range that does not impair the desired effects of the present invention.

[0018] Examples of the dicarboxylic acid unit include aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and aliphatic dicarboxylic acids. Examples of the aromatic dicarboxylic acid include, but are not limited to, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxydicarboxylic acid, and 5-sulfoisophthalic acid.

[0019] Examples of alicyclic dicarboxylic acids and aliphatic dicarboxylic acids include sebacic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, dodecanedioic acid, glutaric acid, succinic acid, oxalic acid, azelaic acid, dimethylmalonic acid, fumaric acid, citraconic acid, allylmalonic acid, 4-cyclohexene-1,2-dicarboxylic acid, pimelic acid, suberic acid, 2,5-diethyladipic acid, 2-ethylsuberic acid, 2,2,3,3-tetramethylsuccinic acid, cyclopentanenedicarboxylic acid, decahydro-1,5-(or 2,6-)naphthalenedicarboxylic acid, 4,4'-bicyclohexyldicarboxylic acid, 4,4'-methylenebis(cyclohexylcarboxylic acid), 3,4-furandicarboxylate, and 1,1-cyclobutanedicarboxylate. These dicarboxylic acid units may be used alone or in combination of two or more. In particular, from the viewpoint of improving the elastic fiber's stretchability, stretch recovery, and heat resistance, the dicarboxylic acid unit is preferably an aromatic dicarboxylic acid, and more preferably terephthalic acid.

[0020] The low-molecular-weight diol unit is a diol compound having a molecular weight of 500 or less, and examples thereof include, but are not limited to, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol. These diol units may be used alone or in combination of two or more. From the viewpoint of improving the stretchability, stretch recovery, and heat resistance of the elastic fiber, the diol unit is preferably ethylene glycol, 1,3-propanediol, or 1,4-butanediol.

[0021] In the polyether ester elastic fiber of this embodiment, from the viewpoint of improving stretchability and stretch recovery upon stretch recovery, and further enhancing the effects of suppressing deterioration in physical properties and suppressing shrinkage during the dyeing process, it is preferable to use 80 mol % or more of any one of 1,4-butanediol, 1,3-propanediol, and ethylene glycol as the low molecular weight diol units constituting the polyether ester elastomer, more preferably 90 mol % or more, even more preferably 95 mol % or more, and most preferably 98 mol % or more. By using any one of 1,4-butanediol, 1,3-propanediol, and ethylene glycol as 80 mol % or more of the low molecular weight diol units constituting the polyether ester elastomer, it is easier to control the orientation of the hard domains and the orientation of the phase mixture portion of the soft domains and the hard domains to a low level, thereby improving stretchability and stretch recovery upon stretch recovery, and enhancing the effects of suppressing deterioration in physical properties and suppressing shrinkage during the dyeing process. Furthermore, since the fabric is less likely to shrink during the dyeing process, wrinkles are less likely to occur in the fabric, improving aesthetics.

[0022] Examples of the polymer polyol unit include, but are not limited to, polymer diols such as polyether-based diols, polyester-based diols, polycarbonate-based diols, etc. From the viewpoint of improving the hydrolysis resistance of the polyetherester elastic fiber, the polymer polyol unit is preferably a polyether-based polyol, and more preferably a polyether-based diol.

[0023] Examples of polyether-based polyols include polyethylene oxide, polyethylene glycol, polyethylene glycol derivatives, polypropylene glycol, polytetramethylene ether glycol (PTMG), modified PTMG (hereinafter also referred to as "PTXG"), which is a copolymer diol composed of tetrahydrofuran (THF) and neopentyl glycol, and a copolymer diol composed of THF and 3-methyltetrahydrofuran. These polyether-based polyols may be used alone or in combination of two or more. Furthermore, the number-average molecular weight of the polymer polyol is preferably 1,000 to 8,000. By using a polymer polyol within this range, elastic fibers with excellent elongation, stretch recovery, stretch tracking, and heat resistance can be easily obtained. From the viewpoint of improving stretch tracking, the polyether-based polyol is preferably polytetramethylene ether glycol (PTMG) or a copolymer diol composed of tetrahydrofuran (THF) and neopentyl glycol (PTXG).

[0024] In the polyether ester elastic fiber of this embodiment, from the viewpoint of improving the stretchability and stretch recovery properties upon stretching and recovery, and further enhancing the effects of suppressing deterioration of physical properties and suppressing shrinkage during the dyeing process, it is preferable to use 50 mol % or more, more preferably 60 mol % or more, of either PTMG or PTXG as the polymer polyol units constituting the polyether ester elastomer. By using PTMG or PTXG in 50 mol % or more of the polymer polyol units constituting the polyether ester elastomer, it is easy to control the orientation of the soft domains and the orientation of the phase mixture portion of the soft domains and the hard domains to a low level, thereby improving the stretchability and stretch recovery properties upon stretching and recovery, and the effect of suppressing shrinkage during the dyeing process. Furthermore, since the fabric is less likely to shrink during the dyeing process, wrinkles are less likely to occur in the fabric, improving aesthetics.

[0025] In the polyether ester elastomer constituting the polyether ester elastic fiber of this embodiment, the ratio of hard segments composed of dicarboxylic acid units and low-molecular-weight diol units to soft segments composed of polymer polyol units is preferably 15:85 to 50:50 by weight.

[0026] In the polyether ester elastic fiber of this embodiment, from the viewpoint of achieving both improved stretchability and stretch recovery upon stretching and recovery, and suppression of shrinkage in the dyeing process, the total fineness must be 5 dtex or more and 80 dtex or less. By setting the total fineness to 5 dtex or more and 80 dtex or less, it becomes easy to control the temperature profile of the yarn during the cooling process in the melt spinning process, and it becomes easy to control the orientation of the hard domains, soft domains, and soft-and-hard domain phase mixture portions of the polyether ester elastic fiber in the fiber axial direction to a low level, thereby achieving all of the effects of improved stretchability and stretch recovery, and suppression of shrinkage in the dyeing process. Furthermore, since the fabric is less likely to shrink in the dyeing process, it is less likely to wrinkle, and aesthetic appeal can be achieved.

[0027] The number of filaments in the polyether ester elastic fiber of the present embodiment is not particularly limited as long as the desired effects of the present invention are not lost. However, from the viewpoints of suppressing unevenness in physical properties and fineness between filaments and maintaining the cohesiveness of the filaments in the dyeing process, the number is preferably 1 or more and 60 or less, more preferably 1 or more and 20 or less.

[0028] In the polyether ester elastic fiber of this embodiment, from the viewpoint of achieving both improved stretchability and stretch recovery upon stretching and recovery, and suppressing the deterioration of physical properties and shrinkage during the dyeing process, the phase separation index measured with a small-angle X-ray scattering device is preferably 0.20 or more and 0.65 or less. By achieving a phase separation index measured with a small-angle X-ray scattering device of 0.20 or more, the composition ratio of the soft domain / hard domain phase mixture can be reduced and the composition ratio of the hard domain / soft domain can be increased. This allows the hard domain and soft domain to fully demonstrate their respective functions during stretching and recovery of the polyether ester elastic fiber, thereby achieving satisfactory stretchability and stretch recovery. Furthermore, since the composition ratio of the soft domain / hard domain phase mixture, which is prone to change in phase separation structure during the dyeing process, is low, structural changes upon application of heat during the dyeing process can be minimized, thereby achieving satisfactory effects of suppressing the deterioration of physical properties and shrinkage during the dyeing process. Furthermore, since the fabric is less likely to shrink during the dyeing process, wrinkles are less likely to occur on the fabric, and aesthetic appeal can be achieved. The phase separation index measured by a small angle X-ray scattering device is preferably 0.25 or more.

[0029] On the other hand, if the phase separation index measured by a small-angle X-ray scattering device exceeds 0.65, when the polyether ester elastic fiber is stretched and recovered, the elongation stress is concentrated in the hard domain, resulting in high elongation stress and poor stretch-followability. Furthermore, since the phase separation structure of the polyether ester elastic fiber is highly developed, when the hard domain structure is destroyed by stretch recovery, the change in the phase separation structure is greatly affected, and the structure does not return to its original state during recovery, resulting in poor stretch-recovery. The phase separation index measured by a small-angle X-ray scattering device is preferably 0.55 or less.

[0030] In the polyether ester elastic fiber of this embodiment, from the viewpoint of achieving both improved stretchability and stretch recovery upon stretching and recovery, and the effects of suppressing deterioration of physical properties and shrinkage in the dyeing process, it is preferable that the orientation index in the fiber axis direction of the hard domains measured by Raman spectroscopy is 10.00 or less. The orientation index in the fiber axis direction of the hard domains is, as will be described in detail later, determined by the Raman spectroscopy method using a Raman spectroscopy method based on the 1550 cm ―１ and 1650 cm ―１ The Raman spectrum is connected with a straight line, and the area of ​​the enclosed area is calculated, and the ratio indicates the area of ​​the parallel scattering spectrum / the area of ​​the perpendicular scattering spectrum. By setting the orientation index of the hard domains in the fiber axis direction as measured by Raman spectroscopy to 10.00 or less, the proportion of the elongation stress applied to the hard domains among the elongation stresses applied to the polyether ester elastic fiber during elongation and recovery can be reduced, suppressing the destruction of the hard domains and thereby achieving satisfactory stretchability and stretch recovery of the polyether ester elastic fiber. Furthermore, because the degree of orientation of the hard domains in the fiber axis direction is low, relaxation of the hard domain structure is reduced even when heat is applied in the dyeing process, thereby achieving satisfactory effects of suppressing deterioration of physical properties and shrinkage in the dyeing process, while also achieving aesthetic appeal of the fabric. The orientation index of the hard domains in the fiber axis direction as measured by Raman spectroscopy is preferably 9.00 or less, and more preferably 8.00 or less.

[0031] On the other hand, the orientation index of the hard domains in the fiber axis direction of the polyether ester elastic fiber measured by Raman spectroscopy is preferably 5.00 or more. If the orientation index of the hard domains in the fiber axis direction measured by Raman spectroscopy is less than 5.00, the orientation of each hard domain in the fiber axis direction is low, so that the hard domains do not function sufficiently as crosslinking points during stretching and recovery, resulting in poor stretch tracking and stretch recovery. Furthermore, the orientation of the hard domains in the polyether ester elastic fiber in the fiber axis direction is low, so that the structure relaxes when heat is applied in the dyeing process, resulting in poor physical properties in the dyeing process. The orientation index of the hard domains in the fiber axis direction measured by Raman spectroscopy is preferably 6.00 or more, more preferably 6.50 or more.

[0032] In the polyether ester elastic fiber of the present invention, from the viewpoint of improving stretchability and stretch recovery upon stretch recovery, and further enhancing the effects of suppressing deterioration of physical properties and shrinkage during dyeing and finishing, the reduced viscosity is preferably 2.00 dL / g or more, more preferably 3.00 dL / g or more. By achieving a reduced viscosity of 2.00 dL / g or more, molecular mobility can be reduced, making it less likely that hard domains will break upon stretch recovery, thereby improving stretchability and stretch recovery upon stretch recovery. Furthermore, since molecular mobility is low and the hard domain structure is less likely to relax even when heat is applied during the dyeing and finishing process, deterioration of physical properties and shrinkage during the dyeing and finishing process can be suppressed. Furthermore, since the fabric is less likely to shrink during the dyeing and finishing process, wrinkles are less likely to occur on the fabric, improving aesthetics. On the other hand, there is no particular upper limit for the reduced viscosity of the polyether ester elastic fiber, but it is practically difficult for it to exceed 6.00 dL / g, and it is more preferably 5.00 dL / g or less. Polyether ester elastic fibers having a reduced viscosity of 6.00 dL / g or less can have a low degree of soft domain orientation, which improves the ability to follow stretching and recovery after elongation and improves the effect of suppressing shrinkage during dyeing and finishing.

[0033] In the polyether ester elastic fiber of this embodiment, from the viewpoint of improving the stretchability and stretch recovery properties when stretched and recovered, and further enhancing the effects of suppressing the deterioration of physical properties and shrinkage in the dyeing process, the orientation index in the fiber axis direction of the phase mixture portion of the soft domains and the hard domains, as measured by Raman spectroscopy, is preferably 2.50 or more and 5.00 or less, more preferably 3.00 or more and 4.50 or less, and even more preferably 3.50 or more and 4.30 or less. The orientation index in the fiber axis direction of the phase mixture portion of the soft domains and the hard domains, as will be described in detail later, is determined by the angle .theta. of the parallel scattering spectrum and the perpendicular scattering spectrum at 1650 cm. ―１ and 1810 cm ―１ The distance between the two points is 1720 cm. ―１A perpendicular line was dropped from the point, and the area enclosed by the low-wavenumber Raman spectrum, the straight line, and the perpendicular line was calculated, and the ratio refers to the area of ​​the parallel scattering spectrum divided by the area of ​​the perpendicular scattering spectrum. By achieving an orientation index of 2.50 or higher in the fiber axis direction of the soft and hard domain phase mixture measured by Raman spectroscopy, the hard and soft domains can function as crosslinking points and stretchable sites, respectively, during stretch recovery, thereby further improving stretch compliance and stretch recovery during stretch recovery. Furthermore, the soft and hard domain phase mixture is partially oriented in the fiber axis direction, which reduces the degree of relaxation when heat is applied during the dyeing process, further improving the effects of suppressing deterioration of physical properties and shrinkage during the dyeing process. Furthermore, the fabric is less likely to shrink during the dyeing process, which reduces wrinkles and further improves aesthetics. Furthermore, by lowering the orientation index in the fiber axis direction of the soft domain / hard domain phase mixture portion measured by Raman spectroscopy to 5.00 or less, the movement of the soft domain / hard domain phase mixture portion in the fiber axis direction during stretch recovery is facilitated, and destruction of the soft domain / hard domain phase mixture portion can be suppressed, thereby further improving the stretch followability and stretch recovery when the polyether ester elastic fiber is stretched and recovered. Furthermore, since the degree of orientation of the phase mixture portion is low and the degree of relaxation when heat is applied in the dyeing process is small, deterioration of physical properties and shrinkage in the dyeing process can be further suppressed and the aesthetics of the fabric can be further improved.

[0034] In the polyether ester elastic fiber of this embodiment, from the viewpoint of improving the stretchability and stretch recovery properties when stretched and recovered, and further enhancing the effects of suppressing the deterioration of physical properties and shrinkage in the dyeing process, the orientation index in the fiber axis direction of the soft domains measured by Raman spectroscopy is preferably 1.50 or more and 4.00 or less, more preferably 2.00 or more and 3.50 or less, and even more preferably 2.50 or more and 3.30 or less. The orientation index in the fiber axis direction of the soft domains is, as will be described in detail later, determined by the Raman spectroscopy method using a Raman spectroscopy method based on the 1650 cm ―１ and 1810 cm ―１ The distance between the two points is 1720 cm. ―１A perpendicular line was dropped from the center of the fiber, and the area enclosed by the high-wavenumber Raman spectrum, the straight line, and the perpendicular line was calculated, and the area of ​​the parallel scattering spectrum / the area of ​​the perpendicular scattering spectrum was calculated. By increasing the orientation index of the soft domains in the fiber axis direction measured by Raman spectroscopy to 1.50 or more, the soft domains can easily function as stretchable sites during stretch recovery, further improving stretch compliance and stretch recovery. Furthermore, since the soft domains are partially oriented in the fiber axis direction and the degree of relaxation when heat is applied during the dyeing process is small, the effects of suppressing deterioration in physical properties and shrinkage during the dyeing process can be further improved, and the aesthetic appeal of the fabric can be further improved. By decreasing the orientation index of the soft domains in the fiber axis direction measured by Raman spectroscopy to 4.00 or less, movement of the soft domains in the fiber axis direction during stretch recovery can be facilitated, suppressing destruction of the soft domains, thereby further improving stretch compliance and stretch recovery during stretch recovery of polyether ester elastic fibers. Furthermore, since the degree of orientation in the fiber axis direction is low and the degree of relaxation when heat is applied during the dyeing process is small, deterioration of physical properties and shrinkage during the dyeing process can be further suppressed and the aesthetic appearance of the fabric can be further improved.

[0035] The polyetherester elastic fiber of this embodiment can further enhance the effect of improving the aesthetic appearance of the fabric by having a certain amount of fineness unevenness in the yarn length direction. The fineness unevenness in the yarn length direction of the polyetherester elastic fiber is preferably 3.00% to 11.50%, more preferably 3.50% to 11.00%, and even more preferably 4.00% to 10.50%. When the fineness unevenness of the polyetherester elastic fiber is 3.00% or more, the morphology of the polyetherester elastic fiber due to the fineness unevenness varies during knitting and weaving, making it possible to widely distribute the degree of clogging and opening in the texture constituting the gray fabric, thereby improving the overall aesthetic appearance. On the other hand, when the fineness unevenness in the yarn length direction exceeds 11.50%, the tension fluctuates greatly during knitting and weaving, making localized clogging and opening in the gray fabric texture more likely to occur, which becomes more noticeable during the dyeing process, thereby impairing the aesthetic appearance of the fabric.

[0036] The polyether ester elastic fiber of this embodiment can further enhance the effect of improving the aesthetic appearance of fabrics by having a certain range of distortion in the cross-sectional shape of a single yarn. The diameters of the circumscribing circle with the smallest diameter that completely encompasses the cross section of the polyether ester elastic fiber and the inscribing circle with the largest diameter that completely encompasses the cross section are measured, and the ratio of these diameters, i.e., the circumscribing circle diameter / inscribing circle diameter, is preferably 1.006 or more and 1.100 or less, more preferably 1.008 or more and 1.090 or less, and even more preferably 1.010 or more and 1.080 or less. By making the ratio of the circumscribing circle diameter / inscribing circle diameter 1.006 or more, when knitting or weaving using the polyether ester elastic fiber, the morphology of the polyether ester elastic fiber varies due to unevenness in the cross-sectional shape, making it possible to widely distribute the degree of clogging and opening in the structure that constitutes the gray fabric, thereby improving the aesthetic appearance of the fabric. On the other hand, if the ratio of circumscribed circle diameter / inscribed circle diameter exceeds 1.100, it becomes difficult for the yarn to run stably over the knitting needles during knitting of the fabric, and therefore the stitch structure of the grey fabric cannot be formed uniformly, impairing the aesthetic appeal of the fabric.

[0037] The polyether ester elastic fiber of this embodiment has a small change in stress during elongation, thereby further enhancing the effect of improving the aesthetic quality of the fabric. The ratio of the stress at 200% elongation to the stress at 150% elongation of the polyether ester elastic fiber is preferably 1.06 to 1.40, more preferably 1.08 to 1.35, and even more preferably 1.10 to 1.30. By making the ratio of the stress at 200% elongation to the stress at 150% elongation 1.06 or more, uneven elongation of the fiber is less likely to occur with respect to the elongation draft when knitting the gray fabric, and the knitted structure becomes uniform, thereby improving the aesthetic quality of the fabric. On the other hand, if the ratio of the stress at 200% elongation to the stress at 150% elongation exceeds 1.40, the running stress and elongation of the polyether ester elastic fiber are likely to vary when the polyether ester elastic fiber is run to knit or weave, causing clogging or opening in the structure constituting the gray fabric, thereby impairing the aesthetic quality of the fabric.

[0038] Although the method for producing the polyether ester elastic fiber of this embodiment is not particularly limited, one embodiment of melt spinning will be described below. The polyether ester elastomer used as the raw material for the polyether ester elastic fiber is a polyether ester elastomer composed of a dicarboxylic acid unit, a polymer polyol, and a low-molecular-weight diol in a molar ratio of preferably 1.00:0.05-0.40:0.60-0.95, more preferably 1.00:0.10-0.30:0.70-0.90.

[0039] To the polyether ester elastomer used as a raw material for the polyether ester elastic fiber, known additives such as hindered phenol-based oxidation stabilizers, hindered amine-based oxidation stabilizers, phosphorus-based oxidation stabilizers, sulfur-based oxidation stabilizers, triazole-based light stabilizers, etc. may be added in order to prevent thermal degradation of the polymer during the spinning process and coloration of the polyether ester elastic fiber when it is used. These additives may be used alone or in combination of two or more.

[0040] Furthermore, the polyether ester elastic fiber may contain polymers other than the polyether ester elastomer or additives, such as gas discoloration inhibitors, dyes, matting agents, crystal nucleating agents, lubricants, etc., to the extent that the desired effects are not lost.

[0041] Known crystal nucleating agents can be used, including, for example, organic crystal nucleating agents such as sodium, potassium, and lithium salts of aliphatic, alicyclic, or aromatic carboxylic acids having from 3 to 40 carbon atoms, and inorganic crystal nucleating agents such as talc, calcium carbonate, titanium oxide, magnesium oxide, calcium sulfate, barium sulfate, and sodium silicate. The amount of the crystal nucleating agent added can be 0.01 parts by mass or more and 10 parts by mass or less based on the polyether ester elastic fiber.

[0042] The melt spinning method is not particularly limited as long as the desired physical properties are obtained, but for example, chips of polyether ester elastomer are fed into an extruder, heated and melted, and then metered by a gear pump and introduced into a spinning head. If necessary, foreign matter is removed by filtration using a wire mesh, glass beads, or the like within the spinning head, and the mixture is then discharged from a spinneret, air-cooled in a cold air chamber, treated with a treating agent, passed through a godet roll, and wound up at a constant speed by a winder.

[0043] The polyether ester elastomer chips fed into the extruder are preferably dried in a dryer to a moisture content of 300 ppm or less, from the viewpoint of suppressing hydrolysis in the extruder or spinning head.

[0044] In the polyether ester elastic fiber of this embodiment, the total fineness can be adjusted by adjusting the balance between the amount of polymer discharged from the spinneret during spinning and the winding speed of the winder.

[0045] The cross-sectional shape of the single yarn and the unevenness of the fineness can be controlled by using a spinneret with a non-circular shape for the melt spinning, by enlarging the diameter to generate draw resonance, by increasing the output rate to generate sharkskin or melt fracture, or by changing the cooling intensity during the spinning process to cause yarn sway.

[0046] In the melt spinning process, the extrusion temperature, cold air speed, cold air temperature, and spinning speed are adjusted to precisely control the temperature profile and spinning tension of the fiber. The die temperature is preferably 180°C or higher and 280°C or lower, more preferably 200°C or higher and 260°C or lower. A common melt spinning cooling method, such as applying cold air directly below the spinneret perpendicular to the running direction of the yarn, is used. The cold air speed is preferably 0.2 m / sec or higher and 3.0 m / sec or lower, more preferably 0.5 m / sec or higher and 1.5 m / sec or lower, and the cold air temperature is preferably 5°C or higher and 25°C or lower, more preferably 7°C or higher and 20°C or lower.

[0047] In the polyether ester elastic fiber of this embodiment, the phase separation index before and after elongation recovery measured with a small-angle X-ray scattering device can be easily adjusted to 0.20 or more and 0.65 or less by methods such as increasing the temperature at which the polyether ester elastomer is discharged from the spinneret during spinning, adding a crystal nucleating agent to promote the formation of a microphase-separated structure, or increasing the distance from the spinneret to the winder, or by adjusting the applied thermal history.

[0048] In the polyether ester elastic fiber of this embodiment, the orientation of the hard domains, the soft domains, and the phase mixture of the soft and hard domains can be easily controlled by installing a heating cylinder below the spinneret to keep the yarn warm or strictly controlling the temperature and speed of cold air during the spinning process. In the polyether ester elastic fiber, the orientation index in the fiber axis direction of the hard domains, as measured by Raman spectroscopy, can be easily adjusted to 5.00 or more and 10.00 or less by maintaining the temperature of the yarn 10 cm below the spinneret at 70°C or more, more preferably 80°C or more, even more preferably 90°C or more, and most preferably 100°C or more during the spinning process and significantly reducing the cooling rate of the yarn directly below the spinneret. Furthermore, by strictly controlling the temperature and speed of cold air from 10 cm to 50 cm below the spinneret in the spinning process and maintaining the yarn temperature 50 cm below the spinneret at 40° C. or higher, more preferably 45° C. or higher, and most preferably 50° C. or higher, it becomes easy to adjust the fiber axis orientation index of the soft domain and hard domain phase mixture portion, measured by Raman spectroscopy, to 2.50 or higher and 5.00 or lower. Furthermore, by strictly controlling the temperature and speed of cold air from 50 cm to 100 cm below the spinneret in the spinning process and slowly cooling the yarn so that the temperature 100 cm below the spinneret is 30° C. or higher, more preferably 35° C. or higher, and most preferably 40° C. or higher, it becomes easy to adjust the fiber axis orientation index of the soft domain, measured by Raman spectroscopy, to 1.50 or higher and 4.00 or lower. Furthermore, from the viewpoint of stably controlling the yarn temperature at points 10 cm, 50 cm, and 100 cm directly below the spinneret within the above-mentioned ranges during the spinning process by adjusting the heater barrel and the cold air temperature and speed, the winding speed of the winder is preferably 2000 m / min or less, more preferably 1500 m / min or less, and most preferably 1000 m / min or less.

[0049] In the polyether ester elastic fiber of the present embodiment, when the fiber is a multifilament having two or more filaments, in order to improve the bundling property, a false twisting machine may be installed between the spinneret and the godet roll, and the twist is propagated from below by varying the strength of the twist, thereby bundling the filaments and controlling the height of the bundling point. A general method for false twisting can be selected, and air false twisting using an air nozzle or a ring false twisting machine in which the filaments are brought into contact with a rotating ring can be used.

[0050] In the polyetherester elastic fiber of this embodiment, a treatment agent such as an oil may be applied to the polyetherester elastic fiber from the viewpoint of improving the reeling property, processability, etc. Examples of the treatment agent include, but are not limited to, silicone-based oils such as dimethyl silicone, mineral oils, and combinations thereof. The method for applying the treatment agent is not particularly limited, and examples include application using an oiling roller, etc. The amount of the treatment agent attached to the polyetherester elastic fiber is preferably 0.5 parts by mass or more and 10 parts by mass or less based on the fiber weight.

[0051] Another embodiment of the present invention is a wound body of elastic fibers comprising the polyether ester elastic fibers.

[0052] Another embodiment of the present invention is a fabric containing the polyether ester elastic fiber as an elastic fiber. The fabric of this embodiment refers to knitted fabrics having various knitting structures such as circular knitted fabrics, weft knitted fabrics, and warp knitted fabrics, and woven fabrics in general, and is made of elastic fibers and inelastic fibers. As the inelastic fiber, any fiber can be used, including synthetic fibers such as polyamide fibers, polyester fibers, polypropylene, and acrylic fibers, cellulosic fibers such as cupra, rayon, cotton, and bamboo fibers, and animal hair fibers such as wool.

[0053] Furthermore, knitting structures that can be used in weft knitted fabrics include basic plain knitting structures, tuck knitting, float knitting, one rib knitting, lace knitting, plated knitting, jacquard knitting, etc. Knitting structures that can be used in warp knitted fabrics include basic structures such as chain stitch, denbigh stitch, cord stitch, atlas stitch, and insert stitch, as well as modified structures formed by combining these. When various fibers are interknitted with the polyetherester elastic fiber of the present invention, the polyetherester elastic fiber may be knitted over the entire surface, may be knitted at desired intervals, or the polyetherester elastic fiber may be inserted.

[0054] For knitting circular knitted fabrics, knitting machines with a large number of yarn feeders and feeders capable of simultaneously supplying multiple yarns, such as a normal single knit circular knitting machine with a single row of needle beds or a normal double knit circular knitting machine with a double row of needle beds, can be used. The gauge of the knitting machine is usually 5 to 50 gauge, but can be selected appropriately depending on the intended use. For knitting weft knitted fabrics, weft knitting machines such as large weft knitting machines, small weft knitting machines, double-head machines, double-face machines, and jacquard machines, as well as fully fashioned knitting machines such as single-needle machines and double-needle machines can be used. The gauge of the knitting machine is usually 3 to 50 gauge, but can be selected appropriately depending on the intended use.

[0055] In knitting a warp knitted fabric, for example, polyetherester elastic fiber and / or coated polyetherester elastic fiber are wound around a beam in a number appropriate for the desired product in a warping process using a Karl Mayer warper, a River warper, etc. Thereafter, the beam of polyetherester elastic fiber and / or coated polyetherester elastic fiber is placed on a knitting machine described below, and knitted to obtain a desired warp knitted fabric.

[0056] A tricot knitting machine, a Russell knitting machine, or a double Russell knitting machine can be used to knit warp knitted fabrics, and the denier, knitting model, and gauge can be selected appropriately depending on the denier of the yarn used and the intended product. The knitting structure can be the basic knitting structure described above or a variation of the basic knitting structure, such as a combination of these. For a tricot knitting machine, a two-reed half weave, a satin weave, a jacquard weave, or a variation of the basic knitting structure, such as a combination of these weaves, can be used. For a Russell knitting machine or a double Russell knitting machine, a power net weave, a satin net weave, a jacquard weave, or the like can be used. Both tricot knitting machines and Russell knitting machines can also be used to knit with three or more reed weaves. The gauge of the knitting machine is typically 10 to 50 gauge, but can be selected appropriately depending on the intended use.

[0057] Examples of woven fabrics include fabrics obtained by weaving one or more fibers selected from natural fibers such as cotton and hemp, regenerated cellulose fibers such as viscose rayon, cuprammonium rayon (product name: Cupra), and specific cellulose (product name: Tencel), and synthetic fibers such as polyester, polyamide, and PVA, using conventional methods. The yarn arrangement method may be any commonly known method, and may be determined appropriately depending on the structure and density. Conventional looms, such as WJL, AJL, and rapier, can be used for weaving.

[0058] Another embodiment of the present invention is a garment containing the polyetherester elastic fiber as an elastic fiber. The fabric used in the garment of this embodiment can be subjected to a general dyeing process, in which a knitted greige fabric is opened, relaxed, dyed, and then subjected to a finishing set including a resin treatment. If shape fixation is desired before dyeing, presetting can be performed using dry heat at a temperature below the temperature of the polyetherester elastic fiber. The dyeing process can be carried out using a winch dyeing machine, jigger dyeing machine, beam dyeing machine, jet dyeing machine, or other machine, either batchwise or continuously. In addition to immersion dyeing, padding dyeing and printing methods can also be used. Any commonly used dyeing conditions can be used, and the type and concentration of dyeing auxiliaries, dyeing pH, dye bath ratio, dyeing time, and other factors can be appropriately determined taking into account the type of item to be dyed, the processing equipment used, and the dyeing method. For example, when dyeing a blended fabric of polyester fiber and polyether ester elastic fiber, after dyeing with a disperse dye at 135°C or less for 20 minutes to 120 minutes, reduction washing can be carried out as a post-dyeing treatment using a reducing agent such as sodium hydrosulfite or thiourea dioxide in combination with an alkali agent such as an alkali metal hydroxide such as sodium hydroxide, an alkaline earth metal hydroxide such as calcium hydroxide, an alkali metal phosphate such as disodium hydrogen phosphate, or an alkali metal carbonate such as sodium carbonate.

[0059] The clothing of this embodiment encompasses clothing in general, and examples thereof include innerwear such as shorts, shirts, camisoles, slips, bodysuits, briefs, trunks, underwear, girdles, brassieres, spats, belly warmers, pantyhose, tights, socks, and other such innerwear; swimwear, training wear, leotards, ski wear, sportswear for various competitions, outdoor wear, and other such sportswear; outerwear such as T-shirts, jackets, sweaters, vests, pants, skirts, cut-and-sew tops, coats, and jumpers; accessories such as gloves, hats, and scarves; nightwear such as pajamas and gowns; and nursing wear, but are not limited to these.

[0060] The polyether ester elastic fiber of the present embodiment has good recovery and heat resistance, resulting in less thread breakage during dyeing and high stretch recovery, and can be used to produce fabrics and clothing that fit well when worn.

[0061] The present invention will be specifically described with reference to the following examples and comparative examples, but the scope of the present invention is not limited to these examples. First, the evaluation methods used in the following examples will be described.

[0062] <Measurement and Evaluation Methods> <Measurement of Fineness> 50 m of polyetherester elastic fiber was unwound from a polyetherester elastic fiber wound body using a let-off roll while maintaining the elongation rate. The weight (g) of the unwound yarn was measured. The fineness (dtex) of the polyetherester elastic fiber was calculated using the following formula: Fineness (dtex) = Total weight (g) of unwound yarn × 10,000 / 50 (m).

[0063] <Measurement of Small-Angle X-ray Scattering (SAXS)> [Measurement of Phase Separation Index] The test yarn was held at a gripping distance of 10 mm in a metal frame with one side movable so that the yarn length could be freely changed, and this was the state of the test yarn before elongation. Next, one side of the metal frame was moved at a speed of 1000 mm / min so that the test yarn held at 10 mm in the metal frame before elongation was 30 mm, and fixed, and left to stand for 30 minutes. Thereafter, one side of the metal frame was moved at a speed of 1000 mm / min so that the test yarn was 10 mm, and fixed, and left to stand for 30 minutes. If the test yarn slackened due to the influence of elongation and became longer than the initial length of 10 mm, one side of the metal frame was moved and fixed to the minimum length at which slack did not occur. This was the state of the test yarn after elongation and recovery. SAXS was measured under the following conditions before elongation and after elongation recovery, and the phase separation index was quantified as follows. [SAXS Measurement Conditions] The polyether ester elastic fiber was set on the sample stage so that the fiber axis was horizontal. X-rays were irradiated perpendicularly to the fiber, and measurements were performed using SAXS under the following conditions. Measurement device: NANOPIX manufactured by Rigaku Corporation Incident X-ray wavelength λ: 0.154 nm Detector: 2D detector "Hypix-6000" Measurement time: 15 minutes Camera length: 1312 mm Optical system: Point collimation: 1st slit: 1.40 mmφ, guard slit: 0.85 mmφ High Flux Mode Beam stopper: 4 mmφ

[0064] The 12 o'clock direction of the two-dimensional SAXS pattern I(2θ, φ) obtained by the two-dimensional detector is set to 0°, and the azimuth angle φ is defined clockwise, and the following equation (1) is obtained: {In the formula, φ ｓ : -10°, φ ｅ : 10°, θ: Bragg angle}, and the average scattering intensity I of the sector was calculated.

[0065] The obtained sector-shaped average scattering intensity I is calculated using the following formula (2): {In the formula, I ｃ (2θ): Scattering intensity corrected for empty cell, I ｓａｍｐｌｅ (2θ): scattering intensity of the sample, I ｅｍｐｔｙ (2θ): Scattering intensity of empty cell, t ｓａｍｐｌｅ : sample measurement time, t ｅｍｐｔｙ: measurement time of empty cell measurement, T: transmittance, C: instrument constant}, and the one-dimensional scattering intensity I ｃ was calculated.

[0066] In the SAXS profile, the following formula (3): {where θ is the Bragg angle, λ is the wavelength of the incident X-ray}, the absolute value q of the scattering vector is calculated, and then the following equation (4) is used: {In the formula, q １ : 0.20 nm ―１ , q ２ =1.00 nm ―１ Then, the Q value was calculated using the following equation (5): The phase separation index was calculated by the following.

[0067] <Raman spectroscopy measurement> [Measurement of orientation index] The test yarn was held at a gripping distance of 10 mm in a metal frame with one side movable so that the yarn length could be freely changed. Next, one side of the metal frame was moved at a speed of 1000 mm / min so that the test yarn held at 10 mm in the metal frame before elongation became 20 mm, and then fixed and left to stand for 30 minutes. Thereafter, Raman spectroscopy was measured under the following conditions. The Raman spectrum measured by incident linearly polarized light parallel to the fiber axis was taken as the parallel scattering spectrum, and the Raman spectrum measured by rotating the sample 90° and incident linearly polarized light perpendicular to the fiber axis was taken as the perpendicular scattering spectrum. [Raman spectroscopy measurement conditions] The polyether ester elastic fiber was set on a sample stage, and Raman spectroscopy was measured under the following conditions. Measurement equipment: XploRA manufactured by Horiba, Ltd. Excitation wavelength: 532 nm Objective lens: 10x Exposure time: 8 seconds Number of integrations: 4 Diffraction grating: 2400 l / mm Incident polarization: Linear polarization Analyzer: Paranic arrangement

[0068] [Orientation index of hard domain in fiber axis direction] For the parallel scattering spectrum and the perpendicular scattering spectrum, ―１ and 1650 cm ―１ The areas of the Raman spectra and the enclosed areas were calculated, and the area of ​​the parallel scattering spectrum / the area of ​​the perpendicular scattering spectrum was used as an index of the orientation of the hard domain in the fiber axis direction.

[0069] [Orientation index in the fiber axis direction of the phase mixture portion of the soft domain and the hard domain] For the parallel scattering spectrum and the perpendicular scattering spectrum, ―１ and 1810 cm ―１ The distance between the two points is 1720 cm. ―１ A perpendicular line was drawn from the center, and the area enclosed by the Raman spectrum on the low wavenumber side and the straight line and perpendicular line was calculated. The area of ​​the parallel scattering spectrum / the area of ​​the perpendicular scattering spectrum was used as an index of the orientation in the fiber axis direction of the phase mixture of the soft domain and hard domain.

[0070] [Orientation index of soft domain in fiber axis direction] For parallel scattering spectrum and perpendicular scattering spectrum, ―１ and 1810 cm ―１ The distance between the two points is 1720 cm. ―１ A perpendicular line was drawn from the center, and the areas enclosed by the high-wavenumber Raman spectrum, the straight line, and the perpendicular line were calculated. The area of ​​the parallel scattering spectrum / the area of ​​the perpendicular scattering spectrum was used as an index of the orientation of the soft domain in the fiber axis direction.

[0071] <NMR Measurement> [Qualitative and quantitative determination of low molecular weight diol and polymer polyol] A predetermined amount of polyether ester elastic fiber was dried at 80°C under a vacuum of -0.1 MPa for 5 hours, and NMR was measured under the following conditions to qualitatively and quantitatively determine the low molecular weight diol and polymer polyol. [NMR measurement conditions] Measurement device: ECS400 manufactured by JEOL Corporation Measurement nucleus: １ H resonance frequency: 400 MHz Number of accumulations: 256 Measurement temperature: room temperature Solvent: deuterated chloroform Measurement concentration: 1.5 wt% Chemical shift reference: tetramethylsilane (0 ppm)

[0072] <Measurement of reduced viscosity> Approximately 1 g of polyetherester elastic fiber was weighed out, and the entire weight of the weighed fiber was placed in a container containing 50 ml of petroleum ether. After ultrasonic irradiation for 5 minutes, the petroleum ether in the container was discarded and the fiber was dried at 80°C for 5 hours to remove the treatment agent from the polyetherester elastic fiber. 0.3500 g of the polyetherester elastic fiber from which the treatment agent had been removed was dissolved in 40.0000 g of HFIP (1,1,1,3,3,3-hexafluoroisopropyl alcohol) to prepare a 1.39 g / dL solution. The solution's feeding time t (seconds) was measured at a temperature of 25.0°C using an Ubbelohde viscosity tube. At this time, the solvent feeding time t ０ (seconds), the reduced viscosity η ｓｐ / c (dL / g) is expressed by the following formula (6): It was calculated by:

[0073] <Method for Evaluating Elasticity> Using a tensile tester (Orientec Co., Ltd., Model RTG-1210 Tensilon), a 50 mm chuck distance was set at 20°C and a relative humidity of 65%, and a 50 mm long test yarn was subjected to repeated elongation tests at a rate of 500 mm / min from 0% to 200% elongation. The stress during elongation was defined as the S-modulus, and the stress during contraction as the R-modulus. The S-modulus and R-modulus values ​​measured at the third repetition at 150% elongation were used to calculate R / S, the ratio of R-modulus to S-modulus, using the following formula: R / S (%) = S-modulus (cN) measured at the third repetition at 150% elongation / R-modulus (cN) measured at the third repetition at 150% elongation × 100 (%). Five measurements were performed for each test yarn, and a larger average R / S value indicates a polyether ester elastic fiber with better elasticity. In the present invention, the higher the R / S, the better the stretchability of the polyether ester elastic fiber, and it is preferably 63% or more, more preferably 65% ​​or more, more preferably 67% or more, more preferably 69% or more, even more preferably 71% or more, and most preferably 73% or more.

[0074] <Method for Evaluating Stretch Recovery> Using a tensile tester (Orientec Co., Ltd., Model RTG-1210 Tensilon), a 50 mm chuck distance was set at 20°C and a relative humidity of 65%, and a 50 mm sample length test yarn was subjected to repeated elongation tests from 0% to 200% at a rate of 500 mm / min. The stress during elongation was defined as the S-modulus and the stress during contraction as the R-modulus. The recovery rate was calculated from the elongation at which the R-modulus reached 0 (cN) after the third repetition using the following formula: Recovery rate (%) = (200 - elongation at which the R-modulus reached 0 (cN) after the third repetition) (%) / 200 (%) × 100 (%). Five measurements were performed for each test yarn, and the average recovery rate was evaluated as the stretch recovery rate. In the present invention, the higher the recovery rate of the stretch recovery of the polyether ester elastic fiber, the better, and it is preferably 80% or more, more preferably 82% or more, more preferably 84% or more, more preferably 86% or more, even more preferably 88% or more, and most preferably 90% or more.

[0075] <Method for evaluating deterioration of physical properties during dyeing and processing> A test yarn is held at a gripping distance of 50 mm in a metal frame with one side movable so that the yarn length can be freely changed. A mark is made at the gripping distance of 50 mm on the held yarn, and this is the initial length of the test yarn. Next, one side of the metal frame is moved and fixed so that the test yarn held at 50 mm in the metal frame becomes 75 mm, and the metal frame is subjected to hot water treatment at 130°C for 30 minutes using a high-temperature, high-pressure dyeing machine (12LMB-E model, manufactured by Japan Dyeing Machinery Orientec Co., Ltd.). The metal frame is removed from the high-temperature, high-pressure dyeing machine, and one side is moved and fixed so that the test yarn is 50 mm long, and the test yarn is then removed. Due to the influence of heat, the distance between the marks on the removed test yarn at the initial length of 50 mm becomes longer than 50 mm. Thereafter, the test yarn is attached to a tensile tester (Orientec Co., Ltd., RTG-1210 Tensilon) set to a chuck distance of 50 mm at the position marked before heat treatment, and a repeated elongation test is performed from 0% to 200% at a rate of 500 mm / min under conditions of 20°C and 65% relative humidity, and the 200% S-modulus of the first repeated test is measured. The 200% S-modulus after heat treatment relative to the 200% S-modulus of the test yarn not heat treated is called the heat treatment retention rate, and is used as an index of the deterioration of physical properties during the dyeing process. A higher heat treatment retention rate indicates a polyether ester elastic fiber with less deterioration of physical properties during the dyeing process. Measurements of the heat treatment and the 200% R-modulus of the test yarn after heat treatment are performed five times for each test yarn, and the average value is used. In the present invention, the higher the stress retention rate of the polyether ester elastic fiber in the dyeing process, the better the deterioration in physical properties, and it is preferably 89% or more, more preferably 94% or more, more preferably 100% or more, more preferably 104% or more, even more preferably 109% or more, and most preferably 115% or more.

[0076] <Method for evaluating shrinkage during dyeing and finishing> A test yarn is held at a gripping distance of 100 mm in a metal frame with one side movable so that the yarn length can be freely changed. A mark is made at the 100 mm gripping distance on the held yarn, and this is the initial length of the test yarn. Next, one side of the metal frame is moved and fixed so that the test yarn held at 100 mm in the metal frame becomes 50 mm. Using a high-temperature, high-pressure dyeing machine (12LMB-E model, manufactured by Japan Dyeing Machinery Orientec Co., Ltd.), the metal frame is subjected to a hot water treatment at 130°C for 30 minutes. The width of the metal frame is then widened, and the width at the point where the test yarn no longer slackens is recorded and designated as L. The shrinkage rate was calculated using the following formula: shrinkage rate (%) = 100 x (100 - L) / 100. In the present invention, the lower the shrinkage rate of the polyether ester elastic fiber in the dyeing process, the better, and it is preferably 22% or less, more preferably 20% or less, more preferably 18% or less, more preferably 16% or less, even more preferably 14% or less, and most preferably 12% or less.

[0077] <Method for Evaluating Fabric Aesthetics> [Knitting of Gray Machine and Dyeing of Fabric] False-twisted filaments obtained by false-twisting an 84 dtex 36f round cross-section polyester yarn were knitted with polyether ester elastic fiber on a 28G circular knitting machine to obtain a jersey knit fabric composed of 84% polyester and 16% polyurethane elastic fiber. This mixed knit fabric was scoured and relaxed in an open state at 90°C, then pre-set at 140°C and dyed under the following dyeing conditions. [Dyeing Conditions] Dye: C.I. Disperse Blue 167 (benzene azo disperse dye) 7% owf Dispersing and leveling agent: Nikka Sunsalt RM-340 (manufactured by Nicca Chemical Industry Co., Ltd.) 0.5 g / L Acetic acid: 0.5 cc / L Sodium acetate: 1 g / L Bath ratio: 1:20 Dyeing temperature and time: 130°C, 30 minutes. After dyeing was completed, the residual dyeing solution was drained from the dyeing machine, water was charged into the dyeing machine, and the temperature was raised to 90°C. To this was added the following chemicals under the following reduction washing conditions to prepare a reduction washing bath of the following concentrations, and the dyed fabric was subjected to reduction washing at 90°C for 20 minutes. [Reduction Washing Conditions] Thiourea dioxide: 2 g / L Caustic soda: 1 g / L Sunmol RC-700 (non-ionic detergent; manufactured by Nicca Chemical Industry Co., Ltd.): 0.5 g / L Bath ratio: 1:30. After this reduction washing, the residual solution was drained, and the dyed fabric was thoroughly rinsed with warm water and water, and then finished by dry setting at 140°C for 30 seconds. [Evaluation of Fabric Aesthetics] The knitted fabric appearance was evaluated visually by five people according to the following five-point evaluation scale, and the average value was expressed. A rating of 4 to 5 points is considered to be a good knitted fabric and is considered to pass. [Evaluation Criteria] Grade 5: Knitted fabric with very good appearance with no defects in the warp and weft strips Grade 4: Knitted fabric with almost no defects in the warp and weft strips and good appearance Grade 3: Knitted fabric with appearance in which defects in the warp and weft strips are not very noticeable Grade 2: Knitted fabric with appearance in which defects in the warp and weft strips are somewhat noticeable Grade 1: Knitted fabric with appearance in which defects in the warp and weft strips are noticeable [Example 1]

[0078] Chips of a polyetherester elastomer having a reduced viscosity of 4.00 dL / g and containing terephthalic acid, PTMG having a number average molecular weight of 2000, and 1,4-butanediol components in a molar ratio of 1.00:0.81:0.19 were dried in a dehumidifying dryer at a temperature of 80°C until the moisture content reached 100 ppm or less. The polyetherester elastomer resin was then charged into the hopper and melted in the extruder. The resin was metered and pressurized using a gear pump attached to the extruder head, filtered, and extruded at a die temperature of 210°C from a 0.50 mm, one-hole nozzle at a discharge rate of 44 dtex. The length and speed of the cold air were adjusted in a cold air chamber, and cold air was blown perpendicular to the fibers to air-cool the yarn, which was then melt-spun. Three cold air chambers were used, each capable of strictly controlling the temperature and speed of cold air independently: cold air chamber 1, which cooled the area from just below the spinneret to 10 cm below the spinneret; cold air chamber 2, which cooled the area from 10 cm to 50 cm below the spinneret; and cold air chamber 3, which cooled the area from 50 cm to 100 cm below the spinneret, and cold air was blown onto the fiber while strictly controlling the temperature of the yarn at 10 cm, 50 cm, and 100 cm below the spinneret. Thereafter, while applying a treatment agent mainly containing polydimethylsiloxane, the yarn was passed through a first godet roller at a speed of 600 (m / min) and a second godet roller at a speed of 700 (m / min) and wound around a paper tube at a speed of 700 (m / min), to obtain a wound body of polyether ester elastic fiber of 44 dtex / 1 filament. The polyether ester elastic fiber had an R / S of 75%, a recovery rate of 92%, a stress retention rate of 120%, a shrinkage rate of 10%, and an aesthetics grade of 5.

[0079] Examples 2 and 3 Polyether ester elastic fibers were obtained in the same manner as in Example 1, except that the extrusion speed of the polyether ester elastomer resin was adjusted and the total fineness was changed.

[0080] [Examples 4 to 7] Polyether ester elastic fibers were obtained in the same manner as in Example 1, except that the wound body of polyether ester elastic fiber was heated at a temperature adjusted to 60°C or higher and 130°C or lower to adjust the phase separation index.

[0081] [Examples 8 to 14] Polyether ester elastic fibers were obtained in the same manner as in Example 1, except that the yarn temperature at a point 10 cm directly below the spinneret was adjusted by adjusting the yarn temperature and the cold air temperature and speed in the spinning process, and the orientation index in the fiber axis direction of the hard domains was changed.

[0082] [Examples 15 to 19] Polyether ester elastic fibers were obtained in the same manner as in Example 1, except that a polyether ester elastomer resin obtained by polymerizing a low molecular weight diol, 1,4-butanediol, was partially replaced with 1,6-hexanediol and spun.

[0083] [Examples 20 to 23] Polyether ester elastic fibers were obtained in the same manner as in Example 1, except that a part of the PTMG polyol was replaced with polyethylene glycol (PEG) having a number average molecular weight of 2,000, and a polyether ester elastomer resin was polymerized and spun.

[0084] [Examples 24 to 29] Polyether ester elastic fibers were obtained in the same manner as in Example 1, except that the reduced viscosity of the polyether ester elastic fibers was adjusted using polyether ester elastomer resins whose polymerization degrees were adjusted by changing the polymerization temperature and time.

[0085] [Examples 30 to 37] Polyether ester elastic fibers were obtained in the same manner as in Example 1, except that the temperature and speed of the cold air in the region from 10 cm to 50 cm below the spinneret were changed in the spinning process, and the orientation index in the fiber axis direction of the phase mixture portion of the soft domain and the hard domain, measured by Raman spectroscopy, was changed.

[0086] [Examples 38 to 45] Polyether ester elastic fibers were obtained in the same manner as in Example 1, except that the temperature and speed of the cold air from 50 cm to 100 cm below the spinneret were changed in the spinning process, and the orientation index of the soft domain in the fiber axis direction, measured by Raman spectroscopy, was changed.

[0087] Comparative Examples 1 and 2 Polyether ester elastic fibers were obtained in the same manner as in Example 1, except that the extrusion speed of the polyether ester elastomer resin and the winding speed of the winder were adjusted and the total fineness was changed.

[0088] [Comparative Examples 3 and 4] Polyether ester elastic fiber was obtained in the same manner as in Example 1, except that the wound body of polyether ester elastic fiber was heated at a temperature adjusted to 40°C or higher and 150°C or lower to adjust the phase separation index.

[0089] Comparative Example 5 A polyether ester elastic fiber was obtained in the same manner as in Example 1, except that the yarn temperature at points 10 cm, 50 cm, and 100 cm directly below the spinneret was controlled by adjusting the yarn temperature and the cold air temperature and speed in the spinning process, and the orientation index in the fiber axis direction of the hard domains was changed.

[0090] Comparative Examples 6 and 7 Polyetherester elastic fibers were obtained in the same manner as in Example 1, except that the extrusion speed of the polyetherester elastomer resin was adjusted and the winding speed of the winder was changed to 3000 m / min or more and 5000 m / min or less.

[0091] The production conditions and the measurement results of the various properties of the obtained polyether ester elastic fibers in the above examples and comparative examples are shown in Tables 1 to 6 below.

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098] The polyether ester elastic fiber and a wound body of the fiber of the present invention have good elasticity and elastic recovery, and can sufficiently suppress a decrease in tensile stress and the occurrence of wrinkles in the fabric even after dyeing and finishing processes, and have good aesthetic appearance as a fabric. Furthermore, the fabric and clothing of the present invention are resistant to wrinkles in dyeing and finishing processes and have a good sense of power and fit when worn. Therefore, the present invention can be suitably used as an elastic fiber in various fields, including clothing.

Claims

1. A polyether ester elastic fiber having a total fineness of 5 dtex or more and 80 dtex or less, a phase separation index of 0.20 or more and 0.65 or less as measured by a small-angle X-ray scattering device, and an orientation index of the hard domain in the fiber axis direction of 10.00 or less as measured by Raman spectroscopy.

2. The polyether ester elastic fiber according to claim 1, wherein 80 mol % or more of the low molecular weight diol units constituting the polyether ester are selected from the group consisting of 1,4-butanediol, 1,6-hexanediol, 1,3-propanediol, and ethylene glycol, and 50 mol % or more of the polymer polyol units are PTMG or a copolymer diol consisting of tetrahydrofuran (THF) and neopentyl glycol.

3. The polyether ester elastic fiber according to claim 1 or 2, having a reduced viscosity of 2.00 dL / g or more and 6.00 dL / g or less.

4. A polyether ester elastic fiber according to claim 1 or 2, wherein the orientation index in the fiber axis direction of the phase mixture portion of the soft domain and the hard domain measured by Raman spectroscopy is 2.50 or more and 5.00 or less.

5. A polyether ester elastic fiber according to claim 1 or 2, wherein the orientation index of the soft domain in the fiber axis direction measured by Raman spectroscopy is 1.50 or more and 4.00 or less.

6. A wound body of the polyether ester elastic fiber according to claim 1 or 2.

7. A fabric comprising the polyether ester elastic fiber according to claim 1 or 2.

8. Clothing comprising the polyether ester elastic fiber according to claim 1 or 2.

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