curled fiber

Abstract

The coiled fiber related to this invention is a composite fiber composed of two polymers, polymer A and polymer B. It has a coiled shape in the fiber axis direction, the ratio of the coil diameter Dc to the single fiber diameter df, Dc / df, is 2.0 or more and 20.0 or less, the number of coil pitches is 1.0 or more / mm and 10.0 or less, polymer A is completely covered by polymer B in the fiber cross-section, and the moisture absorption and release parameter ΔMR is 2.0% or more.

Description

[Technical Field]

[0001] This invention relates to hygroscopic curled fibers. [Previous Technology]

[0002] Synthetic fibers composed of thermoplastic resins such as polyamide and polyester are widely used in clothing and industrial applications due to their excellent mechanical properties, chemical resistance, and heat resistance. Polyamide fibers, such as polydecylamide and polyhexamethylene hexamethylenediamide, possess unique softness, high tensile strength, excellent color development during dyeing, high heat resistance, and excellent moisture absorption. Polyester fibers, such as polyethylene terephthalate, have characteristic tensile strength, toughness, a gentle hand feel, minimal change in properties when wet, and excellent quick-drying properties, wrinkle resistance, and dimensional stability. These synthetic fibers utilize their superior properties and are widely used in clothing applications, such as in underwear and sportswear.

[0003] As everyone aspires to a comfortable life, the demands on fiber materials are also increasing. Therefore, the refinement of fiber materials used to achieve comfort is in full swing. Generally, the comfort of clothing varies depending on the environment and atmosphere in which the material is used. Among these, maintaining a suitable environment between the clothing and the skin, that is, the space within the clothing, is a crucial factor directly related to comfort.

[0004] The temperature and humidity inside clothing are limited, which contributes to human comfort, and regulating these to an appropriate level is crucial. In particular, to suppress the stuffiness and stickiness that easily occur in hot and humid summer environments, it is highly desirable to imbue clothing materials with moisture-wicking properties. However, compared to natural fibers such as cotton, polyamide fibers are not considered to have sufficient moisture-wicking properties, and hydrophobic polyester fibers, depending on their weave, can sometimes compromise comfort due to stuffiness and stickiness.

[0005] Therefore, the proposal is to make composite fibers with hygroscopic polymers to improve hygroscopicity. For example, the island composite fiber proposed in Patent Document 1 imparts hygroscopicity to the fiber by using hygroscopic polymers in the island portion, and controls the thickness of the polyester in the sea portion, which exists in the outermost layer of the fiber cross-section, to suppress the polyester in the sea portion from breaking during hot water treatment.

[0006] The core-sheath composite fiber proposed in Patent Document 2 is a core-sheath composite fiber formed by a core and a sheath, wherein the core is not exposed on the fiber surface. The core is a polyether block amide copolymer with 6-nylon as the hard segment, and the sheath is 6-nylon resin.

[0007] Furthermore, proposed methods to suppress stuffiness inside clothing include: using fibers with a curling structure to create woven fabrics, changing the curling shape during moisture absorption and release to adjust the breathability of the original fabric. The stress generated by the volume expansion of the hygroscopic polymer during moisture absorption is dispersed by the elongation of the fibers along the fiber axis, thereby improving the durability of the hygroscopic synthetic fibers.

[0008] For example, the composite fiber proposed in Patent Document 3 has a coiled structure consisting of a polyamide component and a polyester component of an aqueous swelling polyether ester polymer bonded side to side.

[0009] Furthermore, the water-repellent woven fabric that improves breathability when absorbing moisture proposed in Patent Document 4 contains a composite fiber with a shrinkage structure in which polyester and polyamide components are bonded side to side and the shrinkage rate is different when dry and when wet.

[0010] Furthermore, methods for suppressing stuffiness inside clothing also include utilizing the shrinkage structure of fibers to impart water absorption. For example, the moisture-absorbing and releasing shrinkage processed yarn proposed in Patent Document 5 is composed of moisture-absorbing and releasing components and fiber-forming polymers, and is a shrinkage-type synthetic fiber. [Prior Art Documents] [Patent Documents]

[0011] [Patent Document 1] International Publication No. 2018 / 012318 [Patent Document 2] International Publication No. 2014 / 10709 [Patent Document 3] Japanese Patent Application Publication No. 2009-114581 [Patent Document 4] Japanese Patent Application Publication No. 2006-97176 [Patent Document 5] Japanese Patent Application Publication No. Hei 11-279871 [Summary of the Invention]

[0012] (The problem that the invention aims to solve)

[0013] The composite fiber systems described in Patent Documents 1 and 2 have high moisture absorption properties. On the other hand, when absorbing moisture, the hygroscopic polymers in the island and core regions swell in volume. Therefore, when these fibers are processed into yarns and the fiber cross-section changes significantly, stress generated due to the volume swelling of the hygroscopic polymers can cause cracks or other fractures on the fiber surface, peeling of polymers between the sea and island regions, or between the sheath and core regions, and voids in the hygroscopic polymers of the island and core regions.

[0014] Accordingly, when the fiber surface appears cracking and other fractures, the sea part and the island part or the sheath part and the core part of the polymer peeling from each other, uneven dyeing, hair balls, etc. will occur and the quality of the woven products will be reduced. Also, there are cases of reduced hygroscopicity due to the dissolution of hygroscopic polymers. Furthermore, there are cases where the fiber diameter increases due to the volume expansion of the hygroscopic polymer, resulting in a decrease in the voids between the fibers constituting the fabric with each other, thereby reducing aeration, damage and comfort.

[0015] The side-to-side type composite fibers revealed in Patent Literature 3 and Patent Literature 4 are classified as merely fitted constructions. Therefore, there are cases of low curling performance, insufficient changes in fiber morphology during moisture absorption, and cases of increased fiber diameter due to volume expansion of hygroscopic polymers, resulting in reduced voids between the fibers constituting the fabric, thus reduced ventilation, damage and comfort. Also, because it belongs to the structure of a mere fit, there is a possibility of peeling at the interface due to friction and impact, partial white stripe-like whitening phenomenon, puffing and other reduced fabric quality. Also, because the hygroscopic polymers are exposed on the fiber surface, the hygroscopic polymers are easily dissolved, and practical use has the subject of reduced hygroscopicity due to repeated use.

[0016] The curling-processed yarns described in Patent Literature 5 are endowed with curling by means of thread processing such as dummy-stitch processing, squeeze-in curling-processing, or fluid-extrusion-in-rolling-processing utilizing heated fluids. Therefore, there are cases of low curling properties and insufficient changes in fiber morphology.

[0017] The invention is completed to solve the above problems, the topic lies in providing: excellent hygroscopicity, can inhibit fractures such as cracking on the fiber surface due to moisture absorption, peeling of polymers from each other between sea and island or sheath and core, and reduced quality due to voids with hygroscopic polymers in the island and core.

[0018] The inventors, through in-depth research, conceived of a method to improve the durability of hygroscopic synthetic fibers by dispersing the stress generated by the volume expansion of hygroscopic polymers during moisture absorption through the elongation of the fibers as they curl towards the fiber axis. Specifically, this invention provides a curled fiber that suppresses defects generated on or within the fiber surface by dispersing the stress generated by the volume expansion of the fibers during moisture absorption through the elongation of the curl imparted to the composite fiber. Furthermore, this invention also provides a curled fiber that, when used in woven fabrics, suppresses the decrease in breathability of the fabric by elongating during moisture absorption and / or water absorption, ensuring comfort even during sweating and preventing a decrease in moisture absorption due to repeated use. (Technical means to solve the problem)

[0019] The present invention has the following configuration in order to solve the above-mentioned problems. (1) A coiled fiber, which is a composite fiber composed of two polymers, such as polymer A and polymer B, having a coiled shape in the fiber axis direction, wherein the ratio of the coil diameter Dc to the single fiber diameter df, Dc / df, is 2.0 or more and 20.0 or less, the number of coil pitches is 1.0 or more and 10.0 or less, polymer A is completely covered by polymer B in the fiber cross-section, and the moisture absorption / desorption parameter ΔMR is 2.0% or more. (2) The coiled fiber as described in (1) above, wherein, of the two polymers, polymer A has higher hygroscopicity. (3) The coiled fiber as described in (1) above, wherein the two polymers have the same type of bond in the main skeleton constituting the repeating unit of each of the two polymers. (4) A fiber product using the coiled fiber described in any one of (1) to (3) above. (Effects compared to prior art)

[0020] According to the present invention, a curled fiber with excellent moisture absorption can be obtained. Furthermore, by dispersing the stress generated when the fiber volume swells during moisture absorption through the elongation of the curl imparted to the composite fiber, a curled fiber that suppresses defects generated on the fiber surface or inside the fiber can be obtained. Moreover, when the curled fiber of the present invention is made into woven fabrics, etc., the fabric's breathability is suppressed by the elongation during moisture absorption and / or water absorption, ensuring comfort even during sweating. Furthermore, it retains excellent moisture absorption even after repeated use, and also possesses the stretchability necessary for movement control, making it particularly suitable for clothing applications where comfort is emphasized.

Implementation Method

[0022] Hereinafter, the present invention will be described in detail. The following description is an example of the present invention, but the present invention is not limited thereto. In addition, in this specification, the reference tilde "~" indicates a range including the numbers stated before and after it. Also, in this specification, "mass" and "weight" are synonymous.

[0023] The crimped fiber of this embodiment is a composite fiber composed of two polymers, and has excellent moisture absorption properties with a moisture absorption / release parameter ΔMR of 2.0% or more. Therefore, a fiber structure with excellent wearing comfort can be obtained when used as a cooling material.

[0024] The crimped fiber of this embodiment is as described above, and its moisture absorption and release parameter ΔMR reaches 2.0% or more. Here, ΔMR is the difference in moisture absorption rate of the fiber under high temperature and high humidity conditions represented by 30°C and 90% relative humidity, and under standard temperature and humidity conditions represented by 20°C and 65% relative humidity. The higher the ΔMR, the higher the moisture absorption of the fiber. If the ΔMR of the crimped fiber of this embodiment reaches 2.0% or more, the garment made of the crimped fiber of this embodiment will have less stuffiness and improved wearing comfort. A more desirable ΔMR range is 4.0% or more. In this case, because more moisture can be retained in the fiber, in addition to suppressing stuffiness, it can also exhibit excellent antistatic properties. An exceptionally desirable ΔMR range is 6.0% or more. Because even more moisture can be retained in the fiber, when the fabric is made, it can quickly absorb water vapor, so that the wearer can feel a cool sensation upon contact. This characteristic is effective from the perspective of wearing comfort. If ΔMR can further improve the moisture absorption performance by more than 8.0%, then even in the high temperature and high humidity environment of summer, it can still suppress stuffiness and stickiness, which can be listed as an excellent range.

[0025] There is no particular upper limit to the ΔMR range. The level achievable by this embodiment is around 17%, which is the practical upper limit. That is, ΔMR can also be below 17%. Furthermore, the crimped fiber system of this embodiment still meets the above-mentioned ΔMR range even before and after hot water treatment such as dyeing.

[0026] A hygroscopic fiber draws in water molecules using physical adsorption, and / or the interaction formed between functional groups and water molecules in the molecular configuration of the fiber constituent components. In particular, in cases with high hygroscopicity, because most water molecules are inhaled into the fibers, there is thus a greater volume expansion. Generally, hygroscopic fibers are not prone to elongation deformation in the fiber axis direction when volume expansion due to moisture absorption, and thus expansion deformation occurs mainly towards the vertical direction of the fiber axis, that is, the area expansion direction of the fiber cross-section. However, in fibers constituted by polymers with rigid aromatic rings in the main skeleton of, for example, aromatic polyester-like constitutive repeat units, the fibers are not easily deformed, and the stresses generated during volume expansion due to moisture absorption are not completely dispersed, resulting in cracks on the fiber surface. Furthermore, in fibers composed of flexible polymers such as aliphatic polyamide and polyolefins with lower glass transition points, the deformation produced by volume expansion due to moisture absorption is utilized, and there are cases where the polymers are peeled off from each other between the sea part and the island, or the sheath and the core, or the polymers constituting the island and the core.

[0027] Here, the coiled fiber of the present embodiment that suppresses the disadvantages that arise on the fiber surface or inside the fiber due to volume expansion during moisture absorption focuses on having a coil-like coiled morphology in the fiber axis direction. The so-called “coil-like coiled form” here is exemplified by the three-dimensional helical coiling presented by the poor shrinkage of the two polymers resulting from the use of heat treatment, which causes the single fibers constituting the coiled fibers to bend;

[0028] Because the coiled fibers of the present embodiment have a coil spring shape, twisting occurs in the direction of the fiber axis of the single fiber. Therefore, when the volume expands due to moisture absorption, the torsion will be used as the base point, and the force on the single fiber towards the addition can be elongated deformation towards the fiber axis. By means of this elongation deformation, the expansion deformation towards the area expansion of the fiber cross-section will be reduced, which can further improve the durability of the coiled fiber. Furthermore, when used as a fibrous construct such as fabric, by elongating deformation toward the fiber axis of the coiled fiber when absorbing moisture and / or when absorbing water, the ventilation of the original fabric can be maintained, showing the comfort of wearing. Furthermore, upon humidification and / or drying, it returns to its shape before moisture absorption and / or absorption due to the force acting on the single fiber in the reverse direction, and thus the same deformation can be carried out even after repeated use. Furthermore, because the recourse to forces from the outside can also undergo elongation deformation toward the fiber axis of the coiled fiber, fiber constructs such as cloth can be manifested for the necessary stretching properties to follow the wearer's movements.

[0029] As an indicator determining the coiled shape of the coiled fiber in this embodiment, the important aspect of the coiled fiber in this embodiment is controlling the ratio Dc / df of the coil diameter Dc to the single fiber diameter df. The larger Dc / df is, the softer the coiled shape is, and the easier it is to stretch and deform. That is, the stress generated by the volume expansion during moisture absorption can be dispersed by the elongation of the coil. Furthermore, by using the soft coiled shape, when forming fabrics, knitted fabrics, etc., appropriate stretchability and other functions can be exhibited, and a soft hand feel with a rebound and fluffy feel can be obtained.

[0030] On the other hand, the smaller the Dc / df ratio, the stiffer the coiled shape becomes, and the less likely it is to stretch or deform. However, because the shape stability of the coiled shape is improved, it can maintain its coiled shape even with repeated moisture absorption and release. Furthermore, because the shape of the coiled shape is stable, when making fabric, the twisting of the coiled fibers and the entanglement of the coiled shapes between adjacent fibers create gaps between the fibers. Utilizing the capillary phenomenon of these microfiber gaps, water absorption is achieved. Combined with the moisture absorption properties of the coiled fibers in this embodiment, a fiber structure with excellent wearing comfort as a cooling material can be obtained. In addition, because the shape of the coiled shape is stable, it can also exhibit responsiveness to the wearer's movements.

[0031] Based on these circumstances and through in-depth research, the ratio of the coil diameter Dc to the single fiber diameter df in the curled fiber system of this embodiment, Dc / df, is 2.0 or more and 20.0 or less. By setting Dc / df to 2.0 or more, the coiled curled form is easy to stretch and deform, and the stress generated by the volume expansion during moisture absorption can be dispersed by the stretching of the curl. Furthermore, when the curled fiber of this embodiment is made into fabrics, knitted fabrics, or other textiles, it exhibits appropriate stretchability and can achieve a soft hand feel with a rebound and fluffy texture. On the other hand, by setting Dc / df to 20.0 or less, the coiled curled form is stable, and the curled form can be maintained even with repeated moisture absorption and release. In addition, by utilizing the capillary phenomenon of the fine interfiber gaps manifested by the coiled curled form, water absorption and other functions are exhibited, thus obtaining a fiber structure with excellent wearing comfort as a cooling material. The optimal DC / DC ratio is 4.0 or higher and below 18.0, while the better ratio is 6.0 or higher and below 16.0.

[0032] The "coil diameter Dc" in this embodiment refers to the value measured from the side (the direction perpendicular to the fiber axis) of a single fiber separated from the coiled fiber of this embodiment, and from the ridge and valley observed alternately in the fiber width direction 3 as illustrated in Figure 1.

[0033] Specifically, the fiber sample to be evaluated is formed into a 10m skein using a spinning machine or similar device. A load of 0.2 mg / d is applied, and the sample is immersed in boiling water at 98°C or higher for 15 minutes. After the boiled water-treated yarn is thoroughly dried by air drying, a load of 2 mg / d is applied for at least 30 seconds, and then marks are made at random points on the yarn bundle with a distance of 3 cm between two points. Then, individual fibers are separated from the yarn bundle in a manner that does not cause plastic deformation, and the pre-marked intervals are adjusted to the original 3 cm and fixed on a glass plate. The sample is then imaged using a microscope (e.g., a digital microscope manufactured by KEYENCE) at a magnification that allows observation of 5 to 10 curled ridges. In the captured image (Figure 1), the vertices of any adjacent ridges along the fiber width direction 3 are designated as M1 and M2, and the valley between M1 and M2 is designated as V. The shortest distance (μm) between the connecting line of M1 and M2 and V (symbol 1 in Figure 1) is measured to two decimal places. The same operation is performed on randomly selected single fibers. By repeating this operation, the shortest distance is measured in groups of 50. The simple mean of the 50 shortest distances is calculated, and the value rounded to two decimal places is set as the coil diameter Dc (μm).

[0034] Furthermore, the "single fiber diameter df" in this embodiment is a value calculated according to the following method. That is, the fiber sample is encapsulated with an encapsulating agent such as epoxy resin, and the cross-section of the fiber in the direction perpendicular to the fiber axis is photographed using a scanning electron microscope (e.g., a HITACHI scanning electron microscope (SEM)) at a magnification that allows observation of more than 10 single fibers. Then, the diameter of a single fiber randomly sampled from the same image (e.g., element symbol 8 in Figure 2(b)) is measured to two decimal places in μm units. The simple average of the results of performing this operation on 10 randomly sampled single fibers is calculated, and the value rounded to two decimal places is set as the single fiber diameter df (μm). Here, when the cross-section of the fiber in the direction perpendicular to the fiber axis is not a perfect circle, the obtained image is analyzed using software such as WinROOF manufactured by Mitani Corporation to measure the area, and the value is obtained by converting it to a circle with the same area.

[0035] The coiled fiber system of this embodiment has a coiled shape along the fiber axis, and the number of coil pitches is 1.0 or more per mm and 10.0 or less per mm. The "number of coil pitches" here refers to the factor that determines the elongation deformation of the coiled shape. That is, by setting the number of coil pitches to 1.0 or more per mm, a sufficient number of coiled shapes exist per unit length, thus generating the necessary elongation deformation to disperse the stress generated by the volume expansion during moisture absorption. Furthermore, because a sufficient number of coiled shapes exist, fine inter-fiber gaps appear when the fiber structure is made into fabric or similar material, resulting in functional properties such as water absorption. Moreover, by setting the number of coil pitches to 10.0 or less per mm, the elongation deformation at a certain stress is increased, and when the fiber structure is made into fabric or similar material, the elongation deformation of the coiled fibers caused by moisture absorption and / or water absorption can maintain air permeability. In addition, the fiber structure exhibits moderate stretch, making it a material with excellent wearing comfort. The preferred coil pitch is 1.5 coils / mm or higher and 9.0 coils / mm or lower, and even better is 2.0 coils / mm or higher and 8.0 coils / mm or lower.

[0036] Furthermore, in the coiled fiber of this embodiment, the number of coil pitches is calculated using the following method. Using the image taken when measuring the coil diameter Dc, the distance (mm) between the vertices M1 and M2 of any adjacent ridges in the coiled shape (element symbol 2 in Figure 1) is calculated to two decimal places. This operation is performed at any three locations for each single fiber, and for 10 different single fibers. The reciprocal of the simple numerical average of these measurement results is calculated, and the value rounded to two decimal places is taken as the number of coil pitches (pitches / mm).

[0037] The cross-section of the crimped fiber system in this embodiment is composed of two polymers. The term "polymer" here is preferably used to refer to a fiber-forming thermoplastic polymer.

[0038] Because the crimped fiber of this embodiment has excellent moisture absorption, it can be used, for example, as an underwear fiber that is close to the wearer's skin in clothing applications. In the case of underwear, other clothes made of other materials are also worn over it. In such cases of overlapping, static electricity is generated due to friction between the underwear and other clothes, which may impair the wearer's comfort. Therefore, the crimped fiber of this embodiment preferably has a half-life of less than 10 seconds at a temperature of 20°C and a relative humidity of 40%, as measured by JIS L1094 (Test Method for Electrostatic Properties of Fabrics and Knitted Fabrics, 2014) Method A (Half-life Determination Method).

[0039] The so-called "half-life" refers to the time it takes for the voltage on the original fabric sample to decrease to 50% of the initial voltage after a specific voltage is applied. It is an indicator of the ease with which static electricity generated on the original fabric can escape, i.e., the destatic property.

[0040] If the half-life at 20°C and 40% relative humidity is less than 10 seconds, the curled fiber of this embodiment has good antistatic properties. When worn in layers, static electricity generated by friction is easily dissipated, thus allowing for comfortable wearing of clothing made of the curled fiber of this embodiment. The half-life at 20°C and 40% relative humidity is preferably less than 5 seconds.

[0041] The key feature of the crimped fiber in this embodiment is that the fiber cross-section has a composite form composed of two polymers, polymer A and polymer B, and polymer A is completely covered by polymer B. Here, "polymer A is completely covered by polymer B" means that in the fiber cross-section, polymer A is not exposed on the fiber surface of the crimped fiber, but is formed continuously by polymer B.

[0042] Figure 2(a) shows an example of the cross-section of the crimped fiber of this embodiment. In Figure 2(a), the horizontal shaded line indicates polymer component 5, which is polymer B, and the 30-degree shaded line (upper right line) indicates polymer component 4, which is polymer A. As shown in Figure 2(a), polymer A is completely covered by polymer B and is not exposed on the surface of the crimped fiber. By completely covering polymer A with polymer B, even if the fiber deforms due to volume expansion during moisture absorption, the durability at the interface between the two polymers can still be improved. Furthermore, even if friction or impact is applied to the fiber or fabric, the interface between the two polymers is not easily peeled off, thus suppressing whitening, pilling, etc., and maintaining good fabric quality. In addition, even components that are exposed on the surface of the composite fiber in a simple bonding structure and become a cause of defects, such as high molecular weight polymers, high elasticity polymers, and polymers with low heat resistance or abrasion resistance, can still be used as one of the components of the composite fiber.

[0043] Preferred polymer systems for achieving the intended purpose include, for example, aromatic polyesters such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate; aliphatic polyesters such as polylactic acid; aliphatic polyamines such as polydecylamine and polyhexamethylene hexamethylenediamine; semi-aromatic polyamines such as polyhexamethylene terephthalamide; thermoplastic elastomers such as thermoplastic polyurethane; and polyolefins such as polypropylene. Generally, from the viewpoint of mechanical properties, heat resistance, and manufacturability, aromatic polyesters or aliphatic polyamines are preferred.

[0044] The above-mentioned aromatic polyester is a high molecular weight polymer in which repeating units are linked by ester bonds on a main chain composed of a combination of aromatic dicarboxylic acids and aliphatic diols, aliphatic dicarboxylic acids and aromatic diols, or aromatic dicarboxylic acids and aromatic diols. Among these, aromatic polyesters composed of aromatic dicarboxylic acids and aliphatic diols are preferred. Examples of the aromatic dicarboxylic acid system include: p-phthalic acid, isophthalic acid, phthalic acid, sodium isophthalate-5-sulfonate, isophthalate-5-sulfon(tetraalkyl)phosphonium, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, etc., but are not limited to these. Examples of the aliphatic diol system include: ethylene glycol, 1,3-propanediol, 1,4-butanediol, hexanediol, cyclohexanediol, diethylene glycol, hexanediol, neopentyl glycol, etc., but are not limited to these.

[0045] When aromatic polyester is used in the shrink fiber of this embodiment, the rigidity of the fiber properties is improved, so even if the shrink fiber is repeatedly stretched and deformed due to moisture absorption and release, the shrink shape can still be maintained. Furthermore, when made into fabric, a tensile and resilient hand feel can be obtained. Also, generally because aromatic polyester does not have functional groups that form strong interactions with water molecules in the polymer structure, shrink fibers and fabrics with excellent quick-drying properties can be obtained.

[0046] Furthermore, the aforementioned aliphatic polyamides are high molecular weight products having so-called hydrocarbon groups linked to repeating units in the main chain via amide bonds. They are generally synthesized using a condensation polymerization reaction with aminocarboxylic acids or cyclic amides as raw materials, or a condensation polymerization reaction with dicarboxylic acids and diamines as raw materials. There are no particular limitations on the polyamide; examples include: polydecylamine, polyundecylamine, polylaurylamine, or polyhexamethylene hexamethylenediamine, polyhexamethylene decanediaamine, polyhexamethylene dodecanediamine, etc.

[0047] When aliphatic polyamide is used in the crimped fiber of this embodiment, the hygroscopicity is achieved by utilizing the amide bonds in the repeating units or the amine groups bonded to the ends of the polymer structure, thus obtaining crimped fibers with very high hygroscopicity. Furthermore, since aliphatic polyamides generally have a low glass transition point due to their polymer properties and are therefore flexible, the crimped fiber easily elongates and deforms due to moisture absorption and / or water absorption, further enhancing the durability of the crimped fiber of this embodiment. Moreover, when made into fabric, the very high hygroscopicity provides a cool feel upon contact. In addition, the low glass transition point results in a softer hand feel.

[0048] The manufacturing method of the polymer in this embodiment is not limited. If a monomer including the raw materials used in the manufacturing process is made, the monomer can also be synthesized using general condensation polymerization, addition polymerization, etc. Examples of monomer systems include: petroleum-derived monomers, biomass-derived monomers, mixtures of petroleum-derived monomers and biomass-derived monomers, and recycled monomers obtained by chemical recycling of polymers, but are not limited to these. Alternatively, the polymer can also be manufactured from waste plastics and other waste materials using material recycling methods. Furthermore, in the polymer of this embodiment, in addition to the main component, a second component and a third component can also be copolymerized or mixed without departing from the scope of the present invention.

[0049] The crimped fiber of this embodiment, as described above, has a moisture absorption / desorption parameter ΔMR, which is an indicator of hygroscopicity, of 2.0% or higher. Examples of methods for setting the ΔMR of the crimped fiber of this embodiment within the above range include: adding a hygroscopic compound, preparing a polymer with high hygroscopicity (hereinafter also referred to as a "hygroscopic polymer"), and treating the polymer molecules on the fiber surface with ozone or the like to generate hygroscopic functional groups. Among these methods, if it is desired to obtain a crimped fiber with excellent hygroscopicity, it is preferable to use a hygroscopic polymer.

[0050] Examples of preferred hygroscopic polymers used in the crimped fibers of this embodiment include, for example, polyether esters, polyether amides, polyether amides, polyamides, thermoplastic cellulose derivatives, polyvinylpyrrolidone, etc. Among these, from the viewpoint of excellent stability during melt molding and high target hygroscopicity, preferred copolymers are polyether esters, polyether amides, and polyether amides containing polyethers.

[0051] The term "polyether ester" refers to a block copolymer with ester and ether bonds in its polymer structure. Specifically, it is a block copolymer polymer obtained by polycondensation reaction of a polyester forming component composed of dicarboxylic acid and diol with a polyalkylene glycol component.

[0052] The combination of the polyester forming component and the polyalkylene glycol component is not limited. A preferred example, from the viewpoint of the heat resistance of the hygroscopic polymer, is a polyether ester copolymerized with polyethylene glycol, using an aromatic polyester composed of an aromatic dicarboxylic acid and an aliphatic diol as the polyester forming component. From the viewpoint of inhibiting the dissolution of the hygroscopic polymer in hot water, a polyether ester composed of polybutylene terephthalate with excellent crystallinity and polyethylene glycol is more preferred.

[0053] Furthermore, the so-called "polyether amide" is a block copolymer with amide bonds and ether bonds in its polymer structure. Specifically, for example, it is a block copolymer polymer obtained by polycondensation reaction of one or more polyamide-forming components selected from amide, aminocarboxylic acid, and salts of diamine and dicarboxylic acid with polyalkylene glycol components.

[0054] There are no particular limitations on the combination of the polyamide-forming component and the polyalkylene glycol component. In a preferred embodiment, examples of polyamide-forming components include: β-caprolactam and other lactamines; ω-aminocarboxylic acids such as aminohexanoic acid; and nylon salts of diamine-dicarboxylic acids that are precursors, such as polyhexamethylene hexamethylenediamine and polyhexamethylene decanedialiamine. Examples of polyalkylene glycol components include: polyethylene glycol. From the viewpoint of the heat resistance, fiber-forming properties, and moisture absorption of hygroscopic polymers, it is more preferable to use β-caprolactam as the polyamide-forming component and copolymerize it with polyethylene glycol to form a polyether amide.

[0055] Furthermore, the so-called "polyether ester amide" is a block copolymer whose polymer structure contains ether bonds, ester bonds, and amide bonds. Specifically, it is a block copolymer polymer obtained by polycondensation reaction of one or more polyamide-forming components selected from amide, aminocarboxylic acid, and salts of diamine and dicarboxylic acid, and a polyether ester component composed of dicarboxylic acid and polyepoxide diol.

[0056] The combination of the polyamide-forming component and the polyether ester component is not limited. In a preferred example, the polyamide-forming component can be exemplified by the polyether amide described above. Furthermore, the polyalkylene glycol component constituting the polyether ester component can be, from a hygroscopic point of view, polyethylene glycol, and as a dicarboxylic acid, adipic acid, sebacic acid, dodecanoic acid, p-phthalic acid, and isophthalic acid.

[0057] In the hygroscopic polymer of the curled fiber of this embodiment, without departing from the scope of the present invention, in addition to the main component, a second component and a third component may be copolymerized or mixed. The amount of copolymerization is relative to the total amount of monomers, and the amount of monomers of the copolymerized component is preferably less than 10 mol%.

[0058] As described above, the hygroscopic polymer has a high affinity for water and is easily dissolved when it comes into contact with water or hot water during dyeing. If the hygroscopic polymer dissolves outside the fiber, the hygroscopicity of the fiber will decrease. Therefore, in the crimped fiber of this embodiment, the hygroscopic polymer described above is preferably completely covered by polymer B exposed on the fiber surface in the fiber cross-section, that is, it is preferable to use polymer A as the hygroscopic polymer. By preventing the hygroscopic polymer from being exposed on the fiber surface, the situation where the hygroscopic polymer dissolves outside the fiber upon contact with hot water can be suppressed. Furthermore, the crimped fiber of this embodiment significantly improves the durability of the crimped fiber by utilizing the coil-like crimped shape in the fiber axis direction, and crimped fibers with excellent hygroscopicity can be obtained.

[0059] There are no particular limitations on the combination of the two polymers constituting the crimped fiber of this embodiment, but it is best to select a combination of polymers with high affinity and easy solubility. By setting it as a combination of polymers with high affinity, the molecular chain entanglement at the polymer interface is promoted, thereby suppressing interfacial delamination between the two polymers. In addition, it also improves the fiber's conformability during deformation, so that deformation strain does not accumulate on the fiber surface or inside the fiber, thereby further improving the durability of the crimped fiber.

[0060] As a combination of such polymers, it is preferable that the main backbones of the repeating units constituting the two polymers each have the same type of bond. Examples of "bonds" include, for instance, amide bonds, ester bonds, ether bonds, urea bonds, and amine ester bonds. That is, having the same type of bond in the main backbones of the repeating units constituting the two polymers means, for example, if the repeating units of polymer A have amide bonds, then the repeating units of polymer B also have amide bonds. Similarly, if the repeating units of polymer A have ester bonds, then the repeating units of polymer B also have ester bonds.

[0061] In the case of using a hygroscopic polymer in the crimped fiber of this embodiment, if polymer A or polymer B is an aromatic polyester, it is preferable to use a polyether ester as the hygroscopic polymer. Furthermore, if polymer A or polymer B is an aliphatic polyamide, it is preferable to use a polyether amide or a polyether ester amide as the hygroscopic polymer. Through these combinations, the two polymers have high affinity, which can improve the durability at the interface between the two polymers. Moreover, the stress generated by the volume expansion of the fiber during moisture absorption can be dispersed by the elongation imparted to the composite fiber by the crimping, so that deformation strain does not accumulate on the fiber surface or inside the fiber, thereby further improving the durability of the crimped fiber.

[0062] Furthermore, the term "polymer combination with high affinity" here can be selected, for example, based on the solubility parameters (SP values) of the two polymers. The "SP value" is defined as (evaporation energy / mole volume) / 2, reflecting the cohesive force of a substance; the closer the value is to this value, the higher the affinity of the polymer combination. The SP value is known data for various polymers, as recorded, for example, on page 189 of the "Plastics Data Set" (co-edited by Asahi Kasei Amidas Co., Ltd. / Plastics Editorial Department, 1999).

[0063] In this embodiment, if the absolute value of the difference in SP values ​​between the two selected polymers is less than or equal to 4 (MJ / m³)¹ / ², then the two polymers have good adhesion, which is preferable. More preferably, the absolute value of the difference in SP values ​​between the two selected polymers is less than or equal to 3 (MJ / m³)¹ / ², and even more preferably, it is less than or equal to 2 (MJ / m³)¹ / ².

[0064] To achieve the objective of this invention, as a preferred example of the above-described polymer combination, if polymer A or polymer B is an aromatic polyester, examples include: polyethylene terephthalate and polyether ester (a copolymer of polyethylene terephthalate and polyethylene glycol), polyethylene terephthalate and polyether ester (a copolymer of polybutylene terephthalate and polyethylene glycol), polybutylene terephthalate and polyether ester (a copolymer of polybutylene terephthalate and polyethylene glycol), etc. Among these, it is preferred that polymer A is configured with polyether ester (a copolymer of polybutylene terephthalate and polyethylene glycol), and polymer B is configured with polybutylene terephthalate. In this case, because polymer B is a soft and easily deformable polybutylene terephthalate (PET), even if the fiber volume swells upon moisture absorption, the deformation of polymer B, combined with the stress dispersion effect caused by the curling morphology, can further improve the durability of the surface layer of the curled fiber. Furthermore, because both polymer A and polymer B have a PET structure, deformation strain does not accumulate at the interface where polymer A and polymer B meet, further enhancing the durability of the curled fiber.

[0065] Furthermore, an example of a preferred combination when polymer A or polymer B is an aliphatic polyamide is, for example: polydecylamine and polyether ester amide (polydecylamine with adipic acid bonded at the end, copolymerized with polyethylene glycol), polydecylamine and polyether ester amide (polydecylamine with p-phthalic acid bonded at the end, copolymerized with polyethylene glycol), polyhexamethylene hexamethylenediamine and polyether ester amide (polydecylamine with p-phthalic acid bonded at the end, copolymerized with polyethylene glycol), polyhexamethylene decanediamine and polyether ester amide (polydecylamine with p-phthalic acid bonded at the end, copolymerized with polyethylene glycol), polydecylamine and polydecylamine with added polyvinylpyrrolidone, etc. Of these, a preferred combination is polymer A containing polyether ester amide (a copolymer of polydecylamine with p-phthalic acid bonded at the ends and polyethylene glycol) and polymer B containing polydecylamine. In this case, because polymer B is a hygroscopic polydecylamine, a crimped fiber possessing both excellent hygroscopic properties and mechanical properties can be obtained. Furthermore, since polydecylamine is also a soft and easily deformable polymer, even if the fiber swells upon absorbing moisture, the deformation of polymer B combined with the stress dispersion effect caused by the crimped shape further improves the durability of the fiber surface layer. Moreover, since both polymer A and polymer B have a polydecylamine structure, the durability at the interface between polymer A and polymer B is further improved.

[0066] When the crimped fiber of this embodiment is composed of aliphatic polyamine, it is particularly easy to deform and the amount of deformation is also greater due to the low glass transition point of the polymer, which is aliphatic polyamine. When the crimped fiber is repeatedly stretched and deformed due to moisture absorption and / or water absorption, or when the crimped fiber is deformed due to external forces, the durability of the crimped fiber can be further improved, which is preferable. From this point of view, when the crimped fiber of this embodiment is composed of aliphatic polyamine, especially when polymer B is aliphatic polyamine, the α-type crystallization alignment parameter of the polyamine belonging to polymer B is preferably 1.7 or higher and 2.6 or lower.

[0067] The α-type crystal of polyamide is a stable crystalline form, formed under high stress. If the α-type crystal alignment parameter of the polyamide belonging to polymer B is 1.7 or higher, polyamide crystallization occurs, resulting in excellent durability of the coiled fiber. Therefore, even if the coiled fiber elongates due to moisture absorption and / or water absorption, or if the coiled fiber deforms due to external forces, it still exhibits good durability. On the other hand, if the α-type crystal alignment parameter of the polyamide is 2.6 or lower, the polyamide crystallization is not sufficient, resulting in a soft, coiled shape that is easily elongated and deformed. Furthermore, because water molecules can penetrate the fiber, the moisture absorption performance is also excellent. When polymer B is an aliphatic polyamide, the α-type crystal alignment parameter of the polyamide belonging to polymer B is preferably 1.8 or higher and 2.5 or lower.

[0068] In the cross-section of the crimped fiber of this embodiment, the composite configuration of the two polymers is provided that polymer A is completely covered by polymer B, and there are no other particular limitations. However, in order to achieve the purpose of this invention, it is preferable that the center of gravity of polymer A is different from the eccentric core-sheath cross-section at the center of the fiber cross-section.

[0069] The "center of gravity of polymer A" referred to here is point a in Figure 2(a), and the "center of fiber cross-section" is point c in Figure 2(a). In the coiled fiber of this embodiment, by separating the center of gravity a of polymer A from the center c of the fiber cross-section, the fiber becomes a three-dimensional helical structure, and can well exhibit a coiled shape in the direction of the fiber axis. Furthermore, in the coiled fiber of this embodiment, when the composite shape is an eccentric core-sheath cross-section, it is preferable to satisfy the following two requirements: (A) The ratio S / df of the minimum thickness S of polymer B covering polymer A to the single fiber diameter df is 0.01 or more and 0.10 or less. (B) The portion having a thickness of 1.05 times or less than the minimum thickness S has a circumference of 30% or more of the fiber cross-section circumference (hereinafter also referred to as "S ratio").

[0070] The phrase "the minimum thickness S of polymer B covering polymer A" is determined as follows: The coiled fiber of this embodiment is encapsulated with an encapsulating agent such as epoxy resin while maintaining the fiber bundle state. An image of the fiber cross-section is captured using a transmission electron microscope (TEM) at a magnification that allows observation of more than 10 fibers. If metallic staining is performed, the difference in staining intensity between the polymers can clearly distinguish the contrast between the junction of polymer A and polymer B. One single fiber is randomly sampled from the captured image. As shown in Figure 2(b), an arbitrary point E at the interface between polymer A and polymer B is selected, and a tangent line 6 is drawn at point E. Next, a perpendicular line is drawn from point E to the fiber surface, and the intersection point F with the fiber surface is determined. The length of line segment EF is measured to three decimal places, and the minimum length of line segment EF is set as the thickness (μm) (symbol 7 in Figure 2). This operation is repeated for 10 randomly sampled single fibers from the same image. The simple number average of the thicknesses is calculated, and the value rounded to the third decimal place is set as the minimum thickness S (μm). Then, using the image from which the minimum thickness S is determined, the single fiber diameter df (μm) is measured according to the above method. Using the obtained S and df, S / df is calculated and rounded to the third decimal place.

[0071] By using a composite structure with an eccentric core-sheath cross-section that satisfies the above requirements, the distance between the center of gravity a of polymer A and the center c of the fiber cross-section can be freely set, resulting in a good coil-like curled shape in the fiber axis direction. This disperses the stress generated by the volume expansion during moisture absorption, thus producing sufficient curling elongation deformation. Furthermore, the coil-like curled shape allows for the creation of fabrics and other fiber structures that exhibit water absorption and moderate stretchability, making them a material with excellent wearing comfort.

[0072] The cross-sectional shape of the curled fiber in this embodiment is not only circular, but can also be a variety of cross-sectional shapes such as flat, Y-shaped, T-shaped, hollow, field-shaped, well-shaped, etc.

[0073] The crimped fiber system of this embodiment can be any form, such as long fiber (filament) or short fiber (staple). In the case of long fiber, it can be a monofilament yarn composed of a single monofilament or a multifilament composed of multiple monofilaments. In the case of short fiber, there are no limitations on the cut length or the number of crimps.

[0074] The fineness of the crimped fiber in this embodiment can be appropriately set according to the application. If it is a long fiber for clothing, it is more practical to have a fineness of 8 dtex or more and 150 dtex or less.

[0075] Furthermore, for clothing, the strength is better at 1.5 cN / dtex or higher. When making fabrics, by taking measures such as combining other fibers, it is possible to use them without any problems even if the strength is below 1.5 cN / dtex.

[0076] The elongation can be appropriately set according to the application. From the viewpoint of processability when processing the fabric, it is preferable to be 25% or more and 60% or less. In addition, in the case of performing the post-processing described above, it is best to set the fiber elongation before performing the post-processing to 60% or more and 250% or less.

[0077] The single fiber fineness of the crimped fiber in this embodiment is preferably 8.0 dtex or less. By setting the single fiber fineness within this range, the stiffness of the coiled crimped form can be reduced, resulting in a fiber structure with excellent mechanical properties and heat resistance, and excellent wearing comfort due to moderate stretchability. Furthermore, the stress generated by volume expansion during moisture absorption can be dispersed by the elongation of the crimp, preventing the accumulation of deformation strain on the fiber surface or inside the fiber, thus exhibiting excellent quality when made into woven fabrics. The single fiber fineness is preferably 5.0 dtex or less, and ideally 3.0 dtex or less.

[0078] When the crimped fiber of this embodiment is composed of aromatic polyester, the rigidity of the fiber is increased by utilizing the molecular structure, thus maintaining the crimped shape. On the other hand, when the crimped fiber hardens, elongates and deforms due to moisture absorption and / or water absorption, or when external force is applied, the crimped fiber will deform elastically, which can improve its durability against repeated deformation, and is therefore preferable.

[0079] From this perspective, in the crimped fiber of this embodiment, if polymer A or polymer B is an aromatic polyester, the initial tensile resistance is preferably above 10 cN / dtex and below 100 cN / dtex. The so-called "initial tensile resistance" is measured according to the method described in Section 8.10 of the Chemical Fiber Yarn Test Method (JIS L1013(2010)), and is related to the apparent Young's modulus, that is, it represents the ease with which the fiber deforms.

[0080] If the initial tensile resistance is 10 cN / dtex or higher, the coiled shape is rigid, so even if elongation occurs, the coil will not fatigue. After elongation by absorbing moisture and / or water, it can return to its original coiled shape by releasing moisture and / or drying. On the other hand, if the initial tensile resistance is below 100 cN / dtex, the stiffness of the coiled shape can be reduced. The stress generated by the volume expansion during moisture absorption can be dispersed by the elongation of the coil, so that deformation strain does not accumulate on the fiber surface or inside the fiber, resulting in excellent quality when made into woven fabric.

[0081] The crimped fiber of this embodiment can be obtained using known methods such as melt spinning and composite spinning, as exemplified below. However, the spinning method and composite method are not limited to those exemplified here.

[0082] Methods for manufacturing the shredded fiber of this embodiment, composed of two polymers, include, for example, melt spinning for the purpose of manufacturing long fibers, solution spinning methods such as wet and dry-wet spinning, meltblowing suitable for obtaining sheet-like fiber structures, and spunbonding. Among these, melt spinning is preferred from the viewpoint of improving productivity. When using melt spinning, the spinning temperature is set to the temperature at which the main high-melting-point or high-viscosity polymers used exhibit fluidity. This fluidity-indicating temperature varies depending on the molecular weight; it is preferable to set it between the polymer's melting point and melting point + 60°C for stable manufacturing.

[0083] As a manufacturing method using melt spinning, polymer A and polymer B are melted separately, metered and transported using a gear pump, and a composite flow is formed in a manner that creates a specific composite structure using a known method, and then ejected from a spinning spinneret. The ejected filament is cooled to room temperature by blowing cooling air through a filament cooling device such as a chimney pipe, and then oiled and bundled using an oil supply device. The bundled filament is then interlaced using a fluid interlacing nozzle device, and then passed through a traction roller and a stretching roller. At this time, stretching is performed according to the ratio of the circumferential speed of the traction roller and the stretching roller. Another example is a method in which the filament is heat-set using a stretching roller and then wound using a winding machine (winding device). Other examples include a two-stage method in which the circumferential speeds of the traction roller and the stretching roller are set to the same speed, and then the unstretched filament is formed by winding using a winding machine at the same speed, and then stretching is performed using other steps.

[0084] In the crimped fiber of this embodiment, the composite polymer flow can be stably formed by the melt viscosity ratio of the two polymers (high melt viscosity polymer / low melt viscosity polymer) being less than 5.0, and fibers with good composite cross-sections can be obtained, which is better.

[0085] Furthermore, in view of the purpose of the present invention, it is preferable to have a polymer combination that produces a shrinkage difference during heat treatment, and the difference in melt viscosity of the two polymers in the combination is preferably 10 Pa·s or more.

[0086] The composite spinneret used in manufacturing the crimped fiber of this embodiment is preferably the composite spinneret described in Japanese Patent Application Publication No. 2011-208313. As shown in Figure 3, the composite spinneret is assembled within a spinneret assembly, consisting of three components roughly divided from the top accumulation layer: a metering plate 9, a distribution plate 10, and an ejection plate 11, for spinning. Conventional composite spinnerets, as described above, are difficult to control in terms of composite cross-sectional shape; therefore, it is preferable to use a composite spinneret utilizing a micro-flow path, as illustrated in Figure 3.

[0087] The spinneret component illustrated in Figure 3 is formed by metering plate 9 measuring the amount of polymer flowing into each discharge hole and each distribution hole, then using distribution plate 10 to control the composite cross section and its cross section shape of the single fiber, and then using discharge plate 11 to compress and discharge the composite polymer flow formed by distribution plate 10.

[0088] Although not illustrated to avoid complicating the explanation of the composite spinneret, the components stacked above the metering plate 9 can also be used with the spinning machine and the spinneret assembly to form a flow path. By combining the metering plate 9 with existing flow path components, existing spinneret assemblies and their components can be directly utilized, thus eliminating the need to specialize the spinning machine for this spinneret.

[0089] Furthermore, multiple flow path plates can be stacked between the flow path and the metering plate 9, or between the metering plate 9 and the distribution plate 10. This allows for the efficient transfer of polymer in both the spinneret cross-section direction and the single fiber cross-section direction, and the distribution plate 10 can be configured. After the composite polymer stream ejected from the ejection plate 11 is cooled and solidified according to the above manufacturing method, an oil is applied, and then it is drawn using a roller at a predetermined circumferential speed to obtain a fiber with the desired composite cross-section. When the composite form in the crimped fiber of this embodiment is an eccentric core-sheath cross-section, from the viewpoint of stably forming the cross-section, it is preferable to use the above-described composite spinneret.

[0090] In the crimped fiber of this embodiment, the composite ratio of polymer A to polymer B, based on the mass ratio of polymer A to polymer B, is preferably 70 / 30 to 20 / 80. By setting it within this range, the two polymers are oriented differently using the spinning and stretching steps, resulting in a difference in shrinkage during heat treatment, thus obtaining a fiber with excellent crimping properties. Furthermore, when a hygroscopic polymer is used as polymer A, ΔMR and destatic properties can be controlled within the specific range of the crimped fiber of this embodiment. The mass ratio of polymer A to polymer B is more preferably 60 / 40 to 30 / 70.

[0091] In the fabrication of the coiled fibers of this embodiment, the spun traction represented by the ratio of the spitting line speed of the nozzle to the speed of the traction roller (traction roller speed / jet nozzle spitting out line speed) is preferably above 10 and less than 300. The term “spit line velocity of the nozzle” here is the numerical value of the spitting volume per unit time of the polymer spewed from the hole of the spitting plate 11 of the composite nozzle, divided by the cross-sectional area of ​​the spitting hole of the nozzle.

[0092] The spun traction is associated with the fiber alignment produced during the period after spitting from the hole of the spitting plate 11 of the composite jet nozzle through cooling until traction is carried out by the traction roller, the greater the spun traction, the greater the fiber alignment until it is traction by the traction roller. Furthermore, when the curled fiber as in the present embodiment is constituted of two polymers with poor melt viscosity, fibers with excellent curling characteristics can be obtained because poor alignment is produced by the two polymers, thereby producing poor shrinkage during heat treatment.

[0093] If the spun yarn traction is less than 300, the tension applied to the polymer just spit out from the composite yarn nozzle can be reduced, which can suppress the strand breakage due to excessive tension applied until it is traction by the traction roller. Also, if the spun yarn traction reaches more than Spinning traction is preferably 30 or more, and less than 150.

[0094] In the fabrication of the coiled fibers of this embodiment, when thermal shaping is applied on the roller after extension, the heat treatment is preferably applied according to the tensioned state, and then, cooled below the glass transition point while maintaining tension. If the configuration of the polymer molecular chains of the fibers is fixed by the application of tensioning heat treatment and tensioning cooling treatment, the shrinkage stress can be improved, so the ratio Dc / df of the coil diameter Dc to the single fiber diameter df, and the number of coil pitches can be effectively controlled within the specificity of the coiled fibers of the present embodiment.

[0095] The curled fibers of this embodiment not only show curling by utilizing the poor heat shrinkage of polymers such as described above, but also perform post-processing such as false pin machining and screw thread machining to show curling. Preferably a curling construction having those two. The rationale is that in addition to using the thermal shrinkage difference of the polymer to cause curling, the two curling morphologies are mixed by performing yarn processing, thus the ratio Dc / df of the coil diameter Dc to the single fiber diameter df, and the coil pitch number can be controlled within the specificity of the coiled fibers of the present embodiment.

[0096] For example, as a method of performing dummy processing, under the premise of general methods such as polyamide and polyester, the rest are not particularly limited. In order to stably manufacture the curled fibers of this embodiment using dummy processing, it is preferable to control the curled morphology using the actual screw degree of the addition region. That is, it is best to set the revolutions, processing speed and other false conditions of the adding mechanism in a way that satisfies the following conditions. 5000 / Fi 0.5≦T≦40000 / Fi 0.5

[0097] Where, T is the number of dummy pins indicating the number of pins in the plus pin region (times / m), and Fi is the total fiber (dtex) of the machined yarn after machining processing by dummy pin twisting. In addition, the sham number T was determined according to the following method. The processing thread that swims away in the adding area during the fake cock step is taken more than 50cm in a way that does not cause unstitching before using the screwing machine. Then, the taken silk samples were mounted on the pin number testing machine, and the pin number was determined according to the method recorded in JIS L1013 (2010) 8.13, and set as the false number T. By satisfying the above conditions by the fake number T, the curling morphology can be controlled, which can not only suppress the reduction of fabric quality of roughness, streaks, etc., but also play the effect of the purpose of the present invention.

[0098] A fiber construct composed of a curled fiber and / or post-processed yarn of the present embodiment is well suited to adopting an arbitrary knitted fabric or braided fabric, and may also be adapted for plain weave, shuttle weave, juzi weave or variations thereof, or warp knitting, weft knitting, circular knitting, lace knitting, or variations such as warp knitting.

[0099] The coiled fibers of the present embodiment may be combined with other fibers using cross-braid, cross-knitting, etc. when forming a fiber structure, and may also form a hybrid fiber with other fibers after forming a fiber structure.

[0100] Fiber constructs composed of coiled fibers and / or post-processed yarns of this embodiment are well suited for applications requiring comfort, quality because of their excellent hygroscopicity. For example: general clothing use, sportswear use, bedding use, decoration use, material use, etc., but are not limited to those.

[0101] As explained above, this specification discloses the following structure. <1> A coiled fiber, a composite fiber composed of two polymers, polymer A and polymer B, having a coiled shape in the fiber axis direction, wherein the ratio of the coil diameter Dc to the single fiber diameter df, Dc / df, is 2.0 or more and 20.0 or less, the number of coil pitches is 1.0 or more / mm and 10.0 or less, polymer A is completely covered by polymer B in the fiber cross-section, and the moisture absorption / desorption parameter ΔMR reaches 2.0% or more. <2> The coiled fiber as described in <1>, wherein, of the two polymers, polymer A has higher hygroscopicity. <3> The coiled fiber as described in <1> or <2>, wherein, in the main skeleton of the repeating unit constituting each of the two polymers, the same type of bond is present. <4> A fiber product using the coiled fiber described in any one of <1> to <3>. [Example]

[0102] The present invention will be described in detail with reference to embodiments, but the present invention is not limited to these embodiments. In addition, the characteristic values ​​in the embodiments were measured using the following methods.

[0103] A. Melt Viscosity of Polymers: For polymer samples with a moisture content of less than 300 ppm obtained by vacuum drying, a capillary rheometer from Toyo Seiki was used. The sample was placed in a heating furnace set at the same temperature as the spinning temperature and melted under nitrogen conditions. The strain rate was changed in stages, and the sample was extruded from the capillary at the front end of the heating furnace, and the viscosity was measured. In addition, the measurement was started 5 minutes after the sample was placed in the heating furnace, and the value at a shear rate of 1216 sec⁻¹ was set as the melt viscosity of the polymer.

[0104] B. Melting point (Tm) of the polymer: Using a TA Instruments differential scanning calorimeter (DSC) Q2000, 20 mg of polymer sample was heated from 20°C to 280°C at a heating rate of 20°C / min, held at 280°C for 5 minutes, then cooled back to 20°C at a cooling rate of 20°C / min, held at 20°C for 1 minute, and then heated back to 280°C at a heating rate of 20°C / min. The peak temperature of the endothermic peak observed during this heating process was taken as the melting point. Furthermore, in the case of multiple endothermic peaks observed, the peak of the highest temperature endothermic peak was taken as the melting point.

[0105] C. Fineness: The fiber sample was wound 200 times using a spinning machine with a frame circumference of 1.125m to make a skein. After drying using a hot air dryer (105±2℃×60 minutes), the mass of the skein was weighed using a balance. The fineness was calculated by multiplying the warp by the standard moisture regain. The test was performed 4 times, and the average value was taken as the fineness.

[0106] D. Strength and elongation were measured using an ORIENTEC (stock) "TENSILON" (registered trademark) UCT-100 testing machine. The fiber samples were tested under constant elongation conditions as shown in the Chemical Fiber Yarn Test Method (JIS L1013 (2010)). Elongation was obtained from the elongation at maximum strength as represented by the tensile strength-elongation curve. Strength was set as the maximum strength divided by the fineness. The test was performed 10 times, and the average value was set as the strength and elongation.

[0107] E.ΔMR (ΔMR before hot water treatment) Measure about 1~2g of fiber or fabric sample into a weighing bottle, dry it at 110℃ for 2 hours and measure the mass. Set this mass as w0. Then, keep the dried fiber sample at 20℃ and 65% relative humidity for 24 hours and measure the mass. Set this mass as w65%. Then, adjust the temperature to 30℃ and 90% relative humidity, keep the fiber sample at 24 hours and measure the mass. Set this mass as w90%. MR1=[(w65%-w0) / w0]×100・・・(1) MR2=[(w90%-w0) / w0]×100・・・(2) ΔMR=MR2-MR1・・・(3) At this time, the result calculated by formulas (1)~(3) is set as ΔMR.

[0108] F. ΔMR after hot water treatment: Using a circular knitting machine (NCR-BL, 3.5-inch cylinder diameter, 27 gauge pressure) manufactured by Yingguang Industry (3.5 inches (8.9 cm), 27 gauge pressure), the needle count was adjusted to 50 to produce tubular knitted fabric. When the fiber's total fineness was less than 80 dtex, appropriate plying was performed according to the method of supplying the yarn to the tubular knitting machine with a total fineness of 80~160 dtex. When the total fineness exceeded 80 dtex, it was supplied to the tubular knitting machine as a single yarn. Next, the obtained tubular knitted fabric was immersed in an aqueous solution containing 1 g / L sodium carbonate and SANMOL BK-80 surfactant manufactured by Nichika Chemicals. The aqueous solution was heated to 80°C and treated for 20 minutes, and then dried in a 60°C hot air dryer for 60 minutes. Furthermore, the dried tubular knitted fabric was subjected to hot water treatment in water at 130°C for 60 minutes, with the solution being 100 times its own weight. Following this, it was dried in a 60°C hot air dryer for 60 minutes to obtain the hot-treated tubular knitted fabric. ΔMR was calculated from the obtained hot-treated tubular knitted fabric according to item E.

[0109] G. Coil Diameter Dc The fiber sample was formed into a 10m skein using a spinning machine, etc., and a load of 0.2mg / d was applied. It was then immersed in boiling water above 98°C for 15 minutes. After the boiled water-treated yarn was thoroughly dried by air drying, a load of 2mg / d was applied for at least 30 seconds. Two points were then marked at random points on the yarn bundle, with a distance of 3cm between them. Then, individual fibers were separated from the yarn bundle in a manner that prevents plastic deformation. These fibers were adjusted to the pre-marked distance of 3cm and fixed on a glass plate. Images of this sample were taken using a digital microscope manufactured by KEYENCE, at a magnification that allowed observation of 5-10 curled ridges. In each image, the vertices of any adjacent ridges were designated as M1 and M2, and the valley between M1 and M2 was designated as V. The shortest distance D (μm) between the connecting line of M1 and M2 and V was measured to two decimal places. Different single fibers were randomly selected and the same operation was performed. By repeating this operation, the shortest distance D was measured in groups of 50. The simple numerical average of the 50 measured shortest distances D was calculated, and the value rounded to the second decimal place was set as the coil diameter Dc (μm).

[0110] H. Single Fiber Diameter df The fiber sample treated in section G is encapsulated with an encapsulating agent such as epoxy resin. Images of the fiber cross-section perpendicular to the fiber axis are captured using a HITACHI scanning electron microscope (SEM) at a magnification that allows observation of 10 or more single fibers. From each captured image, the diameter of a randomly sampled single fiber within the same image is measured to three decimal places in μm. This process is performed on 10 randomly sampled single fibers. The simple quantitative average of the measurement results is calculated, and the value rounded to three decimal places is taken as the single fiber diameter df (μm). Here, when the fiber cross-section perpendicular to the fiber axis is not a perfect circle, the obtained image is analyzed using the computer software Mitani Shoji WinROOF, and the area is measured. This area is then converted to a circle with the same area, and the diameter of that circle is used. Alternatively, images for measurement can also be captured using a transmission electron microscope (TEM).

[0111] I. The number of coil pitches is determined by taking the image taken when measuring the coil diameter Dc in item G. For the coil-shaped coiled shape, the distance (mm) between any two adjacent ridge vertices M1 and M2 is calculated to two decimal places. The measurement is performed at any three points for each single fiber. This operation is performed for 10 different single fibers. The reciprocal of the simple numerical average of the measured results is calculated, and the value rounded to two decimal places is set as the number of coil pitches (number / mm).

[0112] J. Stretch elongation rate Using a hank winder with an appropriate tension adjustment device, make a hank of yarn with 10 turns for the fiber sample. Select the treatment temperature according to item 6 of JIS L1013 (2010), and perform hydrothermal treatment under a load of 0.2 mg / d. Then, perform the treatment according to method C (simple method) of item 8.11 of JIS L1013 (2010) to obtain the stretch elongation rate.

[0113] K. Water absorption elongation rate Using a hank winder with an appropriate tension adjustment device, make a hank of yarn with 10 turns for the fiber sample. Select the treatment temperature according to item 6 of JIS L1013 (2010), and perform hydrothermal treatment under a load of 0.2 mg / d. Then, apply a load of 0.1 g / d to the hank of yarn, keep it at a temperature of 20°C and a relative humidity of 65% for 24 hours, and then obtain the length L0 of the fiber sample under a load of 0.1 g / d. Next, immerse it in water at 20°C for 1 minute without load and then take it out, and apply a load of 0.1 g / d to obtain the length L1 after 10 seconds. Calculate the water absorption elongation rate using the obtained lengths by formula (4). Water absorption elongation rate (%) = [(L1 - L0) / L0] × 100... (4)

[0114] L. Number of defects on the fiber surface and inside the fiber For the tubular knitted fabric produced by the method described in item F and subjected to hot water treatment, perform evaporation coating using a platinum-palladium alloy, and observe it at a magnification of 1000 times using a Hitachi scanning electron microscope (SEM) model S-4000, and randomly take 10 field microscope photos. In the 10 field photos obtained, observe the fiber surface of the tubular knitted fabric and count the places where fractures occur. Furthermore, randomly extract 5 fibers from the tubular knitted fabric after hot water treatment, and take images of each fiber sample at a magnification that can observe all single fibers. From each of the taken images, randomly sample single fibers within the same image and count the number of voids inside the fibers. The sum of the number of fractures on the fiber surface and the number of voids inside the fibers is set as the number of defects, and if the number of defects is 10 or less, it is evaluated as qualified.

[0115] The M.α-type crystal alignment parameter was determined by laser Raman spectroscopy analysis of the fiber sample. The ratio of the intensity ratio under parallel polarized light ((I1120) parallel) and the intensity ratio under perpendicular polarized light ((I1120) perpendicular) of the Raman band of the α-type crystals derived from polyamide identified near 1120 cm⁻¹ was calculated and set as the parameter for evaluating the alignment degree. Furthermore, the Raman band intensity of the CH deformation band (near 1440 cm⁻¹) with relatively small anisotropy for alignment was used as a reference, and the scattering intensity under each polarization condition (parallel / perpendicular) was formatted. α-type crystal alignment parameter = (I1120 / I1440) parallel / (I1120 / I1440) perpendicular. In addition, the sample used for alignment determination was coated with resin (bisphenol epoxy resin, cured for 24 hours) and sliced ​​using a slicer. The slice thickness was set to 2.0 μm. The sample was cut into an elliptical shape with a slight inclination along the fiber axis, and measurements were taken at locations where the thickness of the minor axis of the ellipse was constant. Measurements were performed using a microscope with a laser spot diameter of 1 μm at the sample location. Orientation analysis was conducted on the core and sheath centers under polarized light. A parallel condition was defined as the polarization direction aligned with the fiber axis, and a perpendicular condition was defined as the polarization direction orthogonal. The degree of orientation was evaluated by the ratio of the intensities of each Raman band. Furthermore, n=3 measurements were performed at each measurement point. Detailed conditions are shown below.

[0116] Laser Raman Spectroscopy Analysis Apparatus: T-64000 (Joobin Yvon / Atago Bussan) Conditions: Measurement mode; Micro Raman objective: ×100 Beam diameter: 1μm Light source: Ar+ laser / 514.5nm Laser power: 50mW Diffraction grating: Single 600gr / mm Slit: 100μm Detector: CCD / Jobin Yvon 1024×256.

[0117] N. Uneven dyeing: The tubular knitted fabric was prepared according to the method described in section F. Next, the obtained tubular knitted fabric was placed in an aqueous solution containing 1 g / L sodium carbonate and SANMOL BK-80 surfactant manufactured by Nichika Chemicals. The aqueous solution was heated to 80°C and treated for 20 minutes, followed by drying in a 60°C hot air dryer for 60 minutes. Then, it was heat-set at 160°C for 2 minutes. The heat-set tubular knitted fabric was then placed in a dyeing solution containing dyes and auxiliaries corresponding to the fiber type constituting the tubular knitted fabric, at a weight of 100 times the weight of the tubular knitted fabric. Dyeing was performed at a temperature and time corresponding to the fiber type. The dyed tubular knitted fabric was used as a sample. A MINOLTA CM-3700d spectrophotometer was used with a D65 light source, a 10° field of view, and SCE (excluding specular reflection) optical conditions. Three L-value measurements were performed on each sample, and the average value was rounded to the second decimal place and set as the L-value. This process was repeated for 10 randomly sampled samples. The rate of change was calculated from the average L-value of the 10 samples to the standard deviation. If the rate of change of the L-value of the 10 samples was below 5.0%, it was considered that there was no uneven dyeing.

[0118] O. Abrasion resistance: The tubular knitted fabric, made according to the method described in section F and subjected to hot water treatment, shall be tested according to JIS L1096(2010) 8.19 E method (MARTINDALE method). The abrasion resistance shall be evaluated at the endpoint when filament breakage or appearance change occurs. A minimum of 2500 cycles at the endpoint shall be considered acceptable.

[0119] P. Water Absorption and Quick-Drying Properties (Drying Speed) The tubular knitted fabric prepared according to the method described in section F and subjected to hot water treatment is kept at 20°C and 65% relative humidity for 24 hours. The mass is then measured and designated as wa. Next, 0.3 ml of water is dripped into the center of the sample and the mass is measured. This mass is designated as w0 minutes. The instant the water is dripped into the sample is designated as 0 minutes, and the mass of the sample is measured at 5-minute intervals. This mass is designated as wn minutes. Here, "n minutes" represents any time interval for measuring the mass of the sample, such as 5 minutes, 10 minutes, 15 minutes, etc. The moisture residue rate WR at any time is calculated according to formula (5). WR=[(w 0 min - wn min) / (w 0 min - wa)]×100・・・(5) If the moisture residue rate WR calculated by formula (5) is less than 30% for less than 75 minutes, it is rated as good drying performance. If it is less than 60 minutes, it indicates that it has water absorption and quick drying performance.

[0120] Q. Maintenance of hygroscopicity before and after hot water treatment (ΔMR change due to hot water treatment) The difference between the ΔMR calculated in item F after hot water treatment and the ΔMR calculated in item E before hot water treatment is used to evaluate the change in fiber hygroscopicity before and after hot water treatment. If the ΔMR change is less than 2.0%, the fiber hygroscopicity is considered to be maintained before and after hot water treatment.

[0121] R. Destatic properties: The tubular knitted fabric, which is made according to the method described in section F and subjected to hot water treatment, is subjected to a voltage applied at a temperature of 20°C and a relative humidity of 40%, according to JIS L1094 (Method for testing the charge of fabrics and knitted fabrics, 2014) Method A (half-life determination method), and the time taken for the original fabric to reduce its charge voltage to 50% of the initial charge voltage is measured.

[0122] S. Wearing Evaluation (Heat Sensation) The fiber sample obtained according to the example was adjusted to a basis weight of 100~150g / m2 to make circular knitted fabric according to known methods. Next, the obtained knitted fabric was sewn to make a shirt-like garment. Ten test subjects wore the garment. Then, they were moved to a summer indoor environment with a temperature of 30°C and a relative humidity of 60% without air conditioning and sat quietly in chairs. From the time they sat down until one hour later, the condition of the garment inside was evaluated six times every 10 minutes. The scores were calculated as follows: "No heat sensation at all": 5 points, "Almost no heat sensation": 4 points, "Slight heat sensation": 3 points, "Heat sensation": 2 points, "Strong heat sensation": 1 point. The ten test subjects gave scores at each time point, and the average score was calculated. Those who achieve an average score of 3.0 or above from all 6 scores are rated as qualified, and those who achieve a score of 4.0 or above are rated as excellent.

[0123] T. Single Fiber Fineness: Using a KEYENCE VHX2000 digital microscope at 300x magnification, images were taken of the cross-section of the fiber sample, and the number of single fibers contained in the fiber sample was counted. Then, the fineness determined according to the method described in section C was divided by the number of single fibers, and the value was rounded to the first decimal place and set as the single fiber fineness.

[0124] U. Initial tensile strength is obtained from the tensile strength-elongation curve obtained when the fiber sample is tested according to the method described in section D, and the initial tensile strength is determined according to the method shown in section 8.10 of the Chemical Fiber Yarn Test Method (JIS L1013(2010)).

[0125] (Example 1) At a spinning temperature of 270°C, polybutylene terephthalate (melt viscosity 60 Pa·s, melting point 217°C), copolymerized from 50% by mass of polyethylene glycol (PEG6000S manufactured by Sanyo Chemical Industry) with a quantity average molecular weight of 8300 g / mol, was used as polymer A, and polybutylene terephthalate (melt viscosity 110 Pa·s, melting point 222°C) was used as polymer B. After melting each polymer separately, it was measured according to the composite ratio of polymer A and polymer B as 30 / 70 by mass, and then flowed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. Then, with an eccentric core sheath cross-section of S / df of 0.06 and S ratio of 35%, the polymer was discharged from the discharge orifice (orifice diameter 0.23 mm, number of orifices 24). The extruded composite polymer stream is cooled and solidified using a cooling device, and then supplied with an oil-containing oiling agent using an oil supply device. Next, the circumferential speed of the traction roller (first roller) is set to 1000 m / min, and the temperature is set to 90°C for traction. The spinning draw (traction roller speed / spinneret exit linear speed) at this time is shown in Table 1. Then, the filament drawn by the traction roller is drawn using the extension roller (second roller) at a surface temperature of 130°C, thereby achieving an extension ratio of 2.02 times, expressed as the ratio of the circumferential speeds of the traction roller and the extension roller. Simultaneously, heat treatment is performed using the extension roller. The heat-treated filament is then wound using a winding machine at a winding speed of 2000 m / min to obtain an 84 dtex-24 count extended filament. The obtained extended filament is then subjected to boiling water treatment to induce shrinkage. The obtained crimped fibers were confirmed to have a coil-like crimped morphology in the fiber axis direction, with a Dc / df ratio of 14.1 and a coil pitch of 2.8 per mm. The evaluation results of the obtained crimped fibers are shown in Table 1.

[0126] (Example 2) Except that the polymer A and polymer B were weighed in a 50 / 50 mass ratio and then fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3, and the polymer was ejected from the discharge orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of S / df of 0.06 and S ratio of 45%, all other conditions were the same as in Example 1 to obtain 84 dtex-24 count crimped fibers. The obtained crimped fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 9.5, and a coil pitch of 1.7 coils / mm. The evaluation results of the obtained crimped fibers are shown in Table 1.

[0127] (Example 3) At a spinning temperature of 285°C, polybutylene terephthalate (melt viscosity 240 Pa·s, melting point 222°C), with a molecular weight different from that of Example 1, was used as polymer B. The polymer A and polymer B were weighed in a 50 / 50 mass ratio and then fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. Next, the polymer was ejected from the ejection orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of 0.06 and an S ratio of 42%. The ejected composite polymer stream was cooled and solidified using a cooling device, and then an aqueous oil was supplied using an oil supply device. Then, the circumferential speed of the traction roller belonging to the first roller was set to 1500 m / min, and the temperature was set to 90°C for traction. Next, the filament drawn by the traction roller was drawn again using the extension roller (second roller) at a surface temperature of 150°C. This resulted in an extension ratio of 2.63, expressed as the ratio of the circumferential speed of the traction roller to that of the extension roller. Simultaneously, heat treatment was performed using the extension roller. The heat-treated filament was then wound using a winding machine at a winding speed of 3890 m / min to obtain 56 dtex-24 count extended filament. The obtained extended filament was then subjected to boiling water treatment to induce shrinkage. The obtained shrinkage fiber was confirmed to have a coil-like shrinkage morphology in the fiber axis direction, a Dc / df ratio of 8.0, and a coil pitch of 2.5 coils / mm. The evaluation results of the obtained shrinkage fiber are shown in Table 1.

[0128] (Example 4) The spinning temperature was set to 290°C, and polyethylene terephthalate (melt viscosity 150 Pa·s, melting point 254°C) containing 2.2% by mass of titanium oxide was used as polymer B. Except for setting the circumferential speed of the traction roller belonging to the first roller to 2000 m / min and the elongation ratio to 1.96, all other conditions were the same as in Example 3 to obtain 56 dtex-24 count extended yarns. The obtained extended yarns were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 18.7, and a coil pitch of 2.2 / mm. The evaluation results of the obtained curled fibers are shown in Table 1.

[0129] (Example 5) Polymer A and polymer B were weighed in a 60 / 40 mass ratio and fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. Then, the polymer was ejected from the ejection orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of S / df of 0.06 and an S ratio of 46%. In the post-ejection steps, except that the elongation ratio was set to 2.50 and the winding speed of the winding machine was set to 3700 m / min, all other conditions were the same as in Example 3 to obtain 56 dtex-24 count elongated filaments. The obtained elongated filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 7.3, and a coil pitch of 2.8 coils / mm. The evaluation results of the obtained curled fibers are shown in Table 1.

[0130] (Example 6) Polymer A and polymer B were weighed in a 30 / 70 mass ratio and then fed into a spinneret assembly with an assembled composite spinneret as shown in Figure 3. Next, the polymer was ejected from the ejection orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of S / df of 0.06 and an S ratio of 33%. In the post-ejection steps, except that the elongation ratio was set to 2.80 and the winding speed of the winding machine was set to 4100 m / min, all other conditions were the same as in Example 3 to obtain 56 dtex-24 count elongated filaments. The obtained elongated filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 9.6, and a coil pitch of 2.6 coils / mm. The evaluation results of the obtained curled fibers are shown in Table 1.

[0131] (Example 7) Except for changing the distribution plate 10 of the composite spinneret shown in Figure 3 to an eccentric core-sheath cross-section with an S / df of 0.09 and an S ratio of 40%, 56 dtex-24 count extended filaments were obtained under the same conditions as in Example 3. The obtained extended filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coil-like curling morphology in the fiber axis direction, a Dc / df of 12.8, and a coil pitch of 1.9 / mm. The evaluation results of the obtained curled fibers are shown in Table 2.

[0132] (Example 8) Except for using polyethylene terephthalate (melt viscosity 68 Pa·s, melting point 251°C), which was copolymerized from 16% by mass of polyethylene glycol (Sanyo Chemical Industry Co., Ltd. PEG6000S) with a number average molecular weight of 8300 g / mol, as polymer A, 56 dtex-24 count extended filaments were obtained under the same conditions as in Example 5. The obtained extended filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 7.5, and a coil pitch of 3.3 / mm. The evaluation results of the obtained curled fibers are shown in Table 2.

[0133] (Example 9) Polybutylene terephthalate (melt viscosity 240 Pa·s, melting point 222°C) was used as polymer A, and polyethylene terephthalate (melt viscosity 68 Pa·s, melting point 251°C), copolymerized from 16% by mass of polyethylene glycol (Sanyo Chemical Industries PEG6000S) with a number average molecular weight of 8300 g / mol, was used as polymer B. The polymers were weighed in a 30 / 70 mass ratio and fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. Then, with an eccentric core-sheath cross-section of 0.06 and an S ratio of 35%, 24 holes (0.23 mm in diameter) were ejected from the discharge holes to obtain 56 dtex-24 strands of filament, except for the polymers flowing in. All other strands were produced under the same conditions as in Example 5. The obtained extended fibers were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coil-like curling morphology in the fiber axis direction, a Dc / df ratio of 2.8, and a coil pitch of 8.2 coils / mm. The evaluation results of the obtained curled fibers are shown in Table 2.

[0134] (Example 10) Except that the number of orifices of the composite spinneret assembled in the spinneret assembly was set to 36, the elongation ratio was set to 2.38, and the winding speed of the winding machine was set to 3480 m / min, all other conditions were the same as in Example 3 to obtain 56 dtex-24 count extended yarn. The obtained extended yarn was subjected to boiling water treatment to make it exhibit shrinkage. The obtained shrinkage fiber was confirmed to have a coil-like shrinkage morphology in the fiber axis direction, a Dc / df of 6.6, and a coil pitch of 2.7 / mm. The evaluation results of the obtained shrinkage fiber are shown in Table 2.

[0135] (Example 11) Except for using polymer A, which contains 44% by mass of polydecylamine, 6% by mass of p-phthalic acid, and 50% by mass of polyethylene glycol with a number average molecular weight of 1450 g / mol, polyether ester amide (melt viscosity 70 Pa·s, melting point 200°C), 56 dtex-24 count filaments were obtained under the same conditions as in Example 3. The obtained filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 6.8, and a coil pitch of 2.9 coils / mm. The evaluation results of the obtained curled fibers are shown in Table 2.

[0136] (Example 12) At a spinning temperature of 270°C, a polyether ester amide (melt viscosity 85 Pa·s, melting point 200°C) containing 44% by mass of polydecylamine, 6% by mass of p-phthalic acid, and 50% by mass of polyethylene glycol with a number average molecular weight of 1450 g / mol was used as polymer A, and polydecylamine (melt viscosity 40 Pa·s, melting point 220°C) was used as polymer B. After melting each polymer separately, it was measured according to the composite ratio of polymer A and polymer B as a mass ratio of 30 / 70, and then flowed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. Then, the polymer was discharged from the discharge orifice (orifice diameter 0.23 mm, number of orifices 24) with an eccentric core-sheath cross-section of S / df of 0.06 and S ratio of 33%. The extruded composite polymer stream was cooled and solidified using a cooling device. After being supplied with a non-aqueous oil using an oil supply device, the traction roller of the first roller was tractioned at a circumferential speed of 1300 m / min. Next, the filament traction-rolled was drawn using the extension roller of the second roller at a surface temperature of 110°C, achieving an extension ratio of 2.54 (expressed as the ratio of the circumferential speeds of the traction and extension rollers). Simultaneously, heat treatment was performed using the extension roller. The heat-treated filament was then wound using a winding machine at a winding speed of 3300 m / min to obtain 56 dtex-24 count extended filament. The obtained extended filament was subjected to boiling water treatment to induce shrinkage. The obtained shrinkage fiber was confirmed to have a coil-like shrinkage morphology in the fiber axis direction, a Dc / df ratio of 5.9, and a coil pitch of 6.6 coils / mm. The evaluation results of the obtained shrinkage fiber are shown in Table 3.

[0137] (Example 13) Polymer A and polymer B were weighed in a 50 / 50 mass ratio and fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. The polymer was ejected from the ejection orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of S / df = 0.06 and S ratio = 43%. In the post-ejection steps, except that the circumferential speed of the traction roller was set to 1500 m / min and the elongation ratio was set to 2.20, all other conditions were the same as in Example 12 to obtain 56 dtex-24 count crimped fibers. The obtained crimped fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 6.0, and a coil pitch of 4.6 coils / mm. The evaluation results of the obtained crimped fibers are shown in Table 3.

[0138] (Example 14) Polydecylamine (melt viscosity 160 Pa·s, melting point 220°C) was used as polymer B. It was measured at a mass ratio of 50:50 for polymer A and polymer B, and then fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. Next, with an eccentric core-sheath cross-section of S / df 0.06 and S ratio 45%, 56 dtex-24 count filaments were obtained from the discharge orifice (0.23 mm diameter, 24 orifices) except for the polymer that flowed in, all other conditions were the same as in Example 13. The obtained filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 6.8, and a coil pitch of 4.9 / mm. The evaluation results of the obtained curled fibers are shown in Table 3.

[0139] (Example 15) Except that polyhexamethylene sebacate (melt viscosity 100 Pa·s, melting point 220°C) was used as polymer B, 56 dtex-24 count crimped fibers were obtained under the same conditions as in Example 13. The obtained crimped fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 6.5, and a coil pitch of 6.7 / mm. The evaluation results of the obtained crimped fibers are shown in Table 3.

[0140] (Example 16) The polymer A and polymer B were weighed in a 60 / 40 mass ratio and then fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. Next, the polymer was ejected from the ejection orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of S / df of 0.06 and an S ratio of 46%. In the post-ejection steps, except that the circumferential speed of the traction roller was set to 1600 m / min and the elongation ratio was set to 2.06, all other conditions were the same as in Example 12 to obtain 56 dtex-24 count extended filaments. The obtained extended filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 5.3, and a coil pitch of 5.0 / mm. The evaluation results of the obtained curled fibers are shown in Table 3.

[0141] (Example 17) Except for changing the distribution plate of the composite spinneret shown in Figure 3 to an eccentric core-sheath cross-section with an S / df of 0.09 and an S ratio of 40%, 56 dtex-24 count extended filaments were obtained under the same conditions as in Example 13. The obtained extended filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coil-like curling morphology in the fiber axis direction, a Dc / df of 5.1, and a coil pitch of 4.8 coils / mm. The evaluation results of the obtained curled fibers are shown in Table 3.

[0142] (Example 18) Except that the spinning temperature was set to 260°C and a polyether ester amide containing 35% by mass of polydecylamine, 6% by mass of adipic acid, and 59% by mass of polyethylene glycol with a number average molecular weight of 1450 g / mol (melt viscosity 55 Pa·s, melting point 200°C) was used as polymer A, 56 dtex-24 count filaments were obtained under the same conditions as in Example 13. The obtained filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 6.4, and a coil pitch of 5.0 loops / mm. The evaluation results of the obtained curled fibers are shown in Table 4.

[0143] (Example 19) Polydecylamine (melt viscosity 160 Pa·s, melting point 220°C) was used as polymer A. Next, polydecylamine masterbatch fragments were prepared by adding 20% ​​by mass of polyvinylpyrrolidone (BASF "Luviskol" K30SP, K value = 30) to polydecylamine without additives. Next, the fragments were blended with the above masterbatch fragments to polydecylamine without additives to adjust to a polydecylamine blended polymer with a polyvinylpyrrolidone addition rate of 5.0% by mass. This blended polymer (melt viscosity 130 Pa·s, melting point 220°C) was used as polymer B. Next, polymer A and polymer B were weighed in a 50 / 50 mass ratio and fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. The polymers were ejected from the discharge orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of S / df = 0.06 and S ratio = 46%. Except for the polymers flowing in, the remaining fibers were produced under the same conditions as in Example 12, yielding 56 dtex-24 count extended filaments. The obtained extended filaments were subjected to boiling water treatment to induce curling. The obtained curled fibers were confirmed to have a coiled shape in the fiber axis direction, a Dc / df of 6.2, and a coil pitch of 9.1 coils / mm. The evaluation results of the obtained curled fibers are shown in Table 4.

[0144] (Example 20) Except that the number of orifices in the composite spinneret assembled with the spinneret assembly was set to 36, and the circumferential speed of the traction roller was set to 1600 m / min and the elongation ratio was set to 2.06, all other conditions were the same as in Example 13 to obtain 56 dtex-24 count extended yarn. The obtained extended yarn was subjected to boiling water treatment to make it exhibit curling. The obtained curled fiber was confirmed to have a coil-like curling morphology in the fiber axis direction, a Dc / df of 5.1, and a coil pitch of 6.0 / mm. The evaluation results of the obtained curled fiber are shown in Table 4.

[0145] (Comparative Example 1) Except for changing the distribution plate of the composite spinneret shown in Figure 3 and making it a concentric core sheath cross-section, 56 dtex-24 count extended yarns were obtained under the same conditions as in Example 3. Although the obtained extended yarns were subjected to boiling water treatment, no shrinkage was observed. The evaluation results of the obtained fibers are shown in Table 5.

[0146] (Comparative Example 2) Except that polybutylene terephthalate (melt viscosity 50 Pa·s, melting point 222°C) was used as polymer B, 56 dtex-24 count filaments were obtained under the same conditions as in Example 3. Although the obtained filaments were subjected to boiling water treatment, no shrinkage was observed. The evaluation results of the obtained fibers are shown in Table 5.

[0147] (Comparative Example 3) Except for changing the distribution plate of the composite spinneret shown in Figure 3 and making it a simple bonding structure with a side-to-side cross-sectional shape, 56 dtex-24 count filaments were obtained under the same conditions as in Example 3. Although the obtained filaments were subjected to boiling water treatment, the shrinkage was weak. Furthermore, because the hygroscopic polymer was exposed on the surface, it dissolved during hot water treatment, resulting in a decrease in the hygroscopicity of the fiber. The evaluation results of the obtained fibers are shown in Table 5.

[0148] (Comparative Example 4) The polymer A and polymer B were weighed in a 10 / 90 mass ratio and then fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. Next, the polymer was ejected from the ejection orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of S / df = 0.11 and S ratio = 30%. In the post-ejection steps, except that the elongation ratio was set to 2.85 and the winding speed of the winding machine was set to 4150 m / min, all other conditions were the same as in Example 3 to obtain 56 dtex-24 count filaments. Although the obtained filaments were subjected to boiling water treatment, the shrinkage was weak and the stretchability was lacking. Furthermore, the elongation during moisture absorption and / or water absorption was reduced, causing discomfort during sweating. The evaluation results of the obtained fibers are shown in Table 5.

[0149] (Comparative Example 5) The spinning temperature was set to 270°C, and polybutylene terephthalate (melt viscosity 110 Pa·s, melting point 222°C) was used as polymer A, and polydecylamine (melt viscosity 160 Pa·s, melting point 220°C) was used as polymer B. The polymer A and polymer B were measured in a 50 / 50 mass ratio. The distribution plate of the composite spinneret shown in Figure 3 was changed, and the polymer was ejected from the ejection orifice (orifice diameter 0.23 mm, number of orifices 24) in a side-to-side cross-sectional shape with a simple bonding structure. The ejected composite polymer stream was cooled and solidified using a cooling device, and then a non-aqueous oil was supplied using an oil supply device. The circumferential speed of the traction roller belonging to the first roller was set to 1300 m / min, and the temperature was set to 90°C for traction. Next, the filaments drawn by the traction rollers were drawn again using the extension roller (second roller) with a surface temperature of 130°C. This resulted in an extension ratio of 2.54, expressed as the ratio of the circumferential speed of the traction rollers to that of the extension rollers. Simultaneously, heat treatment was performed using the extension roller. The heat-treated filaments were then wound using a winding machine at a winding speed of 3300 m / min to obtain 56 dtex-24 count extended yarn. Although the obtained extended yarn was subjected to boiling water treatment, the shrinkage was weak and the stretchability was lacking. Furthermore, the elongation during moisture absorption and / or water absorption was reduced, causing discomfort during sweating. Moreover, friction caused peeling at the interface between polymer A and polymer B in the fiber cross-section, resulting in partial white streaks, pilling, and other deterioration of fabric quality. The evaluation results of the obtained fibers are shown in Table 5.

[0150] (Comparative Example 6) Except for changing the distribution plate of the composite spinneret shown in Figure 3 to a concentric core sheath cross-section, 56 dtex-24 count extended filaments were obtained under the same conditions as in Example 13. Although the obtained extended filaments were subjected to boiling water treatment, no shrinkage was observed. The evaluation results of the obtained fibers are shown in Table 6.

[0151] (Comparative Example 7) Polyether ester amide (melt viscosity 50 Pa·s, melting point 200°C) containing 35% by mass of polydecylamine, 6% by mass of adipic acid, and 59% by mass of polyethylene glycol with a number average molecular weight of 1450 g / mol was used as polymer A, and polydecylamine (melt viscosity 50 Pa·s, melting point 220°C) was used as polymer B. Except that the polymers were measured in a 50 / 50 mass ratio of polymer A to polymer B, and the polymers were fed into the extrusion orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of 0.06 S / df and 48% S ratio, 56 dtex-24 count extended yarns were obtained under the same conditions as in Example 12. Although the obtained extended yarns were subjected to boiling water treatment, no shrinkage was observed. The evaluation results of the obtained fibers are shown in Table 6.

[0152] (Comparative Example 8) Except for changing the distribution plate of the composite spinneret shown in Figure 3 to a simple bonding structure with a side-to-side cross-sectional shape, 56 dtex-24 count filaments were obtained under the same conditions as in Example 13. Although the obtained filaments were subjected to boiling water treatment, the shrinkage was weak. Furthermore, because the hygroscopic polymer was exposed on the surface, it dissolved during hot water treatment, resulting in a decrease in the hygroscopicity of the fiber. The evaluation results of the obtained fibers are shown in Table 6.

[0153] (Comparative Example 9) The polymer A and polymer B were weighed in a 10 / 90 mass ratio and then fed into the spinneret assembly with the assembled composite spinneret shown in Figure 3. Next, the polymer was ejected from the ejection orifice (0.23 mm diameter, 24 orifices) with an eccentric core-sheath cross-section of S / df = 0.10 and S ratio = 28%. In the post-ejection steps, except that the circumferential speed of the traction roller was set to 1200 m / min and the elongation ratio was set to 2.75, all other conditions were the same as in Example 13 to obtain 56 dtex-24 count filaments. Although the obtained filaments were subjected to boiling water treatment, the shrinkage was weak and the stretchability was lacking. Furthermore, the elongation during moisture absorption and / or water absorption decreased, causing discomfort during sweating. Also, defects appeared inside the fibers during moisture absorption and / or water absorption, leading to a decrease in fabric quality. The evaluation results of the obtained fibers are shown in Table 6.

[0154] (Example 21) At a spinning temperature of 285°C, polybutylene terephthalate (melting viscosity 50Pa・s, melting point 217°C) copolymerized from 50 mass% of polyethylene glycol with a quantity average molecular weight of 8300 g / mol (Sanyo Chemical into industrial PEG6000S) was used as polymer A. After melting each polymer separately, it was measured in a mass ratio of 50 / 50 according to the composite ratio of polymer A to polymer B before it flowed into the jet assembly with the assembled composite jet nozzle shown in Figure 3 . The inflow polymer was then spit out from the spitting hole (pore size 0.23 mm, number of pores 24) in a manner that became an eccentric core sheath cross-sectional morphology with an S / df of 0.06 and an S ratio of 42%. The spitting composite polymer stream is cooled and cured using a cooling device, and the oil supply device is used to supply the non-water-containing oil agent. Traction was then applied by setting the circumferential rate of the traction roller belonging to the first roller to 2500m / min. Then, the strands that had been traction applied via traction rollers were traction using an extended roller belonging to the second roller with a circumferential rate of 2500m / min and a surface temperature of 25°C. The traction threads were applied by extension roller and curled using a winding machine with a curling speed of 2500m / min to obtain 84dtex-24 unextended threads. The obtained unextended threads were processed using a friction-type dummy processing machine at a processing rate of 1.50 times, a processing speed of 250m / min, a dummy number of 3000T / m, and a heater temperature of 170°C to obtain 56dtex-24 dummy processing threads. A boiling water treatment is applied to the obtained fake cock processing thread to show curling. The obtained coiled fibers were confirmed to have a coil-like coiled morphology in the fiber axis direction, a Dc / df of 7.5, and a coil pitch number of 4.5 pieces / mm. The evaluation results of the obtained coiled fibers are shown in Table 7 .

[0155] (Example 22) An unextended thread of 84 dtex-24 branches was obtained according to the same conditions as in Example 21 . The obtained unextended threads were processed using a friction-type dummy processing machine according to the processing magnification of 1.50 times, the processing speed of 250m / min, the number of dummy pins of 700T / m, and the heater temperature of 170°C to obtain 56dtex-24 dummy machining threads. A boiling water treatment is applied to the obtained fake cock processing thread to show curling. The obtained coiled fibers were confirmed to have a coil-like coiled morphology in the fiber axis direction, a Dc / df of 7.6, and a coil pitch number of 4.1 pieces / mm. The evaluation results of the obtained coiled fibers are shown in Table 7 .

[0156] (Example 23) 70 dtex-2 strands were obtained in accordance with the same conditions as in Example 21 except that the circumferential rate of the traction roller belonging to the 1st roller was set to 3500 m / min, the circumferential rate of the extended roller belonging to the 2nd roller was set to 3500 m / min, and the curling speed of the cylinder machine was set to 3500 m / min. The obtained unextended threads were processed using a friction-type dummy machine processing machine at a processing rate of 1.25 times, a processing speed of 250m / min, a dummy number of 3000T / m, and a heater temperature of 170°C to obtain 56dtex-24 dummy machining threads. A boiling water treatment is applied to the obtained fake cock processing thread to show curling. The obtained coiled fibers were confirmed to have a coil-like coiled morphology in the fiber axis direction, a Dc / df of 8.2, and a coil pitch number of 3.8 pieces / mm. The evaluation results of the obtained coiled fibers are shown in Table 7 .

[0157] (Compare Example 10) Unextended threads of 84 dtex-24 branches were obtained according to the same conditions as Example 21 . The obtained unextended threads were processed using a friction-type dummy processing machine at a processing rate of 1.50 times, a processing speed of 250m / min, a dummy number of 10000T / m, and a heater temperature of 170°C to obtain 56dtex-24 dummy processing threads. A boiling water treatment is applied to the obtained fake cock processing thread to show curling. Although the obtained coiled fibers have a coil-like coiled morphology in the fiber axis direction, the Dc / df is small and the coil pitch number is excessive. Also, the curl elongation is reduced when absorbing moisture and / or when absorbing water, and discomfort is felt during sweating and other conditions. Also, the cross-sectional deformation of the fiber during processing is larger, due to hot water treatment resulting in defects on the fiber surface, and the dissolution of the hygroscopic polymer, thus reducing the hygroscopicity. The evaluation results of the obtained fibers are shown in Table 7 . (Example 24) (Example 24) At a spinning temperature of 270°C, a polyether ester ester (melting viscosity 85Pa・s, melting point 200°C) containing polydeclamide 44 mass%, paraphthalate 6 mass%, and polyethylene glycol 50 mass% with a quantity average molecular weight of 1450 g / mol was used as polymer A. After each polymer was melted separately, it was measured in a mass ratio of 50 / 50 according to the composite ratio of polymer A to polymer B before it flowed into the jet assembly with the assembled composite jet nozzle shown in Figure 3 . Then, the inflow polymer was spit from the spitting hole (pore size 0.23 mm, number of pores 24) in a manner that became the cross-sectional morphology of an eccentric core sheath with an S / df of 0.06 and an S ratio of 45%. The spitting composite polymer stream is cooled and cured using a cooling device, and the oil supply device is used to supply the non-water-containing oil agent. Traction was then applied by setting the circumferential rate of the traction roller belonging to the first roller to 3500m / min. Then, the strands that had been traction applied through the traction roller were traction using an extended roller belonging to the second roller with a circumferential rate of 3500m / min and a surface temperature of 25°C. The strands that had been traction by extension roller were curled using a winding machine with a curling speed of 3500m / min to obtain 67dtex-24 unextended threads. The obtained unextended threads were processed using a friction-type dummy processing machine at a processing rate of 1.20 times, a processing speed of 400m / min, a dummy number of 4000T / m, and a heater temperature of 150°C to obtain 56dtex-24 dummy processing threads. A boiling water treatment is applied to the obtained fake cock processing thread to show curling. The obtained coiled fibers were confirmed to have a coil-like coiled morphology in the fiber axis direction, a Dc / df of 5.3, and a coil pitch number of 8.4 pieces / mm. The evaluation results of the obtained coiled fibers are shown in Table 8 .

[0159] (Example 25) An unextended thread of 67 dtex-24 branches was obtained in accordance with the same conditions as in Example 24 . The obtained unextended threads were processed using a friction-type dummy machine processing machine at a processing rate of 1.20 times, a processing speed of 400m / min, a dummy number of 680T / m, and a heater temperature of 150°C to obtain 56dtex-24 dummy machining threads. A boiling water treatment is applied to the obtained fake cock processing thread to show curling. The obtained coiled fibers were confirmed to have a coil-like coiled morphology in the fiber axis direction, a Dc / df of 5.7, and a coil pitch number of 8.2 pieces / mm. The evaluation results of the obtained coiled fibers are shown in Table 8 .

[0160] (Example 26) 44 dtex-2 threads were obtained in accordance with the same conditions as in Example 24, except that the circumferential rate of the traction roller belonging to the first roller was set to 4000 m / min, the circumferential rate of the extended roller belonging to the second roller was set to 4000 m / min, and the curling speed of the cylinder machine was set to 4000 m / min. The obtained unextended threads were processed using a friction-type dummy machine processing machine at a processing rate of 1.15 times, a processing speed of 400m / min, a dummy number of 3500T / m, and a heater temperature of 150°C to obtain 56dtex-24 dummy machining threads. A boiling water treatment is applied to the obtained fake cock processing thread to show curling. The obtained coiled fibers were confirmed to have a coil-like coiled morphology in the fiber axis direction, a Dc / df of 6.1, and a coil pitch number of 8.1 pieces / mm. The evaluation results of the obtained coiled fibers are shown in Table 8 .

[0161] (Compare Example 11) An unextended thread of 67 dtex-24 branches was obtained according to the same conditions as Example 24 . The obtained unextended threads were processed using a friction-type dummy machine processing machine at a processing rate of 1.20 times, a processing speed of 400 m / min, a dummy number of 8000 T / m, and a heater temperature of 150°C to obtain 56dtex-24 dummy machining threads. A boiling water treatment is applied to the obtained fake cock processing thread to show curling. Although the obtained coiled fibers had a coil-like coiled morphology in the fiber axis direction, the Dc / df was small and the coil pitch number was excess. Also, the curl elongation is reduced when absorbing moisture and / or when absorbing water, and discomfort is felt during sweating and other conditions. Also, there are defects within the fibers when absorbing moisture and / or when absorbing water, resulting in reduced fabric quality. The evaluation results of the obtained fibers are shown in Table 8 .

[0162] [Table 1] Table 1 Embodiment 1 Example 2 Example 3 Embodiment 4 Example 5 Example 6 Polymer A Polymer species PBT-PEG PBT-PEG PBT-PEG PBT-PEG PBT-PEG PBT-PEG Melt viscosity (Pa·s) 60 60 50 45 50 50 Polymer B polymer species PBT PBT PBT PET PBT PBT Melt viscosity (Pa·s) 110 110 240 150 240 240 Spinning conditions Melt viscosity ratio of polymer A to polymer B 1.8 1.8 4.8 3.3 4.8 4.8 The difference in melt viscosity between polymer A and polymer B (Pa・s) 50 50 190 105 190 190 Composite ratio of polymer A to polymer B 30 / 70 50 / 50 50 / 50 50 / 50 60 / 40 30 / 70 Polymer composite forms Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath S / df 0.06 0.06 0.06 0.06 0.06 0.06 S ratio (%) 35 45 42 42 46 33 Spinning temperature (°C) 270 270 285 290 285 285 Spinning Draft 63 63 73 145 76 68 Extension ratio 2.02 2.02 2.63 1.96 2.50 2.80 Fiber properties Fineness (dtex) 84 84 56 56 56 56 Single fiber fineness (dtex) 3.5 3.5 2.3 2.3 2.3 2.3 Strength (cN / dtex) 2.4 1.7 3.6 2.5 3.1 4.5 Elongation(%) 36 40 35 40 33 36 Initial tensile resistance (cN / dtex) 40 33 60 91 55 71 Shrinkage characteristics Coil diameter Dc (μm) 346.8 235.9 161.8 362.5 145.0 193.7 Single fiber diameter df (μm) 24.6 24.9 20.2 19.4 20.0 20.2 Dc / df 14.1 9.5 8.0 18.7 7.3 9.6 Number of coil pitches (per mm) 2.8 1.7 2.5 2.2 2.8 2.6 Elongation (%) 47 110 130 67 141 52 Elongation at break (%) 5 6 8 6 6 5 evaluate ΔMR (before hot water treatment) (%) 5.7 9.7 9.6 9.5 12.0 6.0 ΔMR (%) after hot water treatment 5.4 9.3 9.5 8.6 10.8 5.6 Change in ΔMR due to hot water treatment (%) -0.3 -0.4 -0.1 -0.9 -1.2 -0.4 Number of defects 1 2 0 5 3 1 Uneven staining (%) 1.3 0.9 1.1 2.2 1.5 1.0 Abrasion resistance (times) 3000 2800 3500 2700 3300 3700 Drying rate (min) 50 55 50 55 60 50 Antistatic properties (sec) 4.7 3.5 3.1 3.8 3.1 3.3 Clothing evaluation (heatiness) 3.9 4.0 4.5 4.2 4.4 4.3 PET: Polyethylene terephthalate PBT: Polybutylene terephthalate PBT-PEG: Polyethylene glycol copolymerized with polybutylene terephthalate

[0163] [Table 2] Table 2 Example 7 Example 8 Example 9 Example 10 Example 11 polymer A polymer species PBT-PEG PET-PEG PBT PBT-PEG PA-ES-PEG Melt viscosity (Pa·s) 50 68 240 50 70 polymer B polymer species PBT PBT PET-PEG PBT PBT Melt viscosity (Pa·s) 240 240 68 240 240 Spinning conditions Melt viscosity ratio of polymer A to polymer B 4.8 3.5 3.5 4.8 3.4 The difference in melt viscosity between polymer A and polymer B (Pa·s) 190 172 172 190 170 Composite ratio of polymer A to polymer B 50 / 50 60 / 40 30 / 70 50 / 50 50 / 50 Polymer composite forms Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath S / df 0.09 0.06 0.06 0.06 0.06 S ratio (%) 40 46 35 42 42 Spinning temperature (°C) 285 285 285 285 285 Spinning Draft 73 76 76 120 73 Extension ratio 2.63 2.50 2.50 2.38 2.63 Fiber properties Fineness (dtex) 56 56 56 56 56 Single fiber fineness (dtex) 2.3 2.3 2.3 1.6 2.3 Strength (cN / dtex) 3.6 3.4 2.6 3.4 3.4 Elongation(%) 37 36 38 37 35 Initial tensile resistance (cN / dtex) 60 42 75 43 62 Shrinkage characteristics Coil diameter Dc (μm) 256.3 146.2 55.3 107.3 138.4 Single-fiber diameter df (μm) 20.1 19.6 19.8 16.2 20.5 Dc / df 12.8 7.5 2.8 6.6 6.8 Number of coil pitches (per mm) 1.9 3.3 8.2 2.7 2.9 Elongation (%) 96 103 57 116 127 Elongation at break (%) 6 7 12 8 7 evaluate ΔMR (before hot water treatment) (%) 9.7 2.2 2.6 9.6 12.5 ΔMR (%) after hot water treatment 9.1 2.0 2.0 9.1 11.1 Change in ΔMR due to hot water treatment (%) -0.6 -0.2 -0.6 -0.5 -1.4 Number of defects 3 2 8 6 10 Uneven staining (%) 1.3 1.9 4.8 2.2 3.6 Abrasion resistance (times) 3800 3600 2600 2900 2700 Drying rate (min) 50 50 60 45 60 Antistatic properties (sec) 3.7 2.8 <1.0 2.9 3.0 Clothing evaluation (heatiness) 4.0 3.4 3.3 4.1 4.3 PBT: Polybutylene terephthalate PET-PEG: Polyethylene glycol copolymerized polyethylene terephthalate PBT-PEG: Polyethylene glycol copolymerized with polybutylene terephthalate PA-ES-PEG: Polyether ester amide

[0164] [Table 3] Table 3 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 polymer A polymer species PA-ES-PEG PA-ES-PEG PA-ES-PEG PA-ES-PEG PA-ES-PEG PA-ES-PEG Melt viscosity (Pa·s) 85 85 85 85 85 85 polymer B polymer species N6 N6 N6 N610 N6 N6 Melt viscosity (Pa·s) 40 40 160 100 40 40 Spinning conditions Melt viscosity ratio of polymer A to polymer B 2.1 2.1 1.9 1.2 2.1 2.1 The difference in melt viscosity between polymer A and polymer B (Pa·s) 45 45 75 15 45 45 Composite ratio of polymer A to polymer B 30 / 70 50 / 50 50 / 50 50 / 50 60 / 40 50 / 50 Polymer composite forms Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath S / df 0.06 0.06 0.06 0.06 0.06 0.09 S ratio (%) 33 43 45 43 46 40 Spinning temperature (°C) 270 270 270 270 270 270 Spinning Draft 70 81 81 81 86 81 Extension ratio 2.54 2.20 2.20 2.20 2.06 2.20 Fiber properties Fineness (dtex) 56 56 56 56 56 56 Single fiber fineness (dtex) 2.3 2.3 2.3 2.3 2.3 2.3 Strength (cN / dtex) 3.0 3.1 4.0 3.6 3.2 3.1 Elongation(%) 45 46 48 40 44 47 Alpha-type crystal alignment parameters 2.0 1.8 2.2 2.5 1.7 1.8 Shrinkage characteristics Coil diameter Dc (μm) 125.9 133.5 148.7 140.8 120.4 113.5 Single fiber diameter df (μm) 21.5 22.1 21.8 21.6 22.6 22.2 Dc / df 5.9 6.0 6.8 6.5 5.3 5.1 Number of coil pitches (per mm) 6.6 4.6 4.9 6.7 5.0 4.8 Elongation (%) 41 72 58 40 61 63 Elongation at break (%) 37 52 46 38 46 41 evaluate ΔMR (before hot water treatment) (%) 8.6 12.9 13.0 11.8 15.2 12.8 ΔMR (%) after hot water treatment 8.1 12.3 12.1 11.0 14.3 12.1 Change in ΔMR due to hot water treatment (%) -0.5 -0.6 -0.9 -0.8 -0.9 -0.7 Number of defects 5 0 7 4 8 3 Uneven staining (%) 1.1 0.7 1.3 1.0 1.4 1.2 Abrasion resistance (times) 4000 3900 4100 3600 3500 4000 Drying rate (min) 70 75 75 75 75 75 Antistatic properties (sec) 1.5 <1.0 <1.0 <1.0 <1.0 <1.0 Clothing evaluation (heatiness) 4.4 4.5 4.2 4.0 4.3 4.0 N6: Polydecylamine N610: Polyhexamethylene sebacamide PA-ES-PEG: Polyether ester amide

[0165] [Table 4] Table 4 Example 18 Example 19 Example 20 Polymer A polymer species PA-ES-PEG N6 PA-ES-PEG Melt viscosity (Pa·s) 55 160 85 Polymer B polymer species N6 N6+PVP N6 Melt viscosity (Pa·s) 45 130 40 Spinning conditions Melt viscosity ratio of polymer A to polymer B 1.2 1.2 2.1 The difference in melt viscosity between polymer A and polymer B (Pa·s) 10 30 45 Composite ratio of polymer A to polymer B 50 / 50 50 / 50 50 / 50 Polymer composite forms Eccentric core sheath Eccentric core sheath Eccentric core sheath S / df 0.06 0.06 0.06 S ratio (%) 43 46 43 Spinning temperature (°C) 260 270 270 Spinning Draft 81 70 86 Extension ratio 2.20 2.54 2.06 Fiber properties Fineness (dtex) 56 56 56 Single fiber fineness (dtex) 2.3 2.3 1.6 Strength (cN / dtex) 2.6 5.4 2.9 Elongation(%) 47 46 45 Alpha-type crystal alignment parameters 2.1 2.6 1.9 Shrinkage characteristics Coil diameter Dc (μm) 141.9 128.0 90.1 Single fiber diameter df (μm) 22.3 20.6 17.7 Dc / df 6.4 6.2 5.1 Number of coil pitches (per mm) 5.0 9.1 6.0 Elongation (%) 57 40 55 Elongation at break (%) 45 twenty one 39 evaluate ΔMR (before hot water treatment) (%) 13.1 3.0 13.1 ΔMR (%) after hot water treatment 12.3 2.7 11.8 Change in ΔMR due to hot water treatment (%) -0.8 -0.3 -1.3 Number of defects 3 0 6 Uneven staining (%) 1.1 0.8 1.1 Abrasion resistance (times) 4000 4000 3800 Drying rate (min) 75 70 75 Antistatic properties (sec) <1.0 <1.0 <1.0 Clothing evaluation (heatiness) 4.3 3.1 4.4 N6: Polydecylamine N6+PVP: Polyvinylpyrrolidone with added polycaprolactam PA-ES-PEG: Polyether ester amide

[0166] [Table 5] Table 5 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 polymer A polymer species PBT-PEG PBT-PEG PBT-PEG PBT-PEG PBT Melt viscosity (Pa·s) 50 50 45 45 110 polymer B polymer species PBT PBT PBT PBT N6 Melt viscosity (Pa·s) 240 50 240 240 160 Spinning conditions Melt viscosity ratio of polymer A to polymer B 4.8 1.0 5.3 5.3 1.5 The difference in melt viscosity between polymer A and polymer B (Pa·s) 190 0 195 195 50 Composite ratio of polymer A to polymer B 50 / 50 50 / 50 50 / 50 10 / 90 50 / 50 Polymer composite forms Concentric core sheath Eccentric core sheath Simply fit Eccentric core sheath Simply fit S / df - 0.06 - 0.11 - S ratio (%) - 43 - 30 - Spinning temperature (°C) 285 285 285 285 270 Spinning Draft 73 73 73 67 81 Extension ratio 2.63 2.63 2.63 2.85 2.54 Fiber properties Fineness (dtex) 56 56 56 56 56 Single fiber fineness (dtex) 2.3 2.3 2.3 2.3 2.3 Strength (cN / dtex) 3.6 3.0 3.4 5.3 5.1 Elongation(%) 36 33 37 36 39 Initial tensile resistance (cN / dtex) 62 54 55 116 43 Alpha-type crystal alignment parameters - - - - 2.2 Shrinkage characteristics Coil diameter Dc (μm) 0.0 0.0 30.2 41.3 38.9 Single fiber diameter df (μm) 20.5 19.8 20.1 21.3 20.0 Dc / df 0.0 0.0 1.5 1.9 1.9 Number of coil pitches (per mm) 0.0 0.0 0.4 0.6 0.5 Elongation (%) 0 0 13 36 41 Elongation at break (%) 0 0 3 2 4 evaluate ΔMR (before hot water treatment) (%) 9.7 9.4 9.2 2.2 1.1 ΔMR (%) after hot water treatment 9.1 7.2 4.3 2.0 1.0 Change in ΔMR due to hot water treatment (%) -0.6 -2.2 -4.9 -0.2 -0.1 Number of defects 13 26 35 5 35 Uneven staining (%) 4.0 5.8 10.3 3.0 4.1 Abrasion resistance (times) 3200 2000 2000 3500 2200 Drying rate (min) 60 50 70 50 60 Antistatic properties (sec) 4.5 5.1 <1.0 ≥120 ≥120 Clothing evaluation (heatiness) 2.9 2.8 2.6 2.3 2.0 PBT: Polybutylene terephthalate PBT-PEG: Polyethylene glycol copolymerized with polybutylene terephthalate N6: Polydecylamine

[0167] [Table 6] Table 6 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 polymer A polymer species PA-ES-PEG PA-ES-PEG PA-ES-PEG PA-ES-PEG Melt viscosity (Pa·s) 85 50 85 85 polymer B polymer species N6 N6 N6 N6 Melt viscosity (Pa·s) 40 50 40 40 Spinning conditions Melt viscosity ratio of polymer A to polymer B 2.1 1.0 2.1 2.1 The difference in melt viscosity between polymer A and polymer B (Pa·s) 45 0 45 45 Composite ratio of polymer A to polymer B 50 / 50 50 / 50 50 / 50 10 / 90 Polymer composite forms Concentric core sheath Eccentric core sheath Simply fit Eccentric core sheath S / df - 0.06 - 0.10 S ratio (%) - 48 - 28 Spinning temperature (°C) 270 270 270 270 Spinning Draft 81 70 81 65 Extension ratio 2.20 2.54 2.20 2.75 Fiber properties Fineness (dtex) 56 56 56 56 Single fiber fineness (dtex) 2.3 2.3 2.3 2.3 Strength (cN / dtex) 3.1 2.9 2.9 2.9 Elongation(%) 44 46 40 44 Alpha-type crystal alignment parameters 1.8 1.7 1.5 2.3 Shrinkage characteristics Coil diameter Dc (μm) 0.0 0.0 30.6 38.2 Single fiber diameter df (μm) 22.0 22.2 21.3 20.9 Dc / df 0.0 0.0 1.4 1.8 Number of coil pitches (per mm) 0.0 0.0 0.3 0.5 Elongation (%) 0 0 10 16 Elongation at break (%) 0 0 3 10 evaluate ΔMR (before hot water treatment) (%) 12.8 13.0 12.5 4.2 ΔMR (%) after hot water treatment 12.2 12.1 8.6 3.9 Change in ΔMR due to hot water treatment (%) -0.6 -0.9 -3.9 -0.3 Number of defects 25 11 31 4 Uneven staining (%) 4.8 4.0 9.3 2.1 Abrasion resistance (times) 3500 3300 2000 3500 Drying rate (min) 80 80 80 70 Antistatic properties (sec) 1.4 1.3 <1.0 2.6 Clothing evaluation (heatiness) 3.8 3.9 2.6 2.9 N6: Polydecylamine PA-ES-PEG: Polyether ester amide

[0168] [Table 7] Table 7 Example 21 Example 22 Example 23 Comparative Example 10 Polymer A polymer species PBT-PEG PBT-PEG PBT-PEG PBT-PEG Melt viscosity (Pa·s) 50 50 50 50 Polymer B polymer species PBT PBT PBT PBT Melt viscosity (Pa·s) 240 240 240 240 Spinning conditions Melt viscosity ratio of polymer A to polymer B 4.8 4.8 4.8 4.8 The difference in melt viscosity between polymer A and polymer B (Pa·s) 190 190 190 190 Complex ratio of polymer A / polymer B 50 / 50 50 / 50 50 / 50 50 / 50 Polymer composite morphology Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath S / df 0.06 0.06 0.06 0.06 S ratio (%) X. 42 42 42 42 Spinning temperature (°C) 285 285 285 285 Spun silk traction 129 129 155 129 Processing Conditions Processing rate 1.50 1.50 1.25 1.50 fake number (T / m) 3000 700 3000 10000 Fiber characteristics fiber (dtex) 56 56 56 56 single fiber fiber (dtex) 2.3 2.3 2.3 2.3 intensity (cN / dtex) 3.3 3.4 3.2 2.8 Elongation(%) 36 44 42 34 Initial tensile resistance (cN / dtex) 38 37 38 32 Shrinkage characteristics Coil diameter Dc (μm) 150.2 152.3 164.9 46.8 Single fiber diameter df (μm) 20.0 20.1 20.1 20.0 Dc / df 7.5 7.6 8.2 2.3 Number of coil pitches (per mm) 4.5 4.1 3.8 12.1 Elongation (%) 110 103 94 39 Elongation at break (%) 7 8 6 4 evaluate ΔMR (before hot water treatment) (%) 9.6 9.6 9.5 9.5 ΔMR (%) after hot water treatment 9.2 9.3 9.1 7.4 Change in ΔMR due to hot water treatment (%) -0.4 -0.3 -0.4 -2.1 Number of defects 3 5 8 26 Uneven staining (%) 1.1 1.3 2.6 4.2 Abrasion resistance (times) 3500 3200 3000 3000 Drying rate (min) 50 50 50 50 Antistatic properties (sec) 4.7 4.4 4.4 3.8 Clothing evaluation (heatiness) 4.3 4.1 4.0 2.4 PBT: Polybutylene terephthalate PBT-PEG: Polyethylene glycol copolymerized with polybutylene terephthalate

[0169] [Table 8] Table 8 Example 24 Example 25 Example 26 Comparative Example 11 Polymer A polymer species PA-ES-PEG PA-ES-PEG PA-ES-PEG PA-ES-PEG Melt viscosity (Pa·s) 85 85 85 85 Polymer B polymer species N6 N6 N6 N6 Melt viscosity (Pa·s) 160 160 160 160 Spinning conditions Melt viscosity ratio of polymer A to polymer B 1.9 1.9 1.9 1.9 The difference in melt viscosity between polymer A and polymer B (Pa·s) 75 75 75 75 Composite ratio of polymer A to polymer B 50 / 50 50 / 50 50 / 50 50 / 50 Polymer composite forms Eccentric core sheath Eccentric core sheath Eccentric core sheath Eccentric core sheath S / df 0.06 0.06 0.06 0.06 S ratio (%) 45 45 45 45 Spinning temperature (°C) 270 270 270 270 Spinning Draft 149 149 156 149 Processing conditions Processing ratio 1.20 1.20 1.15 1.20 fake number (T / m) 4000 680 3500 8000 Fiber characteristics fiber (dtex) 56 56 56 56 single fiber fiber (dtex) 2.3 2.3 2.3 2.3 intensity (cN / dtex) 4.1 4.2 4.0 3.4 elongation (%) 31 35 32 28 α-type crystal alignment parameters 2.1 2.1 2.0 2.1 Curling characteristics Coil diameter Dc (μm) 116.3 123.9 135.8 62.5 single fiber diameter df (μm) 22.0 21.9 22.3 22.1 Dc / df 5.3 5.7 6.1 2.8 Coil Pitch Number (pcs / mm) 8.4 8.2 8.1 16.0 Telescopic elongation (%) 61 58 57 23 Water absorption elongation (%) 34 30 35 10 evaluate ΔMR (before hot water treatment) (%) 12.8 12.7 12.8 12.9 ΔMR (%) after hot water treatment 12.0 12.1 11.9 11.4 Change in ΔMR due to hot water treatment (%) -0.8 -0.6 -0.9 -1.5 Number of defects 5 7 5 twenty two Uneven staining (%) 1.3 2.0 1.4 3.8 Abrasion resistance (times) 4000 4000 4000 3500 Drying rate (min) 70 70 70 75 Antistatic properties (sec) <1.0 <1.0 <1.0 <1.0 Clothing evaluation (heatiness) 4.5 4.3 4.3 2.9 N6: Polydecylamine PA-ES-PEG: Polyether ester amide (Industrial applicability)

[0170] The crimped fiber of this embodiment disperses the stress generated by the volume expansion of the fiber upon moisture absorption by utilizing the elongation of the crimp imparted to the composite fiber, thereby suppressing defects on the fiber surface or inside the fiber. Furthermore, when made into woven fabrics, the crimp elongates upon moisture absorption and / or water absorption, suppressing a decrease in the fabric's breathability and ensuring comfort even during sweating. Moreover, it retains excellent moisture absorption even after repeated use, and also possesses the stretchability necessary for movement control, making it particularly suitable for clothing applications requiring comfort.

[0171] The embodiments of the present invention have been described above, but the embodiments are not limited by the content of these embodiments. Furthermore, the aforementioned constituent elements include things that are readily conceived by those skilled in the art, substantially identical to them, and any equivalent range of things. Furthermore, the aforementioned constituent elements can be appropriately combined. Furthermore, the constituent elements can be omitted, substituted, or modified in various ways without departing from the spirit of the aforementioned embodiments. This application is based on Japanese Patent Application No. 2022-020215, filed on February 14, 2022, and its contents are incorporated herein by reference. [Simplified Explanation of the Diagram]

[0021] FIG1 is an example of a single fiber constituting the curled fiber of this embodiment, and is an observation diagram for illustrating the coil diameter of the curled shape. In FIG2, FIG2(a) to FIG2(c) are schematic cross-sectional views of the fiber of the curled fiber of this embodiment. FIG3 is a cross-sectional view for illustrating the manufacturing method of the curled fiber of this embodiment.

Claims

1. A coiled fiber, a composite fiber composed of two polymers, polymer A and polymer B, having a coiled shape along the fiber axis, wherein the ratio of the coil diameter Dc to the single fiber diameter df, Dc / df, is 2.0 or more and 20.0 or less, the number of coil pitches is 1.0 or more / mm and 10.0 or less, polymer A is completely covered by polymer B in the fiber cross-section, and the moisture absorption / desorption parameter ΔMR is 2.0% or more; wherein polymer B is an aromatic polyester; and the initial tensile resistance is 10 cN / dtex or more and 100 cN / dtex or less.

2. As in claim 1, the curled fiber, wherein, Of the two polymers mentioned above, polymer A has higher hygroscopicity.

3. As in claim 1, the curled fiber, wherein, The two polymers mentioned above have the same type of bond in the main backbone of the repeating unit that constitutes each of the two polymers.

4. The curled fiber as requested in item 1, wherein, The composite morphology of the fiber cross section is an eccentric core-sheath cross section that satisfies the following requirements: (1) The ratio of the minimum thickness S of polymer B to the single fiber diameter df, S / df, is 0.01 or more and 0.10 or less. (2) The portion having a thickness of 1.05 times or less than the minimum thickness S, and the portion having a thickness of 30% or more of the circumference of the cross-section of the surrounding long fiber.

5. A fiber article which uses the curled fiber of any one of claims 1 to 4.

6. A coiled fiber, a composite fiber composed of two polymers, polymer A and polymer B, having a coiled shape along the fiber axis, wherein the ratio of the coil diameter Dc to the single fiber diameter df, Dc / df, is 2.0 or more and 20.0 or less, the number of coil pitches is 1.0 or more / mm and 10.0 or less, polymer A is completely covered by polymer B in the fiber cross-section, and the moisture absorption / desorption parameter ΔMR is 2.0% or more; wherein polymer B is an aliphatic polyamide; and the α-type crystal alignment parameter of the polyamide of polymer B is 1.7 or more and 2.6 or less.

7. A fiber article that uses the crimped fiber of claim 6.

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