Crimped fibers

Abstract

The present invention relates to crimped fibers that are composite fibers formed from two kinds of polymers A and B and are characterized in that the crimped fibers have a coil-shaped crimped form in the fiber axis direction, the ratio Dc / df between the coil diameter Dc and the single fiber diameter df is 2.0-20.0, the coil pitch number is 1.0-10.0 per 1 mm, the polymer A is fully covered with the polymer B in the fiber cross section, and the moisture absorbing and releasing parameter ΔMR is 2.0% or more.

Description

Crimped fiber

[0001] The present invention relates to a crimped fiber having moisture-absorbing properties.

[0002] Synthetic fibers made from thermoplastic resins such as polyamide and polyester are widely used in clothing and industrial applications due to their excellent mechanical properties, chemical resistance, heat resistance, and other characteristics. Polyamide fibers, such as polycapramide and polyhexamethylene adipamide, have unique softness, high tensile strength, colorability when dyed, high heat resistance, and excellent moisture absorption. Polyester fibers, such as polyethylene terephthalate, have a characteristic firm and resilient texture, little change in properties when wet, and excellent quick-drying properties, wrinkle resistance, and dimensional stability. Taking advantage of their excellent properties, these synthetic fibers are widely used in clothing applications such as innerwear and sportswear.

[0003] As people desire a more comfortable life, they are demanding ever more advanced properties from textile materials. Therefore, efforts are being made to improve the sophistication of textile materials to achieve the desired comfort. Generally, the level of comfort in clothing varies depending on the environment and atmosphere in which the material is used. Among these factors, maintaining an appropriate environment between clothing and the skin, i.e., the space inside clothing, is an important factor directly linked to comfort.

[0004] The temperature and humidity levels within clothing at which people feel comfortable are limited, making it important to adjust them appropriately. In particular, there is a strong demand for moisture-wicking properties in clothing materials to prevent stuffiness and stickiness, which tend to occur in hot, humid summer environments. However, polyamide fibers do not have sufficient moisture-wicking properties compared to natural fibers such as cotton, and hydrophobic polyester fibers, depending on the weave, can cause stuffiness and stickiness, reducing comfort.

[0005] Therefore, it has been proposed to improve the moisture absorption by forming a composite fiber with a hygroscopic polymer. For example, Patent Document 1 proposes a sea-island composite fiber in which a hygroscopic polymer is used in the island portions to impart moisture absorption to the fiber, and the thickness of the polyester in the sea portion present in the outermost layer of the fiber cross section is controlled, thereby suppressing cracking of the polyester in the sea portion during hot water treatment.

[0006] Patent Document 2 proposes a sheath-core composite fiber that is composed of a core and a sheath, and has a shape in which the core is not exposed on the fiber surface, and in which the core is made of a polyether block amide copolymer whose hard segment is nylon 6, and the sheath is made of nylon 6 resin.

[0007] Another proposed method for suppressing stuffiness inside clothing is to produce woven or knitted fabrics using fibers with a crimped structure, thereby changing the crimping pattern during moisture absorption and release, thereby adjusting the breathability of the fabric. The stress generated by the volumetric swelling of hygroscopic polymers during moisture absorption can be dispersed by elongating the crimp of the fibers in the fiber axis direction, thereby improving the durability of hygroscopic synthetic fibers.

[0008] For example, Patent Document 3 proposes a crimped composite fiber in which a polyamide component and a polyester component containing a water-swellable polyether ester polymer are bonded side by side.

[0009] Furthermore, Patent Document 4 proposes a water-repellent woven or knitted fabric that exhibits improved breathability upon absorbing moisture, and that includes a conjugated fiber having a crimped structure in which a polyester component and a polyamide component are bonded side-by-side and the crimp rate differs between dry and wet.

[0010] Furthermore, as a method for suppressing stuffiness inside clothing, it has been proposed to impart water absorbency by the crimped structure of fibers. For example, Patent Document 5 proposes moisture-absorbing and desorbing crimped yarn, which is a synthetic fiber having crimps composed of a moisture-absorbing and desorbing component and a fiber-forming polymer.

[0011] International Publication No. 2018 / 012318 International Publication No. 2014 / 10709 Japanese Patent Application Laid-Open No. 2009-114581 Japanese Patent Application Laid-Open No. 2006-97176 Japanese Patent Application Laid-Open No. 11-279871

[0012] The conjugate fibers described in Patent Documents 1 and 2 have high moisture absorption performance. However, the hygroscopic polymer in the island and core portions swells in volume upon moisture absorption. Therefore, when these fibers are processed into yarn and the fiber cross section changes significantly, stress generated by the volumetric swelling of the hygroscopic polymer can cause cracks and other breaks on the fiber surface, delamination of the polymer between the sea portion and the island portion or between the sheath portion and the core portion, and voids in the hygroscopic polymer in the island and core portions.

[0013] When cracks or other breaks appear on the fiber surface or when polymers separate between the sea and island regions or between the sheath and core regions, uneven dyeing or fuzzing can occur, degrading the quality of woven or knitted fabrics. Also, moisture absorption can be reduced by elution of the moisture-absorbing polymer. Furthermore, volumetric swelling of the moisture-absorbing polymer can increase the fiber diameter, reducing the gaps between the fibers that make up the fabric, thereby reducing breathability and comfort.

[0014] The side-by-side composite fibers disclosed in Patent Documents 3 and 4 have a simple bonded structure. As a result, they have low crimping performance, and the morphological change of the fibers upon moisture absorption may be insufficient. The volumetric swelling of the moisture-absorbing polymer increases the fiber diameter, reducing the voids between the fibers constituting the fabric, thereby reducing breathability and comfort. Furthermore, because they have a simple bonded structure, friction and impact can easily cause peeling at the interface, potentially resulting in partial white streaks and fuzzing, which can degrade the fabric quality. Furthermore, because the moisture-absorbing polymer is exposed to the fiber surface, the moisture-absorbing polymer is easily eluted, and the loss of moisture absorption with repeated use can be a problem in practical applications.

[0015] The crimped yarn described in Patent Document 5 is crimped by yarn processing such as false twisting, forced crimping, fluid forced crimping using a heated fluid, etc. As a result, the crimping performance is low, the morphological change of the fiber may be insufficient, and the volumetric swelling of the hygroscopic polymer increases the fiber diameter, reducing the gaps between the fibers that make up the fabric, thereby reducing breathability and comfort.

[0016] The present invention aims to solve the above problems, and has as its object the provision of a crimped fiber that has excellent moisture absorption properties, is capable of suppressing deterioration in quality due to cracks and other breakages on the fiber surface upon moisture absorption, peeling of polymers between the sea and island regions or between the sheath and core regions, and voids in the moisture-absorbing polymers in the island and core regions, and is capable of providing excellent comfort when made into woven or knitted fabrics.

[0017] As a result of extensive research, the present inventors have come up with the idea of ​​improving the durability of moisture-absorbing synthetic fibers by dispersing the stress generated by the volumetric swelling of a moisture-absorbing polymer upon moisture absorption, for example, by elongating the crimp of the fiber in the fiber axis direction. Specifically, the present invention provides a crimped fiber that can suppress defects on the fiber surface or inside by dispersing the stress generated by the volumetric swelling of the fiber upon moisture absorption through elongation of the crimp imparted to the composite fiber. Furthermore, when made into woven or knitted fabrics, the crimp elongates upon moisture and / or water absorption, thereby suppressing a decrease in the breathability of the fabric and maintaining comfort even when sweating, and further provides a crimped fiber whose moisture absorption does not decrease with repeated use.

[0018] In order to solve the above problems, the present invention has the following configurations. (1) A crimped fiber, which is a conjugate fiber made of two polymers, polymer A and polymer B, and has a coiled crimped morphology in the fiber axis direction, a ratio Dc / df of the coil diameter Dc to the single fiber diameter df of 2.0 to 20.0, a coil pitch number of 1.0 / mm to 10.0 / mm, polymer A being completely covered with polymer B in the fiber cross section, and a moisture absorption / desorption parameter ΔMR of 2.0% or more. (2) The crimped fiber according to (1) above, in which the polymer with the higher moisture absorption of the two polymers is polymer A. (3) The crimped fiber according to (1) above, in which the two polymers have the same type of bond in the main skeleton constituting the repeating units of each of the two polymers. (4) A textile product using the crimped fiber according to any one of (1) to (3) above.

[0019] According to the present invention, it is possible to obtain crimped fibers with excellent moisture absorption properties. Furthermore, by dispersing the stress generated by volumetric swelling of the fiber upon moisture absorption through the elongation of the crimp imparted to the composite fiber, it is possible to obtain crimped fibers that suppress defects occurring on the fiber surface or inside the fiber. Furthermore, when the crimped fibers of the present invention are made into woven or knitted fabrics, the crimps elongate upon moisture absorption and / or water absorption, thereby suppressing a decrease in breathability of the fabric and preventing a loss of comfort even when sweating. Furthermore, the fibers retain excellent moisture absorption properties even with repeated use, and also possess the stretch performance necessary for movement tracking, making them particularly suitable for use in clothing applications where comfort is required.

[0020] Fig. 1 is an example of a single fiber constituting the crimped fiber of this embodiment, and is an observation diagram for explaining the coil diameter in the crimped form. Fig. 2(a) to Fig. 2(c) are schematic diagrams of fiber cross sections of the crimped fiber of this embodiment. Fig. 3 is a cross-sectional view for explaining the manufacturing method of the crimped fiber of this embodiment.

[0021] The present invention will be described in detail below. The following description is an example of the present invention, and the present invention is not limited thereto. In this specification, a statement expressed as "to" indicates a range including the numbers before and after it. In this specification, "mass" and "weight" have the same meaning.

[0022] The crimped fiber of this embodiment is a conjugated fiber made of two polymers and has excellent moisture absorption properties with a moisture absorption / desorption parameter ΔMR of 2.0% or more, thereby providing a fiber structure that is excellent in wear comfort as a cooling material.

[0023] As described above, the crimped fiber of this embodiment has a moisture absorption / desorption parameter ΔMR, which is an index of moisture absorption, of 2.0% or more. Here, ΔMR is the difference in the moisture absorption rate of a fiber at high temperature and humidity, typically at 30°C and 90% relative humidity, and at standard temperature and humidity, typically at 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 is 2.0% or more, the stuffiness inside clothing made from the crimped fiber of this embodiment is reduced, improving wearing comfort. A more preferable ΔMR range is 4.0% or more. In this case, since the fiber can retain more moisture, in addition to suppressing the stuffiness, excellent antistatic properties, for example, are also exhibited. An even more preferable ΔMR range is 6.0% or more. Since the fiber can retain even more moisture, when made into a fabric, it quickly absorbs water vapor and provides a cool-to-the-touch feel. This characteristic is effective from the viewpoint of wearing comfort, and if the moisture absorption performance is further improved to a value of 8.0% or more, stuffiness and stickiness can be suppressed even in a high-temperature, high-humidity environment in summer, and this can be cited as a particularly preferable range.

[0024] Although there is no particular upper limit to the range of ΔMR, the level that can be achieved in this embodiment is about 17%, which is the substantial upper limit. That is, ΔMR may be 17% or less. Furthermore, the crimped fibers of this embodiment satisfy the above ΔMR range both before and after hot water treatment such as dyeing.

[0025] Moisture-absorbing fibers incorporate water molecules through physical adsorption and / or interactions between water molecules and functional groups in the molecular structure of the fiber components. High hygroscopicity, in particular, results in significant volumetric swelling due to the incorporation of many water molecules into the fiber. Generally, when moisture-absorbing fibers undergo volumetric swelling, they are less likely to elongate along the fiber axis, and instead expand primarily in the direction perpendicular to the fiber axis, i.e., in the direction of increasing the cross-sectional area of ​​the fiber. However, fibers composed of polymers with rigid aromatic rings in the main backbone of the repeating units, such as aromatic polyesters, are less likely to deform, and the stress generated during volumetric swelling due to moisture absorption cannot be fully dispersed, resulting in cracks on the fiber surface. Furthermore, fibers composed of flexible polymers with low glass transition temperatures, such as aliphatic polyamides and polyolefins, can experience delamination of the polymers between the sea and island regions or between the sheath and core regions, or the formation of voids in the polymers constituting the island and core regions, due to deformation associated with moisture-induced volumetric swelling.

[0026] Therefore, in the crimped fiber of this embodiment, which suppresses defects that occur on the fiber surface or inside the fiber due to volumetric swelling upon moisture absorption, it is important that the crimped fiber has a coiled crimp morphology in the fiber axis direction. The coiled crimp morphology referred to here includes, for example, a three-dimensional spiral crimp that occurs when the single fibers constituting the crimped fiber are curved in response to the difference in shrinkage between two polymers upon heat treatment, and the shape of the single fiber is similar to that of a coil spring as defined in JIS B 0103:2012 (Spring Terminology).

[0027] Because the crimped fiber of this embodiment has a coil spring shape, twisting occurs in the fiber axis direction of the single fiber. Therefore, when the volume expands due to moisture absorption, a force acts on the single fiber in the twist direction, starting from this twist, allowing it to elongate and deform in the fiber axis direction. This elongation reduces the expansion deformation in the area expansion direction of the fiber cross section, further improving the durability of the crimped fiber. Furthermore, when made into a fiber structure such as a fabric, the crimped fiber elongates and deforms in the fiber axis direction upon moisture absorption and / or water absorption, maintaining the breathability of the fabric and providing comfort when worn. Furthermore, when moisture is released and / or drying is performed, a force acts on the single fiber in the untwist direction, returning it to its shape before moisture absorption and / or water absorption, allowing the same deformation to occur even with repeated use. In addition, the crimped fiber can be elongated and deformed in the fiber axis direction by an external force, thereby providing the stretch performance necessary for a fiber structure such as a fabric to follow the wearer's movements.

[0028] As an index for determining the coiled crimp morphology in the fiber axis direction of the crimped fiber of this embodiment, it is important to control the ratio Dc / df of the coil diameter Dc to the single fiber diameter df. The larger Dc / df, the softer the coiled crimp morphology becomes, and the easier it is to elongate and deform. In other words, the stress generated by volumetric swelling upon moisture absorption can be dispersed by elongation of the crimp. Furthermore, the soft coiled crimp morphology exhibits functions such as appropriate stretchability when made into fabrics such as woven fabrics and knitted fabrics, resulting in a bouncy feel and a soft, fluffy texture.

[0029] On the other hand, the smaller the Dc / df, the harder the coiled crimped form becomes and the less susceptible it is to elongation deformation, but the shape stability of the crimped form improves, so the crimped form can be maintained even after repeated moisture absorption and desorption. Furthermore, because the shape of the coiled crimped form is stable, when the fabric is made, the twisting of the crimped fibers causes the crimped form to become entangled with adjacent fibers, creating voids between the fibers. The capillary phenomenon of the resulting fine interfiber voids creates functions such as water absorption, which, combined with the moisture absorption properties of the crimped fiber of this embodiment, results in a fiber structure that is excellent in wear comfort as a cooling material. In addition, because the shape of the coiled crimped form is stable, it also exhibits the ability to follow the wearer's movements.

[0030] As a result of intensive study based on these findings, the crimped fiber of this embodiment has a ratio Dc / df of the coil diameter Dc to the single fiber diameter df of 2.0 or more and 20.0 or less. By setting Dc / df to 2.0 or more, the coil-shaped crimped form is more easily elongated and deformed, and the stress generated by volumetric swelling upon moisture absorption can be dispersed by elongation of the crimp. Furthermore, when the crimped fiber of this embodiment is made into a fabric such as a woven fabric or knitted fabric, functions such as appropriate stretchability are exhibited, and a bouncy feel and a soft, fluffy texture are obtained. On the other hand, by setting Dc / df to 20.0 or less, the coil-shaped crimped form is stabilized, and the crimped form can be maintained even after repeated moisture absorption and desorption. Furthermore, functions such as water absorption due to capillary action in the fine inter-fiber voids exhibited by the coil-shaped crimped form are exhibited, and a fiber structure with excellent wear comfort as a cooling material can be obtained. Dc / df is preferably 4.0 or more and 18.0 or less, and more preferably 6.0 or more and 16.0 or less.

[0031] The coil diameter Dc in this embodiment is a value measured by observing a single fiber separated from the crimped fiber of this embodiment two-dimensionally from the side (direction perpendicular to the fiber axis direction) and measuring peaks and valleys alternately observed in the fiber width direction 3 as illustrated in FIG. 1 .

[0032] Specifically, the fiber sample to be evaluated is cut into a 10 m skein using a measuring machine or the like, and immersed in boiling water at 98 ° C or higher under a load of 0.2 mg / d for 15 minutes. The boiling water-treated yarn is thoroughly dried by air drying, and then a load of 2 mg / d is applied for 30 seconds or more, after which a marking is made at any point on the yarn bundle so that the distance between two points is 3 cm. Thereafter, single fibers are separated from the yarn bundle without plastic deformation, and the distance between the pre-marked marks is adjusted to the original 3 cm, and the sample is fixed on a slide glass. An image of this sample is taken with a microscope (e.g., a digital microscope manufactured by KEYENCE) at a magnification that allows 5 to 10 crimp peaks to be observed. In the photographed image (Fig. 1), the apexes of any adjacent peaks in the fiber width direction 3 are designated as M1 and M2, and the apex of the valley between M1 and M2 is designated as V. The shortest distance (µm) (reference numeral 1 in Fig. 1) between the line connecting M1 and M2 and V is measured to two decimal places. The same operation is performed on different randomly selected single fibers, and by repeating this, the shortest distance is measured so that the total number of data points is 50. The simple number average of the 50 shortest distances is calculated, and the value rounded to one decimal place is the coil diameter Dc (µm).

[0033] The single fiber diameter df in this embodiment is a value calculated by the following method. Specifically, a fiber sample is embedded in an embedding agent such as epoxy resin, and images of the fiber cross section perpendicular to the fiber axis are taken with a scanning electron microscope (e.g., a scanning electron microscope (SEM) manufactured by Hitachi) at a magnification such that 10 or more single fibers can be observed. The diameter of a single fiber (denoted by reference numeral 8 in Figure 2(b)) randomly selected within each image is measured in μm units to two decimal places. This procedure is performed for 10 randomly selected single fibers, and the simple number average of the results is calculated, rounded to one decimal place, to obtain the single fiber diameter df (μm). If the fiber cross section perpendicular to the fiber axis is not a perfect circle, the area of ​​the obtained image is measured using, for example, computer software WinROOF manufactured by Mitani Corporation, and the value obtained by converting it into a circle having the same area is used.

[0034] In the crimped fiber of this embodiment, the coiled crimped form in the fiber axis direction has a coil pitch number of 1.0 or more / mm and 10.0 or less / mm. The coil pitch number here is a factor that determines the amount of elongation deformation of the coiled crimped form. That is, by setting the coil pitch number to 1.0 or more / mm, a sufficient number of coiled crimped forms are present per unit length, thereby enabling the elongation deformation necessary to disperse the stress generated by volumetric swelling upon moisture absorption. Furthermore, the presence of a sufficient number of coiled crimped forms allows the formation of fine interfiber voids when the fiber is made into a fiber structure such as a fabric, thereby providing functionality such as water absorption. Furthermore, by setting the coil pitch number to 10.0 or less / mm, the amount of elongation deformation when a certain stress is generated is large, and when the fiber is made into a fiber structure such as a fabric, breathability can be maintained due to the elongation deformation of the crimped fibers caused by moisture and / or water absorption. In addition, the fiber structure exhibits appropriate stretchability, resulting in a material with excellent wearing comfort. The coil pitch number is preferably 1.5 pieces / mm or more and 9.0 pieces / mm or less, and more preferably 2.0 pieces / mm or more and 8.0 pieces / mm or less.

[0035] The coil pitch number of the crimped fiber of this embodiment is calculated as follows. Using an image taken when measuring the coil diameter Dc, the distance (mm) between any two adjacent crimp peaks M1 and M2 in the coiled crimped form (reference numeral 2 in FIG. 1) is determined to two decimal places. This procedure is performed at three arbitrary locations per single fiber, and this is repeated for ten different single fibers. The reciprocal of the simple number average of these measurement results is calculated, and the value rounded to one decimal place is used as the coil pitch number (numbers / mm).

[0036] The crimped fiber of this embodiment has a cross section made up of two types of polymers, and the polymers used here are preferably fiber-forming thermoplastic polymers.

[0037] The crimped fiber of this embodiment has excellent moisture absorption properties, and therefore can be used, for example, as an innerwear fiber in clothing applications that are close to the wearer's skin. In the case of innerwear, other clothing made of different materials may be worn over it. When layered in this way, friction between the innerwear and the other clothing can generate static electricity, which can impair the wearer's comfort. Therefore, the crimped fiber of this embodiment preferably has a half-life of 10 seconds or less at a temperature of 20°C and a relative humidity of 40%, as measured according to JIS L1094 (Test Methods for Electrostatic Charge of Woven and Knit Fabrics, 2014) Method A (Half-Life Measurement Method).

[0038] The half-life is the time it takes for the electrostatic voltage to decrease to 50% of the initial electrostatic voltage after a specific voltage is applied to a fabric sample, and is an index of the ease with which static electricity generated in the fabric can be released, i.e., its antistatic properties.

[0039] If the half-life at a temperature of 20°C and a relative humidity of 40% is 10 seconds or less, the antistatic properties of the crimped fiber of this embodiment are good, and static electricity generated by friction when wearing layers can be easily released, making it possible to wear clothing made from the crimped fiber of this embodiment comfortably. The half-life at a temperature of 20°C and a relative humidity of 40% is more preferably 5 seconds or less.

[0040] The crimped fiber of this embodiment has a composite structure in which two polymers, polymer A and polymer B, are bonded together in the cross section of the fiber, and it is important that polymer A is completely covered with polymer B. Here, "polymer A is completely covered with polymer B" means that polymer A is not exposed on the surface of the crimped fiber in the cross section of the fiber, and polymer B is continuously formed.

[0041] FIG. 2(a) shows an example of a fiber cross section of a crimped fiber of this embodiment. In FIG. 2(a), polymer component 5, indicated by the horizontal haunch, is polymer B, and polymer component 4, indicated by the 30-degree haunch (diagonal lines pointing upward to the right), is polymer A. As shown in FIG. 2(a), polymer A is completely covered by polymer B and is not exposed on the surface of the crimped fiber. Because polymer A is completely covered by polymer B, durability at the interface between the two polymers can be improved even when the fiber deforms due to volumetric swelling upon moisture absorption. Furthermore, even when friction or impact is applied to the fiber or fabric, peeling at the interface between the two polymers is unlikely to occur, thereby suppressing whitening and fuzzing, and maintaining good fabric quality. Additionally, components that would be exposed to the surface of a composite fiber and cause defects in a simple bonded structure, such as high-molecular-weight polymers, highly elastic polymers, and polymers with low heat resistance or abrasion resistance, can also be used as one of the components of the composite fiber.

[0042] Suitable polymers for achieving the object of this embodiment include aromatic polyesters typified by polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, etc., aliphatic polyesters typified by polylactic acid, aliphatic polyamides typified by polycapramide, polyhexamethylene adipamide, etc., semi-aromatic polyamides typified by polyhexamethylene terephthalamide, thermoplastic elastomers typified by thermoplastic polyurethane, polyolefins typified by polypropylene, etc. In general, from the viewpoints of mechanical properties, heat resistance, and ease of handling during production, it is preferable to use aromatic polyesters or aliphatic polyamides.

[0043] The aromatic polyesters described above are high molecular weight polymers having repeating units linked via ester bonds to a main chain formed from a combination of an aromatic dicarboxylic acid and an aliphatic diol, an aliphatic dicarboxylic acid and an aromatic diol, or an aromatic dicarboxylic acid and an aromatic diol. Among these, aromatic polyesters formed from an aromatic dicarboxylic acid and an aliphatic diol are preferred. Examples of such aromatic dicarboxylic acids include, but are not limited to, terephthalic acid, isophthalic acid, phthalic acid, 5-sodium sulfoisophthalic acid, 5-(tetraalkyl)phosphonium sulfoisophthalic acid, 4,4'-diphenyldicarboxylic acid, and 2,6-naphthalenedicarboxylic acid. Examples of such aliphatic diols include, but are not limited to, ethylene glycol, 1,3-propanediol, 1,4-butanediol, hexanediol, cyclohexanediol, diethylene glycol, hexamethylene glycol, and neopentyl glycol.

[0044] When aromatic polyester is used in the crimped fiber of this embodiment, the fiber has high rigidity, and therefore the crimped shape can be maintained even if the crimped fiber is repeatedly stretched and deformed due to moisture absorption and release. Furthermore, when made into a fabric, a firm and resilient texture can be obtained. Furthermore, since aromatic polyester generally does not have functional groups in the polymer structure that form strong interactions with water molecules, crimped fibers and fabrics with excellent quick-drying properties can be obtained.

[0045] The aliphatic polyamides are high molecular weight polymers having repeating units in which hydrocarbon groups are linked to the main chain via amide bonds. They are generally synthesized by polycondensation reactions using aminocarboxylic acids or cyclic amides as raw materials, or by polycondensation reactions using dicarboxylic acids and diamines as raw materials. Examples of such polyamides include, but are not limited to, polycapramide, polyundecanolactam, polylauryllactam, polyhexamethylene adipamide, polyhexamethylene sebacamide, and polyhexamethylene dodecanediamide.

[0046] When aliphatic polyamides are used in the crimped fibers of this embodiment, they have moisture absorption properties due to the amide bonds in the repeating units and the amino groups bonded to the terminals of the polymer structure, resulting in crimped fibers with very high moisture absorption. Furthermore, aliphatic polyamides generally have a low glass transition temperature, which is a polymer characteristic, and are highly flexible, making the crimped fibers more susceptible to elongation and deformation due to moisture and / or water absorption, which makes it easier to achieve the effect of further enhancing the durability of the crimped fibers of this embodiment. Furthermore, when made into fabrics, the very high moisture absorption properties provide a cool feel to the touch. Additionally, the low glass transition temperature provides a soft texture.

[0047] The method for producing the polymer in this embodiment is not limited, and if the raw materials used in production are collectively referred to as monomers, the monomers may be synthesized by a general polycondensation reaction, addition polymerization reaction, or the like. Examples of monomers include, but are not limited to, petroleum-derived monomers, biomass-derived monomers, mixtures of petroleum-derived monomers and biomass-derived monomers, and recycled monomers obtained by reusing polymers as raw materials using chemical recycling techniques. Alternatively, polymers may be produced using material recycling techniques from waste materials such as waste plastics. Furthermore, the polymer in this embodiment may be copolymerized or mixed with a second component and a third component in addition to the main component, as long as the purpose of the present invention is not deviated from.

[0048] As described above, the crimped fiber of this embodiment has a moisture absorption / desorption parameter ΔMR, which is an index of moisture absorption, of 2.0% or more. Examples of methods for adjusting ΔMR of the crimped fiber of this embodiment to fall within the above range include adding a moisture-absorbing compound, arranging a polymer with high moisture absorption (hereinafter, sometimes referred to as a moisture-absorbing polymer), and treating polymer molecules on the fiber surface with ozone or the like to generate moisture-absorbing functional groups. Among these, when it is intended to obtain crimped fibers with excellent moisture absorption, it is preferable to use a moisture-absorbing polymer.

[0049] Examples of suitable hygroscopic polymers for use in the crimped fibers of this embodiment include polyetheresters, polyetheramides, polyetheresteramides, polyamides, thermoplastic cellulose derivatives, polyvinylpyrrolidone, etc. Among these, polyetheresters, polyetheramides, and polyetheresteramides containing polyether as a copolymerization component are preferred because they have excellent stability during melt molding and have the desired high hygroscopicity.

[0050] Polyetherester is a block copolymer containing ester and ether bonds in the polymer structure. Specifically, it is a block copolymer obtained by polycondensation of polyester-forming components consisting of dicarboxylic acids and diols, and polyalkylene glycol components.

[0051] The combination of polyester-forming components and polyalkylene glycol components is not limited, but a preferred example is a polyether ester in which polyethylene glycol is copolymerized with an aromatic polyester composed of an aromatic dicarboxylic acid and an aliphatic diol as a polyester-forming component, from the viewpoint of the heat resistance of the hygroscopic polymer. More preferred is a polyether ester composed of polybutylene terephthalate and polyethylene glycol, which has excellent crystallinity, because it can suppress the elution of the hygroscopic polymer in hot water.

[0052] Polyetheramide is a block copolymer having an amide bond and an ether bond in the polymer structure, specifically a block copolymer obtained by polycondensation of one or more polyamide-forming components selected from lactam, aminocarboxylic acid, and salts of diamine and dicarboxylic acid, and a polyalkylene glycol component.

[0053] The combination of the polyamide-forming component and the polyalkylene glycol component is not particularly limited, but preferred examples include, as the polyamide-forming component, lactams such as ε-caprolactam, ω-aminocarboxylic acids such as aminocaproic acid, and nylon salts of diamine-dicarboxylic acids, which are precursors to polyhexamethylene adipamide, polyhexamethylene sebacamide, etc., and as the polyalkylene glycol component, polyethylene glycol. From the viewpoints of heat resistance, fiber-forming ability, and moisture absorption of the hygroscopic polymer, more preferred is a polyether amide in which ε-caprolactam is used as the polyamide-forming component and polyethylene glycol is copolymerized.

[0054] Furthermore, polyetheresteramide is a block copolymer having ether bonds, ester bonds, and amide bonds in the polymer structure. Specifically, it is a block copolymer obtained by polycondensation reaction of one or more polyamide-forming components selected from lactam, aminocarboxylic acid, and salts of diamine and dicarboxylic acid, and a polyetherester component consisting of dicarboxylic acid and polyalkylene oxide glycol.

[0055] The combination of the polyamide-forming component and the polyether ester component is not limited, but preferred examples of the polyamide-forming component include those exemplified in the polyether amide described above. Furthermore, the polyalkylene glycol component constituting the polyether ester component may include polyethylene glycol from the viewpoint of hygroscopicity, and the dicarboxylic acid may include adipic acid, sebacic acid, dodecadiacetic acid, terephthalic acid, and isophthalic acid.

[0056] The hygroscopic polymer in the crimped fiber of this embodiment may be copolymerized or mixed with a second component and a third component in addition to the main component, within the scope of the object of the present invention, and the copolymerization amount is preferably 10 mol % or less as the amount of copolymerized monomers relative to the total amount of monomers.

[0057] The above-mentioned hygroscopic polymers have a high affinity for water and are easily eluted when they come into contact with water or hot water during dyeing. If the hygroscopic polymer elutes to the outside of the fiber, the hygroscopicity of the fiber may decrease. Therefore, in the crimped fiber of this embodiment, it is preferable that the above-mentioned hygroscopic polymer is completely covered by polymer B exposed on the surface layer of the fiber in the cross section of the fiber, i.e., that the hygroscopic polymer is disposed as polymer A. By not exposing the hygroscopic polymer to the surface layer of the fiber, it is possible to prevent the hygroscopic polymer from coming into contact with hot water and eluting to the outside of the fiber. Furthermore, the coil-like crimped form that the crimped fiber of this embodiment has in the fiber axis direction significantly enhances the durability of the crimped fiber, resulting in a crimped fiber with excellent hygroscopicity.

[0058] The combination of two polymers constituting the crimped fiber of this embodiment is not particularly limited, but is preferably selected from a combination of polymers that have high affinity and are easily mixed together. A combination of polymers with high affinity promotes entanglement of molecular chains at the polymer interface, thereby suppressing interfacial peeling between the two polymers. Furthermore, the ability to conform to deformation of the fiber is improved, preventing accumulation of deformation strain on the fiber surface or inside the fiber, and further increasing the durability of the crimped fiber.

[0059] In such a combination of polymers, it is preferable that the main skeleton constituting the repeating unit of each of the two polymers has the same type of bond. Examples of the bond here include an amide bond, an ester bond, an ether bond, a urea bond, and a urethane bond. In other words, having the same type of bond in the main skeleton constituting the repeating unit of each of the two polymers means, for example, that if the repeating unit of polymer A has an amide bond, the repeating unit of polymer B also has an amide bond. Similarly, if the repeating unit of polymer A has an ester bond, the repeating unit of polymer B also has an ester bond.

[0060] When a moisture-absorbing polymer is used 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 moisture-absorbing 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 moisture-absorbing polymer. These combinations ensure high affinity between the two polymers, thereby improving durability at the interface between the two polymers. Furthermore, the stress generated by volumetric swelling of the fiber upon moisture absorption can be dispersed by the extension of the crimp imparted to the composite fiber, preventing accumulation of deformation strain on the fiber surface or inside the fiber, thereby further improving the durability of the crimped fiber.

[0061] The combination of polymers with high affinity can also be selected based on the solubility parameters (SP values) of the two polymers. The SP value is defined as (evaporation energy / molar volume). １ / ２ The closer these values ​​are, the higher the affinity of the polymer combination is. This SP value is known for various polymers, and is described, for example, on page 189 of "Plastics Data Book" (co-edited by Asahi Kasei Amidas Co., Ltd. and Plastics Editorial Department, 1999).

[0062] In this embodiment, the difference in the SP values ​​of the two selected polymers is 4 (MJ / m ３ ) １ / ２ If the difference in SP value between the two selected polymers is less than 3 (MJ / m), the two polymers will have good adhesive strength. ３ ) １ / ２ More preferably, 2 (MJ / m ３ ) １ / ２ The following is the result.

[0063] A preferred example of the combination of polymers for achieving the objectives of the present invention is, when polymer A or polymer B is an aromatic polyester, polyethylene terephthalate and polyetherester (a copolymer of polyethylene terephthalate and polyethylene glycol), polyethylene terephthalate and polyetherester (a copolymer of polybutylene terephthalate and polyethylene glycol), or polybutylene terephthalate and polyetherester (a copolymer of polybutylene terephthalate and polyethylene glycol). Among these, a combination in which polyetherester (a copolymer of polybutylene terephthalate and polyethylene glycol) is used as polymer A and polybutylene terephthalate is used as polymer B is preferred. In this case, because polymer B is flexible and easily deformed polybutylene terephthalate, even if the fiber volume swells upon moisture absorption, the stress dispersion effect due to the crimp morphology is combined with the deformation of polymer B, thereby further enhancing the durability of the surface layer of the crimped fiber. Furthermore, because both polymer A and polymer B have a polybutylene terephthalate structure, no deformation strain accumulates at the interface where polymer A and polymer B contact, thereby further enhancing the durability of the crimped fiber.

[0064] Furthermore, examples of suitable combinations when polymer A or polymer B is an aliphatic polyamide include polycapramide and polyetheresteramide (a copolymer of polycapramide and polyethylene glycol having adipic acid bonded to the terminal), polycapramide and polyetheresteramide (a copolymer of polycapramide and polyethylene glycol having terephthalic acid bonded to the terminal), polyhexamethyleneadipamide and polyetheresteramide (a copolymer of polycapramide and polyethylene glycol having terephthalic acid bonded to the terminal), polyhexamethylenesebacamide and polyetheresteramide (a copolymer of polycapramide and polyethylene glycol having terephthalic acid bonded to the terminal), polycapramide and polyvinylpyrrolidone-added polycapramide, etc. Among these, a combination in which polyetheresteramide (a copolymer of polycapramide and polyethylene glycol having terephthalic acid bonded to the terminal) is arranged in polymer A and polycapramide is arranged in polymer B is preferred. In this case, since polymer B is a hygroscopic polycapramide, crimped fibers having both excellent hygroscopic performance and mechanical properties can be obtained. Furthermore, since polycapramide is also a flexible and easily deformable polymer, even if the fiber swells in volume upon absorbing moisture, the stress dispersion effect due to the crimped form is combined with the deformation of polymer B, thereby further enhancing the durability of the surface layer of the crimped fiber. Furthermore, since both polymer A and polymer B have a polycapramide structure, the durability of the interface where polymer A and polymer B come into contact can be further enhanced.

[0065] When the crimped fiber of this embodiment is made of an aliphatic polyamide, the aliphatic polyamide has excellent flexibility due to its low glass transition temperature, which is a polymer characteristic of the aliphatic polyamide. This makes it particularly susceptible to deformation, and the amount of deformation is large. When the crimped fiber is repeatedly stretched and deformed due to moisture and / or water absorption, or when the crimped fiber is deformed by an external force, it is preferable to further increase the durability of the crimped fiber. From this perspective, when the crimped fiber of this embodiment is made of an aliphatic polyamide, particularly when polymer B is an aliphatic polyamide, it is preferable that the α-crystal orientation parameter of polymer B, the polyamide, be 1.7 or more and 2.6 or less.

[0066] The α-crystals of polyamides are stable crystals that form when high stress is applied. When the α-crystal orientation parameter of the polyamide (polymer B) is 1.7 or higher, the polyamide is highly crystallized, resulting in excellent crimped fiber durability. Therefore, even when the crimped fibers are stretched and deformed due to moisture and / or water absorption, or when the crimped fibers are deformed by external forces, they exhibit good durability. On the other hand, when the α-crystal orientation parameter of the polyamide is 2.6 or lower, the polyamide is not too crystallized, resulting in a flexible coiled crimped form that facilitates stretching and deformation. Furthermore, water molecules can permeate the fibers, resulting in excellent moisture absorption performance. When polymer B is an aliphatic polyamide, the α-crystal orientation parameter of the polyamide (polymer B) is more preferably 1.8 or higher and 2.5 or lower.

[0067] The composite form of the two polymers in the cross section of the crimped fiber of this embodiment is not particularly limited, except that polymer A is completely covered with polymer B. However, in order to achieve the object of the present invention, it is preferable that the cross section be an eccentric core-sheath cross section in which the position of the center of gravity of polymer A is different from the center of the cross section of the fiber.

[0068] The position of the center of gravity of polymer A referred to here is point a in Figure 2(a), and the center of the fiber cross section is point c in Figure 2(a). In the crimped fiber of this embodiment, the center of gravity a of polymer A is separated from the center c of the fiber cross section, allowing the fiber to have a three-dimensional spiral structure and favorably exhibit a coiled crimp morphology in the fiber axis direction. Furthermore, when the crimped fiber of this embodiment has an eccentric core-sheath cross section, it is preferable that both of the following requirements be satisfied: (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 circumferential length of the portion having a thickness within 1.05 times the minimum thickness S is 30% or more of the circumference of the fiber cross section (hereinafter sometimes referred to as the S ratio).

[0069] The minimum thickness S of polymer B covering polymer A is determined as follows. Specifically, the crimped fiber of this embodiment is embedded in an embedding agent such as epoxy resin as a bundle, and an image of the cross section of this fiber is taken using a transmission electron microscope (TEM) at a magnification that allows observation of 10 or more fibers. If metal dyeing is applied, the dye difference between the polymers can be utilized to clearly show the contrast at the junction between polymer A and polymer B. A single fiber is randomly selected from the image, and an arbitrary point E at the interface between polymer A and polymer B is selected as shown in Figure 2(b). A tangent line 6 to point E at the interface is then drawn. Next, a perpendicular line to the tangent line is drawn from point E toward 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 designated as the thickness (μm) (reference numeral 7 in Figure 2). This was repeated for 10 single fibers randomly sampled within the same image, and the simple number average of the thicknesses was calculated. The value was rounded to two decimal places and defined as the minimum thickness S (μm). Furthermore, using the image where the minimum thickness S was measured, the single fiber diameter df (μm) was measured by the above method. Using the obtained S and df, S / df was calculated by rounding to two decimal places.

[0070] The eccentric core-sheath cross section of the composite morphology satisfies the above requirements, allowing the distance between the center of gravity a of polymer A and the center c of the fiber cross section to be freely set, resulting in a favorable coiled crimp morphology in the fiber axis direction. This allows for sufficient elongation and deformation of the crimp to be generated in order to disperse the stress generated by volumetric swelling upon moisture absorption. Furthermore, the coiled crimp morphology allows for functionality such as water absorption and moderate stretchability to be exhibited when the composite is made into a fiber structure such as a fabric, resulting in a material with excellent wear comfort.

[0071] The cross-sectional shape of the crimped fiber of this embodiment can be not only a round cross-section, but also a wide variety of cross-sectional shapes such as flat, Y-shaped, T-shaped, hollow, rice paddy, and well-shaped.

[0072] The crimped fibers of this embodiment may be in any form, such as long fibers (filaments) or short fibers (staples). In the case of long fibers, they may be monofilaments consisting of one single yarn or multifilaments consisting of multiple single yarns. In the case of short fibers, there are no limitations on the cut length or the number of crimps.

[0073] The fineness of the crimped fibers of this embodiment may be appropriately set depending on the application, but for long fibers for clothing, a fineness of 8 dtex or more and 150 dtex or less is practically preferred.

[0074] Furthermore, the strength is preferably 1.5 cN / dtex or more for clothing, but by taking measures such as combining it with other fibers when producing a fabric, it can be used without any problems even if it is 1.5 cN / dtex or less.

[0075] The elongation may be appropriately set depending on the application, but is preferably 25% or more and 60% or less from the viewpoint of processability when processed into a fabric. When post-processing described below is performed, it is preferable to set the elongation of the fiber before post-processing to 60% or more and 250% or less.

[0076] The crimped fiber of this embodiment preferably has a single fiber fineness of 8.0 dtex or less. By setting the single fiber fineness within this range, the hardness of the coil-shaped crimped form can be reduced, resulting in a fiber structure that is excellent in mechanical properties and heat resistance, and in addition, has moderate stretchability and is therefore comfortable to wear. Furthermore, the stress generated by volumetric swelling upon moisture absorption can be dispersed by elongation of the crimp, preventing accumulation of deformation strain on the fiber surface or inside the fiber, resulting in excellent quality when made into a woven or knitted fabric. The single fiber fineness is more preferably 5.0 dtex or less, and even more preferably 3.0 dtex or less.

[0077] When the crimped fiber of this embodiment is made of an aromatic polyester, the rigidity of the fiber is increased due to the molecular structure, and therefore the crimped shape can be maintained. On the other hand, if the crimp becomes hard, the crimped fiber will deform elastically when it is stretched and deformed due to moisture and / or water absorption, or when an external force is applied, and therefore it is preferable to increase the durability to such repeated deformation.

[0078] From this viewpoint, if polymer A or polymer B is an aromatic polyester, the crimped fiber of this embodiment preferably has an initial tensile resistance of 10 cN / dtex or more and 100 cN / dtex or less. The initial tensile resistance is measured by the method described in Section 8.10 of the Testing Methods for Chemical Fiber Filament Yarns (JIS L1013 (2010)), and is correlated with the apparent Young's modulus, i.e., indicates the ease of deformation of the fiber.

[0079] If the initial tensile resistance is 10 cN / dtex or more, the coil-shaped crimped form has rigidity, so that the crimp does not collapse even when stretched and deformed, and after stretching and deformation due to moisture and / or water absorption, the original crimped form can be restored by releasing moisture and / or drying.On the other hand, if the initial tensile resistance is 100 cN / dtex or less, the stiffness of the coil-shaped crimped form can be reduced, and stress generated by volumetric swelling upon moisture absorption can be dispersed by stretching the crimp, so that deformation strain does not accumulate on the fiber surface or inside the fiber, resulting in excellent quality when made into a woven or knitted fabric.

[0080] The crimped fibers of this embodiment can be obtained by known melt spinning and conjugated spinning techniques, examples of which are as follows: However, the spinning method and conjugation method are not limited to those exemplified here.

[0081] Methods for producing the crimped fibers of this embodiment made of two polymers include melt spinning, which is intended to produce long fibers; wet and dry-wet solution spinning; and melt-blowing and spunbonding, which are suitable for obtaining sheet-like fiber structures. Among these, melt spinning is preferred from the viewpoint of increasing productivity. When using melt spinning, the spinning temperature is set to a temperature at which the polymers used, primarily those with high melting points or high viscosity, exhibit fluidity. The temperature at which this fluidity exhibits varies depending on the molecular weight, but is preferably set between the melting point of the polymer and melting point + 60°C, as this allows for stable production.

[0082] In a melt spinning method, for example, polymer A and polymer B are melted separately, metered and transported using a gear pump, and a composite flow is formed using a known method to form a specific composite structure, which is then discharged from a spinneret. The discharged yarn is cooled to room temperature by blowing cooling air onto it using a yarn cooling device such as a chimney, and then oiled and focused using an oiling device. The focused yarn is entangled using a fluid entanglement nozzle device and passed through a take-up roller and a stretching roller. During this process, the yarn is stretched according to the ratio of the peripheral speeds of the take-up roller and the stretching roller. Further, the yarn is heat-set using a stretching roller and wound up using a winder (winding device). Another example is a two-step method in which the peripheral speeds of the take-up roller and the stretching roller are set to the same, and the unstretched yarn is then wound up using a winder operating at the same speed, resulting in an unstretched yarn, which is then stretched in a separate step.

[0083] In the crimped fiber of this embodiment, it is preferable to set the melt viscosity ratio of the two polymers (polymer with high melt viscosity / polymer with low melt viscosity) to less than 5.0, because this allows a stable formation of a composite polymer flow and enables the production of fibers with a good composite cross section.

[0084] In view of the object of the present invention, a combination of polymers that causes a difference in shrinkage upon heat treatment is preferred, and the difference in melt viscosity between the two polymers to be combined is preferably 10 Pa·s or more.

[0085] The composite spinneret used to produce the crimped fiber of this embodiment is preferably the composite spinneret described in JP 2011-208313 A. The composite spinneret shown in Fig. 3 is assembled into a spin pack in a stacked state consisting of three main components, from top to bottom: a metering plate 9, a distributor plate 10, and a discharge plate 11, and is used for spinning. With conventional composite spinnerets, it is difficult to control the composite cross-sectional shape as described above, and therefore it is preferable to use a composite spinneret that utilizes fine flow channels as shown in Fig. 3.

[0086] In the spinneret member exemplified in FIG. 3, the metering plate 9 measures and introduces the amount of polymer per discharge hole and per distribution hole, the distribution plate 10 controls the composite cross section and cross-sectional shape of the single fiber, and the discharge plate 11 compresses the composite polymer flow formed by the distribution plate 10 and discharges it.

[0087] Although not shown in the drawings to avoid complicating the explanation of the composite spinneret, members having flow paths formed thereon in accordance with the spinning machine and spin pack can be used for the members stacked above the metering plate 9. By designing the metering plate 9 in accordance with existing flow path members, the existing spin pack and its members can be used as they are, so there is no need to dedicate a spinning machine specifically to the spinneret.

[0088] Furthermore, multiple flow path plates may be stacked between the flow path and the metering plate 9 or between the metering plate 9 and the distributor plate 10. This provides a flow path for efficiently transporting the polymer in the cross-sectional direction of the spinneret and the cross-sectional direction of the single fiber, and allows the polymer to be introduced into the distributor plate 10. The composite polymer stream discharged from the discharge plate 11 is cooled and solidified according to the above-described production method, and then an oil is applied thereto. The composite polymer stream is taken up by a roller set at a specified peripheral speed, thereby obtaining a fiber having a desired composite cross section. When the composite form of the crimped fiber of this embodiment has an eccentric core-sheath cross section, it is particularly preferable to use the above-described composite spinneret from the viewpoint of stable cross section formation.

[0089] In the crimped fiber of this embodiment, the conjugation ratio of polymer A to polymer B is preferably 70 / 30 to 20 / 80 in terms of the ratio of polymer A mass / polymer B mass. By setting the ratio within this range, differences in orientation occur between the two polymers in the spinning and drawing processes, resulting in differences in shrinkage during heat treatment, making it possible to obtain fibers with excellent crimp properties. Furthermore, when a hygroscopic polymer is used as polymer A, the ΔMR and antistatic properties can be controlled within specific ranges for the crimped fiber of this embodiment. The ratio of polymer A mass / polymer B mass is more preferably 60 / 40 to 30 / 70.

[0090] In the production of crimped fibers of this embodiment, the spinning draft, which is expressed by the speed ratio between the linear discharge speed of the spinneret and the take-up roller (take-up roller speed / linear discharge speed of the spinneret), is preferably 10 or more and less than 300. The linear discharge speed of the spinneret here is the discharge volume per unit time of the polymer discharged from the holes in the discharge plate 11 of the composite spinneret divided by the cross-sectional area of ​​the discharge holes of the spinneret.

[0091] This spinning draft is correlated with the orientation of the fibers that occurs from the time the fibers are discharged from the holes in the discharge plate 11 of the composite spinneret, cooled, and taken up by the take-up rollers, and the larger the spinning draft, the greater the orientation of the fibers that occur before being taken up by the take-up rollers. Furthermore, when the crimped fiber of this embodiment is made of two polymers with different melt viscosities, an orientation difference occurs between the two polymers, which in turn causes a shrinkage difference during heat treatment, and therefore a fiber with excellent crimp properties can be obtained.

[0092] If the spinning draft is less than 300, the tension applied to the polymer immediately after discharge from the composite spinneret can be reduced, and thread breakage due to excessive tension before being taken up by the take-up roller can be suppressed. Furthermore, if the spinning draft is 10 or more, sufficient fiber orientation is obtained, and differences in orientation between the two polymers are likely to occur, which also makes it easier for differences in shrinkage during heat treatment to occur, thereby improving crimp properties. The spinning draft is more preferably 30 or more and less than 150.

[0093] In the production of the crimped fiber of this embodiment, when heat setting is performed on rollers after drawing, it is preferable to perform the heat treatment under tension and then cool the fiber to a temperature below the glass transition point while maintaining the tension. By performing the tension heat treatment and tension cooling treatment to fix the structure of the polymer molecular chains of the fiber, it is possible to increase the shrinkage stress, which is effective in controlling the ratio Dc / df of the coil diameter Dc to the single fiber diameter df and the coil pitch number within a specific range for the crimped fiber of this embodiment.

[0094] The crimped fiber of this embodiment may be crimped not only by utilizing the difference in thermal shrinkage between the polymers as described above, but also by post-processing such as false twisting or twisting. More preferably, the fiber has both crimp structures. This is because, by subjecting the fiber to twisting in addition to crimping due to the difference in thermal shrinkage between the polymers, two types of crimp morphology are mixed, and the ratio Dc / df of the coil diameter Dc to the single fiber diameter df and the coil pitch number can be controlled within a specific range for the crimped fiber of this embodiment.

[0095] For example, the false twisting method is not particularly limited as long as it is a method commonly used for polyamides, polyesters, etc., but considering productivity, it is preferable to use a friction false twisting machine using a disk or belt. In order to stably produce the crimped fiber of this embodiment by false twisting, it is preferable to control the crimp form by the number of actual twists in the twisting region. In other words, it is preferable to set the false twisting conditions, such as the rotation speed of the twisting mechanism and the processing speed, so as to satisfy the following conditions: 5000 / Fi ０．５ ≦T≦40000 / Fi ０．５

[0096] Here, T is the false twist number, which indicates the number of twists (turns / m) in the twisting region, and Fi is the total fineness (dtex) of the textured yarn after false twisting. The false twist number T is measured by the following method. The textured yarn running in the twisting region of the false twisting process is sampled to a length of 50 cm or more so as not to untwist just before the twister. The sampled yarn sample is then attached to a twist detector, and the number of twists measured using the method described in JIS L1013 (2010) 8.13 is the false twist number T. If the false twist number T satisfies the above conditions, the crimp morphology can be controlled, and not only can deterioration of fabric quality such as wrinkles and streaks be suppressed, but the intended effects of the present invention can also be achieved.

[0097] The fiber structure made of the crimped fiber and / or post-processed yarn of this embodiment may have any woven or knitted structure, and plain weave, twill weave, satin weave, or variations thereof, warp knitting, weft knitting, circular knitting, lace knitting, or variations thereof, etc. can be suitably used.

[0098] The crimped fiber of this embodiment may be combined with other fibers by interweaving or interknitting when being made into a fiber structure, or may be made into a blended yarn with other fibers and then used as a fiber structure.

[0099] The fiber structure made of the crimped fiber and / or post-processed yarn of this embodiment has excellent moisture absorption properties and can therefore be suitably used in applications requiring comfort and quality, such as, but not limited to, general clothing, sportswear, bedding, interior decoration, and materials.

[0100] As explained above, the present specification discloses the following configurations. <1> A crimped fiber, which is a conjugate fiber made of two polymers, polymer A and polymer B, and has a coiled crimped morphology in the fiber axis direction, a ratio Dc / df of the coil diameter Dc to the single fiber diameter df of 2.0 to 20.0, a coil pitch number of 1.0 to 10.0 coils / mm, polymer A being completely covered with polymer B in the fiber cross section, and a moisture absorption / desorption parameter ΔMR of 2.0% or more. <2> The crimped fiber according to <1>, in which of the two polymers, polymer A is the more hygroscopic polymer. <3> The crimped fiber according to <1> or <2>, in which 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 textile product using the crimped fiber according to any one of <1> to <3>.

[0101] The present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. The respective property values ​​in the examples were measured using the following methods.

[0102] A. Melt Viscosity of Polymer A polymer sample whose moisture content was reduced to 300 ppm or less using a vacuum dryer was placed in a heating furnace set at the same temperature as the spinning temperature, and melted under a nitrogen atmosphere using a Toyo Seiki Capillograph. The sample was extruded from the capillary at the tip of the heating furnace while changing the strain rate stepwise, and the viscosity was measured. The sample was allowed to remain in the heating furnace for 5 minutes after being placed in the furnace, and the measurement was started at a shear rate of 1216 sec. －１ The value at this point was taken as the melt viscosity of the polymer.

[0103] B. Melting point (Tm) of polymer Using a differential scanning calorimeter (DSC) Model Q2000 manufactured by TA Instruments, 20 mg of a 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, cooled from 280°C to 20°C at a heating rate of 20°C / min, held at 20°C for 1 minute, and then heated from 20°C to 280°C at a heating rate of 20°C / min. The peak top temperature of the endothermic peak observed when this was done was taken as the melting point. When multiple endothermic peaks were observed, the top of the endothermic peak with the highest temperature was taken as the melting point.

[0104] C. Fineness A fiber sample was wound 200 times on a measuring machine with a frame circumference of 1.125 m to prepare a skein, and after drying in a hot air dryer (105±2°C x 60 minutes), the mass of the skein was measured on a balance and multiplied by the official moisture regain to calculate the fineness. The measurement was performed four times, and the average value was taken as the fineness.

[0105] D. Strength and Elongation Fiber samples were measured using a "TENSILON" (registered trademark) UCT-100 manufactured by Orientec Co., Ltd. as a measuring instrument under the constant-rate elongation conditions specified in the chemical fiber filament yarn testing method (JIS L1013 (2010)). The elongation was determined from the elongation at the point showing the maximum strength in the tensile strength-elongation curve. The strength was calculated by dividing the maximum strength by the fineness. The measurement was performed 10 times, and the average values ​​were used as the strength and elongation.

[0106] E. ΔMR (ΔMR before hot water treatment) Approximately 1 to 2 g of a fiber sample or fabric sample was weighed into a weighing bottle, dried at 110°C for 2 hours, and then the mass was measured. ０ Next, the dried fiber sample was kept at a temperature of 20°C and a relative humidity of 65% for 24 hours, and then the mass was measured. ６５％ Subsequently, the temperature was adjusted to 30°C and the relative humidity to 90%, and the fiber sample was kept there for 24 hours, after which the mass was measured. ９０％ MR １ = [(w ６５％ -w ０ ) / w ０ ]×100...(1) MR ２ = [(w ９０％ -w ０ ) / w ０]×100...(2) ΔMR=MR ２ -MR １ (3) At this time, the value calculated using the formulas (1) to (3) was taken as ΔMR.

[0107] F. ΔMR after hot water treatment A cylindrical knitted fabric was produced from the fiber sample using an Eiko Sangyo NCR-BL circular knitting machine (boiler diameter 3.5 inches (8.9 cm), 27 gauge) with a stitch count adjusted to 50. When the fiber fineness was less than 80 dtex, the fibers were appropriately combined so that the total fineness of the fibers fed to the cylindrical knitting machine was 80 to 160 dtex. When the total fineness exceeded 80 dtex, only one yarn was fed to the cylindrical knitting machine. Next, the obtained cylindrical knitted fabric was placed in an aqueous solution containing 1 g / L sodium carbonate and the surfactant Sunmol BK-80 manufactured by Nicca Chemical. The aqueous solution was heated to 80°C and treated for 20 minutes, and then dried in a hot air dryer at 60°C for 60 minutes. The dried cylindrical knit fabric was then subjected to hot water treatment in water with a mass 100 times the mass of the cylindrical knit fabric at a treatment temperature of 130°C for 60 minutes, and then dried for 60 minutes in a hot air dryer at 60°C to obtain a cylindrical knit fabric after hot water treatment. ΔMR was calculated for the obtained cylindrical knit fabric after hot water treatment in accordance with the description in Section E.

[0108] G. Coil diameter Dc A fiber sample was cut into a 10 m skein using a measuring instrument or the like, and immersed in boiling water at 98 ° C or higher under a load of 0.2 mg / d for 15 minutes. After thoroughly drying the boiling water-treated yarn by air drying, a load of 2 mg / d was applied for 30 seconds or more, and then markings were made at any point on the yarn bundle so that the distance between the two points was 3 cm. Then, single fibers were separated from the yarn bundle to prevent plastic deformation, and the distance between the pre-marked marks was adjusted to the original 3 cm and fixed on a glass slide. Images of this sample were taken using a KEYENCE digital microscope at a magnification that allowed 5 to 10 crimp peaks to be observed. In each captured image, the vertices of any adjacent peaks were designated M1 and M2, and the vertex of the valley between M1 and M2 was designated V. The shortest distance D (μm) between the line connecting M1 and M2 and V was measured to two decimal places. The same operation was performed on different randomly selected single fibers, and by repeating this, the shortest distance D was measured so that the total number of data points was 50. The simple number average of the 50 measured shortest distances D was calculated, and the value rounded to one decimal place was taken as the coil diameter Dc (μm).

[0109] H. Single Fiber Diameter df The fiber sample treated in section G was embedded in an embedding medium such as epoxy resin, and images of the fiber cross section perpendicular to the fiber axis were taken using a Hitachi scanning electron microscope (SEM) at a magnification sufficient to observe 10 or more single fibers. From each image, the diameter of a randomly selected single fiber within the same image was measured in μm units to three decimal places. This procedure was repeated for 10 randomly selected single fibers. The simple number average of the measurement results was calculated, and the value rounded to two decimal places was used as the single fiber diameter df (μm). If the fiber cross section perpendicular to the fiber axis was not a perfect circle, the image was analyzed using computer software WinROOF (Mitani Shoji) to measure its area, and the value obtained by converting it to a circle with the same area was used. Images for measurement may also be taken using a transmission electron microscope (TEM).

[0110] I. Coil Pitch Number Using the image taken when measuring the coil diameter Dc in item G, the distance (mm) between any two adjacent crests M1 and M2 in the coiled crimped form was measured to two decimal places at any three points per single fiber, and this measurement was performed on 10 different single fibers. The reciprocal of the simple number average of the results was calculated, and the value rounded to one decimal place was used as the coil pitch number (pcs / mm).

[0111] J. Stretching and Elongation Rate Using a measuring machine with an appropriate tension adjustment device, a fiber sample was wound into a skein with 10 turns. The treatment temperature was selected in accordance with JIS L1013 (2010) Section 6, and a load of 0.2 mg / d was applied for wet heat treatment. Then, treatment was carried out in accordance with JIS L1013 (2010) Section 8.11, Method C (simplified method), to determine the stretching and elongation rate.

[0112] K. Water Absorption Elongation A fiber sample is wound into a skein with 10 turns using a measuring machine with an appropriate tension adjustment device. The treatment temperature is selected in accordance with JIS L1013 (2010) Section 6, and a moist heat treatment is performed with a load of 0.2 mg / d. After that, a load of 0.1 g / d is applied to the skein, and the skein is kept at a temperature of 20°C and a relative humidity of 65% for 24 hours. After that, the length L of the fiber sample is measured under a load of 0.1 g / d. ０ Next, the sample was immersed in water at 20° C. for 1 minute under no load, taken out, and a load of 0.1 g / d was applied to the sample, and the length L １ The water absorption elongation was calculated using the calculated length by formula (4). Water absorption elongation (%) = [(L １ -L ０ ) / L ０ ] × 100 ... (4)

[0113] L. Number of Defects on the Fiber Surface and Inside the Fiber The cylindrical knitted fabric prepared by the method described in Section F and subjected to hot water treatment was vapor-deposited with a platinum-palladium alloy and observed at 1000x magnification using a Hitachi S-4000 scanning electron microscope (SEM), and 10 random micrographs were taken. In the resulting 10 photographs, the fiber surfaces constituting the cylindrical knitted fabric were observed and the number of cracks was counted. In addition, five fibers were randomly extracted from the cylindrical knitted fabric after hot water treatment, and images were taken at a magnification that allowed all single fibers to be observed for each fiber sample. From each photographed image, the number of voids inside the fiber was counted for single fibers randomly extracted within the same image. The sum of the number of cracks on the fiber surface and the number of voids inside the fiber was taken as the number of defects, and a sample with 10 or fewer defects was deemed to pass.

[0114] M. α-type crystal orientation parameter The fiber sample was measured by laser Raman spectroscopy, and the －１ The ratio of the intensity ratio of the Raman bands derived from the α-crystals of polyamide observed near the center of the film to the intensity ratio of the Raman bands in parallel polarized light ((I1120) parallel) and perpendicular polarized light ((I1120) perpendicular) was used as a parameter for evaluating the degree of orientation. －１ The scattering intensity under each polarization condition (parallel / perpendicular) was normalized using the Raman band intensity near the fiber axis (i.e., near the center). α-crystal orientation parameter = (I1120 / I1440) parallel / (I1120 / I1440) perpendicular. The samples for orientation measurement were embedded in resin (bisphenol-based epoxy resin, cured for 24 hours) and then sectioned using a microtome. The section thickness was 2.0 μm. The section samples were cut at a slight angle from the fiber axis so that the cut surface was elliptical, and measurements were taken at a location where the thickness of the minor axis of the ellipse was constant. Measurements were performed in microscopic mode, with a laser spot diameter of 1 μm at the sample position. Orientation analysis was performed at the center of the core and sheath layers, and orientation measurements were performed under polarized conditions. The polarization direction was considered to be parallel (when the polarization direction was aligned with the fiber axis) and perpendicular (when the polarization direction was perpendicular), and the degree of orientation was evaluated from the ratio of the Raman band intensities obtained. Three measurements were performed at each measurement point. Detailed conditions are shown below.

[0115] Laser Raman spectroscopy Apparatus: T-64000 (Joobin Yvon / Atago Bussan) Conditions: Measurement mode: Raman microscope Objective lens: ×100 Beam diameter: 1 μm Light source: Ar+ laser / 514.5 nm Laser power: 50 mW Diffraction grating: Single 600 gr / mm Slit: 100 μm Detector: CCD / Jobin Yvon 1024 × 256.

[0116] N. Dyeing Unevenness A tubular knit fabric was produced using the method described in Section F. Next, the resulting tubular knit fabric was placed in an aqueous solution containing 1 g / L sodium carbonate and NIKKAISHA Chemical surfactant Sunmol BK-80. The aqueous solution was heated to 80°C and treated for 20 minutes, after which it was dried in a hot air dryer at 60°C for 60 minutes. Next, it was dry-heat set at 160°C for 2 minutes, and the tubular knit fabric after dry-heat setting was placed in a dye solution of 100 times the mass of the tubular knit, containing dyes and auxiliaries appropriate for the type of fiber constituting the tubular knit fabric. The dyeing temperature and dyeing time were set appropriate for the type of fiber, and the tubular knit fabric was used as a sample. The L value was measured three times per sample using a Minolta CM-3700d spectrophotometer with a D65 light source, a 10° viewing angle, and SCE (specular reflection excluded) optical conditions. The average value, rounded to two decimal places, was used as the L value of the sample. This operation was performed on 10 randomly selected samples, and the variation rate was calculated from the average value and standard deviation of the L values ​​of the 10 samples. If the variation rate of the L values ​​of these 10 samples was 5.0% or less, it was determined that there was no uneven dyeing.

[0117] O. Abrasion Resistance A cylindrical knitted fabric produced by the method described in Section F and subjected to hot water treatment was tested according to JIS L1096 (2010) Section 8.19, Method E (Martindale method), and the abrasion resistance was evaluated based on the endpoint of yarn breakage or appearance change. An endpoint of 2,500 times or more was considered to be pass.

[0118] P. Water absorption and quick-drying property (drying speed) A cylindrical knitted fabric produced by the method described in section F and subjected to hot water treatment was kept at a temperature of 20°C and a relative humidity of 65% for 24 hours, and then its mass was measured. ａ Next, 0.3 ml of water was dropped onto the center of the sample, and the mass was measured. ０分The moment when water was dropped onto the sample was set as 0 minutes, and the mass of the sample was measured at 5-minute intervals. ｎ分 Here, n minutes represents an arbitrary time at which the mass of the sample was measured, and represents 5 minutes, 10 minutes, 15 minutes, and other 5-minute intervals. The residual moisture rate WR at any arbitrary time was calculated using formula (5). WR = [(w ０分 -w ｎ分 ) / (w ０分 -w ａ )] × 100 (5) If the time during which the moisture residual rate WR calculated by the formula (5) fell below 30% was 75 minutes or less, the drying property was judged to be good, and if it was 60 minutes or less, the drying property was judged to be water-absorbing and quick-drying.

[0119] Q. Maintenance of moisture absorption before and after hot water treatment (change in ΔMR due to hot water treatment) The change in moisture absorption of the fiber before and after hot water treatment was evaluated as the difference in ΔMR, obtained by subtracting the ΔMR before hot water treatment calculated in section E from the ΔMR after hot water treatment calculated in section F. If the change in ΔMR was 2.0% or less, the moisture absorption of the fiber was considered to be maintained before and after hot water treatment.

[0120] R. Antistatic Property A cylindrical knitted fabric was produced by the method described in Section F and subjected to hot water treatment, and the time required for the electrostatic charge of the fabric to decrease to 50% of the initial electrostatic charge after voltage application was measured in an environment of a temperature of 20°C and a relative humidity of 40%, according to Method A (half-life measurement method) of JIS L1094 (Test methods for electrostatic charge of woven and knitted fabrics, 2014).

[0121] S. Wearing evaluation (heat sensation) The fiber samples obtained in the examples were measured by a known method to obtain a weight of 100 to 150 g / m ２A circular knitted fabric was produced by adjusting the temperature so that the temperature was 30°C. Next, the resulting knitted fabric was sewn into a shirt-like garment. Ten subjects were asked to wear the produced garment. Next, they were moved to a room with a temperature of 30°C and a relative humidity of 60%, simulating a summer indoor environment without air conditioning, and were asked to sit in a chair and rest. The condition inside the garment was assessed every 10 minutes for a total of six times until one hour had passed, with "no feeling of heat at all" being given a score of 5, "almost no feeling of heat" being given a score of 4, "slight feeling of heat" being given a score of 3, "feeling hot" being given a score of 2, and "feeling strong feeling of heat" being given a score of 1. The average score given by each of the 10 subjects at each response time was calculated. A score of 3.0 or higher was considered pass for all six scoring attempts, and a score of 4.0 or higher was considered excellent.

[0122] T. Single Fiber Fineness The number of single fibers contained in the fiber sample was counted in an image of the cross section of the fiber sample taken at 300x magnification using a Keyence VHX2000 digital microscope. Next, the fineness measured by the method described in Section C was divided by the number of single fibers, and the result was rounded to one decimal place to obtain the single fiber fineness.

[0123] U. Initial Tensile Strength In the tensile strength-elongation curve obtained when a fiber sample was measured by the method described in Section D, the initial tensile strength was determined by the method described in Section 8.10 of the Chemical Fiber Filament Yarn Test Method (JIS L1013 (2010)).

[0124] Example 1 Polymer A was polybutylene terephthalate (melt viscosity 60 Pa s, melting point 217°C) copolymerized with 50% by mass of polyethylene glycol (PEG6000S manufactured by Sanyo Chemical Industries, Ltd.) having a number average molecular weight of 8,300 g / mol at a spinning temperature of 270°C. Polybutylene terephthalate (melt viscosity 110 Pa s, melting point 222°C) was used as polymer A. After each polymer was melted separately, the polymers were weighed out so that the composite ratio of polymer A to polymer B was 30 / 70 by mass. The resulting mixture was then introduced into a spinning pack incorporating the composite spinneret shown in Figure 3. The incoming polymers were then discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric core-sheath cross section with an S / df of 0.06 and an S ratio of 35%. The discharged composite polymer stream was cooled and solidified in a cooling device, and a water-containing oil was added to the composite polymer stream using an oil supply device. The yarn was then taken up by the first take-up roller at a peripheral speed of 1000 m / min and a temperature of 90°C. The spinning draft (take-up roller speed / spinneret linear discharge speed) is shown in Table 1. The yarn taken up by the take-up roller was then taken up by the second draw roller at a surface temperature of 130°C, where it was drawn at a draw ratio of 2.02, expressed as the ratio of the peripheral speeds of the take-up roller and the draw roller. At the same time, the yarn was heat-treated by the draw roller. The heat-treated yarn was wound on a winder at a take-up speed of 2000 m / min to obtain a drawn yarn of 84 dtex-24 filaments. The drawn yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 14.1, and a coil pitch of 2.8 / mm. The evaluation results of the resulting crimped fiber are shown in Table 1.

[0125] Example 2: Polymer A and polymer B were weighed out to a conjugate ratio of 50 / 50 by mass, and the mixture was introduced into a spinning pack equipped with the conjugate spinneret shown in Figure 3. The incoming polymers were discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) so ​​as to form an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 45%. An 84 dtex-24 filament crimped fiber was obtained under the same conditions as in Example 1, except that the polymers were discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 45%. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 9.5, and a coil pitch of 1.7 / mm. The evaluation results of the resulting crimped fiber are shown in Table 1.

[0126] Example 3 At a spinning temperature of 285°C, a polybutylene terephthalate (melt viscosity 240 Pa s, melting point 222°C) with a different molecular weight from that of Example 1 was used as polymer B. Polymer A and polymer B were weighed out to a composite ratio of 50 / 50 by mass, and the resulting mixture was introduced into a spinning pack incorporating the composite spinneret shown in Figure 3. The incoming polymers were then discharged from a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric core-sheath cross section with an S / df of 0.06 and an S ratio of 42%. The discharged composite polymer stream was cooled and solidified in a cooling device and oiled with a water-containing oil agent using an oiling device. The first roll, a take-up roller, was then taken up at a peripheral speed of 1500 m / min and a temperature of 90°C. The yarn taken up by the take-up roller was then taken up by a second roll, a stretching roller, with a surface temperature of 150°C. The yarn was stretched at a draw ratio of 2.63, expressed as the ratio of the peripheral speeds of the take-up roller and the stretching roller, and simultaneously heat-treated by the stretching roller. The heat-treated yarn was wound on a winder with a winding speed of 3,890 m / min to obtain a drawn yarn of 56 dtex-24 filaments. The resulting drawn yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 8.0, and a coil pitch of 2.5 / mm. The evaluation results of the resulting crimped fiber are shown in Table 1.

[0127] 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. A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 3, except that the peripheral speed of the first take-up roller was set to 2000 m / min and the draw ratio was set to 1.96 times. The obtained drawn yarn was subjected to a boiling water treatment to induce crimping. The obtained crimped fiber had a coiled crimp morphology in the fiber axis direction, and it was confirmed that the Dc / df was 18.7 and the coil pitch was 2.2 / mm. The evaluation results of the obtained crimped fiber are shown in Table 1.

[0128] Example 5: Polymer A and polymer B were weighed to a conjugation ratio of 60 / 40 by mass and introduced into a spinning pack equipped with the conjugated spinneret shown in Figure 3. The incoming polymers were then discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 46%. A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 3, except that the draw ratio was 2.50 and the winding speed of the winder was 3700 m / min in the post-discharge process. The obtained drawn yarn was subjected to a boiling water treatment to induce crimping. The obtained crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 7.3, and a coil pitch of 2.8 / mm. The evaluation results of the obtained crimped fiber are shown in Table 1.

[0129] Example 6: Polymer A and polymer B were weighed to a conjugation ratio of 30 / 70 by mass and introduced into a spinning pack equipped with the conjugated spinneret shown in Figure 3. The incoming polymers were then discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 33%. A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 3, except that the draw ratio was 2.80 and the winding speed of the winder was 4100 m / min in the post-discharge process. The obtained drawn yarn was subjected to a boiling water treatment to induce crimping. The obtained crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 9.6, and a coil pitch of 2.6 / mm. The evaluation results of the obtained crimped fiber are shown in Table 1.

[0130] Example 7 A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 3, except that the distributor plate 10 of the composite spinneret shown in Figure 3 was changed to an eccentric sheath-core cross section with an S / df of 0.09 and an S ratio of 40%. The drawn yarn was subjected to a boiling water treatment to induce crimping. The obtained crimped fiber had a coiled crimp 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 crimped fiber are shown in Table 2.

[0131] Example 8 A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 5, except that polymer A was polyethylene terephthalate (melt viscosity 68 Pa s, melting point 251°C) copolymerized with 16% by mass of polyethylene glycol (PEG6000S manufactured by Sanyo Chemical Industries, Ltd.) having a number average molecular weight of 8,300 g / mol. The melt viscosity was 68 Pa s, and the melting point was 251°C. The drawn yarn was subjected to a boiling water treatment to induce crimping. The crimped fiber obtained had a coiled crimp morphology in the fiber axis direction, and it was confirmed that the Dc / df was 7.5 and the coil pitch was 3.3 / mm. The evaluation results of the crimped fiber obtained are shown in Table 2.

[0132] Example 9 Polymer A was polybutylene terephthalate (melt viscosity 240 Pa s, melting point 222°C), and polymer B was polyethylene terephthalate (melt viscosity 68 Pa s, melting point 251°C) copolymerized with 16% by mass of polyethylene glycol (PEG6000S manufactured by Sanyo Chemical Industries, Ltd.) having a number average molecular weight of 8,300 g / mol. Polymer A and polymer B were weighed out to a conjugation ratio of 30 / 70 by mass, and the mixture was introduced into a spinning pack incorporating the composite spinneret shown in Figure 3. Subsequently, a 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 5, except that the incoming polymers were discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) so ​​as to have an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 35%. The obtained drawn yarn was subjected to a boiling water treatment to induce crimping. The crimped fibers obtained had a coil-like crimped morphology in the fiber axis direction, a Dc / df of 2.8, and a coil pitch of 8.2 / mm. The evaluation results of the crimped fibers obtained are shown in Table 2.

[0133] Example 10 A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 3, except that the number of outlet holes in the composite spinneret incorporated in the spin pack was 36, the draw ratio was 2.38, and the winding speed of the winder was 3,480 m / min. The drawn yarn was subjected to a boiling water treatment to induce crimping. The obtained crimped fiber had a coil-like crimp morphology in the fiber axis direction, and it was confirmed that the Dc / df was 6.6 and the coil pitch was 2.7 / mm. The evaluation results of the obtained crimped fiber are shown in Table 2.

[0134] Example 11 A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 3, except that polymer A was a polyetheresteramide (melt viscosity 70 Pa s, melting point 200°C) containing 44% by mass of polycapramide, 6% by mass of terephthalic acid, and 50% by mass of polyethylene glycol with a number average molecular weight of 1,450 g / mol. The drawn yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, and was confirmed to have a Dc / df of 6.8 and a coil pitch of 2.9 / mm. The evaluation results of the resulting crimped fiber are shown in Table 2.

[0135] Example 12 At a spinning temperature of 270°C, polymer A was a polyetheresteramide (melt viscosity 85 Pa s, melting point 200°C) containing 44% by mass of polycapramide, 6% by mass of terephthalic acid, and 50% by mass of polyethylene glycol having a number average molecular weight of 1,450 g / mol (melt viscosity 85 Pa s, melting point 200°C), and polycapramide (melt viscosity 40 Pa s, melting point 220°C) was used as polymer B. After each polymer was melted separately, they were weighed out so that the composite ratio of polymer A to polymer B was 30 / 70 by mass, and then introduced into a spinning pack equipped with the composite spinneret shown in Figure 3. Subsequently, the incoming polymer was discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) so ​​as to form an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 33%. The discharged composite polymer stream was cooled and solidified in a cooling device, and then oiled with a water-free oil using an oiling device. The first take-up roller was then taken up at a peripheral speed of 1,300 m / min. The yarn taken up by the take-up roller was then taken up by a second draw roller (a stretching roller) with a surface temperature of 110°C. The yarn was then drawn at a draw ratio of 2.54, expressed as the ratio of the peripheral speeds of the take-up roller and the stretching roller, and simultaneously heat-treated by the draw roller. The heat-treated yarn was wound on a winder with a take-up speed of 3,300 m / min to obtain a drawn yarn with a 56 dtex-24 filament. The drawn yarn was then subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology along the fiber axis, a Dc / df of 5.9, and a coil pitch of 6.6 / mm. The evaluation results of the resulting crimped fiber are shown in Table 3.

[0136] Example 13: Polymer A and polymer B were weighed to a conjugate ratio of 50 / 50 by mass and introduced into a spinning pack equipped with the conjugate spinneret shown in Figure 3. The inflowing polymers were discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 43%. A 56 dtex-24 filament crimped fiber was obtained under the same conditions as in Example 12, except that in the post-discharge process, the peripheral speed of the take-up roller was 1500 m / min and the draw ratio was 2.20. The obtained crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 6.0, and a coil pitch of 4.6 / mm. The evaluation results of the obtained crimped fiber are shown in Table 3.

[0137] Example 14: Polycapramide (melt viscosity 160 Pa s, melting point 220°C) was used as polymer B. Polymer A and polymer B were weighed out at a conjugation ratio of 50:50 by mass and introduced into a spinning pack equipped with the conjugated spinneret shown in Figure 3. A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 13, except that the incoming polymer was discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 45%. The drawn yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 6.8, and a coil pitch of 4.9 / mm. The evaluation results of the resulting crimped fiber are shown in Table 3.

[0138] Example 15: A 56 dtex-24 filament crimped fiber was obtained under the same conditions as in Example 13, except that polyhexamethylene sebacamide (melt viscosity 100 Pa s, melting point 220°C) was used as polymer B. The obtained crimped fiber had a coiled crimp morphology 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 fiber are shown in Table 3.

[0139] Example 16: Polymer A and polymer B were weighed to a conjugation ratio of 60 / 40 by mass and introduced into a spinning pack equipped with the conjugate spinneret shown in Figure 3. The incoming polymers were then discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 46%. A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 12, except that in the post-discharge process, the peripheral speed of the take-up roller was set to 1600 m / min and the draw ratio was set to 2.06. The obtained drawn yarn was subjected to a boiling water treatment to induce crimping. The obtained crimped fiber had a coiled crimp morphology 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 crimped fiber are shown in Table 3.

[0140] Example 17 A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 13, except that the distributor plate of the composite spinneret shown in Figure 3 was changed to give an eccentric sheath-core cross section with an S / df of 0.09 and an S ratio of 40%. The drawn yarn was subjected to a boiling water treatment to induce crimping. The obtained crimped fiber had a coil-like crimp morphology in the fiber axis direction, a Dc / df of 5.1, and a coil pitch of 4.8 / mm. The evaluation results of the obtained crimped fiber are shown in Table 3.

[0141] Example 18 A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 13, except that the spinning temperature was 260°C and polymer A was a polyetheresteramide (melt viscosity 55 Pa s, melting point 200°C) containing 35% by weight of polycapramide, 6% by weight of adipic acid, and 59% by weight of polyethylene glycol with a number average molecular weight of 1,450 g / mol. The drawn yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 6.4, and a coil pitch of 5.0 / mm. The evaluation results of the resulting crimped fiber are shown in Table 4.

[0142] Example 19 Polycapramide (melt viscosity 160 Pa s, melting point 220°C) was designated Polymer A. Next, a polycapramide master chip was prepared by adding 20% ​​by mass of polyvinylpyrrolidone ("Ruviscol" K30SP, manufactured by BASF, K value = 30) to additive-free polycapramide. Subsequently, the master chip was chip-blended with additive-free polycapramide to prepare a polycapramide blend polymer with a polyvinylpyrrolidone addition rate of 5.0% by mass. This blend polymer (melt viscosity 130 Pa s, melting point 220°C) was designated Polymer B. Next, polymer A and polymer B were weighed out to a conjugation ratio of 50 / 50 by mass, and the mixture was introduced into a spinning pack incorporating the conjugated spinneret shown in Figure 3. The incoming polymers were discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric sheath-core cross section with an S / df of 0.06 and an S ratio of 46%, resulting in a 56 dtex-24 filament drawn yarn under the same conditions as in Example 12. The drawn yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 6.2, and a coil pitch of 9.1 / mm. The evaluation results of the resulting crimped fiber are shown in Table 4.

[0143] Example 20 A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 13, except that the number of outlet holes in the composite spinneret incorporated in the spin pack was 36, the peripheral speed of the take-up roller was 1600 m / min, and the draw ratio was 2.06. The drawn yarn was subjected to a boiling water treatment to induce crimping. The obtained crimped fiber had a coil-like crimp morphology in the fiber axis direction, and it was confirmed that the Dc / df was 5.1 and the coil pitch was 6.0 / mm. The evaluation results of the obtained crimped fiber are shown in Table 4.

[0144] (Comparative Example 1) A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 3, except that the distributor plate of the composite spinneret shown in Figure 3 was changed to have a concentric core-sheath cross section. The obtained drawn yarn was subjected to a boiling water treatment, but no crimping occurred. The evaluation results of the obtained fiber are shown in Table 5.

[0145] (Comparative Example 2) A drawn yarn of 56 dtex-24 filaments was obtained under the same conditions as in Example 3, except that polybutylene terephthalate (melt viscosity 50 Pa s, melting point 222°C) was used as polymer B. The obtained drawn yarn was subjected to a boiling water treatment, but no crimping occurred. The evaluation results of the obtained fiber are shown in Table 5.

[0146] (Comparative Example 3) A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 3, except that the distributor plate of the composite spinneret shown in Figure 3 was changed to a side-by-side cross-sectional form with a simple bonded structure. The obtained drawn yarn was subjected to a boiling water treatment, but the crimping that occurred was weak. In addition, since the hygroscopic polymer was exposed to the surface, it was eluted during the hot water treatment, reducing the hygroscopicity of the fiber. The evaluation results of the obtained fiber are shown in Table 5.

[0147] Comparative Example 4: Polymer A and polymer B were weighed to a composite ratio of 10 / 90 by mass and introduced into a spinning pack equipped with the composite spinneret shown in Figure 3. The incoming polymers were then extruded through an extrusion hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric sheath-core cross section with an S / df of 0.11 and an S ratio of 30%. A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 3, except that the draw ratio was 2.85 times and the winding speed of the winder was 4150 m / min in the post-extrusion process. The obtained drawn yarn was subjected to a boiling water treatment, but the crimping was weak and the stretchability was poor. Furthermore, the crimping elongation upon moisture absorption and / or water absorption was small, resulting in discomfort during perspiration. The evaluation results of the obtained fiber are shown in Table 5.

[0148] Comparative Example 5 At a spinning temperature of 270°C, polybutylene terephthalate (melt viscosity 110 Pa s, melting point 222°C) was used as polymer A, and polycapramide (melt viscosity 160 Pa s, melting point 220°C) was used as polymer B. The polymers A and B were weighed out to a composite ratio of 50 / 50 by mass, and the distributor plate of the composite spinneret shown in Figure 3 was modified, and the inflowing polymers were discharged from discharge holes (hole diameter 0.23 mm, number of holes 24) so ​​as to form a side-by-side cross-sectional form having a simply laminated structure. The discharged composite polymer stream was cooled and solidified in a cooling device, and then oiled with a water-free oil agent using an oiling device. The composite polymer stream was then taken up at a peripheral speed of 1300 m / min and a temperature of 90°C using a take-up roller (first roll). The yarn taken up by the take-up roller was then taken up by a second stretching roller with a surface temperature of 130°C. The stretched yarn was drawn at a draw ratio of 2.54, which is the ratio of the peripheral speeds of the take-up roller and the stretching roller, and simultaneously heat-treated by the stretching roller. The heat-treated yarn was wound on a winder with a winding speed of 3,300 m / min, yielding a drawn yarn of 56 dtex-24 filaments. The resulting drawn yarn was subjected to a boiling water treatment, but the crimping was weak and the stretchability was poor. Furthermore, the crimping elongation upon moisture absorption and / or water absorption was minimal, resulting in discomfort when sweating, etc. Furthermore, friction caused peeling at the interface between polymer A and polymer B in the fiber cross section, resulting in partial white streaks and reduced fabric quality, such as fuzzing. The evaluation results of the resulting fibers are shown in Table 5.

[0149] (Comparative Example 6) A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 13, except that the distributor plate of the composite spinneret shown in Figure 3 was changed to have a concentric core-sheath cross section. The obtained drawn yarn was subjected to a boiling water treatment, but no crimping occurred. The evaluation results of the obtained fiber are shown in Table 6.

[0150] Comparative Example 7 Polymer A was a polyetheresteramide (melt viscosity 50 Pa s, melting point 200°C) containing 35% by mass of polycapramide, 6% by mass of adipic acid, and 59% by mass of polyethylene glycol having a number average molecular weight of 1,450 g / mol (melt viscosity 50 Pa s, melting point 220°C), and polymer B was polycapramide (melt viscosity 50 Pa s, melting point 220°C). A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 12, except that the composite ratio of polymer A and polymer B was 50 / 50 by mass, and the inflow polymer was discharged from a discharge hole (hole diameter 0.23 mm, number of holes 24) so ​​as to have an eccentric sheath-core cross-sectional shape with an S / df of 0.06 and an S ratio of 48%. The obtained drawn yarn was subjected to a boiling water treatment, but no crimping occurred. The evaluation results of the obtained fiber are shown in Table 6.

[0151] (Comparative Example 8) A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 13, except that the distributor plate of the composite spinneret shown in Figure 3 was changed to form a side-by-side cross-sectional form with a simple bonded structure. The obtained drawn yarn was subjected to a boiling water treatment, but the crimping that occurred was weak. In addition, since the hygroscopic polymer was exposed to the surface, it was eluted during the hot water treatment, reducing the hygroscopicity of the fiber. The evaluation results of the obtained fiber are shown in Table 6.

[0152] Comparative Example 9: Polymer A and polymer B were weighed to a conjugation ratio of 10 / 90 by mass and introduced into a spinning pack equipped with the conjugate spinneret shown in Figure 3. Subsequently, the incoming polymers were discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric sheath-core cross section with an S / df of 0.10 and an S ratio of 28%. A 56 dtex-24 filament drawn yarn was obtained under the same conditions as in Example 13, except that in the post-discharge process, the peripheral speed of the take-up roller was 1200 m / min and the draw ratio was 2.75 times. The obtained drawn yarn was subjected to a boiling water treatment, but the developed crimp was weak and the stretchability was poor. Furthermore, the crimp elongation upon moisture absorption and / or water absorption was small, causing discomfort when sweating, etc. Furthermore, defects occurred within the fiber upon moisture absorption and / or water absorption, resulting in a deterioration in fabric quality. The evaluation results of the obtained fibers are shown in Table 6.

[0153] Example 21: Polymer A was polybutylene terephthalate (melt viscosity 50 Pa s, melting point 217°C) copolymerized with 50% by mass of polyethylene glycol (PEG6000S manufactured by Sanyo Chemical Industries, Ltd.) having a number average molecular weight of 8,300 g / mol at a spinning temperature of 285°C. Polybutylene terephthalate (melt viscosity 240 Pa s, melting point 222°C) was used as polymer A. After each polymer was melted separately, the polymers were weighed out so that the composite ratio of polymer A to polymer B was 50 / 50 by mass, and then introduced into a spinning pack incorporating the composite spinneret shown in Figure 3. The incoming polymers were then discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric core-sheath cross section with an S / df of 0.06 and an S ratio of 42%. The discharged composite polymer stream was cooled and solidified in a cooling device, and a water-free oil was added using an oil supply device. The yarn was then taken up at a peripheral speed of 2500 m / min on the take-up roller, which was the first roll. Subsequently, the yarn taken up on the take-up roller was taken up on a stretching roller, which was the second roll, at a peripheral speed of 2500 m / min and a surface temperature of 25°C. The yarn taken up on the stretching roller was wound on a winder with a winding speed of 2500 m / min, to obtain an unstretched yarn of 84 dtex-24 filaments. The unstretched yarn obtained was processed using a friction-type false twisting machine at a processing ratio of 1.50, a processing speed of 250 m / min, a false twist number of 3000 T / m, and a heater temperature of 170°C, to obtain a false twist textured yarn of 56 dtex-24 filaments. The resulting false twist textured yarn was subjected to a boiling water treatment to develop crimps. The crimped fibers obtained had a coil-like crimped morphology in the fiber axis direction, a Dc / df of 7.5, and a coil pitch of 4.5 / mm. The evaluation results of the crimped fibers obtained are shown in Table 7.

[0154] Example 22: An 84 dtex-24 filament undrawn yarn was obtained under the same conditions as in Example 21. The obtained undrawn yarn was processed using a friction-type false twisting machine at a processing ratio of 1.50, a processing speed of 250 m / min, a false twist number of 700 T / m, and a heater temperature of 170°C to obtain a 56 dtex-24 filament false twist textured yarn. The resulting false twist textured yarn was subjected to a boiling water treatment to induce crimping. The obtained crimped fiber had a coiled crimp morphology in the fiber axis direction, and was confirmed to have a Dc / df of 7.6 and a coil pitch of 4.1 / mm. The evaluation results of the obtained crimped fiber are shown in Table 7.

[0155] Example 23: A 70 dtex-24 filament undrawn yarn was obtained under the same conditions as in Example 21, except that the peripheral speed of the first take-up roller was 3500 m / min, the peripheral speed of the second stretching roller was 3500 m / min, and the winder take-up speed was 3500 m / min. The resulting undrawn yarn was processed using a friction-type false twisting machine at a processing ratio of 1.25, a processing speed of 250 m / min, a false twist number of 3000 T / m, and a heater temperature of 170°C to obtain a 56 dtex-24 filament false twist textured yarn. The resulting false twist textured yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 8.2, and a coil pitch of 3.8 / mm. Evaluation results for the resulting crimped fiber are shown in Table 7.

[0156] Comparative Example 10: An 84 dtex-24 filament undrawn yarn was obtained under the same conditions as in Example 21. The resulting undrawn yarn was processed using a friction-type false twisting machine at a processing ratio of 1.50, a processing speed of 250 m / min, a false twist number of 10,000 T / m, and a heater temperature of 170°C to obtain a 56 dtex-24 filament false twist textured yarn. The resulting false twist textured yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, but the Dc / df was small and the coil pitch number was excessive. Furthermore, the crimp elongation upon moisture absorption and / or water absorption was small, causing discomfort during sweating, etc. Furthermore, significant deformation of the fiber cross section during processing, defects on the fiber surface due to hot water treatment, and elution of the hygroscopic polymer, resulting in reduced moisture absorption. The evaluation results of the resulting fiber are shown in Table 7.

[0157] Example 24 At a spinning temperature of 270°C, polymer A was a polyetheresteramide (melt viscosity 85 Pa s, melting point 200°C) containing 44% by mass of polycapramide, 6% by mass of terephthalic acid, and 50% by mass of polyethylene glycol having a number-average molecular weight of 1,450 g / mol (melt viscosity 85 Pa s, melting point 200°C), and polymer B was polycapramide (melt viscosity 160 Pa s, melting point 220°C). After each polymer was melted separately, the polymers were weighed out so that the composite ratio of polymer A to polymer B was 50 / 50 by mass, and the resulting mixture was introduced into a spinning pack incorporating the composite spinneret shown in Figure 3. The incoming polymers were then discharged through a discharge hole (hole diameter 0.23 mm, number of holes 24) to form an eccentric core-sheath cross-sectional shape with an S / df of 0.06 and an S ratio of 45%. The discharged composite polymer stream was cooled and solidified in a cooling device, and a water-free oil was added using an oiling device. The yarn was then taken up at a peripheral speed of 3,500 m / min on the take-up roller, which was the first roll. Subsequently, the yarn taken up on the take-up roller was taken up on a stretching roller, which was the second roll, at a peripheral speed of 3,500 m / min and a surface temperature of 25°C. The yarn taken up on the stretching roller was wound on a winder with a winding speed of 3,500 m / min, to obtain an unstretched yarn of 67 dtex-24 filaments. The unstretched yarn obtained was processed using a friction-type false twisting machine at a processing ratio of 1.20, a processing speed of 400 m / min, a false twist number of 4,000 T / m, and a heater temperature of 150°C, to obtain a false twist textured yarn of 56 dtex-24 filaments. The resulting false twist textured yarn was subjected to a boiling water treatment to develop crimps. The crimped fibers obtained had a coil-like crimped morphology in the fiber axis direction, a Dc / df of 5.3, and a coil pitch of 8.4 / mm. The evaluation results of the crimped fibers obtained are shown in Table 8.

[0158] Example 25: An undrawn yarn of 67 dtex-24 filaments was obtained under the same conditions as in Example 24. The undrawn yarn was processed using a friction-type false twisting machine at a processing ratio of 1.20, a processing speed of 400 m / min, a false twist number of 680 T / m, and a heater temperature of 150°C to obtain a false twisted yarn of 56 dtex-24 filaments. The false twisted yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, and was confirmed to have a Dc / df of 5.7 and a coil pitch of 8.2 / mm. The evaluation results of the resulting crimped fiber are shown in Table 8.

[0159] Example 26: A 64 dtex-24 filament undrawn yarn was obtained under the same conditions as in Example 24, except that the peripheral speed of the first take-up roller was 4000 m / min, the peripheral speed of the second stretching roller was 4000 m / min, and the winder take-up speed was 4000 m / min. The undrawn yarn was processed using a friction-type false twisting machine at a processing ratio of 1.15, a processing speed of 400 m / min, a false twist number of 3500 T / m, and a heater temperature of 150°C to obtain a 56 dtex-24 filament false twist textured yarn. The resulting false twist textured yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, a Dc / df of 6.1, and a coil pitch of 8.1 / mm. Evaluation results for the resulting crimped fiber are shown in Table 8.

[0160] Comparative Example 11: An undrawn yarn of 67 dtex-24 filaments was obtained under the same conditions as in Example 24. The undrawn yarn was processed using a friction-type false twisting machine at a processing ratio of 1.20, a processing speed of 400 m / min, a false twist number of 8000 T / m, and a heater temperature of 150°C to obtain a false twisted yarn of 56 dtex-24 filaments. The resulting false twisted yarn was subjected to a boiling water treatment to induce crimping. The resulting crimped fiber had a coiled crimp morphology in the fiber axis direction, but the Dc / df was small and the coil pitch number was excessive. Furthermore, the crimp elongation upon moisture absorption and / or water absorption was small, causing discomfort upon sweating, etc. Furthermore, defects occurred within the fiber upon moisture absorption and / or water absorption, resulting in a deterioration in fabric quality. The evaluation results of the resulting fiber are shown in Table 8.

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[0165]

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[0167]

[0168]

[0169] The crimped fiber of this embodiment can suppress defects on the fiber surface or inside the fiber by dispersing the stress generated by volumetric swelling of the fiber upon moisture absorption through the elongation of the crimp imparted to the composite fiber. Furthermore, when made into a woven or knitted fabric, the crimp elongates upon moisture absorption and / or water absorption, suppressing a decrease in breathability of the fabric and preventing a loss of comfort even when sweating. Furthermore, the fiber retains excellent moisture absorption even with repeated use, and also has the stretch performance necessary for movement tracking, making it particularly suitable for use in clothing applications where comfort is required.

[0170] Although the embodiments of the present invention have been described above, the embodiments are not limited by the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments. This application is based on a Japanese patent application (Patent Application No. 2022-020215) filed on February 14, 2022, the contents of which are incorporated herein by reference.

[0171] a Position of the center of gravity of polymer A in the fiber cross section c Center of the fiber cross section E Any point on the interface between polymer A and polymer B F Intersection of the fiber surface with a perpendicular line to the tangent to the interface between polymer A and polymer B M1, M2 Any adjacent peaks in the crimped form of a single fiber constituting the crimped fiber V Peak of a valley in the crimped form of a single fiber constituting the crimped fiber 1 Shortest distance between point V and the line connecting M1 and M2 2 Distance between any adjacent peaks M1, M2 in the coiled crimped form 3 Fiber axial direction in the crimped form of a single fiber constituting the crimped fiber 4 Polymer A 5 Polymer B 6 Tangent to the interface between polymer A and polymer B 7 Minimum thickness of polymer B covering polymer A 8 Single fiber diameter 9 Metering plate 10 Distribution plate 11 Discharge plate

Claims

1. A crimped fiber is a conjugate fiber made of two polymers, polymer A and polymer B, which has a coiled crimped morphology in the fiber axis direction, the ratio Dc / df of the coil diameter Dc to the single fiber diameter df being 2.0 to 20.0, the number of coil pitches being 1.0 / mm to 10.0 / mm, polymer A being completely covered with polymer B in the fiber cross section, and the moisture absorption / desorption parameter ΔMR being 2.0% or more.

2. 2. The crimped fiber according to claim 1, wherein the polymer having the higher moisture absorption of the two polymers is polymer A.

3. 2. The crimped fiber according to claim 1, wherein the two types of polymers have the same type of bond in the main skeleton constituting the repeating units of the two types of polymers.

4. A crimped fiber as described in claim 1, characterized in that the composite form in the fiber cross section is an eccentric core-sheath cross section that satisfies the following requirements (1) and (2). (1) The ratio S / df of the minimum thickness S of the polymer B to the single fiber diameter df is 0.01 or more and 0.10 or less. (2) The circumferential length of the part having a thickness within 1.05 times the minimum thickness S is 30% or more of the circumference of the fiber cross section.

5. The crimped fiber described in claim 1, characterized in that the polymer B is an aromatic polyester and has an initial tensile resistance of 10 cN / dtex or more and 100 cN / dtex or less.

6. The crimped fiber described in claim 1, characterized in that polymer B is an aliphatic polyamide, and the alpha crystal orientation parameter of polymer B, the aliphatic polyamide, is 1.7 or more and 2.6 or less.

7. A textile product using the crimped fiber according to any one of claims 1 to 6.