JP2020076172A - Hygroscopic extra fine composite fiber and fiber structure - Google Patents

Abstract

To provide a hygroscopic extra fine composite fiber in which high hygroscopicity and wear resistance are consistent, and also, feeling when being made into a fiber structure is satisfactory.SOLUTION: A hygroscopic extra fine composite fiber has the characteristics of the following (1) to (5) that: (1) a polymer having hygroscopicity is perfectly covered with a polyester polymer; (2) the polymer having hygroscopicity is a copolyester polymer; (3) a moisture absorptivity difference (▵MR) after hot water treatment is 2.0 to 10.0%; (4) single fiber fineness is 0.50 to 1.50 dtex; and (5) outermost layer thickness is 2.5 to 4.5 μm, where the outermost thickness denotes a difference between the radius of the fiber and the radius of a circumcircle obtained by connecting the points most distant from a fiber center in an island(core) component arranged at the outermost circumference, and being the thickness of a sea (sheath) component.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a hygroscopic ultrafine composite fiber having both high hygroscopicity and abrasion resistance and good texture.

  The ultrafine polyester fiber is inexpensive and excellent in mechanical properties and dry feeling, and when it is formed into a fiber structure, a soft texture can be obtained. Therefore, it is used in a wide range of applications including clothing. However, since it has poor hygroscopicity, it has problems to be solved from the viewpoint of wearing comfort, such as generation of a stuffy feeling when the humidity is high in the summer and generation of static electricity when the humidity is low in the winter.

  In order to improve the above-mentioned drawbacks, various proposals have been made so far regarding methods of imparting hygroscopicity to polyester fibers. As a general method for imparting hygroscopicity, copolymerization of a hydrophilic compound with polyester, addition of a hydrophilic compound and the like can be mentioned, and polyethylene glycol can be mentioned as an example of the hydrophilic compound.

  For example, Patent Document 1 proposes a polymer in which polyethylene glycol and polyester are blended in a core and a sea-island type composite fiber in which polyethylene terephthalate is disposed in a sheath. In this proposal, a hygroscopic polymer is arranged on the island to impart hygroscopicity to the polyester fiber.

  Patent Document 2 proposes a core-sheath type composite fiber having a single yarn fineness of 1.5 dtex or less in which a polyethylene glycol copolymerized polyester containing a non-reactive ionic component is arranged in the core and polyethylene terephthalate is arranged in the sheath. In this proposal, a hygroscopic polymer is arranged in the core to impart hygroscopicity to the polyester fiber, and the single yarn fineness is set to 1.5 dtex or less to soften the texture of the cloth.

  Patent Document 3 proposes a polyethylene glycol copolyester containing a cross-linking agent in the island and a sea-island type composite fiber in which polyethylene terephthalate is arranged in the sea. In this proposal, a hygroscopic polymer containing a cross-linking agent is arranged on the islands to impart hygroscopicity to the polyester fibers and suppress the change over time.

JP, 2004-277911, A JP, 2010-7191, A Japanese Patent Laid-Open No. 8-198954

  However, the method described in Patent Document 1 has a problem that polyethylene glycol, which is a core component responsible for hygroscopicity during hot water treatment such as dyeing, elutes into the treatment liquid, and hygroscopicity decreases after hot water treatment.

  In the method described in Patent Document 2, as the hygroscopic polymer of the core component swells in volume during hot water treatment such as dyeing, stress concentrates at the interface between the core component and the sheath component, resulting in cracking of the sheath component, There is a problem that the hygroscopic polymer as the core component is eluted from the cracked portion as a starting point and the hygroscopicity is lowered after the hot water treatment. Further, since the core ratio is increased in order to impart hygroscopicity, there is a problem that the outermost layer has a small thickness of the sheath component and is whitened by abrasion.

  The method described in Patent Document 3 has a problem that it is difficult to reduce the fineness because the hygroscopic polymer contains a cross-linking agent, and the texture of the fiber structure is hard.

  The object of the present invention is to solve the above-mentioned problems of the prior art, and is excellent in abrasion resistance as well as having high hygroscopicity even after hot water treatment such as dyeing, and further, the texture when formed into a fiber structure is good. Therefore, it is an object of the present invention to provide a hygroscopic ultrafine composite fiber that can be suitably used for clothing.

The above problems can be solved by a hygroscopic ultrafine composite fiber having the following characteristics (1) to (5).
(1) The polyester polymer completely covers the hygroscopic polymer. (2) The hygroscopic polymer is a copolyester polymer. (3) The moisture absorption difference (ΔMR) after hot water treatment is 2.0-10.0%
(4) Single fiber fineness of 0.50 to 1.50 dtex
(5) Outermost layer thickness is 2.5 to 4.5 μm
The outermost layer thickness is the difference between the radius of the fiber and the radius of the circumscribed circle connecting the points with the longest distance from the fiber center in the island (core) component arranged on the outermost periphery, and is present in the outermost layer. Indicates the thickness of the sea (sheath) component.

  The hygroscopic ultrafine composite fiber obtained in the present invention is excellent in high hygroscopicity and abrasion resistance even after hot water treatment such as dyeing, and moreover, since it has a good texture when formed into a fiber structure, It can be suitably used in clothing applications.

1 (a) to 1 (j) are views showing an example of the cross-sectional shape of the conjugate fiber of the present invention. FIG. 2 (a) is an example of a cross-sectional shape of a composite fiber in which a hygroscopic polymer having an air layer at the interface is not adhered to a polyester-based polymer, and FIG. 2 (b) shows a hygroscopic polymer as a fiber. It is a figure which shows an example of the cross-sectional shape of the conjugate fiber exposed on the surface, and is different from the embodiment of the present invention.

  The moisture absorption difference (ΔMR) in the present invention means the moisture absorption rate at a temperature of 30 ° C. and a humidity of 90% RH assuming the temperature and humidity inside clothes after light exercise, and the outside temperature humidity at a temperature of 20 ° C. and a humidity of 65% RH. It is the difference in moisture absorption rate, and represents the value measured by the method described in the Example section. In the present specification, having hygroscopicity means that the ΔMR is 2.0% or more, and the higher the value of ΔMR, the higher the hygroscopicity and the better the wearing comfort.

  The single fiber fineness in the present invention means the weight (g) per 10,000 m of the single fiber, and represents the value obtained by dividing the weight (total fineness) per 10,000 m of the multifilament by the number of filaments. The smaller the single fiber fineness, the smaller the fiber diameter of the single fiber and the larger the specific surface area, and the softer the texture of the fiber structure.

  The outermost layer thickness in the present invention is the difference between the radius of the fiber and the radius of the circumscribed circle connecting the points with the longest distance from the fiber center in the island (core) component arranged at the outermost periphery, It represents the thickness of the existing sea (sheath) component.

The toughness in the present invention refers to the strength (cN / dtex) and the elongation (%) calculated according to JIS L1013: 2010 (Chemical fiber filament yarn test method) 8.5.1. The calculated value represents the value measured by the method described in the section of Examples. In the present specification, good toughness means that the toughness is 16.5 or more. The higher the toughness, the better the process passability, and the better the durability when formed into a fiber structure.
Toughness = strength × (elongation) ^1/2 (I).

  In the hygroscopic ultrafine composite fiber of the present invention, the hygroscopic polymer is completely covered with the polyester polymer. By completely covering the hygroscopic polymer with the polyester-based polymer, interfacial peeling due to external force is suppressed and wear resistance is improved. Examples of the composite form in which the polyester polymer completely covers the hygroscopic polymer include core-sheath type composite fibers and sea-island type composite fibers, but are not limited thereto. Among them, the sea-island type composite fiber suppresses the cracking of the sea component due to the volume swelling of the hygroscopic polymer at the time of absorbing moisture or absorbing water, so that the quality is lowered due to the occurrence of spots and fluff, and during hot water treatment such as dyeing. It is preferable because the hygroscopic polymer is suppressed from being deteriorated due to elution into hot water.

  The hygroscopic polymer of the hygroscopic ultrafine composite fiber of the present invention is a copolymerized polyester-based polymer composed of a copolymer of a hydrophilic polymer and a polyester, and has a moisture absorption difference (ΔMR) of 2.0% or more. Is. By forming a covalent bond by copolymerization, elution of the hygroscopic polymer into hot water during hot water treatment such as dyeing is suppressed, and high hygroscopicity is exhibited even after hot water treatment. Further, the copolymerization with polyester improves the mechanical properties.

  A preferred embodiment of the hygroscopic polymer having hygroscopic properties of the hygroscopic ultrafine composite fiber of the present invention will be described in detail in the description of the production method, and among them, copolymerized polybutylene terephthalate is preferred. If it is a copolymerized polybutylene terephthalate, mechanical properties are improved due to its high crystallinity, and since it is difficult for hot water to flow, elution of the hygroscopic polymer into hot water during hot water treatment such as dyeing is suppressed, High hygroscopicity is exhibited even after hot water treatment. Polybutylene terephthalate obtained by copolymerizing polyethylene glycol and / or its derivative is more preferable because the resulting hygroscopic ultrafine composite fiber has a good color tone.

  The moisture absorption difference (ΔMR) of the hygroscopic ultrafine composite fiber of the present invention after hot water treatment is 2.0 to 10.0%. When the difference in moisture absorption rate (ΔMR) after hot water treatment is 2.0% or more, the hygroscopicity is excellent and the stuffy feeling in clothes is suppressed. On the other hand, when the difference in moisture absorption rate (ΔMR) after hot water treatment is 10.0% or less, cracking of the sea (sheath) component due to volume swelling of the hygroscopic polymer is suppressed, and the quality can be maintained. From the viewpoint of hygroscopicity and quality, the difference in moisture absorption rate (ΔMR) after hot water treatment is preferably 3.0 to 8.0%.

  The outermost layer thickness of the hygroscopic ultrafine composite fiber of the present invention is 2.5 to 4.5 μm. When the thickness of the outermost layer is 2.5 μm or more, the abrasion resistance is good and the whitening due to abrasion is suppressed. On the other hand, when the thickness of the outermost layer is 4.5 μm or less, the volume swelling of the hygroscopic polymer is not impaired, the hygroscopicity is excellent, and the stuffy feeling in clothes is suppressed. From the viewpoint of wear resistance and hygroscopicity, the outermost layer thickness is preferably 3.0 to 4.0 μm.

  The composite ratio (weight ratio) of the sea (sheath) component // island (core) component of the hygroscopic ultrafine composite fiber of the present invention is preferably 70 // 30 to 97 // 3. If the composite ratio of the sea (sheath) component is 70% by weight or more, the outermost layer thickness of 2.5 μm or more can be secured, and the firmness, elasticity and dry feel of the sea (sheath) component can be obtained. Therefore, it is preferable. On the other hand, when the composite ratio of the sea (sheath) component is 97% by weight or less, that is, when the composite ratio of the island (core) component is 3% by weight or more, the hygroscopicity is excellent and the stuffy feeling in the clothes is suppressed, which is preferable. ..

  The fineness (total fineness) of the hygroscopic ultrafine composite fiber of the present invention as a multifilament is not particularly limited and can be appropriately selected depending on the application and required characteristics, but is preferably 10 to 500 dtex. When the total fineness is 10 dtex or more, the yarn breakage is small, the process passability is good, and in addition, the occurrence of fluff is small and the durability is excellent, which is preferable. On the other hand, if the total fineness is 500 dtex or less, the flexibility of the fiber structure is not impaired, which is preferable.

  The single fiber fineness of the hygroscopic ultrafine composite fiber of the present invention is 0.50 to 1.50 dtex. When the single fiber fineness is 0.50 dtex or more, the mechanical properties become good and the quality can be maintained. On the other hand, when the single fiber fineness is 1.50 dtex or less, a soft texture can be obtained when the fiber structure is formed. From the viewpoint of mechanical properties and texture, the single fiber fineness is preferably 0.80 to 1.20 dtex.

  The strength of the hygroscopic ultrafine composite fiber of the present invention is not particularly limited and may be appropriately selected depending on the application and required characteristics, but is preferably 2.5 to 5.0 cN / dtex. When the strength of the composite fiber is 2.5 cN / dtex or more, less fluff is generated during use and the durability is excellent. On the other hand, when the strength of the composite fiber is 5.0 cN / dtex or less, a soft texture is obtained when the fiber structure is formed. From the viewpoint of durability and texture, it is more preferably 2.8 to 4.5 cN / dtex.

  The elongation of the hygroscopic ultrafine composite fiber of the present invention is not particularly limited and can be appropriately selected depending on the application and required characteristics, but is preferably 10 to 60% from the viewpoint of durability. When the elongation of the composite fiber is 10% or more, the abrasion resistance of the fiber and the fiber structure is good, less fluff is generated during use, and the durability is good, which is preferable. On the other hand, when the elongation of the composite fiber is 60% or less, the dimensional stability of the fiber and the fiber structure becomes good, which is preferable.

  The toughness of the hygroscopic ultrafine composite fiber of the present invention is preferably 16.5 or more. When the toughness is 16.5 or more, the process passability is good, and the durability after repeated wearing / washing after forming the fiber structure is excellent, which is preferable. From the viewpoint of process passability and durability, toughness is more preferably 18.0 or more.

  The hygroscopic ultrafine conjugate fiber of the present invention is not particularly limited with respect to the shape of the island (core) component in the fiber cross section, and may have a perfect circular cross section or a non-circular cross section. Specific examples of the non-circular cross section include, but are not limited to, a multilobal shape, a polygonal shape, a flat shape, and an elliptical shape.

  The hygroscopic ultrafine composite fiber of the present invention is not particularly limited with respect to the cross-sectional shape of the fiber, can be appropriately selected according to the application and required characteristics, may be a perfect circular circular cross section, a non-circular cross section. It may be. Specific examples of the non-circular cross section include, but are not limited to, a multilobal shape, a polygonal shape, a flat shape, and an elliptical shape.

  Next, a method for producing the hygroscopic ultrafine composite fiber of the present invention will be described.

  The hygroscopic ultrafine composite fiber of the present invention comprises a polymer having a hygroscopic property as an island (core) component and a polyester polymer as a sea (sheath) component, and a known melt spinning method, drawing method, crimping process such as false twisting. Can be obtained using the method.

  The sea (sheath) component used in the production of the hygroscopic ultrafine composite fiber of the present invention is a polyester polymer. Specific examples thereof include, but are not limited to, aromatic polyesters such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate, and aliphatic polyesters such as polylactic acid and polyglycolic acid. Among them, the aromatic polyester is preferable because it is excellent in mechanical properties and durability, polyethylene terephthalate is more preferable because it gives the firmness and elasticity of the polyester fiber, and the cationic dyeable polyethylene terephthalate shows a clear color forming property. It is particularly preferable because it can prevent dye contamination when mixed with polyurethane fibers. Cationic dyeable polyethylene terephthalate is polyethylene terephthalate obtained by copolymerizing a component capable of interacting with a cationic dye. Specific examples of the copolymerizable component capable of interacting with the cationic dye include 5-sulfoisophthalic acid metal salt, which includes, but is not limited to, lithium salt, sodium salt, potassium salt, rubidium salt, cesium salt and the like. .. Among them, lithium salt and sodium salt can be preferably used.

  The island (core) component used in the production of the hygroscopic ultrafine composite fiber of the present invention is a hygroscopic polymer made of a copolymer of polyester and a hydrophilic polymer. Specific examples thereof include polymers such as polyether ester and 5-sulfoisophthalic acid metal salt copolyester, but are not limited thereto. Among them, polyether ester is preferable because it has excellent hygroscopicity. Polyether copolymerized polyester is more preferable from the viewpoint of mechanical properties, polyether copolymerized polybutylene terephthalate is further preferable from the viewpoint of high crystallinity and resistance to hot water flow, and polyethylene glycol and / or from the viewpoint of heat resistance. Polybutylene terephthalate obtained by copolymerizing the derivative is particularly preferable.

  As a polymer having a hygroscopic property composed of a copolymer of polyester and a hydrophilic polymer, an aromatic dicarboxylic acid and / or its ester-forming derivative and an aliphatic diol can be used from the viewpoint of hygroscopicity, heat resistance and mechanical properties. Is preferred, and a polyether ester having polyethylene glycol and / or its derivative as a copolymerization component is preferred. Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 5-sodium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, 5- (tetraalkyl) phosphonium sulfoisophthalic acid, 4,4′-diphenyldicarboxylic acid. Acid, 2,6-naphthalenedicarboxylic acid and the like, but are not limited thereto. Specific examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, hexanediol, cyclohexanediol, diethylene glycol, hexamethylene glycol, neopentyl glycol, and the like. Not limited. Among them, ethylene glycol, propylene glycol, and 1,4-butanediol are preferable because they are easy to handle during production and use, and 1,4-butane is preferable in terms of high crystallinity and difficulty in flowing hot water. A diol can be preferably used.

  In a polyether ester having an aromatic dicarboxylic acid and / or its ester-forming derivative and an aliphatic diol as main constituents and polyethylene glycol and / or its derivative as a copolymerization component, polyethylene glycol and / or a copolymerization component The number average molecular weight of the derivative is preferably 2000 to 30,000 g / mol. When the number average molecular weight of polyethylene glycol and / or its derivative is 2000 g / mol or more, hygroscopicity is excellent, which is preferable. On the other hand, when the number average molecular weight of polyethylene glycol and / or its derivative is 30,000 g / mol or less, polycondensation reactivity is high, unreacted polyethylene glycol and / or its derivative can be reduced, and heat of dyeing or the like can be reduced. Elution of the hygroscopic polymer into hot water during water treatment is suppressed, and hygroscopicity can be maintained even after hot water treatment, which is preferable.

  The copolymerization rate of polyethylene glycol and / or its derivative, which is a copolymerization component, is preferably 35 to 65% by weight. When the copolymerization rate of polyethylene glycol and / or its derivative is 35% by weight or more, the hygroscopicity is high, and when it is used as an island (core) component, a composite fiber excellent in hygroscopicity can be obtained, which is preferable. On the other hand, when the copolymerization rate of polyethylene glycol and / or its derivative is 65% by weight or less, unreacted polyethylene glycol and its derivative can be reduced, and the hot water of the hygroscopic polymer can be reduced during hot water treatment such as dyeing. It is preferable because the elution into the water is suppressed and the hygroscopicity can be maintained even after the hot water treatment.

  Aromatic dicarboxylic acid and / or its ester-forming derivative and an aliphatic diol, which are preferably used as the island (core) component in the production of the hygroscopic ultrafine composite fiber of the present invention, are the main components, and polyethylene glycol and / or its derivative are The method for producing the polyether ester as the copolymerization component is usually one of the following processes. That is, (A) a process in which dimethyl terephthalate and an aliphatic diol are used as raw materials, a low polymer is obtained by a transesterification reaction, and then a high molecular weight polymer is obtained by a polycondensation reaction, and (B) terephthalic acid and an aliphatic diol are used as raw materials. And a low polymer is obtained by a direct esterification reaction, and then a high molecular weight polymer is obtained by a subsequent polycondensation reaction. The method of adding polyethylene glycol and / or its derivative is not particularly limited. From the viewpoint of increasing the polycondensation reactivity of the polyethylene glycol and / or its derivative with the polyester and decreasing the amount of unreacted polyethylene glycol / or its derivative, the time of addition of the polyethylene glycol and / or its derivative is the transesterification reaction, Alternatively, it is added after the esterification reaction and before the polycondensation reaction starts.

  The sea (sheath) component and / or the island (core) component used in the production of the hygroscopic ultrafine composite fiber of the present invention are variously modified by adding secondary additives within a range not impairing the effects of the present invention. May be performed. Specific examples of the secondary additives include antioxidants, compatibilizers, plasticizers, ultraviolet absorbers, infrared absorbers, optical brighteners, antibacterial agents, nucleating agents, heat stabilizers, antistatic agents, colorings. Examples include, but are not limited to, inhibitors, modifiers, matting agents, defoamers, preservatives, latexes, fillers, inks, colorants, dyes, pigments and fragrances. These secondary additives may be used alone or in combination of two or more.

  In the production of the hygroscopic ultrafine composite fiber of the present invention, it is preferable that the polymer (chip) of each component be dried to have a water content of 300 ppm or less before performing melt spinning. When the water content is 300 ppm or less, the decrease in molecular weight due to hydrolysis and foaming due to water during melt spinning are suppressed, and stable spinning can be performed, which is preferable.

  In the production of the hygroscopic ultrafine composite fiber of the present invention, the chips dried in advance are supplied to a melt spinning machine such as an extruder type or a pressure melter type, and each component is melted separately and weighed by a metering pump. Then, it is introduced into a heated spinning pack in a spinning block, the molten polymer is filtered in the spinning pack, merged with a composite spinneret, and then discharged to form a fiber yarn. As a specific example of the composite base, a publicly known core-sheath composite base, a sea-island composite base in which a pipe group disclosed in JP2007-100243A is arranged, and a sea-island composite base described in JP2011-174215A. However, the present invention is not limited to these.

  In the production of the hygroscopic ultrafine composite fiber of the present invention, the fiber yarn discharged from the composite spinneret is cooled and solidified by a cooling device, taken up by a first godet roller, and wound by a winder through a second godet roller. It is taken up and becomes a winding thread. In addition, in order to improve spinning operability, productivity, and mechanical properties of the fiber, a heating cylinder or a heat insulating cylinder having a length of 2 to 20 cm may be installed below the composite spinneret if necessary. Further, the fiber yarn may be lubricated using an oil supply device, and the fiber yarn may be entangled using an entanglement device.

  The spinning temperature of the melt spinning in the production of the hygroscopic ultrafine composite fiber of the present invention can be appropriately selected depending on the melting point and heat resistance of each component, but is preferably 240 to 320 ° C. If the spinning temperature is 240 ° C. or higher, the elongation viscosity of the fiber yarn discharged from the composite spinneret is sufficiently lowered, and the discharge is stable, and further, the spinning tension does not become excessively high and the yarn breakage is suppressed. It is preferable because it is possible. On the other hand, if the spinning temperature is 320 ° C. or lower, thermal decomposition during spinning can be suppressed, and deterioration of mechanical properties and coloring of the fiber can be suppressed, which is preferable.

  The spinning speed of melt spinning in the production of the hygroscopic ultrafine composite fiber of the present invention can be appropriately selected according to the polymer composition of each component, the spinning temperature, and the like. In the case of a two-step method in which melt spinning is once performed and wound, and then, drawing or false twisting is separately performed, the spinning speed is preferably 500 to 6000 m / min. When the spinning speed is 500 m / min or more, the running yarn is stable and the yarn breakage can be suppressed, which is preferable. On the other hand, when the spinning speed is 6000 m / min or less, the yarn tension does not break due to the suppression of the spinning tension. It is preferable because stable spinning can be performed. In the case of a one-step method in which spinning and drawing are simultaneously performed without once winding, the spinning speed is preferably 500 to 5000 m / min for the low speed roller and 2500 to 6000 m / min for the high speed roller. When the low speed roller and the high speed roller are within the above ranges, the traveling yarn is stable, yarn breakage can be suppressed, and stable spinning can be performed, which is preferable.

  In the production of the hygroscopic ultrafine composite fiber of the present invention, when the drawing is carried out by a one-step method or a two-step method, either one-step drawing method or multi-step drawing method of two or more steps may be used. The heating method in drawing is not particularly limited as long as it is a device that can directly or indirectly heat the running yarn. Specific examples of the heating method include, but are not limited to, a heating roller, a hot pin, a hot plate, a liquid bath such as hot water and hot water, a hot air, a gas bath such as steam, and a laser. These heating methods may be used alone or in combination. As the heating method, control of the heating temperature, uniform heating of the running yarn, contact with the heating roller, contact with the heat pin, contact with the hot plate, and immersion in the liquid bath are taken from the viewpoint of not complicating the device. It can be suitably adopted.

  In the production of the hygroscopic ultrafine composite fiber of the present invention, the drawing temperature in the case of carrying out drawing can be appropriately selected depending on the strength and elongation of the fiber after drawing, but it is preferably 50 to 150 ° C. preferable. When the drawing temperature is 50 ° C. or higher, the yarn supplied to the drawing is sufficiently preheated, the thermal deformation during drawing is uniform, the occurrence of fineness unevenness can be suppressed, and the number of dyeing unevenness and fluff is reduced, and the quality is improved. Is preferable, which is preferable. On the other hand, when the stretching temperature is 150 ° C. or lower, fusion of fibers with each other and thermal decomposition due to contact with the heating roller can be suppressed, and process passability and quality are good, which is preferable. Moreover, you may heat-set at 60-150 degreeC as needed.

  The draw ratio in the case of carrying out drawing can be appropriately selected according to the elongation of the fiber before drawing, the strength and the elongation of the fiber after drawing, etc., but is 1.02 to 7.0 times. Preferably. A draw ratio of 1.02 times or more is preferable because mechanical properties such as strength and elongation of the fiber can be improved by drawing. On the other hand, when the draw ratio is 7.0 times or less, yarn breakage during drawing is suppressed, and stable drawing can be performed, which is preferable.

  Further, the stretching speed in the case of stretching can be appropriately selected depending on whether the stretching method is a one-step method or a two-step method. In the case of the one-step method, the speed of the high-speed roller having the above spinning speed corresponds to the drawing speed. When the two-step method is used for stretching, the stretching speed is preferably 30 to 1000 m / min. When the drawing speed is 30 m / min or more, the running yarn is stable and yarn breakage can be suppressed, which is preferable. On the other hand, when the drawing speed is 1000 m / min or less, yarn breakage during drawing is suppressed and stable drawing can be performed, which is preferable.

  In the production of the hygroscopic ultrafine composite fiber of the present invention, when false twisting is performed, only one-stage heater is used, so-called Woolly process, both one-stage heater and two-stage heater are used, so-called buleria process. Can be appropriately selected. The heating method of the heater may be either a contact type or a non-contact type. Specific examples of the false twisting machine include, but are not limited to, a friction disk type, a belt nip type, and a pin type.

  In the production of the hygroscopic ultrafine composite fiber of the present invention, the heater temperature when performing false twisting is preferably 120 to 210 ° C. If the heater temperature is 120 ° C or higher, the yarn supplied to the false twisting process is sufficiently preheated, the thermal deformation due to the drawing is uniform, the unevenness of fineness can be suppressed, and the uneven dyeing and the fluff are reduced. It is preferable because the quality becomes good. On the other hand, if the heater temperature is 210 ° C. or lower, fusion of fibers with each other due to contact with the heating heater and thermal decomposition are suppressed, so that thread breakage and stains on the heating heater are small, and process passability and quality are low. It is preferable because it is good.

  The draw ratio in the case of performing false twisting can be appropriately selected depending on the elongation of the fiber before false twisting, the strength and the elongation of the fiber after false twisting, and the like. It is preferably about 2.5 times. A draw ratio of 1.01 times or more is preferable because mechanical properties such as strength and elongation of the fiber can be improved by drawing. On the other hand, when the draw ratio is 2.5 times or less, yarn breakage during false twisting is suppressed, and stable false twisting can be performed, which is preferable.

  Further, the processing speed when performing false twisting can be appropriately selected, but is preferably 200 to 1000 m / min. When the processing speed is 200 m / min or more, the traveling yarn is stable and yarn breakage can be suppressed, which is preferable. On the other hand, when the processing speed is 1000 m / min or less, yarn breakage during false twisting is suppressed, and stable false twisting can be performed, which is preferable.

  The form of the fiber employed in the production of the hygroscopic ultrafine composite fiber of the present invention is not particularly limited, and may be any form such as monofilament, multifilament and staple. In addition, it is possible to process twisted yarns like ordinary fibers, and weaving and knitting can be handled in the same manner as ordinary fibers.

  The form of the fibrous structure using the hygroscopic ultrafine composite fiber of the present invention is not particularly limited, and may be a woven fabric, a knitted fabric, a pile fabric, a non-woven fabric, a spun yarn, a stuffed cotton, or the like according to a known method. In the case of a woven or knitted fabric, any woven or knitted structure may be used, such as plain weave, twill weave, satin weave or their modified weaves, warp knitting, weft knitting, circular knitting, lace knitting or their modified knitting. It can be suitably adopted.

  The hygroscopic ultrafine composite fibers of the present invention may be combined with other fibers by interwoven or interwoven when forming a fibrous structure, or may be formed into a fibrous structure after being mixed with other fibers.

  The hygroscopic ultrafine composite fiber of the present invention may be dyed in any state of fiber or fiber structure. The dyeing method is not particularly limited, and a cheese dyeing machine, a jet dyeing machine, a drum dyeing machine, a beam dyeing machine, a jigger, a high pressure jigger and the like can be suitably adopted according to a known method. There is no particular limitation on the dye concentration and the dyeing temperature, and a known method can be preferably used. If necessary, scouring may be performed before the dyeing process, and reduction cleaning or soaping treatment may be performed after the dyeing process.

  Hereinafter, the present invention will be described in more detail with reference to examples. The characteristic values of Examples and Comparative Examples were obtained by the following methods.

A. Number average molecular weight of polyethylene glycol or its derivative 500 mg of polyethylene glycol or its derivative used was dissolved in 5 mL of 0.1 M sodium chloride aqueous solution, and the filtrate obtained by filtering with a 0.45 μm cellulose filter was used as a sample for GPC measurement. .. Using this sample, the number average molecular weight was calculated by a GPC device (Alliance 2690 manufactured by Waters) under the following conditions.
Detector: Waters 2410 differential refractive index detector, sensitivity 128x
Column: Tosoh TSKgel G3000PWXLI
Solvent: 0.1M Sodium chloride aqueous solution Injection volume: 200 μL
Column temperature: 40 ° C
Standard substance: polyethylene glycol (Mw 106-10100 manufactured by Amal Co., Ltd.).

B. Sea (sheath) // island (core) composite ratio (weight ratio)
The obtained fiber was embedded with an epoxy resin, frozen with a FC-4E cryosectioning system manufactured by Reichert, and cut with a Reichert-Nissei ultracut N (ultramicrotome) equipped with a diamond knife. After that, the cut surface, that is, the cross-section of the fiber was observed with a scanning electron microscope (SEM) S-4000 manufactured by Hitachi, at the highest magnification at which the whole image of the single fiber can be observed. In the obtained photograph, the area ratio of the core component and the sheath component to the fiber cross-sectional area was calculated, and from the density of the sea (sheath) component and the island (core) component used as the raw material of the composite fiber, the sea (sheath) / / Island (core) composite ratio (weight ratio) was calculated.

C. Total fineness, single fiber fineness In an environment of a temperature of 20 ° C. and a humidity of 65% RH, 100 m of the fibers obtained in Examples and Comparative Examples were skeined using an INTEC electric scale measuring machine. The weight of the obtained skein was measured, and the total fineness (dtex) was calculated using the following formula (II), and the single fiber fineness (dtex) was calculated using the following formula (III). The measurement was performed 5 times for each sample, and the average value was adopted.
Total fineness (dtex) = weight of fiber 100 m (g) × 100 (II).
Single fiber fineness (dtex) = total fineness (dtex) / number of filaments (III).

D. Strength, Elongation The obtained fiber was used as a sample and calculated according to JIS L1013: 2010 (Chemical fiber filament yarn test method) 8.5.1. A tensile test was conducted under the conditions of an initial sample length of 20 cm and a tensile speed of 20 cm / min using an Orientec Tensilon UTM-III-100 type under an environment of a temperature of 20 ° C. and a humidity of 65% RH. The stress (cN) at the point showing the maximum load is divided by the total fineness (dtex) to calculate the strength (cN / dtex), and the elongation (L1) at the point showing the maximum load and the initial sample length (L0) are used. The elongation (%) was calculated by the following formula (IV). The measurement was performed 10 times for each sample, and the average value was taken as the strength and the elongation. A strength of 2.5 (cN / dtex) or higher was judged to be good, and a strength of 2.8 (cN / dtex) or higher was judged to be better.
Elongation (%) = {(L1−L0) / L0} × 100 (IV).

E. Toughness Toughness was calculated by the following formula (V) using the strength (cN / dtex) and the elongation (%) calculated in the above D. A toughness of 16.5 or more was judged to be good, and a toughness of 18.0 or more was considered to be better.
Toughness = strength × (elongation) ^1/2 ... (V).

F. Outermost layer thickness The obtained fiber was embedded with an epoxy resin, frozen with a Reichert FC-4E cryosectioning system, and cut with a Reichert-Nissei ultracut N (ultramicrotome) equipped with a diamond knife. After that, the cut surface, that is, the cross-section of the fiber was observed, and a micrograph was taken at the highest magnification at which the whole image of the single fiber can be observed. In the obtained photograph, the radius of the single fiber was obtained as the radius of the fiber using image processing software (WINROOF manufactured by Mitani Shoji Co., Ltd.), and the point with the longest distance from the fiber center in the island (core) component arranged on the outer periphery The radius of a perfect circle (circumscribing circle) circumscribing so as to contact with was calculated. Randomly extract 10 monofilaments from the obtained photographs, calculate the radius of the fiber and the radius of the circumscribed circle in the same manner, calculate the difference between the radius of the fiber and the radius of the circumscribed circle for each monofilament, and calculate the average. The value was taken as the outermost layer thickness. Since the fiber cross section is not necessarily a perfect circle, when it is not a perfect circle, a circle equivalent radius was calculated from the cross sectional area of the fiber cross section and adopted as the radius of the fiber.

G. Moisture absorption difference after scouring and hot water treatment (△ MR)
Using the obtained fiber as a raw material, a circular knitting machine NCR-BL manufactured by Eiko Sangyo Co., Ltd. (3 inch and a half (8.9 cm) in the kettle diameter, 27 gauge) to make about 2 g of a cylinder knit, and then 2 g / L of sodium carbonate Was poured into an aqueous solution containing a surfactant Granup US-20 manufactured by Meisei Chemical Co., Ltd., scoured at 80 ° C. for 20 minutes, and then dried in a hot air dryer at 60 ° C. for 60 minutes to give a scoured tubular knit. Further, the tube knitted after scouring is subjected to hot water treatment under the conditions of a bath ratio of 1: 100, a treatment temperature of 130 ° C. and a treatment time of 60 minutes, and then dried in a hot air dryer at 60 ° C. for 60 minutes to obtain a tube after the hot water treatment. Knitted

The moisture absorption rate (%) was calculated according to the water content of JIS L1096: 2010 (Test method for woven and knitted fabrics) 8.10 using cylindrical knitting after scouring and hot water treatment as a sample. First, after drying the tube knitting with hot air at 60 ° C. for 30 minutes, the tube knitting is allowed to stand still for 24 hours in the ESPEC constant temperature and humidity machine LHU-123 whose temperature is adjusted to 20 ° C. and humidity 65% RH. After measuring the weight (W1) of the knitting, the tube knitting was allowed to stand for 24 hours in a thermo-hygrostat adjusted to a temperature of 30 ° C. and a humidity of 90% RH, and the weight (W2) of the tube knitting was measured. Then, the tube knit was dried with hot air at 105 ° C. for 2 hours, and the weight (W3) of the tube knit after drying was measured. Using the weights W1 and W3 of the cylinder knitting, the moisture absorption rate MR1 (%) is calculated according to the following formula (VI) when the product is allowed to stand for 24 hours in an atmosphere of absolute dryness at a temperature of 20 ° C. and a humidity of 65% RH. Using the weights W2 and W3 of the above, the moisture absorption rate MR2 (%) when left standing for 24 hours in a temperature of 30 ° C. and a humidity of 90% RH was calculated by the following formula (VII), and then the following formula (VII) The moisture absorption difference (ΔMR) was calculated according to VIII). The measurement was performed 5 times for each sample, and the average value was used as the moisture absorption rate difference (ΔMR). When ΔMR was 2.0% or more, it was judged to have hygroscopicity, and when 3.0% or more, it was considered better.
MR1 (%) = {(W1-W3) / W3} × 100 (VI)
MR2 (%) = {(W2-W3) / W3} × 100 (VII)
Moisture absorption difference (ΔMR) (%) = MR2-MR1 (VIII).

H. Cracking of sea (sheath) component The hot-water treated tubular knitting produced in G above was vapor-deposited with a platinum-palladium alloy, and observed at 1,000 times using a Hitachi scanning electron microscope (SEM) S-4000 type. Photographs of 10 fields of view were taken at random. In the 10 photographs obtained, the total of the locations where the sea component is cracked is defined as the crack (location) of the sea (sheath) component, and if the number is 9 or less, the cracking of the sea (sheath) component is suppressed. Judgment was made: if 5 or less, it was better, and if 3 or less, it was even better.

I. Level dyeing Using the obtained fiber as a raw material, a circular knitting machine NCR-BL manufactured by Eiko Sangyo Co., Ltd. (3 inch and a half (8.9 cm) in the kettle diameter, 27 gauge) to make about 10 g of tubular knitting, The solution was added to an aqueous solution having a concentration of 2 g / L and a surfactant, Granup US-20, manufactured by Meisei Chemical Industry Co., Ltd., at a concentration of 1 g / L so that the bath ratio was 1:40, and the mixture was scoured at 80 ° C. for 20 minutes and then at 60 ° C. It was dried in a hot air dryer for 60 minutes. After heat setting at 180 ° C. for 3 minutes, it was added to a dyeing solution in which the concentration of the basic dye Nichilon Black manufactured by Nippon Kayaku was 5.0 wt% and the pH was adjusted to 5.0 so that the bath ratio was 1:30. Staining was performed at 120 ° C for 30 minutes. The dyed sample was put into an aqueous solution having a concentration of 0.5 g / L of Laccol ISF, a soaping agent manufactured by Meisei Chemical Industry Co., Ltd., at a bath ratio of 1:30, soaped at 60 ° C for 20 minutes, and then dried with hot air at 60 ° C. It was dried in the machine for 60 minutes. Finally, it was heat set at 160 ° C. for 3 minutes.

  Regarding the obtained tubular knitting, by a majority vote of 5 inspectors who have 5 years or more of quality judgment experience, "very uniformly dyed and no spots are observed at all" is S, "almost uniformly "It is dyed and almost no stain spots are observed" A, "It is dyed uniformly and only a few stain spots are seen" B, "Not dyed uniformly and it is clearly spotted Is recognized "as C, and B, A, and S are accepted. If there were the same number of votes, we narrowed down the choices to two classes and decided again by majority vote.

J. Quality With regard to the tubular knitting after the hot water treatment produced in the above G, by the majority vote of 5 inspectors who have 5 years or more of quality judgment experience, "no fluff and extremely excellent quality" are given as S and "fluff "There is almost no, excellent quality" is A, "There is some fluff, but good quality" is B, "There are many fluff and it is extremely inferior" is C, and B, A, and S are passed. .. If there were the same number of votes, we narrowed down the choices to two classes and decided again by majority vote.

K. Discoloration and fading after abrasion As a sample, the dyed tubular knitting prepared in the above I was sampled to have diameters of 10 cm and 17.5 cm, and the test piece was taken as an appearance retention tester (ART, manufactured by Daiei Kagaku Seiki Seisakusho Ltd.). Shape tester). The upper test piece was thoroughly moistened with gauze moistened with distilled water and then abraded for 10 minutes at a pressure of 7.36N. After the abrasion, the upper test piece was left in a standard state for 4 hours, and the degree of discoloration was graded by a discolored gray scale. If the grade was 3 or higher, the abrasion resistance was judged to be good, and if the grade was 4 or higher, the wear resistance was considered better.

L. Feeling Regarding the tubular knitting after hot water treatment produced in G above, "very soft" is S, "soft" is A, and "hard" by a majority vote of 5 inspectors who have 5 years or more of quality judgment experience. Was B, "very hard" was C, and A and S were acceptable. If there were the same number of votes, we narrowed down the choices to two classes and decided again by majority vote.

M. Improving stuffiness Regarding the tubular knitting after the hot water treatment produced in G above, by the majority vote of 5 inspectors who have 5 years or more of quality judgment experience, "no stuffiness" was given as S, "most stuffiness was found""No" was A, "feeling stuffy" was B, "extremely stuffy" was C, and A and S were passed. If there were the same number of votes, we narrowed down the choices to two classes and decided again by majority vote.

N. Durability A sample in which the tubular knitting after the hot water treatment prepared in the above G was subjected to 100 times of washing treatment according to the method shown in Appendix Table 103, which is specified in JIS L0217: 2010 (display symbols and handling methods for handling textile products). About the majority of 5 inspectors who have 5 years or more of quality judgment experience, "No crack or misalignment" is S, "There is almost no crack or misalignment" is A, "Crack or misalignment is There is B, "there are many cracks and misalignments" is C, and A and S are acceptable. If there were the same number of votes, we narrowed down the choices to two classes and decided again by majority vote.

(Production Example 1) Copolymerized polybutylene terephthalate composition 1.0 kg of 1,4-butanediol (manufactured by Tokyo Kasei) is heated to 100 ° C., and then 250 g of tetra-n-butoxy titanate (manufactured by Tokyo Kasei) is mixed to prepare a catalyst. A solution was obtained.

  45.3 kg of terephthalic acid (manufactured by Tokyo Kasei) as a dicarboxylic acid component, 44.2 kg of 1,4-butanediol as a diol component, and 135 g of the catalyst solution obtained by the above method as an esterification reaction catalyst were attached to a rectification column. It was charged in the esterification reaction tank. After the esterification reaction was started at a temperature of 160 ° C. under a reduced pressure of 93 kPa, the temperature was gradually raised, and finally the esterification reaction was performed for 270 minutes under the condition of a temperature of 235 ° C.

  60.0 kg of polyethylene glycol having a number average molecular weight of 10,000 g / mol (PEG10000 manufactured by Sanyo Chemical Industries), pentaerythritol-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenol) propionate) (manufactured by BASF, 180 g of IRGANOX 1010) was charged into the polymerization tank, and when the temperature of the polymerization tank reached 180 ° C. or higher, the reaction product obtained in the esterification reaction tank was transferred. After the temperature of the polymerization tank reached 250 ° C., 300 g of the catalyst solution obtained by the above method was added as a polycondensation reaction catalyst, and the polycondensation reaction was performed under the conditions of a temperature of 250 ° C. and a pressure of 100 Pa, and a predetermined stirring torque was obtained. At this point, the reaction system was purged with nitrogen to return to normal pressure to stop the polycondensation reaction, extruded in a strand form from a die, cooled in a water tank, and cut to obtain polybutylene terephthalate pellets obtained by copolymerizing 50% by weight of polyethylene glycol. Obtained.

  2,2′-dimethyl-2,2 ′-(2,4,8,10-tetraoxaspiro [5,5] undecane-3,9-diyl) dipropane-based on this copolymerized polybutylene terephthalate polymer 6.0 wt% of 1,1 ′ diyl bis [3- (3-t-butyl-4-hydroxy5-methylphenyl) propanoate] (made by ADEKA, Adeka Stab AO-80), 1,1′-biphenyl- 2.3% by weight of 4,4′-diylbis [bis (2,4-di-t-butylphenyl) phosphonous acid] (HOSTANOX P-EPQ, manufactured by Clariant Chemicals) was added, and L / D = 45 (L Is a screw length, D is a screw diameter), and a melt-kneading is performed for 3 minutes under the conditions of a cylinder temperature of 250 ° C., a rotation speed of 200 rpm, and a pressure of 10 kPa using a vent type twin-screw extruder having one vent portion. A copolymerized polybutylene terephthalate composition was obtained.

(Production Example 2) Copolymerized polyethylene terephthalate composition 51.9 kg of high-purity terephthalic acid (manufactured by Mitsui Chemicals) and ethylene glycol were placed in an esterification reaction tank in which 100 kg of bis (hydroxyethyl) terephthalate was charged in advance and the temperature was kept at 250 ° C. 23.3 kg of slurry (manufactured by Nippon Shokubai Co., Ltd.) was sequentially supplied over 4 hours, and the esterification reaction was carried out for 1 hour after the completion of the supply.

  60.0 kg of polyethylene glycol (PEG10000 manufactured by Sanyo Chemical Industries) having a number average molecular weight of 10,000 g / mol, pentaerythritol-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenol) propionate) (BASF, IRGANOX1010). ) Was charged into the polymerization tank, and when the polymerization tank temperature reached 180 ° C. or higher, 63.9 kg of the reaction product obtained in the esterification reaction tank was transferred to the polycondensation tank. After the temperature of the polymerization tank reached 250 ° C., 30.0 g of trimethyl phosphate was added as a polycondensation reaction catalyst, and 10 minutes later, 24.0 g of cobalt acetate tetrahydrate and 30.0 g of antimony trioxide were added. After 5 minutes, an ethylene glycol slurry of titanium oxide particles was added to the polymer in an amount of 0.3% by weight in terms of titanium oxide particles. After a further 5 minutes, the reaction system was depressurized to start the reaction. The temperature inside the reactor was gradually raised from 250 ° C. to 290 ° C., and the pressure was lowered to 40 Pa. The time required to reach the final temperature and final pressure was 60 minutes. When the predetermined stirring torque is reached, the reaction system is purged with nitrogen and returned to normal pressure to stop the polycondensation reaction, extruded in a strand form from the die, cooled in a water tank, and cut to copolymerize 50% by weight of polyethylene glycol. The pellets of the copolymerized polyethylene terephthalate were obtained.

  Based on this copolymerized polyethylene terephthalate polymer, 2,2'-dimethyl-2,2 '-(2,4,8,10-tetraoxaspiro [5,5] undecane-3,9-diyl) dipropane-1 , 1'diyl-bis [3- (3-t-butyl-4-hydroxy5-methylphenyl) propanoate] (ADEKA, Adeka Stab AO-80), 6.0% by weight, 1,1'-biphenyl-4 , 4′-diylbis [bisphosphonous acid bis (2,4-di-t-butylphenyl)] (manufactured by Clariant Chemicals, HOSTANOX P-EPQ) was added in an amount of 2.3% by weight, and L / D = 45 (L is Using a vent type twin-screw extruder having one vent part (screw length, D represents the screw diameter), melt kneading was performed for 3 minutes under the conditions of a cylinder temperature of 280 ° C., a rotation speed of 200 rpm, and a pressure of 10 kPa. A polymerized polyethylene terephthalate composition was obtained.

(Example 1)
Polybutylene terephthalate copolymerized with 50% by weight of polyethylene glycol having a number average molecular weight of 10000 g / mol (PEG10000 manufactured by Sanyo Kasei Co., Ltd.) prepared according to Production Example 1 was used as an island component and 5-sulfoisophthalic acid sodium salt as a sea component. Polyethylene terephthalate was obtained by copolymerizing 5 mol% and 2.0 wt% of polyethylene glycol having a number average molecular weight of 1000 g / mol (PEG1000 manufactured by Sanyo Chemical Industries). After vacuum-drying each at 150 ° C. for 12 hours, the island component and the sea component were supplied at a blending ratio of 10% by weight and 90% by weight to an extruder type composite spinning machine and melted separately, and at a spinning temperature of 275 ° C., A spun yarn was obtained by allowing the composite polymer stream to flow into a spinning pack incorporating a sea-island composite spinneret having 72 discharge holes, and discharging the composite polymer stream from the discharge holes at a discharge rate of 25 g / min. This spun yarn is cooled with a cooling air having a wind temperature of 20 ° C. and a wind speed of 20 m / min, an oil agent is applied and converged, and the spun yarn is taken up by a first godet roller rotating at 2700 m / min. The undrawn yarn of 92 dtex-72f was obtained by winding with a winder through a second godet roller that rotates at the same speed as the dead roller. Then, using a draw false twisting machine (twisting part: friction disk type, heater part: contact type), the obtained undrawn yarn is draw false twisted under the conditions of a heater temperature of 140 ° C. and a magnification of 1.4 times. A false twisted yarn having a 66 dtex-72f and a single fiber fineness of 0.92 dtex was obtained. The cross-sectional shape is as shown in FIG.

  Table 1 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The outermost layer had a thickness of 3.0 μm, and the difference in moisture absorption rate (ΔMR) after hot water treatment was 3.6%. The strength was as good as 3.1 cN / dtex, and the toughness was as good as 19.1. Also, there was one crack in the sea component, which was suppressed. The discoloration and fading after abrasion was grade 4, which was good, and the leveling properties, quality, texture, improvement of stuffiness, and durability were all acceptable levels.

(Examples 2 to 5)
Copolymerization polybutylene terephthalate prepared by changing the number average molecular weight and copolymerization rate of polyethylene glycol in Production Example 1 was used as an island component, and the sea-island composite ratio was changed to obtain a difference in moisture absorption rate after hot water treatment (ΔMR A false-twisted yarn was produced in the same manner as in Example 1 except that (4) was changed.

  Table 1 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. In each case, the single fiber fineness was 0.92 dtex, and the outermost layer thickness was 2.5 to 4.5 μm. In all cases, the strength was 2.5 cN / dtex or more, and the toughness was 16.5 or more. In addition, the number of cracks in the sea component was 5 or less, and the cracks were suppressed. The discoloration and discoloration after abrasion were all grade 3 or better, and the leveling properties, quality, texture, stuffiness improvement, and durability were all acceptable levels.

(Example 6)
Copolymerized polybutylene terephthalate prepared by using poly (ethylene glycol) methyl ether having a number average molecular weight of 10,000 g / mol (manufactured by SIGMA-ALDRICH) in Production Example 1 was used as an island component, and 5% by weight of the island component and 95% of the sea component were used. A false twisted yarn was produced in the same manner as in Example 1 except that the single fiber fineness was changed to 0.50 dtex by changing the weight% and the number of filaments to 132.

  Table 1 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The outermost layer thickness was 2.6 μm, and the moisture absorption difference (ΔMR) after hot water treatment was 2.3%. The strength was 2.5 cN / dtex, and the toughness was 16.6, which was good. Also, the sea component was cracked at four locations, which were suppressed. The discoloration and fading after abrasion was as good as grade 3, and the leveling properties, quality, texture, improvement of stuffiness, and durability were all acceptable levels.

(Examples 7 to 9)
A false twisted yarn was produced in the same manner as in Example 1 except that the single fiber fineness was changed by changing the number of filaments.

  Table 2 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. In each case, the outermost layer had a thickness of 2.5 to 4.5 μm, and the moisture absorption difference (ΔMR) after the hot water treatment was 3.6%. In all cases, the strength was 2.5 cN / dtex or more, and the toughness was 16.5 or more. Moreover, the cracks of the sea component were suppressed to two or less in all cases. The discoloration and discoloration after abrasion were all grade 3 or better, and the leveling properties, quality, texture, stuffiness improvement, and durability were all acceptable levels.

(Example 10)
A false-twisted yarn was produced in the same manner as in Example 1 except that the outermost layer thickness was changed to 2.5 μm by changing the island component by 19% by weight and the sea component by 81% by weight.

  Table 2 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The single fiber fineness was 0.92 dtex, and the moisture absorption difference (ΔMR) after hot water treatment was 8.5%. The strength was 2.5 cN / dtex, and the toughness was 16.6, which was good. Also, the sea component was cracked at four locations, which were suppressed. The discoloration and fading after abrasion was as good as grade 3, and the leveling properties, quality, texture, improvement of stuffiness, and durability were all acceptable levels.

(Examples 11 to 12)
In Production Example 1, the copolymerized polybutylene terephthalate prepared by using poly (ethylene glycol) methyl ether having a number average molecular weight of 10,000 g / mol (manufactured by SIGMA-ALDRICH) was used as an island component, the number of filaments was set to 44, and the sea-island composite ratio was set. Was changed to prepare a false twisted yarn in the same manner as in Example 1 except that the outermost layer thickness was changed.

  Table 3 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. In both cases, the single fiber fineness was 1.50 dtex, and the moisture absorption difference (ΔMR) after hot water treatment was 2.0 to 10.0%. In all cases, the strength was 2.5 cN / dtex or more, and the toughness was 16.5 or more. In addition, the number of cracks in the sea component was 0, which was suppressed. The discoloration and discoloration after abrasion were all 4 or higher, which was good, and the leveling properties, quality, texture, improvement of stuffiness, and durability were all acceptable levels.

(Examples 13 to 14)
A false twisted yarn was produced in the same manner as in Example 1 except that the composite spinneret type was changed and the fiber cross section shown in Fig. 1 (b) in Example 13 and Fig. 1 (c) in Example 14 was used.

  Table 3 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. In each case, the single fiber fineness was 0.92 dtex, the outermost layer thickness was 2.5 to 4.5 μm, and the moisture absorption difference (ΔMR) after hot water treatment was 3.8% in all cases. In all cases, the strength was 2.5 cN / dtex or more, and the toughness was 16.5 or more. In addition, discoloration and discoloration after abrasion were all grade 4, which was good, and the texture, improvement in stuffiness, and durability were all acceptable levels.

(Example 15)
In the same manner as in Example 1 except that the copolymerized polyethylene terephthalate prepared in Production Example 2 so that polyethylene glycol having a number average molecular weight of 10000 g / mol (PEG10000 manufactured by Sanyo Kasei Co., Ltd.) was copolymerized at 50% by weight was used as the island component. A false twisted yarn was produced.

  Table 3 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The single fiber fineness was 0.92 dtex, the outermost layer thickness was 3.0 μm, and the moisture absorption difference (ΔMR) after hot water treatment was 3.7%. The toughness was as good as 16.6. Also, there was one crack in the sea component, which was suppressed. The discoloration and fading after abrasion was grade 4, which was good, and the leveling properties, quality, texture, improvement of stuffiness, and durability were all acceptable levels.

(Example 16)
Polyethylene glycol having a number average molecular weight of 8300 g / mol in Production Example 1 (PEG 10000 manufactured by Sanyo Kasei Co., Ltd.) was used, and the copolymerized polybutylene terephthalate prepared so as to be 30% by weight was used as the island component, and the island component was 30%. A false twisted yarn was produced in the same manner as in Example 1 except that the weight%, the sea component was 70% by weight, and the number of filaments was changed to 44.

  Table 3 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The single fiber fineness was 1.50 dtex, the outermost layer thickness was 2.5 μm, and the moisture absorption difference (ΔMR) after hot water treatment was 3.1%. The strength was as good as 2.7 cN / dtex. Also, there was one crack in the sea component, which was suppressed. The discoloration and fading after abrasion was as good as grade 3, and the leveling properties, quality, texture and stuffiness improvement were all acceptable levels.

(Example 17)
Ester-reactive silicone (polyethylene terephthalate copolymerized with 1.5 mol% of 5-sulfoisophthalic acid sodium salt and 2.0 wt% of polyethylene glycol having a number average molecular weight of 1000 g / mol (PEG1000 manufactured by Sanyo Chemical Industries)) A false-twisted yarn was produced in the same manner as in Example 1 except that a polymer containing 5.0% by weight of FM-4411) was used as the sea component.

  Table 3 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The single fiber fineness was 0.92 dtex, the outermost layer thickness was 3.0 μm, and the moisture absorption difference (ΔMR) after hot water treatment was 2.4%. The discoloration and fading after abrasion was as good as grade 3, and the texture and stuffiness improvement were all acceptable levels.

(Example 18)
Polyethylene glycol having a number average molecular weight of 10,000 g / mol (PEG10000 manufactured by Sanyo Chemical Industries) and pentaerythritol-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenol) propionate) (BASF, IRGANOX1010) were added. After that, trimethyl trimellitate (manufactured by Tokyo Kasei) was added to the polymerization tank in an amount of 1.6 kg (3 mol%), and 50 wt% of polyethylene glycol having a number average molecular weight of 10000 g / mol was prepared in the same manner as in Production Example 1. A false twisted yarn was prepared in the same manner as in Example 1 except that polymerized polybutylene terephthalate was used as the island component.

  Table 3 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The single fiber fineness was 0.92 dtex, the outermost layer thickness was 3.0 μm, and the moisture absorption difference (ΔMR) after hot water treatment was 3.6%. The discoloration and fading after abrasion was as good as grade 3, and the texture and stuffiness improvement were all acceptable levels.

(Comparative Example 1)
Polyethylene glycol having a number average molecular weight of 3400 g / mol (PEG4000S manufactured by Sanyo Kasei Co., Ltd.) in Production Example 1 was used, and the copolymerized polybutylene terephthalate prepared so as to be 30% by weight was used as the island component, and the island component was 15 A false-twisted yarn was produced in the same manner as in Example 1 except that the weight% and the sea component were changed to 85% by weight, and the moisture absorption difference (ΔMR) after hot water treatment was changed to 1.9%.

  Table 4 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. After the scouring and the hot water treatment, the hygroscopicity was low, and a stuffy feeling was felt.

(Comparative example 2)
Polyethylene glycol having a number average molecular weight of 20000 g / mol (PEG 20000 manufactured by Sanyo Kasei Co., Ltd.) in Production Example 1 was used, and the copolymerized polybutylene terephthalate prepared so that 50% by weight was copolymerized was used as the island component, and the island component was 19 A false-twisted yarn was produced in the same manner as in Example 1 except that the weight% and the sea component were changed to 81% by weight, and the moisture absorption difference (ΔMR) after hot water treatment was changed to 11.0%.

  Table 4 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The sea component is extremely cracked due to the volume swelling of the hygroscopic polymer of the island component, and many spots of dyeing (level dyeing property) and fluff caused by the cracking of the sea component are seen, and the level dyeing property and grade are extremely poor. there were.

(Comparative example 3)
Copolymerized polybutylene terephthalate prepared by using poly (ethylene glycol) methyl ether (manufactured by SIGMA-ALDRICH) having a number average molecular weight of 10,000 g / mol in Production Example 1 was used as an island component, and 4% by weight of the island component and 96 of the sea component were used. A false-twisted yarn was produced in the same manner as in Example 1 except that the weight% and the number of filaments were changed to 148 and the single fiber fineness was changed to 0.45 dtex.

  Table 4 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. It has a strength of 1.3 cN / dtex, which is inferior in mechanical properties, many sea component cracks, and many spots of dyeing (level dyeing) and fluff caused by the cracks of sea components are seen. Was inferior to

(Comparative example 4)
A false twisted yarn was produced in the same manner as in Example 1 except that the number of filaments was changed to 36 and the single fiber fineness was set to 1.83 dtex.

  Table 4 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The cloth was hard and the texture was inferior.

(Comparative example 5)
A false-twisted yarn was produced in the same manner as in Example 1 except that the island component was changed to 22% by weight, the sea component was changed to 78% by weight, and the outermost layer thickness was changed to 2.3 μm.

  Table 4 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. Since the thickness of the outermost layer was small, discoloration and discoloration after abrasion were grade 2, which was inferior in abrasion resistance.

(Comparative example 6)
A false twisted yarn was produced in the same manner as in Example 1 except that the island component was changed to 2% by weight, the sea component was changed to 98% by weight, the number of filaments was changed to 44, and the outermost layer thickness was changed to 4.9 μm.

  Table 3 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. After the scouring and the hot water treatment, the hygroscopicity was low, and a stuffy feeling was felt.

(Comparative Example 7)
A false twisted yarn was produced in the same manner as in Example 1 except that the island component was changed to polyetheramide (PEBAX MH1657 manufactured by Arkema).

  Table 4 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The discoloration after abrasion was grade 2, which was inferior in abrasion resistance.

(Comparative Example 8)
A false twisted yarn was produced in the same manner as in Example 1 except that polyethylene terephthalate obtained by copolymerizing 80% by weight of polyethylene glycol (manufactured by SIGMA-ALDRICH) having a number average molecular weight of 4000 g / mol produced according to Production Example 2 was used as the island component. .. A false-twisted yarn was produced in the same manner as in Example 1 except that this polyester composition was used as the island component.

  Table 4 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The hygroscopic polymer was often eluted by the hot water treatment, and the hygroscopicity was significantly decreased after the hot water treatment, and the hygroscopicity was low and the stuffiness was felt.

(Comparative Example 9)
Polybutylene terephthalate pellets and polyethylene glycol having a number average molecular weight of 10,000 g / mol (PEG6000S manufactured by Sanyo Chemical Industries) at a ratio of 50% by weight and 50% by weight, L / D = 45 (L is a screw length, D is a screw diameter. ), Using a vent type twin-screw extruder having one vent part, melt kneading is carried out for 3 minutes under the conditions of a cylinder temperature of 250 ° C., a rotation speed of 110 rpm, and a pressure of 10 kPa, and polybutylene is kneaded with 50% by weight of polyethylene glycol. Pellets of terephthalate were obtained. The pellets were remelted to give 2,2'-dimethyl-2,2 '-(2,4,8,10-tetraoxaspiro [5,5] undecane-3,9-diyl) dipropane-1,1'. Diyl = bis [3- (3-t-butyl-4-hydroxy5-methylphenyl) propanoate] (ADEKA, Adeka Stab AO-80) 6.0% by weight, 1,1′-biphenyl-4,4 ′ -Diyl bis [bis (2,4-di-t-butylphenyl phosphonite)] (manufactured by Clariant Chemicals, HOSTANOX P-EPQ) 2.3 wt% was compounded, cylinder temperature 250 ° C, rotation speed 200 rpm, pressure 10 kPa. Melt kneading was carried out for 3 minutes under the conditions described above to obtain a polyester composition. A false twisted yarn was produced in the same manner as in Example 1 except that the thus obtained polyester composition was used as the island component.

  Table 4 shows the evaluation results of the fiber properties and the fabric properties of the obtained fibers. The hot water treatment caused a large amount of polyethylene glycol to be eluted into the hot water, and after the hot water treatment, the hygroscopicity was significantly reduced, and the hygroscopicity was low, and a stuffy feeling was felt.

(Comparative Example 10)
Number average molecular weight 4000 g / mol polyethylene glycol (manufactured by SIGMA-ALDRICH) produced according to Production Example 2 30% by weight of copolymerized polyethylene terephthalate and polyethylene terephthalate pellets in a ratio of 30% by weight and 70% by weight, with respect to this polymer, 2,2'-Dimethyl-2,2 '-(2,4,8,10-tetraoxaspiro [5,5] undecane-3,9-diyl) dipropane-1,1' diyl = bis [3- ( 3-t-butyl-4-hydroxy5-methylphenyl) propanoate] (ADEKA, Adeka Stab AO-80), 6.0% by weight, 1,1′-biphenyl-4,4′-diylbis [bisphosphonous acid bisulfite (2,4-di-t-butylphenyl)] (CLARIANT CHEMICALS, HOSTANOX P-EPQ) 2.3% by weight is compounded and L / D = 45 (L is screw length, D is screw diameter). Using a vent type twin-screw extruder having one vent part, melt kneading was carried out for 3 minutes under conditions of a cylinder temperature of 280 ° C., a rotation speed of 200 rpm and a pressure of 10 kPa to obtain a polyester composition. Table 4 shows the evaluation results of the fiber properties and the fabric properties of the resulting fibers prepared by false-twisting yarns in the same manner as in Example 1 except that this polyester composition was used as the island component. The hot water treatment caused a large amount of polyethylene glycol to be eluted into the hot water, and after the hot water treatment, the hygroscopicity was significantly reduced, and the hygroscopicity was low, and a stuffy feeling was felt.

  The hygroscopic ultrafine composite fiber obtained in the present invention is excellent in high hygroscopicity and abrasion resistance even after hot water treatment such as dyeing, and moreover, because it has a good texture when formed into a fiber structure, it is comfortable. It can be suitably used in applications where properties and qualities are required. Specific examples include general clothing applications, sports clothing applications, bedding applications, interior applications, and material applications.

1. Sea (sheath) component 2. Island (core) component 3. Fiber radius 4. 4. A circumscribed circle connecting the points with the longest distance from the fiber center in the island (core) component arranged on the outermost periphery. 5. The radius of the circumscribed circle that connects the vertices of the point with the longest distance from the fiber center in the island (core) component arranged on the outermost periphery. Outermost layer thickness 7. Air layer

Claims (5)

A hygroscopic ultrafine composite fiber having the following characteristics (1) to (5).
(1) The polyester polymer completely covers the hygroscopic polymer. (2) The hygroscopic polymer is a copolyester polymer. (3) The moisture absorption difference (ΔMR) after hot water treatment is 2.0-10.0%
(4) Single fiber fineness of 0.50 to 1.50 dtex
(5) Outermost layer thickness is 2.5 to 4.5 μm
The outermost layer thickness is the difference between the radius of the fiber and the radius of the circumscribed circle connecting the points with the longest distance from the fiber center in the island (core) component arranged on the outermost periphery, and is present in the outermost layer. Indicates the thickness of the sea (sheath) component.   The hygroscopic ultrafine composite fiber according to claim 1, wherein the composite form is a sea-island type.   The hygroscopic ultrafine composite fiber according to claim 1 or 2, wherein the polymer having hygroscopicity is a copolymerized polybutylene terephthalate.   The hygroscopic ultrafine composite fiber according to any one of claims 1 to 3, which has a toughness of 16.5 or more. A fiber structure comprising the hygroscopic ultrafine composite fiber according to any one of claims 1 to 4 at least in part.