JP2013185279A - Moisture-absorbing/releasing polyester fiber and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moisture-absorbing/releasing polyester fiber that has high moisture-absorbing/releasing properties and mechanical properties, has small fineness unevenness with no affect on process passability during high-order processing, and causes no black- or yellow-coloring during production which may cause a problem when it is used for clothing.SOLUTION: The polymer alloy fiber includes polyester and poly(n-vinylacetamide lactam) in a ratio of 97:3 to 75:25. The poly(n-vinylacetamide lactam) is finely dispersed in a fiber cross section with having a dispersion diameter of 500 nm or less. The fiber has a moisture-absorbing/releasing parameter (ΔMR) of 1.0% or more, a strength of 2.0 cN/dtex or more, a toughness of 15 or more, a fineness unevenness U%(n) of 1.5 or less, a color tone L value of 70 or more, and a b value of 10 or less.

Description

  The present invention relates to a polyester fiber having hygroscopic properties and a method for producing the same.

  Polyester fibers typified by polyethylene terephthalate and polybutylene terephthalate are excellent in mechanical strength, heat resistance, etc., and are therefore widely used mainly for clothing applications. However, since these polyester fibers have extremely low moisture absorption and release properties, when used in fields where they are directly touched or worn close to the skin, such as inners, pants, and sports clothing. However, since it causes stuffiness and stickiness due to sweating from the skin and is inferior in terms of comfort compared to natural fibers with high moisture absorption and desorption properties, advancement into these fields is limited.

  For this reason, for example, as described in Patent Document 1, a technique has been proposed in which a hygroscopic component is imparted to a fabric made of polyester fiber by high-order processing. However, this method has a problem that the texture of the fabric becomes hard and the washing durability is poor.

  Therefore, in order to impart moisture absorption / release properties to the polyester fiber itself, for example, as described in Patent Documents 2 to 4, a polymer having moisture absorption / release properties is used as a core component, and the core is covered with polyester as a sheath component. A sheath type composite fiber has been proposed. Although this method improves moisture absorption and release properties, during hydrothermal treatment such as dyeing, the sheath is distorted by volume expansion due to moisture absorption and swelling of the core, resulting in cracks and cracks (sheath cracks) on the fiber surface. However, there are disadvantages such as not only lowering the process but also causing a process trouble. Attempts have been made to absorb the volume expansion of the core part and suppress sheath cracking by providing a hollow part in the fiber, but this has caused a problem that the product value is liable to be peeled off at the interface.

  Therefore, in order to suppress the sheath cracking by reducing the absolute value of the volume change due to the swelling of the hygroscopic polymer, a technique for dispersing the hygroscopic polymer in the polyester has been proposed as described in Patent Document 5, for example. . However, in this technology, a polymer obtained by copolymerizing polyoxyalkylene glycol and polyester is used as the hygroscopic polymer. Therefore, it is necessary to increase the island component ratio in order to fully exhibit the hygroscopic property. There is a problem that the yarn becomes unstable and the yarn breakage increases or the fineness unevenness in the longitudinal direction of the obtained fiber becomes large.

  On the other hand, as described in Patent Document 6, for example, a technique has been proposed in which a hygroscopic component is used alone and dispersed in polyester without copolymerization. However, this technique relates to polyamide, and it has been impossible to reproduce the elasticity and stiffness unique to polyester. Moreover, the technique which applies this technique to polyester is described in patent document 7, for example. However, this document does not describe a specific production method for fibers, and the examples also relate to films. When the fiber was produced based on the literature, the fiber was colored black, the smoke during operation and the yellowness of the fiber were increased, the spinning operability was frequently caused by yarn breakage, and the fineness spots in the longitudinal direction of the fiber were Many problems occurred, such as being large, the yarn layer ruptured during winding, and swelled during storage of the wound yarn, resulting in poor unwindability during drawing, resulting in poor drawability and large fineness.

JP 2002-69846 A Japanese Patent Application Laid-Open No. 5-209316 JP-A-6-136620 JP-A-9-111579 JP 2004-277911 A JP-A-55-4852 JP 2002-155425 A

  It is an object of the present invention to provide a polyester fiber having good moisture absorption / release properties and strength, little longitudinal fineness unevenness, and excellent mechanical properties, and a method for producing the same.

  The above-mentioned problems are that the fiber is 3 to 25% by weight of poly (N-vinyl lactam), the dispersion diameter in the fiber cross section is finely dispersed at 500 nm or less, and the moisture absorption / release parameter (ΔMR) is 1.0% or more. Moisture absorption and desorption characterized by strength of 2.0 cN / dtex or more, toughness of 15 or more, fineness unevenness U% (n) of 1.5 or less, color tone L value of 70 or more, b value of 10 or less Can be solved by polyester fiber.

  The polyester fiber obtained by the present invention has sufficient moisture absorption and release properties to obtain wearing comfort, and has characteristics such as small fineness spots, high L value, and low b value. Therefore, the fiber is excellent in uniform dyeability and color developability and is suitable for use as clothing.

  The moisture-absorbing / releasing polyester fiber of the present invention is obtained by fiberizing a polymer in which polyester and poly (N-vinyl lactam) are alloyed. Here, alloying is an operation of mixing a plurality of polymers to give new characteristics. The polymer alloy fiber of the present invention has a sea-island structure in which polyester is a sea component and poly (N-vinyl lactam) is an island component.

  As the polyester, either aromatic polyester or aliphatic polyester may be used. Examples of the aromatic polyester include those in which the acid component is terephthalic acid and / or isophthalic acid and the diol component is at least one of aliphatic diols such as ethylene glycol, trimethylene glycol, and tetramethylene glycol. Among these, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate and the like are preferable. A part of the aromatic polyester may be substituted with a copolymerization component. Examples of the copolymerization component include phthalic acid, methylterephthalic acid, methylisophthalic acid, sulfoisophthalate, succinic acid, adipic acid, sebacic acid, and the like. Is mentioned. Further, the above aromatic polyester may be copolymerized with trimesic acid, trimellitic acid or the like as a branching component. Examples of the aliphatic polyester include homopolymers of hydroxycarboxylic acids such as glycolic acid and lactic acid, and copolymers thereof. Of these, polyglycolic acid and polylactic acid are preferred.

  Conventionally, antimony trioxide has been widely used as a catalyst used in the polycondensation of such polyester. In this case, the content of antimony atoms in the polyester is 100 ppm or more, but it is used in the present invention. The polyester preferably has an antimony atom content of 50 ppm or less. In this case, the antimony atom content of the hygroscopic polyester fiber is also 50 ppm or less. The antimony atom content in the polyester is more preferably 30 ppm or less. As described above, there has been a problem that the alloy polymer is colored black by blending polyester and poly (N-vinyl lactam). However, as a result of intensive studies, the present inventors have found that the cause of this coloring is antimony. Ascertaining that it is a black foreign substance due to the reaction between atoms and poly (N-vinyl lactam), and using a polyester having an antimony atom content of 50 ppm or less, the alloy polymer can be prevented from being colored black, and the fibers It has been found that the color tone L value can be increased to 70 or more. The antimony atom content in the polyester can be reduced to 50 ppm or less by using a polymerization catalyst other than antimony (such as titanium, tin, or germanium), or by using these in combination with an antimony polymerization catalyst. . It can also be achieved by blending a polyester using an antimony polymerization catalyst and a polyester using a polymerization catalyst other than antimony.

  Furthermore, it is preferable that melting | fusing point of polyester is 255 degrees C or less, and it is more preferable that it is 150 to 240 degreeC. Poly (N-vinyl lactam) yellows due to thermal degradation at high temperatures, causing the color tone b value of the fiber to deteriorate. For this reason, by using polyester having a melting point of 255 ° C. or less, the kneading temperature and the spinning temperature can be kept low, the thermal deterioration of poly (N-vinyl lactam) can be suppressed, and the deterioration of the color tone b value of the fiber can be suppressed. On the other hand, many poly (N-vinyl lactams) are amorphous with a glass transition temperature of about 170 ° C., so it is necessary to process at a higher temperature during kneading and spinning. It is preferable because thermal degradation of the polyester can be suppressed.

  Examples of poly (N-vinyl lactam) include polymers of N-vinyl lactams such as N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, and N-vinylcaprolactam. The poly (N-vinyl lactam) used in the present invention is preferably polyvinyl pyrrolidone, which is a polymer of N-vinyl-2-pyrrolidone, because it has a small steric hindrance and can easily adsorb and release water molecules. Polyvinyl pyrrolidone generally has a weight average molecular weight of 50,000 to 2.5 million, preferably a weight average molecular weight of 10,000 to 1,000,000, and a weight average molecular weight of 30,000 to 500,000. Is more preferable. With a weight average molecular weight of 10,000 or more, thermal stability is increased, bleeding out during melt spinning can be suppressed, and elution of polyvinylpyrrolidone during high-order processing and use as a product can be suppressed. The moisture absorption / release property can be improved. In addition, when the weight average molecular weight is 1,000,000 or less, the viscosity of the alloy polymer is increased, and it is suitably suppressed that the dispersibility is reduced by aggregation in the polyester and the polymer pressure applied to the apparatus during spinning is increased. it can.

  In the present invention, it is necessary to use a polymer alloy fiber having a sea-island structure in which polyester is the sea and poly (N-vinyl lactam) is a fine island. By using polyester as a sea component, polyester having high mechanical properties can bear the mechanical properties of the fibers, and the fibers can have high mechanical properties. In addition, by using poly (N-vinyl lactam) as an island component, the exposure of the poly (N-vinyl lactam) having low water resistance to the fiber surface is suppressed, and the poly at the time of high-order processing and use as a product. The elution of (N-vinyl lactam) can be suppressed and the moisture absorption / release property can be improved.

  The ratio of each component when the total amount of polyester and poly (N-vinyl lactam) is 100 parts by weight is 75 parts by weight or more and 97 parts by weight or less of polyester, 25 parts by weight or more and 3 parts by weight of poly (N-vinyl lactam) It is necessary to be below, preferably 80 to 95 parts by weight of polyester, 5 to 20 parts by weight of poly (N-vinyl lactam).

  Moisture absorption and desorption can be achieved by setting poly (N-vinyl lactam) to 3 parts by weight or more. On the other hand, by setting the poly (N-vinyl lactam) to 25 parts by weight or less, it is possible to suppress the fineness unevenness in the longitudinal direction caused by the bulging of the spinning line generated by the ballast effect during fiber production.

  In the fiber of the present invention, the dispersion diameter of the island component in the fiber cross section needs to be 500 nm or less, preferably 10 nm or more and 300 nm or less, and more preferably 20 nm or more and 150 nm or less. By setting the dispersion diameter to 500 nm or less, the specific interfacial area of the sea-island interface can be made sufficiently large, and the sheath cracking of the sea component due to the volume change due to the hygroscopic swelling of the island component can be suppressed. The moisture release rate is increased, and the moisture absorption / release property is excellent with quick response to environmental changes. Furthermore, among island component polymers, the proportion of island component polymers that have exposed portions on the fiber surface layer is reduced, and the moisture absorption and release due to elution of island component polymers during high-order processing and as a product is suppressed. Can do. In addition, if the dispersion diameter of the island component is large, the island component stretched at the time of discharge of the die also increases the force to return to a spherical shape due to the interfacial tension between the polymers after discharge, and the number of discharge hole diameters called the ballast effect directly under the discharge holes A bulge having a double diameter is generated. For this reason, thick and thin abnormalities are likely to occur in the thinning deformation process during spinning, and quality problems such as fineness unevenness occur in the longitudinal direction of the yarn, and yarn breakage occurs when the thinness is large. Further, by setting the dispersion diameter to 10 nm or more, it is possible to suppress shear applied to the polymer at the time of kneading, and it is possible to suppress deterioration in physical properties and color tone due to molecular chain cleavage.

  The hygroscopic parameter ΔMR needs to be 1.0% or more. Here, ΔMR is a driving force for obtaining comfort by releasing moisture in the clothes to the outside air when the clothes are worn, and 30 ° C. × 90% when performing light to medium work or light to medium exercise It is a moisture absorption rate difference between the temperature and humidity in clothes represented by RH and the outside temperature and humidity represented by 20 ° C. × 65% RH. In the present invention, this ΔMR is used as a parameter as a scale for evaluating moisture absorption / release properties. The larger ΔMR corresponds to the higher moisture absorption / release properties and the better the comfort when worn. When the ΔMR is 1.0% or more, the moisture absorption / release performance and comfort of the fiber are good. ΔMR is preferably 1.5% or more, and more preferably ΔMR 2.0% or more and 5.0 or less. On the other hand, in order to increase ΔMR, it is necessary to increase the blend amount of poly (N-vinyl lactam), but by setting ΔMR to 5.0 or less, fineness spots that do not affect the process passability can be obtained. It is preferable.

  The strength needs to be 2.0 cN / dtex or more, and the toughness needs to be 15 or more. The strength is preferably 2.5 cN / dtex or more and 4.5 cN / dtex or less, and the toughness is 17 or more and 27 or less. When the strength is 2.0 cN / dtex or more, the strength of the cloth is high, and it is suitable for thinning, high density and light weight of the cloth for clothing. When the strength is 4.5 cN / dtex or less, generation of fuzz due to the stretch ratio being too high can be suppressed, and process passability is improved. Also, in order to increase the fiber strength, it is common to increase the draw ratio at the time of production, but in this way, the strength is increased, but the elongation is decreased, fluff is likely to occur, processes such as weaving Passability is poor. For this reason, to obtain high strength while maintaining sufficient elongation, the toughness needs to be 15 or more, preferably 17 or more, and more preferably 20 or more. In addition, there is a limit to improving toughness by optimizing the yarn-making conditions. To obtain toughness exceeding this, it is necessary to use polyester with a very high molecular weight as a raw material, so toughness can be reached with general-purpose polyester. 27 or less is preferable.

  The fineness unevenness U% (n) in the longitudinal direction of the fiber of the present invention needs to be 1.5% or less, preferably 1.0% or less, and more preferably 0.8% or less. If it is 1.5% or less, dyed spots after dyeing can be suppressed. In the dyeing process, it is known that a large portion of fineness exhausts a large amount of dye due to small molecular orientation. For this reason, if the fineness is uneven, it will cause dyed spots.

  The color tone L value needs to be 70 or more. The color tone L value is a parameter representing the lightness of the fiber, and when the L value is 70 or more, the color developability when dyeing is improved. For this reason, it is preferable that L value is 80 or more, and it is more preferable in it being 85 or more.

  The color tone b value needs to be 10 or less. The color tone b value is a parameter representing the chromaticity of the fiber, and the yellow value is stronger as the b value is larger. When the b value is 10 or less, the yellow color is small, the appearance color tone is excellent, and the fiber is suitable for clothing. For this reason, the b value is preferably 8 or less, and more preferably 5 or less.

  The moisture-absorbing / releasing polyester fiber of the present invention having such characteristics can be used after being processed into a fiber structure such as a napped body such as a woven fabric, a knitted fabric, a non-woven fabric, or a pile woven fabric, or padded cotton. Examples of uses of the fiber structure include clothing, industrial materials, interior products, and the like. Among them, in particular, it can be effectively used in a field where the skin is directly touched or worn in a state close to the skin side, such as an inner, a middle garment, and sports clothing.

The manufacturing method of the moisture absorption / release polyester fiber of this invention is shown below.
A polyester having a melting point of 255 ° C. or less and an antimony atom content of 50 ppm or less, and poly (N-vinyl lactam) are 180 ° C. so that the weight ratio is 97: 3 to 75:25 and the dispersion diameter in the fiber cross section is 500 nm or less. The mixture was melt-kneaded at a temperature of 270 ° C. or lower, cooled once, and then formed into chips. Feed into the spinning device. A kneading apparatus used at this time is preferably a twin screw extruder having a screw diameter of 40 mm or more and an L / D of 35 or more. After the polymer sent to the spinning device is melted and weighed, it is passed through a filter made of a metal non-woven fabric placed on the base, the fiber discharged from the base is cooled and lubricated, and then taken over at a rate of 300 m / min. It guide | induces to a extending | stretching process, it extends | stretches in 1 step | paragraph or 2 steps | paragraphs at extending | stretching temperature 30 degreeC or more and 140 degrees C or less, and winds up.

Details of each manufacturing process are as follows.
Regarding the raw materials, in the combination of the polyester and poly (N-vinyl lactam) described above, the total amount of the polyester and poly (N-vinyl lactam) is 100 parts by weight, and the polyester is 75 to 97 parts by weight, poly (N-vinyl lactam) ) It is necessary to weigh and blend each as 25 to 3 parts by weight. At this time, the polyester and poly (N-vinyl lactam) that easily absorb moisture are previously dried at 80 to 150 ° C. under reduced pressure or in a nitrogen atmosphere, and after drying, are stocked in a moisture absorption prevention container or the like. The moisture absorption before melt kneading is preferably 0.05% by weight or less, more preferably 0.02% by weight or less, and most preferably 0.008% by weight or less.

  A preferable apparatus used in the kneading step is a twin screw extruder having a screw diameter of 40 mm or more and L / D35 or more. For the reasons described above, the moisture-absorbing / releasing polyester fiber of the present invention needs to have an island component dispersion diameter of 500 nm or less in the fiber cross section, and any other twin-screw extruder as long as it is a kneading apparatus capable of achieving this. Alternatively, a single screw extruder may be used. On the other hand, it is difficult to reduce the island component dispersion diameter in the fiber cross section to 500 nm or less using a kneading roll or a Banbury mixer. Moreover, after kneading | mixing, you may make into a chip | tip once and may send continuously to a spinning apparatus as it is.

  The jacket temperature at the time of kneading in melt extrusion is Tm + 5 or more and Tm + 40 ° C. or less, based on the melting point of polyester (hereinafter referred to as Tm), and the shear rate of kneading is 300 (1 / sec) or more and 9800 (1 / sec) or less. In a biaxial extrusion kneader (two axes in the same direction, shaft diameter 40 mm, L / D35), the shaft rotation speed is preferably 100 rpm or more. By setting the jacket temperature and the shear rate within this range, it is possible to obtain a highly uniform alloy phase structure and to sufficiently reduce the domain size of the island component. Also, the jacket temperature is preferably low in order to suppress the coloring of the resin. In particular, the poly (N-vinyl lactam) used in the present invention may be thermally deteriorated, colored yellow or smoked at a high temperature. Therefore, Tm + 5 ° C. or higher and Tm + 25 ° C. or lower is more preferable. Similarly, in order to maintain the above alloy phase structure and prevent coloring, the spinning temperature is preferably as low as possible, and is preferably in the range of Tm + 20 ° C. to Tm + 50 ° C. In addition, when using a poly (N-vinyl lactam) powder that is amorphous and has a low glass transition temperature, it is preferable to cool the charging portion. By cooling the charging unit, it is possible to prevent a trouble that the powder is fused in the charging unit and cannot be stably supplied.

  In the spinning process, a high-mesh filter layer (# 100 to # 200) or a non-woven filter with a small filter diameter (in order to control the dispersion diameter of the island component by suppressing the re-aggregation of the island domains in the spin pack ( You may arrange | position a filtration diameter 5-30 micrometers on a nozzle | cap | die. Among them, a multilayer filter made of a metal nonwoven fabric having a plurality of wire diameters is most effective for controlling the dispersion diameter of island components.

  The discharged filament may be a monofilament or a multifilament. As the shape of the die discharge hole, a known round cross-section, Y cross-section, triangular cross-section, square cross-section, flat cross-section, or hollow cross-section thereof can be used, and a suitable one can be selected according to the application. . Among these, an irregular cross section other than the round cross section is preferable because the specific surface area of the fiber is increased and the moisture absorption / release rate is increased.

  The cooling method under the base may be a uniflow type chimney that cools from one direction, or an annular chimney that applies cooling air from the inside to the outside of the yarn, or from the outside to the inside of the yarn, but preferably the inside of the yarn An annular chimney that is cooled from the outside to the outside is preferable in that uniform cooling is possible. At this time, it is desirable to cool the cooling air by applying a cooling gas to the multifilament from a direction orthogonal to the multifilament. The speed of the cooling air at this time is preferably 0.2 m / second or more and 1 m / second or less, and more preferably 0.3 m / second or more and 0.8 m / second or less. Further, the temperature of the cooling air is preferably low in order to achieve uniform cooling, but it is realistic and preferable to be 15 ° C. or more and 25 ° C. or less in consideration of the temperature adjustment cost of the cooling air.

  The spun multifilament is coated with a surface by supplying a known spinning oil. The amount of the oil attached at this time is 0.3 to 3% by weight as a pure oil to the yarn. As the spinning oil, a water-containing oil widely used as an oil for polyester fibers for clothing may be used, or a non-water-containing oil may be used. However, as will be described later, in the moisture-absorbing / releasing polyester fiber of the present invention, it is necessary to properly use it depending on the fiber production method.

  In the take-up process, the take-up is performed at a spinning speed of 300 m / min or more, and is wound up once or continuously drawn. Productivity can be improved by winding up at 300 m / min or more. A preferable spinning speed is 500 m / min or more and 3000 m / min or less. By spinning at 3000 m / min or less, yarn breakage during spinning can be suppressed and productivity can be increased.

  In the case of winding once after take-up, it is necessary to use a non-hydrous oil agent, which is not common as an oil agent used for polyester fibers for clothing, as the above-described spinning oil agent. Normally, the production of polyester fiber for clothing uses a water-containing oil agent in which the oil component is emulsified in water, but a non-water-containing oil agent uses an organic solvent as a diluent component for diluting the oil component. It is. The water content in the non-hydrous oil is preferably 5% by weight or less, more preferably 3% by weight or less. As a result of intensive studies, the present inventors have determined that even if the fiber structure is not sufficiently formed, the non-hydrous oil agent is used to rupture the yarn layer due to hygroscopic swelling during winding, It has been found that it is possible to suppress unwinding defects during stretching and uneven fineness in the longitudinal direction due to hygroscopic swelling of the drawn yarn package.

  On the other hand, in the case where stretching is performed continuously after take-up, a water-containing oil widely used as an oil for polyester fibers for clothing can be used as the above-described spinning oil. As a result of intensive studies, the inventors have formed a fiber structure by continuously stretching after take-up, and can suppress swelling due to moisture absorption in the oil after take-up. It was found that the yarn layer rupture and the fineness in the longitudinal direction can be suppressed.

  However, when the polymer alloy fiber of the present invention is left unstretched, it easily swells due to moisture absorption, and if there is a time difference until stretching, the fiber stretch properties and heat shrinkage characteristics easily vary between unstretched yarn packages. Or unsatisfactory unwinding during stretching. Therefore, it is preferable to employ a direct spinning / stretching method in which spinning and stretching are performed in one step.

  Stretching may be one stage or two or three stages, but it is preferable that stretching can be further enhanced by stretching two or three stages. The drawing temperature must be 30 ° C. or more and 140 ° C. or less, which is near the glass transition temperature of the undrawn yarn. Uniform stretching can be achieved by adjusting the temperature to 30 ° C. or higher, and deterioration of operability due to fusion to a stretching roll and spontaneous elongation of fibers can be prevented by setting the temperature to 140 ° C. or lower. The overall draw ratio obtained by multiplying the draw ratios at each stage is preferably set so that the obtained drawn yarn has an elongation of 25% or more and 100% or less, for example, 2.5 times or more and 5 times or less. preferable. By setting the elongation to 25% or more, generation of fuzz due to stretching can be suppressed and stretching operability can be improved. On the other hand, when the elongation is 100% or less, the strength can be increased, and the hygroscopic swelling during winding can be suppressed. Moreover, after drawing, it is preferable to heat-set at a temperature at which the crystal speed of the undrawn yarn is maximized, preferably 100 ° C. or higher and 220 ° C. or lower, more preferably 120 ° C. or higher and 200 ° C. or lower. By heat setting, fiber crystallization can be promoted, strength can be increased, and hygroscopic swelling can be suppressed. Moreover, it is preferable to arrange a plurality of rollers between the heat setting roll and the winder, and it is more preferable to provide relaxation here. By being relaxed, it is possible to suppress so-called winding tightening and physical property unevenness in which the paper tube does not come off the spindle due to self-shrinkage of the fiber after winding.

  By extending | stretching on said conditions, a fiber structure is formed and the hygroscopic swelling at the time of winding and storage can be suppressed. In addition, a drawn yarn having high process stability, high strength, and small fineness in the longitudinal direction can be obtained.

  The form of provision of the fiber of the present invention may be a fiber package in which the moisture-absorbing / releasing polyester fiber of the present invention is wound around a paper tube or a metal tube, or a fiber structure including at least a part of the fiber of the present invention. May be. The amount of fiber per fiber package is preferably 4 to 10 kg or more, and more preferably 6 to 10 kg or more. By setting it as 4 kg or more, the replacement period of the paper tube and the metal tube at the time of fiber manufacture can be reduced, and productivity improves. Moreover, the burden at the time of an operator carrying a fiber package can be reduced because it shall be 10 kg or less.

  The present invention will be specifically described below. The following measurement methods were used in the examples.

A. A weight average molecular weight sample of poly (N-vinyl lactam) was dissolved in dimethylformamide, and this was measured by gel permeation chromatography (GPC) (Waters 2690 manufactured by Waters). Poly (N-vinyl lactam) measured by a light scattering method was used as a standard at this time.

B. Using a differential scanning calorimeter with a melting point of polyester and fiber (DSC-7 manufactured by Perkin Elmer), a temperature at which an extreme value of a melting endothermic curve obtained by measuring 20 mg of a sample at a heating rate of 10 ° C./min is expressed as a melting point ( ° C).

C. U% (n) (longitudinal fineness spots)
Using a fineness unevenness measuring apparatus Zellweger (UT-4), U% (normal) was measured under the conditions of a yarn feeding speed of 200 m / min, a twister rotational speed of 12000 rpm, and a measurement length of 200 m.

D. Fiber strength, elongation at break, and toughness samples were measured with a tensile tester (Orientec “TENSILON UCT-100”) under the constant speed elongation conditions shown in JIS L1013 (1999) 8.5.1 standard time test. did. At this time, the holding interval was 20 cm, the pulling speed was 20 cm / min, and the number of tests was 10 times. The elongation at break was determined from the elongation at the point showing the maximum strength in the SS curve. Toughness was calculated from the following equation.
Toughness = strength (cN / dtex) × (elongation (%) ^0.5 ).

E. Cross section slices of single yarn cut perpendicularly to the length direction of the average dispersion diameter fiber of the moisture absorption polyester fiber is ruthenium-dyed, and the blend state is observed with a transmission electron microscope (TEM) (100,000 times)・ I took a picture. It has a sea-island structure in which a continuous matrix component (white portion) is a sea component, and a component (gray portion) dispersed in a substantially circular shape is an island component. The dispersion diameter of poly (N-vinylpyrrolidone) constituting the island component was converted to a diameter (assuming that the island component is a circle, and the diameter converted from the area of the island component). The average value of the individual island components was defined as the average dispersion diameter.

F. Hygroscopic ΔMR
Hygroscopicity uses 1 to 3 g of raw cotton or fabric, and is in an atmosphere of 20 ° C. × 65% RH or 30 ° C. × 90% RH in a constant temperature and humidity chamber (PR-2G manufactured by Tabai) From the change in weight with respect to the weight after standing for 24 hours, the following formula was obtained.
Moisture absorption rate (%) = (weight after moisture absorption−weight when absolutely dry) / weight when absolutely dry × 100
The moisture absorption difference ΔMR (%) = MR2−MR1 was determined from the moisture absorption rates (respectively MR1 and MR2) under the conditions of 20 ° C. × 65% RH and 30 ° C. × 90% RH.

G. Fiber color (L / b)
The fiber was wound on a metal plate at a winding tension of 0.2 g / dtex, measured twice using an SM color computer (SM-3 manufactured by Suga Test Instruments), and determined from the average value.

H. Using a wavelength dispersive X-ray fluorescence analyzer (Zigx made by Rigaku) for measuring the content of antimony atoms in polyester and fibers, element identification was performed using the diffraction angle at the peak position, and quantification was performed using the diffraction X-ray intensity. The attached semi-quantitative analysis software (SQX) was used for the analysis.

[Production Example 1] (Production of polybutylene terephthalate (titanium catalyst))
An esterification reaction and then a polycondensation reaction were performed using 1104 g of 1,4-butylene glycol and 1132 g of terephthalic acid. First, a total amount of terephthalic acid, 750 g of 1,4-butylene glycol, 0.88 g of titanium tetra-n-butoxide and 0.7 g of monobutylhydroxytin oxide were charged into a reactor equipped with a rectifying column, and conditions of 190 ° C. and 400 mmHg After starting the esterification reaction, the temperature was gradually raised and the remaining 1,4-butylene glycol was continuously added. Next, it was transferred to a polycondensation reaction can and subjected to a polycondensation reaction at a temperature of 250 ° C. for 4 hours under vacuum.

[Production Example 2] (Production of polybutylene terephthalate (antimony catalyst))
Instead of titanium tetra-n-butoxide as a reaction catalyst, it was the same as [Production Example 1] except that 0.45 g of general antimony trioxide was used as a polymerization catalyst for polyester.

[Production Example 3] (Production of copolymerized PET (titanium catalyst))
An esterification reaction and then a polycondensation reaction were performed using 784 g of ethylene glycol, 993 g of terephthalic acid, and 331 g of isophthalic acid. First, the total amount of terephthalic acid, the total amount of isophthalic acid, 533 g of ethylene glycol, 1.2 g of calcium acetate, and 0.88 g of titanium tetra-n-butoxide were charged into a reactor equipped with a rectifying column, and the temperature was increased from 130 ° C to 235 ° C in 3 hours. Warm, and after completion of the transesterification, add 0.57 g of methyl trimellitic acid. Next, it was transferred to a polycondensation reaction can and subjected to a polycondensation reaction at a temperature of 240 ° C. to 285 ° C. for 4 hours under vacuum.

[Production Example 4] (Production of copolymerized PET (antimony catalyst))
Instead of titanium tetra-n-butoxide as a reaction catalyst, it was the same as [Production Example 3] except that 0.45 g of general antimony trioxide was used as a polymerization catalyst for polyester.

[Production Example 5] (Production of polytrimethylene terephthalate (titanium catalyst))
An esterification reaction and then a polycondensation reaction were performed using 935 g of trimethylene glycol and 1209 g of terephthalic acid. First, a total amount of terephthalic acid, 653 g of ethylene glycol, and 0.88 g of titanium tetra-n-butoxide were charged into a reactor equipped with a rectifying column, and the temperature was raised from 130 ° C. to 210 ° C. over 3 hours. The product was transferred to a condensation reaction can, and a polycondensation reaction was carried out at 220 to 250 ° C. for 4 hours under vacuum.

[Production Example 6] (Production of PET (titanium-based catalyst))
Esterification reaction and then polycondensation reaction were carried out using 784 g of ethylene glycol and 1324 g of terephthalic acid. First, the total amount of terephthalic acid, 533 g of ethylene glycol, and 0.88 g of titanium tetra-n-butoxide were charged into a reactor equipped with a rectifying column, and the esterification reaction was started under conditions of 250 ° C. and 400 mmHg, and then gradually increased. While warming, the remaining butylene glycol was added continuously. Next, it was transferred to a polycondensation reaction can, and a polycondensation reaction was performed at a temperature of 285 ° C. under vacuum.

[Example 1]
Polybutylene terephthalate of [Production Example 1] and commercially available polyvinyl pyrrolidone K-30 (BASF, weight average molecular weight 50,000) were each hand blended at a ratio of 90:10, and a twin-screw extrusion kneader (in the same direction, biaxial) And kneading with a shaft diameter of 70 mm, L / D50). The polybutylene terephthalate was dried at 100 ° C. under vacuum for about 5 hours, and the moisture content was adjusted to 80 ppm. The twin screw extrusion kneader was kneaded at a jacket temperature of 240 ° C. and a shaft rotation speed at the time of kneading of 150 rpm, discharged from a die, water-cooled and pelletized. This chip was charged from a hopper into a single screw extruder (cylinder temperature 255 ° C.), weighed and discharged with a gear pump, the molten polymer was guided to a built-in spin pack (temperature 260 ° C.), and spun from a spinneret. A SUS nonwoven fabric filter (nonwoven fabric thickness: 0.6 mm) having an absolute filtration diameter of 10 μm was incorporated directly above the spin pack base. After spinning, the yarn was cooled and solidified with cooling air at a temperature of 20 ° C. and a speed of 0.4 m / sec, and an oil agent was applied by an oil supply device. A water-containing oil mixed in a ratio of polyether oil 15 and water 85 was attached to the spinning oil 7% to the yarn (1.0% owf as a pure oil).
Further, after taking up at a spinning speed of 1200 m / min with the first roll, the temperature of the second heating roll is taken at 1206 m / min with a temperature of 50 ° C., and further the drawing with a temperature of the third heating roll at 150 ° C. is drawn at 5050 m / min. (Drawing ratio: 4.19 times), and after cooling the yarn at a peripheral speed of 5050 m / min with a fourth roll, a winding tension of 5.6 g (0.1 cN / dtex), a winding speed of 5000 m / min. It was wound up in minutes (relaxation rate 1.0%). That is, the film was continuously stretched without being wound after spinning. The multifilament comprised from the obtained polymer alloy fiber was 56 dtex and 24 filaments.
When the TEM observation of the cross section of the obtained fiber was performed, it had a uniformly dispersed sea island structure, and the island component average dispersion diameter was 100 nm in terms of diameter. The fiber properties and color tone of the obtained fiber were good.

[Example 2]
A multifilament was obtained in the same manner as in Example 1 except that the ratio of polybutylene terephthalate and polyvinylpyrrolidone was 95: 5. The average dispersion diameter of island components in the cross section of the obtained fiber was 90 nm in terms of diameter. Although the obtained fiber was slightly inferior in moisture absorption / release properties, the physical properties and color tone were good.

[Example 3]
A multifilament was obtained in the same manner as in Example 1 except that the ratio of polybutylene terephthalate and polyvinylpyrrolidone was 80:20. The island component average dispersion diameter in the cross section of the obtained fiber was 120 nm in terms of diameter. The obtained fiber was particularly excellent in moisture absorption and desorption, and the physical properties and color tone were practically satisfactory, but the fineness in the longitudinal direction was slightly large.

[Example 4]
A multifilament was obtained in the same manner as in Example 1 except that a twin screw extruder kneader having a shaft diameter of 50 mm and L / D40 was used. The average dispersion diameter of island components in the cross section of the obtained fiber was slightly large at 400 nm in terms of diameter. The physical properties and color tone of the obtained fiber were practically acceptable, but the fineness in the longitudinal direction was slightly large.

[Example 5]
A multifilament was obtained in the same manner as in Example 1 except that the copolymerized PET of [Production Example 3] was used instead of polybutylene terephthalate, and the temperature of the second heating roll was 90 ° C. The average dispersion diameter of island components in the cross section of the obtained fiber was 100 nm in terms of diameter. The physical properties and color tone of the obtained fiber were good.

[Example 6]
A multifilament was obtained in the same manner as in Example 1 except that the polytrimethylene terephthalate of [Production Example 5] was used instead of polybutylene terephthalate. The average dispersion diameter of island components in the cross section of the obtained fiber was 100 nm in terms of diameter. The physical properties and color tone of the obtained fiber were good.

[Example 7]
As raw materials, polybutylene terephthalate of [Production Example 1], polybutylene terephthalate of [Production Example 2], and commercially available polyvinyl pyrrolidone K-30 (BASF, weight average molecular weight 50,000) are in a ratio of 45:55:10, respectively. A multifilament was obtained in the same manner as in Example 1 except that it was used in Example 1. The obtained fiber was gray, and although it looked somewhat inferior, it was practical.

[Example 8]
A multifilament was obtained in the same manner as in Example 1 except that polyvinylpyrrolidone K-17 (BASF Corp., weight average molecular weight: 9000) was used as poly (N-vinyl lactam). At the time of pelletizing after kneading, polyvinyl pyrrolidone was eluted in water, so that the moisture absorption / release property of the fiber obtained as compared with Example 1 was slightly lower, but it had sufficient moisture absorption / release property.

[Example 9]
A multifilament was obtained in the same manner as in Example 1 except that polyvinylpyrrolidone K-80 (BASF Corp., weight average molecular weight 850,000) was used as poly (N-vinyl lactam). Since the molecular weight of polyvinylpyrrolidone was high, the pressure in the spinning pack during melt spinning was slightly high, but it was at a level where there was no problem with the spinning performance. The island component average dispersion diameter in the cross section of the obtained fiber was slightly large at 330 nm in terms of diameter. The physical properties and color tone of the obtained fiber were practically acceptable, but the fineness in the longitudinal direction was slightly large.

[Example 10]
A multifilament was obtained in the same manner as in Example 1 except that polyvinylpyrrolidone K-85 (BASF Corporation, weight average molecular weight 1.1 million) was used as poly (N-vinyl lactam). Since the molecular weight of polyvinylpyrrolidone was high, the pressure in the spinning pack during melt spinning was slightly high, but it was at a level where there was no problem with the spinning performance. The average dispersion diameter of island components in the cross section of the obtained fiber was slightly large at 480 nm in terms of diameter. The physical properties and color tone of the obtained fiber were practically acceptable, but the fineness in the longitudinal direction was slightly large.

[Example 11]
A non-hydrous oil mixed at a ratio of polyether oil 15 and low-viscosity mineral oil 85 as a spinning oil was adhered to the yarn by 7% (1.0% owf as a pure oil), and then spun by the first roll. After taking up at a speed of 1200 m / min, it was wound up once. Five days later, after confirming that the yarn layer was not hygroscopically swollen, it was stretched at a stretching temperature of 50 ° C., a heat setting temperature of 150 ° C., and a stretching speed of 800 m / min (stretching ratio: 4.19 times). )did. Other than this, a multifilament was obtained in the same manner as in Example 1. The physical properties and color tone of the obtained fiber were good.

[Comparative Example 1]
A multifilament was obtained in the same manner as in Example 1 except that polyvinylpyrrolidone was not used. Although the obtained fiber was very good, it had no moisture absorption / release property.

[Comparative Example 2]
A multifilament was obtained in the same manner as in Example 1 except that the ratio of polybutylene terephthalate to polyvinylpyrrolidone was set to 70:30. The island component average dispersion diameter in the cross section of the obtained fiber was 150 nm in terms of diameter. Although the moisture absorption and desorption of the obtained fiber was very high, the strength and toughness were low, and the fineness unevenness in the longitudinal direction was high, so that the process passability was poor and the durability as a garment was a problem in practice. It was.

[Comparative Example 3]
A multifilament was obtained in the same manner as in Example 1 except that a biaxial extrusion kneader having a shaft diameter of 30 mm and L / D30 was used. The average dispersion diameter of island components in the cross section of the obtained fiber was as large as 600 nm in terms of diameter. The obtained fiber had very large fineness spots in the longitudinal direction, so that the fiber properties were slightly inferior and the process passability was poor.

[Comparative Example 4]
Spinning was carried out in the same manner as in Example 1 except that the polymer of [Production Example 2] was used as polybutylene terephthalate. Since the spun polymer was colored black, an irritating odor such as acid was generated during spinning, and there was a lot of fuming, so fibers could not be obtained.

[Comparative Example 5]
Spinning was performed in the same manner as in Example 5 except that the polymer of [Production Example 4] was used as copolymerized PET. Since the spun polymer was colored black, an irritating odor such as acid was generated during spinning, and there was a lot of fuming, so fibers could not be obtained.

[Comparative Example 6]
Implemented except that the polyethylene terephthalate of [Production Example 6] was used instead of polybutylene terephthalate, and the jacket temperature and the spinning pack temperature of the twin screw extruder and the single screw extruder were set to 295 ° C. and the second heating roll temperature was set to 90 ° C. A multifilament was obtained in the same manner as in Example 1. Although a slightly burning odor and smoke were observed during spinning, fibers could be obtained. Although the obtained fiber had practical physical properties, yellow coloring was observed, and it was not practical.

[Comparative Example 7]
A multifilament was obtained in the same manner as in Example 6 except that the hydrous oil of Example 1 was used as the spinning oil. Within a few minutes after the start of winding, the yarn layer ruptured due to the hygroscopic swelling of the fiber occurred, and the fiber could not be wound for a long time. Even during stretching, unraveling defects that appear to be due to hygroscopic swelling of the fibers occurred, and the fineness unevenness in the longitudinal direction that seems to be due to swelling and unraveling defects became very large.

[Comparative Example 8]
Winding was performed in the same manner as in Example 6 except that the water-containing oil of Example 1 was used as the spinning oil, and the spinning speed at the first roll was 3500 m / min, and partially oriented multifilaments were obtained without stretching. Within a few minutes after the start of winding, the yarn layer ruptured due to the hygroscopic swelling of the fiber occurred, and the fiber could not be wound for a long time. Even during stretching, unraveling defects that appear to be due to hygroscopic swelling of the fibers occurred, and the fineness unevenness in the longitudinal direction that seems to be due to swelling and unraveling defects became very large.

Claims (6)

  In the fiber, poly (N-vinyllactam) is 3 to 25% by weight, the dispersion diameter in the fiber cross section is finely dispersed at 500 nm or less, the hygroscopic parameter (ΔMR) is 1.0% or more, and the strength is 2 A moisture-absorbing / releasing polyester fiber characterized by 0.0 cN / dtex or more, toughness of 15 or more, fineness unevenness U% (n) of 1.5 or less, color tone L value of 70 or more, and b value of 10 or less.   The hygroscopic polyester fiber according to claim 1, wherein the poly (N-vinyl lactam) is polyvinyl pyrrolidone.   The hygroscopic polyester fiber according to claim 1 or 2, wherein the antimony atom content in the fiber is 50 ppm or less.   The moisture-absorbing / releasing polyester fiber according to any one of claims 1 to 3, wherein the melting point is 255 ° C or lower.   Poly (N-vinyl lactam) is added to a polyester having a melting point of 255 ° C. or less and an antimony atom content of 50 ppm or less, so that the weight ratio is 97: 3 to 75:25 and the dispersion diameter in the fiber cross section is 500 nm or less. Melt and knead at 270 ° C. and once cooled and then chipped, or continuously fed into the spinning apparatus in a molten state, weighed, passed through a filter made of a metal nonwoven fabric placed on the base, After cooling and refueling the fiber discharged from the pipe, it is taken up at 300 m / min or more, continuously led to a drawing process, and drawn in one or two stages at a drawing temperature of 30 to 140 ° C. The manufacturing method of the moisture absorption / release polyester fiber of any one of Claims 1-4.   Poly (N-vinyl lactam) is added to a polyester having a melting point of 255 ° C. or less and an antimony atom content of 50 ppm or less, so that the weight ratio is 97: 3 to 75:25 and the dispersion diameter in the fiber cross section is 500 nm or less. Melt and knead at 270 ° C. and once cooled and then chipped, or continuously fed into the spinning apparatus in a molten state, weighed, passed through a filter made of a metal nonwoven fabric placed on the base, After cooling the fiber discharged from and supplying a non-hydrous oil agent, it is taken up at 300 m / min or more, wound up once, and drawn up in one or two stages at a drawing temperature of 30 to 140 ° C. The manufacturing method of the moisture absorption / release polyester fiber of any one of Claims 1-4.