JP6443127B2 - Method for producing hygroscopic polyester fiber - Google Patents

Description

  The present invention relates to a method for producing a polyester fiber having good moisture absorption / release properties.

  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, they are used when touching the skin directly, such as inner, inner garments, and sports clothing, or when used in a field worn near the skin. , Which 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 release properties, so the advance 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 only describes a general production method, and in the examples, only a film is produced. When the fibers were produced according to the literature, the fibers were colored black, the smoke during operation and the yellowness of the fibers were increased, the spinning operability was poor, the yarn breakage occurred frequently, and the fineness in the longitudinal direction of the fibers was large. Many problems occurred, such as the yarn layer ruptured during take-up, swelling during storage of the take-up yarn, and the unwindability during drawing worsened, resulting in poor drawability and large fineness spots.

  As described above, studies on moisture-absorbing and releasing fibers are being studied as shown in the above-mentioned patent documents, and technical advances have been made. However, little research has been conducted on a method for producing moisture-absorbing / releasing fibers with good yarn production and moisture-absorbing / releasing performance, and a method for producing moisture-absorbing / releasing fibers satisfying moisture-releasing and spinning properties is awaited. It was.

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

  An object of the present invention is to provide a method for producing a moisture-absorbing / releasing polyester fiber having excellent fiber properties and having a good moisture-absorbing / releasing property and yarn forming property.

  The above problem is that a master chip is prepared by melt-kneading poly (N-vinyl lactam) with polyester A having a melting point of 255 ° C. or less and an antimony atom content of 50 ppm or less. Can be solved by a method for producing a moisture-absorbing / releasing polyester fiber, characterized in that blending is carried out at a weight ratio of 1: 0.5 to 1:10, followed by melt spinning.

  According to the present invention, moisture-absorbing / releasing polyester fibers having excellent fiber properties that could not be achieved by the prior art, good yarn-making properties, and sufficient moisture-absorbing / releasing properties to obtain wearing comfort. This can be achieved by the manufacturing method.

  The moisture-absorbing / releasing polyester fiber obtained by the production method of the present invention is a fiber made of 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.

The outline of the manufacturing method of the moisture absorption / release polyester fiber of this invention is shown below.
A polyester A 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 used in a kneading apparatus of a twin screw extruder having a screw diameter of 40 mm to 130 mm and L / D 35 to 80. A weight ratio of 97: 3 to 55:45 is prepared by melt-kneading so that an average dispersion diameter in the fiber cross section is 500 nm or less to prepare a master polymer, which is once cooled and chipped or continuously in a molten state. And feed it into the spinning device.

  The metallic nonwoven fabric placed on the die after blending and weighing the master polymer and base polymer B fed to the spinning device at a low temperature and low shear rate so that the weight ratio is 1: 0.5 to 1:10 After the fiber discharged from the base is cooled and supplied with oil, it is taken up at 300 m / min or more and continuously led to a drawing process. One or two steps at a drawing temperature of 30 ° C. or more and 140 ° C. or less The film is stretched and wound up.

Next, details of each manufacturing process will be described.
The polyester A used in the production method of the present invention will be described. First, the melting point of the polyester A needs to be 255 ° C. or lower, and is preferably 245 ° C. or lower. This is because poly (N-vinyl lactam) used as a moisture absorbing / releasing component turns yellow due to thermal degradation at high temperatures, lowers the performance of moisture absorbing / releasing fibers, causes poor yarn-making properties, and deteriorates the color tone b value. Cause. For this reason, the kneading temperature and the spinning temperature can be kept low by using a polyester having a melting point of 255 ° C. or less, the thermal deterioration of poly (N-vinyl lactam) can be suppressed, and the performance of the moisture absorbing / releasing fiber is lowered. In other words, a fiber that has good spinning properties and can suppress deterioration of the color tone b value can be obtained.

  The polyester A used for the base polymer melt-kneaded with the hygroscopic polymer needs to have an antimony atom content of 50 ppm or less, and preferably 40 ppm or less. As a catalyst used in the polycondensation of polyester, antimony trioxide is widely used. In this case, the content of antimony atoms in the polyester is 100 ppm or more, but the polyester A used in the present invention has an antimony atom content. In this case, the antimony atom content of the hygroscopic polyester fiber is also 50 ppm or less. As described above, there has been a problem that the master polymer is colored black by kneading polyester A and poly (N-vinyl lactam). Ascertaining that it is due to the reaction between antimony atoms and poly (N-vinyl lactam), and using polyester with an antimony atom content of 50 ppm or less, the master 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. In order to reduce the content of antimony atoms in the polyester to 50 ppm or less, it can be achieved 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. .

  On the other hand, the polyester B blended with the master polymer at the time of spinning preferably has an antimony atom content of 200 ppm or more. It is known that a catalyst other than the antimony catalyst such as a titanium catalyst acts to color by reacting with the polyester, and coloring by a catalyst other than the antimony catalyst can be suppressed by setting the antimony atom content to 200 ppm or more.

  As the polyester used in the production method of the present invention, either an aromatic polyester or an 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. By copolymerizing these asymmetric molecules in the polymer, the melting point of the copolyester can be lowered. In particular, isophthalic acid is preferable because it has a molecular structure close to that of terephthalic acid and does not impair the physical properties of the composition. 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.

  As the moisture absorbing / releasing component poly (N-vinyl lactam) used in the master polymer of the present invention, N-vinyl lactams such as N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, and N-vinyl caprolactam can be used. A polymer. 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. The polyvinyl pyrrolidone generally has a weight average molecular weight of 50,000 to 2,500,000, among which a weight average molecular weight of 10,000 to 1,000,000 is preferable, 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 master polymer is increased, and it is possible to suppress the aggregation in the polyester to lower the dispersibility and the increase in the polymer pressure applied to the apparatus during spinning.

  The master polymer used for the moisture-absorbing / releasing fibers is made up of 100 parts by weight of the total amount of polyester A and poly (N-vinyl lactam), 55 to 97 parts by weight of polyester A, 45 to 3 parts by weight of poly (N-vinyl lactam). Are weighed and kneaded. 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 content 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.

  Moisture absorption and desorption can be expressed by setting poly (N-vinyl lactam) to 3 parts by weight or more. On the other hand, it can knead | mix stably by making poly (N-vinyl lactam) into 45 weight part or less. It is preferable that poly (N-vinyl lactam) is 10 parts by weight or more and 45 parts by weight or less.

  A device used in the kneading step in the production of the master polymer is preferably a twin screw extruder having a screw diameter of 40 mm to 130 mm and an L / D of 35 to 80. Productivity can be increased by setting the screw diameter to 40 mm or more, and kneadability can be increased by setting the screw diameter to 130 mm or less. When L / D is 35 or more, fine dispersion can be achieved, and when L / D is 80 or less, thermal history can be suppressed. The moisture absorption / release polyester fiber of the present invention has an average dispersion diameter of island components in the fiber cross section of 500 nm or less, and any other twin screw extruder may be used as long as it is a kneading apparatus capable of achieving this. But you can. On the other hand, it is difficult to make the average dispersion diameter of the island component 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.

  Generally, the kneading temperature is Tm + 10 ° C. to Tm + 50 ° C. on the basis of the melting point of polyester (hereinafter referred to as Tm). Poly (N-vinyl lactam) used in the present invention is thermally deteriorated or yellowed at high temperatures. Since it may be colored or smoked, it is preferably kneaded at a temperature lower than normal Tm + 5 ° C. or higher and Tm + 25 ° C. or lower. If it is Tm + 5 ° C. or higher, it is a melting temperature sufficient for kneading, and if it is Tm + 25 ° C. or lower, it does not cause thermal deterioration, yellowing, or smoke generation, which is preferable.

  The moisture-absorbing / releasing polyester fiber obtained by the production method of the present invention is produced by blend spinning the master polymer and polyester B. It is necessary to make the master polymer and polyester B have a weight ratio of 1: 0.5 to 1:10. As a result, a fiber having good moisture absorption and desorption and b value can be obtained.

  Polyester B can impart various properties to the fiber obtained by being a polymer different from polyester A. Here, different means that the polymer itself (copolymerization component, copolymerization amount, etc.) is different, and excludes the case where the added particles, etc. (titanium oxide, light-proofing agent, etc.) and only their amounts are different. Moreover, it is preferable that the antimony atomic weight contained in the polyester B is 200 ppm or more and 400 ppm or less. By setting the antimony atomic weight to 200 ppm or more, deterioration of the b value can be suppressed, and by setting it to 400 ppm or less, a decrease in the L value of the fiber can be suppressed.

  The shear rate at the time of blending is such that poly (N-vinyllactam) and antimony react and color black under high shear, so it is important to set a low shear rate, and the shear rate is 10 (1 / sec. ) To 500 (1 / sec), preferably 400 (1 / sec) or less. By setting the shear rate to 10 (1 / sec) or more, kneading can be efficiently performed without increasing the kneading time, and by setting the shear rate to 500 (1 / sec) or less, poly (N -Vinyllactam) and antimony do not react and are not colored black, which is preferable. This is because the poly (N-vinyl lactam) in the master polymer is a polymer alloy with the polyester A, so even if the antimony is contained in the polyester B, the poly (N-vinyl lactam) is in the shear rate range. This is because there are few opportunities for contact with antimony. As long as the blending apparatus can achieve the shear rate, a twin-screw extruder or a single-screw extruder may be used. However, the most preferable blending apparatus that does not change the color of the polymer to black and the average dispersion diameter of the island components is 500 nm or less. It is a high mixer.

The high mixer used in the present invention will be briefly described. The high mixer is effective for dividing and mixing the polymer. For example, when the fluid to be blended is fed into the high mixer according to the blend ratio, it is divided into four equal parts and flows into the passage pipe. By the action of the twisted blades in the passage pipe, the respective fluids flow while moving, and merge again in the intermediate chamber. The two types of fluid divided into two phases at the entrance are divided into eight phases by passing through one element. Then, it the number of divided layers N, the number of elements n, when the first inlet layer speed No and N = No × ^{4 n.} By the way, in the case of a five-stage high mixer, 2 × 4 ⁵ = 2048 divisions.

  In the present invention, when a 5- to 12-stage high mixer is used, a black polymer is not generated, and a good moisture absorption / release property, uniform yarn physical properties are obtained, and a moisture absorption / release fiber having a good yarn production property is obtained. This is preferable. A high mixer having five or more stages can provide a highly uniform alloy phase structure and a blending effect that can sufficiently reduce the domain size of island components. If it is 12 stages or less, the shear heat generation is small, the black polymer is not generated, and the hygroscopic polymer can be finely dispersed, and the apparatus can be incorporated in the pipe or pack without being excessively large. It is also preferable from the viewpoint. More preferably, it is 6 to 10 stages, and most preferably 7 to 8 stages.

  The high mixer can be installed in a polymer pipe or in a pack, or a combination of both. However, black polymer is not generated, and good moisture absorption and uniform yarn properties are obtained. If it is possible to obtain moisture-absorbing / releasing fibers that have good yarn-making properties, it is not necessary to specify the position of incorporation.

  The jacket temperature during melt spinning is preferably Tm + 5 to Tm + 40 ° C. based on the melting point of polyester (hereinafter referred to as Tm). 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 is thermally deteriorated at a high temperature, and is colored yellow or emits smoke. It is more preferable that it is Tm + 5-Tm + 25 degreeC.

  Moreover, in order to control the island component dispersion diameter by suppressing the reaggregation of the island domains in the spinning pack, a high mesh filter layer (# 100 to # 200) or a non-woven filter with a small filtration diameter (filtration diameter 5 to 5). 30 μm) may be arranged on the base. Among them, a multilayer filter made of a metal nonwoven fabric having a plurality of wire diameters is most effective for controlling the island component dispersion diameter.

  The moisture-absorbing and releasing polyester fiber obtained by the production method of the present invention needs to be a polymer alloy fiber having a sea-island structure in which polyester is sea and poly (N-vinyl lactam) is island. By using polyester as a sea component, the polyester can bear high mechanical properties, and as a result, a sea-island composite structure fiber having high mechanical properties can be obtained. 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 discharged filament may be a monofilament or a multifilament. As the shape of the nozzle 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 can be selected according to the application. Here, if it is other than a round cross section, the specific surface area of the fiber is increased, so that the moisture absorption / release rate is increased, which is preferable.

  The cooling method 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 from the inside to the outside of the yarn. An annular chimney to be cooled is preferable in that it can be uniformly cooled. At this time, it is desirable to cool the multifilament by applying a gas from a direction orthogonal to the multifilament. The speed of the cooling air at this time is preferably 0.2 to 1 m / sec, and more preferably 0.3 to 0.8 m / sec. Further, the temperature of the cooling air is preferably low for uniform cooling, but it is practically preferable to be 15 to 25 ° C. in consideration of the temperature adjustment cost of the cooling air.

  The spun multifilament is coated with a known spinning oil, and the amount of adhesion at this time is 0.3 to 3% by weight as pure oil with respect to the yarn. The spinning oil may be a water-containing oil widely used as a polyester fiber for clothing or a non-water-containing oil.

  The spinning speed is taken up at a speed of 300 m / min or more, and it is wound up once or continuously drawn. Productivity can be improved by winding up at 300 m / min or more. A preferred spinning speed is 500 to 3000 m / min. By spinning at 3000 m / min or less, yarn breakage during spinning can be suppressed and productivity can be increased.

  Stretching may be one stage or two or three stages, but it is preferable to stretch two or three stages since the strength can be further increased. The drawing temperature must be 30 to 140 ° C., 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 total 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 to 100%, for example, 2.5 to 5 times. By setting the elongation to 25% or more, it is possible to suppress the generation of fluff due to stretching and improve the stretching operability, and by setting the elongation to 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 crystallization speed of the undrawn yarn is maximized, preferably 100 to 220 ° C, more preferably 120 to 200 ° C. 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 doing so, it is possible to suppress winding tightness and physical property spots that prevent the paper tube from coming out of the spindle due to 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.

  As a form of providing the fiber obtained by the production method of the present invention, 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 may be used, or at least a part of the fiber of the present invention may be used. The fiber structure containing may be sufficient. 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 characteristics of the moisture absorbing / releasing polyester fiber obtained by the production method of the present invention will be described. The dispersion diameter of the island component in the fiber cross section is 500 nm or less, preferably 10 to 300 nm or less, more preferably 20 to 150 nm. By setting the dispersion diameter to 500 nm or less, the specific interface area of the sea-island interface can be made sufficiently large, cracking of the sea component due to volume change due to moisture absorption and swelling of the island component can be suppressed, The moisture rate becomes high, and the moisture absorption and desorption properties are 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 island component dispersion diameter is large, the island component stretched during discharge of the die also has a greater force to return to a spherical shape due to the interfacial tension between the polymers after discharge, which is several times the discharge hole diameter just below the discharge hole, called the ballast effect. A bulge having a diameter is generated. For this reason, thinning is likely to occur in the process of thinning deformation during spinning, which causes problems in quality such as fineness in the longitudinal direction, and thread breakage occurs when the thickness is large. Further, by setting the dispersion diameter to 10 nm or more, it is possible to suppress shear applied to the polymer during kneading, and it is possible to suppress deterioration in physical properties and color tone due to molecular chain cleavage.

  The moisture absorbing / releasing parameter ΔMR of the moisture absorbing / releasing polyester fiber obtained by the production method of the present invention 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.

  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 toughness 17 or more. 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. In order to increase the fiber strength, it is common to increase the draw ratio at the time of manufacture, but this increases the strength but decreases the elongation, tends to cause fluffing, and passes through processes such as weaving. Becomes worse. For this reason, to obtain high strength while maintaining sufficient elongation, the toughness needs to be 15 or more, preferably 18 or more, and more preferably 20 or more.

  The fineness unevenness U% (n) in the longitudinal direction of the hygroscopic polyester fiber obtained by the production method of the present invention needs to be 1.5% or less, preferably 1.0% or less. More preferably, it is 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 present invention will be specifically described below. The following measurement methods were used in the examples.

A. Weight average molecular weight of poly (N-vinyl lactam) A sample 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. Melting point of polyester and fiber Using a differential scanning calorimeter (DSC-7 manufactured by Perkin Elmer), a temperature giving 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 a melting point ( ° C).

C. Polymer viscosity (intrinsic viscosity)
Measurement was performed at a temperature of 25 ° C. using orthochlorophenol as a solvent.

D. 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.

E. Fiber strength, elongation at break and toughness Samples were measured with a tensile tester ("TENSILON UCT-100" manufactured by Orientec) 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).

F. Average dispersion diameter of island component of moisture-absorbing polyester fiber Ruthenium-dyed cross section slice of single yarn cut perpendicular to the length direction of fiber and observed blend state with 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.

G. 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.

H. 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.

I. Measurement of antimony atom content in polyester and fiber Using a wavelength dispersive X-ray fluorescence analyzer (ZSX, manufactured by Rigaku), element identification and diffraction X-ray intensity were quantified at the diffraction angle at the peak position. The attached semi-quantitative analysis software (SQX) was used for the analysis.

J. et al. Various polyester raw materials The raw material polyesters in Table 1 used in the examples were produced by conventional methods.

  The method for producing the raw material polyester is exemplified below.

[Production Example 1] <PET / IF>
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. After completion of the transesterification reaction, the mixture 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 2] <PET / I-J>
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] <Homo PET-A>
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.

[Production Example 4] <Homo PET-E>
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] <PET / II>
Instead of titanium tetra-n-butoxide as a reaction catalyst, it was the same as [Production Example 1] except that 0.11 g of general antimony trioxide was used as a polyester polymerization catalyst.
[Production Example 6] <Homo PET-B>
Instead of titanium tetra-n-butoxide as a reaction catalyst, it was the same as [Production Example 3] except that 0.11 g of general antimony trioxide was used as a polyester polymerization catalyst.

[Example 1]
PET / IF and commercially available polyvinyl pyrrolidone K-30 (BASF, weight average molecular weight 50,000) are hand blended at a ratio of 70:30, respectively, and a twin screw extrusion kneader (same direction biaxial, shaft diameter 70 mm). , L / D50). The copolymerized PET was dried at 150 ° C. under vacuum for about 5 hours, and the moisture content was adjusted to 80 ppm. Kneading was performed at a jacket temperature of a twin screw extrusion kneader at 240 ° C. and a shaft rotational speed at the time of kneading at 150 rpm. After discharging from the die, water cooling and pelletizing were performed to prepare a master polymer.

  The master polymer and homo-PET-E were charged from a separate hopper at a ratio of 2 with respect to the master polymer 1, and a single screw extruder (cylinder temperature = master polymer: 240 ° C., PET: 295 ° C.), Furthermore, it is measured and discharged by a gear pump, the molten polymer is guided to a built-in spinning pack (temperature: 275 ° C.), and the master polymer and homo-PET-E are blended by 8 stages of high mixers built in the spinning pack, and spinning is performed. Spinned from the base. 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 composed of the obtained fibers was 56 dtex and 24 filaments.

  During spinning for 72 hours, there was no yarn breakage and good spinning performance. 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. Moreover, the moisture absorption / release property, fiber physical 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 copolymerized PET / IK was used as polyester A. The resulting fibers had good moisture absorption / release properties, fiber properties, and color tone.

[Example 3]
A multifilament was obtained in the same manner as in Example 1 except that copolymerized PET / IL was used as polyester A. Although the b value of the obtained fiber was slightly high, the moisture absorption / release property, the fiber physical property and the color tone were good.

[Example 4]
A multifilament was obtained in the same manner as in Example 1 except that copolymerized PET / IG was used as polyester A. The resulting fibers had good moisture absorption / release properties, fiber properties, and color tone.

[Example 5]
A multifilament was obtained in the same manner as in Example 1 except that copolymerized PET / I-H was used as polyester A. Although the L value of the obtained fiber was slightly low, the moisture absorption / release property, fiber physical properties and color tone were good.

[Example 6]
A multifilament was obtained in the same manner as in Example 1 except that polytrimethylene terephthalate of homo PTT-M was used as polyester A. The resulting fibers had good moisture absorption / release properties, fiber properties, and color tone.

[Example 7]
A multifilament was obtained in the same manner as in Example 1 except that polybutylene terephthalate of homo PBT-N was used as polyester A. The resulting fibers had good moisture absorption / release properties, fiber properties, and color tone.

[Example 8]
A multifilament was obtained in the same manner as in Example 1 except that K-17 (BASF Corp., weight average molecular weight 9000) was used as polyvinylpyrrolidone. The resulting fibers had good moisture absorption / release properties, fiber properties, and color tone.

[Example 9]
A multifilament was obtained in the same manner as in Example 1 except that K-80 (BASF, weight average molecular weight 850,000) was used as polyvinylpyrrolidone. The resulting fibers had good moisture absorption / release properties, fiber properties, and color tone.

[Example 10]
A multifilament was obtained in the same manner as in Example 1 except that homo-PET-D was used as polyester B. The resulting fibers had good moisture absorption / release properties, fiber properties, and color tone.

[Example 11]
A multifilament was obtained in the same manner as in Example 1 except that homo-PET-C was used as polyester B. The b value of the obtained fiber was slightly high, but the moisture absorption / release property, fiber physical properties and color tone were good.

[Example 12]
A multifilament was obtained in the same manner as in Example 1 except that copolymer PET / I-J was used instead of homo PET-E as the base polymer blended with the master polymer. The resulting fibers had good moisture absorption / release properties, fiber properties, and color tone.

[Examples 13 to 16]
In place of the high mixer 8 stage of [Example 1], 5 stages of high mixers are incorporated in the pack (Example 13), 4 stages in the polymer passage + 8 stages in the pack, total 12 stages of high mixer (Example 14), A multifilament was obtained in the same manner as in Example 1 except that a single-screw extruder (Example 15) and a twin-screw extruder (Example 16) were installed in the polymer passage instead of the high mixer.

  In Example 13, the fineness in the longitudinal direction was slightly increased, and in Examples 14 to 16, the L value was slightly low and the b value was high.

[Example 17]
A multifilament was obtained in the same manner as in Example 1 except that the blend ratio of the master polymer and polyester B during spinning in Example 1 was 1: 0.5.

  The obtained fiber was slightly yellowish, and although the fineness in the longitudinal direction was slightly large, there was no problem in practical use.

[Example 18]
Example 1 except that the kneading ratio of polyester A of Example 1 and polyvinylpyrrolidone K-30 (BASF) was 85:15, and the blending ratio during spinning was master polymer: polyester B = 1: 0.5. In the same manner, a multifilament was obtained.
Although the obtained fiber was slightly yellowish, there was no problem in practical use.

[Example 19]
Example 1 except that the kneading ratio of polyester A of Example 1 and polyvinylpyrrolidone K-30 (BASF) was 55:45 and the blending ratio during spinning was master polymer: polyester B = 1: 10. A multifilament was obtained.

  Although the moisture absorption / release property was slightly low, it was at an acceptable level, and the fiber properties were not particularly problematic.

[Example 20]
In Example 1, a twin screw extruder was used for the melting part of the spinning machine, and PET / IF and polyvinylpyrrolidone K-30 were kneaded here, and the master polymer was continuously spun in the molten state. To obtain a multifilament. The obtained fiber had good physical properties.

[Example 21]
A multifilament was obtained in the same manner as in Example 1 except that the number of high mixers blended in the pack was changed to three. Although the moisture absorption / release properties, fiber properties, and color tone of the obtained fiber were not particularly problematic, the fineness unevenness in the longitudinal direction was slightly increased due to insufficient blending.

[Example 22]
A multifilament was obtained in the same manner as in Example 1 except that a high-shear twin screw extruder was used during melting in the spinning process, and a normal pack not incorporating a high mixer was used. Although it became a slightly gray fiber, there was no particular problem with the moisture absorption / release properties and fiber properties of the obtained fiber.

[Example 23]
A multifilament was obtained in the same manner as in Example 1 except that homo-PET-A was used instead of homo-PET-E as the base polymer blended with the master polymer.

  The antimony of the obtained fiber was lower than that of Example 1, and although the hygroscopicity was good, the fiber became slightly strong yellowish.

[Comparative Example 1]
When copolymer PET / I-I is used as polyester A and homo-PET-B is used as polyester B, an irritating odor such as acid is generated during the preparation of the master polymer and during spinning, and there is a lot of fuming, and the master polymer is colored black. It was observed. Further, although the antimony atom content in the fiber was as low as 100 ppm, the fiber was also colored black.

[Comparative Example 2]
As polyester A, spinning was carried out in the same manner as in Example 1 except that homo-PET-A was used.

  A multifilament was obtained in the same manner as in Example 1, except that the jacket temperature and spin pack temperature of the extruder were 295 ° C., and the second heating roll temperature was 90 ° C. Although a burning odor and smoke were observed during spinning, fibers could be obtained. The obtained fiber was inferior in moisture absorption and desorption, and the color tone was yellowish, which was not practical.

[Comparative Examples 3 and 4]
A multifilament was obtained in the same manner as in Example 1 except that the ratio of polyester B blended with the master polymer in the spinning process was changed to 1: 0.3 (Comparative Example 3) and 1:15 (Comparative Example 4).

  In Comparative Example 3, although the moisture absorption / release property of the obtained fiber was high, the strength and toughness were low, and the fineness unevenness in the longitudinal direction was high, so the process passability was poor, and the durability as a garment was also a problem in practice. It was a thing. In Comparative Example 4, the yarn physical properties were good, but the moisture absorption / release properties were inferior.

  The moisture-absorbing / releasing polyester fiber obtained by the production method 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, and 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, it can be effectively used in fields where the skin is directly touched or worn in a state close to the skin, such as an inner, a middle garment, and sports clothing.

Claims (6)

  A master polymer is prepared by melt-kneading poly (N-vinyl lactam) with polyester A having a melting point of 255 ° C. or less and an antimony atom content of 50 ppm or less, and then the weight ratio of the master polymer and polyester B is 1 in a spinning device. : A method for producing moisture-absorbing and releasing polyester fibers, characterized by blending so as to be 0.5 to 1:10 and then melt spinning.   The method for producing hygroscopic polyester fibers according to claim 1, wherein the base polymer polyester B is a polyester different from the master polymer polyester A.   3. The method for producing moisture-absorbing and releasing polyester fibers according to claim 1, wherein the antimony atom content of the base polymer polyester B is 200 ppm or more. The method for producing moisture-absorbing and releasing polyester fibers according to any one of claims 1 to 3, wherein the master polymer is once cooled to form a chip after producing the master polymer. The method for producing hygroscopic polyester fibers according to any one of claims 1 to 3, wherein the master polymer is continuously fed to the spinning device in a molten state.   The method for producing moisture-absorbing / releasing polyester fibers according to any one of claims 1 to 5, wherein the blend of the master polymer and the base polymer polyester B is performed at a shear rate of 10 to 500 (1 / sec).