JP2005048297A - Polyurethane elastic fiber having improved moisture absorbing and releasing property and fabric using the same fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane elastic fiber quickly removing water vapor emitted by perspiration during exercise, suitable for stretchable clothes without causing sweatiness and having excellent heat resistance and post-processing passableness and to provide a woven or a knitted fabric using the polyurethane elastic fiber. <P>SOLUTION: The polyurethane elastic fiber comprises a highly moisture absorbing and releasing organic substance insoluble in dimethylacetamide and has ≥4.5 wt.% coefficient of moisture absorption at 20°C and 65%RH, ≥0.110 m<SP>2</SP>/g fiber surface area, ≥450% elongation at break and improved moisture absorbing and releasing properties. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyurethane elastic fiber having excellent hygroscopicity, heat resistance and good post-processing passability, and a woven or knitted fabric using the same.
[0002]
[Prior art]
Unlike natural fibers such as cotton, wool, and silk, synthetic fibers such as polyester fibers, nylon fibers, and polyurethane elastic fibers are generally poor in hygroscopicity because of their low hydrophilic functional group content. Therefore, synthetic fiber hydrophilization technology has been studied for many years, and various hydrophilic processing has been proposed (for example, see Non-Patent Document 1).
[0003]
A technique for improving the water absorption of polyurethane-based elastic fibers is known (for example, refer to Patent Document 1), which has a combination of high water absorption, high biocompatibility, and excellent physical strength, and has good processability. Insoluble, non-ionic water-absorbing polyurethane yarns and melt spinning methods are disclosed. However, since the water absorption rate is 200% or more and the fiber-constituting polymer itself has high water absorption performance, the fiber surface swells during washing or sweat water absorption and gives a feeling of nulliness, so it can be used for clothing. Problems arise.
[0004]
Moreover, the technique which improves the hygroscopic property of a polyurethane-type elastic fiber by using the water-soluble polyalkylene ether polyol which is a hydrophilic polyol for the polyol component of a polymer is disclosed (for example, refer patent document 2). According to this, it has been disclosed that the above-mentioned problems are solved and the influence of swelling can be reduced to a level that does not affect the texture even when used for clothing, but the following problems remain.
[0005]
In the method of mixing a highly water-absorbing polymer with the technology for enhancing the moisture permeability of polyurethane-based elastic fibers, examples of the highly water-absorbing polymer include polyacrylic acid-based polymers, polyvinyl-based polymers, polyamide-based polymers, and highly water-absorbing polyurethanes. There are polymers and the like, but these superabsorbent polymers are localized, which causes problems such as deterioration of physical properties and impaired spinning stability. Furthermore, since the superabsorbent polymer is generally not cross-linked, it swells due to water absorption and causes the polyurethane elastic fiber to swell in the same manner as when the hydrophilic polyol is introduced. It induces post-processing problems such as yarn breakage and poor quality due to scum adhesion. Above all, only moisture absorption performance is insufficient, and a moisture absorption rate at 20 ° C. × 65% RH is only about 4.0% by weight. If the mixing ratio of the superabsorbent polymer is increased in order to increase the hygroscopicity, the problem that the high elongation property of the yarn, particularly the elongation, is not solved.
[0006]
On the other hand, in recent years, there has been an increasing demand for heat resistance of polyurethane-based elastic fibers, and polyurethane-based elastic fibers that can be knitted and woven with polyester fibers that particularly require high-temperature and high-pressure dyeing have long been desired. In response to such demands, a technique for forming a polyurethane polymer from a polyurethane solution and then increasing the molecular weight by heat treatment is known as a technique for improving the heat resistance of polyurethane-based elastic fibers (see, for example, Patent Documents 3 and 4). . However, polyurethane-based elastic fibers based on these technologies have increased heat resistance to heat treatment in post-processing, but it is difficult to control the amount of dough according to the purpose, resulting in poor yield and problems in post-processing passability. It was.
[0007]
Further, when the above-described hydrophilicity is introduced into the polyol component, there is a problem that the heat resistance to the heat treatment received in the post-processing is lowered, and it becomes difficult to knitted with polyester fibers that require high-temperature and high-pressure dyeing.
[0008]
[Non-Patent Document 1]
Dyeing Industry, Vol. 47, no. 10,491
[Patent Document 1]
JP-A-11-81046 (Claim 1 etc.)
[Patent Document 2]
JP 2001-98423 A (Claims etc.)
[Patent Document 3]
JP-A-5-186557 (Claims 1, 0006, 0031, etc.)
[Patent Document 4]
Japanese Patent Laid-Open No. 7-102035 (Claims 1, 0003, 0025, etc.)
[0009]
[Problems to be solved by the invention]
An object of the present invention is to quickly remove water vapor generated by sweating during exercise from the skin, and is suitable for stretch clothes that do not get steamed. It is to provide a woven or knitted fabric using elastic fibers.
[0010]
[Means for Solving the Problems]
As a result of diligent efforts to solve the above problems, the present inventors have made the present invention. That is, the present invention has the following configuration.
1. A polyurethane-based elastic fiber with improved moisture absorption / release characteristics, wherein the moisture absorption at 20 ° C. × 65% RH is 4.5% by weight or more.
2. Fiber surface area of 0.110m ² The polyurethane elastic fiber having improved moisture absorption / release properties as described in the above item 1, characterized by being / g or more.
3. 3. The polyurethane elastic fiber having improved moisture absorption and desorption characteristics according to the first or second aspect, wherein the fiber cross section is an irregular cross section having an irregularity degree of 1.3 or more.
4). The hygroscopic property according to any one of the first to third aspects, wherein the polyurethane-based elastic fiber contains a highly hygroscopic organic material insoluble in dimethylacetamide and has a breaking elongation of 450% or more. Polyurethane elastic fiber.
5. The polyurethane-based elastic fiber contains highly hygroscopic fine particles, the high hygroscopic fine particles have an average particle size of 20 μm or less, a swelling degree of 200% or less, and a moisture content at 20 ° C. × 65% RH of 30%. The moisture absorption / release property according to any one of the first to fourth aspects is improved, wherein the high moisture absorption / release fine particles are contained in an amount of 0.2 to 50% by weight based on the fiber weight. Polyurethane elastic fiber.
6). A crosslinked structure is introduced into the acrylonitrile polymer in which the highly hygroscopic fine particles contain 50% by weight or more of acrylonitrile by hydrazine, divinylbenzene or triallyl isocyanurate treatment, and the remaining nitrile group is converted into a salt-type carboxyl group by hydrolysis. The polyurethane-based elastic material having improved moisture absorption / release properties according to the above item 5, which is chemically converted and is a high moisture absorption / release organic fine particle having a salt-type carboxyl group of 1.0 mmol / g or more. fiber.
7. A woven or knitted fabric characterized in that the polyurethane elastic fiber according to any one of the first to sixth aspects is used at least in part.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
First, as a measure for imparting hygroscopicity, it is effective to add and mix a hygroscopic compound to a polyurethane polymer which is a raw material for polyurethane-based elastic fibers or a polyurethane polymer solution thereof, and then spin. A method of adhering a highly hygroscopic agent or the like to the fabric surface by padding using a binder or the like is also conceivable. However, there is a problem that the texture is liable to be lost. There is a problem that durability tends to be insufficient, which is not preferable. Polyurethane elastic fibers have the advantage that they are not exposed to the surface of the fabric in a normal method of use and do not impair the texture, and it can be said that it is a preferred embodiment to contain a highly hygroscopic agent inside the polyurethane elastic fibers. Spinning can be carried out by any of dry spinning, wet spinning and melt spinning. Examples of the hygroscopic compound are highly hygroscopic fine particles such as polyacrylic acid polymer fine particles, polyvinyl polymer fine particles, polyamide polymer fine particles, polyurethane polymer fine particles, porous silica fine particles, and prevents deterioration of physical properties, In order to improve spinning operability and processability, it is more preferable that the particle diameter of the fine particles is 20 μm or less, preferably 10 μm or less, 5 μm or less. Most preferably, it is 2 μm or less. This is because, in order to achieve the above-mentioned purpose, it is necessary to disperse the highly hygroscopic fine particles in the fiber during the spinning process. When the particle diameter is larger than 20 μm, it may cause the spun yarn breakage or the yarn breakage in the post-processing. However, if the average particle size is too small, aggregation between the fine particles tends to occur and the dispersibility in the polyurethane-based elastic fiber is deteriorated. Therefore, the average particle size is preferably 0.1 μm or more.
[0012]
The content of the highly hygroscopic fine particles to the polyurethane elastic fiber is preferably 0.2% by weight or more. More preferably, it is 0.5 weight% or more. If it is less than 0.2% by weight, the hygroscopicity becomes poor, which is not preferable. However, if the content is too large, the spinnability at the spinning stage is lowered and the number of broken yarns is increased. Therefore, the content is preferably 50% by weight or less, more preferably 48% by weight or less.
[0013]
The degree of swelling of the highly hygroscopic fine particles preferably used in the present invention is preferably 200% or less, and more preferably 100% or less. If the degree of swelling exceeds 200%, the polyurethane-based elastic fiber itself swells due to moisture, which causes thread breakage due to scum adhesion during covering and knitting, and poor quality. The smaller the degree of swelling of the highly hygroscopic fine particles, the better. In the polyurethane elastic fiber of the present invention, the swelling due to moisture absorption occurs only in the high moisture absorption / release organic fine particles only, and the polyurethane polymer forming the fiber hardly swells due to moisture absorption. There is little problem in post-processing due to yarn breakage and poor quality due to scum adhering to the surface.
[0014]
The highly hygroscopic organic fine particles preferably used in the present invention are preferably non-biological polymer high hygroscopic organic fine particles because of their high moisture content at 20 ° C. and 65% RH. However, the moisture content of the highly hygroscopic organic fine particles at 20 ° C. × 65% RH is preferably 30% or more. More preferably, it is 35% or more, and most preferably 40% or more. Conventionally, among the fine particles considered to be hygroscopic, wool powder and keratin powder are considered to have the highest hygroscopicity, but the moisture content at 20 ° C. × 65% RH is at most 15%. . In addition, polysaccharide fine particles such as starch, cellulose, silk, and collagen, and protein fine particles are about 8 to 12% smaller than the above-described wool powder and keratin powder. Although there are other urea resin-based and melamine resin-based powders, the moisture content at 20 ° C. × 65% RH is considered to be as little as 30%, which is not preferable.
[0015]
The polyurethane elastic fiber of the present invention preferably has a moisture absorption rate of 4.5% or more at 20 ° C. × 65% RH. The moisture absorption at 20 ° C. × 65% RH is more preferably 5.0% or more, and the moisture absorption at 20 ° C. × 65% RH is most preferably 6.0 or more. If it is less than 4.5%, a comfortable hygroscopic property cannot be obtained, which is not preferable. However, if the moisture absorption rate is too high, a feeling of nulliness appears on the fiber surface, and therefore it is preferably 9.0% or less. On the other hand, if it exceeds 9.0%, the elongation at break tends to be less than 450%, and it is difficult to obtain an elastic fiber for various applications. Note that the elongation at break is particularly preferably 500% or more because the texture is good, and is preferably 800% or less because of the ease of stretch control of the woven or knitted fabric.
[0016]
The polyurethane elastic fiber of the present invention has a fiber surface area of 0.110 m. ² / G or more is preferable. When the fiber surface area is increased, highly moisture-absorbing / releasing fine particles are likely to appear on the fiber surface, and the moisture-absorbing / releasing property is improved accordingly. 0.500m ² / G or more is not preferable because the elongation at break tends to be a small value of less than 450%. A more preferable range is 0.130 to 0.400 m. ² / G.
[0017]
The polyurethane elastic fiber of the present invention preferably has a deformed cross section having a deformity of 1.3 or more. This has a large relationship with the fiber surface area, but also has a relationship with the elongation at break. Although the fiber surface area can be increased by reducing the single yarn fineness, in that case, the elongation at break tends to be less than 450%, which makes it difficult to use in various applications. However, it is preferable to increase the fiber surface area by setting the profile to 1.3 or more because the elongation at break tends to be 450% or more. More preferably, it is a deformed cross section having a deformity of 1.5 or more. However, if the degree of deformation exceeds 10, it is not preferable because spun yarn breakage tends to occur frequently.
[0018]
The polyurethane polymer used for the polyurethane-based elastic fiber of the present invention is a polymer intermediate obtained by reacting a polyol with an excess of a diisocyanate compound and having both ends of an isocyanate group, N, N′-dimethylacetamide, dimethyl It can be obtained by dissolving in an organic solvent such as sulfoxide, cooling the polymer solution, and then reacting the diamine compound.
[0019]
Although there is no restriction | limiting in particular as said polyol, For example, polymer diol etc. are mentioned. Specifically, polyether diols such as polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxypentamethylene glycol and polyoxypropylene tetramethylene glycol, adipic acid, sebacic acid, maleic acid, itaconic acid , One or more dibasic acids such as azelaic acid and malonic acid and ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2,2-dimethyl-1,3-propanediol, 1, Polyester diol, poly-ε-caprolactone and polyvalerola obtained from one or more glycols such as 4-butanediol, 2,3-butanediol, hexamethylene glycol and diethylene glycol Polylactone diols such as tons, polyesteramide diols, polyether ester diols can be selected from polycarbonate diol. Alternatively, a mixture of these may be used.
[0020]
The diisocyanate compound is not particularly limited as long as it is an aliphatic, alicyclic or aromatic diisocyanate compound. For example, methylene-bis (4-phenylisocyanate), methylene-bis (3-methyl-4-phenylisocyanate), 1,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m- and p-phenylene diisocyanate, m- and p-xylylene diisocyanate, methylene-bis (4-cyclohexylisocyanate), 1,3- and 1,4-cyclohexylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and the like. .
[0021]
The diamine compound as a chain extender is not particularly limited, but for example, ethylenediamine, propylenediamine, trimethylenediamine, hexamethylenediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexane Examples include diamine and hydrazine. A mixture of these may also be used. In addition to diamines, diols such as 1,4-butanediol, ethylene glycol, and water may be used.
[0022]
The highly hygroscopic fine particles that can be preferably used for the polyurethane elastic fiber of the present invention are preferably high hygroscopic organic fine particles composed of a non-biological polymer. The acrylonitrile polymer containing 50% by weight or more of acrylonitrile is added with hydrazine, divinyl. A crosslinked structure is introduced by treatment with benzene or triallyl isocyanurate, and the remaining nitrile group is chemically converted to a salt-type carboxyl group by hydrolysis, and has a salt-type carboxyl group of 1.0 mmol / g or more. It is preferable. More specifically, (a) an acrylonitrile-based polymer containing 85% by weight or more of acrylonitrile is subjected to hydrazine treatment so that the increase in nitrogen content is 1.0 to 15.0. Acrylic metal conversion particles obtained by introducing a crosslinked structure and chemically converting the remaining nitrile group into a salt-type carboxyl group by hydrolysis, and having a salt-type carboxyl group of 1.0 mmol / g or more, (b ) An acrylonitrile-based polymer introduced with a crosslinked structure of divinylbenzene or triallyl isocyanurate and containing 50% by weight or more of acrylonitrile, wherein the remaining nitrile group is chemically converted to a salt-type carboxyl group by hydrolysis An acrylic metal group having a salt-type carboxyl group of 2.0 mmol / g or more. Such as particles, and the like. The upper limit of the salt-type carboxyl group amount is usually 15 mmol / g or less.
[0023]
These metal conversion particles are crosslinked acrylic polymer fine particles. In the acrylonitrile polymer as the starting fine particles, monomers used in combination with acrylonitrile include vinyl halide, vinylidene halide, acrylic ester, methacrylic ester, Examples include sulfonic acid-containing monomers such as p-styrenesulfonic acid and salts thereof, carboxylic acid-containing monomers such as acrylic acid and salts thereof, acrylamide, styrene, vinyl acetate, and the like.
[0024]
When spinning polyurethane-based elastic fibers by the dry spinning method, the reason and mechanism cannot be analyzed well by adding high-grade moisture-releasable organic substances that are insoluble in organic solvents. Since it exists, it tends to be a fiber excellent in moisture absorption and desorption. In the case of an organic substance soluble in an organic solvent, when it is within the range of changing the normal spinning conditions, the organic substance having hygroscopic properties tends to exist almost evenly within the fiber cross section. However, in the case of a high-grade moisture-releasing organic substance that is insoluble in an organic solvent as in the present invention, uneven distribution on the fiber surface side where the fluid velocity in the nozzle is relatively low tends to proceed. This not only efficiently exhibits moisture absorption and desorption, but also prevents a decrease in the strength and elongation properties of the fiber. Therefore, in the elastic fiber of the present invention, in particular, organic fine particles insoluble in dimethylacetamide, an organic solvent for polyurethane, are present. Preferably employed.
[0025]
Next, the counterpart material to be woven and woven with the polyurethane elastic fiber of the present invention will be described. The unwoven fabric material may be any of thermoplastic synthetic fiber, natural fiber, and regenerated fiber. For thermoplastic synthetic fiber, polyester fiber represented by polyethylene terephthalate and polytrimethylene terephthalate, nylon 6 and nylon 66 In the case of natural fibers, cotton, wool, and regenerated fibers are preferably employed as rayon and polynosic fibers.
[0026]
There are no particular restrictions on the cross-weaving of the partner material and polyurethane elastic fiber.For example, when cross-weaving, when covering the partner material to the polyurethane elastic fiber, the polyester fiber is covered with the polyurethane elastic fiber. It is generally used for warp and / or weft. Further, when knitting with the partner material, it is possible to knit in directly with the partner material or knit in with the covering yarn.
[0027]
For dyeing processing of stretch woven and knitted fabrics obtained by this method, it is possible to adopt a general processing process that relaxes and scours the raw machine, pre-sets it, dyes it, dries it, finishes it, and finishes it. is there.
[0028]
【Example】
The present invention will be specifically described below with reference to examples. Measurement methods, evaluation methods, etc. are as follows.
[0029]
(A) Swelling degree of fine particles
About 1 g of the sample that has been completely dried for 24 hours in a drier set at 105 ° C. is placed in a 10 ml screw tube, held vertically, the sample upper surface is made as flat as possible, and the volume V1 (ml) at that time is read from the scale. . An amount of pure water whose water level is higher than the upper surface of the sample even after water absorption is put into the screw tube, and left for 6 hours vertically, and then the volume V2 (ml) of the upper surface of the sample is read from the scale. The degree of swelling of the fine particles is determined by the following formula (1).
Swelling degree (%) = {(V2−V1) / V1} × 100 (1)
[0030]
(B) Moisture absorption rate
After washing 5 g of polyurethane-based elastic fiber with 100 ml of petroleum ether, the weight W1 (g) in the absolutely dry state is measured. The weight W2 (g) after being left for 24 hours in an atmosphere of 20 ° C. × 65% RH is measured, and the moisture absorption rate at 20 ° C. × 65% RH is determined by the following formula (2).
20 ° C. × 65% RH, moisture absorption rate (%) = {(W 2 −W 1) / W 1} × 100 (2)
[0031]
(C) Elongation at break (%)
Using a tensile tester, Tensilon, manufactured by Orientec Co., Ltd., a tensile test was conducted at a distance between chucks (sample length) of 50 mm, a tensile speed of 500 mm / min, and a chart feed speed of 250 mm / min. Read directly from the sheet to obtain the elongation at break.
[0032]
(D) Fiber surface area
The cross-sectional perimeter L (m) of the fiber was measured with an image processing device from a cross-sectional enlarged photograph taken with an optical microscope or a scanning electron microscope, and the fiber surface area was calculated.
Fiber surface area (m ² / G) = L × 10000 / (single fiber fineness [dtex])
(The single fiber fineness is obtained by dividing the total fineness [dtex] of the yarn by the number of filaments counted from the cross-sectional enlarged photograph.)
[0033]
(E) Deformity
A section of the fiber cross section is made and observed with a photograph, the maximum inscribed circle diameter and circumscribed circle diameter of the single yarn section are measured, and the degree of deformity of the single fiber is calculated by the ratio of the circumscribed circle diameter to the maximum inscribed circle diameter.
[0034]
(F) Moisture content of fine particles
Approximately 2g of sample was collected in a petri dish that had been washed and completely dried, covered with aluminum foil with a small hole in it, and a thermo-hygrostat set to 20 ° C x 65% RH, taking care not to scatter particles Measure the petri dish weight W3 after 24 hours
The Thereafter, the weight W4 (g) of the petri dish after being placed in a dryer set at 105 ° C. for 24 hours is measured. The moisture content of the fine particles at 20 ° C. × 65% RH is obtained by the following formula (3).
Moisture content (%) = {(W3-W4) / W4} × 100 (3)
[0035]
(G) Salt type carboxyl group concentration in fine particles
About 1 g of sufficiently dried test fine particles are precisely weighed (X (g)), 200 g of water is added thereto, 1N hydrochloric acid aqueous solution is adjusted to pH 2 while heating to 50 ° C., and then 0 A titration curve was obtained according to a conventional method using a 1N sodium hydroxide aqueous solution. From this titration curve, the consumption amount (Y (cc)) of aqueous sodium hydroxide solution consumed by carboxyl groups was determined, and the carboxyl group concentration was calculated by the following formula (4).
Carboxyl group concentration = 0.1 × Y / X (4)
Separately, in the above carboxyl group content measurement operation, a titration curve was similarly obtained without adjusting to pH 2 by adding a 1N hydrochloric acid aqueous solution, and a carboxylic acid concentration was obtained. From these results, the salt-type carboxyl group concentration was calculated by the following formula (5).
Salt type carboxyl group concentration = carboxyl group concentration−carboxylic acid concentration (5)
[0036]
(H) Weight average molecular weight and molecular weight distribution of polyurethane polymer
The molecular weight was measured using gel permeation chromatography (GPC), using a column TSKgel (R) GMHXL manufactured by Tosoh Corporation, with a column temperature of 40 ° C. and a flow rate of 0.7 ml / min detector RI. A weight average molecular weight (MW) and a number average molecular weight (MN) are obtained, and the ratio (MW / MN) is obtained as a molecular weight distribution.
[0037]
(I) Method for confirming that it is insoluble in dimethylacetamide, a highly hygroscopic organic substance
In an environment of 20 ° C., 1 g of organic substance is put into 1 liter of dimethylacetamide in a beaker and stirred for 1 hour. Thereafter, the organic substance is filtered through a filter paper, and left to dry in an environment of 20 ° C. and 65% RH for 24 hours. Thereafter, the weight of the filter paper is measured, and the weight of the organic matter W5 (g) is calculated by subtracting the weight of only the filter paper that was initially measured.
Based on the following formula (6), it is assumed that an organic substance having a solubility of 10% or less is insoluble.
Solubility (%) = (1−W5) × 100 (6)
[0038]
(Example 1)
200 parts of polyoxytetramethylene glycol having a molecular weight of 1800 and 45 parts of methylene-bis (4-phenylisocyanate) were reacted at 80 ° C. for 3 hours to obtain an intermediate polymer having both terminal isocyanate groups. After the intermediate polymer was cooled to 40 ° C., 375 parts of N, N-dimethylacetamide was added and cooled to 10 ° C. Prepare a diethylamine solution in which 4.0 parts of ethylenediamine and 0.4 parts of diethylamine are dissolved in 147.6 parts of N, N-dimethylacetamide, and add the diethylamine solution to the rapidly stirring intermediate polymer solution at a stretch. A polyurethane polymer solution of 32.2% by weight and a viscosity of 2500 poise (30 ° C.) was obtained.
[0039]
To the polyurethane polymer solution thus obtained, 4% of an n-butylamine / N, N-dimethylhydrazine end-capped polymer, a benzotriazole compound, and a hindered phenol compound are added and mixed. (The weight average molecular weight of the polyurethane polymer was 200,000, and the molecular weight distribution (MW / MN) was 2.3.)
[0040]
Subsequently, a raw material fine particle aqueous dispersion composed of acrylonitrile, methyl acrylate, p-styrene sulfonic acid soda and water was crosslinked with hydrazine and hydrolyzed with NaOH. Average particle diameter of 0.5 μm (measured with a light scattering photometer) Highly hygroscopic organic fine particles having a degree of swelling of 80%, moisture content at 20 ° C. × 65% RH of 45% (insoluble in dimethylacetamide, sodium salt type carboxyl group content was 5.4 mmol / g .) Was added to and mixed with 10% by weight of the polyurethane polymer solution to obtain a spinning dope.
[0041]
The spinning solution was defoamed and then discharged from a die having a Y-shaped slit, extruded into a spinning cylinder in which heated air of 235 ° C. was flown, and 5% by weight of oil was applied and wound at a take-up speed of 550 m / min. . The obtained yarn was heat-treated at 40 ° C. for 72 hours to obtain 33 dtex, 3-filament polyurethane elastic fiber for post-processing. The moisture absorption rate of this polyurethane elastic fiber at 20 ° C. × 65% RH is 6.5%, the elongation at break is 580%, the deformity is 1.5%, and the fiber surface area is 0.15 (m ² / G). From the cross-sectional photograph, it was observed that hygroscopic fine particles are unevenly distributed on the fiber surface side.
[0042]
The resulting polyurethane elastic fibers and 44 dtex polyester filaments were knitted into 2 weight ricots, and relaxed, pre-set at 185 ° C-45 seconds, disperse dyed at 130 ° C-30 minutes, and final set for 40 seconds. A processed dough was obtained. Women's shorts were made using this fabric, and a wearing test of 20 people was conducted. Of the 20 subjects, 16 experienced an improvement in stuffiness.
[0043]
(Example 2)
Spinning and post-processing were performed under the same conditions as in Example 1 except that the nozzle was changed to a round cross-section nozzle and made into a 33 dtex 4-filament round cross-section fiber to obtain a 2-weight recot dough. This polyurethane elastic fiber has a moisture absorption rate at 20 ° C. and 65% RH of 4.7%, a breaking elongation of 610%, an irregularity of 1.0%, and a fiber surface area of 0.118 (m ² / G). Women's shorts were made using this fabric, and a wearing test of 20 people was conducted. Of the 20 test subjects, 14 experienced an improvement in stuffiness.
[0044]
(Example 3)
30% by weight of the same highly hygroscopic organic fine particles as in Example 1 were added to and mixed with the polyurethane polymer solution to obtain a spinning dope. Spinning and post-processing were performed under the same conditions as in Example 2 to obtain a two-weight ricot fabric. The moisture absorption rate of this polyurethane elastic fiber at 20 ° C. × 65% RH is 7.3%, the breaking elongation is 460%, the deformity is 1.0%, and the fiber surface area is 0.110 (m ² / G). Women's shorts were made using this fabric, and a wearing test of 20 people was conducted. Of the 20 subjects, 18 experienced an improvement in stuffiness.
[0045]
(Comparative Example 1)
5% by weight of urethane water-absorbing resin (soluble in dimethylacetamide) having a water absorption of 2000% by weight comprising polyethylene glycol having an average molecular weight of 6000, 1,4-butanediol and 4,4′-diphenylmethane diisocyanate Spinned and post-processed under the same conditions as in Example 2 except that it was added to and mixed with the polyurethane polymer solution to obtain a spinning stock solution, the heating air temperature was 280 ° C., and the winding speed was 550 m / min. I got the dough. The moisture absorption rate of this polyurethane elastic fiber at 20 ° C. × 65% RH is 2.9%, the breaking elongation is 490%, the deformity is 1.0%, and the fiber surface area is 0.117 (m ² / G). Women's shorts were made using this fabric, and a wearing test of 20 people was conducted. Of the 20 test subjects, only 2 experienced improvement in stuffiness.
[0046]
(Comparative Example 2)
15% by weight of urethane-based water-absorbing resin was added to and mixed with the polyurethane polymer solution to make a spinning stock solution, except that 44 dtex 4-filament was used. A two-weight ricot fabric was obtained. This polyurethane elastic fiber has a moisture absorption rate at 20 ° C. and 65% RH of 4.0%, a breaking elongation of 390%, a deformity of 1.0%, and a fiber surface area of 0.101 (m ² / G). Women's shorts were made using this fabric, and a wearing test of 20 people was conducted. Of the 20 subjects, only 4 people could feel the improvement of stuffiness.
[0047]
(Comparative Example 3)
Spinning and post-processing were carried out under the same conditions as in Example 1 except that the urethane mixed solution in Comparative Example 1 was used to obtain a 2-weight recot dough. The moisture absorption rate of this polyurethane elastic fiber at 20 ° C. × 65% RH is 3.9%, the breaking elongation is 310%, the deformity is 1.5%, and the fiber surface area is 0.15 (m ² / G). Women's shorts were made using this fabric, and a wearing test of 20 people was conducted. Of the 20 test subjects, only 5 improved the feeling of stuffiness. Moreover, the fall of the stretch property of a fabric was remarkable and the texture became hard.
[0048]
【The invention's effect】
According to the present invention, polyurethane-based elastic fibers having good post-processing passability, excellent heat resistance, and quickly removing moisture generated by sweating during exercise from the skin and rich in elasticity that does not stuffy and its woven or knitted fabric Is now available.

Claims (7)

A polyurethane-based elastic fiber with improved moisture absorption / release characteristics, wherein the moisture absorption at 20 ° C. × 65% RH is 4.5% by weight or more. ^{2. The} polyurethane elastic fiber with improved moisture absorption / release characteristics according to claim 1, wherein the surface area of the fiber is 0.110 m ² / g or more. 3. The polyurethane elastic fiber with improved moisture absorption / release characteristics according to claim 1 or 2, wherein the fiber cross section is an irregular cross section having an irregularity of 1.3 or more. The hygroscopic property according to any one of claims 1 to 3, wherein the polyurethane elastic fiber contains a highly hygroscopic organic material insoluble in dimethylacetamide and has a breaking elongation of 450% or more. Polyurethane elastic fiber. The polyurethane-based elastic fiber contains highly hygroscopic fine particles, the high hygroscopic fine particles have an average particle size of 20 μm or less, a swelling degree of 200% or less, and a moisture content at 20 ° C. × 65% RH of 30%. 5. The polyurethane with improved moisture absorption / release characteristics according to any one of claims 1 to 4, wherein the high moisture absorption / release fine particles are contained in an amount of 0.2 to 50% by weight based on the fiber weight. Elastic fiber. A crosslinked structure is introduced into the acrylonitrile polymer in which the highly hygroscopic fine particles contain 50% by weight or more of acrylonitrile by hydrazine, divinylbenzene or triallyl isocyanurate treatment, and the remaining nitrile group is converted into a salt-type carboxyl group by hydrolysis. 6. The polyurethane-based elastic material with improved moisture absorption / release properties according to claim 5, which is a chemically converted organic fine particles with high moisture absorption / release properties having a salt-type carboxyl group of 1.0 mmol / g or more. fiber. A woven or knitted fabric characterized in that the polyurethane elastic fiber according to any one of claims 1 to 6 is used at least in part.