JPH07316977A - Porous type hollow fiber and its production - Google Patents

Abstract

PURPOSE:To produce hollow fiber of porous type which is suitably useful as a material for woven and knitted fabrics excellent in see-through proofness, heat-retaining properties, light weight and water absorption by leaching out the island parts in a specific sea-island type conjugated fiber. CONSTITUTION:A polymer resistant to alkali at >=30% water absorption, for example, a saponified ethylene-vinyl alcohol copolymer is used as a sea component, while a polymer having an alkaline dissolution rate ranging from 30X10<-8> to 130X10<-8>cm/sec in 40g/l aqueous NaOH at 80 deg.C, for example, a polyethylene terephthalate copolymer copolymerized with 5-sodiumsulfoisophthalic acid, a polyethylene glycol and an oyxyalkylene group-compound is used as an island component to give a conjugated fiber of sea-island type. The conjugated fibers are treated with an alkali to leach out the island component to give hollow fiber of porous type satisfying the expression 1-<=2[X/(npi)]<1/2=10 where X is the total area of the hollow part on the fiber cross section in mu<2>, (n) is a number of the hollow parts and an integer of 2 or more in the hollow part of the cross-section perpenclicular to the fiber axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-transparent property utilizing the effect of increasing the amount of light reflection due to the multi-layered air layer, and at the same time, heat retention and light weight utilizing the heat insulating effect of the air layer, The present invention relates to a porous hollow fiber that gives a woven or knitted fabric excellent in water absorption and the like.

Due to their excellent physical and chemical properties, synthetic fibers such as polyester and polyamide are widely used not only for clothing but also for industry and have industrially important value. However, since these synthetic fibers have a large single yarn fineness, a simple cross-sectional shape, and a uniform and simple internal structure on the surface, they have a plastic-like cold feeling, and are It has the drawback that the warmth and heat retention of clothing are insufficient. In addition, it has poor water absorbency, and when it is used as clothing for summer, it has a drawback that it tends to get stuffy when worn in an environment of high temperature and high humidity and is inferior in comfort. Further, in the case of using thin cloth for inner wear, it has a defect that it is easily transparent.

Therefore, in order to improve the above-mentioned drawbacks of synthetic fibers, it is common to compound a plurality of polymers into a composite fiber, to deform the cross section of the synthetic fiber, or to hollow the fiber. Has been done. However, a fiber having a good feeling with swelling, which has properties such as a refreshing feeling, water absorption, heat retention, lightness, transparency prevention, and bulkiness, has not yet been obtained.

When the fiber is made hollow, especially when the hollow portion is porous, it can be produced by discharging the polymer from a hollow spinning nozzle having a porous shape. However, even if a porous hollow shape is once formed in the fiber, the hollowness of the porous portion is apt to decrease due to the surface tension of the polymer in a molten state or the take-up tension during spinning before solidification. When the portions are close to each other, it is difficult to obtain a porous hollow fiber having a cross-sectional shape in which each hole is easily communicated with each other.

In order to solve the above-mentioned difficulties in the yarn-making stage, sea-island type composite fibers containing polyamide as a sea component and polymers such as polyethylene and polystyrene as an island component are treated with an organic solvent such as toluene and parkene. Has proposed a method of dissolving and removing the island component polymer. However, in this method, an organic solvent such as toluene or perylene is used, which is not preferable in terms of working environment. In addition, special equipment is required as a work environment improvement measure, and in reality, there are restrictions on the places where such organic solvent treatment is possible.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a porous hollow fiber which provides a woven or knitted fabric or the like having properties such as anti-seepage property, refreshing feeling, heat retaining property, water absorption property and light weight property. The present invention also provides a method for obtaining the fiber without causing problems in polymer design, fiberizing process, working environment in processing process, and the like.

[0007]

The present invention has a water absorption of 3%.
A porous hollow fiber made of an alkali-resistant polymer as described above, characterized in that the hollow portion in a cross section perpendicular to the fiber axis of the fiber satisfies the following formula [I]: And

[0008]

[Equation 2] [However, x is the total cross-sectional area (μ ² ) of the hollow portion, and n is the number of hollow portions and is an integer of 2 or more. ]

When an alkali resistant polymer having a water absorption rate of 3% or more is used as a sea component and treated with an aqueous sodium hydroxide solution having a concentration of 40 g / l at a temperature of 80 ° C., an alkali dissolution rate constant is 30 × 10 ^{−. 8 to} 130 × 10 ^-8 cm / se
This is a method for producing a porous hollow fiber, which comprises spinning sea-island composite fibers containing a polyester in the range of c as an island component, and then treating the same with an alkaline aqueous solution to decompose and elute the island component polyester.

It is important that the alkali-resistant polymer according to the present invention is a polymer having a water absorption rate of 3% or more. Here, the "water absorption" is the water absorption in the form of a film having a thickness of 15 µ. When the polymer has a water absorption rate of less than 3%, when the sea-island composite fiber is treated with an alkaline aqueous solution to produce a porous hollow fiber, the alkaline aqueous solution easily diffuses and passes through the polymer which is a sea component. I can't
The island component polyester cannot be dissolved and removed. It is also important that the sea component polymer is alkali resistant in order to avoid deterioration and damage during the treatment with an alkaline aqueous solution. "Alkali resistant polymer" means 100
1 shows a polymer having a weight loss rate of 0 with an aqueous sodium hydroxide solution under the conditions of a temperature of 40 ° C., a concentration of 40 g / l, and a treatment time of 1 hour.

As the alkali resistant polymer having a water absorption rate of 3% or more, polyamides such as nylon 6, nylon 66 and nylon 610, and ethylene vinyl alcohol are used.
Among them, ethylene-based copolymers are preferable, but ethylene-vinyl alcohol-based copolymers having an ethylene content of less than 75 mol% and a saponification degree of 95% or more are preferable. The degree of polymerization of these polymers is within the range used for general clothing, as long as fiber formation is possible. It should be noted that ordinary additives for fibers such as a matting agent such as titanium oxide, an ultraviolet absorber and an antioxidant may be added to these polymers.

The hollow portion in the porous hollow fiber of the present invention must satisfy the following formula [I].

[0013]

[Equation 3] [However, x is the total cross-sectional area (μ ² ) of the hollow portion, and n is the number of hollow portions and is an integer of 2 or more. ]

When the value represented by the formula [I] is less than 1, the hollow portion is likely to be crushed during a processing step such as dyeing, and functions such as heat retention, light weight, and see-through preventing property are lost.
On the other hand, when the value exceeds 10, the strength of the porous hollow fiber is extremely lowered, and it cannot be used as a woven or knitted material.
Considering performances such as fiber strength, heat retention, lightness, and transparency prevention, the value is preferably in the range of 2 to 7.

The number of n is an integer of 2 or more, but an integer of 5 or more, particularly an integer of 10 or more is preferable in order to further satisfy the effects such as heat retention, lightness and sheer prevention. preferable. The upper limit of n is not particularly limited, but it is preferably 100 or less, and particularly preferably 80 or less in consideration of the decrease in strength of the resulting porous hollow fiber and the cost of the spinning nozzle.

The hollow ratio of the hollow portion in the porous hollow fiber of the present invention is preferably in the range of 30 to 70% from the viewpoint of the effect and the manufacturing process. If the hollow ratio is less than 30%, the resulting porous hollow fibers are likely to lack functions such as heat retention, lightness, and see-through prevention. On the other hand, the hollow ratio is 70
If it exceeds%, the yarn strength may remarkably decrease and the durability of use as a fiber or a textile product such as a woven or knitted product may decrease. Considering the heat retaining property, the sheer preventing property, and the yarn strength, the hollow ratio is particularly preferably in the range of 40 to 60%.

The polyester constituting the island component of the sea-island type composite fiber according to the present invention has an alkali solubility constant of 30 × 10 ^{-8 to} 130 when treated with an aqueous sodium hydroxide solution having a temperature of 80 ° C. and a concentration of 40 g / l. × 10 ^-8 cm / sec
It is important to be in the range of. The composition of the polyester is not particularly limited as long as the polyester has such an alkali dissolution rate constant.

The alkali solubility constant in the present invention is a value represented by the following formula [II].

[Equation 4] Under the above conditions, the value of the alkali solubility constant is 3
When it is less than 0 × 10 ⁻⁸ cm / sec, it takes a long time to treat 100% of this polyester, which is an island component, with an alkaline aqueous solution to dissolve and elute, and a high temperature is required. This causes deterioration of a certain polymer.
On the other hand, the value of alkali solubility constant is 130 × 10 ^-8 cm /
If it exceeds sec, when the composite fiber containing the polyester as the island component is spun, many yarn breakages occur and the spinning becomes impossible. In order to improve the spinnability of the composite fiber and prevent the deterioration of the sea component, it is preferable that the value of the alkali solubility constant under the conditions is in the range of 40 × 10 ^{−8 to} 100 × 10 ⁻⁸ cm / sec. .

Examples of the polyester having such an alkali dissolution rate constant include polyesters known as easily alkali-soluble polyesters, for example, polyesters obtained by copolymerizing isophthalic acid, alkylene glycol, sulfoisophthalic acid alkali metal salt and the like. You can Among them, ethylene terephthalate is a main repeating unit, and a sulfonate group-containing compound, a diol unit-containing compound represented by the following formula [b], and the following formula [c]
A polyester obtained by copolymerizing a side chain unit-containing compound represented by Hereinafter, this copolyester will be described. What is a sulfonate group-containing compound?
It is a compound containing a dicarboxylic acid unit represented by the following formula [a].

[0020]

[Chemical 1] (In the formula, Ar represents a trivalent aromatic group and M represents a metal atom.)

[0021]

[Chemical 2] (In the formula, R ¹ represents an alkylene group, and m represents a number of 10 to 100)

[0022]

[Chemical 3] (In the formula, R ² represents an alkylene group, R ³ represents a hydrocarbon group having 1 to 18 carbon atoms, n represents a number of 10 to 100, and x and y each represent 0 or 1.)

The dicarboxylic acid unit represented by the above formula [a] is 0.5 to 0.5 of all the acid components constituting the copolyester.
10 mol%, the diol unit represented by the formula [b] and the side chain unit represented by the formula [c] are respectively contained in an amount of 1 to 20% by weight based on the weight of the copolyester, and represented by the formula [b]. A copolymerized polyester in which the total content of the diol unit and the side chain unit represented by the formula [c] is 2 to 40% by weight based on the weight of the copolymerized polyester is preferable.

In the above-mentioned copolymerized polyester, the dicarboxylic acid unit represented by the above formula [a] [hereinafter referred to as "dicarboxylic acid unit [a]"] constitutes the copolymerized polyester as the dicarboxylic acid unit constituting the copolymerized polyester. It is preferably contained in a proportion of 0.5 to 10 mol%, particularly 1 to 7 mol%, based on the total acid components. Dicarboxylic acid unit [a]
When the copolymerization ratio of is less than 0.5 mol%, the copolymerized polyester becomes difficult to dissolve during alkali treatment, while when it exceeds 10 mol%, the copolymerized polyester is ionic interaction of the metal sulfonate component. Thickening occurs during the polycondensation reaction for producing the copolyester, and it becomes difficult to continue the polycondensation reaction until the copolyester has a desired intrinsic viscosity.

In the dicarboxylic acid unit [a], Ar is a trivalent aromatic group and M is a metal atom. As the group Ar, 1,3,5-benzenetriyl group, 1,2,3-
Benzenetriyl groups such as benzenetriyl group and 1,2,4-benzenetriyl group; 1,3,6-naphthalenetriyl group, 1,3,7-naphthalenetriyl group, 1,4
Examples thereof include a naphthalenetriyl group such as a 5-naphthalenetriyl group and a 1,4,6-naphthalenetriyl group. The metal atom M is an alkali metal atom such as sodium or lithium. The copolymerized polyester may have only one type of dicarboxylic acid unit [a] or may have two or more types of dicarboxylic acid unit [a].

The copolymerized polyester has ethylene terephthalate units as main repeating units, but as carboxylic acid units other than terephthalic acid and dicarboxylic acid units [a] which can be copolymerized, isophthalic acid and 1,4-naphthalene are used. Dicarboxylic acid, 1,5-naphthalenedicarboxylic acid,
2,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid,
Aromatic dicarboxylic acids such as 3,3′-biphenyldicarboxylic acid, 4,4′-diphenylisopropylidenedicarboxylic acid, 1,2-diphenoxyethane-4 ′, 4 ″ -dicarboxylic acid, and 2,5-anthracenedicarboxylic acid Aromatic hydroxycarboxylic acids such as β-hydroxyethoxybenzoic acid and p-oxybenzoic acid; or aromatic dicarboxylic acid units derived from ester-forming derivatives thereof; and aromatic dicarboxylic acid units thereof. Is 1
Only one kind or two or more kinds may be included. Along with the above-mentioned aromatic dicarboxylic acid units, aliphatic dicarboxylic acids such as adipic acid, azelaic acid and sebacic acid; and units derived from alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and ester-forming derivatives thereof may also be included. Good.

Further, the copolymerized polyester contains 1 to 20% of the diol unit represented by the above formula [b] [hereinafter referred to as "diol unit [b]"] based on the weight of the copolymerized polyester. When the proportion of the diol unit [b] is less than 1% by weight, the alkali solubility of the copolyester is lowered, while when it exceeds 20% by weight, spinnability may be difficult. In the diol unit [b], R ¹ is preferably an alkylene group having 1 to 4 carbon atoms, more preferably an ethylene group or a propylene group, and R ¹ is an ethylene group such as an alkali-soluble group. From the point, it is particularly preferable. In the diol unit [b], m indicating the degree of polymerization of the oxyalkylene unit is a number within the range of 10 to 100, and m is preferably a number within the range of 20 to 80, as described above. In the diol unit [b], when m is less than 10, the alkali solubility is low, while when m is more than 100, the alkali solubility is not much improved, and rather coloration is likely to occur. Examples of the diol unit [b] include units derived from polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene / polyoxypropylene glycol, etc., in which m is in the range of 10 to 100. In the copolymerized polyester, the diol unit [b] may be contained alone or in combination of two or more.

The copolymerized polyester may contain a diol unit other than ethylene glycol and the diol unit [b]. Examples of the other diol unit include propylene glycol, trimethylene glycol,
Aliphatic diols such as tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, nonamethylene glycol, 3-methylpentane-1,5-diol, 2-methyloctane-1,8-diol, diethylene glycol; cyclohexanedimethanol, etc. Examples thereof include units derived from alicyclic diols, and these diol units may be contained in one kind or in two or more kinds.

The copolymerized polyester further contains 1 to 20% by weight of the side chain unit represented by the above formula [c] [hereinafter referred to as "side chain unit [c]"] based on the weight of the copolymerized polyester. When the proportion of the side chain unit [c] is less than 1% by weight, the alkali solubility decreases, while when it exceeds 20% by weight, the spinnability becomes difficult. The side chain unit [c] is, for example, the following formula [d];

[0030]

[Chemical 4] [Wherein D is a group capable of reacting with a dicarboxylic acid component, a diol or the like to introduce the side chain unit [c] represented by the above formula [c] into the main chain of the copolyester, R ² , R ³ and n represent the same groups and numbers as above] and can be introduced into the copolyester by reacting the compound at the time of production of the copolyester.

In the compound represented by the above formula [d],
Examples of the ester-forming group D include, for example, the following formulas;

[Chemical 5] A glycidyl group represented by, or the following formula;

[Chemical 6] 2,3-dihydroxypropyl group and the like can be mentioned.

In the side chain unit [c], R ² has 1 carbon atom.
Is preferably an alkylene group of 4 to 4, more preferably an ethylene group or a propylene group, and particularly preferably an ethylene group. Further, as a specific example of R ³ , methyl,
Ethyl, n-propyl, isopropyl, n-butyl, s
ec-butyl, tert-butyl, n-pentyl, n-
Octyl, 2-ethylhexyl, n-dodecyl, n-
Examples thereof include alkyl groups such as stearyl; and aryl groups having 6 to 18 carbon atoms such as cyclohexyl. The side chain unit [c] may have an ethylene group and a propylene group in the same molecule. Furthermore, the side chain unit [c]
In, n showing the degree of polymerization of the oxyalkylene unit
Is in the range of 10 to 100, especially 20 to 8 as described above.
It is preferably a number in the range 0. When n is smaller than 10, the alkali solubility becomes small, while when n exceeds 100, the alkali solubility is not improved so much and it only causes coloring.

Specific examples of the side chain unit [c] include polyoxyethylene glycol-methyl-glycidyl ether and polyoxyethylene glycol-methyl-2,3-.
Dihydroxypropyl ether, polyoxyethylene glycol-ethyl-glycidyl ether, polyoxyethylene glycol-ethyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-n-propyl-glycidyl ether, polyoxyethylene glycol-n-propyl- 2,3-dihydroxypropyl ether, polyoxyethylene glycol-t-butyl-glycidyl ether, polyoxyethylene glycol-t-butyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-n-octyl-glycidyl ether, poly Oxyethylene glycol-n
-Octyl-2,3-dihydroxypropyl ether,
Polyoxyethylene glycol-2-ethylhexyl-
2,3-glycidyl ether, polyoxyethylene glycol-2-ethylhexyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-n-
Stearyl-glycidyl ether, polyoxyethylene glycol-n-stearyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-phenyl-glycidyl ether, polyoxyethylene glycol-phenyl-2,3-dihydroxypropyl ether, polyoxyethylene Glycol-nonylphenyl-
Glycidyl ether, polyoxyethylene glycol-
Nonylphenyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-cyclohexyl-
Glycidyl ether, polyoxyethylene glycol-
Cyclohexyl-2,3-dihydroxypropyl ether, polyoxyethylene / polyoxypropylene glycol copolymer methyl glycidyl ether, polyoxyethylene / polyoxypropylene glycol copolymer methyl-2,3-dihydroxypropyl ether, polyoxy Examples thereof include units derived from n-propyl-2,3-dihydroxypropyl ether of ethylene / polyoxypropylene glycol copolymer, and these units may be contained alone in the copolyester, or Two or more kinds may be contained.

In the copolyester, the total content of the diol unit [b] and the side chain unit [c] is 2 to 40 based on the weight of the copolyester.
It is preferably in the range of 5% by weight, particularly 5 to 30% by weight. When the total content of the diol unit [b] and the side chain unit [c] is less than 2% by weight, the alkali solubility decreases, while when it exceeds 40% by weight, the spinnability becomes difficult.

In addition to the above-mentioned units, the copolymerized polyester includes, for example, triols such as glycerin and trimethylolpropane; tetraols such as pentaerythritol; tricarboxylic acids such as trimellitic acid and trimesic acid; pyromellitic acid and the like. 4 such as tetracarboxylic acid
A small amount of copolymerized units derived from a polyfunctional component such as a polycarboxylic acid having a valency or more may be contained within a range in which melt spinning or melt molding of polyester is possible.

The copolyester has an intrinsic viscosity of 0.5 to 1.5 dl / g, particularly 0.6 to 1.0 dl / g, measured at 30 ° C. in an equal weight mixed solvent of phenol and tetrachloroethane. Is preferable from the viewpoint of processability at the time of spinning.

The copolymerized polyester is a dicarboxylic acid component capable of introducing the above-mentioned units into the copolymerized polyester,
Diol component, side chain unit [c] represented by the above formula [d]
It can be manufactured by carrying out a polycondensation reaction by a conventional method using a compound for use and the like. For example, in the first step, an esterification reaction or transesterification reaction is first carried out using those raw material components to produce a low polymer, and then in the second step the low polymer is subjected to reduced pressure in the presence of a polymerization catalyst. It can be produced by heating to cause polycondensation until the desired degree of polymerization is reached, but of course the method is not limited to this. At that time, in the esterification reaction or transesterification reaction step before the polycondensation reaction, known esterification catalysts and transesterification reaction catalysts used in the production of polyester can be used as necessary.

The island component of the sea-island type composite fiber according to the present invention,
The shape and positional relationship of the sea component in the fiber cross section may be any shape as long as the sea component substantially covers the periphery of the island component. Although a sea-island composite form having a round cross-section is preferable for production, for example, the fiber shape may be any shape such as a square shape, an elliptical shape, and a star shape, or the island component may have any similar shape. Well, the fiber shape and the island shape may be the same or different.

The composite ratio of the sea component and the island component may be set to the optimum composite condition from the viewpoints of the performance of the fiber, the desired heat retaining property, the lightness, the transparency preventing property, the refreshing feeling and the like. Generally, the composite ratio of sea component and island component is sea component / island component = 7/3 to 3/7 (weight ratio), especially sea component / island component = 6/4 to 4/6 (weight ratio) Is preferred. If the proportion of the sea component is too large, a sufficiently large hollow portion cannot be obtained in the treatment with the alkaline aqueous solution, and it is difficult to obtain the desired heat retention property, light weight property, and transparency prevention property. Further, since the permeability of the alkaline aqueous solution into the sea component and the removal of the polyester dissolved and eluted in the alkaline aqueous solution treatment require time and high temperature, the polymer of the sea component is likely to deteriorate. On the other hand, if the ratio of the island component is too large, it becomes difficult to maintain the hollow portion after the polymer of the island component is decomposed and eluted, and the durability in use as a fiber or cloth may be reduced.

The sea-island type composite fiber according to the present invention is usually prepared by using, for example, the above-mentioned copolymerized polyester as the island component and the above-mentioned alkali-resistant polymer as the sea component.
It can be produced by a method such as melt-composite spinning or melt-composite spinning drawing which is adopted when producing the sea-island type conjugate fiber. The sea-island composite fiber produced in this way is
Weaving the fiber as it is, or the composite fiber by a usual method,
It is possible to knit or knit into a fabric, and then to immerse it in an alkaline aqueous solution to decompose and elute almost 100% of the polyester, which is an island component of the composite fiber, to form a porous hollow fiber. In the present invention, an alkali-resistant polymer having a water absorption rate of 3% or more is used as a sea component, and a polyester having a specific alkali dissolution rate constant is used as an island component. Is 1
It is decomposed and eluted by 00% to obtain a completely porous hollow fiber. Since the island component polyester is almost 100% decomposed and eluted, in the porous hollow fiber of the present invention, the variation rate of the cross-sectional area of each of the plurality of hollow portions in the fiber axis direction is very small. Although it is also possible to woven and knit using the porous hollow fiber obtained by the production method of the present invention, in processability, in maintaining the hollow portion of the hollow fiber, etc., after the weaving and knitting, an alkaline aqueous solution treatment is performed to form a porous hollow. It is preferable to make it.

The alkaline aqueous solution treatment is carried out according to the type of alkali,
It is determined by the concentration, the treatment temperature and the treatment time. Generally, when sodium hydroxide is used, the concentration is 10 to 40 g / l and the temperature is 80 in consideration of deterioration of the sea component polymer.
It is preferable to employ -100 ° C. Processing temperature is 10
It does not matter if the temperature exceeds 0 ° C., but in this case, it is preferable to carry out at high pressure. The treatment time is preferably short in terms of the quality of the obtained conjugate fiber or fabric, and the treatment temperature is preferably low.

In the sea-island type composite fiber according to the present invention,
When a polyester obtained by copolymerizing an alkali metal salt of sulfoisophthalic acid is used as the island component polymer, the composite fiber or the cloth is subjected to an acid treatment in advance to perform the above-mentioned alkaline aqueous solution treatment, and the alkali metal salt of sulfoisophthalic acid is added. It is preferable to change to the acid form because the treatment with an alkaline aqueous solution can be easily performed.

The porous hollow fiber of the present invention may have any shape such as a circular shape, a square shape, an elliptical shape, a star shape, etc., or a hollow portion having a similar shape. Often,
The fiber shape and the hollow portion shape may be the same or different. Further, it may have a shape (thick and thin shape) having a thickness unevenness in the fiber axis direction.

The "fibers" referred to in the present invention include long fibers such as monofilaments, short fibers such as staples, filament yarns, spun yarns, natural fibers, semi-synthetic fibers, and mixed fiber yarns with other synthetic fibers. It is a general term for blended yarns, plied yarns, entangled yarns, crimped yarns, and other processed yarns. The “fabric” includes not only woven and knitted fabrics that are woven and knitted with the above-mentioned fibers as a part or all of them, but also non-woven fabrics. ) Excellent, swimwear,
Inner wear-Useful for applications and the like.

[0045]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In addition, each physical property in an Example is a value measured by the following method. (1) Intrinsic viscosity of polyester (dl / g) It is a value measured at 30 ° C. by dissolving a polymer in a tetrachloroethane / phenol mixed solvent (equal weight ratio). (2) Water absorption rate (%) A film having a thickness of 15 µ was prepared from a polymer, the film was immersed in water for 30 minutes or more, and then excess water was wiped off with a filter paper, followed by drying at 105 ° C for 4 hours, followed by the following. It was calculated by the formula. Water absorption rate (%) = {(B−A) / A} × 100 A: Weight after drying at 105 ° C. for 4 hours B: Weight after wiping off excess water with filter paper after immersion in water (3) Sea island Alkaline weight loss rate of type composite fiber (%) A sample knitted using sea-island type composite fiber was treated with an aqueous sodium hydroxide solution at a temperature of 80 ° C. and a concentration of 40 g / l, and the weight before and after the treatment was measured. The weight loss rate was calculated.

(4) Total cross-sectional area (μ ² ) of hollow part and number of hollow part in fiber cross section A scanning electron micrograph (about 2000 to 4000 times) of the cross section of the fiber after the alkaline aqueous solution treatment was taken, and the hollow part was taken. Was counted, and the photograph was copied on paper to calculate the total cross-sectional area of the hollow portion. In the photograph, 5 locations were taken per 1 m of the fiber, and the number of hollow portions and the total cross-sectional area were represented by their average values. (5) Porosity (%) A scanning electron microscope photograph of the cross section of the fiber after the treatment with the alkaline aqueous solution was taken, the photograph was copied on a paper, and the ratio of the hollow portion and the sea portion was calculated by the weight of the paper, and the hollow ratio ( The measured value) was calculated. The sample was taken at 5 locations per 1 m of fiber, and the hollow ratio was calculated from the average value. Next, the hollow ratio (theoretical value) calculated from the composite ratio of sea islands to the hollow ratio (measured value) was determined as the porosity. Porosity (%) = [hollowness ratio (measured value) / hollowness ratio (theoretical value)] × 100 (6) Fiber shedding prevention property (opacity) Single hollow fiber having a denier of 3.1 Used for warps and wefts, with a weaving density of 100 warps / dimension, 90 wefts /
The size of the taffeta was made and the Hitachi spectrophotometer (U-3400
Type) was used to measure the L ^* value of this raw machine, and it was calculated by the following formula. Opacity ^{= (LB * / LA *)} × 100 LA *: White matrix L ^* value when superimposed sample fabric LB ^*: L ^* value (7) when the superposed sample fabric black matrix warmth porous A round neck shirt was produced by knitting a half tricot using a mold hollow fiber, and a heat insulation feeling was evaluated by having 10 panelists wear it. ⊚: 10 out of 10 felt warmth. ◯: 8 out of 10 people felt a warm feeling. Δ: 5 out of 10 felt warmth. X: 3 out of 10 people felt a warm feeling.

Examples 1 to 5 and Comparative Examples 1 to 6 5-sodium sulfoisophthalic acid is 5 mol% with respect to terephthalic acid, polyethylene glycol having a molecular weight of 2000 and a side chain type polyoxyalkylene represented by the following formula. Polyethylene terephthalate copolymerized with 5% by weight of each group-containing compound [alkali solubility constant: 9
0 × 10 ⁻⁸ cm / sec, intrinsic viscosity [η] = 0.53]
Is used as the island component polymer, the polymer shown in Table 1 as the sea component, and the sea-island type composite fiber designed with the number of islands and the island / sea component ratio as shown in Table 1 is spun, and then subjected to ordinary drawing conditions. It was drawn to obtain a drawn yarn of 75 denier / 24 filament.

[0048]

[Chemical 7]

Using this drawn yarn as a warp and a weft,
Taffeta having a weaving density of 100 warps / dimension and 90 wefts / dimension was woven. This raw taffeta was treated with an aqueous solution of 2 g / l of soda ash and 1 g / l of Actinol R-100 (Matsumoto Yushi Co., Ltd.) at 80 ° C. for 30 minutes for scouring. Then, heat set at 140 ° C with a pin tenter, and 40 g /
Using an aqueous solution of sodium hydroxide (1), alkali treatment was performed under the conditions shown in Table 1 to dissolve and remove the island component polymer. The obtained fibers and taffeta made of the fibers were evaluated and measured, and the results are shown in Table 1.

The fibers obtained in Examples 1 to 5 had a satisfactory hollow portion, and the opacity and lightness of the fabric made of the fibers were also satisfactory. The fiber obtained in Comparative Example 1 has a large value represented by the formula [I], the hollow portions are in communication with each other, and the hollow portions (pores) do not become independent porous hollow fibers. Could not be woven due to a decrease in
The fiber obtained in Comparative Example 2 had a small value represented by the formula [I], and the hollow part was crushed in some places, and the opacity was unsatisfactory. Since the fibers obtained in Comparative Examples 3 and 4 each use a polymer having a low water absorption rate as the sea component polymer, the island component polyester is not dissolved and removed by the alkali treatment and may be formed into a hollow fiber. How not to do it. Since the fiber obtained in Comparative Example 5 uses polybutylene terephthalate as the sea component polymer, not only the island component polyester but also the sea component polymer is partially dissolved by the alkali treatment, which is satisfactory. It was not possible to form a simple porous morphology. Since the fiber obtained in Comparative Example 6 had a small value represented by the formula [I], the hollow part was crushed in some places, and the opacity was unsatisfactory.

Examples 6 to 8 and Comparative Examples 7 to 11 In Example 1, the polyester shown in Table 2 was used as the island component polymer, and the sea component / island component ratio was 7/3 (Examples 6, Comparative Examples). 7 to 11) and 1/1 (Examples 7 and 8) except that spinning and drawing were performed to obtain a drawn yarn of 75 denier / 24 filament. Then, using the obtained drawn yarn, a taffeta similar to that in Example 1 was prepared, and scouring treatment, heat setting, and alkali treatment under the treatment conditions shown in Table 3 were performed using a sodium hydroxide aqueous solution having a concentration of 40 g / l. The treatment was carried out to dissolve and remove the island component polymer. The obtained fibers and taffeta made of the fibers were evaluated and measured, and the results are shown in Table 3. Since the fibers obtained in Comparative Examples 7 and 8 have a small solubility constant in the aqueous alkaline solution of the polyester, which is the island component polymer, the polyester cannot be dissolved and removed even when subjected to the alkali treatment, which is satisfactory. It could not be hollow. The fibers obtained in Comparative Examples 9 and 10 use a polymer having a low water absorption rate as the sea component polymer, so that the island component polyester is not dissolved and removed by the alkali treatment and may be formed into a hollow form. How not to do it. Since the fiber obtained in Comparative Example 11 uses polyethylene terephthalate as the sea component polymer, not only the island component polyester but also the sea component polymer is partially dissolved by the alkali treatment, which is satisfactory. It was not possible to form a porous morphology.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

[0055]

EFFECTS OF THE INVENTION The porous hollow fiber of the present invention is superior in lightness and water absorption as compared with the hollow fiber having only one hollow portion, and has a large amount of light reflection. A fabric made of fibers is excellent in preventing sheer.

Claims (2)

[Claims] 1. A porous hollow fiber made of an alkali-resistant polymer having a water absorption rate of 3% or more, wherein the hollow portion in a cross section perpendicular to the fiber axis of the fiber satisfies the following formula [I]. A porous hollow fiber characterized by being. [Equation 1] [However, x is the total cross-sectional area (μ ² ) of the hollow portion, and n is the number of hollow portions and is an integer of 2 or more. ] 2. An alkali dissolution rate constant is 30 × when treated with an alkali resistant polymer having a water absorption rate of 3% or more as a sea component and at a temperature of 80 ° C. and an aqueous sodium hydroxide solution having a concentration of 40 g / l. 10 ^{-8 to} 130 × 10 ^-8 cm / se
A method for producing a porous hollow fiber, comprising spinning a sea-island type composite fiber having a polyester in the range of c as an island component, and then treating it with an alkaline aqueous solution to decompose and elute the island component polyester.