JP2003082531A - Conjugate fiber, hollow fiber and method for producing hollow fiber from the conjugate fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow fiber which has a porous hollow portion and has excellent dyeability, light weight, excellent dry touch, excellent swollen touch and the like without deteriorating light weight, strength and chemical resistance, and to provide a fiber structure containing the fibers. SOLUTION: This sea-island type conjugate fiber contains (I) a polymer composition comprising (II) a polyester-based block copolymer comprising (IIa) a polyester block and (IIb) an addition polymer block as a sea component and (III) a water-soluble thermoplastic polyvinyl alcohol-based polymer as an island component. A method for treating a fiber structure containing the sea- island type conjugate fibers comprises treating the fiber structure with water to dissolve off at least one portion of the water-soluble thermoplastic polyvinyl alcohol-based polymer from the sea-island type conjugate fiber.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a composite fiber, a fiber structure containing the same, a hollow fiber obtained from the composite fiber, and a fiber structure containing the same. More specifically, the present invention relates to a hollow fiber having excellent lightness and dyeability, a dry feeling, and a swelling feeling, and particularly a porous hollow fiber and a fiber structure thereof.

[0002]

2. Description of the Related Art Polyolefin fibers are excellent in lightness,
From strength and chemical resistance, ropes, binding threads, filters,
Widely used for wipers, diapers, sanitary products, etc. Further, due to recent environmental problems, demand is increasing as a material having high recyclability or a material having low combustion heat. However, although polyolefin fibers are lightweight and have excellent chemical resistance, sufficient dyeability is not obtained and they are rarely used for clothing. Further, even when it is used as a non-clothing material such as paper or non-woven fabric, it has not been used in an application field where a delicate color tone is required due to insufficient dyeability. If it is simply a colored polyolefin fiber, it can be obtained as a spun-dyed yarn with a mixture of pigments, but it is difficult to give a subtle shade, and the method of dyeing with a dye has a variety of colors. From the old, many proposals for imparting dyeability to polyolefin fibers have been made. For example, it is a method in which polyester or polyamide having dyeability is mixed or combined with polyolefin to form a fiber. In this case, the dyeability is certainly improved, but peeling and uneven dyeing occur at the interface due to the low adhesiveness between the polyolefin and the polyester or polyamide, which has not been put to practical use. Furthermore, a method of blending or grafting an ethylene / alkyl acrylate copolymer with polypropylene has been proposed (Japanese Patent Publication No. 10-501309).
The dyeability was not fully satisfactory.

On the other hand, synthetic fibers such as polyester and polyamide are widely used not only for clothing but also for industrial use because of their excellent physical and chemical properties including dyeability. It has significant value. However, these synthetic fibers have a single distribution in their single-filament fineness, and have a large single-filament fineness and a simple cross-sectional shape, which makes them natural fibers such as silk, cotton, and hemp. In comparison, the texture and gloss are monotonous, and moreover, it has to be heavier than a fiber material having a specific gravity of less than 1.0 such as polypropylene. Further, the above synthetic fibers were cold, had a slimy feel, and had a low quality. Therefore, in order to improve the above-mentioned drawbacks of the synthetic fiber, it is widely practiced to make the cross-sectional shape of the synthetic fiber irregular or hollow the fiber. Usually, the modified cross-section fiber or hollow fiber produced by using the modified spinning nozzle or hollow spinning nozzle has a modified shape due to the surface tension of the resin in a molten state after spinning and before solidification or the take-up tension during spinning. There is a problem that the cross-section is collapsed or the hollow part is easily crushed, and especially when trying to develop a porous hollow shape, even if the fiber is provided with a porous hollow structure immediately after spinning, the porous hollow part is crushed. Disappeared,
The proportion of the hollow portion is easily reduced, and it is practically impossible to obtain a fiber having a porous hollow portion by such a method. On the other hand, in JP-A-7-316977, an alkali easily decomposable polymer is used as an island component, and as a sea component, an alkali resistant polymer having a water absorption rate of 3% or more such as polyamide or ethylene vinyl alcohol copolymer is used. A technique has been proposed in which, after forming a composite fiber, the easily decomposable polymer is decomposed and removed by treating with a hot alkaline aqueous solution to form a porous hollow fiber. However, as these problems, the wastewater treatment of the alkali decomposition products is complicated, which leaves a big problem from the environmental aspect. Moreover, in such a method, since it is necessary for the alkaline aqueous solution to penetrate the sea component of the composite fiber to extract the island component, it is necessary to use a polymer having water absorbability as the sea component. There were types of restrictions.

[0004]

The object of the present invention is to solve the above-mentioned problems of the prior art and to provide a hollow fiber containing an olefin polymer excellent in lightness, dyeability, dry feeling, swelling feeling and the like. It is to provide a fiber structure containing the fiber. Another object of the present invention is to provide a composite fiber for producing such a hollow fiber without causing wastewater treatment and environmental problems, and further to provide a method for producing a hollow fiber using the composite fiber. .

[0005]

That is, the present invention is directed to a polyester block (IIa) and an addition polymer block (II
5 to 9 of the polyester copolymer (II) consisting of
A composite fiber containing 5% by weight of a polymer composition (I) as a sea component and a water-soluble thermoplastic polyvinyl alcohol polymer (III) as an island component, and a polyester block (IIa) and an addition polymer block. A hollow fiber composed of a polymer composition (I) containing 5 to 95% by weight of a polyester-based copolymer (II) composed of (IIb), the composite fiber being further treated with water. A method for producing a hollow fiber, which comprises dissolving and removing a water-soluble thermoplastic polyvinyl alcohol polymer (III). Furthermore, the present invention is characterized in that the fibrous structure containing the above-mentioned conjugate fiber is treated with water to dissolve and remove the water-soluble thermoplastic polyvinyl alcohol polymer (III) from the conjugate fiber. And a fiber structure containing hollow fibers obtained by such treatment.

The term "fibrous structure" as used in the present invention means, of course, multifilament yarns, spun yarns, woven and knitted fabrics, non-woven fabrics, papers, artificial leathers and filling materials composed of the composite fibers or hollow fibers of the present invention. Thing, natural fiber, semi-synthetic fiber,
Mixed woven and mixed yarns with other synthetic fibers, processed yarns such as plied yarns, entangled yarns and crimped yarns, mixed woven fabrics, knitted fabrics, fiber laminates, and clothing, living materials, industrial materials composed of these ,
It also includes various final products such as medical supplies.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the conjugate fiber of the present invention, a polyester-based copolymer (II) whose sea component is composed of a polyester block (IIa) and an addition polymer block (IIb)
Of a water-soluble thermoplastic polyvinyl alcohol polymer (II
It is important that the composition is composed of I), and if the conditions are satisfied, the form of the sea-island of the composite fiber is not particularly limited. The number of islands may be one or more in the cross section of the composite fiber, but the number of hollow fibers or hollow portions having a high hollow ratio is, for example, 10 or more, further 30 or more, and particularly 50 or more.
The main point of the present invention is exerted in the case of obtaining a hollow fiber having a number of porous hollows. Although the upper limit of the number of islands is not particularly limited, it becomes difficult to fiberize as the number of islands increases, and the fiber physical properties tend to deteriorate, making it difficult to use for applications that require a certain degree of fiber strength. Therefore, it is desired that the number is preferably 1500 or less, more preferably 1000 or less, and further preferably 600 or less, depending on the application. Further, the shape of each island component is not limited at all, and may be circular, elliptical, or any other irregular shape. Furthermore, the island component may be continuous or discontinuous in the fiber axis direction.

Typical examples of the conjugate fiber of the present invention are shown in cross-sectional views, for example, those shown in FIGS. 1 to 6. In the conjugate fiber of FIG. 1, a large island component 2 composed of a water-soluble thermoplastic polyvinyl alcohol polymer (III) in the center of the fiber cross section is a polyester copolymer (II).
Of the polymer composition (I) containing 5 to 95% by weight of the polymer component (I) is surrounded by the sea component 1. The composite fiber in FIG. 2 is a water-soluble thermoplastic polyvinyl alcohol polymer (II
The small island component 2 consisting of I) is in a form surrounded by the sea component 1 consisting of the polymer composition (I) containing 5 to 95% by weight of the polyester copolymer (II), and FIG. In FIG. 2, many smaller island components 2 have irregular shapes that are not circular. In addition, in FIGS. 4 to 6, the fiber cross section has a triangular cross section.

In the present invention, the composite ratio of the island component and the sea component is not particularly limited, but the composite ratio may be appropriately determined depending on the number of hollow portions and the hollow ratio of the finally obtained hollow fiber. Can be changed. However, if the ratio of the island component is too small, the effect such as weight reduction as a hollow fiber is not sufficiently exerted, while if the ratio of the hollow portion is too large, the hollow fiber should have practical fiber properties. It is difficult to do so, preferably island: sea = 2: 98-6
It is preferably 5:35, more preferably 5:95 to 60:40.

The cross-sectional shape of the composite fiber is not particularly limited, and in addition to the circular cross section shown in FIGS. 1 to 3, for example, flat shape, elliptical shape, triangle (FIGS. The square,
It can be any shape such as a T-shape, a multi-leaf shape such as 3 to 8 lobes, and the like. Further, the conjugate fiber of the present invention may contain optional additives such as a fluorescent whitening agent, a stabilizer, a flame retardant and a colorant, if necessary.

The water-soluble thermoplastic polyvinyl alcohol polymer (III) (hereinafter sometimes simply referred to as PVA) used in the present invention is not only a homopolymer of polyvinyl alcohol but also, for example, a copolymer. It also includes a modified polyvinyl alcohol having a functional group introduced by terminal modification, terminal modification, and post-reaction.

The PVA used in the present invention has a viscosity average degree of polymerization (hereinafter simply referred to as a degree of polymerization) of preferably 200 to 500, more preferably 230 to 470, and more preferably 250 to 4
50 is particularly preferred. If the degree of polymerization is less than 200, sufficient spinnability may not be obtained during spinning, and fiber formation may be difficult. If the degree of polymerization exceeds 500, the melt viscosity will be too high,
In some cases, the polymer cannot be discharged from the spinning nozzle. In addition, a so-called low polymerization degree PV having a polymerization degree of 500 or less
By using A, not only the dissolution rate can be increased when the composite fiber is dissolved in the aqueous solution, but also the shrinkage when the composite fiber is dissolved can be reduced.

The degree of polymerization (P) of PVA is JIS-K67.
It is measured according to 26. That is, it is obtained by the following formula from the intrinsic viscosity [η] (dl / g) measured in water at 30 ° C. after re-saponifying PVA and purifying it. P = ([η] × 10 ³ /8.29) ^{(1 / 0.62) When the} degree of polymerization is within the above range, the object of the present invention can be more suitably achieved.

The PVA used in the present invention has a saponification degree of 9
It is preferably from 0 to 99.99 mol%. More preferably 93 to 99.98 mol%, and further 94 to 99.9.
7 mol% is preferable, and 96 to 99.96 mol% is particularly preferable. If the degree of saponification is less than 90 mol%, the thermal stability of PVA may be poor, and satisfactory melt spinning may not be possible due to thermal decomposition or gelation, and the water solubility of PVA may decrease depending on the type of copolymerization monomer described below. There is a case. On the other hand, PVA having a saponification degree of more than 99.99 mol% tends to have low solubility and cannot be stably produced, which makes stable fiber formation difficult.

Further preferred PVA for use in the present invention
Indicates that the molar fraction of the central hydroxyl group of the three-chain hydroxyl group by triad display to the vinyl alcohol unit is 70-
It is preferably 99.9 mol%, has a melting point of 160 ° C. to 230 ° C., and contains 0.0003 to 1 part by mass of alkali metal ion in terms of sodium ion based on 100 parts by mass of PVA.

In the present invention, the central hydroxyl group of the 3-chain hydroxyl group represented by triad display of polyvinyl alcohol means a 500 MHz proton NMR (JEOL GX-500) apparatus in PVA d6-DMSO solution at 65 ° C.
It means a peak (I) reflecting the tacticity of triad of hydroxyl protons measured. Peak (I)
Is the sum of isotacticity chain (4.54 ppm), heterotacticity chain (4.36 ppm) and syndiotacticity chain (4.13 ppm) in the triad of hydroxyl groups of PVA, and all vinyl alcohol units are represented. Since the peak (II) of the hydroxyl group appears in the chemical shift region of 4.05 ppm to 4.70 ppm, the molar fraction of the central hydroxyl group of the 3-chain hydroxyl group by the triad display with respect to the vinyl alcohol unit of the present invention is 100 × (I ) / (II).

Hydroxyl group 3 by PVA triad display
When the content of the central hydroxyl group in the chain is less than 70 mol%, the crystallinity of the polymer is lowered and the fiber strength is lowered, and at the same time, the fibers are stuck to each other during melt spinning and unwinding after winding may occur. is there. Further, the water-soluble thermoplastic fiber intended by the present invention may not be obtained. When the content of the central hydroxyl group of the hydroxyl group 3 chain according to the triad representation of PVA is larger than 99.9 mol%, the melting point of the polymer is high, so that the melt spinning temperature needs to be increased. As a result,
The thermal stability of the polymer during melt spinning is poor, causing decomposition, gelation,
Polymer coloring is likely to occur.

The PVA of the present invention is ethylene-modified P
In the case of VA, the effect of the present invention is further enhanced by satisfying the following formula. -1.5 × Et + 100 ≧ mol fraction ≧≧ -Et + 85 Here, the mole fraction (unit: mol%) represents the mole fraction of the central hydroxyl group of the hydroxyl group 3 chain by the triad notation to the vinyl alcohol unit, and Et is It represents the ethylene content (unit: mol%) contained in the vinyl alcohol polymer.

Therefore, the content of the central hydroxyl group of the 3-chain hydroxyl group by the triad display of PVA used in the present invention is more preferably 72 to 99 mol%, and 74 to 97 mol%.
Is more preferable, and 76 to 95 mol% is particularly preferable.

By controlling the amount of central hydroxyl groups in the 3-chain hydroxyl group of polyvinyl alcohol used in the present invention, various physical properties related to water such as water solubility and hygroscopicity of PVA, strength, elongation, elastic modulus, and other fibers can be obtained. It is possible to control various physical properties related to melt spinning properties such as melting point, melt viscosity and the like. It is considered that this is because the central hydroxyl group of the triad hydroxyl group 3 chain is rich in crystallinity and expresses the features of PVA.

Melting point (Tm) of PVA used in the present invention
Is preferably 160 to 230 ° C., 170 to 2
27 degreeC is more preferable, 175-224 degreeC is further more preferable, 180-220 degreeC is especially preferable. Melting point 160
When the temperature is lower than 0 ° C, the crystallinity of PVA is lowered, the fiber strength of the conjugate fiber is lowered, and at the same time, the thermal stability of the conjugate fiber is deteriorated, and the fiber cannot be formed. On the other hand, the melting point is 2
If it exceeds 30 ° C., the melt spinning temperature becomes high, and the spinning temperature and the decomposition temperature of PVA are close to each other, so that it may not be possible to stably produce a composite fiber composed of PVA and another thermoplastic polymer. The melting point of PVA was measured by using DSC in nitrogen after heating up to 250 ° C. at a heating rate of 10 ° C./min.
It means the temperature at the peak top of the endothermic peak showing the melting point of PVA when cooled to room temperature and heated again to the temperature rising rate of 10 ° C./250° C.

The PVA used in the present invention can be obtained by saponifying vinyl ester units of a vinyl ester polymer. As the vinyl compound monomer for forming the vinyl ester unit, vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate and Examples thereof include vinyl versatate, and of these, vinyl acetate is preferable from the viewpoint of obtaining PVA.

The PVA used in the present invention may be a homopolymer or a modified PVA in which a copolymerized unit is introduced. It is preferable to use a modified polyvinyl alcohol in which a unit is introduced. Examples of the type of copolymerizable monomer include α-olefins such as ethylene, propylene, 1-butene, isobutene, and 1-hexene, acrylic acid and salts thereof, methyl acrylate, ethyl acrylate, and n-acrylic acid. Acrylic esters such as propyl and i-propyl acrylate, methacrylic acid and salts thereof, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate and i-propyl methacrylate, acrylamide, N- Acrylamide derivatives such as methyl acrylamide and N-ethyl acrylamide, methacrylamide derivatives such as methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl Vinyl ether, vinyl ethers such as n- butyl ether, ethylene glycol vinyl ether, 1,3
-Hydroxy group-containing vinyl ethers such as propanediol vinyl ether and 1,4-butanediol vinyl ether, allyl ethers such as allyl acetate, propyl allyl ether, butyl allyl ether, and hexyl allyl ether; monomers having an oxyalkylene group; Vinylsilyls such as vinyltrimethoxysilane, isopropenyl acetate, 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 7-octen-1-ol, 9-decene-1. -Ol, 3-methyl-3-buten-1-ol and other hydroxy group-containing α-olefins, fumaric acid, maleic acid, itaconic acid, maleic anhydride, phthalic anhydride, trimellitic anhydride or itaconic anhydride A monomer having a carboxyl group derived from Nsuruhon acid, allylsulfonic acid, methallyl sulfonic acid, 2-acrylamido-2
Monomers having a sulfonic acid group derived from methylpropanesulfonic acid; vinyloxyethyltrimethylammonium chloride, vinyloxybutyltrimethylammonium chloride, vinyloxyethyldimethylamine, vinyloxymethyldiethylamine, N-acrylamidomethyltrimethylammonium chloride, Examples include monomers having a cationic group derived from N-acrylamidoethyltrimethylammonium chloride, N-acrylamidodimethylamine, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, dimethylallylamine, allylethylamine and the like. The content of these monomers is usually 20 mol% or less.

Among these monomers, α-olefins such as ethylene, propylene, 1-butene, isobutene and 1-hexene, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, Vinyl ethers such as i-propyl vinyl ether and n-butyl vinyl ether, hydroxy group-containing vinyl ethers such as ethylene glycol vinyl ether, 1,3-propanediol vinyl ether and 1,4-butanediol vinyl ether, allyl acetate, propyl allyl ether, butyl Allyl ether,
Allyl ethers such as hexyl allyl ether, monomers having an oxyalkylene group, 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 7-octen-1-ol, Monomers derived from hydroxy group-containing α-olefins such as 9-decen-1-ol and 3-methyl-3-buten-1-ol are preferred.

In particular, ethylene, propylene, 1-butene, from the viewpoint of copolymerizability, melt spinnability and water solubility of fibers,
More preferred are α-olefins having 4 or less carbon atoms of isobutene, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether and n-butyl vinyl ether. The unit derived from α-olefins and / or vinyl ethers having 4 or less carbon atoms is 0.1 to 0.1% in PVA.
20 mol% is preferably present, more preferably 1 to 20 mol%, further preferably 4 to 15 mol%,
6 to 13 mol% is particularly preferable. Further, when the α-olefin is ethylene, the physical properties of the fiber become high, so it is preferable to use a modified PVA in which an ethylene unit is introduced in an amount of 4 to 15 mol%, more preferably 6 to 13 mol%.

Examples of the PVA used in the present invention include known methods such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method and an emulsion polymerization method. Among them, a bulk polymerization method or a solution polymerization method in which polymerization is carried out without solvent or in a solvent such as alcohol is usually adopted. Examples of the alcohol used as the solvent during the solution polymerization include lower alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol. As the initiator used for the copolymerization, α, α′-azobisisobutyronitrile, 2,2′-azobis (2,2
4-dimethyl-valeronitrile), benzoyl peroxide,
Known initiators such as azo-based initiators such as n-propyl peroxycarbonate or peroxide-based initiators may be mentioned. The polymerization temperature is not particularly limited, but is 0 ° C to 1
A range of 50 ° C is suitable.

The content ratio of the alkali metal ion in the PVA used in the present invention is preferably 0.0003 to 1 part by mass, and 0.0003 to 0.8 part by mass in terms of sodium ion based on 100 parts by mass of PVA. A part is more preferable, 0.0005 to 0.6 part by mass is further preferable, and 0.0005 to 0.5 part by mass is particularly preferable. When the content ratio of the alkali metal ion is less than 0.0003 parts by mass, sufficient water solubility may not be exhibited and undissolved matter may remain. Further, when the content of alkali metal ions is more than 1 part by mass, decomposition and gelation during melt spinning may be remarkable and fiber formation may not be possible. Examples of alkali metal ions include potassium ion and sodium ion.

In the present invention, the method of incorporating a specific amount of alkali metal ions into PVA is not particularly limited, and P
A method of adding an alkali metal ion-containing compound after polymerizing VA, and when saponifying a vinyl ester polymer in a solvent, by using an alkaline substance containing an alkali ion as a saponification catalyst, an alkali metal ion is added to PVA. PVA obtained by blending and saponifying
Examples of the method include controlling the content of alkali metal ions contained in PVA by washing the above with a washing liquid, but the latter is preferable. The content of alkali metal ions can be determined by the atomic absorption method.

Examples of the alkaline substance used as the saponification catalyst include potassium hydroxide and sodium hydroxide. The molar ratio of the alkaline substance used in the saponification catalyst is preferably 0.004 to 0.5, and particularly preferably 0.005 to 0.05, based on the vinyl acetate unit. The saponification catalyst may be added all at once at the beginning of the saponification reaction, or may be additionally added during the saponification reaction. As the solvent for the saponification reaction, methanol, methyl acetate, dimethyl sulfoxide,
Examples include dimethylformamide. Among these solvents, methanol is preferable, and the water content is 0.001 to
Methanol controlled to 1 mass% is more preferable, methanol whose water content is controlled to 0.003 to 0.9 mass% is more preferable, and methanol whose water content is controlled to 0.005 to 0.8 mass% is particularly preferable. . Examples of the washing liquid include methanol, acetone, methyl acetate, ethyl acetate, hexane, water and the like, and among these, methanol, methyl acetate, water alone or a mixed liquid is more preferable. The amount of the cleaning liquid is set so as to satisfy the content ratio of the alkali metal ions, but normally 300 to 10,000 parts by mass is preferable with respect to 100 parts by mass of PVA, and 500.
〜5000 parts by mass is more preferred. As the cleaning temperature,
5-80 degreeC is preferable and 20-70 degreeC is more preferable.
The washing time is preferably 20 minutes to 10 hours, more preferably 1 hour to 6 hours.

Further, in the present invention, P as described above is used.
Even if VA is used, PVA is generally inferior in melt fluidity at high temperature as compared with a general-purpose thermoplastic resin, and therefore, if necessary, polyethylene glycol, propylene glycol and its oligomer, butylene glycol and its Oligomer, polyglycerin derivative, glycerin derivative in which alkylene oxide such as ethylene oxide and propylene oxide is added to glycerin, derivative in which alkylene oxide such as ethylene oxide and propylene oxide is added to sorbitol, polyhydric alcohol such as pentaerythritol and its derivative , PO /
It is preferable to add a plasticizer such as an EO random copolymer to PVA at a ratio of 1 to 30% by mass, preferably 2 to 20% by mass, from the viewpoint of improving the spinnability. Then, in order to obtain good plasticization and spinnability, thermal decomposition hardly occurs in the fiberizing step, in order to obtain an alkylene oxide adduct of sorbitol,
Polyglycerin alkyl monocarboxylic acid ester, PO
It is preferable to add 1 to 30% by mass, preferably 2 to 20% by mass of a plasticizer such as / EO random copolymer, and particularly 1 to 30% of sorbitol ethylene oxide.
Compounds with a mole addition are preferred.

In the polymer composition (I) constituting the sea component of the conjugate fiber of the present invention, typical examples of the residual thermoplastic polymer component blended with the above-mentioned polyester copolymer (II) are: For example, an olefin homopolymer [hereinafter sometimes referred to as an olefin homopolymer ()]; a copolymer composed of ethylene and another α-olefin and having ethylene as a main component [hereinafter, ethylene / α-olefin copolymer Copolymer (may be referred to as ()]; a copolymer composed of propylene and another α-olefin and containing propylene as a main component [hereinafter, sometimes referred to as propylene / α-olefin copolymer ()]; hydrogenated conjugation Examples thereof include a diene copolymer [hereinafter sometimes referred to as a hydrogenated conjugated diene copolymer ()].

Specific examples of the above-mentioned olefin homopolymer () include low density, medium density, high density polyethylene, polypropylene, polybutene-1, polyhexene-
1, homopolymers of olefins such as poly-3-methyl-butene-1, poly-4-methyl-pentene-1, etc., among which low density, medium density, high density polyethylene and / or polypropylene can be mentioned. Are preferably used in terms of fiber characteristics (strength, elastic modulus) and the like.

The ethylene / α-olefin copolymer () is mainly composed of ethylene and an α-olefin having 3 to 20 carbon atoms (eg propylene, 1
-Butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 3-methyl-1-butene, 4-methyl-1-pentene, 6-methyl-1-heptene, isooctene, iso Copolymers with one or two or more of octadiene and decadiene). Among them, ethylene, propylene, 1-
Butene, 1-pentene, 1-hexene, 1-heptene,
A copolymer with one or more olefins having 1 to 10 carbon atoms such as 1-octene and 1-decene is preferably used. The mass ratio of ethylene: α-olefin in the ethylene / α-olefin copolymer () is preferably in the range of 50:50 to 98: 2, from 60:40 to 90:10, from the viewpoint of fiber characteristics. It is more preferable. Also, ethylene / α-olefin copolymer ()
May have a diene unit together with an ethylene unit and an α-olefin unit, and examples of such a copolymer include an ethylene / propylene / diene copolymer (EPD).
M) etc. can be mentioned.

As the propylene / α-olefin copolymer (), propylene / ethylene block copolymer and other propylene and ethylene and / or the above-mentioned carbon number of 4 to 20, especially 4 to 10 are mentioned. And a copolymer with α-olefin.

As the hydrogenated conjugated diene copolymer (), [i] a polymer block mainly composed of an aromatic vinyl compound such as styrene and a hydrogenated 1,2-bond amount are typically used. At least one polymer block selected from polybutadiene blocks of less than 30 mol%, hydrogenated polyisoprene blocks, polybutadiene blocks having a hydrogenated 1,2-bond content of 30 to 80 mol% and hydrogenated polyisoprene blocks. Block copolymer composed of at least one polymer block selected from isoprene / butadiene copolymer blocks; and [ii] a block composed mainly of a polymer block composed of an aromatic vinyl compound and a hydrogenated polyisobutylene block. Copolymers; by using these block copolymers Good.

Specific examples of the block copolymer [i] include hydrogenated products of block copolymers of polystyrene / polyisoprene / polystyrene; blocks of polystyrene / isoprene / butadiene copolymer / polystyrene. A hydrogenated product of a copolymer; a hydrogenated product of a block copolymer composed of polystyrene / polybutadiene / polystyrene can be mentioned.

In the present invention, one kind of the above-mentioned olefinic polymers to may be used alone, or two or more kinds may be used in combination. Further, a small amount of other synthetic resin or rubber may be used together with the above-mentioned olefin polymer within a range not hindering the object of the present invention.

Further, in the present invention, the ratio (Mw / Mn) of the mass average molecular weight (Mw) to the number average molecular weight (Mn) of the olefin polymer is 4 or less, more preferably 3.5 or less. It is preferable to use one in terms of fiber characteristics. The ratio (Mw / Mn) of the mass average molecular weight (Mw) to the number average molecular weight (Mn) in the present invention is the gel permeation chromatography (GPC) [for GPC] using polystyrene having a known molecular weight as a standard substance. apparatus:
WATERS "150C", column: "Shode
x AT-807 / S "and" Shodex AT-80
MIS "(manufactured by Showa Denko KK), column temperature: 140 ° C, sample concentration: 0.1% by mass, solvent: o-dichlorobenzene]
It was obtained by.

The ratio (Mw) of the mass average molecular weight (Mw) and the number average molecular weight (Mn) preferably used in the present invention.
/ Mn) is 4 or less, the production method of the olefin-based polymer is not limited at all, and the commercially available olefin-based polymer having the ratio (Mw / Mn) of 4 or less can be used as it is or produced by polymerization. You may use. The olefin-based polymer having a ratio (Mw / Mn) of 4 or less includes, for example, a metallocene catalyst (also referred to as a Kaminsky catalyst or a single-site catalyst) as a polymerization catalyst, although not limited thereto. By using a solution polymerization method, a bulk polymerization method, a gas phase polymerization method, or the like, usually at a temperature of 0 to 250 ° C. and normal pressure to
It can be obtained by polymerizing a monomer under a pressure of 1000 atm (100 MPa). As the metallocene catalyst, for example, a combination of a metallocene compound containing a tetravalent transition metal and methylaluminoxane and / or a non-coordinating boron compound is used. The use ratio thereof is generally 2 to 1,000,000 mol of methylaluminoxane and / or non-coordinating boron-based compound, preferably 50 to 5, with respect to 1 mol of the metallocene compound.
It is 000 mol.

Examples of the above metallocene compound include cyclopentadienyl titanium tris (dimethylamide), methylcyclopentadienyl titanium tris (dimethylamide), and bis (cyclopentadienyl).
Titanium dichloride, dimethylsilyltetramethylcyclopentadienyl-t-butylamide zirconium dichloride, dimethylsilyltetramethylcyclopentadienyl-t-butylamide hafnium dichloride, dimethylsilyltetramethylcyclopentadienyl-pn
-Butylphenylamide zirconium chloride, methylphenylsilyl tetramethylcyclopentadienyl-t
-Butylamido hafnium dichloride, (t-butylamido) (tetramethylcyclopentadienyl) -1,2
-Ethanediyl titanium dichloride, indenyl titanium tris (dimethyl amide), indenyl titanium tris (diethyl amide), indenyl titanium bis (di-n-butyl amide) (di-n-propyl amide)
Etc. can be used.

The melt index (hereinafter sometimes referred to as "MI") of the olefin polymer used in the present invention is 0.1 from the viewpoint of improving the properties of the obtained fiber and the processability of fiber formation. It is preferably in the range of -50 g / 10 minutes, more preferably in the range of 0.1-30 g / 10 minutes, and even more preferably in the range of 0.1-15 g / 10 minutes. The MI of the olefin polymer referred to in the present invention is in accordance with JIS K7210,
A value when measured under the conditions of 190 ° C. and a load of 2.16 kg.

Further, the specific gravity of the olefin polymer used in the present invention is preferably in the range of 0.86 to 0.92, more preferably in the range of 0.86 to 0.90.

Next, the polyester copolymer (II) used in the present invention is derived from a polyester block (IIa) derived from a polyester resin and an addition polymer having a functional group capable of reacting with the polyester resin. Which is a copolymer composed of an addition polymer block (IIb) and a polyester-based copolymer (II), the polyester block (IIa) and the addition polymer block (IIb) described above.
And are bound by a chemical bond such as an ester bond, an amide bond and an ether bond. The polyester-based copolymer (II) is a block copolymer in which the polyester block (IIa) and the addition polymer block (IIb) are bonded in a block form,
It may be a graft copolymer in which a) and the addition polymer block (IIb) are bonded in a graft form, or a copolymer in which both a block-like bond form and a graft-like bond form are present. Good.

The polyester copolymer (II) comprises a polyester block (IIa) and an addition polymer block (IIb).
When and are block copolymers in which blocks are bonded, for example, one polyester block (IIa)
And a diblock copolymer in which one addition polymer block (IIb) is bonded, and one polyester block (II
a triblock copolymer in which one addition polymer block (IIb) is bonded to both sides of the a), and 1)
A triblock copolymer, a polyester block (II), in which one addition polymer block (IIb) is sandwiched and one polyester block (IIa) is bonded on each side
Examples thereof include a polyblock copolymer in which a) and the addition polymer block (IIb) are alternately bonded in a total of four or more.

The polyester-based copolymer (II) is
In the case of a graft copolymer in which the polyester block (IIa) and the addition polymer block (IIb) are bound in a graft form, for example, the polyester block (IIa) is the main chain and the addition polymer block (IIb) is a side chain. Graft copolymer having one or two or more chains as a chain, addition polymer block (IIb) as a main chain and polyester block (IIa) as one or two side chains
Examples thereof include a graft copolymer in which at least one is bonded.

Among the above, the polyester copolymer (II) is composed of one polyester block (IIa) and one addition polymer block ( It is preferred that IIb) is a block-bound diblock copolymer.

The polyester block (IIa) forming a part of the polyester copolymer (II) can be formed from various polyesters, for example, polyethylene terephthalate, polytrimethylene terephthalate,
Polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, poly-1,4-cyclohexane dimethylene terephthalate, polycaprolactone, polylactic acid, p
Examples thereof include blocks formed from hydroxybenzoic acid-based polyester, polyarylate, and the like.

Among the above polyesters, it is preferable to use at least one of polyethylene terephthalate and polybutylene terephthalate, and it is particularly preferable to use polybutylene terephthalate (PBT).

The polyester is a dicarboxylic acid unit other than the dicarboxylic acid unit constituting the basic structure, and / or a diol unit constituting the basic structure, if necessary, if it is 20 mol% or less based on the total structural units. It may have other diol units other than. Examples of other dicarboxylic acid units that the polyester may contain include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,
5-naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4 '
-Aromatic dicarboxylic acids such as diphenyl ether dicarboxylic acid and sodium 5-sulfoisophthalate; Aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid and dodecanedioic acid; 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane Examples thereof include alicyclic dicarboxylic acids such as dicarboxylic acids; and dicarboxylic acid units derived from their ester-forming derivatives (lower alkyl esters such as methyl ester and ethyl ester). The polyester may have only one type of the above dicarboxylic acid units, or may have two or more types.

Examples of other diol units which the polyester may contain include aliphatic groups having 2 to 10 carbon atoms such as ethylene glycol, propylene glycol, neopentyl glycol, 2-methylpropanediol and 1,5-pentanediol. Diols; alicyclic diols such as cyclohexanedimethanol and cyclohexanediol; diethylene glycol, polyethylene glycol, poly-
Examples thereof include diol units derived from polyalkylene glycol having a molecular weight of 6000 or less such as 1,3-propylene glycol and polytetramethylene glycol. The polyester may have only one type of the above diol units, or may have two or more types.

Further, the polyester is derived from trifunctional or higher functional monomers such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, and pyromellitic acid as long as it is 1 mol% or less based on all structural units. It may have a structural unit.

Further, the block (IIa) composed of such a polyester is the quality of the polyolefin fiber of the present invention,
From the viewpoint of dyeability, the number average molecular weight is 200 to 150,000.
Is preferable, and more preferably 200 to 50,000.

The addition polymer block (IIb) forming another part of the polyester copolymer (II) may be any block composed of an addition polymer, and its polymerization form is not particularly limited. Not done. The addition polymer block (IIb) includes any of an addition polymer composed of a single addition polymerizable monomer, a random copolymer composed of a plurality of addition polymerizable monomers, and a block copolymer composed of a plurality of polymerizable monomers. It may be formed from an addition polymer.
Among them, the addition polymer block (IIb) in the polyester copolymer (II) is a polymer block (a1) mainly composed of an aromatic vinyl compound unit [hereinafter, referred to as "polymer block (a1)". And a polybutadiene block (a2) having a hydrogenated 1,2-bond content of less than 30% [hereinafter, this may be referred to as "hydrogenated polybutadiene block (a2)"]. The combined block (A) and the hydrogenated polyisoprene block (b1) [hereinafter, this may be referred to as "hydrogenated polyisoprene block (b1)"], and the hydrogenated 1,2-bond content is 30 to 80
% Polybutadiene block (b2) [hereinafter sometimes referred to as "hydrogenated polybutadiene block (b2)"] and hydrogenated isoprene / butadiene copolymer block (b3) [hereinafter referred to as "hydrogenated isoprene /
Sometimes referred to as "butadiene block (b3)"] and an addition polymerization block copolymer (II) containing at least one polymer block (B) selected from the group consisting of
b1); and an addition consisting of a polymer block (C) mainly composed of an aromatic vinyl compound unit [hereinafter, this may be referred to as an "aromatic vinyl polymer block (C)"] and a polyisobutylene block (D). It is preferably an addition polymer block derived from at least one of the polymerization block copolymer (IIb2).

An addition polymer block (IIb1) comprising the polymer block (A) and the polymer block (B)
As an example of the block structure of, the following general formula (1)-
The thing represented by (4) can be mentioned.

(AB) e (1) (BA) f (2) A- (BA ') g (3) B'-(AB) h (4) [in the above formula, A and A ′ each represent a polymer block (A), B and B ′ each represent a polymer block (B), and e, f, g and h each independently represent an integer of 1 or more. ]

Repetition numbers e, f, g in the addition polymer block (IIb1) represented by the above general formulas (1) to (4).
And h can be arbitrarily determined, but 1 to
It is preferably an integer within the range of 5.

The addition polymer block (IIb1)
Is the above general formula (1) among the addition polymer blocks (IIb1) represented by the above general formulas (1) to (4).
Where e = 1 and the addition polymerization system diblock represented by the formula AB or the addition polymerization system triblock represented by the formula: ABA ′ where g = 1 in the above general formula (3). More preferably, it is a block.

As an example of the block structure of the addition polymer block (IIb2) comprising the aromatic vinyl polymer block (C) and the polyisobutylene block (D), which can form the addition polymer block (IIb), Examples thereof include those represented by the following general formula (5) or (6).

C- (D-C ') j (5) D'-(C-D) k (6) [In the above formula, C and C'each represent an aromatic vinyl polymer block (C), D and D ′ each represent a polyisobutylene block (D), and j and k each independently represent an integer of 1 or more].

Although j and k in the addition polymer block (IIb2) represented by the above general formula (5) or (6) can be arbitrarily determined, they are integers within the range of 1 to 5. Is preferred. The addition polymer block (II) represented by the above general formula (5) or (6) is
b2), in the above general formula (5), j = 1
Is an addition polymerization type triblock represented by the formula: C-D-C 'or a formula in which k = 1 in the above general formula (6):
More preferably, it is an addition polymerization type triblock represented by D′-CD.

In the polymer block (a1) that may form the addition polymer block (IIb1) and the aromatic vinyl polymer block (C) that may form the addition polymer block (IIb2), As an aromatic vinyl compound forming an aromatic vinyl unit in the polymer block of styrene, styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, Vinyl anthracene and the like can be mentioned, and among them, styrene and α-methylstyrene are preferable from the viewpoint that the fiberizing processability of the polyolefin-based fiber becomes better,
Styrene is especially preferred. The polymer block (a1) and the aromatic vinyl polymer block (C) may be composed of one kind of aromatic vinyl compound unit or may be composed of two or more kinds of aromatic vinyl compound unit. .

The hydrogenated polybutadiene block (a2) which can be a constituent block of the polymer block (A) in the addition polymer block (IIb2) has a 1,2-bond content of less than 30% in the polybutadiene block. Is preferable and 25% or less is more preferable.
At the same time, it is preferable that the hydrogenated polybutadiene block (a2) is a polybutadiene block in which a part or all, preferably 90% or more, of unsaturated bonds are saturated by addition of water. Further, in the polybutadiene constituting the hydrogenated polybutadiene block (a2), before hydrogenation, preferably less than 30 mol%, more preferably 25 mol% or less of the vinyl ethylene group [-CH (CH
= CH ₂ ) -CH _2- ; 1,2-bond butadiene unit]
And the rest is a 2-butene-1,4-diyl group (-CH
_{2 -CH = CH-CH 2 -} ; 1,4-bonded butadiene unit).

The hydrogenated polyisoprene block (b1), which can be a constituent block of the polymer block (B) in the addition polymer block (IIb1), is a polyisoprene unsaturated bond mainly composed of monomer units derived from isoprene. It is preferably a polymer block which is partially or wholly hydrogenated to be a saturated bond. In the hydrogenated polyisoprene block (b1), the unit derived from isoprene is 2-methyl-2 before the hydrogenation.
- butene-1,4-diyl group _{[-CH 2 -C (CH 3)} =
CH-CH ₂ -; 1,4- bond of isoprene unit], isopropenyl ethylene group _{[-CH {-C (CH 3)} = C
H _2} -CH ₂ -; 3,4- bond of isoprene units] and 1-methyl-1-vinyl ethylene group [-C (CH ₃₎
(CH═CH ₂ ) —CH ₂ —; 1,2-bond isoprene unit] is preferred.

The hydrogenated polybutadiene block (b2) which can be a constituent block of the polymer block (B) in the addition polymer block (IIb1) preferably has a 1,2-bond amount of 30 to 80 in the polybutadiene block.
%, More preferably 35 to 60%, and a polybutadiene block in which some or all of unsaturated bonds are saturated by hydrogenation is preferable.
The polybutadiene constituting the hydrogenated polybutadiene block (b2) is preferably 30 to 8 before hydrogenation.
0 mol%, more preferably 35 to 60 mol% is a vinyl ethylene group [—CH (CH═CH ₂ ) —CH ₂ —; 1,2-
Butadiene unit of bond], preferably 70 to 20
Mol%, more preferably 65 to 40 mol% of 2-butene-1,4-diyl group _{(-CH 2 -CH = CH-CH} 2 -;
1,4-bond butadiene unit).

Further, a hydrogenated isoprene / butadiene copolymer block (b3) which can be a constituent block of the polymer block (B) in the addition polymer block (IIb1).
Is an isoprene / butadiene copolymer mainly composed of a unit derived from isoprene and a unit derived from butadiene, and a copolymerization unit in which some or all of unsaturated bonds thereof are saturated bonds by hydrogenation. It is a united block. In the hydrogenated isoprene / butadiene copolymer block (b3), the unit derived from isoprene is 2-methyl-2-butene-before hydrogenation.
1,4-diyl group, isopropenylethylene group and 1
-Methyl-1-vinylethylene group is at least one group selected from the group consisting of vinylethylene group and / or 2-butene-
It is preferably a 1,4-diyl group. The ratio of those groups in the isoprene / butadiene copolymer block before hydrogenation is not particularly limited. Also,
Hydrogenated isoprene / butadiene copolymer block (b3)
In the above, the units derived from butadiene and the units derived from isoprene may be arranged in any of a random shape, a block shape, and a tapered block shape.

Then, a hydrogenated polybutadiene block (a2), a hydrogenated polyisoprene block (b1), a hydrogenated polybutadiene block (b2) and a hydrogenated isoprene / which can be a constituent block of the addition polymer block (IIb1)
In the butadiene copolymer block (b3), as described above, some or all of the carbon-carbon double bonds may be hydrogenated, but addition polymers may be used. In the block (IIb1), 50 mol% or more, particularly 80 mol% or more, of carbon-carbon double bonds in the butadiene unit and / or the isoprene unit are hydrogenated (that is, the degree of unsaturation is 50 mol% or less, In particular, when it is 20 mol% or less), the polyester copolymer (II) has good heat deterioration resistance and weather resistance, and prevents deterioration of the fiberizing processability of the polyolefin fiber obtained by using the polyester copolymer (II). It is preferable in that it can be done.

[0067] Also, polyisobutylene block in addition polymer block (IIb2) (D), the isobutylene units _{[-C (CH 3) 2 -CH} 2 -] is predominantly made polymer block from.

{Total content of polymer block (A)} in addition polymer block (IIb1): {total content of polymer block (B)}, and {aromatic vinyl in addition polymer block (IIb2) The total content of the polymer block (C)}: {the total content of the polyisobutylene block (D)} is in the range of 1: 9 to 9: 1 (mass ratio), respectively, and the fiber of the polyolefin fiber is It is preferable from the viewpoint of improving the chemical conversion processability, and each is more preferably 2: 8 to 7: 3 (mass ratio).

Further, the polymer block (A) in the addition polymer block (IIb1) and the aromatic vinyl polymer block (C) in the addition polymer block (IIb2).
Has a number average molecular weight of 1,000 to 100,
000 is preferable, and the range of 2500 to 50,000 is more preferable. In addition, addition polymer block (II
The number average molecular weights of the polymer block (B) in b1) and the polyisobutylene block (D) in the addition polymer block (IIb2) are 1,000 to 100, respectively.
It is preferably in the range of 000. And an addition polymer block (IIb1) and an addition polymer block (IIb2)
Has a number average molecular weight of 12,500 to 150,000.
It is preferably within the range. In addition, in the polyester resin composition of the present invention, even if one or two or more addition polymer blocks (IIb1) are used, one or two or more addition polymer blocks (IIb2) are used. May be.

Then, the polyester block (IIa) and the addition polymer block (II) used in the composite fiber of the present invention are used.
The number average molecular weight of the polyester-based copolymer (II) consisting of b) is preferably in the range of 12700 to 300,000, more preferably in the range of 15,000 to 200,000.

The method for producing the polyester copolymer (II) used in the conjugate fiber of the present invention is not particularly limited. Polyester copolymer (II) from the resulting polyester reaction product, which is obtained by kneading the coalesced product with the coalescence under melting conditions, followed by solid phase polymerization.
Can be obtained by extracting and collecting.

At this time, the melt-kneading of the polyester resin and the addition polymer can be carried out by using a melt-kneading device such as a single-screw extruder, a twin-screw extruder, a kneader or a Banbury mixer. The melt-kneading conditions can be appropriately selected according to the type of polyester resin or addition polymer to be used, the type of equipment, etc., but usually 180 to 300
It may be carried out at a temperature of ℃ for about 3 to 15 minutes. The solid-phase polymerization after melt-kneading is performed by solidifying and granulating a resin obtained by melt-kneading a polyester resin and an addition polymer, and then transferring it to an appropriate solid-state polymerization reaction device for pretreatment. Can be performed by performing drying or crystallization at a temperature of 120 to 180 ° C., and then performing solid phase polymerization. The solid phase polymerization reaction is usually carried out under an inert gas flow or in vacuum while maintaining the temperature of the resin at a temperature about 5 to 60 ° C. lower than the melting point of the polyester resin. Solid phase polymerization may be carried out in either a batch system or a continuous system,
A desired degree of polymerization and a desired reaction rate can be obtained by appropriately adjusting the residence time and the treatment temperature in the solid-state polymerization reactor.

In the above, the extraction and recovery of the polyester copolymer (II) from the polyester reaction product obtained by solid phase polymerization is carried out by, for example, dissolving the polyester reaction product in a hexafluoroisopropanol / chloroform mixed solvent. Then, the solution is poured into tetrahydrofuran to cause precipitation, the precipitate is recovered and dissolved in chloroform, insoluble matter is removed from the chloroform solution by filtration, etc., and the chloroform solution is concentrated and dried to dryness to produce polyester. It can be carried out by a method of collecting the system copolymer (II) as a solid content.

As the addition polymer having a functional group capable of reacting with the polyester resin, which is used for producing the polyester copolymer (II) [reaction product containing the polyester copolymer (II)], Addition polymer block (II
An addition polymer having a structure having a functional group in b) is preferably used. The functional group in that case is not particularly limited as long as it is a functional group capable of reacting with a polyester resin,
For example, a hydroxyl group, a carboxyl group, an ester group, an amide group, an amino group, an epoxy group, a thiol group, a thioester group, a cyclic iminoether group such as a 2-oxazoline group,
Examples thereof include a group having an acid anhydride structure such as a succinic anhydride-2-yl group and a succinic anhydride-2,3-diyl group. Examples of the addition polymer having these functional groups include copolymerization of a monomer having no functional group and a monomer having a functional group, addition reaction of a monomer having a functional group to an addition polymer having an active terminal, and functional group. It can be produced by a radical reaction or the like between a monomer having a group and an addition polymer.

In the addition polymer having a functional group capable of reacting with the polyester resin, the functional group may be located in the middle of the main chain or side chain of the addition polymer or at the end of the molecule. Is a polyester-based copolymer (I
The preferred block form of I) is one polyester block (IIa) and one addition polymer block (II
In order to form a diblock type polyester-based copolymer (II) in which b) is linked in a chain form, it is preferable that the addition polymer has a functional group at the terminal. In addition, the content of the functional group in the addition polymer is preferably 0.5 or more, and more preferably 0.7 or more, per molecule on average.

The fiber of the present invention must contain 5 to 95% by weight of the above block copolymer (II). When the content of the block copolymer is less than 5% by weight, the lightness and the sufficient dyeability which are the features of the present invention cannot be achieved at the same time. Further, the block copolymer is 95% by weight.
If the content exceeds the above range, the spinnability is deteriorated and it is difficult to obtain fibers having practical strength.

The conjugate fiber of the present invention is made of PVA as described above.
Of the polymer composition (I) containing 5 to 95% by weight of the polyester copolymer (II) consisting of the polyester block (IIa) and the addition polymer block (IIb) as the sea component. It is not particularly limited as long as it is a spinning technique capable of forming a polymer, and in a system of a combination of a polymer that reacts with PVA of an island component at the time of heat melting and does not gel, for example, a method by mixed spinning is possible, and the island component And a polymer composition (I) as a sea component,
It can be melt-kneaded by one extruder and then discharged from the same spinning nozzle to be wound and fiberized.
In the method of composite spinning, PVA and the polymer composition (I) are melt-kneaded by different extruders, respectively, and then PVA becomes an island component to form a polyester-based copolymer.
The polymer composition (I) containing 5 to 95% by weight of (I) can be discharged from a sea-island type composite spinning nozzle so as to be a sea component, and wound up to form a fiber.

The fiberizing conditions need to be set according to the combination of polymers and the cross-sectional shape of the composite. (1) Generally, PVA is a polymer that is inferior in melt fluidity at high temperature and self-crosslinks in the presence of a retention part and easily gels. Therefore, as much as possible, an extrusion zone of a polymer and a jet pack (assembly of composite spinning parts) It is important to make it difficult for the retention part to occur in the polymer fluidized part inside the body. (2) The spinneret temperature is Mp to Mp + 80, where Mp is the melting point of the polymer having the highest melting point among the polymers constituting the composite fiber.
℃ is preferable, shear rate (γ) 1,000 to 25,000 sec ^-1 ,
It is preferable to carry out spinning with a draft V10 to 500. (3) From the viewpoint of the combination of the polymers to be composited, it is possible to improve the spinning stability by combining the polymers whose melt viscosities are close to each other when measured by the spinneret temperature during spinning and the shear rate when passing through the nozzle. It is preferable from the aspect.

The melting point Tm of PVA in the present invention is the peak temperature of the main endothermic peak observed with a differential scanning calorimeter (DSC: TA3000 manufactured by Mettler). The shear rate (γ) is calculated by γ = 4Q / πr ³ when the nozzle radius is r (cm) and the polymer discharge amount per single hole is Q (cm ³ / sec). Further, the draft V is calculated by V = 5A · πr ² / 3Q when the take-up speed is A (m / min).

In producing the conjugate fiber of the present invention, if the spinneret temperature is lower than the melting point Tm of PVA, the PV
A cannot be spun because A does not melt. On the other hand, when the temperature exceeds Tm + 80 ° C., PVA is apt to cause thermal decomposition or gelation due to self-crosslinking, resulting in deterioration of spinnability. If the shear rate is lower than 1,000 sec ^-1 , thread breakage will occur easily,
If it is higher than 00 sec ^-1, the back pressure of the nozzle becomes high and the spinnability deteriorates. When the draft is lower than 10, the fineness unevenness becomes large and it becomes difficult to spin stably, and when the draft is higher than 500, the yarn is easily broken.

The yarn discharged from the spinning nozzle is wound at high speed without stretching or is stretched as necessary without stretching.
Stretching is performed at a temperature equal to or higher than the glass transition point (Tg) at a breaking elongation (HDmax) × 0.55 to 0.9 times. Draw ratio is HD
If it is less than max × 0.55, a composite fiber having sufficient strength cannot be obtained stably, and if it exceeds HDmax × 0.9, yarn breakage tends to occur. Stretching may be carried out after being once wound after being discharged from the spinning nozzle, or may be carried out subsequent to the stretching. In the present invention, either may be adopted. Stretching is usually hot stretching and may be performed using any of hot air, hot plate, hot roller, water bath and the like. In the drawing step, the larger the absolute value of the draw ratio, the more easily fluffing and fiber breakage occur. Therefore, it is preferable to use the high-speed spinning to low-draw ratio fiberization conditions or the known high-speed spinning / winding only method.

The drawing temperature is appropriately set according to the composite polymer of the composite, but since the polyvinyl alcohol used in the present invention has a high crystallization rate, the crystallization of the undrawn yarn progresses considerably, and the plastic part of the crystal part before and after Tg. Does not easily deform. In the case of composite with a polyolefin polymer, even when performing contact heating drawing such as hot roller drawing, drawing is performed at a relatively high temperature (about 70 to 100 ° C.) as a guide. Moreover, when heat drawing is performed using a non-contact type heater such as a heating furnace or a heating tube, the temperature is further increased to 150 to 20 at a higher temperature.
It is preferable to set the temperature condition to about 0 ° C.

However, in the present invention, as fiberizing conditions, the spinneret temperature is Tm to Tm + 80 ° C., the shear rate (γ) is 1,000 to 25,000 sec ⁻¹ , and the draft is
(V) It is important to spin at 10 to 500.

Further, the cross-sectional shape of the composite fiber in the present invention is not particularly limited, and it may have a perfect circle shape, a hollow shape, or an atypical cross section depending on the shape of the spinning nozzle. A perfect circle is preferable from the viewpoint of process passability in fiberizing and weaving.

The composite fiber of the present invention can control the shrinkage behavior of the composite fiber when the PVA, which is an island component, is dissolved in water, depending on the production conditions. When it is desired to keep the value low, it is desirable to subject the composite fiber to a heat treatment.
This heat treatment may be carried out at the same time as the drawing in the fiberizing step involving drawing, or may be carried out separately from the drawing. When the heat treatment temperature is increased, the maximum shrinkage ratio of the hollow fiber obtained by dissolving the island component PVA can be lowered, but conversely, the dissolution temperature of the island component PVA in water tends to be high. It is desirable to set the heat treatment conditions while looking at the balance with the maximum shrinkage ratio in the processing step of, and generally, the glass transition point of the island component PVA ~
It is preferable to set the conditions within the range of (Tm-10) ° C.

When the treatment temperature is lower than Tg, a sufficiently crystallized composite fiber cannot be obtained, and for example, when the fabric is used by heat setting, the shrinkage becomes large and the texture of the fabric is hardened, which is not preferable. . The processing temperature is (Tm-
When the temperature exceeds 10 ° C., the fibers are agglomerated, which is not preferable.

The heat treatment may be performed by adding shrinkage to the stretched composite fiber. PV in water when shrinkage is added to the composite fiber
The shrinkage rate of the composite fiber until A dissolution is small. The applied shrinkage is preferably 0.01 to 5%, more preferably 0.1 to 0.5%, and particularly preferably 1 to 4%. The applied contraction is 0.
If it is less than 01%, the effect of reducing the maximum shrinkage ratio of the composite fiber when PVA is dissolved is not substantially obtained, and if the added shrinkage exceeds 5%, the composite fiber sags during the shrinking treatment and becomes stable. Cannot add shrinkage.

In the present invention, the fact that PVA is “water-soluble” means that it dissolves at a temperature of 40 ° C. or higher, regardless of the length of time until dissolution. Then, by changing the type of PVA and the manufacturing conditions of the composite fiber, the melting temperature of the PVA island component in the present invention is 30 ° C to
Although it is possible to obtain a conjugate fiber having a temperature of 100 ° C., in order to balance all properties of practicality and water solubility,
It is preferable to use a composite fiber composed of a PVA island component having a melting temperature of 40 ° C. or higher.

The dissolution treatment temperature may be appropriately adjusted according to the dissolution temperature of PVA, but of course the higher the treatment temperature, the shorter the treatment time. 100 ° C when using hot water
The hot water treatment under the above high temperature and high pressure is most preferable. In addition,
Soft water is usually used as the aqueous solution, but an alkaline aqueous solution,
It may be an acidic aqueous solution or may contain a surfactant and the like.

When the composite fiber of the present invention is treated with hot water to dissolve and remove the PVA component, a nonionic surfactant,
A scouring agent containing an anionic surfactant or the like as a component and other additives may be included. The dissolution and removal of PVA by the hot water treatment may be performed on the composite fiber alone, or may be performed after the fiber structure containing the composite fiber is formed. The temperature and the treatment time during the hot water treatment include various factors such as the fineness of the composite fiber, the ratio of the island component in the composite fiber, the distribution state of the island component, the ratio of the thermoplastic polymer of the sea component, the type, and the morphology of the fiber structure. It can be adjusted appropriately according to the requirements of. The hot water treatment temperature is 60 ° C or higher, preferably 80 ° C or higher. As a method of hot water treatment,
Examples thereof include a method of immersing the composite fiber and the fiber structure in a hot water solution, and a method of applying a hot water solution to them by a method such as a pad or spray.

In the present invention, PVA is removed from the composite fiber as an aqueous solution by the hot water treatment as described above.
Such PVA has biodegradability and is decomposed into water and carbon dioxide when treated with activated sludge or buried in soil. Further, the dissolved and removed PVA is almost completely decomposed within 2 days to 1 month when continuously treated with activated sludge in the state of an aqueous solution. From the viewpoint of biodegradability, the saponification degree of the fiber is 90 to 9
9.99 mol% is preferable, 92-99.98 mol% is more preferable, 93-99.97 mol% is especially preferable. The 1,2-glycol bond content of the fiber is 1.
0 to 3.0 mol% is preferable, 1.2 to 2.5 mol% is more preferable, and 1.3 to 1.9 mol% is particularly preferable.
When the 1,2-glycol bond amount of PVA is less than 1.0 mol%, not only the biodegradability of PVA deteriorates, but also the melt viscosity is too high and the spinnability of the conjugate fiber deteriorates. is there. When the 1,2-glycol bond content of PVA is 3.0 mol% or more, the thermal stability of PVA may deteriorate and the spinnability may decrease.

In the present invention, PVA in the composite fiber is selectively removed by the hot water treatment, and the olefinic monomer units 50 to 10 having one or a plurality of hollow portions are formed.
Polymer block (A) consisting of 0% by weight and 50 to 0% by weight of a vinyl-based monomer unit copolymerizable with the monomer, and 0.1 to 100% by weight of (meth) acrylic acid-based monomer unit % And 9-9 to 0% by weight of a vinyl-based monomer unit copolymerizable with the monomer, the block copolymer (I) is comprised from 5 to 95% by weight. Hollow fibers composed of a polyolefin-based polymer (II) are produced, but the greatest feature of the present invention is that a sea component composed of a thermoplastic polymer such as polypropylene, which is considered to hardly swell in water. PV completely surrounded by
That is, the island component is beautifully dissolved and removed by hot water treatment to form hollow fibers. When the composite fiber has a cut surface such as staple fiber, PVA is applied from the end surface of the fiber.
It is conceivable that the
PVA can be dissolved and removed neatly even in the state of long fibers having substantially no cut surface, and it is no exaggeration to say that this fact overturns the conventional wisdom. In particular, polypropylene fibers having a porous hollow structure are difficult to obtain even by containing a foaming agent or by a very special method, but by using the conjugate fiber of the present invention, it is extremely rational and practical. It is possible to manufacture. In addition, the island component PVA has excellent hygroscopicity and moisture retention, so by applying this property, it is possible to partially dissolve and remove the PVA depending on the purpose (use) to form voids and at the same time leave the island component PVA. Is.

The area ratio (hollow ratio) of the hollow portion in the hollow fiber of the present invention is preferably 2% or more, and if it is less than 2%, the lightness and swelling feeling may not be sufficiently exhibited. Therefore, it is preferable that the area ratio of the hollow portion is 5% or more. If the area ratio of the hollow portion is too large, the fiber strength will be insufficient. Therefore, the area ratio is preferably 70% or less, more preferably 50% or less.

The hollow fiber of the present invention thus obtained is particularly taffeta, decin, georgette, crepe, because of its lightness, flexibility, opacity, and swelling feeling.
It is suitable for woven fabrics such as textured yarns and twills, or knitted fabrics such as jersey, smooth and tricot. Furthermore, it can be used not only for clothing, but also for non-woven fabrics, medical applications, sanitary materials, and various living materials such as stuffing materials. It can also be used as an interior material for automobiles, a sound deadening material, and a vibration isolator as a fiber laminate. It is also possible to make paper.

[0095]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
The parts and% in the examples relate to mass unless otherwise specified.

[PVA analysis method] PVA analysis method was in accordance with JIS-K6726 unless otherwise specified. The modification amount is 500 MHz proton NMR (JEOL GX-5) using modified polyvinyl ester or modified PVA.
00) Determined by measurement with a device. The content of alkali metal ions was determined by the atomic absorption method.

The 1,2-glycol bond content was measured by the method described above. The ratio of the amount of hydroxyl groups of 3 chains by the triad display of PVA of the present invention was determined by the following measurement. After saponifying PVA to a saponification degree of 99.5 mol% or more, it was sufficiently washed with methanol, and then dried at 90 ° C. under reduced pressure for 2 days, and then dissolved in d6-DMSO.
500 MHz Proton NMR (JEOL GX-50
0) 65 degreeC measurement was performed with the apparatus. The peak derived from the hydroxyl group of the vinyl alcohol unit in PVA appears in the region of chemical shift from 4.05 ppm to 4.70 ppm,
This integrated value is the vinyl alcohol unit amount (II). The central hydroxyl group of the 3-chain hydroxyl group according to the triad representation of PVA is 4.5 ppm for the isotacticity chain and 4.3 for the heterotacticity chain, respectively.
It appears at 6 ppm and 4.13 ppm for the syndiotacticity chain. The sum of the integrated values of the three is the amount of the central hydroxyl group (I) of the three-chain hydroxyl group by the triad display.
And The mole fraction of the central hydroxyl group of the 3-chain hydroxyl group in the triad notation with respect to the vinyl alcohol unit of the PVA of the present invention is represented by 100 × (I) / (II).

[Melting Point] The melting point of PVA was determined by using DSC (Mettler, TA3000) in nitrogen and at a heating rate of 10
PVA when the temperature was raised to 250 ° C. at a rate of 10 ° C./min, cooled to room temperature, and then raised to 250 ° C. at a rate of 10 ° C./min again.
The temperature at the peak top of the endothermic peak indicating the melting point of

[Removal rate of PVA in hot water] Regarding the conjugate fiber of the present invention, when the melting temperature of PVA constituting the conjugate fiber in hot water is Tα (° C), (Tα + 40) ° C The mass reduction rate after treatment with hot water for 40 minutes, water washing for 5 minutes, and drying was taken as the PVA removal rate. It should be noted that Tα can be obtained, for example, as a temperature when a load of 2.2 mg / decitex is applied to the fiber made of the PVA alone, the fiber is hung in water, the water temperature is raised, and the fiber is cut.

[Measurement of Area Ratio of Hollow Portion] An SEM photograph was taken of the cross section of the hollow fiber yarn, and the area was calculated from the area of the porous hollow portion and the total area of the hollow fibers in the cross section.

[Measurement of Dyeing Rate] The dye solution before and after dyeing was diluted with a mixed solvent of acetone / water (volume ratio 1/1),
The absorbance of the diluted solution was measured and calculated by the following formula. First-arrival rate (%) = {(D−C) / C} × 100 C: Absorbance at maximum absorption wavelength of dye solution after dyeing D: Absorbance at maximum absorption wavelength of dye solution before dyeing

[Washing fastness] The washing fastness was evaluated according to the method A-2 described in JIS L-0844.

[Evaluation of texture (lightness, texture)] The fabric was evaluated by 10 panelists and evaluated according to the following criteria. ◎: 9 or more people judged that the feeling of lightness, softness and swelling was excellent ○: 7-8 people judged that the feeling of lightness, softness and swelling were excellent △: 5-6 people feeling light , Judged to be excellent in both softness and bulge x: judged to be inferior in lightness, softness and bulge for 6 or more people

[Production of ethylene-modified PVA] A 100-liter pressure reactor equipped with a stirrer, nitrogen inlet, ethylene inlet and initiator inlet was charged with 29.0 kg of vinyl acetate and 31.0 kg of methanol and heated to 60 ° C. After heating 3
The system was replaced with nitrogen by bubbling nitrogen for 0 minutes. Next, ethylene was introduced and charged so that the reactor pressure became 5.9 kg / cm ² (5.8 × 10 ⁵ Pa). 2, as an initiator
A 2.8 g / L solution of 2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMV) dissolved in methanol was prepared, and bubbling with nitrogen gas was performed to substitute nitrogen. After adjusting the temperature inside the polymerization tank to 60 ° C., 170 ml of the above initiator solution was injected to start polymerization. During the polymerization, ethylene was introduced to make the reactor pressure 5.9 kg / cm ² (5.8 × 10 ⁵ Pa) and the polymerization temperature 60 ° C.
Maintained at 610 ml / hr using the above initiator solution.
Then, AMV was continuously added to carry out polymerization. After 10 hours, the polymerization was stopped by cooling when the polymerization rate reached 70%. After removing the ethylene by opening the reaction tank, nitrogen gas was bubbled to completely remove the ethylene. Then, the unreacted vinyl acetate monomer was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate. To 200 g of a methanol solution of polyvinyl acetate adjusted to have a concentration of 50% by adding methanol to the obtained polyvinyl acetate solution (100 g of polyvinyl acetate in the solution), 46.5 g (in polyvinyl acetate) was added. Molar ratio (MR) to vinyl acetate unit
Saponification was carried out by adding an alkaline solution of 0.10) (10% methanol solution of NaOH). About 2 after adding alkali
The gelled system was crushed with a crusher in minutes, and allowed to stand at 60 ° C. for 1 hour to allow saponification to proceed.
0 g was added to neutralize the remaining alkali. After confirming the completion of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration, and the mixture was left standing and washed at room temperature for 3 hours. After the above washing operation was repeated 3 times, the PVA obtained by centrifugal deliquoring was allowed to stand in a dryer at 70 ° C. for 2 days to obtain dried PVA. The degree of saponification of the obtained ethylene-modified PVA was 98.4 mol%.
The content of sodium measured by an atomic absorption spectrophotometer using the solution of the modified PVA dissolved in an acid after ashing was 0.01 parts by mass with respect to 100 parts by mass of the modified PVA. In addition, a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization is n-
Precipitation in hexane and reprecipitation by dissolving in acetone were repeated three times, and then dried under reduced pressure at 80 ° C. for 3 days to obtain purified polyvinyl acetate. The polyvinyl acetate was dissolved in DMSO-d6 and subjected to 500 MHz proton NMR (JEOL GX-
The content of ethylene was 8.4 mol% when measured at 80 ° C. using 500). The above methanol solution of polyvinyl acetate was saponified at an alkali molar ratio of 0.5, and the pulverized product was allowed to stand at 60 ° C. for 5 hours to proceed with saponification, followed by methanol soxhlet for 3 days, and then at 80 ° C. The product was dried under reduced pressure for 3 days to obtain a purified ethylene-modified PVA. The average degree of polymerization of the PVA was measured by the conventional method J
It was 330 when measured according to IS K6726. The 1,2-glycol bond content of the purified PVA and the content of hydroxyl groups in the 3-chain hydroxyl group were adjusted to 500 MHz proton N.
It was 1.50 mol% and 83%, respectively, when determined as described above from the measurement by the MR (JEOL GX-500) apparatus. Furthermore, 5 of the purified modified PVA
% Aqueous solution was prepared to form a cast film having a thickness of 10 μm. After the film was dried under reduced pressure at 80 ° C. for 1 day, the melting point of PVA was 208 ° C. as measured by the above-mentioned method using DSC (Mettler, TA3000).

<Production Example 1> [Production of Polyester Copolymer (II)] Pre-dried PBT (Kuraray Co., Ltd. "S1000"
F ”; intrinsic viscosity [η] = 0.85) 50 parts by mass and 1
Triblock copolymer composed of polystyrene block / 1,3-butadiene / isoprene hydrogenated copolymer block / polystyrene block having a hydroxyl group at one end at a ratio of 0.8 per molecule (hereinafter referred to as "hydrogenated SBIS-OH"). 50 parts by mass), and then the mixture is supplied to a twin-screw extruder (“TEX44C” manufactured by Japan Steel Works, Ltd.), melt-kneaded at 250 ° C., extruded, and then cooled and cut. Pellets were produced. The pellets were transferred to a solid-state polymerization apparatus having a gas introduction port, an exhaust port, a vacuum connector, etc., and treated at 120 ° C. for about 4 hours under the introduction of nitrogen gas to be dried and crystallized. Then, the internal pressure of the solid phase polymerization apparatus was reduced to about 26.7 Pa and the temperature was raised to 200 ° C. to start the solid phase polymerization reaction. After the solid phase polymerization reaction for about 20 hours, nitrogen gas was supplied to return the system to normal pressure. The reaction product obtained by solid phase polymerization was dissolved in a mixed solvent of hexafluoroisopropanol / chloroform (1/1 volume), the solution was poured into tetrahydrofuran to form a precipitate, and the precipitate was recovered. . The precipitate thus obtained was heated under reflux in chloroform, then filtered off, and the chloroform solution was concentrated and dried to give a block derived from PBT and hydrogenated SBIS-.
A diblock copolymer consisting of a block derived from OH was isolated.

Example 1 Using the modified PVA obtained above as an island component, the polyester-based copolymer (II) obtained in Production Example 1 and polypropylene (Japan Polychem, SA2D) were mixed at a ratio of 20:80. The polymer composition (I) prepared as
The maximum temperature of the zone A was 230 ° C., and the unspun yarn was spun at a spinning temperature of 250 ° C. and a spinning speed of 1000 m / min using a composite spinning component in which melt retention of PVA did not occur as much as possible.
Contact with a 0 ° C heat roller and a 140 ° C heat plate,
By drawing at a draw ratio of 3.5 times, a 83 dtex / 24f composite fiber having a fiber cross section and a composite ratio as shown in Table 1 was obtained. Further, knitted with a knitting machine and 170 ℃
And preset for about 40 seconds. Next, hot water treatment was performed with an aqueous solution containing 1 g / liter of Intol MT Conc (anion activator, manufactured by Meisei Chemical Co., Ltd.) at a bath ratio of 50: 1, a temperature of 120 ° C., and a time of 40 minutes. After thorough washing with water, a tubular knitted fabric having a PVA removal rate shown in Table 1 was obtained, and dyed with a disperse dye. Table 2 shows the evaluation results of tubular knitting including dyeability and lightness. 1) Dyeing conditions Temperature × time = 130 ° C × 40 minutes Dye: Dianix Navy Blue SPH (Dystar) 5% omf Dispersant: Disper TL (Meisei Chemical Industry Co., Ltd.) 1g / l Acetic acid (50%): 1cc / l Bath ratio = 1:50 2) Reduction cleaning conditions 80 ° C. × 20 minutes Hydrosulfite 1 g / l Sodium hydroxide 1 g / l Amylazine D (Daiichi Kogyo Seiyaku Co., Ltd.) 1 g / l

[0107]

[Table 1]

[0108]

[Table 2]

From the results shown in Table 2 above, the knitted fabric made of the porous hollow fibers defined by the present invention had a deep dark color in the dyed knitted fabric and was excellent in fastness. .
In addition, it had a very light feeling and had an excellent soft and swelling texture.

Examples 2 to 7 In Example 2, the composite ratio and the island component removal rate were changed, and in Examples 3 to 7, the fiber cross section, the number of islands, and the island component removal rate were changed. Fiberization, knitted fabric formation and evaluation were performed in the same manner as in Example 1 except that the conditions were as shown. All the fabrics had good dyeability, were excellent in lightweight feeling, and had an excellent soft and swelling feeling.

Examples 8 to 11 As shown in Table 1, fiberization and knitting were performed in the same manner as in Example 1 except that the modified species and modification amount of the island component were changed.
An evaluation was performed. All fabrics have good dyeability,
It had an excellent feeling of lightness, softness and swelling.

Examples 12 to 13 Fiberizing and knitting were carried out in the same manner as in Example 1 except that the ratio of the polyester copolymer (II) of the sea component polymer to the olefin polymer was changed as shown in Table 1. The ground was created and evaluated. All the fabrics had good dyeability, were excellent in lightweight feeling, and had an excellent soft and swelling feeling.

Examples 14 to 15 Fiberizing and knitting were performed in the same manner as in Example 1 except that the kind of the olefin polymer, the fiber cross section and the like of the polymer composition (I) were changed as shown in Table 1. Was created and evaluated. All the fabrics had good dyeability, were excellent in lightweight feeling, and had an excellent soft and swelling feeling.

Comparative Examples 1 and 2 Fiberization and knitting were carried out in the same manner as in Example 1 except that the ratio of the polyester copolymer (II) of the sea component polymer to the olefin polymer was changed as shown in Table 1. The ground was created and evaluated. When the mixing ratio of Comparative Example 1 was 1:99, the dyeing rate was low and the degree of contamination was low, and it could not be said that the dyeing was performed. In the case of Comparative Example 2 in which the mixing ratio was 98: 2, the spinnability was poor, and the film could be wound up for an extremely short time.

[Brief description of drawings]

FIG. 1 is a fiber cross-sectional view showing an example of a cross-sectional shape of a conjugate fiber of the present invention.

FIG. 2 is a fiber cross-sectional view showing an example of the cross-sectional shape of the conjugate fiber of the present invention.

FIG. 3 is a fiber cross-sectional view showing an example of the cross-sectional shape of the conjugate fiber of the present invention.

FIG. 4 is a fiber cross-sectional view showing an example of the cross-sectional shape of the conjugate fiber of the present invention.

FIG. 5 is a fiber cross-sectional view showing an example of the cross-sectional shape of the conjugate fiber of the present invention.

FIG. 6 is a fiber cross-sectional view showing an example of the cross-sectional shape of the conjugate fiber of the present invention.

[Explanation of symbols]

1: Sea component 2: Island component

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4L031 AB06 AB11 BA33 CA07 CA16                       CA17 DA00 DA02 DA09                 4L041 AA07 BA02 BA05 BA16 CA10                       CA41 DD11 EE14

Claims (13)

[Claims] 1. A water-soluble polymer composition (I) containing 5 to 95% by weight of a polyester copolymer (II) consisting of a polyester block (IIa) and an addition polymer block (IIb) as a sea component. A composite fiber containing a thermoplastic polyvinyl alcohol polymer (III) as an island component. 2. The water-soluble thermoplastic polyvinyl alcohol polymer (III) contains 0.1 to 20 mol% of α-olefin units and / or vinyl ether units having 4 or less carbon atoms.
The composite fiber according to claim 1, which is a modified polyvinyl alcohol contained. 3. The composite fiber according to claim 2, which contains 4 to 15 mol% of ethylene units and / or propylene units as α-olefin units. 4. The number average molecular weight of the polymer block (A) constituting the block copolymer (IIb) is 1,000 to 10.
The fiber according to claim 1, wherein the polymer block (B) has a number average molecular weight of 1,000 to 100,000. 5. The sea component polymer composition (I) comprises at least one polymer selected from the group consisting of polyethylene, polypropylene, ethylene / α-olefin copolymers and hydrogenated conjugated diene copolymers. The composite fiber according to claim 1, wherein 6. A hollow fiber composed of a polymer composition (I) containing 5 to 95% by weight of a polyester copolymer (II) composed of a polyester block (IIa) and an addition polymer block (IIb). 7. The polymer composition (I) comprises at least one polymer selected from the group consisting of polyethylene, polypropylene, ethylene / α-olefin copolymers and hydrogenated conjugated diene copolymers. The hollow fiber according to item 6. 8. The number of hollow portions is 1 or more, and the hollow ratio is 2%.
The hollow fiber according to claim 6, which is not less than 65% and not more than 65%. 9. The method according to claim 8, wherein the number of hollow portions is 10 or more.
Hollow fiber according to. 10. The hollow fiber according to claim 6, which is a long fiber. 11. A fiber structure containing the hollow fiber according to claim 6 in at least a part thereof. 12. Treating the conjugate fiber according to claim 1 with water to dissolve and remove at least part of the water-soluble thermoplastic polyvinyl alcohol polymer (III) from the conjugate fiber. A method for producing a hollow fiber, comprising: 13. A water-soluble thermoplastic polyvinyl alcohol-based polymer (II) prepared by treating a fiber structure containing the conjugate fiber according to claim 1 with water,
A method for treating a fibrous structure, characterized in that at least a part of I) is removed by dissolution.