JPH06280156A - Method for producing fiber, thread or fabric - Google Patents

Abstract

PURPOSE:To obtain a fabric having excellent handle, etc., by subjecting conjugate yarn comprising a specific copolyester and another fiber-forming polymer to alkali weight-loss treatment and partially dissolving the copolyester. CONSTITUTION:Fabric, yarn, etc., comprising conjugate yarn obtained by subjecting (A) a copolyester composed of A1: 0.5-10mol% of a dicarboxylic acid unit of formula I (Ar is trifunctional aromatic group; M is metal atom) based on total acid components constituting the copolyester, A2: 1-49wt.% of a diol unit of formula II (R<1> is alkylene; (m) is 10-100) and 1-49wt.% of a side chain group unit of formula III (R<2> is alkylene; R<3> is 1-18C hydrocarbon; (n) is 10-100; (x) and (y) are 0 or 1) based on the weight of the polyester, and 2-50wt.% total of the components A2+A3 and (B) another fiber-forming polymer having alkali solubility lower than that of the component A is treated with an alkali and the component A is partially dissolved in a short time to give fabric composed of surface yarn similar to soft natural yarn.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fiber having a soft and excellent feeling, surface condition and appearance similar to natural fiber, a conjugate fiber which gives a yarn and a fabric, and the conjugate fiber produced by using the conjugate fiber. The fibers, yarns and cloths having the above-described texture and appearance can be obtained by subjecting the yarns and cloths to an alkali treatment. Also, according to the method of the present invention, those fibers and fiber products have an extremely short alkali treatment time. Can be obtained efficiently.

[0002]

2. Description of the Related Art Synthetic fibers such as polyester and polyamide and cloths made of them have many excellent characteristics such as easy care, but their single yarn fineness is large and their cross-sectional shape is simple. Depending on things such as silk, cotton,
Compared with natural fibers such as hemp, the texture and luster are more monotonous, and it feels cold like plastic, making it difficult to obtain high-quality products like natural fibers.

In recent years, in order to improve the above-mentioned drawbacks of synthetic fibers, various attempts have been made to deform the cross-sectional shape of the fibers, crimp processing, and to form composite fibers. One of the composite fibers is polyamide. A technique has been proposed in which it is formed from polyester and fibrillated to make it ultrafine (JP-B-53-35633, JP-B-56-16231, etc.). However, in that case, although the texture becomes slightly soft, it tends to be of a low quality because the characteristic slimy feeling due to the polyamide fiber cannot be improved, and it is necessary to use expensive benzyl alcohol etc. at the time of fibrillation. However, there is a drawback that the processing cost becomes high.

In order to obtain synthetic fibers and ultrafine fibers having a soft texture, a composite fiber composed of an alkali-soluble polymer and another polymer is formed, and the alkali-soluble polymer is dissolved and removed with an alkali. Various methods have been used to reduce or increase the amount. As such a conventional technique, a method of treating a composite fiber of (i) a polyester having a metal sulfonate-containing ester unit copolymerized with another polymer with an alkali 58-98425), and (ii) a method of subjecting a composite fiber of an alkali-soluble polyester obtained by copolymerizing an isophthalic acid component having a metal sulfonate group and a polyalkylene glycol and another polymer to alkali treatment (Japanese Patent Laid-Open Publication No. Sho 62-98425). 58-
No. 54022) is known.

However, in the case of the above method (i), the metal sulfonate-containing ester unit-containing polyester, which is one component of the composite fiber, is more excellent in alkali solubility than ordinary polyesters such as polyethylene terephthalate. However, the alkali solubility thereof is not yet sufficient, and it takes a considerable amount of time for the alkali reduction treatment, and the physical properties of the fiber after the treatment are considerably deteriorated by the alkali treatment for a long time. When the proportion of the metal sulfonate-containing ester unit is increased in order to increase the alkali solubility, the polyester has a drawback that the viscosity of the polyester becomes remarkable and spinning becomes difficult.

In the case of the method (ii), the polyester prepared by copolymerizing the metal sulfonate group-containing isophthalic acid and the polyalkylene glycol used therein is prepared by copolymerizing only the metal sulfonate group-containing ester unit (i). Alkali solubility is much higher than that of the polyester used in (1), and the alkali treatment can be carried out fairly quickly. However, its alkali solubility is not yet sufficient, and especially when trying to obtain ultrafine fibers or complicated fibers having a cross-sectional shape by alkali treatment, the polymer component to be left is largely eroded or deteriorated by alkali. Receive. In this method (ii), the alkali solubility can be increased to some extent by increasing the copolymerization ratio of polyalkylene glycol. However, the polyester obtained by copolymerizing a large amount of polyalkylene glycol has a melt viscosity during spinning. Has a drawback that the pressure balance becomes poor when a composite fiber with other polymer is produced, the processability deteriorates, and spinning becomes difficult.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is a synthetic fiber, a yarn and a fabric having a soft and excellent feeling, surface condition and appearance similar to natural fiber, and such fiber, yarn and fabric. It is an object of the present invention to provide an industrially advantageous method capable of efficiently and smoothly producing a product in a short time without using an expensive treating agent or the like. Further, when the fibers or cloth having the above-mentioned excellent properties are obtained by the alkali treatment, the alkali treatment can be carried out more quickly and in a shorter time, and the residual polymer components are not eroded or deteriorated. It is to provide such a method.

[0008]

Means for Solving the Problems The inventors of the present invention continued their research to solve the above-mentioned problems and found that a specific proportion of copolymerized units consisting of an isophthalic acid component having a metal sulfonate group and a polyalkylene glycol component was obtained. In addition, a copolyester obtained by further copolymerizing a specific side chain type polyoxyalkylene group in a specific ratio is used in the conventional technique as described in (i) or (ii) above. It has been discovered that it has a higher alkali solubility than existing copolyesters, and that the copolyesters have excellent spinnability and can be used to manufacture composite fibers with other fiber-forming polymers with good processability. did. Then, the present inventors continued their research based on such findings, and when the composite fiber using such a specific copolyester or the yarn or cloth formed thereof was treated with alkali, the copolyester was While being dissolved and removed in a very short time under mild alkaline treatment conditions, the other fiber-forming polymer portion remains in an ultrafine fibrous state without being deteriorated or eroded, and has an excellent soft texture. The present invention has been completed by finding that fibers, cloths and the like having a surface state and appearance can be manufactured very easily in a short time.

That is, the present invention provides (A) (a)
(I);

[0010]

[Chemical 7] (In the formula, Ar represents a trivalent aromatic group and M represents a metal atom.)
A dicarboxylic acid unit partially containing a dicarboxylic acid unit represented by: (b) the following formula (II);

[0011]

Embedded image A diol unit represented by —O— (R ¹ —O) _m — (II) (wherein R ¹ is an alkylene group, and m is a number of 10 to 100); and (c) Formula (III) of

[0012]

[Chemical 9] (In the formula, R ² is an alkylene group, R ³ is a hydrocarbon group having 1 to 18 carbon atoms, n is a number of 10 to 100, and x and y each represent 0 or 1); A dicarboxylic acid unit represented by the formula (I), wherein the dicarboxylic acid unit represented by the formula (I) is 0.5 to 10 mol% of all acid components constituting the copolymerized polyester, and a diol unit represented by the formula (II). And 1 to 49% by weight of the side chain unit represented by the formula (III), respectively, based on the weight of the copolyester, and
A copolymerized polyester in which the total content of diol units represented by (II) and side chain units represented by formula (III) is 2 to 50% by weight based on the weight of the copolymerized polyester; and (B) At least one kind of other fiber-forming polymer; which is a composite fiber, and the composite fiber or a yarn or a cloth produced by using the composite fiber is treated with an alkali and at least the above-mentioned copolyester (A). A method for producing a fiber, thread or fabric characterized by partially removing by dissolution. Furthermore, the present invention includes the fibers, threads and fabrics produced by the above method.

In the present invention, as the dicarboxylic acid unit constituting the copolyester, the dicarboxylic acid unit represented by the above formula (I) [hereinafter referred to as "dicarboxylic acid unit (I)"
Is included in a proportion of 0.5 to 10 mol% of all acid components constituting the copolyester.
It is preferably contained in a proportion of ˜7 mol%. When the copolymerization ratio of the dicarboxylic acid unit (I) is less than 0.5 mol%, the copolymerized polyester (A) becomes difficult to dissolve during alkali treatment, while when it exceeds 10 mol%, the metal sulfonate component Thickening occurs during the polycondensation reaction for producing the copolyester (A) by ionic interaction,
It becomes difficult to continue the polycondensation reaction until the copolyester (A) has a desired intrinsic viscosity.

In the dicarboxylic acid unit (I), Ar is a trivalent aromatic group, M is a metal atom, and the group Ar is a 1,3,5-benzenetriyl group, 1,2,3. −
Benzenetriyl group, benzenetriyl group such as 1,2,4-benzenetriyl group, 1,3,6-naphthalenetriyl group, 1,3,7-naphthalenetriyl group, 1,
Examples thereof include naphthalenetriyl groups such as 4,5-naphthalenetriyl group and 1,4,6-naphthalenetriyl group, and the metal atom M is sodium, potassium,
It is preferably an alkali metal atom such as lithium.
The copolyester (A) may have only one type of dicarboxylic acid unit (I) or may have two or more types of dicarboxylic acid unit (I).

The carboxylic acid units other than the dicarboxylic acid unit (I) constituting the copolyester (A) include terephthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2, 5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, 3,3′-biphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 4,4′-diphenylmethanedicarboxylic acid, 4,4'-diphenylisopropylidene dicarboxylic acid, 1,2-diphenoxyethane-4 ', 4 "-dicarboxylic acid, 2,5-anthracene dicarboxylic acid, 2,6-
Aromatic dicarboxylic acids such as anthracene dicarboxylic acid and 2,5-pyridinedicarboxylic acid; aromatic hydroxycarboxylic acids such as β-hydroxyethoxybenzoic acid and p-oxybenzoic acid; or aromas derived from their ester-forming derivatives. Examples of the aromatic dicarboxylic acid unit may include one type or two or more types of these aromatic dicarboxylic acid units.

With the above aromatic dicarboxylic acid unit,
Aliphatic dicarboxylic acids such as adipic acid, azelaic acid and sebacic acid; Copolyesters (A) which may contain units derived from alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and ester-forming derivatives thereof It is desirable that 70 mol% or more of all the acid component units constituting the above are composed of aromatic dicarboxylic acid units, particularly terephthalic acid units.

In the present invention, the copolymerized polyester (A) has a diol unit represented by the above formula (II) [hereinafter referred to as "diol unit (II)"] in the weight of the copolymerized polyester (A). It is necessary to contain 1 to 49% by weight based on the above. When the proportion of the diol unit (II) is less than 1% by weight, the alkali solubility of the copolyester (A) is lowered, while when it exceeds 49% by weight, spinning becomes difficult.

In the diol unit (II), 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 dissolved in an alkali. It is particularly preferable from the standpoint of sex. In the diol unit (II), an ethylene group and a propylene group may be present in the same molecule. Further, in the diol unit (II), m representing 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 (II), 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 (II) 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 copolyester (A), the diol unit (II) may be contained alone or in combination of two or more.

The copolyester (A) may further have a diol unit other than the above-mentioned diol unit (II). Examples of the other diol unit include ethylene glycol, propylene glycol, Aliphatic diols such as trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, nonamethylene glycol, 3-methylpentane-1,5-diol, 2-methyloctane-1,8-diol, diethylene glycol; cyclohexane Examples thereof include units derived from alicyclic diols such as dimethanol, and these diol units may be contained alone or in combination of two or more. From the point of view of fiber formation when manufacturing composite fibers,
70 mol% or more of the other diol unit is a unit derived from a linear alkylene glycol having 2 to 6 carbon atoms such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol and hexamethylene glycol. Is preferred.

In the present invention, the copolyester (A) further comprises a side chain unit represented by the above formula (III) [hereinafter referred to as "side chain unit (III)"] of the copolyester (A). It is necessary to have 1 to 49% by weight, based on the weight. When the proportion of the side chain unit (III) is less than 1% by weight, the alkali solubility is lowered, while when it exceeds 49% by weight, spinning becomes difficult.

The side chain unit (III) has the following formula (IV):

[0022]

[Chemical 10] [Wherein D is a group capable of reacting with a dicarboxylic acid component or a diol to introduce the side chain unit (III) represented by the above formula (III) into the main chain of the copolyester (A). And R ² , R ³ and n represent the same groups as above] can be introduced into the copolyester (A) by reacting the compound at the time of production of the copolyester (A). .

In the compound represented by the above formula (IV),
Examples of the ester-forming group D include, for example, the following formulas;

[0024]

[Chemical 11] A glycidyl group represented by or the following formula;

[0025]

[Chemical 12] 2,3-dihydroxypropyl group and the like can be mentioned.

In the side chain unit (III), R ² has 1 to 1 carbon atoms.
4 is preferable, an ethylene group or a propylene group is more preferable, and an ethylene group is particularly preferable. Further, specific examples of R ³ include methyl, ethyl, n-propyl, isopropyl, n-butyl and se.
Alkyl groups such as c-butyl, tert-butyl, n-pentyl, n-octyl, 2-ethylhexyl, n-dodecyl, n-stearyl; cycloalkyl groups having 3 to 18 carbon atoms such as cyclohexyl; phenyl, nonylphenyl, etc. An aryl group having 6 to 18 carbon atoms can be mentioned.

In the side chain unit (III), an ethylene group and a propylene group may be present in the same molecule. The side chain unit (I
In II), n indicating the degree of polymerization of the oxyalkylene unit is a number in the range of 10 to 100, and n is preferably a number in the range of 20 to 80, as described above. n
Is less than 10, the alkali solubility decreases, while 1
If it exceeds 00, the alkali solubility does not improve so much and causes coloring.

Specific examples of the side chain unit (III) include polyoxyethylene glycol-methyl-glycidyl ether, 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-
Glycidyl ether, polyoxyethylene glycol-
2-ethylhexyl-2,3-dihydroxypropyl ether, polyoxyethylene glycol-n-dodecyl-glycidyl ether, polyoxyethylene glycol-n-dodecyl-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, polyoxy Ethylene 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,
From 3-dihydroxypropyl ether, polyoxyethylene / polyoxypropylene glycol copolymer n-propyl-glycidyl ether, polyoxyethylene / polyoxypropylene glycol copolymer n-propyl-2,3-dihydroxypropyl ether, etc. Derived units may be mentioned, and these units may be contained alone in the copolyester (A) or 2
More than one species may be included.

In the copolyester (A), the total content of the diol unit (II) and the side chain unit (III) is from 2 to 2 based on the weight of the copolyester (A).
It is necessary to be 50% by weight, particularly preferably 5 to 30% by weight. When the total content of the diol unit (II) and the side chain unit (III) is less than 2% by weight, alkali solubility is lowered, while when it exceeds 50% by weight, spinning becomes difficult.

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

Then, the copolyester (A) is prepared by mixing 3% of phenol and tetrachloroethane in an equal weight mixed solvent.
Intrinsic viscosity measured at 0 ° C. is 0.5 dl / g or more, preferably 0.55-1.5 dl / g, especially 0.6-1.0 d
It is preferably 1 / g from the viewpoint of processability during spinning.

The copolyester (A) is used for the dicarboxylic acid component, the diol component and the side chain unit (III) represented by the above formula (IV), which can introduce the above-mentioned units into the copolyester (A). It can be produced by carrying out a polymerization reaction using a compound or the like by a conventional method. For example, in the first step, the raw material components are first used to perform an esterification reaction or a transesterification reaction to produce a low polymer, and then in the second step, the low polymer is reduced under reduced pressure in the presence of a polymerization catalyst. It can be produced by heating to a polycondensation temperature up to the desired degree of polymerization, but the method is not limited to this method. 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.

Then, the above-mentioned copolyester (A) is spun with another fiber-forming polymer (B) to produce a composite fiber. As the other fiber-forming polymer (B), any fiber-forming polymer having a lower alkali solubility than the copolyester (A) can be used. Although not limited thereto, both of the values such that the value obtained by dividing the alkali dissolution rate of the copolyester (A) by the alkali dissolution rate of the fiber-forming polymer (B) is 15 or more, more preferably 25 or more When polymers are combined and combined, the difference in alkali solubility between the two becomes large,
The alkali treatment of the present invention can be carried out more smoothly.

Examples of the fiber-forming polymer (B) include polyester polymers other than the copolyester (A),
Polyamide polymer, olefin polymer such as polypropylene, vinyl chloride polymer, polyvinyl alcohol,
Examples thereof include vinylidene chloride and polyurethane. The fiber-forming polymer (B) may be used alone or in combination of two or more. Among them,
As the fiber-forming polymer (B), another polyester-based polymer that is less soluble in alkali than the copolyester (A) is preferable, and when another polyester-based polymer is used, the copolyester (A) It is possible to obtain a product in which the processability during the composite spinning with is more excellent, the effect of alkali treatment is remarkable, and the texture is good.

As the other polyester polymer, polyethylene terephthalate or polybutylene terephthalate is particularly preferable. In these polyesters, other copolymerization components may be copolymerized at a ratio of 10 mol% or less. Examples of the polymerization component include neopentyl glycol, cyclohexanedimethanol, isophthalic acid, and isophthalic acid having a sulfonate group.

As described in the above-mentioned section of the prior art, a polyester copolymer obtained by copolymerizing isophthalic acid having a sulfonate group (hereinafter referred to as "sulfonate group-containing polyester copolymer") is polyethylene terephthalate or polybutylene. Since it has a higher alkali solubility than terephthalate, it has been conventionally composite-spun with polyethylene terephthalate or polybutylene terephthalate, and the sulfonate group-containing polyester copolymer part is dissolved and removed from the resulting composite fiber with ultrafine fibers. Was manufactured. However, in the conjugate fiber used in the present invention, since the copolymerized polyester (A) has significantly higher alkali solubility than the sulfonate group-containing polyester copolymer, the sulfonate group-containing polyester copolymer remains after the alkali treatment. It can be used as the above-mentioned fiber-forming polymer (B).

In the present invention, when the sulfonate group-containing polyester copolymer is used as the fiber-forming polymer (B), the dye is formed by the presence of the sulfonate group bonded in the polyester copolymer molecule. The affinity with and becomes extremely good, and when dyed with a cationic dye after or at the same time as the alkali treatment, it is possible to obtain a fiber or cloth which is not whitish and has a sharp and deep extremely good color tone and appearance. . However, when a sulfonate group-containing polyester copolymer is used as the fiber-forming polymer (B), the copolymerization ratio of isophthalic acid having a sulfonate group is preferably 3 mol% or less, 3 mol% is more preferable,
1.5 to 2 mol% is more preferable. When the copolymerization ratio of isophthalic acid having a sulfonate group is more than 3 mol%, the viscosity of the polyester is remarkably increased and spinning becomes difficult, and the hydrolyzability during alkali treatment becomes large,
The strength as a thread is significantly reduced.

The composite form of the copolyester (A) and the fiber-forming polymer (B) in the composite fiber is not particularly limited and may be any composite form such as a laminating type, a sea-island type or a core-sheath type. Can be, but copolyester (A)
In order for at least a part of the conjugate fiber to be dissolved and removed during the alkali treatment, it is necessary that the copolyester (A) is exposed on at least a part of the surface of the composite fiber. The composite ratio of the copolyester (A) and the fiber-forming polymer (B) in the composite fiber is not particularly limited, either.
From the standpoints of spinnability in producing the conjugate fiber, strength of the product after alkali treatment, etc., the weight ratio of the copolyester (A): fiber forming polymer (B) = 10: 90 to 90:
It is preferable to combine them at a ratio of 10, and it is advisable to adjust the combination ratio of the two according to each composite form and fiber shape.

The composite fiber composed of the copolyester (A) and the fiber-forming polymer (B) is not limited, but, for example, as shown in (a) to (co) of FIG. Various types such as a laminating type, a sea-island type, a core-sheath type, and a mixed type thereof can be used, and the conjugate fiber of FIG. 1 or a yarn or cloth made of the same is subjected to alkali treatment and a portion of the copolyester (A). When at least a part of is removed, a part of the fiber-forming polymer (B) or a part of the fiber-forming polymer (B) and the copolyester (A) remains to become the corresponding fibers. In addition, in FIG. 1, the component A represents the copolyester (A), and the component B represents the fiber-forming polymer (B).

Particularly in sea-island type and laminating type composite fibers, when the number of islands is increased, the size of individual islands is decreased, or the number of laminating layers is increased, in the case of the present invention, the fibers are Only the copolyester (A) part can be rapidly dissolved and removed before the forming polymer (B) part is eroded by the alkali, so that the alkali treatment makes the ultrafineness smaller than that in the conventional alkali weight reduction treatment. Ultrafine fibers (for example, ultrafine fibers of 0.3d or less) can be obtained. For example, when obtaining such an ultrafine fiber from a sea-island type composite fiber in which the copolyester (A) is the sea and the fiber-forming polymer (B) is the island, the number of islands depends on the single fiber fineness of the composite fiber. However, it is preferable to appropriately set the number of islands according to the single fiber fineness of the composite fiber, and it is desired to obtain ultrafine fibers having a single fiber fineness of 0.1 denier or less after alkali treatment. Even in this case, it is necessary to set the number of islands appropriately. Such ultra-fine fibers obtained by the alkali treatment of the present invention, yarns and cloths made thereof have a soft and supple excellent texture due to their extremely small single fiber fineness.

As another example of the conjugate fiber in the present invention, as shown in FIG. 2A, a copolyester (A) is provided around a core portion C made of a fiber-forming polymer (C). An example is a composite fiber in which a sheath portion in which the fiber-forming polymer (B) and the fiber-forming polymer (B) are mixed in a non-uniform and random manner is formed. In the composite fiber shown in FIG.
The fiber-forming polymer (C) forming the core portion C and the fiber-forming polymer (B) forming a part of the sheath portion may be made of the same polymer or different polymers. However, all of them need to have lower alkali solubility than the copolyester (A).

Then, the composite fiber of FIG. 2A is treated with an alkali to dissolve and remove the copolyester (A) forming a part of the sheath portion, and the core portion C as shown in FIG. A fiber in which fluffs composed of the fiber-forming polymer (B) are randomly left around is obtained. Figure 2 (a)
The fiber and the cloth formed thereof, which have been subjected to the alkali treatment, have a softness and a soft touch due to the extra-fine fluffy body existing around the core portion C, and at the same time, the fibers are elasticized by the core portion C existing inside thereof. Is given,
It is soft and has a very good feel with a good waist.

In the composite fiber shown in FIG. 2A, the core portion is circular, but the core portion does not necessarily have to be circular. For example, as shown in FIGS. To
It may have any shape such as a triangle, a quadrangle, and a polygon, and in that case, the core may be located at the center or at an eccentric position. In addition, a composite fiber composed of a randomly mixed portion of the copolyester (A) and the fiber-forming polymer (B) and a fiber-forming polymer (C) portion is shown in (a) to (a) of FIG.
Not limited to the core-sheath type composite fiber such as (K), for example, the sea-island type as shown in (K) to (K) of FIG. 2 or the bonding as shown in (K) to (C) of FIG. It may be a type of composite fiber. When the conjugate fiber shown in FIG. 2 is treated with an alkali to dissolve and remove the copolyester (A) portion, a fluffy body composed of the fiber-forming polymer (B) is obtained according to each conjugate form. A fiber having a core portion made of the fiber-forming polymer (C) is obtained.

The composite fiber shown in FIG. 2 is prepared by supplying the copolyester (A) and the fiber-forming polymer (B) to a spinneret pack containing a static mixer or the like, and mixing the two randomly with the mixer. By forming a mixed composite stream, and combining the composite stream with the separately supplied stream of the fiber-forming polymer (C) at, for example, the spinning hole of the spinneret or a portion immediately upstream thereof, and spinning out from the spinneret. It can be manufactured.

Taking the composite fiber of FIG. 2A as an example,
For example, as shown in FIG. 3, a static mixer element S is arranged in the mixing plate 1 part of the spinneret pack, and a flow of the copolyester (A) and the fiber-forming polymer (B) is supplied to the static mixer part. Then, both are randomly compounded, and the compound stream is supplied to the periphery of the back side of the spinning hole 7 provided in the spinneret plate 3 through the flow path 4 provided in the distribution plate 2, and at the same time, the fiber-forming polymer ( C) through a channel 5 and a channel 6 and a spinning hole 7 of the spinneret plate 3.
Of the fiber-forming polymer (C) and a sheath formed by randomly mixing the copolyester (A) and the fiber-forming polymer (B) around the core of the fiber-forming polymer (C). Can be produced by spinning from the spinning hole 7.

Further, as one kind of the bonding type composite fiber used in the present invention, a copolymerized polyester (A) and a fiber-forming polymer (B) are shown, for example, in (a) to (c) of FIG. When such a super-flat laminating type composite fiber is formed, the copolyester (A) portion is dissolved and removed by the alkali very easily and in a short time. As a result, as shown in FIG. It is possible to obtain flat ultrafine fibers.

In the super-flat composite fibers as shown in FIGS. 4A to 4C, in order to smoothly dissolve and remove the copolyester (A) component by the alkali treatment, the copolyester ( A): Fiber-forming polymer (B) is preferably compounded in a weight ratio of 1: 1 to 1: 4, more preferably 1.5: 1 to 4: 1. The degree of flatness is determined by measuring the length of the longest side (L) and the length of the shortest side (W) in the super-flat fiber of FIG. 4D obtained after dissolving and removing the copolyester (A). Ratio: L / W = 15 to 100 is preferable. If the L / W is less than 15, the softness is lacking, while if it exceeds 100, the alkali hardly penetrates into the inside of the composite fiber during the alkali treatment.

Due to the extremely high flatness, the ultra-flat fiber obtained as described above and shown in FIG. 4D has a very soft and high-quality texture similar to downy hair.
Moreover, when the above sulfonate group-containing polyester copolymer is used as the fiber-forming polymer (B), a dyed product having extremely excellent gloss and color tone can be obtained. By the way, in the conventional flat fiber, the above L /
Even if the value of W is high, it is about 10, and the flatness is lower than that of the ultra-flat fiber obtained in the present invention, and the softness and suppleness as in the present invention cannot be achieved.

The cross section of the conjugate fiber comprising the copolyester (A), the fiber-forming polymer (B) and, if necessary, the fiber-forming polymer (C) used in the present invention is circular in cross section; It can have any cross-sectional shape such as multi-leaf shape such as leaf-shaped to octalobe shape, T-shape, V-shape, flat shape, rectangular shape and the like, and it is not limited to solid fiber but hollow fiber or porous fiber. It may be. The thickness of the fiber is not particularly limited, and may be any thickness, but from the viewpoint of obtaining a soft-feeling fiber or cloth after alkali treatment, the single fiber fineness of the composite fiber is about 1 It is preferably about 8 to 10 denier.

In the above-mentioned composite fiber, one or more of the copolymerized polyester (A) portion and the fiber-forming polymer (B) or (C) may be added with an antioxidant and / or a coloring agent if necessary. Inhibitor, heat resistance improver, fluorescent bleach,
A flame retardant, a matting agent, a coloring agent, inorganic fine particles and the like may be contained. In particular, if a phosphite-based antioxidant is blended in the copolyester (A) part, the color tone is improved, and if a hindered phenol-based antioxidant is contained, the copolyester ( It is possible to prevent oxidative decomposition and thermal decomposition of the polyoxyalkylene chain in A).

The method for producing the above-described conjugate fiber is not particularly limited, and examples thereof include a method of melt spinning at a low speed or a medium speed, followed by drawing, a direct spinning drawing method at a high speed, and drawing or false twisting simultaneously or successively after spinning. It can be produced by any method such as a method.

In the present invention, the above conjugate fiber, or the yarn or cloth produced using the conjugate fiber is treated with alkali to dissolve at least a part of the copolyester (A) constituting the conjugate fiber. And remove. The alkali treatment may be performed directly on the composite fiber or the yarn made of the composite fiber as described above, but a fabric such as a woven fabric or a non-woven fabric is formed from the composite fiber, and the fabric is alkali-treated.
It is preferable in terms of easiness of treatment, physical properties and texture of the obtained product. The cloth in that case may be formed by the above-mentioned conjugate fiber alone, or may be formed by using the above-mentioned conjugate fiber and a natural fiber or another synthetic fiber in combination.
For example, in the case of a woven fabric, both the warp yarn and the weft yarn may be made of the above-mentioned composite fiber, or only one of them may be made of the above-mentioned composite fiber. Further, the cloth may be formed of the filament of the above-mentioned composite fiber, short fiber, spun yarn, or the like.

In carrying out the alkali treatment, (i)
A method using a treatment liquid containing a strong alkaline substance alone, (ii) a treatment liquid containing a weak alkaline substance alone, and (iii) a treatment liquid containing both a strong alkaline substance and a weak alkaline substance. Any method such as the method used can be adopted.

In the case of the above method (i), it is preferable to use sodium hydroxide, potassium hydroxide, trisodium phosphate or the like as the strong alkaline substance, and the concentration of the strong alkaline substance in the treatment solution is about 2 to 2. About 60 g / l, preferably about 3 to 20 g / l. In the case of this method, if the concentration of the strongly alkaline substance is lower than 2 g / liter, the dissolution rate and the extent of dissolution of the copolyester (A) portion in the composite fiber will be small, and alkali reduction treatment will be performed in a short time. Becomes difficult. On the other hand, when the concentration of the strong alkaline substance is higher than 60 g / liter, the fiber-forming polymer (B) is deteriorated, and the strength of the fiber, thread or cloth is significantly reduced.

Further, in the case of the above method (ii), it is preferable to use sodium carbonate, sodium bicarbonate, sodium silicate, sodium dihydrogen phosphate or the like as the weak alkaline substance, and the weak alkaline substance in the treatment liquid is used. Concentration of about 5 to 200 g / liter, preferably 5
It is recommended to set the amount to about 60 g / liter. In the case of this method, when the concentration of the weakly alkaline substance is lower than 5 g / liter, the dissolution rate and the degree of dissolution of the copolyester (A) portion in the composite fiber are reduced, and the alkali weight reduction treatment is performed in a short time. On the other hand, when the concentration of the weakly alkaline substance is higher than 200 g / liter, the fiber-forming polymer (B) is deteriorated as in the case of the above (i), so that the fiber, the yarn or the cloth is deteriorated. The power of will be greatly reduced.

Further, in the case of the above method (iii),
It is preferable that a strong alkaline substance and a weak alkaline substance are contained in the treatment liquid at a ratio satisfying the following formula and formula.

[0057]

[Equation 1] S <−0.8 W + 60 ... 2 ≦ W <5 [wherein S = concentration of strong alkaline substance (g / liter) W = concentration of weak alkaline substance (g / liter)]

In the case of the method (iii) in which a strong alkaline substance and a weak alkaline substance are used in combination, by using both alkaline substances so as to satisfy the above equations and, the concentration of the strong alkaline substance can be reduced. Also, only the copolyester (A) can be efficiently dissolved and removed, and the fiber-forming polymer (B) portion can be left without being dissolved. In the case of the method (iii), if the concentration of the weakly alkaline substance is less than 2 g / liter, it is necessary to make the concentration of the strongly alkaline substance higher than that of the above formula, and the fiber-forming polymer (B) is added. The alkali erosion becomes large, so that it is difficult to obtain a soft texture similar to natural fiber, and further, the fiber-forming polymer (B) is deteriorated, and the strength of the fiber, thread or cloth is lowered. Further, when the concentration of the strong alkaline substance is -0.8 W + 60 (g / liter) or more, not only the copolymerized polyester (A) portion but also the fiber-forming polymer (B) portion is dissolved and the strength of the fiber is remarkably increased. descend.

In any of the above methods (i) to (iii),
It is preferable to carry out the alkali treatment at a temperature of 70 to 130 ° C. If the temperature is lower than 70 ° C., the alkali weight reduction treatment will take a long time, while if it exceeds 130 ° C., only the copolyester (A) part will be obtained. Instead, the fiber-forming polymer (B) portion, the fiber-forming polymer (C), and other polymer portions to be left remain eroded and deteriorated easily. Further, the above-mentioned alkali treatment can be carried out so that a part or all of the copolyester (A) is dissolved in the composite fiber constituting the fiber, yarn or cloth, and preferably the copolyester (A). 90% by weight or more is dissolved and removed, and the fiber-forming polymer (B) and the fiber-forming polymer (C) are preferably not dissolved extremely.

The alkali treatment of the present invention is carried out by scouring a cloth or the like,
It may be carried out at the same time as the desizing or before or after it, but it is preferred to be carried out at the same time as the scouring and desizing, because the number of treatment steps is small. Further, the alkali treatment may be carried out in a static state, but when the alkali treatment liquid is caused to collide with fibers, yarn, cloth or the like, or the alkali treatment liquid or the fiber to be treated or the fabric is stirred, The copolyester (A) portion can be more rapidly dissolved and removed, and such alkali treatment can be carried out by using, for example, a high pressure liquid flow type device or a high pressure washer device.

The alkali treatment is preferably carried out in the presence of a nonionic surfactant, anionic surfactant, etc., whereby swelling, softening of the composite fiber, penetration of alkali into the composite fiber, etc. are promoted. Thus, the treatment can be performed promptly, a good swelling feeling is imparted to the entire fiber, and the sizing agent and the like dropped from the fiber, the cloth, etc. can be prevented from reattaching. Nonionic surfactants at that time include, for example, polyoxyethylene polyhydric alcohol alkyl esters, polyoxyethylene alkyl ethers, polyethylene glycol alkyl esters, etc., and anionic surfactants such as soap,
Examples thereof include higher alcohol-based surfactants. When the alkali treatment temperature is 100 ° C. or higher, a polyethylene glycol / polypropylene oxide adduct type surfactant is preferable from the viewpoint of foaming property.

Then, a composite fiber comprising the copolyester (A) and the fiber-forming polymer (B) or the fiber-forming polymer (C), a yarn using the fiber at least in part, or a fiber thereof By subjecting a fabric made of yarn or yarn to alkali treatment as described above, a fiber, yarn or fabric having a soft, excellent texture, surface condition and appearance similar to natural fiber is treated with conventional alkali treatment of this kind. Compared to technology,
It can be efficiently manufactured in an extremely short time.

The fibers, yarns or cloths obtained by the method of the present invention are various textile products such as women's clothing, underwear, coats, sports clothing and the like, which are required to have a soft texture. Very suitable for use in.

[0064]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Intrinsic viscosity [η] of the polymer, measurement of the alkali weight loss ratio of the cloth, alkali dissolution of the copolyester (A) and the fiber-forming polymer (B) or the fiber-forming polymer (C) in the examples The evaluation of the speed ratio, the degree of division and separation of the cloth after the alkali treatment, the feeling and the color tone was performed as follows.

Intrinsic viscosity [η] of the polymer : 0.25 g / dl, 0.50 g / dl and 1.0 g / dl of the target polymer were prepared using an equal weight mixed solvent of phenol and tetrachloroethane. It was determined from the reduced viscosities of three species measured at a temperature of 30 ° C. for solutions of different concentrations.

Alkaline weight loss of fabric : The woven and knitted fabric was deoiled, treated with hot water at 98 ° C. for 30 minutes, and then dried under reduced pressure of 1 mmHg at 70 ° C. for 8 hours under reduced pressure. After performing a predetermined alkali treatment, neutralize with acetic acid or sulfuric acid, wash with water,
Vacuum drying was performed under the above conditions. When the absolute dry weight after drying before alkali treatment is A and the absolute dry weight after drying after alkali treatment is B, the weight loss rate is shown by the following formula.

[0067]

[Formula 2] Weight loss rate (%) = {(A−B) / A} × 100

Alkaline dissolution rate ratio : Copolymerized polyester (A), fiber-forming polymer (B) and fiber-forming polymer (C) were spun and stretched under the same conditions by a conventional method to obtain 75 denier 24 A multifilament of filaments was obtained. A tubular sample was knitted using the obtained multifilament, relaxed and scoured by an ordinary method, and air-dried to obtain a measurement sample. Each measurement sample was immersed in a 20 g / liter sodium hydroxide aqueous solution at 98 ° C. under a bath ratio of 1: 500, the sample was dissolved with stirring, and an alkali dissolution rate constant K was calculated for each sample by the following formula. Then, the ratio was calculated.

[0069]

## EQU3 ## K = (10-R ^1/2 ) × {r ₀ / (10t)} where K = alkali dissolution rate constant (cm / sec) R = insoluble component after immersion in an alkaline aqueous solution for t seconds % By Weight r ₀ = Radius of Fiber Immediately after Immersion in Alkaline Aqueous Solution (t = 0) t = Dip Time in Alkaline Aqueous Solution (sec) where r ₀ = (dr / π · f · ρ · 9000) ^{1 / 2} dr = denier of yarn ρ = specific gravity of yarn (= 1.388) f = number of filaments of yarn

Degree of split peeling : Weft yarns constituting the woven fabric after alkali treatment were collected and observed with a peeling optical microscope on the composite surface of the composite fibers constituting the weft yarns, and the evaluations shown in Table 1 below were obtained. The degree of divided peeling was evaluated according to the standard.

[0071]

[Table 1] Evaluation criteria for the degree of divided peeling of fabric after alkali treatment ⊚: 90% or more of the composite fiber causes split peeling between the two polymers ○: 70 to 90% of the composite fiber causes split peeling between the two polymers Δ: of the composite fiber Split peeling between two polymers occurs at 50 to 70% x: Split peeling between two polymers occurs only at 50% or less of the composite fiber.

Fabric texture after alkali treatment : Table 2 below
The texture of the texture after the treatment was evaluated according to the evaluation criteria shown in.

[0073]

[Table 2] Evaluation criteria for the texture of fabric after alkali treatment ⊚: Extremely soft and has a good touch, but extremely good feel ○: Good, despite having a soft feel, Δ: Insufficient softness, slightly Moist texture X: Remarkably lacking in softness, moist and extremely poor texture

Color tone of fabric after alkali treatment and dyeing :
The texture of the texture after the treatment was evaluated according to the evaluation criteria shown in Table 3 below.

[0075]

[Table 3] Evaluation criteria for color tone of cloth after alkali treatment and dyeing ⊚: Color tone is extremely clear and deep, and has a very good appearance ○: Color tone is clear and slightly deep, and has a good appearance Δ: Specular reflection peculiar to polyester is reduced, but poor appearance ×: Color tone Extremely poor appearance with no depth

Examples 1 to 3 and Comparative Examples 1 to 6 Terephthalic acid and ethylene glycol were placed in an esterification reactor and the esterification reaction was carried out for 2 hours at 280 ° C. and a pressure of 2.5 kg / cm ² . After that, it was transferred to a polycondenser, and a predetermined amount of dimethyl 5-sodium sulfoisophthalate was added,
After reacting at 240 ° C., 350 ppm of antimony trioxide, polyethylene glycol having a molecular weight of 2000 and the following formula (V);

[0077]

[Chemical 13] The polyoxyethylene glycidyl ether represented by
It was added in the amounts shown in Table 5 below.

Further, with respect to the total amount of polyethylene glycol and polyoxyethylene glycidyl ether, 5% by weight of 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)- 1,3,5-Triazine-2,4,6- (1H, 3H, 5H) -trione (manufactured by American Cyanamid Co .; Syanox 1
790) and the temperature is increased from 240 ° C to 280 ° C 4
The pressure was gradually reduced to 0.1 mmHg while raising the temperature over 5 minutes, and then the melt viscosity of the system at 280 ° C. was 0.7.
The polycondensation reaction was continued until the melt viscosity of polyethylene terephthalate (dl / g) at 280 ° C. was substantially matched to produce the corresponding copolyesters (A).

Copolyester (A) produced above
And polyethylene terephthalate (intrinsic viscosity [η] = 0.60) (hereinafter referred to as “PET”) were melt-composite spun at 290 ° C. at a weight ratio of copolyester (A): PET = 1: 2. A laminated composite filament yarn (50 denier / 24 filament) that is post-stretched to have 5 layers of copolymerized polyester (A) and 5 layers of PET having the cross-sectional shape shown in FIG. Was manufactured.

Using the above-prepared composite filament yarn as warp yarns and weft yarns, a 2/1 twill weave was prepared by a conventional method. This woven fabric was treated with a jet dyeing machine (manufactured by Texham Giken Co., Ltd.) for 40 minutes at 130 ° C. using an alkali treatment liquid shown in Table 4 below, and scouring / desizing and alkali weight reduction treatment were simultaneously performed. Then, the results shown in Table 5 below were obtained.

[0081]

[Table 4] Alkaline treatment liquid Sodium hydroxide 5 g / liter Detrol US-60 (manufactured by Meisei Chemical Co., Ltd.) 2 g / liter Bath ratio 30: 1

[0082]

[Table 5]

From the results in Table 5 above, the dicarboxylic acid unit
Examples 1 to 3 using the composite fiber of the copolymer polyester (A) obtained by copolymerizing (I), the diol unit (II) and the side chain unit (III) in the above-mentioned content ratio of the present invention and PET. In this case, a fabric excellent in spinnability during the production of the conjugate fiber, having a high weight loss rate due to the alkali in the copolyester (A) portion, having a large degree of divided release, and having an excellent soft feeling can be obtained by the alkali treatment. Comparative Example 1 lacking any of the above requirements in the present invention
In the case of 6, it can be seen that the composite fiber of the copolyester (A) and PET cannot be manufactured with good processability, or that a fabric having a small alkali weight loss ratio and a small degree of divided peeling and having no soft feeling can be obtained by the alkali treatment. .

Example 4 Using the composite filament yarn produced in the above Example 3 as the warp yarn and the weft yarn, a 1/1 plain weave fabric was produced by a conventional method. Using the same jet dyeing machine as in Example 1 of this fabric, a bath ratio of 50: 1 containing sodium hydroxide in the proportions shown in Table 6 below and containing Detrol US-60 at 2 g / l. Using the alkaline treatment liquid, at the temperature shown in Table 6 for 20 minutes,
When the scouring, desizing and alkali reduction treatment were carried out simultaneously, the results shown in Table 6 were obtained.

[0085]

[Table 6]

From the results of Table 6 above, in order to obtain a treated fabric rich in softness by using an alkaline treatment liquid containing a strong alkaline substance alone, the concentration of the strong alkaline substance (sodium hydroxide) in the alkaline treatment liquid and It can be seen that it is necessary to adjust the treatment time to the above-mentioned appropriate range so that the alkali weight loss rate and the split exfoliation degree are within the appropriate ranges.

Example 5 Using the composite filament yarn produced in the above Example 1 as the warp yarn and the weft yarn, a 1/1 plain weave fabric was produced by a conventional method. Using the same jet dyeing machine as in Example 1 of this fabric, a bath ratio of 50: 1 containing sodium silicate in the proportions given in Table 7 below and containing 2 g / l of Detrol US-60. 60 minutes using the alkaline treatment liquid at the temperature shown in Table 7,
When the scouring, desizing and alkali reduction treatment were carried out simultaneously, the results shown in Table 7 were obtained.

[0088]

[Table 7]

From the results of Table 7 above, in order to obtain a treated fabric having a soft feeling by using an alkaline treatment liquid containing a weak alkaline substance alone, the concentration of the weak alkaline substance (sodium silicate) in the alkaline treatment liquid and the It can be seen that it is necessary to adjust the treatment time to the above-mentioned appropriate range so that the alkali weight loss rate and the split exfoliation degree are within the appropriate ranges.

<Example 6> The proportion of 5-sodium sulfoisophthalic acid unit was 5 mol%, the proportion of polyethylene glycol having a molecular weight of 2000 was 6% by weight, and the following formula (VI);

[0091]

[Chemical 14] A copolyester (A) was produced in the same manner as in Example 1 except that the proportion of the side chain unit (III) from the polyoxyethylene glycidyl ether represented by was adjusted to 6% by weight.

Copolyester (A) produced above
1 and a PET (intrinsic viscosity [η] = 0.60) melt-composite spinning at 290 ° C. at a weight ratio of copolyester (A): PET = 1: 4, and then stretched to obtain the product of FIG. A composite filament yarn (50 denier / 24 filament) having the cross-sectional shape shown in (d) was produced.

Using the above-prepared composite filament yarn as the warp yarn and the weft yarn, a 1/1 plain weave fabric was produced by a conventional method. Using the jet dyeing machine used in Example 1, this fabric was treated with the alkaline treatment liquids shown in Table 8 below.
When the treatment was carried out at 10 ° C. for 20 minutes to carry out the scouring, desizing and alkali reduction treatment at the same time, the results shown in Table 9 below were obtained.

[0094]

[Table 8] Alkaline treatment liquid Potassium hydroxide As shown in Table 9 Sodium carbonate As shown in Table 9 Detrol US-60 2g / l Bath ratio 50: 1

[0095]

[Table 9]

From the results in Table 9 above, when the alkali treatment is carried out using the alkali treatment liquid containing both the strong alkaline substance and the weak alkaline substance, in order to obtain a treated fabric rich in soft feeling, the alkali treatment liquid is used. It is necessary to adjust the concentration of the strong alkaline substance (potassium hydroxide) and the weak alkaline substance (sodium carbonate) in the above range to the above-mentioned appropriate ranges so that the alkali weight loss rate and the split exfoliation degree are within the appropriate ranges. I understand.

Example 7 Terephthalic acid and ethylene glycol were charged into an esterification reactor at 230 ° C.
The esterification reaction was carried out for 2 hours under a pressure of 2.5 kg / cm ² . Next, dimethyl 5-sodium sulfoisophthalate was added to the reaction product so as to be 2.5 mol% with respect to the total acid components and reacted, and then transferred to a polycondensation reactor preheated to 230 ° C. , To which the formula: HO (CH ₂ CH ₂
O) Polyethylene glycol represented by ₄₅ H and polyoxyethylene glycidyl ether represented by the above formula (V) in an amount of 8% by weight of each of the finally obtained copolyester (A). Was added.

Further, with respect to the total amount of polyethylene glycol and polyoxyethylene glycidyl ether, 5% by weight of 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)- 1,3,5-Triazine-2,4,6- (1H, 3H, 5H) -trione and 350 ppm of antimony trioxide were added to raise the temperature of the polycondensation reaction system from 230 ° C to 280 ° C over 45 minutes. While heating, the pressure was gradually reduced to 0.1 mmHg, and then the melt viscosity of the system at 280 ° C had an intrinsic viscosity of 0.7 dl / g.
The polycondensation reaction was continued until the melt viscosity of the polyethylene terephthalate (1) at 280 ° C. was substantially matched to produce a copolyester (A).

Polyethylene terephthalate (intrinsic viscosity [η] = 0.68) (hereinafter referred to as “PET (B)”) was used as the fiber-forming polymer (B) and the above-prepared copolymer polyester (A). 50:50 with PET (B)
Copolymerized polyester (A) and PET used in a weight ratio of
(B) forms a sheath portion randomly mixed with the same, and as the fiber-forming polymer (C), the same intrinsic viscosity [η] as above.
= 0.68 polyethylene terephthalate (hereinafter "PE
T (C) ”) is used as the core component C, and the spinning apparatus shown in FIG. 3 is used to produce a composite fiber having a cross-sectional shape shown in FIG.

More specifically, the melt flow of the copolyester (A) and the melt flow of PET (B) which form the sheath component are supplied to the spinneret pack of the spinning device at a weight ratio of 50:50 and mixed. Through a static mixer S of 8 elements made by Kenix Co., Ltd. provided on the plate 1, the composite is divided into random layers and guided as a sheath component to the periphery of the spinning hole 7 through the flow path 4 of the distribution plate 2, while melted PET. (C) is introduced into the central portion of the spinning hole 7 as the core portion C via the flow paths 5 and 6, and at that time, sheath component: core component = 5
The weight ratio was 0:50, and it was discharged from a spinning hole 7 having a round hole of 24 holes (the spinneret temperature of 290 ° C.), wound at a winding speed of 1000 m / min, and cross-sectioned as shown in FIG. A composite filament raw yarn in which a core portion made of PET (C) having a shape is surrounded by a sheath portion in which the copolyester (A) and PET (B) are randomly mixed is produced, and this is produced by a conventional method. It was drawn to obtain a drawn yarn of 75 denier / 24 filament. The alkali dissolution rate ratio between the copolyester (A) and PET (B) or PET (C) in this drawn yarn was about 250.

Using the drawn yarn produced above as warp yarns and weft yarns, a 1/1 plain woven fabric was prepared by a conventional method, and this woven fabric was desalted, scoured, relaxed, and
Pre-set at 0 ° C. Then, NaOH: 30 g at 90 ° C. using an aqueous solution of sodium hydroxide of 20 g / liter
%, And dyeing was performed under the dyeing conditions shown in Table 10 below.

[0102]

[Table 10] Dyeing condition dyeing method : Dye: Dianix Red BN-SE (CI Disperse Red 12) 5% owf Dispersion aid: Disper TL (manufactured by Meisei Chemical Industry Co., Ltd.) 1 g / l pH adjuster: ammonium sulfate 1 g / l acetic acid (48 %) 1 cc / liter Bath ratio: 1:30 Temperature: 120 ° C. Time: 60 minutes Reductive washing : Hydrosulfide 1 g / liter Amylazine (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1 g / liter NaOH 1 g / liter Bath ratio: 1:30 Temperature : 80 ° C Time: 20 minutes

The texture and color tone of the plain woven fabric obtained after the alkali treatment and dyeing were evaluated according to the above-mentioned evaluation criteria. As shown in Table 11 below, it was soft and supple and had a good peach skin tone. It had a good texture and had an extremely good color tone.

<Examples 8 to 9> The ratio of the copolyester (A): PET (B) constituting the sheath portion was 30:70 (Example 8) and 70:30 (Example 9), respectively.
Example 7 was repeated except that The results are shown in Table 1.
Shown in 1.

Example 10 The same operation as in Example 7 was carried out except that the number of static mixer elements in the mixing plate 1 of the spinneret pack was changed to 4, and the results shown in Table 11 were obtained.

Examples 11 to 12 Composite ratio of sheath portion and core portion: {copolymerized polyester (A) + PET
(B)}: PET (C) was changed to 70:30 (Example 11) and 30:70 (Example 12), respectively. The results are shown in Table 11.

<< Examples 13 to 16 >> The composite morphology and cross-sectional shape of the composite fiber are shown in FIG.
3), (X) (Example 14), (S) (Example 15) and (S) (Example 16) were performed in the same manner as in Example 7. The results are shown in Table 11.

Examples 17 to 20 As the copolyester (A), polyethylene glycol represented by the formula: HO (CH ₂ CH ₂ O) ₄₅ H and polyoxyethylene represented by the above formula (V) are used. The same procedure as in Example 7 was carried out except that the copolymerization ratio of glycidyl ether was changed as shown in Table 11 below. The results are shown in Table 11.

Example 21 As a side chain component in the copolyester (A), instead of the polyoxyethylene glycidyl ether represented by the formula (V), the following formula (VII);

[0110]

[Chemical 15]

When the same procedure as in Example 7 was carried out except that the compound represented by the formula (11) was used, the results shown in Table 11 were obtained.

Example 22 As a polyethylene glycol component in the copolyester (A), a formula;
Except for using those represented by _{HO (CH 2 CH 2 O)} 20 H was carried out in the same manner as in Example 7. The results are shown in Table 11.

Examples 23 to 24 As the fiber-forming polymer (B) constituting a part of the sheath portion, 5-sodium sulfoisophthalic acid was used in an amount of 1 relative to all acid components instead of PET (B). Example 7 was repeated except that 0.5 mol% copolymerized polyethylene terephthalate (Example 23) and polybutylene terephthalate (Example 24) were used, respectively. The results are shown in Table 11.

[0114]

[Table 11]

From the results of Table 11 above, Example 7 of the present invention
In any of the above cases, the composite fiber can be obtained with good processability of fiberizing, and the alkali-treated and dyed fabric having a soft texture of peach skin tone and excellent color tone can be obtained by the alkali treatment. I understand.

Comparative Examples 7 to 13 As shown in Table 12 below, the dicarboxylic acid unit represented by the above formula (I) and the formula (II ) And a formula (II
A polyester which does not contain at least one of the side chain units represented by I) or has a content ratio outside the scope of the present invention was used, and otherwise the same as in Example 7. However, the results were as shown in Table 12.

[0117]

[Table 12]

From the results of Comparative Examples 8 to 10 in Table 12 above,
When a polyester which does not contain at least one of the dicarboxylic acid unit of the formula (I), the diol unit of the formula (II) and the side chain unit of the formula (III) is used as the alkali-soluble component,
Although the processability in producing the conjugate fiber is good, its alkali solubility is not sufficient, the resulting alkali-treated fabric lacks in softness, is moist and has poor texture, and is a dyed product thereof. It can be seen that the color tone is inferior.
Further, from the results of Comparative Examples 11 to 13, the ratio of the dicarboxylic acid unit of the formula (I), the diol unit of the formula (II) and the side chain unit of the formula (III) in the copolyester (A) was found to be the same as that of the present invention. It is understood that if it is out of the range, the fiberizing processability becomes poor and the composite fiber as the alkali-treating raw yarn cannot be obtained.

Example 25 Terephthalic acid 971.5
g and 750 g of ethylene glycol were charged into an esterification reactor, and the esterification reaction was carried out at 230 ° C. under a pressure of 2.5 kg / cm ² for 2 hours. Then, the obtained reaction product is transferred to a polycondensation reactor which has been heated to 230 ° C. in advance,
5-sodium dimethyl sulfoisophthalate 40.2g
Was added to react and then the formula: HO (CH ₂
CH ₂ O) ₄₅ H and a polyoxyethylene glycidyl ether represented by the above formula (V) were added.

Furthermore, 5% by weight of 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) -based on the total amount of polyethylene glycol and polyoxyethylene glycidyl ether was used. 1,3,5-triazine-2,4,6- (1H, 3H, 5H) -trione and 0.4 g of antimony trioxide and phosphorous acid of 0.
12 g was added to prepare a polycondensation reaction system. The temperature of the polycondensation reaction system was raised from 230 ° C. to 280 ° C. over 45 minutes while gradually reducing the pressure to 0.1 mmHg, and thereafter 28
The polycondensation reaction is continued until the melt viscosity of the system at 0 ° C. almost coincides with the melt viscosity at 280 ° C. of polyethylene terephthalate having an intrinsic viscosity of 0.70 dl / g and is used as a sea component in the sea-island type composite fiber. A polymerized polyester (A) was produced.

Using dimethyl terephthalate containing 1.7 mol% of dimethyl 5-sodium sulfoisophthalate as a dicarboxylic acid component and ethylene glycol, polymerization was carried out according to a conventional method by a transesterification method to form a sea-island type composite fiber. A polyester [polyester (B)] having an intrinsic viscosity [η] of 0.60 used as the island component in Example 1 was produced.

Copolyester (A) produced above
The polyester (B) and polyester (B) are supplied to a spinning device for producing sea-island type composite fibers at a weight ratio of 50:50, and the spinneret temperature is 2
A sea-island type having a transverse cross-sectional shape shown in (g) of FIG. 1, which has a sea part made of the copolyester (A) and an island part made of the polyester (B) after being spun at 95 ° C. and a take-up speed of 700 m / min. A spun raw yarn (255 denier / 24 filament) composed of a composite fiber (40 islands) was obtained. The alkali dissolution rate ratio between the copolyester (A) and the polyester (B) in this composite fiber was 30. Next, the obtained spun raw yarn was drawn at a draw ratio of 3.4 using a heating roller at a temperature of 75 ° C., and then drawn at 130 ° C.
A heat treatment was carried out at a temperature of 1 to produce a drawn yarn of 75 denier / 24 filament.

After using the drawn yarn produced above as a weft yarn and a single yarn of polyester (B) of 75 denier / 24 filaments as a warp yarn, a satin fabric having many weft yarns on its surface was prepared, and then NaOH: 20 g / liter When it was dipped in the sodium hydroxide aqueous solution of No. 3 at 98 ° C. for 15 minutes for alkali treatment, the sea component was completely dissolved and removed. Then, the obtained alkali-treated fabric is desized by a conventional method,
After scouring and presetting, dyeing was performed under the dyeing conditions shown in Table 13 below.

[0124]

[Table 13] Dyeing conditions Cationic dyeing bath composition : Kayacryl Red GRL-ED (Nippon Kayaku) 2% owf sodium sulfate 3 g / l acetic acid 1% owf sodium acetate 0.5% owf EDTA 0.1 g / l bath ratio: 1:50 temperature : 120 ℃ Time: 40 minutes

In the obtained alkali-treated dyed woven fabric, the weft yarns appearing on the woven fabric surface are ultrafine fibers having a single fiber fineness of 0.1 denier or less, and are supple, corresponding to ⊚ in Table 2 above. It was very soft and had a very good peach skin tone, and it was dyed in a clear, deep and good red color corresponding to ⊚ in Table 3 above. Instead of the polyester (B), polyethylene terephthalate having an intrinsic viscosity [η] of 0.60 was used to obtain a spun yarn composed of sea-island type composite fiber, and stretched to prepare a similar woven fabric. The fabric was treated and dyed with a disperse dye,
The color clarity was slightly inferior.

Example 26 In place of 5-sodium sulfoisophthalic acid, 44.4 g of dimethyl 5-sodium sulfoisophthalate was used, and 1,3,5-tris (4-t-butyl-3-hydroxy-) was used. 2,6-Dimethylbenzyl) -1,3,5-triazine-2,4,6-
Instead of (1H, 3H, 5H) -trione, an equal weight of penaeerythryl-tetrakis [3- (3,5-
Di-t-butyl-4-hydroxyphenyl) propionate] (“Irganox 101” manufactured by Ciba Geigy)
A copolymerized polyester (A) for sea component was produced in the same manner as in Example 25 except that 0) was used.

Copolyester (A) produced above
Using the same polyester (B) as used in Example 25, spinning, drawing, weaving, alkali treatment and dyeing were performed in the same manner as in Example 25. In addition, this Example 26
The alkali dissolution rate ratio of the copolyester (A) and the polyester (B) in the composite fiber of was 30.
As a result, as in Example 25, the evaluations of the texture and the color tone both corresponded to ⊚ in Tables 2 and 3, and the texture was extremely supple, extremely soft, and had excellent elasticity, and the coloring property was excellent. A woven fabric consisting of ultrafine fibers dyed in high red was obtained.

Comparative Example 14 The procedure of Example 25 was repeated except that the polyoxyethylene glycidyl ether represented by the formula (V) was not used in the production of the copolyester as the sea component. A copolyester for the component was prepared. Using this copolymerized polyester and the same polyester (B) as used in Example 25, spinning, drawing, weaving, alkali treatment and dyeing were performed in the same manner as in Example 25. The alkali dissolution rate ratio of the copolyester for sea component and the polyester (B) in the composite fiber of Comparative Example 14 was 10.
As a result, alkali treatment at 98 ° C. for 60 minutes was required to completely dissolve and remove the sea component, and as a result, the alkali amount was reduced even to the island portion made of polyester (B), and the obtained alkali-treated fabric was obtained. Had extremely low strength and was not stiff and could not be put to practical use.

COMPARATIVE EXAMPLE 15 In Example 25, a compound of formula: HO (C
A copolymerized polyester for sea components was produced in the same manner as in Example 25 except that polyethylene glycol represented by (H ₂ CH ₂ O) ₄₅ H was not used. Using this copolymerized polyester and the same polyester (B) as used in Example 25, spinning, drawing, weaving,
Alkali treatment and dyeing were performed. Incidentally, this comparative example 1
In the composite fiber of No. 5, the alkali dissolution rate ratio between the copolyester for sea component and the polyester (B) was 5. As a result, it took 98 ℃ to completely remove the sea components.
In this case, the alkali treatment for 40 minutes is required, and as a result, the alkali is reduced to the islands made of polyester (B), and the obtained alkali-treated woven fabric has extremely low strength and is not suitable for practical use. Met.

Comparative Example 16 Example 25 as a sea component
Using the polyester (B) produced in Example 1, and using polyethylene terephthalate having an intrinsic viscosity [η] of 0.70 as the island component, spinning, drawing, weaving, alkali treatment and dyeing were performed in the same manner as in Example 25. . The alkali dissolution rate ratio between the polyester (B) for sea component and polyethylene terephthalate in the composite fiber of Comparative Example 16 was 2. As a result, alkali treatment at 98 ° C. for 120 minutes or more is required to completely dissolve and remove the sea components, and as a result, not only the sea part made of polyester (B) but also most of the island parts made of polyethylene terephthalate are required. Since the alkali-reduced woven fabric had been alkali-reduced, the woven fabric could not retain its shape and could not be put to practical use.

Example 27 As copolymerized polyester (A), 2.5 mol% of 5-sodium sulfoisophthalic acid unit produced in the same manner as in Example 7 was used, and the formula:
It contains 5% by weight of polyethylene glycol represented by HO (CH ₂ CH ₂ O) ₄₅ H and 5% by weight of polyoxyethylene glycidyl ether represented by the above formula (V), and has an intrinsic viscosity [η] of 0.65. Was used. Further, in the same manner as in Example 25, a polyester [polyester (B)] containing 1.7 mol% of 5-sodium sulfoisophthalic acid unit and having an intrinsic viscosity [η] of 0.67 was produced.

The above copolymerized polyester (A) and polyester (B) were applied to a spinning device for producing super flat composite fibers.
Supplied at a weight ratio of 0:70, spun at a spinneret temperature of 295 ° C. and a take-up speed of 1000 m / min, and has an 11-division bonding structure having a cross-sectional structure shown in FIG. A spun raw yarn (170 denier / 24 filament) of flat composite fiber was obtained. Then, the obtained spun raw yarn was drawn at a drawing temperature of 75 ° C. and a heat setting temperature of 120 ° C. at a draw ratio of 2.25 times to produce a drawn yarn of 75 denier / 24 filament. In this drawn yarn, the alkali dissolution rate ratio of the copolyester (A) and the polyester (B) was about 100.

The stretched yarn obtained above was knitted into a cylinder and 10
After relaxing at 0 ° C. for 20 minutes, heat setting was performed at 180 ° C. for 1 minute, and immersion in an aqueous sodium hydroxide solution of NaOH: 20 g / liter at 75 ° C. for 30 minutes was performed for alkali weight reduction processing. When observing the state of the yarn at this time,
The copolyester (A) portion is completely dissolved and removed, and the super flat fiber shown in FIG. 4D, in which the polyester (B) layers are completely divided and independent from each other, is obtained. W was 30. This alkali-treated knitted fabric was dyed in the same manner as in Example 25.
As shown in No. 4, it was supple, extremely soft, and had a very excellent feeling of elasticity, and it was dyed in the above-mentioned vivid and deep red color.

Examples 28 to 30 5-Sodium sulfoisophthalic acid unit, formula: HO (CH ₂ CH ₂ O) ₄₅ H
The unit of the polyethylene glycol represented by the formula (A) and the unit of the unit comprising the polyoxyethylene glycidyl ether represented by the formula (V) have the copolymerization ratios shown in Table 14 below. The production, drawing, knitting, alkali treatment and dyed fiber of the super-flat composite fiber were carried out in the same manner as in Example 27 except that the above) was used, and the results shown in Table 14 below were obtained.

Comparative Examples 17 to 21 As shown in Table 14 below, 5-sodium sulfoisophthalic acid unit,
Formulated with a polyester that does not contain at least one unit consisting of polyethylene glycol represented by the formula: HO (CH ₂ CH ₂ O) ₄₅ H and unit consisting of polyoxyethylene glycidyl ether represented by the above formula (V). Example 27
In the same manner as in Example 27 except that the copolymerized polyester (A) was used, the production and stretching of super-flat composite fibers were performed.
When knitting, alkali treatment and dyed fiber were performed, the results shown in Table 14 below were obtained.

<Examples 31 to 32> As the polyester (B), a polyester obtained by copolymerizing 2.5 mol% of 5-sodium sulfoisophthalic acid unit is used (Example 31) or 5-sodium sulfoisophthalic acid unit. The production, drawing, knitting, alkali treatment and dyed fiber of super-flat composite fiber were carried out in the same manner as in Example 27 except that polyethylene terephthalate containing no (Example 32) was used, and the results are shown in Table 14 below. We got the following results.

<Examples 33 to 34> A super flat composite having a 7-divided laminating structure having a cross-sectional structure shown in FIG. 4 (a) from the copolyester (A) and the polyester (B). Fiber spinning yarn (200 denier / 24
(Filament) (Example 33) or a super-flat composite fiber spinning raw yarn (200 denier / 24 filament) having a five-division type laminating structure having a cross-sectional structure shown in (c) of FIG. 4 (Example 34) ) Was produced and the super flat composite fiber was produced, stretched, knitted, treated with alkali and dyed in the same manner as in Example 27 except that the super flat composite fiber was used. We got the following results.

[0138]

[Table 14]

From the results in Table 14 above, 5-sodium sulfoisophthalic acid unit, formula: HO (CH ₂ CH ₂ O) ₄₅ H
Within the scope of the present invention containing a unit composed of polyethylene glycol represented by the formula (1) and a unit composed of the polyoxyethylene glycidyl ether represented by the above formula (V) within the scope of the present invention, and other fiber-forming polymers. Combined (B)
In the case of Examples 27 to 34 in which the cloth made of super flat composite fibers with [polyester (B)] is treated with alkali,
In each case, only the copolyester (A) is selectively and rapidly dissolved and removed, and the supple, soft and rich texture is made of the super-flat fibers of the fiber-forming polymer (B) [polyester (B)]. It can be seen that an alkali-treated dyed fabric which is good and has an excellent color tone can be obtained.

On the other hand, 5-sodium sulfoisophthalic acid unit, a unit consisting of polyethylene glycol represented by the formula: HO (CH ₂ CH ₂ O) ₄₅ H and polyoxyethylene represented by the above formula (V). When a fabric of a composite fiber using a polyester or a copolyester lacking at least one unit consisting of glycidyl ether as an alkali-soluble component is subjected to alkali treatment, it lacks flexibility and is poor in color tone. It can be seen that only dyed fabric can be obtained.

[0141]

The dicarboxylic acid unit partially containing the dicarboxylic acid unit represented by the above formula (I); the diol unit represented by the above formula (II); and the diol unit represented by the above formula (III) A conjugate fiber comprising a copolyester (A) having a side chain unit having the above-mentioned specific ratio and another fiber-forming polymer (B), and an alkali treatment using a yarn or a cloth produced from the conjugate fiber. In the case of carrying out, at least a part of the copolyester (A) can be rapidly treated in a very short time under mild alkaline treatment conditions without causing erosion, dissolution, damage, etc. of the fiber-forming polymer (B). By dissolving and removing, it is possible to efficiently produce fibers, yarns and cloths having a soft, supple and extremely excellent texture, surface condition and appearance similar to natural fibers in a short time.

In addition, the composite fiber composed of the copolyester (A) and the fiber-forming polymer (B) has a good processability at the time of fiberizing, and can be smoothly processed without causing yarn breakage or fuzzing. It can be manufactured.

Since the copolyester (A) in the conjugate fiber used in the present invention has an extremely high alkali solubility, the present invention allows the isophthalic acid having a sulfonate group, which has been conventionally used as an alkali-soluble component, to be copolymerized. The resulting polyester can be used as the fiber-forming polymer (B) which remains after the alkali treatment, and the resulting alkali-treated fiber or fabric has an increased dyeability with a cationic dye due to the presence of a sulfonate group.
It is possible to obtain a clear and deep good dyed product.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a composite form in a cross section of a composite fiber of the present invention.

FIG. 2 is a diagram showing another example of the composite form in the cross section of the composite fiber of the present invention and the form after the alkali treatment.

FIG. 3 is a diagram showing an example of a spinneret pack used for producing the composite fiber of FIG.

FIG. 4 is a diagram showing still another example of the composite form in the cross section of the composite fiber of the present invention and the form after the alkali treatment.

[Explanation of symbols]

 A Copolyester (A) B Fiber-forming polymer (B) C Fiber-forming polymer (C) 1 Mixing plate 2 Distribution plate 3 Base plate 4 Channel 5 Channel 6 Channel 7 Spinning hole

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location D01F 8/14 B 7199-3B D06N 3/00 8016-4F (72) Inventor Hidefumi Nagata Kurashiki, Okayama Prefecture 1621 Sakazu City, Kuraray Co., Ltd. (72) Inventor Isao Tokunaga 1621 Sakazu City, Kurashiki City, Okayama Prefecture (72) Inventor Izumi Wataya 1621 Sakazu City, Kurashiki City, Okayama Prefecture (72) Inventor Takao Akagi 1621 Sakata, Kurashiki City, Okayama Prefecture Kuraray Co., Ltd. (72) Masao Kawamoto 1621 Sakata, Kurashiki City, Okayama Prefecture Kuraray Co., Ltd.

Claims (2)

[Claims] 1. (A) (a) The following formula (I); (In the formula, Ar represents a trivalent aromatic group and M represents a metal atom.)
A dicarboxylic acid unit partially containing a dicarboxylic acid unit represented by: (b) the following formula (II): embedded image —O— (R ¹ —O) _m — (II) (wherein R ¹ Is an alkylene group, m is a number from 10 to 100), and (c) the following formula (III); (In the formula, R ² is an alkylene group, R ³ is a hydrocarbon group having 1 to 18 carbon atoms, n is a number of 10 to 100, and x and y each represent 0 or 1); A dicarboxylic acid unit represented by the formula (I), wherein the dicarboxylic acid unit represented by the formula (I) is 0.5 to 10 mol% of all acid components constituting the copolymerized polyester, and a diol unit represented by the formula (II). And 1 to 49% by weight of the side chain unit represented by the formula (III), respectively, based on the weight of the copolyester, and
A copolymerized polyester in which the total content of diol units represented by (II) and side chain units represented by formula (III) is 2 to 50% by weight based on the weight of the copolymerized polyester; and (B) At least one other fiber-forming polymer; 2. (A) (a) The following formula (I); (In the formula, Ar represents a trivalent aromatic group and M represents a metal atom.)
A dicarboxylic acid unit partially containing a dicarboxylic acid unit represented by: (b) the following formula (II): embedded image —O— (R ¹ —O) _m — (II) (wherein R ¹ Is an alkylene group and m is a number of 10 to 100); and (c) the following formula (III); (In the formula, R ² is an alkylene group, R ³ is a hydrocarbon group having 1 to 18 carbon atoms, n is a number of 10 to 100, and x and y each represent 0 or 1); A dicarboxylic acid unit represented by the formula (I), wherein the dicarboxylic acid unit represented by the formula (I) is 0.5 to 10 mol% of all acid components constituting the copolymerized polyester, and a diol unit represented by the formula (II). And 1 to 49% by weight of the side chain unit represented by the formula (III), respectively, based on the weight of the copolyester, and
A copolymerized polyester in which the total content of diol units represented by (II) and side chain units represented by formula (III) is 2 to 50% by weight based on the weight of the copolymerized polyester; and (B) The above-mentioned copolyester (A), which is obtained by subjecting a conjugate fiber comprising at least one kind of other fiber-forming polymer; a yarn or a cloth produced by using the conjugate fiber to an alkali treatment,
A method for producing a fiber, a thread or a fabric, which comprises dissolving and removing at least a part thereof.