JPH0892816A - Modified polyester fiber - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a polyester fiber having good alkali hydrolysis resistance, and excellent color development and melt stability. [Structure] A polyester fiber containing terephthalic acid as a main acid component and cyclohexanedimethanol as a main diol component, wherein 0 to 40 mol% of all dicarboxylic acid components constituting the polyester are other than terephthalic acid. It is replaced by the dicarboxylic acid component (A), and 0 to 30 mol% of the diol component constituting the polyester is a diol component (B) other than cyclohexane dimethanol.
And the total amount of the dicarboxylic acid component (A) and the diol component (B) is in the range of 5 to 40 mol% of the total dicarboxylic acid component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber which has good alkali hydrolysis resistance, does not deteriorate in hydrolysis resistance even when dyed with a cationic dye, and has excellent color developability and melt stability. .

[0002]

2. Description of the Related Art Polyester fibers, especially polyethylene terephthalate fibers, are highly crystalline and have a high melting point, so that they have excellent heat resistance and chemical resistance as well as mechanical properties such as strength and elongation. It exhibits performance and is widely used in the fields of industrial materials and clothing. However, it is known that polyethylene terephthalate fibers are hydrolyzed in an aqueous alkaline solution, resulting in erosion of the fiber surface. As a fiber for clothing, it is also known to reversely utilize this phenomenon and subject the woven or knitted fabric to alkali weight reduction treatment in order to impart a silky soft and good feeling. Also,
Polyethylene terephthalate fiber is inferior in dyeability, and dyes other than disperse dyes are difficult to dye, so that the field of use of the fiber is narrowed. Many improvements and modification methods have been proposed in order to improve such defects of dyeability. As a typical method thereof, (a) a method of incorporating a metal sulfonate group-containing compound into polyester (Japanese Patent Publication No. 34-10497 and Japanese Patent Publication No. 49-33766), and (b) an amino group-containing compound to polyester (Japanese Patent Publication No. 54-38)
159).

However, even if a fiber which can be dyed with a cationic dye by modifying the polyethylene terephthalate in this way (hereinafter referred to as a cationic dye-dyeable polyester fiber) is used, as described above, When the alkali weight-reducing treatment is applied to the woven or knitted fabric to impart a silky soft and good texture, the fibers are almost decomposed, and there is a problem that the effect of modifying the dye is lost.

Furthermore, in applications where the woven or knitted product is exposed to an aqueous alkaline solution during the manufacturing process or during the use of the woven or knitted product,
The above-mentioned cationic dye-dyeable polyester fiber may cause a marked decrease in strength and may be unusable.
For example, in the mercerizing process performed on cotton fabric, gloss is imparted by treating with a high concentration of alkali, but it is a mixed fabric of cationic dye-dyeable polyester fiber and cotton. When the same treatment is applied, the strength is remarkably reduced. Various proposals have been made to solve the drawbacks of the cationic dye-dyeable polyester fiber against alkali. As a typical method,
A method in which an m-metal sulfobenzoic acid compound or the like is polymerized at the molecular chain end of polyester (Japanese Patent Publication No. 19228/1990), and a method in which a metal sulfonaphthalenedicarboxylic acid compound is copolymerized with polyester (JP-A-5-106115).
Issue).

However, even though the former method has a sufficient effect of improving the alkali resistance, when the polyester fiber is dyed with a cationic dye, the dye is completely adsorbed, but the compound containing the metal sulfonate group is adsorbed. Compared with the polyester fiber containing only, the dyeability is poor, the vividness of the color is impaired, and it is difficult to obtain a deep color. In the latter method, the alkali resistance was not satisfactory even when the dyeability, the color vividness and the like were at the same level as compared with the polyester fiber containing only the metal sulfonate group-containing compound. .

Further, a method has been proposed in which a sulfoisophthalic acid type cationic dye dyeing agent is used in an amount less than the usual amount (JP-A-59-53774, JP-B-3-14951). . However, simply reducing the amount of the sulfoisophthalic acid-based cationic dye-dyeing agent is not enough to improve the alkali resistance, and the woven or knitted knitted fabric of the cationic dye-dyeable polyester fiber and the regular-polyester fiber is insufficient. When the cloth is subjected to an alkali weight reduction treatment, not only the treatment cannot withstand the treatment but also the dyeability when dyed with a cationic dye is remarkably deteriorated, resulting in a problem that the sharpness of color is impaired.

The alkali resistance of the cationic dye-dyeable polyester fiber treated by the above-mentioned various methods is improved as compared with the conventional cationic dye-dyeable fiber, but it is sufficient as compared with the polyethylene terephthalate fiber. is not.

On the other hand, utilizing the property that the cationic dye-dyeable polyester is easily dissolved in alkali,
Polyethylene terephthalate remains as a residual component, and polyethylene terephthalate copolymerized with 5-sodium sulfoisophthalic acid as an alkali-soluble component is treated with an alkaline aqueous solution to dissolve and remove the dissolved component. A method for producing ultrafine fibers, split fibers, modified cross-section fibers and the like made of polyethylene terephthalate is also known. However, there is a problem that the fiber single yarn becomes thin, the surface area per unit weight becomes large due to division and deformation, and as a result, the ratio of surface reflection of the fiber becomes high and the appearance becomes whitish, and there is a deep hue. It was difficult to obtain ultrafine fibers, split fibers, modified cross-section fibers, etc. In this case, it is possible to use a polyester modified with 5-sodium sulfoisophthalic acid as the residual component to make the dye deeper by dyeing with a cationic dye. However, due to the modification, the rate of alkali dissolution of the polyester as the residual component is increased. Therefore, there is a problem that selective dissolution of dissolved components becomes difficult.

On the other hand, a polyester having terephthalic acid and cyclohexanedimethanol as main components is known as a polyester having excellent hydrolysis resistance (J. Ap.
pl.Polym.Sci., 27, p4807, 1982, J.Appl.Polym.Sci.,
37, p1019, 1989). However, since the polyester has a high melting point of 295 ° C., the melting temperature during spinning becomes a high temperature of 300 ° C. or higher, and there is a problem that deterioration due to thermal decomposition during melting is unavoidable, and operational stability during fiber production. There is a drawback. When such a polyester is used as a molding material, measures such as addition of a stabilizer typified by an organophosphorus compound and copolymerization of a third component such as isophthalic acid in order to lower the melting point are taken. Is not enough. Therefore, the present situation is to take measures to prevent thermal decomposition even by controlling the molding conditions such as shortening the melt residence time during molding.

Further, since the polyester has a high glass transition temperature and high crystallinity, it has poor dyeability as compared with polyethylene terephthalate, and when dyed with a disperse dye under the same conditions, polyethylene terephthalate -There is a problem that it is difficult to dye as compared with G-fiber.

[0011]

SUMMARY OF THE INVENTION In view of the above situation, the object of the present invention is to provide good alkali hydrolysis resistance,
Another object of the present invention is to provide a polyester fiber having excellent color developability and melt stability. This feature can be applied not only to single fibers but also to composite fibers containing the polyester as one component.

[0012]

According to the present invention, the above object is a polyester fiber containing terephthalic acid as a main acid component and cyclohexanedimethanol as a main diol component. 0 to 40 mol% of all the constituent dicarboxylic acid components are replaced by a dicarboxylic acid component (A) other than terephthalic acid, and 0 to 30 mol% of the diol component constituting the polyester is cyclohexanedimethano- Other than diole component (B), and the total amount of dicarboxylic acid component (A) and diole component (B) is in the range of 5 to 40 mol% of all dicarboxylic acid components. Is achieved by providing a modified polyester fiber characterized by:

The polyester in the present invention is a polyester having terephthalic acid as a main dicarboxylic acid component and cyclohexane dimethanol as a main diol component. Cyclohexane dimethanol used as the main diol component includes 1,2-cyclohexane dimethanol, 1,3-cyclohexane dimethanol,
There are three types of positional isomers of 1,4-cyclohexanedimethanol, and one of them may be used, or a mixture of two or more types may be used. The positional isomer is not particularly limited, but 1,4-cyclohexanedimethanol is particularly preferable. Further, each position isomer has cis and trans stereoisomers, and either one of them or a mixture thereof may be used.

The "dicarboxylic acid (A) other than terephthalic acid" in the present invention is not particularly limited, but isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, 4,4 '
-Diphenyl ether dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 4,4'-diphenyl isopropylidene dicarboxylic acid, 1,2-diphenoxyethane-4 ', 4''-dicarboxylic acid, anthracene dicarboxylic acid Aromatic dicarboxylic acids such as 2,5-pyridinedicarboxylic acid and diphenylketone dicarboxylic acid; aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, azelaic acid and sebacic acid; decalin dicarboxylic acid and cyclohexanedicarboxylic acid Examples thereof include alicyclic dicarboxylic acid. Not only one such dicarboxylic acid,
You may use 2 or more types.

In particular, when cyclohexanedicarboxylic acid is used as the dicarboxylic acid (A), sufficient crystallinity is maintained even when the copolymerization amount is increased to lower the melting point of the polyester, while the decrease in glass transition temperature is minimized. Since it can be kept at the limit, it is suitable as the dicarboxylic acid (A). Cyclohexanedicarboxylic acid includes 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid,
There are three types of positional isomers of 1,4-cyclohexanedicarboxylic acid, and one of them may be used, or two or more of them may be used and are not particularly limited. Further, each position isomer also has cis and trans stereoisomers, and either one of them or a mixture thereof may be used. When 1,2-cyclohexanedicarboxylic acid is used, its anhydride, hexahydrophthalic anhydride, may be used.

When isophthalic acid is used as the dicarboxylic acid component (A), sufficient crystallinity is maintained even when the copolymerization amount is increased and the melting point is lowered, while the decrease in glass transition temperature is minimized. It is suitable as the dicarboxylic acid (A) because it can be maintained and the cost is low.

The copolymerization amount of the above-mentioned dicarboxylic acid component (A) is in the range of 0 to 40 mol%, particularly 0 to 35 mol% based on the total dicarboxylic acid components constituting the polyester. When the amount of the copolymerization exceeds 40 mol%, the melting point and crystallinity of the polyester are lowered, and as a result, the heat shrinkage rate of the polyester fiber is increased, and the like, so that the polyester fiber is usually demanded. It becomes impossible to have heat resistance.

In the present invention, "diol component (B) other than cyclohexanedimethanol" means ethylene glycol, propanediol, hexanediol, neopentyl glycol, diethylene glycol, polyethylene glycol. -Aliphatic diols such as -hydroquinone, catechol-
Aromatic diol such as ethylene oxide adduct of bisphenol, resorcin, naphthalene diol, bisphenol A, bisphenol A, bisphenol S, bisphenol S; norbornane dimethanol
And alicyclic diols such as tricyclodecane dimethanol and decalin dimethanol. These diols may be copolymerized with one kind or two or more kinds.

The copolymerization amount of the above-mentioned diol component (B) is 0 to 30 with respect to the total diol components constituting the polyester.
It is in the range of mol%, especially in the range of 0 to 25 mol%. When the copolymerization amount exceeds 30 mol%, the alkali hydrolysis resistance of the polyester becomes insufficient.

The total copolymerization amount of the above-mentioned dicarboxylic acid component (A) and diol component (B) is in the range of 5 to 40 mol%, particularly 10 to 35 mol%. When the total copolymerization amount exceeds 40 mol%, the melting point of polyester,
The crystallinity decreases, and as a result, the heat shrinkage rate of the polyester fiber becomes large, and the heat resistance normally required for the polyester fiber cannot be obtained. On the other hand, when the total amount of copolymerization is less than 5 mol%, the melting point of the polyester is high, the melting temperature during spinning is too high, the fibers are likely to be colored and decomposed, and there is a problem in stability of the spinning process. Occurs.

In the present invention, the dicarboxylic acid component (A)
Although the diol component (B) has been described in detail, a sulfonate group-containing compound can be mentioned as these components. Examples of the sulfonate group-containing compound include compounds represented by the following formulas (1) and / or (2).

[Chemical 1] (In the formula, X ₁ is an ester-forming functional group, X ₂ is the same or different from X ₁ as an ester-forming functional group or a hydrogen atom, Ar is a trivalent aromatic group, and M is a metal atom.)

[Chemical 2] (In the formula, X ′ ₁ is an ester-forming functional group, and X ′ ₂ is X ′.
_An ester-forming functional group or a hydrogen atom which is the same as or different from ₁ , Ar 'is a trivalent aromatic group, R ₁ R ₂ R ₃ R ₄ is an alkyl group, the same or different group selected from an aryl group, m Indicates a positive integer. )

Ar in the formula (1) and Ar 'in the formula (2) represent trivalent aromatic groups, and are 1,3,5-benzenetriyl group and 1,3,6-benzenetriyl group. Benzenetriyl groups such as 1,2,4-benzenetriyl group; 1,3,6
-Naphthalenetriyl group, 1,3,7-naphthalenetriyl group, 1,4,5-naphthalenetriyl group, 1,4
Examples thereof include a naphthalenetriyl group such as a 6-naphthalenetriyl group. Further, in the formula (1), M represents a metal atom, and alkali metals such as lithium, sodium and potassium are preferable.

As the sulfonate group-containing compound represented by the formula (1), 5-sodium sulfoisophthalic acid, 5-sodium
Sodium sulfoisophthalic acid dimethyl ester, 5-
Sodium sulfoisophthalic acid diethyl ester, 5-
Potassium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid dimethyl ester, 5-potassium sulfoisophthalic acid diethyl ester, 5-lithium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid dimethyl ester, 5-lithium sulfoisophthalic acid diethyl ester, 2- Metal sulfonated benzenedicarboxylic acid such as sodium sulfoisophthalate or its lower alkyl ester, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid dimethyl ester, 6-sodium Metal sulfonated naphthalenedicarboxylic acid such as sulfo-1,4-naphthalenedicarboxylic acid, 5-sodium sulfo-1,4-naphthalenedicarboxylic acid or a lower alkyl ester thereof And the like.

As the sulfonate group-containing compound represented by the formula (2), 3,5-dicarboxybenzenesulfonic acid tetrabutylphosphonium salt, 3,5-dicarboxybenzenesulfonic acid ethyltributylphosphonium salt,
3,5-Dicarboxybenzenesulfonic acid benzyltributylphosphonium salt, 3,5-dicarboxybenzenesulfonic acid phenyltributylphosphonium salt, 3,5
-Dicarboxybenzenesulfonic acid tetraphenylphosphonium salt, 3,5-dicarboxybenzenesulfonic acid butyltriphenylphosphonium salt, 3,5-dicarboxybenzenesulfonic acid benzyltriphenylphosphonium salt, 3,5-dicarbomethoxybenzene Sulfonic acid tetrabutylphosphonium salt, 3,5-dicarbomethoxybenzenesulfonic acid ethyltributylphosphonium salt,
3,5-Carboxybenzenesulfonic acid tetraphenylphosphonium salt and the like can be mentioned.

Since these sulfonate group-containing compounds are components that can be copolymerized in order to make the above-mentioned polyester fiber dyeable with a cationic dye, the copolymerization amount of the carboxylic acid group-containing compound is the dicarboxylic acid component of the polyester. It is preferably 1 mol% or more. The upper limit of the copolymerization amount of the sulfonate group-containing compound is not particularly limited, but it is preferably 5 mol% or less in consideration of the thickening action of the polymer due to the addition of the compound. It is particularly preferably in the range of 1.5 to 3 mol%. When the copolymerization amount of the sulfonate group-containing compound is less than 1 mol%, the dyeability with a cationic dye becomes insufficient, while when the copolymerization amount exceeds 5 mol%, the fiber properties of the polyester fiber are improved. May be significantly reduced, and the alkali hydrolysis resistance may be significantly reduced. In addition, the number of seats for dyeing with the cationic dye increases, so that the amount of dyeing on the fiber increases, and the vividness of the color may be lost.

As described above, the total copolymerization amount of the dicarboxylic acid component (A) and the diol component (B) is in the range of 5 to 40 mol%, but the sulfonic acid group-containing compound is added to the dicarboxylic acid component (A). ) Or diol component (B), and other dicarboxylic acid component (A) or diol
The total amount of copolymerization can be set to 5 to 40 mol% by using the component (B) together.

The polyester in the present invention can be copolymerized with the third component within the range not impairing the object of the present invention. Examples of the third component include hydroxycarboxylic acids such as β-hydroxyethoxybenzoic acid, p-oxybenzoic acid, hydroxypropionic acid and hydroxyacrylic acid; or hydroxycarboxylic acids derived from ester-forming derivatives thereof, ε-caprolactone. And other aliphatic lactones. These third
Not only one kind of component but also two or more kinds can be used.

Further, in the polyester of the present invention, a polyvalent carboxylic acid such as trimellitic acid, trimesic acid, pyromellitic acid and tricarballylic acid within a range where the polyester is substantially linear; glycerin and trimethylolethane. , Trimethylolpropane, pentaerythritol and the like may be contained.

The polyester of the present invention preferably has an intrinsic viscosity (measured at 30 ° C. using a mixed solvent having a weight ratio of phenol / tetrachloroethane at 30 ° C.) of 0.4 to 1.5.

The polyester of the present invention is subjected to an esterification or transesterification reaction using cyclohexanedimethanol and diol components (B) as raw material components, terephthalic acid and dicarboxylic acid components (A), After adjusting the low polymer, tetraalkoxy titanium,
A polycondensation reaction is performed under reduced pressure at 230 to 300 ° C. using a polycondensation catalyst such as antimony oxide or germanium oxide to adjust the viscosity to a desired value. In addition, after the polymerization is performed in the liquid phase as described above, the degree of polymerization may be further increased by solid phase polymerization to increase the intrinsic viscosity.

It is not necessary to employ a special method for fiberizing the thus obtained polyester, and a normal melt-spinning method of polyester fibers is used. The spun fiber may be a solid fiber having no hollow portion or a hollow fiber having a hollow portion. Further, the cross-sectional shape of the fiber to be spun is not limited to a circular shape, and may be a polygon such as a tri-octagon, a multilobe such as tri-octa, a T-shape, a U-shape or the like. .

The polyester fiber thus obtained may be subjected to stretching heat treatment or false twisting, if necessary, and then
Alternatively, it can be dyed after being made into a cloth. The cloth thus obtained can be used in various applications such as industrial materials and clothing. In particular, it is particularly useful in applications where it is exposed to alkali during the manufacturing process or during practical use.

Although the polyester of the present invention can be used as a single fiber, it can be combined with another polymer to form a composite fiber, and the effect of alkali hydrolysis resistance of the polyester can be further exerted. For example, a core-sheath type composite fiber using polyethylene terephthalate as the core component and the polyester of the present invention as the sheath component,
Even under alkaline treatment conditions, the strength of the polyethylene terephthalate as the core component does not decrease and the fiber strength can be maintained. When the composite morphology of the composite fiber is sea-island type, by subjecting the sea component to polyethylene terephthalate and the island component to the polyester of the present invention and subjecting to alkali treatment, ultrafine fibers made of the polyester are obtained. Further, when a fiber of a composite form in which polyethylene terephthalate and the polyester of the present invention are laminated alternately in layers is subjected to an alkali treatment, a split type fiber of polyethylene terephthalate fiber and a fiber made of the polyester is obtained. can get. In addition to this, various forms of fibers can be obtained by subjecting the composite form to various treatments and subjecting to alkali treatment.

In the above-mentioned conjugate fiber, the polymer which can be compounded with the polyester of the present invention is a polymer which is more hydrolyzable by alkali than the polyester.
In addition to polyethylene terephthalate, polyethylene terephthalate in which the above-mentioned sulfonate group-containing compound is copolymerized in a proportion of 10 mol% or less and polyethylene in which polyalkylene glycol is copolymerized are preferable. Examples thereof include terephthalate.

The alkali treatment method is not particularly limited, but generally, it can be heated with a strong alkaline aqueous solution such as sodium hydroxide, if necessary.

In the polyester fiber of the present invention, substances generally added to the fiber, ultraviolet absorbers, optical brighteners, matting agents, antistatic agents, flame retardants, flame retarding auxiliaries, lubricants, plasticizers Agents and the like can be added.

The polyester fiber of the present invention has a good alkali hydrolysis resistance, and even if a sulfonate group-containing compound is copolymerized to make it cationic dyeable, the alkali hydrolysis resistance is hardly reduced. . Further, by utilizing the alkali hydrolysis resistance of the polyester, it is possible to obtain a fiber having various forms and functions by subjecting the composite fiber composed of the polyester and another polymer to alkali treatment.

[0038]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In addition, each physical-property value in an Example was measured by the following method. (1) Content (mol%) of Monomer Introduced into Polyester Molecules The content was determined based on the 1H-NMR measurement results of polyesters using deuterated trifluoroacetic acid as a solvent. (2) Intrinsic viscosity of polyester (dl / g) It was measured at 30 ° C. using a mixed solvent having a weight ratio of phenol / tetrachloroethane. (3) Glass transition temperature (Tg ° C.) of polyester Based on JIS K 7121, it was measured at a temperature rising rate of 10 ° C./min using a differential scanning calorimeter (TC-10A type manufactured by Metra Co.). (4) Melting point of polyester (Tm ° C.), crystallinity (ΔH
J / g) The sample chip was heat-treated at 140 ° C. for 18 hours in a nitrogen stream to crystallize, and then the sample was scanned with a differential scanning calorimeter (Metra, T).
C-10A type), the temperature was raised at 10 ° C./minute, and the peak of crystal melting (° C.) was observed, and the calorific value (J / g) was used.

(5) Strength (g / d) and Elongation (%) of Polyester Fiber It was determined in accordance with JIS L 1013. (6) Hot water shrinkage rate (Wsr%) of polyester fiber A mark of 50 cm interval is marked on the sample under an initial load of 1 mg / d,
Then, the sample was placed in hot water of 98 ° C. under a load of 5 mg / d for 30 minutes.
It was left for a minute, then taken out, and the interval L ₁ (cm) between the marks was measured under a load of 1 mg / d, and calculated by the following formula. Wsr (%) = [(50−L ₁ ) / 50] × 100 (7) Dry heat shrinkage rate (Dsr%) of polyester fiber A sample is marked at 50 cm intervals under an initial load of 1 mg / d.
Then, the sample was placed in a dry heat atmosphere heated to 180 ° C for 5 m.
Leave for 10 minutes under a load of g / d, and then take it out for 1 m.
The distance L ₂ (cm) between the marks was measured under a load of g / d and calculated by the following formula. Dsr (%) = [(50−L ₂ ) / 50] × 100 (8) Alkaline dissolution rate ratio of polyester fiber Polyester is spun and drawn to obtain a multifilament of 75 denier / 36 filaments. The sample was made into a cylindrical knitted sample using a conventional method, relaxed and refined by a conventional method, and air-dried to obtain a measurement sample. 98 ° C, 20
The measurement sample was immersed in a sodium hydroxide aqueous solution of g / liter at a bath ratio of 1: 500, the sample was dissolved with stirring, and the alkali dissolution rate constant K was calculated by the following formula.
Was calculated. K = (10−R ^1/2 ) × (r ₀ / 10t) K: Alkali solubility constant (cm / sec) R: Insoluble component weight% after t seconds immersion in alkaline aqueous solution r ₀ : Immediately after immersion in alkaline aqueous solution ( t = 0) Fiber diameter (cm) t: Alkaline aqueous solution immersion time (sec) where r ₀ = (dr / π · f · ρ · 900,000)
^1/2 dr: fineness of yarn (denier) f: number of filaments of yarn ρ: specific gravity of yarn (calculated as 1.2 here)

Example 1 A dicarboxylic acid raw material consisting of 30 mol% of 1,4-cyclohexanedicarboxylic acid (cis / trans = 55/45) and 70 mol% of terephthalic acid, and 1,4-cyclohexanedimethanol (cis / Trans = 32/68), the molar ratio of diol raw material: dicarboxylic acid raw material is 1.
The slurry was adjusted to 2: 1 to form a slurry, and the slurry was heated under pressure (absolute pressure 2.5 Kg / cm ² ) at a temperature of 2
An esterification reaction was carried out at 50 ° C. until the esterification rate reached 95% to produce a low polymer. Next, as a catalyst, 35
0 ppm of tetraisopropyl titanate was added, and melt polycondensation was performed at 280 ° C. for 1.5 hours under a reduced pressure of 1 torr absolute pressure to produce a polyester having an intrinsic viscosity of 0.75 dl / g. This polyester is extruded from a nozzle in a strand shape and cut into a diameter of 2.8 mm and a length of 3.2 m.
m columnar chips were produced. This chip is 1H-NM
When analyzed by R, 1, out of all dicarboxylic acid units,
It was confirmed that 30 mol% of 4-cyclohexanedicarboxylic acid units were copolymerized. Furthermore, the Tg of this chip was 72 ° C., the Tm was 236 ° C., and the ΔH was 30 J / g.

The above polyester chip was crystallized at 180 ° C. under vacuum, and a spinning nozzle with 36 circular spinning holes having a diameter of 0.25 mm was used to spin at a spinning speed of 1000.
Unstretched yarn was obtained by spinning at 275 ° C. at m / min. This was subjected to a drawing heat treatment at a drawing speed of 1000 m / min using a heating roller of 75 ° C. and a plate heater of 150 ° C. to obtain a drawn yarn of 75 denier / 36 filaments. The obtained drawn yarn has a strength of 4.0 g / d and an elongation of 32.
%, Wsr was 13%, and Dsr was 17%. This polyester fiber had no problem in process passability even when it was formed into a fiber for a long time. A tubular knitted fabric was prepared using this filament. The alkali solubility rate ratio measured using this tubular knitted fabric was calculated. The results are shown in Tables 1 and 2.

Examples 2 to 9 The same procedure as in Example 1 was repeated except that 5-sodium sulfoisophthalic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid and ethylene glycol were copolymerized in the proportions shown in Table 1. To polymerize the polyester. Table 1 shows the physical properties of each polyester. Using each of the obtained polyesters, spinning and drawing were performed in the same manner as in Example 1.
Table 2 shows the physical properties of the obtained drawn yarn. A tubular knitted fabric was prepared using the drawn yarn, and an alkali dissolution rate ratio was calculated. All the polyester fibers had good processability.

Comparative Example 1 Polyester was polymerized in the same manner as in Example 1 except that 1,4-cyclohexanedicarboxylic acid was not copolymerized. Table 1 shows the physical properties of the obtained polyester. Since the crystallization rate was high, Tg could not be measured and Tm was as high as 295 ° C. An attempt was made to perform spinning using this polyester, but since the Tm was high, the spinning temperature had to be as high as 310 ° C., the polyester failed to melt, and thermal decomposition of the polyester was observed. Since the fiber could be obtained for the time being, its physical properties were measured and shown in Table 2.

Comparative Examples 2 to 4 Similar to Example 1 except that 1,4-cyclohexanedicarboxylic acid, ethylene glycol and 5-sodium sulfoisophthalic acid were copolymerized in the proportions shown in Table 1. Then, the polyester was polymerized. Table 1 shows the physical properties of the obtained polyester. Using each of the obtained polyesters, spinning and drawing were performed in the same manner as in Example 1.
Table 2 shows the physical properties of the obtained drawn yarn. A tubular knitted fabric was prepared using the drawn yarn, and an alkali dissolution rate ratio was calculated. The drawn yarn obtained in Comparative Example 2 had large Wsr and Dsr and was inferior in heat resistance. The drawn yarn obtained in Comparative Example 3 also had large Wsr and Dsr, was inferior in heat resistance, and had a faster alkali dissolution rate ratio than the yarns obtained in Examples. The polyester obtained in Comparative Example 4 has Tm
Since the spinning temperature was high, the spinning temperature was high, the polyester melted poorly, and the thermal decomposition of the polyester was observed.

Reference Examples 1 to 4 In Example 1, as the polyester, polyethylene terephthalate (Reference Example 1), 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate (Reference Example 2), polybutylene terephthalate -G (Reference Example 3), 5-
Spinning and drawing were carried out in the same manner except that sodium sulfoisophthalate copolymerized polybutylene terephthalate (Reference Example 4) was used to obtain drawn yarn. A tubular knitted fabric was produced using this drawn yarn, and the alkali dissolution rate ratio was determined. Table 2 shows the results. It can be seen that the drawn yarns obtained in the examples have a very low alkali dissolution rate ratio, that is, a very low hydrolyzability with respect to alkali.

Example 10 The polyester prepared in Example 8 was used as the island component and 5
Sea-island type composite fiber (sea: island = 1: 1, weight ratio) using polyethylene terephthalate (intrinsic viscosity 0.55) copolymerized with 3 mol% of sodium sulfoisophthalic acid as a sea component
Was subjected to composite spinning at a melting temperature of 280 ° C. to obtain a drawn yarn. The obtained drawn yarn has a strength of 3.0 g / d and an elongation of 28.
%, Wsr was 18%, and Dsr was 21%. A tubular knitted fabric was prepared using this drawn yarn and immersed in a 20 g / liter sodium hydroxide aqueous solution at 90 ° C. for 15 minutes to remove sea components. The alkali weight loss rate was 52%, and it was found that the sea component polymer was completely removed.
The ultrafine fibers thus obtained were dyed with a cationic dye under the following dyeing conditions. Dyeing conditions: Dye Kayacryl Brill Pink B-ED (manufactured by Nippon Kayaku Co., Ltd.) 2.0% owf sodium sulfate 2 g / liter acetic acid 1.0% owf sodium acetate 0.5% owf EDTA 0.1 g / liter Bath ratio 1: 50 temperature 120 ° C. time 40 minutes The dyed product had a clear and deep color tone.

Comparative Example 9 Sea island using polyethylene terephthalate (intrinsic viscosity 0.68) as an island component and polyethylene terephthalate (intrinsic viscosity) obtained by copolymerizing 3 mol% of 5-sodium sulfoisophthalic acid as an ocean component Type composite fiber (sea: island = 1: 1, weight ratio)
Was subjected to composite spinning at a melting temperature of 280 ° C. to obtain a drawn yarn. The obtained drawn yarn has a strength of 3.3 g / d and an elongation of 22.
%, Wsr was 16%, and Dsr was 19%. A tubular knitted fabric was prepared using this drawn yarn and immersed in a 20 g / liter sodium hydroxide aqueous solution at 90 ° C. for 15 minutes to remove sea components. The alkali weight loss rate was 58%, indicating that not only the sea component polymer was completely removed, but also the island component had some weight loss.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

EFFECTS OF THE INVENTION According to the present invention, there is provided a polyester fiber which is excellent in alkali hydrolysis resistance, color development and melt stability. Further, it is also possible to obtain fibers having various cross-sectional shapes by forming a composite fiber containing one component of polyester constituting the polyester fiber and subjecting it to alkali treatment.

Claims (1)

[Claims] 1. A polyester fiber comprising terephthalic acid as a main acid component and cyclohexanedimethanol as a main diol component, wherein 0 to 40 mol% of all dicarboxylic acid components constituting the polyester is terephthalic acid. Other than dicarboxylic acid component (A) other than 0 to 30 mol% of the diol component constituting the polyester
Is replaced by a diol component (B) other than cyclohexanedimethanol, and the total amount of the dicarboxylic acid component (A) and the diol component (B) is 5 to 40 mol% of the total dicarboxylic acid component. The modified polyester fiber is characterized in that