JP2013018802A - Polyester resin composition, method for producing the same, polyester fiber composed of the same, and fiber product of the polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin composition capable of obtaining polyester fiber with high quality such as an excellent color tone and excellent glossiness by taking specific measures in a polymerization process to stabilize operability in a fiber spinning and drawing process and following treatment processes.SOLUTION: In the polyester resin composition, a polyester resin having principal repeating units consisting of ethylene terephthalate includes particles, which are formed of an alkaline earth metal carboxylate and a phosphoric acid ester and have an average particle diameter of 0.01-3 μm, and germanium oxide to satisfy following expressions: (a) 100≤M1≤500; (b) 0.5×M1≤P≤1.5×M1; (c) 20≤G≤150 where M1, P and G respectively represent a content (ppm) of alkaline earth metal atoms, a content (ppm) of phosphorus atoms, and a content (ppm) of germanium atoms for the obtained polyester resin composition.

Description

  The present invention relates to a polyester resin composition suitable for polyester fibers that can be dyed with a cationic dye at normal pressure as well as a disperse dye, a method for producing the resin composition, and a modified cross-section or a fine shape using the resin composition. Dispersion consisting of polyester fiber containing fineness and a textile product using the polyester fiber, made of a polyester resin composition that gives stable operability, such as yarn-making properties and passability in post-processing steps, and is particularly excellent in color tone The present invention relates to a polyester product that can be dyed with a dye or a cationic dye and a fiber product using the same.

  Polyester fibers, particularly polyethylene terephthalate fibers, are excellent in heat resistance, chemical resistance, mechanical properties, and the like, and are therefore widely used in clothing and industrial applications. However, on the other hand, since the fiber structure is strong, dyeing usually has to be performed under high temperature and high pressure.

  Therefore, many methods for improving the dyeability by modifying the polyester polymer have been proposed for the purpose of improving the dyeability of the polyester fiber. For example, Japanese Patent Publication No. 34-010497 (Patent Document 1) and the like are known in which a 5-sodium sulfoisophthalic acid component is copolymerized with polyester to enable dyeing with a cationic dye.

  In addition to cationic dyeable components such as 5-sodium sulfoisophthalic acid component, a polyester fiber that can be dyed to cationic dyes at normal pressure is also obtained by copolymerizing a third component such as adipic acid and isophthalic acid. It has been. For example, in Japanese Examined Patent Publication No. 57-032139 (Patent Document 2), by using a random copolymer type dicarboxylic acid as a copolymer component in addition to a metal sulfonate group-containing isophthalic acid, it is possible to perform atmospheric pressure dyeing on a cationic dye. Obtained polyester fiber. For example, in JP-A-08-269820 (Patent Document 3) and JP-A-61-239015 (Patent Document 4), a polymer obtained by copolymerizing a 5-sodium sulfoisophthalic acid component and an adipic acid component is spun. Shows that polyester fibers which can be dyed at normal pressure on disperse dyes and cationic dyes are obtained.

  On the other hand, with the diversification of consumer needs in recent years, the above-mentioned polyester fibers are subjected to yarn processing processes such as false twisting and interlace entanglement in response to market demands. It is manufactured. These fibers have a problem that thread breakage, fluff, and the like are generated due to friction with the metal surface during production, thereby reducing productivity and product value.

In order to solve these problems, it is usually fiberized using polyester added with titanium oxide (TiO ₂ ) as inorganic particles. Titanium oxide-added fibers have high lubricity on the fiber surface, so less trouble is caused by friction with the metal surface, but they are not used at all because they have high hiding power and lose the gloss of the product. Only a small amount is used for fibers that require a feeling. In particular, when the above modified polyester resin composition obtained by a direct polymerization method using terephthalic acid as a starting material via an esterification reaction is made into a fiber, even if titanium oxide having high lubricity is added, There was a problem that fuzz and thread breakage occurred frequently during the production, which lowered productivity and product value.

On the other hand, instead of adding inorganic particles to polyester as described above, an internal particle method has been proposed in which a calcium compound, a phosphorus compound, or the like is added during polyester synthesis to form fine particles. For example, according to Japanese Examined Patent Publication No. 49-013234 (Patent Document 5), a production method in which internal particles are formed from a specific metal compound and a phosphorus compound is proposed. Also,
According to Japanese Patent Laid-Open No. 59-126456 (Patent Document 6), a production method in which internal particles are formed with a boron compound, an alkali metal compound, and an alkaline earth metal compound is proposed. Japanese Patent Application Laid-Open No. 2004-300288 (Patent Document 7) proposes preventing an increase in the pressure of the spinning filter by limiting the particle diameter range of the internal particles.

Japanese Examined Patent Publication No. 34-01497 Japanese Patent Publication No.57-032139 Japanese Patent Laid-Open No. 08-269820 JP-A 61-239015 Japanese Patent Publication No.49-013234 JP 59-126456 A JP 2004-3000268 A

  The present inventors directly esterified terephthalic acid and ethylene glycol, and copolymerized 5-sodium sulfoisophthalic acid as a metal salt component of sulfoisophthalic acid and adipic acid as an aliphatic dicarboxylic acid through a polycondensation step. When making a polyester resin composition into a fiber, particularly when producing a modified cross-section yarn with a small single fiber fineness, paying attention to the problem of fluffing during drawing and lowering the quality, after performing a polycondensation reaction, 5 -The case where the internal particle method according to the above prior art was employed in the polymerization process of the polyester resin composition in which sodium sulfoisophthalic acid and adipic acid were copolymerized was examined in detail. The color tone of the polymer obtained by adopting the internal particle method according to this prior art is bad, and spinning during spinning, yarn breakage during stretching and pressurization of the spinning filter are remarkable, and fluff frequently occurs in the yarn processing process. There were many problems.

  As a result of further investigations to solve these problems, the present inventors have taken particular measures in the polymerization process, so that the operability of the spinning / drawing process and the subsequent post-processing process is stabilized, and an excellent color tone is obtained. Knows that it can provide polyester fibers that can be dyed with cationic dyes made of high-quality polyester resin compositions such as gloss and gloss. The inventors have found that the present invention can be applied to all polyester fibers that can be dyed with dyes, and have reached the present invention.

The basic composition of the polyester resin composition according to the present invention is:
An average particle size of 0.01% formed from an alkaline earth metal salt of a carboxylic acid and a phosphate ester so that the main repeating unit of the polyester resin composed of ethylene terephthalate satisfies the following formulas (a) to (c): The polyester resin composition comprises particles having a particle size of ˜3 μm and germanium oxide.
(A) 100 ≦ M1 ≦ 500
(B) 0.5 × M1 ≦ P ≦ 1.5 × M1
(C) 20 ≦ G ≦ 150
However, M1, P, and G represent the content (ppm) of alkaline earth metal atoms, the content (ppm) of phosphorus atoms, and the content (ppm) of germanium atoms, respectively, with respect to the finished polyester resin composition.

According to a preferred embodiment,
In order to satisfy the following formulas (a ′), (b ′) and (c), an average particle diameter of 0.01 to 0.01 formed from an alkali metal salt of a carboxylic acid or an alkali metal hydroxide and a phosphate ester It further contains 3 μm particles.
(A ′) 100 ≦ M1 + M2 ≦ 500
(B ′) 0.5 × (M1 + M2) ≦ P ≦ 1.5 × (M1 + M2)
(C) 20 ≦ G ≦ 150
However, M2 shows content (ppm) of an alkali metal atom with respect to the completed polyester resin composition, respectively.

As another preferred embodiment,
As the polyester resin, a polyester resin obtained by copolymerizing an alkali metal salt unit of sulfoisophthalic acid and an aliphatic dicarboxylic acid unit having 2 to 8 carbon atoms so as to satisfy the following formulas (d) and (e) is used.
(D) 0.8 ≦ S ≦ 5
(E) 2 ≦ A ≦ 15
However, S and A show the copolymerization rate (mol%) of the sulfoisophthalic acid unit in a polyester resin, and the copolymerization rate (mol%) of a C2-C8 aliphatic dicarboxylic acid, respectively.

According to yet another aspect,
As the polyester resin, a polyester resin obtained by copolymerizing an alkali metal salt unit of sulfoisophthalic acid and an aliphatic dicarboxylic acid unit having 2 to 8 carbon atoms so as to satisfy the following formulas (d) and (e) is used.
(D) 0.8 ≦ S ≦ 5
(E) 2 ≦ A ≦ 15
However, S and A show the copolymerization rate (mol%) of the sulfoisophthalic acid unit in a polyester resin, and the copolymerization rate (mol%) of a C2-C8 aliphatic dicarboxylic acid, respectively.

On the other hand, the basic composition of the method for producing a polyester resin composition according to the present invention is that the polyester oligomer of terephthalic acid and ethylene glycol contains alkaline earth metal atoms, phosphorus atoms and germanium atoms in the finished polyester resin composition. To a method for producing a polyester resin composition in which an alkaline earth metal salt of a carboxylic acid, a phosphate ester and a germanium oxide are added as additives so that the following formulas (a) to (c) are satisfied: is there.
(A) 100 ≦ M1 ≦ 500
(B) 0.5 × M1 ≦ P ≦ 1.5 × M1
(C) 20 ≦ G ≦ 150
However, M1, P, and G represent the content (ppm) of alkaline earth metal atoms, the content (ppm) of phosphorus atoms, and the content (ppm) of germanium atoms, respectively, with respect to the finished polyester resin composition.

According to a preferred embodiment of the invention relating to this production method, the content of the alkaline earth metal atom, phosphorus atom and germanium atom in the finished polyester resin composition is represented by the following formulas (a ′), (b ′) and (c): In order to satisfy the above, it is also included to add an alkali metal salt of a carboxylic acid or an alkali metal hydroxide as an additive.
(A ′) 100 ≦ M1 + M2 ≦ 500
(B ′) 0.5 × (M1 + M2) ≦ P ≦ 1.5 × (M1 + M2)
(C) 20 ≦ G ≦ 150
However, M2 has shown content (ppm) of the alkali metal atom with respect to the completed polyester resin composition.

According to another preferred embodiment,
An alkali metal salt of ethylene glycol ester of sulfoisophthalic acid and an aliphatic dicarboxylic acid having 2 to 8 carbon atoms may be added as monomers so as to satisfy the following formulas (d) and (e).
(D) 0.8 ≦ S ≦ 5
(E) 2 ≦ A ≦ 15
However, S and A show the copolymerization rate (mol%) of the sulfoisophthalic acid unit in a polyester resin, and the copolymerization rate (mol%) of a C2-C8 aliphatic dicarboxylic acid, respectively.

According to still another preferred embodiment,
An alkali metal salt of sulfoisophthalic acid ethylene glycol ester and an aliphatic dicarboxylic acid having 2 to 8 carbon atoms may be added as monomers so as to satisfy the following formulas (d) and (e).
(D) 0.8 ≦ S ≦ 5
(E) 2 ≦ A ≦ 15
However, S and A show the copolymerization rate (mol%) of the sulfoisophthalic acid unit in a polyester resin, and the copolymerization rate (mol%) of a C2-C8 aliphatic dicarboxylic acid, respectively.

In each of the above production methods, preferably, an additive and a monomer to be added are added to a polyester oligomer of terephthalic acid and ethylene glycol in advance by dissolving or dispersing in ethylene glycol.
It is preferable that the single fiber fineness of the polyester fiber of this invention which consists of a polyester resin composition obtained in this way is 0.6-3 dtex, and this polyester fiber is used for at least one part of a textile as a multifilament.

  The polyester resin composition of the present invention includes particles formed of a metal compound and a phosphate ester and germanium oxide in the polyester resin composition, and the germanium oxide provides uniform dispersibility of the particles. As a result, it provides excellent operability in the spinning / drawing step and the subsequent post-processing step, and is free from turbidity and coloring, and has a high-quality polyester resin composition and fiber, and a polyester resin composition capable of imparting cationic dyeability. Articles and fibers are provided.

Hereinafter, embodiments of the present invention will be described in detail.
≪Polyester resin whose main repeating unit is composed of ethylene terephthalate≫
The polyester resin in the polyester resin composition of the present invention requires that the main repeating unit is composed of ethylene terephthalate. This means that the copolymerization monomer may be contained up to 15 mol%.

The dicarboxylic acid monomer other than terephthalic acid of the polyester resin of the present invention is not particularly limited, but is an aliphatic dicarboxylic acid having a metal salt unit of sulfoisophthalic acid of 0.8 mol% to 5 mol% and having 2 to 8 carbon atoms. It is preferable to copolymerize 2 mol% or more and 15 mol% or less of acid units. This is expressed as follows.
(D) 0.8 ≦ S ≦ 5
(E) 2 ≦ A ≦ 15
However, S and A show the copolymerization rate (mol%) of the sulfoisophthalic acid unit in a polyester resin, and the copolymerization rate (mol%) of a C2-C8 aliphatic dicarboxylic acid, respectively.

When S is 0.8 mol% or more, there is no shortage of cationic dyeing seats, so the amount of dyeing does not decrease and the sharpness peculiar to cationic dyes does not become poor. Also, if S is 5 mol% or less, the polymer melt viscosity does not increase during polymerization, and a polymer having an appropriate degree of polymerization can be obtained. As a result, there is no problem that the fiber strength decreases. preferable. Examples of the metal salt of sulfoisophthalic acid include alkali metal salts of 5-sulfoisophthalic acid (lithium salt, sodium salt, potassium salt, rubidium salt, cesium salt) and the like. If necessary, alkaline earth salts such as magnesium salts and calcium salts of these compounds may be used in combination. Of these, the sodium salt of 5-sulfoisophthalic acid is most often used.

As the aliphatic dicarboxylic acid having 2 to 8 carbon atoms, succinic acid, glutaric acid, adipic acid, suberic acid, and sebacic acid are preferable, and adipic acid is particularly preferable. The use of adipic acid contributes to the improvement of dyeability because an appropriate disorder occurs in the amorphous structure of the fiber. When A is 2 mol% or more, the dyeability in atmospheric dyeing is maintained in an appropriate range. When A is 15 mol% or less, the glass transition temperature and melting point of the polyester resin are maintained in an appropriate range, and the mechanical properties, fastness, heat resistance, and the like necessary for the fiber product can be obtained.
The glycol monomer other than ethylene glycol forming the polyester resin is not particularly limited.
In the present invention, the polycondensation of the polyester resin may be performed by a known method comprising the following steps i to iii.

That is,
i Esterification process A slurry of terephthalic acid and ethylene glycol is continuously fed to an esterification reaction can containing bis (β-hydroxyethyl) terephthalate and polyester oligomer obtained by esterifying terephthalic acid with ethylene glycol. The polyester oligomer having an esterification reaction rate of about 95% is continuously obtained by reacting at a temperature of 250 ° C. for about 3 to 8 hours. This is transferred to a polycondensation reactor.

ii Addition step of polycondensation catalyst Add an ethylene glycol solution of polycondensation catalyst to this polycondensation reaction can, and add additives such as copolymerization monomer and coloring inhibitor (generally triethyl phosphate) as necessary. Add as ethylene glycol solution or dispersion.
At this time, it is preferable to add the additive and the monomer by dissolving or dispersing them in ethylene glycol in advance for uniform dispersion.

iii polycondensation step The polycondensation reaction is started by distilling off ethylene glycol (removing ethylene glycol under reduced pressure). The strands are discharged and converted into chips.

  In the present invention, the adipic acid component to be copolymerized can be added at any stage of synthesizing the polyester resin, but the method of adding adipic acid powder at the start of the esterification reaction of terephthalic acid and ethylene glycol and terephthalic acid A general method is to add a dispersion or solution of adipic acid or bis (2-hydroxy) adipate to bishydroxyethyl terephthalate obtained by an esterification reaction with ethylene glycol.

In addition, 5-sodium sulfoisophthalic acid powder can be added at any stage of polymer synthesis similar to adipic acid, and 5-sodium sulfoisophthalic acid powder at the start of esterification reaction of terephthalic acid and ethylene glycol. Dispersion of alkylene glycol esters such as dimethyl 5-sodium sulfoisophthalate and ethylene glycol ester of 5-sodium sulfoisophthalic acid in bishydroxyethyl terephthalate obtained by the esterification reaction of terephthalic acid and ethylene glycol The method of adding as a liquid or a solution is common. In addition, a small amount of additives such as matting agents, pigments, antioxidants, fluorescent whitening agents, antistatic agents, antibacterial agents, ultraviolet absorbers, light stabilizers, heat stabilizers are added to polyester resins as necessary. In addition, a flame retardant may be contained.

≪Alkaline earth metal salt of carboxylic acid≫
In the present invention, an alkaline earth metal salt of a carboxylic acid is used. Examples of alkaline earth metal salts of carboxylic acids include magnesium acetate, calcium acetate, magnesium oxalate, calcium propinate, calcium stearate, magnesium stearate, calcium benzoate, manganese acetate and the like.

  In particular, when a magnesium salt of carboxylic acid is used, the particle diameter of the particles formed in the polyester resin is relatively small, and as a result, the stability of the polyester fiber spinning process is improved, and the refractive index of the particles and the polyester are increased. Since the refractive index of the resin is close, the transparency of the polyester resin composition containing dispersed particles is preferable.

When an alkaline earth metal salt of acetic acid is used, it is preferable from the viewpoint of handleability and cost.
Therefore, magnesium acetate is most suitable as the alkaline earth metal salt of carboxylic acid.
In the present invention, the alkaline earth metal salt of carboxylic acid is preferably added to the polycondensation reaction can as an ethylene glycol solution, and the concentration of the solution is not particularly limited, but is preferably a concentration that allows complete dissolution.

<Particle>
An alkaline earth metal salt of carboxylic acid and a phosphoric acid ester described later are each added as an ethylene glycol solution to the polycondensation reaction can in the step of adding the ii polycondensation catalyst, and both are reacted to form particles. This reaction starts after both are added in the step of adding the ii polycondensation catalyst. Thereafter, as ethylene glycol is distilled off in the iii polycondensation step, the solubility of both reactants decreases, and the reactants precipitate as particles. Once precipitated, the particles may further aggregate as the polycondensation proceeds to form secondary particles.
In the present invention, these particles and secondary particles (hereinafter collectively referred to simply as “particles”) contribute to the stability of yarn production.

≪Average particle diameter≫
In the present invention, the average particle size of the particles is 0.01 μm or more and 3.0 μm or less. More preferably, it is 0.02 μm or more and 1.5 μm or less. If the average particle diameter is 0.01 μm or more, the particles are not too fine and the slipperiness and runnability of the fibers can be improved, which contributes to an improvement in process passability. In addition, if the average particle size is 3.0 μm or less, the filter for filtering the molten polymer is not clogged when spinning the polyester fiber, and the pressure increases or the yarn breaks. There is no decrease in permeability.

  The above has described the case of an alkaline earth metal salt of a carboxylic acid and a phosphate ester. However, in the present invention, the case of an alkali metal salt of a carboxylic acid and a phosphate ester, and the case of an alkali metal hydroxide and a phosphorus ester. The same applies to acid esters.

<< (a) 100≤M1≤500 >>
In the present invention, the content (M1) of the alkaline earth metal atom contained in the polyester resin composition as the alkaline earth metal salt of carboxylic acid needs to be 100 to 500 ppm, more preferably 100 to 300 ppm. It is. By setting M1 to 100 ppm or more, sufficient particles can be obtained to improve the stability of the polyester fiber spinning process. Since the generation of coarse particles can be suppressed by suppressing to 500 ppm or less, clogging of the filter for filtering the melted polyester resin composition during spinning does not occur, and the stability of the polyester fiber yarn production process is kept good. be able to.

≪Phosphate ester≫
As described above, the phosphate ester in the present invention reacts with the alkaline earth metal salt of carboxylic acid to form particles, and contributes to the stability of the polyester fiber spinning process. Although it is known to react with phosphoric acid, phosphorous acid, phosphonic acids, phosphinic acids, etc., phosphate esters are used in the present invention. The reason is that since the particle diameter of the particles is relatively small, the stability of the polyester fiber spinning process is improved, and the refractive index of the particles and the refractive index of the polyester resin are close to each other. Since the transparency of a resin composition becomes high, it is preferable. Of the phosphate esters, triethyl phosphate is most suitable. In the present invention, the phosphate ester is preferably added to the polycondensation reaction can as an ethylene glycol solution, and the concentration of the solution is not particularly limited, but it is preferably a concentration that completely dissolves.

≪ (b) 0.5 × M1 ≦ P ≦ 1.5 × M1≫
The phosphorus atom content (P) in the polyester resin composition of the present invention needs to be 0.5 to 1.5 times M1. By setting P to 0.5 times or more of M1, sufficient particles can be obtained to improve the stability of the polyester fiber spinning process, and dullness due to precipitation of metal antimony can be suppressed. Can keep.
By setting P to 1.5 times or less of M1, by-product of diethylene glycol that reduces the thermal stability of the fiber is suppressed, which is preferable.

≪Germanium oxide≫
The polyester resin composition of the present invention contains germanium oxide.

  Examples of germanium oxide include germanium dioxide, germanium hydroxide, germanium tetrachloride, and the like, but germanium dioxide is preferred in view of safety.

  The germanium oxide is preferably added to the polycondensation reaction can as an ethylene glycol solution, and the concentration of the solution is not particularly limited, but it is preferably a concentration that completely dissolves.

  The germanium oxide suppresses the generation of extremely large particles and provides a uniform dispersibility of fine particles, thereby suppressing the occurrence of fluff during the production of polyester fibers and reducing the yarn unevenness. Further, dullness due to precipitation of metal antimony is suppressed, and a resin composition having a good color tone can be obtained. As a result, the resulting polyester fiber is also less dull and has a high gloss and good color tone. When the addition amount of germanium oxide is increased, the maximum fluctuation range of the number of particles is reduced. Here, the maximum fluctuation range is obtained as follows.

≪Maximum fluctuation range measurement method≫
6 mg of the obtained polyester fiber was sandwiched between two cover glasses heated to 270 ° C., rapidly cooled after melt pressing, and used as a thin film sample. This is subjected to TEM observation using a transmission electron microscope (H-7600, manufactured by Hitachi, Ltd.). Using Nippon Roper Co., Ltd. Image-ProPLUS as analysis software, particle measurement of the image observed by TEM is performed 5 times, and the number of particles is counted. The average value of the number of particles was 100%, and the number of particles obtained by each particle measurement was expressed in%. The largest deviation from the average value was taken as the maximum fluctuation range.

The fluctuation range of the polyester resin composition of the present invention is within ± 15%, more preferably within ± 10%. When the fluctuation range is within ± 15%, the dispersibility of the particles is good, and the multifilament yarn-making property is also good.
Germanium oxide is also added to the polycondensation reaction can in the step of adding the ii polycondensation catalyst as an ethylene glycol solution.

<< (c) 20≤G≤150 >>
The addition amount (G) of the germanium oxide in the present invention is required to be 20 ppm or more and 150 ppm or less, more preferably 30 ppm or more and 120 ppm or less as the amount of germanium atoms with respect to the polyester resin composition. . When the addition amount is 20 ppm or more, the dispersibility of the internal particles is maintained, and the multifilament yarn forming property having a single fiber fineness of 0.6 dtex or more and 3 dtex or less is secured. For example, the yarn forming property is maintained even when the single fiber fineness is within the above range and the total fineness is 84 dtex or less. In addition, the maximum fluctuation range of the number of particles becomes smaller as the addition amount increases, but if the addition amount exceeds 120 ppm, the effect on dispersibility will reach its peak, so germanium metal is a rare metal and lacks resource, and is expensive. Therefore, if it is made 150 ppm or less, an increase in cost due to addition can be avoided.

≪Alkali metal salt of carboxylic acid≫
In the polyester resin composition of the present invention, an alkali metal salt of a carboxylic acid is used in place of a part of the alkaline earth metal salt of the carboxylic acid, and an average particle size of 0.01 to 3 μm formed from the phosphoric acid ester is used. It is preferable to further disperse the particles. The alkali metal salt of carboxylic acid suppresses by-production of diethylene glycol during polycondensation of the polyester resin in addition to particle formation.

Examples of the alkali metal salt of carboxylic acid include lithium acetate, sodium acetate, potassium acetate, lithium benzoate, sodium benzoate, and potassium benzoate. Of these, acetates, particularly sodium acetate, are preferable because they are easy to handle and have the effect of suppressing by-production of diethylene glycol.
The alkali metal salt of the carboxylic acid is preferably added to the polycondensation reaction can as an ethylene glycol solution, and the concentration of the solution is not particularly limited, but is preferably a concentration that completely dissolves.

≪Alkali metal hydroxide≫
In the polyester resin composition of the present invention, an alkali metal hydroxide is used in place of a part of the alkaline earth metal salt of the carboxylic acid, and an average particle diameter of 0.01 to 3 μm formed from the phosphate and the phosphate ester. The particles may be further dispersed. Alkali metal hydroxides also suppress by-production of diethylene glycol during polycondensation of the polyester resin in addition to particle formation.

Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Among them, sodium hydroxide is preferable because it is easy to handle and has an effect of suppressing by-production of diethylene glycol.
The alkali metal hydroxide is preferably added to the polycondensation reaction can as an ethylene glycol solution, and the concentration of the solution is not particularly limited, but is preferably a concentration that allows complete dissolution.

≪Alkali metal atom content (M2) ≫
In the present invention, the content (M2) of the alkali metal atom in the finished polyester resin composition satisfies the following two formulas simultaneously in both the case of the alkali metal salt of the carboxylic acid and the case of the alkali metal hydroxide. preferable.
(A ′) 100 ≦ M1 + M2 ≦ 500
(B ′) 0.5 × (M1 + M2) ≦ P ≦ 1.5 × (M1 + M2)
Here, M1 and P represent the content (ppm) of alkaline earth metal atoms and the content (ppm) of phosphorus atoms, respectively, with respect to the finished polyester resin composition.

  By setting M1 + M2 to 100 ppm or more, sufficient particles can be obtained to improve the stability of the polyester fiber spinning process. Since the generation of coarse particles can be suppressed by suppressing to 500 ppm or less, clogging of the filter for filtering the melted polyester resin composition during spinning does not occur, and the stability of the polyester fiber yarn production process is kept good. be able to.

  At the same time, M1 + M2 preferably satisfies the following conditions. That is, it is preferable that P is 0.5 to 1.5 times M1 + M2. By setting P to 0.5 times or more of M1 + M2, it is possible to obtain sufficient particles to improve the stability of the polyester fiber spinning process, and to suppress dullness due to precipitation of metal antimony. Can keep. By setting P to 1.5 times or less of M1 + M2, it is preferable to suppress the by-production of diethylene glycol that lowers the thermal stability of the fiber.

≪Polyester fiber≫
The preferable single fiber fineness of the polyester fiber comprising the polyester resin composition of the present invention is 0.3 dtex or more and 3.0 dtex or less, more preferably 0.6 dtex or more and 2.0 dtex or less. Since the polyester resin composition of the present invention has good particle dispersibility, when the single fiber fineness is small as described above, the slipperiness and runnability are improved, and the generation of fluff during stretching is suppressed. be able to. In particular, when the total fineness is 84 dtex or less, the effect on the improvement of the yarn forming property and the passability of the post-processing step is remarkable. The above-mentioned effect is remarkable when the cation dyeability is imparted to the polyester fiber made of the polyester resin composition of the present invention and the polyester fiber has a relatively low strength.
Further, the cross-sectional shape of the polyester fiber is not particularly limited, but the formation of particles is effective in suppressing the generation of fluff in the irregular cross-section.

  A known melt spinning production method can be employed for the polyester fiber comprising the modified polyester resin composition of the present invention. First, in the melt spinning process, the multifilament yarn discharged from the discharge hole from the spinneret is wound as a non-stretched yarn by a known method and then stretched without being wound once after being discharged. It is good also as a drawn yarn.

≪Spinning method≫
In the present invention, the spinning temperature is 270 to 300 ° C., the spinning speed is 1000 to 2000 m / min, the stretching temperature is 70 to 90 ° C., the heat setting temperature is 120 to 160 ° C., the stretching speed is 400 to 1000 m / min, and the draw ratio is the maximum of the undrawn yarn. A stretch ratio of about 0.65 to 0.85 is preferable. The maximum draw ratio refers to the ratio at which the undrawn yarn is drawn until it is cut under the conditions of a drawing temperature of 80 ° C., a heat setting temperature of 145 ° C., and a drawing speed of 600 m / min.
The spinning and drawing conditions are not limited to the above specific examples. The high-speed spinning of 2000 m / min or more, the POY method of winding as a semi-undrawn yarn, or the high-speed spinning of 2000 m / min or more, Further, it may be obtained by a spin draw method or the like that is continuously stretched without winding.

  Furthermore, as long as the effects of the present invention are not impaired, a composite fiber with another fiber may be used.

  The form of the polyester fiber of the present invention may be either a long fiber or a short fiber, and is used after being subjected to post-processing such as crimping, false twisting, or treatment with a chemical solution as necessary.

≪Use of polyester fiber of the present invention≫
The polyester fiber of the present invention may be used alone or other fibers may be used in textile products such as swimwear, sports inners, lingerie, foundations and embroidery laces, which are uses of the polyester fiber of the present invention. . By combining with other fibers, for example, a texture such as gloss, coolness, sharpness, and wetness can be imparted to the textile.

  In addition, as other fibers to be combined, for example, natural fibers such as cotton, hemp and silk, regenerated fibers such as rayon, semi-synthetic fibers such as acetate, or thermoplastic fibers such as polyester fibers can be used. In addition, the cross-sectional shape of the single fiber constituting each fiber is not particularly limited, and in consideration of the texture and gloss of the resulting fiber product, the cross-section of the yarn such as chrysanthemum, circular, flat, Y-shaped, etc. What is necessary is just to select a shape suitably. Further, the single fiber fineness and dyeing characteristics of the other fibers are not particularly limited. Furthermore, the polyester fiber of the present invention may be twisted, and the twist direction and the number of twists of the twisted yarn in this case are not particularly limited, and the number of constituent yarns, the number of twists, etc. are the texture of the target textile product. Or as long as the appearance can be obtained.

Next, the present invention will be specifically described by way of examples, but is not limited thereto.
The measurement and evaluation methods for various characteristic values in the examples are as follows.

(1) Intrinsic viscosity ([η])
Solvent: Equal mass mixture of phenol and ethane tetrachloride Temperature: 20 ° C
Procedure: A solvent at 20 ° C. is added to a sample of the polyester resin composition so as to be a 0.5 mass% solution, and dissolved by heating. After cooling to room temperature, the relative viscosity ηr is measured using a fully automatic viscometer (AVS-6 manufactured by Sun Electronics). The intrinsic viscosity [η] was calculated from the measured relative viscosity.

(2) Diethylene glycol content (D%)
The obtained polyester resin composition was hydrolyzed with alkali. Using a gas chromatograph GC-9A (manufactured by Shimadzu Corporation), a predetermined amount of the hydrolyzate was quantified in terms of the number of moles of ethylene glycol (hereinafter abbreviated as EG) and diethylene glycol (hereinafter abbreviated as DEG). The ratio (%) of the number of moles of DEG relative to the sum of the number of moles of EG and DEG.

(3) Particle size 6 mg of polyester fiber was sandwiched between two cover glasses heated to 270 ° C., rapidly cooled after melt pressing, and used as a thin film sample. This was subjected to TEM observation and EDS analysis using a transmission electron microscope H-7600 (manufactured by Hitachi, Ltd.). The average particle diameter of the particles in the TEM observation image was measured. The average particle size was divided into the following 4 ranks. In addition, Nippon Roper Co., Ltd. Image-ProPLUS was used for the measurement of an average particle diameter as analysis software.

In Table 1, the following notation was used.
A: Average particle diameter of 0.01 μm or more and less than 3.0 μm B: Average particle diameter of 3.0 μm or more and less than 5.0 μm C: Average particle diameter of less than 0.01 μm D: Average particle diameter of 5.0 μm or more E: Internal particles confirmed Can not.

(4) Fluctuation width of particles 6 mg of the obtained polyester fiber is sandwiched between two cover glasses heated to 270 ° C., rapidly cooled after melt pressing, and used as a thin film sample. This is subjected to TEM observation using a transmission electron microscope (H-7600, manufactured by Hitachi, Ltd.). Using Nippon Roper Co., Ltd. Image-ProPLUS as analysis software, particle measurement of the image observed by TEM is performed 5 times, and the number of particles is counted. The average value of the number of particles was 100%, and the number of particles obtained by each particle measurement was expressed in%. The largest deviation from the average value was taken as the maximum fluctuation range. Table 1 shows the maximum fluctuation range.

(5) Measurement of the number of fluff The number of fluff was measured using the drawn yarn and the warping machine. The measurement length was 3 × 10 ⁸ m, and the number of fluff (number / 10 ⁸ m) is shown in Table 1. Two pieces / 10 ⁸ m or less were accepted.

(6) Strength and elongation Based on JIS L 1013, it measured using Tensilon UTM-4-100 type (made by Orientec).

(7) Dye exhaustion rate The obtained polyester fiber was used as a tubular knitted fabric and dyed under the following dyeing stock solution and dyeing conditions. The absorbance U of the dyed residual solution after dyeing was measured at a wavelength λ = 590 μm using a spectrophotometer BPS-3T type (manufactured by Hitachi, Ltd.). From the U and the absorbance U0 of the dye stock solution, the exhaustion rate was determined by the following equation. Table 1 shows the exhaustion rate.

Exhaust rate (%) = [(U0−U) / U0] × 100
Stock solution: Astrazon Blue FRR (cationic dye manufactured by Bayer) 1.5% o.d. w. f,
Auxiliary agent: 0.6 ml / l acetic acid, 0.6 g / l sodium acetate
Dyeing conditions: Bath ratio: 1/100 In a normal pressure boiling state, a 30 minute exhaustion rate of 90% or more was considered acceptable.

Example 1
(1) A slurry having a molar ratio of terephthalic acid (hereinafter abbreviated as TPA) and EG of 1 / 1.6 was continuously supplied to an esterification reaction can in which a polyester gomer was present. The esterification reaction was carried out so that the inside of the esterification reaction can was maintained at a temperature of 250 ° C. and a pressure of 0.1 MPa, and the residence time was 8 hours. As a result, a polyester oligomer having a reaction rate of 95% was continuously obtained. 46.5 kg of the obtained polyester oligomer was transferred to a polycondensation reaction can.

(2) 7.3 kg of an EG dispersion in which the concentration of adipic acid (hereinafter abbreviated as AD), which is an aliphatic dicarboxylic acid having 2 to 8 carbon atoms, was adjusted to 25% by weight, Magnesium acetate which is an alkaline earth metal salt of acid and lithium acetate which is an alkali metal salt of carboxylic acid were added.
At this time, M1 (magnesium atom) = 120 ppm and M2 (lithium atom) = 55 ppm.

(3) The temperature in the polycondensation reaction vessel was set to 235 ° C., and the mixture was stirred for 5 minutes.
(4) Further, in the polycondensation reaction vessel, triethyl phosphate as a phosphate ester, germanium dioxide as a germanium oxide, and 5-sodium sulfoisophthalic acid (hereinafter abbreviated as SIP) as a sulfoisophthalic acid. 5.6 kg of EG solution adjusted to a concentration of 35% by weight was added.
At this time, P = 140 ppm and G = 30 ppm.

(5) The temperature in the polycondensation reaction vessel was set to 235 ° C., and the mixture was stirred and mixed for 60 minutes.
(6) Further, 340 ppm of antimony trioxide as a polycondensation catalyst was added to the polycondensation reaction can as a compound with respect to the finished polyester resin composition.

(7) While raising the temperature in the polycondensation reaction can to 280 ° C., the pressure was gradually reduced to 1.2 hPa or less after 60 minutes. While stirring under these conditions, a polycondensation reaction was carried out until a predetermined stirring stop torque was reached, and the chips were dispensed by a conventional method. The polyester resin in the obtained polyester resin composition has a copolymerization ratio S (mol%) of sulfoisophthalic acid units = 2 and a copolymerization ratio A (mol%) of aliphatic dicarboxylic acid having 2 to 8 carbon atoms = 5. there were. Furthermore, the color tone was good, and the intrinsic viscosity [η] = 0.56 and D% = 4.3 mol%. The average particle size of the particles was A rank, and the maximum fluctuation range was ± 5%.

(8) Subsequently, the obtained polyester resin composition chip was dried by a conventional method, using a spinning device provided with a spinneret having a triangular section of 36 holes, at a spinning temperature of 290 ° C. and a spinning speed of 1600 m / min. The undrawn yarn obtained after spinning was drawn at a drawing speed of 600 m / min, a drawing temperature of 78 ° C., a heat setting temperature of 150 ° C., and a maximum drawing ratio of 0.72 times, and 56 dtex / 36 filament (hereinafter abbreviated as f). ) Stretched polyester fiber was obtained. The evaluation results of the polyester fiber are shown in Table 1.

(Example 2)
The amount of AD EG dispersion was changed to 14 kg (A = 10 mol%), the amount of SIP EG ester EG solution added was changed to 7.5 kg (S = 3 mol%), and the amount of germanium dioxide added ( A polyester resin composition and polyester fiber were obtained in the same manner as in Example 1 except that G) was changed to 60 ppm. The evaluation results are shown in Table 1.

  Moreover, a woven fabric (warp density of 10.56 / cm, weft density of 135 / 2.54 cm, satin structure) was woven using the obtained polyester fiber. After scouring by a conventional method, dyeing was performed with a cationic dye [Astrazon Blue FRR (cationic dye manufactured by Bayer)] at a dyeing temperature of 100 ° C. and a dyeing time of 30 minutes. When the texture of the obtained woven fabric was evaluated, an excellent color tone was obtained, the sharpness peculiar to the cationic dye was excellent, and a moderate swell and softness were obtained.

(Example 3)
A polyester resin composition was obtained in the same manner as in Example 1 except that the addition amounts of magnesium acetate, lithium acetate and triethyl phosphate were changed to M1 = 150 ppm, M2 = 60 ppm, and P = 230 ppm. The evaluation results are shown in Table 1.
When spinning the obtained polyester resin composition, a polyester fiber (33 dtex / 12f) was produced in the same manner as in Example 1 except that a spinneret having a 12-hole circular cross section was used and the spinning speed was 1400 m / min. Got. The evaluation results are shown in Table 1.

Example 4
Except for changing the addition amount of magnesium acetate, lithium acetate and triethyl phosphate to M1 = 200 ppm, M2 = 80 ppm, P = 390 ppm, and changing the addition amount (G) of germanium dioxide to 90 ppm, It carried out like Example 1 and obtained the polyester resin composition. The evaluation results are shown in Table 1.
When spinning the obtained polyester resin composition, a polyester fiber (66 dtex / 96f) was produced in the same manner as in Example 1 except that a spinneret having a 96-hole circular cross section was used and the spinning speed was 1400 m / min. Got. The evaluation results are shown in Table 1.

(Example 5)
A polyester resin composition was obtained in the same manner as in Example 1 except that the addition amount (G) of germanium dioxide was changed to 150 ppm. The evaluation results are shown in Table 1.
When spinning the obtained polyester resin composition, a polyester fiber (56 dtex / 48f) was produced in the same manner as in Example 1 except that a spinneret having a 48-hole circular cross section was used and the spinning speed was 1400 m / min. Got. The evaluation results are shown in Table 1.

(Example 6)
Except having changed the addition amount (G) of germanium dioxide so that it might become 20 ppm, it carried out similarly to Example 1 and the polyester resin composition and the polyester fiber were obtained. The evaluation results are shown in Table 1.

(Example 7)
(1) Same as Example 1.
(2) Magnesium acetate, which is an alkaline earth metal salt of carboxylic acid, and lithium acetate, which is an alkali metal salt of carboxylic acid, were added to the polycondensation reaction vessel.
At this time, M1 (magnesium atom) = 120 ppm and M2 (lithium atom) = 55 ppm.

(3) Same as Example 1.
(4) Further, triethyl phosphate as a phosphate ester and germanium dioxide as a germanium oxide were added to a polycondensation reaction can.
At this time, P = 140 ppm and G = 60 ppm.

(5) Same as Example 1.
(6) Same as Example 1.
(7) While raising the temperature in the polycondensation reaction can to 280 ° C., the pressure was gradually reduced to 1.2 hPa or less after 60 minutes. While stirring under these conditions, a polycondensation reaction was carried out until a predetermined stirring stop torque was reached, and the chips were dispensed by a conventional method. The polyester resin in the obtained polyester resin composition has a copolymerization rate S (mol%) of sulfoisophthalic acid units = 0 and a copolymerization rate A (mol%) of aliphatic dicarboxylic acids having 2 to 8 carbon atoms = 0. there were. Furthermore, the color tone was good, and the intrinsic viscosity [η] = 0.73 and D% = 2.1 mol%. The average particle size of the particles was A rank, and the maximum fluctuation range was ± 3%.

(8) Subsequently, the obtained polyester resin composition chip was dried by a conventional method, using a spinning device provided with a spinneret having a 96-hole circular cross section, at a spinning temperature of 295 ° C. and a spinning speed of 1400 m / min. The undrawn yarn obtained by spinning was drawn at a drawing speed of 600 m / min, a drawing temperature of 83 ° C., a heat setting temperature of 145 ° C., and a maximum drawing ratio of 0.72 times to obtain a drawn polyester fiber of 56 dtex / 96 f. . The evaluation results of the polyester fiber are shown in Table 1.

(Example 8)
Except having changed the predetermined stirring stop torque, it carried out similarly to Example 7, and obtained the polyester resin composition (Intrinsic viscosity [(eta)] = 0.67, D%: 2.3 mol%) and the polyester fiber. . The evaluation results are shown in Table 1.

Example 9
Except having changed the predetermined stirring stop torque, it carried out similarly to Example 7 and obtained the polyester resin composition (Intrinsic viscosity [(eta)] = 0.62, D%: 2.3 mol%). The evaluation results are shown in Table 1.
When the obtained polyester resin composition was spun, it was carried out in the same manner as in Example 7 except that the discharge amount of the polyester resin composition was changed to obtain a polyester fiber (40 dtex / 96f). The evaluation results are shown in Table 1.

(Example 10)
Except having changed the addition amount (G) of germanium dioxide so that it might be set to 30 ppm, it carried out similarly to Example 9 and obtained the polyester resin composition and the polyester fiber. The evaluation results are shown in Table 1.

(Example 11)
A polyester resin composition and polyester fibers were obtained in the same manner as in Example 1 except that the amount of SIP EG ester added to the EG solution was changed to 1.2 kg (S = 0.5 mol%). The evaluation results are shown in Table 1.
A woven fabric was prepared from the obtained polyester fiber by the weaving method described in Example 2. When the texture of the obtained woven fabric was evaluated, since the copolymerization amount of SIP was small, the other characteristics were good although the sharpness specific to the cationic dye was poor.

(Example 12)
Example 1 except that the addition amount of the EG solution of SIP EG ester was changed to 1.2 kg (S = 0.5 mol%) and the addition amount (G) of germanium dioxide was changed to 150 ppm. In the same manner as above, a polyester resin composition was obtained. The evaluation results are shown in Table 1.

  When the obtained polyester resin composition was spun, a polyester fiber (66 dtex / 136f) was produced in the same manner as in Example 1 except that a spinneret with a 136-hole circular cross section was used and the spinning speed was 1200 m / min. Got. The evaluation results are shown in Table 1.

(Comparative Example 1)
The main repeating unit is not composed of polyethylene terephthalate (A + S> 15 mol%).
The addition amount of AD EG dispersion was changed to 24 kg (A = 17 mol%), the addition amount of EG solution of SIP EG ester was changed to 5.6 kg (S = 2 mol%), and the addition amount of germanium dioxide ( A polyester resin composition and polyester fiber were obtained in the same manner as in Example 1 except that G) was changed to 60 ppm. The evaluation results are shown in Table 1.

(Comparative Example 2)
A polyester resin composition was obtained in the same manner as in Example 1 except that the addition amounts of magnesium acetate, lithium acetate and triethyl phosphate were changed to M1 = 50 ppm, M2 = 30 ppm, and P = 100 ppm. The evaluation results are shown in Table 1.
When spinning the obtained polyester resin composition, a polyester fiber (33 dtex / 8f) was prepared in the same manner as in Example 1 except that a spinneret with an 8-hole circular cross section was used and the spinning speed was 1600 m / min. Got. The evaluation results are shown in Table 1.

(Comparative Example 3)
A polyester resin composition and a polyester fiber are obtained in the same manner as in Example 1 except that the addition amounts of magnesium acetate, lithium acetate and triethyl phosphate are changed so that M1 = 120 ppm, M2 = 55 ppm, and P = 300 ppm. It was. The evaluation results are shown in Table 1.

(Comparative Example 4)
The same procedure as in Example 1 was carried out except that magnesium acetate and triethyl phosphate were not added. A polyester resin composition and polyester fiber were obtained. The evaluation results are shown in Table 1.

(Comparative Example 5)
A polyester resin composition and polyester fibers were obtained in the same manner as in Example 1 except that the amount of germanium dioxide added (G) was changed to 17 ppm. The evaluation results are shown in Table 1.

(Comparative Example 6)
Except having changed the addition amount (G) of germanium dioxide into 0 ppm, it carried out similarly to Example 1 and obtained the polyester resin composition and the polyester fiber. The evaluation results are shown in Table 1.

(Comparative Example 7)
Except having changed the addition amount (G) of germanium dioxide into 0 ppm, it carried out similarly to Example 7 and obtained the polyester resin composition and the polyester fiber. The evaluation results are shown in Table 1.

≪Summary≫
The germanium oxide suppresses the generation of extremely large particles and provides a uniform dispersibility of fine particles, thereby suppressing the occurrence of fluff during the production of polyester fibers and reducing the yarn unevenness. Further, dullness due to precipitation of metal antimony is suppressed, and a resin composition having a good color tone can be obtained. As a result, the resulting polyester fiber is also less dull and has a high gloss and good color tone. When the addition amount of the germanium compound is increased, the maximum fluctuation range of the particles is decreased.

  As is clear from Table 1, the polyester resin composition of the present invention suppresses the generation of extremely large particles, provides a uniform dispersibility of fine particles, and generates a sufficient amount of particles. Moreover, it has an intrinsic viscosity suitable for yarn production. The polyester fiber composed of the polyester resin composition of the present invention has sufficient strength and elongation. Particularly, the polyester fiber composed of the polyester resin composition obtained by copolymerizing AD and SIP is dyed by normal pressure dyeing with a cationic dye. The dyeability is good.

  In Comparative Example 1, since the main repeating unit is not composed of polyethylene terephthalate (A + S> 15 mol%), the resulting polyester fiber has low strength and is not practical. In Comparative Example 2, since the addition amount of lithium acetate and magnesium acetate was small, a sufficient amount of particles was not generated, so that there were many fluffs and the stability of the spinning process was lowered. In Comparative Example 3, since P in the polymer was 1.7 times M1 + M2, D% was high, and many coarse particles were generated, so that there were many fluffs and the stability of the spinning process was lowered. In Comparative Example 4, since P = 0 ppm, particles were not formed, and as a result, there were many fluffs and the stability of the spinning process was lowered. In Comparative Example 5, since G <20 ppm, the dispersibility of the formed particles was poor, and as a result, there were many fluffs and the stability of the yarn production process was low. In Comparative Examples 6 and 7, since G = 0 ppm, the dispersibility of the particles was poor, and extremely large particles were formed. As a result, the generation of fluff was extremely large and the stability of the spinning process was extremely low.

Claims (15)

An average particle size of 0.01% formed from an alkaline earth metal salt of a carboxylic acid and a phosphate ester so that the main repeating unit of the polyester resin composed of ethylene terephthalate satisfies the following formulas (a) to (c): A polyester resin composition comprising particles having a particle size of 3 μm and germanium oxide.
(A) 100 ≦ M1 ≦ 500
(B) 0.5 × M1 ≦ P ≦ 1.5 × M1
(C) 20 ≦ G ≦ 150
However, M1, P, and G represent the content (ppm) of alkaline earth metal atoms, the content (ppm) of phosphorus atoms, and the content (ppm) of germanium atoms, respectively, with respect to the finished polyester resin composition. In order to satisfy the following formulas (a ′), (b ′) and (c), an average particle diameter of 0.01 to 0.01 formed from an alkali metal salt of a carboxylic acid or an alkali metal hydroxide and a phosphate ester The polyester resin composition according to claim 1, comprising 3 μm particles.
(A ′) 100 ≦ M1 + M2 ≦ 500
(B ′) 0.5 × (M1 + M2) ≦ P ≦ 1.5 × (M1 + M2)
(C) 20 ≦ G ≦ 150
However, M2 shows content (ppm) of an alkali metal atom with respect to the completed polyester resin composition.   The polyester resin composition according to claim 1, wherein an alkaline earth metal salt of acetic acid is used as the alkaline earth metal salt of carboxylic acid.   The polyester resin composition according to claim 2, wherein an alkali metal salt of acetic acid is used as the alkali metal salt of carboxylic acid. A polyester resin obtained by copolymerizing an alkali metal salt unit of sulfoisophthalic acid and an aliphatic dicarboxylic acid unit having 2 to 8 carbon atoms so as to satisfy the following formulas (d) and (e) is used as the polyester resin. The polyester resin composition according to 1 or 3.
(D) 0.8 ≦ S ≦ 5
(E) 2 ≦ A ≦ 15
However, S and A show the copolymerization rate (mol%) of the sulfoisophthalic acid unit in a polyester resin, and the copolymerization rate (mol%) of a C2-C8 aliphatic dicarboxylic acid, respectively. A polyester resin obtained by copolymerizing an alkali metal salt unit of sulfoisophthalic acid and an aliphatic dicarboxylic acid unit having 2 to 8 carbon atoms so as to satisfy the following formulas (d) and (e) is used as the polyester resin. The polyester resin composition according to 2 or 4.
(D) 0.8 ≦ S ≦ 5
(E) 2 ≦ A ≦ 15
However, S and A show the copolymerization rate (mol%) of the sulfoisophthalic acid unit in a polyester resin, and the copolymerization rate (mol%) of a C2-C8 aliphatic dicarboxylic acid, respectively. In order to satisfy the following formulas (a) to (c), the content of the alkaline earth metal atom, phosphorus atom and germanium atom in the polyester oligomer of terephthalic acid and ethylene glycol satisfies the following formulas (a) to (c): A method for producing a polyester resin composition comprising adding an alkaline earth metal salt, a phosphate ester and germanium oxide as additives and performing polycondensation.
(A) 100 ≦ M1 ≦ 500
(B) 0.5 × M1 ≦ P ≦ 1.5 × M1
(C) 20 ≦ G ≦ 150
However, M1, P, and G show the content (ppm) of alkaline earth metal atoms, the content (ppm) of phosphorus atoms, and the content (ppm) of germanium atoms, respectively, with respect to the finished polyester resin composition. In order to satisfy the following formulas (a ′), (b ′) and (c), the content of the alkaline earth metal atom, phosphorus atom and germanium atom in the finished polyester resin composition may be further increased as a carboxylic acid. The manufacturing method of the polyester resin composition of Claim 7 which adds the alkali metal salt or alkali metal hydroxide of this.
(A ′) 100 ≦ M1 + M2 ≦ 500
(B ′) 0.5 × (M1 + M2) ≦ P ≦ 1.5 × (M1 + M2)
(C) 20 ≦ G ≦ 150
However, M2 shows content (ppm) of an alkali metal atom with respect to the completed polyester resin composition.   The method for producing a polyester resin composition according to claim 7, wherein an alkaline earth metal salt of acetic acid is used as the alkaline earth metal salt of carboxylic acid.   The method for producing a polyester resin composition according to claim 8, wherein an alkali metal salt of acetic acid is used as the alkali metal salt of carboxylic acid. The polyester according to claim 7 or 9, wherein an alkali metal salt of ethylene glycol ester of sulfoisophthalic acid and an aliphatic dicarboxylic acid having 2 to 8 carbon atoms are added as monomers so as to satisfy the following formulas (d) and (e): A method for producing a resin composition.
(D) 0.8 ≦ S ≦ 5
(E) 2 ≦ A ≦ 15
However, S and A show the copolymerization rate (mol%) of the sulfoisophthalic acid unit in a polyester resin, and the copolymerization rate (mol%) of a C2-C8 aliphatic dicarboxylic acid, respectively. The polyester resin according to claim 8 or 10, wherein an alkali metal salt of sulfoisophthalic acid ethylene glycol ester and an aliphatic dicarboxylic acid having 2 to 8 carbon atoms are added as monomers so as to satisfy the following formulas (d) and (e): A method for producing the composition.
(D) 0.8 ≦ S ≦ 5
(E) 2 ≦ A ≦ 15
However, S and A show the copolymerization rate (mol%) of the sulfoisophthalic acid unit in a polyester resin, and the copolymerization rate (mol%) of a C2-C8 aliphatic dicarboxylic acid, respectively.   The method for producing a polyester resin composition according to any one of claims 7 to 12, wherein an additive and a monomer to be added are previously dissolved or dispersed in ethylene glycol and added to a polyester oligomer of terephthalic acid and ethylene glycol.   A polyester fiber comprising the polyester resin composition according to claim 1 and having a single fiber fineness of 0.6 to 3 dtex.   The textile product which uses the polyester fiber of Claim 14 for at least one part.