JP2004339685A - Copolymerized poly(trimethylene terephthalate) fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide poly(trimethylene terephthalate) (PTT) fiber having high toughness, causing little shrinkage in dyeing or heat-setting and having excellent processing properties, and to provide a method for producing the fiber. <P>SOLUTION: The copolymerized poly(trimethylene terephthalate) fiber satisfies the following conditions (1) to (6): (1) ester-forming sulfonate of 0.5-5 mol% is copolymerized based on a total dicarbonic acid component, (2) bis(3-hydroxypropyl) ether of 0.1-2.5 wt.% is copolymerized, (3) intrinsic viscosity is 0.65-1.5 dl/g, (4) amount of terminal carboxy groups is ≤25 milli-equivalent/kg-fiber, (5) toughness is ≥16, wherein the toughness is calculated by the following equation: Toughness=[Strength (cN/dtex)]×[Elongation (%)]<SP>1/2</SP>and (6) U% is 0-3%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to copolymerized polytrimethylene terephthalate (hereinafter, polytrimethylene terephthalate is abbreviated as PTT), a method for producing the same, fibers and a fiber product using the same. Specifically, the present invention relates to a copolymerized PTT having a high molecular weight, which is a raw material of a PTT fiber dyeable with a cationic dye, a method for producing the same, and a fiber and a fiber product using the same.
More specifically, a high-molecular-weight copolymerized PTT having excellent hue, which can be produced at a high solid-state polymerization rate, has a low rate of decrease in viscosity upon melting, and is a raw material for cationic dye-dyeable PTT fibers, and The present invention relates to a cationic dye-dyeable PTT fiber which has high processability, does not significantly shrink during dyeing or heat setting, and has excellent processing properties, and the fiber product.

PTT fiber obtained by melt spinning from a polycondensate of terephthalic acid or a lower alcohol ester of terephthalic acid and 1,3-propanediol (also referred to as trimethylene glycol) has a surprisingly soft texture and drapability that have never been achieved before. It has many features that cannot be obtained with existing synthetic fibers such as polyethylene terephthalate fiber (hereinafter, polyethylene terephthalate is abbreviated as PET) and nylon 6 fiber, such as excellent stretchability, low-temperature dyeability, and weather resistance. .
The Applicant has recently launched the world's first PTT fiber (registered trademark "Solo" fiber), overcoming many difficulties associated with the development of PTT, PTT fiber, and its processing, products, and the like.
The use of PTT fiber can be further expanded by combining it with other material fibers or by performing post-processing. However, in the case of the conventional PTT fiber, there may be a problem with dyeing depending on the type of the fiber to be combined and the type of processing technique. For example, since PTT fiber can be substantially dyed only with a disperse dye, when the PTT fiber is combined with a polyurethane elastic yarn, or when a PTT fiber fabric is processed with a polyurethane resin, the disperse dye has a structure. There is a problem in that the dye is transferred to coarse urethane elastic yarn or resin, and dyeing fastness such as washing fastness, sweat fastness and dry cleaning fastness is reduced.
On the other hand, when the PTT fiber is dyed with a cationic dye, the cationic dye is ionically bonded to a sulfonate, which is a dyeing seat introduced into the PTT fiber, so that the dye is transferred. No problems occur and high color fastness is achieved. In addition, a characteristic that the sharpness of the fabric after dyeing is increased is also exhibited.

The present inventors have solved the above-mentioned problems relating to dyeing, and as a means for further utilizing the excellent characteristics of PTT fiber, PTT fiber having cationic dye dyeability (hereinafter abbreviated as CD-PTT fiber). Has already been proposed (Patent Document 1). This technology involves an esterification reaction of terephthalic acid or a lower alcohol ester of terephthalic acid typified by dimethyl terephthalate with a diol component of 1,3-propanediol, followed by a polycondensation reaction. By adding an ester-forming sulfonic acid metal salt serving as a dyeing seat of a cationic dye at an arbitrary stage during the dyeing, a PTT having a cationic dye-dyeing property (hereinafter referred to as CD- PTT) and its fibers. Although this technique is excellent in that it provides a PTT having cationic dye dyeability, which has been difficult in the past, it still has an insufficient point in terms of industrial productivity. Further, although the CD-PTT obtained by the above technique is excellent in whiteness, it is not always satisfactory in fiber applications that require a higher level of whiteness and strength.
On the other hand, Patent Literature 2 discloses an esterification reaction of 1,3-propanediol and a terephthalic acid component with respect to not a CD-PTT but a homopolymer of PTT (hereinafter referred to as homoPTT). After obtaining a prepolymer having an intrinsic viscosity of 0.7 to 0.8 by subjecting the product to polycondensation, the obtained prepolymer is subjected to solid-phase polycondensation at a temperature of 190 to 210 ° C. to obtain an intrinsic viscosity of 0.9 or more. Thus, a method of obtaining a PTT having a b value of 10 or less and an oligomer content of 1 wt% or less is disclosed. Patent Literature 3 discloses a homo-PTT polymerization technique that combines a titanium catalyst and a magnesium catalyst and has excellent solid-state polymerization speed and melt stability.

However, neither of these publications describes or suggests the significance of copolymerizing CD-PTT or an ester-forming metal salt of sulfonic acid. In particular, as described later, when an ester-forming sulfonic acid metal salt is used as a copolymerization component, the melt stability is worse than that of homo-PTT. Therefore, the technology used for homo-PTT is directly applied to CD-PTT. Although the same effect cannot be expected even if it is applied, the above publication does not describe or suggest any solution. Further, the homo-PTT described in any of the publications is not sufficient in terms of whiteness, and particularly in Patent Document 3, since a magnesium catalyst is used in combination at the time of polymerization, the L value (brightness) of the polymer is 70. , And only a darkened polymer can be obtained, and it cannot be applied to CD-PTT fiber which requires sharp color development.
As for the known CD-PTT fiber, there is a point to be improved similarly to the CD-PTT polymer. That is, the conventional CD-PTT fiber is 1) low in toughness because it is made of a polymer having a low molecular weight (toughness indicates the toughness of the fiber, and is usually 1/2 power of fiber strength and elongation). The problem is that the material is easily broken when it is made into a fabric, and 2) Since it is excessively stretched despite its low molecular weight, it is amorphous due to heat during processing such as dyeing and heat setting. There is a problem that since the molecules of the portion cause the orientation to relax and largely shrink, it becomes stiff and it is difficult to sufficiently develop a soft texture.

WO 99/09238 pamphlet JP-A-08-31177 JP 2000-159876 A

The present inventors have found the following problems at the stage where the research on the polymerization technology and the spinning technology of CD-PTT is energetically advanced.
In the melt polymerization of CD-PTT, the copolymerized sulfonic acid metal salts are ion-crosslinked to each other in a molten state, so that the melt viscosity is significantly increased. For this reason, there is a problem that the distillation of 1,3-propanediol is inhibited in the polycondensation reaction stage, and the degree of polymerization is hardly increased. Furthermore, CD-PTT has lower thermal stability at the time of melting than PET, polybutylene terephthalate, and homo-PTT having a similar structure, and does not increase the molecular weight even if the polycondensation time is prolonged. However, there is a problem in that depolymerization due to thermal decomposition occurs before the temperature is increased, and the polymer itself is also colored yellow, so that high-molecular-weight CD-PTT cannot be obtained.
The present inventors proceeded with the study of increasing the molecular weight of CD-PTT, and as a result, once produced a low-molecular-weight CD-PTT (hereinafter abbreviated as a prepolymer), and solid-phase polymerized the prepolymer. We have succeeded in obtaining CD-PTT having a high molecular weight that cannot be reached by melt polymerization. However, as a result of examining the melt polymerization characteristics, hue, and solid-phase polymerization characteristics in detail, there were the following problems in implementing this technology industrially.

That is, if the properties such as the amount of terminal carboxyl groups of the prepolymer formed by melt polymerization deviate from a specific range, the solid-state polymerization rate, the melt stability and the hue of the obtained high-molecular-weight CD-PTT significantly decrease. In particular, the amount of terminal carboxyl groups is closely related to the copolymerization ratio of the ester-forming sulfonic acid salt, the catalyst, the additives, the polycondensation reaction conditions, and the like. Therefore, the present inventors have newly found that these conditions must be precisely controlled in order to obtain a high-molecular-weight CD-PTT which is the object of the present invention.
On the other hand, in the case of fiberization, when a CD-PTT having a low molecular weight is used as a raw material, the tensile strength can be relatively increased by applying a high draw ratio after melt spinning. The fiber shrinkage increases due to stretching. When such a fiber with a high shrinkage rate is made into a fabric and subjected to post-processing such as dyeing, the fiber shrinks greatly and the fabric becomes hard, and the soft texture expected from the low elastic modulus of PTT can be sufficiently expressed. Can not.

Such a phenomenon rarely occurs in PET fibers having a structure similar to PTT. The reason is that while the molecular structure of PET is likely to have a stretched structure, PTT has a helical molecular structure, and in the case of PTT fiber, it is possible to stretch the molecule by stretching. This is because, when heated, the amorphous portion shrinks greatly and the molecule takes a stable helical structure, and as a result, the fiber shrinks greatly. In addition, soft texture can be given in consideration of the degree of shrinkage, but the weaving density and knitting density must be set very low when fabric is made, and the design is very difficult at present. Met.
A first object of the present invention is to produce a polymer having a high solid-state polymerization rate, a small rate of decrease in viscosity upon melting, suitable as a raw material of a PTT fiber capable of dyeing a cationic dye, and having a high molecular weight copolymer having an excellent hue. An object of the present invention is to provide a polymerized PTT and a method for producing the same.
A second object of the present invention is to provide a cationic dye-dyeable PTT fiber which has high toughness, does not largely shrink during dyeing or heat setting, and has excellent processing characteristics, and a method for producing the same.

The present inventors have studied in detail the melt polymerization characteristics and solid-state polymerization characteristics of CD-PTT. By setting the amount of the carboxyl group in a specific range, it has been found that the above problem can be solved. Furthermore, they have found the requirements for a polymer required to achieve good cationic dye dyeability and color fastness, and have reached the CD-PTT of the present invention.
Furthermore, the present inventors have extruded a specific range of high polymerization degree CD-PTT that can be uniformly extruded from a spinneret having a specific range of the spinneret surface temperature and the ambient temperature around the spinneret, and the orientation and crystallinity. By drawing the undrawn yarn with a low drawability and good drawability, stretching the undrawn yarn at a specific range of magnification, the fiber has high toughness, does not significantly shrink during dyeing or heat setting, and has excellent processing characteristics. It was found that the PTT fiber of the present invention was obtained.

That is, the present invention is as follows.
1. A copolymerized polytrimethylene terephthalate fiber satisfying the following (1) to (6).
(1) The ester-forming sulfonic acid salt is copolymerized in an amount of 0.5 to 5 mol% based on all dicarboxylic acid components.
(2) 0.1 to 2.5 wt% of bis (3-hydroxypropyl) ether is copolymerized.
(3) The intrinsic viscosity is 0.65 to 1.4 dl / g.
(4) The amount of terminal carboxyl groups is 5 to 40 meq / kg fiber or less.
(5) Toughness is 16 or more.
Here, toughness is a value calculated from the following equation.
Toughness = [strength (cN / dtex)] x [elongation (%)] ^1/2
(6) U% is 0 to 3%.
2. (1) characterized by satisfying the following (7) and (8). The copolymerized polytrimethylene terephthalate fiber according to the above.
(7) The peak temperature of the dynamic loss tangent is 105 to 140 ° C.
(8) The boiling water shrinkage is 0 to 16%.

3. (1) The toughness is 17.5 or more. Or 2. The copolymerized polytrimethylene terephthalate fiber according to the above.
4. A copolymer polytrimethylene terephthalate satisfying the following (a) to (d) is extruded from a spinneret at a spinning surface temperature of 250 to 295 ° C and a spinning draft represented by the following formula becomes 50 to 1500, After cooling and solidifying, the unstretched yarn having a breaking elongation of 200 to 400% and a crystallization peak temperature of 64 to 80 ° C. is taken at a speed of 100 to 3000 m / min, and the unstretched yarn is cooled to 45 to 80%. (1) stretching at a temperature of 100 ° C. at a stretching ratio of 60 to 90% of the maximum stretching ratio and heat-treating at a temperature of 100 to 160 ° C. ~ 3. The method for producing a copolymerized polytrimethylene terephthalate fiber according to any one of the above.
(A) 0.5 to 5 mol% of the ester-forming sulfonic acid salt is copolymerized with respect to all dicarboxylic acid components.
(B) 0.1 to 2.5 wt% of bis (3-hydroxypropyl) ether is copolymerized.
(C) The intrinsic viscosity is 0.65 to 1.5 dl / g.
(D) The amount of terminal carboxyl groups is not more than 25 meq / kg resin.
Spinning draft = (V2) / (V1)
V1: Linear velocity of polymer when extruded from spinneret (m / min)
V2: First roll speed (m / min) (take-up speed when the first roll is not used)

5. 3. The above-mentioned item 4, wherein the copolymerized polytrimethylene terephthalate is extruded from a spout provided with a heating cylinder having a length of 50 to 300 mm and a temperature of 150 to 350 ° C under the spout. A process for producing the copolymerized polytrimethylene terephthalate fiber according to the above.
6. 3. The above-mentioned item 4, wherein the undrawn yarn is once wound and then drawn. Or 5. 3. The method for producing a copolymerized polytrimethylene terephthalate fiber according to item 1.
7. 3. The drawn undrawn yarn is continuously drawn without being wound once. Or 5. 3. The method for producing a copolymerized polytrimethylene terephthalate fiber according to item 1.
8. The above 1. Or 2. A copolymerized polytrimethylene terephthalate staple fiber obtained by crimping the copolymerized polytrimethylene terephthalate fiber described in the above, having a fiber length of 3 to 300 mm and a degree of crimp of 5% or more. Short fibers of copolymerized polytrimethylene terephthalate, characterized by the following characteristics.
9. The above 1. Or 2. A fiber product using the copolymerized polytrimethylene terephthalate fiber described in 1 or 2 above in part or in whole.
10. 8 above. A fiber product using partially or entirely the short fiber of the copolymerized polytrimethylene terephthalate described in 1. above.

  A cationic dye-dyeable PTT fiber which has high toughness, does not largely shrink during dyeing or heat setting, and has excellent processing characteristics, and a method for producing the same can be provided.

The copolymerized PTT of the present invention is a polyester obtained by copolymerizing PTT with an ester-forming sulfonate in an amount of 0.5 to 5 mol%. Here, PTT is a polyester containing terephthalic acid as an acid component and 1,3-propanediol as a diol component. The ester-forming sulfonate serves as a seat for dyeing the cationic dye, and is an essential copolymer component for achieving the object of the present invention. For unknown reasons, the copolymerization of the ester-forming sulfonic acid salt has a surprising effect that the color is far superior to that of homo-PTT.
Examples of the ester-forming sulfonate used in the present invention include a compound containing a sulfonate group represented by the following general formula, which can be copolymerized with PTT and has a sulfonate moiety. If you do, there is no particular limitation. For example, instead of a metal salt, an organic salt such as a tetraalkylphosphonium salt or a tetraalkylammonium salt may be used. From the viewpoint that a PTT having a good hue is obtained, a metal salt represented by the following formula is preferable.

式中、Ｒ¹ 、Ｒ² は、−ＣＯＯＨ、−ＣＯＯＲ、−ＯＣＯＲ、−（ＣＨ₂）_nＯＨ、−（ＣＨ₂）_n〔Ｏ（ＣＨ₂）_m〕_pＯＨ、または、−ＣＯ〔Ｏ（ＣＨ₂）_n〕_mＯＨ、であり、Ｒ¹、Ｒ²は同一の基でも、相異なる基でもよい。Ｒは炭素数１〜１０のアルキル基であり、ｎ、ｍ、ｐは１以上の整数である。Ｍは金属、好ましくはアルカリ金属、アルカリ土類金属である。Ｚは炭素数１〜３０までの３価の有機基で、好ましくは３価の芳香族基である。

In the formula, R ¹ and R ² represent —COOH, —COOR, —OCOR, — (CH ₂ ) _n OH, — (CH ₂ ) _n [O (CH ₂ ) _m ] _p OH, or —CO [O (CH ₂ ) _n ] _m OH, and R ¹ and R ² may be the same or different groups. R is an alkyl group having 1 to 10 carbon atoms, and n, m, and p are integers of 1 or more. M is a metal, preferably an alkali metal or an alkaline earth metal. Z is a trivalent organic group having 1 to 30 carbon atoms, preferably a trivalent aromatic group.

Specific examples of preferred ester-forming sulfonate compounds include 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 2-potassium sulfoterephthalic acid, -Sodium sulfo-2,6-naphthalenedicarboxylic acid, 2-sodium sulfo-4-hydroxybenzoic acid, and the like, and ester derivatives such as methyl ester and dimethyl ester thereof. In particular, these ester derivatives such as methyl ester and dimethyl ester are preferably used in that the polymer has excellent whiteness and polymerization rate.
The copolymerization ratio of the ester-forming sulfonic acid salt needs to be 0.5 to 5 mol% based on the total number of moles of all dicarboxylic acid components constituting the polyester. When the copolymerization ratio of the ester-forming sulfonate compound is less than 0.5 mol%, the color developability when dyed with a cationic dye is reduced. On the other hand, when the proportion of the ester-forming sulfonate compound exceeds 5 mol%, the heat resistance of the polymer is deteriorated, the polymerizability and the spinnability are extremely deteriorated, and the fiber is liable to yellow. From the viewpoint of having both polymerizability and spinnability while sufficiently maintaining the dyeability for the cationic dye, the amount is preferably 1 to 3 mol%, particularly preferably 1.2 to 2.5 mol%.

Furthermore, the CD-PTT of the present invention requires that bis (3-hydroxypropyl) ether (hereinafter, abbreviated as BPE) is copolymerized in an amount of 0.1 to 2.5 wt% based on the mass of the polymer. is there. BPE is a chemical substance represented by the following structural formula.
HOCH ₂ CH ₂ CH ₂ OCH ₂ CH ₂ CH ₂ OH
BPE is a substance produced by dehydration and dimerization of 1,3-propanediol which is a raw material of CD-PTT.
In the production of homo-PTT, when polymerization is performed using a lower alcohol ester of terephthalic acid such as dimethyl terephthalate as a raw material, usually less than 0.1 wt% of BPE is by-produced and copolymerized with the polymer. When polymerization is performed using terephthalic acid as a raw material, 0.3 wt% or more of BPE is copolymerized with the polymer because protons of terephthalic acid serve as a catalyst for dimerization of 1,3-propanediol. On the other hand, during the production of CD-PTT, the ester-forming sulfonic acid salt also serves as a catalyst for BPE generation, and the copolymerization ratio of BPE is higher than that of homo-PTT regardless of what terephthalic acid derivative is used as a raw material. Become. When the amount of BPE is increased, the melt stability, polymerization reactivity, and light resistance of the polymer are adversely affected. However, when the BPE is present in an appropriate amount, the effect of increasing the dye exhaustion rate during dyeing and facilitating alkali weight reduction processing is exerted. Therefore, precise control of the amount of BPE is important in polymer design.
If BPE is less than 0.1 wt%, the melting point is high and the melt stability is high, but there is a drawback that the exhaustion rate of the cationic dye is slightly lower. If it exceeds 2.5 wt%, the melting point will be low, the thermal stability will be low, and the light resistance will be low. The copolymerization ratio of BPE varies depending on the starting carboxylic acid derivative used, but is preferably 0.1 to 0.4 wt% in the case of a lower alcohol ester of terephthalic acid, and 0.4 to 2.5 wt% in the case of using terephthalic acid. It is preferably 0.11 to 2.2 wt%, more preferably 0.15 to 1.8 wt%, from the preferable balance between the thermal stability, light resistance and dye exhaustion of the fiber.

  A component other than the ester-forming sulfonate may be copolymerized with the CD-PTT of the present invention as long as the object of the present invention is not impaired. Examples of such a copolymer component include 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentamethylene glycol, and 1,6-hexamethylene. Glycol, heptamethylene glycol, octamethylene glycol, decamethylene glycol, dodecamethylene glycol, 1,4-cyclohexanediol, 1,3-cyclohexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,3 -Cyclohexanedimethanol, 1,2-cyclohexanedimethanol, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, heptandioic acid, octanedioic acid, sebacic acid, dodecanedioic acid, 2-methylglutaric acid, -Methyl adipic acid, fumaric , Maleic acid, itaconic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, isophthalic acid, polyethylene glycol having a molecular weight of 400 to 100,000, and polytetramethylene having a molecular weight of 400 to 100,000 Glycol and the like. The copolymerization ratio varies depending on the copolymerization component, but is usually 10% by weight or less based on the mass of the polymer.

Further, if necessary, various additives may be added to the CD-PTT of the present invention, for example, matting agents such as titanium oxide, heat stabilizers, defoaming agents, tinting agents, flame retardants, antioxidants, ultraviolet absorbers. , An infrared absorber, a crystal nucleating agent, a fluorescent whitening agent, and the like may be copolymerized or mixed. In particular, when using titanium oxide as a matting agent, the amount is preferably 0.01 to 0.1 wt% per mass of the polymer.
The CD-PTT of the present invention needs to have an intrinsic viscosity of 0.65 to 1.5 dl / g. When the intrinsic viscosity is less than 0.65 dl / g, the strength of the obtained fiber is low. On the other hand, when the intrinsic viscosity exceeds 1.5 dl / g, the melt viscosity is too high, so that the metering by the gear pump is not performed smoothly, and the spinnability is reduced due to poor discharge or the like. It is preferably 0.7 to 1.5 dl / g, particularly preferably 0.85 to 1.25 dl / g, and a CD-PTT having excellent strength and spinnability can be obtained.

The CD-PTT of the present invention needs to have a terminal carboxyl group content of 25 meq / kg resin or less. Here, the milliequivalent / kg resin indicates the amount of terminal carboxyl groups per 1 kg of CD-PTT. Also, the unit of milliequivalent / kg fiber indicates the amount of terminal carboxyl groups per kg of CD-PTT fiber. If the amount of the terminal carboxyl group exceeds 25 meq / kg resin, the melt stability becomes insufficient or the strength tends to decrease during the treatment with a heated aqueous solution such as dyeing. Preferably, it is 2 to 25 meq / kg resin, more preferably 2 to 20 meq / kg resin, and most preferably 2 to 15 meq / kg resin.
The L-value of the CD-PTT of the present invention is preferably 70 or more, more preferably 80 or more, from the viewpoint of achieving vivid color development when dyed with a cationic dye. Further, from the viewpoint of achieving vivid color development, the b ^* value is preferably -5 to 8, more preferably -2 to 6, and most preferably -1 to 5.
The melting point of the CD-PTT of the present invention is preferably 223 ° C. or higher, more preferably 225 ° C. or higher, from the viewpoint of melt stability.

A preferred method for producing the CD-PTT of the present invention will be described below.
The method for producing CD-PTT of the present invention will be described separately because the polymerization method is slightly different between using a lower alcohol ester of terephthalic acid and using terephthalic acid.
First, a case where a lower alcohol ester of terephthalic acid is used without substantially using terephthalic acid will be described.
The CD-PTT of the present invention is obtained by reacting a lower alcohol ester of terephthalic acid as a main dicarboxylic acid component with 1,3-propanediol as a main diol component to obtain 1,3-propanediol ester of terephthalic acid or / And its oligomers are generated, and then the polycondensation reaction is completed, and after the obtained polymer is once solidified, it is heated in a solid state, and at least the intrinsic viscosity is calculated from the intrinsic viscosity at the end of the polycondensation reaction. Can also be produced by a method of increasing 0.1 dl / g or more and by a polymerization method satisfying the following conditions (a) and (b).
(A) At any stage from the start of the reaction to the end of the polycondensation reaction, an ester-forming sulfonic acid salt in an amount corresponding to 0.5 to 5 mol% of the total dicarboxylic acid component is added.
(B) The amount of terminal carboxyl groups of the copolymerized PTT before the start of solid phase polymerization is 5 to 40 meq / kg resin or less.
The method for producing CD-PTT of the present invention comprises a transesterification reaction in which a lower alcohol ester of terephthalic acid is condensed with 1,3-propanediol to produce a 1,3-propanediol ester of terephthalic acid or / and an oligomer thereof. A polycondensation reaction step of obtaining a prepolymer while heating the obtained condensate to distill off 1,3-propanediol, and a solid phase polymerization step of the prepolymer.

First, the transesterification step will be described.
The charging ratio of 1,3-propanediol to the lower alcohol ester of terephthalic acid, which is a raw material for polymerization, is preferably 0.8 to 3 in molar ratio. When the charge ratio is less than 0.8, the transesterification reaction hardly proceeds, and when the charge ratio is more than 3, the melting point is lowered, and the whiteness of the obtained polymer tends to decrease. Preferably it is 1.4-2.5, More preferably, it is 1.5-2.3.
The catalyst is preferably used to make the reaction proceed smoothly, for example, titanium tetrabutoxide, titanium alkoxide represented by titanium tetraisopropoxide, amorphous titanium oxide precipitate, amorphous titanium oxide / Silica coprecipitates, metal oxides such as amorphous zirconia precipitates, metal carboxylate salts such as calcium acetate, manganese acetate, cobalt acetate, antimony acetate, etc. may be used in an amount of 0.01 to 0 with respect to all carboxylic acid component monomers. It is preferable to use 0.2 wt% because it has both the reaction rate, the whiteness of the polymer, and the thermal stability. Among these catalysts, a titanium compound, calcium acetate, and cobalt acetate are preferable in that the amount of insoluble foreign matter generated by reacting with the ester-forming sulfonate is small. The reaction can be performed at a reaction temperature of about 200 to 250 ° C. while distilling off by-product alcohol such as methanol. The reaction time is usually 2 to 10 hours, preferably 2 to 4 hours. The reaction product thus obtained contains 1,3-propanediol ester of terephthalic acid or / and an oligomer thereof.

After the transesterification reaction, a polycondensation reaction is performed. In the polycondensation reaction, if necessary, titanium tetrabutoxide, titanium alkoxide represented by titanium tetraisopropoxide, amorphous titanium oxide precipitate, amorphous titanium oxide / silica coprecipitate, amorphous A polycondensation reaction can be performed according to a known method by adding 0.01 to 0.2 wt% of a metal oxide such as a reactive zirconia precipitate to all the carboxylic acid component monomers.
In order to obtain CD-PTT having a high solid-state polymerization rate and excellent melt stability and hue, which is an object of the present invention, the amount of terminal carboxyl groups of the prepolymer at the time when the polycondensation reaction is completed is 5 to 40. It is necessary to be a milliequivalent / kg resin. If the amount exceeds 40 meq / kg resin, the solid-state polymerization rate is remarkably reduced, the stability at the time of melting is deteriorated, the molecular weight is easily reduced, and the hue of the obtained CD-PTT is also deteriorated. On the other hand, if the amount is less than 5 meq / kg resin, the amount of carboxyl groups capable of ester bonding is too small, and the solid-state polymerization rate decreases. Preferably, it is 5 to 35 meq / kg resin, and more preferably, 10 to 32 meq / kg resin.

  As a method for achieving such an amount of terminal carboxyl groups of the prepolymer, for example, at a polycondensation reaction temperature of 240 to 270 ° C., while evaluating the amount of terminal carboxyl groups of the prepolymer, the optimal polymerization time, usually It is to set the time within 4 hours, preferably in the range of 1 to 3 hours. The polycondensation temperature is preferably from 250 to 270 ° C, and the degree of vacuum is from 0.13 to 133 Pa. In order to efficiently remove 1,3-propanediol during polycondensation, it is important to increase the surface area of the polymer. For this purpose, for example, efficient stirring is performed using a helical stirrer or the like, and the ratio of charging the raw materials to the capacity of the kettle is preferably 70% or less, and more preferably 60% or less. Further, it is preferable to stop the polycondensation reaction while the viscosity of the melt in the polycondensation reaction step increases with time. It is important that the polycondensation reaction be completed before the melt viscosity does not increase or rather decreases even if the time is extended. This is because, if the melt viscosity does not increase or decreases even if the time is extended, the thermal decomposition reaction becomes superior to the polymerization reaction, and the amount of terminal carboxyl groups generated by the thermal decomposition increases.

The addition of the ester-forming sulfonate can be carried out at any stage from the start of the transesterification reaction to the end of the polycondensation reaction, in which case it is substantially copolymerized with CD-PTT. The addition amount is 0.5 to 5 mol% of the total dicarboxylic acid component for the same reason as described above.
The method of adding the ester-forming sulfonic acid salt may be added as it is, or may be added after dissolving it in a suitable solvent. Particularly preferably, it is added by dissolving in 1,3-propanediol. However, when dissolved in a solvent such as 1,3-propanediol, which is preferable from the viewpoint of easiness of addition and accuracy of measurement, it is preferable to reduce the amount of the solvent as much as possible from the viewpoint of preventing a decrease in the melting point. When dissolving, heating may be performed. It may be reacted with 1,3-propanediol at the stage of dissolution, and for that purpose, known transesterification catalysts such as lithium, calcium, cobalt, manganese, titanium, antimony, zinc, carboxylate salts such as tin, Titanium alkoxide and an amorphous metal oxide salt may be added in an amount of 0.01 to 200% by weight based on the ester-forming sulfonate.

For example, when dimethyl 5-sodium sulfoisophthalate is used as the ester-forming sulfonate, monosodium 5-sodium sulfoisophthalate (1,3-propanediol) and 5-sodium sulfoisophthalate in 1,3-propanediol are used. It may be changed to bis (1,3-propanediol) isophthalate, monomethyl mono (1,3-propanediol) 5-sodium sulfoisophthalate, or a trace amount contained in 1,3-propanediol. It may be hydrolyzed by water to 5-sodium sulfoisophthalic acid or its monomethyl ester.
In the method for producing CD-PTT of the present invention, as a method for reducing the amount of terminal carboxyl groups, heat stability, melt stability and increasing the whiteness of the polymer, the above-mentioned preferable amount of catalyst, reaction temperature and the like are applied, It is particularly preferred to add a heat stabilizer and a color inhibitor at any stage of the polymerization.

  As the heat stabilizer, a pentavalent or trivalent phosphorus compound or a hindered phenol-based antioxidant is preferable. For example, the pentavalent or trivalent phosphorus compound includes trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, phosphoric acid, phosphorous acid, and the like. Hindered phenolic antioxidants include pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and 1,1,3-tris (2-methyl-4-). (Hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,9-bis} 2- [3- (3-tert-butyl-4-hydroxy-5-methyl [Phenyl] propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,3,5-tris (4-tert-butyl-3-hydroxy- 2,6-dimethylbenzene) isophthalic acid, triethylglycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3 5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylene-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and the like.

The addition amount is preferably from 0.01 to 0.5 wt%, more preferably from 0.02 to 0.1 wt%, based on the CD-PTT. Even in this range, the rate of the polycondensation reaction or the solid-state polymerization reaction may decrease when the amount of the heat stabilizer is increased due to the relationship between the amount of the catalyst and the amount of the catalyst. It is preferable to set above. A person skilled in the art can determine such a quantitative ratio without any difficulty.
Examples of the coloring inhibitor include a cobalt compound such as cobalt acetate and cobalt formate, a commercially available fluorescent whitening agent, and the like, and 0.0001 to 0.1 wt% of CD-PTT can be added. These additives can be added at any stage of the polymerization.

Further, in order to reduce insoluble aggregates formed by modification of the catalyst, heat stabilizer and a small amount of the ester-forming sulfonic metal salt, lithium acetate, lithium carbonate, lithium formate, sodium acetate, sodium carbonate, sodium formate are used. It is preferable to add an alkali metal salt such as sodium hydroxide, calcium hydroxide, magnesium hydroxide and / or an alkaline earth metal salt at any stage of the polymerization. Is preferably 1 to 100 mol%, more preferably 1 to 20 mol%. The use of alkali metal salts is particularly preferred, and the use of lithium salts and hydroxide salts is particularly preferred.
If the amount of infusible agglomerates is large, the pressure inside the spinning pack will increase and the yarn breakage will easily occur, or the frequency of replacing the spinning pack to prevent it will increase, reducing productivity. However, this problem can be avoided by using the above additive. The addition of the alkali metal salt can be added at any stage of the polymerization, but it is preferable to add the alkali metal salt at the end of the transesterification reaction in order to achieve the effect. It is particularly preferred to add them simultaneously.

It is necessary to increase the intrinsic viscosity of the prepolymer obtained as described above by solid phase polymerization. In particular, it is difficult to increase the intrinsic viscosity to 0.65 or more without performing solid-state polymerization. This is because if the reaction temperature of the polycondensation is raised to increase the intrinsic viscosity, thermal decomposition may occur and the viscosity may not be increased. By performing solid-phase polymerization, the intrinsic viscosity can be easily increased to 0.65 or more without lowering the melt stability or hue. Solid-state polymerization is a process in which a prepolymer in the form of a chip, a powder, a fiber, a plate, or a block is formed in the presence of an inert gas such as nitrogen or argon, or 1.33 × 10 ⁴ Pa or less, preferably The reaction can be performed under reduced pressure of 1.33 × 10 ³ Pa or less at 170 to 220 ° C. for about 3 to 48 hours.
The advantage of performing solid-phase polymerization is that the intrinsic viscosity can be increased, and the oligomer having sublimability escapes from the polymer during the solid-phase polymerization, so that the amount of the cyclic or linear oligomer in the polymer is reduced to 2 wt. %, Preferably 1% by weight or less. Further, as long as the prepolymer obtained by the method of the present invention is used, the hue of CD-PTT hardly deteriorates due to solid-phase polymerization. Further, the amount of terminal carboxyl groups can be greatly reduced with respect to the prepolymer obtained by melt polymerization, and as a result, CD-PTT having excellent melt stability and whiteness can be obtained.

Next, a preferred production method when terephthalic acid is used will be described.
The CD-PTT of the present invention reacts terephthalic acid, which is a main dicarboxylic acid component, with 1,3-propanediol, which is a main diol component, to form a 1,3-propanediol ester of terephthalic acid or / and an oligomer thereof. After completion of the polycondensation reaction, the obtained polymer is once solidified, and then heated in a solid state, so that the intrinsic viscosity is at least 0.1 dl / l less than the intrinsic viscosity at the end of the polycondensation reaction. g or more, and satisfying the following conditions (a) to (c): can be produced by a method for producing copolymerized polytrimethylene terephthalate.
(A) The molar ratio of 1,3-propanediol to terephthalic acid is 0.8 to 2.5.
(B) In the reaction between terephthalic acid and a diol mainly composed of 1,3-propanediol, the reaction rate of terephthalic acid is 75 to 100%, which corresponds to 0.5 to 5 mol% of the total dicarboxylic acid component. Add the amount of ester-forming sulfonate.
(C) The amount of terminal carboxyl groups of the copolymerized polytrimethylene terephthalate before the start of solid phase polymerization is 5 to 40 meq / kg resin.
In the method for producing CD-PTT of the present invention, an esterification reaction in which terephthalic acid and 1,3-propanediol are condensed to produce 1,3-propanediol ester of terephthalic acid or / and an oligomer thereof is obtained. The method comprises a polycondensation reaction for obtaining a prepolymer while heating the condensate to distill off 1,3-propanediol, and a method for solid-state polymerization of the prepolymer.

First, the esterification reaction will be described.
The charge ratio of 1,3-propanediol to terephthalic acid, which is a polymerization raw material, needs to be 0.8 to 2.5 in molar ratio. If the charging ratio is less than 0.8, the esterification step does not proceed completely. On the other hand, when the charging ratio is larger than 2.5, the melting point is lowered and the whiteness of the obtained polymer is lowered. Preferably it is 0.8-1.5, More preferably, it is 1-1.3.
The type and amount of the catalyst preferably used for smoothly proceeding the esterification reaction, the conditions of the esterification reaction, and the like are the same as those in the case of the transesterification reaction using the lower alcohol ester of terephthalic acid described above. . In this case, what is distilled out of the reaction system is water.

The addition of the ester-forming sulfonate is carried out in an amount corresponding to 0.5 to 5 mol% of the total dicarboxylic acid component at a stage where the conversion of the esterification reaction, that is, the conversion of terephthalic acid is 75 to 100%. The addition of an ester-forming sulfonate is a necessary condition for obtaining the CD-PTT of the present invention. If the reaction rate is less than 75%, the copolymerization ratio of BPE will increase, and will fall outside the scope of the present invention. This is because when the conversion is low, the amount of unreacted terephthalic acid-derived protons is large, which accelerates the production of BPE. The addition is preferably performed at a reaction rate of 90% or more, and most preferably performed after the esterification reaction is completed at 95% or more. As a method for adding the ester-forming sulfonate, the same method as when using the lower alcohol ester of terephthalic acid can be applied.
After the esterification reaction, a polycondensation reaction and solid-phase polymerization are performed.The conditions are the same as those for the polycondensation reaction using the lower alcohol ester of terephthalic acid described above. Can be used.
The high molecular weight CD-PTT obtained as described above can be dyed with a cationic dye by a known spinning method because the raw material polymer is excellent in whiteness, and is far more than a known CD-PTT fiber. Fibers exhibiting excellent coloring and sharpness. In particular, by performing the following specific spinning, a fiber having high toughness aimed at by the present invention and excellent in processability which does not excessively shrink during processing is obtained.

That is, the preferred CD-PTT fiber of the present invention is composed of polytrimethylene terephthalate in which the ester-forming sulfonic acid salt is copolymerized in an amount of 0.5 to 5 mol% with respect to all dicarboxylic acid components, and PTT fiber satisfying (C).
(A) Intrinsic viscosity: 0.65 to 1.4 dl / g
(B) Peak temperature of dynamic loss tangent: 105-140 ° C
(C) Boiling water shrinkage: 0 to 16%
The intrinsic viscosity of the CD-PTT fiber of the present invention needs to be 0.65 to 1.4 dl / g. When the intrinsic viscosity is in this range, a fiber having high toughness is obtained for the first time. If the intrinsic viscosity is less than 0.65 dl / g, satisfactory toughness cannot be achieved because the polymerization degree is too low. On the other hand, if the intrinsic viscosity exceeds 1.4 dl / g, the melt viscosity is too high at the time of spinning, so that melt fracture or the like occurs, and the fiber does not become uniform. As a result, the toughness is rather reduced. Further, even if the spinning conditions are adjusted, it is difficult to reduce the molecular tension, and the boiling water shrinkage rate increases. The intrinsic viscosity of the fibers is preferably from 0.68 to 1.3 dl / g, particularly preferably from 0.7 to 1.2 dl / g.

The peak temperature of the dynamic loss tangent (hereinafter, abbreviated as Tmax) of the CD-PTT fiber of the present invention needs to be 105 to 140 ° C. Tmax is a value obtained from dynamic viscoelasticity measurement, and corresponds to the denseness of molecules in an amorphous part. As this value increases, it indicates that the amorphous portion has a dense structure. When Tmax is less than 105 ° C., the amorphous portion has low density, the orientation of molecules in the fiber axis direction is poor, the toughness of the fiber is small, and the fiber may be easily broken when formed into a fabric. On the other hand, if the temperature exceeds 140 ° C., the denseness of the molecules in the amorphous portion becomes too high, so that the cationic dye becomes difficult to enter, and the dyed product may not develop a dark color. Tmax is particularly preferably 110 to 120 ° C. in consideration of toughness and color development of the dyed product.
The boiling water shrinkage (hereinafter abbreviated as BWS) of the CD-PTT fiber of the present invention needs to be 0 to 16%. When the BWS exceeds 16%, the molecules are in an excessively tensed state, and when the resulting fabric is heat-treated by post-processing such as dyeing, the fabric shrinks greatly, and the fabric is hard and stiff. In some cases, the soft texture inherent in the PTT fiber may not be exhibited. On the other hand, when the fiber is less than 0%, that is, when the fiber is stretched in boiling water, a post-treatment such as heat setting may not be able to obtain a wrinkle-free fabric. BWS is more preferably 3 to 15%, and still more preferably 5 to 14%.

The breaking elongation of the CD-PTT fiber of the present invention is preferably 20 to 70%. The elongation at break is preferably 20% or more from the viewpoint of improving the toughness of the fiber and suppressing the generation of fluff or yarn breakage during stretching or post-processing. Further, the elongation at break is preferably 70% or less from the viewpoint that the toughness of the fiber is improved and the fiber is uniformly stretched to obtain a fiber having a small thickness unevenness. The more preferable range of the elongation at break is 25 to 65%, further preferably 30 to 60%, and particularly preferably 35 to 55%. The toughness of the CD-PTT fiber of the present invention is preferably 16 or more. Here, toughness is a value calculated from the following equation.
Toughness = [strength (cN / dtex)] x [elongation (%)] ^1/2
When the toughness is 16 or more, the obtained fabric is difficult to tear. The upper limit of toughness is not particularly limited, and the higher the better, the better. In order to make full use of the effect of the high molecular weight of the CD-PTT of the present invention and sufficiently exhibit the durability and toughness of the obtained fiber product, the toughness is preferably 17.5 or more, more preferably 18 or more. Above, most preferably 19 or more.

The breaking strength of the CD-PTT fiber of the present invention is preferably 2.2 cN / dtex or more. If it is less than 2.2 cN / dtex, the strength is low. Therefore, in order to increase the toughness, it is necessary to increase the elongation, and when a fabric is formed, the part to which the force is applied remains deformed. Dropouts are likely to occur. The breaking strength is more preferably at least 2.4 cN / dtex, still more preferably at least 2.6 cN / dtex, particularly preferably at least 2.8 cN / dtex.
The elastic recovery of the CD-PTT fiber of the present invention at 20% elongation is preferably 60% or more in order to achieve the excellent stretch property inherent in PTT. It is more preferably at least 65%, particularly preferably at least 70%.
The density of the CD-PTT fiber of the present invention is preferably 1.330 g / cm ³ or more. The density is an index indicating the crystallinity of the fiber. The higher the density, the higher the crystallinity. In order to sufficiently increase the crystallinity and exhibit the excellent stretch property peculiar to PTT, and to sufficiently fix the molecules by crystallization to make the BWS within the preferred range of the present invention, the density is 1.330 g. / Cm ³ or more. On the other hand, since the crystal density of PTT is 1.431 g / cm ³ (material, see Vol. 35, No. 396, p. 1067, published in 1986), the upper limit of the density of the copolymerized CD-PTT is obtained. Is not expected to exceed this value. The density is more preferably 1.335 g / cm ³ or more, and still more preferably 1.340 g / cm ³ or more.
The U-% of the CD-PTT fiber of the present invention is preferably 0 to 3%.

When the fiber is passed through the USTER TESTER 3 at a constant speed, an uneven curve (mass change of the fiber) as shown in FIG. 1 is obtained. From this result, U% can be obtained according to the following equation (1). U% is preferably 2% or less, more preferably 1.5% or less, from the viewpoint of suppressing fluff and yarn breakage during post-processing and suppressing mechanical property unevenness and dye unevenness.
U% = [a / (Xave × T)] × 100 (1)
In FIG. 1, Xave represents the average value, a represents the area between the instantaneous mass value (Xi) and Xave (shaded portion), and T represents the measurement time in FIG.
The hue of the CD-PTT fiber of the present invention preferably has a YI value (yellowness) of -30 to 5 and a WI value (whiteness) of 50 to 150. When the hue is in this range, it becomes easy to obtain a fabric of a desired color or to obtain excellent coloring properties when dyeing a light color. In order to obtain a hue in such a range, the whiteness of the polymer is set to the b ^* and L values in the range of the present invention, and melting, extrusion temperature and the like are within the range of the present invention, and coloring due to thermal decomposition is suppressed. It is important to. The YI value is more preferably -20 to 4.5, and further preferably -10 to 3. Further, the WI value is more preferably 60 to 100, and further preferably 70 to 90.

The CD-PTT fiber of the present invention can take any form, such as a multifilament, a staple, a short fiber, a spun yarn, a monofilament, or the like depending on the use. For example, a processed yarn such as a false twist yarn or a twist yarn may be used. The total fineness is not particularly limited, but is usually 5 to 1000 dtex, preferably 10 to 300 dtex, and the single yarn fineness is not particularly limited, but is usually 0.1 to 20 dtex, preferably 0.5 to 10 dtex, and more preferably 1 to 5 dtex. is there. In particular, in the case of a monofilament, it is desirable to appropriately select from 5 to 10,000 dtex depending on the application.
The cross-sectional shape of the fiber is not particularly limited, such as round, triangular, other polygonal, flat, L-shaped, W-shaped, cross-shaped, well-shaped, dogbone-shaped, and may be a solid fiber or a hollow fiber. Is also good. Further, as long as the object of the present invention is not impaired, by using two or more kinds of polymers within the scope of the present invention having different matting agent contents and limiting viscosities, a sheath core, side-by-side, a laminated structure, etc. It may be a composite fiber or a composite fiber having a different cross-sectional shape or polymer type.

The CD-PTT fiber of the present invention may be wound in any form such as a pan or cheese-like package.
In the case of a cheese-like package, the bulge ratio is preferably 20% or less. FIG. 2A shows a cheese-like package (100) with the yarn wound into a desired shape. The yarn is wound on a cylindrical yarn layer (104) having a flat end surface (102) formed on a winding core (103) such as a yarn tube. As shown in FIG. 2B, the bulge is a bulging end surface (102a) of the cheese-like package (100) that is generated when the winding thread slides due to a strong tightening force due to shrinkage of the winding thread. The bulge ratio is a value obtained by measuring the winding width Q of the innermost layer and the winding width R of the most bulging portion shown in FIG. is there.
Bulge rate (%) = {(RQ) / Q} × 100

A cheese-like package having a bulge ratio of 20% or less can be easily achieved by setting the intrinsic viscosity, Tmax, and BWS within the range of the present invention. When the bulge ratio of the cheese-like package exceeds 20%, the winding yarn collapses during transportation and cannot be unwound, and yarn breakage, fluff, and stain spots due to uneven unwinding tension easily occur. In the worst case, the end face protrudes beyond the thread tube and cannot be transported. Further, since the tightening of the winding is increased, it is often impossible to remove the winding from the spindle of the winding machine.
The bulge ratio is preferably 15% or less, more preferably 10% or less, and most preferably 0%.
The cheese-like package preferably has a winding width Q of 40 to 300 mm and a diameter of the yarn tube of 50 to 250 mm in order to reduce the tension when unwinding the fiber and suppress the fluctuation of the tension.

Next, a preferred method for producing the CD-PTT fiber of the present invention will be described.
Basically, in the CD-PTT fiber of the present invention, the ester-forming sulfonic acid salt is copolymerized in an amount of 0.5 to 5 mol% with respect to all dicarboxylic acid components, and has an intrinsic viscosity of 0.65 to 1. When melt-spinning 5 dl / g of polytrimethylene terephthalate, the polytrimethylene terephthalate is extruded from the spinneret at a spinneret surface temperature of 250 to 295 ° C., solidified by cooling, and then at a speed of 100 to 3000 m / min. The undrawn yarn obtained by drawing is drawn at a temperature of 30 to 90 ° C at a draw ratio of 30 to 99% of the maximum draw ratio, and heat-treated at a temperature of 100 to 200 ° C. Most preferably, the CD-PTT uses the CD-PTT described in claim 1 of the specification of the original application of the present invention.
In the method for producing a CD-PTT fiber according to the present invention, a conventional method (hereinafter, referred to as a conveyor method) in which the drawn undrawn yarn is once wound and then drawn, or a so-called spin draw in which the undrawn yarn is continuously drawn without being wound once Any of the take-up method (hereinafter abbreviated as SDTU method) may be used. Withdrawing the undrawn yarn refers to winding by the winding machine 12 shown in FIG. 3 in the conveyor method, and refers to winding up to the first roll 18 shown in FIG. 5 in the SDTU method. Since the conveyor method and the SDTU method are the same from the drying to the drawing of the undrawn yarn, the explanation will be made with reference to FIG.

The CD-PTT dried in the dryer 1 to a water content of 100 ppm or less is supplied to the extruder 2 set at 250 to 290 ° C. and melted. The melted CD-PTT is sent to the spin head 4 set at 250 to 295 ° C., and measured by a gear pump. After that, it is extruded from a spinneret 6 having a plurality of holes attached to the spinneret pack 5. The water content of the CD-PTT supplied to the extruder is preferably 50 ppm or less, more preferably 30 ppm or less, from the viewpoint of suppressing a decrease in the degree of polymerization of the polymer.
A first important point for producing the CD-PTT fiber of the present invention is to obtain an undrawn yarn having a high degree of polymerization, low orientation and crystallinity, and good stretchability.

In order to obtain an undrawn yarn having a high degree of polymerization, a polymer having a high molecular weight and excellent melt stability such as the CD-PTT of the present invention is used, and the melting temperature is lowered so that the degree of polymerization does not decrease. Therefore, it is desirable to suppress the decomposition of the polymer. When the decomposition is severe, there is also an undesired problem that the fibers are colored. On the other hand, in order to obtain an undrawn yarn having good drawability, it is necessary to raise the melting temperature to completely melt the polymer and sufficiently unravel the entanglement of the molecular chains that hinders drawing. In particular, in the case of a polymer having a high degree of polymerization, entanglement is severe, and therefore, it is desirable to increase the melting temperature.
In order to achieve both, it is desirable to select a specific range of temperature conditions. That is, the temperature of the extruder is preferably from 250 to 280 ° C, more preferably from 255 to 275 ° C, still more preferably from 260 to 270 ° C, and the temperature of the spin head is preferably from 260 to 295 ° C, more preferably from 265 to 290 ° C. The temperature is more preferably 270 to 285 ° C., and the temperature of the spin head is preferably higher than the temperature of the extruder, and more preferably 5 ° C. or more. Since the temperature of the spin head is closely related to the spinning surface temperature, which will be described later, it is desirable to select the temperature from the above range so that the spinning surface temperature is in an appropriate range.

Next, in the case of CD-PTT having a high degree of polymerization, since the interaction between the molecules is strong, the molecules are easily oriented from the time of extruding the polymer to the time of cooling and solidifying to take up the fiber, so that the orientation of the molecules is suppressed. It is necessary to lower the degree of orientation of the undrawn yarn. This is a very important point in the present invention. In order to reduce the degree of orientation of the undrawn yarn, it is necessary to keep the polymer under the spinneret in a state in which there is little intermolecular interaction and to suppress sudden deformation of the molecule. For this purpose, it is necessary to raise the temperature of the spinning surface to raise the temperature of the extruded polymer, to slowly solidify the extruded polymer, and to reduce the thinning rate of the polymer, that is, the deformation rate.
Therefore, in the present invention, it is one of the important points to keep the spinning surface temperature in a specific temperature range of 250 to 295 ° C. If the spinning surface temperature is lower than 250 ° C., problems such as yarn breakage, frequent fluffing, and yarn unevenness occur. On the other hand, when the spinning surface temperature exceeds 295 ° C., the thermal decomposition becomes severe, and the degree of polymerization of the undrawn yarn is reduced or the undrawn yarn is colored. The spinning surface temperature is preferably from 255 to 290C, more preferably from 260 to 285C.

In order to achieve such a spinning surface temperature, it is preferable to set the spin head temperature to an appropriate value and to install a heating cylinder immediately below the spinning nozzle. If the spin head temperature is set too high in order to increase the spinning surface temperature, thermal decomposition will be severe and the resulting fiber will be colored or the degree of polymerization will be reduced. By using the heating tube, thermal decomposition of the polymer can be suppressed, and the temperature of the spinning surface and the atmosphere under the spinning can be increased, so that the extruded polymer can be prevented from being rapidly cooled and solidified.
The heating cylinder temperature is preferably from 100 to 350C, more preferably from 150 to 300C, and particularly preferably from 260 to 250C. The length of the heating cylinder is preferably from 50 to 300 mm, more preferably from 100 to 250 mm, in view of the effect of loosening the entanglement of the polymer molecules and the workability of spinning.

To reduce the deformation rate of the polymer, it is also preferable to lower the draft. The draft at the time of spinning is preferably in the range of 10 to 2000. Here, the spinning draft is a value represented by the following equation.
Spinning draft = (V2) / (V1)
Here, V1 is the linear velocity (m / min) of the polymer when extruded from the spinneret, and V2 is the first roll velocity (m / min) (the winding velocity when the first roll is not used). It is.
If the draft is less than 10, the extrusion pressure becomes too high because the spinning diameter becomes too small, and melt fracture or the like occurs, making it difficult to uniformly extrude. If the draft exceeds 2,000, the deformation rate of the polymer increases, and the degree of orientation of the undrawn yarn tends to increase. The spinning draft is more preferably from 50 to 1500, further preferably from 100 to 1000, particularly preferably from 150 to 500.

The spinner used in the present invention preferably has a diameter of 0.2 to 0.7 mm and a ratio of diameter to length of 1: 0.25 to 1: 3. If the diameter is less than 0.2 mm or the ratio of the diameter to the length exceeds 3, the extrusion pressure increases and melt fracture or the like occurs, making it difficult to extrude uniformly. On the other hand, if the diameter exceeds 0.7 mm, the fiber unevenness tends to increase, or the draft becomes high, whereby the fiber is oriented, and the drawability may decrease. If the ratio of the diameter to the length is less than 0.25, the spinning may be deformed or chipped over a long period of time. The diameter of the spinneret is more preferably 0.25 to 0.6 mm, even more preferably 0.3 to 0.5 mm. Further, the ratio between the diameter and the length is more preferably 1: 0.5 to 1: 2, and still more preferably 1: 0.75 to 1: 1.5.
The polymer extruded from the spinneret is cooled and solidified into fibers. The cooling is preferably performed by blowing cold air at 0 to 40 ° C. onto the polymer.
The cooled and solidified fiber may be directly wound up, but may be wound up by a winder via a first take-up roll or the like shown in FIG. 3 or may be taken up by a first roll shown in FIG. Preferably, stretching is performed.

In the present invention, it is also an important point that the speed at which the undrawn yarn is wound or the speed at which the undrawn yarn is taken up by a roll or the like is set to 100 to 3000 m / min. It means both the speed at which the yarn is wound and the speed at which the yarn is taken up by a roll or the like) By setting the take-up speed within this range, it becomes easy to suppress the orientation of the undrawn yarn. Since the extruded polymer falls under its own weight, it is difficult to make the take-off speed less than 100 m / min. On the other hand, if the take-up speed exceeds 3000 m / min, the deformation speed of the polymer increases and the air resistance increases, so that it is difficult to suppress the orientation of the undrawn yarn.
The take-up speed is preferably 300 to 2000 m / min, more preferably 600 to 1600 m / min, and particularly preferably 800 to 1200 m / min.

The undrawn yarn in the present invention preferably has an elongation at break of 150 to 600% and a crystallization peak temperature of 64 to 80 ° C. If the elongation at break is less than 150%, the entanglement of the molecules is so severe that it tends to be difficult to sufficiently orient the fiber by stretching and increase the breaking energy. On the other hand, when the elongation at break exceeds 600%, the undrawn yarn becomes brittle, and there is a tendency that it becomes difficult to stably draw the yarn due to yarn breakage. The elongation at break is more preferably from 180 to 500%, particularly preferably from 200 to 400%.
On the other hand, the crystallization peak temperature is the temperature of the peak of the crystallization peak observed when the undrawn yarn is subjected to thermal analysis at 20 ° C./min using an input compensation type differential scanning calorimeter. As the molecular regularity of the undrawn yarn increases, the crystallization peak temperature decreases due to crystallization at a lower temperature. In the present invention, since it is desirable to perform stretching at as high a magnification as possible without causing crystallization, the crystallization peak temperature is preferably as high as possible. If the crystallization peak temperature is lower than 64 ° C., crystallization occurs immediately during stretching, and it tends to be difficult to perform high-magnification stretching. With CD-PTT, the crystallization peak temperature does not exceed 80 ° C. The crystallization peak temperature is more preferably 66 to 80 ° C, still more preferably 68 to 80 ° C.

  It is preferable that the finishing agent is applied by the finishing agent applying device 9 before the cooled and solidified fiber is taken out. By providing the finishing agent, the fiber convergence, antistatic properties, slipperiness, and the like are improved, and the generation of fluff and yarn breakage during winding or post-processing can be suppressed. Here, the finishing agent is a water emulsion liquid obtained by emulsifying an oil agent using an emulsifier, a solution in which the oil agent is dissolved in a solvent, or the oil itself, which improves fiber convergence, antistatic properties, slipperiness, and the like. is there. Here, the oil agent is preferably a mixture containing at least one kind of an aliphatic ester, a mineral oil, and a polyether having a molecular weight of 1,000 to 20,000, and the sum of these is preferably 40 to 90 wt%. Is preferred.

In the present invention, the oil agent is preferably applied to the fiber as a water emulsion liquid having a concentration of 1 to 50% by weight. By using the water emulsion liquid, it becomes easy to suppress uneven adhesion of the oil agent and to improve the wound yarn form. The concentration of the water emulsion is more preferably 5 to 40 wt%, particularly preferably 10 to 30 wt%. When the concentration of the oil agent is low, it is necessary to apply a large amount of finish to the fiber in order to attach a preferable amount of the oil agent to the fiber. If the concentration is less than 1% by weight, the amount of the finish is too large, and it is difficult to give the finish to the fiber. On the other hand, if the concentration exceeds 50% by weight, the viscosity of the finishing agent is high, and the amount of the finishing agent decreases when a certain amount of the oiling agent is to be adhered to the fibers. Become.
It is preferable that the oil agent is attached in an amount of 0.2 to 3 wt% based on the mass of the fiber. If the amount is less than 0.2 wt%, the effect of the oil agent is small, and the yarn may be broken due to static electricity, or the yarn may be broken or fuzzed due to friction. On the other hand, if it exceeds 3 wt%, the resistance during running of the fiber may be too large, or the oil agent may adhere to the rolls, the hot plate, the guides, etc. to stain them. The oil agent is preferably attached to the fiber in an amount of 0.25 to 2.5 wt%, more preferably 0.3 to 2 wt%, based on the weight of the fiber. Of course, a part of the oil agent may permeate into the fiber.

As a method of applying the finish, a method using a known oiling roll or a method using a guide nozzle described in, for example, JP-A-59-116404 can be used. In order to suppress the occurrence of yarn breakage and fluff due to friction, a method using a guide nozzle is preferable.
In the conveyor method, it is preferable that the undrawn yarn is wound by controlling the winding tension using two or more sets of take-up rolls such as a first take-up roll 10 and a second take-up roll 11 shown in FIG. As a result, since the undrawn yarn can have a good winding form, fluctuations in the tension for unwinding the undrawn yarn during stretching are reduced, and a uniform and high-quality fiber with less fluff and yarn breakage is obtained. It becomes easier. The winding tension of the undrawn yarn is preferably 0.04 to 0.3 cN / dtex, more preferably 0.05 to 0.2 cN / dtex, and particularly preferably 0.06 to 0.15 cN / dtex.

Next, a method of stretching an undrawn yarn will be described.
The second important point for producing the fiber of the present invention is to draw the above-mentioned unoriented yarn having a low degree of orientation at an appropriate range of magnification. For this purpose, it is necessary to perform stretching at a stretching ratio of 30 to 99% of the maximum stretching ratio. Here, the maximum draw ratio refers to the highest draw ratio at which the draw ratio is increased and the fiber is not broken when drawing is performed under the same drawing equipment and conditions as those for actually producing the fiber. If the stretching ratio exceeds 99% of the maximum stretching ratio, thread breakage occurs, making it difficult to perform stable stretching. If the stretching ratio is less than 30% of the maximum stretching ratio, it is difficult to stretch uniformly, and fibers having large unevenness in thickness tend to be formed. The stretching ratio is preferably from 50 to 95% of the maximum stretching ratio, more preferably from 60 to 90%.
The temperature at which such stretching is performed is preferably 30 to 90 ° C. Here, the temperature at which the drawing is performed is a temperature at which the fiber is heated before drawing, and corresponds to the temperature of the first drawing roll in the conveyor method (FIG. 4) and the temperature of the first roll in the SDTU method (FIG. 5). By setting the temperature within this range, it is easy to perform high-magnification stretching while suppressing the occurrence of yarn breakage and fluff during stretching, and it is easy to obtain a fiber having a high breaking energy, which is the object of the present invention. The stretching temperature is more preferably 45 to 80 ° C, particularly preferably 55 to 75 ° C.
The drawn fiber is preferably subjected to a heat treatment in order to crystallize, reduce the shrinkage, and increase the strength. The heat treatment is preferably performed after the stretching to simplify the process.

The heat treatment temperature is preferably 50 to 200 ° C., and the heat treatment time is preferably 0.001 to 1 second. When the temperature is less than 50 ° C. or the time is less than 0.001 second, it is difficult to sufficiently crystallize the fiber and fix the structure. It tends to be. On the other hand, when the temperature exceeds 200 ° C., yarn breakage or fluff occurs, and it tends to be difficult to continuously draw the fiber. The temperature of the heat treatment is preferably from 60 to 180C, more preferably from 80 to 160C.
The heat treatment time may be long, but when the fiber is continuously drawn and heat-treated, it is preferably 1 second or less in view of productivity and the size of equipment. Since the crystallinity is determined by the heat treatment temperature and the heat treatment time, it is more preferable to select the heat treatment temperature and the heat treatment time according to the stretching speed.
When producing the fiber by the conveyor method, the drawing can be performed by using a draw-twisting machine, a roll stretching machine or the like which is usually used when producing PET or nylon fiber by the conveyor method.

An example of a method of drawing an undrawn yarn by the conveyor method will be described with reference to FIG.
The undrawn yarn 13 obtained by the conveyor method was drawn between the first drawing roll and the second drawing roll heated to the above-mentioned drawing temperature, and was heat-treated by the hot plate 15 heated to the above-mentioned heat treatment temperature. Thereafter, it is wound up by the winder 17. A drawing pin for fixing the drawing point, a device for entanglement of the fibers, and rolls and guides for deflecting the fibers may be provided on the way. In addition, it is also preferable to twist at the same time as winding.

Next, an example of a method for producing a fiber by the SDTU method will be described with reference to FIG.
The undrawn yarn taken up by the first roll 18 heated to the above-mentioned drawing temperature is then wound around the second roll 19 heated to the above-mentioned heat treatment temperature, and the first roll 18 and the first roll 18 After being stretched between the second roll 19 at an increased speed, heat treatment is performed with the second roll, and the roll is wound using a winder 21 that is lower in speed than the second roll. Here, reference numeral 20 denotes a non-self-driving free roll.
It is important that the speed of the first roll 18 be in the range of the undrawn yarn drawing speed described above. The speed of the second roll 19 is determined by the stretching ratio, and is usually 600 to 6000 m / min.
The drawn and heat-treated fiber is wound up using a winder 21.
The winding speed is determined by the stretching ratio and the relaxing ratio, but is usually 600 to 6000 m / min.

  In the SDTU method, it is preferable that the speed of the winder 21 be lower than that of the second roll 19. When the CD-PTT fiber of the present invention is manufactured with the speed of the winder 21 being the same as the speed of the second roll 19, the wound fiber shrinks, and the shrinkage force tightens the yarn tube. Even with a small winding amount of 1 kg or less, a phenomenon that the cheese-like package cannot be removed from the spindle of the winder or a bulge ratio of 20% or more, that is, so-called tight tightening may occur. As a result, good fibers cannot be obtained, or the unwinding tension from the package is high and greatly fluctuates, so that it is difficult to stably perform post-processing. On the other hand, when the speed of the winder is lower than that of the second roll, it is possible to suppress the tightening of the obtained package.

  The relaxation ratio (winding machine speed / second roll speed) is preferably 0.8 to 0.999, more preferably 0.83 to 0.99, and still more preferably 0.85 to 0.95. However, even if such a relaxation ratio is applied, if the winding amount is more than 2 kg, the winding may be tightened. In this case, by using a high-strength thread tube made of resin, metal, or thick paper to prevent deformation of the thread tube due to tight tightening, the thread tube can be easily removed from the spindle of the winder. Winding with a small winding amount of, for example, 2 kg or less is also an effective method of suppressing tightening. In order to suppress the tightening, it is preferable to cool the fiber to 20 ° C. (the glass transition point of the polymer) or less before winding. CD-PTT is easy to move even at a relatively low temperature because the molecule has a bent structure, for example, and is easily contracted by heat even during winding, as compared with PET, for example.

  Therefore, by performing such cooling, it becomes possible to suppress the molecular motion, and as a result, it is possible to suppress the tightening of the winding. Although the lower the yarn temperature after cooling, the better, it is usually 10 to 70C, preferably 0 to 50C. As a method for cooling the yarn, a method such as blowing cold air, immersing in a cooling liquid such as water or an organic solvent, or sliding on a low-temperature plate or roll can be used. Is most preferably provided between the second roll 19 and the winder 21. By such a method, it is possible to set the winding amount to 2 kg or more, preferably 5 kg or more. The tension between the second roll 19 and the winder 21 is preferably 0.02 to 0.20 cN / dtex. It is preferable to adjust the speed of the winder so that the tension is in this range.

In the conventional spinning of PET or nylon, when winding at such a low tension, the running of the yarn is not stable, and the yarn may come off from the traverse of the winding machine, and the yarn may break. When the winding yarn is automatically switched to the next yarn tube, a switching error may occur. However, surprisingly, in the case of the CD-PTT fiber, such a problem does not occur even when the fiber is wound at an extremely low tension as in the present invention. It is easy to obtain a rolled cheese-like package. It is considered that the reason why the winding can be performed stably even at such a low tension is due to the low elastic modulus and the high elastic recovery characteristic of the PTT fiber.
If the tension is less than 0.02 cN / dtex, the tension is too weak to achieve good traverse with the traverse guide of the winding machine, resulting in a poor winding form, a detachment of the yarn from the traverse, and a breakage of the yarn. Easy to happen. On the other hand, if it exceeds 0.20 cN / dtex, even if the fiber is cooled and wound up, it becomes easy to cause tightness. The tension at the time of winding is preferably from 0.025 to 0.15 cN / dtex, and more preferably from 0.03 to 0.10 cN / dtex.
In the present invention, entanglement treatment may be performed as needed in the spinning process. The entanglement treatment may be performed before or after applying the finish, before winding, or at a plurality of places.

  The winder 21 used in the present invention may be any winder such as a spindle drive system, a touch roll drive system, or a system in which both the spindle and the touch roll are driven. A driven winder is preferable for winding a large amount of yarn. In the case of a winder in which only one of the touch roll and the spindle is driven, the other is rotated by friction from the drive shaft, so the surface speed differs due to slippage between the thread tube attached to the spindle and the touch roll. I will. For this reason, when the thread is wound from the touch roll to the spindle, the thread is stretched or loosened, the tension is changed and the wound appearance is deteriorated, or the thread is easily rubbed and damaged. By driving both the spindle and the touch roll, it is possible to control the difference between the surface speeds of the touch roll and the thread tube, reduce slippage, and improve the yarn quality and winding appearance. it can.

It is preferable that the helix angle at the time of winding the fiber is 3.5 to 8 °. If the angle is less than 3.5 °, the yarns do not intersect with each other so much that the yarns are slippery and tend to cause twill drop and bulge. On the other hand, when the angle exceeds 8 °, the amount of yarn wound around the end of the yarn tube increases, so that the diameter of the end is larger than that of the center. For this reason, when winding, only the end comes into contact with the touch roll and the quality of the yarn is degraded, and the tension fluctuation when unwinding the wound yarn is increased, and the fluff or the yarn is removed. It is easy to cut frequently. The helix angle is more preferably 4 to 7 °, and particularly preferably 5 to 6.5 °.
The CD-PTT fiber obtained as described above can also be used as a short fiber. When short fibers are used, the fiber length is preferably 3 to 300 mm and the degree of crimp is preferably 5% or more. By using such short fibers, it can be suitably used in the field of materials such as inner materials made of spun yarn, materials for clothing such as sports, wadding, and nonwoven fabrics. If the fiber length is less than 3 mm or the degree of crimp is less than 5%, it becomes difficult to entangle the fibers, and if it exceeds 300 mm, the processability such as a spinning process is deteriorated. The fiber length is more preferably from 5 to 200 mm, even more preferably from 10 to 150 mm. The degree of crimp is more preferably from 8 to 35%.

Further, such a short fiber preferably has an elastic recovery rate at 10% elongation of 80% or more, more preferably 90% or more. If the elastic recovery is less than 80%, the stretchability tends to be poor. Further, the short fiber preferably has a flexural recovery of 80% or more, more preferably 90% or more. If the flexural recovery rate is less than 80%, when used for wadding and the like, there is a tendency that the material lacks resilience and is easily sagged.
Such short fibers, the long fibers obtained in the present invention, stuffer box crimping, steam jet or other thermal fluid crimping, crimping using a method such as gear crimping and then cutting. Obtainable. Although the fiber may be crimped without preliminary conditioning, it is preferable to crimp the fiber after heat treatment in order to increase the elastic recovery rate and the bending recovery rate. The heat treatment is preferably performed under constant length or under tension. Further, the heat treatment temperature is preferably 100 to 160 ° C., and the heat treatment time is preferably 0.01 to 90 minutes.

The CD-PTT fiber or staple fiber obtained as described above becomes a fiber product excellent in softness, stretchability, and color development by being used alone or as a part of a fabric.
In the present invention, the fiber product is not particularly limited as long as it is a product using the CD-PTT fiber or the short fiber of the present invention, and is used for clothing such as outerwear, innerwear, lining, sports, etc. For materials such as yarn, interlining, flocky, back, car seat, and synthetic leather. The mixing ratio of the CD-PTT fiber or the short fiber of the present invention in the fiber product is not particularly limited and can be arbitrarily set according to the purpose, but is usually 1 to 100%, preferably 5 to 100%. In particular, the fibers or staple fibers of the present invention have high toughness and a small shrinkage ratio. A fabric that does not shrink and can maintain a very soft texture and has excellent burst strength and tear strength can be obtained.

When other fibers are used for a part of the fabric, the other fibers are not particularly limited, but may be mixed with fibers such as stretch fibers typified by polyurethane elastic yarn, cellulose fibers, wool, silk, and acetate. Thereby, characteristics that cannot be obtained with a fabric using nylon fibers or PET fibers can be exhibited. That is, for example, the fabric can be dyed at normal pressure by using a cationic dye and / or a disperse dye, and has a unique texture with softness and stretchability that has not been achieved in the past.
The form and knitting and weaving method of the fiber product of the present invention are not particularly limited, and known methods can be used. For example, plain fabrics using the fibers or short fibers of the present invention for warp or weft, fabrics such as reversible fabrics, warp knits, wefts, knits such as circular knits, etc. May be applied.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples and the like.
In addition, the measuring method, the evaluation method, etc. are as follows.
(1) Intrinsic viscosity [η]
The limiting viscosity (dl / g) is obtained by extrapolating the specific viscosity ηsp and the ratio ηsp / C of the concentration C (g / 100 ml) to zero using an Ostwald viscometer at 35 ° C. and o-chlorophenol. Was determined according to the following equation.
[Η] = lim (ηsp / C)
C → 0
(2) Copolymerization ratio of BPE 2 g of the finely powdered polymer was precisely weighed, added to 25 ml of a 2N methanol solution of potassium hydroxide, and subjected to solvolysis under reflux for 4 hours. It quantified by gas chromatography using the obtained decomposition product.
The column was measured using a DURABONDDB-WAX 0.25 mm × 30 m (0.25 μm) at a heating rate of 20 ° C./min from 150 to 230 ° C. while flowing helium at 100 ml / min.

(3) Melting point The melting point was measured using a Pyris1 DSC (input compensation type differential scanning calorimeter) manufactured by PerkinElmer. Once the temperature was raised from room temperature to 280 ° C. at 100 ° C./min, left for 2 minutes, lowered to 0 ° C. at 500 ° C./min, left for 1 minute, and then raised to 280 ° C. at 20 ° C./min. It was measured. In the measurement of the melting point, the reason why the melting point is measured after cooling once after melting is to cancel the heat history of the polymer once when the polymer is taken out after the polymerization.
The melting point was the peak value of the melting peak. The peak value was determined using attached analysis software in order to avoid variation by the operator.
(4) Terminal Carboxyl Group Content To 1 g of the polymer (resin) was added 25 ml of benzyl alcohol, and the mixture was heated at 200 ° C. for 15 minutes under a nitrogen atmosphere. Thereafter, 3 drops of a phenolphthalein indicator and 25 ml of chloroform were added, and the mixture was titrated with a 0.02N solution of potassium hydroxide in benzyl alcohol to determine the amount of terminal carboxyl groups (meq / kg resin).

(5) Hue of polymer (L value, b ^* value)
The hue of the polymer was measured using a color computer of Suga Test Instruments Co., Ltd. The L value indicates the brightness of the polymer, and the b ^* value indicates the degree of yellow. In any case, the higher the numerical value, the greater the degree.
(6) Melt Stability 1 g of the obtained polymer was placed in a 30 ml glass sealed tube and vacuum-dried at 130 ° C. for 24 hours. After drying, the mouth of the sealed tube was melted while keeping the inside vacuum, so that air did not enter from the outside. The sealed tube containing the resin was kept in an oil bath at 270 ° C. for 2 hours. After melting, the polymer was taken out of the sealed tube, and the ratio of the intrinsic viscosity after melting to the intrinsic viscosity before melting was defined as the melt stability.

(7) Esterification reaction rate In the esterification reaction, the reaction rate of terephthalic acid was defined as the esterification reaction rate. In this case, the reaction of terephthalic acid follows the following formula. When all the carboxyl groups in one mole of terephthalic acid react, two moles of water are generated. When 2 mol of water was generated, the esterification reaction rate was defined as 100%, and the esterification reaction rate was determined from the amount of water generated during the esterification reaction.
HOOCφCOOH + HOCH ₂ CH ₂ CH ₂ OH
→ terephthalic acid ester + 2H ₂ O
In the formula, φ represents a phenylene group.
(8) Peak temperature of dynamic loss tangent (Tmax)
The dynamic loss tangent (tan δ) and the dynamic elastic modulus at each temperature were measured at a measurement frequency of 110 Hz and a heating rate of 5 ° C./min in dry air using Leo Vibron manufactured by Orientec. From the results, a dynamic loss tangent-temperature curve was determined, and Tmax (° C.), which is the peak temperature of the dynamic loss tangent, was determined on this curve.

(9) Boiling water shrinkage (BWS)
Based on JIS-L-1013, it was determined as a skein contraction rate.
(10) Strength (rupture strength), elongation (elongation at break), toughness 20 cm between grips using Tensilon manufactured by Orientec Co., Ltd., which is a constant speed elongation type tensile tester based on JIS-L-1013. And a tensile speed of 20 cm / min.
The toughness was calculated from the following equation using the strength and elongation measured by the above methods.
Toughness = [strength (cN / dtex)] x [elongation (%)] ^1/2
(11) Elastic recovery rate The elastic recovery was determined as an elastic recovery rate obtained by the following method.
The fiber is attached to a tensile tester with a distance between chucks of 20 cm (L0), stretched to a predetermined stretching rate at a stretching speed of 20 cm / min, and left for 1 minute. Thereafter, the material is contracted again at the same speed, and a stress-strain curve is drawn. During the contraction, the elongation when the stress becomes zero is defined as the residual elongation (La). The elastic recovery was determined according to the following equation.
Elastic recovery rate (%) = [(L0−La) / L0] × 100

(12) Birefringence Refraction of polarized light observed on the surface of a fiber using an optical microscope and a compensator according to Fiber Handbook (raw material edition), page 969 (5th printing, issued by Maruzen Co., Ltd., 1978). Determined from the date.
(13) Density Based on JIS-L-1013, the density was measured by a density gradient tube method using a density gradient tube made of carbon tetrachloride and n-heptane.
(14) U%
It was obtained by measuring under the following conditions using USTER TESTER 3 manufactured by Zellbeger Worcester Co., Ltd.
Measurement speed: 100m / min Measurement time: 1 minute Number of measurements: twice Twist type: S twist

(15) Color of fiber The evaluation was carried out using an evaluation fabric prepared by the following method. The WI value, which is whiteness, was measured by a method based on ASTM-E313-73, and the YI value, which was yellowness, was measured by a method based on ASTM-D1925-70 under the following conditions.
[Method of making evaluation cloth]
1) Use the sample as a single-knit fabric.
2) Scouring is performed in warm water of 70 ° C. containing 2 g / l of score roll FC-250 for 20 minutes.
3) Perform heat setting at 180 ° C. for 30 seconds using a tenter.
〔Measuring method〕
Apparatus: spectrophotometer: Macbeth CE-3000 (manufactured by Macbeth)
Measurement conditions: Measurement was carried out according to the following method in accordance with ASTM-D1925-70 (YI value) and ASTM-E313-73 (WI value).
Field of view: 2 °
Light source: C (CIE-1964)
Specular gloss: Included UV light: Included The calculation was performed according to the following formula, and the YI value and WI value were calculated.
YI = 100 × (1.28X−1.06Z) / Y
WI = 4 × 0.847Z-3Y
Here, X, Y, and Z are tristimulus values in the XYZ color system of the sample.

(16) Bulge ratio The winding width Q of the innermost layer of the yarn layer (104) shown in FIG. 2A or FIG. 2B and the winding width R of the bulging portion are measured, and the following formula is obtained. It calculated according to.
Bulge rate (%) = {(RQ) / Q} × 100
(17) Crystallization peak temperature of undrawn yarn Measured under the following conditions using Pyris1 DSC (input compensation type differential calorimeter) manufactured by PerkinElmer, and the peak value of the exothermic peak due to crystallization was determined as the crystallization peak temperature. And The peak value was determined using the attached analysis software.
Measurement temperature: 0 to 280 ° C
Heating rate: 20 ° C./min (18) Adhesion rate of oil agent Based on JIS-L-1013, the fiber was washed with diethyl ether, and diethyl ether was distilled off. The ratio obtained by dividing was defined as the oil agent adhesion rate.

(19) Degree of crimp The length of the sample when an initial load of 0.01764 cN / dtex (0.02 mg / denier) is applied, and the length when a load of 0.265 cN / dtex (0.3 mg / denier) is applied Was determined according to the following equation, where b is the length. The test was performed 10 times, and the average value was used as the value of the degree of crimp.
Crimping degree (%) = [(ba) / b] × 100
(20) Bending recovery rate The fibers before cutting are not overlapped with each other in a state where an initial load of 0.0294 cN / dtex (1/30 mg / denier) is applied to a plate having a width of 30 mm, a length of 40 mm, and a thickness of 40 μm. 5 times, and apply a load of 1 kg to the bent portion of the fiber. After 30 seconds, the load was removed, the fiber was cut at the center of the plate, the recovery angle after 10 minutes was measured, and the recovery rate was calculated.

[Example 1]
1300 g (6.7 mol) of dimethyl terephthalate, 1144 g (15 mol) of 1,3-propanediol, 40.5 g (0.14 mol) of dimethyl 5-sodium sulfoisophthalate, 2.4 g of calcium acetate monohydrate ( 0.014 mol) and 1.0 g (0.01 mol) of lithium acetate dihydrate were placed in a 3 liter autoclave, and transesterification was carried out at 220 ° C. while distilling off methanol. The transesterification rate was 95%. After completion of the transesterification reaction, 0.65 g of trimethyl phosphate and 1.34 g of titanium tetrabutoxide are added, and after stirring for 30 minutes, while distilling off 1,3-propanediol, at a degree of vacuum of 13.3 to 66.5 Pa. A polycondensation reaction was performed at 270 ° C. for 1.5 hours. After the completion of the polycondensation reaction, the obtained melt was put into water in the form of a rope, and the obtained rope was cut finely to obtain a chip-shaped prepolymer. At the end of the polycondensation reaction, the melt viscosity still showed a tendency to increase over time.

The intrinsic viscosity of the prepolymer was 0.54 dl / g, and the amount of terminal carboxyl groups was 16 meq / kg resin. The obtained prepolymer was subjected to solid-state polymerization at 215 ° C. under a nitrogen stream. The solid-state polymerization rate of the prepolymer was high, and the obtained CD-PTT was excellent in melt stability and exhibited excellent hue (Table 1).
After drying the obtained polymer chip to a moisture content of 30%, it was melted at 265 ° C. by an extruder and sent to a spin head at 285 ° C., and a circular hole having a diameter of 0.35 mm and a length of 0.35 mm was formed into 36. It was extruded through an open spout. A heating cylinder heated to 250 ° C. and having a length of 100 mm was provided under the spinneret. The spinning surface temperature at this time was 271 ° C. An undrawn yarn was prepared by spinning at a spinning speed of 800 m / min. Next, the obtained undrawn yarn is stretched at a drawing speed of 600 m / min at a hot roll of 60 ° C. and a hot plate of 140 ° C. so that the elongation becomes 40%, 56 dtex / 36 f, intrinsic viscosity 0.86. A drawn yarn having a strength of 2.8 cN / dtex, an elongation of 40%, an elasticity of 2.0 cN / dtex, a Tmax of 116 ° C. and a BWS of 13.1% was obtained.

The obtained fiber was made into a single-knit fabric and dyed using a cationic dye. Kayacryl Black BS-ED (manufactured by Nippon Kayaku Co., Ltd., 8% omf, bath ratio 1:50) is used as a cationic dye, and 1 g / liter of Disper TL (manufactured by Meisei Chemical Co., Ltd.) is used as a dispersant. used. A dye was added to an aqueous solution whose pH was adjusted to 4 using 3 g / liter of sodium sulfate, acetic acid and sodium acetate, to obtain a dye solution. After dyeing at 120 ° C. for 1 hour, the resultant was subjected to soaping at 70 ° C. for 15 minutes at 1 g / liter of Senkanol A-900 (manufactured by Senka Co., Ltd.) at a bath ratio of 1:50. The exhaustion of the dye was 85%, and the obtained dyed product was dyed dark.
The light resistance test was conducted at 63 ° C. for 30 hours using a fade meter, but there was almost no fading.

[Example 2]
A prepolymer was obtained in the same manner as in Example 1 except that the polycondensation reaction was performed at 260 ° C. for 1.5 hours. The intrinsic viscosity of the prepolymer was 0.52 dl / g, and the amount of terminal carboxyl groups was 16 meq / kg resin. The obtained prepolymer was subjected to solid-state polymerization at 215 ° C. under a nitrogen stream. The solid-state polymerization rate of the prepolymer was high, and the obtained CD-PTT was excellent in melt stability and exhibited excellent hue (Table 1).
[Comparative Example 1]
A prepolymer was obtained in the same manner as in Example 1 except that the polycondensation reaction was performed at 290 ° C. for 2 hours. The intrinsic viscosity of the prepolymer was 0.58 dl / g, and the amount of terminal carboxyl groups was 45 meq / kg resin. The obtained prepolymer was subjected to solid-state polymerization at 215 ° C. under a nitrogen stream. The solid-state polymerization rate of the prepolymer was slower than that of the prepolymer of Example 1, and the obtained CD-PTT had reduced melt stability and hue (Table 1).

[Comparative Example 2]
A polymerization experiment was performed in the same manner as in Example 1 except that the polycondensation reaction was performed for 2.5 hours. From the stage where the polycondensation reaction has elapsed for about 2 hours to the end of the polycondensation reaction, the melt viscosity has not been increased. It is considered that the growth of the molecular chain by the polycondensation reaction and the depolymerization by the thermal decomposition were almost in an equilibrium state.
The intrinsic viscosity of the prepolymer was 0.60 dl / g, and the amount of terminal carboxyl groups was 43 meq / kg resin. The obtained prepolymer was subjected to solid-state polymerization at 215 ° C. under a nitrogen stream. The solid-state polymerization rate of the prepolymer was lower than that of the prepolymer in Example 1, and the obtained CD-PTT had reduced melt stability and hue (Table 1).

[Comparative Example 3]
In Example 1, homoPTT having an intrinsic viscosity of 0.92 was obtained in the same manner as in Example 1 except that dimethyl 5-sodium sulfoisophthalate was not used. Regarding the physical properties of the obtained CD-PTT, as shown in Table 1, the amounts of SIPM and BPE were out of the range of the present invention.
Further, the hue, particularly the b ^* value, was poor. Although the reason is not necessarily clear, it is considered that dimethyl 5-sodium sulfoisophthalate was not used. Therefore, it is considered that the ester-forming sulfonate has an effect of increasing the whiteness of the polymer.
A dyeing experiment with a cationic dye was conducted in the same manner as in Example 1, but the exhaustion rate was 8%. It was found that the dye could not be dyed with the cationic dye unless the ester-forming sulfonate was copolymerized (Table 1).
[Example 3]
The procedure was performed in the same manner as in Example 1 except that the number of moles of dimethyl 5-sodium sulfoisophthalate was changed to 2.5 mol%. The obtained polymer was excellent in melt stability and exhibited excellent hue (Table 1).

[Comparative Example 4]
A transesterification reaction was performed using dimethyl terephthalate and ethylene glycol (molar ratio 1: 1.6) and manganese acetate (0.05 wt% of dimethyl terephthalate) as a catalyst. To 0.98 mol of the obtained bis (hydroxyethyl) terephthalate, 0.02 mol of dimethyl 5-sodium sulfoisophthalate, 200 mg of lithium acetate dihydrate, and 125 mg of antimony trioxide as a catalyst (in this case, titanium tetrabutoxide was used. When used, the polymer is severely colored.), And 130 mg of trimethyl phosphate was added as a heat stabilizer, and melt polymerization was performed at 290 ° C. under a vacuum of 13.3 to 66.5 Pa. The intrinsic viscosity of the obtained copolymerized PET was 0.50 dl / g, the melting point was 256 ° C., the amount of terminal carboxyl groups was 45 meq / kg resin, and the b ^* value was 7.8.
After drying the thus obtained copolymerized PET, it was extruded through 24 pores of 0.23 mm through a 20 μm sintered filter at a discharge rate of 25 g / min from the spinning pack. It increased by about 1.96 × 10 ⁴ kPa from the start of spinning.
On the other hand, when the same experiment was performed using the CD-PTT of Example 1, the pressure in the pack increased only about 2.94 × 10 ³ kPa from the start of spinning in one week.
When dimethyl 5-sodium sulfoisophthalate is copolymerized with polyethylene terephthalate, a large amount of aggregates (complexes of manganese, 5-sodium sulfoisophthalic acid and a phosphorus compound) that are modified and infused with a sulfonate are produced. It can be seen that the CD-PTT of the invention produces a small amount of such aggregates.

[Reference Example 1]
1300 g (7.8 mol) of terephthalic acid, 911 g (12.0 mol) of 1,3-propanediol, 1.35 g of titanium tetraisopropoxide, and 0.13 g of cobalt acetate tetrahydrate were charged into a 3 liter autoclave, The esterification reaction was carried out at 250 ° C. using a rectification column while distilling off water. The esterification reaction rate was 98%. The esterification reaction rate was calculated from the amount of water distilled off.
After the esterification was completed (esterification reaction rate: 98%), 47.3 g (0.16 mol) of dimethyl 5-sodium sulfoisophthalate and 1.09 g (0.01 mol) of lithium acetate dihydrate were added. At this time, dimethyl 5-sodium sulfoisophthalate and lithium acetate dihydrate were added as a 15% solution of 1,3-propanediol. The molar ratio of 1,3-propanediol to terephthalic acid (hereinafter abbreviated as G value) was 1.5. The number of moles of the sulfonic acid salt corresponds to 2.0 mole% of the total number of moles of carboxylic acid.

Next, 0.65 g of trimethyl phosphate was added, and a polycondensation reaction was performed at a vacuum degree of 13.3 to 66.5 Pa for 3 hours while distilling off 1,3-propanediol. After the completion of the polycondensation reaction, the obtained melt was put into water in the form of a rope, and the obtained rope was cut finely to obtain a chip-shaped polymer. The obtained polymer was excellent in melt stability and exhibited excellent hue (Table 2).
Using the obtained polymer, spinning was performed under the conditions shown in Table 3. The obtained fiber (56 dtex / 36f) had a strength of 2.5 cN / dtex, an elongation of 35%, an elasticity of 22 cN / dtex, a Tmax of 117 ° C., and a BWS of 13.3%.
The obtained fiber was made into a single-knit fabric, and dyed with a cationic dye in the same manner as in Example 1. The exhaustion rate of the dye was 75%, and the obtained dyed product was dyed dark. The light resistance test was conducted at 63 ° C. for 30 hours using a fade meter, but there was almost no fading.
In addition, a test for pressure rise in the pack was performed using this CD-PTT in the same manner as in Comparative Example 4, and the pressure in the pack increased only about 2.94 × 10 ³ kPa from the start of spinning in one week. Did not. When dimethyl 5-sodium sulfoisophthalate is copolymerized with polyethylene terephthalate, a large amount of aggregates in which the sulfonate is modified and made infusible are formed. Is small.

[Reference Example 2]
The procedure was performed in the same manner as in Reference Example 1 except that the G value was changed. The obtained polymer was excellent in melt stability and exhibited excellent hue (Table 2).
[Comparative Example 5]
This was carried out in the same manner as in Reference Example 1 except that dimethyl 5-sodium sulfoisophthalate was charged into an autoclave together with terephthalic acid before the esterification reaction, that is, before the polymerization was started. The melting point of the obtained polymer was greatly reduced, and the melt stability and the hue were reduced (Table 2).
Even when the polymerization time was further extended, the intrinsic viscosity did not increase to 0.6 dl / g or more. In contrast, the polymer of Reference Example 1 reached a maximum intrinsic viscosity of 0.8 dl / g when the polymerization time was extended.
[Comparative Example 6]
The procedure was performed in the same manner as in Reference Example 1 except that the G value was set to 3.0. The obtained polymer had a lower melting point, lower melt stability and lower hue (Table 2).

[Comparative Example 7]
The procedure was performed in the same manner as in Reference Example 1, except that dimethyl 5-sodium sulfoisophthalate was added when the esterification reaction rate was 60%. The obtained polymer had a lower melting point, lower melt stability and lower hue (Table 2).
[Comparative Example 8]
The procedure was performed in the same manner as in Reference Example 1, except that dimethyl 5-sodium sulfoisophthalate was not added. Although the obtained polymer had a high degree of polymerization and a high melt viscosity, it could not substantially be dyed with a cationic dye, and had a high b ^* value (high yellowness) (Table 2).
[Example 4]
The CD-PTT obtained in Reference Example 2 was subjected to solid-state polymerization at 215 ° C. under a nitrogen atmosphere. The obtained polymer was excellent in melt stability and exhibited excellent hue (Table 2).
[Reference Example 3]
In Reference Example 1, the procedure was performed in the same manner as in Reference Example 1, except that dimethyl 5-sodium sulfoisophthalate and lithium acetate dihydrate were not dissolved in 1,3-propanediol and were added as they were as solids. The obtained polymer was excellent in melt stability and exhibited excellent hue (Table 2).

[Examples 5 to 8]
1300 g (6.7 mol) of dimethyl terephthalate, 1144 g (15 mol) of 1,3-propanediol, 40.5 g (0.14 mol) of dimethyl 5-sodium sulfoisophthalate, 2.4 g of calcium acetate monohydrate ( 0.014 mol) and 1.0 g (0.01 mol) of lithium acetate dihydrate were placed in a 3 liter autoclave, and transesterification was carried out at 220 ° C. while distilling off methanol. Next, after adding 0.65 g of trimethyl phosphate, 1.34 g of titanium tetrabutoxide and 0.05 wt% of the theoretical polymer amount, 13.3 to 66.5 Pa while distilling off 1,3-propanediol. The polycondensation reaction was performed at 270 ° C. for 2 hours at a degree of vacuum.
The obtained prepolymer (terminal carboxyl group content was 19 meq / kg resin) was further subjected to solid-state polymerization at 210 ° C. under a nitrogen stream to obtain a polymer having an intrinsic viscosity shown in Table 3. In each of the obtained polymer chips, b ^* was in the range of −3 to 5, and the L value was 85 or more, and the whiteness was excellent.
After drying the obtained polymer chip to a water content of 50%, it was melted at 265 ° C. by an extruder and sent to a spin head at 285 ° C., and a circular hole having a diameter of 0.35 mm and a length of 0.35 mm was formed into 36. It was extruded through an open spout. A 100 mm heating tube heated to 250 ° C. was installed under the spinneret. Table 3 shows the temperature of the heating cylinder, the surface temperature of the spinneret, and the spinning draft used.

Next, the extruded molten filament is cooled and solidified by applying cold air at a temperature of 20 ° C. and an air velocity of 0.4 m / min. Then, using a guide nozzle, octyl stearylate 60 wt%, polyoxyethylene alkyl ether 15 wt%, phosphorus An oil agent containing 3 wt% of potassium acid was applied as a water emulsion finish having a concentration of 20 wt% so that the oil agent adhesion rate to the fiber was 1.0 wt%.
The fiber to which the oil agent was applied passed through the first take-up roll at the take-up speed shown in Table 3, and then passed through the second take-up roll so that the tension became 0.1 cN / dtex. To obtain an undrawn yarn. The physical properties of the wound undrawn yarn are shown in Table 3. Each of the undrawn yarns had the elongation and crystallization peak temperature in the preferred ranges shown in the present invention.
The undrawn yarn thus wound was drawn at a draw ratio shown in Table 3 with the first drawing roll at 60 ° C. and the hot plate at 140 ° C. by a drawing machine shown in FIG. 4 to obtain a fiber of 56 dtex / 24 filament. Got.
Table 5 shows the physical properties of the obtained fiber. In each case, no fluff was generated during spinning and stretching. In addition, all the fibers corresponded to the scope of the present invention, and were fibers having a low shrinkage and a high toughness.

[Comparative Examples 9 to 11] (Conveying method)
Fibers were produced in the same manner as in Example 5 using various CD-PTTs. Table 5 shows the physical properties of the obtained fiber.
In Comparative Example 9, since the degree of polymerization of the polymer used was low, the degree of polymerization of the obtained fiber was low, the toughness was low, and the BWS was large.
In Comparative Example 10, the spun surface temperature was reduced due to the absence of the heating tube, and thus the obtained undrawn yarn had a low crystallization peak temperature. The obtained undrawn yarn was drawn, but had a Tmax of less than 105 ° C. and a BWS of more than 16%, out of the range of the present invention. Further, the toughness of the fiber was low, and the fiber was not satisfactory.
In Comparative Example 11, both the elongation and the crystallization peak temperature of the undrawn yarn were low because the take-up speed was high. The obtained undrawn yarn was drawn, but had a Tmax of less than 105 ° C. and a BWS of more than 16%, out of the range of the present invention. Further, the fiber had low toughness.

[Examples 9 and 10] (SDTU method)
Using the polymer obtained in the same manner as in Example 5 (described in Table 4), spinning was performed using an SDTU spinning apparatus shown in FIG. Spinning was carried out in the same manner as in Example 5 except for the conditions shown in Table 4, and drying and finishing were applied. The fiber to which the finishing agent was applied was drawn, heat-treated, and wound under the conditions shown in Table 4 using a first roll, a second roll, and a winder set to the conditions shown in Table 4, and 86 dtex. / 24 filament fiber was obtained. Table 5 shows the obtained fiber properties.
In addition, in order to measure the physical properties of the undrawn yarn before stretching, the physical properties of the undrawn yarn directly wound at the same speed as the first roll were measured. Table 4 shows the results.
Regarding the physical properties of the undrawn yarn, the elongation and the crystallization peak temperature were in the preferable ranges in each case. In each case, the resulting fibers did not show any fluff during spinning, and the physical properties of the obtained fibers were also within the scope of the present invention. The fibers had low shrinkage and high toughness. .
In addition, the cheese-like package obtained by winding 4 kg of the fiber can be easily removed from the spindle of the winder, and the bulge ratio is within the scope of the present invention as shown in Table 5; Did not.

[Comparative Example 12] (SDTU method)
Spinning was performed in the same manner as in Example 9 except for the conditions shown in Table 4, to obtain fibers. Table 5 shows the physical properties of the obtained fiber.
In Comparative Example 12, since there was no heating tube, the obtained fiber had a Tmax of less than 105 ° C, which was out of the range of the present invention. Further, the fiber had low toughness. When 4 kg of the fiber was wound, the tightness of the winding was so high that the cheese-like package could not be removed from the spindle of the winder.
In addition, in order to measure the physical properties of the undrawn yarn before stretching, the physical properties of the undrawn yarn directly wound at the same speed as the first roll were measured. As shown in Table 4, the undrawn yarn had a crystallization peak temperature lower than the preferred range of the present invention.

[Example 11]
The fiber obtained in Example 5 was subjected to a constant-length moist heat treatment at 150 ° C. for 5 minutes, and then crimped by stuffer box crimping and cut to obtain short fibers. The obtained short fibers had a fiber length of 60 mm, a degree of crimp of 14%, and an elastic recovery of 95%. Further, the bending recovery rate of the crimped fiber before cutting was as good as 90%.
The obtained short fibers had good dyeing properties, had a soft texture, and could be made into spun yarn, wadding, and the like having excellent stretchability.

[Example 12]
A warp knitted fabric was knitted using the fiber obtained in Example 5 and 233 dtex Leica (polyurethane-based elastic fiber manufactured by Asahi Kasei Corporation). The knitting gauge was 28 G, the loop length was 1080 mm / 480 course for CD-PTT fiber, 112 mm / 480 course for stretch fiber, and the driving density was 90 course / 2.54 cm. The mixing ratio of the CD-PTT fiber was set to 75%.
The obtained dough was subjected to relaxing scouring at 90 ° C. for 2 minutes and subjected to dry heat setting at 160 ° C. for 1 minute. Next, 8% omf of Kayacryl Black BS-ED (a cationic dye manufactured by Nippon Kayaku Co., Ltd.) was used as a dye, and 1 g / liter of Disper TL (a nonionic activator manufactured by Meisei Chemical Co., Ltd.) was used as a dispersant. A dye was added to an aqueous solution adjusted to pH 4 using 3 g / liter of sodium sulfate, acetic acid and sodium acetate to form a dye liquor. The dye concentration was 8% omf, and the bath ratio was 1:50 at 105 ° C. for 1 hour. Staining was performed. After dyeing, finishing was performed by a conventional method.
The obtained dyed fabric was sufficiently dyed, and was also excellent in dyeing fastness. This dyed knitted fabric did not excessively shrink during dyeing, was very soft, had excellent stretchability, and exhibited an excellent texture with tension and waist.
The above Examples and Comparative Examples are shown in the table.

According to the present invention, it is possible to obtain a CD-PTT having a high molecular weight, which has a high melting point and, as a result, has a small decrease in viscosity upon melting and is suitable as a raw material for a CD-PTT fiber excellent in hue.
Further, the polymer of the present invention and the method for producing the same have excellent characteristics which could not be expected in the past.
The first excellent feature is that the CD-PTT of the present invention greatly improves the whiteness of the polymer as compared with the homo-PTT polymerized according to the same method. Although the reason for this is not clear, high whiteness is a very favorable effect from the viewpoint of further improving the color developability when processed into fibers. In particular, in the case of dyeing with a cationic dye requiring sharpness, the color developability can be enhanced by the high whiteness of the fiber.

  Second, the terminal carboxyl group content of cationic dye-dyeable polyethylene terephthalate having a structure similar to that of CD-PTT is usually larger than 40 meq / kg resin, whereas the PTT of the present invention has This means that the amount of terminal carboxyl groups is quite low. When the amount of terminal carboxyl groups is large, there is a problem that when the prepolymer is discharged from the polymerization vessel at the stage of completion of the melt polymerization, the whiteness and the intrinsic viscosity decrease with the time of dispensing, and the physical properties of the prepolymer greatly change. In addition, there is a problem that the fiber strength of the fiber during dyeing or processing is greatly reduced. On the other hand, such problems hardly occur in the CD-PTT and CD-PTT fibers obtained from the prepolymer in the present invention.

Third, the CD-PTT of the present invention has a small amount of infusible aggregates derived from ester-forming metal salts of sulfonic acids, catalysts, heat stabilizers and the like. When the amount of aggregates is small, the exchange cycle of the spinning pack becomes long, and long-term continuous spinning becomes possible, so that high productivity can be achieved. In addition, when the amount of aggregates is small, fluff and yarn breakage are reduced, and the spinning yield is increased. Cationic dye-dyeable polyethylene terephthalate having a similar structure contains a large amount of aggregates because the catalyst used is different, and the problem of aggregates has not yet been completely solved.
As described above, since the CD-PTT of the present invention has excellent performance, it is useful as a raw material for fibers, molded products, films, and the like. In particular, the CD-PTT fiber of the present invention can be dyed with a cationic dye, has high toughness, and has no excessive shrinkage due to dyeing, processing, and the like, so that fabric design is easy and can be applied to various clothing. In particular, it is particularly suitable for use in compounding urethane elastic yarn, polyester elastic yarn, and the like, and for processing urethane resin.
Specific examples of textile products that are used include clothing such as outerwear, innerwear, and sports, materials such as carpets, flocky, monofilament, and bags, and nonwoven fabrics such as spunbond, microweb, and spunlace.

It is a figure which shows a nonuniformity curve (mass change of fiber) when a fiber is passed through USTER TESTER3. In FIG. 1, M represents mass, t represents time, Xi represents an instantaneous value of mass, Xave represents an average value, T represents measurement time, and a represents an area (shaded area) between Xi and Xave. (A) is the schematic diagram which shows the state (desired shape) of the cheese-like package which wound the PTT fiber of this invention around the yarn tube. (B) is a schematic diagram showing a state (undesired shape) of a bulge-like cheese-like package. It is the schematic which shows typically an example (conveying method) of the manufacturing method of the CD-PTT fiber of this invention. It is the schematic which shows typically an example of the process of extending | stretching the undrawn yarn once wound up in an example (conveying method) of the manufacturing method of CD-PTT fiber of this invention. It is the schematic which shows typically another example (SDTU method) of the manufacturing method of CD-PTT fiber of this invention.

Explanation of reference numerals

1: Dryer 2: Extruder 3: Bend 4: Spin head 5: Spinner pack 6: Spinner 7: Heating tube 8: Cooling air 9: Finishing agent applying device 10: First take-up roll 11: Second take-up roll 12: Winding machine (package)
13: undrawn yarn 14: first drawn roll 15: hot plate 16: second drawn roll 17: winder 18: first roll 19: second roll 20: free roll 21: winder 21a: spindle 21b: Touch roll

Claims (10)

A copolymerized polytrimethylene terephthalate fiber satisfying the following (1) to (6).
(1) The ester-forming sulfonic acid salt is copolymerized in an amount of 0.5 to 5 mol% based on all dicarboxylic acid components.
(2) 0.1 to 2.5 wt% of bis (3-hydroxypropyl) ether is copolymerized.
(3) The intrinsic viscosity is 0.65 to 1.4 dl / g.
(4) The amount of terminal carboxyl groups is 5 to 40 meq / kg fiber or less.
(5) Toughness is 16 or more.
Here, toughness is a value calculated from the following equation.
Toughness = [strength (cN / dtex)] x [elongation (%)] ^1/2
(6) U% is 0 to 3%. The copolymerized polytrimethylene terephthalate fiber according to claim 1, wherein the following (7) and (8) are satisfied.
(7) The peak temperature of the dynamic loss tangent is 105 to 140 ° C.
(8) The boiling water shrinkage is 0 to 16%.   The copolymerized polytrimethylene terephthalate fiber according to claim 1 or 2, wherein the toughness is 17.5 or more. A copolymer polytrimethylene terephthalate satisfying the following (a) to (d) is extruded from a spinneret at a spinning surface temperature of 250 to 295 ° C and a spinning draft represented by the following formula becomes 50 to 1500, After being cooled and solidified, an undrawn yarn having a breaking elongation of 200 to 400% and a crystallization peak temperature of 64 to 80 ° C is taken at a speed of 100 to 3000 m / min, and the undrawn yarn is heated to 45 to 80 ° C. The copolymerized polytrimethylene according to any one of claims 1 to 3, wherein the film is stretched at a temperature of from 60 to 90% of the maximum stretching ratio and heat-treated at a temperature of from 100 to 160 ° C. A method for producing terephthalate fiber.
(A) 0.5 to 5 mol% of the ester-forming sulfonic acid salt is copolymerized with respect to all dicarboxylic acid components.
(B) 0.1 to 2.5 wt% of bis (3-hydroxypropyl) ether is copolymerized.
(C) The intrinsic viscosity is 0.65 to 1.5 dl / g.
(D) The amount of terminal carboxyl groups is not more than 25 meq / kg resin.
Spinning draft = (V2) / (V1)
V1: Linear velocity of polymer when extruded from spinneret (m / min)
V2: First roll speed (m / min) (take-up speed when the first roll is not used)   5. The copolymerized polytrimethylene terephthalate according to claim 4, wherein the copolymerized polytrimethylene terephthalate is extruded from a spout provided with a heating tube having a length of 50 to 300 mm and a temperature of 150 to 350 ° C. under the spout. Fiber manufacturing method.   6. The method for producing a copolymerized polytrimethylene terephthalate fiber according to claim 4, wherein the undrawn yarn is once wound and then drawn.   The method for producing a copolymerized polytrimethylene terephthalate fiber according to claim 4 or 5, wherein the drawn undrawn yarn is continuously drawn without being wound once.   A copolymerized polytrimethylene terephthalate short fiber obtained by crimping the copolymerized polytrimethylene terephthalate fiber according to claim 1 or 2, wherein the fiber length is 3 to 300 mm and the degree of crimp is 5 % Or less of copolymerized polytrimethylene terephthalate.   A fiber product using the copolymerized polytrimethylene terephthalate fiber according to claim 1 or 2 partially or entirely.   A fiber product in which the short fibers of the copolymerized polytrimethylene terephthalate according to claim 8 are partially or wholly used.

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