JP4886657B2 - Hygroscopic crimped composite fiber - Google Patents

Description

  The present invention has a self-regulatory function in which the crimp rate reversibly changes in the presence of moisture, and when water is absorbed, more crimps are expressed, so that the apparent length of the yarn shrinks and the texture of the woven or knitted structure becomes The present invention relates to a composite fiber that has a water-absorbing crimping performance of clogging and can be made into a fabric that can exhibit excellent crimp rate change characteristics even after dyeing and finishing processes.

  Clothing made from woven and knitted fabrics of natural fibers such as cotton and wool reversibly changes with humidity, so the knitted fabric's eyes open according to the surrounding humidity and air permeability is improved. , Has the characteristics of lowering the humidity of the air layer between clothing and between clothing, so-called breathable self-regulating function, and the fiber itself absorbs moisture such as sweat and absorbs and releases moisture ing. Therefore, when wearing clothing using such natural fibers, there is little feeling of discomfort due to changes in ambient humidity and sweat. Following such natural fibers, attempts have been made to impart a crimpable self-regulating function to hygroscopic synthetic fibers. For example, Patent Document 1 proposes a composite fiber that joins a modified polyester and polyamide side-by-side to impart a reversible shape change to a humidity change.

  Then, when wet by rain, etc., the objective is to obtain a composite fiber having a breathable self-regulating function that closes the eyes of the woven or knitted fabric by shrinking the crimp of the raw yarn and expresses moisture permeability and waterproofness Patent Documents 2 and 3 propose composite fibers in which the crimp rate is increased at the time of moisture absorption by improving the heat treatment conditions. However, the above prior art has a problem that the change in the crimping rate becomes small after a post-process such as dyeing or finishing, and a decrease in the crimping performance or a reverse phenomenon occurs when the temperature or load in the finishing process changes. There was a problem. Especially for fabrics such as knitted and knitted fabrics, there are variations in the load applied to the single yarns constituting the fabric in the dyeing and finishing processes, so that it is difficult to develop crimping performance uniformly throughout the fabric. The fact is that it has not reached a certain level.

JP 58-46119 A JP 58-46118 A Japanese Patent Laid-Open No. 61-19816

  The present invention has been made against the background of the above-described conventional technology. The purpose of the present invention is to cause crimps to occur when water is absorbed and the apparent yarn length to shrink, thereby clogging the eyes of the woven or knitted structure, providing a moisture-permeable and waterproof function, and see-through. An object of the present invention is to provide a raw yarn for a fabric having a prevention performance and a hygroscopic property and a method for producing the same. Moreover, it is an object of the present invention to provide a composite fiber that can stably maintain the above-described excellent crimp characteristics even after undergoing steps such as dyeing and finishing.

As a result of intensive studies to achieve the above object, the present inventors have completed the present invention.
That is, in a composite fiber in which a polyamide component and a polyester component are bonded side-by-side, at least 60 mol% of the units constituting the polyester are occupied by ethylene terephthalate units, and 0.5 to 40 mol% is ethylene isophthalate. It is set as the copolyester which a unit occupies, and it is set as the composite fiber which contains 5 to 30 weight% of water-swellable polyetherester polymers (A) in this polyester component. Preferably, the composite fiber has a total crimped rate (TC) of 1 to 10% and a water-absorbed crimped rate of 3 to 20%.

  By taking the constitution of a composite fiber containing 5% to 30% by weight of the water-swellable polyetherester polymer (A) of the present invention, when the water is absorbed, more crimps are expressed, and the apparent length of the yarn is reduced. Water-absorbing shrinkage, reversible crimping performance during drying, stable and excellent crimp rate change characteristics even after dyeing and finishing processes, and unprecedented dyeing fastness Can be obtained.

  The polyamide component which is one component constituting the water-absorbing crimped conjugate fiber of the present invention has an amide bond in the main chain, and examples thereof include nylon 4, nylon 6, nylon 66, nylon 46, nylon 12 and the like. Can be mentioned. Nylon 6 and nylon 66 are particularly preferable from the viewpoints of cost, versatility, and yarn production. In addition, a known component may be copolymerized based on these, and a pigment such as titanium oxide or carbon black, a known antioxidant, an antistatic agent, a light resistance agent, or the like may be contained.

  The polyester component, which is the other component constituting the water-absorbing crimped composite fiber in the present invention, has at least 60 mol% of ethylene terephthalate among the repeating units of the polyester, and 0.5 to 40 mol% of ethylene isophthalate. Is a polyester. If the ethylene terephthalate unit is less than 60 mol%, it is not preferable because basic physical properties such as strength and elongation of the obtained composite fiber cannot be sufficiently maintained. On the other hand, if the ethylene isophthalate is less than 0.5 mol%, it is not suitable because the shrinkage rate of crimp is small when the composite fiber absorbs moisture, and a sufficient moisture-permeable waterproof function is not exhibited when it is made into a fabric. . When ethylene isophthalate exceeds 40 mol%, the basic physical properties such as the strength and elongation of the composite fiber cannot be maintained, the thermal stability is inferior, and the pack pressure rises significantly due to degradable foreign matters in the yarn making process, which is not preferable. .

  Ethylene terephthalate units and ethylene isophthalate units are obtained by directly esterifying terephthalic acid or isophthalic acid with ethylene glycol, or directly esterifying lower alkyl esters of aromatic acids such as terephthalic acid or dimethyl isophthalate with ethylene glycol. Reacting or reacting terephthalic acid or isophthalic acid with ethylene oxide to produce a glycol ester of an aromatic acid and / or its low degree of polymerization, and then heating the product under reduced pressure to produce the desired It is produced by a polycondensation reaction until the degree of polymerization is reached.

  The polyester component may be copolymerized with a third component in addition to the ethylene terephthalate and ethylene isophthalate components constituting the polyester, and the third component may be either a dicarboxylic acid component or a glycol component. Examples of the dicarboxylic acid include isophthalic acid, phthalic acid, dibromoterephthalic acid, naphthalene dicarboxylic acid, diphenyl carboxylic acid, diphenethane carboxylic acid, bifunctional aromatic carboxylic acid such as β-oxyethoxybenzoic acid, and sebacin. Bifunctional aliphatic dicarboxylic acid such as acid, adipic acid and oxalic acid, 1,4-cyclohexanedicarboxylic acid and the like can be mentioned. Further, part of the glycol component may be replaced with another glycol component. Examples of the glycol component include cyclohexane-1,4-dimethanol, neopentyl glycol, bisphenol A, bisphenol S, 2,2-bis (3 , 5-dibromo-4- (2-hydroxyethoxy) phenyl) propane, and aliphatic, alicyclic and aromatic diols. Further, the above-mentioned polyester may be obtained by blending and melting a small amount of other polymers as required, or by using a small amount of a chain branching agent such as pentaerythritol, trimethylolpropane, trimellitic acid or the like. In addition, the polyester of the present invention may be added with pigments such as titanium oxide and carbon black, as well as conventionally known antioxidants and anti-coloring agents in the same manner as ordinary polyesters.

  As the shape of the water-absorbed crimped composite fiber of the present invention, an arbitrary fineness, cross-sectional shape, and composite form can be taken, but a single yarn fineness of about 1.5 to 5.0 dtex is appropriate. Furthermore, when the conjugate fiber of the present invention is a hollow conjugate fiber, it has high sensitivity to humidity and high bulkiness. Moreover, the area ratio in the fiber cross section of a polyamide component and a polyester component has the preferable range of polyamide / polyester = 30 / 70-70 / 30, More preferably, it is the range of 40 / 60-60 / 40.

  The total fineness of the water-absorbed crimped composite fiber of the present invention is not particularly limited as a yarn, but is preferably 40 to 200 dtex used as a normal clothing material. In addition, the confounding process may be performed as needed.

  It is essential that the polyester component constituting the water-absorbing crimped composite fiber of the present invention contains 5% by weight to 30% by weight of the water-swellable polyetherester polymer (A). Thereby, the crimp expression characteristic at the time of water absorption expresses. That is, the polyester component at the time of water absorption does not change greatly in size, but the elastic modulus is lowered by water absorption of the mixed water-swellable polyetherester polymer, while the polyamide swells and expands by water absorption. For this reason, water absorption causes crimping with the polyamide on the outside and the polyester on the outside in the fiber length direction. Therefore, it is essential that the polyether ester polymer (A) has water swellability, and the water swelling rate is 10% or more, preferably 20% or more, more preferably 20 to 100%.

  As this water-swellable polyether ester polymer (A), for example, a polyether ester elastomer having polybutylene terephthalate as a hard segment and polyoxyethylene glycol as a soft segment is preferable. The polybutylene terephthalate which is a hard segment preferably contains at least 70 mol% of butylene terephthalate units. The content of butylene terephthalate is more preferably 80 mol% or more, and still more preferably 90 mol% or more.

  As will be described later, the polybutylene terephthalate is preferably copolymerized with a metal sulfonic acid metal salt represented by the following general formula (1) from the viewpoint of obtaining higher water absorption swellability.

  Other than this, other components may be copolymerized as long as the achievement of the object of the present invention is not substantially impaired. As other copolymerization components, dicarboxylic acid components include, for example, naphthalenedicarboxylic acid, isophthalic acid, diphenyldicarboxylic acid, diphenyloxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid, p-oxybenzoic acid, adipic acid, sebacic acid, Examples thereof include aromatic and aliphatic dicarboxylic acid components such as 1,4-cyclohexanedicarboxylic acid. Furthermore, trifunctional or higher polycarboxylic acids such as trimellitic acid and pyromellitic acid may be used as a copolymerization component. Examples of the diol component include aliphatic, alicyclic, and aromatic diol components such as trimethylene glycol, ethylene glycol, cyclohexane-1,4-dimethanol, and neopentyl glycol. Furthermore, a trifunctional or higher functional polyol such as glycerin, trimethylolpropane, or pentaerythritol may be used as a copolymerization component.

  On the other hand, polyoxyethylene glycol which is a soft segment preferably contains at least 70 mol% of oxyethylene glycol units. The content of oxyethylene glycol is more preferably 80 mol% or more, and still more preferably 90 mol% or more. For example, propylene glycol, tetramethylene glycol, glycerin and the like may be copolymerized with the polyoxyethylene glycol within a range in which the achievement of the object of the present invention is not substantially impaired. The number average molecular weight of polyoxyethylene glycol is preferably 400 to 8000, and particularly preferably 1000 to 6000.

  The hard segment: soft segment weight ratio of the water-swellable polyetherester polymer (A) is preferably in the range of 70:30 to 30:70, more preferably in the range of 60:40 to 40:60. . When the weight ratio of the hard segment exceeds 70%, the swelling deformability in water becomes poor, and sufficient water absorption / absorption performance cannot be obtained. On the other hand, when the weight ratio of the hard segment is less than 30%, the thermal stability is lowered, resulting in a decrease in fiber formation and a deterioration in spinning condition.

The water-swellable polyetherester polymer (A) is preferably copolymerized with an organic sulfonic acid metal salt represented by the following general formula (1). Thereby, the moisture absorption performance can be further improved, and the water swellability can be further improved.

In the formula, R1 is an aromatic hydrocarbon group or an aliphatic hydrocarbon group, preferably an aromatic hydrocarbon group having 6 to 15 carbon atoms or an aliphatic hydrocarbon group having 10 or less carbon atoms, and particularly preferred R1 is An aromatic hydrocarbon group having 6 to 12 carbon atoms, particularly a benzene ring. M1 is an alkali metal or alkaline earth metal, and n is 1 or 2. Among them, those in which M1 is an alkali metal (for example, lithium, sodium or potassium) and n is 1 are preferable. X1 represents an ester-forming functional group, and X2 represents the same or different ester-forming functional group as X1, or represents a hydrogen atom, but is preferably an ester-forming functional group. The ester-forming functional group may be any group that reacts with and bonds to the main chain or terminal of the polyether ester, and specifically includes the following groups.

（上記式中、Ｒ’は低級アルキル基またはフェニル基を示し、ａおよびｄは１〜１０の整数を示し、ｂは２〜６の整数を示す。）

(In the above formula, R ′ represents a lower alkyl group or a phenyl group, a and d represent an integer of 1 to 10, and b represents an integer of 2 to 6.)

  Preferable specific examples of the organic sulfonic acid metal salt represented by the general formula (1) include sodium 3,5-dicarbomethoxybenzenesulfonate, potassium 3,5-dicarbomethoxybenzenesulfonate, 3,5-dicarboxylate. Lithium carbomethoxybenzenesulfonate, sodium 3,5-dicarboxybenzenesulfonate, potassium 3,5-dicarboxybenzenesulfonate, lithium 3,5-dicarboxybenzenesulfonate, 3,5-di (β-hydroxyethoxy) Carbonyl) sodium benzenesulfonate, potassium 3,5-di (β-hydroxyethoxycarbonyl) benzenesulfonate, 3,5-di (β-hydroxyethoxycarbonyl) lithium benzenesulfonate, 2,6-dicarbomethoxynaphthalene 4-sulphonic acid sodium rim, 2 Potassium 6-dicarbomethoxynaphthalene-4-sulfonate, lithium 2,6-dicarbomethoxynaphthalene-4-sulfonate, sodium 2,6-dicarboxynaphthalene-4-sulfonate, 2,6-dicarbomethoxysulfate Sodium tarene-1-sulfonate, sodium 2,6-dicarbomethoxynaphthalene-3-sulfonate, sodium 2,6-dicarbomethoxynaphthalene-4,8-sodium disulfonate, 2,6-dicarboxynaphthalene-4, Examples thereof include sodium 8-disulfonate, sodium 2,5-bis (hydroethoxy) benzenesulfonate, α-sodium sulfosuccinic acid, and the like. The said organic sulfonic acid metal salt may be used individually by 1 type, or may be used together 2 or more types.

  If the copolymerization amount of the organic sulfonic acid metal salt is too large, the melting point of the water-swellable polyether ester (A) tends to decrease and the heat resistance and chemical resistance tend to decrease. The range of 0.1-20 mol% is preferable on the basis of the total acid components to constitute, and more preferably 0.5-15 mol%.

  The water-swellable polyether ester (A) used in the present invention is obtained by subjecting a raw material containing, for example, dimethyl terephthalate, tetramethylene glycol, and polyoxyethylene glycol to a transesterification reaction in the presence of a transesterification catalyst. -Hydroxybutyl) terephthalate and / or oligomers can be formed and then subjected to melt polycondensation under high temperature and reduced pressure in the presence of a polycondensation catalyst and a stabilizer.

  As the transesterification catalyst, an alkali metal salt such as sodium, an alkaline earth metal salt such as magnesium or calcium, or a metal compound such as titanium, zinc or manganese is preferably used.

  As the polycondensation catalyst, it is preferable to use a germanium compound, an antimony compound, a titanium compound, a cobalt compound, or a tin compound. The amount of the catalyst used is not particularly limited as long as it is a necessary amount for proceeding the transesterification reaction and polycondensation reaction, and a plurality of catalysts can be used in combination.

  The transesterification catalyst can be supplied at the initial stage of the transesterification reaction in addition to the preparation of the raw material. The stabilizer can be supplied before the beginning of the polycondensation reaction, but it is preferably added at the end of the transesterification reaction. Furthermore, the polycondensation catalyst can be supplied by the early stage of the polycondensation reaction step.

  The water-swellable polyetherester polymer (A) is not added to the polyamide. If even a small amount is added, the hygroscopic elongation property of the polyamide is lowered, and the function that the crimp is expressed at the time of moisture absorption, which is the object of the present invention, and the yarn length is shortened is impaired. The amount added to the polyester is required to be 5 to 30% by weight. If it is less than 5% by weight, the expression of crimps is small when the composite fiber absorbs moisture, and a sufficient moisture-permeable and waterproof function is not expressed when it is made into a fabric. On the other hand, if it exceeds 30% by weight, it is not preferable because, on the contrary, water-absorbing elongation is exhibited and spinning cannot be performed stably.

  In the present invention, the crimped rate (TC) of the water-absorbed crimped composite fiber after 30 minutes of boiling water treatment is 1 to 10%. It is important that the water absorption crimp rate is 3 to 20%. If the crimp ratio (TC) is lower than 1%, the crimp is too low and the texture before water absorption is inferior, and if it exceeds 10%, the water absorption crimp effect is hardly exhibited. A preferable range of the crimp rate (TC) is 2 to 5%. Further, the water absorption crimp rate is set in consideration of the dyeing and setting process, and if it is less than 3%, the change in air permeability and waterproofness is poor, and sufficient performance can be obtained when used as a fabric. On the other hand, if it is 20% or more, it becomes an area that is difficult to produce stably on yarn production. Preferably it is 5 to 15%.

  Although it is a form of the water-absorbing crimped composite fiber of the present invention, it is basically necessary to have a form in which the polyester component is disposed inside the crimped form and the polyamide component is disposed outside the crimped form. This is because, in this form, the polyamide component is stretched by absorbing water and crimps are further increased. In that sense, it is preferable that neither the polyester component nor the polyamide component increase the crystallinity. However, if the crystallinity is too low, it becomes impossible to withstand the heat treatment with the second stretching roller, and as a result, the stretchability is lowered, which is not preferable.

In the water-absorbed crimped composite fiber of the present invention, the hygroscopic rate MR1 after the composite fiber is left in an atmosphere of 20 ° C. and 65% RH for 4 hours, and the composite fiber is left in an atmosphere of 35 ° C. and 95% RH for 4 hours. When the moisture absorption rate MR2 is set, the moisture absorption rate difference ΔMR represented by the following formula is preferably 2.0% or more from the viewpoint of comfort when used as a woven or knitted fabric.
ΔMR = MR2-MR1

Hereinafter, a production method for obtaining the water-absorbed crimped composite fiber of the present invention will be described.
Any conventionally known method can be employed for the composite spinning of the polyamide component and the polyester component in a side-by-side manner. The yarn obtained by spinning is first wound up, then stretched, and further subjected to heat treatment as necessary. In addition to the so-called separate stretching method, the unstretched yarn is stretched once without being wound, and if necessary. Either of the so-called direct extension methods, in which heat treatment is performed, can be employed. As the spinning speed in the above spinning, for example, a spinning speed of about 1000 to 3500 m / min which is usually employed can be adopted. In addition, in the stretching and heat treatment, it is preferable in view of crimping, weaving and knitting, and the like to set conditions so that the cut elongation after stretching is about 10 to 60%, usually about 20 to 45%.

  In order to express crimp in the water-absorbed crimped composite fiber of the present invention, it is first treated with boiling water. As a result, a composite fiber having a crimp structure in which the nylon component is positioned outside the crimp and the polyester component is positioned inside the crimp in the length direction of the fiber is obtained. (Refer to FIG. 1) 只 In this state, since moisture is contained, the polyamide stretches due to the plasticizing effect of water, so that the crimp changes with time and becomes unstable. It is necessary to stabilize the crimp by removing moisture. In general, the raw yarn is subjected to hot water treatment such as dyeing after weaving and weaving, followed by dry heat treatment at 160 ° C. or higher after drying.

  The water-absorbed crimped composite fiber of the present invention can be used alone or as a mixed yarn mixed with other fibers. Further, if necessary, false twisting can be further used as a false twisted yarn, and it can also be used as a composite false twist having different elongations.

  The form using the water-absorbed crimped conjugate fiber of the present invention as at least a part of the present invention is not particularly limited in its form such as woven or knitted fabric, non-woven fabric or felt. Further, the fabric can be prepared by mixing with various synthetic fibers together with the water-absorbed crimped composite fiber of the present invention. Of course, even more effective in the composite of the present water-absorbed crimped composite fiber and natural fiber, and further, in combination with urethane or polytrimethylene terephthalate, it can be used with further stretchability. I do not care.

  The water-absorbed crimped conjugate fiber of the present invention can be used for various uses for clothing, for example, in swimwear, various sportswear, inner materials, uniforms, and other applications that require comfort. Can do.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these examples are for helping the understanding of the present invention, and the description is not intended to limit the examples to be consistent with the gist of the present invention. In addition, each physical-property value in an Example was measured with the following method.

(1) Water swelling rate A water-swellable polyetherester polymer is spun independently at a hole diameter of 0.4 mm and a discharge rate of 2 g / min / hole to form a single yarn of 40 dtex in an atmosphere of 20 ° C and 65% RH. After standing for 12 hours, it was cut into a length of 10 cm. The length was measured again immediately after being immersed in water at 20 ° C. for 10 minutes, and the length was calculated by the following formula as X (cm).
Water swelling rate (%) = (X−10) / 10 × 100 (%)

(2) Total crimp rate (TC)
A 2700 dtex multifilament made of the water-absorbing crimped composite fiber of the present invention is used to make a cocoon with a length of 30 cm, under a heavy load of 600 g (220 mg / dtex) and a light load of 6 g (2.2 mg / dtex). The respective lengths were measured and designated as L0 and L1. After 30 minutes of treatment in boiling water, the crimps appear, then lightly remove the water with filter paper, and again under a heavy load of 600 g (220 mg / dtex) and a light load of 6 g (2.2 mg / dtex), respectively. Were measured as L2 and L3, and calculated by the following formula.
Crimp rate (TC) (%) = (L2-L3) / L0 × 100 (%)

(3) Water-absorbing crimp rate Using a 2700 dtex multifilament made of the water-absorbed crimped composite fiber of the present invention, a wrinkle having a length of 30 cm is formed, and a load of 6 g (2.2 mg / dtex) is applied for 30 minutes in boiling water. It was crimped to develop it, then naturally dried for 24 hours, and further subjected to a dry heat treatment at a temperature of 160 ° C. for 1 minute. The sample was allowed to stand under an atmosphere of 65% RH at 20 ° C. for 12 hours under a load of 6 g (2.2 mg / dtex), and the composite fiber was immersed in water for 2 minutes under no load. A load of 6 g (2.2 mg / dtex) was applied within 1 minute, the measured yarn length L5 was measured, and calculated using the following formula.
Water absorption crimp rate (%) = (L4-L5) / L4 X 100 (%)

(4) Shape change of cylinder knitting The water-absorbing crimped conjugate fiber of the present invention was knitted, dyed by boil, set in a dry heat at 160 ° C. for 1 minute after washing with water, and used as a measurement sample. Water was dropped on the tubular knitting, the situation of the water dripping portion and its surroundings was investigated with a side photograph (magnification 200) of the tubular knitting, and the swelling or shrinkage of the stitch due to the dripping was determined with the naked eye.
Good: The stitches are significantly shrunk with water drops.
Slightly poor: Almost no change in stitches due to water droplets.
Defect: The stitch is rather elongated with water droplets.

(5) Moisture absorption rate The moisture-absorbed crimped composite fiber of the present invention is conditioned for 4 hours in a constant temperature and humidity chamber at 20 ° C. × 65% RH or 35 ° C. × 95% RH. The moisture absorption rate was determined from the weight of
Moisture absorption rate MR (%) = (weight after conditioning-weight when completely dried) × 100 / weight when completely dried

(6) Difference in moisture absorption rate (ΔMR)
The difference in moisture absorption rate (ΔMR) is as follows: moisture absorption rate MR1 after leaving in an atmosphere of 20 ° C. and 65% RH for 4 hours, moisture absorption rate MR2 after leaving the composite fiber in an atmosphere of 35 ° C. and 95% RH for 4 hours. Is a value calculated using the following formula.
ΔMR = MR2-MR1

[Examples 1-3, Comparative Examples 1-2]
The water-swellable polyetherester polymer (A) used was produced by the following method. That is, 100 parts by weight of dimethyl terephthalate, 23 parts by weight of a 40% by weight ethylene glycol solution of sodium 3,5-di (β-hydroxyethoxycarbonyl) benzenesulfonate (5.0 mol% based on the total acid components), polyethylene glycol (Number average molecular weight 4000) 113.4 parts by weight, 1,4-butanediol 73.5 parts by weight (1.4 mol times the total acid component), and 0.4 parts by weight of tetrabutyl titanate as a catalyst were charged into the reaction vessel. The transesterification was carried out at an internal temperature of 200 ° C. When about 80% of the theoretical amount of methanol was distilled, 0.4 parts by weight of the above-mentioned hindered phenol compound stabilizer was added, and the polycondensation reaction was started by raising the temperature and reducing the pressure. The polycondensation reaction is 30 mmHg over about 30 minutes, then 3 mmHg over 30 minutes. Thereafter, the reaction is performed for 200 minutes at an internal temperature of 250 ° C. under a vacuum of 1 mmHg, and further at 250 ° C under a vacuum of 1 mmHg or less for 20 minutes. Reacted for 20 minutes. The produced water-swellable polyetherester elastomer (A) had an intrinsic viscosity of 1.10, and the weight ratio of polybutylene terephthalate (hard segment) / polyethylene glycol (soft segment) was 50/50. The water swelling rate was 12%.

  Isophthalic acid copolymer polyethylene terephthalate chip (IV = 0.65, isophthalic acid copolymer) in which nylon 6 (Ny6) having an intrinsic viscosity (IV) of 1.2 and the water-swellable polyetherester polymer (A) are chip-blended. Mole ratio is melted separately in Table 1), and is spun at a spinning temperature of 280 ° C. and a spinning speed of 1000 m / min using a known side-by-side type composite spinning device, and then stretched at a stretching temperature of 60 ° C. without winding. 84dtex / 24fil composite stretched at 2.5x magnification and heat-set at 130 ° C and joined to side-by-side with a weight ratio of nylon 6 and polyethylene terephthalate blended with polyetheresteramide at 50:50 Fiber was obtained. The physical properties of the obtained composite fiber are shown in Table 1. Examples 1, 2, and 3 are isophthalic acid copolymerization ratios within the scope of the present invention, and since the addition amount of the water-swellable polyetherester polymer is appropriate, the water absorption shrinkage rate and the moisture absorption rate are satisfied. A composite fiber excellent in quality was obtained.

  In Comparative Example 1, since isophthalic acid was not copolymerized, the side-by-side type fiber had poor flexibility on the PET side, and was insufficient in terms of water absorption crimp. In Comparative Example 2, since the copolymerization ratio of isophthalic acid was large, the heat resistance of the PET polymer was insufficient, the pack pressure was significantly increased by the pyrolyzate, and continuous yarn production was impossible.

[Examples 4-6, Comparative Examples 3-4]
The amount of the water-swellable polyetherester polymer (A) added to the PET side was changed as shown in Table 1, and composite fibers were obtained in the same manner as in Example 1. In Examples 4 to 6, since the addition amount of (A) was appropriate, performance satisfying the present invention was obtained. On the other hand, in Comparative Example 3, since (A) was not added, the PET-side flexibility was poor, and the performance was insufficient in terms of moisture absorption crimp expression. In Comparative Example 4, since the amount of (A) added was large, the discharge on the PET side was not stabilized and continuous yarn production was impossible.

[Comparative Example 5]
Relative viscosity of 2.2 (0) derived from a bisphenol ethylene oxide adduct having a number average molecular weight of 2000 and a polyamide having a number average molecular weight of 1,500 having a carboxyl group at both ends without using the water-swellable polyether ester polymer (A). A sample was obtained in the same manner as in Example 1 using a polyether ester amide of 5 wt% m-cresol solution (25 ° C.). Although the water absorption crimp rate was good, the dyeing fastness with a disperse dye was remarkably low, and it was difficult to put it into practical use.

  By using the conjugate fiber of the present invention, the change in crimp rate reversibly during water absorption and drying is stabilized, and therefore, a fabric having moisture-permeable and waterproof properties can be obtained.

Schematic diagram of crimped structure

Explanation of symbols

PA: Polyamide PES: Polyester

Claims (3)

A water-absorbed crimped composite fiber, which is a composite fiber in which a polyamide component and a polyester component are bonded in a side-by-side manner and satisfies the following requirements a) to b).
a) The polyester component is a copolyester in which at least 60 mol% of units constituting the polyester are occupied by ethylene terephthalate units and 0.5 to 40 mol% is occupied by ethylene isophthalate units.
b) 5% to 30% by weight of the water-swellable polyetherester polymer (A) is contained in the polyester component.   The water-absorbed crimped composite fiber according to claim 1, wherein the composite fiber has a total crimp rate (TC) of 1 to 10% and a water absorption crimp rate of 3 to 20%. The water-swellable polyether ester polymer (A) is a polyether ester polymer having polybutylene terephthalate as a hard segment and polyoxyethylene glycol as a soft segment, and is an organic sulfonic acid metal salt represented by the following general formula (1) The water-absorbing crimped composite fiber according to any one of claims 1 and 2, wherein is copolymerized in a range of 0.1 to 20 mol% based on an acid component constituting the water-swellable polyetherester polymer.

(Wherein R1 is an aromatic hydrocarbon group or aliphatic hydrocarbon group, X1 is an ester-forming functional group, X2 is the same or different ester-forming functional group or hydrogen atom as X1, or M1 is an alkali metal or alkaline earth) Metal, n represents 1 or 2)

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