WO2010101182A1

WO2010101182A1 - Moisture absorbing fiber dyeable with cationic dye, and method for producing same

Info

Publication number: WO2010101182A1
Application number: PCT/JP2010/053435
Authority: WO
Inventors: 藤本克也; 安藝泰雄; 家野正雄
Original assignee: 日本エクスラン工業株式会社
Priority date: 2009-03-06
Filing date: 2010-03-03
Publication date: 2010-09-10

Abstract

Disclosed is a low-cost moisture absorbing fiber which can be practically dyed with a cationic dye and can sufficiently develop a color with the cationic dye, while maintaining the characteristics of a crosslinked acrylic acid-based fiber. Specifically disclosed is a moisture absorbing fiber dyeable with a cationic dye, which is obtained by crosslinking and hydrolyzing an acrylonitrile fiber that contains not less than 0.03 mmol/g of sulfonic acid groups relative to the weight of the fiber. The moisture absorbing fiber dyeable with a cationic dye is characterized in that the fiber is composed of a region of a crosslinked acrylic acid polymer having a carboxyl group and a crosslinked structure, and a region of an acrylonitrile polymer having a sulfonic acid group. The moisture absorbing fiber dyeable with a cationic dye is also characterized in that the region of the acrylonitrile polymer is within the range of 20-80%.

Description

Cationic dye-dyeable hygroscopic fiber and method for producing the same

The present invention relates to a dye-dyeable hygroscopic fiber composed of a crosslinked acrylic acid polymer and an acrylonitrile polymer, and a production method.

As fibers having moisture absorption / release properties, cotton, wool, rayon, acetate, cross-linked acrylic acid fibers and the like are known, among which cross-linked acrylic acid fibers are compared with other natural fibers having moisture absorption / release properties, It is known to have a characteristic of having a high moisture absorption rate. Such cross-linked acrylic fiber has a carboxyl group that functions as a dyeing seat, and it is possible to color the fiber with a cationic dye, but the ion bond between the carboxyl group and the dye is weak, so that the ion exchange is easy. Since the dyeing fastness is poor, a practical level of dyeing cannot be performed.

In order to solve the problem relating to the dyeing, for example, Patent Documents 1 and 2 propose a dyeing method using a reactive dye of a crosslinked acrylic fiber. In these methods, although the fastness to dyeing is improved by using reactive dyes, the problem of dyeing with cationic dyes has not been solved, and when a fiber structure mixed with cellulosic fibers is dyed. However, there is a case in which the hue with the cellulosic fiber is different, and there is a difficulty in practical color matching. In addition, there is a problem that the pH during dyeing needs to be a strongly acidic condition, and that it is necessary to deal with facilities such as restrictions on mixed fibers and countermeasures against corrosion.

On the other hand, Patent Document 3 proposes a fiber in which a sulfonic acid group is introduced by impregnating and polymerizing a monomer having a sulfonic acid group into a raw material fiber having a carboxyl group. Although this fiber can introduce a large amount of sulfonic acid groups and is colored with a cationic dye, it has been difficult to obtain sufficient color developability, dyeing fastness and hue stability. In addition, since a method of introducing a sulfonic acid group by impregnating and polymerizing a monomer having a sulfonic acid group into a raw fiber is employed, there is a problem that a complicated operation is required and the cost is increased.

JP 2003-278079 A JP 2006-70421 A JP 2008-174849 A

As described above, conventional cross-linked acrylic fiber has harmonious functions such as pH buffering, antistatic properties, water retention, high moisture absorption rate, high moisture absorption rate, high moisture absorption difference or temperature control and humidity control functions derived therefrom. However, it still has a problem with dyeability. Based on the present situation, the present invention is capable of practical dyeing with sufficient coloring property and fastness by a cationic dye while retaining the characteristics of the conventional crosslinked acrylic fiber, and is a low-cost hygroscopic fiber. The purpose is to provide.

As a result of diligent studies to achieve the above-mentioned object, the present inventor has reached the present invention shown below.

(1) A hygroscopic fiber obtained by crosslinking and hydrolyzing an acrylonitrile-based fiber having a sulfonic acid group of 0.03 mmol / g or more with respect to the fiber weight, and the fiber has a carboxyl group and a crosslinked structure. Cationic dye dyeable, characterized by comprising a cross-linked acrylic acid polymer region and a sulfonic acid group-containing acrylonitrile polymer region, and the acrylonitrile polymer region is 20 to 80%. Hygroscopic fiber.
(2) The hue of the fiber after dyeing with a cationic dye as defined below is such that L * in the L * a * b * color system (JIS-Z8729) is +45 or less, a * is −5 or more and +5 or less, b * The cationic dye-dyeable hygroscopic fiber according to (1), wherein is from −5 to +5.
Color of fiber after dyeing with cationic dye: 1 g of hygroscopic fiber, 3.3 dtex, and 2 g of acrylonitrile fiber with a saturated dyeing amount of 1.8 g of Malacite Green, with respect to the total fiber weight (3 g) (2.5% by weight) and an acetic acid (2% by weight) aqueous solution for 30 minutes, then immersed in an aqueous solution of hydrosulfite 2 g / L for 15 minutes at 60 ° C., then washed with running water for 5 minutes and then air-dried And dyed hygroscopic fibers are obtained by removing the acrylonitrile fibers. Hue when the dyed hygroscopic fibers are opened, packed in a cylindrical cell whose bottom surface is a quartz glass surface, and measured using a spectrocolorimeter.
(3) Acrylic sulfonic acid group-containing resin 1 in which the acrylonitrile fiber contains 90 to 99% by weight of an acrylonitrile polymer containing 80% by weight or more of acrylonitrile and the balance contains 10 to 70% by weight of acrylonitrile. The cationic dye-dyeable hygroscopic fiber according to (1) or (2), which is composed of a polymer of ˜10% by weight.
(4) The acrylonitrile fiber is composed of at least two acrylonitrile polymers having different acrylonitrile contents, and the difference in the contents is 2% by weight or more (1) to (3) The dye-dyeable hygroscopic fiber according to any one of the above.
(5) The method for producing a dye-dyeable hygroscopic fiber according to any one of (1) to (4), wherein acrylonitrile fiber is crosslinked, hydrolyzed, and further subjected to heat treatment.

The cationic dye-dyeable hygroscopic fiber of the present invention has high hygroscopic performance and is excellent in color developability by the cationic dye, so that practical dyeing is possible. Therefore, it can be developed in applications where the use of conventional cross-linked acrylic acid fibers is restricted because practical dyeing has been difficult.

Hereinafter, the present invention will be described in detail. The cationic dye-dyeable hygroscopic fiber of the present invention is a hygroscopic fiber obtained by crosslinking and hydrolyzing an acrylonitrile-based fiber having a sulfonic acid group of 0.03 mmol / g or more based on the fiber weight, It is a fiber having a structure comprising a region of a crosslinked acrylic acid polymer having a carboxyl group and a crosslinked structure and a region of an acrylonitrile polymer having a sulfonic acid group. The sulfonic acid group in the region of the acrylonitrile polymer may be contained in the acrylonitrile polymer itself or may be contained in another polymer contained in the region of the acrylonitrile polymer. The cationic dye-dyeable hygroscopic fiber of the present invention may be composed only of a cross-linked acrylic acid polymer region and an acrylonitrile polymer region, or an acrylic acid polymer region and an acrylonitrile polymer weight. There may be a region where these are mixed between the combined regions. Moreover, the area | region comprised with a polymer different from these polymers may exist.

The region of the cross-linked acrylic acid polymer having such a carboxyl group and a cross-linked structure is a part mainly responsible for moisture absorption performance. As described above, although the carboxyl group present in such a region functions as a dyeing seat, the ion bond with the dye is weak and the ion exchange is easy, so the dyeing fastness is poor and a practical level dyeing cannot be performed. The region other than the cross-linked acrylic acid polymer is a portion mainly responsible for the dyeing performance. Therefore, the existence of such a region and its dyeing ability are important. In the cationic dyeable and hygroscopic fiber of the present invention, by incorporating a sulfonic acid group functioning as a dyeing seat in such a region, it becomes possible to dye with the same formulation as in the case of acrylonitrile fiber. is there.

As for the ratio of the cross-linked acrylic acid polymer region to the acrylonitrile polymer region, the higher the proportion of the cross-linked acrylic polymer region, the higher the moisture absorption rate. When the ratio of the area of the polymer is reduced and sufficient color developability is to be obtained, it is necessary to increase the concentration of the sulfonic acid group in the area of the acrylonitrile polymer. Therefore, it is necessary that the acrylonitrile-based polymer occupies an area of 20 to 80% of the fiber cross-sectional area in the dry state, and preferably 30 to 70%. Within such a range, a fiber in which both hygroscopicity and color development are balanced can be obtained.

Here, the cross-linked acrylic acid polymer region and the acrylonitrile polymer region are dyed with a cationic dye, then the fiber cross section is observed with an optical microscope, and the dyed region is an acrylonitrile polymer region. The region that is not dyed or in which the dyeing cannot be confirmed is the region of the crosslinked acrylic acid polymer. Therefore, the above-mentioned area ratio is calculated by cutting the dried fiber and observing the fiber cross section after the dyeing treatment.

Furthermore, it is necessary that the acrylonitrile fiber as the raw fiber has a sulfonic acid group of 0.03 mmol / g or more with respect to the fiber weight, preferably 0.05 mmol / g or more, more preferably 0. It is desirable to have a sulfonic acid group of 0.055 mmol / g or more, more preferably 0.065 mmol / g or more. By using such acrylonitrile fiber as a raw material fiber, crosslinking and hydrolysis can yield a cationic dye-dyeable hygroscopic fiber having excellent dyeability.

The dyeability of the cationic dyeable hygroscopic fiber of the present invention includes the hue of the hygroscopic fiber after dyeing in the same bath dyeing with the acrylonitrile fiber by the cationic dye, L * is +45 or less, and a * is −5. It is preferably +5 or less and b * is −5 or more and +5 or less, more preferably L * is +40 or less, and further preferably L * is +35 or less. If the upper limit of L * in this range is exceeded, sufficient color developability may not be obtained, and if it falls outside the range of a * and b *, it will be difficult to adjust the hue, and practical dyeing will be difficult. There is a case.

Furthermore, the acrylic sulfonic acid group-containing resin 1 to 90 contains 90 to 99% by weight of an acrylonitrile-based polymer containing 80% by weight or more of acrylonitrile and the remaining 10 to 70% by weight of acrylonitrile. It is preferably composed of 10% by weight of a polymer. Thereby, a sufficient amount of sulfonic acid groups can be easily introduced into the acrylonitrile fiber.

It is also preferable that the acrylonitrile fiber is composed of at least two acrylonitrile polymers having different acrylonitrile contents, and the difference in the contents is 2% by weight or more. As a result, a difference in ease of crosslinking and hydrolysis occurs, and a region of the crosslinked acrylic acid polymer and a region of the acrylonitrile polymer having a sulfonic acid group are easily formed. Such an acrylonitrile fiber may be one in which two kinds of acrylonitrile polymers are joined side by side or may be randomly mixed, but one having a three-layer structure composed of ABA layers, Alternatively, a core-sheath structure is more preferable, and the B layer or the core part preferably has a high acrylonitrile content and has many sulfonic acid groups. Specifically, the acrylonitrile content in the B layer or the core portion is preferably 82% by weight or more, more preferably 85% by weight or more, and still more preferably 90% by weight or more. Is preferably 0.05 mmol / g or more, more preferably 0.07 mmol / g or more, and still more preferably 0.1 mmol / g or more.

As a method for producing the dye-dyed hygroscopic fiber of the present invention described above, an acrylonitrile fiber is introduced with a nitrogen-containing compound having two or more nitrogen atoms in one molecule, and an alkaline metal salt aqueous solution is introduced. The method of partially forming a cross-linked acrylic acid polymer region by hydrolyzing by the above-mentioned method or carrying out these treatments at the same time and leaving the region of the acrylonitrile polymer containing the amount of sulfonic acid group is the manufacturing equipment and cost. It is desirable from the aspect of. This method will be described in detail below.

Here, the starting acrylonitrile fiber (hereinafter sometimes referred to as acrylic fiber) contains acrylonitrile (hereinafter also referred to as AN) in an amount of 40% by weight or more, preferably 50% by weight or more, more preferably 80% by weight or more. The fibers are formed from AN polymer, and may be in any form such as short fibers, tows, yarns, knitted fabrics, and non-woven fabrics. The AN polymer may be either an AN homopolymer or a copolymer of AN and another monomer. Examples of the other monomer include methyl (meth) acrylate, ethyl (meth) acrylate, (Meth) acrylic acid ester compounds such as butyl (meth) acrylate, dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate, sulfonic acid group-containing compounds such as methallylsulfonic acid and p-styrenesulfonic acid A monomer and a salt thereof; the monomer is not particularly limited as long as it is a monomer copolymerizable with AN, such as a monomer such as styrene and vinyl acetate, but 5 to 20% by weight of a vinyl ester compound represented by vinyl acetate. It is desirable to copolymerize. Such vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate and the like.

In addition, in the starting acrylonitrile fiber employed in the present invention, it is necessary to have a sulfonic acid group of 0.03 mmol / g or more with respect to the fiber weight, so that the acrylonitrile polymer itself has a sulfonic acid group. If it is, a method of introducing a sulfonic acid group at the terminal by a redox catalyst or a method of copolymerizing a sulfonic acid group-containing monomer can be adopted, and the sulfonic acid group is introduced by another polymer. In this case, a method of mixing a sulfonic acid group-containing resin or the like with an acrylonitrile-based polymer can be employed.

Examples of the monomer containing a sulfonic acid group include vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, 4-sulfobutyl (meth) acrylate, methallyloxybenzene sulfonic acid, allyloxybenzene sulfonic acid, 2 -Acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth) acrylate and metal salts of these monomers.

The sulfonic acid group-containing resin is not particularly limited as long as it contains a sulfonic acid group, but the above-described monomer containing a sulfonic acid group and a nitrile group such as acrylonitrile or methacrylonitrile are used. It is preferably an acrylic sulfonic acid group-containing resin obtained by copolymerizing a monomer having the above-mentioned monomers, and other monomers may be copolymerized in addition to such monomers. Examples of such acrylic sulfonic acid group-containing resins include acrylic sulfonic acid group-containing resins composed of acrylonitrile / acrylic acid methyl ester / styrene parasulfonic acid soda monomer, which are mixed uniformly with an acrylonitrile polymer. Alternatively, it may be mixed locally such as side-by-side.

Moreover, as mentioned above, when using 2 or more types of AN polymers, it is desirable that the difference in the content of acrylonitrile is 2% by weight or more. In addition, as a method for obtaining an acrylic fiber having a three-layer structure composed of an ABA layer, the method described in Japanese Patent Application Laid-Open No. 2000-45126 can be employed. It is preferable to reduce the exposure of the B component to the fiber surface by lowering the viscosity of the stock solution.

The acrylic fiber is subjected to a crosslinking introduction treatment with an aqueous solution containing a nitrogen-containing compound having two or more nitrogen atoms in one molecule and a hydrolysis treatment with an aqueous solution containing an alkaline metal salt compound. These treatments can be carried out by individual treatment in which hydrolysis treatment is performed after the cross-linking introduction treatment, or an aqueous solution in which a nitrogen-containing compound having two or more nitrogen atoms in one molecule and an alkaline metal salt compound coexist is used. It can also be performed by simultaneous processing. In any case, a cross-linked structure is formed by the reaction of the nitrogen-containing compound having two or more nitrogen atoms in one molecule and the nitrile group of the acrylonitrile polymer of acrylic fiber, and an aqueous alkali metal salt compound solution A nitrile group reacts to form a carboxyl group, which is converted into a crosslinked acrylic acid polymer.

Specific examples of the crosslinking introduction treatment and the hydrolysis treatment include a method in which a fiber is immersed in an aqueous solution used for the treatment, a method in which the aqueous solution is sprayed, and a method in which the aqueous solution is adhered to the fiber. Can be adopted. In both cases of individual treatment and simultaneous treatment, the concentration of the nitrogen-containing compound having two or more nitrogen atoms in one molecule is preferably 0.1 to 5% by weight, more preferably 0.1%. ~ 2% by weight. If this concentration is too low, the effect of suppressing the dissolution of the acrylic acid polymer may not be obtained. If it is too high, the coloring of the fiber becomes strong, or it becomes impossible to introduce a carboxyl group sufficient to develop sufficient hygroscopicity. There is a fear. The concentration of the alkaline metal salt compound is preferably 0.5 to 5% by weight, more preferably 0.5 to 4% by weight. If the concentration of the alkaline metal salt compound is too low, the amount of carboxyl groups produced may be insufficient, and if it is too high, the acrylonitrile polymer to be left behind may be hydrolyzed.

Moreover, about reaction temperature and time, the suitable range changes according to the density | concentration of the nitrogen-containing compound and / or alkaline metal salt compound which have a 2 or more nitrogen atom in 1 molecule. In the case of simultaneous treatment, if the concentration of the nitrogen-containing compound having two or more nitrogen atoms in one molecule is about 0.5 to 2% by weight and the concentration of the alkaline metal salt compound is about 1 to 2% by weight, Conditions of 90 to 100 ° C for about 2 hours are recommended.

Here, the nitrogen-containing compound having two or more nitrogen atoms in one molecule is preferably an amino compound or a hydrazine-based compound having two or more primary amino groups. Examples of amino compounds having two or more primary amino groups include diamine compounds such as ethylenediamine and hexamethylenediamine, diethylene and reamine, 3,3′-iminobis (propylamine), N-methyl-3, 3′- Triamine compounds such as iminobis (propylamine), triethylenetetramine, N, N′-bis (3-aminopropyl) -1,3-propylenediamine, N, N′-bis (3-aminopropyl) -1, Examples include tetraamine compounds such as 4-butylenediamine, polyamine compounds having two or more primary amino groups such as polyvinylamine and polyallylamine. Examples of the hydrazine-based compound include hydrazine hydrate, hydrazine sulfate, hydrazine hydrochloride, hydrazine bromate, and hydrazine carbonate. The upper limit of the number of nitrogen atoms in one molecule is not particularly limited, but is preferably 12 or less, more preferably 6 or less, and particularly preferably 4 or less. When the number of nitrogen atoms in one molecule exceeds the above upper limit, the cross-linking agent molecule becomes large and it may be difficult to introduce cross-linking into the fiber. Moreover, it does not specifically limit as an alkaline metal salt compound, An alkali metal hydroxide, an alkaline-earth metal hydroxide, an alkali metal carbonate, etc. can be used.

In the case of the above individual treatment, the fiber that has undergone the cross-linking introduction treatment may be subjected to an acid treatment before the hydrolysis treatment. By this acid treatment, the coloring of the fiber can be lightened. Examples of the acid used here include aqueous solutions of mineral acids such as nitric acid, sulfuric acid, and hydrochloric acid, and organic acids, but are not particularly limited. Examples of the treatment conditions include immersing the fiber to be treated in an aqueous solution having an acid concentration of 5 to 20% by weight, preferably 7 to 15% by weight, at a temperature of 50 to 120 ° C. for 0.5 to 10 hours. Further, after hydrolysis or simultaneous crosslinking / hydrolysis treatments, treatments such as washing with an acidic aqueous solution adopted by conventional crosslinked acrylic fibers, pH adjustment treatment with a buffer solution, etc. may be performed.

Although the cationic dye-dyeable hygroscopic fiber of the present invention can be obtained by the above method, it is preferable to further perform heat treatment. The step of performing the heat treatment may be performed during any of the above steps, and may be before the cross-linking hydrolysis or after all the steps of the above steps are completed, but after the cross-linking hydrolysis or with an acidic aqueous solution. It is desirable to carry out after washing. By this heat treatment, the color developability can be further improved.

The heat treatment may be wet heat or dry heat, but it is desirable that the heat treatment be performed with hot water at 100 to 130 ° C. for 10 seconds or longer, preferably for 10 minutes or longer. In addition, when the sulfonic acid group of the acrylonitrile fiber is 0.05 mmol / g or more, or when the sulfonic acid group of the acrylonitrile group-containing resin is contained in an amount of the sulfonic acid group or more, two or more kinds of AN-based fibers are used. When a polymer is used, it is not always necessary, but it is preferable to perform a heat treatment in order to obtain more excellent color developability.

The amount of carboxyl groups in the portion made of the crosslinked acrylic acid polymer is preferably 1.0 to 10 mmol / g, more preferably 2.0 to 5.0 mmol / g, based on the fiber weight. If the lower limit of the range is not reached, sufficient moisture absorption performance may not be obtained, and if the upper limit is exceeded, the color developability when cationic dyeing may not be obtained. The carboxyl group may be a carboxylic acid or a carboxylate salt, or they may be mixed, but in the stage after fiber production, a carboxylic acid is used to facilitate processing such as spinning, After dyeing or at the final product stage, it is desirable that 50% or more is a carboxylate in order to obtain a high moisture absorption rate.

Examples of cations constituting the carboxylate include alkali metals such as Li, Na, and K, alkaline earth metals such as Be, Ca, and Ba, Cu, Zn, Al, Mn, Ag, Fe, and Co. And a metal such as Ni, a cation such as ammonium and amine, and a plurality of types of cations may be mixed.

EXAMPLES The present invention will be specifically described below with reference to examples, but this is illustrative only and the present invention is not limited thereto. In the examples, parts and percentages are shown on a weight basis unless otherwise specified. The evaluation method of characteristics in the examples is as follows.

(1) Carboxyl group amount (mmol / g)
About 1 g of a well-dried sample was precisely weighed (Yg), 200 mL of water was added thereto, 1 mol / L hydrochloric acid aqueous solution was added to the solution while being heated to 50 ° C. to pH 2, and then 0.1 mol / L A titration curve is obtained with an aqueous sodium hydroxide solution according to a conventional method. The consumption amount (ZmL) of the aqueous sodium hydroxide solution consumed by the carboxyl groups was determined from the titration curve, and the carboxyl group amount (mmol / g) was calculated by the following formula.
(Carboxyl group amount) = 0.1 Z / Y

(2) Saturated moisture absorption (%)
About 5.0 g of the sample is immersed in water, an aqueous sodium hydroxide solution is added so that the degree of Na neutralization is 70 mol% with respect to the carboxyl group, and after immersion at 90 ° C. for 2 hours, it is washed with water and dehydrated. And air-dried for 24 hours. The neutralized sample is dried with a hot air dryer at 105 ° C. for 16 hours and weighed (W1 g). Next, the sample is placed in a thermo-hygrostat adjusted to 20 ° C. × 65% RH for 24 hours. The weight of the sample thus absorbed is measured (W2 g).
(Saturated moisture absorption%) = (W2-W1) / W1 × 100

(3) About 1.0 g of a dyeable sample and 2.0 g of ordinary 3.3 dtex acrylonitrile fiber (Nippon Exlan Industry Co., Ltd. Exlan K8-3.3T) with respect to the total fiber weight (3.0 g) Immerse it in 300 mL of an aqueous solution of 200% (2.5% by weight) Nicholon Black G and acetic acid (2% by weight), boil it for 30 minutes, and then soak it in 300 mL of an aqueous solution of hydrosulfite 2 g / L at 60 ° C. for 15 minutes. Then, rinse with running water for 5 minutes and air dry. Acrylonitrile fiber is removed from the dyed fiber, and the obtained sample is visually evaluated for dyeability based on the following criteria.
○: Fully dyeable △: Lightly dyeable ×: Almost not dyed or abnormal hue

(4) Hue (standard color development)
About 1.0 g of the sample obtained in the above (3) was measured. The evaluation device uses a multi-light source spectrocolorimeter MSC-5 (C light source, 2-degree field of view) manufactured by Suga Test Instruments Co., Ltd., and is a screw-in cylindrical type having a bottom surface made of quartz glass and having a diameter of 40 mm. The bottom surface fixed to the cell was measured with a measurement hole having a diameter of 30 mm, and L *, a *, and b * values of the L * a * b * color system were calculated according to a conventional method. The lower the value of L *, the darker, that is, the higher the color developability. It shows that it becomes a hue different from black, so that the value of a * and b * leaves | separates from zero.

(5) About 0.25 g of a fiber sample obtained by drying the amount of sulfonic acid group of acrylonitrile fiber was precisely weighed (Sg) and dissolved in 20 mL of DMF. Next, 10 mL of Amberlite IR-120B (Rohm and Haas Co., Ltd., strongly acidic cation exchange resin) was added, stirred for 15 minutes, and filtered. DMF was added to dilute the filtrate to 50 mL, and conductivity titration was performed with a 0.0075 mol / L sodium hydroxide ethanol solution to obtain a titration curve. The consumption amount (VmL) of sodium hydroxide consumed by the sulfonic acid group was determined from the titration curve, and the sulfonic acid group amount (mmol / g) was calculated by the following formula.
(Amount of sulfonic acid group) = 0.0075 V / S

Production of Acrylonitrile Polymers A to C Monomers having the composition shown in Table 1 were subjected to continuous aqueous suspension polymerization with a redox catalyst of sodium chlorate / sodium pyrosulfite to prepare acrylonitrile polymers A to C.
The abbreviations in the table indicate AN: acrylonitrile, MA: methyl acrylate, SMAS: sodium metasulfonate, and VAc: vinyl acetate. The amount of sulfonic acid groups of the polymer is also shown.

Production of sulfonic acid group-containing resin D 48% by weight of acrylonitrile, 22% by weight of acrylic acid methyl ester, and 30% by weight of sodium styrene sulfonate as a sulfonic acid group-containing monomer are used as a redox catalyst of ammonium persulfite / sodium pyrosulfite. Continuous polymerization was performed to obtain a translucent latex containing 1.46 mmol / g of sulfonic acid groups.

Example 1
A spinning stock solution in which 10 parts of acrylonitrile polymer A is dissolved in 90 parts of a 48% sodium rhodanoate aqueous solution is spun and stretched in accordance with a conventional method, then dried and wet heat treated, and an AN system having a single fiber fineness of 1.0 dtex. Fiber was obtained. The AN fiber was subjected to crosslinking / hydrolysis treatment at 95 ° C. for 2 hours in an aqueous solution containing 0.5% hydrazine hydrate and 1.5% sodium hydroxide, and washed with water. Subsequently, it was heat treated in water at 120 ° C. for 1 hour, and then washed with a 3% nitric acid aqueous solution. The treated fiber was washed with water, applied with a spinning oil, dehydrated and dried to obtain a hygroscopic fiber of Example 1. Table 2 shows the evaluation results of the obtained fibers. In addition, the adhesion amount of the oil agent was adjusted to 0.5% by weight with respect to the fiber.

Comparative Example 1
A spinning stock solution in which 10 parts of acrylonitrile polymer B is dissolved in 90 parts of a 48% sodium rhodanate aqueous solution is spun and stretched according to a conventional method, and then dried and wet heat treated, and then an AN system having a single fiber fineness of 1.0 dtex. Fiber was obtained. The AN fiber was subjected to crosslinking / hydrolysis treatment at 95 ° C. for 2 hours in an aqueous solution containing 0.5% hydrazine hydrate and 2.0% sodium hydroxide, and washed with water. Subsequently, it was heat treated in water at 120 ° C. for 1 hour, and then washed with a 3% nitric acid aqueous solution. The treated fiber was washed with water, applied with a spinning oil, dehydrated and dried to obtain a hygroscopic fiber of Comparative Example 1. Table 2 shows the evaluation results of the obtained fibers.

Example 2
The AN fiber obtained in Comparative Example 1 was subjected to crosslinking and hydrolysis treatment at 95 ° C. for 2 hours in an aqueous solution containing 0.5% hydrazine hydrate and 1.5% sodium hydroxide, and washed with water. Subsequently, it was heat treated in water at 120 ° C. for 1 hour, and then washed with a 3% nitric acid aqueous solution. The treated fiber was washed with water, applied with a spinning oil, dehydrated and dried to obtain a hygroscopic fiber of Example 2. Table 2 shows the evaluation results of the obtained fibers.

Comparative Example 2
The AN fiber obtained in Comparative Example 1 was subjected to crosslinking and hydrolysis treatment at 95 ° C. for 2 hours in an aqueous solution containing 0.5% hydrazine hydrate and 1.5% sodium hydroxide, and washed with water. Washed with an aqueous solution of 3% nitric acid. The treated fiber was washed with water, applied with a spinning oil, dehydrated and dried to obtain a hygroscopic fiber of Comparative Example 2. Table 2 shows the evaluation results of the obtained fibers.

Comparative Example 3
The AN fiber obtained in Comparative Example 1 was subjected to crosslinking introduction treatment at 98 ° C. for 3 hours in a 20% aqueous solution of hydrazine hydrate and washed with water. Next, it was acid-treated at 90 ° C. for 2 hours in a 3% nitric acid aqueous solution and washed with water. Subsequently, hydrolysis was performed at 90 ° C. for 2 hours in a 3% aqueous solution of sodium hydroxide and washed with water. Subsequently, it was washed with an aqueous nitric acid solution having a pH of 2. The treated fiber was washed with water, applied with a spinning oil, dehydrated and dried to obtain a hygroscopic fiber of Comparative Example 3. Table 2 shows the evaluation results of the obtained fibers.

Example 3
10 parts of acrylonitrile polymer B was dissolved in 90 parts of a 48% aqueous sodium rhodate solution to prepare a spinning dope. A sulfonic acid group-containing resin D was added to the spinning stock solution so as to have the ratio shown in Table 3, mixed and dissolved to continuously prepare a mixed stock solution, which was led to a spinning device. Next, the mixed stock solution led to the spinning device was spun and drawn according to a conventional method, and then dried and wet-heat treated to obtain AN fibers having a single fiber fineness of 1.0 dtex. Using the AN fiber, a hygroscopic fiber of Example 3 was obtained according to the production method of Example 1. Table 3 shows the evaluation results of the obtained fibers.

Example 4
A spinning dope was prepared in the same manner as in Example 3 except that the ratio of the acrylonitrile polymer B and the sulfonic acid group-containing resin D was changed to obtain AN fibers having a single fiber fineness of 1.0 dtex. Using the AN fiber, a hygroscopic fiber of Example 4 was obtained according to the production method of Example 1. Table 3 shows the evaluation results of the obtained fibers.

Example 5
A spinning stock solution Qb was prepared by dissolving 12 parts of acrylonitrile polymer B in 88 parts of a 48% aqueous sodium rhodate solution so that the polymer concentration was 12% by weight. The spinning solution Qb had a viscosity of 3900 mPa · s at 30 ° C. Separately, 12 parts of the acrylonitrile polymer C12 shown below was dissolved in 88 parts of a 48% sodium rhodanate aqueous solution so that the polymer concentration was 12% by weight to prepare a spinning dope Qc. The spinning stock solution Qc had a viscosity at 30 ° C. of 4000 mPa · s.
Next, using a spinning device of a three-layer laminated structure formation type described in Japanese Patent Application Laid-Open No. 2000-45126, the two spinning stock solutions are mixed at a ratio of 1: 1 through a spinning stock solution distribution layer and a spinneret to form a Qb layer- It was led to become Qc layer-Qb layer, then spun in accordance with a conventional method, drawn, dried, and wet heat treated to obtain an AN fiber having a single fiber fineness of 1.0 dtex. Using the AN fiber, a hygroscopic fiber of Example 5 was obtained according to the production method of Example 1. Table 3 shows the evaluation results of the obtained fibers.

As can be seen from Tables 2 and 3, in Examples 1, 3 to 5, hygroscopic fibers capable of obtaining sufficient color developability by dyeing were obtained. In Comparative Example 1 using acrylonitrile-based polymer B having a sulfonic acid group amount of 0.05 mmol / g or less, it was hardly dyed, but in Example 2 where treatment was performed to increase the area of acrylonitrile-based polymer. Although the saturated moisture absorption rate was decreased, dyeing at a practical level was possible. Further, Comparative Example 2 prepared by the same method as Example 2 can hardly be dyed except that it is not subjected to hydrothermal treatment after crosslinking and hydrolysis. In Comparative Example 3, a high saturated moisture absorption rate is obtained. The color of the dyed fiber showed a green color different from the intended color, was unsuitable for practical dyeing, and could not be called a cationic dye-dyeable hygroscopic fiber.

Claims

A hygroscopic fiber obtained by crosslinking and hydrolyzing an acrylonitrile fiber having a sulfonic acid group of 0.03 mmol / g or more with respect to the fiber weight, wherein the fiber has a carboxyl group and a crosslinked structure. Cationic dye-dyeable hygroscopic fiber, characterized in that it comprises an area of a polymer and an area of an acrylonitrile polymer having a sulfonic acid group, and the area of the acrylonitrile polymer is 20 to 80% .
The color of the fiber after dyeing with a cationic dye as defined below is such that the L * in the L * a * b * color system (JIS-Z8729) is +45 or less, a * is −5 or more and +5 or less, and b * is −5. The cationic dye-dyeable hygroscopic fiber according to claim 1, wherein the fiber is +5 or less.
Color of fiber after dyeing with cationic dye: 1 g of hygroscopic fiber, 3.3 dtex, and 2 g of acrylonitrile fiber with a saturated dyeing amount of 1.8 g of Malacite Green, with respect to the total fiber weight (3 g) (2.5% by weight) and an acetic acid (2% by weight) aqueous solution for 30 minutes, then immersed in an aqueous solution of hydrosulfite 2 g / L for 15 minutes at 60 ° C., then washed with running water for 5 minutes and then air-dried And dyed hygroscopic fibers by removing the acrylonitrile fibers. Hue when the dyed hygroscopic fibers are opened, packed in a cylindrical cell having a quartz glass surface at the bottom, and measured using a spectrocolorimeter.
Acrylonitrile fiber 90 to 99% by weight of acrylonitrile polymer containing 80% by weight or more of acrylonitrile and 1 to 10% by weight of acrylic sulfonic acid group-containing resin 10% to 70% by weight of acrylonitrile %. The cationic dye-dyeable hygroscopic fiber according to claim 1, wherein the fiber is composed of a polymer.
The acrylonitrile fiber is composed of at least two acrylonitrile polymers having different acrylonitrile contents, and the difference in the contents is 2% by weight or more. Cationic dye dyeable hygroscopic fibers.
The method for producing a dye-dyeable hygroscopic fiber according to any one of claims 1 to 4, wherein the acrylonitrile fiber is crosslinked, hydrolyzed, and further subjected to heat treatment.