JPWO2011010590A1 - Acid dye-dyeable hygroscopic fiber and method for producing the same - Google Patents

Abstract

Conventional cross-linked acrylic fiber has features such as pH buffering, antistatic properties, water retention, etc. However, there was still a problem with dyeability. The present invention is a fiber having the above-described characteristics and having both practical dyeability with an acid dye, and specifically, a polymer having a functional group serving as an acid dye dyeing seat. And a region of a polymer having a crosslinked structure and a carboxyl group, and the saturated dyeing amount of the acidic dye with respect to the fiber weight is 3.5 to 10% by weight, and the carboxyl group amount is 1.0 to 10 mmol. / G is an acid dye dyeable hygroscopic fiber.

Description

The present invention relates to a fiber that can be dyed with an acid dye and has a hygroscopic property, and a method for producing the same.

Crosslinked acrylic acid fibers are known to have 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 / humidity control functions derived therefrom. It is used in the clothing and industrial materials fields. However, the cross-linked acrylic fiber has a problem in its dyeability, and is a factor that hinders application development.

Since the crosslinked acrylic fiber has a carboxyl group that functions as a dyeing seat for the cationic dye, in principle, it can be colored using a cationic dye. However, since the ionic bond formed between the cationic dye and the carboxyl group is weak, the cationic dye is likely to be liberated due to changes in pH, etc. In addition, the water swellability of the fiber is high, so that the free cationic The dye is easily eluted. For this reason, the dyeing fastness of the level which can be practically used cannot be obtained only by dyeing with a normal prescription.

In order to solve such problems relating to dyeability, Patent Documents 1 and 2 propose a method for dyeing crosslinked acrylic acid fibers with a reactive dye. In these methods, although the fastness to dyeing is improved by using reactive dyes, it is necessary to make the pH during dyeing strong acidic conditions, and it is necessary to deal with facilities such as restrictions on mixed fibers and countermeasures against corrosion. There is. In addition, when dyeing a fiber structure mixed with cellulosic fibers, there are cases in which the hue of the cellulosic fibers differs, and there is difficulty in practical color matching.

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. Since this fiber has a large amount of sulfonic acid groups that function as a dyeing seat for cationic dyes, it can be colored with cationic dyes, but it is not possible to obtain sufficient color development or dyeing fastness or hue stability. It was difficult. 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, the conventional cross-linked acrylic fiber has a harmonious function such as pH buffering property, antistatic property, water retention, high moisture absorption rate, high moisture absorption rate, high moisture absorption rate difference or temperature control / humidity control derived therefrom. Although it had features such as functions, it left a problem regarding dyeability. The present invention has been made based on the current situation, and provides a fiber capable of practical dyeing with an acid dye while maintaining the characteristics of the crosslinked acrylic acid fiber such as high hygroscopicity and high moisture absorption difference. For the purpose.

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

(1) A fiber composed of a polymer region having a functional group serving as an acid dye dyeing seat, a cross-linked structure, and a polymer region having a carboxyl group,
And the acid dye dyeable hygroscopic fiber whose saturation dyeing amount of the acid dye with respect to fiber weight is 3.5 to 10 weight% and whose carboxyl group amount is 1.0 to 10 mmol / g.
(2) The polymer having a functional group serving as an acid dye dyeing seat is a polymer having acrylonitrile as a main component and at least a vinyl monomer having a cationic group as a copolymerization component. The acid dye-dyeable hygroscopic fiber according to (1).
(3) A polymer having a functional group serving as an acid dye dyeing seat is obtained by treating a polymer mainly composed of acrylonitrile with a nitrogen-containing compound having two or more nitrogen atoms in one molecule. The acid dye-dyeable hygroscopic fiber as described in (1), which is a thing.
(4) A polymer having a crosslinked structure and a carboxyl group is obtained by subjecting a polymer mainly composed of acrylonitrile to a treatment with a nitrogen-containing compound having two or more nitrogen atoms in one molecule, and a hydrolysis treatment. The acid dye-dyeable hygroscopic fiber according to (1), which is characterized in that
(5) Nitrogen having two or more nitrogen atoms in one molecule with respect to the surface layer of the fiber composed of a polymer comprising acrylonitrile as a main component and at least a vinyl monomer having a cationic group as a copolymerization component The method for producing an acid dye-dyeable hygroscopic fiber according to (1), wherein a crosslinking treatment and a hydrolysis treatment are carried out with a contained compound.
(6) A method of performing a hydrolysis treatment after performing a crosslinking treatment with a nitrogen-containing compound having two or more nitrogen atoms in one molecule on a fiber composed of a polymer mainly composed of acrylonitrile, The method for producing an acid dye-dyeable hygroscopic fiber according to (1), wherein the hydrolysis treatment range is smaller than the crosslinking treatment range.

The acid dye-dyeable and hygroscopic fiber of the present invention is composed of a polymer region having a functional group serving as an acid dye dyeing seat, and a polymer region having a crosslinked structure and a carboxyl group. This enables practical dyeing with acid dyes and high moisture absorption performance. For this reason, the acid dye-dyeable hygroscopic fiber of the present invention has little restrictions on color, and can be developed for applications that are difficult to develop with conventional crosslinked acrylic fibers, such as applications that place importance on color.

The present invention is described in detail below. The acid dye-dyeable hygroscopic fiber of the present invention is a fiber composed of a polymer region having a functional group serving as an acid dye dyeing seat, and a polymer region having a crosslinked structure and a carboxyl group.

The area | region of the polymer which has a crosslinked structure and a carboxyl group in the acid dye dyeable hygroscopic fiber of this invention is a part mainly responsible for the hygroscopic performance which is one of the big characteristics of this fiber. As described above, the carboxyl group present in such a region can be ion-bonded with the cationic dye, but since it is easily ion-exchanged, the dyeing fastness is poor and practical level dyeing cannot be performed. In the fiber of the present invention, in addition to the above region, by providing a region of a polymer having a functional group that serves as an acid dye dyeing seat, it is possible to dye a practical level with an acid dye. Yes.

Examples of the polymer having a functional group serving as an acid dye dyeing seat include a polymer containing acrylonitrile as a main component and a vinyl monomer having at least a cationic group as a copolymerization component, and a polymer containing acrylonitrile as a main component. Examples thereof include those obtained by subjecting the coalescence to a treatment with a nitrogen-containing compound having two or more nitrogen atoms in one molecule. In the present invention, a polymer having acrylonitrile as a main component and at least a vinyl monomer having a cationic group as a copolymerization component is a polymer having a cationic group as an acrylonitrile-based polymer and acrylonitrile as a main component. The polymer is also referred to as an acrylonitrile polymer.

Here, the functional group serving as the acid dye dyeing seat is not particularly limited, and examples thereof include cationic groups such as a primary amino group, a secondary amino group, a tertiary amino group, and a quaternary ammonium group.

In addition, acrylonitrile as a main component means that the polymer contains 40 to 100% by weight of acrylonitrile in any of the above cases. There is no restriction | limiting in particular as a component of monomers other than acrylonitrile, (meth) acrylic acid ester compounds, such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, methallylsulfonic acid And sulfonic acid group-containing monomers such as p-styrene sulfonic acid and salts thereof; monomers such as styrene and vinyl acetate. Here, when a vinyl monomer having a cationic group is used as a copolymerization component, the cationic group of the monomer functions as a dyeing seat for acidic dyes.

Examples of the vinyl monomer having a cationic group include monomers represented by Chemical formula 1, Chemical formula 2 and Chemical formula 3. Here, in Chemical Formula 1, Chemical Formula 2 and Chemical Formula 3, R1 is hydrogen or a C4 or lower alkyl group, R2, R3 and R4 are each a C4 or lower alkyl group, R5 is a C4 or lower alkylene group or hydroxyalkylene group, R6 represents an alkylene group of C4 or less, X represents Cl, Br, I, CH ₃ COO, CH ₃ SO ₄ or SCN, m represents an integer of 2 to 4, and n represents an integer of 0 or 1.

Specific examples of these vinyl monomers having a cationic group include dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate.

In addition, when the acrylonitrile polymer is treated with a nitrogen-containing compound having two or more nitrogen atoms in one molecule, the nitrogen-containing compound and the nitrile group derived from acrylonitrile react to crosslink in the polymer. At this time, the functional group that did not react with the nitrile group or the functional group that had reacted with the nitrile group but did not form a cross-linked structure, became the acid dye dyeing seat. It is considered to function as a base.

The nitrogen-containing compound having two or more nitrogen atoms in one molecule is preferably an amino compound or a hydrazine compound having two or more primary amino groups. 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 polymer.

Examples of amino compounds having two or more primary amino groups include diamine compounds such as ethylenediamine and hexamethylenediamine, diethylenetriamine, 3,3′-iminobis (propylamine), N-methyl-3,3′-iminobis ( Triamine compounds such as propylamine), triethylenetetramine, N, N′-bis (3-aminopropyl) -1,3-propylenediamine, N, N′-bis (3-aminopropyl) -1,4- Examples include tetramine compounds such as butylenediamine, polyamine compounds having two or more primary amino groups such as polyvinylamine and polyallylamine.

Examples of the hydrazine compound include hydrazine hydrate, hydrazine sulfate, hydrazine hydrochloride, hydrazine hydrobromide, hydrazine carbonate, and the like.

On the other hand, examples of the polymer having a crosslinked structure and a carboxyl group include those obtained by subjecting an acrylonitrile-based polymer to treatment with a nitrogen-containing compound having two or more nitrogen atoms in one molecule and hydrolysis treatment. be able to. In the former treatment, a nitrogen-containing compound and a nitrile group derived from acrylonitrile are reacted to form a crosslinked structure in the polymer, and in the latter treatment, the nitrile group is hydrolyzed to form a carboxyl group. Thereby, the polymer which has a crosslinked structure and a carboxyl group is obtained.

Examples of the acrylonitrile-based polymer and the nitrogen-containing compound having two or more nitrogen atoms in one molecule include the same ones as described above. Moreover, about a hydrolysis process, alkaline metal salt compounds, such as an alkali metal hydroxide, an alkaline-earth metal hydroxide, and an alkali metal carbonate, can be used.

In addition, about the polymer which has a crosslinked structure illustrated here and a carboxyl group, it is 2 in 1 molecule in an acrylonitrile-type polymer similarly to the polymer illustrated as a polymer which has a functional group used as an acidic dye dyeing | staining seat. Although treatment with a nitrogen-containing compound having at least one nitrogen atom is performed, practical dyeing with an acid dye is not possible. This is thought to be because the functional group that once becomes the acid dye dyeing seat is formed by the cross-linking treatment, but the functional group is changed by the subsequent hydrolysis treatment, so that it does not function as the acid dye dyeing seat. .

Further, the acid dye-dyeable hygroscopic fiber of the present invention may be composed only of the above-described polymer region having a functional group that becomes an acid dye-dyed seat and a polymer region having a crosslinked structure and a carboxyl group. In addition to these regions, there may be a region in which the polymers constituting these regions are mixed, or a region composed of a polymer different from the polymer constituting these regions. As a typical example of the arrangement of these regions, a core sheath having a polymer region having a functional group serving as an acid dye dyeing seat as a central portion and a polymer region having a crosslinked structure and a carboxyl group as a surface layer portion. Structure, multi-layer structure in which a polymer region having a functional group serving as an acid dye dyeing seat and a cross-linking structure and a polymer region having a carboxyl group are alternately laminated, or a functional group serving as an acid dye dyeing seat Examples thereof include a sea-island structure in which one of a polymer region, a crosslinked structure, and a polymer region having a carboxyl group is a sea portion and the other is an island portion.

Regarding the ratio of the polymer region having a functional group that becomes an acid dye dyeing seat and the ratio of the crosslinked region and the polymer region having a carboxyl group, the higher the proportion of the crosslinked region and the polymer region having a carboxyl group, the higher the moisture absorption rate. In the meantime, the ratio of the polymer region having a functional group that becomes an acid dye dyeing seat is lowered, and the color developability tends to be lowered. In order to obtain a fiber in which both hygroscopicity and color developability are balanced, a functional group serving as an acid dye dyeing seat is formed in an area of 20 to 80%, more preferably 30 to 70% of the fiber cross-sectional area in a dry state. It is desirable to occupy the area of the polymer that it has.

Here, the above-mentioned area ratio can be calculated by cutting the dried fiber and observing the fiber cross section with an optical microscope after dyeing with an acid dye. That is, the dyed region is a region of a polymer having a functional group that becomes an acid dye dyeing seat, and the region that is not dyed or cannot be confirmed is a region of a polymer having a crosslinked structure and a carboxyl group.

In addition, the carboxyl group amount in the present invention is preferably 1.0 to 10 mmol / g, more preferably 2.0 to 6.0 mmol / g, based on the fiber weight. When the carboxyl group amount is less than 1.0 mmol / g, sufficient moisture absorption performance may not be obtained. When the carboxyl group amount exceeds 10 mmol / g, the crosslinked region and the polymer region having a carboxyl group may absorb moisture or absorb water. It may become fragile, causing the polymer to fall off, and failing to maintain the fiber shape and moisture absorption performance.

Further, the carboxyl group may be an H-type carboxyl group or a salt-type carboxyl group, and they may be mixed, but at the stage after fiber production, processing such as spinning is facilitated. Therefore, it is desirable to use H-type carboxyl groups, and after dyeing or at the final product stage, in order to obtain a high moisture absorption rate, it is desirable that 50% or more of the carboxyl group amount be salt-type carboxyl groups.

Examples of the cation constituting such a salt-type carboxyl group include alkali metals such as Li, Na and K, alkaline earth metals such as Be, Mg, Ca and Ba, Cu, Zn, Al, Mn, Ag and Fe. , Metals such as Co and Ni, cations such as NH ₄ and amines, and a plurality of types of cations may be mixed.

The saturated dyeing amount of the acid dye in the present invention is preferably 3.5 to 10% by weight, more preferably 4 to 9% by weight, based on the fiber weight. When the saturated dyeing amount is less than 3.5%, it cannot be dyed darkly and may not be suitable for practical use. When it exceeds 10%, the dyeing speed increases and uneven dyeing occurs. It becomes easy to cause. The saturated dyeing amount is determined by the method described later.

In addition, the acid dye-dyeable hygroscopic fiber of the present invention has improved fastness to dyeing compared to conventional cross-linked acrylic fiber, and fastness to sweat dyeing evaluated by the evaluation method described below. It is desirable that is a grade 3 or higher.
(Evaluation method) The sample was put into a bath containing 5% by weight of the acid dye, Suplanol Black VLG (manufactured by DyStar), adjusted to pH 4 with acetic acid, and then immersed at 100 ° C. for 30 minutes. After that, soaping, washing with water and drying are performed. About the obtained fiber, the fastness to sweat dyeing according to JIS-L-0848 is evaluated.

The saturated moisture absorption rate of the acid dye-dyeable hygroscopic fiber of the present invention at a temperature of 20 ° C. and a relative humidity of 65% is not generally determined because the required moisture absorption rate varies depending on the application, but is 15% by weight. % Or more is preferable, and more preferably 20% by weight or more.

Further, the acid dye-dyeable hygroscopic fiber of the present invention preferably has a degree of swelling of 2 g / g or less, more preferably 1.8 g / g or less. When the degree of swelling exceeds 2 g / g, the fiber physical properties may deteriorate or the operability may deteriorate.

Several methods can be mentioned as a manufacturing method of the acid dye dyeable hygroscopic fiber of this invention which has been mentioned above. For example, there can be mentioned a method in which an acrylonitrile fiber comprising an acrylonitrile polymer having a cationic group is used as a raw fiber, and the fiber is partially subjected to a crosslinking treatment and a hydrolysis treatment. In this method, a part of the acrylonitrile-based polymer having a cationic group is converted into a polymer region having a crosslinked structure and a carboxyl group by a crosslinking treatment and a hydrolysis treatment, and an unconverted portion is dyed with an acid dye. It becomes the area | region of the polymer which has a functional group used as a seat.

Here, the acrylonitrile fiber composed of an acrylonitrile polymer having a cationic group has a cationic group of 0.15 mmol / g or more, preferably 0.17 mmol / g or more based on the fiber weight. Is desirable. When the cationic group is less than 0.15 mmol / g, it may be necessary to reduce the area of the polymer having a crosslinked structure and a carboxyl group in order to obtain sufficient color developability. In addition, although there is no restriction | limiting in particular about an upper limit, From a viewpoint of the uniformity of dyeing | staining, it is desirable that it is 0.40 mmol / g or less.

Also, using acrylonitrile fiber made of acrylonitrile polymer as a raw fiber, the fiber is subjected to a crosslinking treatment with a nitrogen-containing compound having two or more nitrogen atoms in one molecule, followed by a hydrolysis treatment. It is a method, Comprising: The method of making the range which performs the said hydrolysis process smaller than the range which performs the said crosslinking process is also employable. In such a method, first, a region comprising a polymer having a functional group that becomes an acid dye dyeing seat together with a crosslinked structure is formed by a crosslinking treatment, and a portion of the region is then converted into a carboxylated structure and a carboxyl by hydrolysis treatment thereafter. It is converted into a polymer region having groups. In this method, it goes without saying that an acrylonitrile polymer having a cationic group may be used as the acrylonitrile polymer.

Further, acrylonitrile fiber made of acrylonitrile-based polymer having no functional group serving as an acid dye dyeing seat is used as a raw material fiber, and after partially introducing a functional group serving as an acid dye dyeing seat into this, a crosslinking treatment and A method of performing a hydrolysis treatment, or an acrylonitrile fiber containing a polymer having a functional group serving as an acid dye dyeing seat other than an acrylonitrile polymer is used as a raw fiber, and this is partially subjected to a crosslinking treatment and a hydrolysis treatment. An application method can also be employed.

In the above-described production methods, the ratio of the acrylonitrile polymer in the acrylonitrile fiber used as the raw fiber is 80 to 100% by weight regardless of the presence or absence of the functional group serving as the acid dye dyeing seat. It is desirable.

Moreover, it is also preferable that the acrylonitrile fiber used as the raw 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 is generated, and a polymer region having a functional group that becomes an acid dye dyeing seat and a polymer region having a crosslinked structure and a carboxyl group are easily formed.

Such an acrylonitrile fiber may be one obtained by bonding two kinds of acrylonitrile polymers side-by-side or 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 cationic groups. Specifically, it is desirable that the acrylonitrile content in the B layer or the core portion is 82% by weight or more, preferably 85% by weight or more, more preferably 90% by weight or more, and the content of the cationic group is 0.00. It is desirable that it is 15 mmol / g or more, preferably 0.17 mmol / g or more.

In addition, as a method for obtaining an acrylonitrile fiber having a three-layer structure composed of an A-B-A layer, a method described in JP-A 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.

As the method for producing the acid dye-dyeable hygroscopic fiber of the present invention described above, the acrylonitrile-based fiber composed of an acrylotolyl-based polymer having a cationic group contains nitrogen having two or more nitrogen atoms in one molecule. After crosslinking with a compound, hydrolysis treatment with an alkaline metal salt aqueous solution, or by performing these treatments simultaneously, a polymer region having a crosslinked structure and a carboxyl group is formed on the surface layer of the fiber, and the core portion A method of leaving an area of an acrylonitrile-based polymer having a cationic group is desirable from the viewpoint of manufacturing equipment and cost. This method will be described in detail below.

In such a method, the above-described crosslinking introduction treatment with an aqueous solution containing a nitrogen-containing compound having two or more nitrogen atoms in one molecule is added to the acrylonitrile-based fiber composed of the above-described acrylonitrile-based polymer having a cationic group and alkaline. A hydrolysis treatment with an aqueous solution containing a metal salt compound is performed. These treatments can be carried out by individual treatments in which a hydrolysis treatment is performed after the crosslinking treatment, or simultaneously using 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. It can also be done by processing. In any case, a crosslinked structure is formed by the reaction of the nitrogen-containing compound having two or more nitrogen atoms in one molecule with the nitrile group of the acrylonitrile polymer in the surface layer portion of the acrylonitrile fiber, and an alkaline metal salt. A carboxyl group is formed by the reaction between the compound aqueous solution and the nitrile group, which is converted into a polymer having a crosslinked structure and a carboxyl group.

As a specific method for the crosslinking treatment and the hydrolysis treatment, a method of reacting fibers in an aqueous solution used for the treatment can be employed. In either case of individual treatment or 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%. ~ 3 wt%. If this concentration is too low, the effect of suppressing elution of the polymer having a crosslinked structure and a carboxyl group may not be obtained. On the other hand, in order to stop the introduction of the crosslinked structure at the surface layer portion of the fiber, it is desirable that the concentration be 5% by weight or less. Moreover, about the density | concentration of an alkaline metal salt compound, Preferably it is 0.5 to 5 weight%, More preferably, it is 0.5 to 4 weight%. If the concentration of the alkaline metal salt compound is too low, the amount of carboxyl groups produced may be insufficient. On the other hand, by suppressing this concentration to 5% by weight or less, introduction of carboxyl groups can be stopped at the surface layer portion of the fiber, leaving an area of the acrylonitrile polymer having a cationic group at the core portion.

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.

In the case of the above individual treatment, the fiber subjected to the crosslinking 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 soaking the treated fiber 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. However, this acid treatment has an effect of proceeding hydrolysis and reducing the area of the acrylonitrile-based polymer to be left in the finally obtained fiber, that is, the polymer having a functional group that becomes an acid dye dyeing seat, It is important to set conditions in consideration of this.

The fiber after hydrolysis or simultaneous crosslinking and hydrolysis treatment obtained as described above can be used as it is as the dye-dyeable hygroscopic fiber of the present invention, but may be further washed with an acidic aqueous solution. Thereby, a fiber with higher whiteness can be obtained. Examples of the acidic aqueous solution include, but are not particularly limited to, an aqueous solution of a mineral acid such as nitric acid, sulfuric acid, and hydrochloric acid, and an organic acid.

Further, as described above, at the stage after fiber production, an H-type carboxyl group is used for easy processing such as spinning, and after dyeing or at the final product stage, the desired salt-type carboxyl group or H-type carboxyl group is obtained. It is desirable to convert or to mix different salt types. Such adjustment of the carboxyl group type can be carried out by performing ion exchange treatment with a metal salt such as nitrate, sulfate or hydrochloride, pH adjustment treatment with a buffer solution or the like. In order to obtain a high moisture absorption rate, it is desirable that 50% or more of the carboxyl group amount is a salt-type carboxyl group.

Moreover, after using the acrylonitrile-based fiber made of the acrylonitrile-based polymer described above as a raw fiber, the fiber is subjected to a crosslinking treatment with a nitrogen-containing compound having two or more nitrogen atoms in one molecule, followed by a hydrolysis treatment It is also a preferred method to make the range for the hydrolysis treatment smaller than the range for the crosslinking treatment. In such a method, in order to make the range for the crosslinking treatment wider than the range for the hydrolysis, the crosslinking treatment is first performed with a solution in which the concentration of the nitrogen-containing compound having two or more nitrogen atoms in one molecule is set high. And then hydrolyzed. For example, in the case of a core-sheath structure, the concentration of the nitrogen-containing compound is preferably 7 to 20% by weight, more preferably 10 to 20% by weight, because the entire fiber is subjected to a crosslinking treatment. About the conditions of the hydrolysis process of the fiber surface layer part after this process, what is necessary is just to employ | adopt the conditions mentioned above, and what is necessary is just to perform the acid treatment and the adjustment of the type of a carboxyl group as needed.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. In addition, unless otherwise indicated, the part and percentage in an Example are shown on a weight basis. The evaluation methods of the characteristics in the examples are as follows.

(1) About 1 g of a sufficiently dried sample of carboxyl groups (A [g]) was added, 200 ml of water was added thereto, and then a 1 mol / L hydrochloric acid aqueous solution was added while heating to 50 ° C. Then, a titration curve is obtained with a 0.1 mol / L aqueous sodium hydroxide solution according to a conventional method. The consumption amount (B [ml]) of an aqueous sodium hydroxide solution consumed by carboxyl groups is determined from the titration curve, and the carboxyl group amount is calculated by the following formula.
Amount of carboxyl group [mmol / g] = 0.1 × B / A

(2) About 0.5 g of a sufficiently dried sample of the basic fiber of the raw fiber (C [g]) is precisely weighed (C [g]), and a 0.1 mol / L hydrochloric acid aqueous solution (D [ml]) in an amount sufficient for ion exchange. Immerse in a beaker containing. The sample is filtered and a phenolphthalein solution is added to the filtrate as an indicator. The filtrate was titrated with a 0.1 mmol / L aqueous sodium hydroxide solution to quantify residual hydrochloric acid. The amount of the cationic group was calculated according to the following equation with the titration amount of the aqueous sodium hydroxide solution at that time as E [ml].
Cationic group amount [mmol / g] = (0.1 × D−0.1 × E) / C

(3) About 5.0 g of saturated moisture absorption sample was immersed in water, an aqueous sodium hydroxide solution was added so that the neutralization degree was 70% with respect to the carboxyl group, and after immersion treatment at 70 ° C. for 1 hour, Wash with water, dehydrate, and air dry for 24 hours. The neutralized sample is dried with a hot air dryer at 105 ° C. for 16 hours, and the weight is measured (F [g]). Next, the sample is placed in a thermo-hygrostat adjusted to 20 ° C. and a relative humidity of 65% for 24 hours. The weight of the sample thus absorbed is measured. (G [g]). From the above measurement results, calculation is performed according to the following equation.
Saturated moisture absorption [%] = (G−F) / F × 100

(4) Swelling degree About 3 g of the sample is dried with a hot air dryer at 70 ° C. for 3 hours and the weight is measured (H [g]). Next, after immersing the sample in a beaker containing 300 ml of water for 30 minutes, the swollen sample is dehydrated with a desktop centrifugal dehydrator (160 G × 5 minutes), and the weight of the sample is measured (J [g]). From the above measurement results, calculation is performed according to the following equation.
Swelling degree [g / g] = (J−H) / H

(5) The dyeable sample was put into a bath containing 5% of the acid dye Supranol Black VLG (manufactured by DyStar) with respect to the weight of the sample, adjusted to pH 3.5 with acetic acid, and then adjusted to 30 at 100 ° C. After soaking for a minute, soaping, washing and drying are performed. The obtained fiber is visually evaluated for dyeability based on the following criteria.
○: Fully dyeable △: Lightly dyeable ×: Almost not dyed or abnormal hue

(6) Fastness of sweat dyeing The fastness of sweat dyeing according to JIS-L-0848 is evaluated for fibers dyed by the same method as “(5) Dyeability”.

(7) The cross-sectional area ratio of the region of the acrylonitrile-based polymer is calculated by cutting the fiber dyed by the same method as “(5) Dyeability” and observing the fiber cross section with an optical microscope.

(8) Saturated dyeing amount A dye mother liquor containing 20% acidic dye Sandolan Fast Blue P-L 125% (manufactured by Sandoz) and adjusted to pH 3 with acetic acid with respect to the weight of the sample to be charged is bath ratio 1: 200, and the absorbance of the stained mother liquor with respect to light having a wavelength of 590 nm is measured. Next, the sample is put into the stained mother liquor and treated at 100 ° C. for 30 minutes. After slow cooling, the dyeing bath is adjusted to pH 7 with sodium carbonate and treated at 70 ° C. for 30 minutes. Next, the water evaporated during the treatment is supplemented to the dyeing bath, the bath ratio is adjusted again to 1: 200, and the absorbance of the dyeing residual solution with respect to light having a wavelength of 590 nm is measured. From the above measurement results, the saturated dyeing amount relative to the fiber weight is calculated using the following formula.
Saturated dyeing amount (%) = (absorbance of stained mother liquor−absorbance of dyeing residual solution) / absorbance of stained mother liquor × 20
In addition, the light absorbency of dyeing | staining mother liquor and the dyeing | staining residual liquid was measured using U-1100 Spectrophotometer (made by Hitachi, Ltd.) after each 20 times dilution.

[Example 1]
10 parts of an acrylonitrile polymer (intrinsic viscosity [η] = 1.2 in dimethylformamide at 30 ° C.) consisting of 86% acrylonitrile, 11% methyl acrylate and 3% dimethylaminoethyl (meth) acrylate is 48% rhodasoda The spinning solution dissolved in 90 parts of the aqueous solution was spun and stretched according to a conventional method (total stretching ratio: 10 times), dried in an atmosphere of dry bulb / wet bulb = 120 ° C./60° C., and then subjected to wet heat treatment. A raw fiber (fiber length 51 mm) having a fiber fineness of 2.2 dtex was obtained. The raw fiber is treated at 90 ° C. for 2 hours in an aqueous solution containing 0.4% hydrazine hydrate and 2% sodium hydroxide, washed with an aqueous nitric acid solution having a pH of 2 or less, washed with water, and dried. The fiber of Example 1 was obtained. The evaluation results of the obtained fiber are shown in Table 1.

[Example 2]
The raw material fiber of Example 1 was treated at 90 ° C. for 1.5 hours in an aqueous solution containing 0.4% hydrazine hydrate and 2% sodium hydroxide, washed with an aqueous nitric acid solution having a pH of 2 or less, washed with water, The fiber of Example 2 was obtained by drying. The evaluation results of the obtained fiber are shown in Table 1.

[Example 3]
48% of 10 parts of acrylonitrile polymer (intrinsic viscosity [η] = 1.2 in 30 ° C. dimethylformamide) consisting of 90% acrylonitrile, 9.7% methyl acrylate and 0.3% sodium methallylsulfonate A spinning stock solution dissolved in 90 parts of an aqueous rhodium soda solution is spun and drawn according to a conventional method (total draw ratio: 10 times), then dried in an atmosphere of dry bulb / wet bulb = 120 ° C./60° C., and then wet-heat treated. A raw fiber (fiber length 51 mm) having a fiber fineness of 2.2 dtex was obtained. The raw fiber was treated at 110 ° C. for 1 hour in an aqueous solution containing 10% hydrazine hydrate, then treated at 100 ° C. for 1 hour with an aqueous solution containing 1.6% sodium hydroxide, and the pH was 2 or less. The fiber of Example 3 was obtained by washing with an aqueous nitric acid solution, washing with water and drying. The evaluation results of the obtained fiber are shown in Table 1.

[Example 4]
The raw material fiber of Example 1 was treated in an aqueous solution containing 15% hydrazine hydrate at 110 ° C. for 1.5 hours, and then treated with an aqueous solution containing 2% sodium hydroxide at 100 ° C. for 1 hour. The fiber of Example 4 was obtained by washing with an aqueous nitric acid solution having a pH of 2 or less, washing with water and drying. The evaluation results of the obtained fiber are shown in Table 1.

[Comparative Example 1]
The raw material fiber of Example 1 was treated at 110 ° C. for 3 hours in a 15% aqueous solution of hydrazine hydrate and washed. The obtained fiber was immersed in an 8% aqueous nitric acid solution and treated at 100 ° C. for 1 hour. Subsequently, a hygroscopic fiber of Comparative Example 1 was obtained by performing treatment in a 5% aqueous sodium hydroxide solution at 100 ° C. for 1 hour, washing with a nitric acid aqueous solution having a pH of 2 or less, washing with water, and drying. The evaluation results of the obtained fiber are shown in Table 1.

[Comparative Example 2]
In Example 1, the hygroscopic fiber of Comparative Example 2 was obtained in the same manner except that the raw material fiber of Example 3 was used as the raw material fiber. The evaluation results of the obtained fiber are shown in Table 1.

In Example 1, a fiber having good dyeability and fastness to dyeing with an acid dye and good moisture absorption performance was obtained. The hygroscopic fiber of Example 2 has a wider area of acrylonitrile polymer than the hygroscopic fiber of Example 1, but has sufficient hygroscopic performance as a hygroscopic fiber, and has good dyeability and fastness to dyeing. It was what had. In Example 3, the starting material is an acrylonitrile fiber made of an acrylonitrile polymer that does not have a functional group serving as an acid dye dyeing seat, but a hygroscopic fiber having good dyeability and dyeing fastness can be obtained. It was. This is considered to be due to the introduction of a functional group serving as an acid dye-dyed seat derived from the crosslinking agent in the fiber inner layer by strengthening the crosslinking treatment conditions. In Example 4, acrylonitrile fiber made of acrylonitrile-based polymer having a cationic group was used as a raw fiber, and the crosslinking treatment conditions were strengthened, so that there were many functional groups serving as an acid dye dyeing seat effective for dyeing. It is considered that a hygroscopic fiber having a high saturation dyeing amount was obtained.

On the other hand, the fiber of Comparative Example 1 has a low saturated dyeing amount, cannot be dyed to the intended hue, and has a low dyeing fastness. This is presumably because the hydrolysis treatment conditions were strengthened, so that hydrolysis occurred in the entire fiber and many of the cationic groups possessed by the raw fiber were lost. In addition, the functional group that becomes the acidic dye dyeing seat derived from the cross-linking agent also changes to another functional group by hydrolysis, or many carboxyl groups are formed by hydrolysis around the functional group, It is considered that the structure absorbs water easily and swells, and even if the dye is dyed, it does not function sufficiently as an acid dye dyeing seat because it comes into contact with water and easily flows out. Moreover, since the fiber of the comparative example 2 stopped the crosslinking process and the hydrolysis process only in the fiber surface layer part with respect to the raw material fiber which does not have a functional group used as an acid dye dyeing | seat seat, acid dye dyeing | staining is carried out to a core part. There is no functional group serving as a seat, and the surface layer portion has the same structure as that of the fiber of Comparative Example 1, which is considered to be inferior in dyeability. In addition, about the fiber of these comparative examples, since appropriate dyeing | staining cannot be performed, the cross-sectional area ratio of the area | region of an acrylonitrile-type polymer was not able to be calculated | required.

Since the acid dye-dyeable and hygroscopic fiber of the present invention has high hygroscopic performance and excellent dyeability with an acid dye, practical dyeing is possible. For this reason, it is possible to develop applications where the use of the conventional crosslinked acrylic fiber is restricted because practical dyeing is difficult.

[0002]
It has been proposed. Since this fiber has a large amount of sulfonic acid groups that function as a dyeing seat for cationic dyes, it can be colored with cationic dyes, but it is not possible to obtain sufficient color development or dyeing fastness or hue stability. It was difficult. 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.
Prior Art Literature Patent Literature [0006]
Patent Document 1: Japanese Patent Application Laid-Open No. 2003-278079 Patent Document 2: Japanese Patent Application Laid-Open No. 2006-70421 Patent Document 3: Japanese Patent Application Laid-Open No. 2008-174849 SUMMARY OF THE INVENTION Problems to be Solved by the Invention [0007]
As described above, the conventional cross-linked acrylic fiber has a harmonious function such as pH buffering property, antistatic property, water retention, high moisture absorption rate, high moisture absorption rate, high moisture absorption rate difference or temperature control / humidity control derived therefrom. Although it had features such as functions, it left a problem regarding dyeability. The present invention has been made based on the current situation, and provides a fiber capable of practical dyeing with an acid dye while maintaining the characteristics of the crosslinked acrylic acid fiber such as high hygroscopicity and high moisture absorption difference. For the purpose.
Means for Solving the Problems [0008]
As a result of diligent studies to achieve the above-mentioned object, the present inventors have reached the present invention shown below.
[0009]
(1) A fiber comprising a polymer region having a cross-linked structure and a carboxyl group, and a polymer region having a functional group serving as an acid dye dyeing seat, separate from the region,
And the acid dye dyeable hygroscopic fiber whose saturation dyeing amount of the acid dye with respect to fiber weight is 3.5 to 10 weight% and whose carboxyl group amount is 1.0 to 10 mmol / g.

Claims (6)

It is a fiber composed of a polymer region having a functional group serving as an acid dye dyeing seat and a polymer region having a crosslinked structure and a carboxyl group,
And the acid dye dyeable hygroscopic fiber whose saturation dyeing amount of the acid dye with respect to fiber weight is 3.5 to 10 weight% and whose carboxyl group amount is 1.0 to 10 mmol / g. 2. The polymer having a functional group serving as an acid dye dyeing seat is a polymer containing acrylonitrile as a main component and a vinyl monomer having at least a cationic group as a copolymerization component. Acid dye-dyeable hygroscopic fibers as described in 1. A polymer having a functional group serving as an acid dye dyeing seat is obtained by treating a polymer mainly composed of acrylonitrile with a nitrogen-containing compound having two or more nitrogen atoms in one molecule. The acid dye-dyeable hygroscopic fiber according to claim 1. A polymer having a crosslinked structure and a carboxyl group is obtained by subjecting a polymer containing acrylonitrile as a main component to a treatment with a nitrogen-containing compound having two or more nitrogen atoms in one molecule and a hydrolysis treatment. The acid dye-dyeable hygroscopic fiber according to claim 1, wherein the dye is hygroscopic. Due to a nitrogen-containing compound having two or more nitrogen atoms in one molecule with respect to the surface layer portion of the fiber composed of a polymer composed mainly of acrylonitrile and having a vinyl monomer having at least a cationic group as a copolymerization component The method for producing an acid dye-dyeable hygroscopic fiber according to claim 1, wherein a crosslinking treatment and a hydrolysis treatment are performed. A method comprising subjecting fibers made of a polymer mainly composed of acrylonitrile to a crosslinking treatment with a nitrogen-containing compound having two or more nitrogen atoms in one molecule, followed by a hydrolysis treatment, The method for producing an acid dye-dyeable hygroscopic fiber according to claim 1, wherein the hydrolysis treatment range is smaller than the application range.