TWI645086B - Crosslinking acrylate based fiber and fiber structure comprising the same - Google Patents

Abstract

Cross-linked acrylic fibers are well-known for their high hygroscopicity and are used in the field of clothing and industrial materials. However, since the fiber has the characteristics that the higher the hygroscopicity, the lower the bulkiness or the morphological stability, there is a problem that it is difficult to have both the high moisture absorption performance and the carding processability or bulkiness at the same time. An object of the present invention is to provide a hygroscopic fiber and a fiber structure containing the fiber which cannot be provided by the prior art. The hygroscopic fiber can have both hygroscopic and sweltering properties in the field of clothing and bedding. And can increase the bulkiness of the moisturizing property, and a good fiber web can be obtained in the carding step. The present invention provides a crosslinked acrylic fiber, which has a crosslinked structure, a carboxyl group of 2 mmol / g to 10 mmol / g, and a crimp ratio of 7% or more.

Description

Crosslinked acrylic fiber and fiber structure containing the same

The present invention relates to a cross-linked acrylic fiber having excellent characteristics such as bulkiness and entanglement, and excellent crimpability and high moisture absorption.

Cross-linked acrylic fibers are known to have functions such as pH buffering, antistatic properties, water retention, etc., as well as high hygroscopicity, high hygroscopic speed, poor hygroscopicity, or temperature regulation from them The humidity control function (for example, Patent Document 1 and Patent Document 2) can be used in the field of clothing or industrial materials.

However, the crosslinked acrylic fiber has a high moisture absorption rate, and therefore has characteristics of low bulkiness and low morphological stability. Therefore, it may be difficult to perform carding, and it may not be able to be developed for applications that require bulkiness such as padding. "Prior Art Literature" <Patent Literature>

<Patent Document 1> Patent Publication Hei 7-216730 <Patent Document 2> Patent Publication Hei 5-132858

"Questions to be Solved by Invention"

An object of the present invention is to provide a fiber having high moisture absorption and release properties and processability or bulkiness that cannot be provided by the prior art. Another object of the present invention is to provide a fibrous structure which is useful in the field of clothing and bedding, and which has both hygroscopic properties capable of reducing moisture absorption heat generation and sweltering feeling, and a bulkiness which improves moisture retention. "Solutions"

The above object of the present invention is achieved by the following means. (1) A crosslinked acrylic fiber, which has a crosslinked structure, a carboxyl group of 2 mmol / g to 10 mmol / g, and a shrinkage ratio of 7% or more. (2) The crosslinked acrylic fiber according to (1), wherein the amount of carboxyl group is 5 mmol / g to 10 mmol / g. (3) The crosslinked acrylic fiber according to (1) or (2), wherein the crimp ratio is 10% or more. (4) The crosslinked acrylic fiber according to any one of (1) to (3), which is a counter ion having a carboxyl group of a polyvalent metal ion. (5) The crosslinked acrylic fiber according to any one of (1) to (4), wherein a carboxyl group is present in all the fibers. (6) The cross-linked acrylic fiber according to any one of (1) to (5), wherein a nitrogen-containing compound having a nitrogen number of 2 or more in one molecule is used for acrylonitrile having two types Acrylonitrile fibers having a side-by-side structure formed of a polymer are obtained by performing a crosslinking treatment and a hydrolysis treatment. (7) A fiber structure containing the crosslinked acrylic fiber according to any one of (1) to (6). (8) A stuffing cotton containing the crosslinked acrylic fiber according to any one of (1) to (6). "Effects of Invention"

The cross-linked acrylic fiber system of the present invention has both high hygroscopicity and bulkiness, and can reduce the sweltering feeling caused by body fluids produced by the body, and can realize a comfortable temperature and humidity environment based on moisturizing property. In addition, it has entanglement property and can be easily made into a web in a carding step. The crosslinked acrylic fiber system of the present invention can be suitably used for padding of clothing, bedding, and the like.

Hereinafter, the present invention will be described in detail. The crosslinked acrylic fiber of the present invention is a fiber having a crosslinked structure, a carboxyl group of 2 mmol / g to 10 mmol / g, and a crimp ratio of 7% or more. The carboxyl group is the main factor that makes the cross-linked acrylic fiber exhibit characteristics such as moisture absorption and dehumidification, heat absorption and heat generation. Therefore, the fiber preferably contains 2 mmol / g to 10 mmol / g, and preferably 5 mmol / g A carboxyl group in a range of ~ 10 mmol / g, and more preferably 5 mmol / g to 8 mmol / g. When the amount of carboxyl group is reduced to 2 mmol / g, sufficient moisture absorption performance cannot be obtained in a fiber structure or the like mixed with other fibers. When the amount of the carboxyl group exceeds 10 mmol / g, it becomes fragile when absorbing moisture or water, and thus the fiber shape or hygroscopic performance cannot be maintained.

Regarding the shrinkage rate, it has been stipulated in JIS L1015. The higher the shrinkage rate, the easier it is for fibers and fibers to become entangled. Therefore, it becomes fluffy when made into fiber aggregates such as fiber webs, nonwovens, and woven yarns. The shrinkage ratio in the fiber of the present invention is preferably 7% or more, and more preferably 10% or more. When the shrinkage rate is reduced to 7%, the degree of connection between the fibers in the carding step becomes worse. In addition, when the fiber aggregate is made into a fiber aggregate, the bulkiness is also reduced, and it is mixed with other fibers. In the case of filled cotton, etc., a shape having a sufficient thickness cannot be obtained.

The bulkiness of the crosslinked acrylic fiber of the present invention is preferably 35 cm ³ / g or more in specific volume volume, which will be described later, in the case of use in a quilt or a stuffed cotton application. It is preferably at least 40 cm ³ / g.

In terms of the hygroscopic property of the crosslinked acrylic fiber of the present invention, among the fiber structures obtained by mixing with other fibers, from the viewpoint of obtaining a meaningful hygroscopic property with a practical mixing degree, The moisture absorption meter described later is preferably 20% or more, more preferably 25% or more, and even more preferably 35% or more. Although the upper limit of such a moisture absorption rate is not particularly limited, since the amount of carboxyl groups to be introduced is limited, the upper limit is approximately 70%.

The acrylonitrile-based fiber of the raw material fiber of the crosslinked acrylic fiber of the present invention can be produced from an acrylonitrile-based polymer by referring to a known method. The composition of the polymer is preferably 40% by weight or more, more preferably 50% by weight or more, and even more preferably 80% by weight or more. As described later, the crosslinked structure can be introduced into the fiber by reacting the nitrile group of the acrylonitrile-based copolymer used to form the acrylonitrile-based fiber with a nitrogen-containing compound such as a hydrazine-based compound. The crosslinked structure greatly affects the physical properties of the fiber. When the copolymerization composition of acrylonitrile is too small, although the cross-linked structure will inevitably be reduced, so that the physical properties of the fiber may become insufficient, however, by setting the copolymerization composition of acrylonitrile to the above Range, it becomes easy to get good results.

The copolymerization component other than acrylonitrile in the acrylonitrile-based polymer is not particularly limited as long as it is a monomer that can be copolymerized with acrylonitrile; specifically, for example, it may be methallyl Sulfonic acid group-containing monomers and salts thereof such as sulfonic acid, p-styrene sulfonic acid and the like; carboxylic acid group-containing monomers and salts thereof such as (meth) acrylic acid and itaconic acid; styrene, vinyl acetate, Monomers such as (meth) acrylate, (meth) acrylamide, and the like.

An effective method for obtaining a highly crimped cross-linked acrylic fiber is an acrylonitrile fiber based on a composite of two or more acrylonitrile polymers as a raw material fiber. For example, acrylonitrile-based fibers combined with two types of acrylonitrile-based polymers having different acrylonitrile polymerization ratios can be used as raw material fibers, which can cause cross-linking in various acrylonitrile-based polymers. The introduction amount of the structure is different, and the degree of shrinkage during the hydrolysis treatment is different, so that the shrinkage phenomenon can be found. The composite structure of acrylonitrile-based polymers may be formed by side-by-side joining or by random mixing. However, the acrylonitrile-based polymers are preferably joined side by side. Composite construction. In this case, the difference in the acrylonitrile polymerization ratio between the two types of acrylonitrile-based polymers is preferably 1% to 10%, and more preferably 1% to 5 in order to obtain a sufficient crimp ratio. %; The composite ratio of the two acrylonitrile polymers is preferably 20/80 to 80/20, and more preferably 30/70 to 70/30.

In addition, as for the form of the acrylonitrile-based fiber used in the present invention, any form of short fiber, silk, yarn, knitted fabric, non-woven fabric, etc. may be adopted, and intermediate products and waste fibers in the manufacturing process may also be used. .

As for the cross-linking agent for introducing the cross-linked structure into the acrylonitrile-based fiber, although any conventionally known cross-linking agent may be used, it is preferable from the viewpoints of the crosslinking reaction efficiency and ease of handling. To use nitrogen-containing compounds. Such a nitrogen-containing compound must have two or more nitrogen atoms in one molecule. The reason is that when the number of nitrogen atoms in one molecule is 2 or less, a crosslinking reaction does not occur. Specific examples of such nitrogen-containing compounds are not particularly limited as long as they are capable of forming a crosslinked structure, but preferred are amine compounds and hydrazine compounds having two or more primary amine groups. Examples of amine compounds having two or more primary amine groups, for example, they may be diamine compounds such as ethylenediamine, hexamethylenediamine; diethylene glycol, 3, 3'-iminobis (Propylamine), N-methyl-3, 3'-iminobis (propylamine), and other triamine compounds; triethylene ethylene tetramine, N, N'-bis (3-aminopropyl) -1 Tetraamine compounds such as 1,3-propanediamine, N, N'-bis (3-aminopropyl) -1,4-butanediamine; 2 of polyvinylamine, polyallylamine, etc. The above-mentioned primary amine-based polyamine compounds and the like. Examples of the hydrazine-based compound include, for example, hydrazine hydrogen, hydrazine sulfate, hydrazine hydrochloride, hydrazine hydrobromide, and hydrazine carbonate. In addition, although the upper limit of the number of nitrogen atoms in one molecule is not particularly limited, it 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-mentioned upper limit, the cross-linking agent molecule may become large and it may be difficult to introduce a cross-linked structure into the fiber.

The conditions for introducing the cross-linked structure are not particularly limited, and the reactivity between the used cross-linking agent and the acrylonitrile-based fiber, the amount of the cross-linked structure, the moisture absorption rate, the poor moisture absorption rate, and the fiber may be considered. The physical properties are appropriately selected. For example, in the case of using a hydrazine-based compound as a cross-linking agent, for example, it can be immersed in an aqueous solution prepared by adding the above-mentioned hydrazine-based compound to a hydrazine concentration of 3% to 40% by weight. Acrylonitrile-based fibers, and processed at 50 ° C to 120 ° C for less than 5 hours.

The fiber having a crosslinked structure can be subjected to a hydrolysis treatment with an alkali metal compound. Through this treatment, the nitrile group present in the fiber is hydrolyzed to form a carboxyl group. The specific processing conditions are various conditions in which the concentration of the processing agent, the reaction temperature, and the reaction time can be appropriately set in consideration of the amount of the carboxyl group. However, for industrial and fiber properties, the ideal method is: A means for treating 0.5 to 10% by weight, more preferably 1 to 5% by weight, of a treatment chemical solution at a temperature of 50 ° C to 120 ° C for 1 to 10 hours.

Here, the carboxyl group has a base-type carboxyl group whose counter ion is a cation other than a hydrogen ion, and an H-type carboxyl group whose counter ion is a hydrogen ion. Although the ratio can be arbitrarily adjusted, in order to obtain a high hygroscopicity, it is desirable that more than 40% of the carboxyl groups are base-type carboxyl groups.

The type of the cation constituting the base-type carboxyl group may be, for example, an alkali gold group metal such as lithium, sodium, potassium, etc., an alkaline earth group metal such as magnesium, calcium, manganese, copper, zinc, silver, or the like. Metal, ammonium, amine and other cations can be selected according to the required characteristics. Particularly, in the case of using magnesium, calcium, zinc, or the like, which is a polyvalent metal ion, the shrinkage rate tends to be high, which is particularly suitable. For example, for acrylonitrile fibers formed by joining two kinds of acrylonitrile polymers side by side, the above-mentioned crosslink introduction and hydrolysis are performed to form a carboxyl group. When a polyvalent metal ion such as magnesium, calcium, or zinc is selected as the opposite ion , It is easy to obtain a crosslinked acrylic fiber having a crimp ratio of 10% or more.

The method of adjusting the ratio of the base-type carboxyl group to the H-type carboxyl group to the above-mentioned range can be exemplified by ion exchange treatment using a metal salt such as nitrate, sulfate, hydrochloride, etc. A method in which hydrochloric acid, formic acid, or the like is subjected to an acid treatment or a pH adjustment treatment is performed using an alkali metal compound or the like.

Moreover, in the crosslinked acrylic fiber of this invention, it is desirable that the carboxyl group exists in all the fibers. When a large amount of carboxyl groups are concentrated in a part of the fibers, some of them will become brittle and have adhesiveness due to moisture absorption or water absorption. The presence of carboxyl groups in all the fibers can suppress embrittlement or adhesion of the fibers, and more carboxyl groups can be introduced. Therefore, fibers having high practicality and high hygroscopicity can be produced.

The crosslinked acrylic fiber of the present invention produced as described above has the characteristics of having a high moisture absorption rate and sufficient crimp sufficient to obtain practical bulkiness and carding processability. Therefore, in the case of containing the constituent fiber using the crosslinked acrylic fiber of the present invention as a fibrous structure, it can be inferred that the heat retention is improved due to the high bulkiness obtained by the crimping, and it is also caused by the body. The sweltering feeling caused by body fluids is reduced, so that a comfortable temperature environment can be achieved.

Since the crosslinked acrylic fiber of the present invention can form a fiber structure alone or in combination with other materials, it is more useful. As far as the appearance of such a fiber structure is concerned, it includes cotton, yarn, knitted fabric, woven fabric, non-woven fabric, flannel, paper, and the like. Regarding the contained form of the crosslinked acrylic fiber of the present invention in this structure, it is a thing obtained by mixing with other materials and substantially uniformly distributed, or when the present invention has a multilayer structure The crosslinked acrylic fibers are concentrated in any layer (single layer or multiple layers), or the crosslinked acrylic fibers of the present invention are distributed in each layer at a specific ratio.

Other materials that can be used in combination in the fiber structure of the present invention are not particularly limited. Commonly used natural fibers, organic fibers, semi-synthetic fibers, and synthetic fibers can be used, and inorganic fibers, glass fibers, and the like can also be used depending on the application. Specific examples include cotton, hemp, silk, wool, nylon, rayon, polyester, acrylic fiber, and the like. In addition, other materials used in combination may be materials such as feathers, resins, and particles.

There are countless combinations of the combination of the fiber structure of the present invention with the above-mentioned exemplified appearance form, contained form, and other materials. What kind of structure is formed can consider the use of cross-linked acrylic fibers for the final product (such as seasonal, sports or underwear, mid-layer clothing, outerwear, capes, curtains or carpets, bedding or cushions, The method of using the insole, etc.), the required function, and the method of imparting the function are determined appropriately. For example, when the fiber structure is a stuffed cotton, for example, it can be combined with polyester, wool, feather, etc., for example. In the case of a cotton pad, for example, for example, there is a case where the cross-linked acrylic fiber and feather of the present invention are mixed at a ratio of 5:95 to 75:25 by weight.

The manufacturing method of the padding of this invention is not specifically limited, It is suitable to employ a well-known general padding manufacturing method. For example, the following method is suitable: using a fiber separator to separate the raw cotton into fibers in advance, mix them, and then use a carding machine to process the fibers into a fiber network. In addition, for the purpose of imparting morphological stability, a step of winding fibers such as needle punch or water punch, and an interfiber bonding step using a hot-melt adhesive resin may be added. "Example"

Hereinafter, the present invention will be specifically described by way of examples. Unless otherwise specified, "parts" and "percentages" in the examples are expressed on a weight basis. The evaluation method of the characteristics in an Example is as follows.

(1) Amount of carboxyl group About 1 g of fiber sample was immersed in 50 ml of a 1 mol / L hydrochloric acid aqueous solution for 30 minutes. Next, the fiber sample was immersed in water at a bath ratio of 1: 500. After 15 minutes, it was confirmed that the pH of the water bath was 4 or more, and then dried (in the case where the pH of the water bath was 4 or less, the water was washed again). Next, about 0.2 g of the fully dried fiber sample (W1 (g)) was finely weighed, 100 ml of water was added, 15 ml of a 0.1 mol / L sodium hydroxide aqueous solution, 0.4 g of sodium chloride, and Phenolphthalein and stir. After 15 minutes, the sample fibers were separated from the filtrate by filtration, and then the sample fibers were washed with water until the phenolphthalein did not develop color. The mixed solution of the washing water and the filtrate at this time was titrated with a 0.1 mol / L hydrochloric acid aqueous solution until the phenolphthalein did not appear colored, and the consumption of the hydrochloric acid aqueous solution was determined. From the obtained measured values, the total carboxyl group amount was calculated according to the following formula. Amount of carboxyl group [mmol / g] = (0.1 × 15－0.1 × V1) / W1

(2) Moisture absorption at 20 ° C x 65% RH Using a hot air dryer, approximately 2.5 g of a fiber sample was dried at 105 ° C for 16 hours and the weight (W2 [g]) was measured. Next, this fiber sample was placed in a constant temperature and humidity chamber adjusted to a temperature of 20 ° C and 65% RH, and left for 24 hours. The weight (W3 [g]) of the fiber sample which had been absorbed in this way was measured. From these measurement results, a 20 ° C. × 65% RH moisture absorption rate was calculated according to the following formula. 20 ℃ × 65% RH moisture absorption rate [%] = (W3－W2) / W2 × 100

(3) Curling rate Measured and calculated in accordance with JIS L1015.

(4) Specific volume (fluffy) Measured and calculated in accordance with JIS L1097.

(5) Carding passability For a sample fiber of 50 g with a fiber length of 70 mm, a sample roller made by Yamato Machinery Co., Ltd. was used in a constant temperature and humidity chamber adjusted to a temperature of 30 ± 5 ° C and 50 ± 10% RH. Comb machine (model SC-300L), it is made into carded fiber web. The obtained web shape was evaluated by the following criteria. ○: Entangling property is sufficient, and a fiber web without unevenness can be obtained. △: The entanglement is slightly insufficient, and there are variations in the fiber web. ×: The entanglement property is obviously insufficient, and the fibers are not connected to each other, and a fiber web cannot be obtained.

[Example 1] 90% by weight of acrylonitrile and 10% by weight of methyl acrylate acrylonitrile-based polymer Ap (limiting viscosity [η] = 1.5 in dimethylformamide at 30 ° C), 88% by weight Acrylonitrile and 12% by weight ethyl acetate acrylonitrile polymer Bp ([η] = 1.5) were dissolved in a 48% by weight sodium thiocyanate aqueous solution to prepare a spinning dope. In such a way that the composite ratio of Ap / Bp is set to 1/1, each spinning dope is introduced into a composite spinning device of Japanese Patent Publication No. 39-24301, and spinning, washing, drawing, and winding are performed according to common methods. Shrinking and heat treatment to obtain a single fiber fineness of 3.3 dtex side-by-side raw fiber composed of a polymer Ap and a polymer Bp.

In a 20% aqueous hydrazine hydrate solution, the raw fiber was subjected to a cross-linking introduction treatment at 98 ° C. for 5 hours and washed. The crosslinked fiber was immersed in a 3% by weight aqueous nitric acid solution and subjected to an acid treatment at 90 ° C for 2 hours. Next, it was subjected to a hydrolysis treatment at 90 ° C. for 2 hours in a 3% by weight aqueous sodium hydroxide solution, and treated with a 3.5% by weight aqueous nitric acid solution and washed with water. The obtained fiber was immersed in water, and sodium hydroxide was added to adjust it to pH 11, which is equivalent to twice the amount of carboxyl groups contained in the fiber, and immersed in an aqueous solution of magnesium nitrate at 50 ° C for 1 hour. The crosslinked acrylic fiber of Example 1 having an Mg base type carboxyl group was obtained by performing ion exchange treatment, washing with water, and drying. The evaluation results of the obtained fibers are shown in Table 1. In addition, when the infrared absorption measurement of the fiber was performed, it was confirmed that no absorption from the vicinity of 2250 cm ^{-1 of the} nitrile group was observed, and the nitrile group in all the fibers was hydrolyzed to introduce a carboxyl group.

[Example 2 and Example 3] In Example 1, the same procedure was performed except that the composite ratio of the acrylonitrile polymer Ap / acrylonitrile polymer Bp was changed to the range shown in Table 1. To obtain a side-by-side raw fiber with a single fiber fineness of 3.3 dtex. Using this raw fiber, the treatment after the cross-linking introduction treatment was performed in the same manner as in Example 1 to obtain the cross-linked acrylic fibers of Examples 2 and 3 having Mg base-type carboxyl groups. The evaluation results are shown in Table 1. In addition, in the infrared absorption measurement of these fibers, as in the case of the crosslinked acrylic fiber of Example 1, no absorption at around 2250 cm ^-1 from a nitrile group was observed.

[Example 4] The fiber of Example 4 having a Ca-based carboxyl group was obtained in the same manner as in Example 1 except that potassium nitrate was used instead of magnesium nitrate. The evaluation result of this fiber is shown in Table 1.

[Comparative Example 1] In Example 1, except that only the spinning dope obtained by dissolving the acrylonitrile-based polymer Ap with a 48% by weight sodium thiocyanate aqueous solution was used, the same procedure was performed, and only Raw fiber composed of polymer Ap with a single fiber fineness of 3.3 dtex. Using this fiber, the treatment after the cross-linking introduction treatment was performed in the same manner as in Example 1 to obtain a fiber of Comparative Example 1. The evaluation result of this fiber is shown in Table 1.

[Example 5] The fiber of Example 4 having a Na-based carboxyl group was obtained in the same manner as in Example 1 except that the ion exchange treatment was not performed using magnesium nitrate. The evaluation results of the fibers are shown in Table 2.

[Comparative Example 2] In Comparative Example 1, a fiber of Comparative Example 2 having a Na-based carboxyl group was obtained in the same manner except that ion exchange treatment was not performed using magnesium nitrate. The evaluation results of the fibers are shown in Table 2.

As shown in Table 1, Example 1 to Example 4 have both high moisture absorption and bulkiness, so they can be used as filling cotton that maintains heat retention and has a humidity control function. On the other hand, although Comparative Example 1 had the same moisture absorption rate, bulkiness was low. In addition, as shown in Table 2, Example 5 can obtain a good carding processability, while Comparative Example 2 has a low curling rate and a poor carding processability.

Claims (7)

A crosslinked acrylic fiber characterized by having a side-by-side structure formed of two kinds of acrylonitrile-based polymers by using a nitrogen-containing compound having a nitrogen number of 2 or more in one molecule The acrylonitrile-based fiber is a cross-linked acrylic fiber obtained by performing a cross-linking treatment and a hydrolysis treatment, and has a carboxyl group of 2 mmol / g to 10 mmol / g, and the crimp ratio is 7% or more. A crosslinked acrylic fiber characterized by having a crosslinked structure and having a carboxyl group amount of 2 mmol / g to 10 mmol / g, a crimp ratio of 7% or more, and a carboxyl group existing in all the fibers. The crosslinked acrylic fiber according to claim 1, wherein the amount of the carboxyl group is 5 mmol / g to 10 mmol / g. The crosslinked acrylic fiber according to claim 1 or 2, wherein the crimp ratio is 10% or more. The crosslinked acrylic fiber according to claim 1 or 2, which is a counter ion having a carboxyl group of a polyvalent metal ion. A fiber structure comprising the crosslinked acrylic fiber according to claim 1 or 2. A stuffing cotton comprising the crosslinked acrylic fiber according to claim 1 or 2.