JP3369508B2 - Hygroscopic fiber - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture absorbing / releasing fiber. More specifically, the water vapor adsorption isotherm steeply rises in a humidity range of 50% to 95% RH required for practical performance as a humidity control material, and has an excellent humidity control function in the humidity range, and The present invention relates to a moisture-absorbing and desorbing fiber having antibacterial properties and excellent processability, and a method for producing the same. 2. Description of the Related Art Hygroscopic agents such as silica gel, zeolite, sodium sulfate, activated alumina and activated carbon have the disadvantage that they have a small amount of moisture absorption, have a low moisture absorption rate and require high temperatures for regeneration, and are all practical for various uses. There was a problem to make it. B-type silica gel has a high difference in moisture absorption rate, but has a problem that a complicated process is required for processing into a nonwoven fabric or the like because of the hysteresis phenomenon and the spherical shape of the hygroscopic agent which is easy to fall off. . [0003] As a method of solving this problem, Japanese Patent No. 2623771 in which a deliquescent salt is impregnated into superabsorbent fibers.
The fiber obtained by this method is easy to process into a knit, woven or non-woven fabric, has a high moisture absorption and desorption rate, and has practical performance with no loss of the moisture absorbent. However, because the fiber surface is a hydrogel, it becomes tacky when it absorbs moisture, it is difficult to apply especially to wallpaper and futon, and it does not meet the antibacterial properties that have recently been increasing as social needs . A highly hygroscopic fiber (N-3) manufactured by Toyobo Co., Ltd.
No. 8) is a highly moisture-absorbing and desorbing fiber which has been proposed by means of Japanese Patent Application Laid-Open No. 9-158040, has hygroscopicity and moisture releasing properties, withstands repeated use, has antibacterial properties, and has good workability. However, this fiber has a large difference in moisture absorption in a humidity range of 50% to 95% in practical use in the field of a humidity control material, whereas a slight difference in moisture absorption is 35%.
There was a problem that there is only. [0005] Bell Oasis manufactured by Kanebo Co., Ltd. has a high difference in moisture absorption. However, when water is spilled, fibers swell and the tatami surface rises when the water is spilled. In addition, there is a problem that a complicated process is required for processing into a nonwoven fabric or the like having low fiber properties. SUMMARY OF THE INVENTION The present invention has solved the above-mentioned problems of the conventional humidity control material, and has a much higher moisture absorption between low humidity and high humidity environments than conventional products. Shows rate difference, fast moisture absorption and desorption rate, and is easy to handle, has excellent shape retention after moisture absorption, can be easily regenerated, and is suitable for improved moisture conditioning material that also has antibacterial properties An object of the present invention is to provide a fiber and a method for producing the fiber. [0007] The present inventors have intensively studied moisture-absorbing and desorbing fibers which have high fiber properties and have a large difference in moisture absorption required for practical performance of a humidity control material. That is, according to the present invention, the degree of swelling is 1.7 g / g or less, the sterilization rate is 90% or more, and the conditions of 20 ° C. × 50% RH and 20 ° C. × 95% R
A moisture-absorbing / desorbing fiber characterized in that the moisture-absorbing / desorbing fiber is a crosslinked acrylic fiber having a difference in moisture absorption from the H condition of 50 % by weight or more and 150% by weight or less . In the moisture absorbing and releasing fiber, an acrylic fiber having an acrylonitrile content of 85 to 95% by weight is subjected to a crosslinking treatment with a hydrazine-based compound, and the introduction of the crosslinking bond increases the nitrogen content by 1.0%. ~ 5.0% by weight
And then hydrolyzed with an alkali to partially remove the remaining nitrile groups from 3.0 to 6.0 meq / g of an alkali metal salt-type carboxyl group. Can be produced by converting to The present invention will be described below in detail. The present invention is a crosslinked acrylic fiber, and acrylonitrile (hereinafter referred to as AN) is used as the starting acrylic fiber.
It is a fiber formed of an AN-based polymer containing 5 to 95% by weight, and may be in any form such as a short fiber, a tow, a thread, a knitted woven fabric, a nonwoven fabric, or in the middle of a production process, a waste fiber, or the like. I do not care. The AN-based polymer may be any of an AN homopolymer, a copolymer of AN and another monomer,
Other monomers include vinyl halide and vinylidene halide; (meth) acrylic acid ester; sulfonic acid-containing monomers such as methallyl sulfonic acid and p-styrene sulfonic acid and salts thereof; (meth) acrylic acid , Carboxylic acid-containing monomers such as itaconic acid and salts thereof; acrylamide,
Examples include monomers such as styrene and vinyl acetate.
The monomer is not particularly limited as long as it is a copolymerizable monomer. As a method for introducing cross-linking with the hydrazine compound into the acrylic fiber, any method can be employed as long as the increase in the nitrogen content can be adjusted within the range of 1.0 to 5.0% by weight. , Hydrazine compound concentration 5-6
Means of treating at 0% at a temperature of 50 to 120 ° C. within 5 hours is industrially preferable. Here, an increase in the nitrogen content refers to a difference between the nitrogen content of the raw acrylic fiber and the nitrogen content of the acrylic fiber into which the crosslinking with the hydrazine compound has been introduced. If the increase in the nitrogen content is less than the above lower limit, a fiber having physical properties satisfactory for practical use cannot be finally obtained, and if it exceeds the upper limit, the swelling rate of the fiber becomes low, and the moisture absorption rate decreases. Moisture-absorbing fibers having a large difference cannot be obtained. The hydrazine compound used here includes hydrazine hydrate, hydrazine sulfate, hydrazine hydrochloride, hydrazine bromide, hydrazine carbonate, etc., and also contains plural amino groups such as ethylenediamine, guanidine sulfate, guanidine hydrochloride, guanidine phosphate, melamine, etc. Are exemplified. The present inventor has proposed that a part of the residual nitrile group after the crosslinking treatment with the hydrazine compound is 3.0 to 6.0 me.
As a method of converting into a q / g alkali metal salt-type carboxyl group, the above-mentioned subject is achieved by performing acid treatment A, followed by hydrolysis with an alkali compound after introduction of a cross-linking bond by treatment with a hydrazine-based compound. Was. According to this method, the acid treatment A after the introduction of the cross-linking A
Both the acid concentration and the alkali compound concentration in the next step can be made lower than the conventional method in which alkali hydrolysis is performed in one step, and can be easily converted into a large amount of alkali metal salt-type carboxyl groups, and can withstand processing. A moisture-absorbing / desorbing fiber is provided that maintains the desired strength. The acids used here are nitric acid, sulfuric acid,
Examples thereof include an aqueous solution of a mineral acid such as hydrochloric acid, an organic acid, and the like, but are not particularly limited. Before this treatment, the hydrazine-based compound remaining in the crosslinking treatment is sufficiently removed. Examples of the alkali used for performing the hydrolysis include a basic aqueous solution such as an alkali metal hydroxide, an alkaline earth metal hydroxide, and ammonia. Not done. The concentration of the acid or alkali used is not particularly limited, either, but a means for treating at 1 to 10% by weight at a temperature of 50 to 120 ° C within 2 hours is preferable from the industrial and fiber properties. There are roughly two methods for converting a carboxyl group generated by hydrolysis into an alkali metal salt type. One of them is hydrolysis with an alkali metal hydroxide, which directly generates an alkali metal salt type carboxyl group. The second is a method of hydrolyzing with an alkaline earth metal hydroxide, ammonia or the like to once generate a different type of carboxyl group, and then replacing the group with a desired alkali metal salt type. The substitution of the salt form of the carboxyl group in the second method may be carried out by means of alkali metal hydroxide or a salt compound of the metal to immediately convert to the alkali metal salt form, or by an acid treatment (the above-mentioned acid treatment A). There is a means for converting the carboxyl group to H (acid) form by acid treatment B) and then converting the carboxyl group to an alkali metal salt form with the above alkali metal compound. Since the amount of the alkali metal salt type carboxyl group required by the present invention is 3.0 to 6.0 meq / g, the "type" of the remaining carboxyl group is not limited as long as this amount is secured. As the alkali metal salt type, Li,
Na and K, and when the salt type carboxyl groups are formed in the above-described amounts, the fiber has a swelling degree of 1.0 to 3.0 g / g. The types of the salt of the carboxyl group are Li, Na, and K, but are not limited to any one of them, and two or more of these may be mixed in the same product fiber. . The means for evaluating the degree of swelling will be described later. After the conversion treatment to the alkali metal salt type, the fiber to be treated is subjected to washing with water, drying and, if necessary, oil treatment. If the alkali metal salt type carboxyl group is less than 3.0 meq / g, moisture absorption / desorption cannot be obtained, and if it exceeds 6.0 meq / g, fiber properties satisfactory for practical use are obtained. I can't. The introduction of crosslinks is performed properly,
As a result of a part of the nitrile group being converted to an alkali metal salt type carboxyl group of 3.0 to 6.0 meq / g, the swelling degree of the fiber of the invention is 1.0 to 3.0 g / g, and the tensile strength is also 0. 0.7dN / tex or more, and the sterilization rate is 90% or more. Such a fiber is disclosed in Japanese Patent Application Laid-Open No.
No. 58040 could not obtain the invention disclosed,
Fiber with a large difference in moisture absorption between 50% by weight and 150% by weight or less under the conditions of 20 ° C. × 50% RH and 20 ° C. × 95% RH, which is more effective in practical performance than conventional fibers or methods. Large difference in moisture absorption rate is greatly improved. Since the fiber of the present invention swells where the alkali metal salt-type carboxyl group is formed during the manufacturing process, it is used to reduce the load in the drying process and to process the final product such as a nonwoven fabric. Oil is attached for the purpose of improving the processability of the oil, but if an alkylamide quaternary cationic oil is attached to the fiber in the range of 1.0 to 2.5% omf as the oil, moisture absorption between the above-mentioned different conditions can be achieved. It was found that the degree of swelling of the fiber was reduced by 1 g / g without changing the rate difference. The present findings provide an industrially advantageous method for producing the fiber of the present invention. If the amount of the oil agent is less than 1.0% omf, the degree of swelling does not decrease. On the other hand, if the amount of the oil agent adhered is 2.5% omf or more, problems such as deterioration in workability to a nonwoven fabric or the like occur. Preferred examples of such alkylamide quaternary cationic oils include alkylamidopropyldimethyl β
-Hydroxyethylammonium nitrate R = (C16-
C18), stearylamidoethyldimethylhydroxyethylammonium chloride, cetylamidoethyldiethylmethylammonium methylsulfate and the like. According to the present invention, the tensile strength is 0.7 dN / tex.
As described above, it is possible to provide a fiber having a high moisture absorption / release rate, a large difference in moisture absorption rate, and also having antibacterial properties. As described above, the starting fiber of the present invention may be in the middle of an acrylic fiber production process or may be obtained after the fiber is subjected to spinning or the like. As the starting acrylic fiber, a fiber after drawing and before heat treatment (a fiber which is spun from a spinning solution of an AN polymer in accordance with a conventional method, drawn and oriented, and which has not been subjected to heat treatment such as dry densification and wet heat relaxation treatment; Alternatively, by using a water-swellable gel-like fiber after dry / wet spinning and stretching: a degree of water swelling of 30 to 150%), the dispersibility of the fiber in the reaction solution, the permeability of the reaction solution into the fiber, and the like are improved. This is desirable because the introduction of the crosslinking bond and the hydrolysis reaction can be performed uniformly and promptly. These starting acrylic fibers are filled in a vessel equipped with a pump circulation system, and the above-mentioned cross-linking is introduced, acid treatment A, alkali treatment, formation of an alkali metal salt type carboxyl group, washing with water, It is desirable to take measures such as oil treatment from the viewpoints of safety, uniform reactivity, etc. on the apparatus. A dyeing machine is exemplified as such a device (a container provided with a pump circulation system). Due to such a large difference in moisture absorption, the fiber of the present invention can be applied to applications that have not been used conventionally or applications that cannot be met with conventional fibers. For example, moisture-absorbing and moisture-absorbing materials (clothing, building materials, wallpaper, batting, etc.) that absorb water vapor before dew condensation and absorb water vapor.
Temperature control materials and the like. In addition, examples of use methods such as drying in a closet, a basement, a floor, a bathroom, etc., and using as a part of a coating material such as an electronic material that dislikes moisture very much, and a high moisture absorption rate difference performance can be exemplified. Further, since this fiber has high hydrophilicity, it can be applied to uses such as absorbing moisture and releasing water vapor. Such an effect can be further enhanced by using fine denier yarn, hollow fiber, or porous fiber as the starting fiber. It is also effective to use fibrillated fiber form, raised or planted cloth or paper. Although the fiber of the present invention is a moisture-absorbing and desorbing fiber, the fiber does not have a tacky state when it absorbs moisture, has a moderate wetness, and has an appropriate elongation. For this reason, it is a moist and supple fiber. Utilizing this property, it can be applied to moisturizing materials, beauty materials, high texture materials, and the like. Also, when applied to a cloth or paper impregnated with a hydrophilic chemical or the like, there is an effect that a material having a high moisture retention and a high impregnation amount can be used to make the material difficult to dry.
Such examples include those impregnated with a disinfecting solution, lotion, fragrance, deodorant, bactericide, insect repellent, and the like. The moisture absorption / release properties of the fiber of the present invention are mainly exhibited by the alkali metal salt type carboxyl group. By controlling this amount, the moisture absorption / release properties can be controlled. For example, a method in which a large amount of a carboxyl group is introduced by hydrolysis, and the amount of conversion into an alkali metal salt-type carboxyl group is controlled to control the moisture absorption / release properties can be performed. When such a method is employed, there are various methods such as an acid treatment followed by hydrolysis with an alkali, but a method in which an alkali metal salt-type carboxyl group can be present at 3.0 to 6.0 meq / g. There is no particular limitation if it exists. However, industrially, there is a method of controlling the amount of the alkali metal salt-type carboxyl group by performing the acid treatment B and then performing the alkali metal salt treatment, which is the second method described above, which is followed by hydrolysis with an alkali, followed by treatment with an alkali metal salt. preferable. Although the fiber of the present invention has a high moisture absorption / release rate, this rate can also be controlled by the fiber itself or the density of a molded article made of the fiber. When a very high moisture absorption / release rate is required, use thin moisture absorption / release fibers, use fibrillated moisture absorption / release fibers, reduce the fiber density, raise the hair, and plant hair. For example, a method of increasing the area of contact between the moisture-releasing fiber and the moisture-containing gas can be employed. Also, when a slow moisture absorption and desorption rate is required,
Non-woven fabric, to increase the fiber density by increasing the processing density to paper or by increasing the number of twists during spinning, or to use thick moisture-absorbing and desorbing fibers, or other fibers that can transmit water vapor through the fibers of the present invention A method such as covering with a substance can be adopted. The fibers of the present invention also have a high difference in moisture absorption, moisture absorption and desorption, and antibacterial properties as described above. The antibacterial property is indicated by a sterilization rate measured by a shake flask method as described in Examples, and the fiber of the present invention exhibits a sterilization rate of 90% or more. The fibers of the present invention have these properties and can be handled very safely. Since ordinary fibers are in an environment where bacteria are likely to be generated when they absorb moisture, it is often necessary to use antibacterial fibers in combination for hygiene purposes. You have. In addition, since it has flame retardancy, it is a very safe material to be used at home with almost no risk of fire even when high temperatures are applied for regeneration or the like. Since the material of the present invention has a crosslinked structure having excellent chemical resistance, the fiber form can be maintained even when treated with various chemicals. Therefore, it can be applied as a structure holding material of a structural material containing an acid, an alkali or the like. The reason why the moisture-absorbing / desorbing fiber according to the present invention and the production method have both a high moisture-absorbing rate difference and a high moisture-absorbing / desorbing property while having antibacterial properties has not been sufficiently elucidated. Think like. That is, although the fiber according to the present invention starts from an AN-based polymer, the side chain bonded to the polymer chain has a hydrazine-based compound because the nitrile group is substantially reduced. It is considered that the nitrogen-containing cross-linking structure formed by the above reaction and the alkali metal salt-type carboxyl group formed by the hydrolysis reaction of the nitrile group occupy the majority. In general, the alkali metal salt-type carboxyl group has a hygroscopic property, and it is considered that the present invention further enhances the hygroscopic property by having a very large amount and a cross-linked structure containing a large amount of nitrogen. In addition, since the carboxyl group is of an alkali metal salt type and has an appropriate cross-linking structure, a mechanism in which functional groups that should be involved in hygroscopicity do not contribute to hygroscopicity due to hydrogen bonding between the functional groups is suppressed,
It is estimated to have a very high difference in moisture absorption rate and moisture absorption / release properties. The fiber of the present invention has a fiber strength that can withstand various processes even if it contains a large amount of an alkali metal salt type carboxyl group. This is estimated as follows. In other words, since the acid treatment A and the alkali treatment are performed in two stages of hydrolysis, the concentration of the reaction reagent is extremely low and the treatment time can be shortened. For this reason, it is presumed that the fiber does not undergo severe treatment and has high fiber strength even if the amount of the alkali metal salt type carboxyl group is large. Naturally, it may be caused by having a crosslinked structure. It is presumed that the antibacterial property is provided by a crosslinked structure containing nitrogen. Furthermore, the absence of stickiness even when absorbing moisture may be due to the high degree of crosslinking and the effect of the oil agent. The present invention will be specifically described below with reference to examples. Parts and percentages in the examples are on a weight basis unless otherwise specified. The amount of alkali metal salt-type carboxyl groups in the fiber, the moisture absorption, the degree of swelling, the oil adhesion and the antibacterial activity were determined by the following methods. (1) Alkali metal salt type carboxyl group content (meq / g) About 1 g of sufficiently dried test fiber was precisely weighed (Xg), and 200 ml of water was added thereto, followed by heating to 50 ° C. While 1N
An aqueous hydrochloric acid solution was added to adjust the pH to 2, and then a titration curve was obtained with a 0.1N aqueous sodium hydroxide solution according to a conventional method. From the titration curve, the consumed amount of aqueous caustic soda (Ycc) consumed by all the carboxyl groups was determined, and the total carboxyl group amount (meq / g) was calculated by the following equation. (Total carboxyl group content) = 0.1 Y / X Separately, a titration curve was obtained in the same manner without adjusting the pH to 2 by adding a 1N aqueous hydrochloric acid solution during the above-mentioned total carboxyl group content measurement operation. The basis weight (meq / g) was determined. From these results, the amount of the alkali metal salt-type carboxyl group was calculated by the following equation. (Amount of alkali metal salt type carboxyl group) = (Total carboxyl group amount) − (Amount of acid type carboxyl group) (2) Moisture Absorption Rate (%) About 5.0 g of sample fiber was dried at 120 ° C. with a hot air drier. After drying for an hour, the weight is measured (W1 g). Next, the sample was heated to a temperature of 20.
The sample is placed in a predetermined humidity chamber (50% RH and 95% RH) at 24 ° C. for 24 hours. The weight of the sample thus absorbed is measured (W2 g). From the above measurement results, it was calculated by the following equation. (Moisture absorption) = (W2−W1) / W1 × 100 The difference in moisture absorption is the 50% RH at 20 ° C. thus obtained.
And 95% RH. (3) Degree of swelling (g / g) About 3 g of the sample fiber is dried at 70 ° C. for 3 hours using a hot air drier, and the weight is measured (W1 g). Next, the sample was
After being immersed in a beaker 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 (W2 g). (Swelling degree) = (W2-W1) / W1 (4) Adhesion rate of oil agent (% omf) About 3 g of the sample fiber is precisely weighed (W1), put into a glass cylindrical filter paper, and put into an extraction cylinder. A kolben containing 100 to 120 ml of a solvent (primary ethyl alcohol) is joined. Furthermore, the cooling tube was joined and 97 ° C on a water bath.
The above is extracted for 2 hours. When the solvent in the kolben is sufficiently raised to the extraction cylinder, the kolben is removed, the solvent is put into a petri dish, and this is evaporated to dryness in a water bath. The weight (W2) of the oil agent remaining in the petri dish is obtained and calculated by the following equation. (Oil agent adhesion rate) = W2 / (W1−W2) × 100 (5) The antibacterial test bacterium was Klebsiella pneumoniae, and the processing effect evaluation test of the antibacterial and deodorant processed product, the manual shake flask method (Fiber product sanitary processing consultation) Society, 1988), and the results are shown in terms of% of sterilization. Example 1 AN 90% and methyl acrylate (hereinafter referred to as MA)
A spinning stock solution obtained by dissolving 10 parts of 10% AN polymer (intrinsic viscosity [η]: 1.2 in dimethylformamide at 30 ° C .: 1.2) in 90 parts of a 48% aqueous solution of rhoda soda was spun and drawn according to a conventional method. After performing a total draw ratio of 10 times), drying was performed in an atmosphere of dry bulb / wet bulb = 120 ° C./60° C. (process shrinkage: 14%) to obtain a raw fiber I having a single fiber fineness of 1.5d. The raw material fiber I was subjected to crosslinking treatment and conversion of a nitrile group into an alkali metal salt type carboxyl group under the conditions shown in Table 1, followed by dehydration, washing and drying to obtain a fiber No. 1.
1-8 were obtained. The properties of the obtained fiber were examined, and the results are shown in Table 1. [Table 1] The amount of increase in nitrogen is in the range of 1.0 to 5.0% by weight, and the amount of the Na-type carboxyl group is 3.0 to 6.0 meq.
/ G of the fiber of the present invention example. Nos. 1 to 4 show a high difference in moisture absorption with a degree of swelling of 1.0 to 3.0 g / g, and it can be seen that the samples have both high tensile strength and antibacterial properties. On the other hand, fiber No. In No. 5, since the amount of increase in nitrogen was less than 1.0% by weight, the amount of Na-type carboxyl groups was within the range recommended by the present application and the difference in moisture absorption was large, but the tensile strength was as low as 0.2 dN / tex. For this reason, the fibers were brittle and did not have physical properties that could withstand processing such as card hanging. Similarly, the fiber No. which satisfies the amount of Na-type carboxyl groups but has an increased amount of nitrogen exceeding the recommended amount of the present invention. No. 6 has sufficient tensile strength, but the purpose is not achieved with respect to the degree of swelling of the fiber and the difference in moisture absorption. On the other hand, the fiber No. which satisfies the increased amount of nitrogen but has less conversion to the Na-type carboxyl group than the recommended amount of the present invention. No. 7 has a tensile strength but does not achieve the purpose in terms of both the degree of swelling of the fiber and the difference in moisture absorption. Similarly, although the amount of increase in nitrogen is appropriate, the fiber No. whose conversion to Na-type carboxyl groups is larger than the recommended amount of the present invention. No. 8 has a sufficient difference in moisture absorption, but has a high degree of fiber swelling and a tensile strength of 0.4 d
The value is as low as N / tex. For this reason, the fibers were brittle and did not have physical properties that could withstand processing such as card hanging. Example 2 No. 2 obtained in Example 1 5 g of the fiber of Example 1 was replaced with 5 g of the alkali metal compound or alkaline earth metal compound shown in Table 2.
% Aqueous solution at a temperature of 40 ° C. for 5 hours, followed by washing with water and drying. 9-11 were obtained. The characteristics of the obtained fiber were examined, and the results are shown in Table 2. [Table 2] Inventive fiber No. 1 No. 1 which is a fiber converted into Na type or Li type. No. 9, K type. 10
Fiber No. The fiber having a Ca-type carboxyl group of No. 11 has a low degree of swelling of the fiber and an improved tensile strength, but the difference in moisture absorption rate is low and the purpose is not achieved, and alkali metal is effective as a salt type of the carboxyl group. I understand. Example 3 No. 3 obtained in Example 1 5 g of one fiber was treated with alkylamidopropyldimethyl β-hydroxyethylammonium nitrate (R
= C16 to C18) in a 0.5% aqueous solution and a 1.5% aqueous solution at 40 ° C. for 1 hour, followed by dehydration and drying. 12, 13 were obtained. The properties of the obtained fiber were examined, and the results are shown in Table 3. [Table 3] Fiber No. 1 having an alkylamide quaternary cation oil adhering amount of 1.5% was used. Fiber No. 12 having the same oil agent adhesion amount of 0.5% as that of No. 12 As compared with No. 13, the difference in the moisture absorption rate did not change, but No. In the case of No. 12, since the degree of swelling of the fiber is reduced, the burden of drying the fiber in the manufacturing process is reduced, and it can be seen that the fiber can be manufactured industrially advantageously. On the other hand, when the oil agent adhesion amount is 0.5%, the fiber No. There is no difference in the degree of swelling as compared with No. 1, and it is understood that the adhesion of 1.0% or more is necessary for the purpose of reducing the drying load. According to the present invention, there is provided a means for industrially advantageously producing moisture-absorbing and desorbing fibers having a large difference in moisture absorption required for practical use as a humidity control material, having fiber properties which are not problematic in processing. What can be provided is a remarkable effect of the present invention. The moisture-absorbing and desorbing fiber thus obtained has not only improved moisture-absorbing and desorbing properties, but also has a greatly improved difference in moisture-absorbing rate. It also has antibacterial properties, has a low regeneration temperature, and is fibrous, so it can be processed into various forms such as non-woven fabric, knitted fabric, and woven fabric. Well,
Since the rate of moisture absorption and desorption can also be controlled by controlling the density and the like, it can be widely applied to fields where moisture absorption and desorption properties or heat generation due to moisture absorption are required.

Claims (1)

(57) [Claims] [Claim 1] Swelling degree is 1.7 g / g or less, and sterilization rate is 9
0% or more, 20 ° C. × 50% RH condition and 20 ° C. × 9
Difference in moisture absorption rate from 5% RH condition is 50% by weight or more and 150% by weight
Moisture-absorbing / desorbing fiber, characterized in that it is a crosslinked acrylic fiber of not more than the amount .