JPH09316782A - Durable moisture-absorption and desorption processing for synthetic fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart moisture-absorbing and desorbing properties excellent in color fastness and rich in durability by applying a modified polyvinyl alcohol and a blocked isocyanate to a dyed fabric of a synthetic fiber. SOLUTION: An anionic and/or nonionic modified polyvinyl alcohol (A) obtained by subjecting a polyvinyl alcohol to Michel addition with a vinyl compound such as 21-acrylamide-2-methylpropanesilfonic acid or acrylamide or obtained by partially or completely hydrolyzing the material after the Michel addition is firmed. A water-soluble or water-dispersible blocked isocyanate (B) blocked with a blocking agent such as phenol which is dissociated by heat is blended with the component A and the resultant blend is applied to a dyed fabric of a polyester fiber to carry out moisture-absorbing and desorbing processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a durable process for absorbing and releasing moisture for synthetic fibers, which can impart not only water absorbency but also excellent moisture absorbing and releasing performance and dyeing fastness.

[0002]

2. Description of the Related Art Conventionally, various attempts have been made to impart a water-absorbing performance having durability by applying a treating agent to synthetic fibers by post-processing.

However, most of these treatment methods are intended to impart water absorbing performance by using a compound mainly composed of polyethylene oxide chains, and until a sufficiently satisfactory water absorbing ability and moisture absorbing / releasing ability are imparted. Has not reached.

Further, when it is applied to a dyed cloth, it has a drawback that the dyeing fastness is remarkably lowered, which is not preferable in practical use. Therefore, for practical use, it was necessary to limit the use to a dyed cloth having a good dyeing fastness or a dye having a good dyeing fastness, or to only a white cloth.

[0005]

Therefore, in order to improve the effects of imparting water absorbency, hygroscopicity and dyeing fastness, in Japanese Patent Publication No. 515826/1993, a natural polysaccharide derivative is reacted with an organic polyisocyanate. Obtained by
A blocked product obtained by blocking an isocyanate group of a urethane compound having an isocyanate group has been proposed. This may give some water absorption, hygroscopicity, dye fastness, but is still not sufficient.

[0006]

To solve the above problems, the present invention provides durable water-absorbing, hygroscopic, moisture-releasing and dyeing fastness without impairing the texture of synthetic fiber products. It was made as a result of intensive research into
It is characterized by using an anionic and / or nonionic modified polyvinyl alcohol (hereinafter referred to as modified PVA) and a specific blocked isocyanate.

That is, in the durable moisture-absorption / desorption processing method for synthetic fibers according to claim 1, (A) a modified polyvinyl alcohol having an anionic and / or nonionic group,
(B) A water-soluble or water-dispersible blocked isocyanate having an isocyanate group blocked with a blocking agent that dissociates by heat is applied to a synthetic fiber product,
Then, the synthetic fiber product is heat-treated.

In the processing method of claim 2, the modified polyvinyl alcohol of the component (A) in the processing method of claim 1 is obtained by Michael-adding a vinyl compound to polyvinyl alcohol, or partially or after the Michael addition. A modified polyvinyl alcohol obtained by complete hydrolysis is used.

Further, in the processing method according to claim 3, as the modified polyvinyl alcohol of the component (A), modified polyvinyl alcohol obtained by partially or completely hydrolyzing acrylonitrile or acrylamide by Michael addition to polyvinyl alcohol. To use.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION First, a modified PVA having an anionic property and / or a nonionic property, which is the component (A) of the present invention.
Will be described in detail below.

The degree of polymerization of the modified PVA used in the present invention is not particularly limited, but it is preferably 200 to 8000, more preferably 300 to 4000. If the degree of polymerization is less than 200, durable moisture absorption / release properties may not be obtained, and if it exceeds 8000, the texture of the product may be hard.

The modification ratio of the anionic and / or nonionic groups is preferably 2.0 to 40 mol%, 4.0.
˜30 mol% is more preferred. If it is less than 2.0 mol%, it is difficult to obtain sufficient moisture absorption and desorption properties, while if it exceeds 40 mol%, not only the production is difficult but also the cost is increased.

The kind of nonionic group is a nitrile group,
Examples thereof include an amide group and an ester group, and an amide group is preferable from the viewpoint of giving sufficient moisture absorption / release properties.

Examples of the method for introducing an amide group into PVA include a method in which acrylamide and vinyl acetate are copolymerized and then saponified, and a method in which acrylamide is subjected to a Michael addition reaction with PVA. From the viewpoint that a high denaturation rate can be obtained, a method in which PVA is subjected to a Michael addition reaction with acrylamide is preferable.

In addition, a method of Michael addition reaction of acrylic acid ester such as methyl acrylate with PVA,
Similarly, there is a method in which a mono- or diacrylate of polyethylene glycol is subjected to a Michael addition reaction and a method in which a mono- or diglycidyl ether of polyethylene glycol is subjected to an addition reaction.

Examples of the type of the anionic group include a carboxyl group, a sulfone group, and a phosphoric acid group.
A carboxyl group and a sulfone group are preferable from the viewpoint of ease of production.

As the carboxyl group-containing modified PVA,
For example, a so-called copolymerization-modified PVA obtained by copolymerizing vinyl acetate and itaconic acid or maleic acid and then saponifying, or directly introducing a carboxyl group into PVA,
Examples include so-called post-modified PVA and the like.

As a method of introducing a carboxyl group into PVA by post-modification, PVA is monoesterified with maleic anhydride or the like, PVA is replaced with monochloroacetic acid or the like, acrylic acid or the like is added to PVA by a Michael addition reaction. Similarly, there is a method of subjecting acrylonitrile, acrylamide, etc. to a Michael addition reaction and then hydrolyzing. Among these, the method of adding acrylonitrile or acrylamide to Michael and then hydrolyzing it is preferable in that a reaction having a high reaction rate and a high modification rate can be obtained.

On the other hand, as a method for introducing a sulfone group into PVA, for example, vinyl acetate and vinylsulfonic acid, styrenesulfonic acid, allylsulfonic acid, methallylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (hereinafter , AMPS) and the like, followed by saponification, vinyl sulfonic acid or its salt, AM
There is a method of adding PS or a salt thereof to PVA by Michael. Among them, AMPS or a salt thereof is used as PVA because of its high reaction rate and high modification.
The method of adding Michael to is preferred.

When introducing an anionic and / or nonionic group into these PVA, two or more methods or agents may be used in combination. Further, two or more types of denaturation can be performed with one type of drug.

As an example of carrying out two or more types of modification with one type of agent, there is a method in which PVA is subjected to Michael addition reaction with acrylamide and then partially hydrolyzed with alkali. This gives an anionic group (carboxyl group)
And a nonionic group (amide group) can be introduced at the same time.

Next, the component (B) of the present invention will be described below.

The blocked isocyanate used in the present invention is obtained by blocking an organic polyisocyanate with a blocking agent that is dissociated by heat and is used as an aqueous solution of about 10 to 40%.

Examples of the organic polyisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, and the like. Trimerized product obtained by previously reacting the diisocyanates of 1) with a low molecular weight polyol such as trimethylolpropane, and further tris- (isocyanate hexyl) -buret polyisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate And so on.

The blocking agent used in the present invention is preferably one which can be blocked by reacting with an organic polyisocyanate at room temperature or higher and 100 ° C. or lower,
Specifically, phenols such as phenol, chlorophenol and cresol, p-tert-butylphenol, p-sec-butylphenol, p-sec-amylphenol, p-octylphenol, alkylphenols such as p-nonylphenol, isopropyl alcohol, Secondary or tertiary alcohols such as tert-butyl alcohol, oximes such as acetoxime, methylethylketoxime and cyclohexanone oxime, lactams such as ε-caprolactam and δ-valerolactam, dialkyl esters of malonic acid, acetylacetone and alkyl acetoacetate. Examples thereof include active methylene compounds such as esters, basic nitrogen compounds such as 3-hydroxypyridine and 8-hydroxynoline, and bisulfite salts. The reaction of these with the above-mentioned organic isocyanate can be carried out by a known method using a urethanization catalyst or without a catalyst. Specifically, the organic polyisocyanate and the blocking agent may be reacted at room temperature to 100 ° C. for 10 minutes to 10 hours until the reaction is completed.
Here, the amount of the blocking agent is at least equimolar to the NCO group of the organic polyisocyanate. If necessary, a solvent that does not react with isocyanate, such as methyl ethyl ketone, dioxane, ethyl acetate, toluene, etc., is used.
After confirming that the free isocyanate group became 0%,
The solvent is removed, or water is added as it is to a desired concentration to obtain an aqueous solution.

The above organic polyisocyanate and blocking agent may be used in combination of two or more, if necessary.

The free isocyanate of the urethane prepolymer obtained by the reaction of the above-mentioned organic isocyanate with a compound having two or more active hydrogens blocked with the above blocking agent also corresponds to the blocked isocyanate of the present invention. .

The blocked isocyanate synthesized as described above becomes a stable water-soluble or water-dispersible heat-reactive component. That is, the blocking agent is dissociated by heat treatment at 100 to 180 ° C., and the isocyanate group reacts with active hydrogen or the like of the modified PVA which is the component (A),
Since it is crosslinked and polymerized, it forms a film that has both excellent durability and moisture absorption / release properties compared to conventional water-based urethanes.

Further, since the modified PVA as the component (A) has no affinity for the dye used for dyeing the synthetic fiber, the adverse effect on the dyeing fastness is very small as compared with the conventional water-based urethanes.

The mixing ratio of the component (A) and the component (B) is (A) :( B) = 1.0: 9 in terms of solid content in terms of weight ratio.
It is 9.0 to 99.0: 1.0.

When the component (A) is less than 1.0% by weight,
Sufficient moisture absorptive and desorptive properties and dyeing fastness cannot be obtained, and if the content of the component (A) exceeds 99.0%, sufficient durability cannot be obtained.

In the processing method of the present invention, the modified PVA having the anionic and / or nonionic group as the component (A) and the water-soluble or water-dispersible thermally reactive block forming component (B) are used. By imparting a fiber processing agent containing isocyanate as an essential component to various synthetic fiber products and then subjecting it to heat treatment, it is possible to impart durable moisture absorption / release properties and dyeing fastness to the synthetic fibers.

As the method for applying the fiber processing agent to the synthetic fiber product, various methods currently used such as dipping, spraying and coating can be used.

The types of synthetic fibers to be treated according to the present invention include polyester fibers, polyamide fibers, polyacrylic fibers, polyolefin fibers, vinylon fibers, polypropylene fibers, spandex fibers or blends of these and natural fibers. Examples include synthetic fibers. In terms of shape, it can be applied to any fabric such as yarn, woven fabric, and non-woven fabric.
It is also effective for a cloth obtained by cross weaving, cross knitting, and crossing. In some cases, knitted fabric, woven fabric, non-woven fabric, etc. can be obtained after the yarn, stable, filament, tow-shaped treatment.

Further, in the processing method of the present invention, resins which are usually used, such as urea resins and melamine resins, are used as long as they have excellent dyeing fastness and do not impair durable moisture absorption and desorption. Resin, glyoxal resin, acrylic resin, epoxy resin, phenol resin, silicone resin, fluorine resin, polyurethane resin, and softener,
A penetrant or the like can be added to the resin processing liquid.

[0036]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. It should be noted that, in the text, "part" and "%" are all based on weight unless otherwise specified.

[Production Example of Component (A)] Production Example 1 75 parts of vinyl acetate, 500 parts of methanol, 4.85 parts of itaconic acid, 1.10 parts of NaOH and 0.3 parts of azobisisobutyronitrile were placed in a separable flask. Charged in, 70
Polymerized at 9 ° C. for 9 hours. At this time, the polymerization rate was 81%. After removing unreacted vinyl acetate, 1/1 of the theoretical amount
0 NaOH was added and saponified at 40 ° C. for 5 hours.

The carboxy-modified PVA thus obtained had a polymerization degree of 1,200 and a saponification degree of 96.3 mol%. In addition, as analyzed by NMR, the carboxyl modification rate was 3.3 mol%.

Production Example 2 PVA (Polymerization degree: 1,700, Saponification degree: 99.1 mol%)
40 parts, maleic anhydride 15 parts, sodium hydrogen carbonate 4
Parts, 350 parts of toluene were charged into a separable flask,
Stirred at 70 ° C. for 5 hours.

The product obtained was filtered and then purified several times with methanol and acetone. The carboxyl modification ratio calculated from the colloid equivalent value of this product was 7.3 mol%.
Met.

Production Example 3 PVA (polymerization degree: 50) was added to a horizontal blender having a capacity of 4 liters.
0, saponification degree 88.2 mol%) 490 parts, NaOH 20
0 parts, 420 parts of a 50% -monochloroacetic acid aqueous solution and 200 parts of isopropyl alcohol were added, and the mixture was stirred at 60 ° C. for 8 hours.

The product obtained was purified with methanol, dried, and analyzed by colloid titration to find that the carboxyl modification rate was 16.2 mol%.

Production Example 4 PVA (polymerization degree: 2,5) was added to a horizontal blender having a capacity of 4 liters.
00, degree of saponification 98.8 mol%) 440 parts, 30% -N
200 parts of an aOH aqueous solution and 484 parts of a 50% -acrylamide aqueous solution were added, followed by stirring at 60 ° C. for 8 hours. Next, 100 parts of 50% -NaOH was added, and hydrolysis was performed at 90 ° C. for 1 hour.

When the obtained powder was analyzed by NMR,
The carboxyl modification rate was 29.3 mol%.

Production Example 5 Production Example 4 except that 250 parts of acrylonitrile was used instead of 484 parts of 50% -acrylamide aqueous solution.
Was performed in the same manner as described above.

When the obtained powder was analyzed by NMR,
The carboxyl modification rate was 37.6 mol%.

Production Example 6 PVA (degree of polymerization: 1,7) was added to a horizontal blender having a capacity of 4 liters.
00, degree of saponification 98.5 mol%) 440 parts, 50% -N
280 parts of aOH aqueous solution and 50% -AMPS aqueous solution 8
28 parts were added and stirred at 80 ° C. for 7 hours.

When the obtained powder was analyzed by NMR,
The modification ratio of the sulfone group was 14.3 mol%.

Production Example 7 PVA (polymerization degree: 5,0) was added to a horizontal blender having a capacity of 4 liters.
00, saponification degree 98.2 mol%) 440 parts, 30% -N
70 parts of an aOH aqueous solution and 284 parts of a 50% -acrylamide aqueous solution were added, and the mixture was stirred at 60 ° C for 4 hours. Then 5
125 parts of 0% -NaOH was added, and the mixture was hydrolyzed at 70 ° C. for 1 hour.

Then, 460 parts of 50% -AMPS sodium salt aqueous solution was added, and the mixture was stirred at 80 ° C. for 4 hours.

When the obtained powder was analyzed by NMR,
The carboxyl modification ratio was 17.3 mol% and the sulfone group modification ratio was 6.5 mol%.

Production Example 8 PVA (polymerization degree: 2,5) was added to a horizontal blender having a capacity of 4 liters.
00, saponification degree 98.8 mol%) 440 parts, 25% -N
30 g of an aOH aqueous solution and 426 g of a 50% acrylamide aqueous solution were added, and the mixture was stirred at 30 ° C. for 7 hours.

The obtained product was purified with methanol and then dried to obtain a powder product. As a result of NMR analysis of this product, the amide group modification rate was 26.1 mol%.

Production Example 9 PVA (polymerization degree: 2,5) was added to a horizontal blender having a volume of 4 liters.
00, saponification degree 98.8 mol%) 440 parts, 25% -N
77 g of aOH aqueous solution and 426 g of 50% acrylamide aqueous solution were added, and the mixture was stirred at 30 ° C. for 4 hours.

Then, 83 g of 48% -NaOH aqueous solution was added, and the mixture was stirred at 70 ° C. for 1 hour.

The product obtained was purified with methanol and then dried to obtain a powder product. As a result of NMR analysis of this product, the amide group modification rate was 12.1 mol% and the carboxyl modification rate was 13.3 mol%.

[Production Example of Component (B)] Production Example 10 To 100 parts of diphenylmethane diisocyanate, a solution prepared by dissolving 38.0 parts of methylethylketoxime in 300 parts of methylethylketone was added, and the reaction was carried out at 50 ° C. for 3 hours to release the components. After confirming that the isocyanate group was 0%, methyl ethyl ketone was removed by distillation to obtain a white powder.

To this product, 420 parts of water was added to prepare a blocked isocyanate aqueous solution having a resin content of 25%.

Production Example 11 A solution prepared by dissolving 57.0 parts of methylethylketoxime in 220 parts of methylethylketone was added to 100 parts of 1,6-hexamethylenediisocyanate, and the mixture was added at 60 ° C. for 2 hours.
After reacting for a period of time and confirming that the free isocyanate group became 0%, 408 parts of water was added to the resin component 2
A 0% blocked isocyanate aqueous solution was prepared.

Production Example 12 To 100 parts of triphenylmethane triisocyanate, 250 parts of methyl ethyl ketone and 6 parts of nonylphenol were added.
After adding a solution in which 0.0 part was dissolved and reacting at 70 ° C. for 2 hours and confirming that the free isocyanate group became 0%, 390 parts of water was added to block the resin content of 20%. A modified isocyanate aqueous solution was prepared.

Production Example 13 Ethylene oxide (EO) based on glycerin,
Propylene oxide (PO) [EO / PO = 30/7
0] to 100 parts of polyaddition product (molecular weight 3,000),
16.8 parts of 1,6-hexamethylene diisocyanate was added and reacted at 90 ° C. for 1 hour to prepare a urethane prepolymer having 3.60% of free isocyanate groups.

Then, a solution prepared by dissolving 9.6 parts of methyl ethyl ketoxime in 50.0 parts of dioxane was added,
After the reaction was carried out at 0 ° C. for 2 hours and it was confirmed that the free isocyanate group had become 0%, 245 parts of water was added to prepare a blocked isocyanate aqueous solution having a resin content of 30%.

Comparative Production Example 1 100 parts of polypropylene glycol (molecular weight 400) was reacted with 84.0 parts of hexamethylenediamine isocyanate to synthesize a prepolymer containing 10.5% of isocyanate groups.

24.0 parts of methylethylketoxime was added to the obtained prepolymer and reacted at 75 ° C. for 80 minutes to obtain a blocked product containing 4.5% of isocyanate groups in the prepolymer.

Next, starch derivative 105 to which 5 mol of ethylene oxide was added per repeating unit was used.
Part, and then 100 parts of dioxane was added and reacted at a system temperature of 90 ° C., after confirming that the isocyanate groups had disappeared, the reaction mixture was diluted with water and a viscous reactive urethane composition having a resin content of 20% was added. I got a thing.

Examples 1 to 9 Component (A) obtained in Production Examples 1 to 9 and Production Examples 10 to 13
Ingredient (B) obtained in the above was blended in the proportions of Table 1 below,
A fiber processing agent of the present invention was obtained.

[0067]

[Table 1] The following evaluations were performed on Examples 1 to 9 shown in Table 1.

Evaluation of Water Absorption In the fiber processing agents obtained in Examples 1 to 9 and Comparative Production Example 1,
Each of the catalysts (Elastron Catalyst-64 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name)) was used at a ratio of 6% with respect to the resin content, and further diluted with water to a resin content of 2%. , A treatment bath was prepared.

The polyester jersey dyeing cloth is dipped in the resulting treatment bath and squeezed uniformly with a mangle (squeeze ratio 100
%), Pre-dried at 100 ° C. for 3 minutes with a baking machine, and then heat-treated at 140 ° C. for 1 minute to measure water absorption. Water absorbency is JIS 10798 method (Pyrex washing)
Was evaluated.

Further, the durability of water absorption by washing was also measured. The water-absorbing durability is determined by using a washing bath containing 2 g / l of a neutral detergent, washing with a household washing machine at a bath ratio of 1:30 at 40 ° C for 60 minutes, and then rinsing at 40 ° C for 60 minutes.
After dehydration and drying, the water absorption was evaluated. Table 2 shows the results.

Comparative Example 1 Formula:

Embedded image A treating bath having the following composition was prepared so that the resin concentration of the treating bath would be 2% by using the modifying agent represented by (100% resin content).

(Treatment bath composition) 2.0 parts of the above modifier 2.0 parts of ammonium persulfate 0.19 parts of water 97.9 parts The same polyester jersey dyeing cloth used in Example 1 was dipped in the above treatment bath. Squeezing (drawing ratio 100%),
After treatment for 5 minutes at a relative humidity of 100% and a temperature of 100 ° C., baking was performed at 140 ° C. for 1 minute, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

[0073]

[Table 2] .

Evaluation of hygroscopicity The fiber processing agents obtained in Examples 1 to 9 and Comparative Production Example 1 were
Each was placed in a Teflon coating sheet with a diameter of 10 cm together with 0.18 g of a catalyst (Elastron Catalyst-64) so that the resin content was 3.0 g, air-dried overnight, and then pre-dried at 60 ° C. for 3 hours, 1 at 140 ° C
Heat treatment was performed for 0 minutes to form a cured film.

After that, the obtained cured film was evaluated for hygroscopicity at 25 ° C. and a humidity of 90%. As the evaluation of the hygroscopicity, the weight change with time of the film was measured at 25 ° C. and a humidity of 90%. Table 3 shows the results.

Comparative Example 2 A cured film was formed in the same manner as above using 3.0 g of the modifier used in Comparative Example 1, 0.15 g of ammonium persulfate and 10 g of water, and the hygroscopicity was measured. The results are also shown in Table 3.

[0077]

[Table 3] .

Evaluation of Moisture Release Property The fiber processing agents obtained in Examples 1 to 9 and Comparative Production Example 1 were treated in the same manner as in the above “Evaluation of Moisture Absorption” to prepare a cured film. The obtained cured film was dipped in a water bath at 25 ° C. and then squeezed so that the drawing ratio was 100%. Then 25
The moisture releasing property at a temperature of 40 ° C and a humidity of 40% was evaluated. As the evaluation of the moisture releasing property, the change in weight of the film with time at 25 ° C. and a humidity of 40% was measured. The results are shown in Table 4.

Comparative Example 3 A cured film was prepared in the same manner as in Comparative Example 2 and immersed in a water bath at 25 ° C. This product was squeezed so that the squeezing ratio was 100%, and the moisture releasing property at 25 ° C. and 40% humidity was measured. The results are shown in Table 4.

[0080]

[Table 4] .

Evaluation of fastness to rubbing The fiber processing agents obtained in Examples 1 to 9 and Comparative Production Example 1 were treated in the same manner as in "Evaluation of water absorption", and the obtained polyester jersey dyeing after resin processing. The rubbing fastness of the cloth was evaluated by the JIS 0849 method. Table 5 shows the results.

Comparative Example 4 The friction fastness of the polyester garment dyed fabric after resin processing obtained in Comparative Example 1 was measured in the same manner. The results are also shown in Table 5.

[0083]

[Table 5] .

[0084]

According to the durable moisture absorptive and desorptive processing method of the present invention as set forth in claims 1 to 3, the water absorptive and desorptive and durable having a significantly superior moisture absorptive and desorptive property as compared with the conventional treatment method. A synthetic fiber product can be obtained. Further, it has an excellent effect of imparting dyeing fastness, and can be applied to a wide range of dyed cloths.

Claims (3)

[Claims] 1. A water-soluble or water-dispersible block having (A) a modified polyvinyl alcohol having an anionic and / or nonionic group, and (B) an isocyanate group blocked with a blocking agent dissociated by heat. A synthetic isocyanate is applied to a synthetic fiber product, and then the synthetic fiber product is heat-treated. 2. The modified polyvinyl alcohol as the component (A) is a modified polyvinyl alcohol obtained by Michael addition of a vinyl compound to polyvinyl alcohol, or partially or completely hydrolyzed after Michael addition. The durable moisture-absorption / desorption processing method for synthetic fibers according to claim 1, which is characterized by being present. 3. The modified polyvinyl alcohol as the component (A) is a modified polyvinyl alcohol obtained by partially or completely hydrolyzing acrylonitrile or acrylamide to polyvinyl alcohol after Michael addition. The durable moisture absorption / desorption processing method for synthetic fibers according to claim 1.