Modacrylic shrinkable fiber and method for manufacturing the same

1. A modacrylic shrinkable fiber manufactured from a spinning solution comprising a polymer composition obtained by mixing

50 to 99 parts by weight of a polymer (A) comprising 40 wt % to 80 wt % of acrylonitrile, 20 wt % to 60 wt % of a halogen-containing monomer and 0 wt % to 5 wt % of a sulfonic-acid-containing monomer, and

1 to 50 parts by weight of a polymer (B) comprising 5 wt % to 70 wt % of acrylonitrile, 20 wt % to 94 wt % of an acrylic ester and 16 wt % to 40 wt % of a sulfonic-acid-containing monomer comprising a methallylsulfonic acid or metal salts thereof or amine salts thereof, and no halogen-containing monomer; a total amount of the polymer (A) and the polymer (B) being 100 parts by weight;

wherein the modacrylic shrinkable fiber is capable of being dyed in deep colors at a temperature equal to or lower than 80° C. and achieving a post-dyeing shrinkage ratio treated in dry heat at 130° C. for 5 minutes of equal to or larger than 20%.

2. The modacrylic shrinkable fiber according to claim 1 , wherein the methallylsulfonic acid or the metal salts thereof or the amine salts thereof in the polymer (B) is sodium methallylsulfonate.

3. The modacrylic shrinkable fiber according to claim 1 , which comprises 0.01 wt % to 10 wt % of sodium methallylsulfonate in the polymer (B).

4. The modacrylic shrinkable fiber according to claim 1 , which comprises 0.1 wt % to 3 wt % of sodium methallylsulfonate in the polymer (B).

5. The modacrylic shrinkable fiber according to claim 1 , wherein a relative saturation value at 70° C. is at least 0.8.

6. The modacrylic shrinkable fiber according to claim 1 , wherein the polymer (A) and the polymer (B) are incompatible with each other and have a sea-island structure with the polymer (A) being the sea and the polymer (B) being the islands.

7. A method for manufacturing a modacrylic shrinkable fiber, wherein

spinning is performed using a spinning solution obtained by dissolving in acetone

50 to 99 parts by weight of a polymer (A) comprising 40 wt % to 80 wt % of acrylonitrile, 20 wt % to 60 wt % of a halogen-containing monomer and 0 wt % to 5 wt % of a sulfonic-acid-containing monomer, and

1 to 50 parts by weight of a polymer (B) comprising 5 wt % to 70 wt % of acrylonitrile, 20 wt % to 94 wt % of an acrylic ester and 16 wt % to 40 wt % of a sulfonic-acid-containing monomer comprising a methallylsulfonic acid or metal salts thereof or amine salts thereof, and no halogen-containing monomer; a total amount of the polymer (A) and the polymer (B) being 100 parts by weight; drawing is performed, and

dyeing is performed at a temperature equal to or lower than 80° C., thus obtaining a modacrylic shrinkable fiber having a post-dyeing shrinkage ratio being treated in dry heat at 130° C. for 5 minutes of equal to or larger than 20%.

8. The method for manufacturing a modacrylic shrinkable fiber according to claim 7 , wherein water is dissolved further in the acetone.

9. The modacrylic shrinkable fiber according to claim 1 , wherein 1 wt % to 40 wt % of the sulfonic-acid-containing monomer comprising the methallylsulfonic acid or the metal salts thereof or the amine salts thereof in the polymer (B) comprises

(a) at least one sulfonic-acid-containing monomer selected from the group consisting of a methallylsulfonic acid, metal salts thereof and amine salts thereof and

(b) at least one sulfonic-acid-containing monomer selected from the group consisting of an allylsulfonic acid, a styrenesulfonic acid, an isoprenesulfonic acid and a 2-acrylamido-2-methylpropanesulfonic acid, and metal salts thereof and amine salts thereof,

the content of (a) is 0.01 wt % to 10 wt %, and

the content of (a)+(b) is 1 wt % to 40 wt %.

10. The modacrylic shrinkable fiber according to claim 1 , wherein 1 wt % to 40 wt % of the sulfonic-acid-containing monomer comprising the methallylsulfonic acid or the metal salts thereof or the amine salts thereof in the polymer (B) comprises

(a) 0.01 wt % to 10 wt % of a methallylsulfonic acid, and

(b) 15 wt % to 30 wt % of a 2-acrylamido-2-methlylproanesulfonic acid.

11. The method for manufacturing a modacrylic shrinkable fiber according to claim 7 , wherein 1 wt % to 40 wt % of the sulfonic-acid-containing monomer comprising the methallylsulfonic acid or the metal salts thereof or the amine salts thereof in the polymer (B) comprises

(a) at least one sulfonic-acid-containing monomer selected from the group consisting of a methallylsulfonic acid, metal salts thereof and amine salts thereof, and

(b) at least one sulfonic-acid-containing monomer selected from the group consisting of an allylsulfonic acid, a styrenesulfonic acid, an isoprenesulfonic acid and a 2-acrylamido-2-methylpropanesulfonic acid, and metal salts thereof and amine salts thereof,

the content of (a) is 0.01 wt % to 10 wt %, and

the content of (a)+(b) is 1 wt % to 40 wt %.

12. The method for manufacturing a modacrylic shrinkable fiber according to claim 7 , wherein 1 wt % to 40 wt % of the sulfonic-acid-containing monomer comprising the methallylsulfonic acid or the metal salts thereof or the amine salts thereof in the polymer (B) comprises

(a) 0.01 wt % to 10 wt % of a methallylsulfonic acid, and

(b) 15 wt % to 30 wt % of a 2-acrylamido-2-methylpropanesulfonic acid.