Vinyl chloride resin fiber and method for producing same

Abstract

To provide a fiber made of a vinyl chloride resin which is excellent in heat resistance and thus hardly shrinks thermally even at a temperature exceeding 100° C. The fiber obtained by melt-spinning a resin composition comprising a vinyl chloride resin and from 1 to 300 parts by mass of a polyester resin based on 100 parts by mass of the vinyl chloride resin, wherein the vinyl chloride resin has a viscosity average polymerization degree of from 600 to 2,500; the polyester resin is a polylactic acid type resin; and the polyester resin has the melting point of from 100 to 300° C.

1 . A vinyl chloride resin fiber made of a melt-spun fiber of a resin composition comprising a vinyl chloride resin and a polyester resin in an amount of from 1 to 300 parts by mass, based on 100 parts by mass of the vinyl chloride resin. 
   
   
       2 . The vinyl chloride resin fiber according to  claim 1 , wherein the vinyl chloride resin has a viscosity average polymerization degree of from 600 to 2,500. 
   
   
       3 . The vinyl chloride resin fiber according to  claim 1 , wherein the polyester resin has a melting point of from 100 to 300° C. 
   
   
       4 . The vinyl chloride resin fiber according to  claim 1 , wherein the polyester resin is a polylactic acid type resin. 
   
   
       5 . The vinyl chloride resin fiber according to  claim 1 , which has a fineness of monofilament of from 1 to 200 decitex. 
   
   
       6 . Artificial hair made of the vinyl chloride resin fiber as defined in  claim 1 . 
   
   
       7 . A process for producing a vinyl chloride resin fiber comprising the sequential steps:
 (a) mixing a resin composition comprising a vinyl chloride resin and a polyester resin;   (b) melt-spinning the mixed resin composition from a spinneret at a resin temperature of from 150 to 200° C.;   (c) stretching the melt-spun fiber in an atmosphere of air held at a temperature of from 30 to 150° C. to have a stretching ratio of from 2 to 20 times as much; and   (d) subjecting the stretched fiber to a thermal relaxing treatment in an atmosphere of air held at a temperature of from 80 to 200° C. until the entire length of the fiber becomes from 99.8 to 50% of the length before the treatment.   
   
   
       8 . The process for producing a vinyl chloride resin fiber according to  claim 7 , wherein the sectional area per nozzle hole used in the melt-spinning step is at most 3 mm 2 .