Process for producing core/sheath conjugate elastomer fiber

Abstract

The present invention provides a process for producing a conjugate fiber that is excellent in strength, stretch elasticity, and transparency. The process includes a step (1) in which an elastomer resin (A) having stretching elasticity and an elastomer resin (B) having stretch elasticity, a permanent elongation of 25-70%, and a tensile elongation of 100-800% are separately melted and subjected to conjugate spinning using a conjugate spinneret having two nozzles so that the elastomer resin (A) forms a core and the elastomer resin (B) form a sheath; a step (2) in which the fiber obtained by composite spinning in the step (1) is heat-treated; and a step (3) in which the fiber heat-treated in the step (2) is stretched.

1 . A process of producing a conjugate fiber comprising: (1) separately melting an elastomer resin (A) having stretch elasticity, and an elastomer resin (B) having stretch elasticity, a permanent elongation of 25 to 70%, and a tensile elongation of 100 to 800%, and subjecting the molten resins to conjugate spinning using a conjugate spinneret having two nozzles to form a bicomponent fiber comprising the elastomer resin (A) as a core and the elastomer resin (B) as a sheath; (2) heat-treating the fiber obtained by conjugate spinning in step (1); and (3) stretching the fiber heat-treated in step (2). 
   
   
       2 . A process according to  claim 1 , wherein the heat treatment temperature in step (2) is 40 to 80° C. 
   
   
       3 . A process according to  claim 1 , wherein the fiber is stretched to 1.25 to 4 times its original length in step (3). 
   
   
       4 . A process according to  claim 1 , wherein the fiber is stretched in step (3) while heated at a temperature not lower than the heat treatment temperature of step (2). 
   
   
       5 . A process according to  claim 1 , wherein the elastomer resin (A) is a polyurethane elastomer. 
   
   
       6 . A process according to  claim 1 , wherein the elastomer resin (B) is a polyester-based elastomer and/or a polyamide-based elastomer. 
   
   
       7 . A process according to  claim 1 , wherein the elastomer resin (B) contains inorganic fine particles. 
   
   
       8 . A process according to  claim 1 , wherein the core and the sheath of the conjugate fiber have an eccentric circle or concentric circle configuration. 
   
   
       9 . A conjugate fiber produced by the process of any one of  claims 1  to  8 . 
   
   
       10 . A stretch clothing comprising the conjugate fiber of  claim 9 . 
   
   
       11 . A conjugate fiber comprising an elastomer resin (A) having stretch elasticity, and an elastomer resin (B) having stretch elasticity, a permanent elongation of 25 to 70%, and a tensile elongation of 100 to 800%; the conjugate fiber being a sheath-core fiber in which the core comprises the elastomer resin (A), and the sheath comprises the elastomer resin (B), and the area ratio of the core to the sheath in the cross-section of the fiber is in the range of 95:5 to 40:60.