Polytrimethylene terephthalate fiber and method for producing same

Abstract

The polytrimethylene terephthalate fiber satisfies the requirements that a peak value of the thermal stress of the fiber be present in the temperature range of from 40 to 100° C., the peak value be 0.1 to 0.8 cN/dtex, and the fiber have an elongation at break of 60 to 200%. The method for producing a fiber includes melting and solidifying polytrimethylene terephthalate, and then winding up the solidified polytrimethylene terephthalate at a winding speed of 1,000 m/minute or more, and heating the resultant polytrimethylene terephthalate using a heated roller at a temperature which is ±20° C. of the glass transition point of polytrimethylene terephthalate, and drawing the heated polytrimethylene terephthalate at a draw ratio of 1.0 to 2.0 times, and further winding the drawn polytrimethylene terephthalate round a heated roller at 50 to 150° C. and then winding up the resultant polytrimethylene terephthalate at a rate of 2,000 to 4,800 m/minute.

1 . A fiber of polytrimethylene terephthalate, which is comprised of trimethylene terephthalate repeating units in an amount of 90 mol % or more, the polytrimethylene terephthalate fiber satisfying all the following requirements (A) to (C):
 (A) that, in the temperature-thermal stress curve of the fiber, a peak value of the thermal stress be present in the temperature range of from 40 to 100° C.;   (B) that the peak value of the thermal stress in the requirement (A) be 0.1 to 0.8 cN/dtex; and   (C) that the fiber has an elongation at break of 60 to 200%.   
     
     
         2 . The polytrimethylene terephthalate fiber according to  claim 1 , which has the lowest modulus of 0.1 to 3 cN/dtex at an elongation of 10 to 30% of the fiber. 
     
     
         3 . The polytrimethylene terephthalate fiber according to  claim 1 , which has a birefringence (Δn) of 0.03 to 0.08 and a specific gravity of 1.319 to 1.340. 
     
     
         4 . A method for producing a polytrimethylene terephthalate fiber, comprising melting and solidifying polytrimethylene terephthalate, which is comprised of trimethylene terephthalate repeating units in an amount of 90 mol % or more, and then winding up the solidified polytrimethylene terephthalate at a winding speed of 1,000 m/minute or more and subsequently, heating the resultant polytrimethylene terephthalate using a heated roller at a temperature of the glass transition point of polytrimethylene terephthalate ±20° C., and then drawing the heated polytrimethylene terephthalate at a draw ratio of 1.0 to 2.0 times, and further winding the drawn polytrimethylene terephthalate round a heated roller at 50 to 150° C., and then winding up the resultant polytrimethylene terephthalate at a speed of 2,000 to 4,800 m/minute. 
     
     
         5 . A textured yarn which is obtained using the polytrimethylene terephthalate fiber according to  claim 1 . 
     
     
         6 . The textured yarn according to  claim 5 , which is a false twisted textured yarn. 
     
     
         7 . A method for producing the textured yarn according to  claim 5 . 
     
     
         8 . A textured yarn which is obtained using the polytrimethylene terephthalate fiber according to  claim 2 . 
     
     
         9 . The textured yarn according to  claim 8 , which is a false twisted textured yarn. 
     
     
         10 . A method for producing the textured yarn according to  claim 8 . 
     
     
         11 . A textured yarn which is obtained using the polytrimethylene terephthalate fiber according to  claim 3 . 
     
     
         12 . The textured yarn according to  claim 11 , which is a false twisted textured yarn. 
     
     
         13 . A method for producing the textured yarn according to  claim 11 .