Polylactic acid resin, textile products obtained therefrom, and processes for producing textile products

Abstract

A flat yarn includes a linear polylactic acid resin prepared from lactic acid monomers, wherein at least 95 mol % of the lactic acid is an L-isomer.

1 . A flat yarn comprising a linear polylactic acid resin prepared from lactic acid monomers, wherein at least 95 mol % of the lactic acid is an L-isomer. 
     
     
         2 . The flat yarn according to  claim 1 , wherein the polylactic acid resin contains 0 to 0.5% by weight of lactic acid monomers. 
     
     
         3 . The flat yarn according to  claim 1 , wherein the polylactic acid resin contains 0 to 30 ppm of Sn. 
     
     
         4 . The flat yarn according to  claim 2 , wherein the polylactic acid resin contains 0 to 30 ppm of Sn. 
     
     
         5 . The flat yarn according to  claim 1 , wherein the polylactic acid resin has a relative viscosity in the range of 2.7 to 4.5. 
     
     
         6 . The flat yarn according to  claim 2 , wherein the polylactic acid resin has a relative viscosity in the range of 2.7 to 4.5. 
     
     
         7 . The flat yarn according to  claim 3 , wherein the polylactic acid resin has a relative viscosity in the range of 2.7 to 4.5. 
     
     
         8 . The flat yarn according to  claim 1 , having a tensile strength of 2.6 cN/dtex or more, an elongation of 40.0% or less, and a contraction ratio in hot air at 80° C. for 10 minutes of 5.0% or less. 
     
     
         9 . The flat yarn according to  claim 2 , having a tensile strength of 2.6 cN/dtex or more, an elongation of 40.0% or less, and a contraction ratio in hot air at 80° C. for 10 minutes of 5.0% or less. 
     
     
         10 . The flat yarn according to  claim 3 , having a tensile strength of 2.6 cN/dtex or more, an elongation of 40.0% or less, and a contraction ratio in hot air at 80° C. for 10 minutes of 5.0% or less. 
     
     
         11 . The flat yarn according to  claim 5 , having a tensile strength of 2.6 cN/dtex or more, an elongation of 40.0% or less, and a contraction ratio in hot air at 80° C. for 10 minutes of 5.0% or less. 
     
     
         12 . A process for producing a flat yarn comprising:
 solidifying a film by cooling after melt-extruding a polylactic acid resin according to  claim 1  to form the film, and   hot-drawing the film followed by heat-treatment.   
     
     
         13 . The process for producing a flat yarn according to  claim 12 , wherein the polylactic acid resin contains 0 to 0.5% by weight of lactic acid monomers. 
     
     
         14 . The process for producing a flat yarn according to  claim 12 , wherein the polylactic acid resin contains 0 to 30 ppm of Sn. 
     
     
         15 . The process for producing a flat yarn according to  claim 12 , wherein the polylactic acid resin has a relative viscosity in the range of 2.7 to 4.5. 
     
     
         16 . The process for producing a flat yarn from a polylactic acid resin according to  claim 12 , comprising the steps: melt-extruding a polylactic acid resin to form a film, followed by drawing at a drawing temperature of 80° C. to 130° C. with a draw magnification factor of 4.0 or more. 
     
     
         17 . The process for producing a flat yarn according to  claim 16 , wherein the polylactic acid resin contains 0 to 0.5% by weight of lactic acid monomers. 
     
     
         18 . The process for producing a flat yarn according to  claim 16 , wherein the polylactic acid resin contains 0 to 30 ppm of Sn. 
     
     
         19 . The process for producing a flat yarn according to  claim 16 , wherein the polylactic acid resin has a relative viscosity in the range of 2.7 to 4.5.