Polyester yarn and production method thereof

Abstract

Disclosed is a polyester yarn which can be used in a fabric for an airbag. A content of one or more inorganic fillers selected from the group consisting of TiO 2 , SiO 2 , and BaSO 4 is 200 ppm or less, a breaking elongation is 15% or more, a dry shirinkage rate is 3% or more, and the sum of the breaking elongation and the dry shirinkage rate is 20% or more, a production method thereof, and a fabric for an airbag produced therefrom. The polyester yarn has remarkably reduced stiffness and excellent mechanical properties of high strength, high elongation, and high shirinkage.

1 . A polyester yarn, wherein the content of one or more inorganic fillers selected from the group consisting of TiO 2 , SiO 2 , and BaSO 4  is 200 ppm or less, a breaking elongation is 15% or more, a dry shirinkage rate is 3% or more, and the sum of the breaking elongation and the dry shirinkage rate is 20% or more. 
     
     
         2 . The polyester yarn according to  claim 1 , wherein an intrinsic viscosity is 0.8 dl/g or more. 
     
     
         3 . The polyester yarn according to  claim 1 , wherein a crystallinity is 42% to 52% 
     
     
         4 . The polyester yarn according to  claim 1 , wherein a tenacity is 9.0 g/d or more and a toughness value is 30×10 −1  g/d or more. 
     
     
         5 . The polyester yarn according to  claim 1 , wherein the yarn has a single yarn fineness of 0.5 to 20 denier. 
     
     
         6 . The polyester yarn according to  claim 1 , wherein the yarn has a total fineness of 200 to 1,000 denier. 
     
     
         7 . The polyester yarn according to  claim 1 , wherein the yarn has the number of filaments of 50 to 240. 
     
     
         8 . A method for producing the polyester yarn according to  claim 1 , comprising the steps of:
 melt-spinning a polyester polymer having a content of one or more inorganic fillers selected from the group consisting of TiO 2 , SiO 2 , and BaSO 4  of 200 ppm or less at 270 to 300° C. so as to prepare an undrawn polyester yarn, and   drawing the undrawn polyester yarn.   
     
     
         9 . The method according to  claim 8 , wherein the polyester polymer includes 70 mol % or more of poly(ethylene terephthalate). 
     
     
         10 . The method according to  claim 8 , wherein an intrinsic viscosity of the polyester polymer is 0.85 dl/g or more. 
     
     
         11 . The method according to  claim 8 , wherein the drawing process is carried out at a draw ratio of 5.0 to 6.0. 
     
     
         12 . The method according to  claim 8 , wherein a function value of the following Calculation Formula 1, based on the content of the inorganic filler in the polyester polymer, the intrinsic viscosity of the polyester polymer, and the draw ratio during the drawing process, is 50 or more and 190 or less:
   50≦ a   1   +a   2   +a   3 ≦190  [Calculation Formula 1]
   wherein   a 1  is the absolute value of the inorganic filler content (ppm) in the polyester polymer,   a 2  is the value resulting from multiplying the absolute value of the intrinsic viscosity (dl/g) of the polyester polymer by 10, and   a 3  is the value resulting from multiplying the draw ratio in the drawing process by 10.   
     
     
         13 . The method according to  claim 8 , wherein the difference in the intrinsic viscosity between the polyester polymer and the yarn is 0.5 dl/g or less. 
     
     
         14 . The method according to  claim 8 , wherein the spinning process is carried out at a spinning speed of 300 m/min to 1,000 m/min. 
     
     
         15 . The method according to  claim 8 , wherein the drawing process is carried out after passing the undrawn polyester yarn through a godet roller with an oil pickup amount of 0.2% to 2.0%. 
     
     
         16 . The method according to  claim 8 , further comprising the step of performing a relaxation process at a relaxation ratio of 1% to 7% after the step of drawing the undrawn yarn. 
     
     
         17 . A polyester fabric for an airbag, comprising the polyester yarn according to  claim 1 . 
     
     
         18 . The polyester fabric for an airbag according to  claim 17 , wherein the tear strength of the fabric measured according to the ASTM D 2261 method (standard of the American Society for Testing and Materials) is 20 kgf or more. 
     
     
         19 . The polyester fabric for an airbag according to  claim 17 , wherein the edgecomb resistance of the fabric measured according to the ASTM D 6479 method (standard of the American Society for Testing and Materials) at room temperature (25° C.) is 350 N or more.