High-strength polyethylene terephthalate yarn and method for producing the same

Abstract

Disclosed are a PET fiber having an intrinsic viscosity of 1.1 dl/g or higher and a tensile strength of 10 g/d or higher, and a manufacturing method therefor. The manufacturing method includes the steps of: melting a polyethylene terephthalate chip having an intrinsic viscosity of 1.4 to 1.7 dl/g to prepare a spinning melt; discharging the spinning melt through a nozzle of a spinning pack; heating the spinning melt just before being discharged from the nozzle by means of a heat source of 300 to 500° C. located immediately below the nozzle; converging a plurality of filaments formed by the discharging to form a multifilament; and drawing the multifilament, wherein a temperature of the spinning pack is maintained at 280 to 305° C.

1 . A polyethylene terephthalate yarn comprising
 100 to 500 filaments each having fineness of 2 to 5 denier,   wherein the PET yarn has an intrinsic viscosity of 1.1 dl/g or more and a tensile strength of 10 g/d or more.   
     
     
         2 . The polyethylene terephthalate yarn of  claim 1 , wherein the PET yarn has an intrinsic viscosity of 1.1 to 1.25 dl/g and a tensile strength of 10 to 10.6 g/d. 
     
     
         3 . The polyethylene terephthalate yarn of  claim 1 , wherein the PET yarn has elongation of 3 to 6% at a 4.5 g/d load and dry heat shrinkage of 7 to 12%. 
     
     
         4 . The polyethylene terephthalate yarn of  claim 1 , wherein the PET yarn has elongation at break of 13 to 14%. 
     
     
         5 . The polyethylene terephthalate yarn of  claim 4 , wherein the PET yarn has elongation at break of 13.4 to 13.9%. 
     
     
         6 . A method for producing a polyethylene terephthalate yarn comprising the steps of:
 melting a polyethylene terephthalate chip having an intrinsic viscosity of 1.4 to 1.7 dl/g to prepare a spinning melt;   discharging the spinning melt through a nozzle of a spinning pack;   heating the spinning melt just before being discharged from the nozzle by means of a heat source of 300 to 500° C. located immediately below the nozzle;   converging a plurality of filaments formed by the discharging to form a multifilament; and   drawing the multifilament,   wherein a temperature of the spinning pack is maintained at 280 to 305° C.   
     
     
         7 . The method for producing a polyethylene terephthalate yarn according to  claim 6 , wherein a speed after drawing of 4000 to 6200 m/min and a draw ratio of 1.9 to 2.5 are applied. 
     
     
         8 . The method for producing a polyethylene terephthalate yarn according to  claim 6 , wherein the distance between the nozzle and the heat source is 5 to 50 mm. 
     
     
         9 . The method for producing a polyethylene terephthalate yarn according to  claim 8 , wherein the temperature of the heat source is higher than the temperature of the spinning pack. 
     
     
         10 . The method for producing a polyethylene terephthalate yarn according to  claim 9 , wherein the heat source includes a hot wire. 
     
     
         11 . The method for producing a polyethylene terephthalate yarn according to  claim 9 , wherein
 the heat source includes a plurality of hot wires, and   the hot wires are respectively arranged between the filaments so as to not hinder the movement of the filaments.   
     
     
         12 . The method for producing a polyethylene terephthalate yarn according to  claim 11 , wherein
 the hot wires are arranged at equal intervals, and   each of the hot wires is arranged to be parallel to the lower surface of the nozzle.   
     
     
         13 . The method for producing a polyethylene terephthalate yarn according to  claim 6 , wherein the discharging step is performed under a discharge pressure of 2400 psi or less.