Polyethylene yarn, method for manufacturing the same, and skin cooling fabric comprising the same

Abstract

Disclosed is a polyethylene yarn which enables the manufacture of a skin cooling fabric having dimensional stability and having improved weavability which enables the manufacture of a skin cooling fabric capable of providing a user with a soft tactile sensation as well as a cooling sensation, a method for manufacturing the same, and a skin cooling fabric including the same. The polyethylene yarn has a shrinkage stress at 70° C. and 100° C. of 0.005 to 0.075 g/d, respectively. Also, the polyethylene yarn has a “dry thermal shrinkage rate at 70° C.” of 0.1 to 0.5%, a “dry thermal shrinkage rate at 100° C.” of 0.5 to 1.5%, and a “wet thermal shrinkage rate at 100° C.” of 0.1 to 1%.

1 . A polyethylene yarn, wherein
 (i) in a graph showing a shrinkage stress due to the temperature rise, obtained under the conditions of an initial load of 0.1 g/d and a temperature rising rate of 2.5° C./s, a shrinkage stress at 70° C., and a shrinkage stress at 100° C., were 0.005 to 0.075 g/d, respectively,   (ii) a dry thermal shrinkage rate after being placed in air at 70° C. for 15 minutes under a load of 0.1 g/d is 0.1 to 0.5%,   (iii) a dry thermal shrinkage rate after being placed in air at 100° C. for 15 minutes under a load of 0.1 g/d is 0.5 to 1.5%, and   (iv) a wet thermal shrinkage rate after being immersed in hot water at 100° C. for 30 minutes is 0.1 to 1%.   
     
     
         2 . The polyethylene yarn of  claim 1 , wherein
 the polyethylene yarn has an interlacing number of 10 to 40 ea/m.   
     
     
         3 . The polyethylene yarn of  claim 1 , wherein
 an oil pick-up (OPU) of the polyethylene yarn is 1 to 4 wt %.   
     
     
         4 . The polyethylene yarn of  claim 1 , wherein
 the polyethylene yarn is a twisted yarn having a twist number of 50 to 300 TPM (twists per meter) in the Z direction.   
     
     
         5 . The polyethylene yarn of  claim 1 , wherein
 the polyethylene yarn has tensile strength of more than 4 g/d and 6 g/d or less, a tensile modulus of 15 to 80 g/d, elongation at break of 14 to 55%, and crystallinity of 60 to 85%.   
     
     
         6 . The polyethylene yarn of  claim 1 , wherein
 the polyethylene yarn has a weight average molecular weight (Mw) of 50,000 to 99,000 g/mol.   
     
     
         7 . The polyethylene yarn of  claim 1 , wherein
 the polyethylene yarn has total fineness of 75 to 450 denier, and   the polyethylene yarn includes a plurality of filaments each having a DPF (denier per filament) of 1 to 5 denier.   
     
     
         8 . The polyethylene yarn of  claim 1 , wherein
 the polyethylene yarn has a circular cross-section.   
     
     
         9 . A skin cooling fabric comprising the polyethylene yarns of 1 as a weft yarn and a warp yarn, wherein
 dry thermal shrinkage rates in the directions of warp and weft after heat treatment in a chamber at 70° C. for 15 minutes are 0.1 to 1.0%, respectively,   dry thermal shrinkage rates in the directions of warp and weft after heat treatment in a chamber at 100° C. for 15 minutes are 0.3 to 1.2%, respectively, and   wet thermal shrinkage rates in the directions of warp and weft after immersion in hot water at 100° C. for 30 minutes are 0.2 to 1.0%, respectively.   
     
     
         10 . The skin cooling fabric of  claim 9 , wherein
 the skin cooling fabric at 20° C. has a thickness direction thermal conductivity of 0.0001 W/cm·° C., a thickness direction heat transfer coefficient of 0.001 W/cm 2 ·° C., and a contact cold sensation (Q max ) of 0.1 W/cm 2  or more.   
     
     
         11 . The skin cooling fabric of  claim 9 , wherein
 the area density of the skin cooling fabric is 75 to 800 g/m 2 .   
     
     
         12 . A method for manufacturing a polyethylene yarn comprising the steps of:
 melting a polyethylene having a density of 0.941 to 0.965 g/cm 3 , a weight average molecular weight (Mw) of 50,000 to 99,000 g/mol, and a melt index (MI) (at 190° C.) of 6 to 21 g/10 min;   extruding the molten polyethylene through a spinneret having a plurality of spinning holes;   cooling a plurality of filaments formed when the molten polyethylene is discharged from the holes of the spinneret;   drawing a multifilament comprised of the cooled filaments using a multistage drawing part including a series of godet rollers; and   winding the drawn multifilament with a winder,   wherein an overfeed ratio defined by Equation 1 below is 6 to 10%:
   OFR (%)=100−[( V   1   /N   2 )×100]  [Equation 1]
 
   in Equation 1, OFR is the overfeed ratio, V 1  is the speed of the last godet roller of the multistage drawing part, and V 2  is the speed of the winder.