Microporous polyolefin composite film with a thermally stable porous layer at high temperature

Abstract

Provided is a microporous polyolefin composite film with a thermally stable porous layer at high temperature, particularly, to the microporous polyolefin composite film in which the thermally stable porous layer at high temperature, which contains organic or inorganic particles and heat-resistant polymer having aromatic ring in main chain and also having a melting temperature or a glass transition temperature of 170 to 500° C., is formed on one surface or both surfaces of a polyolefin microporous film by a phase separation, wherein the composite film with the porous layer has a permeability of 1.5×10 −5 to 20.0×10 −5 Darcy, a meltdown temperature of 160 to 300° C., a MD/TD shrinkage of 1 to 40% at a temperature of 150° C. for 60 minutes.

1 - 6 . (canceled) 
     
     
         7 . A method of manufacturing a microporous polyolefin composite film with a thermally stable porous layer at high temperature, comprising:
 preparing a mixed solution by mixing organic or inorganic particles and a nonsolvent of heat-resistant polymer with a solution in which the heat-resistant polymer is dissolved in a solvent;   coating the mixed solution on one surface or both surfaces of a polyolefin microporous film;   forming the thermally stable porous layer by drying and phase-separating the coated polyolefin microporous film; and   removing the solvent and nonsolvent remained in the thermally stable porous layer by drying or extracting.   
     
     
         8 . The method of manufacturing a microporous polyolefin composite film according to  claim 7 , wherein the nonsovent is selected from a group of water, alcohol, diol, hydrocarbon, ether, glycol, carbonate, ketone, phthalate and a mixture thereof. 
     
     
         9 - 10 . (canceled)