Process for producing polyolefin microporous membrane by thermally induced phase separation

摘要

The present invention discloses a method for preparing a microporous polyolefin film comprising: a step of injecting a composition comprising polyolefin 30 to 60 wt % and a diluent, which can make liquid-liquid phase separation with the polyolefin thermodynamically 40 to 70 wt %, into an extruding machine, and melting and kneading thereof to prepare a single phase me and a step of extruding the melt while conducting liquid-liquid phase separation by passing through a section having the temperature below the liquid-liquid phase separation temperature and forming thereof in the form of a sheet, and a microporous polyolefin film prepared according to the method.