POLYOLEFIN-BASED MULTILAYER MICROPOROUS FILM WITH EXCELLENT PHYSICAL PROPERTIES AND HIGH TEMPERATURE STABILITY

摘要

The present invention relates to a polyolefin-based multilayer microporous film which can be used as a battery separator, and to a method for producing the film. The polyolefin-based multilayer microporous film according to the present invention comprises: at least one layer comprising 90 to 100 wt % of polyethylene with a melting point of 130 to 140°C; at least one other layer comprising 20 wt % or more of a heat-resistant resin; and 80 wt % or less of a filler selected from an organic filler, an inorganic filler, and a mixture thereof. The heat-resistant resin is preferably a semicrystalline polymer or an amorphous polymer. The semicrystalline polymer preferably has a degree of crystallinity of 10 to 45 % or a content heat of fusion of 20 to 90 J/g, a crystal melting temperature of 145 to 250°C, and a glass transition temperature of -100 to 90°C. The amorphous polymer has no crystals, and preferably has a glass transition temperature of 90 to 120°C.