POLYOLEFIN MULTILAYER MICROPOROUS MEMBRANE AND BATTERY SEPARATOR

摘要

To provide a polyolefin multilayer microporous membrane and a battery separator having excellent mechanical strength and heat resistance. The present invention is a polyolefin multilayer microporous membrane having at least three layers, the membrane comprising a first microporous layer composed of a polyethylene resin containing an ultrahigh molecular weight polyethylene (surface layers) and a second microporous layer composed of a polyolefin rein containing a high-density polyethylene and polypropylene (intermediate layer), wherein (I) the pin puncture strength is at least 25 g/µm, (II) the coefficient of static friction with respect to a metal foil is at least 0.40, and (III) the meltdown temperature is at least 180°C.