POLYOLEFIN MULTILAYER MICROPOROUS MEMBRANE, METHOD FOR PRODUCING THE SAME, BATTERY SEPARATOR AND BATTERY

摘要

Disclosed is a polyolefin (PO) multilayer microporous membrane which comprises first microporous layers forming the both surface layers and a second microporous layer arranged between the surface layers. The first layers are composed of a first polyolefin (PO) containing (i) a polypropylene (PP) or (ii) a mixture of not less than 50% by mass of a PP and a polyethylene (PE) resin; and the second layer is composed of a second PO containing (i) a mixture of not more than 7% by mass of super high molecular weight PE having an Mw of not less than 1 X 106 and other PE, (ii) a PE other than the super high molecular weight PE, or (iii) a mixture of not more than 50% by mass of a PP and the mixture of (i) or the PE of (ii). The average pore size of the second layer is larger than that of the first layers. ® KIPO & WIPO 2009