Patent ID: 7445735
Filing Date: 2008-11-04
Classification: B01D,B29B,B29C,B29K,B29L,C08J,C08K,C08L,H01M,Y02E,Y02P,Y10T

Abstract:
1. A process for improving the wet out time of an uncoated microporous membrane comprising the steps of: providing an ultrahigh molecular weight polyethylene (UHMWPE); providing a particulate silica filler; providing a processing plasticizer; mixing UHMWPE, filler and processing plasticizer together to form a mixture, having a weight ratio of filler to UHMWPE of from 1:9 to 15:1 by weight; extruding said mixture to form a sheet; calendering said sheet; extracting all or part of said processing plasticizer from said sheet to produce a matrix comprising UHMWPE and said particulate filler, the filler being distributed throughout said matrix, to produce a microporous matrix sheet; and calendering said microporous matrix sheet to produce a microporous membrane; where said microporous membrane exhibits a reduction in wet out time of 50% or more over said microporous matrix sheet.