POROUS MEMBRANE OF POLY(METAPHENYLENE ISOPHTHALAMIDE) AND PROCESS FOR PRODUCING THE SAME

摘要

A porous membrane having a multiplicity of mutuallycommunicating microcells and a process for producing the same.The porous membrane is comprised of highly heat resistantpoly(metaphenylene isophthalamide). In the porous membrane,the open pore ratios of both major surfaces and differencetherebetween fall within specified ranges, and further at bothmajor surfaces, the average pore diameters and porosities fallwithin specified ranges. The porous membrane excels inpermeability for substances such as air and water,impregnation characteristics and mechanical strength, and issuitable for use as core materials of filters, prepregsobtained through impregnation with curable resins, multilayerwiring boards, electronic package boards, etc.