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

摘要

The invention provides a porous film having a plurality of connected pores, and a process for its production. The porous film of the invention is a porous film formed from highly heat resistant poly(metaphenylene isophthalamide), and having specific ranges for the open areas and difference between them on both surfaces, as well as specified ranges for the mean pore sizes and porosity on both surfaces. The permeability and impregnation with respect to substances such as air and water, as well as the dynamic strength, are therefore excellent, and the porous film can be used for filters, and for curing resin-impregnated prepregs, multilayer wiring boards, electronic package substrates and the like employing the porous film as a core material.