Multilayer Porous Membrane and Process of Manufacture

摘要

A multilayer porous membrane formed of an extrudable polymer is provided. The membrane is formed by co-extruding at least two compositions, each of which comprises a heated porogen and polymer while in contact with each other under conditions to minimize or prevent unstable interfacial flow between extruded layers. In a preferred embodiment, the two compositions are different such that the layers have a different average pore size.

主权项

1. A method comprising:
coextruding two or more polymeric compositions to forth an integral sheet, each of the polymeric compositions comprising a polymer and porogen, wherein the polymer does not form an extrudable polymeric composition with the porogen at about room temperature; phase separating the polymer and porogen in the sheet to form a polymeric gel sheet having two or more regions with differing pore size; and removing the porogen from each region of the gel sheet to form a microporous polymeric membrane having two or more regions with differing pore size.