Patent ID: 7208200
Filing Date: 2007-04-24
Classification: B01D,B29C,B29K,B29L,Y10T

Abstract:
1. A process for forming an integral, unsupported, multizone microporous membrane having at least two zones, comprising the acts of: operatively positioning relative to a continuously moving coating surface at least one polymer applying apparatus having at least two polymer dispensing outlets in chambers with a front wall and a back wall and a separating wall between the front wall and the back wall defining the volumes of the chambers; co-casting polymer from each of the polymer dispensing outlets onto the continuously moving coating surface so as to create a multiple layer polymer coating on the coating surface, wherein the polymer is dispensed from the chambers by gravity, fluid pressure, or pumping; subjecting the multiple polymer layer coating to a phase separation procedure so as to form a wet multizone microporous membrane; and separating the wet multizone microporous membrane from the continuously moving coating surface at some point prior to complete drying of the membrane.