Process for producing membranes for use in gas separation

摘要

Method for producing a gas separation membrane comprising a microporous support having provided thereon a non-porous coating layer. The method comprises melt extruding a thermoplastic crystalline polymer under particular melt-extrusion conditions to form a precursor in the form of a hollow fiber or flat film, coating the precursor as a support with a coating substance composed of a natural or synthetic substance capable of forming a polymeric layer which does not form pinholes upon subsequent drawing after solidification to form a coating layer on the surface of the support, and solidifying the coating layer. The support is annealed either before or after the cooling process, and this is followed by cold drawing and heat setting the support to form the gas separation membrane.