MICROPOROUS MEMBRANE AND METHOD FOR PROVIDING THE SAME

摘要

A method of producing a microporous membrane comprising the steps of: extruding a polymer at a temperature of from (polymer melting point +10° C.) to (polymer melting point +100° C.); drawing the extruded polymer at a rate of 5~120 m/min in 10~150° C. to obtain a polymer film; annealing the polymer film at a temperature of from (polymer melting point -100° C.) to (polymer melting point -5° C.) for 10 seconds to 1 hour; irradiating both surfaces of the annealed polymer film with an ion-particle amount of 102~1020 ion/cm2 energized at 10-2~107 KeV, at an irradiating distance of 5~100 cm under a vacuum of 10-2~10-[torr; cold stretching the irradiated polymer film at a temperature of from -20° C. to (polymer melting point -40° C.); hot stretching the cold stretched polymer film at a temperature of from (polymer melting point -40° C.) to (polymer melting point -5° C.); and heat setting the hot stretched polymer film at a temperature of from (polymer melting point -80° C.) to (polymer melting point -5° C.).