METHODS OF PRODUCING THE MEMBRANES AND THE USES OF MEMBRANES AS BATTERY SEPARATOR FILMS

摘要

A process of producing a membrane includes extruding diluent and polymer to form an extrudate, the polymer includes a first polyethylene having an Mw<1.0×106, a second polyethylene having an Mw>=1.0×106, and a polypropylene having an Mw>=5.0×105 and a DeltaHm>=80.0 J/g; wherein the sum of the polypropylene having an Mw>=5.0×105 and a DeltaHm>=80.0 J/g and the second polyethylene is >=15.0 wt. % and processing the extrudate into a membrane having a thickness @12.0 mum by stretching the extrudate in at least one planar direction at about 108.0 to 116.0° C. after removing the solvent to a magnification factor of @1.1 and excludes any stretching of the extrudate after removing the solvent at a magnification factor or >1.1 and removing at least a portion of the diluent from the extrudate.