Composite porous membrane and method of producing the same

摘要

A composite porous membrane is a composite porous membrane, wherein a porous membrane B including a heat-resistant resin is laminated on the surface of a polypropylene resin of an outermost layer of a porous membrane A composed of at least one layer, wherein at least one of the outermost layers comprises the polypropylene resin. The composite porous membrane satisfies a particular range of peeling strength at the interface between the porous membrane A and the porous membrane B and a particular range of difference between air resistance of the whole composite porous membrane and air resistance of the porous membrane A, provided that the porous membrane A satisfies a particular range of average pore size and porosity.

主权项

1. A battery separator composite porous membrane comprising a porous membrane B comprising a heat-resistant resin that is free of water-soluble polymers and laminated on a surface of a polypropylene resin of an outermost layer of a porous membrane A comprising at least one layer, wherein the heat-resistant resin being free from water-soluble polymers, wherein at least one of the outermost layers comprises the polypropylene resin, the composite porous membrane satisfying Equations (A) to (D):
0.01 μm≦Average pore size of porous membrane A≦1.0 μm  (A); 30%≦Porosity of porous membrane A≦70%  (B); Peeling strength at interface between porous membrane A and porous membrane B≧1.0 N/25 mm  (C); and 20≦Y−X≦100  (D)wherein X is an air resistance (sec/100 cc Air) of the porous membrane A, and Y is an air resistance (sec/100 cc Air) of the composite porous membrane.