| abstract |
An object of the present invention is to provide a polyolefin microporous membrane and the like having a pore structure having a small pore diameter and very excellent air permeability. The present invention relates to a polyolefin microporous film, etc., wherein the polyolefin microporous film has at least a first layer and a second layer, and the polyolefin microporous film is characterized in that the first layer is formed of a first polyolefin resin containing polyethylene. , the second layer is formed of a second polyolefin resin containing polyethylene and polypropylene, and the polyolefin microporous membrane satisfies the following requirements (I) to (II). (I) The gas resistance of the polyolefin microporous membrane is 10-200 seconds/100ml (II) The bubble point pore diameter of the polyolefin microporous membrane is 5-35 nm. |