| 摘要 |
A porous multi-layer film favorably employable as a separator film for a nonaqueous electric battery comprises at least three united polyolefin layers, in which at least one polyolefin layer is a polyethylene layer and at least one polyolefin layer is a polypropylene layer which is placed in contact with the polyethylene layer. The polyolefin layers are combined to form a united structure with a peel strength of at least 3 g/15 mm and has a pore volume of 30-80%, a maximum pore size of 0.02-2 mu m, a shutdown temperature of 135 DEG -140 DEG C., and a thermal durability to maintain the shutdown condition up to at least 180 DEG C.
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