| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyolefin fine porous film excellent in smoothness and compression characteristics. SOLUTION: A polyolefin composition comprises a polypropylene and a polyethylene as essential ingredients, wherein (1) the polypropylene comprises a powdered polypropylene as essential ingredients, and/or (2) the polypropylene has a MFR of 2.0 or below and is contained a content of 20 wt.% or below, and the polyethylene has a weight average molecular weight/number average molecular weight of 8-100. The polyolefin composition provides a polyolefin fine porous film in which (a) film thickness variation ratio is 1.5 or below, and (b) a ratio (A)/(B) of the air permeability (A) after pressing for 60 seconds with a load of 3 MPa at a temperature of 100 deg.C and the air permeability (B) before the press is 4.0 or below.
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