| 摘要 |
PROBLEM TO BE SOLVED: To provide a separator for electric power storage device use which is made of a porous polyolefin film and has a shutdown property and excellent heat resistance.SOLUTION: A porous polyolefin film has a melting point of 155°C or higher, a pre-thermal treatment air infiltration resistance of 400 seconds/100 ml or smaller, and an air infiltration resistance of 1,000 seconds/100 ml or larger after a one-minute thermal treatment at 140°C. The porous polyolefin film includes 10 mass% or less of polyethylene, and 3 mass% or more of low-melting point polypropylene having a melting point of 130-160°C to a total of 100 mass% of the porous polyolefin film. |
