| 摘要 |
PROBLEM TO BE SOLVED: To provide a laminated porous film capable of decreasing fractures on a manufacturing stage by reducing variation of pore size and having shutdown characteristics important to obtain high mechanical strength and safety while having excellent gas permeability contributing to battery performance.SOLUTION: The laminated porous film has at least two layers of a I layer using polypropylene resin as a principal component and a II layer using a resin composition containing polyethylene system resin and styrene based elastomer as a principal component, and has a pin thrust strength of 1.6 N or more, a gas permeability rate at 25°C of 10-1000 seconds/100 mL and a gas permeability rate after heating for 1 minute at 140°C of 50000 seconds/100 mL or more. |
