| abstract |
A polyethylene-based resin as a main component, and (a) the shutdown temperature (temperature at which the air permeability measured while heating at a heating rate of 5 ° C./min reached 1 × 10 5 sec / 1OOcm 3 ) is 135 ° C. or less. (B) The rate of change in air permeability (gradient in air permeability of 1 × 10 4 sec / 1OOcm 3 of the curve indicating the dependence on the temperature of the air permeability) is 1 × 10 4 sec / 1OOcm 3 / ° C. (C) polyolefin microporous, characterized in that (c) the meltdown temperature (temperature at which the air permeability measured while the temperature is further increased after reaching the shutdown temperature is 1 × 10 5 sec / 1OOcm 3 again) is 150 ° C. or more. Provide a membrane.n n n n Polyolefin, Fine, Porous Membrane, Separator, Battery |