Heat-resistant synthetic resin microporous film and method for producing the same

Abstract

Provided are a heat-resistant synthetic resin microporous film that has both good heat resistance and good mechanical strength and exhibits a suppressed decrease in mechanical strength over time, and a method for producing the heat-resistant synthetic resin microporous film. The heat-resistant synthetic resin microporous film of the present invention includes a synthetic resin microporous film, and a coating layer formed on at least part of the surface of the synthetic resin microporous film and containing a polymer of a polymerizable compound having two or more radically polymerizable functional groups per molecule. The maximum thermal shrinkage rate of the heat-resistant synthetic resin microporous film when heated from 25° C. to 180° C. at a temperature rising rate of 5° C./min is 15% or less. The piercing strength thereof is 0.6 N or more. The rate of retention of the piercing strength after heating at 70° C. for 168 hours is 85% or more.

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