Porous polyimide film, and method for producing same

Abstract

A porous polyimide film is obtained from a poly(amic acid) solution containing (a) a poly(amic acid), (b) an organic polar solvent that is a good solvent for the poly(amic acid), and (c) a hydrophobic solvent that is a poor solvent for the poly(amic acid). The poly(amic acid) is obtained by polymerizing an aromatic tetracarboxylic dianhydride containing at least pyromellitic dianhydride and an aromatic diamine containing at least 4,4′-diaminodiphenyl ether. The hydrophobic solvent dissolves in the organic polar solvent, evaporates less readily than the organic polar solvent at the same temperature and pressure, and has a log P in the range of 4.00 or more and 6.00 or less. A method of producing a porous polyimide film includes obtaining a porous polyimide film by drying and then baking a poly(amic acid) solution.

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