Patent ID: 8513373

Claim:
A method for producing a polyimide film containing a non-thermoplastic polyimide having a block component derived from a thermoplastic polyimide by a process at least comprising the steps of (A) forming in an organic polar solvent a prepolymer from a diamine component (a) and an acid dianhydride component (b) in a molar amount that is less than that of the diamine component (a), the prepolymer having an amino group at one or each end; (B) synthesizing a polyimide precursor solution from the prepolymer obtained in step (A), an acid dianhydride component (c), and a diamine component (d) in such amounts that make up equimolar amounts of acid dianhydride component and diamine component in the overall process; (C) flow-casting a film formation dope solution containing the polyimide precursor solution and subjecting the film formation dope solution to chemical and/or thermal imidization, wherein the diamine component (a) and the acid dianhydride component (h) used in step (A) are so selected that a polyimide prepared from equimolar reaction of the diamine component (a) and the acid dianhydride component (b) is thermoplastic, and wherein the polyimide precursor obtained in step (B) is a precursor of the non-thermoplastic polyimide.