Patent ID: 8796393

Claim:
A production method of a polyhydroxyimide, comprising: adding an acid component that is at least one type of carboxylic acid having a pKa of 0 to 5 to a polyhydroxyimide precursor of Formula (1): wherein X is a tetravalent aliphatic or aromatic group, Y is an organic group containing an aromatic group substituted with at least one OH group, and n is an integer of 1 or more; and heating the resultant mixture to a temperature of 50 to 100° C. to prepare a polyimide of Formula (2): wherein X, Y and n are the same as those defined above the polyhydroxyimide has a weight average molecular weight of 3,000 to 100,000 and the polyhydroxyimide has an imidization rate of 85% or more.