Process for the preparation of aromatic polyimide film

摘要

A process for the preparation of an aromatic polyimide film having a surface provided with extremely small sized protrusions having an average diameter of 40 to 2,000 angstroms, the number of protrusions being in the range of 1x104 to 1x109/mm2 is disclosed. The process comprises the steps of coating a coating composition (aromatic polyamic acid solution containing inorganic particles having an average diameter of not larger than 1,000 angstroms) on at least one surface of an aromatic polyimide gel film containing a volatile material in an amount of 10 to 90 wt. % (aromatic polyimide gel film has been obtained by ring closure and imidation of an aromatic polyamic acid in an organic polar oslvent containing a dehydrating agent and a catalyst at a temperature of not higher than 200 DEG C.); drying the obtained film composite at a temperature of 50 DEG to 200 DEG C.; and subjecting the film composite to a heat treatment including heating at a temperature of not lower than 300 DEG C.