SOLVENT-SOLUBLE 6,6-POLYIMIDE COPOLYMER AND PROCESS FOR PRODUCING THE SAME

摘要

Heat-resistant polyimide copolymers having the following four components: pyromellitic dianhydride (PMDA), 1,4-diaminodiphenyl ether (DADE), biphenyltetracarboxylic dianhydride (BPDA), and 2,4-diaminotoluene (DAT) are provided. In an embodiment the molar ratio of (BPDA):(DADE):(PMDA):(DAT) is 2:2:m:m, in which m is an integer of 3, 4 or 5.