TRANSPARENT POLYIMIDE WITH LOW COEFFICIENT OF THERMAL EXPANSION

摘要

PURPOSE: A polyimide film is provided to be useful for a transparent conductive film, a TFT substrate, a flexible printed circuit board as the polyimide film is colorless and transparent and has an excellent mechanical property and thermal stability. CONSTITUTION: Polyimide is produced by polymerizing dianhydride monomer and diamine monomer. The diamine monomer is a mixture of 2,2 '-bis (trifluoromethyl)benzidine and 4,4' -diaminodiphenyl sulfone. The mole ratio of dianhydride monomer : diamine monomer is 1:1. The mole ratio of dianhydride monomer : 2,2'-bis (trifluoromethyl)benzidine : 4,4'-diaminodiphenyl sulfone is 1:0.2-0.8:0.2-0.2.