POLYAMIC ACID, A POLYAMIC ACID SOLUTION, A POLYIMIDE PROTECTION LAYER AND A POLYIMIDE FILM WITH LOW THERMAL EXPANSION COEFFICIENT AND HIGH THERMAL DECOMPOSITION TEMPERATURE

摘要

PURPOSE: A polyamic acid is provided to have excellent thermal stability at the temperature of 500 deg. C or more and to manufacture a substrate or a protection layer with excellent thermal expansion ratio within the temperature range of 50-450 deg. C after molding a film.;CONSTITUTION: A polyamic acid is polymerized from a diamine-based monomer and a dianhydride-based monomer. The aromatic diamine-based monomer comprises 2-(4-aminophenyl)-5-aminobenzoxazole. The aromatic dianhydride-based monomer comprises only a pyromellitic dianhydride or comprises 70 mol% or more of pyromellitic anhydride and 30 mol% or less of 3,3`,4,4`-biphenyltetracarboxylic dianhydride. A polyamic acid solution comprises the polyamic acid and has the viscosity of 50-5,000 poise.;COPYRIGHT KIPO 2013