POLYIMIDE FILM AND A SUBSTRATE FOR A DISPLAY DEVICE USING THE SAME CAPABLE OF IMPROVING DIMENSIONAL STABILITY AT HIGH TEMPERATURE BY HAVING SMALL DIFFERENCE BETWEEN COEFFICIENTS OF THERMAL EXPANSION MEASURED AT 50-500 DEG. CELSIUS AND 580-250 DEG. CELSIUS

摘要

PURPOSE: A polyimide film and a substrate for a display device using the same are provided to improve thermal dimensional stability at high temperature by optimalizing composition ratio and combination of aromatic tetracarboxylic dianhydride and aromatic diamine.;CONSTITUTION: A polyimide film has a difference between coefficients of thermal expansion measured at 50-500 deg. Celsius and 580-250 deg. Celsius of 3ΔHΔ18 according to the thermal transformation interpretation method(TMA-method). The polyimide film is film-formed from polyamic acid solution which is obtained by polycondensing aromatic tetracarboxylic dianhydride and diamine. The aromatic tetracarboxylic dianhydride is formed by blending pyromellitic dianhydride which is represented by chemical formula 1 and dianhydride which contains a flexible group represented by chemical formula 2 at a molar ratio of 7:3-5:5.;COPYRIGHT KIPO 2012