HIGH ORIENTED POLYIMIDE FILM, MANUFACTURING METHOD THEREOF AND SUBSTRATE FOR FLEXIBLE DISPLAY USING THE SAME

摘要

PURPOSE: An anisotropic polyimide oriented film is provided to impart low thermal expansion coefficient of 20 ppm/°C or lower by controlling orientation in surface of a polyimide film, thereby suitable for a flexible display substrate. CONSTITUTION: An anisotropic polyimide oriented irradiates with light a polyimide film containing a polymer liquid crystal material, which has polyimide as a backbone, a photo-crosslinkable group in side chain so that orientation in surface is increased. A manufacturing method of synthesizing polyamic acid solution comprises a step of synthesizing polyamic acid solution through condensation polymerizing aromatic tetracarboxylic dianhydride, and aromatic diamine; a step of obtaining a blending solution by adding a polymer with 10-20 weight% of photo-crosslinkable group into the polyamic acid solution; a step of manufacturing a film by imidizing the blending solution; and a step of irradiating the film with light, and heat-treating the same.