Patent ID: 8053082

Claim:
An adhesion-enhanced polyimide film which comprises a core layer composed of a polyimide (A) having high rigidity and a low linear expansion coefficient, at least one side of which has a thin-layer with a thickness of 0.05 to 1 μm formed by heating a coated layer comprising a) a heat-resistant surface treatment agent selected from N-[β-(phenylamino)-ethyl]-y-aminopropyl-triethoxysilane, N-phenyl-y-aminopropyl-triethoxysilane and y-phenylaminopropyl-triethoxysilane and b) a polyimide precursor obtained from two components consisting of i) at least one aromatic tetracarboxylic dianhydride selected from the group consisting of 2,3,3′,4′-biphenyltetracarboxylic dianhydride and 2,2′,3,3′-biphenyltetracarboxylic dianhydride and ii) at least one aromatic diamine selected from, the group consisting of p-phenylenediamine and 4,4′-diaminodiphenyl ether, which yields a highly heat-resistant amorphous polyimide (B), wherein the polyimide film is obtained by heating at a maximum heating temperature of 370-575° C. a multilayer self-supporting film obtained by coating an organic solvent solution comprising the heat-resistant surface treatment agent and the polyimide precursor which yields the highly heat-resistant amorphous polyimide (B) onto at least one side of a self-supporting film obtained from a polyimide precursor solution which yields the polyimide (A) core layer, and wherein the polyimide film as a whole has a tensile modulus (MD) of between 6 GPa and 12 GPa and a linear expansion coefficient of 5×10 −6 to 30×10 −6 cm/cm/° C. (at 50-200° C.).