Resin composition and the protective film

PROBLEM TO BE SOLVED: To provide a composition suitable for forming a cured film of high flatness and a protective film for a photo device having high surface hardness and excellent in various resistances such as heat and pressure resistances, acid resistance, alkali resistance, and sputtering resistance, and a protective film formed therewith. SOLUTION: This composition contains a copolymer [A] of an unsaturated compound (a1) containing an epoxy group and an olefinic unsaturated compound (a2) other than (a1), a reaction product [B] of an epoxy resin (b1) containing a hydroxy group and an alkoxysilane (b2), and a compound [C] capable of cationic polymerization except components [A] and [B], and this protective film is formed therewith. COPYRIGHT: (C)2004,JPO