Photosensitive resin composition for optical waveguide and photocurable film for forming optical waveguide core layer, and optical waveguide and opto-electric transmission hybrid flexible printed wiring board using same

A photosensitive resin composition for an optical waveguide, consisting of:

• a resin component;
• a photoacid generator;
• and
• an optional component,
• wherein the resin component comprises an epoxy resin component containing an aromatic epoxy resin and an aliphatic epoxy resin,
• wherein the aromatic epoxy resin shows a solid state,
• wherein the aliphatic epoxy resin contains an aliphatic epoxy resin showing a solid state,
• wherein a content of the aromatic epoxy resin is 55 wt. % or more and less than 80 wt. % of an entirety of the epoxy resin component, and
• wherein a content of the aliphatic epoxy resin is more than 20 wt. % and 45 wt. % or less of the entirety of the epoxy resin component, and
• wherein the optional component is at least one compound selected from the group consisting of:
• (i) an organic solvent selected from the group consisting of ethyl lactate, methyl ethyl ketone, cyclohexanone, 2-butanone, N,N-dimethylacetamide, diglyme, diethylene glycol methyl ethyl ether, propylene glycol methyl acetate, propylene glycol monomethyl ether, tetramethylfuran, dimethoxyethane, and a combination thereof,
• (ii) a coupling agent selected from the group consisting of a silane-based coupling agent, a titanium-based coupling agent, and a combination thereof,
• (iii) an adhesiveness-imparting agent selected from the group consisting of a cycloolefin-based oligomer, a cycloolefin-based polymer, synthetic rubber, and a combination thereof,
• (iv) an antioxidant selected from the group consisting of a hindered phenol-based antioxidant, a phosphorus-based antioxidant, and a combination thereof,
• (v) a leveling agent, and
• (vi) an antifoaming agent.