PURPOSE: To obtain a resin composition which is excellent in photosensitivity and developability and can give a cured product excellent in adhesion, soldering- heat resistance, chemical resistance, electrolytic corrosion resistance, plating resistance, etc., by mixing a specified prepolymer with a specified diluent and specified compounds.
CONSTITUTION: This resin composition comprises a photosensitive prepolymer having at least two ethylenic unsaturations in the molecule (e.g. an adduct of phthalic anhydride with a product prepared by esterifying a novolac epoxy resin with acrylic acid), a diluent comprising a photopolymerizable vinyl monomer and/or an organic solvent (e.g. propylene glycol dimethyl ether), a compound of formula I (wherein R1 is H or 1-9C alkyl) and a compound of formula II [wherein R2 and R3 are each 1-3C alkyl; R4 is OR5-OCH2CH2OR5 (wherein R5 is 1-13C alkyl), H, 1-13C alkyl, phenyl or a group of formula III].
OKUBO TETSUO
SASAHARA KAZUNORI
