PURPOSE: To prepar an energy ray-curable solventless epoxy resin composition which is rapidly curable and gives a cured product having excellent weather resistance, adhesive property, flexibility, chemical resistance, etc., by compounding an epoxy resin with an ultraviolet absorber and a specific catalyst precuresor.
CONSTITUTION: An energy ray-curable epoxy resin composition comprising (A) 100 parts by weight of an epoxy resin, (B) 0.5-6 parts by weight of a catalyst precursor liberating the catalyst capable of initiating cationic polymerization of an epoxy resin, by energy ray-irradiation, (C) 0.1-10 parts by weight of an ultraviolet absorber, and if necessary, (D) 0.1-8 parts by weight of an antioxidant. The component (B) is pref. the onium salt of a Lewis acid, e.g. an aromatic diazonium salt complex of a halide expressed by the formula (MXn+m is tetrafluoroborate, etc.; Y is nitro, etc.; m is the charge number of the halide complex anion; n is the number of the halogen atom in the Lewis acid), etc.
NAKAZAWA MASAHIKO
UENO TOKIO
