To obtain an organic solvent solution useful to obtain a curable composition having excellent curability and developing excellent hardness when cured by radically copolymerizing polymerizable-unsaturation-containing inorganic oxide colloidal particles dispersed in an organic solvent with a polymerizable- unsaturation-containing epoxy compound in the presence of an onium compound.
This solution is prepared by radically copolymerizing polymerizable-unsaturation-containing inorganic oxide colloidal particles (e.g. particles obtained by reacting colloidal silica with γ- methacryloxypropylmethoxysilane) dispersed in an organic solvent (e.g. xylene/n- butanol mixed solvent) with a polymerizable-unsaturation-containing epoxy compound (e.g. 3,4-epoxycyclohexylmethyl acrylate) in the presence of an onium compound being substantially inert to epoxy groups and desirably represented by formula I or II. In the formulae, Y is N or P; Ra to Rd are each H or a 12C or lower organic group; and X- is an anion, desirably, a halide ion.
AIDA AKIHIKO
WADA SEIJI
