COMPOSITION FOR OPTICAL RESIN, OPTICAL RESIN AND OPTICAL LENS

PROBLEM TO BE SOLVED: To obtain an ultraviolet-curable composition having a high refractive index, balanced among transparency, optical strain, heat resistance, dyeability, etc., and emitting less odor during processing by mixing three specified components with each other. SOLUTION: Fifty (50) to 80wt.% thio(meth)acrylate compound represented by formula I, II or III [wherein R is formula IV (wherein R1 is H or methyl; R2 is H or methyl; R3 is H, methyl or ethyl; X is O or S; i is 1 or 2; j, k, m, n, r, s and t are each 0 or 1) or thio(meth) acrylate compound represented by formula V, VI or VII (wherein R is as defined in formula I), 5-20wt.% at least trifunctional (meth)acrylate compound and 10-30wt.% at least trifunctional polythiol compound being a mercaptoglycolic acid or mercaptopropionic acid ester of a polyol compound are polymerized and cured to obtain a highly- refractive-index optical resin having a refractive index (nD) of 1.58 or above. A composition containing this resin is polymerized by irradiation with ultraviolet rays to obtain an optical lens.