Process for producing a high refractive index material forming composition and its cured product, as well as a high refractive material forming composition

PROBLEM TO BE SOLVED: To provide a siloxane-based composition giving cured products having excellent heat resistance, excellent ultraviolet ray resistance, excellent light transmissivity, and high refractive index, and to provide a method for producing the same. SOLUTION: This highly refractive material-forming composition comprising 100 pts.wt. of the fine particles (A) of at least one metal oxide selected from the group consisting of zirconium oxide, titanium oxide, zinc oxide, tantalum oxide, indium oxide, hafnium oxide, tin oxide, niobium oxide, and their composite products, a siloxane-based condensed product (B) in an amount of 10 to 400 pts.wt. converted into a perfectly hydrolyzed condensation product, and 1 to 100 pts.wt. of a chelating agent (C), is characterized in that the refractive index of a cured product formed by curing the composition with light having wavelength of 633 nm at 25°C is 1.55 to 3.00, and the refractive index of a 10 μm-thick cured film formed by curing the composition with light having wavelengths of 500 to 700 nm is ≥90%. COPYRIGHT: (C)2007,JPO&INPIT