Patent Number: 
Section: claims

1. A composite material comprising:nano-oxide particles obtained by hydrothermal synthesis having an average particle size of 10 nm or less;a dispersant; anda transparent resin material,wherein the dispersant contains a polymer comprising a vinyl monomer in a dispersion solution containing 10 wt. % or less of the vinyl monomer for binding with the nano-oxide particles,wherein the polymer has a degree of polymerization of an integer of 4-10 with the proviso that the integer is a numerical value obtained by dropping a decimal fraction, andwherein the vinyl monomer is represented by the following formula (1):wherein R1 is hydrogen atom or methyl group; R2 is alkyl group, halogen atom, or hydrogen atom; and n is 1. 2. The material according to claim 1, wherein the dispersant and the nano-oxide particles have a weight ratio of 1/99 to 80/20, and the nano-oxide particles and the transparent resin material have a weight ratio of 0.6/99 to 80/20. 3. The material according to claim 1, wherein the nano-oxide particles have an average particle size of 0.5 nm or more and 10 nm or less. 4. The material according to claim 1, wherein the nano-oxide particles are particles of an oxide selected from the group consisting of aluminum oxide, titanium oxide, niobium oxide, tin oxide, indium oxide, zirconium oxide, lanthanum oxide, cadmium oxide, hafnium oxide, erbium oxide, neodymium oxide, cerium oxide, dysprosium oxide, and a mixed oxide of these oxides. 5. A lens comprising:composite material, according to claim 1, which has been molded. 6. The material according to claim 1, wherein the nano-oxide particles have an average particle size of 1-10 nm. 7. A production process of a composite material, comprising:a step of obtaining a dispersant comprising a polymer by polymerizing a vinyl monomer in a dispersion solution containing 10 wt. % or less of the vinyl monomer; anda step of mixing the dispersant, nano-oxide particles obtained by hydrothermal synthesis having an average particle size of 10 nm less, and a transparent resin material,wherein the polymer has a degree of polymerization of an integer of 4-10 with the proviso that the integer is a numerical value obtained by dropping a decimal fraction, andwherein the vinyl monomer is represented by the following formula (1):wherein R1 is hydrogen atom or methyl group; R2 is alkyl group, halogen atom, or hydrogen atom; and n is 1. 8. A production process of a composite material, comprising:a step of obtaining a dispersant comprising a polymer by polymerizing a vinyl monomer in a dispersion solution containing 10 wt. % or less of the vinyl monomer in the presence of polyamine; anda step of mixing the dispersant, nano-oxide particles obtained by hydrothermal synthesis having an average particle size of 10 nm or less, and a transparent resin material,wherein the polymer has a degree of polymerization of an integer of 4-10 with the proviso that the integer is a numerical value obtained by dropping a decimal fraction, andwherein the vinyl monomer is represented by the following formula (1):wherein R1 is hydrogen atom or methyl group; R2 is alkyl group, halogen atom, or hydrogen atom; and n is 1. 9. A production process of a dispersant, for nano-oxide particles obtained by hydrothermal synthesis having an average particle size of 10 nm or less, the dispersant containing a polymer comprising a vinyl monomer; the production process comprising:a step of polymerizing the vinyl monomer in a dispersion solution containing 10 wt. % or less of the vinyl monomer,wherein the polymer has a degree of polymerization of an integer of 4-10 with the proviso that the integer is a numerical value obtained by dropping a decimal fraction, and represented by the following formula (1):wherein R1 is hydrogen atom or methyl group; R2 is alkyl group, halogen atom, or hydrogen atom; and n is 1. 10. A production process of a dispersant, for nano-oxide particles obtained by hydrothermal synthesis having an average particle size of 10 nm or less, the dispersant containing a polymer comprising a vinyl monomer; the production process comprising:a step of polymerizing the vinyl monomer in a dispersion solution containing 10 wt. % or less of the vinyl monomer in the presence of polyamine,wherein the polymer has a degree of polymerization of an integer of 4-10 with the proviso that the integer is a numerical value obtained by dropping a decimal fraction, andwherein the vinyl monomer is represented by the following formula (1):wherein R1 is hydrogen atom or methyl group; R2 is alkyl group, halogen atom, or hydrogen atom; and n is 1.