Patent ID: 8722765

Claim:
A method of manufacturing a resin composition, the method comprising: manufacturing an alumina particle composite; dispersing the alumina particle composite into a first solvent to produce an alumina particle-dispersion liquid; mixing a monomer as a raw material of resin and the alumina particle-dispersion liquid; and polymerizing the monomer in a state where the monomer and the alumina particle-dispersion liquid are mixed together, wherein the step of manufacturing the alumina particle composite comprises: adding an alkali aqueous solution in an aqueous solution with an aluminum salt to produce a reaction mixture containing a gel material of aluminum hydroxide; first heating the reaction mixture at a first temperature not lower than room temperature; after the first heating, second heating the reaction mixture at a second temperature higher than the first temperature; after the second heating, third heating the reaction mixture at a third temperature lower than the second temperature; and after the third heating, fourth heating the reaction mixture at a fourth temperature not less than the room temperature; and dispersing boehmite particles generated in the reaction mixture into a second solvent, and adding an organic acid to the second solvent.