METHOD FOR PRODUCING HOLLOW PARTICLE, AND OPTICAL MATERIAL AND HEAT INSULATION MATERIAL USING HOLLOW PARTICLE

PROBLEM TO BE SOLVED: To provide a method for producing hollow particles for obtaining silica-based hollow particles with a high porosity and a high strength, and to provide an optical material and a heat insulation material using the hollow particles.SOLUTION: The method for producing the hollow particles comprises: producing the hollow particles with a silica-based material by adding a silica-based material into a solution with core particles, and removing the core particles after drying. The method for producing the hollow particles is characterized by incorporating a crosslinking agent for crosslinking the silica-based material and an acid after the silica type material is added and before the core particles is removed.