PROCESS FOR PRODUCING DISPERSION OF HOLLOW FINE SiO2 PARTICLES, COATING COMPOSITION, AND SUBSTRATE WITH ANTIREFLECTION COATING FILM

摘要

To provide a process for producing a dispersion of hollow fine SiO₂ particles which contains no residual core fine particles, generates no uncontrollable agglomerates, and is easy to filtrate.;A process for producing a dispersion of hollow fine SiO₂ particles having hollow fine SiO₂ particles dispersed in a dispersion medium, which comprises at least the following steps (a), (b) and (c):(a) a step of reacting a precursor of SiO₂ at a pH higher than 8 in the presence of fine ZnO particles constituting the core in the dispersion medium to form SiO₂, thereby to obtain a dispersion of fine particles comprising the fine ZnO particles covered with the formed SiO₂;(b) a step of mixing an acidic cation exchange resin with the dispersion of fine particles obtained in the above step (a) to bring them into contact with each other, to dissolve the fine ZnO particles as the core at a pH within a range of from 2 to 8; and(c) a step of separating the acidic cation exchange resin by solid-liquid separation after the fine ZnO particles are completely dissolved, to obtain the dispersion of hollow fine SiO₂ particles.