Aluminiumoxidbeschichtete Titandioxidpartikel und Verfahren zu deren Herstellung unter Verwendung von verdichtenden Agentien

摘要

The invention is directed to a method for reducing the chemical activity and photo activity of titanium dioxide nanoparticles comprising adding a densifying agent, such as citric acid, to an aqueous slurry of the titanium dioxide nanoparticles; treating the aqueous slurry with a source of alumina, such as a solution of sodium aluminate, to form alumina- treated titanium dioxide nanoparticles. In one embodiment the particles are treated with a source of silica, such as a solution of sodium silicate. The nanoparticles of this invention can also be treated with a source of silica and a source of alumina. The treated nanoparticles can be silanized. The titanium dioxide nanoparticles described herein are useful in cosmetic, coating and thermoplastic compositions.