Post-treated titanium dioxide and process for producing same

Abstract

This invention concerns a new product consisting of TiO.sub.2 particles having pigmentary granulometric and morphological characteristics. It includes a chemically reactive coating consisting of a mixture of oxides and oxychlorides selected from the group consisting of Al.sub.2 O.sub.3 and AlOCl; SiO.sub.2 and SiOCl.sub.2 ; and ZrO.sub.2 and ZrOCl.sub.2. The particles of reactive TiO.sub.2 product are prepared as follows: the surface of the TiO.sub.2 particles is activated by thermally treating the particles in a moving bed with an anhydrous gas at 400.degree.-600.degree. C. The particles are then made to react in a moving bed at 350.degree. C. to 600.degree. C., in the presence of a carrier gas, with an inorganic chloride selected from the group consisting of AlCl.sub.3, SiCl.sub.4 and ZrCl.sub.4. This new product is useful, for instance, in TiO.sub.2 pigments coated with organic molecules which provide an affinity for the vehicles of paints.

Dependencies are inferred from the claim text.