Titanium dioxide pigments and their preparation.

摘要

This invention relates to improved pigments and their preparation and particularly to titanium dioxide pigments, for use, for instance, in paints.
<??>The titanium dioxide pigment of the present invention comprises a particulate core pigmentary rutile titanium dioxide having a coating of dense amorphous silica and optionally an outer coating containing a hydrous oxide of aluminium characterised in that the particulate core has an inner coating of an oxide or hydrous oxide of zirconium in an amount of up 5 % by weight expressed as ZrO2 on the weight of TiO2 and that the coating of dense amorphous silica carried out on the inner coating is present in an amount of up to 12 % by weight expressed as SiO2 on the weight of TiO2.