Process for coating metal oxide pigments and pigments obtained.

摘要

A new process for the production of pigments suitable for use in paper laminates has been developed in which a metal oxide is treated with a water-soluble salt of zinc or a phosphate or phosphoric acid and subsequently with an alkali metal aluminate in such a manner that there is deposited on the metal oxide a coating containing zinc and phosphate ions together with aluminium ions. The pH of the dispersion following the metal oxide is maintained at a value not exceeding 8.0 during precipitation. A particularly useful pigment is produced which has a coating containing zinc ions in an amount of 0.5 to 5% by weight as ZnO, phosphate ions in an amount of 0.2 to 3% as P2O5 and aluminium ions in an amount of 0.5 to 5% expressed as Al2O3 on the weight of TiO2.