| 摘要 |
Improved coated inorganic pigments having a first coating of Al2O3, SiO2, or optionally other oxide such as a source of P2O5, or mixtures thereof, an optional coating of ZrO2, SnO2, TiO2, SiO2, CeO2 or mixtures thereof, and a final coating of Al2O3 which exhibit good durability, dispersibility, and optical properties in plastic or paint compositions are disclosed. Also disclosed is a process whereby an aqueous slurry of an inorganic pigment is milled to achieve a particular particle size distribution, a first coating of Al2O3, SiO2, or optionally other oxide such as a source of P2O5, or mixtures thereof is precipitated onto the pigment material within a first pH range, an optional amount of ZrO2, SnO2, SiO2, TiO2, CeO2 or mixtures thereof is added to the aqueous slurry within a second pH range to obtain an optional coating over the first coating, and a final coating of Al2O3 is added over the prior coating(s). |
