| 摘要 |
The invention provides a coated particulate inorganic material comprising: (i) a particulate inorganic material selected from titanium dioxide, doped titanium dioxide and combinations thereof, wherein the particulate inorganic material has an average crystal size of from 0.4 μm to 2μm; and (ii) a coating on said particulate inorganic material, the coating comprising a first layer and a second layer. The material for the first layer is one or more material selected from inorganic oxides and inorganic phosphates, with the inorganic oxide being independently selected from an oxide of: (a) group 4 (IVB) and 12 (IIB) transition metals selected from Ti, Zr and Zn; and (b) group 13 to 15 (IIIA-VA) p-block elements selected from Si, P and Sn; and (c) lanthanides. The inorganic phosphate is independently selected from a phosphate of: (i) group 1 (IA) and 2 (IIA) alkali and alkaline earth metals selected from H, Li, Na, K, Rb, Be, Mg, Ca and Sr; and (ii) group 3 (IIIA) and 4 (IVB) transition metals selected from Sc, Y, Ti and Zr; and (iii) group 13 to 15 (IIIA-VA) p-block elements selected from Al, Ga, In, TI, Ge, Sn and Pb. The material for the second layer is alumina. The amount of the first layer on the particulate inorganic material is from 0.1 to 2.2% w/w, when considering the total weight of the first layer material with respect to the total weight of the particulate inorganic material. The amount of the second layer on the particulate inorganic material is 0.1 to 3.5% w/w when considering the total weight of the second layer material with respect to the total weight of the particulate inorganic material. The total amount of coating is from 0.2 to 4.5% w/w when considering the total weight of the first and second layer material with respect to the total weight of the particulate inorganic material. |
