| 摘要 |
The present invention relates to a method for processing a titanium dioxide pigment and to said pigments and uses thereof. The method comprises the steps of providing an aqueous suspension of titanium dioxide core particles to an elevated temperature, and introducing a silicon containing compound into said slurry the pH of which is made alkaline, and decreasing the pH of said slurry to a value of about 6 for precipitating the silicon containing layer onto said titanium dioxide core, and introducing subsequently an aluminum containing compound into said slurry the pH of which is acidic, and increasing the pH of said slurry to a neutral value. Subsequently, a phosphate containing compound is introduced to said slurry, the resulting slurry is filtered into a suspension cake, and an organosilane compound is introduced to said suspension and the obtained pigment product is dried. Optionally, phosphate containing compound is added after filtration and washing into silica-alumina coated pigment slurry. Improved colour stability is obtained in polycarbonate plastics plated prepared using above mentioned titanium dioxide pigments. |
