| 摘要 |
<p>A paint comprises an alkyd resin and a titanium dioxide-calcium sulphate pigment prepared by mixing an aqueous slurry of anhydrite in which the average particle size of the anhydrite is 0.3m to 0.7m in diameter with an aqueous titanium salt (e.g. sulphate) solution, hydrolyzing to form a coprecipitated hydrate, adding to said hydrate a titanium sol and zinc or a zinc compound, and calcining. Calcium carbonate and antimony oxide may be added to the coprecipitated hydrate. The zinc compound may be an organo-zinc compound or zinc oxide, hydroxide, sulphate or halide. Specification 848,617 is referred to.ALSO:A process for preparing a titanium dioxidecalcium sulphate composite pigment having improved chalk resistance, comprises preparing an anhydrite aqueous slurry in which the average particle size of the anhydrite is 0.3 m to 0.7 m in diameter, admixing an aqueous titanium salt (e.g. sulphate) solution with said slurry and hydrolysing the titanium salt to form a coprecipitated titanium hydrate, adding to said hydrate a titanium sol and zinc or a zinc compound in amount of at least 1.0%, calculated as titanium dioxide, and 1.0 to 3.0% calculated as zinc oxide, respectively, and calcining e.g. 700 DEG to 1075 DEG C. Calcium carbonate and antimony oxide may be added with the zinc. The titanium sol may comprise articular crystals having a particle size of 50 to 1500 </>rA in diameter. The zinc compound may be the oxide, hydroxide, sulphate or halide or an organo zinc compound. The anhydrite may be prepared by the reaction of lime, limestone or gypsum with sulphuric acid; and the titanium sol by heat treating an aqueous slurry of an alkali metal titanate or an hydrous titanium dioxide with a monobasic acid or, as in the examples, from titanium tetrachloride, sodium hydroxide with or without hydrochloric acid or sodium titanate and hydrochloric acid. The pigment may be mixed with an alkyd resin vehicle. Specification 848,617 is referred to.ALSO:Ceramic panels are coated with a paint comprising an alkyd resin and a composite titanium dioxide-calcium sulphate pigment (see Division C4). Specification 848,617 is referred to.</p> |
