METHOD OF PREPARING PIGMENT COMPOSITE, AND PIGMENT COMPOSITE Russian patent published in 1999 - IPC

FIELD: chemical industry, more particularly manufacture of colorants for paints, inks and paper. SUBSTANCE: pigment composite comprises titanium dioxide substrate, and zirconium and aluminium oxide layers, TiO₂ particles are dispersed in water and sodium hexamethaphosphate dispersant is added. The resulting titanium dioxide suspension is heated to 46.11-50 C. H₂SO₄ solution is added to adjust pH from 7 to 9. Zirconium sulfate solution is added, 0.1-2.5% of zirconium hydroxide is precipitated from TiO₂ in terms of ZrO₂. Aqueous NaOH solution is added to adjust pH from 7 to 9. Aqueous solution of sodium aluminate is added. 3.5-4% of aluminium hydroxide is precipitated from TiO₂ in terms of Al₂O₃. The resulting product is filtered, washed with water and dried at 110 C, and ground. EFFECT: improved optical properties such as scattering, luster, brightness and color and also resistance of the pigment composite. 8 cl, 1 ex, 1 tbl