METHOD OF PREPARING PEARL PIGMENT Russian patent published in 2003 - IPC

FIELD: varnish-and-paint industry. SUBSTANCE: 20-40 g of ground mica, e.g. phlogopite or vermiculite, are treated for 1-1.5 h with 25% aqueous ammonia solution at 70-90 C. Resulting mica suspension is added at continuous stirring to 1.0 l of 0.2 M water-organic solution of titanium tetrachloride with 20% ethanol concentration, whereupon 5 M NaOH solution is added to pH 8. Appearing precipitate is kept for 1 h in mother solution, filtered off, washed to completely remove chloride ions, and dried at 70-90 C. Product contains 25-40% mica (on conversion to air-dry material), average particle size is 0.30-0.35 mcm, specific surface 140-155 sq.m/g, whiteness 78-82%, brightness 45-47%, spreading capacity 40-50 g/sq.m. EFFECT: improved quality of product. 1 tbl, 5 ex