| 摘要 |
<p>PURPOSE:To provide the titled compsn. which has dull tint and excellent hiding powder, storage stability and resistance to light, water and chemicals, by coating a specified pigment powder mixture with a carboxyl group-contg. copolymer and dispersing it in an aq. alkaline soln. CONSTITUTION:A pigment powder mixture (A) having a particle size of 10mu or below, composed of 100pts.wt. titanium oxide pigment, 5-100pts.wt. aluminum silicate pigment and optionally not more than 100pts.wt. org. pigment such as azo lake is mixed with an aq. alkaline soln. (B) contg. a carboxyl group-contg. copolymer having an acid value of 30-500 [e.g. a methyl (meth)acrylate/maleic anhydride copolymer] in a quantity of 1/20 to double by weight that of component A. The resulting pigment dispersion is diluted with water and neutralized with an acid to precipitate a copolymer-coated composite pigment compsn. The compsn. is recovered by filtration, washed with water and pressed. The resulting press cake is dispersed in an aq. alkaline soln. to obtain the titled compsn.</p> |
