摘要 |
<p>Pigmented silica microspheres having an average diameter from 2 mu m to 100 mu m and consisting essentially of from 10% to 70% by weight of particulate pigment, dispersed throughout a microporous silica matrix and, optionally, containing a coating of dense amorphous silica. The microspheres are produced by acidifying a water-in-oil emulsion. The pigmented silica micropheres are particularly useful as opacifying agents for coating compositions and as fillers for paper.</p> |