| 摘要 |
Pigmented vesiculated silica microspheres having an average diameter from 0.5 .mu. to 50 .mu., a maximum vesicle diameter less than 50 .mu. and a volume of vesicles from 5% to 95% of the total volume of the microspheres, produced by acidifying an oil-in-water-in-oil emulsion prepared by a double emulsion technique. The vesiculated silica microspheres, containing clay, calcium carbonate, white lead, zinc oxide, zinc sulfide or titanium dioxide pigment, are particularly useful as opacifying agents for coating compositions and as fillers for paper. |
