| 摘要 |
<p>A white plastic pigment utilized in paper, paint, fiber and so forth, and particularly one comprising silica particles as the core and having a surface coated with a vinylic resin. It can be produced by dispersing silica particles in water in the presence of sulfate radical ions as the emulsifier and adding a vinylic monomer to the dispersion to conduct emulsion polymerization. A plastic pigment of the invention has a hollow or porous layer present in between the core and the coating resin. It can be produced by dispersing silica particles in water in the presence of sulfate radical ions as the emulsifier, adding a vinyl carboxylate monomer to the dispersion to conduct emulsion polymerization to thereby coat the surfaces of the silica particles, further adding thereto a vinylic monomer to conduct emulsion polymerization, and adding a basic compound thereto to neutralize the carboxylic acid. Alternatively it can be produced by dispersing silica particles in water in the presence of sulfate radical ions as the emulsifier, adding a vinyl carboxylate monomer and a cross-linking monomer to the dispersion to conduct emulsion polymerization to thereby coat the surfaces of the silica particles, adding a basic compound thereto to neutralize the carboxylic acid to thereby form a hollow or porous layer, and further adding thereto a vinylic monomer to conduct emulsion polymerization to thereby coat the surfaces of the particles.</p> |
