| 摘要 |
PURPOSE:To readily produce microspherical silica in a well dispersed state, by dissolving aqueous ammonia in an organic solvent, adding a tetraalkoxysilane and cooling the resultant hydrolyzed tetraalkoxysilane. CONSTITUTION:Aqueous ammonia is dissolved in an organic solvent and a tetraalkoxysilane or partial condensate thereof is added and hydrolyzed. The resultant hydrolyzate is then cooled below the melting point of the solvent or water to separate silica microspheres. An organic solvent capable of dissolving water is used as the above-mentioned organic solvent. The tetraalkoxysilane or partial condensate thereof is readily produced from silicon tetrachloride and an alcohol and particularly tetraethoxysilane (ethyl silicate) or partial condensate thereof is readily available as a commercial product.
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