| abstract |
R 1 SiO 3 is formed on the surface of hydrophilic spherical silica fine particles substantially composed of SiO 2 units obtained by hydrolysis and condensation of a tetrafunctional silane compound and / or a partial hydrolysis condensation product thereof. / 2 units (wherein R 1 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms) and R 2 3 SiO 1/2 units (wherein R 2 is the same or different, A non-substituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms). It is composed of hydrophobic spherical silica fine particles having an average particle diameter in the range of 0.005 to 1.0 μm, a particle size distribution D 90 / D 10 of 3 or less, and an average circularity of 0.8 to 1. A fluidizing agent for powders. [Effect] The fluidizing agent comprising the hydrophobic silica fine particles obtained by the present invention can give high fluidity which has not been obtained conventionally by adding it to various powders. [Selection figure] None |