HYDROPHOBIC SPHERICAL SILICA FINE PARTICLES HAVING HIGH FLOWABILITY, ITS METHOD FOR PRODUCING THE SAME, TONER EXTERNAL ADDITIVE FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT USING THE SAME AND ORGANIC RESIN COMPOSITION CONTAINING THE SAME

摘要

PPROBLEM TO BE SOLVED: To provide hydrophobic spherical silica fine particles which can impart flowability, caking resistance and satisfactory electrostatic charges to a toner, which has a small particle diameter, high flowability, high dispersibility and low cohesiveness and thus are useful as a toner external additive. PSOLUTION: The hydrophobic spherical silica fine particles are prepared by a hydrophobic treatment process comprising a step of introducing an RSP1/SPSiOSB3/2/SBunit (wherein, RSP1/SPis a substituted or non-substituted monovalent hydrocarbon group of 1-20C) on the surface of a hydrophilic spherical silica fine particle practically consisting of an SiOSB2/SBunit obtained by hydrolyzing and condensing a tetrafunctional silane compound and/or its partial hydrolysis-condensation product and then a step of introducing an RSP2/SPSB3/SBSiOSB1/2/SBunit (wherein, RSP2/SPmay be the same or different and is a substituted or non-substituted 1-20C monovalent hydrocarbon group). The hydrophobic spherical silica fine particles have a basic flowability energy of 500 mJ or less and a particle diameter of 0.005-0.09 μm. PCOPYRIGHT: (C)2009,JPO&INPIT