Patent ID: 6923974
Filing Date: 2005-08-02
Classification: A61K,A61Q,C01P,C09C

Abstract:
1. A method of producing a flaky fine powder, comprising: adding alkoxysilane and/or silicic acid solution to a dispersion containing a flaky or scaly base and spherical silica particles, and immobilizing said spherical silica particles on the surface of said flaky or scaly base by hydrolyzing said alkoxysilane and/or gelling said silicic acid solution, said flaky or scaly base having a thickness of about 1 μm or less and is selected from the group consisting of mica, talc and platelet shaped silica, and said spherical silica particles comprise SiO wherein the permittivity (∈) of said dispersion is in the following range: and the ion concentration (N) of the sun of cations and anions in said dispersion satisfies the following conditions: (a) 200 ppm≦N≦5*10 4 ppm, when ∈ is 15, (b) 3*10 4 ppm≦N≦2*10 5 ppm, when ∈ is 80, and (c) N is in a quadrilateral area formed by A (15, 200), B (15, 5*10 4 ), C (80, 2*10 5 ) and D (80, 3*10 4 ) in the (X, Y) coordinate system with the X axis for the permittivity (∈) (−) and the Y axis for the ion concentration (N) (ppm), when 15≦∈≦80.