| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing spherical silica fine particles having a void in an outer shell to obtain silica fine particles of a low refractivity index, by growing porous composite oxide particles (primary particles) in the presence of an electrolyte salt, then removing the inorganic oxides other than silica in the presence of an electrolyte salt, a paint for forming coating film containing the spherical silica fine particles having a void and a matrix for forming a coating film and excellent in stability and film forming property and a base material with a coating film having a low refractive index and excellent in close adhesiveness with a resin etc., strength, reflection preventive capacity etc. by forming a coating film containing the silica fine particles having a void, on the surface of the base material. SOLUTION: The silica fine particles having a void in the outer shell have an average particle diameter in the range of 5-500 nm, a refractive index in the range of 1.15-1.38, molar ratio, MO<SB>X</SB>/SiO<SB>2</SB>, of 0.0001-0.2, wherein silica is represented by SiO<SB>2</SB>and the inorganic oxides other than silica is represented by MO<SB>X</SB>, and the content of alkali metal oxide A<SB>2</SB>O (A: an alkali metal element) is not higher than 5 ppm. In the method of manufacturing, a composite oxide fine particle dispersion solution is prepared by simultaneously adding a silicate and/or a bisilicate and an aqueous solution of an alkali-soluble inorganic compound to an aqueous alkali solution, and then at least a part of elements constituting the composite oxide other than silica is removed by adding an acid. COPYRIGHT: (C)2011,JPO&INPIT
|
