| 摘要 |
PROBLEM TO BE SOLVED: To provide hollow silica powder with excellent alkali resistance, to provide a method for producing the same, and to provide application thereof. SOLUTION: The hollow silica powder essentially consists of silica (SiO<SB>2</SB>), and in which the average particle diameter is 5 to 120 nm, the thickness of a shell is 1 to 35 nm, and the number of silanol groups (≡Si-OH groups) is 1 to 10 pieces/nm<SP>2</SP>. In the method for producing hollow silica powder, by soap-free polymerization wherein organic polymer particles to form a core essentially consist of a polymerizable monomer, and it is copolymerized with an ionic comonomer at a mole ratio of 150:1 to 2:1, the particles with the average particle diameter of 5 to 90 nm are produced, a cationic water-soluble polymer and a nonionic water-soluble polymer are added thereto, the liquid comprising the core particles is substituted from water for alcohol, thereafter, alkoxysilane, water and a basic substance are added thereto so as to cover the silica, thus powder made of core shell particles which have the average particle diameter of 5 to 120 nm, and in which the thickness of the silica shell is 1 to 35 nm is produced, and thereafter, the core is removed. COPYRIGHT: (C)2011,JPO&INPIT |
