| abstract |
PURPOSE:To provide powder surface such as of organic or inorganic pigment with uniform hydrophobicity with no need of calcination and no development of discoloration, by bringing powder with active points present on the surface into contact with gasified product from cyclic organosiloxane of specific structure to perform polymerization of said siloxane on the surface. CONSTITUTION:Within a closed chamber hold at constant temperature <=100 deg.C (e.g., sterilizer using gas, desiccator), (A) powder heaving on its surface, active points such as acid- or base ones (e.g., yellow iron oxide) and (B) a cyclic organosiloxane of formula I or II (n is 3-6) (e.g., tetramethyl tetrahydrogencyclotetrasiloxane) are each put in a vessel to be left to stand to bring said surface into contact with gasified product, in a molecular state, from said organosiloxane normally for 4-24hr, thus polymerizing said organosiloxane on the surface. |