| 摘要 |
PROBLEM TO BE SOLVED: To obtain a silica useful as a reinforcing filler for a silicone rubber composition by bringing an organic silicon compound selected from organosilane, organosiloxane and organodisilazane into contact with a hydrophilic precipitated silica in the presence of a mixture of water and a miscible organic solvent of an amount sufficient for promoting the reaction of the organic silicon compound with the hydrophilic precipitated silica. SOLUTION: An aqueous suspension of a hydrophilic precipitated silica is brought into contact with one or more kinds of organic silicon compound selected from an organosilane of formula I: R1aHbSiX4-a-b, an organosiloxane expressed by the average unit formula II: R2nSiO(4-n)/2 and an organodisilazane expressed by formula III: (R33Si)2NH in the presence of a catalytic amount of an acid. A mineral acid such as hydrochloric acid, hydroiodic acid and sulfuric acid can be used as the acid catalyst. In the above formulas, R1 groups are each a 1-12C hydrocarbon group; R2 groups are each H, Cl or the like; R3 is a 1-12C hydrocarbon group; X groups are each a hydrolyzable group bonded to Si; (a) is 2 or 3; (b) is 0 or 1; a+b is 1-3; (n) is an integer of 2-3. |
