Abstract: Silylated silica is prepared by silylating silica with an organosiloxane composed of A units of the formula (I) (R13SiO1/2)??(I) and B units of the formulae (IIa-c) (R12SiO2/2), and/or??(IIa) (R1SiO3/2), and/or??(IIb) (SiO4/2)??(IIc), optionally having 1 or 2 attached groups —X on Si atoms, where X is OR, R being hydrogen or a monovalent alkyl radical having 1-4 carbon atoms, halogen, or acetoxy, R1 is a saturated or unsaturated, monovalent, optionally halogenated C1-18 hydrocarbon radical the groups ?SiX or ?SiX2 optionally present in a number C, wherein A, B, and C satisfy the relationships: 1?B?100 or 750<B<10 000, B?A+C, and, when A+C=0, 10?B?100 or 750<B<10 000. The silylated silica has a particularly homogenous coating of silylating agent.
Type:
Grant
Filed:
October 1, 2002
Date of Patent:
May 3, 2005
Assignee:
Wacker-Chemic GmbH
Inventors:
Herbert Barthel, Mario Heinemann, August Altenbuchner