| 摘要 |
The invention provides alkenyl-containing siloxane copolymers preparable by reacting:a compound (1) having at least three aliphatic double bonds, of the general formula whereR2 is a trivalent or tetravalent hydrocarbon of silane radical, andR3 is a hydrogen atom or an alkyl radical, with an organosiloxane having terminal Si-bonded hydrogen atoms, in the presence of a hydrosilylation catalyst,in a second step reacting:the resulting hydrocarbon-siloxane copolymers containing Si-bonded hydrogen atoms with alpha,omega-dialkenylsiloxane polymer in the presence of a hydrosilylation catalyst,and, if desired, in a third step, equilibrating:the resulting alkenyl-containing siloxane copolymers with an organopolysiloxane from the group consisting of linear organopolysiloxanes containing terminal triorganosiloxy groups, linear organopolysiloxanes containing terminal hydroxyl groups, branched organopolysiloxanes with or without hydroxyl groups, cyclic organopolysiloxanes, and copolymers of dioganosiloxane units and monoorganosiloxanes units.
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