Abstract: Novel siloxane copolymers are described having an average of at least two alkenyloxy groups of the formula--OCR.sup.2 .dbd.CH.sup.2 CH.sub.3,in which R.sup.2 represents hydrogen or a methyl radical.These siloxane copolymers are prepared by reacting in a first stage, an organic compound (1) containing more than two aliphatic double bonds of the formula OCHR.sup.2 CR.sup.2 =CH.sub.2 where R.sup.2 is the same as above, with an organopolysiloxane (2) having at least one Si-bonded hydrogen atom per molecule in the presence of a catalyst (3) which promotes addition of the Si-bonded hydrogen to an aliphatic double bond and in a second stage heating the siloxane copolymer in the presence of a catalyst (4) which promotes shifting of the terminal double bond to form copolymers having an internal double bond.

Abstract: Novel, alkenyloxy-functional organosilicon compounds are described which contain at least one Si-bonded Y radical per molecule having the formula--(CH.sub.2).sub.2 --R.sup.2 --(A--R.sup.3).sub.z --O--CH.dbd.CH--CH.sub.2 --R.sup.4 (I),in whichA represents --O--, --S-- or ##STR1## R.sup.2 represents a linear or branched alkylene radical having from 1 to 7 carbon atom(s) per radical or a cycloalkylene radical having from 5 to 7 carbon atoms per radical, R.sup.3 represents a linear or branched alkylene radical having from 2 to 4 carbon atoms per radical, which may be substituted by a hydroxyl group, methoxy group, ethoxy group or trimethylsiloxy group, R.sup.4 represents a hydrogen atom or an alkyl radical having from 1 to 4 carbon atoms(s) per radical, and z is 0, 1 or 2.The alkenyloxy-functional organosilicon compounds are preferably silanes or organopolysiloxanes.The alkenyloxy-functional organopolysiloxanes can be crosslinked, for example, with ultraviolet light.

Abstract: Novel, alkenyloxy-functional organosilicon compounds are described which contain at least one Si-bonded Y radical per molecule having the formula--(CH.sub.2).sub.2 --R.sup.2 --(A--R.sup.3).sub.z --O--CH.dbd.CH--CH.sub.2 --R.sup.4 (I),in which A represents --O--, --S-- or ##STR1## R.sup.2 represents a linear or branched alkylene radical having from 1 to 7 carbon atom(s) per radical or a cycloalkylene radical having from 5 to 7 carbon atoms per radical, R.sup.3 represents a linear or branched alkylene radical having from 2 to 4 carbon atoms per radical, which may be substituted by a hydroxyl group, methoxy group, ethoxy group or trimethylsiloxy group, R.sup.4 represents a hydrogen atom or an alkyl radical having from 1 to 4 carbon atoms(s) per radical, and z is 0, 1, or 2. The alkenyloxy-functional organosilicon compounds are preferably silanes or organopolysiloxanes. The alkenyloxy-functional organopolysiloxanes can be crosslinked, for example, with ultraviolet light.