Acrylate and/or methacrylate-substituted organopolysiloxanes

Claim 1

A process for the preparation of an organopolysiloxane comprising acrylate and/or methacrylate functional groups, which comprises at least partially transesterifying, in the presence of a catalytically effective amount of a tin-containing compound (A) having a valency of 4 selected from the group consisting of inorganic compounds of tin and organic compounds of tin selected from dialkyltin oxide, tin carboxylate, dialkytin dicarboxylate, tin chelate or the reaction product of a dialkyltin oxide with an organic ester or alkyl silicate, an organopolysiloxane (B) containing at least two siloxy, u nits per molecule, at least one of such units corresponding to the formula: ##STR11## in which a is 1 or 2, the symbols R, which may be identical or different, are each a C 1 -C 12 alkyl radical, a phenyl radical or a 3,3,3-trifluoropropyl radical, at least 80 mole % of radicals R being methyl radicals, and the symbols Y, which may be identical or different, are each a C 1 -C 18 straight or branched chain alkylene linkage, with an ester (C) of the formula: ##STR12## in which X is a hydrogen atom or a methyl radical and Z is a C 1 -C 6 alkyl radical.