POLYSILOXANES CONTAINING SIC-BOUND (METH-)ACRYLIC ACID ESTER FUNCTIONAL GROUPS AND USES THEREOF AS RADIATION CURABLE COATING MATERIALS FOR FLAT SUBSTRATES

The polysiloxanes are obtainable by reacting epoxy-functional polysiloxanes of the general formula in which R are identical or different lower alkyl radicals having 1 to 4 carbon atoms, or phenyl radicals, R is identical to R or is the radical R , where from 70 to 100 % of the radicals R are epoxy-functional radicals and from 30 to 0 % of the radicals R are alkyl radicals having 2 to 10 carbon atoms or are hydrogen radicals, with the proviso that the average molecule contains at least 1.5 epoxide groups, a has a value of from 1 to 1000, and b has a value of from 0 to 10, with such amounts of an acid mixture comprising from 10 to 90 mol-% of (meth)acrylic anhydride and from 90 to 10 mol-% of (meth)acrylic acid, where the sum must give 100 mol-%, that from 0.8 to 1.9 n acid equivalents are present per n epoxide equivalents, at elevated temperature, if necessary in the presence of solvents and conventional esterification catalysts. These polysiloxanes are used as radiation-curable, abhesive coating compositions for flat substrates. The siloxanes adhere well to the substrate to be coated, cure at a fast rate and give a coating having good chemical and physical resistance at high flexibility. The abhesive coating can be customised to the chemical character of the adhesive and to the desired degree of abhesiveness.