Polysiloxanes with (meth) acrylate ester groups linked through sic groups and their use as radiation-curable coating materials for flat carriers

Abstract

Polysiloxanes with (meth)acrylate ester groups linked over SiC groups are disclosed which are obtainable by the reaction of epoxy-functional polysiloxanes of the general formula ##STR1## in which R.sup.1 are the same or different low molecular alkyl groups with 1 to 4 carbon atoms or phenyl groups, R.sup.2 is the same as R.sup.1 or presents the R.sup.3 group 70 to 100% of the R.sup.3 groups being epoxy functional groups and 30 to 0% being alkyl groups with 2 to 20 carbon atoms or hydrogen, with the proviso that the average molecule contains at least 1.5 epoxy groups, a has a value of 1 to 1,000 and b a value of 0 to 10; with such amounts of an acid mixture, comprising (a) 10 to 90 mole percent of (meth)acrylic anhydride and (b) 90 to 10 mole percent of (meth)acrylic acid, that the sum of (a) and (b) adds up to 100 mole percent, and that there are present 0.8 to 1.9n and preferably 1.1 to 1.9n acid equivalents per n epoxide equivalents. The polysiloxanes are useful as radiation-curable adhesive coating materials for flat backings. The siloxanes adhere well to the backing that is to be coated and cured at a high rate, the coating having a good chemical and physical resistance and a high flexibility. The adhesive coating can be matched to the chemical character of the adhesive and adjusted to the desired degree of abhesiveness.

Dependencies are inferred from the claim text.