Process for the manufacture of organopolysiloxanes for use in abhesive coating materials

In a method for the manufacture of organopolysiloxanes suitable for use as active ingredients in abhesive coating materials for two-dimensional carriers wherein an organopolysiloxane having SiCl groups is reacted with pentaerythritol triacrylate or pentaerythritol trimethacrylate, whereby:

• (a) said organopolysiloxane having the formula ##STR11## in which R.sup.1 is selected from the group consisting of alkyl with 1 to 4 carbon atoms, a vinyl group, a phenyl group, and combinations thereof, with the proviso that at least 90 mole percent of the R.sup.1 groups are methyl groups,
• a has a value of 1.8 to 2.2, and
• b a value of 0.004 to 0.5;
• (b) the reaction being carried out with at least equimolar amounts of pentaerythritol triacrylate or pentaerythritol trimethacrylate based on the amount of the polysiloxane;
• and
• (c) the product from the process being separated from the solid components suspended therein, the improvement which comprises:
• the organochlorosiloxane is initially reacted with at least 2 molar amounts per SiCl group of a dialkylamine whose alkyl groups in each case have 3 to 5 carbon atoms and in which each of the carbon atoms adjacent to the nitrogen carry at most one hydrogen atom and wherein the product of this initial reaction is reacted with pentaerythritol triacrylate or pentaerythritol trimethacrylate.