Process for the preparation of organopolysiloxane-polyether copolymers with SiOC bonds

A process of preparing organopolysiloxanepolyether copolymers of the kind wherein the polysiloxane blocks are linked to the polyetherblocks through SiOC-linkages, which comprises:

• 1. equilibrating mixtures of organohalogensilanes and organopolysiloxanes or mixtures of organopolysiloxanes with terminal silylhalide groups in the presence of an equilibration catalyst, the molecular weight distribution or the distribution of the individual siloxane structures of the mixtures to be equilibrated deviating from the statistical equilibrium and said equilibration catalyst being a mixed catalyst comprising
• a. hydrogen halide acid and
• b. peralkylated acid amide,
• the amount of said mixed catalyst being in the range of 0.002 to 0.2 mole per siloxane bond to obtain at least approximately equilibrated mixtures of halogen siloxanes,
• 2. separating the mixed catalyst from the halogen siloxanes by phase separation, and
• 3. reacting the halogen siloxanes thus obtained with hydroxyl group containing polyether compounds.