Patent ID: 7026427

Claim:
A process for the preparation of an organopolysiloxane resin, comprising, in the order stated: reacting in a 1st stage, at least one silane of the formula R 3 SiOR 1 (I) and/or its hydrolyzate R 3 SiOSiR 3 , where R are identical or different, and are a monovalent organic radicals, and R 1 is an alkyl radical, and at least one silane of the formula Si(OR 2 ) 4 (II) and/or its partial hydrolyzates, where R 2 are identical or different and are alkyl radicals, and optionally an organosilicon compound selected from the group consisting of silanes of the formula R 3 a Si(OR 4 ) 4-a (III) and/or their partial hydrolyzates, where a is 1 or 2, R 3 are identical or different and are monovalent organic radicals, and R 4 are identical or different and are alkyl radicals, and organopolysiloxanes of the formula (R 5 2 SiO) b (IV), where R 5 are identical or different and are monovalent organic radicals, and b is an integer with a value of 3 to 8, and mixtures thereof, with water in the presence of acid, at least part of the alcohol formed being distilled off; in a 2nd stage, reacting a homogeneous reaction mixture obtained in the 1st stage in the presence of base and in the presence of a water-insoluble organic solvent in at least a sufficient amount to obtain a homogeneous reaction mixture, and removing water and alcohol and optionally part of the water-insoluble organic solvent by distillation; in a 3rd stage, neutralizing the reaction mixture obtained in the 2nd stage with acid, and distilling away any water still present, alcohol and part of the water-insoluble organic solvent; in a 4th stage, treating the reaction mixture obtained in the 3rd stage with at least one organopolysiloxane and removing precipitated salt formed in the neutralization; optionally, in a 5th stage, separating the homogeneous reaction mixture obtained in the 4th stage from water-insoluble organic solvent.