Process for the preparation of an organopolysiloxane resin

Abstract

Process for the preparation of an organopolysiloxane resin, which comprises in a first stage reacting at least one silane of the formula R.sub.a Si(OR.sup.1).sub.4-a (I) in which a has a value of 0, 1, 2 or 3, R and R.sup.1 are monovalent organic radicals which may be the same or different and/or a partial hydrolyzate thereof, with the proviso that at least one silane of formula (I), where a is 0 or 1 and/or a partial hydrolyzate thereof is employed, and optionally an organo(poly)siloxane with water in the presence of a poly-protic acid and optionally other substances, subsequently partly neutralizing the acid by addition of a base and then distilling off at least some of the compound R.sup.1 OH formed, in a second stage reacting the homogeneous reaction mass resulting from the first stage in the presence of a base and a water-insoluble organic solvent and distilling off the water and the compound R.sup.1 OH, in a third stage, bringing the homogeneous reaction mass resulting from the second stage to a pH of between 6 and 8 by buffering with a poly-protic acid and/or salts thereof, distilling off the water and any compound R.sup.1 OH still present and filtering off the salt which has precipitated, and optionally, in a fourth stage separating the homogeneous reaction mass resulting from the third stage from the water-insoluble organic solvent.

Dependencies are inferred from the claim text.