Method for the production of polymethylvinylsiloxane resins wtih recycling of volatile oligoorganosiloxanes

摘要

The invention relates to the field of silicon resins, particularly polymethylvinylsiloxane resins. The invention more specifically relates to a method for the production of polymethylvinylsiloxane resins comprising at least two different types of siloxy motifs R₃SiO_1/2 (motif M) and SiO_4/2 (motif Q, optionally Q^OH), said method comprising the following steps: a) producing a siloxane resin comprising motifs Q by acidic hydrolysis of a siloxane resin precursor, preferably an alkaline silicate; b) functionalizing the siloxane resin obtained in step a) with halogenosilanes in the presence of an apolar solvent, the functionalizing generating sub-products including volatile oligosiloxanes (silox); c) recovering silox produced in step b) in a solution in the apolar solvent; and d) subjecting the resin functionalized in step b) to rearrangement with the aid of a strong base in order to eliminate the silanols, wherein at least a part of the silox produced during step b) and recovered in step c) is recycled.