Patent ID: 6512086
Filing Date: 2003-01-28
Classification: C08G

Abstract:
A process for the preparation of organosilicon compositions consisting of prepolymer A or a mixture of prepolymers A+B, the content of B being between 0 and 30% by weight of the mixtures, in which said prepolymers have the following structural formula: wherein:R is methyl or ethyl; R1 is absent or is an organic hydrocarbon, aliphatic, cycloaliphatic, aromatic or ether radical containing 1 to 18 carbon atoms; R2 is a divalent organic radical with a molecular weight of between 2,000 and 20,000 Daltons deriving from a polyether glycol, preferably constituted by a polypropylene oxide or a propylene oxide and ethylene oxide copolymer of the statistical and/or block type, in which the polyethylene oxide fraction does not exceed 20% by weight; R3 is a divalent hydrocarbon, aliphatic, cycloaliphatic or aromatic radical containing 4 to 36 carbon atoms; n=0, 1 and 2; said process comprising the following steps, which are carried out in a single reactor: a) synthesis of unsaturated prepolymer A1, or of the mixture of unsaturated prepolymers A1+B1, where the content of B1 is between 0 and 30% by weight of the mixture where R, R1, R2 and R3 are as defined above, andb) conversion of A1 or A1+B1 to A and A+B respectively by silylation with alkoxysilanes generated in situ by reaction between chlorosilanes with structure C and orthoformates with structure D HC(OR)3â€ƒâ€ƒ(D) where n and R are as defined above.