The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 21, 1998
Filed:
Jun. 11, 1997
Loic Doguet, Peage de Roussillon, FR;
Patricia Fompeyrine, Ste-Foy-les-Lyon, FR;
Etienne Foucher, New York, NY (US);
Frederic Leising, Avilly St-Leonard, FR;
Rhone-Poulenc Chimie, Courbevoie, FR;
Abstract
The invention relates to a process for the preparation of polyorganosiloxanes by hydrolysis of organohalosilanes of formula (I) R.sub.a R.sup.1.sub.b SiX.sub.c, wherein R and R.sup.1 identical or different, are an hydrogen atom or a linear or branched C.sub.1 -C.sub.6 alkyl, aryl, alkylaryl or aralkyl group; X is a halogen atom; and a+b+c=4 and 0<c<4; said process comprising the steps of carrying out three or more successive hydrolysis steps (1), (2), (3), in which the reaction medium is capable of exerting an increasing hydrolysing force on the organohalosilanes (I), wherein step (1) is a hydrolysis under pressure in the presence of an aqueous solution S.sub.1 of saturated hydrogen halide, at the pressure and temperature of the reaction medium; and, optionally, carrying out one or more coalescence step (4).