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:
Mar. 04, 1997
Filed:
Dec. 28, 1995
Dimitris E Katsoulis, Midland, MI (US);
John R Keryk, Midland, MI (US);
Dow Corning Corporation, Midland, MI (US);
Abstract
The invention relates to a method of forming siloxane polymers using a heteropoly catalyst having a Keggin structure. The method comprises contacting a fluid comprising at least one siloxane polymer precursor selected from the group consisting of cyclic siloxanes (I) having the formula (RR'SiO).sub.a and linear siloxanes (II) having the formula ##STR1## where R is a substituted or unsubstituted monovalent hydrocarbon having from 1 to 6 carbon atoms, R' is hydrogen or a substituted or unsubstituted monovalent hydrocarbon having from 1 to 6 carbon atoms, a is at least 3 and b is at least 1; with an effective amount of a heteropoly catalyst having a Keggin structure, selected from the group consisting of heteropoly acids (III) having the formula H.sub.n XM.sub.12 O.sub.40, salts thereof and mixed acid-salts thereof, where X is B.sup.+3, Si.sup.+4, Ge .sup.+4, p.sup.+5, M is Mo.sup.+6 and n is 3, 4 or 5, as required for the valence of the heteropoly acid to equal 0, at a temperature ranging from about 23.degree. C. to the boiling point of the siloxane polymer precursor.