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:
Dec. 25, 1990
Filed:
Sep. 26, 1989
Shosaku Sasaki, Ichihara, JP;
Hiroshi Masaoka, Saitama, JP;
Toray Silicone Company Limited, Tokyo, JP;
Abstract
The method of the present invention provides for the manufacturing of an alkenyl group-containing organopolysiloxane using an alkali catalyst in the presence of oxygen and in the absence of carbon dioxide. The copolymer is characterized by a viscosity of at least 500 cst at 25.degree. C., can be efficiently manufactured and is free of gelation. In the method an organopolysiloxane represented by the average formula R.sup.1.sub.a SiO.sub.(4-a)/2 in which R.sup.1 is a monovalent hydrocarbon group free of aliphatic unsaturation and a 4-8 carbon atom alkenyl group-containing organopolysiloxane represented by the average formula R.sup.2.sub.b R.sup.3.sub.c SiO.sub.(4-b-c)/2 are copolymerized.