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:
Apr. 27, 1993
Filed:
Jan. 25, 1991
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
Proposal is given of a method for the preparation of an organopolysiloxane highly freed from any trace amount of the residue of sulfuric acid or fuming sulfuric acid by the siloxane rearrangement reaction of organosiloxane oligomers into equilibirium by using the acid catalyst. The inventive method comprises subjecting the reaction mixture, after completion of the reaction but before the conventional step of washing with a large volume of water to remove the acid residue, to a hydrolysis reaction of the acid residue bonded to the organopolysiloxane molecules with admixture of a limited amount of water and separating the mixture into aqueous and organopolysiloxane phases to discard the acid-containing aqueous phase.