Process for preparing organopolysiloxane resins containing Si-bonded vinyl groups

US4242486A · kind A · utility

Assignee

• Wacker Chemie AG · DE

Inventors

• Peter August · Burghausen, DE
• Willi Primas · Simbach, DE

Key dates

• Filing date: May 14, 1979
• Grant date: Dec 30, 1980
• Expiry date: May 14, 1999

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G77/20
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for preparing organopolysiloxane resins containing Si-bonded vinyl groups which comprises heating to a temperature of from about 85.degree. to 95.degree. C. a mixture containing (A) an organopolysiloxane having at least 0.1 percent by weight of Si-bonded hydroxyl groups and at least 50 mol percent of monoorganosiloxane units (RSiO.sub.3/2), (B) an organosiloxane containing from 2 to 10 silicon atoms per molecule, in which substantially all the silicon valences which are not satisfied by siloxane oxygen atoms, are satisfied by SiC-bonded hydrocarbon radicals, and having on the average at least two such hydrocarbon radicals for each silicon atom and at least one of the siloxanes (A) and/or (B) has an average of at least one SiC-bonded vinyl group, and (C) an acid activated bleaching clay; wherein the water released during the heating step by the condensation of Si-bonded hydroxyl groups is retained in the reactive mixture.