Patent ID: 6030919
Filing Date: 2000-02-29
Classification: C08G

Abstract:
A method for making a platinum hydrosilylation catalyst, which comprises the steps of:1) agitating a mixture comprising haloplatinic acid, alkenylpolysiloxane and cycloalkylpolysiloxane at a temperature and for a duration which is sufficient to effect the equilibration of the resulting organopolysiloxane-platinum halide reaction product,2) treating the equilibrate of step 1) with sufficient base to effect the substantial removal of halogen chemically combined with platinum, and,3) filtering the mixture of 2) to provide recovery of a platinum hydrosilylation catalyst,where prior to the equilibration of the initial mixture of 1), there is utilized per mole of haloplatinic acid, sufficient moles of alkenylpolysiloxane to provide at least one mole of alkenylsiloxy unit, per/atom of platinum, and sufficient cycloalkylpolysiloxane, to provide from about 0.3 mole to about 20 moles of cycloalkylpolysiloxane, per mole of alkenylpolysiloxane.