PROCESS FOR CONTROLLING THE RATE OF PLATINUM INDUCED ADDITION REACTION OF SILICON BONDED HYDROGEN ATOMS TO ORGANOPOLYSILOXANES CONTAINING ALAPHATIC UNSATURATION

摘要

ABSTRACT OF THE DISCLOSUREA process for controlling the rate of addition of silicon bondedhydrogen atoms to organopolysiloxanes containing aliphatic unsaturation isprovided herein. The process comprises mixing (1) an organopolysiloxanecontaining silicon bonded hydrogen atoms and/or (2) an organopolysiloxanecontaining at least 50 silicon atoms per molecule and having aliphaticallyunsaturated groups with at least one organosilicon compound of the formulaCH2=CHR2SiO(SiR2O)nSiR2CH=CH2in which R is a hydrocarbon radical or a substituted hydrocarbon radicalfree of aliphatic unsaturation and n is a number of from 0 to 6 prior tocombining the organopolysiloxanes (1) and (2) in the presence of a platinumcatalyst. The composition thus obtained has a substantially longer pot-life while only slightly extending the curing time.