Novel organosiloxane inhibitors for hydrosilation reactions

摘要

Certain liquid polydiorganosiloxanes wherein each molecule contains at least one sequence of 2 or more vinyl radicals bonded to non-terminal silicon atoms extend the working time at 25 DEG C. of organosiloxane compositions that cure by a platinum catalyzed hydrosilation reaction without adversely affecting the cure rate of the composition at temperatures of about 100 DEG C. and above. The polydiorganosiloxane is prepared by the acid-catalyzed polymerization of the corresponding cyclic polydiorganosiloxanes in the presence of a chain-terminating organosilicon reactant.