Curable organosiloxane compositions containing organotitanate/microencapsulated platinum co-catalysts

The presence of both an organotitanium compound and a microencapsulated platinum-containing hydrosilation catalyst in organosiloxane compositions curable by a hydrosilation reaction not only increases the heat stability of elastomers prepared from the composition, but also unexpectedly increases the cure rate of the compositions. In addition to the platinum-containing and organotitanium catalysts, the curable compositions comprise an organohydrogenpolysiloxane curing agent and a liquid organopolysiloxane containing an average of at least two ethylenically unsaturated hydrocarbon radicals per molecule.