Powdered MQ Resin−Platinum Complexes and Their Use as Silicone-Soluble Hydrosilylation Cure Catalysts

Moldable poly(dimethylsiloxane) formulations are described which use so-called MQ resins as reinforcing fillers. These formulations employ platinum-catalyzed hydrosilylation as the cure reaction. The platinum catalysts were prepared by spray-drying solutions composed of vinyl-containing MQ resins with platinum(0) complexes of divinyltetramethydisiloxane (MviMvi) ligands. The spray-dried mixture was a white, free-flowing powder containing 1% by weight platinum where the platinum was Pt(0) and coordinated to the vinyls of the MQ resin. Molecular MQ resin−platinum complexes, free of platinum crystallites were obtained by spray-drying but not by vacuum oven treatment of solutions of resin and Pt(MviMvi)x complexes. Oven-prepared, platinum-containing resins contained platinum crystallites. The platinum-containing spray-dried MQ resin was a useful catalyst to cure moldable poly(dimethylsiloxane) formulations. Higher catalytic activity was observed for resin without platinum crystallites. Analyses of the platinu...