| abstract |
Silicone mold compositions are provided which exhibit low durometer and high tear strength properties and comprise a main filler of precipitated silica and a reinforcing co-filler selected from acicular CaSiO₃ fillers, fumed aluminum oxide fillers, and spherical ceramic fillers. The co-fillers have large surface areas and small particle sizes. The co-fillers are used with alkoxy silane cross-linking agents of the formula (RO)₄Si, particularly n-propylsilicate. Two-part silicone cure systems are provided which enable the rapid achievement of full die B tear strengths without the need for prolonged aging of these materials. |