HIGH-STRENGTH SILICONE RUBBER PARTICULATE

摘要

HIGH-STRENGTH SILICONE RUBBER PARTICULATE A hydrophobic silica is prepared by mixing and and heating a mixture of (a) 100 weight parts wet-method silica and (b) 1 to 100 weight parts organopolysiloxane represented by the following average unit formula R1aR2bSiO(4-a-b)/2' wherein R1 is a monovalent hydrocarbon group, R2 is the hydrogen atom, ? is from 1 to 3 inclusive, and b is from zero to 1 inclusive, with the provisos that a + b is from 1.90 to 2.10 inclusive and b/(a + b) is from zero to 0.45 inclusive. This hydrophobic silica is used to prepare a high-strength silicone rubber particulate by mixing with a curable diorganopolysiloxane and curing the mixture in the form of particulates. A preferred manner of making the particulates is by emulsifying the mixture of hydrophobic silica and curable diorganopolysiloxane in water, then spraying the emulsion and remove the water, giving microparticles of high-strength silicone rubber.