Fire resistant thermoplastic silicone vulcanizates

摘要

A composition comprising a polyolefin, a polyorganosiloxane having at least two alkenyl groups per molecule, and calcium silicate where the polyorganosiloxane is cured after mixing using an organohydrido silicon compound and a hydrosilation catalyst to create a thermoplastic vulcanizate, provides excellent fire resistance. In particular such compositions when tested by burning at 40 to 88 kW/m² external flux generate significantly less heat and smoke, and generate tougher chars compared to polyolefins alone, or mixtures of thermoplastic polyolefin resin, polyorganosiloxane and calcium silicate where the composition is not cured after mixing.