Foaming of the foamable silicone rubber composition, curing method and foamed silicone rubber cured

摘要

PURPOSE:To obtain the title composition wherein TiO2 powder increases the ability to absorb microwaves and the foaming and curing can be performed by ultrahigh-frequency vulcanization, by mixing a diorganopolysiloxane with a silica filler, a TiO2 powder, a blowing agent and a curing agent. CONSTITUTION:100 pts.wt. diorganopolysiloxane of the formula [wherein R is a (substituted) monovalent hydrocarbon group; and a=1.95-2.05], having an average degree of polymerization of 3000-30000, is mixed with 10-300 pts.wt. fine powdery silica filler, 5-200 pts.wt. TiO2 powder (desirably rutile) of a mean particle diameter =30mum, 1-10 pts.wt. blowing agent (e.g. azobisisobutyronitrile) and a curing agent (e.g. dicumyl peroxide). A foam having fine uniform cells can be obtained because the TiO2 powder can increase the ability to absorb microwaves and can generate heat when irradiated with microwaves, and therefore the composition can be vulcanized by ultrahigh-frequency waves.