Millable silicone rubber composition, millable silicone rubber sponge, and method for manufacturing the same

摘要

A method for producing a millable silicone rubber sponge, the following components (A) to (E): (A) an organopolysiloxane having a polymerization degree of 3,000 or more having at least two alkenyl groups in one molecule, (B) reinforcing silica, (C) Thermally expandable microcapsules having an expansion initiation temperature of 90 to 150° C. and shrinking by 20% or more from the maximum expansion volume by heating at 200° C. for 5 minutes, (D) curing agent, (E) softening agent: decomposition initiation temperature of 180° C. A method for producing a millable silicone rubber sponge having a rolling rate of 20% or more, wherein a silicone rubber composition containing the above solid, high-temperature decomposing organic foaming agent, which starts to decompose after curing of component (A), is heat-treated at 200°C or higher .