Composition, foamed silicone elastomer formed therefrom, and methods of formation

A composition for forming a foamed silicone elastomer is disclosed. The composition comprises: (A) an organopolysiloxane having at least two silicon-bonded ethylenically unsaturated groups per molecule; (B) an organohydrogensiloxane having at least two silicon-bonded hydrogen atoms per molecule; (C) a hydrosilylation catalyst; (D) a chemical blowing agent; and (E) a physical blowing agent. The hydrosilylation catalyst (C) is present in a catalytically effective amount. The chemical blowing agent (D) has at least one hydroxyl (OH) group, and is present in an amount to provide a OH content > 0 and > 500 parts per million (ppm). The physical blowing agent (E) undergoes a phase change from a liquid to a gaseous state during exposure to atmospheric pressure and a temperature ≥ 0 DEG C. The blowing agents (D) and (E) are different from one another. A foamed silicone elastomer, and methods of forming the composition and foamed silicone elastomer are also disclosed.