Abstract: 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° 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.

Abstract: 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° 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.