Abstract: A cement mold-making silicone rubber composition is provided comprising (A) 100 parts by weight of a polyorganosiloxane having at least two silicon-bonded monovalent aliphatic unsaturated hydrocarbon groups in a molecule, (B) a polyorganohydrogensiloxane having at least three silicon-bonded hydrogen atoms in a molecule, in such an amount as to provide 0.1-5 silicon-bonded hydrogen atoms per monovalent aliphatic unsaturated hydrocarbon group in component (A), (C) a platinum base compound in such an amount as to provide 1-100 ppm of platinum atoms based on the weight of component (A), (D) 5-60 parts by weight of finely divided silica having a specific surface area of at least 50 m2/g, and (E) 0.1-100 parts by weight of coal ash and/or pozzolan powder.

Abstract: A cement mold-making silicone rubber composition is provided comprising (A) 100 parts by weight of a polyorganosiloxane having at least two silicon-bonded monovalent aliphatic unsaturated hydrocarbon groups in a molecule, (B) a polyorganohydrogensiloxane having at least three silicon-bonded hydrogen atoms in a molecule, in such an amount as to provide 0.1-5 silicon-bonded hydrogen atoms per monovalent aliphatic unsaturated hydrocarbon group in component (A), (C) a platinum base compound in such an amount as to provide 1-100 ppm of platinum atoms based on the weight of component (A), (D) 5-60 parts by weight of finely divided silica having a specific surface area of at least 50 m2/g, and (E) 0.1-100 parts by weight of coal ash and/or pozzolan powder.