Patent ID: 7741412

Claim:
A curable organopolysiloxane composition, consisting of: (A) an organopolysiloxane containing at least one alkenyl group bonded to a silicon atom at a molecular chain terminal within each molecule, represented by an average composition formula (1) shown below: R a R 1 b SiO (4-a-b)/2 (1) wherein, R represents an alkenyl group, R 1 represents a substituted or unsubstituted monovalent hydrocarbon group that contains no aliphatic unsaturated bonds, a represents a number from 0.0001 to 0.2, b represents a number from 1.7 to 2.2, and a+b represents a number within a range from 1.9 to 2.4, (B) an organohydrogenpolysiloxane, which contains, within each molecule, at least one hydrogen atom bonded to a silicon atom at a molecular chain terminal, and at least two hydrogen atoms bonded to non-terminal silicon atoms within a molecular chain, and which satisfies a formula (2) shown below: 0.15≦α/β<0.25 (2) wherein, α represents a number of hydrogen atoms bonded to non-terminal silicon atoms within a molecular chain, and β represents a total number of silicon atoms within said component (B), in sufficient quantity to provide from 0.1 to 5 hydrogen atoms bonded to silicon atoms within said component (B) per alkenyl group bonded to a silicon atom within said component (A), (C) an effective quantity of a platinum-based catalyst, and (D) at least one member selected from the group consisting of reaction retarding agents, flame retardancy imparting agents, dyes, hollow fillers, silsesquioxanes, silicone rubber powder, silicone resin powder, and inorganic fillers selected from the group consisting of fumed silica, precipitated silica, fumed titanium dioxide, magnesium oxide, zinc oxide, iron oxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, zinc carbonate, layered mica, carbon black, diatomaceous earth, and glass fibers and fillers treated with a hydrophobic agent.