Polymer electrolyte fuel-cell separator sealing rubber composition
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsNoriyuki Meguriya, Yujiro Taira
Life of this patent
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Abstract
A rubber composition comprising (A) an organopolysiloxane end-capped with alkenyldialkylsiloxy, dialkenylalkylsiloxy or trialkenylsiloxy radicals and free of aliphatic unsaturation on any side chain, (B) an organopolysiloxane containing at least three alkenyl radicals on molecular side chains, (C) an organohydrogenpolysiloxane having at least three Si—H radicals, (D) fumed silica, and (E) an addition reaction catalyst forms a seal member having improved strength and reduced compression set and useful for sealing a polymer electrolyte fuel-cell separator.
Claims6
A rubber composition for sealing a periphery of at least one side of a polymer electrolyte fuel-cell separator, comprising, in parts by weight,
- (A) 70 to 95 parts of an organopolysiloxane which is blocked at either end of the molecular chain with a radical independently selected from the group consisting of alkenyldialkylsiloxy, dialkenylalkylsiloxy and trialkenylsiloxy radicals, and which does not contain an aliphatic unsaturated monovalent hydrocarbon radical attached to a silicon atom on any molecular side chain,
- (B) 5 to 30 parts of an organopolysiloxane containing at least three alkenyl radicals each attached to a silicon atom on molecular side chains per molecule,
- (C) 0.5 to 20 parts, per 100 parts of components (A) and (B) combined, of an organohydrogenpolysiloxane having at least three hydrogen atoms each attached to a silicon atom per molecule,
- (D) 10 to 40 parts, per 100 parts of components (A) and (B) combined, of fumed silica having a specific surface area of 50 to 400 m2/g, and
- (E) a catalytic amount of an addition reaction catalyst.
Dependencies are inferred from the claim text.