Sealing material for polymer electrolyte fuel-cell separator

摘要

A sealing material comprises (weight parts): (a) organopolysiloxane (100) containing two or more alkenyl groups/molecule; (b) resinous copolymer (5-50) comprising siloxane units and silica units; (c) organohydrogen polysiloxane (0.5-20) containing two or more hydrogen atoms/molecule; (d) fumed silica (10-30); and (e) catalytic amount of addition reaction catalyst. A sealing material comprises (weight parts): (a) organopolysiloxane (100) containing at least two alkenyl groups/molecule each attached to silicon atom; (b) resinous copolymer (5-50); (c) organohydrogen polysiloxane (0.5-20) containing at least two hydrogen atoms/molecule each attached to Si; (d) fumed silica (10-30); and (e) catalytic amount of addition reaction catalyst. The resinous copolymer comprises siloxane units (R 3SiO 1/2) and silica units (SiO 2) in a molar ratio of 0.5:1-1.5:1, where R is monovalent hydrocarbon group, and 5 X 10 ->2>-1 X 10 ->4>mol/g of vinyl groups. The fumed silica has specific surface area of 150-400 m 2>/g. Independent claims are also included for the following: (1) Preparation of sealing material; (2) Use of sealing material for providing an edge seal of polymer electrolyte fuel cell separator; (3) Molded edge seal for polymer electrolyte fuel cell separator; and (4) Assembly of polymer electrolyte fuel cell separator and an edge seal.