Sealing material for solid polymer fuel cell separator

Abstract

A sealing material for sealing the edges on at least one side of a solid polymer fuel cell separator is provided. This sealing material includes (A) an organopolysiloxane with at least two alkenyl groups bonded to silicon atoms within each molecule, (B) an organohydrogenpolysiloxane with at least two hydrogen atoms bonded to silicon atoms within each molecule, (C) a fumed silica with a specific surface area of 50 to 250 m2/g which has undergone surface treatment with at least two different surface treatment agents, and (D) an addition reaction catalyst. This sealing material displays excellent moldability, heat resistance and elasticity, has a compression set within air and within an acidic aqueous solution which can be suppressed to a low value, and produces an excellent seal, particularly in an acidic aqueous solution.

Dependencies are inferred from the claim text.