Separator for fuel cell, process for producing the same, and material therefor

摘要

This invention relates to a fuel cell separator of excellent electrical conductivity, gas impermeability and strength. The composition for a fuel cell separator of this invention comprises a resin binder with a viscosity of 0.01-0.5 Pa .s at 150° C. and a viscosity of 3 Pa.s or more at 25° C. and graphite particles at a weight ratio of 1:(5-15) and a curing accelerator. The resin binder is exemplified by an epoxy resin binder composed of an epoxy resin and a curing agent for the epoxy resin. The process for producing the fuel cell separator of this invention is practiced by kneading and molding the aforementioned composition for a fuel cell separator and curing above the curing temperature of the composition. The fuel cell separator of this invention to be obtained by the aforementioned process shows a bulk density of 1.90 g/cm3 or more, a sheet resistance (areal pressure, 0.5 MPa) of 40 m OMEGA cm2 or less, a gas permeability of 1x10-14 cm2 or less and a flexural strength of 30 MPa or more.