Process for producing electrode substrate for use in fuel cells

Claim 1

A process for producing a porous carbonaceous electrode substrate provided with a group of elongated holes for reactant gases for fuel cells comprising the steps of (a) introducing into a metal mold of predetermined shape and dimension, in order, (1) a first amount of a first material for producing said porous carbonaceous electrode substrate comprising 10 to 50% by weight of a filling material which is short carbon fibers or granular activated carbon, 20 to 40% by weight of a binding material which is selected from the group consisting of phenol resin, epoxy resin, furfuryl alcohol resin, pitch derived from petroleum or coal and mixtures thereof and shows a carbonization yeild of 30 to 75% by weight, and 20 to 50% by weight of a micropore-regulating material which is selected from the group consisting of polyvinylalcohol, polyvinylchloride, polystyrene, polyethylene, polypropylene, sucrose and mixtures thereof, (2) a high polymeric substance in the shape of a cloth-like fabric or a grating-like molding for forming the elongated holes, which substance is selected from the group consisting of polyethylene, polypropylene, polystyrene, polyvinylalcohol and polyvinylchloride and gives a carbonization yield of lower than 30% by weight and (3) a second amount of said first material for producing said porous carbonaceous electrode substrate, (b) press-molding the thus provided materials in the metal mold heated to from 70° to 170° C. under a molding pressure of from 5 to 100 kg/cm 2 for from 1 to 160 min, (c) subjecting the thus press-molded material to after-hardening, and (d) then further calcinating the thus after-hardened material in an inert atmosphere at a temperature from 800° to 3,000° C. to thermal-decompose a larger part of said high polymeric substance to be carbonized, thereby forming said porous carbonaceous electrode substrate provided with said group of elongated holes opening from one side to the opposite side of the electrode substrate through nearly the central region of the thickness of the substrate.