Toray Industries, Inc.

Hiroaki Fukui

Kishio Miwa

Kazuharu Shimizu

Fumiaki Noma

An electroconductive integrated substrate and a process for producing the same, which comprises a porous carbonaceous plate having a large number of pores and gas permeability, and a gas unpermeable electroconductive plate laminated on the porous carbonaceous plate and integrally bonded thereto by thermoplastic resin which is present substantially only in the pores of the porous carbonaceous plate. It is preferred to use thermoplastic resin having a melting viscosity of from 10.sup.2 to 10.sup.6 poises, and a gas permeable porous carbonaceous plate having a mean pore diameter of from 20 to 150 .mu.m and a porosity of from 40 to 85%. The porous carbonaceous plate and the gas impermeable electroconductive plate are laminated one upon the other with a thermoplastic resin film interposed therebetween, and the film is melted to bond the plates together. The integrated substrate obtained has an electrical resistance of not greater than 7 m.OMEGA., preferably not greater than 1.5 m.OMEGA., at the bonded surface in the thickness direction thereof.

Electroconductive integrated substrate and process for producing the same

A porous electrode substrate for fuel cell and a process for producing the same, which contains 35 to 60% carbonized resin by weight, and has pores with a mean pore size of 20 to 60 .mu.m and a porosity of 60 to 80%, and a compression ratio of 20% or less. Chopped carbon fibers with fiber lengths of 3 to 20 mm and fiber diameters of 4 to 9 .mu.m are dispersed in random directions within substantially 2-dimensional plane, and bound with an organic binder to make an carbon fiber mat. The carbon fiber mat is impregnated with a resin to make prepreg and hot pressing the prepreg under a temperature of 120.degree. to 200.degree. C. and a pressure of 2 to 10 kg/cm.sup.2. Then, the press molded product is carbonized by heat treatment under a temperature of 1300.degree. to 3000.degree. C. in an inert atmosphere or in vacuum to obtain an electrode substrate excellent in various characteristics such as gas permeability, flexural strength, compression strength, etc. Further, for improvement of electroconductivity, it is preferable to use a mixture of a curable resin and a non-curable resin as the resin impregnated into the carbon fiber mat.

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Shiga, Japan

Hiroaki Fukui