Abstract: A fuel cell separator is molded from a resin composition containing specific amounts of graphite, thermosetting resin and internal release agent. The graphite is a synthetic graphite powder prepared by graphitizing lump coke. The thermosetting resin is a mixture of phenolic novolac, benzoxazine and polycarbodiimide resins. The molded separator does not need to be machined, has a significantly improved electrical conductivity, heat resistance and mechanical strength, and even when very thin is resistant to breakage during molding and fuel cell assembly.

Abstract: A separator for fuel cell, obtained by molding a resin composition comprising 100 parts by weight of a graphite, 15 to 30 parts by weight of a bisphenol A type epoxy resin, 2 to 4 parts by weight of a phenolic resin, and 1 to 10 parts by weight of a polycarbodiimide resin, which, unlike the prior art, is superior in moldability, electrical conductivity and mechanical strength and causes no cracking during molding even when made in a small thickness.

Abstract: A fuel cell separator is molded from a resin composition containing specific amounts of graphite, thermosetting resin and internal release agent. The graphite is a synthetic graphite powder prepared by graphitizing lump coke. The thermosetting resin is a mixture of phenolic novolac, benzoxazine and polycarbodiimide resins. The molded separator does not need to be machined, has a significantly improved electrical conductivity, heat resistance and mechanical strength, and even when very thin is resistant to breakage during molding and fuel cell assembly.

Abstract: The present invention provides: an electroconductive resin composition comprising: (A) a liquid crystal polyester resin capable of forming an anisotropic melt phase, in an amount of 100 parts by weight, (B) a carbodiimide compound in an amount of 0.01 to 30 parts by weight, (C) an electroconductive carbon powder in an amount of 50 to 3,000 parts by weight, and (D) a filler in an amount of 0 to 10,000 parts by weight; a fuel cell separator made of the above electroconductive resin composition; a process for producing the above fuel cell separator; and a solid polymer type fuel cell using the above fuel cell separator. The electroconductive resin composition alleviates the problems of the prior art, can be mass-produced, and is superior in high temperature resistance and hydrolysis resistance.

Abstract: The present invention provides a separator for fuel cell which alleviates the problems of the prior art, which has high conductivity, high gas impermeability and high strength, and which can be produced easily. The separator for fuel cell according to the present invention is a molding comprising a conductive carbon powder and a polymer compound, wherein the conductive carbon powder in the molding has an aspect ratio of 4 to 60.

Abstract: The present invention provides a separator for a polymer electrolyte fuel cell, having, at the surface contacting with the electrode of the fuel cell, a surface roughness of Ra=0.1 to 10 &mgr;m when measured by a surface roughness tester having a probe of 5 &mgr;m in front end diameter; and a process for producing the above separator for a polymer electrolyte fuel cell, which process comprises immersing a molding of a separator for a polymer electrolyte fuel cell, in an acidic solution. The above separator for a polymer electrolyte fuel cell alleviates the problems of the prior art and has low contact resistance at the interface with the electrode of the fuel cell.

Abstract: The present invention provides: a separator for a polymer electrolyte fuel cell, interposed between the gas diffusion electrodes of the fuel cell and having, in at least one side, a groove for supply of an oxidizing agent or a fuel gas, which separator is made of a carbon composite material comprising (a) 100 parts by weight of an expanded graphite powder and (b) 10-45 parts by weight of a thermosetting resin dispersed in the expanded graphite powder (a), wherein the expanded graphite powder has an average particle diameter of 5-12 &mgr;m and at least 80% of the total particles of the expanded graphite powder have particle diameters of 0.1-20 &mgr;m. The separator for polymer electrolyte fuel cells according to the present invention is lightweight, can be grooved precisely and easily, and has a high gas barrier property, strength and electroconductivity.

Abstract: The present invention provides a carbon composite material which is a molded material comprising (a) an expanded graphite powder and (b) a thermoplastic resin or a thermosetting resin or a fired product of the thermosetting resin, and the expanded graphite powder (a) being dispersed in the component (b), wherein the expanded graphite powder has an average particle diameter of 5-12 .mu.m and at least 80% of the total particles of the expanded graphite powder have particle diameters of 0.1-20 .mu.m; and a process for producing a carbon composite material, which comprises mixing and dispersing a thermoplastic or thermosetting resin and the expanded graphite powder as mentioned above, and then pressure-molding the resulting mixture at room temperature to 400.degree. C., or a process for producing a carbon composite material, which comprises mixing and dispersing a thermosetting resin and the expanded graphite powder as mentioned above, pressure-molding the resulting mixture at room temperature to 400.degree. C.

Abstract: The present invention providesa carbon composite material which is a molded material comprising (a) an expanded graphite powder and (b) a thermoplastic resin or a thermosetting resin or a fired product of the thermosetting resin, and the expanded graphite powder (a) being dispersed in the component (b); wherein the expanded graphite powder has an average particle diameter of 5-12 .mu.m and at least 80% of the total particles of the expanded graphite powder have particle diameters of 0.1-20 .mu.m; anda process for producing a carbon composite material, which comprises mixing and dispersing a thermoplastic or thermosetting resin and the expanded graphite powder as mentioned above, and then pressure-molding the resulting mixture at room temperature to 400.degree. C., or a process for producing a carbon composite material, which comprises mixing and dispersing a thermosetting resin and the expanded graphite powder as mentioned above, pressure-molding the resulting mixture at room temperature to 400.degree. C.