Electrically Conducting Curable Resin Composition, Cured Product Thereof and Molded Article of the Same

Abstract

There is provided a curable composition which can give a cured product having excellent physical properties and is particularly useful as a material for the separator of a fuel cell such as polymer electrolyte fuel cell. The electrically conducting curable resin composition of the present invention comprises (A) a hydrocarbon compound having a plurality of carbon-carbon double bonds, (B) an elastomer excluding the component (A), and (C) a carbonaceous material.

1 . An electrically conducting curable resin composition comprising (A) a hydrocarbon compound having a plurality of carbon-carbon double bonds, (B) an elastomer excluding the component (A), and (C) a carbonaceous material. 
     
     
         2 . The electrically conducting curable resin composition as defined in  claim 1 , wherein the hydrocarbon compound (A) having a plurality of carbon-carbon double bonds is a polymer having carbon-carbon double bonds in the side chain. 
     
     
         3 . The electrically conducting curable resin composition as defined in  claim 2 , wherein the polymer having carbon-carbon double bonds in the side chain is a polymer having carbon-carbon double bonds in the side chain and containing 60 mol % or more of a saturated monomer unit in the main chain. 
     
     
         4 . The electrically conducting curable resin composition as defined in  claim 3 , wherein the polymer having carbon-carbon double bonds in the side chain and containing 60 mol % or more of a saturated monomer unit in the main chain is obtained by polymerizing a diene compound as the main monomer. 
     
     
         5 . The electrically conducting curable resin composition as defined in  claim 4 , wherein the diene compound is at least one member selected from butadiene, pentadiene and isoprene. 
     
     
         6 . The electrically conducting curable resin composition as defined in  claim 1 , wherein the hydrocarbon compound (A) having a plurality of carbon-carbon double bonds is at least one member selected from 1,2-polybutadiene, 3,4-polyisoprene and a styrene-isoprene copolymer. 
     
     
         7 . The electrically conducting curable resin composition as defined in  claim 1 , wherein the hydrocarbon compound (A) having a plurality of carbon-carbon double bonds is a polymer comprising 60 mol % or more of a monomer unit represented by the following formula (1) or (2): 
       
         
           
           
               
               
           
         
       
     
     
         8 . The electrically conducting curable resin composition as described in  claim 1 , wherein the elastomer (B) is one member selected from the group consisting of a hydrogenated acrylonitrile butadiene rubber, an ethylene octene copolymer, an ethylene butene copolymer, an ethylene propylene rubber, a fluororubber, an isoprene rubber, a silicone rubber, an acryl rubber, a norbornene rubber and a butyl rubber, or a combination of two or more members selected therefrom. 
     
     
         9 . The electrically conducting curable resin composition as defined in  claim 1 , wherein the elastomer (B) is one member selected from the group consisting of a hydrogenated acrylonitrile butadiene rubber, an ethylene octene copolymer, an ethylene butene copolymer, an ethylene propylene rubber, an isoprene rubber, an acryl rubber, a norbornene rubber and a butyl rubber, or a combination of two or more members selected therefrom. 
     
     
         10 . The electrically conducting curable resin composition as defined in  claim 1 , wherein the carbonaceous material (C) is one member selected from natural graphite, artificial graphite, expanded graphite, carbon black, carbon fiber, vapor grown carbon fiber with a fiber diameter of 0.05 to 10 μm and a fiber length of 1 to 500 μm, and carbon nanotube with a fiber diameter of 0.5 to 100 nm and a fiber length of 0.01 to 10 μm, or a combination of two or more members selected therefrom. 
     
     
         11 . The electrically conducting curable resin composition as defined in  claim 1 , wherein the carbonaceous material (C) has a powder specific electrical resistance of 0.1 Ωcm or less in the direction at right angles to the applied pressure direction in the state of being pressurized to have a bulk density of 1 g/cm 3 . 
     
     
         12 . The electrically conducting curable resin composition as defined in  claim 1 , wherein the carbonaceous material (C) comprises from 0.05 to 10% by weight of boron. 
     
     
         13 . The electrically conducting curable resin composition as defined in  claim 1 , wherein the mass ratio between the hydrocarbon compound having a plurality of carbon-carbon double bonds as the component (A) and the elastomer as the component (B) is from 20 to 98% by weight: from 80 to 2% by weight and assuming that the sum of the component (A) and the component (B) is 100 parts by weight, the carbonaceous material as the component (C) is contained at a proportion of 40 to 1,900 parts by weight per the sum of 100 parts by weight. 
     
     
         14 . The electrically conducting curable resin composition as defined in  claim 1 , which further comprises (D) a reactive monomer. 
     
     
         15 . An electrically conducting cured product obtained by curing the electrically conducting curable resin composition defined in  claim 1 . 
     
     
         16 . An electrically conducting cured product obtained by forming the electrically conducting curable resin composition defined in  claim 1  by any one method of compression molding, transfer molding, injection molding and injection-compression molding. 
     
     
         17 . The electrically conducting cured product as defined in  claim 15 , wherein the volume resistivity according to JIS K7194 is 2×10 −2  Ωcm or less. 
     
     
         18 . The electrically conducting cured product as defined in  claim 15 , wherein the flexural strength according to JIS K6911 is 30 MPa or more. 
     
     
         19 . A method for producing an electrically conducting cured product, the method comprising forming the electrically conducting curable composition defined in  claim 1  by any one method of compression molding, transfer molding, injection molding and injection-compression molding. 
     
     
         20 . An electrically conducting molded article comprising the electrically conducting curable resin composition defined in  claim 1  or the electrically conducting cured product defined in  claim 15 . 
     
     
         21 . A fuel cell separator or a current corrector or electrode for battery, in which a flow channel for flowing a gas is formed on both surfaces or one surface, comprising the electrically conducting curable resin composition defined in  claim 1  or the electrically conducting cured product defined in  claim 15 . 
     
     
         22 . A method for producing a fuel cell separator or a current collector or electrode for battery, in which a flow channel for flowing a gas is formed on both surfaces or one surface, the method comprising forming the electrically conducting curable resin defined in  claim 1  by any one method of compression molding, transfer molding, injection molding and injection-compression molding. 
     
     
         23 . A fuel cell separator in which a flow channel for flowing a gas is formed on both surfaces or one surface and which is obtained from the electrically conducting curable resin composition defined in  claim 1  or the electrically conducting cured product defined in  claim 15 , wherein the volume resistivity according to JIS K7194 is 2×10 −2  Ωcm or less, the resistivity in the penetration direction is 2×10 −2  Ωcm or less and the flexural strength according to JIS K6911 is 30 MPa or more.