KR20030036887A - Conductive curable resin composition and separator for fuel cell - Google Patents

Abstract

The present invention comprises a curable resin composition containing (A) an elastomer having a Mooney viscosity (ML _{1 + 4} (100 ° C.)) of 25 or more at a ratio of 2-80 wt%, and (B) a carbon material, comprising (A) component It provides a conductive curable resin composition having a weight ratio of component (B) of 70-5: 30-95. The curable resin composition of component (A) is preferably 0.2 to 80 parts by weight of (A1) elastomer, 20 to 98 wt% of (A2) radically reactive resin and 100 parts by weight of (A3) (A1 + A2). -10 parts by weight of organic peroxide. Moreover, the manufacturing method of electroconductive curable resin by shaping | molding and hardening of electroconductive curable resin composition, and the fuel cell, battery component, electrode, or heat sink which were obtained by this are provided.

Description

Conductive curable resin composition and separator for fuel cell {CONDUCTIVE CURABLE RESIN COMPOSITION AND SEPARATOR FOR FUEL CELL}

Conventionally, metals and carbon materials have been used for applications requiring high conductivity. In particular, the carbon material is a corrosion-free material having metal properties, and has excellent heat resistance, lubricity, thermal conductivity, and durability, and has played an important role in fields such as electronics, electrochemistry, energy, transport equipment, and the like. In addition, even in a composite material made of a combination of a carbon material and a polymer material, progress has been made to a surprising level to achieve high performance and high performance. In particular, the degree of freedom in molding processability is improved by the compounding with the polymer material, which is one reason that carbon materials have been developed in various fields requiring conductivity.

In recent years, in view of environmental problems and energy-related problems, attention has been paid to a clean power generation apparatus in which a fuel cell generates electricity by reverse reaction of electrolysis of water using hydrogen and oxygen, and does not generate emissions other than water. Carbon materials and polymer materials can also play an important role in these applications. Solid polymer fuel cells are most promising for automotive and consumer use when operated at low temperatures. Such fuel cells can achieve high-power generation by stacking a single cell consisting of a polymer solid electrolyte, a gas diffusion electrode, a catalyst and a separator.

Separators used to partition a single cell are generally grooved for the supply of fuel gas and oxidant gas and not only require good gas impermeability to completely separate the gas, but also reduce the internal resistance. City is required. In addition, excellent thermal conductivity, durability and strength are required.

In order to achieve these demands, such separators have conventionally been studied for both metal and carbon materials. In the corrosion resistance problems associated with metals, attempts were made to coat precious metals or carbon on surfaces, but it was not possible to achieve sufficient durability, and coating costs were also a problem.

On the other hand, carbon materials have also been studied in various ways, for example, molded articles obtained by press-molding expanded graphite sheets, molded articles obtained by impregnating and curing resins in carbon sintered bodies, and mixed glassy carbon, carbon powder and resin obtained by firing thermosetting resins. The molded article obtained by post-molding is mentioned as an example.

For example, Japanese Patent Application Laid-Open No. 8-222241 discloses isotropic graphite materials obtained by adding a binder to carbonaceous powder, forming a CIP after heat mixing, firing and graphitizing it in order to secure reliability and dimensional accuracy. The complicated process of impregnating a thermosetting resin in the hardening process, hardening | curing, and engraving a groove | channel by a cutting process is started. In addition, Japanese Laid-Open Patent Publication No. 60-161144 discloses that a paper containing carbon powder or carbon fiber is impregnated with a thermosetting resin, followed by laminating, pressing, and firing the paper. Japanese Laid-Open Patent Publication No. 2001-68128 discloses injection molding a phenol resin into a separator-shaped mold and firing it. Such calcined material exhibits high conductivity, but has a long time required for firing and thus lowers productivity. When cutting is required, mass productivity is lowered and costs are high, which makes it difficult to supply materials in the future.

On the other hand, a molding molding method is considered as a means for lowering the cost and lowering the cost, and a material applicable to this is a composite of a carbon-based filler and a resin. For example, Japanese Laid-Open Patent Publication No. 58-53167, Japanese Laid-Open Japanese Patent Laid-Open Publication No. 60-37670, Japanese Patent Laid-Open Publication No. 60-246568, Japanese Patent Laid-Open Publication No. 64-340 and Japanese Patent Laid-Open Publication No. Hei 6-22136 each disclose thermosetting resins such as phenol resins, Japanese Patent Laid-Open Publication No. 57-42157 discloses a bipolar separator made of a thermosetting resin such as epoxy resin and a conductive material such as graphite, and Japanese Unexamined Patent Application Publication No. Hei 1-311570 The publication discloses a separator composed of a mixture of expanded graphite and carbon black in a thermosetting resin such as a phenol resin or a furan resin. It is disclosed.

Separators using mixtures of carbon-based fillers and resins require much higher amounts of carbon-based fillers to express high conductivity, but sufficiently high conductivity because large amounts of resin must be added to maintain mold formability. Is difficult to obtain. In addition, in order to improve the thickness accuracy, which is a particularly important characteristic of the fuel cell separator, an attempt has been made to form the composition into a sheet having excellent precision by rolling or the like, and to harden the composition into a fuel cell separator, but the content of the carbon-based filler is high. It did not become a uniform sheet, and content of resin used as a matrix was increased. As a result, sufficient conductivity and thermal conductivity were not expressed.

To obtain high conductivity. In the case of including the firing step of heating the molded body at a high temperature of 1000-3000 ° C. for a long time, the time required for manufacturing increases, and the manufacturing process becomes complicated, resulting in a further increase in cost.

The object of the present invention which has been achieved in view of such a situation is to provide a conductive curable resin composition which is excellent in high filling properties of the conductive filler and excellent in molding processability. It is an object of the present invention to provide a fuel cell separator, a battery component, an electrode or a heat dissipation plate having excellent conductivity and heat dissipation, which is obtained by molding the composition on a sheet in an uncured state and curing it into a separator shape for fuel cells.

Related reference

This application entails a priority claim on the date of application under 35 USC § 119 (e) (1) of US Provisional Application No. 60 / 316,983, filed on September 5, 2001, under the provisions of 35 USC § 111 (b). Filed under USC § 112 (a).

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive curable resin composition excellent in conductivity and heat dissipation, and more particularly to a separator for fuel cells, a battery component, an electrode or a heat sink, and a manufacturing method thereof.

1 illustrates a method for measuring battery resistance of graphite powder.

2 shows a method for calculating the electrical resistance of graphite powder.

3 shows a cured sheet with grooves on both sides.

4 shows a measuring method of contact resistance of a cured product.

In view of such a situation, the present inventors made a carbon-based filler and a curable resin composition as the main raw materials, and the cured product has excellent conductivity and has been intensively studied for the development of a conductive curable resin composition having excellent heat dissipation properties. In order to develop a conductive curable resin composition and an uncured sheet prepared from the composition by adding an elastomer of the present invention, filling a carbon-based filler to a large content, and excellent in formability and capable of forming a uniform sheet in an uncured state. Succeeded. In addition, a combination of a specific carbon material containing boron and the curable resin composition invented and completed a thin, highly accurate fuel cell separator, a battery component, an electrode or a heat sink, and a manufacturing method thereof.

In other words, the present invention for achieving the above object is a conductive curable resin composition according to the following [1] to [20], an uncured sheet made of them, a fuel cell separator, a battery component, an electrode or a heat sink using the same and its manufacture It is about a method.

[1] A curable resin composition containing an elastomer having a Mooney viscosity (ML _{1 + 4} (100 ° C.)) of 25 or more at a ratio of 2-80 wt% and (B) a carbon material, (A) component to (B) component Conductive curable resin composition characterized in that it comprises so that the weight ratio of 70-5: 30-95.

[2] The curable resin composition according to the above [1], wherein (A1) a Mooney viscosity (ML _{1 + 4} (100 ° C.)) has an elastomer of 80-2 wt% and (A2) radical reactive resin 20-98 wt% and (A3) organic peroxide, the total amount of component (A) and (B) is 100wt%, and component (A3) is 0.2- with respect to 100 parts by weight of (A1 + A2) It is 10 weight part, electroconductive curable resin composition.

[3] The elastomer of component (A1), wherein the elastomer of component (A1) is acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer copolymer rubber, ethylene A conductive curable resin composition characterized in that it is one or two or more combinations selected from the group consisting of butadiene rubber, fluorine-containing rubber, isoprene rubber, silicone-rubber, acrylic rubber and butadiene rubber.

[4] The elastomer of component (A1), wherein the elastomer of component (A1) is acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer copolymer, and Conductive curable resin composition, characterized in that one or two or more combinations selected from the group consisting of butadiene rubber.

[5] The carbon material according to any of the above [1] to [4], wherein the carbon material of component (B) is graphite powder, artificial graphite powder, natural graphite powder, expanded graphite powder, carbon fiber, or fiber diameter of 0.05-10 µm. One or two or more combinations selected from the group consisting of carbonaceous carbon fibers having a fiber length of 1-500 μm, carbon nanotubes having a fiber diameter of 0.5-100 nm, and fiber lengths of 0.01-10 μm, and carbon black. Electroconductive curable resin composition characterized by the above-mentioned.

[6] The conductive curable resin composition according to the above [5], wherein the graphite powder has an average particle diameter of 0.1 to 150 µm and a lattice spacing (Co value) of 6.745 kPa or less.

[7] The component (B) according to any one of the above [1] to [6], wherein the component (B) is pressurized so that the bulk density of the carbon material of the component (B) is 1.5 g / cm 3. The powder electrical specific resistance of a carbon material is 0.07 Pacm or less, The electrically conductive curable resin composition characterized by the above-mentioned.

[8] The conductive curable resin composition according to any one of [1] to [7], wherein the carbon material of the component (B) contains 0.05-10 wt% of boron.

[9] The conductive curable resin composition according to any one of the above [1] to [8], which is used for sheet molding.

[10] An uncured sheet, wherein the conductive curable resin composition according to any one of the above [1] to [9] is molded into an uncured state by using one type of molding machine such as an extruder, a roller, and a calender. Manufacturing method.

[11] An uncured sheet produced by the method of [10].

[12] The uncured sheet according to the above [10], wherein the thickness is 0.5-3 mm and the width is 20-3000 mm.

[13] A method for producing a grooved cured sheet, wherein the uncured sheet according to the above [11] or [12] is cut or punched, the sheet is fed into a mold and thermoset with a compression molding machine.

[14] A fuel cell separator manufactured by the method as described in [13] above using a die having grooves on one side or both sides.

[15] A fuel cell separator obtained by curing the uncured sheet according to the above [11] or [12].

[16] The conductive curable resin composition according to any one of the above [1] to [9] or the uncured sheet according to the above [11] to [12] is supplied into a mold having grooves on both sides thereof, and then cured by a compression molding machine. A fuel cell separator comprising a cured product obtained by the above method, having a volume resistivity of 2 × 10 ^-2 Ωcm or less, a contact resistance of 2 × 10 ^-2 Ωcm ² or less, a thermal conductivity of 1.0 W / mK or more, and a ventilation rate of 1 A fuel cell separator, wherein the fuel cell separator is at most 10 ⁶ cm 2 / sec or less and contains 0.1 ppm or more of boron.

[17] A curable resin composition comprising an elastomer in a ratio of 2-80 wt% and (B) a carbon material, based on the weight of the curable resin composition (A), from (A) component to (B) component. A fuel cell separator, a battery component, an electrode or a heat sink, characterized in that it is a grooved conductive curable resin sheet containing a weight ratio of 70-5: 30-95.

[18] The above-mentioned [17], wherein the elastomer of component (A) is acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer copolymer rubber, ethylene A fuel cell separator, battery component, electrode or heat sink, characterized in that it is one or two or more combinations selected from the group consisting of butadiene rubber, fluorine-containing rubber, isoprene rubber, silicone-rubber, acrylic rubber, butadiene rubber.

[19] The fuel cell separator, battery component, electrode or the above-mentioned [17] or [18], wherein the component (A) contains 80-2 wt% of an elastomer and 20-98 wt% of a radical reactive resin. Heat sink.

[20] The material resistivity according to any one of [17] to [19], wherein the volume resistivity is 2 × 10 ⁻² Pacm or less, the contact resistance is 2 × 10 ⁻² Pacm ² or less, and the thermal conductivity is 1.0 W / m · K or more. And a ventilation rate is 1 × 10 ⁻⁶ cm 2 / sec or less, and contains 0.1 ppm or more of boron.

Best Embodiments of the Invention

The present invention will be described in more detail.

The elastomer (A1) in the curable resin composition of component (A) according to the present invention may be selected from the group consisting of acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer copolymer, Ethylene-butadiene rubber, fluorine-containing rubber, isoprene rubber, silicone-rubber, acrylic rubber, butadiene rubber, high styrene rubber, chloroprene rubber, urethane rubber, polyether-based special rubber, tetrafluoroethylene-propylene rubber, epichlorohi It is a combination of one or two or more selected from rubber, norbornane and butyl rubbers.

Among them, acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer copolymer rubber, ethylene-butadiene rubber, butadiene rubber, fluorine-containing rubber, high styrene Rubbers, polyether-based specialty rubbers and epichlorohydrin rubbers are preferred in view of durability, water resistance and workability, and include acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene Particular preference is given to diene terpolymer copolymer rubber and butadiene rubber.

The elastomer (A1) contained in the curable resin composition of component (A) according to the present invention has a Mooney viscosity (ML _{1 + 4} (100 ° C.)) of 25 or more, preferably 40 or more, more preferably 50 or more. When the Mooney viscosity (ML _{1 + 4} (100 ° C.)) is 25 or less, the loadability of the carbon material filler deteriorates, and when the carbon material filler is filled with a large amount of content, a uniform uncured sheet is continuously formed. It's hard to do Mooney viscosity can be measured using Mooney viscosity meter AM-1 (made by Tokyo Seiki Seisakusho, Ltd.) based on JISK6300. In ML _{1 + 4} (100 ° C.), M is Mooney viscosity, L refers to L rotary type, _{1 + 4} refers to 1 minute of preheating and 4 minutes of rotor operation, and (100 ° C) refers to the test temperature of 100 ° C. Refers to.

The radically reactive resin (A2) contained in the curable resin composition of component (A) according to the present invention contains a vinyl group or an allyl group at the terminal of the molecule, or contains a carbon-carbon unsaturated double bond or a primary carbon alkyl chain in the main chain. It is a resin or the resin composition containing the said resin. For example, one or more types of compositions selected from unsaturated polyester resins, vinyl ester resins, allyl ester resins, urethane acrylate resins, alkyd resins, diallyl phthalate resins and 1,2-polybutadiene resins may be mentioned.

In the field which requires heat resistance, acid resistance, etc., resin which has a ring structure like homocyclic or heterocyclic ring as molecular skeleton is preferable. For example, containing resins such as bisphenol-containing unsaturated polyester or vinyl ester resins, novolak-type vinyl ester resins, allyl ester resins and diallyl phthalate resins can improve heat resistance, chemical resistance, and hot water resistance. Preferred at

1,2-polybutadiene resins are preferred in terms of heat resistance, chemical resistance and hot water resistance, since they do not contain a double bond in the main chain.

According to the present invention, the component to be used as the curable resin composition of component (A) further contains a radical reactive monomer containing an unsaturated double bond such as vinyl or allyl group, in addition to the components (A1) and (A2), It may be added for the purpose of adjusting the viscosity, improving the crosslinking density, adding a function, and the like. Examples thereof include unsaturated fatty acid esters, aromatic vinyl compounds, vinyl esters of saturated fatty acids and aromatic carboxylic acids, their derivatives and crosslinkable polyfunctional monomers.

Unsaturated fatty acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, Alkyl (meth) acrylates such as octadecyl (meth) acrylate, cyclohexyl (meth) acrylate and methylcyclohexyl (meth) acrylate; phenyl (meth) acrylate, benzyl (meth) acrylate, 1-naph With methyl (meth) acrylate, fluorophenyl (meth) acrylate, chlorophenyl (meth) acrylate, cyanophenyl (meth) acrylate, methoxyphenyl (meth) acrylate and biphenyl (meth) acrylate Acrylic acid aromatic esters such as; haloalkyl (meth) acrylates such as fluoromethyl (meth) acrylate and chloromethyl (meth) acrylate; Glycidyl (meth) acrylate, alkylamino (meth) acrylate, α-cyano acrylic acid ester and the like.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene, and vinyltoluene.

Saturated fatty acids or aromatic carboxylic acid vinyl esters and derivatives thereof include vinyl acetate, vinyl propionate and vinyl benzoate.

As crosslinkable polyfunctional monomers, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di ( Meta) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,5-pentadiol di (meth) acrylate, 1,6-hexadiol Di (meth) acrylate, neopentylglycol di (meth) acrylate, oligo ester di (meth) acrylate, polybutadiene di (meth) acrylate, 2,2-bis (4- (meth) acryloyl Di (meth) acrylates such as oxyphenyl) propane and 2,2-bis (4-w- (meth) acryloyloxypyriethoxy) phenyl) propane; Diallyl phthalate, diallyl isophthalate, dimethallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylate, diallyl 1,5-naphthalenedicarboxylate, diallyl 1,4- Aromatic diallyl carboxylates such as xylenedicarboxylate and diallyl 4,4'-diphenyldicarboxylate; Difunctional crosslinkable monomers such as diallyl cyclohexanedicarboxylate and divinylbenzene; Trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tri (meth) allyl isocyanurate, tri (meth) allyl cyanurate, tri Trifunctional crosslinkable monomers such as allyl trimellitate and diallyl chlordate; And tetrafunctional crosslinkable monomers such as pentaerythritol tetra (meth) acrylate.

Among these, addition of a crosslinkable polyfunctional monomer is preferable in order to improve heat resistance and hot water resistance.

As the organic peroxide (A3) used in the curable resin composition of the component (A) according to the present invention, known components such as dialkyl peroxide, acyl peroxide, hydroperoxide, ketone peroxide, and peroxy ester can be used. have. Specific examples include benzoyl peroxide, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanate, 1,1 -Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (4,4-dibutylperoxycyclo Hexyl) propane, t-hexylperoxy-2-ethylhexanate, t-butylperoxy-2-ethyl hexanate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2, 5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxy benzoate, t-butylcumyl peroxide, p-methane hydroperoxide, t-butyl hydroperoxide, cumene hydroperoxide, Dicumyl peroxide, di-t-butylperoxide, 2,5-dimethyl-2,5-dibutylperoxyhexine-3, and the like.

Among these, those having a decomposition temperature of 90 ° C to 190 ° C and an activation energy of 30 Kcal / mol or more are preferable in terms of strength and durability as well as the production molding cycle. Preferred embodiments include 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2 , 5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, t-butylcumyl peroxide, p-methane hydro Loperoxide, t-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, di-t-butyl peroxide and 2,5-dimethyl-2,5-dibutylperoxyhexine-3.

The weight ratio of the elastomer (A1) and the radical reactive resin (A2) in the curable resin composition is 80-2 wt% of the elastomer and 20-98 wt% of the radical reactive resin (A1 + A2 = 100 wt%). If the amount of elastomer exceeds 80 wt%, the conductivity of the cured product is lowered, while if it is less than 2 wt%, sheet formability is deteriorated. More preferably, the proportion of elastomer is 70-5 wt% and the ratio of radical reactive resin is 30-95 wt%. More preferably, the elastomer ratio is 60-10 wt% and the radical reactive resin ratio is 40-90 wt%.

The organic peroxide (A3) contained in the curable resin composition is added at 0.2-10 parts by weight based on 100 parts by weight of (elastomer (A1) + radically reactive resin (A2)). More preferably 0.5-8 parts by weight, even more preferably 0.8-6 parts by weight. If the amount of the organic peroxide (A3) exceeds 10 parts by weight, the gas generated due to the decomposition of the organic peroxide increases, often causing a decrease in the airtightness of the product. Moreover, if it is less than 0.2 weight part, since the crosslinking density of a product will become low, strength may fall, and durability may also fall also.

Preferably, the carbon material of component (B) according to the present invention is graphite powder, artificial graphite powder, natural graphite powder, expanded graphite powder, carbon fiber, fiber diameter of 0.05-10 m, fiber length of 1-500 m It is a mixture made of one or two or more kinds selected from the group consisting of a vapor-phase carbon fiber, a fiber diameter of 0.5-100 nm and a fiber length of 0.01-10 μm and carbon nanotubes and carbon black.

The graphite powder has an average particle diameter of 0.1-150 µm, more preferably 5-80 µm, and a graphite fine powder having a lattice spacing (Co value) of 6.745 mm 3 or less. The graphite powder preferably contains boron.

The boron-containing graphite fine powder having an average particle diameter of 5-80 μm and a lattice spacing (Co value) of 6.745 kPa or less is used to improve the conductivity of graphite powder and the loadability-to-resin of the graphite powder. Can be obtained by addition during graphitization and graphitization.

When boron is not added, the graphitization degree (crystallization degree) to graphitize becomes low, the lattice spacing (hereinafter referred to as "Co value") becomes large, and sufficient highly conductive graphite powder cannot be obtained.

The boron-containing form is not particularly limited as long as the boron and / or boron compound is mixed in the graphite, but it is more preferable that boron is present between the layers of the graphite crystal, or a part of the carbon atoms forming the graphite crystal is substituted with the boron atom. . When some of the carbon atoms are replaced with boron atoms, the bond between the boron atom and the carbon atom may be in any form such as a covalent bond or an ionic bond.

In order to obtain graphite powder, coke is usually prepared first. As the raw material of the coke, petroleum pitch, coal pitch may be used. This raw material is carbonized to produce coke.

In general, the graphitized powder from the coke is a method of pulverizing the coke after graphitization, a method of graphitizing and pulverizing the coke itself, or by adding a binder to the coke, forming and firing the fired product (here, Both of the fired products are referred to as coke), and then pulverized after graphitizing. According to the invention, preference is given to using a method of graphitizing the coke after grinding. Since the raw material coke should be as low as possible in the degree of crystal development, it is preferable to heat-process the raw material coke to the temperature of 2000 degrees C or less, Preferably it is 1200 degrees C or less.

Graphitization of the coke powder not only promotes crystallization but, at the same time, the surface area of the particles is reduced, and thus found to be preferable in this respect.

For example, the specific surface area of the coke powder having an average particle diameter of 10 μm obtained by grinding the coke is about 14 m 2 / g, but when it is graphitized at 2800 ° C. or more, the specific surface area decreases to 2-3 m 2 / g. However, when pulverization is carried out after graphitization, depending on this particle diameter, this value is at least 5 m 2 / g, in some cases at least 10 m 2 / g. In comparison with this. As a method of graphitization after grinding, by rearranging carbon atoms during graphitization and volatilizing a portion of the surface at high temperatures, the surface will be clean or smoothed and the specific surface area will be low.

For pulverizing coke, high-speed rotary mills (hammer mills, pin mills or cage mills), or various ball mills (tumbling mills, vibratory mills or planetary mills), stirring mills (bead mills, attritors, flow mills or Annular mill) and the like. In addition, suitable conditions can be selected for screen mills, turbo mills, super micron mills, and jet mills. The coke is pulverized using the pulverizer, the pulverization conditions are selected and, if necessary, the powder is classified, and the average particle diameter is preferably in the range of 0.1 to 150 mu m. More preferably, the particle diameter substantially eliminates particle diameters of less than 0.1 μm and / or more than 150 μm and the particles are made 5 wt% or less, preferably 1 wt% or less.

Preferably, the graphite powder of the present invention contains boron, and the average particle diameter of the granular form of the graphite powder is preferably 0.1 -150 µm, more preferably 1-100 µm, even more preferably 5-80 µm. to be. The particle diameter was measured by laser diffraction scattering method. Specifically, 50 mg of the sample was weighed, added to 50 ml of distilled water, 0.2 ml of a 2% triton (surfactant) aqueous solution was further added, and the mixture was ultrasonically dispersed for 3 minutes, and then the microtrack HRA of Nikkiso Corp. It was measured with a (Microtrack HRA) device.

The method of classifying the coke powder can be any separable material, for example starch or forced vortex centrifugal classifier (micron separator, turboflex, turbo classifier or super separator) or inertial classifier (improved virtual impactor or Air classifiers such as elbow jets) can be used. Wet sedimentation or centrifugation may also be used.

In order to obtain the graphite powder according to the present invention, before the graphitization treatment, elemental B, H ₃ BO _3, B ₂ O ₃ , B ₄ C _, BN and the like are added to the powder, such as coke, as a boron source, and the mixture is thoroughly mixed. Make up. If the mixture of the boron compound and the carbon material is nonuniform, not only the graphite powder becomes nonuniform, but also the possibility of sintering the graphite powder during graphitization increases. In order to obtain a uniform mixture, the boron source is preferably prepared as a powder having a particle size of 50 µm or less, preferably 20 µm or less, and then mixed with powder such as coke.

For powders such as coke powder containing a boron source, the graphitization temperature is preferably high, but due to limitations in the apparatus and the like, the range of 2500-3200 ° C is preferred. As the graphitization method, a method of using an arch furnace (Atchison Furnace), in which a powder is charged into a graphite crack and directly charged, a method of heating the powder with a graphite heating element, or the like can be used.

Preferably, the graphite powder of the present invention has high crystallinity, and the Co value of the graphite structure in which the stacked hexagonal reticular layers are stacked is preferably 6.745 kPa or less, more preferably 6.730 kPa or less. More preferably, it is 6.720 GPa or less. In order to increase the crystallization of the graphite powder, the electrical ratio resistance of the cured product is lowered.

Expanded graphite powder is immersed in a highly oxidizing solution such as a mixture of concentrated sulfuric acid and nitric acid, or a mixture of concentrated sulfuric acid and hydrogen peroxide, by, for example, graphite having a highly crystalline structure such as natural graphite or pyrolytic graphite. And a powder obtained by generating a graphite interlayer compound, washing with water, and rapidly heating to expand the C-axis direction of the graphite crystal, or a powder obtained by rolling the powder into a sheet once and then grinding it.

The carbon fiber may be a pitch-based fiber made from heavy oil, by-product oil, cortar, or the like, or a PAN-based fiber made from polyacrylonitrile.

Vapor phase carbon fibers can be obtained, for example, by pyrolysis reaction at a temperature of 800-1300 ° C. with hydrogen gas in the presence of a transition metal catalyst such as ferrocene as a raw material of an organic compound such as benzene, toluene or natural gas. After that, it is preferable to graphitize at about 2500-3200 ° C. More preferably, the graphitization treatment is performed at about 2500-3200 ° C. with a graphitization catalyst such as boron, boron carbide, beryllium, aluminum or silicon.

According to the invention, it is preferred to use vapor phase carbon fibers having a fiber diameter of 0.05-10 μm and a fiber length of 1-500 μm, more preferably a fiber diameter of 0.1-5 μm and a fiber length of 5-50 μm. More preferably, it is preferable to use those having a fiber diameter of 0.1-0.5 μm and a fiber length of 10-20 μm.

Carbon nanotubes have recently attracted industrial attention not only for their mechanical strength but also for their field emission and hydrogen occlusion functions, and their magnetic functions have also begun to attract attention. Such carbon nanotubes are well known as graphite whiskers, filamentous carbon, graphite fibers, ultrafine carbon tubes, carbon tubes, carbon fibers, carbon microtubes, and carbon nanofibers. Carbon nanotubes include single layer carbon nanotubes containing only a single graphite film forming a tube, and multilayer carbon nanotubes including several graphite films forming a tube. Although any of these can be used in the present invention, it is preferable to obtain a cured product having high electrical conductivity and mechanical strength than using single-walled carbon nanotubes.

Carbon nanotubes can be produced, for example, by the arc discharge method, the laser evaporation method or the pyrolysis method described in "Carbon Nanotube Basics" published by Corona Co., Ltd. (P23-P57, issued in 1998). It can be purified by centrifugation, ultrafiltration or oxidation. More preferably, high temperature heating is performed at about 2500-3200 ° C. under an inert gas atmosphere to remove impurities. More preferred is a high temperature treatment at 2500-3200 ° C. under an inert gas atmosphere with graphite catalysts such as boron, boron carbide, beryllium, aluminum, silicon and the like.

In the present invention, it is preferable to use carbon nanotubes having a fiber diameter of 0.5-100 nm and a fiber length of 0.01-10 μm, more preferably a fiber diameter of 1-10 nm, and a fiber length of 0.05-5 μm, even more. Preferably the fiber diameter is 1-5 nm and the fiber length is 0.1-3 μm.

The fiber size and fiber length of the vapor phase carbon fibers and carbon nanotubes according to the present invention can be measured by electron microscopy.

As carbon black, Ketjen black or acetylene black obtained by incomplete combustion of natural gas or pyrolysis of acetylene, thermal carbon obtained by pyrolysis of furnace carbon and natural gas obtained by incomplete combustion of hydrocarbon oil or natural gas. Carbon may be mentioned.

The carbon material of the component (B) according to the present invention preferably has a low powder electrical ratio resistance in a direction perpendicular to the pressing direction when the bulk density is 1.5 g / cm 3, preferably 0.07 cm 3 or less, and 0.01 mm or less. More preferred. When the electrical resistivity of the carbon material exceeds 0.07 kcm, the conductivity of the cured product obtained by curing the composition containing the curable resin also becomes low, and a desired cured product cannot be obtained.

The measuring method of the electrical resistivity of the graphite powder is shown in FIGS. 1 and 2. In Fig. 1, 1 and 1 'are the positive and negative electrodes made of copper, respectively, 2 is a compression rod made of resin, 3 is a pedestal, 4 is a side frame, and both Made of resin, 5 is a graphite powder sample, 6 is a lower end of the sample, and is a voltage measuring terminal provided in the center portion in the vertical direction with respect to the ground.

Using the four-terminal method shown in Fig. 1 and Fig. 2, the electrical resistivity of the sample was measured by the following method. The sample is compressed with a compression rod 2. A current I flows from the positive electrode 1 to the negative electrode 1 '. Measure the voltage (V) between terminals (6). Here, the voltage used is a value measured when the sample is pressed to a bulk density of 1.5 g / cm 3 by a compression rod. If the electrical resistivity (terminal) of the sample is R (Ω), then R = V / I. From this, the electrical resistivity can be determined by ρ = R · S / L (ρ: electrical resistivity, S = cross section area (cm 2) perpendicular to the charging direction of the sample, that is, the pressing direction, and L is the terminal 6. distance between (cm)). In the case of the actual measurement, the sample has a cross-sectional area of about 1 cm in the vertical direction, 0.5-1 cm in length (height), 4 cm in the energizing direction, and 1 cm in distance between terminals.

Boron contained in the carbon material of component (B) according to the present invention is preferably present at 0.05-10 wt% in the carbon material. If the boron content is less than 0.05 wt%, the graphite powder of the desired high conductivity cannot be obtained. If the boron content exceeds 10 wt%, the effect of improving the conductivity of the carbon material cannot be expected, which is not preferable.

As the boron addition method, the boron-containing graphite fine powder of the present invention may be used alone, or may be added by mixing with another carbon material. Alternatively, the element B or B ₄ C, BN, B ₂ O as a source of boron in a product such as artificial graphite, natural graphite, carbon fiber, vapor-phase carbon fiber (VGCF), carbon nanotubes (CNT), or mixtures thereof. _3, such as the addition of H ₃ BO ₃ and, may contain a boron by graphitization treatment at about 2500-3200 ℃.

The curable resin composition (A) and the carbon material (B) of the present invention have a weight ratio of 70-5: 30-95. When the addition amount of (A) component exceeds 70 wt% and the amount of (B) carbon material is less than 30 wt%, the electroconductivity of hardened | cured material will reduce. The ratio of the component (A) and the component (B) is more preferably 45-5: 55-95, even more preferably 20-10: 80-90.

The conductive curable resin composition of the present invention is a glass fiber, an inorganic fiber filler, an organic fiber, an ultraviolet stabilizer, an antioxidant, an antifoaming agent, a leveling agent for the purpose of improving hardness, strength, conductivity, moldability, durability, weather resistance, water resistance, and the like. Additives such as mold release agents, lubricants, water repellents, thickeners, low shrinkage agents, hydrophilic enhancers, crosslinking aids and the like can also be added.

In order to obtain a conductive curable resin composition according to the present invention, each of the above components is generally used in resin fields such as rollers, extruders, kneaders, Banbury mixers, Henschel mixers, planetary mixers, and the like. It is preferable to use a mixer or kneader to mix the mixture evenly, while maintaining the temperature at a temperature at which curing does not start. When adding an organic peroxide, it is advisable to mix all the other components uniformly first and then add the organic peroxide last and mix.

The obtained electroconductive curable resin composition is once shape | molded once by the sheet | seat of predetermined thickness and width using the extruder, a roller, a calender, etc. at the temperature at which hardening does not start using an extruder, a roller, a calender, etc. in order to obtain the fuel cell separator with good thickness precision. For example, in the case of using an extruder, the conductive curable resin composition in powder or lump form is put into a sheet molding die-equipped extruder maintained at a temperature of 60-100 ° C., and then molded by a conveyor or the like. Put it out. In order to make the thickness precision more excellent, it is preferable to mold in an extruder and then calender with a roll or a calender. It is desirable to extrude under vacuum to remove voids or air in the sheet. When using a roll, to form a sheet, a powdered or lumped conductive curable resin composition is inserted between two rolls maintained at a temperature of 20-100 ° C, rotated at the same speed, and then loaded by a conveyor or the like. In order to shape | mold excellent thickness precision, it is preferable to calendar with a roll or a calendar after sheet formation.

The use of the conductive curable resin product obtained from the conductive curable resin composition of the present invention is not particularly limited, but was developed for the purpose of manufacturing fuel cell separators, battery parts, electrodes, and heat sinks, and thus, as fuel separators, battery parts, electrodes, and heat sinks. Very suitable.

In order to manufacture fuel cell separators, battery components, electrodes or heat sinks from the sheet obtained by the above method, after cutting or punching the sheet to the required size, one sheet or two or more sheets are grooved on one side or both sides. And heat-cured by a compression molding machine to obtain a fuel cell separator, a battery component, an electrode, and a heat sink. In order to obtain a defect free product, it is desirable to vacuum the inside of the cavity during curing. After curing, in order to correct the warping of the product, it is preferable to pressurize to 3 MPa or more between the pressure plates controlled at 10-50 ° C. to cool.

As conditions for hardening, it is important to select and select the optimum temperature according to the kind of composition. For example, in the temperature range of 120-200 ° C. for 30-1200 seconds, the conditions can be appropriately determined. After curing, after curing for 10-600 minutes in the temperature range of 150-200 ℃ to obtain a complete cured body. Post-curing can pressurize to 5 Mpa or more, and can suppress the distortion of a product.

It is preferable that the fuel cell separator, battery component, electrode, or heat sink of the present invention have the following characteristics. Specifically, the volume resistivity is preferably 2 × 10 ⁻² Pa or less, more preferably 8 × 10 ⁻³ Pa or less, and particularly preferably 5 × 10 ⁻³ Pa or less for fuel cell separator applications. The contact resistance is preferably 2 × 10 ^-2 cm ³ or less, more preferably 1 × 10 ^-2 cm ² or less, particularly preferably 7 × 10 ^-3 cm ² .

As for thermal conductivity, 1.0 W / m * K or more is preferable, More preferably, it is 4.0 W / m * K or more, Especially 10 W / m * K or more is preferable. The air permeability, which is an important characteristic of the fuel cell separator, is preferably 1 × 10 ⁻⁶ cm 2 / sec or less, more preferably 1 × 10 ⁻⁸ cm 2 / sec or less, particularly preferably 1 × 10 ⁻⁹ cm 2 / sec.

3 shows a specific example of a cured sheet with grooves on both sides. The use of such a hardened sheet with grooves on both sides is known as the structure of the fuel cell, and the description thereof is not considered necessary (see, for example, Japanese Laid-Open Patent Publication No. 58-53167).

Since the conductive curable resin composition of the present invention can form a continuous sheet even when the carbon material is high-filled, it is optimal for the use of composite materials in fields requiring thickness precision such as fuel cell separators, battery components, electrodes or heat sinks. . The cured product obtained therefrom can be reproduced without limiting the conductivity and thermal conductivity of graphite, and a high-performance one is obtained in that it is excellent in heat resistance, corrosion resistance and molding accuracy. Therefore, it is useful for each use, such as various parts, such as an electronic field, an electric, a machine, a vehicle, etc., and especially suitable as a material for fuel cell separators, battery components, electrodes, or a heat sink.

Although an Example demonstrates this invention further more concretely, this invention is not limited to these Examples.

The materials used are as follows.

(A) component (curable resin composition)

A1: elastomer

NBR1 (acrylonitrile-butadiene rubber; Nipol DN003 from Nihon Zeon, Mooney viscosity (ML _{1 + 4} (100 ° C.): 78)

NBR2 (acrylonitrile-butadiene rubber; Nipol 1312 from Nihon Zeon, Mooney viscosity (ML _{1 + 4} (100 ° C): cannot be measured because it is in liquid form)

EPDM (Ethylene-propylene-diene rubber; EP25 by Nihon Synthetic Rubber, Mooney Viscosity (ML _{1 + 4} (100 ° C): 90)

SBR (Styrene-Butadiene Rubber; SL574, Nihon Synthetic Rubber, Mooney Viscosity (ML _{1 + 4} (100 ° C): 64)

A2: radical reactive resin

ALE (allyl ester resin; AA101 by Showa Denko K.K)

VE1 (Vinyl ester resin; Sample containing 5 wt% phenol novolac diallyl phthalate from Showa Highpolymer Co. Ltd .; Viscosity: 2.1 (Pasec, 80 ° C)

VE2 (vinyl ester resin; H-600 from Showa Highpolymer Co. Ltd)

UP (unsaturated polyester resin: Nihon Upica company Upica 5836)

A3: organic peroxide

DCP (Dicumyl Peroxide; Percumyl D from Nihon Oils and Fats)

(B) Component (Carbon Material)

B1: Boron-containing graphite fine powder was obtained by the following method.

LPC-S from Nippon Steel Chemical Co., Ltd. (naturally calcined) non-coarse coke (hereinafter referred to as "coke A") is a fine grinding machine (Hosokawa Micron Co., Ltd.) of 2-3 mm size Coarsely crushed into. The coarse ground product was pulverized with a jet mill (IDS2UR, Nihon Pneumatic Co.LTD). It was then sieved to adjust to the desired particle size. Particles of 5 mu m or less were removed by air flow classification using a turbo classifier (TC15N, manufactured by Nissin Engineering Co. Ltd.). After adding 0.6 kg of boron carbide (B ₄ C) to 14.4 kg of the adjusted finely ground product, the mixture was mixed for 5 minutes at 800 rpm using a Henschel mixer. The mixture was then placed in a 40 cm inside diameter, 40 liter volume-covered graphite croque, and the croque placed in a graphitization furnace using a graphite heater and graphitized at a temperature of 2900 ° C. After cooling, the fine powder was taken out and 14 kg of fine powders were obtained. The average particle diameter of the obtained graphite fine powder was 20.5 micrometers, lattice spacing (Co value) was 6.716 GPa, and B content was 1.3 wt%.

B ₂ : Graphite fine powder containing no boron was obtained by the following method.

Coke A was coarsely ground to a size of 2-3 mm with a mill. The coarse powder was pulverized with a jet mill. It was then sieved to adjust to the desired particle size. Particles of 5 mu m or less were removed by air flow classification using a turbo classifier. Thereafter, the powder was placed in a cover-attached graphite crack having a diameter of 40 cm and a volume of 40 liters, and the croque was placed in a graphitization furnace using a graphite heater and graphitized at a temperature of 2900 ° C. After cooling, the fine powder was taken out and graphite fine powder was obtained. The average particle diameter of the graphite fine powder was 20.5 µm, the lattice spacing (Co value) was 6.758 mm 3, and the B content was 0 wt%.

UFG: artificial graphite; Show Denko K.K's UFG30

EXP: expanded graphite; Nihon Graphite Industry Company EXP-50EL

VGCF: vapor phase carbon fiber; Show Denko K.K VGCF-G (fiber diameter: 0.1-0.3 μm, fiber length: 10-50 μm)

CNT: carbon nanotubes were obtained by the following method.

In a graphite rod 6 mm in diameter and 50 mm in length, a hole having a diameter of 3 mm and a depth of 30 mm was drilled along the central axis from the tip, and rhodium (Rh): platinum (Pt): graphite (C) in the hole was weight ratio 1: 1: 1. Filled with a mixed powder of to form a positive electrode. Meanwhile, a negative electrode having a diameter of 13 mm and a length of 30 mm made of graphite having 99.98% purity was produced. These electrodes were arranged facing each other in the reaction vessel, and brought into contact with a DC power source. The inner wall of the reaction vessel was replaced with 99.9% helium gas to perform direct current arc discharge. The soot (chamber soot) attached to the inner wall of the reaction vessel and the soot accumulated on the cathode (cathode soot) were recovered. Pressure and current conditions in the reaction vessel were 600 Torr and 70 A. During the reaction, the gap between the anode and the cathode was kept at 1-2 mm.

The collected soot was added to a mixed solvent of water and ethanol 1: 1, and ultrasonically dispersed, the dispersion was recovered, and the solvent was removed by a rotary evaporator. The sample was ultrasonically dispersed in a 0.1% aqueous solution of benzalkonium chloride as a cationic surfactant, centrifuged at 5000 rpm for 30 minutes, and the dispersion was recovered. The dispersion was then purified by heat treatment at 350 ° C. for 5 hours in air to obtain carbon nanotubes having a fiber diameter of 1-10 nm and a fiber length of 0.05-5 μm.

Physical properties of the cured product were measured by the following method.

Volumetric resistivity:

It measured by the 4-probe method according to JISK7194.

Contact resistance:

Using the apparatus shown in FIG. 4, the test piece 21 (20 mm × 20 mm × 2 mm) and the carbon plate 22 (1.5 × 10 ⁻³ cm cm, 20 mm × 20 mm × 1 mm) were brought into contact with each other, and the copper plate 23 was contacted. Was inserted into a load of 98 N. After flowing a constant current of 1 A in the penetrating direction, the terminal 24 was brought into contact with the interface between the test piece 21 and the carbon plate 22 to measure the voltage, and the resistance value was calculated. The cross-sectional area in contact with the value was integrated to obtain contact resistance.

Bending Strength, Bending Modulus, and Bending Strain:

According to JIS K6911, the test piece was measured by the 3-point bending strength test method on the conditions of 64 mm of span spacing, and 2 mm / min of bending speed. The test piece size was 100 x 10 x 1.5 mm.

Thermal conductivity:

By the laser flash method (t _1/2 method, using Rigaku Denki's LF / TCM FA8510B Laser Flash Thermal Constant Measuring Apparatus), the test piece (φ 10 mm, thickness: 1.7 mm) was subjected to a temperature of 80 ° C. in a vacuum and a ruby laser light ( It measured under the conditions of excitation voltage: 2.5kV).

Gas Permeability:

According to the method A of JISK7126, it measured using He gas at 23 degreeC.

Sheet formability:

Using 10-inch twin rolls, the curable conductive resin composition was introduced into a sheet under a roll temperature of 60 ° C., a roll gap width of 2 mm, and a rotation speed of 15 rpm, and the moldability and appearance were evaluated.

Boron content in carbon materials:

It was measured using an inductively coupled plasma gravimetric apparatus (ICP-MS) (SPQ9000, Seico Instrument Inc.).

Facet precision:

The surface of the cured sheet was uniformly divided into 16 parts, the thickness of the sheet was measured at the center point of each part, and the average of the thicknesses was calculated.

Example 1-15 and Comparative Example 3

In the case of Example 1-15 and the comparative example 3, the pressurized kneader (capacity: 1 L) was used for 1 minute, and the elastomer component was thrown in and kneaded on condition of the temperature of 70 degreeC, and rotation speed of 40 rpm. Subsequently, the radical reactive resin and the carbon material were added and stirred for 5 minutes, and then DCP was added and kneaded for 2 minutes. The total amount of the composition was adjusted to fill 80% of the kneader capacity. After kneading, the composition was formed using a 10 inch twin roll, a sheet having a thickness of 2 mm was formed under conditions of a rapid rotation of a roll temperature of 60 ° C., a roll gap width of 2 mm and a rotation speed of 15 rpm, and a 100 × 100 × 1.5 mm plate was formed. The sheet | seat was cut out and put into the mold which can be formed, it hardened | cured for 5 minutes under the pressurization of mold temperature of 170 degreeC, and 30 MPa using the 50t compression molding machine, and the hardened | cured material was obtained.

Comparative Example 1-2

In the case of Comparative Example 1-2, the elastomer component was kneaded by using a pressure kneader (capacity: 1 L) for 1 minute under conditions of a temperature of 70 ° C and a rotational speed of 40 rpm. Next, a radical reactive resin and a carbon material were added and kneaded for 5 minutes, and then DCP was added and kneaded for 2 minutes. The total amount of the composition was adjusted to fill 80% of the kneader capacity. The kneaded product was put into a mold capable of forming a flat plate of 100 × 100 × 1.5 mm, and cured for 5 minutes under a pressurization of a mold temperature of 170 ° C. and 30 MPa using a 50t compression molding machine to obtain a cured product.

Example 16

Example 16 In the case of the composition used in Example 1, using a 10 inch twin roll, a 1.7 mm thick uncured sheet was formed under conditions of the same rotation of a roll temperature of 60 ° C., a roll gap width of 1.7 mm and a rotation speed of 15 rpm. Cut the sheet into 280 × 200 mm, 280 × 200 × 1.5 mm, and insert the cut sheet into a mold capable of forming a flat plate with 1 mm pitch grooves on both sides, and using a 500 ton crimping machine, a mold temperature of 170 ° C. It hardened | cured for 3 minutes under 60 MPa pressurization, and obtained hardened | cured material with a groove on both surfaces.

Example 17

In the case of Example 17, the composition used in Example 1 was extruded into a sheet having a thickness of 1.8 mm and a width of 70 mm using a 60Φ single screw extruder under conditions of a temperature of 60-90 ° C. and a rotation speed of 40 rpm, thereby making it uncured sheet. Was cut into 200 × 70 mm sheets, 280 × 200 × 1.5 mm sheets, 1 mm pitch grooves were cut into sheets with a mold capable of forming a flat plate on both sides in parallel, and a 500 ton crimping machine was used. It hardened | cured for 3 minutes under pressurization of 60 MPa at the metal mold temperature of 170 degreeC, and the hardened | cured material which has grooves on both surfaces was obtained.

Comparative Example 4

For Comparative Example 4, the composition used in Example 1 was pulverized using a chilled wiley mill (YOSHIDA SEISAKUSHO CO., LTD.), Having a size of 280 × 200 × 1.5 mm and having a 1 mm pitch groove. The sheets cut into the molds capable of forming flat plates on both sides were connected in parallel, and then cured for 3 minutes under a pressurization of 60 MPa at a mold temperature of 170 ° C. using a 500 ton compression molding machine to obtain a cured product having grooves on both sides. .

Comparative Example 5

For Comparative Example 5, the composition used in Example 2 was ground using a chilled Wille Mill (YOSHIDA SEISAKUSHO CO., LTD), a plate of 280 × 200 × 1.5 mm, 1 mm pitch grooves on both sides The sheets cut into molds which can be formed were connected in parallel to each other, and were put in parallel, and cured for 3 minutes under a pressure of 60 MPa at a mold temperature of 170 ° C. using a 500 ton compression molding machine to obtain a hardened body having grooves on both sides.

Example 18

In Example 18, as the separator for fuel cells, the physical properties of the cured sheet having grooves on both surfaces of Example 16 were evaluated.

Example 19

In Example 19, as the separator for fuel cells, the physical properties of the cured product having grooves on both surfaces of Example 17 were evaluated.

Comparative Example 6

In Comparative Example 6, physical properties of the cured product having grooves on both surfaces of Comparative Example 4 were evaluated as separators for fuel cells.

Comparative Example 7

In Comparative Example 7, the physical properties of the cured product having grooves on both surfaces of Comparative Example 5 were evaluated as the separator for fuel cells.

The results of Examples 18 and 19 and Comparative Examples 6 and 7 are shown in Table 4 below.

Table 1 shows that the addition of an elastomer having a high Mooney viscosity allows good sheet molding even when the carbon material is highly charged. If no elastomer was present, the carbon material was added in an amount greater than 80 wt%, and after kneading, the kneaded product produced a powdery compound. Comparative Example 3 shows that the conductivity decreases when the amount of the elastomer added is large.

Table 2 shows that when boron is contained in a carbon material, the hardened | cured material excellent in electroconductivity will be obtained.

Table 3 shows that the sheet-shaped flat plate for fuel cells having excellent surface accuracy (thickness precision) and good gas impermeability can be obtained by sheet pressure molding.

Table 4 shows that the hardened bodies with grooves on both sides obtained by sheet pressing have satisfactory performance as separators for fuel cells.

According to the present invention, by adding an elastomer having a high Mooney viscosity, a carbon material can be highly charged and a target conductive curable resin composition excellent in sheet formability was obtained. When the boron-containing carbon material is used as a filler to obtain a composition having excellent conductivity and heat dissipation, and the sheet is formed using an extruder, a roller, a calender, and the like and cured by pressure molding, gas impermeability and surface precision A thin, large area separator for fuel cells is obtained.

The electroconductive curable resin composition of this invention is excellent in electroconductivity and heat dissipation, and its hardened | cured body is extensively used for various uses and components, such as materials which cannot be achieved conventionally, such as an electric field, an electrical product, a mechanical part, a vehicle part, etc. It is applicable and especially useful as a material for separator of fuel cells, such as a solid polymer fuel cell.

Claims (20)

(A) Curable resin composition and (B) carbon material which contain the elastomer whose Mooney viscosity (ML1 _{+ 4} (100 degreeC)) is 25 or more with respect to the weight of curable resin composition (A) in the ratio of 2-80 wt%. A conductive curable resin composition comprising a component such that the weight ratio of component (A) to component (B) is 70-5: 30-95. The curable resin composition according to claim 1, wherein the curable resin composition of component (A) is an elastomer having a Mooney viscosity (ML _{1 + 4} (100 ° C.)) of 25 or more, 80-2 wt%, (A2) radical reactive resin 20-98 wt % And (A3) organic peroxide, the total amount of component (A) and component (B) is 100wt%, and component (A3) is 0.2-10 parts by weight relative to 100 parts by weight of (A1 + A2) Electroconductive curable resin composition characterized by the above-mentioned. The elastomer of claim 2, wherein the elastomer of component (A1) is acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer copolymer rubber, ethylene-butadiene rubber, A conductive curable resin composition, characterized in that it is one or two or more combinations selected from the group consisting of fluorine-containing rubber, isoprene rubber, silicone-rubber, acrylic rubber, butadiene rubber. 4. The elastomer according to claim 3, wherein the elastomer of component (A1) is composed of acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer copolymer rubber and butadiene rubber Conductive curable resin composition, characterized in that one or two or more combinations selected from the group consisting of. The gas phase method according to claim 1, wherein the carbon material of component (B) is graphite powder, artificial graphite powder, natural graphite powder, expanded graphite powder, carbon fiber, fiber diameter of 0.05-10 탆, and fiber length of 1-500 탆. A conductive curable resin composition, which is a material selected from the group consisting of carbon fibers, a fiber diameter of 0.5-100 nm, a carbon nanotube having a fiber length of 0.01-10 μm, and carbon black, or a mixture thereof. 6. The conductive curable resin composition according to claim 5, wherein the graphite powder has an average particle diameter of 0.1-150 µm and a lattice spacing (Co value) of 6.745 kPa or less. The powder electrical specific resistance of the carbon material of the component (B) in the direction perpendicular to the pressing direction when the bulk density of the carbon material of the component (B) is 1.5 g / cm 3 is 0.07 Pa or less. Electroconductive curable resin composition characterized by the above-mentioned. The conductive curable resin composition according to claim 1, wherein the carbon material of component (B) contains 0.05-10 wt% of boron. The conductive curable resin composition according to claim 1, which is used for sheet molding. A method for producing an uncured sheet, wherein the conductive curable resin composition according to any one of claims 1 to 9 is molded into an uncured state by using one kind of molding machine such as an extruder, a roller, and a calender. An uncured sheet produced by the method of claim 10. 12. Uncured sheet according to claim 11, wherein the thickness is 0.5-3 mm and the width is 20-3000 mm. A method for producing a grooved cured sheet, wherein the uncured sheet according to claim 11 is cut or punched, the sheet is fed into a mold, and thermoset with a compression molding machine. A fuel cell separator, battery component, electrode or heat sink manufactured by the method as described in claim 13 using a die having grooves on one or both sides. A fuel cell separator obtained by curing the uncured sheet according to claim 11. A fuel cell separator comprising a cured product obtained by supplying the conductive curable resin composition according to any one of claims 1 to 9 or the uncured sheet according to claim 11 to a mold having grooves on both sides, and curing the same by a compression molding machine. The volume resistivity is 2 × 10 ^-2 Ωcm or less, the contact resistance is 2 × 10 ^-2 Ωcm ² or less, the thermal conductivity is 1.0 W / m · K or more, and the air permeability is 1 × 10 ^-6 cm 2 / sec or less And 0.1 ppm or more of boron. (A) The weight ratio of the curable resin composition (A) to the curable resin composition comprising the elastomer at a ratio of 2-80 wt% and (B) the carbon material, wherein the weight ratio of the component (A) to the component (B) is 70 A fuel cell separator, a battery component, an electrode, or a heat sink, characterized in that it is a grooved conductive curable resin sheet containing a ratio of -5: 30-95. The elastomer according to claim 17, wherein the elastomer of component (A) is acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer copolymer rubber, ethylene-butadiene rubber, A fuel cell separator, battery component, electrode or heat sink characterized in that it is one or two or more combinations selected from the group consisting of fluorine-containing rubber, isoprene rubber, silicone-rubber, acrylic rubber and butadiene rubber. 18. A fuel cell separator, battery component, electrode or heat sink as claimed in claim 17, wherein component (A) comprises 80-2 wt% of elastomer and 20-98 wt% of radical reactive resin. 18. The method of claim 17, wherein the volume resistivity is 2 × 10 ^-2 Ωcm or less, the contact resistance is 2 × 10 ^-2 Ωcm ² or less, the thermal conductivity is 1.0 W / mK or more, and the ventilation rate is 1 × 10 ^-6 cm 2 It is / sec or less and contains 0.1 ppm or more of boron, The fuel cell separator characterized by the above-mentioned.