WO2005064721A1 - Composition for fuel cell separator and process for producing fuel cell separator - Google Patents

Composition for fuel cell separator and process for producing fuel cell separator Download PDF

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Publication number
WO2005064721A1
WO2005064721A1 PCT/JP2004/019031 JP2004019031W WO2005064721A1 WO 2005064721 A1 WO2005064721 A1 WO 2005064721A1 JP 2004019031 W JP2004019031 W JP 2004019031W WO 2005064721 A1 WO2005064721 A1 WO 2005064721A1
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WIPO (PCT)
Prior art keywords
epoxy resin
fuel cell
cell separator
composition
graphite
Prior art date
Application number
PCT/JP2004/019031
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French (fr)
Japanese (ja)
Inventor
Yasuhiko Watanabe
Hiroshi Ono
Takayuki Kawarada
Masaharu Takehara
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Nippon Steel Chemical Co., Ltd.
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Application filed by Nippon Steel Chemical Co., Ltd. filed Critical Nippon Steel Chemical Co., Ltd.
Priority to JP2005516579A priority Critical patent/JPWO2005064721A1/en
Publication of WO2005064721A1 publication Critical patent/WO2005064721A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0213—Gas-impermeable carbon-containing materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0221—Organic resins; Organic polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0223—Composites
    • H01M8/0226—Composites in the form of mixtures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • Composition for fuel cell separator and method for producing fuel cell separator Composition for fuel cell separator and method for producing fuel cell separator
  • the present invention is applied to a fuel cell separator composition, particularly a polymer electrolyte fuel cell separator, and comprises a graphite and resin-based separator composition, and a fuel cell separator using the composition. And a method for producing the same.
  • Fuel cells for use in automobiles, home cogeneration, and the like are receiving attention.
  • This fuel cell uses chemical energy directly as electrical energy without converting it into thermal energy, and usually refers to a battery that extracts electricity by the reaction of hydrogen and oxygen.
  • fuel cells There are several types of such fuel cells, such as phosphoric acid fuel cells, solid oxide fuel cells, and polymer electrolyte fuel cells (PEFCs).
  • a separator that is a conductive molded product is used.
  • the separator constitutes a unit cell together with electrodes and the like, and is used by stacking the unit cells.
  • the separator needs to have conductivity while isolating gas (hydrogen / oxygen).
  • Patent Document 1 JP-A-4-214072
  • Patent Document 2 JP-A-8-31231
  • Patent Document 3 JP-A-11-195422
  • Patent Document 4 JP-A-11-297338
  • Patent Document 5 JP-A-2000-40517
  • Patent Document 6 JP-A-2000-21421
  • Patent Document 7 Japanese Patent Application Laid-Open No. 2001-139696
  • Patent Document 8 Japanese Patent Application Laid-Open No. 2001-216976
  • Patent Document 9 JP-A-2002-83609
  • Patent Document 10 Japanese Patent Application Laid-Open No. 2002-201257
  • Patent Document 1 in order to obtain a carbon material suitable as a fuel cell separator having a dense and high mechanical strength and excellent conductivity, a carbon material comprising a binder and a plurality of particle sizes is used to obtain a carbon material suitable for a fuel cell separator.
  • a graphite carbon material has been proposed. However, this method requires graphitization after molding.
  • Patent Document 2 in order to obtain a carbon material suitable for a fuel cell separator having a porosity of 5% or less and a ratio of a volume resistivity in the XY direction to a volume resistivity in the Z direction of the molded body of 2 or less.
  • Patent Document 3 proposes a method in which a small amount of a binder is blended with a carbon material, pressure-formed, and then impregnated with an impregnating agent in order to reduce the amount of the binder and improve conductivity.
  • Patent Document 4 proposes a fuel cell separator having a certain range of surface roughness in order to obtain a fuel cell separator having a low contact resistance with an electrode portion.
  • Patent Document 5 proposes that artificial graphite and natural graphite be used together in order to obtain a fuel cell separator with low anisotropy.
  • Patent Document 6 proposes to use a specific graphite powder in order to obtain a fuel cell separator having a good balance of gas impermeability, thermal conductivity, conductivity, and the like.
  • Patent Documents 7 to 10 disclose a conductive epoxy resin molding material containing graphite and epoxy resin.
  • ortho-cresol novolak type epoxy resin or bisphenol type epoxy resin is used as the epoxy resin.
  • the bisphenol type epoxy resin is specifically a bisphenol A type epoxy resin.
  • Patent Document 8 discloses only a bisphenol F-type epoxy resin as an epoxy resin.
  • Patent Documents 9 and 10 disclose that as an epoxy resin, It only discloses a novolak type epoxy resin.
  • an object of the present invention is to provide a molding material that shortens the molding cycle, has excellent dimensional accuracy, and is suitable for mass production of separators in the future. Means for solving the problem
  • the inventors of the present invention have conducted intensive studies to solve such a problem, and as a result, as a resin, an epoxy resin which is solid at normal temperature but exhibits low viscosity at the time of high-temperature melting is graphite at a predetermined ratio.
  • the present inventors have found that the above problems can be solved by blending with a powder, and have completed the present invention.
  • the present invention relates to a composition containing an epoxy resin binder and graphite powder, wherein the weight ratio of the graphite powder to the epoxy resin binder is 2 to 10 times, preferably 3 to 10 times. — Compounded in a 7-fold amount, compound viscosity after kneading graphite powder and epoxy resin binder is 200-3000Pa's, and electrical resistivity is 100m ⁇ cm or less, preferably 40m ⁇ cm or less. This is a fuel cell separator composition.
  • the epoxy resin binder becomes the epoxy resin and the curing agent power
  • the epoxy resin power has a viscosity of 120 mPa's at 150 ° C, a melting point of 45 ° C to 130 ° C, and preferably 50 ° C to 130 ° C.
  • the epoxy resin power may contain one or more crystalline epoxy resins that are solid at room temperature.
  • the present invention provides a composition containing an epoxy resin binder and graphite powder, in which 2 to 10 times, preferably 3 to 7 times, the weight ratio of graphite powder to the epoxy resin binder is blended.
  • the epoxy resin binder is composed of an epoxy resin and a curing agent, and the epoxy resin is crystalline.
  • the viscosity at 150 ° C is 120 mPa's, and the melting point is 45 ° C-130 ° C.
  • Is a composition for a fuel cell separator comprising at least one kind of crystalline epoxy resin which is a solid at 50 ° C. to 130 ° C. and room temperature.
  • the crystalline epoxy resin used for the epoxy resin binder includes the following general formula (1):
  • G represents a glycidyl group
  • R represents a monovalent group
  • n represents an integer of 0-4, and
  • X represents a divalent group
  • it is an ether type epoxy resin or a thioether type epoxy resin wherein X is O or S.
  • the method for producing a fuel cell separator of the present invention comprises kneading, pulverizing, and then molding and curing the pulverized product at a temperature of 100 to 350 ° C, preferably 140 to 230 ° C.
  • the fuel cell separator of the present invention is obtained by a small manufacturing method.
  • the fuel cell separator is provided between adjacent unit cells in a fuel cell configured by stacking a plurality of unit cells, and forms a fuel gas flow path and an oxidizing gas flow path with an electrode. And has a function to separate the gas from the oxidizing gas, and a groove or the like for a gas flow path is formed.
  • the fuel cell separator manufactured by the present invention is obtained by molding and curing graphite powder and thermosetting resin into a predetermined shape. As such or as necessary, groove processing, drilling, and the like are performed. It is used as a fuel cell separator. Further, the term “fuel cell separator” is understood to include a molded product for a fuel cell separator before processing.
  • the fuel cell separator composition of the present invention contains graphite powder and an epoxy resin binder as essential components. Further, it usually contains a curing accelerator.
  • the mixing ratio of the graphite powder and the epoxy resin binder is 2 to 10 parts by weight, preferably 3 to 7 parts by weight, per 1 part by weight of the epoxy resin binder. If the amount of graphite powder is large, the fluidity during molding is inferior and a large amount of pressure is required for molding, which increases the cost of the molding machine. On the other hand, if the amount of graphite powder is small, the electrical conductivity becomes insufficient.
  • the graphite powder used in the present invention is not limited as long as it exhibits high conductivity.
  • carbonaceous materials such as mesocarbon microbeads are graphitized, and coal-based coats and petroleum-based coatas are manufactured by Kurofune.
  • natural graphite At least one of quiche graphite and expanded graphite is used.
  • one or more of coal-based and Z- or petroleum-based heavy oils are used as raw materials, and are treated at 600 ° C or lower to produce raw coats, and the raw coats are processed.
  • the ground raw material is carbonized at 700 to 1500 ° C and then graphited at 2000 ° C or higher.
  • the raw coat is formed by heat treatment, particularly by using a delayed core. It is preferable that the average particle size of the crushed raw coat is 1-150 m.
  • the pulverized raw coats are pulverized (pulverization in the present invention means turning large particles or agglomerates into powder having a smaller particle diameter. It is preferable to adjust the average particle size to 3-50 / zm.
  • any one of the treatment steps prior to the graphitizing treatment that is, 0.05 to 40% by weight of a graphitization catalyst is added to the heavy oil, the ground raw coals or the carbonized carbonized material. It is preferable to calories.
  • the graphitization catalyst is preferably at least one selected from boron, silicon, iron and compounds thereof.
  • the obtained graphite powder preferably has a BET specific surface area of 10 m 2 Zg or less.
  • heavy coal-based oil (coal tar-based raw material) is obtained from coal tar produced by carbonization of coal, high-boiling tar oil separated from coal tar, tar pitch, and the like. ) Is desirable.
  • it is tar pitch.
  • Talbitsch has a soft pitch with a softening point of 70 ° C or less, a medium pitch with a softening point of about 70-85 ° C, and a high pitch with a softening point of 85 ° C or more. It is advantageous to use a soft pitch for Also, a mixture of two or three types of tar pitch, coal tar or high boiling tar oil may be used.
  • Examples of the petroleum heavy oil include catalytic cracking oil, atmospheric residual oil, and vacuum residual oil.
  • decant oil FCC-DO
  • these heavy oils may be removed by distillation of light components in advance, or may be subjected to heat treatment and heavy polymerization by heat polymerization, in terms of the carbonization yield.
  • Heavy petroleum heavy oils contain almost no QI.
  • the heavy coal oil and the heavy petroleum oil may be used, for example, at a mixing ratio of 10 to 80 wt% of the heavy petroleum oil to the heavy coal oil.
  • the raw coatas refers to semi-solid coatas having a volatile content (weight loss when heated at 950 ° C for 7 minutes) of 3% or more, preferably 5% or more.
  • the production of raw coats with delayed coke is carried out at a coking temperature of 600 ° C or less, usually 400 ° C-600 ° C, preferably 450-500 ° C.
  • the processing temperature may be determined.
  • Raw coats produced in Delayco are cut out using jet water, then the water content is adjusted and crushed.
  • the pulverization is carried out by first using a coarse pulverizer such as a jaw crusher, and then using a fine pulverizer such as a hammer crusher to obtain an average particle diameter of 1 to 50 ⁇ m, preferably 15 to 35 ⁇ m. If the average particle size exceeds 50 m, the thickness of the fuel cell separator as a graphite molded article may be larger than the thinnest part, so that the specific surface area of the obtained graphite material is increased, and the physical properties of the separator are reduced. This leads to a decrease in bulk density, an increase in specific resistance, a decrease in bending strength, and an increase in gas permeability. On the other hand, it is very difficult to grind to an average particle size of less than 1 m, and the surface area increases, so the amount of resin must be increased, which leads to an increase in intrinsic resistance.
  • a coarse pulverizer such as a jaw crusher
  • a fine pulverizer such as a hammer crusher
  • the pulverizer used here is not particularly limited, and any type of pulverizer may be used as long as it has a target average particle diameter.
  • the raw coat is carbonized.
  • the carbonization temperature is preferably 700 ° C to 1500 ° C, more preferably 800 ° C to 1200 ° C.
  • the carbonization treatment may be performed using a lead-nomer-type carbonization furnace that effectively uses waste heat by placing raw coals in a container, or a burner-type batch-type carbonization furnace.
  • the type of furnace is not particularly limited. At a temperature at which volatiles are scattered, it is preferable that the heating rate be as low as about 10 ° C / hr, since the carbonization yield increases, but this is not particularly limited.
  • the graphitization catalyst is preferably one that forms carbide with carbon or one that dissolves in carbon.
  • boron compounds, iron compounds, silicon compounds and their metals are desirable. When these compounds and metals are solid, they can be pulverized and then mixed with the raw materials, or those which are soluble in a solvent, for example, alcohols, can be mixed with the raw materials and used.
  • the compounding ratio of the graphitization catalyst is preferably in the range of 0.05 to 40 wt%.
  • the physical properties of the fuel cell separator can be improved, that is, the bulk density, the specific resistance, the bending strength, and the gas permeability can be reduced.
  • the graphitizing catalyst described above is blended with the carbide heat-treated at 700-1500 ° C. It is good.
  • the compounding ratio of the graphitization catalyst is in the range of 0.05 to 40 wt% with respect to the carbide.
  • the graphite temperature is preferably 2000 ° C or more, more preferably 2500 ° C or more.
  • the average particle diameter of the graphite-treated material is adjusted to 3 to 50 m, and the specific surface area is preferably 10 m 2 / g or less so that the amount used when kneading with the resin is minimized. 5m 2 / g or less is more desirable.
  • the force should be in the range of 1-3.1.6!
  • the raw material obtained by pulverizing the raw coat containing volatiles, firing and graphitizing the material contains volatiles! It has a rounder shape than the graphite-rided product, and greatly contributes to the improvement of the molding yield (cracking or cracking at the time of molding, visual inspection after molding) as a fuel cell separator, and improvement of physical properties. It is considered that
  • the graphite powder used in the present invention may have a single particle size of 3 to 50 m in average particle size to facilitate the pulverization or pulverization of the obtained compound, or a secondary pulverization of graphite particles. If it is desired to further reduce the specific resistance due to the effect, graphite powder having two types of particle size distribution may be used together. That is, a large particle size graphite powder having an average particle size of 50-300 m, preferably 70-150 m, and a small particle size having an average particle size of less than 50 m, preferably 5-20 m. It may be a mixture of graphite powder! / ⁇ .
  • the ratio between the large particle size graphite powder and the small particle size graphite powder is 40: 60-90: 10 by weight.
  • two types of graphite powders large particles are ground during the milling after kneading and a new coat surface emerges, so that a conductive path can be made in contact, while large particles have a small surface area It is expected that kneading is possible even with a small amount of resin. For small particles, it is expected that the strength of molded products will be improved while the contact between graphite particles is improved. It is also effective for increasing the bulk density. Further, if desired, a mixture of isotropic graphite powder and anisotropic graphite powder, for example, a mixture of 40:60 to 90:10 may be used.
  • the epoxy resin binder used in the present invention binds and solidifies graphite powder with a predetermined strength, and also has an epoxy resin and epoxy resin curing agent power. If desired, a curing accelerator can be added to the composition of the present invention or the epoxy resin binder, but it is not calculated as an epoxy resin binder!
  • the epoxy resin blended in the epoxy resin binder of the present invention has a viscosity at 150 ° C. of 120 mPa's, a melting point of 45 ° C. to 130 ° C., preferably 50 ° C. to 130 ° C., at room temperature. It is desirable to use one or more solid low-viscosity crystalline epoxy resins. As a result, at room temperature, the composition or compound is excellent in storage stability, and at the temperature at the time of molding, it shows good fluidity even when a relatively large amount of graphite powder is contained. it can.
  • the epoxy equivalent should be about 150-300 g / eq, preferably 170-250 g / eq.
  • Such a low-viscosity crystalline epoxy resin may be an ether-type or thioether-type epoxy resin represented by the above general formula (1), wherein X is O or S.
  • G is a glycidyl group
  • R is a monovalent group, which is a halogen atom or a hydrocarbon group having 16 carbon atoms which may be the same or different.
  • it is an alkyl group having 13 to 13 carbon atoms, and the number n of the substituents other than the hydrogen atom in one benzene ring is 0 to 4 !.
  • the epoxy resin often contains an oligomer by polymerization of the epoxy resin represented by the general formula (1).
  • the low-viscosity crystalline epoxy resin which is solid at room temperature is contained in the epoxy resin in an amount of 30% by weight or more, preferably 50% by weight or more, and more preferably 80% by weight or more. If another epoxy resin that is not a strong crystalline epoxy resin is used as at least a part of the epoxy resin component, a low-viscosity epoxy resin is preferred, for example, bisphenol F type epoxy resin, Biphenyl type epoxy resin and the like can be mentioned.
  • the curing agent for the epoxy resin may be a known one such as a phenol-based, amine-based, or carboxylic acid-based resin.
  • the curing agent is a polyvalent phenol, and more preferably, a phenol-alkyl phenol. It is a novolak curing agent obtained from formalin. It is advantageous that the novolac curing agent has a softening point at room temperature or higher.
  • the equivalent ratio between the epoxy resin and the curing agent is not particularly limited, but is preferably in the range of 0.5 to 1.5.
  • an epoxy resin curing accelerator When an epoxy resin curing accelerator is blended, known accelerators such as amines, imidazoles, ureas, organic phosphines, and Lewis acids can be used as the curing accelerator.
  • the amount of the curing accelerator is not particularly limited, but is preferably in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the epoxy resin binder.
  • a dimethyl pereas type accelerator is mentioned as a preferable hardening accelerator.
  • the epoxy resin binder comprises an epoxy resin and a curing agent, and advantageously has an epoxy resin viscosity at 150 ° C of 120 mPa's, preferably 15 mPa's or less, more preferably 15 mPa's or less.
  • Epoxy resin containing 1 or more types of crystalline epoxy resin which is 1 OmPa's or less and is solid at room temperature (25 ° C).
  • the crystalline epoxy resin has a melting point of 45 to 130 ° C, preferably 50 to 130 ° C.
  • the epoxy resin may be composed of only the above-mentioned crystalline epoxy resin or may be a mixture with other epoxy resins. Alternatively, the epoxy resin as a whole may have the above viscosity and softness.
  • the epoxy resin binder also has a viscosity at 150 ° C of 500 mPa's or less and a softening point or a melting point of 45 to 130 ° C. As a result, not only is the storage stability excellent, but also good fluidity can be exhibited during molding. It is easy to adjust the viscosity to such a value by selecting the softening point and the viscosity of the epoxy resin and the curing agent.
  • the fuel cell separator composition of the present invention also includes an internal release agent such as stearic acid and wax, and other conductive fillers.
  • an internal release agent such as stearic acid and wax, and other conductive fillers.
  • the graphite powder and the resin binder may be mixed at the same time.
  • the graphite powder having at least two types of particle size distribution may be mixed in advance, and then mixed with the resin binder. ⁇ .
  • a resin component consisting of graphite powder, an epoxy resin binder, a curing accelerator, and additives to be blended as necessary. After heating and kneading, the mixture is pulverized or crushed so that the average particle size is 100 m or less, preferably 20 to 50 m. . C-1 350. C, preferably 140. C-1 230. C, more preferably 150. C-200. It is advantageous to mold and cure in C.
  • kneading is performed using a kneader.
  • a kneader a general-purpose kneader, roll, single-screw extruder, multi-screw extruder, or the like can be used, but is not limited thereto.
  • the kneading is performed so that the resin and the graphite powder form a composition as uniform as possible.
  • heating may be performed to reduce the viscosity of the resin, or a low-boiling solvent may be added, but it is necessary that curing is not completed.
  • the composition obtained by kneading is pulverized or crushed.
  • the pulverization can be performed using a known pulverizer.
  • the pulverizer used here include a pulverizer for shear pulverization and a disk mill for compression pulverization.
  • graphite powders with different average particle sizes are used in this pulverization process, the graphite powder with a large particle size is preferentially pulverized, resulting in the adhesion of grease and the generation of a new graphite fracture surface. This has the effect of lowering the resistance.
  • the graphite powder with an average particle size of 50-300 m used as a raw material is selectively pulverized to 50 m or less, and the graphite powder with an average particle size of less than 50 m is pulverized as much as possible. It is advantageous not to do so. If the pulverization is more than necessary, the resin may not be sufficiently distributed and the strength of the molded article may be reduced.
  • the viscosity at 150 ° C of the compound (crushed product) obtained by grinding as described above is 200 to 3000 Pa's, preferably ⁇ 2000 Pa's or less, more preferably ⁇ 1500 Pa's or less. Or 200-1200Pa ⁇ s!
  • the viscosity at 150 ° C of such a compound is determined by the type of graphite and epoxy resin binder used, the presence or absence of a curing accelerator, the force that varies depending on the kneading temperature and time, etc. It is preferable that the value obtained by measuring the compound obtained under the conditions shown in the examples indicates the above viscosity. This viscosity is determined mainly by selecting the amounts of the epoxy resin and graphite. Although the viscosity of the compound increases when left for a long period of time, the viscosity may be indicated immediately before the compound is used for manufacturing a fuel cell separator.
  • a small amount of components such as graphite powder, an epoxy resin binder, and a curing accelerator added as needed (hereinafter, components other than the graphite material are mainly resin, and are also referred to as resin components, etc.)
  • the composition of the present invention comprises a graphite material and a resin component, and the resin component may contain a small amount of components other than the resin.
  • the composition of the present invention is kneaded, and the kneaded product is pulverized to 100 ⁇ m or less, preferably 3 to 50 ⁇ m, and more preferably 20 to 50 ⁇ m, and then molded to form a fuel cell separator. Is obtained.
  • the pulverized material Since the pulverized material is kneaded at a temperature of about 100 ° C, it is a partially incompletely cured product in which curing is progressing, and is pressed and molded at a temperature of about 140 ° C or more. When held for a predetermined time, it becomes a cured product (molded article or separator).
  • This compound should have a viscosity of 200-3000Pa's at 150 ° C! / ⁇ .
  • the method of forming the separator depends on the mixing ratio of graphite and the resin binder, but press molding, transfer molding, and injection molding using a mold in which holes and grooves in the separator are processed can be used.
  • press molding transfer molding and injection molding are preferred when the amount of resin added is low and when the amount of resin added is relatively large and the compound has fluidity.
  • thermoplastic resin is used, continuous forming using a design roll having a grooved hole is also applicable.
  • the temperature is set to 100 to 350 ° C, preferably 140 to 230 ° C, more preferably about 150 to 200 ° C. It is better to hold it.
  • the temperature should be higher than the curing temperature of the thermosetting resin to be used and lower than the carbonization temperature.
  • the molding pressure is preferably higher to reduce the electrical resistivity in the surface direction and increase the bulk density. Bur, since the equipment cost to increase the pressure increases, 20- lOOOkg / cm 2 or so, preferably 100- 800 kg / cm 2, more preferably suitably about 100- 500kg / cm 2.
  • a separator with a thickness of 2 mm and an area of about 700 cm 2 can be molded within a molding time of less than 20 minutes, especially less than 5 minutes, and a dimensional accuracy of less than 100 / zm, especially less than 50 m.
  • the fuel cell separator can be used as it is or with a simple casing. However, after being formed into a plate or the like, a fuel cell separator is prepared by adding a groove and a hole to the plate to form a fuel cell separator.
  • the fuel cell separator obtained by the production method of the present invention can have a bulk density of 1.80 g / cm 3 or more, preferably 1.85 g / cm 3 or more, and is gas-impermeable and mechanical.
  • the target strength is also excellent.
  • the bulk density is less than 1.80 g / cm 3 , not only gas impermeability is inferior but also mechanical strength is inferior.
  • the specific resistance is required to be 100 m ⁇ cm or less, preferably 40 mQcm or less in order to function as a fuel cell, the required characteristics can be sufficiently achieved.
  • This specific resistance can be lowered by increasing the type of graphite to be used with a high degree of crystallinity or by reducing the amount of the thermosetting resin, and can also be changed by molding pressure and the like.
  • the specific resistance is determined according to the measuring method described in the examples described later.
  • the fuel cell separator of the present invention has a bending strength of 30 MPa or more and a gas permeability of 1
  • the separator may oxygen and hydrogen as fuel if the vibration or shock can become corrupted resistance high instrument gas permeability greater than 1 X 10- 14 cm 2 is mixed power generation Impairs efficiency.
  • the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.
  • the methods for measuring the specific resistance, compound viscosity, and dimensional accuracy of the molded body are as follows.
  • Compound viscosity High-low type flow tester (Shimadzu Flote, manufactured by Shimadzu Corporation) Star CFT-500).
  • the actual nozzle size used in the measurement was ⁇ 1 ⁇ L1.
  • about 2 g of the sample (crushed material) was first compression-molded into a tablet with a size of approximately ⁇ 10 ⁇ L7 at room temperature.
  • the viscosity measuring device which has been heated to the measurement temperature (150 ° C) in advance, hold it for 10 sec, measure the viscosity at a shear rate of 5000 1 / s.
  • Thickness accuracy The thickness of a predetermined portion of a molded body obtained under predetermined molding conditions was measured, and the maximum value-minimum value was defined as the thickness accuracy. In the evaluation of thickness accuracy, ⁇ : less than 50 / ⁇ , ⁇ : less than 50-100 ⁇ m, X: 100 m or more.
  • the molded product was measured by a four-terminal voltage drop method.
  • the specific resistance is measured in the thickness direction (press forming pressure direction) and in the plane direction (perpendicular to the press forming pressure direction).
  • the specific resistance shown in this example is particularly important as a separator characteristic. The values in the thickness direction are shown.
  • the raw materials used are as follows.
  • Highly conductive graphite Lumpy raw coats produced by delayed coking using heavy coal-based oil were pulverized with a Raymond mill to an average particle size of 30 m. This was carbonized at about 800 ° C in a lead normal furnace to obtain carbide. Kurosuzuri was performed at 2800 ° C. with 5% boron carbide added to this carbide.
  • Ether type epoxy resin manufactured by Toto Kasei Co., Ltd., trade name YSLV-80DE, melting point 79 ° C, viscosity at 150 ° C 0.006 Pa's
  • Thioether type epoxy resin manufactured by Toto Kasei Co., Ltd., trade name YSLV-50TE, melting point 50. C, 150 ° C viscosity 0.006Pa's
  • Tetramethylbisphenol F-type epoxy resin manufactured by Nippon Steel Chemical Co., Ltd., trade name YSLV-80XY, melting point 78, viscosity at 150 ° C 0.008 Pa's
  • Phenol novolak resin Tamanol 758 manufactured by Arakawa Chemical Co., Ltd., softening point 83 ° C, 150 ° C viscosity 0.22-0.35Pa's
  • Curing accelerator dimethyl urea-based accelerator Sanapro Co., Ltd., trade name U-CAT3502T
  • Table 1 shows the measurement results of the viscosity (compound viscosity) of the powder frame, the dimensional accuracy of the compact, and the specific resistance.
  • a pulverized product and a molded product were manufactured in the same manner as in Example 1 with the composition shown in Table 1, and the physical properties were measured. The results are shown in Table 1.
  • a pulverized product and a molded product were manufactured in the same manner as in Example 1 with the composition shown in Table 1, and the physical properties were measured. The results are shown in Table 1.
  • EOCN-1020 100 100 100 Tamanol 758 65 65 65 65 63 55 54 54 54 Hardening accelerator 1.6 1.6 1.61-6 1.6 1.6 1.6 1.6 1.6 1.6 Graphite 495 660 825 1155 652 620 462 616 770 Graphite / resin ratio 3 4 5 7 4 4 3 4 5
  • the material which required characteristics as a fuel cell separator ie, electrical conductivity, mechanical strength, etc.
  • the moldability can be further improved.
  • it can provide a compound material that can shorten the molding cycle, has excellent dimensional accuracy, and can be used in mass production of separators in the future, and makes an extremely large contribution in this field.
  • the fuel cell sensor router obtained by the production method of the present invention is dense, has high mechanical strength, has excellent conductivity, has low anisotropy, and has a low gas permeability. A highly efficient, long-life fuel cell can be achieved.

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Abstract

A graphite/resin compound material that while satisfying the performance requirements for fuel cell separator, excels in moldability so as to attain shortening of molding cycle and excel in dimensional accuracy, thereby enabling mass production of separator. There is provided a composition for fuel cell separator comprising graphite powder and an epoxy resin binder, the epoxy resin binder composed of an epoxy resin and a curing agent, which composition is produced by mixing an epoxy resin binder with graphite powder amounting to 3 to 7 times the weight of the epoxy resin binder and thereafter kneading and pulverizing the mixture to thereby obtain a compound whose viscosity at 150°C is in the range of 200 to 3000 Pa·s and whose electric specific resistance in the form of a molding as fuel cell separator is 40 mΩcm or below in terms of resistivity. A crystalline epoxy resin having a viscosity at 150°C of 1 to 20 mPa·s and a melting point of 45 to 130°C and being solid at ordinary temperatures is suitable for the above epoxy resin.

Description

明 細 書  Specification
燃料電池セパレータ用組成物及び燃料電池セパレータの製法  Composition for fuel cell separator and method for producing fuel cell separator
技術分野  Technical field
[0001] 本発明は、燃料電池セパレータ用組成物、特に固体高分子型燃料電池セパレータ に適用され、黒鉛と榭脂を主成分とするセパレータ用組成物、並びにその組成物を 使用した燃料電池セパレータの製造方法に関するものである。  The present invention is applied to a fuel cell separator composition, particularly a polymer electrolyte fuel cell separator, and comprises a graphite and resin-based separator composition, and a fuel cell separator using the composition. And a method for producing the same.
背景技術  Background art
[0002] 自動車搭載用途や家庭コージェネレーション用途等に利用される燃料電池が注目 されている。この燃料電池は、化学エネルギーを熱エネルギーに変換することなく直 接電気エネルギーとして利用するものであり、通常、水素及び酸素の反応によって電 気を取出す電池をいう。こうした燃料電池には、リン酸型燃料電池、固体電解質型燃 料電池及び固体高分子型燃料電池 (PEFC)等いくつかの方式のものがある力 そ の中で PEFC、リン酸型燃料電池では導電性成形品であるセパレータが使用されて いる。セパレータは、電極等と共に単位セルを構成し、該単位セルを積層して使用さ れるものであって、ガス (水素 ·酸素）を隔離する一方で導電性を必要とする。そのた め、固有抵抗が 100m Ω cm以下の高い電気導電性が要求される他、気体透過率が 低いこと、更には機械的強度、耐食性、成形性などが要求される。その要求特性を満 たす材料としては、黒鉛系、金属系に大別される。この場合、黒鉛系では、黒鉛材を 切削加工する切削カーボン、特殊な膨張黒鉛、黒鉛粉末を榭脂で一体化するコンパ ゥンド材などが挙げられる。また、金属系は、電気伝導性や機械強度などで優れるも のの、耐食性が一般に不十分であり表面処理が必要とされていた力 最近ではステ ンレス系も検討されている。  [0002] Fuel cells for use in automobiles, home cogeneration, and the like are receiving attention. This fuel cell uses chemical energy directly as electrical energy without converting it into thermal energy, and usually refers to a battery that extracts electricity by the reaction of hydrogen and oxygen. There are several types of such fuel cells, such as phosphoric acid fuel cells, solid oxide fuel cells, and polymer electrolyte fuel cells (PEFCs). A separator that is a conductive molded product is used. The separator constitutes a unit cell together with electrodes and the like, and is used by stacking the unit cells. The separator needs to have conductivity while isolating gas (hydrogen / oxygen). Therefore, high electrical conductivity with a specific resistance of 100 mΩcm or less is required, low gas permeability, mechanical strength, corrosion resistance, and formability are required. Materials satisfying the required characteristics can be broadly classified into graphite-based materials and metal-based materials. In this case, in the case of graphite, cutting carbon for cutting graphite material, special expanded graphite, compound material for integrating graphite powder with resin, and the like are used. Metallic materials are excellent in electrical conductivity and mechanical strength, but generally have insufficient corrosion resistance and require surface treatment. Recently, stainless steel materials have been studied.
[0003] 黒鉛粉末と榭脂とのコンパゥンド材は、これらの要求特性を黒鉛と榭脂とで機能分 担するものであり、多数検討されている。本発明に関連する先行文献としては、下記 文献がある。  [0003] Compound materials of graphite powder and resin are those whose required properties are shared by graphite and resin, and are being studied in large numbers. Prior art documents related to the present invention include the following documents.
特許文献 1：特開平 4-214072号公報  Patent Document 1: JP-A-4-214072
特許文献 2：特開平 8 - 31231号公報 特許文献 3：特開平 11—195422号公報 Patent Document 2: JP-A-8-31231 Patent Document 3: JP-A-11-195422
特許文献 4：特開平 11-297338号公報 Patent Document 4: JP-A-11-297338
特許文献 5：特開平 2000-40517号公報 Patent Document 5: JP-A-2000-40517
特許文献 6：特開平 2000 - 21421号公報 Patent Document 6: JP-A-2000-21421
特許文献 7：特開 2001— 139696号公報 Patent Document 7: Japanese Patent Application Laid-Open No. 2001-139696
特許文献 8：特開 2001—216976号公報 Patent Document 8: Japanese Patent Application Laid-Open No. 2001-216976
特許文献 9：特開 2002-83609号公報 Patent Document 9: JP-A-2002-83609
特許文献 10：特開 2002— 201257号公報 Patent Document 10: Japanese Patent Application Laid-Open No. 2002-201257
例えば、特許文献 1では、緻密で機械的な強度が大きぐ導電性に優れた燃料電 池用セパレータとして適した炭素材を得るため、バインダーと複数の粒度を有する炭 素質粉粒体とからなる黒鉛ィ匕炭素材を提案している。しかし、この方法は成形後、黒 鉛化処理する必要がある。特許文献 2では、空隙率が 5%以下、成形体の XY方向の 体積固有抵抗と Z方向の体積固有抵抗の比の値が 2以下の燃料電池用セパレータと して適した炭素材を得るため、熱硬化榭脂とケッチェンブラック、真球状黒鉛粒子を 配合した炭素材を提案している。また、特許文献 3では、バインダーの量を減らして、 導電性を向上させるため、カーボン材料に少量のバインダーを配合して加圧成形し 、その後含浸剤を含浸させる方法が提案されている。更に、特許文献 4では、電極部 との接触抵抗が低い燃料電池用セパレータを得るため、表面粗さを一定範囲とした 燃料電池用セパレータを提案している。また、特許文献 5では、異方性の少ない燃料 電池用セパレータを得るため、人造黒鉛と天然黒鉛を併用することを提案している。 特許文献 6では、ガス不透過性、熱伝導性、導電性等のバランスがとれた燃料電池 用セパレータを得るため、特定の黒鉛粉末を使用することを提案している。特許文献 7— 10では、黒鉛とエポキシ榭脂を含む導電性エポキシ榭脂成形材料が記載されて いる。特許文献 7では、エポキシ榭脂としてオルトクレゾールノボラック型エポキシ榭 脂又はビスフエノール型エポキシ榭脂を使用して 、るが、ビスフエノール型エポキシ 榭脂としては具体的にはビスフエノール A型エポキシ榭脂を開示するにとどまる。特 許文献 8では、エポキシ榭脂として具体的にはビスフエノール F型エポキシ榭脂を開 示するにとどまる。特許文献 9一 10では、エポキシ榭脂として具体的にはタレゾール ノボラック型エポキシ榭脂を開示するにとどまる。 For example, in Patent Document 1, in order to obtain a carbon material suitable as a fuel cell separator having a dense and high mechanical strength and excellent conductivity, a carbon material comprising a binder and a plurality of particle sizes is used to obtain a carbon material suitable for a fuel cell separator. A graphite carbon material has been proposed. However, this method requires graphitization after molding. In Patent Document 2, in order to obtain a carbon material suitable for a fuel cell separator having a porosity of 5% or less and a ratio of a volume resistivity in the XY direction to a volume resistivity in the Z direction of the molded body of 2 or less. We have proposed a carbon material blended with thermosetting resin, Ketjen Black and spherical graphite particles. Patent Document 3 proposes a method in which a small amount of a binder is blended with a carbon material, pressure-formed, and then impregnated with an impregnating agent in order to reduce the amount of the binder and improve conductivity. Further, Patent Document 4 proposes a fuel cell separator having a certain range of surface roughness in order to obtain a fuel cell separator having a low contact resistance with an electrode portion. Patent Document 5 proposes that artificial graphite and natural graphite be used together in order to obtain a fuel cell separator with low anisotropy. Patent Document 6 proposes to use a specific graphite powder in order to obtain a fuel cell separator having a good balance of gas impermeability, thermal conductivity, conductivity, and the like. Patent Documents 7 to 10 disclose a conductive epoxy resin molding material containing graphite and epoxy resin. In Patent Document 7, ortho-cresol novolak type epoxy resin or bisphenol type epoxy resin is used as the epoxy resin. However, the bisphenol type epoxy resin is specifically a bisphenol A type epoxy resin. To disclose. Patent Document 8 discloses only a bisphenol F-type epoxy resin as an epoxy resin. Patent Documents 9 and 10 disclose that as an epoxy resin, It only discloses a novolak type epoxy resin.
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0005] し力しながら、黒鉛と榭脂とのコンパウンド系材料において、燃料電池セパレータと しての要求特性、即ち電気伝導性、機械的強度などを満たしつつ、成形性をより高 めた材料が望まれている。そこで、本発明は、成形サイクルを短縮し、かつ寸法精度 も優れ、今後のセパレータ量産化にも適する成形材料を提供することを目的とする。 課題を解決するための手段  [0005] In the compound material of graphite and resin, a material that satisfies the characteristics required for a fuel cell separator, that is, electrical conductivity, mechanical strength, etc., and further enhances formability. Is desired. Therefore, an object of the present invention is to provide a molding material that shortens the molding cycle, has excellent dimensional accuracy, and is suitable for mass production of separators in the future. Means for solving the problem
[0006] 本発明者らは、カゝかる課題を解決するために鋭意検討した結果、榭脂として、常温 では固形でありながら、高温溶融時には低粘度を示すエポキシ榭脂を所定割合で黒 鉛粉と配合することにより、上記課題を解決できることを見出し、本発明を完成した。  [0006] The inventors of the present invention have conducted intensive studies to solve such a problem, and as a result, as a resin, an epoxy resin which is solid at normal temperature but exhibits low viscosity at the time of high-temperature melting is graphite at a predetermined ratio. The present inventors have found that the above problems can be solved by blending with a powder, and have completed the present invention.
[0007] 本発明は、エポキシ榭脂結合剤と黒鉛粉を含有する組成物にお!/ヽて、エポキシ榭 脂結合剤に対し、黒鉛粉を重量比で 2— 10倍量、好ましくは 3— 7倍量配合し、黒鉛 粉とエポキシ榭脂結合剤との混練後におけるコンパウンド粘度が 200— 3000Pa'sで あり、電気比抵抗が 100m Ω cm以下、好ましくは 40m Ω cm以下であることを特徴とす る燃料電池セパレータ用組成物である。  [0007] The present invention relates to a composition containing an epoxy resin binder and graphite powder, wherein the weight ratio of the graphite powder to the epoxy resin binder is 2 to 10 times, preferably 3 to 10 times. — Compounded in a 7-fold amount, compound viscosity after kneading graphite powder and epoxy resin binder is 200-3000Pa's, and electrical resistivity is 100mΩcm or less, preferably 40mΩcm or less. This is a fuel cell separator composition.
この場合、エポキシ榭脂結合剤が、エポキシ榭脂と硬化剤力もなり、エポキシ榭脂 力 150°Cにおける粘度 1一 20mPa's、融点 45°C— 130°C、好ましくは 50°C— 130°C 、常温で固体である結晶性エポキシ榭脂を 1種以上含むことがょ 、。  In this case, the epoxy resin binder becomes the epoxy resin and the curing agent power, and the epoxy resin power has a viscosity of 120 mPa's at 150 ° C, a melting point of 45 ° C to 130 ° C, and preferably 50 ° C to 130 ° C. And may contain one or more crystalline epoxy resins that are solid at room temperature.
また、本発明は、エポキシ榭脂結合剤と黒鉛粉を含有する組成物において、ェポキ シ榭脂結合剤に対し黒鉛粉を重量比で 2— 10倍量、好ましくは 3— 7倍量配合し、ェ ポキシ榭脂結合剤がエポキシ榭脂と硬化剤カゝらなり、エポキシ榭脂が結晶性であり、 150°Cにおける粘度が 1一 20mPa's、融点が 45°C— 130°Cで、好ましくは 50°C— 1 30°C、常温固体である結晶性エポキシ榭脂を 1種以上含むことを特徴とする燃料電 池セパレータ用組成物である。  Further, the present invention provides a composition containing an epoxy resin binder and graphite powder, in which 2 to 10 times, preferably 3 to 7 times, the weight ratio of graphite powder to the epoxy resin binder is blended. The epoxy resin binder is composed of an epoxy resin and a curing agent, and the epoxy resin is crystalline. The viscosity at 150 ° C is 120 mPa's, and the melting point is 45 ° C-130 ° C. Is a composition for a fuel cell separator comprising at least one kind of crystalline epoxy resin which is a solid at 50 ° C. to 130 ° C. and room temperature.
[0008] エポキシ榭脂結合剤に使用される結晶性エポキシ榭脂としては、下記一般式（1) [化 1] [0008] The crystalline epoxy resin used for the epoxy resin binder includes the following general formula (1):
Figure imgf000005_0001
Figure imgf000005_0001
(但し、 Gはグリシジル基を示し、 Rは 1価の基を示し、 nは 0— 4の整数を示し、 Xは 2 価の基を示す)で表されるエポキシ榭脂が適する。好ましくは、 Xが O又は Sであるェ 一テル型エポキシ榭脂又はチォエーテル型エポキシ榭脂である。 (Where G represents a glycidyl group, R represents a monovalent group, n represents an integer of 0-4, and X represents a divalent group). Preferably, it is an ether type epoxy resin or a thioether type epoxy resin wherein X is O or S.
本発明の燃料電池セパレータの製造方法は、カゝかる組成物を、混練した後、粉砕 し、該粉砕物を温度 100— 350°C、好ましくは 140— 230°Cで成形、硬化することを 特徴とする。本発明の燃料電池セパレータはカゝかる製造方法により得られたものであ る。  The method for producing a fuel cell separator of the present invention comprises kneading, pulverizing, and then molding and curing the pulverized product at a temperature of 100 to 350 ° C, preferably 140 to 230 ° C. Features. The fuel cell separator of the present invention is obtained by a small manufacturing method.
[0009] 燃料電池セパレータは、単位セルを複数積層して構成する燃料電池において、隣 接する単位セル間に設けられ、電極との間で燃料ガス流路、酸化ガス流路を形成し 、燃料ガスと酸ィ匕ガスとを隔てる作用を有するものであり、ガス流路用の溝等が形成 されている。本発明で製造する燃料電池セパレータは、黒鉛粉と熱硬化榭脂とが所 定の形状に成形、硬化されてなるものであり、そのまま、又は必要により溝加工、穴あ けカ卩ェ等がなされて燃料電池セパレータとして使用される。また、燃料電池セパレー タというときは、加工前の燃料電池セパレータ用の成形品を含む意味に解される。  The fuel cell separator is provided between adjacent unit cells in a fuel cell configured by stacking a plurality of unit cells, and forms a fuel gas flow path and an oxidizing gas flow path with an electrode. And has a function to separate the gas from the oxidizing gas, and a groove or the like for a gas flow path is formed. The fuel cell separator manufactured by the present invention is obtained by molding and curing graphite powder and thermosetting resin into a predetermined shape. As such or as necessary, groove processing, drilling, and the like are performed. It is used as a fuel cell separator. Further, the term “fuel cell separator” is understood to include a molded product for a fuel cell separator before processing.
[0010] 本発明の燃料電池セパレータ用組成物は、黒鉛粉とエポキシ榭脂結合剤を必須 成分として含有する。更に、通常、硬化促進剤を含有する。黒鉛粉とエポキシ榭脂結 合剤配合割合は、エポキシ榭脂結合剤 1重量部に対し、黒鉛粉 2— 10重量部、好ま しくは 3— 7重量部である。黒鉛粉が多 、と成形時の流動性が劣り成形に多大な圧力 が必要となって成形機のコストの増加を招ぐ一方、黒鉛粉が少ないと電気伝導性が 不十分となる。  [0010] The fuel cell separator composition of the present invention contains graphite powder and an epoxy resin binder as essential components. Further, it usually contains a curing accelerator. The mixing ratio of the graphite powder and the epoxy resin binder is 2 to 10 parts by weight, preferably 3 to 7 parts by weight, per 1 part by weight of the epoxy resin binder. If the amount of graphite powder is large, the fluidity during molding is inferior and a large amount of pressure is required for molding, which increases the cost of the molding machine. On the other hand, if the amount of graphite powder is small, the electrical conductivity becomes insufficient.
[0011] 本発明で使用する黒鉛粉は高い導電性を示すものであれば制限はなぐ例えば、 メソカーボンマイクロビーズなどの炭素質を黒鉛ィ匕したもの、石炭系コータスや石油 系コータスを黒船ィ匕したものの他、黒鉛電極や特殊炭素材料の加工粉、天然黒鉛、 キッシュ黒鉛、膨張黒鉛の少なくとも 1種類が使用される。 [0011] The graphite powder used in the present invention is not limited as long as it exhibits high conductivity. For example, carbonaceous materials such as mesocarbon microbeads are graphitized, and coal-based coats and petroleum-based coatas are manufactured by Kurofune. In addition to the daggered, graphite electrode and processing powder of special carbon material, natural graphite, At least one of quiche graphite and expanded graphite is used.
[0012] 特に、本発明においては、石炭系及び Z又は石油系重質油の 1種以上を原料とし て用い、 600°C以下で処理して生コータスを生成し、該生コ一タスを粉砕した後、該 粉碎生コ一タスを 700— 1500°Cで炭化、次いで 2000°C以上で黒鉛ィ匕したものが好 ましい。この場合、生コータスは、特にディレードコ一力一によつて熱処理して生成さ せるとよい。粉砕生コータスの平均粒径が 1一 50 mであることが好ましい。更に、粉 砕生コータスを炭化後又は黒船ィ匕後において、粉砕 (本発明でいう粉砕は、大きな 粒子又は塊状物をより粒径の小さな粉体にすることをいい、その手段には制限はな い。例えば、解砕を含む。）して平均粒径 3— 50 /z mに粒度調整することが好ましい [0012] In particular, in the present invention, one or more of coal-based and Z- or petroleum-based heavy oils are used as raw materials, and are treated at 600 ° C or lower to produce raw coats, and the raw coats are processed. After pulverization, it is preferable that the ground raw material is carbonized at 700 to 1500 ° C and then graphited at 2000 ° C or higher. In this case, it is preferable that the raw coat is formed by heat treatment, particularly by using a delayed core. It is preferable that the average particle size of the crushed raw coat is 1-150 m. In addition, after carbonizing or Kurofune Iridani the pulverized raw coats are pulverized (pulverization in the present invention means turning large particles or agglomerates into powder having a smaller particle diameter. It is preferable to adjust the average particle size to 3-50 / zm.
[0013] また、黒鉛ィ匕処理より前のいずれかの処理工程において、すなわち前記重質油、 粉碎生コ一タス又は炭化処理後の炭化物に、黒鉛化触媒を 0. 05— 40重量％添カロ することが好ましい。黒鉛化触媒としては、ホウ素、珪素、鉄及びこれらの化合物から 選択される 1種以上であることが好ましい。得られる黒鉛粉は、 BET比表面積が 10m 2Zg以下であることが好まし 、。 [0013] In any one of the treatment steps prior to the graphitizing treatment, that is, 0.05 to 40% by weight of a graphitization catalyst is added to the heavy oil, the ground raw coals or the carbonized carbonized material. It is preferable to calories. The graphitization catalyst is preferably at least one selected from boron, silicon, iron and compounds thereof. The obtained graphite powder preferably has a BET specific surface area of 10 m 2 Zg or less.
[0014] ここで、石炭系重質油（コールタール系原料）は、石炭を乾留する際生成するコー ルタール並びにコールタールから分離される高沸点タール油及びタールピッチ等で キノリン不溶分 (QI分)を除去したものが望ましい。好ましくはタールピッチである。タ 一ルビッチは、軟化点 70°C以下の軟ピッチ、軟化点 70— 85°C程度の中ピッチ及び 軟化点 85°C以上の高ピッチがあり、いずれも使用可能であるが、取扱いの点で軟ピ ツチを使用することが有利である。また、タールピッチ、コールタール又は高沸点ター ル油の 2又は 3種類を混合したものであってもよい。  [0014] Here, heavy coal-based oil (coal tar-based raw material) is obtained from coal tar produced by carbonization of coal, high-boiling tar oil separated from coal tar, tar pitch, and the like. ) Is desirable. Preferably, it is tar pitch. Talbitsch has a soft pitch with a softening point of 70 ° C or less, a medium pitch with a softening point of about 70-85 ° C, and a high pitch with a softening point of 85 ° C or more. It is advantageous to use a soft pitch for Also, a mixture of two or three types of tar pitch, coal tar or high boiling tar oil may be used.
[0015] また、石油系重質油は、接触分解油、常圧残油、減圧残油等が挙げられる。特に、 石油の流動接触分解油重質成分であるデカント油（FCC-DO)が好ましい。更に、こ れらの重質油は、炭化収率の面力もあらかじめ軽質成分を蒸留により除去するか又 は熱処理して熱重合により重質ィ匕しても良い。力かる石油系重質油には、 QI分は殆 ど含まれていない。なお、これら石炭系重質油と石油系重質油とを、例えば石炭系重 質油に対する石油系重質油の混合率を 10— 80wt%で混合して使用してもよい。 [0016] 生コータスとは、揮発分（950°Cで 7分間加熱した時の重量減少）が 3%以上、好ま しくは 5%以上の半生コータスをいう。ディレードコ一力一での生コータスの製造は、コ 一キング温度が 600°C以下、通常 400°C— 600°C、好ましくは 450— 500°Cである 1S 目的とする揮発分に応じて、処理温度を決めればよい。ディレードコ一力一内で 製造した生コータスは、ジヱット水を用いて切り出された後、水分を調整し、粉砕する 。粉砕は、まずジョークラッシャー等の粗粉砕機で粉砕した後に、ハンマークラッシャ 一タイプ等の微粉砕機で平均粒径 1一 50 μ m、好ましくは平均粒径 15— 35 μ mに 粉砕する。平均粒径 50 mを超えると、黒鉛成形体としての燃料電池セパレータの 厚みが最も薄い部分より大きくなることもあるため、得られる黒鉛材の比表面積が大き くなり、ひいてはセパレータの物性低下、特に嵩密度低下、固有抵抗増大、曲げ強 度低下、気体透過率増大に繋がる。一方、平均粒径 1 m未満に粉砕するのは非常 に難しぐまた表面積が増大するために樹脂の量を増やさなければならず、固有抵 抗の増大に繋がる。 [0015] Examples of the petroleum heavy oil include catalytic cracking oil, atmospheric residual oil, and vacuum residual oil. In particular, decant oil (FCC-DO), which is a heavy component of petroleum fluidized catalytic cracking oil, is preferable. In addition, these heavy oils may be removed by distillation of light components in advance, or may be subjected to heat treatment and heavy polymerization by heat polymerization, in terms of the carbonization yield. Heavy petroleum heavy oils contain almost no QI. The heavy coal oil and the heavy petroleum oil may be used, for example, at a mixing ratio of 10 to 80 wt% of the heavy petroleum oil to the heavy coal oil. [0016] The raw coatas refers to semi-solid coatas having a volatile content (weight loss when heated at 950 ° C for 7 minutes) of 3% or more, preferably 5% or more. The production of raw coats with delayed coke is carried out at a coking temperature of 600 ° C or less, usually 400 ° C-600 ° C, preferably 450-500 ° C. The processing temperature may be determined. Raw coats produced in Delayco are cut out using jet water, then the water content is adjusted and crushed. The pulverization is carried out by first using a coarse pulverizer such as a jaw crusher, and then using a fine pulverizer such as a hammer crusher to obtain an average particle diameter of 1 to 50 μm, preferably 15 to 35 μm. If the average particle size exceeds 50 m, the thickness of the fuel cell separator as a graphite molded article may be larger than the thinnest part, so that the specific surface area of the obtained graphite material is increased, and the physical properties of the separator are reduced. This leads to a decrease in bulk density, an increase in specific resistance, a decrease in bending strength, and an increase in gas permeability. On the other hand, it is very difficult to grind to an average particle size of less than 1 m, and the surface area increases, so the amount of resin must be increased, which leads to an increase in intrinsic resistance.
[0017] ここでの粉砕機は特に限定するものではなぐ目的の平均粒径になればどのタイプ の粉砕機を使用しても良い。この粉砕後、生コータスを炭化処理する。炭化処理温度 は、 700°C— 1500°Cが好ましぐ 800°C— 1200°Cが更に望ましい。炭化処理は、生 コ一タスを容器に入れて、廃熱を有効に利用するリードノヽンマータイプの炭化炉を用 いても良いし、バーナータイプのバッチ式の炭化処理炉を用いても良ぐ炉の型式は 特に制限するものではない。昇温速度は揮発分が飛散する温度では、約 10°C/hrと 非常に遅くする方が、炭化収率が高くなるので好ましいが、特に制限するものではな い。  [0017] The pulverizer used here is not particularly limited, and any type of pulverizer may be used as long as it has a target average particle diameter. After this pulverization, the raw coat is carbonized. The carbonization temperature is preferably 700 ° C to 1500 ° C, more preferably 800 ° C to 1200 ° C. The carbonization treatment may be performed using a lead-nomer-type carbonization furnace that effectively uses waste heat by placing raw coals in a container, or a burner-type batch-type carbonization furnace. The type of furnace is not particularly limited. At a temperature at which volatiles are scattered, it is preferable that the heating rate be as low as about 10 ° C / hr, since the carbonization yield increases, but this is not particularly limited.
[0018] また、ディレードコ一力一での生コータスを製造する時に黒鉛ィ匕触媒を原料に配合 した後にコーキングを行うことができる。黒鉛化触媒は、炭素と炭化物を作るものや炭 素に溶解するものが好ましい。特に、硼素化合物、鉄化合物、珪素化合物やそれら の金属が望ましい。これらの化合物や金属は固体の場合は粉砕をした後に原料に配 合することができるし、溶媒、例えばアルコール類に溶解するものについては原料に 配合して使用しても良い。黒鉛化触媒の配合割合は、 0. 05— 40wt%の範囲がよい 。黒鉛化触媒を添加することによって、得られる黒鉛材の黒鉛構造をより発達させる ことができ、ひいては燃料電池セパレータの物性向上、すなわち嵩密度向上、固有 抵抗低減、曲げ強度向上、気体透過率低減に繋げることができる。 [0018] Further, when producing a raw coat using a delay core, coking can be performed after the graphite catalyst is mixed with the raw material. The graphitization catalyst is preferably one that forms carbide with carbon or one that dissolves in carbon. In particular, boron compounds, iron compounds, silicon compounds and their metals are desirable. When these compounds and metals are solid, they can be pulverized and then mixed with the raw materials, or those which are soluble in a solvent, for example, alcohols, can be mixed with the raw materials and used. The compounding ratio of the graphitization catalyst is preferably in the range of 0.05 to 40 wt%. By adding a graphitization catalyst, further develop the graphite structure of the resulting graphite material As a result, the physical properties of the fuel cell separator can be improved, that is, the bulk density, the specific resistance, the bending strength, and the gas permeability can be reduced.
[0019] 生コータスを製造する時に黒鉛化触媒を添加しな!ヽ場合は、生コータスを粉砕した 後に、 700— 1500°Cで熱処理した炭化物に上記のような黒鉛ィ匕触媒を配合してもよ い。この場合の黒鉛化触媒の配合割合は、炭化物に対し 0. 05— 40wt%の範囲で ある。 [0019] If a graphitization catalyst is not added during the production of raw coatas, if the raw coatas is pulverized, then the graphitizing catalyst described above is blended with the carbide heat-treated at 700-1500 ° C. It is good. In this case, the compounding ratio of the graphitization catalyst is in the range of 0.05 to 40 wt% with respect to the carbide.
[0020] 炭化物の黒鉛ィ匕処理は、炭化物を黒鉛容器に入れた後に、黒鉛粉のジュール熱 で黒鉛化する間接通電タイプのアチソン炉ゃ、黒鉛容器に電流を流し加熱する LW Gタイプの黒鉛ィ匕炉や、高周波誘導炉ゃ黒鉛化雰囲気が調整できる連続黒鉛化炉 等で黒船ィ匕するのが良い。黒鉛ィ匕温度は、 2000°C以上が好ましぐ 2500°C以上が より望ましい。黒鉛ィ匕処理をした材料は平均粒径を 3— 50 mに調整し、比表面積は 、榭脂と混練するときの使用量ができるだけ少なくなるように 10m2/g以下であること が好ましぐ 5m2/g以下がより望ましい。 [0020] In the graphite sizing treatment of carbide, an Acheson furnace の of an indirectly energizing type in which the carbide is put into a graphite container and then graphitized by the Joule heat of the graphite powder, and an LWG type graphite in which an electric current is applied to the graphite container to heat the graphite container. It is preferable to perform the graphite filing in a furnace or a high frequency induction furnace or a continuous graphitization furnace in which the graphitizing atmosphere can be adjusted. The graphite temperature is preferably 2000 ° C or more, more preferably 2500 ° C or more. The average particle diameter of the graphite-treated material is adjusted to 3 to 50 m, and the specific surface area is preferably 10 m 2 / g or less so that the amount used when kneading with the resin is minimized. 5m 2 / g or less is more desirable.
[0021] このようにして得られる黒鉛粉は、所定の粒度分布を有することが好ま U、。すなわ ち、黒鉛粉の粒度分布をロジンラムラ一分布（Rosin- Rammler's distribution)の式： R= 100exp(-adn)  [0021] The graphite powder thus obtained preferably has a predetermined particle size distribution. That is, the particle size distribution of graphite powder is calculated by the formula of Rosin-Rammler's distribution: R = 100exp (-adn)
(式中、 Rは分布量累積値の篩上（％)、 dは粒径（ m)、 aは定数を示す)で表したと き、 nの値力 ^1. 2-2. 0、好ましくは 1. 3-1. 6の範囲にあること力 子まし!/、。  (Where R is the sieve (%) of the cumulative distribution value, d is the particle size (m), and a is a constant), the power of n ^ 1.2-2.0, Preferably, the force should be in the range of 1-3.1.6!
[0022] なお、揮発分を含有した状態の生コータスを粉砕して、焼成、黒鉛化処理して得ら れた材料は、揮発分を含有して!/ヽな 、状態のか焼コータスを粉砕して黒鉛ィ匕したも のよりも形状が丸くなっており、燃料電池用セパレータとしての成形歩留り（成形時の 割れやかけ、成形後の外観目視検査)や物性値等の向上に大いに寄与して 、るもの と考えられる。 [0022] The raw material obtained by pulverizing the raw coat containing volatiles, firing and graphitizing the material contains volatiles! It has a rounder shape than the graphite-rided product, and greatly contributes to the improvement of the molding yield (cracking or cracking at the time of molding, visual inspection after molding) as a fuel cell separator, and improvement of physical properties. It is considered that
[0023] また、本発明で使用する黒鉛粉は、得られたコンパゥンドの粉砕又は解砕を容易に するために平均粒径 3— 50 mの単一粒度でも良いし、黒鉛粒子の二次粉砕効果 により更に固有抵抗を下げたい場合は、 2種類の粒度分布を有する黒鉛粉を併せて 使用しても良い。即ち平均粒径 50— 300 m、好ましくは平均粒径 70— 150 mの 大粒径黒鉛粉と、平均粒径 50 m未満、好ましくは平均粒径 5— 20 mの小粒径 黒鉛粉の混合物であってもよ!/ヽ。大粒径黒鉛粉と小粒径黒鉛粉の割合は重量比で 4 0 : 60— 90 : 10である。 2種類の黒鉛粉を使用することにより、大きい粒子については 、混練後の粉砕の際、粉砕されて新しいコータス面が出るために、接触して導電パス ができる一方、大きい粒子は表面積が小さいため、少量の榭脂量でも混練を可能と することが期待される。小さい粒子については、黒鉛粒子同士の接触性を高める一 方、成形品の強度を高めることが期待される。また、嵩密度を上げるためにも有効で ある。更に、所望により、等方性黒鉛粉と異方性黒鉛粉の混合物、例えば 40 : 60— 9 0 : 10の混合物であってもよい。 [0023] The graphite powder used in the present invention may have a single particle size of 3 to 50 m in average particle size to facilitate the pulverization or pulverization of the obtained compound, or a secondary pulverization of graphite particles. If it is desired to further reduce the specific resistance due to the effect, graphite powder having two types of particle size distribution may be used together. That is, a large particle size graphite powder having an average particle size of 50-300 m, preferably 70-150 m, and a small particle size having an average particle size of less than 50 m, preferably 5-20 m. It may be a mixture of graphite powder! / ヽ. The ratio between the large particle size graphite powder and the small particle size graphite powder is 40: 60-90: 10 by weight. By using two types of graphite powders, large particles are ground during the milling after kneading and a new coat surface emerges, so that a conductive path can be made in contact, while large particles have a small surface area It is expected that kneading is possible even with a small amount of resin. For small particles, it is expected that the strength of molded products will be improved while the contact between graphite particles is improved. It is also effective for increasing the bulk density. Further, if desired, a mixture of isotropic graphite powder and anisotropic graphite powder, for example, a mixture of 40:60 to 90:10 may be used.
[0024] 本発明で使用するエポキシ榭脂結合剤は、黒鉛粉を所定の強度に結合、固化する ものであり、エポキシ榭脂とエポキシ榭脂硬化剤力もなる。所望により硬化促進剤を 本発明の組成物又はエポキシ榭脂結合剤に配合することも可能であるが、エポキシ 榭脂結合剤としては計算しな!ヽ。  [0024] The epoxy resin binder used in the present invention binds and solidifies graphite powder with a predetermined strength, and also has an epoxy resin and epoxy resin curing agent power. If desired, a curing accelerator can be added to the composition of the present invention or the epoxy resin binder, but it is not calculated as an epoxy resin binder!
[0025] 本発明のエポキシ榭脂結合剤に配合されるエポキシ榭脂は、 150°Cにおける粘度 1一 20mPa's、融点 45°C— 130°C、好ましくは 50°C— 130°C、常温で固体である低 粘度結晶性エポキシ榭脂を 1種以上使用することが望ましい。これによつて、常温時 には組成物又はコンパウンドとしての保存安定性に優れると共に、成形時の温度に おいて、黒鉛粉を比較的多量に含有しても、良好な流動性を示すことができる。また 、エポキシ当量としては、 150— 300g/eq程度、好ましくは 170— 250g/eqのものに するとよ 、。  The epoxy resin blended in the epoxy resin binder of the present invention has a viscosity at 150 ° C. of 120 mPa's, a melting point of 45 ° C. to 130 ° C., preferably 50 ° C. to 130 ° C., at room temperature. It is desirable to use one or more solid low-viscosity crystalline epoxy resins. As a result, at room temperature, the composition or compound is excellent in storage stability, and at the temperature at the time of molding, it shows good fluidity even when a relatively large amount of graphite powder is contained. it can. The epoxy equivalent should be about 150-300 g / eq, preferably 170-250 g / eq.
[0026] こうした低粘度結晶性エポキシ榭脂としては、上記一般式（1)で表され、 Xが O又は Sであるエーテル型又はチォエーテル型エポキシ榭脂であることがょ 、。一般式（1) において、 Gはグリシジル基であり、 Rは 1価の基を示す力 同一であっても異なって もよいハロゲン原子又は炭素数 1一 6の炭化水素基であることがよぐ好ましくは炭素 数 1一 3のアルキル基であり、一つのベンゼン環が有する水素原子以外の置換基の 数 nは 0— 4個であることがよ!、。  [0026] Such a low-viscosity crystalline epoxy resin may be an ether-type or thioether-type epoxy resin represented by the above general formula (1), wherein X is O or S. In the general formula (1), G is a glycidyl group, and R is a monovalent group, which is a halogen atom or a hydrocarbon group having 16 carbon atoms which may be the same or different. Preferably, it is an alkyl group having 13 to 13 carbon atoms, and the number n of the substituents other than the hydrogen atom in one benzene ring is 0 to 4 !.
なお、周知のようにエポキシ榭脂は、一般式（1)で表されるエポキシ榭脂が重合し てオリゴマーを含むことが多い。一般式（1)で表されるエポキシ榭脂の重合度 m=0 とすると、 m= l以上のオリゴマーは 50wt%以下、好ましくは 10wt%以下であることが よい。 As is well known, the epoxy resin often contains an oligomer by polymerization of the epoxy resin represented by the general formula (1). Assuming that the polymerization degree of the epoxy resin represented by the general formula (1) is m = 0, the oligomer having m = l or more may be 50% by weight or less, preferably 10% by weight or less. Good.
こうした常温で固体である低粘度結晶性エポキシ榭脂が、エポキシ榭脂中に、 30 重量％以上、好ましくは 50重量％以上、更に好ましくは 80重量％以上含有している こと力 Sよい。力かる結晶性エポキシ榭脂に該当しない他のエポキシ榭脂をエポキシ榭 脂成分の少なくとも一部として使用する場合は、低粘度エポキシ榭脂が好ましぐ例 えば、ビスフエノール F型エポキシ榭脂、ビフエニル型エポキシ榭脂等が挙げられる。  The low-viscosity crystalline epoxy resin which is solid at room temperature is contained in the epoxy resin in an amount of 30% by weight or more, preferably 50% by weight or more, and more preferably 80% by weight or more. If another epoxy resin that is not a strong crystalline epoxy resin is used as at least a part of the epoxy resin component, a low-viscosity epoxy resin is preferred, for example, bisphenol F type epoxy resin, Biphenyl type epoxy resin and the like can be mentioned.
[0027] エポキシ榭脂の硬化剤は、フエノール系、アミン系、カルボン酸系等の公知のもの を使用することができる力 好ましくは多価フエノール類であり、より好ましくはフエノー ルゃアルキルフ ノールとホルマリンから得られるノボラック系の硬化剤である。ノボラ ック系の硬化剤は、軟ィ匕点が常温以上であるものが有利である。エポキシ榭脂と硬化 剤の当量比は特に限定されないが、 0.5— 1.5の範囲が好ましい。 [0027] The curing agent for the epoxy resin may be a known one such as a phenol-based, amine-based, or carboxylic acid-based resin. Preferably, the curing agent is a polyvalent phenol, and more preferably, a phenol-alkyl phenol. It is a novolak curing agent obtained from formalin. It is advantageous that the novolac curing agent has a softening point at room temperature or higher. The equivalent ratio between the epoxy resin and the curing agent is not particularly limited, but is preferably in the range of 0.5 to 1.5.
[0028] エポキシ榭脂の硬化促進剤を配合する場合、硬化促進剤としては、アミン類、イミダ ゾール類、ウレァ類、有機ホスフィン類、ルイス酸等の公知の促進剤が使用できる。 硬化促進剤の配合量は特に限定されないが、エポキシ榭脂結合剤 100重量部に対 し、 0.01— 10重量部の範囲が好ましい。ジメチルゥレア系促進剤は好ましい硬化促 進剤として挙げられる。 When an epoxy resin curing accelerator is blended, known accelerators such as amines, imidazoles, ureas, organic phosphines, and Lewis acids can be used as the curing accelerator. The amount of the curing accelerator is not particularly limited, but is preferably in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the epoxy resin binder. A dimethyl pereas type accelerator is mentioned as a preferable hardening accelerator.
[0029] エポキシ榭脂結合剤は、エポキシ榭脂と硬化剤カゝらなり、有利にはエポキシ榭脂と して 150°Cにおける粘度が 1一 20mPa' s、好ましくは 15mPa's以下、より好ましくは 1 OmPa' s以下であって、常温（25°C)固体の結晶性エポキシ榭脂を 1種以上含むェポ キシ榭脂である。この結晶性エポキシ榭脂の融点は、 45— 130°C、好ましくは 50— 1 30°Cであることがよい。そして、エポキシ榭脂は、上記結晶性エポキシ榭脂のみから なるものであってもよぐ他のエポキシ榭脂との混合物であってもよいが、エポキシ榭 脂全体としても、上記粘度と軟ィ匕点又は融点を有し、常温固体であることが望ましい 。更に、エポキシ榭脂結合剤としても 150°Cにおける粘度が 500mPa' s以下で、軟ィ匕 点又は融点が 45— 130°Cであることが望ましい。これによつて、保存安定性に優れる と共に、成形時において、良好な流動性を示すことができる。このような粘度に調整 することは、上記エポキシ榭脂と硬化剤の軟化点や粘度を選択することにより容易で ある。 [0030] また、本発明の燃料電池セパレータ組成物には、黒鉛粉、榭脂結合剤とエポキシ 榭脂硬化促進剤の他に、ステアリン酸やワックス等の内部離型剤、他の導電性フイラ 一等の添加材を本発明の効果を妨げない範囲で配合することもできるが、これらは、 榭脂結合剤あるいは黒鉛粉としては計算しな!、。 [0029] The epoxy resin binder comprises an epoxy resin and a curing agent, and advantageously has an epoxy resin viscosity at 150 ° C of 120 mPa's, preferably 15 mPa's or less, more preferably 15 mPa's or less. Epoxy resin containing 1 or more types of crystalline epoxy resin which is 1 OmPa's or less and is solid at room temperature (25 ° C). The crystalline epoxy resin has a melting point of 45 to 130 ° C, preferably 50 to 130 ° C. The epoxy resin may be composed of only the above-mentioned crystalline epoxy resin or may be a mixture with other epoxy resins. Alternatively, the epoxy resin as a whole may have the above viscosity and softness. It is desirable to have a dangling point or melting point and to be a solid at room temperature. Further, it is desirable that the epoxy resin binder also has a viscosity at 150 ° C of 500 mPa's or less and a softening point or a melting point of 45 to 130 ° C. As a result, not only is the storage stability excellent, but also good fluidity can be exhibited during molding. It is easy to adjust the viscosity to such a value by selecting the softening point and the viscosity of the epoxy resin and the curing agent. [0030] In addition to the graphite powder, the resin binder and the epoxy resin curing accelerator, the fuel cell separator composition of the present invention also includes an internal release agent such as stearic acid and wax, and other conductive fillers. Although it is possible to mix first-class additives in a range that does not impair the effects of the present invention, these should not be calculated as a resin binder or graphite powder.
[0031] 黒鉛粉と榭脂結合剤の混合は、これらを同時に混合してもよぐ少なくとも 2種類の 粒度分布を有する黒鉛粉を事前に混合したのち、榭脂結合剤と混合してもよ ヽ。  [0031] The graphite powder and the resin binder may be mixed at the same time. The graphite powder having at least two types of particle size distribution may be mixed in advance, and then mixed with the resin binder.ヽ.
[0032] 燃料電池セパレータ組成物を使用して燃料電池セパレータを製造するには、黒鉛 粉と、エポキシ榭脂結合剤、硬化促進剤、必要により配合される添加材等カゝらなる榭 脂成分とを配合して組成物とし、これを加熱混練後、平均粒径が 100 m以下、好ま しくは 20— 50 mとなるように粉砕又は解砕し、得られた粉砕物であるコンパウンドを 100。C一 350。C、好ましくは 140。C一 230。C、より好ましくは 150。C一 200。Cで成形 、硬化することが有利である。  [0032] In order to manufacture a fuel cell separator using the fuel cell separator composition, a resin component consisting of graphite powder, an epoxy resin binder, a curing accelerator, and additives to be blended as necessary. After heating and kneading, the mixture is pulverized or crushed so that the average particle size is 100 m or less, preferably 20 to 50 m. . C-1 350. C, preferably 140. C-1 230. C, more preferably 150. C-200. It is advantageous to mold and cure in C.
[0033] 混練工程では、混練機を用いて混練する。混練機としては、汎用の-一ダー、ロー ル、単軸押出機、多軸押出機等を用いることができるが、これらに制限されるもので はない。混練は、榭脂と黒鉛粉とが可及的に均一な組成物を形成するように行う。混 練中は榭脂の粘度を低下させる目的で加熱したり、低沸点溶媒を添加したりすること もできるが、硬化を完了させないことが必要である。  In the kneading step, kneading is performed using a kneader. As the kneader, a general-purpose kneader, roll, single-screw extruder, multi-screw extruder, or the like can be used, but is not limited thereto. The kneading is performed so that the resin and the graphite powder form a composition as uniform as possible. During kneading, heating may be performed to reduce the viscosity of the resin, or a low-boiling solvent may be added, but it is necessary that curing is not completed.
[0034] 次に、混練して得られた組成物を粉砕又は解砕する。粉砕は公知の粉砕機を使用 して行うことができる。ここで使用する粉砕機としては、例えばせん断粉砕としてパル ぺライザ一、圧縮粉砕としてディスクミルなどを挙げることができる。この粉砕工程では 平均粒径の異なる黒鉛粉を使用した場合、大粒径黒鉛粉が優先的に粉砕されて、 榭脂の付着して ヽな ヽ新たな黒鉛破断面が生じるために、電気比抵抗を下げる効果 が生じる。そのため、原料として使用する平均粒径が 50— 300 mの大粒径黒鉛粉 を選択的に粉砕して 50 m以下にし、平均粒径が 50 m未満の小粒径黒鉛粉はな るべく粉砕しないようにすることが有利であり、必要以上に粉砕し過ぎると、榭脂が十 分に行き渡らなくなるため成形品の強度が低下してしまう恐れがある。  [0034] Next, the composition obtained by kneading is pulverized or crushed. The pulverization can be performed using a known pulverizer. Examples of the pulverizer used here include a pulverizer for shear pulverization and a disk mill for compression pulverization. When graphite powders with different average particle sizes are used in this pulverization process, the graphite powder with a large particle size is preferentially pulverized, resulting in the adhesion of grease and the generation of a new graphite fracture surface. This has the effect of lowering the resistance. Therefore, the graphite powder with an average particle size of 50-300 m used as a raw material is selectively pulverized to 50 m or less, and the graphite powder with an average particle size of less than 50 m is pulverized as much as possible. It is advantageous not to do so. If the pulverization is more than necessary, the resin may not be sufficiently distributed and the strength of the molded article may be reduced.
[0035] 上記のように粉砕して得られたコンパウンド (粉砕物）の 150°Cにおける粘度は、 20 0— 3000Pa's、好まし <は 2000Pa's以下、より好まし <は 1500Pa's以下、更に好ま しくは 200— 1200Pa · sとすることがよ!ヽ。かかるコンパウンドの 150°Cにおける粘度 は、使用する黒鉛やエポキシ榭脂結合剤の種類、硬化促進剤の有無、混練温度や 時間等によって変化する力 100°Cで 10分混練したのち、室温で粉砕して得たコン ノ^ンドを実施例に示す条件にて測定した値が、上記粘度を示すことが好ましい。こ の粘度は主にエポキシ榭脂と黒鉛配合量を選択することにより決定される。なお、コ ンパウンドの粘度は長期間放置することにより上昇するが、燃料電池セパレータの製 造に使用する直前において、上記粘度を示せばよい。 [0035] The viscosity at 150 ° C of the compound (crushed product) obtained by grinding as described above is 200 to 3000 Pa's, preferably <2000 Pa's or less, more preferably <1500 Pa's or less. Or 200-1200Pa · s! The viscosity at 150 ° C of such a compound is determined by the type of graphite and epoxy resin binder used, the presence or absence of a curing accelerator, the force that varies depending on the kneading temperature and time, etc. It is preferable that the value obtained by measuring the compound obtained under the conditions shown in the examples indicates the above viscosity. This viscosity is determined mainly by selecting the amounts of the epoxy resin and graphite. Although the viscosity of the compound increases when left for a long period of time, the viscosity may be indicated immediately before the compound is used for manufacturing a fuel cell separator.
[0036] 黒鉛粉とエポキシ榭脂結合剤と必要により加えられる硬化促進剤等の少量成分（ 以下、黒鉛材料以外の成分は榭脂を主とするものであるので、榭脂成分等ともいう） とを配合して、本発明の組成物とする。本発明の組成物は、黒鉛材料と榭脂成分等 からなり、榭脂成分等は少量の榭脂以外の成分を含み得る。本発明の組成物を混練 し、該混練物を 100 μ m以下、好ましく ίま 3— 50 μ m、より好ましく ίま 20— 50 μ mの 粉砕物とした後、成形することによって燃料電池セパレータが得られる。この粉砕物 は、 100°C程度の温度で混練されているため、一部硬化が進行している力 不完全 硬化物であり、これを 140°C程度以上の温度で加圧、成形し、所定時間保持すると 硬化物（成形体又はセパレータ）となる。このコンパウンドは、 150°Cにおける粘度が 200— 3000Pa'sであること力望まし!/ヽ。  [0036] A small amount of components such as graphite powder, an epoxy resin binder, and a curing accelerator added as needed (hereinafter, components other than the graphite material are mainly resin, and are also referred to as resin components, etc.) And the composition of the present invention. The composition of the present invention comprises a graphite material and a resin component, and the resin component may contain a small amount of components other than the resin. The composition of the present invention is kneaded, and the kneaded product is pulverized to 100 μm or less, preferably 3 to 50 μm, and more preferably 20 to 50 μm, and then molded to form a fuel cell separator. Is obtained. Since the pulverized material is kneaded at a temperature of about 100 ° C, it is a partially incompletely cured product in which curing is progressing, and is pressed and molded at a temperature of about 140 ° C or more. When held for a predetermined time, it becomes a cured product (molded article or separator). This compound should have a viscosity of 200-3000Pa's at 150 ° C! / ヽ.
[0037] セパレータの成形方法は、黒鉛と榭脂結合剤の配合割合にもよるが、セパレータの 穴や溝を加工した金型を使用するプレス成形やトランスファー成形、射出成形が使 用できる。プレス成形の場合は、榭脂の添加量の低い場合に適し、榭脂の添加量が 比較的多くコンパゥンドに流動性がある場合は、トランスファー成型や射出成形が好 ましい。また、熱可塑性榭脂を使用した場合は、穴溝を加工したデザインロールを用 V、た連続成形も適用できる。  [0037] The method of forming the separator depends on the mixing ratio of graphite and the resin binder, but press molding, transfer molding, and injection molding using a mold in which holes and grooves in the separator are processed can be used. In the case of press molding, transfer molding and injection molding are preferred when the amount of resin added is low and when the amount of resin added is relatively large and the compound has fluidity. When a thermoplastic resin is used, continuous forming using a design roll having a grooved hole is also applicable.
[0038] 粉砕後、金型による加熱型の成形機などを使用して成形する。この際、成形と同時 に熱硬化性榭脂であるエポキシ榭脂結合材を硬化するために、 100— 350°C、好ま しくは 140— 230°C、より好ましくは 150— 200°C程度に保持することにより行うことが よい。温度は使用する熱硬化榭脂の硬化温度以上、炭化温度未満の条件とする。成 形圧力は面方向の電気比抵抗を下げ、嵩密度を高くするためには高いほうが好まし いが、圧力を高くすると設備費用が増大するため、 20— lOOOkg/cm2程度、好ましく は 100— 800kg/cm2、より好ましくは 100— 500kg/cm2程度が適当である。 After the pulverization, molding is performed using a heating-type molding machine using a mold or the like. At this time, in order to cure the epoxy resin binder which is a thermosetting resin at the same time as molding, the temperature is set to 100 to 350 ° C, preferably 140 to 230 ° C, more preferably about 150 to 200 ° C. It is better to hold it. The temperature should be higher than the curing temperature of the thermosetting resin to be used and lower than the carbonization temperature. The molding pressure is preferably higher to reduce the electrical resistivity in the surface direction and increase the bulk density. Bur, since the equipment cost to increase the pressure increases, 20- lOOOkg / cm 2 or so, preferably 100- 800 kg / cm 2, more preferably suitably about 100- 500kg / cm 2.
これによつて、厚み 2mm、面積 700cm2程度のセパレータであれば、成形時間 20 分以内、特に 5分以内、寸法精度 100 /z m以内、特に 50 m以内で成形可能である As a result, a separator with a thickness of 2 mm and an area of about 700 cm 2 can be molded within a molding time of less than 20 minutes, especially less than 5 minutes, and a dimensional accuracy of less than 100 / zm, especially less than 50 m.
[0039] 成形の際、所定の燃料電池セパレータの形状とし、しかも所定の溝等を同時に設 ければ、それをそのまま又は簡単なカ卩ェのみで燃料電池セパレータとすることができ る。しかし、板状等に成形したのち、これに溝カ卩ェゃ孔カ卩ェをカ卩えて燃料電池セパレ ータとすることちでさる。 [0039] At the time of molding, if a predetermined shape of the fuel cell separator is formed and a predetermined groove or the like is formed at the same time, the fuel cell separator can be used as it is or with a simple casing. However, after being formed into a plate or the like, a fuel cell separator is prepared by adding a groove and a hole to the plate to form a fuel cell separator.
[0040] 本発明の製造方法で得られる燃料電池セパレータは、嵩密度が 1. 80g/cm3以上、 好ましくは 1. 85g/cm3以上とすることが可能であり、ガス不透過性、機械的強度も優 れたものとなる。嵩密度が 1. 80g/cm3未満では、ガス不透過性が劣るだけでなぐ機 械的強度も劣る。また、固有抵抗は燃料電池として機能するためには 100m Ω cm以 下、好ましくは 40m Q cm以下が求められている力 本製造方法によれば、その要求 特性を十分に達成することができる。この固有抵抗は、使用する黒鉛の種類を結晶 度の高いものとしたり、熱硬化榭脂の配合量を少なくすることにより低くすることが可 能であり、また成形圧力等によっても変化しうる。なお、固有抵抗は、後記する実施例 に記載した測定法に従うものとする。 [0040] The fuel cell separator obtained by the production method of the present invention can have a bulk density of 1.80 g / cm 3 or more, preferably 1.85 g / cm 3 or more, and is gas-impermeable and mechanical. The target strength is also excellent. When the bulk density is less than 1.80 g / cm 3 , not only gas impermeability is inferior but also mechanical strength is inferior. According to the present manufacturing method, the specific resistance is required to be 100 mΩcm or less, preferably 40 mQcm or less in order to function as a fuel cell, the required characteristics can be sufficiently achieved. This specific resistance can be lowered by increasing the type of graphite to be used with a high degree of crystallinity or by reducing the amount of the thermosetting resin, and can also be changed by molding pressure and the like. The specific resistance is determined according to the measuring method described in the examples described later.
[0041] 更に、本発明の燃料電池セパレータは、曲げ強度が 30MPa以上、気体透過率が 1  Further, the fuel cell separator of the present invention has a bending strength of 30 MPa or more and a gas permeability of 1
X 10— 14cm2以下のいずれか 1又は 2以上の特性を有することが望ましい。曲げ強度 が 30MPa未満であると、セパレータは振動や衝撃で壊れてしまう可能性が高ぐ気体 透過率が 1 X 10— 14cm2より大きくなると燃料としての水素と酸素が混じることがあり発 電効率を損なう。 It is desirable to have a X 10- 14 cm 2 or less in any one or more properties. If the bending strength is less than 30 MPa, the separator may oxygen and hydrogen as fuel if the vibration or shock can become corrupted resistance high instrument gas permeability greater than 1 X 10- 14 cm 2 is mixed power generation Impairs efficiency.
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0042] 以下、本発明を実施例に基づき具体的に説明するが、本発明はこれに限定される ものではない。この場合、成形体の固有抵抗、コンパウンド粘度、寸法精度の測定方 法は、次の通りである。 Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. In this case, the methods for measuring the specific resistance, compound viscosity, and dimensional accuracy of the molded body are as follows.
[0043] コンパゥンド粘度： 高下式フローテスター (株式会社島津製作所製、シマズフローテ スター CFT-500)を用い測定した。測定に際して用いたノズル寸法は、 φ 1 X L1とした 実際の測定は、最初に試料 (粉砕物)約 2 gを寸法 φ 10 X L7程度のタブレットに常 温で圧縮成形する。更に、あらかじめ測定温度 (150 °C)に昇温した粘度測定装置に 試料をセット後、 10 sec保持した後に、せん断速度 5000 1/sでの粘度測定を行う。 厚み精度：所定成形条件にて得た成形体の所定部位の厚みを測定し、最大値-最 小値を厚み精度とした。厚み精度の評価において、〇：50 /ζ πι未満、 Δ : 50- 100 μ m未満、 X： 100 m以上を意味する。 Compound viscosity: High-low type flow tester (Shimadzu Flote, manufactured by Shimadzu Corporation) Star CFT-500). The actual nozzle size used in the measurement was φ1 × L1. In actual measurement, about 2 g of the sample (crushed material) was first compression-molded into a tablet with a size of approximately φ10 × L7 at room temperature. Furthermore, after setting the sample in the viscosity measuring device which has been heated to the measurement temperature (150 ° C) in advance, hold it for 10 sec, measure the viscosity at a shear rate of 5000 1 / s. Thickness accuracy: The thickness of a predetermined portion of a molded body obtained under predetermined molding conditions was measured, and the maximum value-minimum value was defined as the thickness accuracy. In the evaluation of thickness accuracy, 〇: less than 50 / ζπι, Δ: less than 50-100 μm, X: 100 m or more.
固有抵抗:上記成形体について、 4端子電圧降下法により測定した。固有抵抗は、厚 さ方向（プレス成形圧力方向）と平面方向（プレス成形圧力方向に対して垂直方向） で測定を行うが、本実施例で示した固有抵抗は、セパレータ特性として特に重要視さ れる厚さ方向の値を示した。  Specific resistance: The molded product was measured by a four-terminal voltage drop method. The specific resistance is measured in the thickness direction (press forming pressure direction) and in the plane direction (perpendicular to the press forming pressure direction). The specific resistance shown in this example is particularly important as a separator characteristic. The values in the thickness direction are shown.
[0044] 使用した原料は次のとおりである。  [0044] The raw materials used are as follows.
高伝導性黒鉛:石炭系重質油を用いて、ディレードコーキング法によって製造した塊 状生コータスを、レイモンドミルにて粉砕し、平均粒径 30 mとした。これをリードノヽン マー炉で約 800°Cで炭化処理して炭化物を得た。この炭化物に炭化硼素を 5%添加 したものを 2800°Cで黒鈴ィ匕を行った。  Highly conductive graphite: Lumpy raw coats produced by delayed coking using heavy coal-based oil were pulverized with a Raymond mill to an average particle size of 30 m. This was carbonized at about 800 ° C in a lead normal furnace to obtain carbide. Kurosuzuri was performed at 2800 ° C. with 5% boron carbide added to this carbide.
[0045] オルソクレゾールノボラックのエポキシ榭脂：日本化薬株式会社製、商品名  [0045] Orthocresol novolak epoxy resin: Nippon Kayaku Co., Ltd., trade name
EOCN- 1020、融点 65°C、 150°C粘度 0.3Pa' s  EOCN-1020, melting point 65 ° C, viscosity at 150 ° C 0.3Pa's
エーテル型エポキシ樹脂:東都化成株式会社製、商品名 YSLV-80DE、融点 79°C、 150°C粘度 0.006Pa' s  Ether type epoxy resin: manufactured by Toto Kasei Co., Ltd., trade name YSLV-80DE, melting point 79 ° C, viscosity at 150 ° C 0.006 Pa's
チォエーテル型エポキシ榭脂:東都化成株式会社製、商品名 YSLV-50TE、融点 50 。C、 150°C粘度 0.006Pa' s  Thioether type epoxy resin: manufactured by Toto Kasei Co., Ltd., trade name YSLV-50TE, melting point 50. C, 150 ° C viscosity 0.006Pa's
テトラメチルビスフエノール F型エポキシ榭脂：新日鐡化学株式会社製、商品名 YSLV-80XY、融点 78、 150°C粘度 0.008Pa' s  Tetramethylbisphenol F-type epoxy resin: manufactured by Nippon Steel Chemical Co., Ltd., trade name YSLV-80XY, melting point 78, viscosity at 150 ° C 0.008 Pa's
フエノールノボラック榭脂:荒川化学工業株式会社製タマノル 758、軟ィ匕点 83°C、 150 °C粘度 0.22— 0.35Pa' s  Phenol novolak resin: Tamanol 758 manufactured by Arakawa Chemical Co., Ltd., softening point 83 ° C, 150 ° C viscosity 0.22-0.35Pa's
硬化促進剤:ジメチルゥレア系促進剤 サンァプロ株式会社製、商品名 U-CAT3502T Curing accelerator: dimethyl urea-based accelerator Sanapro Co., Ltd., trade name U-CAT3502T
実施例  Example
[0046] 実施例 1 Example 1
表 1に示したエポキシ榭脂 100重量部に、フエノールノボラック榭脂 65重量部、硬 化促進剤 1. 6重量部及び高伝導性黒鉛 495部 (黒鉛/樹脂比 = 3)を配合して組成 物とした。この組成物を、 100°Cに加熱したロールで 10分混練した。得られた混練物 をディスクミルで粉砕した。この粉砕物を金型に入れ、温度 175°C、圧力 300kg/cm2 の条件で 3分間成形し、脱型した。得られた成形体の物性を測定した。 100 parts by weight of epoxy resin shown in Table 1, 65 parts by weight of phenol novolak resin, 1.6 parts by weight of curing accelerator and 495 parts of highly conductive graphite (ratio of graphite / resin = 3) Things. This composition was kneaded with a roll heated to 100 ° C. for 10 minutes. The obtained kneaded material was pulverized with a disk mill. The pulverized product was placed in a mold, molded at a temperature of 175 ° C. and a pressure of 300 kg / cm 2 for 3 minutes, and demolded. The physical properties of the obtained molded body were measured.
粉枠物の粘度 (コンパウンド粘度)及び成形体の寸法精度と固有抵抗の測定結果 を表 1に示す。  Table 1 shows the measurement results of the viscosity (compound viscosity) of the powder frame, the dimensional accuracy of the compact, and the specific resistance.
[0047] 実施例 2— 6 Example 2-6
表 1に示す配合で、実施例 1と同様にして、粉砕物及び成形体を製造し、それぞれ 物性を測定した。結果を表 1に示す。  A pulverized product and a molded product were manufactured in the same manner as in Example 1 with the composition shown in Table 1, and the physical properties were measured. The results are shown in Table 1.
[0048] 比較例 1一 3 [0048] Comparative Examples 1 to 3
表 1に示す配合で、実施例 1と同様にして、粉砕物及び成形体を製造し、それぞれ 物性を測定した。結果を表 1に示す。  A pulverized product and a molded product were manufactured in the same manner as in Example 1 with the composition shown in Table 1, and the physical properties were measured. The results are shown in Table 1.
[0049] 実験例 1 [0049] Experimental example 1
実施例 1と同様な実験において、高伝導性黒鉛の配合量を 330部 (黒鉛/樹脂比 = 2)又は 1650部（黒鉛/樹脂比 = 10)とした他は、同様にして、粉砕物及び成形体 を製造した。  In the same experiment as in Example 1, except for changing the compounding amount of the highly conductive graphite to 330 parts (graphite / resin ratio = 2) or 1650 parts (graphite / resin ratio = 10), A molded body was manufactured.
黒鉛/樹脂比 = 2とした実験では、コンパウンド粘度： lOOPa' s以下、厚み精度：〇、 固有抵抗 48. 4m Ω cmであった。  In an experiment with a graphite / resin ratio of 2, the compound viscosity was less than 100 Pa's, the thickness accuracy was 〇, and the specific resistance was 48.4 mΩcm.
黒鉛/樹脂比 = 10とした実験では、コンパウンド粘度： 6000Pa' s以上、厚み精度： △、固有抵抗： 3. 2m Ω cmであった。  In an experiment with a graphite / resin ratio of 10, the compound viscosity was 6000 Pa's or more, the thickness accuracy was Δ, and the specific resistance was 3.2 mΩcm.
[0050] [表 1] 実施例 比較例 [0050] [Table 1] Example Comparative example
配合と物性  Formulation and physical properties
1 2 3 4 5 6 1 2 3  1 2 3 4 5 6 1 2 3
YSLV-80DE 100 100 100 100  YSLV-80DE 100 100 100 100
YSLV-50TE 100  YSLV-50TE 100
YSLV-80XY 100  YSLV-80XY 100
EOCN-1020 100 100 100 タマノル 758 65 65 65 65 63 55 54 54 54 硬化促進剤 1. 6 1. 6 1. 6 1- 6 1. 6 1. 6 1. 6 1. 6 1. 6 黒鉛 495 660 825 1155 652 620 462 616 770 黒鉛/樹脂比 3 4 5 7 4 4 3 4 5 コン Λ°ゥンド粘度  EOCN-1020 100 100 100 Tamanol 758 65 65 65 65 63 55 54 54 54 Hardening accelerator 1.6 1.6 1.61-6 1.6 1.6 1.6 1.6 1.6 Graphite 495 660 825 1155 652 620 462 616 770 Graphite / resin ratio 3 4 5 7 4 4 3 4 5
220 600 1000 3000 590 410 600 880 1500  220 600 1000 3000 590 410 600 880 1500
(Pa-s)  (Pa-s)
寸法精度 O 〇 O 〇 O o △ X X  Dimensional accuracy O 〇 O 〇 O o △ X X
固有抵抗  Specific resistance
26. 8 9. 9 6. 5 4. 8 11. 6 17. 7 26. 7 12. 1 7. 8  26.8 9.9 6.5 4.8 11.6 17.7 26.7 12.1 7.8
(mQ c m) 産業上の利用可能性  (mQ cm) Industrial applicability
本発明によれば、黒鉛と榭脂とのコンパゥンド系材料において、燃料電池セパレー タとしての要求特性、即ち電気伝導性、機械的強度などを満たしつつ、成形性をより 高めた材料を提供できる。特に、成形サイクルを短縮し、かつ寸法精度も優れ、今後 のセパレータ量産化において、対応可能なコンパウンド材料を提供できるものであり 、本分野における貢献極めて大である。本発明の製造方法で得られる燃料電池用セ ノルータは、緻密で機械的強度が高ぐ導電性に優れ、異方性が少なぐ気体透過 率が小さいので、これを燃料電池に使用したとき、効率の高い、寿命の長い燃料電 池とすることができる。  ADVANTAGE OF THE INVENTION According to this invention, in the compound type | system | group material of graphite and resin, the material which required characteristics as a fuel cell separator, ie, electrical conductivity, mechanical strength, etc., can be improved and the moldability can be further improved. In particular, it can provide a compound material that can shorten the molding cycle, has excellent dimensional accuracy, and can be used in mass production of separators in the future, and makes an extremely large contribution in this field. The fuel cell sensor router obtained by the production method of the present invention is dense, has high mechanical strength, has excellent conductivity, has low anisotropy, and has a low gas permeability. A highly efficient, long-life fuel cell can be achieved.

Claims

請求の範囲 The scope of the claims
[1] エポキシ榭脂と硬化剤からなるエポキシ榭脂結合剤と黒鉛粉とを含有する組成物 において、エポキシ榭脂結合剤に対し、黒鉛粉を重量比で 2— 10倍量配合し、該組 成物を混練及び粉砕して得られるコンパウンドの 150°Cにおける粘度が 200— 3000 Pa'sであり、燃料電池セパレータとされる成形品の電気比抵抗が固有抵抗として 100 m Ω cm以下であることを特徴とする燃料電池セパレータ用組成物。  [1] In a composition containing an epoxy resin binder comprising an epoxy resin and a curing agent and graphite powder, 2 to 10 times the weight ratio of graphite powder to the epoxy resin binder is blended. The compound obtained by kneading and pulverizing the composition has a viscosity at 150 ° C of 200 to 3000 Pa's, and the electrical resistivity of the molded product used as the fuel cell separator is 100 mΩcm or less as the specific resistance. A composition for a fuel cell separator, comprising:
[2] エポキシ榭脂結合剤に対し、黒鉛粉を重量比で 3— 7倍量配合し、燃料電池セパレ ータとされる成形品の電気比抵抗が固有抵抗として 40m Ω cm以下である請求項 1記 載の燃料電池セパレータ用組成物。  [2] A claim that the powdered graphite powder is mixed with the epoxy resin binder in an amount of 3-7 times by weight, and the electrical resistivity of the molded article used as a fuel cell separator is 40 mΩcm or less as a specific resistance. Item 8. The composition for a fuel cell separator according to Item 1.
[3] エポキシ榭脂が、 150°Cにおける粘度 1一 20mPa's、融点 45— 130°C、常温で固 体である結晶性エポキシ榭脂を 1種以上含むことを特徴とする請求項 1記載燃料電 池セパレータ用組成物。  [3] The fuel according to claim 1, wherein the epoxy resin contains at least one kind of crystalline epoxy resin which is a solid at room temperature at a viscosity of 120 mPa's at 150 ° C and a melting point of 45 to 130 ° C. Composition for battery separator.
[4] エポキシ榭脂と硬化剤からなるエポキシ榭脂結合剤に対し、黒鉛粉を重量比で 2— 10倍量配合した黒鉛粉とエポキシ榭脂結合剤を含有する組成物にぉ ヽて、ェポキ シ榭脂として 150°Cにおける粘度 1一 20mPa's、融点 45— 130°C、常温で固体であ る結晶性エポキシ榭脂を 1種以上含むことを特徴とする燃料電池セパレータ用組成 物。  [4] A composition containing graphite powder and an epoxy resin binder obtained by mixing graphite powder in an amount of 2 to 10 times by weight with respect to an epoxy resin binder comprising an epoxy resin and a curing agent, A composition for a fuel cell separator comprising, as an epoxy resin, at least one kind of crystalline epoxy resin which has a viscosity of 120 mPa's at 150 ° C, a melting point of 45 to 130 ° C, and is solid at room temperature.
[5] エポキシ榭脂結合剤に対する黒鉛粉の配合量が、重量比で 3— 7倍量である請求 項 4に記載の燃料電池セパレータ用組成物。  5. The composition for a fuel cell separator according to claim 4, wherein the compounding amount of the graphite powder with respect to the epoxy resin binder is 3 to 7 times by weight.
[6] 結晶性エポキシ榭脂が、下記一般式（1) [6] The crystalline epoxy resin has the following general formula (1)
[化 1]  [Chemical 1]
Figure imgf000017_0001
Figure imgf000017_0001
(但し、 Gはダルシジル基を示し、 Rは 1価の基を示し、 nは 0— 4の整数を示し、 Xは S 又は 0を示す)で表されるエポキシ榭脂である請求項 1又は 4に記載の燃料電池セパ レータ用組成物。 Wherein G represents a darcidyl group, R represents a monovalent group, n represents an integer of 0-4, and X represents S or 0. Fuel cell separator described in 4 A composition for a lator.
[7] 請求項 1又は 4に記載の組成物を、混練し、粉砕した後、該粉砕物を温度 140— 2 [7] After kneading and pulverizing the composition according to claim 1 or 4, the pulverized product is heated to a temperature of 140-2.
30°Cで成形、硬化することを特徴とする燃料電池セパレータの製造方法。 A method for producing a fuel cell separator, comprising molding and curing at 30 ° C.
[8] 請求項 7記載の燃料電池セパレータの製造方法で得られた燃料電池セパレータ。 [8] A fuel cell separator obtained by the method for producing a fuel cell separator according to claim 7.
PCT/JP2004/019031 2003-12-26 2004-12-20 Composition for fuel cell separator and process for producing fuel cell separator WO2005064721A1 (en)

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