ES2385322T3 - Composition of curable resin conductor and separator for fuel cell - Google Patents

Abstract

A curable conductive resin composition characterized in that it comprises (A) a curable resin composition and (B) a carbon material, with a weight ratio of component (A) to component (B) of 70-5: 30-95, characterized in that the curable resin composition of component (A) comprises (A1) an elastomer with a Mooney viscosity (MN1 + 4 (100 ° C)) of 25 or greater in a proportion of 60-10% by weight, (A2) a resin reactive radical in a proportion of 40-90% by weight, the total components (A1) and (A2) being 100% by weight, and (A3) an organic peroxide in a proportion of 0.2-10 parts by weight for 100 parts by weight of (A1 + A2), wherein the reactive radical resin is one or more selected (s) from unsaturated polyester resins, vinyl ester resins, allyl ester resins, urethane resins, resins diallyl phthalate and 1,2-polybutadiene resins.

Description

Composition of curable resin conductor and separator for fuel cell.

Technical Field

The present invention relates to a curable conductive resin composition with excellent conductivity and heat release properties, and particularly relates to a fuel cell separator, a battery assembly, an electrode or a heat release plate, Already a process for its production.

Previous Technique

Conventionally, metals and carbon materials have been used for purposes that require high conductivity. Carbon materials, in particular, being corrosion-free materials that are characteristic of metals and exhibiting excellent thermal resistance, lubricating properties, heat conductivity and durability, have come to play an important role in fields such as electronics, electrochemistry, energy, transport vehicles and the like. Composite materials made of combinations of carbon materials and polymeric materials have also reached spectacular levels of development, and have come to be used for their continuously increasing capacity for efficiency and functionality. The greater freedom in forming processability allowed by combinations with polymeric materials in particular has been a reason for the increased development of carbon materials in fields that require conductivity.

In recent years, in view of the problems related to the environment and energy, more attention has been given to clean electric generators in which fuel cells generate electricity by the inverse reaction to water electrolysis, using hydrogen and oxygen, and that produce no waste other than water, and carbon and polymer materials also play an important role for them. Polymer solid fuel cells seem extremely promising for use in cars and personal use when the purpose is use at low temperatures. Such fuel cells can exhibit high power electricity generation by stratification of individual batteries that are composed of a solid polymer electrolyte, gas diffusion electrodes, a catalyst and a separator.

The separators used to distribute the individual batteries usually have grooves for supplying the combustible gas and the oxidizing gas, and must have high gas impermeability to achieve complete separation thereof, as well as high conductivity to reduce internal resistance. Other requirements include thermal conductivity, durability and robustness.

In order to meet these requirements, such separators have traditionally been evaluated from the point of view of both metals and carbon materials. The corrosion problem associated with metals has caused attempts to coat surfaces with precious metals or carbon, but it has not been possible to achieve adequate durability, and coating costs have also been a problem.

On the other hand, carbon materials have also been studied extensively, examples of which include molded articles obtained by pressure molding of expanded graphite sheets, molded articles obtained by impregnating a sintered carbon material with a resin and curing, and molded articles obtained by mixing and molding thermosetting resin-calcined vitreous carbon, carbon powder and a resin.

For example, in Japanese Unexamined Patent Publication (Kokai) HEI No. 8-222.241 a complex process is described in which a binder material is added to a carbonaceous powder in order to ensure reliability and dimensional accuracy, and the mixture is Heats and conforms to CIP, after which it is calcined and graphitized to produce an isotropic graphite material that is then impregnated with a thermosetting resin, subjected to curing treatment, and carved with grooves by a cutting step . Likewise, Japanese Unexamined Patent Publication SHO No. 60-161144 describes the impregnation of a thermosetting resin on paper comprising carbon powder or carbon fiber, followed by paper stratification, pressing of the laminate and calcining thereof. Japanese Unexamined Patent Publication No. 2001-68128 describes the injection molding of a phenolic resin in a matrix formed with separators and calcination thereof. Such calcined materials exhibit high electrical conductivity, but the long time required for calcination reduces productivity. When a cutting step is necessary, productivity is further reduced and costs increase, so that numerous problems have prevented its future use as common materials.

On the other hand, molding methods have been considered as means to increase productivity and reduce costs, and the materials used for this purpose have generally been materials composed of carbon-based fillers and resins. For example, Japanese Unexamined Patent Publication SHO No. 58-53167, Japanese Unexamined Patent Publication SHO No. 60-37670, Japanese Unexamined Patent Publication SHO No. 60-246568, Japanese Patent Publication Examined (Kokoku) SHO No. 64-340 and the Japanese Examined Patent Publication HEI No. 6-22136 each describe a separator made of a thermosetting resin such as a phenolic resin, graphite or carbon, the SHO Examined Japanese Patent Publication No. 57-42157 describes a bipolar separator made of a thermosetting resin such as an epoxy resin and an electroconductive material such as graphite, and Japanese Unexamined Patent Publication Publication HEI No. 1-311570 describes a separator comprising a mixture of graphite expanded and carbon black with a thermosetting resin such as a phenolic resin or furan resin.

Separators that use composite materials of a carbon-based filler and a resin require a drastically higher content of the carbon-based filler to exhibit high conductivity, but because it is necessary to add a large amount of resin to maintain formability, it has been difficult to achieve conductivity high enough. An attempt has also been made to form the composition on a high precision sheet by rollers or similar means and to harden it into a form of fuel cell separator, in order to improve the thickness accuracy which is a particularly important feature for battery cell separators. fuel, but since the resulting sheet is not uniform when it contains a high proportion of carbon-based loading, it has been necessary to increase the amount of resin that serves as the matrix. As a result, it has not been possible to achieve adequate electrical conductivity and thermal conductivity.

When, for greater electrical conductivity, a calcination step is included in which the molded article is heated for a long period of time at an elevated temperature of 1000-3000 ° C, the time required for production is lengthened and the process of Production becomes complicated, further increasing costs.

It is an object of the present invention, which has been completed in view of these circumstances, to provide a curable conductive resin composition capable of loading a high conductive load content and with excellent conformability processability. It is another object thereof to provide a fuel cell separator, an assembly for a battery, an electrode or a heat release plate with excellent conductivity and heat release properties, which is obtained by forming the composition mentioned above in a sheet while it is still uncured, and curing it in a form of fuel cell separator, an assembly for a battery, an electrode or a heat release plate, as well as a process for its production.

Description of the Invention

In view of these circumstances, the authors of the present invention have diligently dedicated their efforts to the development of a curable resin conductive composition composed primarily of a carbon-based filler and a curable resin composition, in which the cured product exhibited conductivity excellent and superior heat release properties and, by adding a high molecular weight elastomer to a curable resin composition, have achieved success in the development of a curable conductive resin composition that allows a high packing content of a load based in carbon, which exhibits excellent conformability processability and can be shaped into a uniform sheet while still in an uncured state, as well as an uncured sheet prepared from the composition. The inventors have completed it as a highly conductive fuel cell separator, an assembly for a battery, an electrode

or a heat release plate with excellent precision of thin film thickness, and a process for its production, by combining a specific carbon material containing boron with the curable resin composition mentioned above.

Said another way, the invention designed to achieve the above-mentioned object relates to a curable conductive resin composition according to [1] to [20] below, an uncured sheet prepared therefrom, a fuel cell separator , an assembly for a battery, an electrode or a heat release plate that uses it and a process for its production.

[1] A curable conductive resin composition characterized in that it comprises (A) a curable resin composition comprising an elastomer with a Mooney viscosity (ML1 + 4 (100 ° C)) of 25 or greater in a proportion of 2-80% by weight and (B) a carbon material, with a weight ratio of component (A) to component (B) of 705: 30-95.

[2] The curable conductive resin composition according to [1], characterized in that the curable resin composition of component (A) comprises (A1) an elastomer with a Mooney viscosity (ML1 + 4 (100 ° C)) of 25 or greater in a proportion of 60-10% by weight, (A2) a reactive radical resin in a proportion of 40-90% by weight, the total components (A1) and (A2) being 100% by weight, and (A3) an organic peroxide in a proportion of 0.2-10 parts by weight for 100 parts by weight of (A1 + A2).

[3] The curable conductive resin composition according to [2], characterized in that the elastomer of component (A1) is one or a combination of two or more selected from the group consisting of acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, rubber styrene-butadiene, ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, ethylene-butadiene rubber, fluorinated rubber, isoprene rubber, silicone rubber, acrylic rubber and butadiene rubber.

[4] The curable conductive resin composition according to [3], wherein the elastomer of component (A1) is one or a combination of two or more selected from the group consisting of acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, rubber styrene-butadiene, ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, and butadiene rubber.

[5] The curable conductive resin composition according to any one of [1] to [4], characterized in that the carbon material of component (B) is one or a combination of two or more selected from the group consisting of powder of graphite, artificial graphite powder, natural graphite powder, expanded graphite powder, carbon fiber, carbon fiber produced in the vapor phase with a diameter of 0.05-10 μm and a length of 1-500 μm, carbon nanotubes with a fiber diameter of 0.5-100 nm and a fiber length of 0.01-10 μm, and carbon black.

[6] The curable conductive resin composition according to [5], wherein the graphite powder is graphite powder with an average particle size of 0.1-150 μm and a crosslink spacing (Co value) of 6.745 Å or less.

[7] The curable conductive resin composition according to any one of [1] to [6], characterized in that when the carbon material of component (B) is pressurized to an apparent density of 1.5 g / cm3, the Electrical resistivity of the powder in the direction perpendicular to the pressurization direction is not greater than 0.07 Ωcm.

[8] The curable conductive resin composition according to any one of [1] to [7], characterized in that the carbon material of component (B) contains boron in a proportion of 0.05-10% by weight.

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

[10] A process for producing an uncured sheet, characterized in that the curable conductive resin composition according to any one of [1] to [9] is formed while in the uncured state, using a type of forming machine such as an extruder, roller and calender.

[11] An uncured sheet produced by the process according to [10].

[12] An uncured sheet according to [10] having a thickness of 0.5-3 mm and a width of 20-3000 mm.

[13] A process for producing a cured and grooved sheet, characterized in that the uncured sheet according to

[11] or [12] is cut or stamped, and the sheet is supplied to a die and cured hot with a compression molding machine.

[14] A fuel cell separator known by the method described in [13] that uses a die grooved on one side or on both sides.

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

[16] A fuel cell separator comprising a cured sheet obtained by supplying the curable conductive resin composition according to any one of [1] to [9] or the uncured sheet according to [11] or

[12] to a die grooved on both sides and curing it with a compression molding machine, the fuel cell separator being characterized as having a volume resistivity of no more than 2 x 10-2 Ωcm, a resistance of contact not greater than 2 x 10-2 Ωcm2, a thermal conductivity of at least 1.0 W / mK and a permeability of 1 x 10-6 cm² / s, and containing at least 0.1 ppm of boron.

[17] A fuel cell separator, an assembly for a battery, an electrode or a heat release plate characterized by being a cured and grooved conductive resin sheet comprising (A) a curable resin composition comprising an elastomer in a proportion of 2-80% by weight based on the weight of the curable resin composition and (B) a carbon material, with a weight ratio of component (A) of component (B) of 70-5: 30 -95.

[18] The fuel cell separator, an assembly for a battery, an electrode or a heat release plate, in accordance with [17], characterized in that the elastomer (A1) of the component (A) is one or a combination from two or more selected from the group consisting of acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, ethylenebutadiene rubber, fluorinated rubber, isoprene rubber, silicone rubber , acrylic rubber and butadiene rubber.

[19] The fuel cell separator, an assembly for a battery, an electrode or a heat release plate according to [17] or [18], wherein the component (A) comprises the elastomer in a proportion of 80-2% by weight and a reactive radical resin in a proportion of 20-98% by weight.

[20] The fuel cell separator according to any one of [17] to [19], characterized by having a volume resistivity no greater than 2 x 10-2 Ωcm, a contact resistance no greater than 2 x 10 -2 Ωcm2, a thermal conductivity of at least 1.0 W / mK and a permeability of not more than 1 x 10-6 cm2 / s, and containing at least 0.1 ppm of boron.

Brief Description of the Drawings

Fig. 1 is an illustration showing a method of measuring the electrical resistivity of graphite powder.

Fig. 2 is an illustration showing a method of calculating the electrical resistivity of graphite powder.

Fig. 3 shows a sheet cured and grooved on both sides.

Fig. 4 is an illustration showing a method of measuring the contact resistance of a cured product.

Optimal Mode for Carrying Out the Invention

The present invention will be explained in more detail below.

The elastomer (A1) in the curable resin composition of component (A) according to the invention is one or a combination of two or more selected from acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene rubber -propylene, ethylene-propylene-diene terpolymer rubber, ethylenebutadiene rubber, fluorinated rubber, isoprene rubber, silicone rubber, acrylic rubber, butadiene rubber, high styrene rubber, chloroprene rubber, urethane rubber, special rubber based in polyether, tetrafluoroethylene-propylene rubber, epichlorohydrin rubber, norbornano rubber and butyl rubber.

Of these, acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrenebutadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, ethylene-butadiene rubber, butadiene rubber, fluorinated rubber, high styrene rubber are especially preferred , special rubber based on polyether and epichlorohydrin rubber from the point of view of durability, water resistance and ease of work, with acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, rubber being especially preferred ethylene-propylene-diene terpolymer and butadiene rubber.

The elastomer (A1) in the curable resin composition of component (A) according to the invention has a Mooney viscosity (ML1 + 4 (100 ° C)) of 25 or greater, preferably 40 or greater and more preferably 50 or greater . If the Mooney viscosity (ML1 + 4 (100 ° C)) is less than 25, the loading capacity of the carbon material load is poor, thus hindering the continuous conformation of a uniform uncured sheet when the material load is Carbon is filled to a high content. Mooney viscosity can be measured according to JIS K6300, using a Mooney AM-1 viscosity measuring device (product of Toyo Seiki Seisakusho, Ltd.). M in ML1 + 4 is Mooney viscosity, L indicates a rotor type L, 1 + 4 indicates 1 minute of preheating and 4 min of rotor operation, and (100 ° C) indicates a test temperature of 100 ° C.

The reactive radical resin (A2) in the curable resin composition of component (A) according to the invention is one or more selected from unsaturated polyester resins, vinyl ester resins, allyl ester resins, urethane resins. acrylate, alkyd resins, diallyl phthalate resins, and 1,2-polybutadiene resins.

In the fields that require thermal resistance, resistance to acids and the like, a resin having a ring structure such as a homocyclic or heterocyclic ring is preferred in the molecular skeleton. For example, resins such as unsaturated polyester or vinyl ester resins containing bisphenol, novolac-type vinyl ester resins, allyl ester resins, and diallyl phthalate resins are preferred, since they can improve strength Thermal, chemical resistance and resistance to hot water.

1,2-Polybutadiene resins are preferable from the standpoint of thermal resistance, chemical resistance, and resistance to hot water, since they do not contain double bonds in the main chains.

In accordance with the invention, the component used as the curable resin composition of component (A) may also contain, in addition to the components (A1) and (A2) mentioned above, a reactive radical monomer containing a double unsaturated bond such as a vinyl or allyl group, for the purpose of controlling the reaction rate, adjusting the viscosity, improving the cross-linking density, adding more functionality, and the like. As examples there may be mentioned esters of unsaturated fatty acids, vinyl aromatic compounds, vinyl esters of saturated fatty acids or carboxylic aromatic acids and their derivatives and crosslinkable polyfunctional monomers.

Esters of unsaturated fatty acids include (meth) alkyl acrylates such as (meth) methyl acrylate, (meth) ethyl acrylate, (meth) butyl acrylate, (2) ethylhexyl (meth) acrylate, (meth) octyl acrylate , (meth) dodecyl acrylate, (meth) octadecyl acrylate, (meth) cyclohexyl acrylate and methylcyclohexyl (meth) acrylate; aromatic esters of acrylic acid such as (meth) phenyl acrylate, (meth) benzyl acrylate, (meth) 1-naphthyl acrylate, (meth) fluorophenyl acrylate, (meth) chlorophenyl acrylate, (meth) cyanophenyl acrylate , (meth) methoxyphenyl acrylate and biphenyl (meth) acrylate; haloalkyl (meth) acrylates such as fluoromethyl (meth) acrylate and chloromethyl (meth) acrylate; (meth) glycidyl acrylates, alkylamino methacrylates and esters of α-cyanoacrylic acid.

As the vinyl aromatic compounds there may be mentioned styrene, α-methylstyrene, chlorostyrene, styrene sulfonic acid, 4-hydroxystyrene and vinyl toluene.

Vinyl esters of saturated fatty acids or carboxylic aromatic acids and their derivatives include vinyl acetate, vinyl propionate and vinyl benzoate.

As the polyfunctional crosslinkable monomers can be mentioned di (meth) acrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, di (meth) tetraethylene glycol acrylate, di (meth ) tripropylene glycol acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,5-pentadiol di (meth) acrylate, 1,6 (meth) acrylate -hexadiol, neopentyl glycol di (meth) acrylate, oligoester di (meth) acrylates, polybutadiene di (meth) acrylate, 2,2-bis (4- (meth) acryloxyphenyl) propane and 2,2-bis (4- m (meth) acryloyloxypipethoxy) phenyl) propane; Aromatic diallyl carboxylates such as diallyl phthalate, diallyl isophthalate, dimethanyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylate, diallyl 1,5-naphthalenedicarboxylate, and 4,4'-xylenedicarboxylate diallyl diphenyl dicarboxylate; crosslinkable difunctional monomers such as diallyl cyclohexanedicarboxylate and divinylbenzene; crosslinkable trifunctional monomers such as tri (meth) trimethylolethane acrylate, tri (meth) trimethylolpropane acrylate, tri (meth) pentaerythritol acrylate, tri (meth) allyl isocyanurate, tri (meth) allyl cyanurate, triallyl trichloate and chloratete diallyl; and crosslinkable tetrafunctional monomers such as pentaerythritol tetra (meth) acrylate.

The addition of crosslinkable polyfunctional monomers is preferred for improved thermal resistance and hot water resistance.

The organic peroxide (A3) used in the curable resin composition of component (A) according to the invention can be any publicly known one such as a dialkyl peroxide, acyl peroxide, hydroperoxide, ketone peroxide, peroxy ester or the like. Mention may be made of benzoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanate, 1,1,3,3-tetramethylbutyl, 1,1-bis (t-butylperoxy) -3,3 peroxy-2-ethylhexanate, 5-Trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (4,4-dibutylperoxycyclohexyl) propane, t-butyl peroxy-2-ethylhexanate, t-butyl peroxy-2-ethylhexanate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl2,5-di (benzoylperoxy) hexane, t-butyl peroxybenzoate, t-butyl cumum peroxide, p-menthane hydroperoxide, t-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-dibutylperoxyhexino-3 and the like.

Those among the above mentioned that have a decomposition temperature of 90 ° C to 190 ° C and an activation energy of 30 Kcal / mol or greater are preferred from the point of view of the product forming cycle as well as in terms of robustness and durability. Preferred examples include 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-di (t-butylperoxy) -hexane, 2,5 -dimethyl-2,1-di (benzoylperoxy) hexane, t-butyl peroxybenzoate, t-butylcumyl peroxide, p-menthane hydroperoxide, t-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, di-t peroxide -butyl and 2,5-dimethyl-2,5-dibutylperoxyhexino-3.

The ratios by weight of the elastomer (A1) and the reactive radical resin (A2) of the curable resin composition are 6010% by weight of the elastomer and 40-90% by weight of the reactive radical resin (A1 + A2 = 100% in weight).

The organic peroxide (A3) in the curable resin composition is added to 0.2-10 parts by weight for 100 parts by weight of the (elastomer (A1) + reactive radical resin (A2)). It is more preferably added in a proportion of 0.5-8 by weight and even more preferably 0.8-6 parts by weight. If the amount of organic peroxide (A3) exceeds 10 parts by weight, the decomposition of organic peroxide leads to an increased generation of gas, often causing reduced product tightness. For less than 0.2 parts by weight, the cross-linking density of the product is reduced, thereby decreasing robustness and often also deteriorating durability.

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

The graphite powder is preferably fine graphite powder with an average particle size of 0.1-150 μm, more preferred between 5 and 80 μm and a reticule spacing (Co value) of 6.745 Å or less. The graphite powder preferably contains boron.

A fine graphite powder containing boron with an average particle size of 5-80 μm and a right spacing (Co value) of 6.745 Å or less can be obtained by adding a boron compound during graphing in order to increase conductivity and the loading capacity / resin ratio of graphite powder.

When boron is not added, the degree of graffiti (crystallization) is lower and the interstitial space (referred to here as "Co value") increases, which makes it impossible to obtain a graphite powder with suitably high conductivity.

The method of adding boron is not restricted as long as the boron and / or boron compound is mixed in the graphite, but preferably the boron is present between the layers of graphite crystals, or a portion of the carbon atoms of Graphite crystals are replaced with boron atoms. The bonds between boron atoms and carbon atoms, when a portion of the carbon atoms are replaced by boron atoms, can be any type of bond such as covalent bonds or ionic bonds.

In order to obtain graphite powder, coke is usually produced first. The starting area for coke can be petroleum based pitch, coal based pitch or the like. Said starting materials are carbonized to produce coke.

The graffiti powder is generally obtained from coke by a method of spraying the coke before the graffiti treatment, a method of graffiti of the coke itself before spraying, or a method of adding a binder to the coke and molding and calcining thereof to obtain a calcined product (referring to both coke and calcined product as coke) which is then graphitized and sprayed to obtain a powder. According to the invention, the method of coke spraying is preferably used before graphitization. Since the coke starting material should preferably have a degree of crystallization as low as possible, a coke starting material under heat treatment at no more than 2000 ° C and preferably no more than 1200 ° C is preferred.

It has been found that coking powder graphitization not only promotes crystallization but also reduces the specific surface area of the particles and it is therefore also convenient that said point of view.

For example, a coke powder with an average particle size of 10 μm obtained by coke spraying has a specific surface area of approximately 14 m² / gram, but after graffiti at 2800 ° C or greater, the specific surface area is reduced to 2-3 m² / g. However, when spraying is done after graffiti, this value is at least 5 m² / g and in some cases 10 m² / g or greater, depending on the particle size. In contrast, in the graffiti method after spraying, the carbon atoms are presumably rearranged and a portion of the surface is volatilized at high temperature during graffiti, thereby cleaning or smoothing the surface and reducing the specific surface.

A high speed rotary sprayer (hammer mill, spindle mill or cage mill) or any of several types of ball mills (drum mill, oscillating mill or planetary mill), agitator mills can be used for spraying the coke. (bead mill, attrition mill, channel mill or annular mill), or the like. Fine spray machines may also be used, such as a sieve mill, turbulence mill, supermicrometer mill, jet mill, with appropriate selection of conditions. The sprayer is used to spray the coke, with appropriate selection of the spray conditions and with powder classification if necessary, up to an average particle size preferably in the range of 0.1-150 μm. More preferably, particles with a size less than 0.1 μm and / or greater than 150 μm are essentially separated, leaving less than 5% by weight or less and preferably 1% by weight or less of such particles.

Preferably, the graphite powder of this invention preferably contains boron and the granularity of the graphite powder, in terms of average particle size, is preferably 0.1-150 μm, more preferably 1-100 μm, and more preferably still 5 -80 μm The particle size was measured by the laser diffraction dispersion method. Specifically, a 50 mg sample was passed, 50 ml of distilled water was added, 0.2 ml of a 2% aqueous solution of Triton (surfactant) was subsequently added, the mixture was subjected to ultrasonic diffusion for 3 min and The measurement was then performed with a Microtrack HRA device manufactured by Nikkiso Corp.

The method of classification of coke powder can be any one that allows separation, and for example, separation with sieves or an air classifier can be used as a centrifugal forced turbulence classifier (micrometric separator, Turboplex, turboclassifier or super separator) or a classifier inertial (improved virtual impactor or elbow jet). A wet phase precipitation separation method or a centrifugal classification method can also be used.

The graphite powder according to the invention can also be obtained by the addition of elementary B or H3BO3, B2O3, B4C, BN or the like as the boron source to a powder such as coke prior to the graphitizing treatment, and thorough mixing for graphitization. In the case of a non-uniform mixture of the boron compound with the carbon material, not only is the graphite powder non-uniform, but the sintering passivity of the graphite powder during graphitization also increases. For a uniform mixture, the boron source is preferably mixed with the powder such as a coke, after preparation in powder form with a particle size not greater than 50 μm and preferably not greater than approximately 20 μm.

A higher graphitization temperature is preferred for dust such as coke powder containing the boron source, but due to restrictions on the apparatus, etc., it is preferably maintained in the range of 2500-3200 ° C. The graffiti method used can be a method that uses an Atchison oven, in which the powder is placed in a graphite vessel and is subjected to direct electrification, or a method in which the powder is heated with a graphite heating unit .

The graphite powder of the invention is preferably one having high crystallinity, while the Co value of the graphite structure comprising stacked hexagonal lattice layers is preferably not more than 6.745Å, more preferably not greater than 6.730 Å and of even more preferable mode not greater than 6,720 Å. The increase in the crystallinity of the graphite powder allows the electrical resistance of the cured product to be reduced.

An expanded graphite powder can be obtained, for example, by immersion of graphite that has reached a highly crystalline structure, such as natural graphite or pyrolytic graphite, in a strongly oxidizing solution such as a mixed solution of concentrated sulfuric acid and nitric acid or a mixture of concentrated sulfuric acid and hydrogen peroxide to produce an interlaminar graphite compound, water wash, and rapid heating for expansion in the direction of the C axis of the graphite crystals, this powder can also be laminated into a sheet and finally pulverized.

The carbon fiber may be a pitch-based fiber produced from heavy crude oil, a petroleum by-product, coal tar or the like, or a PAN-based fiber, produced from polyacrylonitrile.

Carbon fiber produced in the vapor phase is obtained, for example, using an organic compound such as benzene, toluene or natural gas as the starting material for thermal decomposition reaction with hydrogen gas at a temperature of 800-1300 ° C in the presence of a transition metal catalyst such as ferrocene. It is then preferably subjected to a graffiti treatment at approximately 25003200 ° C. More preferably, it is subjected to graffiti treatment at about 2500-3200 ° C with a graffiti catalyst such as boron, boron carbide, beryllium, aluminum or silicon.

According to the invention, the carbon fiber produced in the vapor phase preferably has a fiber diameter of 0.05-10 μm and a fiber length of 1-500 μm, more preferably having a fiber diameter of 0.1- 5 μm and a fiber length of 5-50 μm, and even more preferably having a fiber diameter of 0.1-0.5 μm and a fiber length of 10-20 μm.

Carbon nanotubes have been a focus of the industry in recent years not only because of their mechanical resistance but also because of their electric field emitting function and their hydrogen occlusion properties, and they have begun to receive attention for their magnetic function. Such carbon nanotubes are known as graphite whiskers, filamentous carbon, graphite fibers, ultrafine carbon tubes, carbon tubes, carbon fibrils, carbon microtubes and carbon nanofibers. Carbon nanotubes include monolayer carbon nanotubes comprising a single graphite film that forms the tubes, and multilayer carbon nanotubes comprising graphite multi-films. Any of these types can be used according to the invention, but monolayer carbon nanotubes are preferred, since they can be used to obtain cured products with greater conductivity and mechanical strength.

Carbon nanotubes can be manufactured, for example, by the arc discharge method, laser vapor deposition method or thermal decomposition method as described in "Carbon Nanotube Basics", Corona Publications (pp. 23-57, 1998), and can be purified by hydrothermal methods, centrifugal separation, ultrafiltration or oxidation in order to increase purity. High temperature heating in an inert gas atmosphere at about 2500-3200 ° C is more preferred to remove impurities. Even more preferred is heating at an elevated temperature in an inert gas atmosphere at about 25003200 ° C together with a graffiti catalyst such as boron, boron carbide, beryllium, aluminum, silicon or the like.

According to the invention, the carbon nanotubes used preferably have a fiber diameter of 0.5100 nm and a fiber length of 0.01-10 μm, more preferably a fiber diameter of 1-10 nm and a length of fiber of 0.05-5 μm, and even more preferably a fiber diameter of 1-5 nm and a fiber length of 0.1-3 μm.

The fiber size and fiber length of the carbon fibers produced in the vapor phase and the carbon nanotubes according to the invention can be measured with an electron microscope.

As carbon black can be mentioned Ketchen black or acetylene black obtained by incomplete combustion of natural gas or the like or thermal decomposition of acetylene, furnace carbon obtained by incomplete combustion of hydrocarbon oils or natural gas, and thermal carbon obtained by thermal decomposition of natural gas.

The carbon material of component (B) according to the invention, when it has an apparent density of 1.5 g / cm 3, preferably has a low electrical resistivity of the powder in the direction perpendicular to the pressurization direction, and preferably the same is not greater than 0.07 Ωcm and more preferably not greater than 0.01 Ωcm. An electrical resistivity of the carbon material greater than 0.07 Ωcm results in lower conductivity of the cured product obtained by curing the composition which also comprises the curable resin, making it impossible to obtain the desired cured product.

A method of measuring the electrical resistivity of graphite powder is illustrated in Fig. 1 and Fig. 2. In Fig. 1, 1 and 1 'are, respectively, electrodes (+) and (-) made of copper plates, 2 is a compression bar made of resin, while 3 is a pedestal and 4 is a side frame, both made of resin, 5 is a sample of graphite powder, and 6 is a set of voltage measurement terminals arranged under the sample and in the center of the sample in the direction perpendicular to the surface of the drawing page.

The electrical resistivity of the sample is measured as follows, using the four-terminal method illustrated in Fig. 1 and Fig. 2. The sample is compressed with compression bar 2. A current (I) is flowed to the electrode (-) 1 'from the electrode (+) 1. The voltage (V) between terminals 6 is measured. In this case, the voltage is the measured value when the sample is pressed by the compression rod to an apparent density of 1.5 g / cm3. If the electrical resistance of the sample (between the terminals) is R (Ω), then R = V / I. From this it is possible to determine the electrical resistivity by ρ = R · S / L (ρ: electrical resistivity, S = cross-sectional area (cm3) in the electrification direction of the sample, that is the direction perpendicular to the compression direction, and L is the distance between terminals 6 (cm)). For the actual measurement, the sample has a perpendicular cross section with a width of approximately 1 cm, a length (height) of 0.5-1 cm and a length in the direction of electrification of 4 cm, and the distance (L) between the terminals is 1 cm.

Boron, when contained in the carbon material of component (B) according to the invention, is preferably present in a proportion of 0.05-10% by weight in the carbon material. If the boron content is less than 0.05% by weight, it may not be possible to obtain a graphite powder with the desired high conductivity. A boron content greater than 10% by weight is not preferred because no additional effect of improved conductivity of the carbon material can be expected.

As for the method of adding boron, a fine graphite powder containing boron of the invention can be used alone, or it can be added by mixing with another carbon material. Alternatively, elementary B, or B4C, BN, B2O3, H3BO3 or the like can be added as the source of boron to artificial graphite, natural graphite, carbon fiber, carbon fiber produced in vapor phase (VGCF), carbon nanotubes (CNT ) or the like, either alone or in admixture, and the mixture is thoroughly mixed and subjected to graffiti treatment at approximately 2500-3200 ° C.

The curable resin composition (A) and the carbon material (B) of the invention are present in a weight ratio of 70-5: 30-95. If the amount of component (A) added exceeds 70% by weight and the amount of carbon material (B) is less than 30% by weight, the conductivity of the cured product is reduced. The ratio of component (A) and component (B) is more preferably 45-5: 55-95, and more preferably even 20-10: 80-90.

The curable conductive resin composition of the invention may also contain additives such as glass fibers, inorganic fiber fillers, organic fibers, ultraviolet stabilizers, antioxidants, antifoaming agents, leveling agents, release agents, lubricants, water repellents, thickeners. , low shrinkage agents, hydrophilic improvers, crosslinking aids, etc. for the purpose of improving hardness, robustness, conductivity, formability, durability, weather resistance, water resistance and the like.

In order to obtain a curable conductive resin composition according to the invention, the above-mentioned components are mixed to maximum uniformity using a mixing machine or a kneader commonly used in the field of resins, such as a roller, extruder , kneader, Banbury mixer, Henschel mixer, planetary mixer or the like, while maintaining at a temperature at which the mixture does not begin to harden. When an organic peroxide is to be added, all of the remaining components can be mixed first uniformly and finally the organic peroxide added.

The curable conductive resin composition obtained is formed only once using an extruder, roller, calender or the like on a sheet of prescribed thickness and width at a temperature at which the composition does not begin to cure, in order to obtain a stack separator. of fuel with high thickness accuracy. For example, when an extruder is used, the curable resin resin composition in powder or lump form is loaded into an extruder equipped with a sheet molding die at a temperature of 60-100 ° C, is subjected to extrusion molding, and It is then collected on a conveyor belt or the like. For precision molding of even greater thickness, calendering is preferably carried out with a roller or calender after molding in the extruder. Extrusion molding is preferably carried out under vacuum in order to remove pores or air in the sheet. When a roller is used, the powder-curable conductive resin composition or lump form is introduced between two rollers maintained at a temperature of 20-100 ° C, which rotate at the same speed, for forming on a sheet, and is then collected by a Conveyor belt or similar. For molding with even greater thickness precision, the calendering is preferably performed with a roller or calender after sheet formation.

The cured conductive resin product obtained from the curable conductive resin composition of the invention is not particularly limited in its use, but was developed for the purpose of manufacturing a fuel cell separator, a battery assembly, an electrode or a heat release plate, and therefore is very suitable as a fuel separator, assembly for a battery, electrode or heat release plate.

For manufacturing a fuel cell separator, an assembly for a battery, an electrode or a heat release plate from a sheet obtained in the manner described above, the sheet is cut or stamped to the desired size, after which inserts a sheet or two or more sheets into a grooved mold on one side or on both sides, and is cured hot with a compression molding machine, to obtain a fuel cell separator, an assembly for a battery, an electrode or a heat release plate. The cavity is placed under vacuum preferably during curing in order to obtain a defect-free product. After curing, any deformation in the product is preferably corrected by cooling under compression of 3 MPa or greater between the plates of the press maintained at 10-50 ° C.

As for the conditions for curing, it is important to find and select the optimum temperature for the type of composition. For example, the conditions can be suitably determined in a temperature range of 120-200 ° C, for a period of 30-1200 seconds. When this curing is finished, a completely cured product can be obtained by post-curing in a temperature range of 150-200 ° C for a period of 10-600 minutes. Post-curing can eliminate deformation in the product if a pressure of 5 MPa or greater is applied.

The fuel cell separator, an assembly for a battery, an electrode or a heat release plate of the invention preferably has the following characteristics. Specifically, the volume resistivity is preferably not more than 2 x 10-2 Ωcm and more preferably not more than 8 x 10-3 Ωcm, with 5 x 10-3 Ωcm or less being particularly preferred for use as a battery separator. fuel. The contact resistance is preferably not more than 2 x 10-2 Ωcm2, more preferably not more than 1 x 10-2 Ωcm2 and especially 7 x 10-3 Ωcm2.

The thermal conductivity is preferably at least 1.0 W / m · K, more preferably at least 4.0 W / m · K and especially at least 10 W / m · K. The gas permeability, which is an important characteristic for a fuel cell separator, is preferably not more than 1 x 10-6 cm2 / s, more preferably not more than 1 x 10-8 cm2 / s and especially not greater than 1 x 10-9 cm2 / s.

Fig. 3 shows an embodiment of a cured sheet grooved on both sides. The use of such cured sheets grooved on both sides for the construction of fuel cells is known and an explanation thereof is not considered necessary (see, for example, Japanese Unexamined Patent Publication SHO NO. 5853167).

The curable conductive resin composition of the invention allows the formation of a continuous sheet even with high compaction of the carbon material, and is therefore optimal for use as a composite material in fields that require thickness accuracy, such as battery separators. fuel, an assembly for a battery, an electrode or a heat release plate. Cured products obtained from it exhibit the electrical conductivity and thermal conductivity of graphite without limits, and are highly functional from the point of view of thermal resistance, corrosion resistance and molding precision. Therefore, they are useful in the field of electronics and for uses such as electrical and mechanical devices or vehicles, being particularly suitable as materials for fuel cell separators, an assembly for a battery, an electrode or a release plate of heat

EXAMPLES

The present invention will be explained in greater detail below by way of examples, it being understood that they are not in any way limiting the invention.

The materials used were as follows.

Component (A) (curable resin composition)

A1: Elastomer

NBR1 (acrylonitrile-butadiene rubber; Nipol DN003 manufactured by Nihon Zeon, Mooney viscosity (ML1 + 4 (100 ° C): 78)

NBR2 (acrylonitrile-butadiene rubber; Nipol 1312 manufactured by Nihon Zeon, Mooney viscosity (ML1 + 4 (100 ° C): not determinable due to its liquid form)

EPDM (ethylene-propylene-diene rubber; EP25 manufactured by Nihon Synthetic Rubber, Mooney viscosity (ML1 + 4 (100ºC): 90)

SBR (styrene-butadiene rubber; SL574 manufactured by Nihon Synthetic Rubber, Mooney viscosity (ML1 + 4 (100ºC): 64)

A2: Reactive radical resin

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

VE1 (vinyl ester resin; sample containing 5% by weight of diallyl phthalate based on phenolic novolac, manufactured by Showa Highpolimer Co. Ltd; viscosity: 2.1 (Country, 80 ° C))

VE2 (vinyl ester resin; H-600 manufactured by Showa Highpolimer Co. Ltd.)

UP (unsaturated polyester resin; Upica 5836 manufactured by Nihon Upica)

A3. Organic peroxide

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

Component (B) (carbon material)

B1: A fine graphite powder containing boron was obtained by the following method.

Coke LPC-S manufactured by Nippon Steel Chemical Co., Ltd., a non-acicular (natural calcined) coke (referred to hereafter as "coke A") was sprayed grossly to a size of 2-3 mm with a sprayer (product of Hosokawa Micron Co., Ltd.). The pulverized crude product was finely pulverized with a jet mill (IDS2UR, product of Nihon Pneumatic Co., Ltd.). It was then adjusted to the desired particle size by sieving. Particles of 5 μm and smaller were removed by air classification using a turboclassifier (PC15N, product of Nissin Engineering Co., Ltd.). After adding 0.6 kg of boron carbide (B4C) to a 14.4 kg portion of the finely adjusted powdered product, the mixture was mixed for 5 minutes using a Henschel mixer at 800 rpm. The mixture was then placed in a graphite vessel fitted with a lid with an inside diameter of 40 cm and a volume of 40 liters, and the vessel was placed in a graphite furnace equipped with graphite heater and graphitized at a temperature of 2900 ° C . After allowing to cool, the powder was removed to obtain 14 kg of powder. The resulting fine graphite powder had an average particle size of 20.5 μm, a reticule spacing (Co value) of 6.716 Ǻ and a B content of 1.3% by weight.

B2: Fine boron-free graphite powder was obtained by the following method.

Coke A was sprayed grossly to a size of 2-3 nm with a sprayer. The powdered raw product was finely pulverized with a jet mill. It was then adjusted to the desired particle size by sieving. The particles of 5 μm and smaller were removed by air classification using a turboclassifier. The powder was then placed in a graphite vessel provided with a lid with an inside diameter of 40 cm and a volume of 40 liters, and the vessel was placed in a graphite furnace equipped with graphite heater and graphitized at a temperature of 2900 ° C . After allowing to cool, the powder was removed to obtain a fine graphite powder. The resulting fine graphite powder had an average particle size of 20.5 μm, a reticule spacing (Co value) of 6.758 Ǻ and a B content of 0% by weight.

LUFG: Artificial graphite: UFG30 manufactured by Showa Denko, K.K.)

EXP: Expanded Graphite; EXP-50EL manufactured by Nihon Graphite Industry.

VGCF: Carbon fiber produced in the vapor phase; VCGF-G (fiber diameter: 0.1-0.3 μm, fiber length: 10-50 μm) manufactured by Showa Denko, K.K.

CNT: Carbon nanotubes that were obtained by the following method.

On a graphite bar with a diameter of 6 mm and a length of 50 mm, a hole with a diameter of 3 mm and a depth of 30 mm was opened from the end along the central axis, and compacted inside a mixed powder of rhodium (Rh): platinum (Pt): graphite (C) in a weight ratio of 1: 1: 1, to make an anode. A cathode made of 99.98% pure graphite with a diameter of 13 mm and a length of 30 mm was manufactured separately. The electrodes were placed opposite each other in a reactor and connected to a DC power source. The inside of the reactor was replaced with 99.9% helium gas, and a direct current arc discharge was performed. The soot (chamber soot) that adhered to the inside of the reactor and the soot accumulated in the cathode (cathode soot) were collected. The pressure and current conditions in the reactor were 60 Torr and 70 A. During the reaction, the separation between the anode and the cathode was constantly maintained at 1-2 mm.

The collected soot was introduced into a mixed solvent 1: 1 of water and ethanol and subjected to ultrasonic dispersion, after which the dispersion was recovered and the solvent was removed with a rotary evaporator. The sample was dispersed by ultrasound in a 0.1% aqueous solution of benzalkonium chloride as an anionic surfactant, and then centrifuged at 5000 rpm for 30 minutes, after which the dispersion was recovered. The dispersion was then heat treated for 5 hours in air at 350 ° C for modification in order to obtain carbon nanotubes with a fiber diameter of 1-10 nm and a fiber length of 0.5-5 μm.

The properties of the cured product were measured by the following methods.

Inherent volume resistivity:

Measured by the method of the four probes according to JIS K7194.

Contact resistance: Using the device shown in Fig. 4, a test piece 21 (20 mm x 20 mm x 2 mm) and a carbon panel 22 (1.5 x 10-3 Ωcm, were contacted 20 mm x 20 mm x 1 mm), were stratified between copper plates 23, and a 98 N load was applied. A direct current of 1 A was passed through it in a transverse direction to the feed, and then put into contact the terminals 24 with the interface between the test piece 21 and the carbon panel 22 to measure the voltage, thus calculating the resistance value. This value was multiplied by the area of the contact cross section in order to obtain the contact resistance.

Flexural strength, flexural modulus and flexural tension:

A test piece was measured by the 3-point flexural strength test method under conditions with a clearance of 64 mm and a folding rate of 2 mm / min, according to JIS K6911. The size of the test piece was 100 x 10 x 1.5 mm.

Thermal conductivity:

A test piece (Ø 10 mm, thickness: 1.7 mm) was measured by the laser flash method (T1 / 2 method using a LF / TCM Laser Thermal Flash Constant Measurement Apparatus FA8510B, manufactured by Rigaku Denki ), in conditions of temperature of 80ºC, vacuum, and ruby laser light (excitation voltage: 2.5 kV).

Gas permeability:

It was measured according to method A of JIS K7126, using He gas at 23 ° C.

Sheet conformability:

Using two rollers of 10 inches (25 cm) under conditions of roller temperature of 60 ° C, a roller separation width of 2 mm and a rotation speed of 15 rpm, the curable conductive resin composition for sheet molding was introduced, and conformability and appearance were evaluated.

Boron content of carbon material:

It was measured using a coupled inductive plasma mass spectrometer (ICP-MS) (SPQ9000, product of Seiko Instrument Inc.)

Surface Accuracy:

The surface of the cured sheet is divided evenly into 16 sections, the thickness of the sheet at the center point of each section is measured, and the arithmetic average of the thickness is calculated.

Examples 1-5, 6-15, Reference Example 6, and Comparative Example 3

In Examples 1-15 and Comparative Example 3, a pressurizing mixer (volume: 1 L) was used for 1 minute to knead an elastomer component under conditions of temperature of 70 ° C and a rotation speed of 40 rpm. Next, a reactive radical resin and a carbon material were loaded and kneaded with the above for 5 minutes, after which DCP was loaded and kneaded with all of the above for 2 minutes. The total volume of the composition was adjusted to fill 80% by volume of the kneader volume. After kneading, the composition was molded on a 2 mm thick sheet using a 10 inch (25 cm) double roller under conditions of 60 ° C roller temperature, 2 mm roller separation width and high rotation speed of 15 rpm, the sheet was cut and inserted into a matrix capable of forming a 100 x 100 x 1.5 mm plate, and a 50 m compression molding machine was used for 5 minutes of curing with a temperature of 170 ° C matrix and a pressure of 30 MPa to obtain a cured product.

Comparative Examples 1-2

In Comparative Examples 1-2, a pressurizing kneader (volume: 1 L) was used for 1 minute to knead a charged elastomer component under conditions of temperature of 70 ° C and rotation speed of 40 rpm. Next, a reactive radical resin and a carbon material were loaded and kneaded with the above for 5 minutes, after which DCP was loaded and kneaded with all of the above for 2 minutes. The total volume of the composition was adjusted to fill 80% by volume of the kneader volume. The kneaded product was inserted into a matrix capable of forming a 100 x 100 x 1.5 mm plate, and a 50 m compression molding machine was used for 5 minutes of curing with a matrix temperature of 170 ° C and a pressure 30 MPa to obtain a cured product.

Example 16

In Example 16, the composition used in Example 1 was formed on a 1.7 mm thick uncured sheet using a 10 inch (25 cm) double roller under roller temperature conditions of 60 ° C, a separation width of 1.7 mm rollers and an equal rotation speed of 15 rpm, the uncured blade was cut to a size of 280 x 200 mm and the cut sheets were grafted into a matrix capable of forming a plate with a size of 280 x 200 x 1.5 mm and had 1 mm slots opening on both sides, and a 500 ton compression molding machine was used for 3 minutes of curing with a die temperature of 170 ° C and a pressure of 60 MPa to obtain a cured body grooved on both sides.

Example 17

In Example 17, the composition used in Example 1 was molded by extrusion on a 1.8 mm thick and 70 mm wide sheet using a single screw extruder of 60 Ø under temperature conditions of 6090 ° C and a speed of rotation of 40 rpm, the uncured sheet was cut into sheets that were 200 x 70 mm in size and the cut sheets were arranged in parallel on a matrix capable of forming a plate with a size of 280 x 200 x 1.5 mm and that had 1 mm separation grooves on both sides, and a 500 ton compression molding machine was used for 3 minutes of curing with a matrix temperature of 170 ° C and a pressure of 60 MPa to obtain a cured body grooved on both sides.

Comparative Example 4

In Comparative Example 4, the composition used in Example 1 was pulverized using a refrigerated Wiley mill (product of YOSHIDA SEISAKUSHO CO., LTD), the cut sheets were arranged in parallel in a matrix capable of forming a plate with a size of 280 x 200 x 1.5 mm and having 1 mm slots on both sides, and a 500 ton compression molding machine was used for 3 minutes of curing with a die temperature of 170 ° C and a pressure of 60 MPa to obtain a body cured on both sides.

Comparative Example 5

In Comparative Example 5, the composition used in Comparative Example 2 was pulverized using a refrigerated Wiley mill (product of YOSHIDA SEISAKUSHO CO., LTD), the cut sheets were arranged in parallel in a matrix capable of forming a plate with a size 280 x 200 x 1.5 mm and had 1 mm slots on both sides, and a 500 ton compression molding machine was used for 3 minutes of curing with a matrix temperature of 170 ° C and a pressure of 60 MPa to obtain a cured body grooved on both sides.

Example 18

In Example 18, the properties of the cured sheet grooved on both sides of Example 16 were evaluated as a fuel cell separator.

Example 19

In Example 19, the properties of the grooved cured body on both sides of Example 17 were evaluated as a fuel cell separator

Comparative Example 6

In Comparative Example 6, the properties of the grooved cured body on both sides of Comparative Example 4 were evaluated as a fuel cell separator

Comparative Example 7

In Comparative Example 7, the properties of the grooved cured body on both sides of Comparative Example 5 were evaluated as a fuel cell separator

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

Table 1

Example 1

Example 2 Example 3 Example 4 Example 5 Ex. Ref.6 Ex. Comp. one Ex. Comp. 2 Ex. Comp. 3

Elastomer

NBR1 twenty 10 twenty 80 90

NBR2

twenty

EPDM

fifteen 10

SBR

30

Reactive Radical Resin

ALE 80 85 70 80 80 100

VE1

80 twenty 10

Organic Peroxide

DCP 2 2 2 2 2 2 2 2 2

Carbon material

B1 500 500 500 500 600 500 500 500  600

Sheet conformability * 1

OR OR OR OR OR OR X X OR

Volume resistivity

mΩ · cm 5 4 8 5 4 fifteen 5 3 33

Contact resistance

mΩ · cm2 6 5 7 6 5 18 6 8 35

Thermal conductivity

W / mK fifteen 17 14 fifteen  fifteen 12 17 fifteen  8

Flexural strength

MPa  Four. Five 55 fifty 55  65 fifteen 30 65  8

Flex module

GPa 14 fifteen 12 fifteen  twenty 5 12 twenty-one  0.5

Bending effort

% 0.5 0.5 0.7 0.6 0.5 ≥3.5 0.4 0.3  ≥3.5

�

* 1 O: Continuous conformation with uniform blade success.

Impossible to form a leaf; It was kept in powder form X:

Table 2

Example7

Example8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15

Elastomer

NBR1 twenty twenty twenty twenty twenty 30 30 30 30

Reactive Radical Resin

VE2 80 80 80 80 80

UP

70 70 70 70

Organic peroxide

DCP 2 2 2 2 2 2 2 2 2

Carbon material

B1 500 400 400 350 350

B2

500 400 350 300

UFG

100 100

EXP

100 100

VGCF

fifty

CNT

fifty fifty

Boron content of carbon material (% weight)

1.3 0 1.14 1.12 0 0.89 0 0.97 0

Volume resistivity

mΩ · cm 4 fifteen 3 2 10 6 twenty 5 33

Contact resistance

mΩ · cm2 6 twenty 4 3 16 8 40 6 35

Thermal conductivity

W / mK fifteen 16 12 eleven eleven 18 19 8 8

Flexural strength

MPa fifty 47 48 53 52 Four. Five 44 41 8

Flex module

GPa 10 eleven eleven 12 12 10 eleven 9 one

Bending effort

% 0.5 0.5 0.5 0.5 0.5 0.6 0.6 0.6 0.6

15 16

Table 3

Sheet Press Conformation

Powder Press Conformation

Example 16

Example 17 Ex. Comp. 4 Ex. Comp. 5

Lamination

Extrusion

Surface accuracy

mm ± 0.04 ± 0.04 ± 0.08 ± 0.12

Coefficient of gas permeability

cm 2 / s 10 -10 10 -9 10-5 10-5

Table 4

Example 18

Example 19 Ex. Comp. 6 Ex. Comp. 7

Volume resistivity

mΩ · cm 5 5 8 10

Contact resistance

mΩ · cm2 6 6 9 12

Thermal conductivity

W / mK fifteen fifteen 16 16

Table 1 shows that the addition of an elastomer with a high Mooney viscosity allows satisfactory sheet forming even with a high degree of compaction of the carbon material. When no elastomer was present, the addition of the carbon material in a proportion greater than 80% by weight resulted in a compound with a powdery state after kneading. Comparative Example 3 demonstrates that the

The addition of a large amount of elastomer results in less conductivity.

Table 2 shows that the inclusion of boron in the carbon material provides cured products with high conductivity.

Table 3 shows that sheet press forming provides plates in the form of a fuel cell separator with high surface accuracy (thickness accuracy) and satisfactory gas impermeability.

10 Table 4 shows that a cured body grooved on both sides obtained by sheet pressing exhibits satisfactory efficiencies as a fuel cell separator.

According to the invention, the addition of an elastomer with high Mooney viscosity resulted in the obtaining of curable conductive resin compositions with excellent sheet formability and allowed a high degree of compaction of the carbon materials. The use of carbon materials containing 15 boron as fillers provided compositions that exhibited both high conductivity and high heat release properties which, when formed in sheet using an extruder, roller, calender

or analogous and cured by pressure forming, they produced thin fuel cell separators of large area with excellent gas impermeability and surface accuracy.

Industrial Applicability

The curable conductive resin composition of the invention provides cured products with excellent conductivity and heat release properties that are very suitable as materials that could not be obtained in the prior art, for example, in the field of electronics and for various purposes and parts such as electrical products, mechanical parts, vehicle parts and the like, and which are especially useful as materials for separators in fuel cells such as polymer solid fuel cells.

Claims (17)

one.

A curable conductive resin composition characterized in that it comprises (A) a curable resin composition and (B) a carbon material, with a weight ratio of component (A) to component (B) of 70-5: 3095,

characterized in that the curable resin composition of component (A) comprises (A1) an elastomer with a Mooney viscosity (MN1 + 4 (100 ° C)) of 25 or greater in a proportion of 60-10% by weight, (A2) a resin reactive radical in a proportion of 40-90% by weight, the total components (A1) and (A2) being 100% by weight, and (A3) an organic peroxide in a proportion of 0.2-10 parts by weight for 100 parts by weight of (A1 + A2), wherein the reactive radical resin is one or more selected (s) from unsaturated polyester resins, vinyl ester resins, allyl ester resins, urethane resins, resins of diallyl phthalate and 1,2-polybutadiene resins.

2.

The curable conductive resin composition according to claim 1, characterized in that the elastomer of component (A1) is one or a combination of two or more selected from the group consisting of acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber , ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, ethylene-butadiene rubber, fluorinated rubber, isoprene rubber, silicone rubber, acrylic rubber and butadiene rubber.

3.

The curable conductive resin composition according to claim 2, wherein the elastomer of component (A1) is one or a combination of two or more selected from the group consisting of acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber , ethylene-propylene rubber, ethylene propylene-diene terpolymer rubber, and butadiene rubber.

Four.

The curable conductive resin composition according to claim 1, characterized in that the carbon material of component (B) is a material selected from the group consisting of graphite powder, artificial graphite powder, natural graphite powder, expanded graphite powder , carbon fiber, carbon fiber produced in the vapor phase with a fiber diameter of 0.05-10 μm and a length of 1-500 μm, carbon nanotubes with a diameter of 0.5-100 nm and a length of 0.01-10 μm, and carbon black, or a mixture thereof.

5.

The curable conductive resin composition according to claim 4, wherein the graphite powder is graphite powder with an average particle size of 0.1-150 μm and a reticule spacing (Co value) of 6.745 Ǻ or less .

6.

The curable conductive resin composition according to claim 1, characterized in that when the carbon material of component (B) is pressurized to an apparent density of 1.5 g / cm 3, the electrical resistivity of the powder in the direction perpendicular to the Pressurization direction is not greater than 0.07 Ωcm.

7.

The curable conductive resin composition according to claim 1, characterized in that the carbon material of component (B) contains boron in a proportion of 0.05-10% by weight.

8.

The curable conductive resin composition according to claim 1, which is used for sheet molding.

9.

A process for producing an uncured sheet, characterized in that the curable conductive resin composition according to any one of claims 1 to 8 is shaped while in an uncured state, using a type of forming machine such as an extruder , roller and calender.

10.

An uncured sheet produced by the process according to claim 9.

eleven.

The uncured sheet according to claim 10, which is 0.5-3 mm thick and 20-3000 mm wide.

12.

A process for producing a slotted cured sheet, characterized in that the uncured sheet according to claim 10 is cut or stamped, and the sheet is supplied to a die and cured by heating with a compression molding machine.

13.

A fuel cell separator, an assembly for a battery, an electrode or a heat release plate, produced by the process described in claim 12 using a die grooved on one side or on both sides .

14.

A fuel cell separator obtained by curing the uncured sheet according to claim 10.

fifteen.

A fuel cell separator comprising a cured body obtained by supplying the curable conductive resin composition according to any one of claims 1 to 8 or the uncured sheet according to claim 10 to a die grooved by the two faces and curing it with a

compression molding machine, the fuel cell separator being characterized as having a volume resistivity of not more than 2 x 10-2 Ωcm, a contact resistance not exceeding 2 x 10-2 Ωcm2, a thermal conductivity of at least 1 , 0 W / m · K and a gas permeability of not more than 1 x 10-6 cm2 / s, and containing at least 0.1 ppm of boron. A fuel cell separator, an assembly for a battery, an electrode or a heat release plate characterized by a grooved conductive cured resin sheet comprising the curable conductive resin composition in accordance with the claim 1. 17. The fuel cell separator, an assembly for a battery, an electrode or a heat release plate according to claim 16, characterized in that the component elastomer (A1) is one or one 10 combination of two or more selected from the group consisting of acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, ethylene-butadiene rubber, fluorinated rubber, isoprene rubber , silicone rubber, acrylic rubber and butadiene rubber. 18. The fuel cell separator according to claim 16, characterized by having a 15 volume resistivity not exceeding 2 x 10-2 Ωcm, a contact resistance not exceeding 2 x 10-2 Ωcm2, a thermal conductivity of at least 1.0 W / m · K and a gas permeability not greater than 1 x 10-6 cm2 / s, and for containing at least 0.1 ppm of boron. PRESS