JP2008140668A - Separator material for polymer electrolyte fuel cell and manufacturing method thereof - Google Patents

Abstract

The present invention provides a fuel cell separator material having excellent material strength, particularly high strength at a high temperature of about 80 ° C. to 100 ° C., and excellent material properties such as electric resistance, gas impermeability, and fracture strain, and a method for producing the same. To do.
Carbon is produced by a binder containing a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, a phenol resin curing agent, a silane compound having a polysiloxane structure, and a curing accelerator as essential components. A separator for a polymer electrolyte fuel cell, comprising a carbon / resin cured molded body with powders bound thereto. The first manufacturing method for manufacturing this separator material is to knead a resin solution in which these binder components are dissolved in an organic solvent and carbon powder, and to fill the molding powder obtained by pulverizing the kneaded material into a preforming mold and pressurize it. The obtained preform is inserted into a mold and hot-press molded. Also, in the second production method, a slurry in which carbon powder is dispersed in the resin solution is applied on a film and released from the mold to produce a green sheet, and the green sheet is laminated in a mold and hot-press molded.
[Selection figure] None

Description

  The present invention relates to a separator material for a polymer electrolyte fuel cell used in, for example, automobiles and small distributed power sources, and a manufacturing method thereof.

  Solid polymer fuel cells directly convert the chemical energy of fuel into electrical energy, have high conversion efficiency into electrical energy, and are expected to be developed in the future as compact and distributed power sources including automobile power supplies. Yes.

  A fuel cell has an electrolyte membrane, a catalyst electrode carrying a catalyst such as platinum on both sides thereof, and a gas flow path for supplying a fuel gas such as hydrogen or an oxidant gas such as oxygen or air to each electrode. It is composed of a stack in which single cells made of provided separators, etc., and a current collector provided on the outside thereof.

  This separator requires a high degree of gas impermeability to supply the fuel gas and oxidant gas to the electrode in a completely separated state, and the internal resistance of the battery is reduced to increase power generation efficiency. Thus, high conductivity is required. In addition, high strength of the material is required because the single cells are tightly tightened when the stack is assembled.Furthermore, when mounted on an automobile, cracks may occur due to expansion and contraction due to vibration, impact, temperature change, etc. Material properties that do not break are required.

  A carbonaceous material has been conventionally used as a separator material that requires such material characteristics, and carbon powder such as graphite is bound with a thermosetting resin as a binder, and an integrated carbon / A resin-cured molded body is preferably used.

  However, in order to impart high conductivity to the separator material, it is necessary to increase the mixing ratio of the carbon powder serving as the conductive filler, and as a result, the toughness of the carbon / resin cured molded body is lowered, and further, thermosetting Since the resin is hard, there is a drawback that, when assembling the battery stack, the separator is easily cracked when the single cells are stacked and tightened.

  Therefore, Patent Document 1 proposes a fuel cell separator material comprising a rubber composition in which 100 to 150 parts by weight of graphite powder and 100 to 150 parts by weight of carbon black are blended with respect to 100 parts by weight of the rubber component. ing. Patent Document 1 intends to prevent breakage and deformation at the time of assembling a single cell by the elasticity unique to the rubber composition.

  In addition, proposals have been made to improve or improve these characteristics by treating the surface of carbon powder. For example, Patent Document 2 discloses an aqueous dispersion of a carbonaceous material and a water-repellent substance as an organic solvent. Carbonaceous materials for fuel cells such as gas diffusion electrode layers, which are obtained by dripping a dissolved solution and performing a water repellent treatment, have been proposed. This relates to a carbonaceous material having both conductivity and water repellency. However, when water repellency is imparted to the carbon material, the strength characteristics are lowered.

Patent Document 3 discloses a composite material in which a carbonaceous powder is dispersed in a matrix, and the matrix has a resin coating layer that covers the carbonaceous powder and a resin that is higher than the resin that forms the resin coating layer. A composite material for forming a fuel cell separator characterized by being formed of a heat-resistant resin-reinforced phase, Patent Document 4 contains composite particles obtained by coating a conductive carbon material with rubber and a thermosetting resin. A fuel cell separator formed by molding a conductive molding material is disclosed.
JP 2001-216777 A JP 2003-208905 A JP 2003-257446 A JP 2003-277629 A

  However, it is still insufficient for improving the performance of the separator, and the present inventors have conducted intensive research on the improvement of the material of the carbon / resin cured molded body, and by using an epoxy resin and a silane compound in combination, It has been found that material properties suitable as a separator material are imparted.

  In particular, by using a silane compound having a polysiloxane structure, the bending strength of the carbon / resin-cured molded article is small and the fracture strain is large, that is, it has excellent mechanical strength characteristics at room temperature and high temperature. It was confirmed that the battery had suitable characteristics as a battery separator material.

  The present invention has been completed on the basis of this finding, and its purpose is excellent in material strength, particularly low strength drop at high temperature, high strength at a temperature of about 80 to 100 ° C. during battery operation, and other materials. An object of the present invention is to provide a polymer electrolyte fuel cell separator material having excellent properties and a method for producing the same.

  In order to achieve the above object, a separator for a polymer electrolyte fuel cell according to the present invention comprises a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, a phenol resin curing agent, and a polysiloxane. It is characterized by comprising a carbon / resin cured molded body in which carbon powder is bound by a binder containing a silane compound having a structure and a curing accelerator as essential components.

  The first production method according to the present invention for producing this solid polymer fuel cell separator material is a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, a phenol resin curing agent, A resin solution in which a silane compound having a siloxane structure and a curing accelerator are dissolved in an organic solvent and carbon powder are kneaded, then the organic solvent is removed, and then the kneaded product is pulverized to obtain a molding powder. It is characterized in that a preform is prepared by placing the upper mold and pressurizing to 1 to 10 MPa, and then charging the preform into a mold and hot pressing.

  Further, the second production method according to the present invention for producing this solid polymer fuel cell separator material is a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, a phenol resin curing agent. Then, a carbon powder is dispersed in a resin solution in which a silane compound having a polysiloxane structure and a curing accelerator are dissolved in an organic solvent to prepare a slurry. Then, the slurry is applied onto the film and dried, and then separated from the film. A green sheet is produced by molding, the green sheet is punched into a predetermined shape, laminated in a mold, and hot-press molded.

  According to the present invention, the decrease in strength at a high temperature that is the operating temperature of the polymer electrolyte fuel cell is small, the material strength is excellent, and the conductivity and gas impermeability are at a favorable level, which is suitable as a separator material. A separator for a polymer electrolyte fuel cell and a method for producing the same are provided.

  The separator for a polymer electrolyte fuel cell of the present invention is formed from a carbon / resin cured molded body in which carbon powder is bound by a binder, and the component composition constituting the binder is specified. It is characterized by.

  Among the components constituting the binder, the mixed resin is a mixture of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, and the bifunctional aliphatic alcohol ether type epoxy resin is generalized. 1 is represented by 1, O is oxygen, R is an alkylene group having 2 to 10 carbon atoms, n is an integer of 1 or more, and G is a compound composed of a glycidyl group. The number of carbon atoms contained between glycidyl groups is preferably an epoxy resin having 6 or more.

(Chemical formula 1)
G-O- (R-O) n-G

  As can be seen from the chemical formula 1, since the bifunctional aliphatic alcohol ether type epoxy resin has a linear structure, it has a structure in which molecules easily move, exhibit flexibility, and rubber elasticity easily occurs. Accordingly, flexibility, elongation, breaking strain and the like are increased.

  Typical examples of the bifunctional aliphatic alcohol ether type epoxy resin represented by Chemical Formula 1 include hexanediol type epoxy resin, polyethylene glycol type epoxy resin, polypropylene glycol type epoxy resin, polyoxytetramethylene glycol type epoxy resin, and the like. Among these resins, those having a relatively small proportion of oxygen atoms are preferable. When the number of oxygen is reduced, water resistance is improved and water absorption swelling is reduced.

  When the number of carbon atoms between the glycidyl groups represented by the general formula of Chemical Formula 1 increases, the flexibility of the resin increases, so that the breaking strain increases, but the strength decreases. And, in the case of an alcohol ether type epoxy resin having less than 6 carbon atoms, for example, 4 carbon atoms, the distance between glycidyl groups is too short, so that the flexibility is lowered. Therefore, in order to ensure flexibility, an epoxy resin having 6 or more carbon atoms contained between glycidyl groups is preferable. However, when the number of carbon atoms between glycidyl groups is 8 or more, the strength is significantly reduced, and the bending strength is also below 30 MPa.

  On the other hand, as the polyfunctional phenol type epoxy resin, for example, the bifunctional phenol type epoxy resin has two epoxy groups in the molecule, and as shown in the general formula 2, for example, like bisphenol A type epoxy resin, The epoxy resin having a benzene ring has a slightly lower elastic modulus of the cured product, but the planar benzene ring makes the molecule difficult to move, the flexibility becomes low, and the elongation becomes small.

  Moreover, as a polyfunctional phenol type epoxy resin, the trifunctional phenol type epoxy resin has three epoxy groups in the molecule and has a benzene ring in the skeleton, as shown in the general formula 3. When cured, it becomes a three-dimensional structure, resulting in a hard and brittle cured product. And the carbon / resin hardening molded object which bound carbon powder as a binder shows high intensity | strength, but since a softness | flexibility and elongation fall, a fracture | rupture distortion becomes very small.

  As the polyfunctional phenol type epoxy resin, it can be used as long as it is a compound having a phenol structure in its molecule and having two or more epoxy groups. For example, bisphenol type epoxy resin, novolac type epoxy resin Orthocresol novolac type epoxy resins, biphenyl type epoxy resins, naphthalene skeleton-containing type epoxy resins, and the like are applied.

  Here, the mixed resin is used as the resin for binding the carbon powder in the present invention because it has excellent flexibility (softness), but has a low strength, a bifunctional aliphatic alcohol ether type epoxy resin, and a high strength. This is because, in combination with a polyfunctional phenol type epoxy resin having low flexibility (flexibility), flexibility (flexibility) and strength are made compatible.

  That is, as a resin for binding carbon powder, a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin is used, and by adjusting the mixing ratio, a balance between flexibility and strength is achieved. In order to achieve both flexibility and strength, the proportion of the bifunctional aliphatic alcohol ether type epoxy resin in the mixed resin is preferably 40% by weight or more. The upper limit is desirably 80% by weight or less.

  Next, the phenol resin curing agent is a curing agent for a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, and is not particularly limited. Cresol novolac resin, xylene type phenol resin, dicyclopentadiene type phenol resin, novolak resin such as bisphenol type novolak resin, bisphenols such as bisphenol A, bisphenol F, bisphenol S, tetrabromobisphenol A, and the bisphenols as the bisphenols A bisphenol-based resin obtained by increasing the molecular weight with diglycidyl ether or by reacting epichlorohydrin with the bisphenol in an excess ratio is used.

  Moreover, what has a polysiloxane structure is applied to the silane compound which is one of the essential components of the binder, and the general formula thereof is represented by Formula 4. However, in Chemical Formula 4, R1 represents a C1-C4 lower alkyl group, R2 represents a C1-C4 lower alkyl group or phenyl group, R3 represents an organic reactive group, m is 1 to 3, n is 0 to 2, and m + n = 3.

  Specifically, R1 is a lower alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group, and R2 is a lower alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group, or phenyl. It is a group.

  R3 is, for example, 3-glycidoxy (epoxy) propyl group, vinyl group, 3-methacryloxypropyl group, N- (2-aminoethyl) 3-aminopropyl group, 3-ureidopropyl group, 3-anilinopropyl group. , 3-mercaptopropyl group, hydroxypropyl group, 2- (3,4-epoxycyclohexyl) ethyl group, and the like, which are bonded to the organic reactive group of the epoxy resin.

  Preferred examples thereof include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyldiethoxymethylsilane, 3-glycidoxypropyldimethoxymethylsilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3- Methacryloxypropyltrimethoxysilane, 3-methacryloxypropyldimethoxymethylsilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropyldimethoxymethylsilane, 3-ureidopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyldi Butoxy methyl silane, hydroxypropyl trimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like.

  These silane compounds are unstable with respect to moisture and easily and quickly hydrolyze to silanol in the presence of moisture. In the hydrolysis reaction, the silane compound and purified water are mixed, for example, at a ratio of 0.1 to 5 equivalents of purified water with respect to 1 equivalent of the alkoxy group of the silane compound, and stirred at a temperature of 15 to 100 ° C. for an appropriate time. Done.

  Taking the trialkoxysilane as an example of the silane compound, the reaction formulas in the case of hydrolyzing to produce silanol and further silanol condensing to form siloxane are shown in Chemical Formula 5 and Chemical Formula 6.

  In addition, when performing a hydrolysis reaction, in order to improve the compatibility of a silane compound and purified water, water-soluble solvents, such as methanol, ethanol, 2-propanol, 1-propanol, and acetone, can also be used.

  Furthermore, acidic catalysts such as formic acid, acetic acid, hydrochloric acid, aluminum chloride, iron chloride, or triphenylphosphine, 1,8-diazabicyclo (5,4,0) undecene-7 (DBU) are used to accelerate the hydrolysis reaction. It is preferable to add a basic catalyst such as

  After performing the hydrolysis reaction, the silane compound is obtained by removing the purified water, the added water-soluble solvent, or the catalyst with an evaporator or the like. These silane compounds are preferably adjusted to a ratio of 2 to 20% by weight in the binder. This is because if the ratio of the silane compound is less than 2% by weight, the heat resistance of the carbon / resin cured molded product is low, and if it exceeds 20% by weight, the strength decreases.

  Examples of the curing accelerator include phosphorus compounds, tertiary amines, imidazoles, organic acid metal salts, Lewis acids, amine complex salts and the like, and these can be used alone or in combination of two or more. It is added in the range of 0.05 to 3 parts by weight with respect to parts.

  As described above, the separator material for a polymer electrolyte fuel cell of the present invention includes a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, a phenol resin curing agent, and a silane having a polysiloxane structure. It is formed from a carbon / resin cured molded body in which carbon powder is bound by a binder containing a compound and a curing accelerator as essential components.

  As the carbon powder, graphite powder such as artificial graphite, natural graphite, expanded graphite, or a mixture thereof is preferably used, and it is preferable to use graphite powder pulverized with an appropriate pulverizer and sieved to adjust the particle size. The particle size of the graphite powder is, for example, an average particle size of 50 μm or less and a maximum particle size of 100 μm or less in order to prevent dropping of graphite powder particles and generation of cracks between particles when providing gas grooves in the separator. It is preferable to adjust.

  In addition, as for the quantity ratio in a carbon / resin hardening molded object, it is preferable that the weight ratio of the resin solid content in a binder and carbon powder shall be 10: 90-35: 65. If the resin solid content is less than 10% by weight and the weight ratio of the carbon powder exceeds 90% by weight, the resin content is small and the fluidity at the time of molding is lowered, so it is difficult to mix uniformly and the composition tends to be non-uniform. . On the other hand, if the resin solid content exceeds 35% by weight and the carbon powder is less than 65% by weight, the moldability is improved, but the electric resistance of the carbon / resin cured molded body increases, leading to a decrease in battery performance. Become.

  In the first production method according to the present invention for producing the separator for a polymer electrolyte fuel cell, first, a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, which are the binder components described above, are used. A resin solution is prepared by dissolving a mixed resin, a phenol resin curing agent, a silane compound having a polysiloxane structure, and a curing accelerator in an appropriate organic solvent such as alcohol, ether, or ketone at a desired weight ratio.

The resin solution and the carbon powder are mixed at an appropriate weight ratio, for example, the resin solid content in the resin solution and the carbon powder at a weight ratio of 10:90 to 35:65, and the kneader, the pressure type kneader, and the twin screw kneading are mixed. Using a suitable kneader such as a machine, the mixture is sufficiently kneaded to produce a uniform kneaded product. The kneaded product is vacuum-dried or air-dried to volatilize and remove the organic solvent, and then pulverized to produce a molding powder.
The molding powder is preferably pulverized to about 0.1 to 1 mm in order to uniformly fill the preforming mold. The molding powder is uniformly filled in the cavity of the preforming mold, and the temperature is higher than the melting point of the resin, for example, Resin melting point + An upper mold heated to about 10 ° C is placed and preformed at a pressure of 1 to 10 MPa to produce a plate-like preform.

  In addition, since the resin film formed on the surface of the carbon powder by crushing the kneaded material is destroyed and the carbon surface is exposed, the decrease in conductivity due to the resin film can be prevented. Furthermore, anisotropy of material properties can be corrected by pulverizing the kneaded material.

  The plate-shaped preform is inserted into a mold having a concavo-convex portion forming a groove serving as a gas flow path of the separator by applying a release agent, and an appropriate pressure and temperature depending on the type of resin used, for example, By performing hot-pressure molding at a pressure of 20 to 50 MPa and a temperature of 150 to 250 ° C., a separator made of a carbon / resin-cured molded body in which the resin is cured and the carbon powder is bound and integrated with the cured resin is manufactured. . The separator material thus manufactured is further machined as necessary.

  In the second production method according to the present invention for producing the separator material for a polymer electrolyte fuel cell, first, a resin solution is produced by the same method as the first production method. The slurry is prepared by setting the concentration to an appropriate level for dispersing the powder into a slurry, and adjusting the quantitative ratio between the resin solution and the carbon powder. In this case, it is preferable to prepare such that the slurry has a viscosity of 100 to 2000 mPa · s, and it is also preferable to use a dispersant in forming the slurry.

  This slurry is applied onto a film of polyester or the like by, for example, a doctor blade. At this time, it is preferable to appropriately adjust the gap between the doctor blade and the film and to apply a release agent to the film. Next, after drying, it is released from the film to produce a green sheet.

  The green sheet is punched into a desired size, and a release agent is applied and laminated in a mold in which concave and convex portions that form a groove serving as a gas flow path of the separator are carved and mounted. Note that the number of stacked green sheets is changed according to the thickness depending on the location of the separator.

  Next, the resin was cured by carbonization at a suitable pressure and temperature, for example, a pressure of 20 to 50 MPa and a temperature of 150 to 250 ° C., depending on the type of resin used, and the carbon powder was bound with the cured resin and integrated. The separator material which consists of a carbon / resin hardening molded object is manufactured. The separator material thus manufactured is further machined as necessary.

  Examples of the present invention will be specifically described below in comparison with comparative examples.

Synthesis of silane compounds;
(1) Synthesis of silane compound 1.
A three-necked flask (capacity 500 ml) equipped with a thermometer and a reflux condenser was charged with 100 parts by weight of 3-glycidoxypropyltrimethoxysilane, 25 parts by weight of purified water, 1 part by weight of acetic acid and 100 parts by weight of methanol. The reaction was stirred at 100 ° C. for 5 hours for hydrolysis. Thereafter, the mixture was transferred to an eggplant-shaped flask and concentrated on a rotary evaporator at a temperature of 50 ° C. for 1 hour to remove the produced water, methanol, and the like, thereby synthesizing a silane compound 1 having a polysiloxane structure.
(2) Synthesis of silane compound 2;
Silane compound 2 having a polysiloxane structure was synthesized by the same method as silane compound 1 except that 3-aminopropyltrimethoxysilane was used instead of 3-glycidoxypropyltrimethoxysilane.

Examples 1-4, Comparative Examples 1-2
A polyoxytetramethylene glycol type epoxy resin (epoxy resin A) is used as a bifunctional aliphatic alcohol ether type epoxy resin, a novolac type epoxy resin (epoxy resin B) is used as a polyfunctional phenol type epoxy resin, and a novolak as a phenol resin curing agent. Type phenol resin, 2-ethyl 4-methylimidazole as a curing accelerator, and silane compound 1 or silane compound 2 as a silane compound were used.

  In Comparative Example 1, a silane compound was not used as a binder component, and in Comparative Example 2, 3-glycidoxypropyltrimethoxysilane was used as it was without hydrolysis as a silane compound.

  These components are mixed at a ratio (% by weight) shown in Table 1 to form a binder, and 25 parts by weight of this binder is combined with 1 part by weight of a dispersant (anionic surfactant) and methyl ethyl ketone (organic solvent) 110. A resin solution was prepared by dissolving in parts by weight.

  To this resin solution was added 100 parts by weight of natural graphite powder whose particle size was adjusted to a ratio of 50% by average particle size of 50 μm, 10% by weight of 10 μm, and 40% by weight of 3 μm. The entrained air was deaerated to prepare a slurry having a viscosity of 200 mPa · s.

  This slurry was put into a hopper of a doctor blade molding machine, and after adjusting the gap between the doctor blade and the film, it was applied onto a polyester film coated with a release agent. Next, it was blown and dried to volatilize and remove methyl ethyl ketone, and then released to produce a green sheet having a thickness of about 0.3 mm.

  This green sheet is punched into a size of 200 × 200 mm, and in a molding die having an outer shape of 270 × 270 mm in which a groove-shaped portion having a width of 1 mm and a depth of 0.6 mm is engraved within a range of 200 × 200 mm, Accordingly, a predetermined number of green sheets were laminated and hot-press molded at a pressure of 40 MPa and a temperature of 180 ° C. In this way, a separator material having a size of 200 × 200 mm, a thickness of 0.8 mm, and a thinnest part thickness of 0.2 mm was manufactured.

  A test piece was produced from the separator material thus produced, and the material properties were measured by the following method. The results are shown in Table 2.

(1) Bending strength (MPa);
The bending strength at room temperature and 80 degrees was measured according to JIS R1601.

(2) Breaking strain (%);
The breaking strain at room temperature and 80 ° C. was measured according to JIS R1601.

(3) Specific resistance (mΩ · cm);
It was measured according to JIS C2525.

(4) Contact resistance (mΩ · cm ² );
While the test pieces were brought into contact with each other at a pressure of 1 MPa, measurement was performed at an energization amount of 1A.

(5) Gas permeability coefficient (mol · mm ⁻² · sec ⁻¹ · MPa ⁻¹ );
The amount of gas permeation per unit cross-sectional area when a differential pressure of 0.2 MPa was applied with nitrogen gas was measured.

(6) Thickness accuracy (μm);
The thickness of 27 points in the separator was measured with a micrometer, and the difference between the maximum value and the minimum value was taken as the thickness accuracy.

  Although the flexibility of Comparative Example 1 is found from Table 2, since the bending strength at 80 ° C. is insufficient, the strength of the separator at a high temperature, which is the operating temperature of the fuel cell, is insufficient. The addition of the silane coupling agent that has not undergone polycondensation in Comparative Example 2 is not effective, and the strength of the separator at high temperatures is insufficient. On the other hand, Examples 1 to 4 have electrical characteristics and gas impermeability suitable for a fuel cell separator material, have a good fracture strain indicating flexibility, and have a bending strength at a high temperature (80 ° C.). I understand that it is expensive.

Claims (5)

Carbon powder is produced by a binder containing a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, a phenol resin curing agent, a silane compound having a polysiloxane structure, and a curing accelerator as essential components. A separator for a polymer electrolyte fuel cell, comprising a bonded carbon / resin cured molded body. The separator material for a polymer electrolyte fuel cell according to claim 1, wherein the proportion of the bifunctional aliphatic alcohol ether type epoxy resin in the mixed resin is 40% by weight or more. The separator material for a polymer electrolyte fuel cell according to claim 1, wherein the proportion of the silane compound in the binder is 2 to 20% by weight. Resin solution and carbon powder in which a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, a phenol resin curing agent, a silane compound having a polysiloxane structure, and a curing accelerator are dissolved in an organic solvent After kneading, the organic solvent is removed, and then the molding powder obtained by pulverizing the kneaded product is filled into a preforming mold, and the upper mold is placed and pressurized to 1 to 10 MPa to produce a preform, A method for producing a separator material for a polymer electrolyte fuel cell, wherein the preform is inserted into a mold and hot-press molded. Carbon powder in a resin solution in which a mixed resin of a bifunctional aliphatic alcohol ether type epoxy resin and a polyfunctional phenol type epoxy resin, a phenol resin curing agent, a silane compound having a polysiloxane structure, and a curing accelerator are dissolved in an organic solvent After the slurry is applied onto the film and dried, the slurry is released from the film to produce a green sheet, and the green sheet is punched into a predetermined shape and laminated in a mold. A method for producing a separator material for a polymer electrolyte fuel cell, characterized by hot-press molding.