JP2003173796A - Separator for fuel cell, its manufacturing method and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator for a fuel cell of excellent gas impermeability, conductivity, and durability, a manufacturing method of the fuel cell separator of excellent moldability and mass production property with less problems in gas impermeability, conductivity, and durability, and a fuel cell using the separator excellent in gas impermeability, conductivity, and durability. <P>SOLUTION: The separator for a fuel cell made by using a conductive material (A) has the conductive material (A) dispersed in a hardened matter under additional cross-linking reaction of novolak phenol resin or phenol dicyclopentadiene resin (B) and a compound (C) with at least two ethylene group unsaturated double bonds. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel cell separator, a method for manufacturing the same, and a fuel cell. More specifically, it is a separator for fuel cells, which has excellent conductivity, gas impermeability, mechanical strength, warpage, cracking, swelling, and other dimensional accuracy, and an internal state of a molded article that is good. The present invention relates to a high-performance fuel cell, which is a simple and stable method for producing a fuel cell separator.

[0002]

2. Description of the Related Art "Fuel cell" refers to a device for extracting electric and thermal energy by utilizing an electrochemical reaction between a fuel and an oxidant, the structure of which is generally through an electrolyte on both sides thereof. The basic structure is a single cell in which the two electrodes provided in 1 are sandwiched by two "separators" provided with a supply path for supplying a fuel such as hydrogen gas or an oxidant such as oxygen gas or air. When high output is required,
A “stack structure” is formed by stacking a plurality of single cells in series, and current is collected by current collector plates provided at both ends of the stack.

There are various types of fuel cells depending on the type of electrolyte, fuel, oxidizer, etc. Among them, solid polymer fuel cells using a solid polymer electrolyte membrane as the electrolyte, hydrogen gas as the fuel, and air as the oxidizer. Alternatively, a methanol direct type fuel cell in which hydrogen is directly extracted from methanol as a fuel inside the fuel cell can efficiently generate power at a relatively low operating temperature of 200 ° C. or less.

The separator used in these fuel cells has gas impermeability so as to stably supply the fuel and the oxidant gas to the electrode in a separated state, and further has conductivity to enhance power generation efficiency. Performance such as durability in the fuel cell operating environment is required.

As a fuel cell separator which requires such performance, for example, a binder is added to carbonaceous powder,
There is a method in which a graphite material obtained by heating, kneading, molding, and firing graphitizing is cut into a separator shape. However, this method has a problem of gas impermeability of the separator because it becomes porous because volatile matter is generated in the firing graphitization step. As a method of solving such a problem of the fired graphite material, a method of impregnating pores of the graphite material with a thermosetting resin and curing the resin to obtain a separator substrate (Japanese Patent Laid-Open No. 22224/1996).
No. 1) is proposed, but this method requires a graphitization step, a molding step, a step of impregnating and hardening a resin, a step of machining into a separator shape, etc., and the steps are complicated. There is a problem with mass productivity and economy.

Further, a method of molding and curing a kneaded material of graphite powder having a specific particle size and a thermosetting resin to prepare a separator (Japanese Patent Publication No. 340/340/1998, JP-A-10-33492).
7) has been proposed, but when a thermosetting resin such as a general-purpose phenol resin specifically described in the publication is used, due to condensed water or gas generated during the reaction,
Bubbles and voids are generated inside and on the surface of the molded product, resulting in an inhomogeneous molded product, and defects such as warpage and swelling occur, which is problematic for use as a fuel cell separator.

[0007]

In view of these problems, an object of the present invention is to provide a fuel cell separator having good gas impermeability, conductivity and durability. Also,
The present invention provides a method for producing a fuel cell separator that has no problems in gas impermeability, conductivity, and durability, and that has good moldability and mass productivity. Furthermore, gas impermeability, conductivity, durability The present invention provides a high-performance fuel cell using a separator excellent in heat resistance.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that addition of a novolac-type phenol resin or the like and a compound having at least two ethylenically unsaturated double bonds By using a fuel cell separator composed of a cross-linked reaction cured product, gas impermeability, conductivity, a fuel cell separator having good durability can be obtained, as well as moldability, of a fuel cell separator having good mass productivity. The present invention finds that it is possible to provide a manufacturing method, and further, it is possible to provide a high-performance fuel cell using a gas cell impermeability, conductivity, and a fuel cell separator having excellent durability. Has been completed.

That is, according to the present invention, in a fuel cell separator using a conductive material (A), the conductive material (A) is a novolac type phenol resin or a phenol dicyclopentadiene resin (B) and an ethylenic unsaturated. It is intended to provide a fuel cell separator characterized by being dispersed in a cured product of an addition crosslinking reaction with a compound (C) having at least two double bonds. Further, the present invention is
The electrically conductive material (A) is kneaded with a novolac type phenol resin or phenol dicyclopentadiene resin (B) and a compound (C) having at least two ethylenically unsaturated double bonds, and then the obtained kneaded product is heat-molded. A method for manufacturing a fuel cell separator is provided. Furthermore, the present invention has a solid polymer electrolyte membrane, an electrode, and the above-mentioned fuel cell separator, the electrodes are closely attached to both sides of the solid polymer electrolyte membrane, and the electrodes are closely attached to each other. A fuel cell having a laminated structure in which the solid polymer electrolyte membrane is sandwiched between the fuel cell separators.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

In the fuel cell separator of the present invention, the conductive material (A) is a novolac type phenol resin or phenol dicyclopentadiene resin (B) and a compound (C) having at least two ethylenically unsaturated double bonds. And an addition-crosslinking reaction with the compound.

The conductive material (A) used in the present invention is not particularly limited, but for example, carbon material, metal,
Examples thereof include metal compounds and conductive polymers, and among these, carbon materials are preferable from the viewpoint of durability.

Examples of the above carbon materials include artificial graphite, natural graphite, glassy carbon, carbon black,
Examples thereof include acetylene black, Ketjen black, and expanded graphite obtained by chemically treating graphite. Of these carbon materials, artificial graphite, natural graphite, and expanded graphite are preferable because they can achieve high conductivity with a small amount. Further, the shape of these carbon materials may be any of fibrous, particulate, foil-like, scale-like, needle-like, spherical, and amorphous.

Among the above shapes, examples of the fibrous carbon material include pitch type and PAN depending on the kind of raw material fiber.
Examples thereof include rayon-based carbon fibers and rayon-based carbon fibers. Among these, carbon fibers manufactured through a carbonization and graphitization process at a high temperature of 2000 ° C. or higher are preferable in consideration of conductivity. The length and shape of the carbon fiber are not particularly limited, but in consideration of the kneading property with the resin, the fiber length is preferably 25 mm or less. Examples of carbon fibers of this length include filaments, chopped strands and milled fibers.

Examples of the above metals and metal compounds include aluminum, zinc, iron, copper, nickel,
Examples thereof include silver, gold, stainless steel, palladium, titanium and boride thereof, zirconium boride, and hafnium boride. The shape of the metal and the metal compound may be any of particle shape, fiber shape, foil shape, amorphous shape and the like.

The above conductive materials may be used alone or in combination of two or more. Further, as long as the effect of the present invention is not impaired, a non-conductive material can be used in combination with the above-mentioned conductive material, or a material obtained by combining a conductive material and a non-conductive material can be used. Examples of such a composite material of a conductive material and a non-conductive material include metal-coated glass fibers, metal-coated glass beads, and metal-coated inorganic fillers.

The conductive material (A) is a compound having at least two ethylenically unsaturated double bonds (B) and the novolac type phenol resin or the phenol dicyclopentadiene resin (B) described below. It is preferably 50 to 95% by weight, particularly preferably 70 to 90% by weight, based on the mixture containing C). When the conductive material (A) is in such a range, the fluidity of the mixture is good, the moldability is excellent, and the excellent conductivity required for the fuel cell can be obtained.

The phenol resin used in the present invention is a novolac type phenol resin or a phenol dicyclopentadiene resin (B). Examples of the novolac-type phenol resin include a novolac-type phenol resin obtained by a reaction of a phenol-based compound and a formaldehyde supplying substance; and a phenol resin obtained by a reaction of a xylene resin and a phenol-based compound. The phenol dicyclopentadiene resin used in the present invention is a resin represented by the general formula (1).

[Chemical 1] (In the formula, A is a residue of a phenolic compound, and n is 0.
Alternatively, it is an integer of 1 to 10. In addition, a modified product of the above-mentioned phenol resin can also be used. These may be used alone or in combination of two or more.

Among the novolac type phenol resins produced by the reaction of the above-mentioned phenolic compound and the formaldehyde supplying substance, the bond of the methylene group to the aromatic ring contained in one molecule of the phenol resin is bonded to the para position with respect to the phenolic hydroxyl group. A novolac type phenolic resin having a ratio of the number bonded to the ortho position (hereinafter referred to as O / P ratio) to 3 or more, or a novolac type phenolic resin having an ethylenically unsaturated double bond in the molecule. It is particularly preferable that

The O / P ratio of novolac type phenolic resin is defined as follows. The novolac type phenol resin has a case where the bonding method of the methylene group in one molecule is bonded at the ortho positions with respect to the hydroxyl groups of each aromatic ring, and at the ortho position and the para position.
There are three cases where the para positions are linked to each other. Therefore, the O / P ratio is 1 of the number of methylene groups bonded at the para-position and the para-position to the hydroxyl group of the aromatic ring and the number of methylene groups bonded at the ortho-position and the para-position. / 2
Is expressed by the ratio of the sum of the number of methylene groups bonded at the ortho positions and the half of the number of methylene groups bonded at the ortho positions and the para position to the sum of ] Can be calculated.

[0021]

[Equation 1]

In the formula [1], a, b and c are as follows. a: the number of methylene groups bonded at the ortho positions b: number of methylene groups bonded at the ortho positions and para position c: number of methylene groups bonded at the para positions

The number of methylene groups bonded to the aromatic ring in one molecule of the novolac type phenol resin used in the present invention and the bonding form thereof were identified by known and commonly used methods. Each absorption position and intensity can be confirmed in advance using a standard substance, and the absorption position and absorption intensity can be determined. Examples of the known and commonly used methods include methods using infrared absorption spectrum, nuclear magnetic resonance spectrum, gel permeation chromatography and the like.

By using a novolac type phenol resin or a phenol dicyclopentadiene resin having an O / P ratio of 3 or more, the solubility in the compound (C) having at least two ethylenically unsaturated double bonds described later is improved. It is possible to obtain a cured product which is favorable and has little variation in quality such as strength. Further, by using the novolac type phenol resin having an ethylenically unsaturated double bond in the molecule, the reactivity with the compound (C) having at least two ethylenically unsaturated double bonds described later is high, and the curing rate is high. Get faster

When two or more kinds of novolak type phenolic resins having different O / P ratios are mixed and used, the total O
It can be used so that the / P ratio becomes 3 or more.
As the novolac type phenolic resin, one having an O / P ratio as high as possible is preferable, and among them, the O / P ratio is 4 to 7
Those in the range of are particularly preferable. As the novolac type phenolic resin, any of those which are generally referred to as “high ortho novolac type phenolic resin” and which are commercially available can be used. Hereinafter, a novolac type phenol resin having an O / P ratio of 3 or more is referred to as a high ortho novolac type phenol resin.

The novolac type phenolic resin obtained by the reaction of the phenolic compound and the formaldehyde supplying substance is
Not only those having a structure in which a phenolic compound is bonded only by a methylene group, but also those having a structure having both a methylene group and a dimethylene ether group and being bonded by them.

The number average molecular weight of the novolac type phenol resin or phenol dicyclopentadiene resin (B) used in the present invention is not particularly limited, but is preferably in the range of 200 to 2,000, particularly preferably. It is in the range of 300 to 1,000. Number average molecular weight is 20
When it is in the range of 0 to 2,000, the solubility in the compound (C) having at least two ethylenically unsaturated double bonds is improved.

The method for producing the novolac type phenol resin is not particularly limited, and a known and commonly used method can be adopted. That is, such a novolak type phenol resin is obtained by, for example, adding a formaldehyde supply substance and a phenol compound in the presence of an acid catalyst to formaldehyde supply substance / phenol compound = 0.7 to 1.0.
It can be easily obtained by carrying out an addition condensation reaction in a molar ratio. The high ortho novolac type phenolic resin can be obtained, for example, by subjecting it to an addition condensation reaction in the presence of a weakly acidic catalyst such as zinc acetate as described later.

The phenol dicyclopentadiene resin is, for example, a mixture of dicyclopentadiene and a phenolic compound in the presence of an acid catalyst in a molar ratio of dicyclopentadiene / phenolic compound = 1: 0.05 to 1: 15.0. It can be easily obtained by reacting so that The phenol dicyclopentadiene resin thus obtained can be used as it is, but distilling off unreacted phenolic compounds and dicyclopentadiene by distillation under reduced pressure improves the heat resistance of the cured product. Is preferred.

As the phenolic compound, any of the known compounds can be used. For example, phenol, bisphenol F, bisphenol A and bisphenol A can be used.
Bisphenols such as F; cresol, xylenol,
Alkyl-substituted phenols such as p-tert-butylphenol; halogenophenols such as bromophenol; aromatic hydrocarbons containing two or more phenolic hydroxyl groups such as resorcin; 1-naphthol, 2-naphthol, 1,6-dihydroxy Examples thereof include naphthols such as naphthalene and 2,7-dihydroxynaphthalene. These phenolic compounds may be used alone or as a mixture of two or more kinds.

Raw materials for the above-mentioned high ortho novolac type phenol resin include phenol, m-cresol,
1,5-xylenol, which is a compound having no substituent other than at least the meta position with respect to the phenolic hydroxyl group
One species or two or more species are used.

If necessary, furfural, urea, melamine, acetoguanamine, benzoguanamine and the like may be used in combination with the phenolic compound. As the above-mentioned formaldehyde supplying substance, any known substance can be used, for example, an aqueous formaldehyde solution,
Paraformaldehyde etc. are mentioned.

The catalyst used for producing the novolac type phenol resin is not particularly limited, but examples thereof include metal salts such as oxalic acid, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, phosphoric acid, zinc acetate and manganese borate. , And metal oxides such as lead oxide and zinc oxide. In order to obtain the above-mentioned high ortho novolac type phenol resin, metal salts such as zinc acetate and manganese borate and metal oxides such as lead oxide and zinc oxide are preferable. Examples of the catalyst used for producing the phenoldicyclopentadiene resin include Lewis acid catalysts such as aluminum chloride, boron trifluoride, zinc chloride, sulfuric acid and titanium chloride.

The novolac type phenolic resin having an ethylenically unsaturated double bond in the above molecule is obtained by adding an ethylenically unsaturated double bond to an ordinary phenolic compound having no ethylenically unsaturated double bond. It can be obtained by using together a phenolic compound having at least one bond.

The above-mentioned phenolic compound having at least one ethylenically unsaturated double bond is not particularly limited, but for example, arylphenol (o
-, M- or p-), vinylphenol (o-, m-
Or p-), propenylphenol (o-, m- or p-), isopropenylphenol (o-, m- or p-), arylresorcinol, diarylresorcinol, arylcatechol, diarylcatechol, arylhydroquinone, diarylhydroquinone,
Aryl pyrogallol etc. are mentioned. Of these,
Arylphenols are preferred.

The reaction between the above-mentioned phenolic compound and the formaldehyde supplying substance, and the reaction between the phenolic compound and dicyclopentadiene may be carried out in the presence of an organic solvent or may be carried out in the absence of the organic solvent. An organic solvent may be added to the obtained reaction product. In order to obtain the high ortho novolac type phenol resin in the former reaction, it is preferable to carry out the reaction in the presence of an organic solvent.

The organic solvent is not particularly limited,
Examples include aromatic hydrocarbons such as toluene and xylene. The reaction may be carried out in a batch kettle,
It may also be carried out in a tubular reactor with static mixing elements.

As the novolac type phenol resin or phenol dicyclopentadiene resin (B) used in the present invention, the amount of residual metal salt or metal oxide used as a catalyst in the production is as small as possible, particularly 0.005 p.
It is preferable to use one having a pm or less. If these metal compounds or the like remain, the curing catalyst described below is consumed by the remaining metal compounds, which is not preferable.
As a method for reducing the residual amount of the catalyst, any known and commonly used method can be adopted, but usually, the method of repeating washing with water is the easiest and preferable.

The compound (C) having at least two ethylenically unsaturated double bonds used in the present invention is not particularly limited, and examples thereof include divinylbenzene, alkyldivinylbenzene and halogen-substituted compounds thereof.
Having at least one phenolic hydroxyl group such as triarylphenol, trivinylphenol, tripropenylphenol, triisopropenylphenol, triarylresorcinol, trivinylresorcinol,
Moreover, the compound etc. which have at least 3 ethylenically unsaturated double bonds are mentioned. Among the above compounds, in consideration of reactivity and workability, a compound having at least one divinylbenzene and a phenolic hydroxyl group and at least three ethylenically unsaturated double bonds is preferable, and particularly divinylbenzene. Is preferred. Among the compounds having at least one phenolic hydroxyl group and at least three ethylenically unsaturated double bonds, triarylphenol is particularly preferable.

At least 2 ethylenically unsaturated double bonds
As the compound (C) having the individual compounds, the above compounds can be used alone or in combination of two or more kinds. In addition to the above compounds, the compound (C) may further contain a compound having one ethylenically unsaturated double bond. Examples of the compound having one ethylenically unsaturated double bond include aromatic monovinyl compounds such as ethylbenzene, styrene, methylstyrene, ethylstyrene, and monobromostyrene, (meth) acrylic acid methyl ester,
Examples thereof include aliphatic monovinyl compounds such as (meth) acrylic acid stearyl ester, (meth) acrylic acid N-methylol (meth) acrylamide, and γ-mercaptopropyltrimethoxysilane.

The compounding ratio of the novolac type phenol resin or phenol dicyclopentadiene resin (B) used in the present invention and the compound (C) having at least two ethylenically unsaturated double bonds is such that the phenol resin (B) and Although it depends on the kind of the compound (C), it is usually (B)
The range of / (C) = 70/30 to 40/60 weight ratio is preferable. When the (B) / (C) weight ratio is in the above range, the obtained resin composition has appropriate viscosity and solubility, and a cured product having high performance such as strength can be obtained.

A mixture of the conductive material (A), a novolac type phenol resin or a phenol dicyclopentadiene resin (B) and a compound (C) having at least two ethylenically unsaturated double bonds is subjected to a molding step. As a result, the phenol resin (B) and the compound (C) having at least two ethylenically unsaturated double bonds add and undergo a crosslinking reaction.

A curing catalyst (D) can be added to the above mixture for the purpose of accelerating the addition crosslinking reaction. Examples of the curing catalyst (D) include metal chlorides such as aluminum chloride and stannous chloride; inorganic acids such as sulfuric acid, hydrochloric acid and phosphoric acid; organic sulfonic acids such as benzenesulfonic acid and p-toluenesulfonic acid; acetic acid. , Organic carboxylic acids such as oxalic acid and maleic acid; halides thereof; sulfonates derived from novolac type phenolic resins and the like. Among these, organic sulfonic acids are preferable because they can be easily dissolved uniformly in the mixture and the curing rate can be easily adjusted.

The amount of the above-mentioned curing catalyst (D) used is not particularly limited, but is usually 0.1 with respect to the above mixture.
˜5.0 wt% is preferred.

As the curing catalyst (D), in addition to the above compounds, phosphite such as monophenyl phosphite, esters derived from sulfuric acid or organic sulfonic acid, such as p
-A latent catalyst such as methyl toluenesulfonate, a salt such as ammonium chloride, various onium salts represented by sulfonium salts, that is, a catalyst that decomposes to generate an acidic component under a certain temperature condition can be used. . The above curing catalyst may be used alone, or the curing catalyst and the latent catalyst may be mixed and used.

The fuel cell separator of the present invention comprises the above conductive material (A), a novolac type phenol resin or a phenol dicyclopentadiene resin (B) and a compound (C) having at least two ethylenically unsaturated double bonds. And a compound having at least two ethylenically unsaturated double bonds in which the conductive material (A) is a novolac-type phenol resin or phenol dicyclopentadiene resin (B). It is dispersed in a cured product of an addition crosslinking reaction with (C).

Such a fuel cell separator comprises the above conductive material (A), a novolac type phenol resin or phenol dicyclopentadiene resin (B), and a compound (C) having at least two ethylenically unsaturated double bonds. If necessary, the curing catalyst (D) is further kneaded, and the kneaded product is heat-molded to obtain the product.

The method of kneading the above-mentioned conductive material (A) with a novolac type phenol resin or phenol dicyclopentadiene resin (B) and a compound (C) having at least two ethylenically unsaturated double bonds, etc. There is no particular limitation, and ordinary industrial methods using a kneader, a stirrer, a mixer and the like can be mentioned. During the kneading, the mixture may be formed into a sheet shape, a block shape, or a particle shape in order to improve moldability and handleability of the mixture.

The above mixture can be easily molded by carrying out compression molding, transfer molding, injection molding or the like using a mold having a desired separator shape. The molding temperature can be appropriately selected, but in consideration of productivity, it is usually
The range of 140-190 degreeC is preferable. The shape of the fuel cell separator of the present invention is not particularly limited, and for example, as shown in FIG.
It is possible to use a shape having a gas or liquid supply path on both sides as shown in FIG.

The fuel cell separator of the present invention is preferably used in a fuel cell whose operating temperature during power generation is 200 ° C. or lower. Fuel cell separator of the present invention, hydrazine type, direct methanol type, alkaline type, solid polymer type,
It can be used as a separator for various types of fuel cells such as phosphoric acid type.

The fuel cell of the present invention has an electrolyte membrane, an electrode, and the above-mentioned fuel cell separator. The electrodes are placed in close contact with each other on both sides of the electrolyte membrane, and the electrodes are placed in close contact with each other. In the fuel cell, an electrolyte membrane has a laminated structural unit sandwiched between the fuel cell separators.

A fuel cell generally has a basic structure of a laminated structural unit (single cell) sandwiched between the above two separators. When high output is required, a plurality of single cells are laminated in series. The stack structure is adopted, and current is collected by current collector plates provided at both ends of this stack.

As the electrolyte, potassium hydroxide or the like is used in the case of hydrazine type or alkali type, ion exchange membrane or the like is used in the case of direct methanol type or solid polymer type, and phosphoric acid type is used. For example, phosphoric acid or the like is used.

The electrode comprises a fuel electrode and an oxidant electrode. Platinum, palladium, silver, nickel or the like is used as a material of the electrode, and carbon black or carbon fiber is supported on the surface thereof and used as necessary. As the fuel of the fuel electrode, hydrazine, methanol, hydrogen gas or the like can be used. Hydrogen gas can be obtained from hydrolyzate of water or hydrocarbons such as natural gas, petroleum, coal and methanol.
When an ion exchange membrane is used as the electrolyte, it is preferable to use a humidified fuel such as a mixed gas of hydrogen gas and water as the fuel.

As the oxidizing agent for the oxidizing agent electrode, hydrogen peroxide solution, air, oxygen gas, etc. can be used. Of these, air is preferable because it is easy to handle. When using an ion exchange membrane as the electrolyte,
It is preferred to use a humidified oxidant.

The separator of the present invention can be used as a separator for fuel cells of the above-mentioned type, but is particularly suitable for polymer electrolyte fuel cells.

The structure of a polymer electrolyte fuel cell using the fuel cell separator of the present invention will be described with reference to FIG. In this polymer electrolyte fuel cell, a cell 1 which is a basic constitutional unit of the fuel cell has separators 6 and 7 on both sides of an electrolyte membrane electrode assembly 5 comprising a solid polymer electrolyte membrane 2, a fuel electrode 3 and an oxidizer electrode 4. It has a structure sandwiched between. The flow path 8 formed on the surface of the separator is suitable for stably supplying the fuel and the oxidant to the electrode. Further, heat can be taken out from the fuel cell by introducing water as a heat medium into the surface of the separator installed on the oxidant electrode 4 side opposite to the oxidant electrode 4.
FIG. 3 shows an example of a cell stack in which a plurality of cells configured in this way are stacked in series.

[0058]

EXAMPLES The present invention will be described more specifically below with reference to Examples and Comparative Examples, but the present invention is not limited to these. In the following, all parts and% are based on weight unless otherwise specified.

The measuring method and evaluation criteria used in the present invention are described below. [Appearance of Molded Article] The fuel cell separator obtained in the Examples described later was used as a test piece as it was, and the test piece was visually observed for warpage, cracking, swelling, and internal state. warp,
With regard to cracking and swelling, those in which no occurrence was found in the test piece were designated as "none", and those in which even a little was found were designated as "present". Regarding the internal state, the cross section of the test piece was visually observed, and the one in a dense state was “good”, and the one in which a lot of voids were generated was “many voids”.

[Electrical Conductivity] A test piece having a width of 1 cm, a thickness of 4 mm and a length of 20 cm was cut out from the flat plate-shaped molded product obtained in the below-mentioned Examples, and this test piece was JIS C252.
According to 5, the volume resistivity was measured. When the test piece was cracked and the volume could not be measured correctly, it was designated as "unmeasurable".

[Flexural Strength] The flat plate-shaped molded articles obtained in the examples described below were used as test pieces as they were, and the flexural strength was measured according to JIS K-6911. The evaluation criteria of “unmeasurable” are the same as above.

Synthesis Example 1 A 4-necked 3 liter flask equipped with a stirrer, a condenser, a thermometer and a dropping funnel was charged with 940 g (10 mol) of phenol, 470 g of xylene and 281.3 g of 80% paraformaldehyde.
(7.5 mol) was added and stirring was started. As a catalyst, 4.7 g of zinc acetate dihydrate was added, and the temperature was raised to the reflux temperature. After refluxing xylene and water for 4 hours and reacting while removing only the outflowing water layer, distillation was started to remove residual water and xylene as a solvent, and the temperature was raised to 130 ° C. , 130 ° C. for 2 hours. 940g of water
The mixture was cooled to 80 ° C. and the stirring was stopped. The separated upper aqueous layer was withdrawn, water was further added, and zinc acetate as a catalyst was washed and separated by the same operation. Then, the resin layer was heated to remove residual moisture and heated to 170 ° C. After partially removing the free phenol at 170 ° C. under reduced pressure, the product was taken out from the reaction container to obtain a solid novolac type phenol resin.

When this resin was washed twice with water, the content of zinc acetate was 0.003 ppm. This was heated again to remove residual water, and a solid novolac type phenol resin was obtained. This resin has a softening point (ring and ball method) of 85 ° C. and a number average molecular weight of 852 (confirmed by GPC).
Then, it was confirmed by C ¹³ -NMR that the O / P ratio was 4.3. To 100 parts of this resin, 100 parts of divinylbenzene (purity 80%, containing ethylstyrene) was used and dissolved at 50 ° C. to obtain a resin solution. Paratoluene sulfonic acid 30% to 100 parts of this resin solution,
1.55 parts of a phenol solution was added and uniformly stirred to obtain a phenol resin solution. Hereinafter, this resin solution is referred to as a resin solution A.

<< Synthesis Example 2 >> 752 g (8 mol) of phenol, 268 g (2 mol) of o-arylphenol and 470 g of xylene and 8 were placed in a 4-necked 3 liter flask equipped with a stirrer, a condenser, a thermometer and a dropping funnel.
243.8 g (6.5 mol) of 0% paraformaldehyde
Was added and stirring was started. 4.7 g of zinc acetate dihydrate was added as a catalyst, and the temperature was raised to the reflux temperature. After refluxing xylene and water for 4 hours and reacting while removing only the outflowing water layer, distillation is started to remove residual water and xylene, which is a solvent, at 130 ° C. for 2 hours. Held
Water (940 g) was added, the mixture was cooled to 80 ° C., and stirring was stopped. The separated upper aqueous layer was removed, water was further added, and zinc acetate as a catalyst was washed and separated by the same operation. After that, the resin layer is heated to remove residual moisture, and
The temperature was raised to 0 ° C. After partially removing free phenol at 170 ° C. under reduced pressure, it was taken out from the reaction vessel to obtain a solid novolac resin having a softening point (ring and ball method) of 65 ° C. and a number average molecular weight of 723 (confirmed by GPC). It was confirmed by C ¹³ -NMR that the O / P ratio was 4.9. 100 parts of this novolac type phenol resin is added to 80 parts of divinylbenzene (purity 80%, containing ethylstyrene) at 50 ° C.
Was dissolved in to obtain a resin solution. To 100 parts of this resin solution, 1 part of xylene sulfonic acid was added and uniformly stirred to obtain a resin solution. Hereinafter, this resin solution is referred to as a resin solution B.

<< Synthesis Example 3 >> Special phenol resin DPP-
100 parts of 3H [phenol dicyclopentadiene resin, manufactured by Nippon Petrochemical Co., Ltd.] was added to divinylbenzene (purity 80
%, Containing ethyl styrene) at 50 ° C. to obtain a resin solution. To 100 parts of this resin solution, 1 part of xylene sulfonic acid was added and uniformly stirred to obtain a resin solution. Hereinafter, this resin solution is referred to as a resin solution C.

Examples 1 to 10 Fuel cells prepared by synthesizing Examples 1 to 3 were mixed with the resin solutions A to C and the conductive materials at the compounding composition ratios shown in Table 1-1, and then heated to 150 ° C. Fill uniformly into the separator shape mold and flat plate mold,
Using a compression molding machine, molding was carried out under the conditions of a pressure of 100 kg / cm ² (gauge pressure) and a molding time of 30 minutes to produce a fuel cell separator and a flat plate molded product having a width of 20 cm, a thickness of 4 mm and a length of 20 cm. The appearance of the fuel cell separator was evaluated, and the electrical conductivity and bending strength of the flat plate molded product were evaluated. The evaluation results are shown in Table 2.

Comparative Example 1 Resin Solution A in Example 1
Was replaced with Phenolite J-375 [a general-purpose novolac-type phenol resin containing hexamethylenetetramine as a curing agent, manufactured by Dainippon Ink and Chemicals, Inc.], and molded under the same conditions as in Example 1 to obtain The appearance, conductivity, and bending strength of the fuel cell separator and the flat molded article were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Comparative Example 2 Resin Solution A in Example 1
Was changed to Phenolite J-325 [general-purpose resol type phenolic resin, manufactured by Dainippon Ink and Chemicals, Inc.], and the obtained fuel cell separator and flat plate-shaped molded article were molded in the same manner as in Example 1. An evaluation was made. The evaluation results are shown in Table 2.

[0069]

[Table 1]

[0070]

[Table 2]

[0071]

[Table 3]

[0072]

[Table 4]

[0073]

The fuel cell separator of the present invention is excellent in conductivity, gas impermeability and mechanical strength, is free from warpage, cracking and swelling, is excellent in dimensional accuracy, and has a good internal condition. It is a thing. Further, according to the method for producing a fuel cell separator of the present invention, conductivity, gas impermeability, mechanical strength is excellent, warpage, cracking, swelling, etc. do not occur, dimensional accuracy is excellent, and the internal state is also good. A simple fuel cell separator can be produced economically and stably. Further, the fuel cell obtained by the present invention is a high performance fuel cell.

[Brief description of drawings]

FIG. 1 is a perspective view showing a fuel cell separator according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a fuel cell structure according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a fuel cell stack structure according to an embodiment of the present invention.

[Explanation of symbols]

1 cell 2 Solid polymer electrolyte membrane 3 fuel pole 4 oxidizer poles 5 Electrolyte membrane electrode assembly 6 separator 7 separator 8 channels

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 19, 2002 (2002.9.1)
9)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

The above-mentioned phenolic compound having at least one ethylenically unsaturated double bond is not particularly limited, but for example, allylphenol (o
-, M- or p-), vinylphenol (o-, m-
Or p-), propenyl phenol (o-, m-or p-), isopropenylphenol (o-, m-or p-), allyl resorcinol, diallyl resorcinol <br/> Lumpur, allyl catechol, diallyl catechol, allyl <br/> hydroquinone, diallyl hydroquinone, allyl pyrogallol <br/> Lumpur, and the like. Of these, allylphenol is preferred.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction content]

As the novolac type phenol resin or phenol dicyclopentadiene resin (B) used in the present invention, the amount of residual metal salt or metal oxide used as a catalyst in the production is as small as possible, particularly 0.005 p.
It is preferable to use one having a pm or less. If these metal compounds or the like remain, the curing catalyst described below is consumed by the remaining metal compounds, which is not preferable.
As a method for reducing the residual amount of the metal compound, any known and commonly used method can be adopted, but a method of repeating washing with water is usually the easiest and preferable.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

The compound (C) having at least two ethylenically unsaturated double bonds used in the present invention is not particularly limited, and examples thereof include divinylbenzene, alkyldivinylbenzene and halogen-substituted compounds thereof.
Triallyl phenol, tri-vinylphenol, tri propenyl phenol, tri isopropenylphenol,
Examples thereof include compounds having at least one phenolic hydroxyl group and at least three ethylenically unsaturated double bonds such as triallyl resorcinol and trivinyl resorcinol. Among the above compounds, in consideration of reactivity and workability, a compound having at least one divinylbenzene and a phenolic hydroxyl group and at least three ethylenically unsaturated double bonds is preferable, and particularly divinylbenzene. Is preferred. Having at least one of the above phenolic hydroxyl group, and triallyl Fe <br/> Nord in ethylenically unsaturated double bonds at least three having compounds are particularly preferred.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0062

[Correction method] Change

[Correction content]

Synthesis Example 1 A four-necked 3-liter flask equipped with a stirrer, condenser, thermometer and dropping funnel was charged with 940 g (10 mol) of phenol, 470 g of xylene and 281.3 g of 80% paraformaldehyde.
(7.5 mol) was added and stirring was started. 4.7 g of zinc acetate dihydrate was added as a catalyst, and the temperature was raised to the reflux temperature. After refluxing xylene and water for 4 hours and reacting while removing only the outflowing water layer, distillation was started to remove residual water and xylene as a solvent, and the temperature was raised to 130 ° C. , 130 ° C. for 2 hours. 940g of water
The mixture was cooled to 80 ° C. and the stirring was stopped. The separated upper aqueous layer was withdrawn, water was further added, and zinc acetate as a catalyst was washed and separated by the same operation. Then, the resin layer was heated to remove residual moisture and heated to 170 ° C. After partially removing the free phenol at 170 ° C. under reduced pressure, the product was taken out from the reaction container to obtain a solid novolac type phenol resin.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Change

[Correction content]

When this resin was washed twice with water, the content of zinc acetate was 0.003 ppm. This was heated again to remove residual water, and a solid novolac type phenol resin was obtained. This resin has a softening point (ring and ball method) of 85 ° C. and a number average molecular weight of 852 (confirmed by GPC).
Then, it was confirmed by C ¹³ -NMR that the O / P ratio was 4.3. To 100 parts of this resin, 100 parts of divinylbenzene (purity 80%, containing ethylstyrene) was used and dissolved at 50 ° C. to obtain a resin solution. Paratoluenesulfonic acid 30% to 100 parts of this resin solution
1.55 parts of the phenol solution of was added and stirred uniformly to obtain a phenol resin solution. Hereinafter, this resin solution is referred to as a resin solution A.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0064

[Correction method] Change

[Correction content]

[0064] "Synthesis Example 2" stirrer, a condenser, a four-necked 3-liter flask was equipped with a equipped with a thermometer and a dropping funnel, a phenol 752 g (8 mol), o-allyl phenol <br/> Lumpur 268 g (2 moles) And 470 g xylene and 80
% Paraformaldehyde 243.8 g (6.5 mol) was added and stirring was started. 4.7 g of zinc acetate dihydrate was added as a catalyst, and the temperature was raised to the reflux temperature. After refluxing xylene and water for 4 hours and reacting while removing only the outflowing water layer, distillation is started to remove residual water and xylene, which is a solvent, at 130 ° C. for 2 hours. Held
Water (940 g) was added, the mixture was cooled to 80 ° C., and stirring was stopped. The separated upper aqueous layer was removed, water was further added, and zinc acetate as a catalyst was washed and separated by the same operation. After that, the resin layer is heated to remove residual moisture, and
The temperature was raised to 0 ° C. After partially removing free phenol at 170 ° C. under reduced pressure, it was taken out from the reaction vessel to obtain a solid novolac resin having a softening point (ring and ball method) of 65 ° C. and a number average molecular weight of 723 (confirmed by GPC). It was confirmed by C ¹³ -NMR that the O / P ratio was 4.9. 100 parts of this novolac type phenol resin is added to 80 parts of divinylbenzene (purity 80%, containing ethylstyrene) at 50 ° C.
Was dissolved in to obtain a resin solution. To 100 parts of this resin solution, 1 part of xylene sulfonic acid was added and uniformly stirred to obtain a resin solution. Hereinafter, this resin solution is referred to as a resin solution B.

Continued front page    (72) Inventor Kenichi Hamada             1-18-32-101 Inttori-cho, Izumiotsu City, Osaka Prefecture (72) Inventor Masayuki Kamei             5-5-406 Shin-Kanaoka Town, Sakai City, Osaka Prefecture F-term (reference) 4F071 AA22 AA30 AA41 AB03 AB06                       AE15 AH15 BB03 BC01                 4J026 AB01 AC00 BA07 BA17 BB01                       DB05 GA06                 5H026 AA06 AA08 BB01 BB08 EE18                       HH00 HH05 HH08

Claims (14)

[Claims] 1. A fuel cell separator comprising a conductive material (A), wherein the conductive material (A) comprises a novolac type phenol resin or a phenol dicyclopentadiene resin (B) and an ethylenically unsaturated double bond. At least 2
A fuel cell separator, characterized in that it is dispersed in a cured product of an addition-crosslinking reaction with a compound (C) having a unit. 2. A novolac type phenol resin, wherein a bond of a methylene group to an aromatic ring contained in one molecule of the phenol resin is bonded to an ortho position with respect to the number bonded to a para position with respect to a phenolic hydroxyl group. The fuel cell separator according to claim 1, which is a novolac-type phenol resin having a ratio of 3 or more. 3. The fuel cell separator according to claim 1, wherein the novolac type phenolic resin has an ethylenically unsaturated double bond in the molecule. 4. The fuel cell separator according to claim 1, wherein the novolac type phenolic resin has a number average molecular weight in the range of 200 to 2,000. 5. The fuel cell separator according to claim 1, wherein the phenol dicyclopentadiene resin has a number average molecular weight in the range of 200 to 2,000. 6. The fuel cell separator according to claim 1, wherein the compound (C) having at least two ethylenically unsaturated double bonds is divinylbenzene. 7. The ratio of the novolac type phenol resin or phenol dicyclopentadiene resin (B) to the compound (C) having at least two ethylenically unsaturated double bonds is (B) / (C) = 70 / The fuel cell separator according to claim 1, which has a weight ratio of 30 to 40/60. 8. The fuel cell separator according to claim 1, which is used in a fuel cell having an operating temperature of 200 ° C. or less during power generation. 9. A conductive material (A) is kneaded with a novolac type phenol resin or a phenol dicyclopentadiene resin (B) and a compound (C) having at least two ethylenically unsaturated double bonds, and then obtained. A method for producing a fuel cell separator, which comprises heat-molding a kneaded product. 10. A conductive material (A), a novolac type phenol resin or a phenol dicyclopentadiene resin (B), a compound (C) having at least two ethylenically unsaturated double bonds, and a curing catalyst (D). A method for producing a fuel cell separator, which comprises kneading and then kneading the obtained kneaded product. 11. A novolac-type phenol resin, wherein the bond of a methylene group to an aromatic ring contained in one molecule of the phenol resin is bonded to the ortho position with respect to the number bonded to the phenolic hydroxyl group in the para position. The novolac type phenolic resin having a ratio of the number of the present is 3 or more.
0. A method for producing a fuel cell separator according to 0. 12. The method for producing a fuel cell separator according to claim 9, wherein the compound (C) having at least two ethylenically unsaturated double bonds is divinylbenzene. 13. The novolac type phenol resin has an ethylenically unsaturated double bond in the molecule.
0. A method for producing a fuel cell separator according to 0. 14. An electrolyte membrane, an electrode, and the fuel cell separator according to any one of claims 1 to 8, wherein the electrode is closely attached to both surfaces of the electrolyte membrane, and the electrode is A fuel cell having a laminated structure in which electrolyte membranes arranged in close contact are sandwiched between the fuel cell separators.