JP5987775B2 - Catalyst paste composition for fuel cell, catalyst ink composition, catalyst layer or water repellent layer, electrode membrane assembly, fuel cell - Google Patents

Description

  The present invention relates to a catalyst paste composition and a catalyst ink composition for a fuel cell, and relates to a catalyst layer or a water repellent layer, an electrode membrane assembly and a fuel cell using them.

  A fuel cell is a system that can directly convert chemical energy into electrical energy using an electrochemical system, and is expected to be a next-generation energy because of its high efficiency. In particular, solid polymer fuel cells are being actively developed for automobiles, stationary devices, and small mobile devices. Conventionally, platinum-based catalysts using platinum or platinum alloys having high oxygen reduction activity have been used as electrode catalysts for these polymer electrolyte fuel cells, but from the viewpoint of cost, resource amount, and supply stability Development of catalysts other than platinum-based catalysts (referred to as non-platinum-based catalysts) has been demanded. However, the performance of current non-platinum-based catalysts is not sufficient compared to platinum-based catalysts, so technological development of catalysts that significantly reduce the amount of platinum used or non-platinum-based catalysts that do not use platinum has been promoted. Yes. (Non-Patent Document 1, Patent Documents 1-3, etc.)

  As such a non-platinum-based catalyst, for example, Patent Document 2 proposes a carbon material obtained by doping nitrogen into a carbonized product obtained by mixing a carbon additive with a polymer metal complex and performing heat treatment. Such a carbon material doped with nitrogen can be used as a non-platinum-based catalyst having oxygen reduction activity. Patent Document 3 proposes that a carbon material obtained by introducing an ion-exchange functional group into a surface-treated carbon material by a grafting reaction can be used as a non-platinum catalyst.

  Non-platinum-based catalysts are more economically and cost-effective than platinum-based catalysts, and are actively being developed. However, compared to platinum, their performance is still not sufficient, and when platinum is used. In order to obtain battery performance close to, it is necessary to increase the thickness of the catalyst layer and increase the amount of catalyst particles in the catalyst layer. In addition, when a non-platinum-based catalyst is dispersed to form a composition, the non-platinum-based catalyst is likely to cause aggregation, so that it is necessary to improve the dispersion stability in the composition. Also, when these compositions are applied, if the catalyst agglomerates, pinholes are formed in the coating film, or a suitable electrode film cannot be obtained, resulting in a decrease in the amount of current and a decrease in electromotive force. There is a problem. Although there is such a technical problem, no means for solving this has been found.

JP 2011-6283 A JP 2008-282725 A JP 2009-295441 A

SCIENCE (VOL.332, pp.443-447, 2011)

  The problem to be solved by the present invention is a catalyst paste composition and a catalyst ink composition for fuel cells, which have good dispersibility and low viscosity of non-platinum-based carbon-based catalyst materials, and have storage stability and coating properties. Is to provide. In addition, by using these compositions, a fuel cell catalyst layer with very little coating unevenness and pinholes when applied, and a fuel cell electrode membrane assembly having the same, and excellent battery performance A fuel cell is provided.

As a result of intensive studies to solve the above problems, the present inventors have reached the present invention.
The first invention relates to a fuel cell catalyst paste composition comprising a resin represented by the general formula (1) and a non-platinum-based carbon-based catalyst material.
The second invention is characterized in that the resin is obtained by reacting a polyvinyl alcohol resin (a) or a polyvinyl acetal resin (b) with a compound represented by the general formula (3) or the general formula (4). The present invention relates to a catalyst paste composition for a fuel cell.
According to a third aspect of the invention, the fuel cell catalyst is characterized in that the resin is obtained by reacting a polyvinyl alcohol resin (a) or a polyvinyl acetal resin (b) with a compound represented by the general formula (3). The present invention relates to a paste composition.
A fourth invention relates to the fuel cell catalyst paste composition, wherein the resin is obtained by reacting a polyvinyl acetal resin (b) with a compound represented by the general formula (3).
A fifth invention relates to a fuel ink catalyst ink composition comprising the fuel cell catalyst paste composition and at least one of a proton conductive polymer and a water repellent material.
The sixth invention relates to a fuel cell catalyst layer or a fuel cell water repellent layer formed from the fuel cell catalyst ink composition.
A seventh invention relates to a fuel cell electrode membrane assembly comprising a solid polymer electrolyte membrane, at least one of the fuel cell catalyst layer or the fuel cell water repellent layer, and a gas diffusion layer.
An eighth invention relates to a fuel cell comprising the fuel cell electrode membrane assembly.

  According to the present invention, there are provided a fuel cell catalyst paste composition and a catalyst ink composition that have good dispersibility of the non-platinum-based carbon-based catalyst material, low viscosity, excellent storage stability, and coating properties. Therefore, by using these compositions, the fuel cell catalyst layer having extremely low coating unevenness and pinholes when applied, and the fuel cell electrode membrane assembly having the same are provided. Can be obtained. Therefore, it is possible to provide a fuel cell with excellent battery performance.

  Hereinafter, the present invention will be described in detail. In this specification, “catalyst paste composition for fuel cell” is referred to as “catalyst paste composition” or “paste composition”, and “catalyst ink composition for fuel cell” is referred to as “catalyst ink composition” or “ink. Sometimes referred to as “composition”. Further, the “fuel cell catalyst paste composition” and the “fuel cell catalyst ink composition” may be simply referred to as “composition”. Further, “resin” is sometimes referred to as “polymer”.

<Catalyst paste composition for fuel cell>
The paste composition of the present invention contains at least a non-platinum carbon-based catalyst material and a resin, and preferably further contains a solvent. The proportions of the non-platinum-based carbon-based catalyst material, the resin, and the solvent are not particularly limited, and can be appropriately selected within a wide range.

  The resin content is preferably 0.01 to 25% by weight, more preferably 0.02 to 10% by weight, based on the non-platinum-based carbon-based catalyst material in the catalyst paste composition. By setting the content in this range, the dispersion stability of the non-platinum-based carbon-based catalyst material can be sufficiently achieved, and at the same time, aggregation of the non-platinum-based carbon-based catalyst material can be effectively prevented, and the catalyst layer surface can be obtained. Precipitation of the resin can be prevented.

  Further, the solvent is preferably 60 to 99 parts by weight, more preferably 65 to 97% by weight, when the catalyst paste composition is 100% by weight.

<Non-platinum-based carbon-based catalyst material>
A non-platinum-based carbon-based catalyst material (hereinafter also referred to as a carbon-based catalyst material) is a multi-component system mainly composed of aggregates of carbon (C) atoms, and is physically and chemically between these constituent units. A catalyst material having an interaction (bonding) and containing a heteroatom such as nitrogen (N), boron (B), phosphorus (P) or a transition metal such as a transition metal may be used. it can.
The inclusion of a heteroatom and a transition metal is important for having oxygen reduction activity. In general, in the case of a carbon-based catalyst material, as a catalyst active point, for example, in a structure (referred to as transition metal-N4 structure) in which, for example, four nitrogens are arranged on a plane centering on the surface of the carbon material. Transition metals, carbon atoms in the vicinity of hetero atoms introduced at the edge of the carbon material surface, and the like, and also in the carbon-based catalyst material of the present invention, the presence of hetero atoms and transition metal elements is important.
Such a carbon-based catalyst material has an oxygen reduction catalytic ability similarly to a conventionally known carbon material carrying platinum, and can be suitably used as an electrode catalyst for a fuel cell. The carbon-based catalyst material can be used for both the cathode and the anode, but is often used as the cathode.

  In the carbon-based catalyst material according to the present invention, when the doping amount of nitrogen or boron (the content of nitrogen or boron in the carbon-based catalyst material) is 0.1 to 40 mol%, respectively, oxygen reduction is good. Electrode activity. Further, when nitrogen and boron are simultaneously doped, a higher electrode activity is exhibited due to the interaction between the two. When both nitrogen and boron are doped, the atomic ratio (B / N) is 0.2 to 0.4, preferably 0.06 to 1.5, and the molar ratio ((B + N) / C) is preferably 0.03 to 0.4. Within these ranges, a highly active carbon-based catalyst material can be obtained.

<Carbon material>
The carbon material that is the main component of the carbon-based catalyst material in the present invention includes carbon black (furnace black, acetylene black, ketjen black, medium thermal carbon black), activated carbon, graphite, carbon nanotube, carbon nanofiber, and carbon nanohorn. , Graphene nanoplatelet, nanoporous carbon, carbon fiber and the like. Carbon materials have various physical properties and costs such as particle diameter, shape, BET specific surface area, pore volume, pore diameter, bulk density, DBP oil absorption, surface acidity, surface hydrophilicity, and conductivity depending on the type and manufacturer. Because it is different, select the most suitable material according to the intended use and required performance.

Examples of commercially available carbon materials include:
Ketjen Black made by Akzo, such as Ketjen Black EC-300J and EC-600JD;
Furnace blacks manufactured by Tokai Carbon, such as Toka Black # 4300, # 4400, # 4500, and # 5500;
Furnace Black made by Degussa such as Printex L;
Raven 7000, 5750, 5250, 5000 ULTRA III, 5000 ULT
Furnace black made by Colombian, such as RA, Conductex SC ULTRA, 975 ULTRA, PUER BLACK100, 115, and 205;
# 2350, # 2400B, # 2600B, # 30050B, # 3030B, # 3230B, # 3350B, # 3400B, and # 5400B furnace black manufactured by Mitsubishi Chemical Corporation;
Furnace black from Cabot, such as MONARCH 1400, 1300, 900, Vulcan XC-72R, and Black Pearls 2000;
Furnace black manufactured by TIMCAL, such as Ensaco 250G, Ensaco 260G, Ensaco 350G, and SuperP-Li;
Acetylene black manufactured by Denki Kagaku Kogyo Co., Ltd. such as Denka Black, Denka Black HS-100 and FX-35
Carbon nanotubes manufactured by Showa Denko KK such as VGCF, VGCF-H, VGCF-X;
Carbon nanotube manufactured by Meijo Nanocarbon
graphene nanoplatelets made by XGSciences such as xGnP-C-750, xGnP-M-5;
Nano-carbon produced by Easy-N;
Carbon fiber manufactured by Gunei Chemical Industry Co., Ltd., such as Kynol carbon fiber and Kynol activated carbon fiber;
However, it is not limited to these.

<Dope raw materials for heteroatoms and transition metals>
As a carbon-based catalyst material in the present invention, as a raw material used when doping a heteroatom such as nitrogen or boron or a transition metal, any material containing a heteroatom and / or a transition metal can be used. Any organic compound (pigment, polymer, etc.) and inorganic compound (metal simple substance, metal oxide, metal salt, etc.) can be used. The transition metal preferably contains at least one selected from cobalt, iron, nickel, manganese, copper, titanium, vanadium, chromium, zinc, tin, aluminum, and magnesium.
Among these, phthalocyanine compounds, naphthalocyanine compounds, porphyrin compounds, tetraazaannulene compounds, etc., which are nitrogen-containing aromatic compounds and can contain transition metals in the molecule, are contained in carbon-based catalyst materials. It is preferable because it is easy to dope nitrogen and transition metal efficiently. In addition, the aromatic compound has no problem even if an electron-withdrawing functional group or an electron-donating functional group is introduced. In particular, phthalocyanine compounds are particularly preferable as raw materials because there are compounds containing various transition metals and they are inexpensive, and among them, cobalt phthalocyanine compounds, nickel phthalocyanine compounds, iron Since phthalocyanine compounds are known to have high oxygen reduction activity, carbon-based catalyst materials synthesized from them are more preferable because they are inexpensive and have high oxygen reduction activity. .

(a) Production method of carbon-based catalyst material doped with nitrogen To produce a carbon-based catalyst material doped with nitrogen, first, as a nitrogen source, phthalocyanine, acrylonitrile, EDTA (ethylenediaminetetraacetic acid), melamine, etc. And a precursor of a thermosetting resin such as a furan resin or a phenol resin are mixed and reacted by heating to obtain a nitrogen compound-containing thermosetting resin.

  For example, when phthalocyanine is used as the nitrogen-containing compound and furfuryl alcohol is used as the thermosetting resin precursor, an acid such as hydrochloric acid is added to these mixtures, and the temperature is preferably in the range of 80 to 200 ° C. The phthalocyanine-containing furan resin, which is a nitrogen compound-containing thermosetting resin, can be obtained by heating and polymerizing. In order to make the nitrogen doping amount 0.1 to 40 mol%, the mixing ratio of furfuryl alcohol and melamine or phthalocyanine is C: N (molar ratio) 1: (0.07-3), preferably Is 1: (0.1 to 0.5).

  Next, the obtained phthalocyanine-containing furan resin is heat-treated at a predetermined temperature in an inert gas atmosphere such as nitrogen or helium to be carbonized. The heat treatment temperature is not particularly limited as long as it can be carbonized, but a preferable temperature is 400 to 1500 ° C, and a more preferable temperature is 500 to 1200 ° C. Subsequently, a carbon-based catalyst material having an average particle diameter of 45 μm or less, preferably 0.1 μm or less doped with nitrogen can be obtained by pulverizing preferably with a disperser such as a planetary ball mill.

  As another method for producing a carbon-based catalyst material doped with nitrogen, acetylene black, ketjen black, furnace black, graphene, carbon nanotubes, conductive carbon fibers, activated carbon, etc. are used as carbon materials, and nitrogen atoms are changed. It can obtain by mixing with the compound which has and heat-processing at predetermined | prescribed temperature similarly to the above, and carbonizing. At this time, the above carbon materials may be used alone, or some of them may be used after being mixed.

(b) Method for Producing Boron-Doped Carbon-Based Catalyst Material To produce a boron-doped carbon-based catalyst material, first, as a boron source, BF ₃ methanol complex or BF ₃ tetrahydrofuran (THF) complex, etc. The boron-containing compound and a precursor of a thermosetting resin such as a furan resin or a phenol resin are mixed and reacted by heating to obtain a boron compound-containing thermosetting resin.

For example, when BF ₃ methanol complex is used as the boron-containing compound and furfuryl alcohol is used as the precursor of the thermosetting resin, the polymerization reaction is preferably performed by heating at a temperature in the range of 80 to 200 ° C. Thus, a BF ₃ -containing furan resin can be obtained. In order to adjust the doping amount of boron atoms described above to 0.1 to 40 mol%, the mixing ratio of furfuryl alcohol and BF ₃ is 1: (0.1 to 1) in terms of C: B (molar ratio), preferably Is 1: (0.15-0.6).

Next, the obtained BF ₃ -containing furan resin is carbonized by heat treatment at the predetermined temperature described in (a) above under an inert gas atmosphere such as nitrogen or helium. Subsequently, a carbon-based catalyst material having an average particle diameter of 45 μm or less, preferably 0.1 μm or less doped with boron atoms can be obtained by pulverizing preferably with a ball mill such as a planetary ball mill.

(c) Method for producing carbon-based catalyst material doped with nitrogen and boron (thermal polymerization method)
In order to produce a carbon-based catalyst material doped with nitrogen and boron, first, a boron-containing compound and a nitrogen-containing compound are mixed with a precursor of a thermosetting resin such as a furan resin or a phenol resin, followed by a heating reaction. To obtain a boron-nitrogen compound-containing thermosetting resin.

For example, when BF ₃ methanol complex is used as the boron-containing compound, melamine is used as the nitrogen-containing compound, and furfuryl alcohol is used as the precursor of the thermosetting resin, the temperature is preferably in the range of 80 to 200 ° C. A BF ₃ -containing furan resin can be obtained by heating and causing a polymerization reaction. In order to make the doping amounts of nitrogen atom and boron atom 0.1 to 40 atom% and B / N atomic ratio 0.2 to 0.4, respectively, furfuryl alcohol, melamine and BF 3 methanol are used. The compounding ratio of the complex in terms of C: N: B (molar ratio) is 1: (0.04-2) :( 0.02-1), preferably 1: (0.3-0.7) :( 0. 4 to 1.5). Next, the obtained furan resin is carbonized at a predetermined temperature described in the above (a) under an inert gas atmosphere such as nitrogen or helium to obtain a carbon-based catalyst material doped with nitrogen and boron. Can do.

(d) Method for producing carbon-based catalyst material doped with nitrogen and boron (subcritical method)
As another method for producing a carbon-based catalyst material doped with nitrogen and boron, there is the following subcritical method. In this method, first, a nitrogen-containing compound and a boron-containing compound such as a BF ₃ methanol complex or a BF ₃ tetrahydrofuran (THF) complex as a boron source are dissolved in a solution of furfuryl alcohol or a resol type phenol resin. Perform a polymerization reaction.

For example, in the case of using a methanol solution of furfuryl alcohol, melamine as a nitrogen-containing compound, and BF ₃ methanol complex as a boron-containing compound, furfuryl is used under methanol subcritical or supercritical conditions at 200 to 350 ° C. Perform an alcohol polymerization reaction. In order to adjust the doping amounts of nitrogen and boron described above to 0.1 to 40 mol%, the mixing ratio of furfuryl alcohol, melamine, and BF ₃ methanol complex is 1 in C: N: B (molar ratio). : (0.2 to 0.8): (0.1 to 0.4), preferably 1: (0.3 to 0.7): (0.15 to 0.4). Next, by carbonizing the obtained polymer at a predetermined temperature described in the above (a) under an inert gas atmosphere such as nitrogen or helium, a carbon-based catalyst material doped with nitrogen and boron can be obtained. it can.

  The second form of the carbon-based catalyst material according to the present invention is a form in which carbon ultrafine particles having an average particle diameter of 10 to 100 nm produced by a sol-gel method are used as a precursor. Here, the ultrafine carbon particles are produced as follows. First, an aqueous solution containing a base catalyst such as phenol, formaldehyde and sodium carbonate is prepared. When this aqueous solution is kept at a predetermined temperature for a predetermined time to react phenol and formaldehyde, polymer ultrafine particles are generated in the reaction solution. The predetermined temperature is preferably 60 to 90 ° C, and more preferably 80 to 90 ° C. The predetermined time is preferably 1 to 20 hours, more preferably 8 to 18 hours. Next, the reaction solution is cooled to liquid nitrogen temperature, frozen, and dried to recover the ultrafine polymer particles. Further, the recovered polymer ultrafine particles are heated and cured at 100 to 250 ° C. for 0.5 to 10 hours, preferably at 200 to 230 ° C. for 3 to 6 hours. The cured ultrafine polymer particles are carbonized by heating under the carbonization heat treatment conditions described in the above (a) to obtain ultrafine carbon particles having an average particle size of 10 to 100 nm, preferably 10 to 30 nm. In order to obtain such ultrafine particles, the blending weight ratio of phenol, formaldehyde and sodium carbonate (phenol: formaldehyde: sodium carbonate) is 1: (1-2) :( 0.05-0.2), preferably 1: (1.4 to 1.6): (0.05 to 0.1).

<Resin>
The resin used in the present invention is represented by the following general formula (1). This resin mainly plays a role of favorably dispersing the carbon-based catalyst material in the solvent.

General formula (1)


R ¹ in the general formula (1) represents an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. A heteroaryl group which may have, or a group represented by the general formula (2), R ² is an alkyl group having 1 to 3 carbon atoms;
l = 0.0-99.8 mol%
m = 0.1-99.9 mol%
n = 0.1-30.5 mol%
o = 0.0-75.5 mol%
l + m + n + o = 100 mol%.

  The resin only needs to contain the four structural units represented by the general formula (1) within a limited range, and the arrangement of the structural units may be random.

Here, as the alkyl group which may have a substituent in R ¹ of the general formula (1), for example, a linear alkyl group (methyl, ethyl, n-propyl, n-butyl, n-pentyl, n -Octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, etc.), branched alkyl groups (isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl) , 2-ethylhexyl and 1,1,3,3-tetramethylbutyl), cyclic alkyl groups (cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.) and bridged cyclic alkyl groups (norbornyl, adamantyl, pinanyl, etc.). Preferably an alkyl group having 1 to 18 carbon atoms. A linear alkyl group having 1 to 18 carbon atoms is more preferable, and an octadecyl group is more preferable.

Examples of the alkenyl group which may have a substituent in R ¹ of the general formula (1) include linear or branched alkenyl groups (vinyl, allyl, 1-propenyl, 2-propenyl, 1-butenyl, 2 -Butenyl, 3-butenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 2-methacryloyloxyethyl, 2-acryloyl Oxyethyl, 2-acryloyloxypropyl group, etc.) and cycloalkenyl groups (2-cyclohexenyl, 3-cyclohexenyl, etc.), preferably 2-methacryloyloxyethyl group, 2-acryloyloxyethyl group. More preferably a 2-methacryloyloxyethyl group.

Examples of the aryl group which may have a substituent in R ¹ of the general formula (1) include monocyclic aryl groups (phenyl, benzyl, tolyl, o-xylyl, tosyl group, etc.), and preferably Is a phenyl group or a tosyl group, more preferably a phenyl group.

Examples of the heteroaryl group which may have a substituent in R ¹ of the general formula (1) include an epoxy group (such as a glycyl group), a furyl group (such as a tetrahydrofurfuryl group and a furfuryl group), a thienyl group, and a pyranyl group. And a pyridyl group, and the like, preferably a thienyl group, a furfuryl group, and a tetrahydrofurfuryl group.

R ^{1 in the} general formula (1) is preferably an alkyl group which may have a substituent and a substituted or unsubstituted aryl group, more preferably an unsubstituted alkyl group and an unsubstituted aryl group. Particularly preferred groups include unsubstituted alkyl groups.

When the group represented by R ¹ in the general formula (1) has a substituent, examples of the group that can be substituted include a substituent selected from a halogen atom, a hydroxyl group, and the like. Examples of the halogen atom include fluorine, chlorine, bromine and iodine.

R ^{1 in the} general formula (1) may include not only a single substituent but also a plurality of different substituents.

R ^{2 in the} general formula (1) represents an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group, preferably a propyl group, and l in the general formula (1) is 0 to 99.8. Yes, m is from 0.1 to 99.9, n is from 0.1 to 30.5, and o is from 0 to 77.0.

R ¹ in the general formula (1) may be a group represented by the general formula (2).
General formula (2)


[R ³ may have an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a good heteroaryl group.
R ⁴ represents a substituted or unsubstituted (α + 1) -valent linking group.
α represents an integer of 1 to 3. ]

R ^{3 in the} general formula (2) represents an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. The heteroaryl group which may have is represented.

It has an alkyl group which may have a substituent of R ^{3 in} the general formula (2), an alkenyl group which may have a substituent, an aryl group which may have a substituent, and a substituent. The heteroaryl group which may be substituted has an alkyl group which may have a substituent of R ^{1 in} the general formula (1), an alkenyl group which may have a substituent, or a substituent. An aryl group which may have the same meaning as a heteroaryl group which may have a substituent,
R ^{3 in the} general formula (2) is preferably an alkyl group which may have a substituent, or an aryl group which may have a substituent, and an alkyl group which may have a substituent. More preferred is an unsubstituted alkyl group.
As the alkyl group which may have a substituent of R ^{3 in} the general formula (2), an alkyl group having 1 to 18 carbon atoms is preferable,
As the alkenyl group which may have a substituent of R ^{3 in} the general formula (2), a 2-methacryloyloxyethyl group and a 2-acryloyloxyethyl group are preferable,
As the aryl group which may have a substituent of R ^{3 in} the general formula (2), a phenyl group and a tosyl group are preferable, and a phenyl group is more preferable,
As the heteroaryl group of R ^{3 in} the general formula (2), a glycyl group or a tetrahydrofurfuryl group is preferable, and a tetrahydrofurfuryl group is more preferable.

When the group represented by R ³ in the general formula (2) has a substituent, the group that can be substituted has the same meaning as the group that can be substituted in R ^{1 in} the general formula (1).

R ^{4 in the} general formula (2) represents a (α + 1) -valent linking group which may have a substituent, and α represents an integer of 1 to 3.
In the case of α = 1, R ⁴ is a divalent linking group which may have a substituent. Specifically, it has an alkylene group which may have a substituent, or a substituent. Phenylene group which may be sufficient, or group shown in the following (5-1)-(5-16), etc. are mentioned.

Examples of the alkylene group which may have a substituent in R ⁴ of the general formula (2) include a linear alkylene group (such as trimethylene, tetramethylene, pentamethylene, hexamethylene, dodecamethylene group), a branched alkylene group ( 2,4,4′-trimethylhexamethylene group), cyclic alkylene group (1,2-cyclopentyl group, 1,3-cyclopentyl group, 1,2-cyclohexyl group, 1,3-cyclohexyl group, 1,4- Cyclohexyl group, methyl-2,4-cyclohexyl group, and methyl-2,6-cyclohexyl group).

Examples of the phenylene group which may have a substituent in R ⁴ of the general formula (2) include 1,3-phenylene, 1,4-phenylene group, 2-methyl-1,3-phenylene group, 4-methyl Examples include -1,3-phenylene, 1,3-dimethylphenylene, 1,4-dimethylphenylene group, and 1,4-diethylphenylene group.

Specific examples of the linking group optionally having a substituent in R ⁴ of the general formula (2) include groups shown in the following (5-1) to (5-16), and are preferably used. .

R ^{8 in} (5-1) to (5-16) is an alkyl group having 1 to 3 carbon atoms, and R ⁹ in (5-8) is an alkyl group having 1 to 3 carbon atoms. is there.
Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group.

R ^{4 in} the case of α = 1 in the general formula (2) is preferably (5-1) or (5-7), and particularly preferably (5-7).

In the case of α = 2 in the general formula (2), R ⁴ represents a trivalent linking group which may have a substituent, and is shown in the following (6-1) to (6-3). Group and the like.

R ^{4 in} the case of α = 2 in the general formula (2) is preferably (6-1) or (6-2), particularly preferably (6-1).

In the case of α = 3 in the general formula (2), it represents a tetravalent linking group which may have a substituent in R ⁴ , and examples include the group shown in the following (7-1).

When the group represented by R ⁴ in the general formula (2) has a substituent, the group that can be substituted has the same meaning as the group that can be substituted in R ^{1 in} the general formula (1).

As α in R ⁴ of the general formula (2), α = 1 is preferable.

<Manufacture of resin>
The modified resin of the present invention can be obtained by a known method,
A modified polyvinyl alcohol resin (A) obtained by reacting the polyvinyl alcohol resin (a) with an isocyanate compound represented by the general formula (3) or the general formula (4), or
A modified polyvinyl acetal resin (B) obtained by reacting the polyvinyl acetal resin (b) with an isocyanate compound represented by the general formula (3) or the general formula (4) can be used and can be preferably used.
Hereinafter, the modified polyvinyl alcohol resin (A) and the modified polyvinyl acetal resin (B) will be described.

(Modified polyvinyl alcohol resin (A))
The modified polyvinyl alcohol resin (A) can be obtained by reacting the polyvinyl alcohol resin (a) with an isocyanate compound represented by the general formula (3) or the general formula (4).
[Polyvinyl alcohol resin (a)]
There is no restriction | limiting in particular about the manufacturing method of the polyvinyl alcohol resin (a) used for this invention, The various polyvinyl alcohol resin synthesize | combined by the well-known method and commercially available polyvinyl alcohol resin can be used. A typical synthesis method includes a method of producing polyvinyl alcohol by saponifying a polymer obtained by polymerizing a vinyl alcohol precursor such as vinyl acetate with an alkali.

  The polyvinyl alcohol resin (a) is represented by the following general formula (7).

General formula (7)

In general formula (7), p is 69.5-99.9 mol%, q is 0.1-30.5 mol%, and p + q = 100.0 mol%.
The average molecular weight of the polyvinyl alcohol resin (a) is preferably 1,000 to 800,000, and more preferably 8,000 to 110,000.

There is no restriction | limiting of the arrangement | sequence of two structural units shown in General formula (7), and the arrangement | sequence of a structural unit may be random.

  Examples of commercially available polyvinyl alcohol resins include Kuraray Poval PVA-102, Kuraray Poval PVA-103, Kuraray Poval PVA-110, Kura Lepoval PVA-205, Kura Lepoval PVA-405, Kura Lepoval PVA-HC, Kura Lepoval PVA- L8 (Kuraray Polyvinyl Alcohol Resin), Denkapoval K-17C, Denkapoval B-05, Denkapoval B-24 (Electrochemical Industry Polyvinyl Alcohol Resin), etc. Absent.

  In the present invention, the modified polyvinyl alcohol resin (A) mainly functions as a dispersant for the carbon-based catalyst material and is considered to play a role for creating an electrode film state suitable for improving battery performance. .

When the resin is a modified polyvinyl alcohol resin (A),
In the general formula (1), l is 0.0 to 99.8 mol%, m is 0.1 to 99.9 mol%, n is 0.1 to 30.5 mol%, and o is 0.0 mol%. However, l + m + n + o = 100.0 mol%.
l is 7.0 to 97.9 mol%, m is more preferably 1.4 to 89.9 mol%, l is 20.9 to 97.9 mol%, and m is 1.4 to 69. It is particularly preferably 9 mol%.

  The average molecular weight of the modified polyvinyl alcohol resin (A) is preferably 1,000 to 800,000, more preferably 8,000 to 800,000.

(Modified polyvinyl acetal resin (B))
The modified polyvinyl acetal resin (B) can be obtained by reacting the polyvinyl acetal resin (b) with an isocyanate compound represented by the general formula (3) or the general formula (4).

[Polyvinyl acetal resin (b)]
There is no restriction | limiting in particular about the manufacturing method of the polyvinyl acetal resin (b) used for this invention, The various polyvinyl acetal resin synthesize | combined by the well-known method and commercially available polyvinyl acetal resin can be used. A typical synthesis method is a method in which a polymer obtained by polymerizing a vinyl alcohol precursor such as vinyl acetate is saponified with an alkali to change to a vinyl alcohol structure, and this is reacted with an aldehyde to acetalize. Can be mentioned. The kind of aldehyde acted at this time can react individually or in multiple types.

  The polyvinyl acetal resin (b) is represented by the following general formula (8).

General formula (8)


In the general formula (8), s is 2.9 to 3.9 mol%, R ² is an alkyl group having 1 to 3 carbon atoms, r is 20.6 to 38.5 mol%, and t is 58. It is 7-75.5 mol%, and r + s + t = 100.0 mol%. In general formula (8), r is 29.4 to 38.5 mol%, and t is more preferably 58.7 to 66.7 mol%.

The arrangement of the three structural units shown in the general formula (8) is not limited, and the arrangement of the structural units may be random.

The average molecular weight of the polyvinyl acetal resin (b) is preferably 1,000 to 800,000, more preferably 15,000 to 130,000, and particularly preferably 25,000 to 66,000.
^{R 2} in the general formula (8) has the same meaning as ^{R 2} in the general formula (1).

  Examples of commercially available polyvinyl acetal resins include, for example, ESREC BL-1, BL-10, BM-1, BH-3 (polyvinyl butyral resin manufactured by Sekisui Chemical Co., Ltd.), ESREC BX-1, BX-L, KS-10 ( Polyvinyl acetal resin), Denkabutyral # 3000-1, # 3000-K, # 4000-2 (polyvinyl butyral resin manufactured by Denki Kagaku Kogyo), Mobital LPB16H, B20H, B30T, B30H, B30HH, B45M (manufactured by Kuraray Co., Ltd.) Polyvinyl butyral resin) and the like, but is not limited thereto.

  In the present invention, similarly to the modified polyvinyl alcohol resin (A), the modified polyvinyl acetal resin (B) mainly functions as a dispersant for the carbon-based catalyst material and has an electrode film state suitable for improving battery performance. It is thought that it also has a role to create.

(Compound represented by general formula (3) or general formula (4))
Next, the isocyanate compound represented by the general formula (3) will be described.

General formula (3)

[R ¹ may have an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a good heteroaryl group. ]

R ^{1 in the} general formula (3) represents an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents an optionally substituted heteroaryl group.

R ^{1 in} the general formula (3) may have an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. The heteroaryl group which may be substituted has an alkyl group which may have a substituent of R ^{1 in} the general formula (1), an alkenyl group which may have a substituent, or a substituent. An aryl group which may be substituted, or a heteroaryl group which may have a substituent,
When R ^{1 in the} general formula (3) has a substituent, the group that can be substituted has the same meaning as the group that can be substituted in R ^{1 in} the general formula (1).

Next, general formula (4) will be described.
General formula (4)

[R ³ may have an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a good heteroaryl group.
R ⁴ represents a substituted or unsubstituted (α + 1) -valent linking group.
α represents an integer of 1 to 3. ]

In general formula (4), an alkyl group which may have a substituent of R ^3, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent As the heteroaryl group which may have,
An alkyl group which may have a substituent of R ^{3 in} the general formula (2), an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent; It is synonymous with the heteroaryl group that it may have,
When R ^{3 in the} general formula (4) has a substituent, the group that can be substituted is the same as the group that can be substituted in R ^{1 in} the general formula (1).
The (α + 1) -valent linking group optionally having a substituent of R ^{4 in} the general formula (4) may have a (α + 1) -valent substituent having the substituent of R ^{4 in} the general formula (2). And is synonymous with the linking group of
When R ^{4 in the} general formula (4) has a substituent, the group that can be substituted is the same as the group that can be substituted in R ^{1 in} the general formula (1).
The α of ^{R 4} in the general formula (4), is synonymous with α in formula (2) in ^{R 4.}

There is no restriction | limiting in particular about the manufacturing method of the isocyanate compound shown by General formula (4) used for this invention, The isocyanate compound synthesize | combined by the well-known method can be used. As a typical synthesis method, a commercially available alcohol or commercially available phenol can be reacted with a commercially available polyfunctional isocyanate compound. The kind of alcohol which acts at this time can be made to react individually or in multiple types.
If the polyfunctional isocyanate is used as it is without being modified, it is not preferable because an excessive isocyanate group impairs the dispersion stability of the composition over time.

When the resin is a modified polyvinyl alcohol resin (B),
In the general formula (1), l is 0.0 to 99.8 mol%, m is 0.1 to 99.9 mol%, n is 2.9 to 5.0 mol%, o Is 0.0 mol%. However, l + m + n + o = 100.0 mol%.
In general formula (1), l is 0.0 to 38.3 mol%, m is 0.1 to 38.5 mol%, and o is preferably 58.7 to 75.5 mol%. Is 2.1-37.7 mol%, m is more preferably 0.4-34.6 mol%, o is more preferably 58.7-75.5 mol%, and l is 8.8-30. It is particularly preferable that it is 8 mol%, m is 5.9 to 26.9 mol%, and o is 58.7 to 66.7 mol%.

The average molecular weight of the modified polyvinyl acetal resin (B) is preferably 1,000 to 200,000, more preferably 15,000 to 200,000.

The resin in the present invention is a modified polyvinyl alcohol resin or a modified polyvinyl acetal resin, which functions as a dispersant for a carbon-based catalyst material and has excellent dispersion stability without impairing catalytic activity or conductivity. Can be provided. The catalyst paste composition of the present invention not only exhibits excellent dispersion stability, but also has excellent storage stability. When the proton conductive polymer or water repellent material is added later, the catalyst paste composition is mixed while maintaining the dispersion state. Can be dispersed. In addition, wettability with the proton conductive polymer can be improved. Therefore, since the adhesion between the carbon-based catalyst material and the proton conductive polymer in the coating film and the proton conductivity to the catalyst active site can be improved, it can be suitably used for the catalyst ink composition.

<Solvent>
As a solvent, if it is a solvent with high affinity with water or water, it will not specifically limit. In particular, alcohol can be preferably used. As such an alcohol, for example, a monohydric alcohol or a polyhydric alcohol having a boiling point of about 80 to 200 ° C. can be used, and an alcohol solvent having 4 or less carbon atoms is preferable. Specific examples include 1-propanol, 2-propanol, 1-butanol, 2-butanol, and t-butanol. Alcohol is used individually by 1 type or in mixture of 2 or more types. Among these monohydric alcohols, 2-propanol, 1-butanol and t-butanol are preferable. Specifically, the polyhydric alcohol is preferably, for example, propylene glycol, ethylene glycol or the like, particularly propylene glycol, from the viewpoint of compatibility with the hydrogen ion conductive polymer and the problem of drying efficiency when used as a catalyst ink composition. preferable.

<Catalyst ink composition for fuel cells>
The proportions of the carbon-based catalyst material, resin and proton conductive polymer or water-repellent material contained in the catalyst ink composition of the present invention are not limited and can be appropriately selected within a wide range.

  The method for preparing the catalyst ink composition is not particularly limited. In the preparation, each component may be dispersed at the same time, or after dispersing the catalyst paste composition, a proton conductive polymer component or a water repellent material may be added, and the carbon-based catalyst material, proton conductive polymer or It can be optimized by the water repellent material and the solvent type. However, if the catalyst paste composition is prepared first, and a proton conductive polymer or a water repellent material is added afterwards to prepare a catalyst ink composition, it can greatly contribute to cost reduction such as shortening of the dispersion time.

  For example, in the catalyst ink composition of the present invention, the resin is 0.01 to 25 parts by weight, preferably 0.02 to 10 parts by weight, and the proton conductive polymer is 10 to 10 parts by weight with respect to 100 parts by weight of the carbon-based catalyst material. 300 parts by weight, preferably 20 to 250 parts by weight, and the water repellent material is 5 to 100 parts by weight, preferably 10 to 90 parts by weight.

<Proton conducting polymer>
A conventionally well-known proton conductive polymer can be used. Examples of the proton conductive polymer include a fluorine-based ion exchange resin such as perfluorosulfonic acid, an olefin resin into which a strongly acidic functional group such as a sulfonic acid group is introduced, and a polyimide resin. For example, by introducing a fluorine atom having a high electronegativity, it is chemically very stable, a sulfonic acid group has a high degree of detachment, and high ionic conductivity can be realized. Specific examples of such proton conductive polymers include “Nafion” manufactured by DuPont. Usually, the proton conductive polymer is used as an alcohol aqueous solution containing about 5 to 30% by weight of the polymer. As the alcohol, for example, methanol, propanol, ethanol diethyl ether and the like are used.

<Water repellent material>
As the water repellent material, water generated by the reaction of oxygen and hydrogen ions in the catalyst layer on the cathode side, the drainage of this excess water, and any material that does not hinder gas diffusibility may be used. The surface tension of the water repellent material is preferably lower than the surface tension of water (about 72 dyn / cm). For example, fluorine resin, polypropylene, and polyethylene can be used, and among them, fluorine resin is preferable. Examples of the fluororesin include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

<Catalyst layer for fuel cell and electrode membrane assembly for fuel cell>
The catalyst layer for a fuel cell may be formed by directly applying and drying the catalyst ink composition on an electrode substrate (carbon paper or the like), and removing the catalyst ink composition from a Teflon (registered trademark) sheet or the like. It may be formed by coating and drying on a possible transfer substrate and then transferring to a solid polymer electrolyte membrane.

  When the catalyst layer for a fuel cell is produced by applying the catalyst ink composition to a transfer substrate (such as a Teflon (registered trademark) sheet) or by directly applying the catalyst ink composition to an electrode substrate and then drying, The usual coating method can be used. The coating method is not particularly limited, and for example, general methods such as knife coater, bar coater, blade coater, spray, dip coater, spin coater, roll coater, die coater, curtain coater, and screen printing can be used. Applicable.

  After coating, the coating film (fuel cell catalyst layer) is formed by drying. A drying temperature is about 40-120 degreeC normally, Preferably it is about 75-95 degreeC. The drying time is usually about 5 minutes to 2 hours, preferably about 30 minutes to 1 hour, although it depends on the drying temperature. The thickness of the fuel cell catalyst layer after coating and drying is usually about 5 μm to 80 μm, preferably about 10 μm to 70 μm.

  The pressure level in transferring the above fuel cell catalyst layer to the solid polymer electrolyte membrane is usually about 0.5 Mpa to 20 Mpa, preferably about 1 Mpa to 10 Mpa, in order to avoid transfer failure. Further, it is preferable to heat the pressure surface during this pressure operation in order to avoid transfer failure. The heating temperature is usually 200 ° C. or lower, preferably about 120 to 150 ° C., in order to avoid damage or modification of the solid polymer electrolyte membrane.

  The electrode membrane assembly for a fuel cell in the present invention is formed by adhering a fuel cell catalyst layer on one or both sides of a proton conductive solid polymer electrolyte membrane, and further, on one or both sides of the carbon paper. It means that the electrode substrate such as is closely attached.

As a method for producing an electrode membrane assembly for a fuel cell, a fuel cell catalyst layer previously formed on an electrode substrate is bonded to one or both sides of a solid polymer electrolyte membrane by thermocompression bonding. The fuel cell electrode may be prepared by forming a catalyst layer for a fuel cell previously formed on a transfer substrate on a solid polymer electrolyte membrane by transfer and then thermocompression-bonding the electrode substrate. A membrane assembly may be produced. At this time, the electrode base material on which the fuel cell catalyst layer is formed in advance can be used.

In the fuel cell electrode membrane assembly described above, when the electrode substrate, the fuel cell catalyst layer and the solid polymer electrolyte membrane are thermocompression bonded, the pressure level is usually about 0.1 Mpa to 50 Mpa, preferably 1 Mpa. About 20 Mpa is good. The heating temperature is usually 200 ° C. or lower, preferably about 120 to 150 ° C., in order to avoid damage or modification of the solid polymer electrolyte membrane.

The electrode membrane assembly of the present invention may include a microporous layer on the side of the catalyst layer that contacts the electrode substrate. This layer is handled as a part of the catalyst layer, or is also called a water repellent layer or MPL (micro porous layer), in addition to uniform gas supply to the catalyst layer and improved conductivity. It has the role of improving the drainage of water generated during power generation on the cathode side. The water-repellent layer or MPL can be formed, for example, by applying a carbon material or a carbon-based catalyst material and an ink composition containing a water-repellent material on a carbon paper substrate and firing at about 300 ° C. The catalyst paste composition can also be suitably used.

<Solid polymer electrolyte membrane>
Examples of the solid polymer electrolyte membrane include perfluorosulfonic acid-based fluorine ion exchange resins. By introducing a fluorine atom having a high electronegativity, it is chemically very stable, the degree of sulfonic acid group dissociation is high, and high ionic conductivity can be realized. Specific examples include “Nafion” manufactured by DuPont, “Flemion” manufactured by Asahi Glass Co., Ltd., “Aciplex” manufactured by Asahi Kasei Co., Ltd., “Gore Select” manufactured by Gore, and the like. The thickness of the electrolyte membrane is usually about 20 μm to 250 μm, preferably about 10 μm to 80 μm.

<Electrode substrate (gas diffusion layer; GDL)>
The electrode base material is well known, and various electrode base materials constituting an anode or a cathode can be used. The electrode substrate is also called a gas diffusion layer or GDL, and should be porous or fibrous so that gas can pass and diffuse so that oxygen in the air can be taken in on the cathode side and hydrogen can be taken in on the anode side. preferable. Furthermore, since it is necessary to take in and out electrons, a conductive material must be used. The electrode base material may be any material having conductivity, but preferably carbon paper made of carbon fiber. Specific examples include “TGP-H-090” manufactured by Toray Industries, Inc.

<Transfer substrate>
The transfer substrate is a film substrate for applying a catalyst ink composition to form a fuel cell catalyst layer and transferring the catalyst layer on the transfer substrate to a solid polymer electrolyte membrane such as Nafion. As the transfer substrate, a polymer film that is inexpensive and easily available is preferable, and polytetrafluoroethylene, polyimide, polyethylene terephthalate, and the like are more preferable. Specific examples include Teflon (registered trademark) sheets. The thickness of the transfer substrate is usually about 6 μm to 100 μm, preferably about 10 μm to 50 μm, more preferably about 15 μm to 30 μm, from the viewpoints of handleability and economy.

<Fuel cell>
Since the fuel cell of the present invention is superior in dispersibility of the fuel cell catalyst paste composition and the fuel cell catalyst ink composition as compared with the conventional fuel cell, the carbon-based catalyst material can be suitably brought into contact with a gas such as oxygen gas. Thus, the oxygen reduction potential and the oxygen reduction current density (sometimes simply referred to as current density) are improved, and the coating unevenness and pinholes are small, so that there is an advantage that the durability is excellent.

  Below, an example of the method of evaluating the performance of a fuel cell is shown. A fuel cell electrode membrane assembly is used as a sample of 5 cm square, and two gaskets are sandwiched from both sides thereof, then two separators which are graphite plates are sandwiched, and two current collector plates are further attached from both sides to produce a single cell. . Battery characteristics are measured by supplying humidified oxygen gas from the cathode (air electrode) side and supplying humidified hydrogen gas from the anode (fuel electrode) side.

  As described above, the fuel cell catalyst layer produced using the fuel cell catalyst paste composition or fuel cell catalyst ink composition of the present invention is likely to come into contact with a gas such as oxygen gas. As a result, there are advantages that the oxygen reduction potential and current density are improved, coating unevenness and pinholes are small, and durability is excellent. Therefore, the fuel cell produced using the fuel cell catalyst layer and the fuel cell electrode membrane assembly of the present invention is more economical and cost superior than the conventional fuel cell, and the catalyst is poisoned. It has the advantage that it is excellent in durability.

  Hereinafter, the present invention will be described based on examples, but the present invention is not limited thereto. In Examples and Comparative Examples, “part” means “part by weight” and “%” means “% by weight” unless otherwise specified.

<Synthesis of isocyanate compound represented by general formula (4)>
(Synthesis of Isocyanate Compound NCO (7))
In a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer, 200.0 parts of N-methyl-2-pyrrolidone, 100.0 parts of isophorone diisocyanate (1 equivalent), and 14.42 parts of methanol (1 etc.) Amount) was charged and replaced with nitrogen gas. The inside of the reaction vessel was heated to 80 ° C., and 0.01 part of U-810 (manufactured by Nitto Kasei) was added. The reaction vessel was heated to 100 ° C. and the reaction was continued for 3 hours. Then, the NCO value was measured and it was confirmed that the reaction rate was 95%. Thereafter, N-methyl-2-pyrrolidone was added to dilute the solid content to 30%. Then, it cooled and the isocyanate compound NCO (7) solution was obtained.

(Synthesis of Isocyanate Compounds NCO (8) to (11))
The compounding composition shown in Table 1 was synthesized by the same method as the synthesis of the isocyanate compound NCO (7) to obtain isocyanate compound NCO (8) to NCO (11) solutions.

<Synthesis of modified polyvinyl alcohol resin>
(Synthesis of Resin (A-1) (Synthesis Example 1))
In a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer, 200.0 parts of N-methyl-2-pyrrolidone and 50.0 parts of PVA-102 were charged and replaced with nitrogen gas. The inside of the reaction vessel was heated to 60 ° C., and 1.11 parts of butyl isocyanate was added. The inside of the reaction vessel was heated to 90 ° C., and 0.01 part of Neostan U-810 (manufactured by Nitto Kasei) was added. After the addition, the inside of the reaction vessel was heated to 110 ° C. and the reaction was continued for 2 hours. Thereafter, the NCO value was measured, and it was confirmed that the reaction rate was 95% or more. Thereafter, N-methyl-2-pyrrolidone was added for dilution. V. = 20%. Then, it cooled and obtained the resin solution (A'-1) containing a modified polyvinyl alcohol resin (A-1).

(Synthesis (synthesis of modified polyvinyl alcohol resins (A-2) to (A-12), modified polyvinyl acetal resins (B-1) to (B-13), and other resins (C-1) to (C-3)) Examples 2-28))
A polyvinyl alcohol resin (a), a polyvinyl acetal resin (b), and an isocyanate compound were synthesized in the same manner as in Synthesis Example 1 except that the types and blending amounts shown in Table 2 were changed. Resin solutions (B′-1) containing resin solutions (A′-2) to (A′-12) containing 2) to (A-12) and modified polyvinyl acetal resins (B-1) to (B-13) ) To (B′-13) and other resin solutions (C′-1) to (C′-3) containing the resins (C-1) to (C-3) were obtained. In other resins (C-1) to (C-3), a polyfunctional isocyanate compound was used as an isocyanate compound without reacting with alcohol in advance.

Abbreviations in Table 2 are shown below.
<Polyvinyl alcohol resin (a)>
PVA-102: Kuraray Poval PVA-102 (manufactured by Kuraray): degree of saponification: 98.0-99.0%, degree of polymerization: 200.
PVA-103: Kuraray Poval PVA-103 (manufactured by Kuraray): degree of saponification: 98.0-99.0%, degree of polymerization: 300.
PVA-110: Kuraray Poval PVA-110 (manufactured by Kuraray): degree of saponification: 98.0-99.0%, degree of polymerization: 1000.
PVA-205: Kuraray Poval PVA-205 (manufactured by Kuraray): degree of saponification: 86.5-89.0%, degree of polymerization: 500.
PVA-405: Kuraray Poval PVA-405 (manufactured by Kuraray): degree of saponification: 78.5-81.5%, degree of polymerization: 500.
K-17C: Denkapoval K-17C (manufactured by Denki Kagaku Kogyo): degree of saponification: 98.7-99.7%, degree of polymerization: 1700.
B-05: Denkapoval B-05 (manufactured by Denki Kagaku Kogyo): degree of saponification: 86.5% -89.5%, degree of polymerization: 500.
B-24: Denkapoval B-24 (manufactured by Denki Kagaku Kogyo): degree of saponification: 86.0% -89.0%, degree of polymerization: 2400.
PVA-HC: Kuraray Poval PVA-HC (manufactured by Kuraray): Saponification degree: 99.85% or more.
PVA-L8: Kuraray Poval PVA-L8 (manufactured by Kuraray): Degree of saponification: 69.5% -72.5%.

<Polyvinyl acetal resin (b)>
BL-1: ESREC BL-1 (manufactured by Sekisui Chemical Co., Ltd.): polyvinyl butyral resin, repeating unit containing a hydroxyl group: 25%, calculated molecular weight: 19,000.
BL-S: ESREC BL-S (manufactured by Sekisui Chemical Co., Ltd.): polyvinyl butyral resin, repeating unit containing a hydroxyl group: 15%, calculated molecular weight: 23,000.
BM-1: S-REC BM-1 (manufactured by Sekisui Chemical Co., Ltd.): polyvinyl butyral resin, repeating unit containing a hydroxyl group: 24%, calculated molecular weight: 40,000.
BM-S: ESREC BM-S (manufactured by Sekisui Chemical Co., Ltd.): polyvinyl butyral resin, repeating unit containing a hydroxyl group: 22%, calculated molecular weight: 53,000.
-BH-3: ESREC BH-3 (manufactured by Sekisui Chemical Co., Ltd.): polyvinyl butyral resin, repeating unit containing a hydroxyl group: 24%, calculated molecular weight: 110,000.
-BH-6: ESREC BH-6 (manufactured by Sekisui Chemical Co., Ltd.): polyvinyl butyral resin, repeating unit containing a hydroxyl group: 30%, calculated molecular weight: 92,000.
BH-S: ESREC BH-S (manufactured by Sekisui Chemical Co., Ltd.): polyvinyl butyral resin, repeating unit containing a hydroxyl group: 14%, calculated molecular weight: 66,000.
BX-L: ESREC BX-L (manufactured by Sekisui Chemical Co., Ltd.): polyvinyl acetal resin, repeating unit containing a hydroxyl group: 37 ± 3%, calculated molecular weight: 20,000.
BL-5: ESREC BL-5 (manufactured by Sekisui Chemical Co., Ltd.): polyvinyl butyral resin, repeating unit containing a hydroxyl group: 21%, calculated molecular weight: 32,000.

Modified resins (A-1) to (A-12) obtained in Synthesis Examples 1 to 28 or (B-1) to (B-13) represented by l, m, n, o in the general formula (1) Values are shown in Table 3.

<Production example of carbon-based catalyst material> [Production example 1: Preparation of carbon-based catalyst material X1]
Using polyvinyl pyridine (manufactured by Aldrich: Mw: 60,000) as a starting material, 10 g of polyvinyl pyridine iron (II) complex is obtained, and 10 g of this ketjen black EC300 (manufactured by Lion Corporation) is dry-mixed in a mortar for 20 minutes. Then, it was baked in an electric furnace under a nitrogen atmosphere (0.5 L / min) at 800 ° C. for 1 hour (temperature rising 1.5 hours). The fired product was dry-ground with a mortar and classified with a 150 mesh sieve. Furthermore, in order to remove the metal, stirring and decantation were repeated three times in 37% hydrochloric acid, and finally heat treatment was performed in an electric furnace under a nitrogen atmosphere (0.5 L / min) at 700 ° C. for 1 hour (temperature rising 2 hours). And then dry-pulverized and classified with 150 mesh to obtain a carbon-based catalyst material X1.

[Production Example 2: Preparation of carbon-based catalyst material X2]
13.1 g of metal-free phthalocyanine which is a nitrogen-containing compound is mixed with 10 g of furfuryl alcohol which is a precursor of furan resin, 10 g of 1M-hydrochloric acid is added, and this mixture is heated at 80 ° C. in an oven to thereby add phthalocyanine-containing furan. A resin was obtained. This was further heat-treated in a nitrogen atmosphere in an oven at a rate of 10 ° C./min from room temperature and kept at 1000 ° C. for 1 hour. As a result, a carbonized product of a phthalocyanine-containing furan resin was obtained. This carbonized product was pulverized with a planetary ball mill (manufactured by Lecce, PM100) to obtain a carbon-based catalyst material X2 having an average particle diameter of 0.1 μm doped with 13.4 mol% of nitrogen atoms.

[Production Example 3: Preparation of carbon-based catalyst material X3]
Iron phthalocyanine (manufactured by Sanyo Pigment) and Ketjen black (EC-300J by Lion) were weighed at a weight ratio of 1: 1 and dry-mixed in a mortar to obtain a precursor.
The precursor powder was filled into an alumina crucible and heat-treated at 700 ° C. for 2 hours in a nitrogen atmosphere in an electric furnace to obtain a carbon-based catalyst material X3.

[Production Example 4: Preparation of carbon-based catalyst material X4]
Cobalt phthalocyanine (manufactured by Tokyo Chemical Industry Co., Ltd.) and Ketjen black (EC-600JD manufactured by Lion Corporation) were weighed at a weight ratio of 0.5: 1 and dry-mixed in a mortar to obtain a precursor.
The precursor powder was filled into an alumina crucible and heat-treated at 800 ° C. for 2 hours in a nitrogen atmosphere in an electric furnace to obtain a carbon-based catalyst material X4.

<Preparation of catalyst paste composition>
[Example 1-a]
9 parts by weight of the carbon-based catalyst material X1, 58.75 parts by weight of propanol (manufactured by Kishida Chemical Co., Ltd.) as a solvent, 2.25 parts by weight of the resin solution (A′-1) shown in Table 2 (100% of the carbon-based catalyst material) The catalyst paste composition 1 of the present invention (solid content concentration of 12. 9% by weight) was prepared.

[Example 2-a to Example 36-a]
A catalyst paste composition was prepared in the same manner as in Example 1-a except that the types and compositions of the carbon-based catalyst material, the solvent, and the resin solution were changed to Table 4.

[Comparative Examples 1-a to 9-a]
A catalyst paste composition was prepared in the same manner as in Example 1-a except that the type and composition of the carbon-based catalyst material and solvent were changed as shown in Table 4.

<Evaluation of catalyst paste composition>
The dispersibility of the catalyst paste composition was evaluated based on the viscosity and the dispersed particle size.
The viscosity was measured using an E type viscometer (“RE80 type viscometer” manufactured by Toki Sangyo Co., Ltd.) at a rotation speed of 50 rpm and a temperature of 25 ° C.
For the particle size, the volume particle size distribution was measured using a dynamic light scattering particle size distribution meter ("MICROTRACK UPA" manufactured by Nikkiso Co., Ltd.), and the volume ratio of the particles from the fine particle size was integrated. The average particle size (D ₅₀ ) was sometimes 50%.
Table 4 shows the results of evaluation of dispersibility of the catalyst paste composition. The lower the viscosity and the smaller the particle size, the better the dispersibility.

[Example 1-b Preparation of catalyst ink composition]
To the catalyst paste composition obtained in Example 1-a, 30 parts by weight of a 20 wt% Nafion (R) dispersion solution (manufactured by DuPont, CTypeDE2020) is added as a proton conductive polymer, and Disper (Primix) is added. , TK homodispers) The total ratio of the carbon-based catalyst material and the proton conductive polymer when the catalyst ink composition (solid content concentration 15% by weight, catalyst ink composition 100% by weight) was mixed by stirring. ) Was prepared.

[Example 2-b to Example 36-b, Comparative Example 1-b to Comparative Example 9-b]
The catalyst paste composition obtained in Example 1-a was changed to the catalyst paste composition obtained in Example 2-a to Example 36-a and Comparative Example 1-a to Comparative Example 9-a, respectively. Were prepared in the same manner as in Example 1-b, respectively.

<Evaluation of catalyst ink composition>
The catalyst ink composition was evaluated by the following storage stability evaluation and dispersibility evaluation.

(Storage stability evaluation)
The storage stability of the catalyst ink composition is determined by measuring the viscosity immediately after preparation (initial viscosity) and the viscosity after storage at 50 ° C. for 10 days (time-dependent viscosity), and the rate of change in viscosity (time-dependent viscosity / initial viscosity). Evaluated by. All the viscosities were measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., “RE80 viscometer”) at a rotation speed of 50 rpm and a temperature of 25 ° C.

  Table 5 shows the results of the storage stability evaluation of the catalyst ink composition. The smaller the viscosity change rate, the better the storage stability. In addition, in the catalyst ink composition of the present invention, no occurrence of precipitates was observed, no increase in viscosity was observed even after storage at 20 ° C. for 3 months, and the coating property after storage was good, It was confirmed that a uniform coating film was obtained.

(Dispersibility evaluation)
The dispersibility was determined by a grind gauge (according to JIS K5600-2-5), and the particle size of the catalyst ink composition was determined. When there was no aggregate of 30 μm or more, the dispersibility was evaluated as good. The catalyst ink compositions of the present invention were all 10 to 20 μm and the dispersibility was good, whereas the catalyst ink compositions obtained in Comparative Examples 1-b to 9-b were all 30 μm or more. The aggregate was confirmed, and it was confirmed that the dispersibility was inferior.

<Creation of fuel cell catalyst layer>
[Example 1-c Production of fuel cell catalyst layer I]
The catalyst ink composition obtained in Example 1-b was applied onto a Teflon (registered trademark) film by a doctor blade so that the basis weight of the carbon-based catalyst material after drying was 2 mg / cm ² , and the atmosphere Then, by drying at 95 ° C. for 60 minutes, the catalyst layer I for cathode fuel cell of the present invention was produced.

[Example 2-c to Example 36-c, Comparative Example 1-c to Comparative Example 9-c]
Except for changing the catalyst ink composition obtained in Example 1-b to the catalyst ink composition obtained in Example 2-b to Example 36-b and Comparative Example 1-b to Comparative Example 9-b, respectively. In the same manner as in Example 1-c, a cathode fuel cell catalyst layer I was prepared.

(Coating property evaluation)
The fuel cell catalyst layer I was subjected to the following coating property evaluation. The fuel cell catalyst layer I formed on the Teflon (registered trademark) film was observed with a video microscope VHX-900 (manufactured by Keyence Corporation) at a magnification of 500 times, and coating unevenness (unevenness: evaluated by the density of the catalyst layer) ) And pinholes (evaluated by the presence or absence of defects on which the catalyst layer is not applied) were determined according to the following criteria. The results are shown in Table 6.
(village)
○: The density of the catalyst layer is not confirmed (good).
(Triangle | delta): Although there are 2-3 shades of a catalyst layer, it is a very small area | region (it is satisfactory practically).
X: A large number of shades of the catalyst layer is confirmed, or one or more of the stripes having a length of 5 mm or more (defective).
(Pinhole)
○: No pinholes are confirmed (good).
Δ: There are 2 to 3 pinholes but they are very small (defect).
X: Many pinholes are confirmed, or one or more pinholes having a diameter of 1 mm or more (very poor).

[Preparation of anode fuel cell catalyst layer]
Here, a method for producing a catalyst layer for an anode fuel cell used for producing an electrode membrane assembly for a fuel cell will be described below.
Instead of the carbon-based catalyst material, 4 parts by weight of platinum catalyst-supporting carbon (manufactured by Tanaka Kikinzoku Co., Ltd., 46% platinum, TEC10E50E), 56 parts by weight of propanol (manufactured by Kishida Chemical Co.) as a solvent, and 20 parts by weight of water are disperse ( A catalyst paste composition (solid content concentration: 4% by weight) was prepared by stirring and mixing with Primix Co., Ltd. (TK homodisper). Next, 20 parts by weight of 20% by weight Nafion (R) dispersion solution (manufactured by DuPont, CStype DE2020) is added as a proton conductive polymer, and the mixture is stirred and mixed with a disper (Primix, TK homodisper). A catalyst ink composition was prepared (total ratio of carbon-based catalyst material and proton conductive polymer when the solid content concentration was 8% by weight and the catalyst ink composition was 100% by weight). The obtained catalyst ink composition is applied on a Teflon (registered trademark) film so that the weight per unit area of the platinum catalyst-supporting carbon is 0.46 mg / cm ^2, and is dried for 60 minutes in an air atmosphere at 80 ° C. Thus, a catalyst layer for an anode fuel cell was produced.

[Example 1-d Production of electrode membrane assembly α for fuel cell]
The cathode fuel cell catalyst layer I prepared in Example 1-c and the anode fuel cell catalyst layer were adhered to both surfaces of a solid polymer electrolyte membrane (Nafion 212, manufactured by DuPont, film thickness 51 μm). Then, after sandwiching at 150 ° C. and 5 Mpa, the Teflon (registered trademark) film was peeled off. Next, the electrode base material (gas diffusion layer GDL, carbon paper made of carbon fiber, TGP-H-090, manufactured by Toray Industries, Inc.) is further adhered from both sides, and the electrode membrane assembly α (GDL for fuel cell) of the present invention is adhered. / Catalyst layer / solid polymer electrolyte membrane / catalyst layer / GDL).

[Example 2-d to Example 36-d, Comparative Example 1-d to Comparative Example 9-d]
Instead of the fuel cell catalyst layer I prepared in Example 1-c, the fuel cell catalyst layer I prepared in Example 2-c to Example 36-c and Comparative Example 1-c Comparative Example 9-c were used. A fuel cell electrode membrane assembly α was produced in the same manner as in Example 1-d except that the change was made.

  The fuel cell electrode membrane assembly α (GDL / catalyst layer / solid polymer electrolyte membrane / catalyst layer / GDL) of the present invention prepared in Example 1-d to Example 36-d was used as a catalyst layer after transfer. A uniform electrode film was formed without cracks or chips. On the other hand, all of the fuel cell electrode membrane assemblies α produced in Comparative Examples 1-d to 9-d were in a poor state such as cracking or chipping during transfer.

[Example 1-e Production of fuel cell (single cell)]
The fuel cell electrode membrane assembly α obtained in Example 1-d was used as a sample of 5 cm square, and sandwiched between two gaskets from both sides and then two separators, which were graphite plates, and two current collector plates from both sides. A sheet was mounted to produce a fuel cell (single cell). The measurement was carried out with an Auto PEM series “PEFC evaluation system” (manufactured by Toyo Technica). The cell characteristics were measured by supplying humidified oxygen gas from the cathode (air electrode) side and supplying humidified hydrogen gas from the anode (fuel electrode) side.

[Example 2-e to Example 36-e, Comparative Example 1-e to Comparative Example 9-e]
Instead of the fuel cell electrode membrane assembly α of Example 1-d used in Example 1-e, Example 2-d to Example 36-d and Comparative Example 1-d to Comparative Example 9-d, respectively. A single cell of a fuel cell was produced in the same manner as in Example 1-e except that the electrode membrane assembly α for a fuel cell obtained in the above was changed.

(Evaluation of fuel cell (single cell))
The battery performance was evaluated by measuring the current-voltage characteristics of the single cells prepared in Example 1-e to Example 36-e and Comparative Example 1-e to Comparative Example 9-e. The results are shown below. In the single cell produced in Example 1-e, the open circuit voltage was 0.85 V and the short-circuit current density was 1200 mA / cm ² , and even in the single cells produced in Examples 2-e to 36-e, the open circuit voltage was 0. They were 8V-0.85V and short circuit current density 800-1400mA / cm < ² >. In contrast, the single cell produced in Comparative Example 1-E to Comparative Example 9-e, open voltage 0.7V～0.77V, was short-circuit current density ^{400mA / cm 2 ~600mA / cm 2} .

<Method of producing catalyst layer for fuel cell by directly applying to gas diffusion layer>
Hereinafter, a method for preparing a fuel cell catalyst layer by directly applying the catalyst ink composition of the present invention to a gas diffusion layer will be described.

[Example 1-IIa Preparation of catalyst paste composition]
In Example 1-a, except that propanol was changed to 45 parts by weight, a catalyst paste composition having a solid content concentration of 12% by weight was obtained in the same manner as Example 1-a.

[Example 2-IIa to Example 36-IIa]
In Example 2-a to Example 36-a, except that propanol or water was changed to 45 parts by weight, in the same manner as in Example 2-a to Example 36-a, the solid content concentration was 12% by weight, respectively. The catalyst paste composition was obtained.

[Comparative Example 1-IIa to Comparative Example 9-IIa]
In Comparative Example 1-a to Comparative Example 9-a, except that propanol was changed to 45 parts by weight, a catalyst paste composition having a solid content concentration of 20% by weight was obtained in the same manner as in Example 1-IIa. However, precipitation occurred and a catalyst paste composition could not be obtained. As a result of trying to increase the solid content concentration, the carbon-based catalyst material seems to have agglomerated and sedimented.

[Example 1-IIb Preparation of catalyst ink composition]
In addition to the catalyst paste composition prepared in Example 1-IIa, 12 parts by weight of a 20 wt% Nafion (Nafion®) dispersion solution (manufactured by DuPont, CTypeDE2020) as a proton conductive polymer was added, and Disper (Primix) was added. , TK homodispers) The total ratio of the carbon-based catalyst material and the proton conductive polymer when the catalyst ink composition (solid content concentration 20% by weight, catalyst ink composition 100% by weight) was mixed by stirring. ) Was prepared. The viscosity was 96 mPa · s. The viscosity after 10 days was 110 mPa · s.

[Example 2-IIb to Example 36-IIb]
Except for changing the catalyst paste composition obtained in Example 1-IIa to the catalyst paste composition obtained in Example 2-IIa to Example 36-IIa, respectively, in the same manner as in Example 1-IIb, A catalyst ink composition was prepared for each. All the viscosities were 80 to 120 mPa · s. The viscosity after 10 days did not change greatly, and the rate of change in viscosity was 130% or less, and the heat retention stability was good.

[Example 1-IIc Preparation of catalyst layer II for fuel cell]
Using the doctor ink obtained in Example 1-IIb, the electrode substrate (made of the gas diffusion layer GDL and carbon fibers) was adjusted with a doctor blade so that the basis weight of the carbon-based catalyst material after drying was 2 mg / cm ^2. Carbon paper, TGP-H-090, manufactured by Toray Industries, Inc.) and dried in an air atmosphere at 95 ° C. for 60 minutes to prepare a catalyst layer II for a cathode fuel cell of the present invention. A good fuel cell catalyst layer II could be formed with no coating unevenness and no dripping from the carbon paper.

[Example 2-IIc to Example 36-IIc]
The catalyst ink composition obtained in Example 1-IIb was changed to the catalyst ink composition obtained in Example 2-IIb to Example 36-IIb, respectively. Then, a catalyst layer II for a cathode fuel cell was prepared.

[Example 1-IId Fabrication of fuel cell electrode membrane assembly β]
Example 1-IIc Using the prepared cathode fuel cell catalyst layer II (catalyst ink composition fixed to carbon paper) and anode fuel cell catalyst layer, a solid polymer electrolyte membrane (Nafion 212, manufactured by DuPont) After being held at 150 ° C. and 5 Mpa so as to come into contact with the film thickness of 51 μm, the Teflon (registered trademark) film on the anode side is peeled off, and the anode side is an electrode substrate (gas diffusion layer GDL, carbon fiber) Carbon paper comprising TGP-H-090, manufactured by Toray Industries, Inc., and electrode membrane assembly β for fuel cell of the present invention (GDL / catalyst layer / solid polymer electrolyte membrane / catalyst layer / GDL) Was made.

[Example 2-IId to Example 36-IId]
Instead of the fuel cell catalyst layer II in Example 1-IIc, the fuel cell catalyst layer II obtained in Example 2-IIc to Example 36-IIc was used. Thus, an electrode membrane assembly β for a fuel cell was produced.

[Example 1-IIe Production of fuel cell (single cell)]
It produced similarly to Example 1-e, and measured the battery characteristic by the same method.

[Example 2-IIe to Example 36-IIe]
Instead of the fuel cell electrode membrane assembly β of Example 1-IId used in Example 1-IIe, the fuel cell electrode membrane assembly β obtained in Example 2-IId to Example 36-IId was used. A fuel cell was fabricated in the same manner as in Example 1-IIe, except that the changes were made.

<Fuel cell single cell evaluation>
The battery performance was evaluated by measuring the current-voltage characteristics of the single cells produced in Example 1-IIe to Example 36-IIe. The results are shown below. In the single cell manufactured in Example 1-IIe, the open-circuit voltage is 0.87 V and the short-circuit current density is 1300 mA / cm ^{2. Even} in the single cells manufactured in Example 2-IIe to Example 36-IIe, the open-circuit voltage is It was 0.8 V to 0.88 V, and the short circuit current density was 900 to 1500 mA / cm ² .

[Example 1-IIIb Preparation of catalyst ink composition containing water repellent material]
To the catalyst paste composition obtained in Example 1-1, a 20 wt% PTFE dispersion (PTFE 30-J; manufactured by Mitsui DuPont Fluoro Chemical Co., Ltd., 60% polytetrafluoroethylene aqueous dispersion was diluted with ion-exchanged water. 20 parts by weight, and a catalyst ink composition containing a water-repellent material (solid content concentration: 12% by weight, catalyst ink composition) The total proportion of the carbon-based catalyst material and the water-repellent material was 100% by weight. The viscosity was 28 mPa · s. The viscosity after 10 days was 29 mPa · s.

[Example 2-IIIb to Example 36-IIIb]
A catalyst containing a water repellent material having a solid content of 12% by weight, respectively, in the same manner as in Example 2-b to Example 36-b, except that the 20% by weight Nafion dispersion was changed to a 20% by weight PTFE dispersion. An ink composition was prepared. All the viscosities were 20 to 35 mPa · s. Further, the viscosity after 10 days did not change significantly, and the viscosity change rate was 130% or less, and the storage stability was good.

[Comparative Example 1-IIIb to Comparative Example 9-IIIb]
A catalyst ink composition containing a water-repellent material in the same manner as in Example 1-IIIb, except that in Comparative Example 1-a to Comparative Example 9-a, the 20 wt% Nafion dispersion solution was changed to a 20 wt% PTFE dispersion solution. A product was prepared. The viscosities were all 30 to 60 mPa · s, which was slightly higher than those of Examples 1-IIIb to 9-IIIb. Further, a large change was observed in the viscosity after 10 days, the rate of change in viscosity was 180% or more, and some sedimentation was also observed.

[Example 1-IIIc Preparation of water-repellent layer for fuel cell]
The catalyst substrate containing the water-repellent material prepared in Example 1-IIIb was subjected to an electrode substrate (gas diffusion layer GDL) by a doctor blade so that the basis weight of the carbon-based catalyst material after drying was 1 mg / cm ^2. , Carbon paper made of carbon fiber, TGP-H-090, manufactured by Toray Industries, Inc.), and fired in an air atmosphere at 300 ° C. for 60 minutes to form the water repellent layer for a cathode fuel cell of the present invention. Produced. An excellent water repellent layer for a cathode fuel cell could be formed without uneven coating.

[Example 2-IIIc to Example 36-IIIc]
Example 1 except that the catalyst ink composition containing the water-repellent material prepared in Example 1-IIIb was changed to the water-repellent catalyst ink composition obtained in Example 2-IIIb to Example 36-IIIb, respectively. In the same manner as IIIc, a water repellent layer for a cathode fuel cell was prepared.

[Comparative Example 1-IIIc to Comparative Example 9-IIIc]
Except that the catalyst ink composition containing the water-repellent material prepared in Example 1-IIIb was changed to the catalyst ink composition containing the water-repellent material prepared in Comparative Example 1-IIIb to Comparative Example 9-IIIb, respectively. A water-repellent layer for a cathode fuel cell was prepared in the same manner as in Example 1-IIIc. The resulting water repellent layer for a fuel cell for a cathode exhibited many coating unevenness and cracks.

[Example 1-IIId Fabrication of fuel cell electrode membrane assembly γ]
The cathode fuel cell catalyst layer I prepared in Example 1-3 and the anode fuel cell catalyst layer were adhered to both surfaces of a solid polymer electrolyte membrane (Nafion 212, manufactured by DuPont, film thickness 51 μm). Then, after sandwiching at 150 ° C. and 5 Mpa, the Teflon (registered trademark) film was peeled off. Next, an electrode base material (gas diffusion layer GDL, carbon paper made of carbon fiber, TGP-H-090, manufactured by Toray Industries, Inc.) is closely attached to the anode side, and manufactured in Example 1-IIIc on the cathode side. The fuel cell electrode membrane assembly γ (GDL / catalyst layer / solid polymer electrolyte membrane / catalyst layer / water repellent layer / GDL) of the present invention was prepared by closely adhering the water repellent layer for the cathode fuel cell. .

[Example 2-IIId to Example 36-IIId]
Instead of the fuel cell catalyst layer I prepared in Example 1-3, the fuel cell catalyst layer I prepared in Example 2-3 to Example 36-3 was changed, respectively, and on the cathode side, Except that the water-repellent layer for cathode fuel cells prepared in Example 2-IIIc to Example 36-IIIc was adhered in place of the water-repellent layer for cathode fuel cells prepared in Example 1-IIIc, respectively. A fuel cell electrode membrane assembly γ was produced in the same manner as in Example 1-IIId.

[Comparative Example 1-IIId to Comparative Example 9-IIId]
Instead of the fuel cell catalyst layer I produced in Example 1-3, the fuel cell catalyst layer I produced in Comparative Example 1-IIIc to Comparative Example 9-IIIc was changed, respectively. Example 1 except that the water-repellent layer for fuel cell produced in Comparative Example 1-IIIc to Comparative Example 9-IIIc was adhered in place of the water-repellent layer for fuel cell for cathode produced in Example 1-IIIc, respectively. In the same manner as in 1-IIId, a fuel cell electrode membrane assembly γ was produced.

  The electrode membrane assembly γ (GDL / catalyst layer / solid polymer electrolyte membrane / catalyst layer / water-repellent layer / GDL) for fuel cell of the present invention produced in Example 1-IIId to Example 36-IIId is a fuel cell. The water repellent layer was not cracked or chipped. On the other hand, the electrode membrane assemblies for fuel cells γ produced in Comparative Examples 1-IIId to 9-IIId all had poor conditions such as cracking and chipping.

[Example 1-IIIe Production of fuel cell (single cell)]
It produced similarly to Example 1-e, and measured the battery characteristic by the same method.

[Example 2-IIIe to Example 36-IIIe, Comparative Example 1-IIIe to Comparative Example 9-IIIe]
Example 2-IIId to Example 36-IIId and Comparative Example 1-IIId to Comparative Example 9-IIId instead of the electrode membrane assembly for fuel cell γ of Example 1-IIId used in Example 1-IIIe, respectively A single cell of a fuel cell was produced in the same manner as in Example 1-IIIe, except that the electrode membrane assembly for fuel cell γ produced in step 1 was changed.

<Evaluation of single fuel cell>
The battery performance was evaluated by measuring the current-voltage characteristics of the single cells prepared in Example 1-IIIe to Example 36-IIIe and Comparative Example 1-IIIe to Comparative Example 9-IIIe. The results are shown below. In the single cell manufactured in Example 1-IIIe, the open circuit voltage is 0.88 V and the short-circuit current is 1400 mA / cm ^{2. Even} in the single cells manufactured in Example 2-IIIe to Example 36-IIIe, the open circuit voltage is 0. It was .81 V to 0.89 V, and the short circuit current was 800 to 1600 mA / cm ² . In contrast, the unit cell produced in Comparative Example 1-IIIe~ Comparative Example 9-IIIe, open voltage 0.7～0.77V, both the short-circuit current 300mA ^/ cm ² ~600mA ^/ cm 2 was low-performance It was.

Claims (8)

A fuel cell catalyst paste composition comprising a resin represented by the general formula (1) and a non-platinum-based carbon-based catalyst material.
General formula (1)


[R ¹ may have an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. A good heteroaryl group, or a group represented by the general formula (2), wherein R ² is an alkyl group having 1 to 3 carbon atoms;
l = 0.0-99.8 mol%
m = 0.1-99.9 mol%
n = 0.1-30.5 mol%
o = 0.0-75.5 mol%
l + m + n + o = 100 mol%. ]

General formula (2)

[R ³ has an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a good heteroaryl group.
R ⁴ represents an (α + 1) -valent linking group which may have a substituent,
α represents an integer of 1 to 3. ] 2. The resin according to claim 1, wherein the resin is obtained by reacting a polyvinyl alcohol resin (a) or a polyvinyl acetal resin (b) with a compound represented by the general formula (3) or the general formula (4). Catalyst paste composition for fuel cells.
General formula (3)

[R ¹ may have an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a good heteroaryl group. ]
General formula (4)

[R ³ may have an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a good heteroaryl group.
R ⁴ represents a (α + 1) -valent linking group which may have a substituent.
α represents an integer of 1 to 3. ] The fuel cell catalyst according to claim 1 or 2, wherein the resin is obtained by reacting a polyvinyl alcohol resin (a) or a polyvinyl acetal resin (b) with a compound represented by the general formula (3). Paste composition.
General formula (3)

[R ¹ may have an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a good heteroaryl group. ] The catalyst paste composition for a fuel cell according to any one of claims 1 to 3, wherein the resin is obtained by reacting the polyvinyl acetal resin (b) with a compound represented by the general formula (3).
General formula (3)

[R ¹ may have an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. Represents a good heteroaryl group. ]   A fuel cell catalyst ink composition comprising the fuel cell catalyst paste composition according to claim 1 and at least one of a proton conductive polymer and a water repellent material.   A fuel cell catalyst layer or a fuel cell water repellent layer formed from the fuel ink catalyst ink composition according to claim 5.   A fuel cell electrode membrane assembly comprising a solid polymer electrolyte membrane, at least one of a fuel cell catalyst layer or a fuel cell water repellent layer according to claim 6, and a gas diffusion layer.   A fuel cell comprising the electrode membrane assembly for a fuel cell according to claim 7.