JP2003327694A - Polybenzazole compound having sulfonic acid group and/ or phosphonic acid group, resin composition containing the same, resin molded article, solid polymeric electrolyte film, solid electrolyte film/electrode catalyst layer composite, and manufacturing method for the composite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a novel polymer material capable of becoming a solid polymeric electrolyte excellent not only in processability, solvent resistance and durable stability but also in ion conductivity by introducing a sulfonic acid group or a phosphonic acid group into a polybenzazole compound having excellent properties from an aspect of heat resistance, solvent resistance, mechanical characteristics, or the like. <P>SOLUTION: A specific polybenzazole compound containing an aromatic dicarboxylic acid bond unit having a sulfonic acid group and/or a phosphonic acid group, a resin composition, a resin molded article, a solid polymeric electrolyte film, a composite of solid polymeric electrolyte film/electrode catalyst layer and a manufacturing method for the composite of solid polymeric electrolyte film/electrode catalyst layer are disclosed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group useful as a solid polymer electrolyte membrane, a resin composition containing the same, a resin molded product, and a solid polymer. The present invention relates to an electrolyte membrane, a solid polymer electrolyte membrane / electrode catalyst layer composite, and a method for producing the composite.

[0002]

2. Description of the Related Art At present, fuel cells are drawing attention as a candidate for a global environment-friendly power generation system that replaces thermal power generation. A fuel cell is not a so-called dry battery or a storage battery that stores and uses electricity. When water is hydrolyzed by electricity, hydrogen and oxygen are generated. The fuel cell uses the reverse principle. That is, the fuel cell refers to a new power generation system that directly converts chemical energy into electric energy by an electrochemical reaction between hydrogen and oxygen via a catalyst or the like.

Here, a fuel cell is a power generation system that directly converts chemical energy into electric energy,
Since it is not limited by the Carnot cycle and does not generate heat transfer loss or mechanical loss, it theoretically has significantly higher power generation efficiency than thermal power generation. However, even in a fuel cell, not all the thermal energy obtained in combustion, that is, the amount of change in enthalpy (represented by ΔH) can be converted into electrical energy, and the amount of change in Gibbs free energy (represented by ΔG) is converted into electrical energy. It can only be converted.

In fact, the theoretically possible maximum efficiency (theoretical efficiency) of a fuel cell using hydrogen as a fuel is H ₂ (gas) + 1 / 2O ₂ (gas) → H ₂ O (liq
uid) ΔH = −285.83 kJ / mol Since ΔG = −237.13 kJ / mol, ΔG / ΔH × 100 = 82.9%.

As described above, the theoretical efficiency of the fuel cell is a value far exceeding the theoretical efficiency of the heat engine shown in the Carnot cycle. Similarly, when methane or alcohol is used as the fuel, the theoretical efficiency becomes a value exceeding 90%.

However, it is difficult at present to realize an efficiency close to the theoretical efficiency in an actual fuel cell. The reason is,
This is because various energy losses occur inside the fuel cell and in the auxiliary device of the fuel cell and are released to the outside as heat energy.

At present, the largest loss in a power generation system using a fuel cell is the loss inside the fuel cell. By reducing this, the power generation efficiency of the fuel cell can be greatly improved.

For the above reasons, active research and development is being carried out in various fields in order to bring the efficiency of the fuel cell close to the theoretical efficiency, such as phosphoric acid type, solid polymer type, molten carbonate type, solid electrolyte type, etc. Various types of fuel cells have been developed.

Among these fuel cells, the polymer electrolyte fuel cell (also referred to as PEFC) operates at a lower temperature than other types of fuel cells, and therefore has less restrictions on materials to be used and plastics. Inexpensive materials such as carbon, carbon, and stainless steel can be used, and it is easy to reduce the cost. In addition, PEFC
Since it can be downsized as compared to other types of fuel cells, it is suitable for mobile power sources or small capacity power sources.

The history of PEFC development is 195.
It was first developed by General Electric Company of the United States in the latter half of the 1980s, and started in the first half of the 1960s when a fuel cell using hydrogen / oxygen with an output of 1 kW was installed in a Gemini spacecraft. The polymer electrolyte membrane used initially was a polystyrene-based membrane, which had poor chemical durability, but a fluororesin-based polymer electrolyte developed by DuPont in the USA for the fuel cell for NASA space program. With the advent of the membrane "Nafion (R)", the chemical durability of PEFC has dramatically improved, and PEFC has been actively developed. At present, PEFCs are mainly considered for use in automobiles or households, rather than in conventional space and military applications.

The polymer electrolyte membrane, which is the heart of PEFC, functions as a kind of ion exchange membrane and has excellent ionic conductivity, physical strength, gas barrier properties, chemical stability, electrochemical stability, and thermal stability. , Is required. Therefore, as a polymer electrolyte membrane that can be used for a long period of time, a perfluorocarbon sulfonic acid membrane typified by "Nafion (R)" manufactured by DuPont, USA has been used. Generally, a perfluorocarbon sulfonic acid film has a structure having a fluorine-based main chain and a side chain sulfonic acid group capable of adding a proton.

However, in a general perfluorocarbon sulfonic acid membrane, when it is operated at a temperature higher than 100 ° C., the water content of the membrane drops sharply and the softening of the membrane becomes remarkable. Therefore, in a fuel cell that uses methanol as a fuel,
The performance of the membrane is deteriorated due to the permeation of methanol, and sufficient performance cannot be exhibited. Further, even in a fuel cell operating at around 80 ° C. using hydrogen as a fuel, the production cost of the perfluorocarbon sulfonic acid membrane is high, which is an obstacle to the practical application of the fuel cell. Further, there is also a problem that the perfluorocarbon sulfonic acid membrane is limited in designing the fuel cell, because only those having limited parameters such as membrane thickness and ion exchange capacity are available.

In order to overcome such drawbacks, various studies have been made on polymer electrolyte membranes in which a sulfonic acid group is introduced into an aromatic ring-containing polymer. For example, sulfonated polyaryl ether sulfone (Journal of Membran
e Science, 83 , 211 (1993)), sulfonated polyetheretherketone (JP-A-6-93114), sulfonated polystyrene and the like. However, a sulfonic acid group introduced on the aromatic ring from a polymer as a raw material is likely to undergo a desulfonic acid reaction due to an acid or heat, and it cannot be said that the durability is sufficient for use as an electrolyte membrane for a fuel cell. .

As a polymer having high heat resistance and high durability, aromatic polyazole-based polymers such as polyimidazole are known, and it is possible to introduce a sulfonic acid group into these polymers and use them for the above purpose. Conceivable. As a compound having such a polymer structure, polybenzimidazole having sulfonic acid is
A compound synthesized from 3'-diaminobenzidine and 3,5-dicarboxybenzenesulfonic acid or 2,5-dicarboxybenzenesulfonic acid (Uno et al. J. Polym. S
ci., Polym. Chem., 15 , 1309 (1977)), 1, 2,
A compound synthesized mainly from 4,5-benzenetetramine and 2,5-dicarboxybenzenesulfonic acid (US
P-5, 312, 895) has been reported.

However, in these reports, attention is paid to the solubility and heat resistance of polybenzimidazole having a sulfonic acid, but the electrochemical characteristics of the sulfonic acid group in solid polymer electrolyte membrane applications are considered. It was never looked after. In particular, these compounds are inferior in terms of satisfying both heat resistance, solvent resistance, mechanical properties and ionic conduction properties, and are unsuitable for use in solid polymer electrolyte membranes and the like.

On the other hand, those mainly containing polybenzoxazole or polybenzthiazole having a sulfonic acid group also include 2,5-diamino-1,4-benzenedithiol and 3,5-dicarboxybenzenesulfonic acid or 4,5-diamino-1,4-benzenedithiol. A compound synthesized from 6-dicarboxy-1,3-benzenedisulfonic acid (J. Polym. Sci., Polym. Chem.,
34 , 481 (1996)), a compound synthesized from 4,6-diamino-1,3-benzenediol and 3,5-dicarboxybenzenesulfonic acid (JP-A-10-158213), 4,6 -A compound obtained by sulfonation of a compound synthesized from diamino-1,3-benzenediol and terephthalic acid (JP-A-4-353533), or 2,
Compounds synthesized from 5-dicarboxysulfonic acid and various diamine diols and diamine dithiols (USP-5
No. 492,996) and the like have been reported.

However, none of these have paid attention to the sulfonic acid group as a functional group for conducting proton ions, and none of them shows sufficient durability under the condition of being used as a fuel cell. For example, the technique disclosed in US Pat. No. 5,492,996 is characterized in that the sulfonic acid group is treated with an alkylammonium salt in order to bring out the alcohol solubility of the polymer. It is clear that it is not suitable for use as a material for a fuel cell, since its solubility in alcohol is a fatal drawback in applications to fuel cells and the like.

Further, few aromatic polymers having phosphonic acid groups, which are considered to have better heat resistance than sulfonic acid groups, have been noticed from the viewpoint of application as a solid polymer electrolyte. As a slight example, 4,4 '-(2,2,2-trifluoro-1-
In polybenzoxazole composed of (trifluoromethyl) ethylidene) bis (2-aminophenol), a polymer in which 5 to 50% of the dicarboxylic acid component is 3,5-dicarboxyphenylphosphonic acid has been reported (USP 5, 498,784), focusing on good solubility and possibility as a composite material, it was not considered as a solid polymer electrolyte for fuel cell applications. In fact, it is clear that this polymer is characterized by its alcohol solubility, making it unsuitable for use as a solid polymer electrolyte for fuel cells fueled with methanol. Further, since it also shows a low ionic conductivity, it can be said that it is not suitable for a solid polymer electrolyte for a fuel cell.

In addition, phosphorus-containing polyamide copolymers such as 3,5-dicarboxyphenylphosphonic acid have been reported (JP-A No. 11-286545), but this polymer also has excellent heat resistance. Only the focused property has been investigated. In addition, this polymer undergoes hydrolysis under acidic conditions used for fuel cells and cannot be used as an electrolyte membrane.

Further, the ionic group-containing polyazole-based polymer is difficult to be processed into a molded product such as a membrane, and in many cases, even if a molded product is obtained, its shape cannot be maintained. It is considered that this is because, in addition to the chemical structure of the polymer main chain, only a polymer having a low degree of polymerization can be obtained by introducing an ionic group. Therefore, it has been difficult to obtain a polymer that can be used as a solid polymer electrolyte such as a proton exchange membrane.

[0021]

The object of the present invention is to introduce a sulfonic acid group or a phosphonic acid group into a polybenzazole compound having excellent properties such as heat resistance, solvent resistance and mechanical properties. Thus, a novel polymer material that can be a solid polymer electrolyte having excellent processability, solvent resistance, durability stability, and ion conductivity is obtained.

[0022]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that a specific polybenzazole compound containing a sulfonic acid group or a phosphonic acid group is excellently processed. It has been found that the polymer exhibits durability, durability, solvent resistance, mechanical properties, and ionic conductivity, and thus has obtained a novel polymer material satisfying the object of the present invention.

That is, the first aspect of the present invention is 2,2 '
A polybenzazole-based compound characterized by containing a disulfo-4,4′-biphenyldicarboxylic acid binding unit or a 3,3′-disulfo-4,4′-biphenyldicarboxylic acid binding unit.

The second invention of the present invention is a polybenzazole compound characterized by containing a binding unit represented by the following formula (1) and / or formula (2).

[0025]

[Chemical 4] (In the formulas (1) and (2), m ¹ is from 1 to 4
Represents an integer of, Ar represents an aromatic bond unit,
X ¹ is —SO ₂ — and Y ¹ represents an S atom or an O atom. )

Further, a third invention of the present invention is characterized in that it contains the polybenzazole compound described in either the first invention or the second invention as a main constituent. Is.

A fourth invention of the present invention is characterized by containing the polybenzazole compound described in any of the first to third inventions as a main constituent. Is.

A fifth invention of the present invention is a solid polymer electrolyte membrane characterized by containing the polybenzazole compound according to any one of the first to third inventions as a main constituent. Is.

Further, a sixth aspect of the present invention is a composite body comprising a solid polymer electrolyte membrane and electrode catalyst layers bonded to both surfaces of the solid polymer electrolyte membrane as constituent elements,
A solid polymer electrolyte membrane comprising the polybenzazole compound according to either the first invention or the second invention as a component constituting the solid polymer electrolyte membrane and / or the electrode catalyst layer. / A composite of electrode catalyst layers.

The seventh invention of the present invention is a composite comprising a solid polymer electrolyte membrane and electrode catalyst layers bonded to both surfaces of the solid polymer electrolyte membrane as constituent elements, wherein the solid polymer electrolyte membrane As a component that constitutes the polymer electrolyte membrane and / or the electrode catalyst layer, a binding unit represented by the following formulas (3) and (4) is included as a component in a molar ratio of n ¹ : (1-n ¹ ). A solid polymer electrolyte membrane / electrode catalyst layer composite comprising a polybenzazole compound.

[0031]

[Chemical 5] (In the formulas (3) and (4), m ² is from 1 to 4
Represents an integer of, Ar represents an aromatic bond unit,
X ² is _{-O -, - SO 2 -,} - C (CH 3) 2 -, - C (C
F _{3) 2} -, - OPhO- is from the group consisting one or more selected, Ph denote the divalent aromatic bond unit. Further, the molar ratio satisfies the formula of 0.2 ≦ n ¹ ≦ 1.0. )

Further, an eighth invention of the present invention is a composite body comprising a solid polymer electrolyte membrane and electrode catalyst layers bonded to both surfaces of the solid polymer electrolyte membrane as constituent elements,
A polybenzazole-based compound characterized by containing a binding unit selected from the following formulas (5) to (8) as a component constituting the solid polymer electrolyte membrane and / or the electrode catalyst layer. And a solid polymer electrolyte membrane / electrode catalyst layer composite.

[0033]

[Chemical 6] (In formulas (5) to (8), m³Is an integer from 1 to 4
Represents the number, Ar represents an aromatic bond unit, X³
Is -O-, -SO₂-, -S-, -CO-, -CH ₂-,
-OPhO- is one or more selected from the group consisting of:
Y²Is an NH group, an S atom, or an O atom, and Z is an S atom.
Is a child or O atom, and Ph is a divalent aromatic bond unit.
And R represents an H atom or a methyl group.
To do. ).

The ninth invention of the present invention is that the polybenzazole compound, which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer, has a logarithmic viscosity measured in concentrated sulfuric acid of 0.25 to 10 dl. The solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of the sixth to eighth inventions, which satisfies the condition of being in the range of / g.

The tenth invention of the present invention is the sulfonic acid group-containing polybenzazole compound, which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer, at 80 ° C.
It is necessary to meet the condition that the electric conductivity obtained by measuring the AC impedance when a voltage of 10,000 Hz is applied under the condition of 95% RH is in the range of 0.01 to 1.0 S / cm. It is a solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of the sixth, seventh, and ninth inventions.

The eleventh aspect of the present invention is the phosphonic acid group-containing polybenzazole compound, which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer, at 80 ° C.
It is necessary to satisfy the condition that the electric conductivity obtained by measuring the AC impedance when a voltage of 10,000 Hz is applied under the condition of 95% RH is in the range of 0.001 to 1.0 S / cm. A composite of a solid polymer electrolyte membrane / electrode catalyst layer according to any one of the eighth and ninth inventions characterized.

The twelfth aspect of the present invention is the N-type polybenzazole compound, which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer, under 170 ° C. conditions.
The solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of the sixth to eleventh inventions, which satisfies the condition that the solubility in methylpyrrolidone is 5% (w / w) or more. is there.

The thirteenth aspect of the present invention is that the polybenzazole compound, which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer, has a molecular weight of 1.5 meq / g.
It has the above sulfonic acid groups and / or phosphonic acid groups, and the decrease in mass when immersed in water at 25 ° C. for 72 hours is 0.
To 5% (w / w), the solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of the sixth to twelfth inventions.

Further, a fourteenth aspect of the present invention is a polybenzazole compound having a sulfonic acid group, which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer,
In thermogravimetric measurement, the sixth, seventh, ninth, and ninth characteristics are characterized in that the condition that the 3% mass reduction temperature is in the range of 370 to 550 ° C. is satisfied when the mass at the time of temperature increase of 200 ° C. is used as a reference. A solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of the tenth, twelfth, and thirteenth inventions.

A fifteenth aspect of the present invention is a polybenzazole-based compound having a phosphonic acid group, which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer,
Eighth, ninth, and first characterized by satisfying the condition that the 3% mass decrease temperature is in the range of 400 to 550 ° C when the mass at the time of temperature increase of 200 ° C is used as a reference in thermogravimetric measurement.
A solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of the first, twelfth, and thirteenth inventions.

The sixteenth invention of the present invention is a composite body comprising a step of adhering a solid polymer electrolyte membrane and electrode catalyst layers bonded to both surfaces of the solid polymer electrolyte membrane with a binder. A manufacturing method, wherein the solid polymer electrolyte membrane and / or the electrode catalyst layer contains the polybenzazole compound according to any one of the sixth to fifteenth inventions as a constituent component, and the binder also from the sixth. A method for producing a solid polymer electrolyte membrane / electrode catalyst layer composite, comprising the polybenzazole compound according to any one of the fifteenth invention as a constituent component.

[0042]

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

The polybenzazole compound having a sulfonic acid group and / or phosphonic acid group of the present invention (also referred to herein simply as the polybenzazole compound of the present invention) is not only durable but also processed. It is a new material that exhibits excellent properties in terms of properties and ionic conductivity. Since it has such excellent properties, the polybenzazole compound of the present invention can be suitably used as a material for a solid polymer electrolyte membrane for fuel cells.

The present invention comprises aromatic dicarboxylic acid binding units having sulphonic acid groups and / or phosphonic acid groups and has an inherent viscosity of 0.25 to 10 as measured in concentrated sulfuric acid.
It is preferable to use a polybenzazole compound having a basic structure, which satisfies the condition of being in the range of dl / g.

Here, a benzazole-based binding unit which is a constituent element of the polybenzazole-based compound of the present invention, an aromatic dicarboxylic acid binding unit having a sulfonic acid group and / or a phosphonic acid group, and a sulfonic acid group and a phosphonic acid group. It is preferable that the aromatic dicarboxylic acid bond unit having no group and the other bond units are bonded by random polymerization and / or alternating polymerization. Further, these polymerization forms are not limited to one kind, and two or more kinds of polymerization forms may coexist in the same compound.

<Polybenzazole-based compound> The polybenzazole-based compound having a sulfonic acid group and / or phosphonic acid group of the present invention means a polybenzimidazole-based compound having a sulfonic acid group and / or a phosphonic acid group, At least one selected from the group consisting of benzoxazole compounds and polybenzthiazole compounds is shown.

The route for synthesizing these compounds is not particularly limited, but usually, aromatic tetramines, aromatic diamine diols and aromatic diamine dithiols capable of forming an imidazole ring, an oxazole ring and a thiazole ring in the compound. And at least one compound selected from the group consisting of derivatives thereof and one or more compounds selected from the group consisting of aromatic dicarboxylic acids and their derivatives.

In this case, the aromatic dicarboxylic acid and / or its derivative used contains an aromatic dicarboxylic acid having a sulfonic acid group and / or a phosphonic acid group and / or
Alternatively, by partially mixing and using the derivative, a sulfonic acid group and / or a phosphonic acid group can be introduced into the obtained polybenzazole compound. At this time, the sulfonic acid group and / or phosphonic acid group in the aromatic dicarboxylic acid and / or its derivative may have a salt structure with an alkali metal or the like.

<Aromatic Tetramines, Diaminediols, Diaminedithiols> Aromatic tetramines used when synthesizing a polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group in the present invention,
The aromatic diamine diols, aromatic diamine dithiols and their derivatives are not particularly limited, but include, for example, 2,5-dihydroxyparaphenylenediamine, 4,6-dihydroxymetaphenylenediamine and 2,5 -Diamino-1,4-benzenedithiol, 4,6-diamino-1,3-benzenedithiol, 2,5-diamino-3,6-dimethyl-1,4-benzenedithiol, 1,2,4,5- Tetraaminobenzene, 3,3'-dihydroxybenzidine, 3,3'-
Diamino-4,4'-diphenylbenzenediol,
3,3'-dimercaptobenzidine, 3,3'-diamino-4,4'-diphenylbenzenedithiol, 3,
3'-diaminobenzidine, bis (4-amino-3-hydroxyphenyl) ether, bis (3-amino-4-)
Hydroxyphenyl) ether, bis (4-amino-3)
-Mercaptophenyl) ether, bis (3-amino-
4-mercaptophenyl) ether, 3,3 ′, 4
4'-tetraaminodiphenyl ether, bis (4-amino-3-hydroxyphenyl) thioether, bis (3-amino-4-hydroxyphenyl) thioether, bis (4-amino-3-mercaptophenyl) thioether, bis (3- Amino-4-mercaptophenyl) thioether, 3,3 ′, 4,4′-tetraaminodiphenylthioether, bis (4-amino-3-hydroxyphenyl) sulfone, bis (3-amino-4-hydroxyphenyl) sulfone, Bis (4-amino-3-
Mercaptophenyl) sulfone, bis (3-amino-4)
-Mercaptophenyl) sulfone, 3,3 ', 4,4'
-Tetraaminodiphenyl sulfone, 2,2-bis (4
-Amino-3-hydroxyphenyl) propane, 2,2
-Bis (3-amino-4-hydroxyphenyl) propane, 2,2-bis (4-amino-3-mercaptophenyl) propane, 2,2-bis (3-amino-4-mercaptophenyl) propane, 2, 2-bis (3,4-diaminophenyl) propane, bis (4-amino-3-hydroxyphenyl) methane, bis (3-amino-4-hydroxyphenyl) methane, bis (4-amino-3-mercaptophenyl) Methane, bis (3-amino-4-mercaptophenyl) methane, bis (3,4-diaminophenyl) methane, 2,2-bis (4-amino-3-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-Amino-4-hydroxyphenyl) hexafluoropropane, 2,2-bis (4-amino-3-mercaptophenyl) hexyl Fluoropropane, 2,2-bis (3-amino-4-mercaptophenyl) hexafluoropropane, 2,2-bis (3,4-diaminophenyl) hexafluoropropane, 2,2-bis (4-amino-3) -Hydroxyphenyl) ketone, 2,2-bis (3-amino-4-hydroxyphenyl) ketone, 2,
2-bis (4-amino-3-mercaptophenyl) ketone, 2,2-bis (3-amino-4-mercaptophenyl) ketone, 2,2-bis (3,4-diaminophenyl) ketone, bis (4 -Amino-3-hydroxyphenoxy) benzene, bis (3-amino-4-hydroxyphenoxy) benzene, bis (4-amino-3-mercaptophenoxy) benzene, bis (3-amino-4-mercaptophenoxy) benzene, bis (3,4, -diaminophenoxy) benzene and the like and derivatives thereof.

Specific examples of the derivatives of these aromatic tetramines, aromatic diamine diols and aromatic diamine dithiols include salts with acids such as hydrochloric acid, sulfuric acid and phosphoric acid. Further, these compounds may be used alone or in combination of two or more at the same time. Furthermore, these compounds may optionally contain known antioxidants such as tin (II) chloride and phosphorous acid compounds.

<Aromatic Dicarboxylic Acid Having Sulfonic Acid Group> Aromatic dicarboxylic acid having a sulfonic acid group used when synthesizing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention, and the same The derivative is not particularly limited, and a compound having 1 to 4 sulfonic acid groups in the aromatic dicarboxylic acid skeleton can be preferably used. As a specific example, 2,5-dicarboxybenzene sulfonic acid, 3,
5-dicarboxybenzenesulfonic acid, 2,5-dicarboxy-1,4-benzenedisulfonic acid, 4,6-dicarboxy-1,3-benzenedisulfonic acid, 2,2'-
Disulfo-4,4'-biphenyldicarboxylic acid, 3,
Mention may be made of aromatic dicarboxylic acids having sulfonic acid groups such as 3'-disulfo-4,4'-biphenyldicarboxylic acid and derivatives thereof. 2,2'-Disulfo-4,4'-biphenyldicarboxylic acid, 3,3'-disulfo-4,4'-biphenyldicarboxylic acid and derivatives thereof can be mentioned as preferable examples.

Here, examples of the sulfonic acid derivative of the aromatic dicarboxylic acid having these sulfonic acid groups include alkali metal salts such as sodium and potassium, ammonium salts, and alkylammonium salts. Further, these compounds may be used alone,
It is possible to use more than one at the same time. Furthermore, these compounds may optionally contain known antioxidants such as tin (II) chloride and phosphorous acid compounds.

The purity of the aromatic dicarboxylic acid having a sulfonic acid group used in the synthesis of the polybenzazole compound of the present invention is not particularly limited, but is preferably 98% or more, more preferably 99% or more. . The polybenzazole-based compound polymerized from an aromatic dicarboxylic acid having a sulfonic acid group as a raw material has a polymerization degree higher than that when an aromatic dicarboxylic acid having no sulfonic acid group and a phosphonic acid group is used as a raw material. Since it tends to be lower,
The aromatic dicarboxylic acid having a sulfonic acid group is preferably as pure as possible. That is, when the purity of the aromatic dicarboxylic acid is less than 98%, the degree of polymerization of the obtained polybenzazole compound tends to be low, and the polybenzazole compound tends to be unsuitable as a material for the solid polymer electrolyte.

Although the above-mentioned aromatic dicarboxylic acids having a sulfonic acid group may be used alone, they can be used in the present invention by copolymerization reaction with an aromatic dicarboxylic acid having no sulfonic acid group and phosphonic acid group. It may be used for the synthesis of a polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group. The aromatic dicarboxylic acid having no sulfonic acid group and phosphonic acid group that can be used together with the aromatic dicarboxylic acid having a sulfonic acid group is not particularly limited, but, for example,
Reported as polyester raw materials such as terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, biphenyl dicarboxylic acid, terphenyl dicarboxylic acid, 2,2-bis (4-carboxyphenyl) hexafluoropropane Common aromatic dicarboxylic acids can be used.

Further, these compounds may be used alone, or a plurality of them may be used at the same time. Furthermore, these compounds may optionally contain known antioxidants such as tin (II) chloride and phosphorous acid compounds.

In the synthesis of the polybenzazole compound of the present invention, when an aromatic dicarboxylic acid having no sulfonic acid group and no phosphonic acid group is used together with an aromatic dicarboxylic acid having a sulfonic acid group, a wholly aromatic dicarboxylic acid is used. By blending so that the content of the aromatic dicarboxylic acid having a sulfonic acid group therein is 20 mol% or more,
The excellent effect of the polybenzazole compound of the present invention having a sulfonic acid group can be clarified.
Further, in order to bring out the remarkable effect of the polybenzazole compound of the present invention having a sulfonic acid group, the content of the aromatic dicarboxylic acid having a sulfonic acid group is blended so as to be 50 mol% or more. Is more preferable. When the content of the aromatic dicarboxylic acid having a sulfonic acid group is less than 20 mol%, the conductivity of the polybenzazole-based compound of the present invention decreases and the polybenzazole compound of the present invention tends to be unsuitable as a material for a solid polymer electrolyte. There is.

<Aromatic Dicarboxylic Acid Having Phosphonic Acid Group> Aromatic dicarboxylic acid having a phosphonic acid group used in synthesizing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention and the same. The derivative is not particularly limited, and a compound having 1 to 4 phosphonic acid groups in the aromatic dicarboxylic acid skeleton can be preferably used. Specific examples include 2,5-dicarboxyphenylphosphonic acid, 3,
Mention may be made of aromatic dicarboxylic acids having phosphonic acid groups such as 5-dicarboxyphenylphosphonic acid and 2,5-bisphosphonoterephthalic acid, and derivatives thereof.

Examples of the phosphonic acid derivative of the aromatic dicarboxylic acid having these phosphonic acid groups include alkali metal salts such as sodium and potassium, ammonium salts and the like. Further, these compounds may be used alone or in combination of two or more at the same time. Furthermore, these compounds may optionally contain known antioxidants such as tin (II) chloride and phosphorous acid compounds.

The structure of the aromatic dicarboxylic acid having a phosphonic acid group is not limited to these, but the aromatic dicarboxylic acid having a phenylphosphonic acid group type phosphonic acid group as shown here is preferable. .

The purity of the aromatic dicarboxylic acid having a phosphonic acid group used in the synthesis of the polybenzazole compound of the present invention is not particularly limited, but is preferably 97% or more, more preferably 98% or more. The polybenzazole-based compound polymerized from an aromatic dicarboxylic acid having a phosphonic acid group as a raw material has a polymerization degree higher than that when an aromatic dicarboxylic acid having no sulfonic acid group and a phosphonic acid group is used as a raw material. Since it tends to be low, it is preferable to use the aromatic dicarboxylic acid having a phosphonic acid group as high in purity as possible. That is, when the purity of the aromatic dicarboxylic acid is less than 97%, the degree of polymerization of the obtained polybenzazole-based compound tends to be low, and it tends to be unsuitable as a material for the solid polymer electrolyte.

Although the above aromatic dicarboxylic acids having a phosphonic acid group may be used alone, they can be used in the present invention by copolymerization reaction with an aromatic dicarboxylic acid having no sulfonic acid group and phosphonic acid group. It may be used for the synthesis of a polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group. The sulfonic acid group and the aromatic dicarboxylic acid having no phosphonic acid group that can be used together with the aromatic dicarboxylic acid having a phosphonic acid group are not particularly limited, for example,
Reported as polyester raw materials such as terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, biphenyl dicarboxylic acid, terphenyl dicarboxylic acid, 2,2-bis (4-carboxyphenyl) hexafluoropropane Common aromatic dicarboxylic acids can be used.

Further, these compounds may be used alone, or a plurality of them may be used at the same time. Furthermore, these compounds may optionally contain known antioxidants such as tin (II) chloride and phosphorous acid compounds.

When an aromatic dicarboxylic acid having a phosphonic acid group and an aromatic dicarboxylic acid having no sulfonic acid group or phosphonic acid group are used in the synthesis of the polybenzazole compound of the present invention, a wholly aromatic dicarboxylic acid is used. By blending so that the content of the aromatic dicarboxylic acid having a phosphonic acid group therein is 20 mol% or more,
It is possible to clarify the excellent effect of the polybenzazole compound of the present invention having a phosphonic acid group.
Further, in order to bring out the remarkable effect of the polybenzazole compound of the present invention having a phosphonic acid group, the content of the aromatic dicarboxylic acid having a phosphonic acid group is blended so as to be 50 mol% or more. Is more preferable. When the content of the aromatic dicarboxylic acid having a phosphonic acid group is less than 20 mol%, the conductivity of the polybenzazole compound of the present invention tends to be low and the polybenzazole compound of the present invention tends to be unsuitable as a material for a solid polymer electrolyte. There is.

Here, the above-mentioned aromatic dicarboxylic acid having a sulfonic acid group and aromatic dicarboxylic acid having a phosphonic acid group may be used alone, but they are not It may be used for the synthesis of the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the invention.

At this time, although the above-mentioned aromatic dicarboxylic acid having a sulfonic acid group and aromatic dicarboxylic acid having a phosphonic acid group may be used alone, they may have a sulfonic acid group and a phosphonic acid group. It may be used for the synthesis of the polybenzazole-based compound having a sulfonic acid group and / or a phosphonic acid group of the present invention by performing a copolymerization reaction with an aromatic dicarboxylic acid not contained.

<Synthesis Method of Polybenzazole Compound> The above-mentioned aromatic tetramines, aromatic diamine diols,
One or more compounds selected from the group consisting of aromatic diaminedithiols and their derivatives, and one or more compounds selected from the group consisting of aromatic dicarboxylic acids and their derivatives (hereinafter collectively referred to simply as raw material monomers) The method for synthesizing a polybenzazole-based compound having a sulfonic acid group and / or a phosphonic acid group using) is not particularly limited.
lfe, Encyclopedia of Polymer Science and Engineeri
ng, 2nd Ed., Vol. 11, P. 601 (1988), and can be synthesized by dehydration and cyclopolymerization using polyphosphoric acid as a solvent. It is also possible to apply polymerization by a similar mechanism using a methanesulfonic acid / phosphorus pentoxide mixed solvent system instead of polyphosphoric acid. In addition, in order to synthesize a polybenzazole-based compound having high thermal stability, polymerization using polyphosphoric acid, which is commonly used, is preferable.

Further, to obtain a polybenzimidazole compound as the polybenzazole compound of the present invention,
For example, a precursor polymer having a polyamide structure or the like has been synthesized by a reaction in a suitable organic solvent or in the form of a mixed raw material monomer melt, and then a cyclization reaction such as an appropriate heat treatment gives a desired polyimidazole structure. A conversion method or the like can also be used.

Further, the reaction time for synthesizing the polybenzazole compound of the present invention cannot be unconditionally defined because there is an optimum reaction time depending on the combination of individual raw material monomers, but it has been reported so far. In a reaction containing a raw material monomer such as an aromatic dicarboxylic acid having a sulfonic acid group and / or a phosphonic acid group in a reaction that takes a long time, the thermal stability of the obtained polybenzazole compound may decrease. Therefore, in this case, it is preferable to shorten the reaction time within the range in which the effect of the present invention can be obtained. By shortening the reaction time in this way, a polybenzazole compound having a large amount of sulfonic acid groups can also be obtained in a highly heat stable state.

The reaction temperature at the time of synthesizing the polybenzazole compound of the present invention cannot be unconditionally defined because there is an optimum reaction temperature depending on the combination of individual raw material monomers, but it has been reported so far. In the reaction at high temperature, in a system containing a raw material monomer such as an aromatic dicarboxylic acid having a sulfonic acid group and / or a phosphonic acid group, introduction of the sulfonic acid group and / or phosphonic acid group into the obtained polybenzazole compound In some cases, it becomes impossible to control the amount. In this case, it is preferable to lower the reaction temperature within the range where the effect of the present invention can be obtained. By lowering the reaction temperature in this way, the sulfonic acid groups and //
Alternatively, it is possible to control the introduction amount of the phosphonic acid group.

Further, when the raw material monomers which constitute the repeating unit after the synthesis of the polybenzazole compound of the present invention are composed of a plurality of kinds, the repeating units are randomly polymerized and / or alternated. By being bonded by polymerization, it has a characteristic of exhibiting stable performance as a material for the polymer electrolyte membrane.

Here, in order to synthesize the polybenzazole compound of the present invention by a polymerization method of random polymerization and / or alternating polymerization, all the monomer raw materials are charged from the initial stage of the polymerization at a compounding ratio in which equivalence is adjusted. It is preferable to make it by the placing method.

The polybenzazole compound can be synthesized by block polymerization instead of random polymerization or alternating polymerization, but in that case, it is necessary to prepare the poly (benzazole) -based compound under the conditions of charging the monomer raw materials in a mixing ratio with a stoichiometric deviation. It is preferable to synthesize an oligomer of the component, further add a monomer raw material, adjust the compounding ratio including the second component so that the equivalence is satisfied, and then perform the polymerization.

<Molecular Weight of Polybenzazole Compound and Logarithmic Viscosity> The molecular weight of the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is not particularly limited, but is 1,000. It is preferably not less than 3,000, more preferably not less than 3,000. The molecular weight is preferably 1,000,000 or less, more preferably 200,000 or less. When the molecular weight is less than 1,000, it becomes difficult to obtain a molded article having good properties from the polybenzazole compound due to the reduced viscosity. Further, if the molecular weight exceeds 1,000,000, it becomes difficult to mold the polybenzazole compound due to the increase in viscosity.

The molecular weight of the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention can be evaluated substantially by the logarithmic viscosity when measured in concentrated sulfuric acid. The logarithmic viscosity is 0.
It is preferably 25 or more, and more preferably 0.40 or more. The logarithmic viscosity is preferably 10 or less, more preferably 8 or less.

When the logarithmic viscosity is less than 0.25,
The decrease in viscosity makes it difficult to obtain a molded article having good properties from the polybenzazole compound. Further, if the molecular weight exceeds 10, it becomes difficult to mold the polybenzazole compound due to the increase in viscosity.

<Electrical Conductivity of Polybenzazole Compound> One of the characteristics of the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is that it has excellent ionic conductivity. Polybenzazole-based compound containing an aromatic dicarboxylic acid-bonding unit having a sulfonic acid group as a constituent (in the present specification,
(Also referred to as a polybenzazole-based compound having a sulfonic acid group) exhibits even more excellent ionic conductivity.

The polybenzazole-based compound having a sulfonic acid group and / or a phosphonic acid group of the present invention has, in addition to the above basic characteristics, a conductivity measured by a measuring method described below (hereinafter The rate shall be measured by the same measurement method), and the conductivity obtained by measuring the AC impedance when a voltage of frequency 10,000 Hz is applied under the conditions of 80 ° C. and 95% RH (hereinafter, The electric conductivity) is preferably 0.001 S / cm or more, and more preferably 0.01 S / cm or more. Further, this conductivity is preferably 1.0 S / cm or less, and more preferably 0.90 S / cm or less.

When the conductivity is less than 0.01 S / cm, there is a tendency that sufficient ionic conductivity cannot be obtained when used as a material for a solid polymer electrolyte membrane used in a fuel cell, and the conductivity is 1 or less. In order to exceed 0.0 S / cm, an excessive amount of sulfonic acid group and / or sulfonic acid group must be introduced into the polybenzazole compound, and as a result, the material of the solid polymer electrolyte membrane used in the fuel cell. When used as, there is a tendency that sufficient durability cannot be obtained.

<Polybenzazole Compound Having Sulfonic Acid Group> In addition to the above basic characteristics, the polybenzazole compound of the present invention has a benzoxazole-based binding unit and / or a benzthiazole-based binding unit. Containing an aromatic dicarboxylic acid unit having a sulfonic acid group, and having a conductivity of 0.02 S /
More preferably, it is at least cm. In this case, the polybenzazole compound of the present invention can be more suitably used as a material for a solid polymer electrolyte membrane used in a fuel cell.

Further, the polybenzazole compound of the present invention comprises, in addition to the above-mentioned basic characteristics, a benzoxazole-based binding unit and / or a benzthiazole-based binding unit, and at least one or more benzoxazole-based binding units in the molecule. It contains an aromatic dicarboxylic acid bond unit having a sulfonic acid group and has a logarithmic viscosity of 0.2 as measured with a concentrated sulfuric acid solution.
It is more preferably 5 dl / g or more and the conductivity is 0.2 S / cm or more. In this case, the polybenzazole compound of the present invention can be more preferably used as a material for a solid polymer electrolyte membrane used in a fuel cell.

Further, a polybenzazole-based compound characterized by containing a binding unit represented by the following formula (1) and / or formula (2) is particularly preferable.

[0082]

[Chemical 7] (In the formulas (1) and (2), m ¹ is from 1 to 4
Represents an integer of, Ar represents an aromatic bond unit,
X ¹ is —SO ₂ — and Y ¹ represents an S atom or an O atom. )

It is also particularly preferable that the compound is a polybenzazole compound containing the binding units represented by the following formulas (3) and (4) in a molar ratio of n ¹ : (1-n ¹ ). As an example:

[0084]

[Chemical 8] (In the formulas (3) and (4), m ² is from 1 to 4
Represents an integer of, Ar represents an aromatic bond unit,
X ² is _{-O -, - SO 2 -,} - C (CH 3) 2 -, - C (C
F _{3) 2} -, - OPhO- is from the group consisting one or more selected, Ph denote the divalent aromatic bond unit. Further, the molar ratio satisfies the formula of 0.2 ≦ n ¹ ≦ 1.0. )

<Polybenzazole Compound Having Phosphonic Acid Group> The polybenzazole compound of the present invention has, in addition to the above basic characteristics, an aromatic dicarboxylic acid-bonding unit having a phosphonic acid group as a constituent element. As a polybenzazole-based compound (also referred to as a polybenzazole-based compound having a phosphonic acid group in the present specification) and having a conductivity of 0.001 S / cm or more. Is also more preferable. Even in this case, the polybenzazole compound of the present invention has excellent ionic conductivity, and can be more suitably used as a material for a solid polymer electrolyte membrane used in a fuel cell.

In this case, the phosphonic acid group that can be introduced into the polybenzazole compound of the present invention is not particularly limited, but for example, 2,5-dicarboxyphenylphosphonic acid and 3,5-dicarboxylic acid can be used. A phosphonic acid group that can be introduced into a polybenzazole-based compound by using a raw material monomer composed of an aromatic dicarboxylic acid having a phosphonic acid such as carboxyphenylphosphonic acid and 2,5-bisphosphonoterephthalic acid, and derivatives thereof. Is mentioned. The structure of the phosphonic acid group of the polybenzazole-based compound having a phosphonic acid group is not particularly limited, but a phenylphosphonic acid group type as shown here is preferable.

The polybenzazole-based compound having a phosphonic acid group of the present invention contains a benzoxazole-based binding unit as a main constituent, and also contains an aromatic dicarboxylic acid binding unit having a phosphonic acid group, and It is even more preferable that the conductivity is 0.01 S / cm or more. In this case, the polybenzazole compound of the present invention can be used more suitably as a material for a solid polymer electrolyte membrane used in a fuel cell.

The polybenzazole compound having a phosphonic acid group of the present invention preferably contains no fluorine atom. This is because the polybenzazole compound having a phosphonic acid group of the present invention can exhibit excellent durability, heat resistance, water resistance and mechanical strength without containing a fluorine atom, and also contains a fluorine atom. Is because the manufacturing process tends to be complicated, and the manufacturing cost tends to be disadvantageous. Further, when the fluorine atom is contained, the resistance to methanol tends to be lowered, which tends to be disadvantageous as a solid electrolyte membrane for fuel cells.
Similarly, it is preferable that the following polybenzazole-based compound having a phosphonic acid group of the present invention does not contain a fluorine atom.

Further, the following equations (5) to (8)
A polybenzazole-based compound characterized by containing a binding unit selected from the above is particularly preferable.

[0090]

[Chemical 9] (In formulas (5) to (8), m ³ represents an integer of 1 to 4, Ar represents an aromatic bond unit, and X ³
, - - -O is _{SO 2 -, - S -,} - CO -, - CH 2 -,
-OPhO- is one or more selected from the group consisting of:
Y ² is an NH group, an S atom or an O atom, Z is an S atom or an O atom, Ph represents a divalent aromatic bond unit, and R represents an H atom or a methyl group. )

<Solubility in Organic Solvent> In addition to the above basic characteristics, the polybenzazole-based compound of the present invention contains a polyimidazole-based binding unit as a constituent and has a sulfonic acid group and / or a phosphon group. A polybenzazole compound containing an aromatic dicarboxylic acid-bonding unit having an acid (also referred to herein simply as a polyimidazole compound having a sulfonic acid group and / or a phosphonic acid), and N-methylpyrrolidone By satisfying the conditions that the solubility in (herein also simply referred to as NMP) is 5% (w / w) and the logarithmic viscosity measured in concentrated sulfuric acid is 0.25 dl / g or more. It will be even more preferable.

The polybenzazole compound generally has low solubility and often dissolves only in a strongly acidic solvent. Then, when producing a solid polymer electrolyte membrane, if the membrane is formed by a wet method from a strongly acidic solution, the membrane structure tends to become non-uniform, and a solid polymer electrolyte membrane that maintains stable performance can be produced. difficult. On the other hand, when the polybenzazole compound is soluble in an organic solvent such as NMP,
A membrane can be formed by a dry method, and a solid polymer electrolyte membrane that is homogeneous and exhibits stable membrane performance for a long period of time can be relatively easily produced.

Therefore, in this case, since the polybenzazole compound of the present invention has excellent solubility in NMP, it can be said that it is a polymer material having excellent moldability and ionic conductivity. It can be more suitably used as the material of the electrolyte membrane. The solubility of the polybenzazole compound of the present invention in NMP is 5% (w
If less than / w), a large amount of solvent is required to obtain a solid polymer electrolyte membrane having a desired thickness, and thus the uniformity of the membrane tends to be impaired.

<Reduction of Mass by Immersion in Water> The polybenzazole compound of the present invention has a sulfonic acid group and / or phosphonic acid group of 1.5 meq / g or more in the molecule in addition to the above basic characteristics. However, it is even more preferable that the mass reduction (hereinafter referred to simply as mass decrease due to water immersion) when immersed in water at 25 ° C. for 72 hours is 5% or less. In this case, since the polybenzazole-based compound of the present invention has a mass reduction of 5% or less due to immersion in water, the polybenzazole-based compound does not deteriorate in physical properties due to dissolution or swelling of the polybenzazole-based compound, and a solid polymer electrolyte used in a fuel cell. It can be used more suitably as a material for the film.

<Mass Reduction Due to Heat> Generally, the sulfonic acid group and / or phosphonic acid group bonded to the aromatic ring is
Desulphonic acid reaction and / or dephosphonic acid reaction due to heat easily occur. Therefore, sulfonic acid groups and /
In addition, many aromatic polymers having a phosphonic acid group have poor thermal stability.

In general, the ionic conductivity becomes higher as the amount of sulfonic acid groups and / or phosphonic acid groups in the polymer increases, but thermal decomposition is caused in a polymer having sulfonic acid groups and / or phosphonic acid groups. Is initiated by the elimination reaction of the sulfonic acid group and / or the phosphonic acid group, the thermal decomposition temperature decreases as the amount of the sulfonic acid group and / or the phosphonic acid group increases. So far, no known technique has been disclosed that can solve this problem at a sufficiently satisfactory level, and therefore it has excellent ionic conductivity and heat resistance that can be used as a material for the solid polymer electrolyte membrane. Obtaining a polymer material still exists as an unsolved problem in this technical field.

On the other hand, the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is characterized by being excellent in thermal stability. That is, the polybenzazole-based compound of the present invention has a conductivity of 0.01 S / cm or more, in addition to the above basic characteristics, and a temperature of 200 ° C. in thermogravimetric measurement (abbreviated as TGA in the present specification). 3% based on the sample mass at the time of temperature rise
It is even more preferable that the mass reduction temperature (hereinafter referred to simply as 3% mass reduction temperature) is 370 ° C. or higher. Further, it is even more preferable if the 3% mass reduction temperature is 400 ° C. or higher, and most preferably 440 ° C. or higher.

In this case, since the polybenzazole compound of the present invention is particularly excellent in ionic conductivity and heat resistance, it can be more suitably used as a material for a solid polymer electrolyte membrane used in a fuel cell. It can be said that the above-mentioned publicly known techniques solve the unsolved problems.

The polybenzazole compound of the present invention which is excellent in thermal stability is a polybenzazole having a phosphonic acid group in addition to the above basic characteristics,
It is even more preferable if the condition that the% mass reduction temperature is 400 ° C. or higher is satisfied. Further, if the 3% mass reduction temperature is 420 ° C. or higher, it is even more preferable.
Most preferably, it is 0 ° C or higher. Also in this case, the polybenzazole-based compound of the present invention is particularly excellent in ionic conductivity and heat resistance, so that it can be further suitably used as a material for a solid polymer electrolyte membrane used in a fuel cell. It can be said that the above-mentioned publicly-known techniques solve the unsolved problems.

Further, among the above-mentioned polybenzazole compounds having a phosphonic acid group excellent in thermal stability, NM
A polybenzazole compound having a solubility in P of 5% (w / w) or more is even more preferable. In this case, the polybenzazole-based compound of the present invention is particularly excellent in durability stability at high temperature as well as processability, so that it can be further suitably used as a material for a solid polymer electrolyte membrane used in a fuel cell. . Further, in addition to the excellent solubility in NMP, it can be said that the polybenzazole-based compound is more preferably a polybenzimidazole-based compound.

Then, these phosphonic acid group-containing polybenzazole compounds excellent in durability at high temperature and processability are
A polybenzazole-based compound having an electrical conductivity of 0.001 S / cm or more is more preferable because it has excellent ion conductivity in addition to durability and processability at high temperatures. .

<Polybenzimidazole Compound Having Sulfonic Acid Group> Among the polybenzazole compounds of the present invention described above, in addition to the above basic characteristics, a polybenzimidazole compound having a sulfonic acid group is also provided. It is particularly preferable to include a polybenzazole-based compound containing a binding unit represented by the following formulas (3) and (4) at a molar ratio of n ¹ : (1-n ¹ ) as a constituent.

[0103]

[Chemical 10] (In the formulas (3) and (4), m ² is from 1 to 4
Represents an integer of, Ar represents an aromatic bond unit,
X ² is _{-O -, - SO 2 -,} - C (CH 3) 2 -, - C (C
F _{3) 2} -, - OPhO- is from the group consisting one or more selected, Ph denote the divalent aromatic bond unit. Further, the molar ratio satisfies the formula of 0.2 ≦ n ¹ ≦ 1.0. )

In the above formula (3), the Ar unit having a sulfonic acid group is 2,2'-disulfo-4,4 '.
-Biphenyldicarboxylic acid binding unit or 3,3 '
It is further preferable that it is a -disulfo-4,4'-biphenyldicarboxylic acid unit. In these cases, the polybenzazole-based compound of the present invention is excellent in durability stability at high temperature as well as solvent resistance and mechanical strength, so that it can be more suitably used as a material for a solid polymer electrolyte membrane used in a fuel cell. It will be

When n ¹ = 1.0, the polybenzazole compound of the present invention is a homopolymer in which all repeating units contain a sulfonic acid group. Further, in the polybenzimidazole compound having a sulfonic acid group which is excellent in solvent stability and mechanical strength as well as durability stability at high temperature as described above, when m ² ≧ 4, high ion conductivity while maintaining water resistance is obtained. It becomes difficult to maintain the sex.

Here, as aromatic tetramines which can be used as a raw material monomer of a benzimidazole-based binding unit having a structure represented by the formula (3) or (4) contained as a constituent element of the polybenzazole-based compound of the present invention, Is
Although not particularly limited, for example, 3,3 ′,
4,4'-tetraaminodiphenyl ether, 3,
3 ', 4,4'-tetraaminodiphenylthioether, 3,3', 3,3 ', 4,4'-tetraaminodiphenylmethane, 4,4'-tetraaminodiphenylsulfone, 2,2-bis (3,3 4-diaminophenyl) propane, 2,2-bis (3,4-diaminophenyl) hexafluoropropane, bis (3,4, -diaminophenoxy) benzene and the like and derivatives thereof. Specific examples of these derivatives include salts with acids such as hydrochloric acid, sulfuric acid and phosphoric acid.

Here, these aromatic tetramines are
Although they may be used alone, a plurality of them may be used simultaneously. In addition, these aromatic tetramines may contain a known antioxidant such as tin (II) chloride or a phosphorous acid compound, if necessary.

The aromatic dicarboxylic acid having a sulfonic acid group which can be a raw material monomer of the benzimidazole-based binding unit having the structure of the formula (3) is not particularly limited, and the aromatic dicarboxylic acid It is possible to use compounds which contain 1 to 4 sulphonic acid groups.

Specific examples include 2,5-dicarboxybenzenesulfonic acid, 3,5-dicarboxybenzenesulfonic acid, 2,5-dicarboxy-1,4-benzenedisulfonic acid and 4,6-dicarboxy- Aromatic dicarboxylic acids having sulfonic acids such as 1,3-benzenedisulfonic acid, 2,2'-disulfo-4,4'-biphenyldicarboxylic acid, and 3,3'-disulfo-4,4'-biphenyldicarboxylic acid And their derivatives. Specific examples of these derivatives include alkali metal salts such as sodium and potassium, ammonium salts, and the like.

Here, although these aromatic dicarboxylic acids having a sulfonic acid group may be used alone, they have a sulfonic acid group which can be a raw material monomer of a benzimidazole-based binding unit having the structure of formula (22). Not react with aromatic dicarboxylic acid in the form of copolymerization,
The polybenzazole compound of the present invention can be synthesized.

The aromatic dicarboxylic acid having no sulfonic acid group which can be used in the synthesis of the polybenzazole compound of the present invention together with the aromatic dicarboxylic acid having a sulfonic acid group is not particularly limited. However, for example, polyesters such as terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, biphenyl dicarboxylic acid, terphenyl dicarboxylic acid, 2,2-bis (4-carboxyphenyl) hexafluoropropane A general aromatic dicarboxylic acid reported as a raw material can be used.

The purity of the aromatic dicarboxylic acid having a sulfonic acid group is not particularly limited, but is 98%.
The above is preferable, and 99% or more is more preferable. A polyimidazole compound polymerized using an aromatic dicarboxylic acid having a sulfonic acid group as a raw material monomer tends to have a lower degree of polymerization than a case where an aromatic dicarboxylic acid having no sulfonic acid group is used. Therefore, it is preferable to use an aromatic dicarboxylic acid having a sulfonic acid group, which is as pure as possible.

Furthermore, when an aromatic dicarboxylic acid having no sulfonic acid group is used together with an aromatic dicarboxylic acid having a sulfonic acid group, the aromatic dicarboxylic acid having a sulfonic acid group is used in an amount of 20 mol based on the total aromatic dicarboxylic acid. When the content is at least%, the excellent effect of the polybenzazole-based compound having a sulfonic acid group of the present invention as a material used for a solid polymer electrolyte membrane used for a fuel cell can be clarified. And, in order to bring out the above-mentioned effects of the polybenzazole-based compound having a sulfonic acid group of the present invention in a remarkable manner, the aromatic dicarboxylic acid having a sulfonic acid group is added in an amount of 50 mol% in the wholly aromatic dicarboxylic acid. It is more preferable to set it as above.

To reiterate, the polybenzimidazole compound having a sulfonic acid group of the present invention is excellent in durability, solvent resistance and mechanical properties. For example, durability has a low molecular weight reduction due to hydrolysis in hot water, solvent resistance has low swelling in an acidic aqueous solution, and mechanical properties include rupture even when handled as a thin film. It is excellent in that you do not have to worry.

<Resin Composition> The polybenzazole-based compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is obtained even if the polybenzazole compound of the present invention is added alone as a main component to the resin composition. Can be suitably used as a material for a solid polymer electrolyte membrane used in a fuel cell. But,
The polybenzazole-based compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is not limited to being used alone, and may be blended as a main component with other polymers in the same manner to obtain the resin composition. The product can be suitably used as a material for a solid polymer electrolyte membrane used in a fuel cell. Examples of these polymers include polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, nylon 6,
Polyamides such as nylon 6,6, nylon 6,10, and nylon 12, polymethyl methacrylate, polymethacrylic acid esters, acrylate resins such as polymethyl acrylate, polyacrylic acid esters, polyacrylic acid resin, polymethacryl Acid resins, polyethylene, polypropylene, various polyolefins including polystyrene and diene polymers, polyurethane resins, cellulose acetate, cellulose resins such as ethyl cellulose, polyarylate, aramid, polycarbonate, polyphenylene sulfide, polyphenylene oxide, polysulfone, polyether sulfone , Polyetheretherketone, polyetherimide, polyimide, polyamideimide, polybenzimidazole, polybenzoxazole, polyben Aromatic polymers, such as thiazole, epoxy resins, phenolic resins, novolak resins,
The thermosetting resin such as benzoxazine resin is not particularly limited. When used as these resin compositions, the polybenzazole compound of the present invention is preferably contained in an amount of 50% by weight or more and less than 100% by weight of the entire resin composition. It is more preferably 70% by weight or more and less than 100% by weight. When the content of the polybenzazole-based compound of the present invention is less than 50% by weight of the entire resin composition, the sulfonic acid group concentration of the ion conductive membrane containing this resin composition becomes low and good ion conductivity is obtained. In addition, the unit containing a sulfonic acid group becomes a discontinuous phase, and the mobility of the ion to be conducted tends to decrease. In addition,
The composition of the present invention optionally contains, for example, an antioxidant,
It may contain various additives such as a heat stabilizer, a lubricant, a tackifier, a plasticizer, a cross-linking agent, a viscosity modifier, an antistatic agent, an antibacterial agent, a defoaming agent, a dispersant and a polymerization inhibitor.

Here, as a polymer which can be blended with the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention, a polybenzazole compound having no ionic group (in the present specification, , And also referred to simply as a polybenzazole-based compound having no ionic group). The polybenzazole-based compound having no ionic group means an aromatic polyoxazole, an aromatic polythiazole, an aromatic polyimidazole, a composition in which they are mixed, or a copolymer thereof. .

That is, the resin composition of the present invention contains the polybenzazole compound having the sulfonic acid group and / or the phosphonic acid group of the present invention and the polybenzazole compound having no ionic group. It should be noted that the resin composition of the present invention also includes a resin composition consisting of a polybenzazole-based compound having a sulfonic acid group and / or a phosphonic acid group of the present invention alone.

The polybenzazole compound having no ionic group, which can be blended in the resin composition of the present invention, generally contains a repeating unit having a structure represented by the following formula (9) as a constituent element. It is a polybenzazole compound.

[0119]

[Chemical 11] (Here, in the formula (9), R ¹ represents a tetravalent aromatic bond unit capable of forming an azole ring, X represents an O atom,
Represents an S atom or NH group. R ² represents a divalent aromatic bond unit. Each of R ¹ and R ² may be a monocyclic aromatic ring, may be a combination of a plurality of aromatic rings or a condensed ring, and may have a stable substituent. Further, both R ¹ and R ² may have a heterocyclic structure in which N atom, S atom, O atom and the like are present in the aromatic ring. )

The polybenzazole compound having no ionic group, which can be blended in the resin composition of the present invention, can also be shown as a repeating unit having a structure represented by the following formula (10). .

[0121]

[Chemical 12] (Here, in the formula (10), X represents an O atom, an S atom, or an NH group. Further, R ³ represents a trivalent aromatic bond unit capable of forming an azole ring.)

The polybenzazole compound having no ionic group, which can be incorporated into the resin composition of the present invention, is a repeating unit composed of a bonding unit having a structure represented by both formula (9) and formula (10). It may be a polybenzazole compound containing both units as constituent elements.

The polybenzazole compound having no ionic group, which can be blended in the resin composition of the present invention, is not particularly limited, but for example, poly {(benz [1,2-d: 5,4-d '] bisoxazole-2,
6-diyl) -1,4-phenylene}, poly {(benz [1,2-d: 4,5-d '] bisoxazole-2,
6-diyl) -1,4-phenylene}, poly {(benz [1,2-d: 5,4-d '] bisthiazole-2,6
-Diyl) -1,4-phenylene}, poly {(benz [1,2-d: 4,5-d '] bisthiazole-2,6
-Diyl) -1,4-phenylene}, poly {(benz [1,2-d: 5,4-d '] bisimidazole-2,
6-diyl) -1,4-phenylene}, poly {(benz [1,2-d: 4,5-d '] bisimidazole-2,
6-diyl) -1,4-phenylene}, poly {2,2 '
-(P-phenylene) -6,6'-bibenzoxazole}, poly {2,2 '-(m-phenylene) -6,6'
-Bibenzoxazole}, poly {2,2 '-(p-phenylene) -6,6'-bibenzthiazole}, poly {2,2'-(m-phenylene) -6,6'-bibenzthiazole }, Poly {2,2 '-(p-phenylene)-
6,6'-Vibenzimidazole}, poly {2,2'-
(M-phenylene) -6,6'-bibenzimidazole}, poly (2,6-benzoxazole), poly (2,5-benzoxazole), poly (2,6-benzthiazole), poly (2, 5-benzthiazole),
Poly (2,6-benzimidazole), poly (2,5-
Benzimidazole) and the like. And among these compounds, poly {(benz [1,2
-D: 5,4-d '] bisoxazole-2,6-diyl) -1,4-phenylene}, poly {(benz [1,2]
-D: 4,5-d '] bisoxazole-2,6-diyl) -1,4-phenylene}, poly {(benz [1,2]
-D: 5,4-d '] bisthiazole-2,6-diyl) -1,4-phenylene}, poly {(benz [1,2]
-D: 4,5-d '] bisthiazole-2,6-diyl) -1,4-phenylene}, poly (2,6-benzoxazole), poly (2,5-benzoxazole),
Poly (2,6-benzthiazole), poly (2,5-benzthiazole), and the like are particularly preferable as the polybenzazole-based compound having no ionic group that can be compounded in the resin composition of the present invention.

The degree of polymerization of the polybenzazole compound having no ionic group, which can be blended in the resin composition of the present invention, has a logarithmic viscosity of 0.5 d when measured in methanesulfonic acid.
The polymerization degree is preferably 1 / g or more,
It is more preferable that the polymerization degree be 1 dl / g or more. The degree of polymerization is such that the logarithmic viscosity is 50 dl /
The degree of polymerization is preferably not more than g, 30
It is more preferable that the polymerization degree be dl / g or less. When the degree of polymerization is such that the logarithmic viscosity is less than 0.5 dl / g, the moldability and mechanical properties of the resin composition tend to deteriorate, and the logarithmic viscosity is 50 dl / g.
When the degree of polymerization exceeds, the processability of the resin composition tends to decrease.

The content of the polybenzazole compound having no ionic group in the resin composition of the present invention is preferably 1% by mass or more based on the mass of the entire resin composition, and 10% by mass. The above is more preferable. Also,
This content is preferably 99% by mass or less, and 5
It is more preferably 0% by mass or less, and most preferably 30% by mass or less. When the content is less than 1% by mass, moldability and mechanical properties tend to be deteriorated, and when the content exceeds 99% by mass, properties as a polymer electrolyte, which is the original purpose, tends to be deteriorated. There is.

As the method for mixing the polybenzazole compound having a sulfonic acid group and / or phosphonic acid group of the present invention with another polymer, any known method can be used. For example, both can be dissolved in an appropriate solvent and mixed, melt-kneaded, crushed and mixed, but the invention is not limited thereto.

Among these mixing methods, the method of dissolving the both in a solvent and mixing them is preferable in view of simplicity of the manufacturing process, manufacturing cost and quality. Specifically, a solution in which both are dissolved may be mixed, or both may be mixed and dissolved at once.

In this case, the solvent for dissolving both is
Use aprotic polar solvents such as N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone and hexamethylphosphonamide, and strong acids such as polyphosphoric acid, methanesulfonic acid, sulfuric acid and trifluoroacetic acid. However, the present invention is not limited to these. Further, these solvents may be used alone, or a plurality of solvents may be mixed and used within a possible range. Furthermore, as a means for improving the solubility of both,
As a solvent that dissolves both, a solvent obtained by adding a Lewis acid such as lithium bromide, lithium chloride, or aluminum chloride to an organic solvent may be used.

In the above solution, the total concentration of the polybenzazole compound having a sulfonic acid group and / or phosphonic acid group of the present invention and the other polymer is 0.1.
It is preferably at least mass%, more preferably at least 0.5 mass%. Further, the total concentration is preferably 50% by mass or less, and more preferably 30% by mass or less. If the total concentration is less than 0.1% by mass, the moldability of the resin composition tends to decrease,
If the total concentration exceeds 50% by mass, the processability of the resin composition tends to decrease.

<Resin Molded Product> The resin molded product of the present invention contains the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention.

That is, the resin molded product of the present invention comprises a resin composition containing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention, or a solution prepared by dissolving the resin composition, It can be produced by molding into a shape such as a fiber or a film by any known molding method such as extrusion, spinning, rolling and casting.

Among these molding methods, the method of molding from a solution of the resin composition of the present invention dissolved in a suitable solvent is preferable. Therefore, since the resin molded product of the present invention is molded from the resin composition of the present invention, it necessarily contains the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention.

Here, as the solvent for dissolving the resin composition of the present invention, N, N-dimethylacetamide, N, N-
Aprotic polar solvents such as dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, hexamethylphosphonamide, polyphosphoric acid, methanesulfonic acid,
A suitable acid can be selected from strong acids such as sulfuric acid and trifluoroacetic acid, but is not particularly limited thereto.

Further, these solvents may be used alone, or a plurality of them may be mixed and used within a possible range. Further, as a means for improving the solubility of the resin composition of the present invention, a solvent obtained by adding a Lewis acid such as lithium bromide, lithium chloride or aluminum chloride to an organic solvent may be used.

Here, the concentration of the resin composition of the present invention in the solution is preferably 0.1% by mass or more, and 1% by mass.
The above is more preferable. Further, this concentration is preferably 50% by mass or less, and more preferably 30% by mass or less. If the concentration is less than 0.1% by mass, the moldability of the resin molded product tends to decrease, and if this concentration exceeds 50% by mass, the processability of the resin molded product tends to decrease.

Further, as a method for obtaining a resin molded product from a solution containing the resin composition of the present invention, a known molding method can be used. For example, the polybenza having a sulfonic acid group and / or a phosphonic acid group is removed by removing the solvent by heating, drying under reduced pressure, immersion in a non-solvent that can mix with the solvent that dissolves the resin composition but hardly dissolves the resin composition A resin molded product containing a resin composition containing a sol-based compound can be obtained.

When the solvent for dissolving the resin composition of the present invention is an organic solvent, it is preferable that the solvent be distilled off by heating or drying under reduced pressure. When the solvent is a strong acid, it is preferably immersed in water, methanol, acetone or the like. At this time, if necessary, it may be formed into a fiber or film in a form of being combined with another resin composition. For example, when combined with a resin composition containing a polybenzazole compound having a similar solubility behavior, it is convenient for good molding.

<Solid Polymer Electrolyte Membrane> The solid polymer electrolyte membrane of the present invention contains the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention.

Since the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention has excellent ion conductivity, it is used in the form of a film or a film and used as an ion exchange membrane of a fuel cell or the like. Suitable for
Therefore, the solid polymer electrolyte membrane of the present invention also has excellent ionic conductivity and is suitable for use as an ion exchange membrane for fuel cells and the like.

The solid polymer electrolyte membrane of the present invention can be obtained by molding a resin composition containing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention.

Here, a preferable method for forming a film containing a resin composition containing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention as a main component is the resin composition of the present invention. Is a cast from a solution containing. The solvent can be removed from the cast solution as described above to obtain a film containing a resin composition containing a polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group.

In this case, it is preferable that the solvent is removed by drying in terms of the uniformity of the film. Further, in order to prevent decomposition and alteration of the resin composition and the solvent, it is preferable to dry under reduced pressure at the lowest possible temperature. A glass plate, a polytetrafluoroethylene plate, or the like can be used as the substrate to be cast. When the viscosity of the solution is high, heating the substrate or the solution and casting at a high temperature lowers the viscosity of the solution, so that the solution can be easily cast.

Further, in this case, the thickness of the solution at the time of casting (also referred to simply as casting thickness in the present specification) is not particularly limited, but is preferably 10 μm or more, and more preferably 100 μm or more. The thickness is preferably 1000 μm or less, and more preferably 500 μm or less. If the thickness is less than 100 μm, the film obtained from the cast solution tends to lose its shape, and the thickness is 1
When it exceeds 000 μm, a non-uniform film tends to be easily formed.

Further, as a method for controlling the cast thickness of this solution, a known control method can be used.
For example, although not particularly limited, the cast thickness is made constant by using an applicator, a doctor blade or the like, or the cast area is made constant by using a glass petri dish or the like, and the cast thickness is controlled at a constant amount or concentration of the solution. can do.

A more uniform film can be obtained by adjusting the solvent removal rate of the thus cast solution. For example, when heating, the evaporation rate can be lowered by lowering the temperature in the first step.
When immersed in a non-solvent such as water, the coagulation rate of the polymer can be adjusted by leaving the solution in air or an inert gas for an appropriate time.

The solid polymer electrolyte membrane of the present invention may have any thickness depending on the purpose, but it is preferably as thin as possible from the viewpoint of ion conductivity. Specifically, it is preferably 200 μm or less, more preferably 50 μm or less, and most preferably 20 μm or less.

On the other hand, the solid polymer electrolyte membrane of the present invention can have any thickness depending on the purpose, but it is preferably as thick as possible from the viewpoint of mechanical strength. Specifically, it is preferably 5 μm or more, more preferably 10 μm or more, and most preferably 20 μm or more.

The film according to the present invention is excellent in durability, solvent resistance and mechanical properties. For example, durability is such that deterioration at high temperatures is low, solvent resistance is low in swelling in an acidic aqueous solution, and mechanical properties are such that there is no risk of breakage during handling even when the film is thin. Further, by using the polymer structure of the present invention as a main component, it can be used as a coating material for a binder resin or the like when producing a bonded body of the ion exchange membrane of the present invention and an electrode.

<Compound of Solid Polymer Electrolyte Membrane / Electrode Catalyst Layer of the Present Invention> A resin composition containing a polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is a solid polymer. In a solid polymer electrolyte / electrode catalyst layer composite composed of an electrolyte membrane and electrode catalyst layers bonded to both surfaces thereof, the solid polymer electrolyte membrane and //
Alternatively, it can be suitably used as a constituent component of the electrode catalyst layer.

At this time, the sulfonic acid group of the present invention and /
Alternatively, the polybenzazole-based compound having a phosphonic acid group has a molecular weight of 1.5 meq /
It is preferable to have g or more sulfonic acid groups and / or phosphonic groups.

The solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention is a polybenzazole in which the solid polymer electrolyte membrane and / or electrode catalyst layer has a sulfonic acid group and / or a phosphonic acid group of the present invention. It is characterized by containing a system compound.

In the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention, both the solid polymer electrolyte membrane and the electrode catalyst layer have the sulfonic acid group and / or phosphonic acid group of the present invention. It is preferable that the main component is a polybenzazole compound.

In the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention, the binder for adhering the solid polymer electrolyte membrane and the electrode catalyst layer is a sulfonic acid group and / or phosphonic acid of the present invention. It is more preferable to contain a polybenzazole compound having a group.

The logarithmic viscosity in sulfuric acid of the above binder containing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is 0.1 dl / g or more. Preferably 0.3
More preferably, it is dl / g or more. The logarithmic viscosity is preferably 10 dl / g or less,
More preferably, it is 1 / g or less.

In the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention, as the solid polymer electrolyte membrane, “Nafion (registered trademark)” manufactured by DuPont, “Dow membrane” manufactured by Dow Chemical Co., Ltd. , Asahi Glass "Flemion (registered trademark)", Asahi Kasei "Aciplex (registered trademark)", Gore-Tex Inc. "Goreselect (registered trademark)" and other existing perfluorocarbon sulfonic acid-based high Molecular electrolytes, sulfonated polyether sulfones, sulfonated polyether ketones, polybenzimidazoles impregnated with strong acids such as phosphoric acid and sulfuric acid, and polybenzazole compounds having a sulfonic acid group and / or phosphonic acid group of the present invention A polymer electrolyte containing is preferably used. Further, as these polymer electrolyte membranes, solid polymer electrolyte membranes containing a plurality of these polymer electrolytes can be used as long as the ion conductivity is not significantly impaired.

Further, as the polymer electrolyte membrane used in the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention, other than the polybenzazole-based compound having a sulfonic acid group and / or a phosphonic acid group of the present invention, You may use the solid polymer electrolyte membrane produced by mixing polymers.
As a polymer to be mixed, a polyazole-based polymer is preferable because it has excellent compatibility.

The polymer electrolyte membrane used in the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention is a resin composition containing various polymer electrolytes, which is dissolved in a solution and cast, and then dried or It can be obtained by any known molding method such as dipping in a non-solvent to remove the solvent or molding such a solution or resin composition by hot pressing, rolling or extrusion.

Here, the thickness of the solid polymer electrolyte membrane used in the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention is preferably 5 μm or more, and more preferably 10 μm or more. Also, this thickness is 300μ
It is preferably m or less, and more preferably 100 μm or less.

When the solid polymer electrolyte membrane used in the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention is molded, a polybenzazole system having a sulfonic acid group and / or a phosphonic acid group of the present invention is used. It is preferable that the resin composition containing the compound is dissolved in a solvent to be molded.

In this case, the solvent suitable for dissolving the resin composition containing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is not particularly limited. , For example, aprotic polar solvents such as dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and hexamethylphosphonamide; Examples thereof include nitrated compounds and strong acids such as polyphosphoric acid, sulfuric acid, methanesulfonic acid, ethanesulfonic acid, chlorosulfonic acid and trifluoroacetic acid. Further, although these solvents may be used alone, the solid polymer electrolyte membrane of the present invention /
You may mix and use two or more in the range which does not have a bad influence on the characteristic of the solid polymer electrolyte membrane used in the composite of an electrode catalyst layer.

Further, among these solvents, aprotic polar solvents such as dimethylacetamide are preferable.
Then, the aprotic polar solvent is aluminum chloride, in order to improve the solubility of the polymer and the stability of the solution,
A Lewis acid such as lithium chloride or lithium bromide may be added. Further, when the content of the sulfonic acid group and / or phosphonic acid group of the polybenzoxazole or polybenzthiazole having a sulfonic acid group and / or phosphonic acid group of the present invention is high, the solubility in an aprotic polar solvent is increased. Therefore, it is more preferable.

The solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention can be obtained by hot pressing a catalyst metal and a binder onto the solid polymer electrolyte membrane, or by using a commercially available gas diffusion electrode with the sulfonic acid of the present invention. By spraying or coating a polymer electrolyte including a polybenzazole-based compound having a phosphonic acid group and / or a phosphonic acid group and allowing it to permeate, and by sandwiching and bonding the solid polymer electrolyte membrane Obtainable.

Further, the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention comprises a resin film of polytetrafluoroethylene, polypropylene, polyethylene, polyethylene terephthalate or the like, and the polymer electrolyte and catalyst as a solvent. It is also possible to obtain a laminate in which pastes that have been uniformly dispersed are repeatedly applied and dried to sandwich the solid polymer electrolyte membrane with the catalyst layer on the inside and perform hot pressing to join them.

Further, the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention is a brush, a brush, an applicator, a sprayer, a printer, etc., prepared by using a paste obtained by uniformly dispersing the polymer electrolyte and the catalyst in a solvent. It can also be obtained by applying a solvent to the solid polymer electrolyte membrane by the method described above, and then drying the solvent to bond it. It can also be obtained by joining an electrode material such as carbon paper and a polymer electrolyte membrane with such a paste. In these methods, the ionic group may be previously prepared as an alkali metal salt such as Na, and the acid may be returned to the original acid by an acid treatment after bonding. Alternatively, the catalyst can be directly bonded to the solid polymer electrolyte membrane by sputtering or the like.

Further, when the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is used as the polymer electrolyte, the above solvent can be used. At this time, the concentration of the polymer electrolyte in the solution or paste is preferably 0.1% by mass or more, and more preferably 1% by mass or more. Further, this concentration is preferably 50% by mass or less, and more preferably 30% by mass or less.

In the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention, the catalyst used in the electrode catalyst layer is preferably a conductive material carrying fine particles of catalytic metal, and contains other components. You may stay. This catalytic metal is preferably a noble metal containing platinum as a main component, and may contain other metals such as rhodium, palladium, gold, silver, iridium, and ruthenium.

The particle size of this catalyst is preferably 1 nm or more, more preferably 5 nm or more. The particle size of this catalyst is preferably 50 nm or less, and more preferably 30 nm or less.

Further, in the electrode catalyst layer used in the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention, the amount of the catalyst relative to the polymer electrolyte is preferably 50% by mass or more, and 70% by mass or more. It is more preferable if The amount of this catalyst is preferably 1,000% by mass or less, more preferably 500% by mass or less.

Other components in the electrode catalyst layer used in the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention are not particularly limited, but, for example, polytetrafluoroethylene as a binder, Examples thereof include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and tetrafluoroethylene-hexafluoroethylene copolymer.

The hot pressing conditions for molding the electrode catalyst layer used in the solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention can be selected appropriately depending on the material used, but are favorable. In order to obtain moldability, the hot press temperature is preferably 100 ° C or higher, and 1
More preferably, it is 50 ° C. or higher. The temperature of the hot press is preferably 300 ° C or lower, and 250 ° C.
The following is more preferable. The pressure of the hot press is preferably 1 MPa or higher, more preferably 2 MPa or higher. The pressure of hot press is 1
It is preferably 0 MPa or less, and more preferably 7 MPa or less.

[0171]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

In this specification, various measurements and evaluations were performed as follows. (I) Measurement of Logarithmic Viscosity of Solution in Concentrated Sulfuric Acid A sample polymer was dissolved in concentrated sulfuric acid to a concentration of 0.5 g / dl, and viscosity was measured using an Ostwald viscometer in a constant temperature bath at 30 ° C. , Logarithmic viscosity [ln (ta / t
b)] / c was obtained and evaluated (ta is the number of seconds of dropping the sample solution, tb is the number of seconds of dropping only the solvent, and c is the polymer concentration (g.
/ Dl)).

(Ii) Measurement of ionic conductivity A platinum wire (diameter: 0.2 mm) was pressed against the surface of the strip-shaped membrane sample on a self-made measuring probe (made of polytetrafluoroethylene), and 80 ° C., 95% RH. Constant temperature and humidity oven (Nagano Scientific Machinery Co., Ltd., LH-20-01)
Hold the sample inside and measure the AC impedance at 10 KHz between the platinum wires by SOLARTRON 1250FRE.
It was measured by QUENCY RESPONSE ANALYSER. The measurement was performed while changing the distance between the electrodes, and the conductivity in which the contact resistance between the film and the platinum wire was canceled was calculated from the gradient obtained by plotting the distance between the electrodes and the measured resistance value by the following formula. Conductivity [S / cm] = 1 / film width [cm] × film thickness [cm]
× Resistance gap between electrodes [Ω / cm]

(Iii) Determination of Solubility in N-Methylpyrrolidone 10.00 g of N-methylpyrrolidone in a 50 ml flask.
Then, 0.50 g of the sample polymer was taken, stirred in a 170 ° C. oil bath under a nitrogen atmosphere for 3 hours, and filtered through a 1G2 glass filter. If no residue was visually observed on the filter, the solubility was determined to be 5% or more.

(Iv) Measurement of mass reduction by immersion in water 100 mg of a sample polymer was added to 10 ml of ion-exchanged water for 2 minutes.
After soaking at 5 ° C for 3 days, the residue was filtered through a 1G2 glass filter. After filtration, the filter was dried under reduced pressure at 80 ° C. overnight, and the mass of the residue was determined from the mass before and after filtration to determine the mass reduction rate.

(V) Evaluation of hot water resistance When the membrane sample was immersed in boiling water for 1 hour, it was visually judged whether the morphology of the membrane changed due to swelling or dissolution.

(Vi) Evaluation of Durability The sample polymer was immersed in a sealed ampoule in water at 100 ° C. and left for 3 days, and the logarithmic viscosity of the solution before and after the treatment was measured as described above. The durability was evaluated from the change in the measured value.

(Vii) Measurement of 3% mass decrease temperature by TGA TGA-50 manufactured by Shimadzu Corporation was used for measurement by TGA.
Was used to measure about 5 mg of a sample that is a polymer having substantially no salt-forming sulfonic acid group and / or phosphonic acid group under an argon atmosphere. The temperature was raised to 150 ° C. at 10 ° C./min, held for 30 minutes to remove water in the sample, and further measured to 600 ° C. at 10 ° C./min. The temperature at the time when 3% of the mass of the sample at the time of raising the temperature by 200 ° C. decreased was defined as 3% mass decrease temperature.

(Viii) Measurement of IR spectrum The IR spectrum of the sample polymer was measured by a microscopic transmission method using FTS-40 manufactured by Biorad as a spectroscope and UMA-300A manufactured by Biorad as a microscope.

Synthesis Example 1 First, 1.500 g of 3,3 ′, 4,4′-tetraaminodiphenyl sulfone (abbreviation: TAS, purity 99%)
(Corresponding to 5.389 × 10 ⁻³ mol), monosodium 2,5-dicarboxybenzenesulfonate (abbreviation: ST)
A, purity 99%) 1.445 g (5.389 × 10 ⁻³ m)
ol), polyphosphoric acid (phosphorus pentoxide content 75% by mass), 20.48 g (0.1082 mo as phosphorus pentoxide)
equivalent to 1), 16.41 g of phosphorus pentoxide (0.1156 m
(corresponding to ol) was weighed into a polymerization vessel. Next, nitrogen was flown into the polymerization vessel, and the temperature was raised to 100 ° C. while slowly stirring on an oil bath. Then, after holding at 100 ° C. for 1 hour, the temperature was raised to 150 ° C. for 1 hour, and the temperature was raised to 200 ° C. for 4 hours for polymerization. After the completion of the polymerization, the mixture was allowed to cool, water was added to take out the polymer, and washing with water was repeated using a household mixer until the pH test paper became neutral. The obtained polymer was dried under reduced pressure at 80 ° C. overnight. The inherent viscosity of the obtained polymer in concentrated sulfuric acid was 1.35 dl / g. Moreover, the result of having measured the IR spectrum of the obtained polymer is shown in FIG. From the results of the IR spectrum shown in FIG. 1, it is found that the polybenzimidazole in which the sulfonic acid group is introduced according to the present invention. Next, 400 mg of the obtained polymer and 4 ml of NMP were mixed and stirred and heated to 170 ° C. on an oil bath to be dissolved.
Then, the obtained solution was cast on a glass plate on a hot plate so as to have a thickness of about 200 μm to evaporate NMP. Then, the obtained film was peeled off from the glass plate, dried under reduced pressure at 80 ° C. overnight, and then immersed in acetone to remove the solvent, thereby producing a film used for measuring ion conductivity. Then, TGA measurement of the obtained film was performed. The TGA measurement chart obtained at this time is shown in FIG. From the result of FIG. 2, it can be seen that the 3% mass reduction temperature is 462 ° C. The ionic conductivity of the obtained film at 80 ° C. and 95% RH was 0.018 S / cm, and the measured ionic conductivity maintained stable performance for a long period of time. Further, the obtained film was immersed in boiling water for 1 hour, but no change in morphology was observed. Also, in water at 100 ℃ 3
The logarithmic viscosity after the immersion treatment for one day was 1.37 dl / g, and no change from that before the treatment was observed. Thickness 1
Even if a thin film of about 0 μm was formed, the film was not broken in the above various evaluations. Table 1 summarizes the above various measurement results and evaluation results.

[0181]

[Table 1] * 1: Logarithmic viscosity measured in concentrated sulfuric acid * 2: Logarithmic viscosity after hot water immersion storage * 3: Visual evaluation after hot water immersion

Synthesis Example 2 STA and terephthalic acid (abbreviation: TP) instead of STA
5.389 × 10 ⁻³ mo in total by changing the mixing ratio of A)
A polymer was polymerized in the same manner as in Synthesis Example 1 except that the mixture was charged so that the amount became 1. Then, various measurements and various evaluations were performed. As a result of various measurements and various evaluations, ionic conductivity of all the samples was stable for a long period of time, and the morphology of the film was also kept good. Further, even if a thin film having a thickness of about 10 μm was produced, the film was not broken in the above various evaluations. Table 2 shows various measurement results and evaluation results.

[0183]

[Table 2] * 1: Logarithmic viscosity measured in concentrated sulfuric acid * 2: Logarithmic viscosity after hot water immersion storage * 3: Visual evaluation after hot water immersion

Synthesis Example 3 A polymer was polymerized in the same manner as in Synthesis Example 1 except that monosodium 3,5-dicarboxybenzenesulfonate (abbreviation: SIA, purity 98%) was used instead of STA.
A film was prepared and various measurements and various evaluations were performed. At this time, the IR spectrum of the obtained polymer when the charging ratio was adjusted so that TPA / SIA = 66/34 is shown in FIG. From the results of the IR spectrum shown in FIG. 3, it can be seen that it is the polybenzimidazole into which the sulfonic acid group of the present invention has been introduced. As a result of various measurements and various evaluations, ionic conductivity of all the samples was stable for a long period of time, and the morphology of the film was also kept good. Further, even if a thin film having a thickness of about 10 μm was produced, the film was not broken in the above various evaluations. Table 3 shows various measurement results and evaluation results.

[0185]

[Table 3] * 1: Logarithmic viscosity measured in concentrated sulfuric acid * 2: Logarithmic viscosity after hot water immersion storage * 3: Visual evaluation after hot water immersion

Synthetic Example 4 Synthetic Example 3 except that tin (II) chloride was added at 1 mol% to TAS at the time of polymerization to obtain a polymer.
The polymer was polymerized in the same manner as in 1. to form a film, and various measurements and various evaluations were performed. As a result of various measurements and various evaluations, the ionic conductivity of each sample was kept stable for a long period of time, and the morphology of the film was also kept good. Further, even if a thin film having a thickness of about 10 μm was produced, the film was not broken in the above various evaluations. Table 4 shows various measurement results and evaluation results.

[0187]

[Table 4] * 1: Logarithmic viscosity measured in concentrated sulfuric acid * 2: Logarithmic viscosity after hot water immersion storage * 3: Visual evaluation after hot water immersion

Comparative Synthesis Example 1 Instead of STA, 0.895 g of TPA (5.39 × 10 5)
⁽ Corresponding to ⁻³ mol) was used to polymerize the polymer in the same manner as in Example 1 to prepare a film, and various measurements and various evaluations were performed. As a result of various measurements and various evaluations, a polymer having an inherent viscosity of 2.11 dl / g in sulfuric acid was obtained. Also, the obtained film was immersed in boiling water for 1 hour, but no change in morphology was observed, and the logarithmic viscosity after immersion treatment in 100 ° C. water for 3 days was 2.06. I was not able to admit. Furthermore, 80
The ionic conductivity was measured at 95 ° C. and 95% RH, but it was not possible to capture the behavior of flowing ions. Even when a thin film having a thickness of about 10 μm was produced, the film was not broken in the above various evaluations. Table 5 shows various measurement results and evaluation results.

[0189]

[Table 5] * 1: Logarithmic viscosity measured in concentrated sulfuric acid * 2: Logarithmic viscosity after hot water immersion storage * 3: Visual evaluation after hot water immersion

Synthesis Example 5 1.05 g of TAS (3.773 × 10 ⁻³ mol), T
After polymerizing PA with 0.598 g (3.557 × 10 ⁻³ mol), the polymerization liquid was once cooled and then T
0.45 g (1.616 × 10 ^-3 mol) AS, ST
0.491 g (1.832 × 10 ⁻³ mol) of A was added, and the polymerization reaction was performed once again to give TPA / STA = 6.
A polymer was polymerized in the same manner as in Synthesis Example 1 except that a block copolymer satisfying the ratio of 6/34 was synthesized to prepare a film, and various measurements and various evaluations were performed. As a result of various measurements and various evaluations, the polymer obtained had an inherent viscosity of 0.86 dl / g in concentrated sulfuric acid, and a film could be prepared by the same method as in Example 1, but the temperature was 80 ° C., 95 Ionic conductivity at% RH is 0.0
The value was an order of magnitude smaller than that of the polymer of Example 2 having the same copolymerization ratio as 003 S / cm. Even when a thin film having a thickness of about 10 μm was produced, the film was not broken in the above various evaluations. Table 6 shows various measurement results and evaluation results.

[0191]

[Table 6] * 1: Logarithmic viscosity measured in concentrated sulfuric acid * 2: Logarithmic viscosity after hot water immersion storage * 3: Visual evaluation after hot water immersion

Synthesis Example 6 First, 1.830 g (6.575 × 1) of 3,3 ′, 4,4′-tetraaminodiphenyl sulfone (abbreviation: TAS) was prepared.
0 ^-3 corresponds to mol), 3,5-dicarboxyphenyl phosphonic acid (abbreviation: DCP, 98% purity) 1.618 g
(Equivalent to 6.575 × 10 ⁻³ mol), polyphosphoric acid (phosphorus pentoxide content 75 mass%) 20.48 g, phosphorus pentoxide 1
6.41 g was weighed into a polymerization vessel. Next, nitrogen was flown into the polymerization vessel, and the temperature was raised to 110 ° C. while slowly stirring on an oil bath. Then, after holding at 110 ° C. for 1 hour, the temperature was raised to 150 ° C. for 1 hour, and the temperature was raised to 200 ° C. for 5 hours for polymerization. After completion of the polymerization, the mixture was allowed to cool, water was added to take out the polymer, and the polymer was obtained by repeatedly washing with a household mixer until the pH test paper became neutral. The obtained polymer was dried under reduced pressure at 80 ° C. overnight. Here, the IR spectrum of the obtained polymer is shown in FIG. From the IR spectrum results shown in FIG. 4, it can be seen that the phosphonic acid group-introduced polybenzimidazole of the present invention is used. Subsequently, 300 mg of the obtained polymer and 2.5 ml of methanesulfonic acid were mixed at room temperature and stirred to obtain a uniform solution. Then, the obtained solution was cast on a glass plate on a hot plate so as to have a thickness of about 200 μm, allowed to stand at room temperature for 1 hour, and then immersed in water. After that, the water was occasionally changed, and the water immersion was continued for several days. After the immersion, the film was taken out, fixed around and air-dried while suppressing shrinkage. Finally, it was dried overnight at 80 ° C. in a vacuum dryer to prepare a membrane used for measuring ionic conductivity. As a result of various measurements and various evaluations using the obtained polymer, the logarithmic viscosity measured in concentrated sulfuric acid was 1.21 dl / g, and the 3% mass reduction temperature by TGA measurement was 440 ° C. Moreover, as a result of various measurements and various evaluations using the obtained membrane, the ionic conductivity at 80 ° C. and 95% RH shows 0.031 S / cm, and the measured ionic conductivity maintains stable performance for a long period of time. At the same time, the morphology of the film was well maintained. Further, even if a thin film having a thickness of about 10 μm was produced, the film was not broken in the above various evaluations. Table 7 shows various measurement results and evaluation results.

[0193]

[Table 7] * 1: Logarithmic viscosity measured in concentrated sulfuric acid * 2: Logarithmic viscosity after hot water immersion storage * 3: Visual evaluation after hot water immersion

Synthesis Example 7 Instead of DCP, DCP and terephthalic acid (abbreviation: TP)
By changing the mixing ratio of A), the total is 6.575 × 10 ⁻³ mo.
Polymerization was carried out in the same manner as in Synthesis Example 6 except that charging was performed so that the amount became 1. Then the polymer 400 obtained
mg and 4 ml of NMP were mixed and stirred, and heated to 170 ° C. on an oil bath to dissolve. Then, cast on a glass plate to a thickness of about 200 μm on a hot plate, and
The MP was evaporated. Then peel the film from the glass plate,
The film was dried under reduced pressure at 80 ° C. overnight and then immersed in acetone to prepare a film from which the solvent was removed. As a result of various measurements and various evaluations using the obtained polymer and membrane, the measured ionic conductivity of the obtained membrane maintained stable performance over a long period of time, and the morphology of the membrane was also kept good. Further, even if a thin film having a thickness of about 10 μm was produced, the film was not broken in the above various evaluations. Table 8 shows various measurement results and evaluation results.

[0195]

[Table 8] * 1: Logarithmic viscosity measured in concentrated sulfuric acid * 2: Logarithmic viscosity after hot water immersion storage * 3: Visual evaluation after hot water immersion

Example 1 First, smoke 30% of 4,4'-biphenyldicarboxylic acid
By stirring at 120 ° C with sulfuric acid, 2,2 '
-Disulfo-4,4'-biphenyldicarboxylic acid (abbreviated
The name: DSBC) was synthesized. Then, the reaction solution is hydroxylated
Treated with sodium, sulfonic acid group of sodium salt
The form, DSBC, was purified. Then, instead of STA
2.405 g of DSBC purified as described above (5.3
89 x 10 ^-3(equivalent to mol) except that
The polymer was polymerized in the same manner as in Example 1 to prepare a film,
Seed measurement and various evaluations were performed. Various measurements and evaluations
As a result of the valency, the ionic conductivity of all samples was long-term.
Keeps stable performance and keeps good film morphology
It was In addition, a thin film with a thickness of about 10 μm was prepared.
However, the film did not break in the above various evaluations
It was Table 9 shows various measurement results and evaluation results.

[0197]

[Table 9] * 1: Logarithmic viscosity measured in concentrated sulfuric acid * 2: Logarithmic viscosity after hot water immersion storage * 3: Visual evaluation after hot water immersion

Example 2 Bis (3-amino-4-hydroxyphenyl) sulfone (abbreviation: HAS) was used in place of TAS, and the aromatic dicarboxylic acid component was STA or SIA.
In the same manner as in Synthesis Example 1, various polymers were polymerized and synthesized. Next, 1.8 g of methanesulfonic acid was added to 0.12 g of the synthesized polymer sample and dissolved by stirring with a magnetic stirrer for several hours to obtain poly {(benzo [1,2-
3 g of 1% (w / w) methanesulfonic acid dope (intrinsic viscosity 24 dl / g) of d: 5,4-d '] bisoxazole-2,6-diyl) -1,4-phenylene} was added, and The solution was stirred for several hours to form a uniform solution. Then, about 225μ of the obtained solution on a hot plate on a glass plate.
The glass plate was cast to have a thickness of m and left at room temperature for 1 hour, and then the glass plate was immersed in water. After that, the water was occasionally changed, and the water immersion was continued for several days. After the immersion, the film was taken out, fixed around and air-dried while suppressing shrinkage. Finally, it was dried at 80 ° C. overnight with a vacuum dryer to prepare a membrane used for measuring ion conductivity. As a result of performing various measurements and various evaluations using the obtained polymer and film, the measured ionic conductivity maintains stable performance for a long time, and
The morphology of the film was also kept well. Further, even if a thin film having a thickness of about 10 μm was produced, the film was not broken in the above various evaluations. Table 1 shows various measurement results and evaluation results.
It shows in 0.

[0199]

[Table 10] * 1: Logarithmic viscosity measured in concentrated sulfuric acid

Example 3 0.2 g of the sulfonated polybenzimidazole compound, which is the polymer obtained in Synthesis Example 1, was dissolved in 2 ml of NMP at room temperature, and cast into a glass plate. After drying
Dipped in hot water to remove the solvent and dried again to a thickness of 22 μm
A solid polymer electrolyte membrane of was obtained. Next, the platinum loading is 2
0% (w / w) carbon black (particle size: 20
0.72 g) and a Nafion (registered trademark) solution (manufactured by DuPont: "Nafion (registered trademark) solution 20".
% ") To prepare a paste by uniformly mixing and dispersing 5 g of glycerin. Subsequently, the obtained paste was applied by spraying on one surface of the solid polymer electrolyte membrane and dried under reduced pressure.
Then, the paste was similarly applied to the other surface of the solid polymer electrolyte membrane and dried under reduced pressure. The amount of platinum carried in the obtained solid polymer electrolyte membrane / electrode catalyst layer composite was 0.5 m.
It was g / cm ² . Also, this solid polymer electrolyte membrane /
The conductivity of the composite of the electrode catalyst layer was measured to be 2.4 ×.
It was 10 ⁻⁶ S / cm.

Example 4 The polymer obtained in Synthesis Example 1, the sulfonated polymer
Dissolve 0.2 g of imidazole compound in 5 ml of NMP
I understand. The platinum loading in this solution is 20% (w / w)
Carbon black (particle size: 20 to 30 nm)
By mixing and dispersing 72 g of the mixture so that it is uniform,
I adjusted the taste. Then, paste the obtained paste
Solid polymer prepared in the same manner as in Example 3 by screen printing
It was applied to one surface of the electrolyte membrane and dried under reduced pressure. And
Paste the same on the other side of the solid polymer electrolyte membrane.
Was applied and dried under reduced pressure. Obtained solid polymer electrolyte membrane
/ The amount of platinum supported on the composite of the electrode catalyst layer is 0.5 mg / cm
²Met. In addition, this solid polymer electrolyte membrane / electrode catalyst
The conductivity of the layer composite was measured to be 9.3 x 10 ^-FiveS
Was / cm.

Example 5 In Synthesis Example 7, 0.2 g of the phosphonated polybenzimidazole compound obtained by TPA / DCP = 34/66 (molar ratio) was dissolved in 2 ml of NMP and cast into a glass plate to form a film. . After drying, soak in hot water to remove the solvent,
It was dried again to obtain a solid polymer electrolyte membrane having a thickness of 18 μm. Further, 0.75 g of carbon black (particle size: 20 to 30 nm) having a platinum loading of 20% (w / w) is homogenized in a solution of 0.2 g of the same phosphonated polybenzimidazole compound in 2 ml of NMP. The paste was prepared by mixing and dispersing as described above. Next, the obtained paste was applied to one surface of the solid polymer electrolyte membrane produced by screen printing, and dried under reduced pressure. Then, the paste was similarly applied to the other surface of the solid polymer electrolyte membrane and dried under reduced pressure. The amount of platinum supported on the obtained solid polymer electrolyte membrane / electrode catalyst layer composite was 0.
It was 4 mg / cm ² . In addition, the electric conductivity of the composite of the solid polymer electrolyte membrane / electrode catalyst layer was measured to be 3.
It was 3 × 10 ⁻⁵ S / cm.

[0203]

The polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention has excellent properties such as processability, solvent resistance, durability, heat resistance and mechanical properties. Since it is a compound in which a sulfonic acid group or a phosphonic acid group is introduced into a polybenzazole compound, it is excellent not only in processability, solvent resistance, durability, heat resistance and mechanical properties, but also in ion conductivity. Therefore, the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention can be suitably used as a polymer material for a solid polymer electrolyte membrane.

Further, the resin composition containing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention is not limited to processability, solvent resistance, durability, heat resistance and mechanical properties. Since it also has excellent ionic conductivity, it can be suitably used as a polymer material for a solid polymer electrolyte membrane used in a fuel cell or the like.

A resin molded product containing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention can also be processed, solvent-resistant, durable, solvent-resistant and mechanically. Since it is also excellent in ion conductivity, it can be suitably used as a polymer material for a solid polymer electrolyte membrane used in a fuel cell or the like.

Further, the solid polymer electrolyte membrane containing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention also has only processability, solvent resistance, durability, heat resistance and mechanical properties. In addition, since it has excellent ionic conductivity, it can be suitably used as a main member such as a fuel cell.

The solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention comprises, as constituent elements, the solid polymer electrolyte membrane and the electrode catalyst layers bonded to both sides of the solid polymer electrolyte membrane. Since it is a composite, and the solid polymer electrolyte membrane and / or the electrode catalyst layer contains the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention as a constituent, Solvent-based,
It is excellent not only in durability, heat resistance and mechanical properties but also in ionic conductivity and can be suitably used as a main member for fuel cells and the like.

In addition, according to the method for producing a solid polymer electrolyte membrane / electrode catalyst layer composite of the present invention, the solid polymer electrolyte membrane and the electrode catalyst layers bonded to both surfaces of the solid polymer electrolyte membrane are also provided. And a solid polymer electrolyte membrane and / or electrocatalyst layer containing the polybenzazole compound having a sulfonic acid group and / or a phosphonic acid group of the present invention as a constituent component. A polymer electrolyte membrane / electrode catalyst layer composite can be obtained,
This solid polymer electrolyte membrane / electrode catalyst layer composite is excellent not only in processability, solvent resistance, durability, heat resistance, and mechanical properties, but also in ion conductivity, so it is a major member of fuel cells and the like. Can be preferably used as.

[Brief description of drawings]

FIG. 1 is an IR spectrum of a polybenzimidazole compound having a sulfonic acid group synthesized from TAS and STA.

FIG. 2 shows T of a film composed of a polybenzimidazole compound having a sulfonic acid group synthesized from TAS and STA.
GA chart

FIG. 3 is an IR spectrum of a polybenzimidazole compound having a sulfonic acid group synthesized with a composition of TAS and TPA / SIA = 66/34.

FIG. 4 is an IR spectrum of a polybenzimidazole compound having a phosphonate group synthesized from TAS and DCP.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shiro Hamamoto             2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo             Koki Co., Ltd. (72) Inventor Junko Nakao             2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo             Koki Co., Ltd. (72) Inventor Satoshi Takase             2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo             Koki Co., Ltd. F-term (reference) 4J043 PA02 PA04 PA08 PA09 PA10                       PC186 QB15 QB34 QB35                       QB41 RA42 RA52 RA57 SA06                       SA08 SA43 SA71 SA83 SB02                       TA12 TA75 TA79 TB02 UA121                       UA122 UA131 UA132 UA141                       UA262 UB011 UB061 UB121                       UB151 UB282 UB301 UB401                       UB402 VA011 VA012 VA021                       VA022 VA042 VA051 VA052                       VA061 VA081 VA082 XA11                       XB37 YA06 ZA11 ZA12 ZA31                       ZA41 ZA44 ZB11 ZB14 ZB47                 5H026 AA06 CX05 EE18 HH05 HH06                       HH08    (54) [Title of the Invention] Polybenzazole compound having sulfonic acid group and / or phosphonic acid group, resin containing the same                     Composition, resin molded product, solid polymer electrolyte membrane, solid electrolyte membrane / electrode catalyst layer composite and composite thereof                     Manufacturing method

Claims (16)

[Claims] 1. A polybenzazole comprising a 2,2′-disulfo-4,4′-biphenyldicarboxylic acid binding unit or a 3,3′-disulfo-4,4′-biphenyldicarboxylic acid binding unit. Compounds. 2. A polybenzazole-based compound comprising a binding unit represented by the following formula (1) and / or formula (2). [Chemical 1] (In the formulas (1) and (2), m ¹ is from 1 to 4
Represents an integer of, Ar represents an aromatic bond unit,
X ¹ is —SO ₂ — and Y ¹ represents an S atom or an O atom. ) 3. A resin composition containing the polybenzazole compound according to claim 1 as a main constituent component. 4. A resin molded product comprising the polybenzazole compound according to any one of claims 1 to 3 as a main constituent component. 5. A solid polymer electrolyte membrane comprising the polybenzazole compound according to any one of claims 1 to 3 as a main constituent component. 6. A composite comprising a solid polymer electrolyte membrane and an electrode catalyst layer bonded to both surfaces of the solid polymer electrolyte membrane as constituent elements, the solid polymer electrolyte membrane and / or
Alternatively, a solid polymer electrolyte membrane / electrode catalyst layer composite comprising the polybenzazole compound according to claim 1 as a component constituting the electrode catalyst layer. 7. A composite comprising a solid polymer electrolyte membrane and an electrode catalyst layer bonded to both surfaces of the solid polymer electrolyte membrane as constituent elements, the solid polymer electrolyte membrane and / or
Alternatively, as a component constituting the electrode catalyst layer, a binding unit represented by the following formulas (3) and (4) is n ¹ :
A solid polymer electrolyte membrane / electrode catalyst layer composite comprising a polybenzazole-based compound which is contained as a constituent element in a molar ratio of (1-n ¹ ). [Chemical 2] (In the formulas (3) and (4), m ² is from 1 to 4
Represents an integer of, Ar represents an aromatic bond unit,
X ² is _{-O -, - SO 2 -,} - C (CH 3) 2 -, - C (C
F _{3) 2} -, - OPhO- is from the group consisting one or more selected, Ph denote the divalent aromatic bond unit. Further, the molar ratio satisfies the formula of 0.2 ≦ n ¹ ≦ 1.0. ) 8. A solid polymer electrolyte membrane and the solid polymer electrolyte membrane
With the electrocatalyst layer bonded on both sides of the degrading membrane as a component
A solid polymer electrolyte membrane and / or
Alternatively, as a component constituting the electrode catalyst layer, the following formula
Contain a binding unit selected from (5) to (8)
And a polybenzazole-based compound containing
A solid polymer electrolyte membrane / electrode catalyst layer composite. [Chemical 3] (In formulas (5) to (8), m³Is an integer from 1 to 4
Represents the number, Ar represents an aromatic bond unit, X³
Is -O-, -SO₂-, -S-, -CO-, -CH ₂-,
-OPhO- is one or more selected from the group consisting of:
Y²Is an NH group, an S atom, or an O atom, and Z is an S atom.
Is a child or O atom, and Ph is a divalent aromatic bond unit.
And R represents an H atom or a methyl group.
To do. ) 9. The logarithmic viscosity of the polybenzazole-based compound, which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer, measured in concentrated sulfuric acid is 0.25 to 10 dl / g.
The solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of claims 6 to 8, which satisfies the condition of being in the range. 10. A voltage of 10,000 Hz is applied under conditions of 80 ° C. and 95% RH of a sulfonic acid group-containing polybenzazole compound which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer. The conductivity obtained by measuring the alternating current impedance is 0.0
The solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of claims 6, 7, and 9, which satisfies the condition of being in the range of 1 to 1.0 S / cm. 11. A voltage of 10,000 Hz is applied under conditions of 80 ° C. and 95% RH of a phosphonic acid group-containing polybenzazole compound, which is a constituent component of a solid polymer electrolyte membrane and / or an electrode catalyst layer. The conductivity obtained by measuring the alternating current impedance is 0.0
The solid polymer electrolyte membrane / electrode catalyst layer composite according to claim 8 or 9, which satisfies the condition of being in the range of 01 to 1.0 S / cm. 12. The solubility of the polybenzazole-based compound, which is a constituent component of the solid polymer electrolyte membrane and / or the electrode catalyst layer, in N-methylpyrrolidone at 170 ° C. is 5% (w / w) or more. The solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of claims 6 to 11, which satisfies certain conditions. 13. A polybenzazole compound, which is a constituent of a solid polymer electrolyte membrane and / or an electrode catalyst layer, has a sulfonic acid group of 1.5 meq / g or more in a molecule and / or
Alternatively, it has a phosphonic acid group and satisfies the condition that the mass reduction upon immersion in water at 25 ° C. for 72 hours is in the range of 0 to 5% (w / w). A solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of the claims. 14. A polybenzazole-based compound having a sulfonic acid group, which is a constituent component of a solid polymer electrolyte membrane and / or an electrode catalyst layer, is 200 ° C. in thermogravimetric measurement.
The condition that the 3% mass reduction temperature is in the range of 370 to 550 ° C. when the mass at the time of temperature rise is used as a reference, satisfies the condition described in any one of claims 6, 7, 9, 10, 12, and 13. A solid polymer electrolyte membrane / electrode catalyst layer composite as described. 15. When the polybenzazole-based compound having a phosphonic acid group, which is a constituent of the solid polymer electrolyte membrane and / or the electrode catalyst layer, is based on the mass at the time of heating at 200 ° C. in thermogravimetric measurement. 3% mass reduction temperature is 4
The solid polymer electrolyte membrane / electrode catalyst layer composite according to any one of claims 8, 9, 11, 12, and 13, which satisfies a condition of being in the range of 00 to 550 ° C. 16. A method for producing a composite, comprising a step of adhering a solid polymer electrolyte membrane and an electrode catalyst layer bonded to both surfaces of the solid polymer electrolyte membrane with a binder, wherein The molecular electrolyte membrane and / or the electrode catalyst layer contains the polybenzazole compound according to any one of claims 6 to 15 as a constituent component, and the binder also contains the polybenzazole according to any one of claims 6 to 15. A method for producing a composite of a solid polymer electrolyte membrane / electrode catalyst layer, which comprises a system compound as a constituent component.