JP2008291212A - Proton transporting material, ion exchanger using the same, membrane electrode assembly, fuel cell, sulfonic acid type liquid crystal polymer material, and material having phosphonic acid group - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proton transporting material having excellent proton transporting property by setting phase transition temperature at 200°C or below to make the sulfonic group hard to leave and setting to express a crystal phase at low temperature, and having an excellent mechanical property, especially suitable for electrolyte membrane of fuel cell, and to provide a use and raw material for producing the proton transporting material. <P>SOLUTION: The problem is solved by the proton transporting material obtained by mixing a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group as indispensable materials. The proton transporting material which has been prepared by adding and mixing a material having a mesogenic group and a phosphonic acid group with a specific molecular structure to a sulfonic acid type liquid crystal polymer material having a mesogenic group and a specific molecular structure, is preferred. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a proton transport material, an ion exchanger using the same, a membrane electrode assembly, a fuel cell, a sulfonic acid type liquid crystal polymer material, and a material having a phosphonic acid group, and more specifically, excellent mechanical properties. In addition, the proton transport material has excellent proton transport ability even under low humidification and excellent stability, and is used for an ion exchanger, a membrane electrode assembly (hereinafter sometimes referred to as MEA), and a fuel cell. The present invention relates to a proton transport material useful as a raw material for an electrolyte membrane, a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group, which are raw materials for such a proton transport material.

In recent years, fuel cells have attracted attention as an effective solution for environmental problems and energy problems. A fuel cell oxidizes a fuel such as hydrogen by using an oxidant such as oxygen and converts chemical energy associated therewith into electric energy.
Fuel cells are classified into alkali type, phosphoric acid type, solid polymer type, molten carbonate type, solid oxide type, etc., depending on the type of electrolyte. The polymer electrolyte fuel cell (PEFC) is operated at a low temperature, has a high output density, and can be reduced in size and weight. Therefore, it is expected to be applied as a portable power source, a household power source, and an in-vehicle power source. ing.

  When power is generated using a polymer electrolyte fuel cell, in order to improve the power generation performance, hydrogen humidified from the anode is supplied to the MEA and oxygen humidified from the cathode is supplied to the MEA. For this reason, the fuel cell system requires a humidifier, which increases the cost. Therefore, a fuel cell system that does not require a humidifier is required for cost reduction and compactness, and a low humidification or non-humidification type MEA is desired.

As an electrolyte membrane for a polymer electrolyte fuel cell (PEFC), a perfluorocarbon sulfonic acid membrane is widely used. However, since it contains fluorine, there is a problem that the environmental load at the time of disposal is high.
Therefore, a hydrocarbon film not containing fluorine (see Patent Document 1) has been developed. Since the sulfonic acid group in the hydrocarbon film not containing fluorine can dissociate hydrogen ions, it exhibits excellent proton conductivity.
However, in the case of the hydrocarbon film having no fluorine, since the sulfonic acid group (—SO ₃ H group) is present at random positions as shown in FIG. 6, proton conductivity is low under low humidification conditions. There is a problem that it tends to be low.

  In order to solve this problem, the use of a sulfonic acid type liquid crystal monomer material having a smectic phase has been studied. In the liquid crystal state of the sulfonic acid type liquid crystal monomer material, the ion conduction sites of the sulfonic acid group are overlapped in a dense state. It has also been found that the solid state maintaining the molecular arrangement of the liquid crystal state of the sulfonic acid type liquid crystal monomer material has excellent proton conductivity (see Patent Document 2). .

  However, this sulfonic acid type liquid crystal monomer material is an excellent material, but in order to use the sulfonic acid type liquid crystal monomer material as it is as an electrolyte membrane for a fuel cell, the sulfonic acid type liquid crystal monomer itself has no mechanical properties. Difficulties and problems are likely to occur in practical use.

By the way, if a solid state can be obtained while maintaining the molecular arrangement in the liquid crystal state, a solid film in the liquid crystal state can be obtained. Therefore, it is not necessary to add a material for holding the liquid crystal, and the usability is greatly improved.
At this time, it is necessary to temporarily change the molecular arrangement, which is disordered in the solid state, to a liquid crystal state and to arrange the disordered molecular arrangement. However, when the phase transition temperature is 200 ° C. or higher, the sulfonic acid group is removed. Release, causing molecular decomposition. In the worst case, decomposition occurs so that liquid crystallinity is not exhibited.

  Therefore, it is conceivable to polymerize the sulfonic acid type liquid crystal monomer material, but when polymerized, the phase transition temperature to become liquid crystal tends to become extremely high, and when the phase transition temperature becomes 200 ° C. or higher, as described above. In this case, the sulfonic acid group is eliminated and the molecule is decomposed. Therefore, even when polymerizing, the subject which makes this phase transition temperature low arises.

On the other hand, even if the phase transition temperature can be lowered and the elimination of the sulfonic acid group and the decomposition of the molecule can be suppressed, as shown in FIG. When a defective portion lacking a sulfonic acid group (—SO ₃ H group) is generated, proton conductivity may be lowered. For this reason, the subject which reduces a defect also arises.
JP 2006-179448 A JP 2003-55337 A

The first object of the present invention is to reduce or eliminate defects generated when the sulfonic acid type liquid crystal polymer material is returned from the liquid crystal state to the solid state, and to lower the phase transition temperature to 200 ° C. or lower so that the sulfone group is not eliminated. In addition, the liquid crystal phase is expressed at a low temperature, has excellent proton conductivity, and is excellent in mechanical properties. Therefore, the present invention is to provide a proton transport material particularly suitable for an electrolyte membrane for a fuel cell,
A second object of the present invention is to provide an ion exchanger, a membrane electrode assembly (MEA), and a fuel cell using the proton transport material,
The third object of the present invention is to provide a raw material that can be used as a raw material for producing the proton transport material.

In order to solve the above problems, the present inventors have made extensive studies and as a result, obtained the following knowledge.
That is, a sulfonic acid type liquid crystal monomer is polymerized to synthesize a sulfonic acid type liquid crystal polymer material having a specific molecular structure having a mesogenic group (a unit having high rigidity of a structure in which two or more rings such as aromatic rings are connected). By adding and mixing a material having a specific molecular structure having a phosphonic acid group together with a mesogenic group to the sulfonic acid type liquid crystal polymer material, both mesogenic groups are stacked, and a sulfonic acid group and a sulfonic acid group are interposed between both mesogenic groups. As a result, as shown in FIG. 1, the phosphonic acid group complements the defects generated when the liquid crystal state is returned to the solid state, and the material having the phosphonic acid group itself is also protonated. It has the ability to transport, so that proton conductivity is improved and the phase transition temperature is lowered to 200 ° C. or lower, and a liquid crystal phase can be developed at a low temperature. And, thereby forming the basis of the present invention.

  The proton transport material according to claim 1 of the present invention is characterized in that a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group are mixed as essential components.

  The proton transport material according to claim 2 of the present invention is characterized in that in the proton transport material according to claim 1, the sulfonic acid type liquid crystal polymer material is represented by the following general formula (1).

[In the general formula (1), R ₁ is a hydrogen atom or a methyl group, A is an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B is An alkylene group, Z represents a mesogenic group, n1 represents an integer of 2 or more, and n2 represents an integer of 1 or more. ]

  The proton transport material according to claim 3 of the present invention is the proton transport material according to claim 2, wherein Z is biphenyl in the general formula (1), and the sulfonic acid type liquid crystal polymer material is represented by the following general formula (2). ).

[In the general formula (2), R ₁ is a hydrogen atom or a methyl group, A is an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B is An alkylene group, Z represents a mesogenic group, n1 represents an integer of 2 or more, and n2 represents an integer of 1 or more. ]

The proton transport material according to claim 4 of the present invention is the proton transport material according to claim 2 or claim 3, wherein the sulfonic acid type liquid crystal polymer material is such that R ₁ in the general formula (1) is a methyl group, A is a sulfonic acid type liquid crystal polymer material in which A is represented by —CO—O (CH ₂ ) n 2 — and B is represented by — (CH ₂ ) n 3 —.
[In the general formula (1), n2 represents an integer of 1 or more, and n3 represents an integer of 3 or more. ]

The proton transporting material according to claim 5 of the present invention is the proton transporting material according to claim 4, wherein the sulfonic acid type liquid crystal polymer material is such that R ₁ in the general formula (1) is a methyl group, and n2 is 1 to 18. A sulfonic acid type liquid crystal polymer material in which n3 is represented by 3-10.

  The proton transport material according to claim 6 of the present invention is the proton transport material according to claim 5, wherein the sulfonic acid type liquid crystal polymer material is a sulfone represented by n2 in the general formula (1) of 7 to 18. It is characterized by being an acid type liquid crystal polymer material.

  The proton transport material according to claim 7 of the present invention is the proton transport material according to any one of claims 1 to 6, wherein the material having the phosphonic acid group is represented by the following general formula (3). It is characterized by being.

[In the general formula (3), A represents an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B represents an alkylene group, and Z represents a mesogenic group. , N2 represents an integer of 1 or more. ]

  The proton transport material according to claim 8 of the present invention is the proton transport material according to claim 7, wherein Z is biphenyl in the general formula (3), and the material having the phosphonic acid group is represented by the following general formula (4). ).

[In the general formula (4), A represents an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B represents an alkylene group, and n 2 represents 1 or more. Indicates an integer. ]

The proton transport material according to claim 9 of the present invention is the proton transport material according to claim 7 or claim 8, wherein the material having the phosphonic acid group is such that A in the general formula (4) is-(CH ₂ ) n4 -, B is - (CH ₂₎ n3 - characterized in that it is a material having a phosphonic acid group represented by.
[In the general formula (4), n3 and n4 each represent an integer of 1 or more. ]

  The proton transport material according to claim 10 of the present invention is the proton transport material according to claim 9, wherein the material having the phosphonic acid group is such that n4 is 1 to 17 and n3 is 3 to 3 in the general formula (4). It is a material having a phosphonic acid group represented by 10.

  The proton transport material according to an eleventh aspect of the present invention is the proton transport material according to any one of the first to tenth aspects, wherein 0.1 to 60 mass% with respect to the sulfonic acid type liquid crystal polymer material. The material having the phosphonic acid group is mixed.

  The proton transport material according to claim 12 of the present invention is the proton transport material according to any one of claims 2 to 11, wherein the sulfonic acid type liquid crystal polymer represented by the general formula (1); The molecular arrangement in a liquid crystal state of a mixture with a material having a phosphonic acid group represented by the general formula (3) is used in a liquid crystal state.

  The proton transport material according to claim 13 of the present invention is the proton transport material according to any one of claims 2 to 11, wherein the sulfonic acid type liquid crystal polymer material represented by the general formula (1) is used. The molecular arrangement in a liquid crystal state with a mixture of materials having a phosphonic acid group represented by the general formula (3) is used in a solid state.

  The proton transport material according to claim 14 of the present invention is the proton transport material according to claim 12 or 13, wherein the liquid crystal state is smectic.

  A fifteenth aspect of the present invention is an ion exchanger using the proton transport material according to any one of the first to fourteenth aspects.

  A sixteenth aspect of the present invention is a membrane electrode assembly (MEA) using the proton transport material according to any one of the first to fourteenth aspects.

  A seventeenth aspect of the present invention is a fuel cell using the proton transport material according to any one of the first to fourteenth aspects.

  An eighteenth aspect of the present invention is a sulfonic acid type liquid crystal polymer material represented by the following general formula (1).

[In the general formula (1), R ₁ is a hydrogen atom or a methyl group, A is an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B is An alkylene group, Z represents a mesogenic group, n1 represents an integer of 2 or more, and n2 represents an integer of 1 or more. ]

  According to a nineteenth aspect of the present invention, in the sulfonic acid type liquid crystal polymer material according to the eighteenth aspect, in the general formula (1), Z is biphenyl, and is represented by the following general formula (2). .

[In the general formula (2), R ₁ is a hydrogen atom or a methyl group, A is an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B is An alkylene group, Z represents a mesogenic group, n1 represents an integer of 2 or more, and n2 represents an integer of 1 or more. ]

According to a twentieth aspect of the present invention, in the sulfonic acid type liquid crystal polymer material according to the eighteenth or nineteenth aspect, R ₁ in the general formula (1) is a methyl group, and A is —CO—O (CH ₂ ) n 2. -, B is - (CH ₂₎ n3 - characterized by being represented by.
[In the general formula (1), n2 represents an integer of 1 or more, and n3 represents an integer of 3 or more. ]

According to a twenty-first aspect of the present invention, in the sulfonic acid type liquid crystal polymer material according to the twenty-first aspect, R ₁ in the general formula (1) is a methyl group, n2 is 1 to 18, and n3 is 3 to 10. It is characterized by that.

  According to a twenty-second aspect of the present invention, in the sulfonic acid type liquid crystal polymer material according to the twenty-first aspect, n2 in the general formula (1) is represented by 7-18.

  A twenty-third aspect of the present invention is a material having a phosphonic acid group represented by the following general formula (3).

[In the general formula (3), A represents an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B represents an alkylene group, and Z represents a mesogenic group. , N2 represents an integer of 1 or more. ]

  According to a twenty-fourth aspect of the present invention, in the material having a phosphonic acid group according to the twenty-third aspect, in the general formula (3), Z is biphenyl, and is represented by the following general formula (4). .

[In the general formula (4), A represents an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B represents an alkylene group, and n 2 represents 1 or more. Indicates an integer. ]

According to a twenty-fifth aspect of the present invention, in the material having a phosphonic acid group according to the twenty- _third or twenty-fourth aspect, A in the general formula (4) is — (CH ₂ ) n 4 — and B is — (CH ₂ ). It is represented by n3-.
[In the general formula (4), n3 and n4 each represent an integer of 1 or more. ]

  According to a twenty-sixth aspect of the present invention, in the material having a phosphonic acid group according to the twenty-fifth aspect, n4 in the general formula (4) is represented by 1 to 17, and n3 is represented by 3 to 10.

The proton transport material according to claim 1 of the present invention is characterized in that a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group are mixed as essential components,
By adding and mixing a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group to this sulfonic acid type liquid crystal polymer material, the phosphonic acid group complements the defects that occur when the liquid crystal state is returned to the solid state. Moreover, since the material having a phosphonic acid group itself also has a proton transporting ability, the proton conductivity is improved, the phase transition temperature is lowered to 200 ° C. or lower, and a liquid crystal phase can be developed at a low temperature. In addition to being able to avoid a decrease in proton conductivity, it is excellent in mechanical properties, so it can be used as an ion exchanger, and has a remarkable effect that it is particularly suitable for an electrolyte membrane for a fuel cell.

The proton transport material according to claim 2 of the present invention is characterized in that, in the proton transport material according to claim 1, the sulfonic acid type liquid crystal polymer material is represented by the general formula (1). ,
The sulfonic acid type liquid crystal monomer is polymerized to synthesize a sulfonic acid type liquid crystal polymer material having a specific molecular structure represented by the general formula (1) having a mesogenic group, and the sulfonic acid type liquid crystal polymer material is synthesized with phosphonic acid. By adding / mixing a material having a group, the phosphonic acid group supplements the defect that occurs when the liquid crystal state is returned to the solid state, and the material having the phosphonic acid group itself also has a proton transporting ability, so that proton conduction In addition to improving the properties, the phase transition temperature is lowered to 200 ° C. or lower, the liquid crystal phase can be developed at a low temperature, the decrease in proton conduction due to the elimination of the sulfonic acid group can be avoided, and the sulfonic acid type liquid crystal polymer material And a mixture of materials having a phosphonic acid group, since the sulfonic acid group and the phosphonic acid group are closely connected, the proton conductivity is low with low humidification, Expected to operate at low temperatures, such as in fuel cells, and is expected to reduce the cost of fuel cells, and by polymerizing sulfonic acid type liquid crystal monomers, sulfonic acid type liquid crystal polymer materials of high to ultra high molecular weight can be easily obtained. Therefore, it is excellent in mechanical characteristics and has a further remarkable effect that it can be used more suitably as an electrolyte membrane of a fuel cell.

  The proton transport material according to claim 3 of the present invention is the proton transport material according to claim 2, wherein Z is biphenyl in the general formula (1), and the sulfonic acid type liquid crystal polymer material is the general formula (2). ) And has a further remarkable effect that the liquid crystallinity is more easily exhibited.

The proton transport material according to claim 4 of the present invention is the proton transport material according to claim 2 or claim 3, wherein the sulfonic acid type liquid crystal polymer material is such that R ₁ in the general formula (1) is a methyl group, A is a sulfonic acid type liquid crystal polymer material in which A is represented by —CO—O (CH ₂ ) n 2 — and B is represented by — (CH ₂ ) n 3 —, and it is easier to exhibit liquid crystallinity. There is a further remarkable effect.

The proton transporting material according to claim 5 of the present invention is the proton transporting material according to claim 4, wherein the sulfonic acid type liquid crystal polymer material is such that R ₁ in the general formula (1) is a methyl group, and n2 is 1 to 18, characterized in that it is a sulfonic acid type liquid crystal polymer material in which n3 is represented by 3 to 10, and has a further remarkable effect that it is easy to show liquid crystallinity without excessively increasing hydrophobicity.

  The proton transport material according to claim 6 of the present invention is the proton transport material according to claim 5, wherein the sulfonic acid type liquid crystal polymer material is a sulfone represented by n2 in the general formula (1) of 7 to 18. It is characterized by being an acid-type liquid crystal polymer material, and has a further remarkable effect of exhibiting liquid crystal properties while having water resistance.

The proton transport material according to claim 7 of the present invention is the proton transport material according to any one of claims 1 to 6, wherein the material having the phosphonic acid group is represented by the general formula (3). It is characterized by being
The sulfonic acid type liquid crystal monomer is polymerized to synthesize a sulfonic acid type liquid crystal polymer material having a specific molecular structure represented by the general formula (1) having a mesogenic group, By adding and mixing a material having a specific molecular structure having a phosphonic acid group together with the mesogenic group represented by the formula (3), both mesogenic groups can easily be stacked to exhibit liquid crystallinity as shown in FIG. As a result, a sulfonic acid group and a phosphonic acid group are closely connected to each other between the mesogenic groups. As a result, the phosphonic acid group compensates for a defect that occurs when the liquid crystal state is returned to the solid state. Since the acid group-containing material itself also has proton transportability, the proton conductivity is improved and the phase transition temperature is lowered to 200 ° C. or lower, so that a liquid crystal phase can be developed at a low temperature. Both exhibits the additional remarkable effect that excellent mechanical properties, suitable for use as an electrolyte membrane of a fuel cell.

  The proton transport material according to claim 8 of the present invention is the proton transport material according to claim 7, wherein in the general formula (3), Z is biphenyl, and the material having a phosphonic acid group is the general formula (4). The material having a phosphonic acid group is added to and mixed with the sulfonic acid type liquid crystal polymer material having the specific molecular structure represented by the general formula (2). In addition, the liquid crystallinity can be further easily exhibited.

The proton transport material according to claim 9 of the present invention is the proton transport material according to claim 7 or claim 8, wherein the material having the phosphonic acid group is such that A in the general formula (4) is-(CH ₂ ) n4 -, B is - (CH ₂₎ n3 - in which is characterized in that the a material having a phosphonic acid group represented, sulfonic acid-type liquid crystal polymer material represented by the general formula (3) It is possible to further stack with the mesogenic group and to exhibit a liquid crystallinity, which is further remarkable.

  The proton transport material according to claim 10 of the present invention is the proton transport material according to claim 9, wherein the material having the phosphonic acid group is such that n4 is 1 to 17 and n3 is 3 to 3 in the general formula (4). It is characterized by being a material having a phosphonic acid group represented by 10 and exhibits a liquid crystal property by further stacking with a mesogenic group of the sulfonic acid type liquid crystal polymer material represented by the general formula (3). There is a further remarkable effect that it is easy.

  The proton transport material according to an eleventh aspect of the present invention is the proton transport material according to any one of the first to tenth aspects, wherein 0.1 to 60 mass% with respect to the sulfonic acid type liquid crystal polymer material. The phosphonic acid group-containing material is mixed, and it is easy to reliably exhibit liquid crystallinity, the proton conductivity is surely improved, and the phase transition temperature is lowered to 200 ° C. or lower. In addition, the liquid crystal phase can be exhibited, the mechanical properties are excellent, and it can be suitably used as an electrolyte membrane of a fuel cell.

  The proton transport material according to claim 12 of the present invention is the proton transport material according to any one of claims 2 to 11, wherein the sulfonic acid type liquid crystal polymer represented by the general formula (1); A liquid crystal state molecular arrangement of a mixture with a material having a phosphonic acid group represented by the general formula (3) is used in a liquid crystal state, for example, an electrolyte solution excellent in proton conductivity It can be used as a further remarkable effect.

The proton transport material according to claim 13 of the present invention is the proton transport material according to any one of claims 2 to 11, wherein the sulfonic acid type liquid crystal polymer material represented by the general formula (1) is used. The molecular arrangement in a liquid crystal state with a mixture of materials having a phosphonic acid group represented by the general formula (3) is used in a solid state,
Since it is a solid having a molecular arrangement in a liquid crystal state, it has a further remarkable effect that it is suitable for, for example, an electrolyte membrane for fuel cells having excellent mechanical properties and excellent proton transport ability.

  The proton transport material according to claim 14 of the present invention is characterized in that, in the proton transport material according to claim 12 or claim 13, the liquid crystal state is smectic, and more excellent mechanical properties and excellent In addition, it has a further remarkable effect that it is suitable for, for example, an electrolyte membrane for a fuel cell having a proton transporting ability.

A fifteenth aspect of the present invention is an ion exchanger using the proton transport material according to any one of the first to fourteenth aspects,
There is a remarkable effect that it can be used as an ion exchanger having excellent ion exchange characteristics.

  A sixteenth aspect of the present invention is a membrane electrode assembly (MEA) characterized by using the proton transport material according to any one of the first to fourteenth aspects, and has excellent mechanical properties. It has a high proton conductivity with low humidification, is expected to operate at a low temperature such as a fuel cell, and has the remarkable effect of reducing the cost of the fuel cell.

A seventeenth aspect of the present invention is a fuel cell using the proton transport material according to any one of the first to fourteenth aspects,
High power generation efficiency and low temperature operation are also expected, and the fuel cell cost can be reduced.

Claim 18 of the present invention is a sulfonic acid type liquid crystal polymer material represented by the general formula (1),
Sulfonic acid type liquid crystal monomers can be easily polymerized to synthesize sulfonic acid type liquid crystal polymers from high molecular weight to ultra high molecular weight, excellent in mechanical properties, capable of expressing liquid crystal phase, high proton conductivity, ion exchanger and There is a remarkable effect that it can be suitably used as an electrolyte membrane of a fuel cell.

  According to a nineteenth aspect of the present invention, in the sulfonic acid-type liquid crystal polymer material according to the eighteenth aspect, in the general formula (1), Z is biphenyl, and is represented by the general formula (2). It is easy to synthesize sulfonic acid type liquid crystal polymer from high molecular weight to ultra high molecular weight by polymerizing sulfonic acid type liquid crystal monomer, and has better mechanical properties, easier to show liquid crystallinity, and proton conductivity. It has a high remarkable effect that it can be suitably used as an ion exchanger or an electrolyte membrane of a fuel cell.

According to a twentieth aspect of the present invention, in the sulfonic acid type liquid crystal polymer material according to the eighteenth or nineteenth aspect, R ₁ in the general formula (1) is a methyl group, and A is —CO—O (CH ₂ ) n 2. -, B is represented by-(CH ₂ ) n 3-, and it is easy to show liquid crystallinity and has a further remarkable effect of further improving the heat resistance of the sulfonic acid group.

According to a twenty-first aspect of the present invention, in the sulfonic acid type liquid crystal polymer material according to the twenty-first aspect, R ₁ in the general formula (1) is a methyl group, n2 is 1 to 18, and n3 is 3 to 10. The liquid crystallinity is easily exhibited and the heat resistance of the sulfonic acid group is further improved.

  According to a twenty-second aspect of the present invention, in the sulfonic acid-type liquid crystal polymer material according to the twenty-first aspect, n2 in the general formula (1) is represented by 7 to 18, and water resistance is improved. In addition, the liquid crystallinity is easily exhibited and the heat resistance of the sulfonic acid group is further improved.

  Claim 23 of the present invention is a material having a phosphonic acid group, which is represented by the general formula (3), and has a high compensation function for the sulfonic acid type liquid crystal polymer. In addition, since the phosphonic acid group complements the defects generated when the liquid crystal state is returned to the solid state, and the material having the phosphonic acid group also has a proton transporting ability, the proton conductivity is improved and the phase transition temperature is 200. It has a remarkable effect that the liquid crystal phase can be developed at a low temperature and has excellent mechanical properties.

  According to a twenty-fourth aspect of the present invention, in the material having a phosphonic acid group according to the twenty-third aspect, in the general formula (3), Z is biphenyl, and is represented by the general formula (4). It is easy to show liquid crystallinity, and the mixture with the sulfonic acid type liquid crystal polymer has a further remarkable effect that the heat resistance of the sulfonic acid group is further improved.

According to a twenty-fifth aspect of the present invention, in the material having a phosphonic acid group according to the twenty- _third or twenty-fourth aspect, A in the general formula (4) is — (CH ₂ ) n 4 — and B is — (CH ₂ ). It is characterized by being represented by n @ 3-, and it is easy to show liquid crystallinity, and the mixture with the sulfonic acid type liquid crystal polymer has a further remarkable effect that the heat resistance of the sulfonic acid group is further improved. .

  A twenty-sixth aspect of the present invention is the material having a phosphonic acid group according to the twenty-fifth aspect, wherein n4 is represented by 1 to 17 and n3 is represented by 3 to 10 in the general formula (4). Thus, there is a further remarkable effect that it is easy to stack and liquid crystal properties are easily exhibited.

FIG. 1 is an explanatory view schematically illustrating the proton transport state of the proton transport material of the present invention having a liquid crystal state molecular arrangement.
As shown in FIG. 7, a conventional sulfonic acid type liquid crystal polymer obtained by polymerizing a sulfonic acid type liquid crystal monomer material has a defect portion lacking a sulfonic acid group (—SO ₃ H group), and proton conductivity. In contrast, the proton transport material of the present invention shown in FIG. 1 can be removed from the liquid crystal state by adding and mixing a material having a phosphonic acid group to the sulfonic acid type liquid crystal polymer material. Since the phosphonic acid group complements the defects generated when the solid state is returned to the solid state, such defects are eliminated, and protons can be easily conducted as shown in FIG. Moreover, since the material having a phosphonic acid group itself has a proton transporting capability, the proton conductivity is further improved, and the phase transition temperature is lowered to 200 ° C. or lower, and a liquid crystal phase can be developed at a low temperature. It is possible to obtain effects such as avoiding a decrease in proton conduction due to separation and excellent mechanical properties.

(Proton transport material)
The proton transport material of the present invention is a proton transport material in which a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group are mixed as essential components. Preferably, for example, the general formula (1) or the general formula ( It is a mixture containing a sulfonic acid type liquid crystal polymer material represented by 2) and a material having a phosphonic acid group represented by the general formula (3).
Such a mixture contains 0.1 to 60% by mass of the material having a phosphonic acid group represented by the general formula (3) with respect to the sulfonic acid type liquid crystal polymer material represented by the general formula (1). Preferably it contains 3-20 mass%.
If it is less than 0.1% by mass, the complementation effect of the material having a phosphonic acid group represented by the general formula (3) is low, and if it exceeds 60% by mass, liquid crystallinity may be hardly exhibited.

(Sulphonic acid type liquid crystal polymer material)
The sulfonic acid type liquid crystal polymer material represented by the general formula (1) may be a homopolymer obtained by homopolymerizing a sulfonic acid type liquid crystal monomer represented by the following general formula (5), or a co-polymer. The polymerization component may be a copolymer having a repeating unit derived by copolymerizing a copolymer component such as acrylic acid, methacrylic acid or styrene.
The repeating unit represented by the general formula (1) is preferably 50 mol% or more in the copolymer. Among them, 100 mol% of a homopolymer having no different components is particularly preferable because the ion conduction sites of the sulfonic acid group can be stacked in a dense state.
The molecular weight of the polymer is such that the number average molecular weight is in the range of 1000 to tens of millions, preferably in the range of tens of thousands to millions. If the number average molecular weight is less than 1000, mechanical properties cannot be obtained, and if it exceeds tens of millions, the production of the polymer becomes difficult and the yield may be deteriorated.
N1 in the general formula (1) is an integer of 2 or more, preferably 2 to tens of thousands, and more preferably 20 to 2000.

[In the general formula (5), R ₁ represents a hydrogen atom or a methyl group, A represents an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B represents an alkylene group. Group Z represents a mesogenic group, and n2 represents an integer of 1 or more. ]

A method for producing the sulfonic acid type liquid crystal polymer material used in the present invention will be described below.
For example, in order to produce a high molecular weight sulfonic acid type liquid crystal polymer material crosslinked with a homopolymer, a copolymer, or a crosslinking agent of the general formula (5) which is a sulfonic acid type liquid crystal monomer, a desired sulfone is used. In the presence of a polymerization initiator, an acid type liquid crystal monomer or a desired sulfonic acid type liquid crystal monomer and a copolymerization component or a crosslinking agent are used in a known polymerization method, for example, solution polymerization method, suspension polymerization method, emulsion polymerization method, bulk It can be produced by carrying out a polymerization reaction by a radical polymerization method such as a polymerization method, photopolymerization, thermal polymerization or gas phase polymerization method. Among them, the solution polymerization method can be preferably used because it is easy to operate.

Here, in the sulfonic acid type liquid crystal polymer material represented by the general formula (1), the mesogenic group Z includes the following. The mesogenic group Z is usually composed of 2 to 3 rings and a linking group.
Examples of the ring structure include a benzene ring, a biphenyl ring, a cyclohexane ring, a bicyclooctane ring, a pyridine ring, a pyridazine ring, a pyrimidine ring and a pyrazine ring, and a five-membered ring such as a furan ring.
On the other hand, the linking group contributes to linearity and polarizability such as triple bond and double bond, as well as ester bond, azo bond, oxyazo bond, azomethylene bond, dimethylene and oxymethylene, which have great influence on both shape and polarity. And so on. Moreover, as a kind of liquid crystal, a smectic liquid crystal in which liquid crystal molecules can be more densely formed is preferable.

  Among the sulfonic acid type liquid crystal polymer materials represented by the general formula (1), the sulfonic acid type liquid crystal polymer material having a biphenyl skeleton as represented by the general formula (2) is easy to have liquid crystallinity and particularly excellent. ing.

In the general formula (1) or the general formula (2), R ₁ is a hydrogen atom or a methyl group, A is an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or The group represented by -CO- is shown, and the alkylene group may be linear or branched.
Specifically, the alkylene group is preferably one having 1 to 18 carbon atoms, for example, methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, ethylethylene group, propylene group, butylene group, hexylene. Group, octadecylene group, nonylene group, decylene group, dodecylene group and the like. Among these, an alkylene group having 6 to 10 carbon atoms is more preferable.
In addition, n _{2 of} —CO—O (CH ₂ ) n 2 — is preferably 1 to 18, and n 2 of 7 to 18 is particularly preferable because it has water resistance and easily exhibits liquid crystallinity. The reason is that when n2 is less than 7, the water resistance is poor and the hydrophobicity exceeding 18 is enhanced.

B in the general formula (1) or the general formula (2) represents an alkylene group [— (CH ₂ ) n 3 —], which may be linear or branched.
Specifically, those having 1 to 18 carbon atoms are preferable, for example, methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, ethylethylene group, propylene group, butylene group, hexylene group, octadecylene group, nonylene. Group, decylene group, dodecylene group and the like. Among them, an alkylene group having 3 to 10 carbon atoms (n3) is preferable. This is because when the carbon number (n3) is less than 3, the water resistance is poor and liquid crystallinity is hardly exhibited, and when (n3) exceeds 10, the hydrophobicity increases. A and B may be the same alkylene group or different alkylene groups.

(Materials with phosphonic acid groups)
As the material having a phosphonic acid group used in the present invention, a material having a phosphonic acid group represented by the general formula (3) can be preferably used. In the general formula (3), as in the general formula (1), A is represented by an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—. The alkylene group may be either linear or branched. n2 represents an integer of 1 or more, preferably 1-17.
Examples of the alkylene group [— (CH ₂ ) n 4 —] include a hexylene group, an octadecylene group, a nonylene group, a decylene group, a dodecylene group, a tetradecylene group, and the like, and those having a carbon number (n4) of 1 to 17 preferable. This is because the biphenyl skeleton of the sulfonic acid type liquid crystal polymer and the biphenyl skeleton of the material having a phosphonic acid group are easily stacked, and the effect of lowering the liquid crystal phase temperature is increased.

In the general formula (3), as in the general formula (1), B represents an alkylene group [— (CH ₂ ) n 3 —], which may be linear or branched.
Specifically, those having 3 to 10 carbon atoms (n3) are preferable, for example, trimethylene group, tetramethylene group, pentamethylene group, ethylmethylene group, propylene group, butylene group, hexylene group, octadecylene group, nonylene group, decylene group. , Dodecylene group and the like. A and B may be the same alkylene group or different alkylene groups.

  A, Z and B in the general formula (1) may be the same as or different from A, Z and B in the general formula (3).

As the sulfonic acid-type liquid crystal polymer material, R ₁ is a methyl group in the general formula (1), A is _{-CO-O (CH 2) n2} -, B is - (CH ₂₎ n3 - expressed in, and , N2 is 7 to 18, n3 is 3 to 10 and a phosphonic acid type liquid crystal polymer material is used. As the material having the phosphonic acid group, A in the general formula (3) is-(CH ₂ ) n4-, B A proton transport material made of a mixture of phosphonic acid groups represented by — (CH ₂ ) n 3 — and a mixture of the two is more preferable.
This is because, while having water resistance, ion conduction sites such as a sulfonic acid group and a phosphonic acid group can be closely linked from a mesogenic group, and even if the amount of the material having the phosphonic acid group is increased. This is because liquid crystallinity is not lost and proton conductivity can be improved. In this case, the material having a phosphonic acid group is particularly preferably a liquid crystal material.

One example of the preparation of the proton transport material of the present invention will now be described.
For example, after dissolving both a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group in a solvent capable of dissolving, the solvent is stirred and mixed, and then spread on a substrate, for example, heated and decompressed to remove the solvent. Thus, a film or sheet-like product can be prepared.

Since the proton transport material of the present invention is excellent in proton transportability and has a high ion exchange capacity, it can be used as an electrolyte, an electrolyte membrane or an ion exchanger. Furthermore, it is also possible to produce a solid electrolyte membrane using the proton transport material of the present invention, and to produce a membrane electrode assembly (MEA) and a fuel cell using this.
The following method can be shown as an example of a method for producing MEA using the proton transport material of the present invention. First, the proton transport material of the present invention is laminated on a support and dried. Next, after adjusting the molecular arrangement in the liquid crystal state, the electrolyte layer is formed in the solid state while maintaining the molecular arrangement. At this time, if a molecular alignment film, rubbing, or the like is performed, the molecular arrangement may be more orderly arranged, and proton conductivity may be improved.
If necessary, a protective film may be laminated and stored on the electrolyte layer. In use, after the support and the protective film are peeled off, an electrode layer containing a gas diffusion layer and a catalyst layer is formed on both sides of the electrolyte layer, thereby obtaining an MEA. A fuel cell can be manufactured by assembling a separator or an auxiliary device (a gas supply device, a cooling device, or the like), and singly or stacking them.
Moreover, the suitable thickness of the electrolyte layer formed of the proton transport material in the present invention is usually about 0.1 to 500 μm, more preferably 10 μm to 150 μm. This is because if the formed resistance element is too thick, the resistance value becomes large, and if it is too thin, the mechanical properties of the electrolyte layer are deteriorated.

FIG. 8 is a cross-sectional explanatory view of one embodiment of the membrane electrode assembly of the present invention.
The membrane electrode assembly 12 is formed by joining and laminating the electrode catalyst layers 2 and 3 on both surfaces of the electrolyte membrane 1 by a conventional method.

  FIG. 9 is an exploded cross-sectional view showing the configuration of an embodiment of a single cell of a polymer electrolyte fuel cell equipped with the membrane electrode assembly 12. The air electrode side gas diffusion layer 4 having a structure in which a mixture of carbon black and polytetrafluoroethylene (PTFE) is applied to carbon paper, facing the electrode catalyst layer 2 and the electrode catalyst layer 3 of the membrane electrode assembly 12, and The fuel electrode side gas diffusion layer 5 is disposed. Thereby, the air electrode 6 and the fuel electrode 7 are comprised, respectively. A set of conductive and gas-impermeable materials having a gas flow path 8 for reaction gas flow facing a single cell and a cooling water flow path 9 for cooling water flow on the opposing main surface. A single cell 11 is formed by being sandwiched by the separator 10. A fuel cell can be manufactured by stacking the single cells 11 or the single cells 11.

  The proton transport material of the present invention can be used in liquid form or as a film. A support can be used when used as a film. For example, a film made of polyimide, polyethylene terephthalate, polypropylene, polyethylene, polyethersulfone, polycarbonate, cycloolefin, norbornene, aluminum pet, aluminum foil, or the like is used. These may be subjected to surface processing, or several kinds of films may be laminated. A liquid proton transport material is uniformly applied to a support, dried with hot air, and then the solvent is removed to form an electrolyte layer. Although it can be used as it is, it is usually preserved by laminating a protective film on the electrolyte layer and winding it in a roll, for example, in order to protect the electrolyte layer.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
<Synthesis of Sulfonated Liquid Crystal Polymer Material Represented by General Formula (1)>
5 ml of a dimethylformamide (DMF) solvent is added to a 50 ml eggplant type flask, and a sulfonated liquid crystal monomer represented by the general formula (5) [R ₁ in the general formula (5) is a methyl group, A is —CO—O (CH ₂ ) ₆ —, B is — (CH ₂ ) ₃ —, sulfonated liquid crystal monomer having a molecular weight of 476] and 7 mg of azobisisobutyl nitrile (AIBN) are added, nitrogen substitution is performed, and the pressure is reduced. I made it. Thereafter, the mixture was stirred and reacted at about 60 ° C. for 96 hours in an oil bath.
After the reaction, the mixture was poured into 100 ml of acetone, and the precipitate was filtered to obtain the desired product (yield: 72.0%).

<GPC measurement of sulfonic acid type liquid crystal polymer material obtained by thermal polymerization>
(1) Preparation of sample A 0.5% by mass sulfonic acid type liquid crystal polymer solution (solvent: DMF) is prepared and filtered through a membrane filter (pore size: 0.2 μm). Next, 20 μl of the filtrate is injected into the GPC.
(2) Analysis condition column: SHIMAZU GPC-P (guard column), GPC-80MD (8 mm × 300 mm)
Mobile phase: Dimethylformamide (DMF)
Flow rate: 1.0 ml / min
Detector: Alliance GPC2695 / 2414 (RI) manufactured by Water

(3) Analysis results The results analyzed under the above analysis conditions are shown in FIG. 2 [vertical axis: signal intensity, horizontal axis: retention time (min)].
FIG. 2 is a chromatograph in which a sulfonic acid type liquid crystal polymer material is detected by a differential refractive index detector. It was confirmed that a polymer having a high molecular weight of about 16.1 million was obtained by thermal polymerization at 60 ° C. for 96 hours. This is thought to be due to efficient polymerization using liquid crystal monomers.

<Thermal analysis of sulfonic acid type liquid crystal monomer material and sulfonic acid type liquid crystal polymer material obtained by thermal polymerization>
(1) Thermal analysis condition sample: about 5 mg
Thermal analyzer: EXSTAR6000 Tg / DTA6200 (made by SII Nanotechnology)
Nitrogen flow rate: 200 ml / min
[Tg: Thermogravimetry, Thermo-Gravimetry], [Differential Thermogravimetry: DTA: Differential Thermal Analysis], [Differential Thermogravimetry: DTg: Differential Thermo-Gravimetry]
(2) DTG of sulfonic acid type liquid crystal monomer material and sulfonic acid type liquid crystal polymer material
The results analyzed under the above conditions are shown in FIG. 3 [vertical axis: value obtained by differentiating weight change per unit time (μg / min), horizontal axis: sample temperature (° C.)].
In the sulfonic acid type liquid crystal monomer material, a rise estimated to be the elimination of the sulfonic acid group is observed from around 150 ° C., and in the sulfonic acid type liquid crystal polymer material, the rise is assumed to be the elimination of the sulfonic acid group from around 200 ° C. Observed and confirmed a peak.
It can be seen that by increasing the molecular weight of the sulfonic acid type liquid crystal monomer, the heat resistance is improved and the sulfonic acid group is hardly eliminated.

<Preparation of proton transport material of the present invention by mixing sulfonic acid type liquid crystal polymer material and material having phosphonic acid group>
In the general formula (4), 10% by mass of the sulfonic acid type liquid crystal polymer material, A in the formula (4) has a phosphonic acid group represented by — (CH ₂ ) _n4 —, and B represents — (CH ₂ ) _n3 —. A material (n4 = 9, n3 = 3) was used, dissolved in a solvent (DMF) capable of dissolving both, stirred and mixed, and then heated and decompressed to prepare a proton transport material composed of the mixture.
Next, the phase transition of the sulfonic acid type liquid crystal monomer material (A _M ), the obtained sulfonic acid type liquid crystal polymer material (A _P ), and the proton transport material (A _P + B) of the present invention to a liquid crystal phase The temperature (° C.) was measured by the following method.
The measurement results are shown in FIG.
A _M : sulfonic acid type liquid crystal monomer material A _P : sulfonic acid type liquid crystal polymer material B: material having phosphonic acid group A _P + B: proton transport material of the present invention

(Phase transition temperature measurement method)
Apparatus 1. Polarization microscope: Olympus BX51
2. Hot stage: LK-600FTIR manufactured by Japan High-Tech Co., Ltd.
3. Preparation: MATSUAMI MICRO COVER GLASS
Measurement procedure Place the sample between two slides.
2. Set one preparation on the hot stage.
3. Set the polarizing microscope to crossed Nicols (Two polarizing plates are orthogonal to prevent light from passing through).
4). Hot stage at 5 ° C./min. Raise the temperature.
5. Although the sample is dark in the solid state, when the liquid crystal transition temperature is reached, the fluidity appears and the dark image becomes brighter. This is the phase transition temperature.
6). When the temperature is further raised and the liquid state is uniformly melted, it becomes dark.

From the results shown in FIG. 4, when the sulfonic acid type liquid crystal monomer is polymerized by thermal polymerization, the phase transition temperature to the liquid crystal is 100 ° C. or lower for the sulfonic acid type liquid crystal monomer (A _M ). In the case of the sulfonic acid type liquid crystal polymer material (AP), it was found that the temperature rose to 300 ° C. or higher. Since the temperature at which the sulfonic acid group is eliminated is 100 ° C., in the case of the sulfonic acid type liquid crystal polymer material (A _P ), the sulfonic acid group is eliminated before the molecules are aligned in the liquid crystal, resulting in insufficient heat resistance. I found out that
However, from the results shown in FIG. 4, the proton transport material (Ap + B) of the present invention in which the material (B) having a phosphonic acid group is added to the sulfonated liquid crystal polymer material (A _P ) greatly decreases the liquid crystal phase temperature. It was found that a liquid crystal phase was developed around 100 ° C. at which the sulfonic acid group was not eliminated.

  On the other hand, it was confirmed that the proton transport material of the present invention shows smectic liquid crystal from the X-ray diffraction in the liquid crystal state shown in FIG. 10 and the texture obtained from the polarization microscope shown in FIG.

(X-ray diffraction measurement method in liquid crystal state)
The X-ray diffraction measurement result in the liquid crystal state of the proton transport material of the present invention is shown in FIG. 10 [Vertical axis: cps, Horizontal axis: 2θ / deg. ].

The proton transport ability was evaluated by the following measurement method.
Equipment NF ELECTRONIC INSTRUMENTS Frequency Response Analyzer 50580
1. Dissolve the sample in DMF solvent at 80 ° C.
2. Concentrate the solution.
3. The concentrated liquid is poured onto glass and dried to form a film.
Four platinum wires arranged at intervals of 4.5 mm and this film are bonded together and measured.
The resistance value was read from the obtained Cole-Cole plot, and the proton conductivity was calculated. The measurement was performed under the condition of not humidifying at room temperature.
The obtained results are shown in Table 1.

In Table 1, _Ap represents a sulfonic acid type liquid crystal polymer material, and B represents a material having a phosphonic acid group.
From Table 1, it was confirmed that by adding the material B having a phosphonic acid group to the sulfonic acid type liquid crystal polymer material A _P , the proton transport material (A _P + B) of the present invention also improves the proton conductivity. This is presumably because the material (B) having phosphonic acid filled in the defects as shown in FIG.

<Water resistance evaluation of sulfonic acid type liquid crystal polymer material>
In the general formula (2), R ₁ is a methyl group, A is —CO—O (CH ₂ ) ₆ — (n 2 = 6), and B is — (CH ₂ ) ₃ — (sample) In 1) and the general formula (2), R ₁ is a methyl group, A is —CO—O (CH ₂ ) ₁₀ — (n 2 = 10), and B is — (CH ₂ ) ₃ —. A material (sample 2) was synthesized, and water resistance at room temperature and 80 ° C. was evaluated by the following method.
The obtained samples 1 and 2 were immersed in a sufficient amount of pure water at room temperature to evaluate the water resistance. As a result, n2 = 6 sample 1 sulfonic acid type liquid crystal polymer material and n2 = 10 sample 2 Both of the sulfonic acid type liquid crystal polymer materials were confirmed to exhibit a certain level of water resistance. Further, the sulfonic acid type liquid crystal polymer material of Sample 2 with n2 = 10 does not dissolve at all even when immersed in a sufficient amount of pure water at room temperature and 80 ° C. for 30 minutes, and has very high water resistance. It was confirmed that It was confirmed that the sulfonic acid type liquid crystal polymer material of Sample 2 with n2 = 10 exhibits higher water resistance than the sulfonic acid type liquid crystal polymer material of Sample 1 with n2 = 6.

The proton transport material of the present invention is characterized in that a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group are mixed as essential components,
By adding and mixing a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group to this sulfonic acid type liquid crystal polymer material, the phosphonic acid group complements the defects that occur when the liquid crystal state is returned to the solid state. Moreover, since the material having a phosphonic acid group itself also has a proton transporting ability, the proton conductivity is improved, the phase transition temperature is lowered to 200 ° C. or lower, and a liquid crystal phase can be developed at a low temperature. In addition to being able to avoid a decrease in proton conductivity, it can be used as an ion exchanger because of its excellent mechanical properties, and is particularly suitable for an electrolyte membrane for fuel cells. High value.

It is explanatory drawing which illustrates typically the state of the proton transport of the proton transport material of this invention which has the molecular arrangement | sequence of a liquid crystal state. It is a graph which shows the GPC measurement result of the proton transport material of this invention. It is a graph which shows the DTG measurement result of a sulfonic acid type liquid crystal monomer material and a sulfonic acid type liquid crystal polymer material. It is explanatory drawing explaining the measurement result of the phase transition temperature of a sulfonic acid type liquid crystal monomer material, a sulfonic acid type liquid crystal polymer material, and the proton transport material of this invention. It is a polarization micrograph which shows that the proton transport material of this invention shows a smectic liquid crystal. It is explanatory drawing which illustrates typically the state of the proton transport of the hydrocarbon film | membrane which does not have a conventional fluorine. It is explanatory drawing which illustrates typically the state of the proton transport of the material which consists only of sulfonic acid type liquid crystal polymer materials. It is sectional explanatory drawing of one embodiment of the membrane electrode assembly which formed the electrode catalyst layer on both surfaces of the electrolyte membrane. FIG. 9 is an exploded cross-sectional view showing the configuration of a single cell of a polymer electrolyte fuel cell equipped with the membrane electrode assembly shown in FIG. 8. It is an X-ray diffraction pattern in the liquid crystal state of the proton transport material of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolyte membrane 2, 3 Electrode catalyst layer 4 Air electrode side gas diffusion layer 5 Fuel electrode side gas diffusion layer 6 Air electrode 7 Fuel electrode 8 Gas flow path 9 Cooling water flow path 10 Separator 11 Single cell 12 Membrane electrode assembly

Claims (26)

  A proton transport material comprising a sulfonic acid type liquid crystal polymer material and a material having a phosphonic acid group mixed as essential components. The proton transport material according to claim 1, wherein the sulfonic acid type liquid crystal polymer material is represented by the following general formula (1).
[In the general formula (1), R ₁ is a hydrogen atom or a methyl group, A is an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B is An alkylene group, Z represents a mesogenic group, n1 represents an integer of 2 or more, and n2 represents an integer of 1 or more. ] The proton transport material according to claim 2, wherein, in the general formula (1), Z is biphenyl, and the sulfonic acid type liquid crystal polymer material is represented by the following general formula (2).
[In the general formula (2), R ₁ is a hydrogen atom or a methyl group, A is an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B is An alkylene group, Z represents a mesogenic group, n1 represents an integer of 2 or more, and n2 represents an integer of 1 or more. ] The sulfonic acid-type liquid crystal polymer material, R ₁ is a methyl group in the general formula (1), A is _{-CO-O (CH 2) n2} -, B is - (CH ₂₎ n3 - sulfonic represented 4. The proton transport material according to claim 2, wherein the proton transport material is an acid type liquid crystal polymer material.
[In the general formula (1), n2 represents an integer of 1 or more, and n3 represents an integer of 3 or more. ] The sulfonic acid type liquid crystal polymer material is a sulfonic acid type liquid crystal polymer material in which R ₁ in the general formula (1) is a methyl group, n 2 is 1 to 18, and n 3 is 3 to 10. The proton transport material according to claim 4.   6. The proton transport material according to claim 5, wherein the sulfonic acid type liquid crystal polymer material is a sulfonic acid type liquid crystal polymer material in which n2 in the general formula (1) is represented by 7-18. The proton transport material according to any one of claims 1 to 6, wherein the material having the phosphonic acid group is represented by the following general formula (3).
[In the general formula (3), A represents an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B represents an alkylene group, and Z represents a mesogenic group. , N2 represents an integer of 1 or more. ] The proton transport material according to claim 7, wherein, in the general formula (3), Z is biphenyl, and the material having the phosphonic acid group is represented by the following general formula (4).
[In the general formula (4), A represents an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B represents an alkylene group, and n 2 represents 1 or more. Indicates an integer. ] It is a material having a phosphonic acid group represented by - material having a phosphonic acid group, the general formula (4) A in the _{- (CH 2) n4 -,} B is - (CH ₂₎ n3 The proton transport material according to claim 7 or claim 8, wherein
[In the general formula (4), n3 and n4 each represent an integer of 1 or more. ]   The material having a phosphonic acid group is a material having a phosphonic acid group in which n4 is 1 to 17 and n3 is 3 to 10 in the general formula (4). Proton transport material.   The proton transport according to any one of claims 1 to 10, wherein a material having 0.1 to 60% by mass of the phosphonic acid group is mixed with the sulfonic acid type liquid crystal polymer material. material.   Utilizing the molecular arrangement of the liquid crystal state of a mixture of the sulfonic acid type liquid crystal polymer represented by the general formula (1) and the material having a phosphonic acid group represented by the general formula (3) in the liquid crystal state. The proton transport material according to any one of claims 2 to 11, wherein:   The molecular arrangement of the liquid crystal state of the sulfonic acid type liquid crystal polymer material represented by the general formula (1) and the mixture of the material having a phosphonic acid group represented by the general formula (3) is used in a solid state. The proton transport material according to any one of claims 2 to 11, wherein the material is a proton transport material.   The proton transport material according to claim 12 or 13, wherein the liquid crystal state is smectic.   An ion exchanger using the proton transport material according to any one of claims 1 to 14.   A membrane electrode assembly (MEA), wherein the proton transport material according to any one of claims 1 to 14 is used.   A fuel cell using the proton transport material according to any one of claims 1 to 14. A sulfonic acid type liquid crystal polymer material represented by the following general formula (1):
[In the general formula (1), R ₁ is a hydrogen atom or a methyl group, A is an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B is An alkylene group, Z represents a mesogenic group, n1 represents an integer of 2 or more, and n2 represents an integer of 1 or more. ] In the said General formula (1), Z is biphenyl and is represented by following General formula (2), The sulfonic-acid type liquid crystal polymer material of Claim 18 characterized by the above-mentioned.
[In the general formula (2), R ₁ is a hydrogen atom or a methyl group, A is an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B is An alkylene group, Z represents a mesogenic group, n1 represents an integer of 2 or more, and n2 represents an integer of 1 or more. ] R ₁ is a methyl group in the general formula (1), A is _{-CO-O (CH 2) n2} -, B is - (CH ₂₎ n3- characterized by being represented by claim 18 or claim Item 20. A sulfonic acid type liquid crystal polymer material according to Item 19.
[In the general formula (1), n2 represents an integer of 1 or more, and n3 represents an integer of 3 or more. ] R ₁ is a methyl group in the general formula (1), n2 is 1-18, sulfonic acid-type liquid crystal polymer material according to claim 20, wherein the n3 is represented by 3 to 10.   The sulfonic acid type liquid crystal polymer material according to claim 21, wherein n2 in the general formula (1) is represented by 7-18. A material having a phosphonic acid group represented by the following general formula (3):
[In the general formula (3), A represents an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B represents an alkylene group, and Z represents a mesogenic group. , N2 represents an integer of 1 or more. ] 24. The material having a phosphonic acid group according to claim 23, wherein, in the general formula (3), Z is biphenyl and is represented by the following general formula (4).
[In the general formula (4), A represents an alkylene group, —C ₆ H ₄ —CH ₂ —, —CO—O (CH ₂ ) n 2 — or —CO—, B represents an alkylene group, and n 2 represents 1 or more. Indicates an integer. ] Formula (4) A in the _{- (CH 2) n4 -,} B is - has represented by that in which said claim 23 or claim 24 phosphonic acid groups described - (CH ₂₎ n3 material.
[In the general formula (4), n3 and n4 each represent an integer of 1 or more. ]   26. The material having a phosphonic acid group according to claim 25, wherein n4 in the general formula (4) is 1 to 17 and n3 is 3 to 10.