JP6826305B2 - Method for manufacturing polymer electrolyte membrane - Google Patents

Description

The present invention relates to a polymer electrolyte membrane and a manufacturing method thereof, for use in the electrochemical hydrogen pump.

In recent years, hydrogen energy has been attracting attention as a means of storing and transporting energy in the next generation. By using hydrogen as a fuel for fuel cells, it can be converted into electric power with theoretically higher energy efficiency than power generation using a heat engine, and since it is free of harmful emissions, it becomes a highly efficient clean energy source. obtain. Hydrogen is secondary energy, and there are various production methods, but if water is electrolyzed using surplus electricity from renewable energy, electricity can be converted to hydrogen energy without emitting carbon dioxide. .. Hydrogen production methods by electrolysis of water include alkaline water electrolysis and solid polymer electrolyte membrane (PEM) type water electrolysis, but PEM type water electrolysis can be operated at high current density and outputs renewable energy. It has the feature of being able to flexibly respond to fluctuations.

Depending on the storage method, hydrogen can be transported by tank lorry or tanker, so it can be supplied to areas with high demand when needed, which is a great advantage over power storage.

Examples of hydrogen storage methods include compressed hydrogen, liquid hydrogen, and hydrogen storage in alloys. In particular, the demand for compressed hydrogen is increasing in terms of its ready-to-use gas fuel and energy efficiency.

Conventionally, a positive displacement compressor has been used as a method for producing compressed hydrogen, but in recent years, an electrochemical hydrogen pump has been attracting attention. The electrochemical hydrogen pump is a hydrogen compressor that electrochemically compresses hydrogen by passing an electric current through a solid polymer type electrolyte membrane. Compared to positive displacement compressors, it has the features of high energy efficiency, quietness, compactness, and hydrogen purification.

The principle of the electrochemical hydrogen pump is shown below.
1. 1. Hydrogen supplied to the anode is oxidized by applying a voltage to generate protons and electrons.
2. 2. Protons are conducted to the cathode via ion exchange groups in the electrolyte membrane.
3. 3. Electrons are conducted from the anode to the cathode through an external circuit by applying a voltage.
4. Protons and electrons combine at the cathode to generate hydrogen again, compressing hydrogen at the cathode side.

Such, as an electrolyte membrane used in the electrochemical hydrogen pump, non-patent Documents 1, 2 and 3, Patent Documents 1, 2, 3 and 4, DuPont Co. of "Nafion (registered trademark)" Examples of its use have been reported.

"Journal of Power Source" (Journal of Power Source), 105 (2002) 208-215 "ECS Transactions" (ECS Transactions) 58 (1) 681-691 (2013) "Journal of the Electrochemical Society" (Journal of The Electrochemical Society) 149 (8) A1069-A1078 (2002)

International Publication 2003/021006 Pamphlet International Publication No. 2005/014468 Pamphlet Japanese Patent Application Laid-Open No. 11-131280 JP 2001-14089

However, since Nafion is an electrolyte membrane made of a perfluoropolymer that is essentially highly permeable to hydrogen, it does not have sufficient hydrogen barrier properties, and in an electrochemical hydrogen pump, compressed hydrogen is back-permeated from the cathode to the anode. there was a hydrogen Russia vinegar challenges by. Further, since the material has low breaking strength such as rubber, there is a problem that the film is deformed under high pressure. Further, when increasing the thickness in order to solve the problems, the hydrogen pressure Chijimiko rate due to the proton conductivity decreases there is a problem to decrease.

Thus, the polymer electrolyte material according to the prior art, in order to achieve a more efficient electrochemical hydrogen pump is economics, processability, proton conductivity, mechanical strength, chemical stability, physical durability It was inadequate in terms of sex.

In view of this background, the present invention has excellent hydrogen barrier properties, and also has excellent proton conductivity, excellent mechanical strength, physical durability and chemical stability under low and humid conditions. It is intended to provide a polymeric electrolyte membrane for an electrochemical hydrogen pump that can be achieved.

The present inventors, in order to solve the above problems, electrochemical hydrogen pump with a high hydrogen compression efficiency and result of repeating intensive study for electrolyte membrane Kiru de achieving long-term durability when the high hydrogen compression efficiency In terms of rate, it is necessary to have a film that is excellent in both high proton conductivity and hydrogen barrier properties, and in terms of long-term durability, it is particularly excellent in both tensile breaking strength and tensile breaking elongation. focusing on, a hydrocarbon electrolyte membrane satisfying them, even under high pressure, the film deformation and less loss due to hydrogen reverse osmosis, a high hydrogen compression efficiency, and long-term stable operation can excellent electrochemical hydrogen pump The present invention was completed by investigating that the present invention can be expressed and further various studies.

That is, the method for producing a polymer electrolyte membrane of the present invention is a method for producing a polymer electrolyte membrane, which comprises a step of casting and coating a polymer electrolyte membrane precursor solution on a substrate to form a polymer electrolyte membrane. hand,
The polymer electrolyte membrane
A polymer electrolyte membrane for an electrochemical hydrogen pump made of an ionic group-containing aromatic hydrocarbon polymer:
Proton conductivity per unit area at 80 ° C. and 25% relative humidity is 0.12 S / cm ² or more;
Proton conductivity of 8 S / cm ² or more per unit area in an atmosphere of 80 ° C. and 90% relative humidity;
Hydrogen permeability in an atmosphere of 80 ° C. and 90% relative humidity is 3.0 x ^10-7 cm ³ · (cm ² · s · cmHg) ^-1 or less;
The tensile breaking strength of a film having a width of 10 mm under an atmosphere of 25 ° C. and a relative humidity of 60% is 100,000 N or more;
Tensile breaking elongation is 150% or more;
, And the Ri thickness of Der more than 200μm below 30μm,
This is a method for producing a polymer electrolyte membrane for an electrochemical hydrogen pump, which comprises using a base material having a thickness satisfying the following (formula 1) as the base material .
7 ≦ T1 / T2 ≦ 15 (Equation 1)
(T1: Thickness of base material, T2: Thickness of polymer electrolyte membrane)

According to the present invention, it has excellent hydrogen barrier properties, and also achieves excellent proton conductivity, excellent mechanical strength, physical durability and chemical stability under low humidification conditions and humidification conditions. it is possible to provide an excellent electrochemical hydrogen pump for polymer electrolyte membrane utility that can.

Hereinafter, the polymer electrolyte membrane for an electrochemical hydrogen pump (hereinafter, may be simply referred to as “electrolyte membrane”) of the present invention will be described in detail.

<Polymer electrolyte membrane>
The electrolyte membrane of the present invention is made of an ionic group-containing aromatic hydrocarbon-based polymer. The ionic group-containing aromatic hydrocarbon-based polymer is a polymer having an aromatic ring in the main chain, and the aromatic ring includes not only a hydrocarbon-based aromatic ring but also a heterocycle. The use of aromatic hydrocarbon-based polymer, not the electrolyte membrane made of a conventional perfluoro-based polymers, that are both high tensile strength and low hydrogen permeability, obtain an electrolyte membrane suitable electrochemical hydrogen pump be able to.

Specific examples of ionic group-containing aromatic hydrocarbon-based polymers include polysulfone, polyether sulfone, polyphenylene oxide, polyarylene ether-based polymer, polyphenylene sulfide, polyphenylene sulfide sulfone, polyparaphenylene, polyarylene-based polymer, and polyarylene ketone. , Polyether ketone, polyarylene phosphinhoxide, polyether phosphinhoxide, polybenzoxazole, polybenzthiazole, polybenzimidazole, aromatic polyamide, polyimide, polyetherimide, polyimide sulfone and other polymers.

Among them, the aromatic polyether polymer is preferable as the ionic group-containing aromatic hydrocarbon polymer from the viewpoint of mechanical strength, physical durability, and manufacturing cost. Here, the aromatic polyether polymer is a general term for polymers having an aromatic ring and an ether bond in the main chain, and specific examples thereof include polyether sulfone, polyarylene ether polymer, polyether ketone, and poly. Examples include etherimide. Furthermore, it exhibits crystallinity due to the good packing of the main chain skeleton structure and extremely strong intermolecular cohesive force, has the property of not being completely soluble in general solvents, and is excellent in tensile strength and elongation, tear strength and fatigue resistance. Therefore, aromatic polyetherketone-based polymers are particularly preferable. Here, the aromatic polyetherketone-based polymer is a general term for polymers having at least an aromatic ring, an ether bond, and a ketone bond in the main chain, and is an aromatic polyetherketone, an aromatic polyetherketone ketone, and an aromatic. Includes group polyetheretherketone, aromatic polyetheretherketoneketone, aromatic polyetherketone etherketoneketone, aromatic polyetherketonesulfone, aromatic polyetherketone phosphine oxide, aromatic polyetherketonenitrile, and the like.

As the ionic group of the ionic group-containing aromatic hydrocarbon-based polymer, an atomic group having a negative charge is preferable, and one having a proton exchange ability is preferable. As such a functional group, a sulfonic acid group, a sulfonimide group, a sulfate group, a phosphonic acid group, a phosphoric acid group and a carboxylic acid group are preferable. The ionic group includes those which are salts. Such cation forming a salt, any metal cation, NR 4 + ^_(R is any organic group) can be mentioned as examples and the like. In the case of a metal cation, its valence is not particularly limited. Specific examples of preferable metal cations include cations such as Li, Na, K, Rh, Mg, Ca, Sr, Ti, Al, Fe, Pt, Rh, Ru, Ir and Pd. Of these, Na, K, and Li cations, which are inexpensive and can be easily proton-substituted, are preferably used. Among them, at least a sulfonic acid group, a sulfonimide group or a sulfate group is more preferable from the viewpoint of high proton conductivity, and a sulfonic acid group is most preferable from the viewpoint of raw material cost.

Examples of the method of introducing an ionic group into the polymer chain include a method of polymerizing using a monomer having an ionic group and a method of introducing an ionic group by a polymer reaction.

As a method of polymerizing using a monomer having an ionic group, a monomer having an ionic group in the repeating unit may be used. Such a method is described, for example, in the Journal of Membrane Science, 197, 2002, p. It is described in 231-242. This method is preferable because the ion exchange capacity of the polymer can be easily controlled.

Examples of the method for introducing an ionic group in a polymer reaction include Polymer Preprints (Japan), 51, 2002, p. It is possible by the method described in 750 and the like. Introduction of a phosphate group into a hydrocarbon-based polymer having an aromatic ring in the main chain is, for example, phosphorylation of a polymer having a hydroxyl group, and introduction of a carboxylic acid group is, for example, oxidizing a polymer having an alkyl group or a hydroxyalkyl group. By doing so, the introduction of sulfate groups is possible, for example, by sulfate esterification of polymers having hydroxyl groups. For the introduction of the sulfonic acid group into the aromatic hydrocarbon-based polymer, for example, the method described in JP-A-2-16126 or JP-A-2-208322 can be used. Specifically, for example, an aromatic hydrocarbon-based polymer is sulfonated by reacting it with a sulfonate such as chlorosulfonic acid in a solvent such as chloroform, or by reacting it with concentrated sulfuric acid or fuming sulfuric acid. be able to. The sulfonate agent is not particularly limited as long as it sulfonates a polymer, and sulfur trioxide or the like can be used in addition to the above. When the aromatic hydrocarbon-based polymer is sulfonated by this method, the degree of sulfonation can be controlled by the amount of the sulfonate agent used, the reaction temperature and the reaction time. The introduction of a sulfonimide group into a hydrocarbon polymer having an aromatic ring in the main chain is possible, for example, by reacting a sulfonic acid group with a sulfonamide group.

The molecular weight of the ionic group-containing aromatic hydrocarbon polymer thus obtained is preferably 10,000 to 5 million, more preferably 10,000 to 1 million, in terms of polystyrene-equivalent weight average molecular weight. preferable. If it is less than 10,000, any of mechanical strength, physical durability, and solvent resistance may be insufficient, such as cracks in the molded film. On the other hand, if it exceeds 5 million, the solubility may be insufficient, the solution viscosity may be high, and the processability may be poor.

The ionic group-containing aromatic hydrocarbon polymer used in the present invention does not contain the ionic group-containing segment (A1) and the ionic group from the viewpoint of proton conductivity and power generation characteristics under low humidification conditions. More preferably, it is a block polymer having a segment (A2). In this specification, for convenience, it is described as "segment (A2) containing no ionic group", but the segment (A2) contains ionic groups within a range that does not have a decisive adverse effect on the performance as an electrolyte membrane. It does not exclude that it is contained in a small amount.

The number average molecular weights of the ionic group-containing segment (A1) and the ionic group-free segment (A2) are related to the domain size of the phase-separated structure, and are of proton conductivity and physical durability under low humidification. From the balance, each is more preferably 5,000 or more, further preferably 10,000 or more, and most preferably 15,000 or more. Further, 50,000 or less is more preferable, more preferably 40,000 or less, and most preferably 30,000 or less.

As such a block polymer, the segment (A1) containing an ionic group is represented by the following general formula (S1), and the segment (A2) containing no ionic group is represented by the following general formula (S2). Is more preferable.

(In the general formula (S1), Ar ^{1 to} Ar ⁴ represent any divalent arylene group, and at least one of Ar ¹ and Ar ² has an ionic group as a substituent. Ar ³ and Ar ⁴ may or may not have an ionic group as a substituent. Ar ^{1 to} Ar ⁴ may be optionally substituted with a group other than the ionic group. Ar ^{1 to} Ar ⁴ are constituent units. Each may be the same or different. R represents a ketone group or a protective group that can be derived to a ketone group, and each may be the same or different. * Is the general formula (S1) or another structural unit. Represents the binding site of.)

(In the general formula (S2), Ar ^{5 to} Ar ⁸ represent an arbitrary divalent arylene group, which may be optionally substituted, but does not have an ionic group. Ar ^{5 to} Ar ⁸ is for each structural unit. R represents a ketone group or a protective group that can be induced by the ketone group, and may be the same or different from each other. * Is the general formula (S2) or other constituent units. Represents the binding site.)
Here, the protecting group that can be derived to a ketone group includes a protecting group that is generally used in organic synthesis, and represents a substituent that is temporarily introduced on the assumption that it is removed at a later stage. It can be restored to the original ketone group by protection.

Such protecting groups include, for example, Theodora W. Greene, "Protective Groups in Organic Syntheses", John Willie and Sons, USA, John Willie and Sons. Inc), 1981, and these are preferably used. The protecting group can be appropriately selected in consideration of the reactivity and yield of the protecting reaction and the deprotecting reaction, the stability of the protecting group-containing state, the production cost, and the like. In particular, a method of protecting / deprotecting the ketone moiety with a ketal moiety and a method of protecting / deprotecting the ketone moiety with a heteroatom analog of the ketal moiety, for example, thioketal, are preferably used.

As the structural unit containing a protecting group, a unit containing at least one selected from the following general formulas (U1) and (U2) is more preferable.

(In formulas (U1) and (U2), Ar ^{9 to} Ar ¹² are arbitrary divalent arylene groups, R ₁ and R ₂ are at least one group selected from H and alkyl groups, and R ₃ is arbitrary. The alkylene group and E represent O or S, each of which may represent two or more types of groups. The groups represented by the formulas (U1) and (U2) may be optionally substituted.)
Among them, in terms of the odor, reactivity, stability and the like of the compound, it is most preferable to use the structural unit in which E is O in the general formulas (U1) and (U2). That is, the method of protecting / deprotecting the ketone site with the ketal site is the most preferable.

The R ₁ and R ₂ in the general formula (U1) are more preferably alkyl groups in terms of stability, more preferably alkyl groups having 1 to 6 carbon atoms, and most preferably alkyls having 1 to 3 carbon atoms. Is the basis. Further, R ₃ in the general formula (U2) is more preferably an alkylene group having 1 to 7 carbon atoms in terms of stability, and most preferably an alkylene group having 1 to 4 carbon atoms. Specific examples of R ₃ include -CH ₂ CH _2- , -CH (CH ₃ ) CH _2- , -CH (CH ₃ ) CH (CH ₃ )-, -C (CH ₃ ) ₂ CH ₂ -,-. C (CH ₃ ) ₂ CH (CH ₃ )-, -C (CH ₃ ) ₂ O (CH ₃ ) _2- , -CH ₂ CH ₂ CH _2- , -CH ₂ C (CH ₃ ) ₂ CH ₂ -etc. However, it is not limited to these.

Among the structural units represented by the general formulas (U1) and (U2), those having at least the general formula (U2) are more preferably used from the viewpoint of stability such as hydrolysis resistance. Further, R ₃ of the general formula (U2) is preferably an alkylene group having 1 to 7 carbon atoms, that is, a group represented by C _n1 H _2n1 (n1 is an integer of 1 to 7), and is stable. , At least one selected from −CH ₂ CH ₂ −, −CH (CH ₃ ) CH ₂ −, or −CH ₂ CH ₂ CH ₂ − from the viewpoint of ease of synthesis is most preferable.

The deprotection reaction can be carried out under non-uniform or uniform conditions in the presence of water and acid, but from the viewpoint of mechanical strength, physical durability and solvent resistance, after molding into a film or the like. The method of acid treatment with is more preferable. Specifically, the molded membrane can be deprotected by immersing it in an aqueous hydrochloric acid solution or an aqueous sulfuric acid solution, and the acid concentration and the temperature of the aqueous solution can be appropriately selected.

The block polymer containing the structural units represented by the above general formulas (S1) and (S2) is an electron-attracting ketone group and all allylene groups are chemically treated when it is deprotected to form an electrolyte membrane. In addition, the physical durability is increased by toughening by imparting crystallinity and softening by lowering the glass transition temperature.

In the above general formulas (S1) and (S2), Ar ^{1 to} Ar ⁸ include hydrocarbon-based arylene groups such as a phenylene group, a naphthylene group, a biphenylene group, and a fluorinatedyl group, pyridinediyl, quinoxalindiyl, thiophendiyl, and the like. Heteroarylene group is preferably a phenylene group, and most preferably a p-phenylene group.

The content of the structural unit represented by the general formula (S1) contained in the segment (A1) containing an ionic group is more preferably 20 mol% or more, further preferably 50 mol% or more, and further preferably 80 mol% or more. Is the most preferable. The content of the structural unit represented by the general formula (S2) contained in the segment (A2) containing no ionic group is more preferably 20 mol% or more, further preferably 50 mol% or more, and 80. More than mol% is most preferable. When the content of the general formula (S2) contained in the segment (A2) containing no ionic group is less than 20 mol%, the mechanical strength due to crystallinity when the electrolyte membrane is obtained after deprotection. , The effect of the present invention on dimensional stability and physical durability tends to be insufficient.

A more preferable specific example of the structural unit represented by the general formula (S1) is a structural unit represented by the following general formula (P2) in terms of raw material availability. Among them, the structural unit represented by the following formula (P3) is more preferable, and the structural unit represented by the following formula (P4) is most preferable from the viewpoint of raw material availability and polymerizable property.

(In the formulas (P2), (P3) and (P4), M ^{1 to} M ⁴ represent hydrogen, metal cation and ammonium cation NR ₄ ⁺ (R is an arbitrary organic group), and M ^{1 to} M ⁴ are two or more kinds. R1 to r4 may independently represent an integer of 0 to 2, r1 + r2 may represent an integer of 1 to 8, and r1 to r4 may be different for each structural unit. , A ketone group or a protective group that can be derived from a ketone group, which may be the same or different. * Represents a binding site with the formulas (P2) (P3) (P4) or other structural units.)
The block polymer used in the present invention has a molar composition ratio (A1 / A2) of 0.2 or more between the segment containing an ionic group (A1) and the segment not containing an ionic group (A2). It is preferably 0.33 or more, more preferably 0.5 or more. Further, it is preferably 5 or less, more preferably 3 or less, and further preferably 2 or less. When A1 / A2 is less than 0.2 or more than 5, the proton conductivity under low humidification conditions tends to be insufficient, and the heat resistance and water resistance and physical durability tend to be insufficient.

The ion exchange capacity of the segment (A1) containing an ionic group is preferably 2.5 meq / g or more, more preferably 3 meq / g or more, still more preferably 3 meq / g or more, from the viewpoint of proton conductivity under low humidification conditions. It is 3.5 meq / g or more. Further, from the viewpoint of heat resistance and water resistance and physical durability, 6.5 meq / g or less is more preferable, 5 meq / g or less is more preferable, and 4.5 meq / g or less is further preferable.

The ion exchange capacity of the segment (A2) containing no ionic group is preferably 1 meq / g or less, more preferably 0.5 meq / g, from the viewpoint of heat resistance, mechanical strength, dimensional stability, and physical durability. More preferably, it is 0.1 meq / g or less.

When the block polymer has a sulfonic acid group, its ion exchange capacity is preferably 0.1 to 5 meq / g, more preferably 1.5 meq / g or more, still more preferably 1.5 meq / g or more, from the viewpoint of the balance between proton conductivity and water resistance. Is 2 meq / g or more. Further, 3.5 meq / g or less is more preferable, and 3 meq / g or less is more preferable. If the ion exchange capacity is smaller than 0.1 meq / g, the proton conductivity may be insufficient, and if it is larger than 5 meq / g, the water resistance may be insufficient.

In this specification, the ion exchange capacity is a value obtained by the neutralization titration method. The neutralization titration method is performed as follows. It should be noted that the measurement shall be performed three times or more and the average value shall be taken.
(1) After proton substitution and wiping off the water on the surface of the electrolyte membrane sufficiently washed with pure water, vacuum drying is performed at 100 ° C. for 12 hours or more to determine the dry weight.
(2) Add 50 mL of a 5 wt% sodium sulfate aqueous solution to the electrolyte and let stand for 12 hours for ion exchange.
(3) The generated sulfuric acid is titrated using a 0.01 mol / L sodium hydroxide aqueous solution. Add 0.1 w / v% of a commercially available phenolphthalein solution for titration as an indicator, and the point where it becomes pale reddish purple is the end point.
(4) The ion exchange capacity is calculated by the following formula.

Ion exchange capacity (meq / g) =
[Concentration of aqueous sodium hydroxide solution (mmol / ml) x amount dropped (ml)] / Dry weight of sample (g)
The method for synthesizing the oligomers constituting the ionic group-containing segment (A1) and the ionic group-free segment (A2) is not particularly limited as long as a method capable of obtaining a substantially sufficient molecular weight can be obtained. However, for example, it can be synthesized by utilizing an aromatic nucleophilic substitution reaction of an aromatic active dihalide compound and a divalent phenol compound, or an aromatic nucleophilic substitution reaction of a halogenated aromatic phenol compound.

As the aromatic active dihalide compound used for the synthesis of the oligomer constituting the segment (A1) containing an ionic group, the use of a compound in which an ionic group is introduced into the aromatic active dihalide compound as a monomer is chemically stable. It is preferable because the manufacturing cost and the amount of ionic groups can be precisely controlled. Preferable specific examples of the monomer having a sulfonic acid group as an ionic group include 3,3'-disulfonate-4,4'-dichlorodiphenylsulfone and 3,3'-disulfonate-4,4'-difluorodiphenyl. Sulfone, 3,3'-disulfonate-4,4'-dichlorodiphenylketone, 3,3'-disulfonate-4,4'-difluorodiphenylketone, 3,3'-disulfonate-4,4'-dichloro Examples thereof include diphenylphenylphosphine oxide, 3,3'-disulfonate-4,4'-difluorodiphenylphenylphosphine oxide, and the like. Among them, 3,3'-disulfonate-4,4'-dichlorodiphenylketone and 3,3'-disulfonate-4,4'-difluorodiphenylketone are more suitable in terms of chemical stability and physical durability. Preferably, 3,3'-disulfonate-4,4'-difluorodiphenyl ketone is most preferable from the viewpoint of polymerization activity.

Further, as the aromatic active dihalide compound having no ionic group used for the synthesis of the oligomer constituting the segment (A1) containing an ionic group and the oligomer constituting the segment (A2) not containing an ionic group, 4 , 4'-dichlorodiphenyl sulfone, 4,4'-difluorodiphenyl sulfone, 4,4'-dichlorodiphenyl ketone, 4,4'-difluorodiphenyl ketone, 4,4'-dichlorodiphenylphenylphosphine oxide, 4,4' -Difluorodiphenylphenylphosphine oxide, 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile, etc. can be mentioned. Among them, 4,4'-dichlorodiphenyl ketone and 4,4'-difluorodiphenyl ketone are more preferable from the viewpoint of imparting crystallinity, mechanical strength, physical durability, and heat resistance, and 4,4'-difluoro from the viewpoint of polymerization activity. Diphenyl ketones are most preferred. These aromatic active dihalide compounds can be used alone, but it is also possible to use a plurality of aromatic active dihalide compounds in combination.

Further, as a monomer having no ionic group used for synthesizing the oligomer constituting the segment (A1) containing an ionic group and the oligomer constituting the segment (A2) not containing an ionic group, a halogenated aromatic hydroxy compound. Can be mentioned. The segment can be synthesized by copolymerizing the compound with the above-mentioned aromatic active dihalide compound. The halogenated aromatic hydroxy compound is not particularly limited, but 4-hydroxy-4'-chlorobenzophenone, 4-hydroxy-4'-fluorobenzophenone, 4-hydroxy-4'-chlorodiphenylsulfone, 4-hydroxy -4'-fluorodiphenyl sulfone, 4- (4'-hydroxybiphenyl) (4-chlorophenyl) sulfone, 4- (4'-hydroxybiphenyl) (4-fluorophenyl) sulfone, 4- (4'-hydroxybiphenyl) Examples thereof include (4-chlorophenyl) ketone, 4- (4'-hydroxybiphenyl) (4-fluorophenyl) ketone, and the like. These can be used alone or as a mixture of two or more. Further, in the reaction of the activated dihalogenated aromatic compound and the aromatic dihydroxy compound, these halogenated aromatic hydroxy compounds may be reacted together to synthesize an aromatic polyether compound.

The method for synthesizing the block polymer is not particularly limited as long as it can obtain a substantially sufficient molecular weight, but for example, it does not contain the oligomer and the ionic group constituting the segment containing the ionic group. It can be synthesized by utilizing the aromatic nucleophilic substitution reaction of the oligomers constituting the segment.

In the aromatic nucleophilic substitution reaction performed to obtain an oligomer constituting a segment of a block polymer or to obtain a block polymer from the oligomer, the monomer mixture or the segment mixture is reacted in the presence of a basic compound. The polymerization can be carried out in a temperature range of 0 to 350 ° C., but is preferably a temperature of 50 to 250 ° C. If it is lower than 0 ° C., the reaction tends not to proceed sufficiently, and if it is higher than 350 ° C., decomposition of the polymer tends to start.

The polymerization reaction can be carried out without a solvent, but it is preferably carried out in a solvent. Examples of the solvent that can be used include N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, 1,3-dimethyl-2-imidazolidinone, hexamethylphosphontriamide and the like. The aprotic polar solvent of the above can be mentioned, but the solvent is not limited thereto, and any solvent may be used as a stable solvent in the aromatic nucleophilic substitution reaction. These organic solvents may be used alone or as a mixture of two or more kinds.

Examples of the basic compound used for the nucleophilic aromatic substitution reaction include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate and the like, and phenoxide structures in which aromatic diols are active are used. Anything that can be converted to can be used without being limited to these. It is also preferable to add a crown ether such as 18-crown-6 in order to enhance the nucleophilicity of phenoxide. These crown ethers may be coordinated with the sodium ion or potassium ion of the sulfonic acid group to improve the solubility in an organic solvent, and can be preferably used.

In the aromatic nucleophilic substitution reaction, water may be produced as a by-product. In this case, regardless of the polymerization solvent, toluene or the like can coexist in the reaction system to remove water as an azeotropic substance from the system. As a method of removing water from the system, a water absorbing agent such as a molecular sieve can also be used.

The azeotropic agent used to remove the reaction water or the water introduced during the reaction generally does not substantially interfere with the polymerization, is azeotropically distilled with water and boils between about 25 ° C. and about 250 ° C. Any inert compound. Common azeotropic agents include benzene, toluene, xylene, chlorobenzene, methylene chloride, dichlorobenzene, trichlorobenzene, cyclohexane and the like. Of course, it is beneficial to select an azeotropic agent that has a boiling point lower than the boiling point of the solvent. Azeotropes are commonly used, but they are not always required when high reaction temperatures, such as temperatures above 200 ° C., are used, especially when the reaction mixture is continuously sprayed with an inert gas. In general, the reaction is preferably carried out in the absence of oxygen in an inert atmosphere.

When the aromatic nucleophilic substitution reaction is carried out in a solvent, it is preferable to charge the monomer so that the obtained polymer concentration is 5 to 50% by weight. When the obtained polymer concentration is less than 5% by weight, the degree of polymerization tends to be difficult to increase. On the other hand, when it is more than 50% by weight, the viscosity of the reaction system becomes too high, and the post-treatment of the reaction product tends to be difficult.

After completion of the polymerization reaction, the solvent is removed from the reaction solution by evaporation, and if necessary, the residue is washed to obtain the desired polymer. Further, the reaction solution is added to a solvent having a low solubility of the polymer and a high solubility of the by-produced inorganic salt to remove the inorganic salt, the polymer is precipitated as a solid, and the polymer is obtained by filtration of the precipitate. You can also. The recovered polymer is optionally washed with water, alcohol or other solvent and dried. Once the desired molecular weight is obtained, the halide or phenoxide terminal group can optionally be reacted by introducing a phenoxide or halide terminal encapsulant that forms a stable terminal group.

As a block polymer used as an ionic group-containing aromatic hydrocarbon polymer, a phase-separated structure was observed when TEM observation was performed at a magnification of 50,000, and the average interlayer distance or average particle-to-particle distance measured by image processing was It is preferably 5 nm or more and 500 nm or less. Among them, those having an average interlayer distance or an average interparticle distance of 10 nm or more and 50 nm or less are more preferable, and those having an average interlayer distance of 15 nm or more and 30 nm or less are further preferable. If the phase-separated structure is not observed by a transmission electron microscope, or if the average interlayer distance or the average interparticle distance is less than 5 nm, the continuity of the ion channel may be insufficient and the conductivity may be insufficient. Further, if the interlayer distance exceeds 500 nm, the mechanical strength and dimensional stability may be poor.

The block polymer used as the ionic group-containing aromatic hydrocarbon-based polymer preferably has a crystallinity while having a phase-separated structure in terms of mechanical strength and proton conductivity. That is, it is preferable that crystallinity is recognized by differential scanning calorimetry (DSC) or wide-angle X-ray diffraction, and specifically, the amount of crystallization measured by differential scanning calorimetry is 0.1 J / g or more, or The crystallinity measured by wide-angle X-ray diffraction is preferably 0.5% or more. In addition, "having crystallinity" means that the polymer can be crystallized when the temperature rises, has a crystallinizable property, or has already crystallized. Further, the amorphous polymer means a polymer that is not a crystalline polymer and whose crystallization does not substantially proceed. Therefore, even if it is a crystalline polymer, if crystallization has not progressed sufficiently, the polymer may be in an amorphous state. The electrolyte membrane made of the crystalline polymer makes it possible to realize an electrochemical hydrogen pump and a water electrolyzer having better hydrogen compression power efficiency, water electrolysis efficiency and durability among hydrocarbon polymers.

In the electrolyte membrane of the present invention, the proton conductivity under low humidification, that is, the proton conductivity per unit area at 80 ° C. and a relative humidity of 25% (hereinafter, simply referred to as "proton conductivity") is 0. It is 12 S / cm ² or more. The proton conductivity is more preferably 0.2 mS / cm ² or more, and further preferably 0.3 mS / cm ² or more, in terms of miniaturization of the humidifier and hydrogen compression efficiency. Having a higher proton conductivity is preferable because a higher current density can be obtained at the same voltage, that is, more hydrogen can be compressed with the same energy.

In the electrolyte membrane of the present invention, the proton conductivity under humidification, that is, the proton conductivity under an atmosphere of 80 ° C. and 90% relative humidity is 8 S / cm ² or more. Proton Conductivity, in terms of water electrolysis efficiency, more preferably 10S / cm ² or more, further preferably 20S / cm ² or more. Having a higher proton conductivity is preferable because it allows higher current densities to be obtained at the same voltage, i.e., more hydrogen can be compressed or produced with the same energy.

Further, the hydrogen permeability of the electrolyte membrane of the present invention under an atmosphere of 80 ° C. and 90% relative humidity (hereinafter, simply referred to as “hydrogen permeability”) is 3.0 × ^10-7 cm ³ · (cm ² · s). -CmHg) ^-1 or less. If the hydrogen permeability is greater than ^{3.0 × 10 -7 cm 3 · (} cm 2 · s · cmHg) -1, the inverse transmission loss of the compressed hydrogen is increased in the electrochemical hydrogen pump, of that result, a hydrogen compression efficiency is reduced. Hydrogen permeability is more preferably in terms of hydrogen pressure Chijimiko rate ^{2.5 × 10 -7 cm 3 · (} cm 2 · s · cmHg) less than ^-1, 2.0 × ¹⁰ -7 cm ³ -(Cm ² · s · cmHg) ^-1 or less is more preferable. Here, the hydrogen permeability in the present invention represents the amount of hydrogen permeability of the membrane per unit area.

Further, from the viewpoint of pressure-resistant deformation (deformation resistance of the membrane to pressure) and creep resistance of the membrane, the tensile breaking strength of the electrolyte membrane having a width of 10 mm of the present invention under an atmosphere of 25 ° C. and a relative humidity of 60% (hereinafter referred to as , Simply referred to as "tensile breaking strength") needs to be 100,000 N or more. The tensile breaking strength is preferably 160,000 N or more, more preferably 200,000 N or more, still more preferably 240000 N or more. The larger the tensile breaking strength, the more preferable, but the larger the tensile strength, the larger the interface resistance with the catalyst layer tends to be. Therefore, the practical upper limit is 2000000 N. When the tensile breaking strength is less than 100,000 N, film rupture or the like under high pressure may easily occur due to insufficient pressure-resistant deformation and creep resistance.

The tensile elongation at break of the electrolyte membrane of the present invention is 150% or more, more preferably 180% or more, and most preferably 200% or more. The larger the tensile elongation at break is, the more preferable it is, but in terms of compatibility with the tensile strength at break, the practical upper limit is 1000%. If the tensile elongation at break is less than 150%, the toughness will be insufficient, and the hydrogen pump will continue to operate for a long time, or it will be used under conditions of repeated swelling and drying such as repeating the start and stop of the hydrogen pump. , The membrane may tear. The proton conductivity, hydrogen permeability, tensile breaking strength, and tensile breaking elongation of such an electrolyte membrane are determined according to the methods described in Examples described later.

The electrolyte membrane of the present invention is preferably manufactured as a polymer electrolyte membrane sheet continuously molded on a base material in terms of manufacturing efficiency, cost and membrane formation area, and the polymer electrolyte membrane sheet is rolled. It is more preferable to manufacture and supply the polymer electrolyte membrane roll that is wound in a shape. To meet the demand for larger compressed hydrogen such as hydrogen stations, it is necessary to increase the amount of hydrogen compressed in the electrochemical hydrogen pump, which is expected to increase the area of the electrolyte membrane used and the number of cells. In response to these demands for a large area and a large amount of electrolyte membrane, the polymer electrolyte membrane roll is superior to the sheet-shaped electrolyte membrane in terms of storage stability, transportability, manufacturing efficiency, and cost.

Electrochemical hydrogen pump for the polyelectrolyte membrane of the present invention preferably has a curling resistance is 80mm or less, and more preferably 50mm or less. When the curl property is larger than 80 mm, in a device for continuously forming a film, the film may come into contact with a transport path member during film transfer, causing scratches on the film surface or uneven film thickness. .. Such curl property is obtained according to the method described in Examples described later.

The film thickness of the electrolyte membrane of the present invention is preferably 20 μm or more and 200 μm or less. From the viewpoint of hydrogen barrier property and film strength, the film thickness is more preferably 25 μm or more, and further preferably 30 μm or more. Further, in terms of proton conductivity, 150 μm or less is more preferable, and 60 μm or less is further preferable. If the film thickness is less than 20 μm, the hydrogen barrier property and the pressure resistance of the film may decrease. On the other hand, if the thickness is thicker than 200 [mu] m, with the proton conductivity decreases, there is a case where the hydrogen pressure Chijimiko rate decreases. The film thickness of the electrolyte membrane can be controlled by the solution concentration, the coating thickness on the substrate, or the like.

As described in the above-mentioned known literature, a conventional film made of a perfluoropolymer cannot maintain the hydrogen barrier property and the pressure resistance of the film unless the film is thicker than 150 μm due to its low hydrogen barrier property and low tensile breaking strength. , it is difficult to use in the electrochemical hydrogen pump. On the other hand, the electrolyte membrane made of an ionic group-containing aromatic hydrocarbon-based polymer can achieve both high tensile strength at break and low hydrogen permeability. Therefore, it can also be applied to the electrochemical hydrogen pump with a thin film such 20Myuemu～200myuemu, such material cost reduction and a hydrogen pressure Chijimiko rate gains associated with thinning provides the new dominant effect over the prior art.

The film thickness of the electrolyte membrane of the present invention preferably has a variation of ± 5% or less in the MD and TD directions, and more preferably ± 3% or less. When the film thickness variation is larger than ± 5%, the current is concentrated in the portion where the film thickness is thin, so that local stress is applied to the electrolyte membrane, which may cause problems such as local pinholes. Such film thickness variation is obtained according to the method described in Examples described later.

<Manufacturing method of polymer electrolyte membrane>
As an example, the polymer electrolyte membrane of the present invention can be produced by a production method including a step of casting and coating a polymer electrolyte membrane precursor solution on a substrate to form a polymer electrolyte membrane.

The present inventors have focused on the curl property and film thickness uniformity of the method for producing a hydrocarbon-based electrolyte membrane for an electrochemical hydrogen pump as problems, and have set these problems as the film-forming substrate thickness and the precursor coating viscosity. It was found that a uniform thick film can be produced as a continuous roll by solving the problem by optimizing the above and drying conditions.

The thickness T1 of the base material used for film formation in the production method can be appropriately selected according to the thickness T2 of the electrolyte membrane, but is a group having a thickness that satisfies the following (Equation 1) in terms of curlability and transportability. It is preferable to use a material.
7 ≦ T1 / T2 ≦ 15 (Equation 1)
If T1 / T2 is less than 7, the curl of the electrolyte membrane may cause scratches on the membrane surface or uneven film thickness, especially during roll transfer, and if it is greater than 15, handling may deteriorate. , The cost may be high. From the viewpoint of cost, T1 / T2 is more preferably 12 or less, and further preferably 10 or less.

The base material thickness T1 is preferably 600 μm or less, more preferably 550 μm or less, further preferably 500 μm or less, and most preferably 400 μm or less in terms of cost and handling. Regarding the base material thickness T2, there is no particular lower limit as long as it is within the range satisfying Equation 1, but in reality, it is 200 μm or more.

Known materials can be used as the base material used for film formation, but endless belts and drums made of metals such as stainless steel, films made of polymers such as polyethylene terephthalate, polyimide, polyphenylene sulfide, and polysulfone, glass, and release paper are used. Can be mentioned. For metals, the surface is mirror-treated, for polymer films, the coated surface is corona-treated, for peeling, and for continuous roll-shaped coating, the back of the coated surface is peeled and rolled. It is also possible to prevent the electrolyte film and the back side of the coating base material from adhering after being removed.

The solvent used for film formation may be any solvent that can dissolve the electrolyte membrane precursor and then remove it, for example, N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone. , Dimethylsulfoxide, sulfolane, aprotic polar solvents such as 1,3-dimethyl-2-imidazolidinone, hexamethylphosphontriamide, ester solvents such as γ-butyrolactone and butyl acetate, carbonates such as ethylene carbonate and propylene carbonate. A system solvent, an alkylene glycol monoalkyl ether such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, or propylene glycol monoethyl ether, or an alcohol solvent such as isopropanol, water, and a mixture thereof are preferably used. However, an aprotic polar solvent has the highest solubility and is preferable. It is also preferable to add a crown ether such as 18-crown-6 in order to increase the solubility of the ionic group-containing component.

The viscosity of the electrolyte membrane precursor solution is preferably 75 poise or more and 1000 poise or less in terms of film thickness uniformity and film forming property. If the solution viscosity is greater than 1000 poise, the high viscosity tends to make coating difficult. On the other hand, when the viscosity of the solution is less than 75 poise, the coating liquid flows after the solution is cast and applied to the base material, resulting in non-uniform film thickness or deterioration of the film quality due to the base material repelling the coating liquid. There is a risk of The solution viscosity is determined according to the method described in Examples described later. In terms of film quality, the solution viscosity is more preferably 90 poise or more, and even more preferably 100 poise or more. Similarly, it is more preferably 500 poise or less, and most preferably 250 poise or less.

The electrolyte membrane precursor solution prepared to have the required solid content concentration and viscosity is subjected to normal pressure filtration or pressure filtration to remove foreign substances present in the polymer electrolyte solution in order to obtain a tough membrane. This is the preferred method. The filter medium used here is not particularly limited, but a glass filter or a metallic filter is preferable. In the filtration, the pore size of the minimum filter through which the polymer solution passes is preferably 1 μm or less.

As a casting method of the electrolyte membrane precursor solution on the substrate, knife coat, direct roll coat, gravure coat, spray coat, brush coat, dip coat, die coat, vacuum die coat, curtain coat, flow coat, spin Techniques such as coating, reverse coating, and screen printing can be applied. In forming the electrolyte membrane, a roll-shaped base material is unwound, the salivation coating method is applied, and the coating is continuously applied with a uniform film thickness in the traveling direction and the width direction, which is the vertical direction thereof, and then again. The method of winding in a roll is suitable. In such a method, die coating is preferable from the viewpoint of the viscosity and film thickness of the electrolyte membrane precursor solution. Further, in terms of curl property and drying efficiency, intermittent coating of the electrolyte membrane precursor solution using these casting coating methods is also used. By using intermittent coating, the solvent vapor concentration in the drying furnace can be reduced, which improves the drying efficiency of the electrolyte membrane precursor solution and suppresses curling of the electrolyte membrane during roll transfer. Can be done. The ratio of the length of the intermittent portion to the coated portion can be appropriately selected depending on the physical characteristics of the electrolyte membrane, the drying conditions, and the like.

Next, the film obtained by casting is preferably heat-treated with at least a part of ionic groups in the state of a metal salt. If the polymer electrolyte material used is one that polymerizes in the state of a metal salt at the time of polymerization, it is preferable to form a film and heat-treat it as it is. The metal of the metal salt may be any one capable of forming a salt with an ionic group, but from the viewpoint of price and environmental load, Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Ti, V , Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, W and the like, among these, Li, Na, K, Ca, Sr and Ba are more preferable, and Li, Na and K are even more preferable. The temperature of this heat treatment is preferably 80 to 350 ° C., more preferably 100 to 200 ° C., and particularly preferably 120 to 150 ° C. The heat treatment time is preferably 10 seconds to 12 hours, more preferably 30 seconds to 6 hours, and particularly preferably 1 minute to 1 hour. If the heat treatment temperature is too low, mechanical strength and physical durability may be insufficient. On the other hand, if it is too high, the chemical decomposition of the membrane material may proceed. Further, if the heat treatment time is less than 10 seconds, the effect of improving the mechanical strength and physical durability by the heat treatment may be insufficient. On the other hand, if it exceeds 12 hours, deterioration of the electrolyte membrane is likely to occur.

Further, in the production method of the present invention, it is preferable to have a step of evaporating the solvent from the base material to which the electrolyte membrane precursor solution is cast and coated. The amount of residual solvent in the polymer electrolyte membrane after evaporation of the solvent in the evaporation step is preferably 10% by mass or less, more preferably 8% by mass or less, and further preferably 5% by mass or less. .. If the amount of residual solvent is more than 10% by mass, the solvent may bleed out to the surface during storage of the electrolyte membrane, resulting in deterioration of membrane quality or deterioration of membrane physical properties, especially hydrogen barrier property and mechanical strength. is there. The amount of residual solvent can be appropriately adjusted depending on the concentration of the coating liquid, the length of the drying oven, the temperature of the drying oven, the amount of hot air, the exhaust, the transport speed, and the like. The amount of residual solvent is determined according to the method described in Examples described later.

The polymer electrolyte membrane obtained by heat-treating the cast-coated membrane can be proton-substituted by immersing it in an acidic aqueous solution, if necessary. By molding the electrolyte membrane by this method, the polymer electrolyte membrane can achieve both proton conductivity and physical durability in a better balance.

<Electrolyte membrane with catalyst layers, membrane electrode assembly and electrochemical hydrogen pump>
Cells used in the electrochemical hydrogen pump, the catalyst layer on both surfaces of the electrolyte membrane of the present invention, the electrode substrate and the separator are sequentially stacked. Of these, the one in which the catalyst layer is laminated on both sides of the electrolyte membrane (that is, the one having a layer structure of the catalyst layer / electrolyte membrane / catalyst layer) is called an electrolyte membrane with a catalyst layer (CCM), and is called an electrolyte membrane with a catalyst layer (CCM). The catalyst layer and the gas diffusion base material in which the catalyst layer and the gas diffusion base material are sequentially laminated (that is, the layer structure of the gas diffusion base material / catalyst layer / electrolyte membrane / catalyst layer / gas diffusion base material) are the same as the film electrode composite (MEA). It is called.

As a method for producing CCM, a coating method in which a catalyst layer paste composition for forming a catalyst layer is applied and dried on the surface of an electrolyte membrane or only a catalyst layer is prepared on a substrate and the catalyst layer is transferred. As a result, a method of laminating the catalyst layer on the electrolyte membrane (transfer method) is generally performed.

The peel strength between the electrolyte membrane and the catalyst layer in CCM is preferably 5 N / cm or more from the viewpoint of reducing the interfacial resistance between the electrolyte membrane and the catalyst layer and maintaining durability in long-term operation. The peel strength is more preferably 7 N / cm or more, and further preferably 10 N / cm or more. The peel strength is determined according to the method described in Examples described later.

An electrolyte membrane roll with a catalyst layer in which CCM is continuously formed on a substrate and wound in a roll shape is also a preferred embodiment of the present invention.

When MEA is prepared by pressing, a known method (for example, Electrochemistry, 1985, 53, p. 269., Chemical plating method, edited by The Electrochemical Society (J. Electrochem. Soc.), Electrochemical Science and Technology (Electrochemical Science and Technology), 1988, 135, 9, p.2209. Hot press bonding method of gas diffusion electrode, etc.) can be applied. The temperature and pressure at the time of pressing may be appropriately selected depending on the thickness of the electrolyte membrane, the water content, the catalyst layer and the electrode base material. Further, in the present invention, compounding by pressing is possible even when the electrolyte membrane is in a dry state or in a water-absorbing state. Specific press methods include roll presses that regulate pressure and clearance, flat plate presses that regulate pressure, etc., and are 0 from the viewpoint of industrial productivity and suppression of thermal decomposition of polymer materials having ionic groups. It is preferably carried out in the range of ° C. to 250 ° C. From the viewpoint of protecting the electrolyte film and electrodes, the pressurization is preferably as weak as possible within the range in which the adhesion between the electrolyte film and the catalyst layer is maintained, and in the case of a flat plate press, a pressure of 10 MPa or less is preferable, and compounding by the pressing process is performed. it is also an anode, which is one of the preferred choices in view of prevention of short-circuit the cathode electrode of the cell of the electrodes and superposing the electrolyte membrane for electrochemical hydrogen pump without performing. In this way, when repeated operation as the electrochemical hydrogen pump, there is a tendency that deterioration of the electrolyte membrane short-circuited portion is presumed cause is suppressed, the durability of the electrochemical hydrogen pump Becomes good. Further, in the control of press conditions, it is possible to raise the temperature after pressurization, hold it at a predetermined pressure and temperature, then lower the temperature while maintaining the pressure, and then release the pressure without wrinkles or peeling. It is preferable in that an electrolyte membrane with a uniform catalyst layer can be obtained. If the temperature is raised while pressurizing or the pressure is released before the temperature is lowered, three-dimensional thermal shrinkage occurs when the interface between the electrolyte membrane and the catalyst layer is not fixed, causing wrinkles and peeling due to poor adhesion. It may occur.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. Here, Example 1 shall be read as Reference Example 1. The measurement conditions for each physical property are as follows.

(1) Ion exchange capacity (IEC)
It was measured by the neutralization titration method described in (i) to (iv) below. The measurement was performed three times and the average value was taken.
(I) After proton substitution and wiping off the moisture on the surface of the electrolyte membrane sufficiently washed with pure water, vacuum drying was performed at 100 ° C. for 12 hours or more to determine the dry weight.
(Ii) 50 mL of a 5 wt% sodium sulfate aqueous solution was added to the electrolyte, and the mixture was allowed to stand for 12 hours for ion exchange.
(Iii) The resulting sulfuric acid was titrated using a 0.01 mol / L sodium hydroxide aqueous solution. A commercially available phenolphthalein solution for titration of 0.1 w / v% was added as an indicator, and the point at which it became pale reddish purple was defined as the end point.
(Iv) The ion exchange capacity was calculated by the following formula.

Ion exchange capacity (meq / g) =
[Concentration of aqueous sodium hydroxide solution (mmol / mL) x amount dropped (mL)] / dry weight of sample (g)]
(2) Proton conductivity After immersing a film-like sample in pure water at 25 ° C for 24 hours, hold it in a constant temperature and humidity chamber at 80 ° C and a relative humidity of 25 to 95% for 30 minutes at each step to achieve a constant potential. The proton conductivity was measured by the AC impedance method.

As a measuring device, a Solartron electrochemical measurement system (Solartron 1287 Electrical Interface and Solartron 1255B Frequency Response Analoger) was used, and constant potential impedance was measured by a two-terminal method to determine proton conductivity. The AC amplitude was 50 mV. A film having a width of 10 mm and a length of 50 mm was used as the sample. The measuring jig was made of phenol resin, and the measuring part was opened. A platinum plate (thickness 100 μm, 2 plates) was used as the electrode. The electrodes were arranged at a distance of 10 mm between the electrodes on the front side and the back side of the sample film so as to be parallel to each other and orthogonal to the longitudinal direction of the sample film.

(3) Number average molecular weight and weight average molecular weight The number average molecular weight and weight average molecular weight of the polymer were measured by GPC. N-methyl using HLC-8022GPC manufactured by Tosoh Corporation as an integrated device of an ultraviolet detector and a differential refractometer, and two TSK gel SuperHM-H (inner diameter 6.0 mm, length 15 cm) manufactured by Tosoh Corporation as a GPC column. Measured with a -2-pyrrolidone solvent (N-methyl-2-pyrrolidone solvent containing 10 mmol / L of lithium bromide) at a sample concentration of 0.1% by weight, a flow rate of 0.2 mL / min, and a temperature of 40 ° C., and standardized. The number average molecular weight and the weight average molecular weight were determined by polystyrene conversion.

(4) Film thickness and film thickness variation Measurement was performed using a Mitutoyo ID-C112 type set on a Mitutoyo granite comparator stand BSG-20.

For the film thickness variation, for example, when the electrolyte membrane is in the form of a sheet, the four corners, the points where each side is divided into n equal parts so that the side length after equal division is less than 3 cm, and the central part are measured, and they are measured. Find the average value of. The average value is defined as the film thickness of the electrolyte membrane. Obtain the difference between the average value and each film thickness measurement value, and determine the maximum and minimum values. The maximum value and the minimum value are each divided by the average value, and the value multiplied by 100 is used as the film thickness variation. When the electrolyte membrane is roll-shaped, the TD direction is calculated in the same manner as above by measuring each point divided into n equal parts so that the side length after equal division of both ends and the TD side is less than 3 cm. To do. The MD direction is calculated in the same manner as above by measuring the start and end of the electrolyte membrane and each point obtained by equally dividing the MD roll length into n equal parts so that the length is less than 1 m.

(5) Purity measurement method Quantitative analysis was performed by gas chromatography (GC) under the following conditions.
Column: DB-5 (manufactured by J & W) L = 30m Φ = 0.53mm D = 1.50μm
Carrier: Helium (linear velocity = 35.0 cm / sec)
Analytical conditions Inj. temperature. 300 ° C
Dect. temperature. 320 ° C
Oven; 50 ° C x 1 min
Rate; 10 ° C / min
Final; 300 ° C x 15 min
SP ratio; 50: 1
(6) Nuclear magnetic resonance spectrum (NMR)
Under the following measurement conditions, ^{1 1} H-NMR measurement was carried out, the structure was confirmed, and the molar composition ratio of the segment containing an ionic group (A1) and the segment not containing an ionic group (A2) was quantified. The molar composition ratios were 8.2 ppm (derived from disulfonate-4,4'-difluorobenzophenone) and 6.5-8.0 ppm (derived from total aromatic protons excluding disulfonate-4,4'-difluorobenzophenone). It was calculated from the integrated value of the recognized peaks.

Equipment: EX-270 manufactured by JEOL Ltd.
Resonance frequency: 270 MHz ( ^{1 1} H-NMR)
Measurement temperature: Room temperature Dissolving solvent: DMSO-d6
Internal reference material: TMS (0 ppm)
Number of integrations: 16 times (7) Tensile strength / elongation measurement After leaving the polymer electrolyte membrane as a sample at 25 ° C. and 60% RH for 24 hours, set it in the device and measure the tensile strength / elongation under the following conditions. went. The tensile strength and elongation was calculated as an average value of 5 tests.

Measuring device: SV-201 type tensile compression tester (manufactured by Imada Seisakusho)
Load: 50N
Tensile speed: 10 mm / min
Specimen: width 5 mm x length 50 mm
Distance between samples: 20 mm
Test temperature: 25 ° C, 60% RH
Number of tests: n = 5
(8) Hydrogen permeability measurement With the polymer electrolyte membrane as a sample as a boundary, hydrogen gas was supplied to one side and the other side was evacuated to give a pressure difference to allow hydrogen gas to permeate. After the hydrogen gas became a steady state, the vacuum exhaust was stopped, and the hydrogen gas that had permeated the electrolyte membrane was stored in the measuring tube within the time t from that time. The stored gas was quantified by a thermal conductivity detector, and the transmittance P for hydrogen gas was calculated from the following formula.

Q = P × L × (p _h − _pl ) / L × A × t
Here, Q is the hydrogen gas permeation amount (cm ³ ), P is the hydrogen gas permeability, _ph is the high pressure side pressure of the hydrogen gas, _pl is the low pressure side pressure of the hydrogen gas = 0, and L is the thickness of the electrolyte film (L). cm), A represents the permeation area of hydrogen gas in the electrolyte membrane (cm ² ), and t represents the time (permeation time) (s) for storing the permeated gas.

The measurement conditions are as follows.

Equipment: Differential pressure type gas permeability measurement system manufactured by GTR Tech Co., Ltd. Measurement temperature: 80 ° C
Humidity: 90%
Test gas: Mixed gas of dry hydrogen and water vapor Hydrogen gas Partial pressure: 44 cmHg
Gas permeation area: 15.2 cm ²
Number of measured n: 2
(9) Curling property The electrolyte membrane is cut into 20 cm squares with the base material attached, placed on a horizontal surface, and allowed to stand in a temperature-controlled humidity atmosphere with a temperature of 23 ° C. ± 5 ° C. and a humidity of 50% ± 5% for 24 hours, and then curled. Measure the distance = curl property between the edge of the electrolyte membrane and the horizontal plane.

(10) made work of the catalyst layer with electrolyte membrane (CCM)

Commercially available Teflon is a catalyst ink prepared by adjusting the platinum catalyst TEC10E50E manufactured by Tanaka Kikinzoku Kogyo Co., Ltd. and Nafion (registered trademark) "(" Nafion (registered trademark) ") manufactured by DuPont to a weight ratio of 2: 1. (Registered trademark) The amount of platinum on the film is 0.3 mg / cm ² The catalyst layer transfer film A100 was prepared.

A pair of catalyst layer transfer films cut into 5 cm squares are prepared, laminated so as to sandwich the polymer electrolyte membrane to be evaluated, and the temperature is raised from the pressurized state to 3 at 150 ° C. and 5 MPa. A heating press was performed for 1 minute, the temperature was lowered to 40 ° C. or lower in a pressurized state, and then the pressure was released to obtain an electrolyte membrane with a catalyst layer for an electrochemical hydrogen pump.

(12) Peeling strength measurement

Superimposed to face those cuts before Symbol catalyst layer transfer film A100 and the polymer electrolyte membrane to 20cm square each, was warmed from pressurized state, 0.99 ° C., for 3 minutes thermally pressed at 5 MPa, pressing The temperature was lowered to 40 ° C. or lower in the pressurized state, the pressure was released, and the Teflon (registered trademark) film was peeled off .

On the surface from which the Teflon film was peeled off, another Teflon sheet of 5 cm × 15 cm and an electrolyte membrane cut into 20 cm squares were laminated in order so that the 20 cm sides were aligned with the edges, and the temperature was raised again from the pressurized state. A heating press was performed at 150 ° C. and 5 MPa for 3 minutes, the temperature was lowered to 40 ° C. or lower in a pressurized state, and then the pressure was released to obtain an electrolyte membrane with a catalyst layer for measuring peel strength.

Further, for the catalyst layer transfer film A200, an electrolyte membrane with a catalyst layer for measuring peel strength was obtained in the same manner.

Remove the Teflon film sandwiched between them, and sandwich it with the part where the Teflon film was not sandwiched.
It was cut into strips of 25 mm width x 20 cm so that both parts were included.

The part where the electrolyte membrane and the catalyst layer are not in close contact with each other due to the Teflon film being sandwiched is sandwiched between the upper and lower chucks of a tensile tester (A & D, Tencilon RTG-1210), and a T-shaped peeling test is performed according to JIS K 6854-3. The peel strength of the close contact portion was measured.

(13) Hydrogen compression evaluation
The membrane electrode assembly for an electrochemical hydrogen pump is a JARI standard cell "Ex-1" manufactured by Eiwa Co., Ltd. (electrode area 25 cm). ² ), The cell temperature was set to 40 ° C., and hydrogen humidified to 100% RH was supplied to one electrode (hydrogen supply electrode: cathode) at atmospheric pressure at a flow rate of 1 L / min.

The other electrode (hydrogen compressed electrode: anode) has a structure in which the pressure can be controlled by a back pressure valve.
Before the evaluation, it was purged with 100% RH nitrogen gas so that the pressure became atmospheric pressure.

Synthesis Example 1: Synthesis of block copolymer b1

( 2,2-bis (4-hydroxyphenyl) -1,3- represented by the following general formula (G1)
Synthesis of dioxolane (K-DHBP))

49.5 g of 4,4'-dihydroxybenzophenone (DHBP), 134 g of ethylene glycol, 96.9 g of trimethyl orthoformate and p-toluenesulfonic acid monohydrate in a 500 mL flask equipped with a stirrer, thermometer and distillate. Add 0.50 g and dissolve. Then, the mixture was kept warm and stirred at 78 to 82 ° C. for 2 hours. Further, the internal temperature was gradually raised to 120 ° C., and the mixture was heated until the distillation of methyl formate, methanol and trimethyl orthoformate was completely stopped. After cooling the reaction solution to room temperature, the reaction solution was diluted with ethyl acetate, the organic layer was washed with 100 mL of a 5% potassium carbonate aqueous solution, separated, and then the solvent was distilled off. 80 mL of dichloromethane was added to the residue to precipitate crystals, which were filtered and dried to obtain 52.0 g of 2,2-bis (4-hydroxyphenyl) -1,3-dioxolane. GC analysis of this crystal revealed 99.8% 2,2-bis (4-hydroxyphenyl) -1,3-dioxolane and 0.2% 4,4'-dihydroxybenzophenone.

(Synthesis of disodium 3,3'-disulfonate-4,4'-difluorobenzophenone represented by the following general formula (G2))

109.1 g (Aldrich reagent) of 4,4'-difluorobenzophenone was reacted in 150 mL (Wako Pure Chemicals reagent) of fuming sulfuric acid (50% SO3) at 100 ° C. for 10 hours. Then, it was gradually added to a large amount of water, neutralized with NaOH, and then 200 g of salt was added to precipitate the synthetic product. The obtained precipitate was separated by filtration and recrystallized from an aqueous ethanol solution to obtain disodium 3,3'-disulfonate-4,4'-difluorobenzophenone represented by the above general formula (G2). The purity was 99.3%. The structure was confirmed by ^{1 1} H-NMR. Impurities were quantitatively analyzed by capillary electrophoresis (organic matter) and ion chromatography (inorganic matter).

(Synthesis of oligomer a1'containing no ionic group represented by the following general formula (G3))

(In equation (G3), m represents a positive integer.)
16.59 g of potassium carbonate (Aldrich reagent, 120 mmol), 25.8 g of K-DHBP (100 mmol) and 4,4'-difluorobenzophenone 20. In a 1000 mL three-necked flask equipped with a stirrer, nitrogen introduction tube and Dean-Stark trap. 3 g (Aldrich reagent, 93 mmol) was added, and after nitrogen substitution, dehydration was performed in 300 mL of N-methylpyrrolidone (NMP) and 100 mL of toluene at 160 ° C., the temperature was raised to remove toluene, and polymerization was performed at 180 ° C. for 1 hour. .. Purification is performed by reprecipitation with a large amount of methanol to obtain an oligomer a1 containing no ionic group (terminal OM group, M of OM group represents Na or K, and the notation thereafter follows this). It was. The number average molecular weight was 10,000.

In a 500 mL three-necked flask equipped with a stirrer, a nitrogen introduction tube, and a Dean-Stark trap, 1.1 g of potassium carbonate (Aldrich reagent, 8 mmol) and 20.0 g of the oligomer a1 (terminal OM group) containing no ionic group (terminal OM group). 2 mmol) is added, and after nitrogen substitution, dehydration is performed in 100 mL of N-methylpyrrolidone (NMP) and 30 mL of cyclohexane at 100 ° C., the temperature is raised to remove cyclohexane, and 4.0 g of decafluorobiphenyl (Aldrich reagent, 12 mmol) is added. And the reaction was carried out at 105 ° C. for 1 hour. Purification was carried out by reprecipitation with a large amount of methanol to obtain an oligomer a1'(terminal fluoro group) containing no ionic group represented by the above formula (G3). The number average molecular weight was 11000, and the number average molecular weight of the oligomer a1'containing no ionic group was determined to be a value of 10400 after subtracting the linker moiety (molecular weight 630).

(Synthesis of oligomer a2 containing an ionic group represented by the following general formula (G4))

(In formula (G4), M represents Na or K.)
27.6 g of potassium carbonate (Aldrich reagent, 200 mmol), 12.9 g of K-DHBP (50 mmol) and 9.3 g of 4,4'-biphenol in a 1000 mL three-necked flask equipped with a stirrer, nitrogen introduction tube and Dean-Stark trap. (Aldrich Reagent, 50 mmol), disodium 3,3'-disulfonate-4,4'-difluorobenzophenone 40.6 g (96 mmol), and 18-crown-6 ether 17.9 g (Wako Pure Chemicals, 82 mmol) were added. After nitrogen substitution, dehydration was carried out in 300 mL of N-methylpyrrolidone (NMP) and 100 mL of toluene at 170 ° C., the temperature was raised to remove toluene, and polymerization was carried out at 180 ° C. for 1 hour. Purification was carried out by reprecipitation with a large amount of isopropyl alcohol to obtain an oligomer a2 (terminal OM group) containing an ionic group represented by the above formula (G4). The number average molecular weight was 29000.

(Synthesis of Polyketal Ketone (PKK) -based block copolymer b1 containing oligomer a2 as a segment (A1) containing an ionic group, oligomer a1 as a segment (A2) not containing an ionic group, and octafluorobiphenylene as a linker moiety. )
In a 500 mL three-necked flask equipped with a stirrer, a nitrogen introduction tube, and a Dean-Stark trap, add 0.56 g of potassium carbonate (Aldrich reagent, 4 mmol) and 29 g (1 mmol) of oligomer a2 (terminal OM group) containing an ionic group. After adding and substituting with nitrogen, dehydrate in 100 mL of N-methylpyrrolidone (NMP) and 30 mL of toluene at 100 ° C., then raise the temperature to remove toluene, and 11 g of oligomer a1'(terminal fluoro group) containing no ionic group (terminal fluoro group). 1 mmol) was added, and the reaction was carried out at 105 ° C. for 24 hours. Purification was carried out by reprecipitation with a large amount of isopropyl alcohol to obtain block copolymer b1. The weight average molecular weight was 400,000.

The block copolymer b1 contains 50 mol% of the structural unit represented by the general formula (S1) as the segment (A1) containing an ionic group, and the segment (A2) containing no ionic group as the general formula (S1). It contained 100 mol% of the structural unit represented by S2).

When the block copolymer b1 itself is used as a polymer electrolyte membrane, the ion exchange capacity determined by neutralization titration is 2.1 meq / g, and the molar composition ratio (A1 / A2) determined from ¹ H-NMR is 56 mol / g. 44 mol = 1.27, no residual ketal group was observed.

Synthesis example 2
(Synthesis of hydrophobic oligomer-a3 represented by the following formula (G5))

49.4 g (0.29 mol), 2,2-bis (0.29 mol) of 2,6-dichlorobenzonitrile in a 1 L three-necked flask equipped with a stirrer, a thermometer, a cooling tube, a Dean-Stark tube, and a three-way cock for introducing nitrogen. 4-Hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane 88.4 g (0.26 mol) and potassium carbonate 47.3 g (0.34 mol) were weighed.

After nitrogen substitution, 346 mL of sulfolane and 173 mL of toluene were added and stirred. The flask was placed in an oil bath and heated to reflux at 150 ° C. When the water produced by the reaction was azeotroped with toluene and the reaction was carried out while removing it from the system with a Dean-Stark tube, almost no water production was observed in about 3 hours. After removing most of the toluene while gradually increasing the reaction temperature, the reaction was continued at 200 ° C. for 3 hours. Next, 12.3 g (0.072 mol) of 2,6-dichlorobenzonitrile was added, and the reaction was further carried out for 5 hours.

The obtained reaction solution was allowed to cool, and then 100 mL of toluene was added to dilute it. The precipitate of the by-produced inorganic compound was removed by filtration, and the filtrate was put into 2 L of methanol. The precipitated product was separated by filtration, collected, dried, and then dissolved in 250 mL of tetrahydrofuran. This was reprecipitated in 2 L of methanol to obtain 107 g of the target oligomer a3. The number average molecular weight of the oligomer a3 was 7,400.

Synthesis example 3
(Synthesis of hydrophilic monomer a4 represented by the following formula (G6))

233.0 g (2 mol) of chlorosulfonic acid was added to a 3 L three-necked flask equipped with a stirrer and a cooling tube, and then 100.4 g (400 mmol) of 2,5-dichlorobenzophenone was added and reacted in an oil bath at 100 ° C. for 8 hours. After a predetermined time, the reaction solution was slowly poured into 1000 g of crushed ice and extracted with ethyl acetate. The organic layer was washed with saline, dried with magnesium sulfate, ethyl acetate was distilled off, and pale yellow crude crystals 3 -(2,5-Dichlorobenzoyl) benzenesulfonic acid chloride was obtained. The crude crystals were not purified and used as they were in the next step.

38.8 g (440 mmol) of 2,2-dimethyl-1-propanol (neopentyl alcohol) was added to 300 mL of pyridine and cooled to about 10 ° C. The crude crystals obtained above were gradually added thereto over about 30 minutes. After the total amount was added, the mixture was further stirred for 30 minutes to react. After the reaction, the reaction solution was poured into 1000 mL of hydrochloric acid water, and the precipitated solid was recovered. The obtained solid was dissolved in ethyl acetate, washed with aqueous sodium hydrogen carbonate solution and brine, dried over magnesium sulfate, and ethyl acetate was distilled off to obtain crude crystals. This was recrystallized from methanol to obtain white crystals of neopentyl a4 3- (2,5-dichlorobenzoyl) benzenesulfonate represented by the following structural formula.

Synthesis Example 4: Synthesis of block copolymer b2 (Synthesis of polyarylene-based block copolymer b2 represented by the following formula (G7))

13.4 g (1.8 mmol) of a hydrophobic oligomer obtained by synthesizing 166 mL of dried N, N-dimethylacetamide (DMAc) in Synthesis Example 2 in a 1 L three-necked flask connected to a stirrer, a thermometer, and a nitrogen introduction tube. 37.6 g (93.7 mmol) of neopentyl 3- (2,5-dichlorobenzoyl) benzenesulfonate, 2.62 g (4.0 mmol) of bis (triphenylphosphine) nickel dichloride, triphenylphosphine 10 synthesized in Synthesis Example 3. It was added under nitrogen to a mixture of 5.5 g (40.1 mmol), sodium iodide 0.45 g (3.0 mmol) and zinc 15.7 g (240.5 mmol).

The reaction system was heated under stirring (finally heated to 82 ° C.) and reacted for 3 hours. An increase in viscosity in the system was observed during the reaction. The polymerization reaction solution was diluted with 175 mL of DMAc, stirred for 30 minutes, and filtered using Celite as a filtration aid. Add 24.4 g (281 mmol) of lithium bromide to this filtrate in 3 portions of 1/3 at 1 hour intervals with 3 mouths of 1 L equipped with a stirrer, and add at 120 ° C. for 5 hours in a nitrogen atmosphere. It was reacted. After the reaction, the mixture was cooled to room temperature, poured into 4 L of acetone, and solidified. The coagulated product was collected by filtration, air-dried, pulverized with a mixer, and washed with 1500 mL of 1N sulfuric acid while stirring. After filtration, the product was washed with ion-exchanged water until the pH of the washing solution reached 5 or higher, and then dried at 80 ° C. overnight to obtain 38.0 g of the target block copolymer b2. The weight average molecular weight of this block copolymer was 170,000.

When the block copolymer b2 itself was used as a polymer electrolyte membrane, the ion exchange capacity obtained from the neutralization titration was 2.5 meq / g.

Synthesis example 5:
(Synthesis of ether sulfone (PES) -based block copolymer precursor b3'consisting of a segment represented by the following formula (G9) and a segment represented by the following formula (G10))
1.62 g of anhydrous nickel chloride and 15 mL of dimethyl sulfoxide were mixed and adjusted to 70 ° C. To this, 2.15 g of 2,2'-bipyridyl was added, and the mixture was stirred at the same temperature for 10 minutes to prepare a nickel-containing solution.

Here, 1.49 g of 2,5-dichlorobenzenesulfonic acid (2,2-dimethylpropyl) and Sumika Excel PES5200P (manufactured by Sumitomo Chemical Co., Ltd., Mn = 40,000, Mw = 94) represented by the following formula (G8). To a solution obtained by dissolving 0.50 g of 000) in 5 mL of dimethyl sulfoxide, 1.23 g of zinc powder was added to adjust the temperature to 70 ° C. The nickel-containing solution was poured into the solution, and a polymerization reaction was carried out at 70 ° C. for 4 hours. The reaction mixture was added to 60 mL of methanol, then 60 mL of 6 mol / L hydrochloric acid was added, and the mixture was stirred for 1 hour. The precipitated solid was separated by filtration and dried to obtain 1.62 g of a grayish white polyarylene containing the segments represented by the following formulas (G9) and the following formula (G10) in a yield of 99%. The weight average molecular weight was 200,000.

Synthesis Example 6: Synthesis of block copolymer b3 (Synthesis of PES-based block copolymer b3 consisting of a segment represented by the formula (G10) and a segment represented by the following formula (G11))
0.23 g of the block copolymer precursor b3 '20 obtained in Synthesis Example 5 is added to a mixed solution of 0.16 g of lithium bromide monohydrate and 8 mL of N-methyl-2-pyrrolidone, and reacted at 120 ° C. for 24 hours. I let you. The reaction mixture was poured into 80 mL of 6 mol / L hydrochloric acid and stirred for 1 hour. The precipitated solid was separated by filtration. The separated solid was dried to obtain a block copolymer b3 composed of a grayish white segment represented by the formula (G10) and a segment represented by the following formula (G11). The weight average molecular weight of the obtained polyarylene was 180,000.

When the block copolymer b3 itself was used as a polymer electrolyte membrane, the ion exchange capacity obtained from the neutralization titration was 2.0 meq / g.

[Example 1]
22 g of the block copolymer b1 obtained in Synthesis Example 1 was added to 80 g of NMP and stirred with a stirrer at 20,000 rpm for 3 minutes to obtain a transparent solution having a polymer concentration of 22% by mass. The solubility of the polymer was extremely good. The obtained solution is pressure-filtered using a glass fiber filter, cast-coated on a 250 μm PET roll substrate, dried at 150 ° C. for 20 minutes, heat-treated at 150 ° C. under nitrogen for 10 minutes, and rolled. A polyketal ketone film was obtained. It was immersed in a 10 wt% sulfuric acid aqueous solution at 95 ° C. for 24 hours for proton substitution and deprotection reaction, and then immersed in a large excess amount of pure water for 24 hours for thorough washing to obtain a polymer electrolyte membrane. The ion exchange capacity of the obtained electrolyte membrane was 2.1 meq / g, the film thickness was 25 μm, and the curl property was 40 mm. In addition, Table 1 shows the evaluation results of various physical properties of the electrolyte membrane.

Obtained an MEA was produced using the polymer electrolyte membrane was subjected to hydrogen compression evaluation. In the hydrogen compression evaluation, the cell voltage at 1 MPa was 0.3 V, showing excellent hydrogen compression capacity, and there was no film breakage even after compression .

[Example 2]
An electrolyte membrane was prepared by the same method as in Example 1 except that the film thickness was 50 μm and the thickness of the base material was 500 μm.

[Example 3]
An electrolyte membrane was prepared by the same method as in Example 1 except that the film thickness was 175 μm and the thickness of the base material was 1.2 mm.

[Comparative Example 1]
Various physical properties of a fluoroelectrolyte membrane NRE-221CS (thickness 25 μm) manufactured by DuPont Co., Ltd. were measured on the polymer electrolyte membrane. In the hydrogen compression evaluation, the voltage was not stable and some film breakage was observed after compression .

[Comparative Example 2]
Various physical properties of a fluoroelectrolyte membrane NR-212 (thickness 50 μm) manufactured by DuPont Co., Ltd. were measured on the polymer electrolyte membrane. In the hydrogen compression evaluation, the voltage was not stable and some film breakage was observed after compression .

[Comparative Example 3]
Various physical properties of a fluoroelectrolyte membrane N-117 (film thickness 175 μm) manufactured by DuPont Co., Ltd. were measured on the polymer electrolyte membrane.

[Comparative Example 4]
An electrolyte membrane was prepared by the same method as in Example 1 except that the film thickness was 30 μm and the thickness of the base material was 188 μm. The curl property was 92 mm, and linear scratches on the film surface during roll transfer were observed, so that it was difficult to measure the physical properties of the electrolyte membrane.

[Comparative Example 5]
An electrolyte membrane was prepared by the same method as in Example 1 except that the film thickness was 10 μm and the thickness of the base material was 100 μm. In the hydrogen compression evaluation, the voltage was not stable and some film breakage was observed after compression .

[Comparative Example 6]
An electrolyte membrane was prepared by the same method as in Example 1 except that the film thickness was 250 μm and the thickness of the base material was 2 mm. Proton conductivity is low and could not use as an electrolyte membrane for electrochemical hydrogen pump.

[Comparative Example 7]
An electrolyte membrane was prepared by the same method as in Example 2 except that the block copolymer b2 was used instead of the block copolymer b1. Tensile elongation at break is low, it did not use as an electrolyte membrane for electrochemical hydrogen pump.

[Comparative Example 8]
An electrolyte membrane was prepared by the same method as in Example 2 except that the block copolymer b3 was used instead of the block copolymer b1. Tensile elongation at break is low, it did not use as an electrolyte membrane for electrochemical hydrogen pump.

Claims (1)

Polymer electrolyte membrane precursor solution on a substrate by casting and coating a method for manufacturing a high-molecular electrolyte membrane that having a step of forming a polymer electrolyte membrane,
The polymer electrolyte membrane
A polymer electrolyte membrane for an electrochemical hydrogen pump made of an ionic group-containing aromatic hydrocarbon polymer:
Proton conductivity per unit area at 80 ° C. and 25% relative humidity is 0.12 S / cm ² or more;
Proton conductivity of 8 S / cm ² or more per unit area in an atmosphere of 80 ° C. and 90% relative humidity ;
Hydrogen permeability in an atmosphere of 80 ° C. and 90% relative humidity is 3.0 x ^10-7 cm ³ · (cm ² · s · cmHg) ^-1 or less;
The tensile breaking strength of a film having a width of 10 mm under an atmosphere of 25 ° C. and a relative humidity of 60% is 100,000 N or more;
Tensile breaking elongation is 150% or more;
The film thickness is 30 μm or more and 200 μm or less.
A method for producing a polymer electrolyte membrane for an electrochemical hydrogen pump, which comprises using a base material having a thickness satisfying the following (formula 1) as the base material.
7 ≦ T1 / T2 ≦ 15 (Equation 1)
(T1: Thickness of base material, T2: Thickness of polymer electrolyte membrane)