JP2007039536A - Ionic group-containing polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ionic group-containing polymer satisfying proton conductivity, fuel cutoff capability, swelling resistance to fuel and solubility of film-forming solvent all at high levels. <P>SOLUTION: The ionic group-containing polymer comprises an ionic group and a group represented by formula (A1) (T<SP>1</SP>is a secondary alkenyl group or a tertiary alkyl group). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polymer having an ionic group, and more particularly to a polymer having an ionic group excellent in proton conductivity.

  Polymers having an ionic group are used, for example, in medical material applications, filtration applications, concentration applications, ion exchange resin applications, various structural material applications, coating material applications, polymer actuators, electrochemical applications, and the like. In particular, as an electrochemical application, it is used as a polymer electrolyte material, a polymer electrolyte component or a membrane electrode assembly in a capacitor, a fuel cell, a redox flow battery, a water electrolysis device, a chloroalkali electrolysis device, and the like.

  Among these, the fuel cell is a power generation device that emits less, has high energy efficiency, and has a low burden on the environment. Fuel cells are also expected in the future as relatively small-scale distributed power generation facilities and mobile power generation devices such as automobiles and ships, and they are replaced by secondary batteries such as nickel metal hydride batteries and lithium ion batteries. In addition, it is expected to be mounted on small mobile devices such as mobile phones and personal computers by hybridizing with secondary batteries.

  In polymer electrolyte fuel cells (hereinafter sometimes referred to as PEFC), in addition to conventional PEFCs that use hydrogen gas as fuel, methanol and other fuels are reformed into hydrogen gas. Direct type fuel cells (direct methanol type fuel cells) that supply directly without doing so are also attracting attention. Although the direct fuel cell has a lower output than the conventional PEFC, the fuel is liquid and does not use a reformer, so the energy density is high and the power generation time per filling is long. is there.

  In general, in a fuel cell, an anode electrode and a cathode electrode in which a reaction responsible for power generation occurs and an electrolyte membrane serving as an ionic conductor between the anode and the cathode constitute a membrane-electrode complex (MEA), and this MEA is a separator. A cell sandwiched between the two is configured as a unit.

  In an anode electrode of a polymer electrolyte fuel cell, a fuel such as hydrogen gas reacts with a catalyst layer of the anode electrode to generate protons and electrons, the electrons are conducted to the electrode substrate, and the protons pass to the polymer solid electrolyte membrane. Conduct. For this reason, the anode electrode is required to have good gas diffusivity, electron conductivity and ion conductivity.

  On the other hand, in the cathode electrode, an oxidizing gas such as oxygen or air is generated in the catalyst layer of the cathode electrode by reacting protons conducted from the polymer solid electrolyte membrane and electrons conducted from the electrode substrate to produce water. . For this reason, in the cathode electrode, it is necessary to efficiently discharge the generated water together with gas diffusibility, electron conductivity and ion conductivity.

  In particular, among solid polymer fuel cells, in an electrolyte membrane for a direct fuel cell using an organic solvent such as methanol as a fuel, in addition to the performance required for an electrolyte membrane for a conventional PEFC using hydrogen gas as a fuel, In addition, swelling resistance to fuel methanol and permeation suppression of aqueous methanol solution are also required.

  For example, in an anode electrode of a direct type fuel cell, a fuel such as a methanol aqueous solution generates protons, electrons, and carbon dioxide by reaction of methanol and water in a catalyst layer. Electrons are conducted to the electrode substrate, protons are conducted to the polymer electrolyte, and carbon dioxide is released out of the system through the electrode substrate. Here, if methanol permeates through the polymer electrolyte membrane, a phenomenon called fuel crossover (MCO) or chemical short circuit occurs, which causes a serious problem that battery output and energy capacity are reduced.

  However, perfluoro proton conductive polymer membranes ("Nafion", trade name) manufactured by DuPont are conventionally used as polymer electrolyte membranes, such as methanol when used as polymer electrolyte membranes for direct fuel cells. There is a problem that the amount of fuel permeated is large and the battery output and energy capacity are remarkably reduced. Moreover, since the perfluoro proton conductive polymer is a fluorine polymer, its price is very high.

  Thus, a proton conductor polymer electrolyte made of a non-fluorine polymer is desired from the market, and some efforts have already been made for a polymer electrolyte membrane based on a non-fluorine polymer.

  For example, Non-Patent Documents 1 and 2 describe aromatic polyether polymer materials having an ionic group and having a phosphine oxide group in the main chain. A phenyl group is disclosed as a substituent on the phosphine oxide group.

  Patent Document 1 also describes an aromatic polyether polymer material having an ionic group, which has a phosphine oxide group in the main chain. Examples of the substituent on the phosphine oxide group include a methyl group, an isopropyl group, a cyclohexyl group, and a phenyl group. Further, the phenyl group or the methyl group is preferable in view of solubility in an organic solvent and easy synthesis of a high polymerization degree polymer. Groups are more preferred.

However, in these conventional techniques, one or more of proton conductivity, fuel barrier properties, swelling resistance to fuel, and solubility in a film forming solvent of the obtained polymer electrolyte material is not sufficient. It was required to satisfy all of these performances at a higher level.
Polymer Preprints, 41, 180 (2000) Polymer Preprints, 43, 342 (2002) JP 2004-269599 A

  An object of the present invention is to provide a polymer having an ionic group that satisfies all of proton conductivity, fuel barrier properties, swelling resistance to fuel, and solubility in a membrane-forming solvent at a high level.

  The polymer having an ionic group that achieves the above object is a polymer having an ionic group containing an ionic group and a group of the following formula (A1).

（式中、Ｔ^１は２級アルキル基又は３級アルキル基を表す。）

(In the formula, T ¹ represents a secondary alkyl group or a tertiary alkyl group.)

  Since the polymer having an ionic group of the present invention has an ionic group and a group having the specific structure of the formula (A1), proton conductivity, fuel blocking property, resistance to swelling to fuel, and film forming solvent. It has excellent characteristics satisfying all of the solubility at a high level.

  The polymer having an ionic group according to the present invention contains an ionic group and a group represented by the following formula (A1).

（式中、Ｔ^１は２級アルキル基又は３級アルキル基を表す。）

(In the formula, T ¹ represents a secondary alkyl group or a tertiary alkyl group.)

In the formula, T ¹ represents a secondary alkyl group or a tertiary alkyl group, but T ¹ may be a chain alkyl group or a cyclic alkyl group, and a secondary alkyl having 3 to 20 carbon atoms. And a tertiary alkyl group are preferred. T ¹ may be optionally substituted as long as it is a secondary alkyl group or a tertiary alkyl group. Preferable substituents for substituting T ¹ are alkyl groups, halogenated alkyl groups, phenyl groups, alkenyl groups, alkynyl groups, halogen groups, ionic groups and the like, and the number of substituents is preferably 0-10.

Preferable examples of T ¹ include isopropyl group, sec-butyl group, tert-butyl group, tert-pentyl group, hexane-2-yl group, heptan-2-yl group, and octan-2-yl group, 1-ethylpropyl, 1-methylisobutyl, 1-methylisopentyl, 1-methyloctyl, 1-ethyl-3-methylbutyl, 1,1-dimethylbutyl, 1,1-dimethylpentyl, 1,1-dimethylhexyl, Chain alkyl groups such as 1,1-dimethylheptyl, 1,1-dimethyloctyl, 1-ethyl-1-methylpropyl, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, Norbornyl group, adamantyl group, menthyl group, caryl group, norcalyl group, pinanyl group and the following formulas (T1-1) to (T1- And cyclic alkyl groups such as the group represented by 8), and those in which these cyclic alkyl groups are further substituted with a chain alkyl group.

  Among these, a cyclic alkyl group is more preferable, and in particular, a cyclic alkyl group having 7 to 20 carbon atoms is selected from proton conductivity, fuel blocking property, swelling resistance to fuel, and solubility in a film forming solvent. Furthermore, it is further preferable from the viewpoint of obtaining excellent characteristics.

  The group represented by the formula (A1) may be substituted with any number of substituents of any kind as long as the basic structure is not changed. Preferred substituents are an alkyl group, a halogenated alkyl group, an aryl group, a halogen group and an ionic group, and the preferred number of substituents is 0-8. By having such a substituent, the characteristics of solvent resistance and high proton conductivity can be obtained.

The ionic group of the polymer having an ionic group of the present invention is preferably a negatively charged atomic group, more preferably a proton exchange ability. As such a functional group, a sulfonic acid group (—SO ₂ (OH)), a sulfuric acid group (—OSO ₂ (OH)), a sulfonimide group (—SO ₂ NHSO ₂ R (R represents an organic group)). ), A phosphonic acid group (—PO (OH) ₂ ), a phosphoric acid group (—OPO (OH) ₂ ), a carboxylic acid group (—CO (OH)), and salts thereof can be preferably employed. Two or more kinds of these ionic groups may be contained in the polymer, and it may be preferable to combine two or more kinds. The combination is appropriately determined depending on the structure of the polymer. Among these, a sulfonic acid group, a sulfonimide group, and a sulfuric acid group are more preferable from the viewpoint of high proton conductivity, and a sulfonic acid group is most preferable from the viewpoint of hydrolysis resistance.

The polymer having an ionic group of the present invention preferably has a skeleton containing a repeating unit of the following formula (P1). This is because such a skeleton is excellent in hydrolysis resistance, and a tough polymer excellent in various mechanical properties can be obtained.
^{-Y 11 -Z 11 -Y 21 -Z 21} - (P1)
(Wherein Y ¹¹ and Y ²¹ each represent O or S. At least one of Z ¹¹ and Z ²¹ represents a group represented by the formula (A1), and Z ¹¹ is substituted. A divalent group containing a good aromatic ring is represented, and Z ²¹ represents a divalent group containing an aromatic ring having an electron-withdrawing group.
In the formula, Y ¹¹ and Y ²¹ each represent O or S, and more preferably O.

In the formula, at least one of Z ¹¹ and Z ²¹ represents a group represented by the formula (A1).

Z ¹¹ represents a divalent group containing an aromatic ring which may be substituted, and is excellent in all of proton conductivity, fuel blocking property, swelling resistance to fuel, and solubility in a film forming solvent. In terms of obtaining characteristics, preferred examples thereof include groups represented by the following formulas (Z1-1) to (Z1-12), groups represented by the following formulas (B1) to (B3), and the above formula ( Of these, any of the groups represented by A1), among which the groups represented by formulas (B1) to (B3) and the group represented by formula (A1) are particularly preferred.

（式中、Ｑ^１は、直接結合、メチレン基、カルボニル基、Ｏ又はＳを表し、Ｑ^２は、Ｈ、メチル基又はフェニル基を表し、Ｑ^３は、カルボニル基又はスルホニル基を表し、Ｑ^４は、Ｏ、Ｓ又はＮ−Ｒ^１を表す。Ｒ^１はＨ、アルキル基又はアリール基を表す。）

(Wherein Q ¹ represents a direct bond, a methylene group, a carbonyl group, O or S, Q ² represents H, a methyl group or a phenyl group, Q ³ represents a carbonyl group or a sulfonyl group, Q ^4, O, .R ¹ representing S or ^{N-R 1} represents H, an alkyl group or an aryl group.)

In formula (B1), Q ¹ represents a direct bond, a methylene group, a carbonyl group, O or S, and most preferably a direct bond.

In the formula (B2), Q ² represents H, an alkyl group, or an aryl group. Are preferably H, a methyl group or a phenyl group, and most preferably a phenyl group.

In formula (B3), Q ³ represents a carbonyl group or a sulfonyl group, preferably a carbonyl group. Q ⁴ represents O, S or N—R ¹ , preferably O and N—R ¹ , most preferably O. R ¹ represents H, an alkyl group or an aryl group, preferably H or an alkyl group having 1 to 3 carbon atoms.

  The groups represented by formulas (B1) to (B3) may be substituted with any number of substituents of any kind as long as the basic structure is not changed. Preferred substituents are an alkyl group having 1 to 3 carbon atoms, a phenyl group, a halogen group and an ionic group.

Further, in the above formula (P1), Z ²¹ represents a divalent group containing an aromatic ring having an electron withdrawing group, Z ²¹ may have an arbitrary substituent in addition to an electron-withdrawing group. Preferred substituents for Z ²¹ are an alkyl group, a halogenated alkyl group, an aryl group, a halogen group and an ionic group, and the preferred number of substituents is 1 to 9 including an electron-withdrawing group.

Z ²¹ is preferably a compound represented by the following formula (Z2) from the viewpoint of obtaining excellent properties in all of proton conductivity, fuel barrier properties, swelling resistance to fuel, and solubility in a film-forming solvent. -1) to (Z2-12) and a group represented by the formula (A1), and particularly preferred is a group represented by the formula (Z2-1), represented by the formula (Z2-2). A group and a group represented by formula (A1).

In the formula (P1), at least one of Z ¹¹ and Z ²¹ represents a group represented by the formula (A1). It is preferable that at least one of Z ¹¹ and Z ²¹ is a group represented by the formula (A1), which can exhibit characteristics excellent in proton conductivity and solubility in a film-forming solvent.

The polymer having an ionic group of the present invention preferably further has a skeleton containing a repeating unit of the following formula (P2).
^{-Y 12 -Z 12 -Y 22 -Z 22} - (P2)
[Wherein Y ¹² and Y ²² each represent O or S. Z ¹² represents a divalent group containing an optionally substituted aromatic ring, and Z ²² represents a group represented by the following formula (C1).

（式中、Ｑ^５は、カルボニル基又はスルホニル基を表し、Ｘは、Ｈ又は任意のカチオンを表す。）］

(In the formula, Q ⁵ represents a carbonyl group or a sulfonyl group, and X represents H or an arbitrary cation.)]

In the formula (P2), Y ¹² and Y ²² each represent O or S, and more preferably O.

In the formula (P2), Z ¹² represents a divalent group containing an optionally substituted aromatic ring, and preferred examples thereof are the same as the preferred examples of Z ¹¹ in the formula (P1).

In the formula (P2), Z ²² represents a group represented by the formula (C1).

In formula (C1), Q ⁵ represents a carbonyl group or a sulfonyl group, and has excellent properties in all of proton conductivity, fuel blocking property, swelling resistance to fuel, and solubility in a film forming solvent. From this viewpoint, a carbonyl group is more preferable. X represents H and any cation. Preferred optional cations include Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, and various ammoniums.

  The group of formula (C1) may be further optionally substituted, but those that are not substituted are most preferred.

In the present invention, the polymer having a skeleton containing the repeating unit of the formula (P1) can be obtained, for example, by the following method. That is, a compound represented by H—Y ¹¹ —Z ¹¹ —Y ²¹ —H (Y ¹¹ , Z ¹¹ and Y ²¹ have the same meanings as symbols in the formula (P1)) and / or a salt thereof , EZ ²¹ -E (Z ²¹ has the same meaning as that in the formula (P1). E represents F or Cl). Is the method. In the condensation polymerization, a deoxidizing agent such as potassium carbonate can be used as necessary. In addition, aprotic solvents such as diphenylsulfone, dimethylformamide, dimethylsulfoxide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethylimidazolidinone can be used. When water is generated during the condensation reaction, it is also preferable to add an azeotropic solvent such as toluene and remove the water by azeotropic distillation. The reaction temperature is about 100 to 300 ° C., and the reaction time is about 1 to 72 hours.

In addition to the repeating units of the formula (P1), further a method of producing a polymer having a backbone comprising repeating units of the formula (P2), the polymerization system further ^{H-Y 12 -Z 12 -Y 22} -H ( Y ¹² , Z ¹² and Y ²² have the same meanings as the symbols in the formula (P2).) And E-Z ²² -E (Z ²² represents the formula (P2 ) Is the same meaning as the symbol in E. E represents F or Cl.) By adding the aromatic halide compound represented by (4) and performing condensation polymerization at a high temperature, the above formulas (P1) and (P2) are repeated. A skeleton containing units is obtained.

  In the production of the polymer having an ionic group of the present invention, examples of the method for introducing an ionic group 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 a repeating unit may be used, and if necessary, an appropriate protecting group may be introduced to perform a deprotecting group after polymerization. . Such a method is described in, for example, Journal of Membrane Science, 197 (2002) 231-242. This method is very preferable because it can easily control the ion exchange capacity of the polymer and can be easily applied industrially.

  Next, the method for introducing an ionic group by a polymer reaction will be described with an example. For example, introduction of a phosphonic acid group into an aromatic polymer is described in Polymer Preprints, Japan, 51, 750 (2002), etc. This is possible by the method described. Introduction of a phosphate group into an aromatic polymer can be achieved by, for example, phosphoric esterification of an aromatic polymer having a hydroxyl group. Introduction of a carboxylic acid group into an aromatic polymer can be performed by oxidizing an aromatic polymer having an alkyl group or a hydroxyalkyl group, for example. Introduction of a sulfate group into an aromatic polymer can be achieved by, for example, sulfate esterification of an aromatic polymer having a hydroxyl group. As a method for sulfonating an aromatic polymer, that is, a method for introducing a sulfonic acid group, for example, a method described in JP-A-2-16126 or JP-A-2-208322 is known. Specifically, for example, an aromatic polymer can be sulfonated by reacting with a sulfonating agent such as chlorosulfonic acid in a solvent such as chloroform, or by reacting in concentrated sulfuric acid or fuming sulfuric acid. . The sulfonating agent is not particularly limited as long as it sulfonates an aromatic polymer, and sulfur trioxide or the like can be used in addition to the above. When the aromatic polymer is sulfonated by this method, the degree of sulfonation can be easily controlled by the use amount of the sulfonating agent, the reaction temperature and the reaction time. Introduction of a sulfonimide group into an aromatic polymer can be achieved, for example, by a method of reacting a sulfonic acid group and a sulfonamide group.

  The content of the ionic group of the polymer having an ionic group of the present invention can be represented by an ion exchange capacity. The ion exchange capacity of the polymer having an ionic group of the present invention is preferably 0.01 to 3.5 meq / g, more preferably 0.1 to 3.5 in terms of proton conductivity and resistance to swelling to fuel. ~ 2.5 meq / g. When the ion exchange capacity is lower than 0.01 meq / g, the output performance may be lowered due to low conductivity. When the ion exchange capacity is higher than 3.5 meq / g, sufficient fuel is required when used as a polymer electrolyte membrane. The swelling resistance and mechanical strength at the time of water content may not be obtained.

  In a polymer having an ionic group, when the content of the ionic group is increased in order to enhance proton conductivity, the polymer is swelled or dissolved in a fuel such as an alcohol aqueous solution. On the other hand, a polymer with small swelling with respect to fuel is generally poorly soluble in a solvent and tends to be inferior in film forming property.

On the other hand, the polymer having an ionic group according to the present invention has an ionic group and a group having a specific structure represented by the formula (A1). And has excellent resistance to swelling in fuel. (Transcribed from the manuscript draft on page 12, lines 17-23.)
In the present invention, the ion exchange capacity is the molar amount of ionic groups introduced per unit gram of the polymer having dry ionic groups. In the present invention, the ion exchange capacity is specified by titration.

When the ionic group is a sulfonic acid group, the titration procedure is as follows. The measurement shall be performed three times or more and the average shall be taken. A known titration method can be applied to ionic groups other than sulfonic acid groups.
(1) The sample is pulverized by a mill, and in order to make the particle size uniform, the sample is passed through a 50-mesh mesh sieve and the sample passed through the sieve is used as the measurement sample.
(2) Weigh the sample tube (with lid) with a precision balance.
(3) About 0.1 g of the sample of (1) is put in a sample tube and vacuum dried at a temperature of 40 ° C. for 16 hours.
(4) The sample tube containing the sample is weighed to determine the dry weight of the sample.
(5) Sodium chloride is dissolved in a 30 wt% aqueous methanol solution to prepare a saturated saline solution.
(6) Add 25 mL of the saturated salt solution of (5) above to the sample, and stir for 24 hours for ion exchange.
(7) The resulting hydrochloric acid is titrated with a 0.02 mol / L aqueous sodium hydroxide solution. Two drops of a commercially available phenolphthalein solution for titration (0.1% by volume) as an indicator are added, and the point at which light reddish purple is obtained is taken as the end point.
(8) The ion exchange capacity is determined by the following equation.

Ion exchange capacity (meq / g) =
[Concentration of sodium hydroxide aqueous solution (mmol / ml) × Drip amount (ml)] / Dry weight of sample (g)

  The polymer having an ionic group of the present invention contains other components, for example, an inactive polymer or an organic or inorganic compound having no conductivity or ionic conductivity, as long as the object of the present invention is not impaired. It does not matter.

  The molecular weight of the polymer having an ionic group of the present invention is preferably 10,000 or more, more preferably 20,000 or more in terms of weight average molecular weight. If the molecular weight is too small, the swelling resistance to fuel tends to decrease, which is not preferable. On the other hand, if the molecular weight is too large, the solubility in a solvent is decreased, which is not preferable. Therefore, the molecular weight is preferably 5000000 or less, more preferably 2000000 or less, and even more preferably 1000000 or less.

  The weight average molecular weight of the polymer of the present invention is measured by GPC. Specifically, an N-methyl-2-pyrrolidone solvent (containing 10 mmol / L of lithium bromide) was used, using an integrated GPC of an ultraviolet detector and a differential refractometer and two GPC columns having an inner diameter of 6.0 mm and a length of 15 cm. The N-methyl-2-pyrrolidone solvent used is measured at a flow rate of 0.2 mL / min, and the weight average molecular weight is determined in terms of standard polystyrene.

  The polymer having an ionic group of the present invention is preferably used for electrochemical applications as a polymer electrolyte material or a polymer electrolyte component. Preferred examples of the polymer electrolyte component include a polymer electrolyte membrane and an electrode catalyst layer.

  A production method in the case where the polymer having an ionic group of the present invention is applied to a polymer electrolyte membrane as a polymer electrolyte material will be described. As a method of forming a polymer electrolyte membrane from a polymer electrolyte material, a polymer electrolyte material made of a polymer having an ionic group is used as a solution, suspension or emulsion, and the solution has a desired film thickness. And a method of forming a film by removing the solvent by heating after coating, that is, a solvent casting method.

  The solid concentration of the liquid is preferably 1 to 50% by weight, more preferably 5 to 30% by weight, and particularly preferably about 10% by weight.

  As the coating method, methods such as spray coating, brush coating, dip coating, die coating, curtain coating, flow coating, spin coating, and screen printing can be applied.

  The solvent used for film formation is not particularly limited as long as the polymer electrolyte material can be dissolved and then removed. For example, N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone , Dimethyl sulfoxide, sulfolane, aprotic polar solvents such as 1,3-dimethyl-2-imidazolidinone and hexamethylphosphontriamide, ester solvents such as γ-butyrolactone and butyl acetate, carbonates such as ethylene carbonate and propylene carbonate Solvent, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, alkylene glycol monoalkyl ether such as propylene glycol monoethyl ether, or isopropanol Alcohol solvents, water and mixtures thereof is preferably used, is preferred for high highest solubility aprotic polar solvent.

  Next, the obtained polymer electrolyte membrane is preferably subjected to a heat treatment after at least a part of the ionic group is in a metal salt state. The metal of the metal salt may be any metal that can form a salt with sulfonic acid, but Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, W, and the like are preferable. Among these, Li, Na, K, Ca, Sr, and Ba are more preferable, and Li, Na, and K are more preferable.

  The temperature of this heat treatment is preferably 150 to 550 ° C, more preferably 160 to 400 ° C, and particularly preferably 180 to 350 ° C. If the heat treatment temperature is too low, the effect of suppressing fuel permeability tends to be insufficient. On the other hand, if the heat treatment temperature is too high, the membrane material tends to be deteriorated.

  The heat treatment time is preferably 10 seconds to 12 hours, more preferably 30 seconds to 6 hours, and particularly preferably 3 minutes to 2 hours. If the heat treatment time is less than 10 seconds, the effect of suppressing the fuel permeability tends to be insufficient. On the other hand, if it exceeds 12 hours, the membrane material tends to be deteriorated, which is not preferable.

  The heat-treated polymer electrolyte membrane can be proton-substituted by immersing it in an acidic aqueous solution as necessary. By forming by this method, the polymer electrolyte membrane of the present invention can achieve both a good balance between proton conductivity and fuel cutoff.

  In the polymer electrolyte membrane of the present invention, it is also preferable to crosslink the polymer structure by means such as radiation irradiation as necessary. By crosslinking such a polymer electrolyte membrane, an effect of further suppressing fuel crossover and swelling with respect to fuel can be expected, and mechanical strength may be improved, which may be more preferable. Examples of such radiation irradiation include electron beam irradiation and γ-ray irradiation.

  The thickness of the polymer electrolyte membrane of the present invention is preferably in the range of 1 to 2000 μm. A thickness of more than 1 μm is preferable to obtain a membrane strength that can withstand practical use, and a thickness of less than 2000 μm is preferable to reduce membrane resistance, that is, to improve power generation performance. A more preferable range of the film thickness is 3 to 500 μm, and a particularly preferable range is 5 to 250 μm. The film thickness can be controlled by the solution concentration or the coating thickness on the substrate. The film thickness of the polymer electrolyte membrane can be measured with a contact-type film thickness meter.

  In addition, an additive such as a plasticizer, a stabilizer, or a mold release agent used for a general polymer compound may be added to the polymer electrolyte material of the present invention within a range not contrary to the object of the present invention. it can.

  In addition, the polymer electrolyte material of the present invention contains the ionic group of the present invention for the purpose of improving mechanical strength, thermal stability, workability and the like within a range that does not adversely affect the above-mentioned various properties. You may contain various polymers other than the polymer which has, an elastomer, a filler, microparticles | fine-particles, various additives, etc.

The polymer electrolyte membrane of the present invention preferably has a methanol permeation amount per unit area of 40 μmol · min ⁻¹ · cm ⁻² or less with respect to a 30 wt% aqueous methanol solution at a temperature of 20 ° C. This is because in a fuel cell using the polymer electrolyte membrane, it is desired that the amount of fuel permeation is small in order to maintain a high fuel concentration from the viewpoint of obtaining a high output and a high energy capacity in a high fuel concentration region. .

The methanol permeation amount of the polymer electrolyte membrane is most preferably ⁰ μmol · min ⁻¹ · cm ⁻² from this viewpoint, but from the viewpoint of ensuring proton conductivity, 0.01 μmol · min ⁻¹ · cm ⁻² or more preferable.

  The methanol permeation amount of the polymer electrolyte membrane is a value determined by the following measurement method.

First, a polymer electrolyte membrane sample was immersed in pure water at 25 ° C. for 24 hours, and then the polymer electrolyte membrane sample was sandwiched between H-type cells, and pure water (60 mL) was placed in one cell, The cell is charged with 30% by weight aqueous methanol solution (60 mL) and both cells are stirred at a temperature of 20 ° C. In addition, the capacity | capacitance of a cell is 80 mL each, and the opening part area between cells is 1.77 cm < ² >. The amount of methanol eluted in pure water after 1 hour, 2 hours and 3 hours has been quantitatively measured with a gas chromatography (GC-2010) manufactured by Shimadzu Corporation, and the methanol permeation amount per unit time is obtained from the slope of the graph. is there.

The polymer electrolyte membrane of the present invention preferably has proton conductivity per unit area is 1S · ^{cm -2} or more, 2S · ^{cm -2} or more is more preferable. By setting the proton conductivity per unit area to 1 S · cm ⁻² or more, when used as a polymer electrolyte membrane for a fuel cell, sufficient proton conductivity, that is, sufficient battery output can be obtained. Higher proton conductivity is preferable, but a membrane with high proton conductivity tends to be dissolved or disintegrated by a fuel such as an aqueous methanol solution, and the fuel permeation amount tends to increase. Therefore, a practical upper limit is 50 S · cm. ^-2 .

  The proton conductivity was determined by immersing the polymer electrolyte membrane in a 30 wt% aqueous methanol solution (at least 1000 times the sample amount by weight) at 25 ° C. for 12 hours, and then pure water (sample amount by weight) at 20 ° C. After being immersed for 24 hours or more with stirring in the mixture at a temperature of 1000 times or more, the proton conductivity is measured by a constant potential alternating current impedance method as quickly as possible.

The proton conductivity measurement apparatus uses a Solartron electrochemical measurement system, and the sample is sandwiched between two circular electrodes (made of stainless steel) of φ2 mm and φ10 mm with a weight of 1 kg, and the effective electrode area is 0.0314 cm. ² . A 15% by weight aqueous solution of poly (2-acrylamido-2-methylpropanesulfonic acid) is applied to the interface between the sample and the electrode. A constant potential impedance measurement with an AC amplitude of 50 mV is performed at a temperature of 25 ° C., and proton conductivity in the film thickness direction is obtained. The value is the proton conductivity per unit area.

  The polymer electrolyte membrane of the present invention can achieve the low methanol permeation amount and the high proton conductivity as described above, and is preferable from the viewpoint of achieving both high output and high energy capacity.

  Next, the case where the polymer having an ionic group according to the present invention is applied to an electrode catalyst layer as another example of a polymer electrolyte component composed of a polymer electrolyte material will be described.

  The electrode catalyst layer is a layer containing an electrode catalyst that promotes an electrode reaction, an electron conductor, an ion conductor, and the like. As the electrode catalyst contained in the electrode catalyst layer, for example, a noble metal catalyst such as platinum, palladium, ruthenium, rhodium, iridium and gold is preferably used. One of these may be used alone, or two or more of them, such as alloys and mixtures, may be used in combination.

  As the electron conductor (conductive material) contained in the electrode catalyst layer, a carbon material or an inorganic conductive material is preferably used from the viewpoint of electronic conductivity and chemical stability. Among these, amorphous and crystalline carbon materials are mentioned. For example, carbon black such as channel black, thermal black, furnace black, and acetylene black is preferably used because of its electron conductivity and specific surface area. Furnace Black includes “Vulcan XC-72” (R), “Vulcan P” (R), “Black Pearls 880” (R), “Black Pearls 1100” (R), “Black Pearls 1300” R), “Black Pearls 2000” (R), “Legal 400” (R), “Ketjen Black” (R) EC, EC600JD, Mitsubishi Chemical Corporation # 3150, # 3250, etc. Examples of acetylene black include “DENKA BLACK” (R) manufactured by Denki Kagaku Kogyo Co., Ltd.

  In addition to carbon black, artificial graphite or carbon obtained from organic compounds such as natural graphite, pitch, coke, polyacrylonitrile, phenol resin, and furan resin can also be used. As the form of these carbon materials, in addition to irregular particles, fibers, scales, tubes, cones, and megaphones can also be used. Moreover, you may use what post-processed these carbon materials.

  Moreover, it is preferable in terms of electrode performance that the electron conductor is uniformly dispersed with the catalyst particles. For this reason, it is preferable that the catalyst particles and the electron conductor are well dispersed in advance as a coating liquid.

  Furthermore, it is also a preferred embodiment that catalyst-supporting carbon in which the catalyst and the electron conductor are integrated is used as the electrode catalyst layer. By using this catalyst-supporting carbon, the utilization efficiency of the catalyst is improved, and it can contribute to the improvement of battery performance and cost reduction. Here, even when catalyst-supported carbon is used for the electrode catalyst layer, a conductive agent can be added to further increase the electron conductivity. As such a conductive agent, the above-described carbon black is preferably used.

  In general, various organic and inorganic materials are known as substances having ion conductivity (ion conductor) used in such an electrode catalyst layer. However, when used in a fuel cell, the ion conductivity is improved. A polymer having an ionic group such as a sulfonic acid group, a carboxylic acid group, or a phosphoric acid group (ion conductive polymer) is preferably used. Among these, from the viewpoint of stability of the ionic group, a polymer having ionic conductivity composed of a fluoroalkyl ether side chain and a fluoroalkyl main chain, or a polymer having the ionic group of the present invention is preferably used.

  As the perfluoro-based ion conductive polymer, for example, “Nafion” (R) manufactured by DuPont, “Aciplex” (R) manufactured by Asahi Kasei Corporation, “Flemion” (R) manufactured by Asahi Glass Co., Ltd. and the like are preferably used. These ion conductive polymers are provided in the electrode catalyst layer in the state of a solution or a dispersion. At this time, the solvent for dissolving or dispersing the polymer is not particularly limited, but a polar solvent is preferable from the viewpoint of the solubility of the ion conductive polymer.

  In the electrode catalyst layer, since the catalyst and the electronic conductors are usually powders, the ionic conductor usually plays a role of hardening them. It is preferable from the viewpoint of electrode performance that the ionic conductor is added in advance to a coating liquid mainly composed of electrode catalyst particles and an electron conductor when the electrode catalyst layer is produced, and is applied in a uniformly dispersed state. However, the ion conductor may be applied after the electrode catalyst layer is applied. Here, examples of the method for applying the ion conductor to the electrode catalyst layer include spray coating, brush coating, dip coating, die coating, curtain coating, and flow coating, and are not particularly limited.

  The amount of the ion conductor contained in the electrode catalyst layer should be appropriately determined according to the required electrode characteristics and the conductivity of the ion conductor used, and is not particularly limited. The range of 1 to 80% is preferable, and the range of 5 to 50% is more preferable. When the ion conductor is too small, the ion conductivity is low, and when it is too much, the gas permeability may be hindered.

  Such an electrode catalyst layer may contain various substances in addition to the catalyst, the electronic conductor, and the ionic conductor. In particular, in order to improve the binding property of the substance contained in the electrode catalyst layer, a polymer other than the ion conductive polymer described above may be included. Examples of such a polymer include fluorine atoms such as polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polyhexafluoropropylene (FEP), polytetrafluoroethylene, and polyperfluoroalkyl vinyl ether (PFA). These copolymers, copolymers of monomer units constituting these polymers and other monomers such as ethylene and styrene, or blend polymers can be used. The content of these polymers in the electrode catalyst layer is preferably in the range of 5 to 40% by weight. When there is too much polymer content, there exists a tendency for electronic and ionic resistance to increase and for electrode performance to fall.

  In addition, when the fuel is a liquid or gas, the electrode catalyst layer preferably has a structure that allows the liquid or gas to permeate, and preferably has a structure that promotes the discharge of by-products due to the electrode reaction. .

  The membrane electrode assembly (MEA) of the present invention is constituted using a polymer electrolyte component such as the polymer electrolyte membrane and / or electrode catalyst layer of the present invention.

  In addition to the above, an electrode substrate can be used for the membrane electrode assembly (MEA). As the electrode base material, one having a low electric resistance and capable of collecting or feeding power can be used. Moreover, when using the said electrode catalyst layer also as a collector, it is not necessary to use an electrode base material in particular. The constituent material of the electrode base material is preferably a carbonaceous material and a conductive inorganic material. For example, a fired body from polyacrylonitrile, a fired body from pitch, a carbon material such as graphite and expanded graphite, stainless steel, molybdenum And titanium.

  These forms are not particularly limited, and are used, for example, in the form of fibers or particles. From the viewpoint of fuel permeability, fibrous conductive materials (conductive fibers) such as carbon fibers are preferable. As an electrode base material using conductive fibers, either a woven fabric or a non-woven fabric structure can be used. For example, carbon paper TGP series, SO series manufactured by Toray Industries, Inc., carbon cloth manufactured by E-TEK, etc. are used.

  As the woven fabric, a plain weave, a twill weave, a satin weave, a crest weave, a binding weave and the like are used without particular limitation. Moreover, as a nonwoven fabric, it does not specifically limit, such as a paper making method, a needle punch method, a spun bond method, a water jet punch method, and a melt blow method. It may also be a knitted fabric. In particular, when carbon fibers are used in these fabrics, carbonized plain fabric using flame-resistant spun yarn is carbonized or graphitized, and flame-resistant yarn is carbonized after being processed into a nonwoven fabric by the needle punch method or water jet punch method. Alternatively, a graphitized nonwoven fabric, a flameproof yarn, a carbonized yarn, or a mat nonwoven fabric by a paper making method using a graphitized yarn is preferably used. In particular, it is preferable to use a non-woven fabric because a thin and strong fabric can be obtained.

  When conductive fibers made of carbon fibers are used for the electrode substrate, examples of the carbon fibers include polyacrylonitrile (PAN) -based carbon fibers, phenol-based carbon fibers, pitch-based carbon fibers, and rayon-based carbon fibers.

  In addition, the electrode base material has a water repellent treatment for preventing gas diffusion / permeability deterioration due to water retention, a partial water repellent treatment for forming a water discharge path, a hydrophilic treatment, and a resistor for reducing resistance. Carbon powder can be added.

  In the polymer electrolyte fuel cell of the present invention, it is preferable to provide a conductive intermediate layer containing at least an inorganic conductive material and a hydrophobic polymer between the electrode substrate and the electrode catalyst layer. In particular, when the electrode base material is a carbon fiber woven fabric or a nonwoven fabric having a large porosity, by providing the conductive intermediate layer, it is possible to suppress performance degradation due to the electrode catalyst layer permeating into the electrode base material.

  A method for producing a membrane electrode assembly (MEA) using a polymer electrolyte membrane and an electrode catalyst layer or an electrode catalyst layer and an electrode substrate is not particularly limited. Known methods (for example, the chemical plating method described in “Electrochemistry” 1985, 53, 269. “J. Electrochem. Soc.”: Electrochemical Science and Technology, 1988, 135 (9), 2209 It is possible to apply the gas diffusion electrode hot press bonding method described above. Although integration by hot pressing is a preferred method, the temperature and pressure may be appropriately selected depending on the thickness of the polymer electrolyte membrane, the moisture content, the electrode catalyst layer, and the electrode substrate. Alternatively, the polymer electrolyte membrane may be pressed in a water-containing state, or may be bonded with a polymer having ion conductivity.

  Examples of the fuel for the polymer electrolyte fuel cell of the present invention include hydrogen, methane, ethane, propane, butane, methanol, isopropyl alcohol, acetone, ethylene glycol, diethylene glycol, formic acid, acetic acid, dimethyl ether, diethyl ether, diisopropyl ether, hydroquinone, Examples include organic compounds such as cyclohexane and ascorbic acid, and mixtures of these with water. As the fuel of the direct fuel cell that directly supplies liquid fuel, in particular, from the viewpoint of power generation efficiency and simplification of the entire cell system, among these, organic compounds having 1 to 6 carbon atoms and mixtures of these with water are preferable. 1 type or 2 or more types of mixtures may be sufficient. Particularly preferred from the viewpoint of power generation efficiency is methanol or an aqueous methanol solution.

  The content of the organic compound having an alkyl group or alkylene group having 1 to 6 carbon atoms in the fuel supplied to the membrane electrode assembly is preferably 20 to 70% by weight. When the content is less than 20% by weight, it is difficult to obtain a practical high energy capacity. When the content exceeds 70% by weight, the balance between power generation efficiency and output tends to be lost, and high power generation efficiency and high output are satisfied at the same time. It is difficult to get practical things to do.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, the scope of the present invention is not limited by these Examples.

[Measuring method]
The measurement method employed in the examples will be described below.

(1) Weight average molecular weight The weight average molecular weight of the polymer was measured by GPC. Tosoh HLC-8022GPC is used as an integrated UV detector and differential refractometer, and Tosoh TSK gel SuperHM-H (inner diameter 6.0 mm, length 15 cm) is used as the GPC column. -2-Pyrrolidone solvent (Measured with a N-methyl-2-pyrrolidone solvent containing 10 mmol / L of lithium bromide at a flow rate of 0.2 mL / min, and the weight average molecular weight was determined in terms of standard polystyrene.

(2) Film thickness It measured with the contact-type film thickness meter.

(3) Proton conductivity A sample of the polymer electrolyte membrane was immersed in a 30% aqueous methanol solution (at least 1000 times the sample amount by weight) at 25 ° C. for 12 hours, and then pure water (by weight) at 20 ° C. The sample was immersed for 24 hours or longer with stirring in a sample amount of 1000 times or more) and then taken out into an atmosphere at 25 ° C. and a relative humidity of 50 to 80%, and the proton conductivity was measured by the constant potential alternating current impedance method as quickly as possible.

As a measuring apparatus, a Solartron electrochemical measurement system (Solartron 1287 Electrochemical Interface and Solartron 1255B Frequency Response Analyzer) was used. The sample was sandwiched between two circular electrodes (made of stainless steel) of φ2 mm and φ10 mm with a weight of 1 kg. The effective electrode area is 0.0314 cm ² . A 15% aqueous solution of poly (2-acrylamido-2-methylpropanesulfonic acid) was applied to the interface between the sample and the electrode. At 25 ° C., a constant potential impedance measurement with an AC amplitude of 50 mV was performed to determine proton conductivity in the film thickness direction. The value was expressed in terms of unit area.

(4) Methanol permeation amount (MCO)
A sample of the polymer electrolyte membrane was immersed in pure water at 25 ° C. for 24 hours, and then measured at 20 ° C. A sample was sandwiched between the H-type cells, pure water (60 mL) was placed in one cell, and 30 wt% aqueous methanol solution (60 mL) was placed in the other cell. The cell capacity was 80 mL each. Moreover, the opening area between cells was 1.77 cm < ² >. Both cells were stirred at 20 ° C. The amount of methanol eluted in pure water at the time of 1 hour, 2 hours and 3 hours was measured and quantified with a gas chromatography (GC-2010) manufactured by Shimadzu Corporation. The methanol permeation amount per unit time was determined from the slope of the graph.

(5) Evaluation of membrane electrode assembly and polymer electrolyte fuel cell MEA evaluation was performed by setting the membrane electrode assembly (MEA) in a cell manufactured by Electrochem, and flowing 30% methanol aqueous solution on the anode side and air on the cathode side. Went. In the evaluation, a constant current was passed through the MEA, and the voltage at that time was measured. The measurement was performed until the current was increased successively until the voltage became 10 mV or less. The product of current and voltage at each measurement point is output, and the maximum value (per unit area of MEA) is defined as output (mW / cm ² ).

  The energy capacity was calculated by the following formula (Equation 1) based on the output and the MCO at the MEA.

エネルギー容量：Ｗｈ
出力：最大出力密度（ｍＷ／ｃｍ^２）
容積：燃料の容積（本実施例では１０ｍＬとして計算した。）
濃度：燃料のメタノール濃度（％）
ＭＣＯ：ＭＥＡでのＭＣＯ（μｍｏｌ・ｍｉｎ^−１・ｃｍ^−２）
電流密度：最大出力密度が得られるときの電流密度（ｍＡ／ｃｍ^２）

Energy capacity: Wh
Output: Maximum output density (mW / cm ² )
Volume: Volume of fuel (calculated as 10 mL in this example)
Concentration: Fuel methanol concentration (%)
MCO: MCO at MEA (μmol · min ⁻¹ · cm ⁻² )
Current density: Current density when the maximum output density is obtained (mA / cm ² )

  In the MCO in the MEA, exhaust gas from the cathode was sampled by a collecting tube. This was evaluated using a total organic carbon meter TOC-VCSH (a measuring instrument manufactured by Shimadzu Corporation) or a MeOH permeation measuring device Micro GC CP-4900 (a gas chromatograph manufactured by GL Sciences Inc.). The MCO was calculated by measuring the total of MeOH and carbon dioxide in the sampling gas.

(6) Evaluation of solubility of polymer having ionic group in film-forming solvent Sample polymer was dissolved in N-methyl-2-pyrrolidone so as to be a 20 wt% solution, and the dissolution state at this time was visually observed. Observed and evaluated according to the following criteria.
◎: Easily completely dissolved, dissolved state is good ○: Completely dissolved, dissolved state is good △: There is a little undissolved residue, dissolved state is slightly poor ×: Insoluble content is a lot, poor dissolved state

(7) Evaluation of swelling resistance of polymer electrolyte membrane to fuel The polymer electrolyte membrane was immersed in a 60% methanol aqueous solution at a temperature of 60 ° C. for 10 hours, visually observed, and the swelling state was evaluated according to the following criteria. .
○: Swelling is small and swelling resistance is good Δ: Swelling is slightly large and swelling resistance is slightly poor ×: Swelling is large and swelling resistance is poor

Synthesis example 1

109.1 g of 4,4′-difluorobenzophenone was reacted in 150 mL of fuming sulfuric acid (50% SO ₃ ) at a temperature of 100 ° C. for 10 hours. Thereafter, the mixture was poured little by little into a large amount of water, neutralized with NaOH, and 200 g of sodium chloride was added to precipitate the composite. The resulting precipitate was filtered off and recrystallized with an aqueous ethanol solution to obtain the compound represented by the above formula (m1).

Synthesis example 2

  A compound represented by the above formula (m2) was obtained in the same manner as in Synthesis Example 1 except that bis (4-chlorophenyl) sulfone was used in place of 4,4'-difluorobenzophenone.

Synthesis example 3

  Under inert gas, magnesium (7.0 g) was added to a 500 ml three-necked eggplant flask, tetrahydrofuran (225 ml) was added to iodine (two pieces), and the mixture was stirred at room temperature until colorless. Next, a tetrahydrofuran (225 ml) solution of 1-bromo-4-fluorobenzene (31.5 ml) was added dropwise over 3.5 hours, and the mixture was heated to reflux for 5 hours after the completion of the addition.

  Next, a solution of 2-norbornylphosphonic dichloride (22.7 ml) in tetrahydrofuran (25 ml) was added dropwise over 2 hours, and the mixture was heated to reflux for 24 hours after completion of the addition.

  The reaction was stopped with a saturated aqueous ammonium chloride solution (300 ml), the organic layer was separated, the aqueous layer was extracted with methylene chloride (2 × 100 ml), and the organic layer was dried over anhydrous magnesium sulfate.

  After filtration, the solvent was distilled off, and recrystallization was performed from ethanol-petroleum ether to obtain a compound represented by the above formula (m3) (white crystals).

Synthesis example 4

  In the same manner as in Synthesis Example 3 except that 2-adamantylphosphonic dichloride (27.0 ml) was used instead of 2-norbornylphosphonic dichloride (22.7 ml), the compound represented by the above formula (m4) was prepared. Obtained.

Synthesis example 5

  A compound represented by the above formula (m5) was obtained in the same manner as in Synthesis Example 3, except that isopropylphosphonic dichloride (17.2 ml) was used instead of 2-norbornylphosphonic dichloride (22.7 ml). .

Synthesis Example 6

  Under inert gas, magnesium (1.95 g) was added to a 500 ml three-neck eggplant flask, and THF (65 ml) was added to iodine (4 mg), followed by stirring at room temperature until colorless. Next, 4-bromoanisole (10 ml) was added dropwise over 1 hour, and after completion of the addition, the mixture was heated to reflux for 7 hours.

  Next, a solution of 2-norbornylphosphonic dichloride (6.33 ml) in THF (10 ml) was added dropwise over 1 hour, and after completion of the addition, the mixture was heated to reflux for 24 hours.

The reaction was stopped with a saturated aqueous ammonium chloride solution (250 ml), the organic layer was separated, the aqueous layer was extracted with methylene chloride (2 × 100 ml), and the organic layer was dried over anhydrous magnesium sulfate.
After filtration, the solvent was distilled off, and recrystallization was performed from petroleum ether to obtain bis (4-methoxyphenyl) -2-norbornylphosphine oxide (white crystals).

  Next, hydrobromic acid (40 ml), acetic acid (40 ml), bis (4-methoxyphenyl) -2-norbornylphosphine oxide (10.13 g) were placed in a 200 ml three-necked eggplant flask equipped with a calcium chloride tube. The mixture was heated to reflux at 125 ° C. for 60 hours.

  After cooling to room temperature, distilled water (300 ml) was slowly added dropwise and stirred for 1 hour. The precipitated crystals were separated by filtration, dissolved in ethanol, activated carbon was added, and suction filtration was performed. The solvent was distilled off, and recrystallization from toluene was performed to obtain the compound represented by the above formula (m6) (pale red crystals).

Comparative Example 1
A commercially available “Nafion” 117 membrane (trade name, manufactured by DuPont) was used to evaluate proton conductivity and methanol permeation. The Nafion 117 membrane was immersed in 5% hydrogen peroxide water at 100 ° C. for 30 minutes and then in 5% dilute sulfuric acid at 100 ° C. for 30 minutes, and then thoroughly washed with deionized water at 100 ° C. The methanol permeation amount (MCO) was 5.9 μmol · min ⁻¹ · cm ⁻² , and the proton conductivity was 5.7 S · cm ⁻² .

Example 1
6.9 g of potassium carbonate, 14.0 g of bis (4-hydroxyphenyl) diphenylmethane, 6.8 g of the compound of the formula (m1) obtained in Synthesis Example 1 and 8.0 g of the compound of the formula (m3) obtained in Synthesis Example 3 The polymerization was carried out at 190 ° C. in N-methylpyrrolidone (NMP). During this time, toluene was added as appropriate and water was removed from the polymerization system by an azeotropic method. Purification was performed by reprecipitation with a large amount of water to obtain a polymer having an ionic group. The weight average molecular weight of the obtained polymer was 190,000.

  The obtained polymer was used as an N-methyl-2-pyrrolidone solution (20% by weight). The dissolution state at this time was visually evaluated by the above method.

  Thereafter, the solution was cast on a glass substrate and dried at 100 ° C. for 4 hours to remove the solvent. Furthermore, it heated up on 200-300 degreeC over 1 hour in nitrogen gas atmosphere, and heat-processed on the conditions heated at 300 degreeC for 10 minutes, Then, it stood to cool. After immersing in 1N hydrochloric acid for 3 days or more to perform proton substitution, the polymer electrolyte membrane was obtained by immersing in a large excess amount of pure water for 3 days or more and thoroughly washing.

The proton conductivity and methanol permeation amount (MCO) of the obtained polymer electrolyte membrane were evaluated by the above methods. Proton conductivity is a numerical value represented by S · cm ⁻² , MCO is a numerical value represented by μmol · min ⁻¹ · cm ⁻² , and each is a ratio (Nafion ratio) to the value of Comparative Example 1 Expressed in Further, as a value for evaluating the balance between proton conductivity and MCO, a value obtained by dividing MCO (Nafion ratio) by proton conductivity (Nafion ratio), that is, “MCO / proton conductivity” was obtained. The smaller this value, the better the balance between proton conductivity and MCO.

  The swelling resistance of the polymer electrolyte membrane with respect to a 60% aqueous methanol solution was evaluated by the above method.

  The evaluation results are shown in Table 1.

Example 2
A polymer having an ionic group was obtained in the same manner as in Example 1 except that 9,9-bis (4-hydroxyphenyl) fluorene was used instead of bis (4-hydroxyphenyl) diphenylmethane. The weight average molecular weight of the obtained polymer was 210,000.

  The obtained polymer was made into an N-methyl-2-pyrrolidone solution (20% by weight) in the same manner as in Example 1. The dissolution state at this time was visually evaluated, and then a film was formed in the same manner as in Example 1 to obtain a polymer electrolyte membrane. The obtained polymer electrolyte membrane was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2

  9,9-bis (4-hydroxyphenyl) fluorene was used in place of bis (4-hydroxyphenyl) diphenylmethane, and instead of 8.0 g of the compound of formula (m3) obtained in Synthesis Example 3, the above formula (n1) A polymer having an ionic group was obtained in the same manner as in Example 1 except that 7.5 g of the compound was used. The weight average molecular weight of the obtained polymer was 200,000.

  The obtained polymer was made into an N-methyl-2-pyrrolidone solution (20% by weight) in the same manner as in Example 1. The dissolution state at this time was visually evaluated, and then a film was formed in the same manner as in Example 1 to obtain a polymer electrolyte membrane. The obtained polymer electrolyte membrane was evaluated in the same manner as in Example 1. The results are shown in Table 1.

  The polymer obtained in Comparative Example 2 was inferior in solubility, and the polymer electrolyte membrane was inferior in the balance between proton conductivity and MCO.

Comparative Example 3

  Instead of bis (4-hydroxyphenyl) diphenylmethane, 9,9-bis (4-hydroxyphenyl) fluorene was used, and instead of 8.0 g of the compound of formula (m3) obtained in Synthesis Example 3, the above formula (n2) A polymer having an ionic group was obtained in the same manner as in Example 1 except that 6.1 g of the compound was used. The weight average molecular weight of the obtained polymer was 200,000.

  The obtained polymer was made into an N-methyl-2-pyrrolidone solution (20% by weight) in the same manner as in Example 1. The dissolution state at this time was visually evaluated, and then a film was formed in the same manner as in Example 1 to obtain a polymer electrolyte membrane. The obtained polymer electrolyte membrane was evaluated in the same manner as in Example 1. The results are shown in Table 1.

  The polymer obtained in Comparative Example 2 was inferior in solubility, and the polymer electrolyte membrane was inferior in proton conductivity and MCO balance and swelling resistance.

Example 3
In place of 14.0 g of bis (4-hydroxyphenyl) diphenylmethane, 12.7 g of phenolphthalein was used, and instead of 6.8 g of the compound of formula (m1) obtained in Synthesis Example 1, the formula (m2 ), And a polymer having an ionic group was obtained in the same manner as in Example 1 except that 8.9 g of the compound of formula (m3) obtained in Synthesis Example 3 was used. The weight average molecular weight of the obtained polymer was 240,000.

  The obtained polymer was made into an N-methyl-2-pyrrolidone solution (20% by weight) in the same manner as in Example 1. The dissolution state at this time was visually evaluated, and then a film was formed in the same manner as in Example 1 to obtain a polymer electrolyte membrane. The obtained polymer electrolyte membrane was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
In place of 14.0 g of bis (4-hydroxyphenyl) diphenylmethane, 7.0 g of bis (4-hydroxyphenyl) diphenylmethane and 3.7 g of 4,4′-dihydroxybiphenyl were used, and the formula (m3) obtained in Synthesis Example 3 was used. A polymer having an ionic group was obtained in the same manner as in Example 1 except that 6.7 g of the compound of the formula (m5) obtained in Synthesis Example 5 was used instead of 8.0 g of the above compound. The weight average molecular weight of the obtained polymer was 230,000.

  The obtained polymer was made into an N-methyl-2-pyrrolidone solution (20% by weight) in the same manner as in Example 1. The dissolution state at this time was visually evaluated, and then a film was formed in the same manner as in Example 1 to obtain a polymer electrolyte membrane. The obtained polymer electrolyte membrane was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5
Obtained in Synthesis Example 3 by using 7.0 g of bis (4-hydroxyphenyl) diphenylmethane and 6.6 g of the compound of the formula (m6) obtained in Synthesis Example 6 instead of 14.0 g of bis (4-hydroxyphenyl) diphenylmethane. A polymer having an ionic group was obtained in the same manner as in Example 1 except that 5.3 g of 4,4′-difluorobenzophenone was used instead of 8.0 g of the compound of the formula (m3). The weight average molecular weight of the obtained polymer was 250,000.

  The obtained polymer was made into an N-methyl-2-pyrrolidone solution (20% by weight) in the same manner as in Example 1. The dissolution state at this time was visually evaluated, and then a film was formed in the same manner as in Example 1 to obtain a polymer electrolyte membrane. The obtained polymer electrolyte membrane was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6
(1) Production of membrane electrode assembly (MEA) A carbon fiber cloth substrate was subjected to a water-repellent treatment using a 20% polytetrafluoroethylene (PTFE) suspension and baked to produce two electrode substrates. .

  On one electrode substrate, an anode electrode catalyst coating solution composed of Pt—Ru-supported carbon and an N-methyl-2-pyrrolidone solution of the polymer electrolyte material obtained in Example 1 was applied and dried. An anode electrode was prepared.

  On the other electrode substrate, a cathode electrode catalyst coating solution comprising Pt-supported carbon and a “Nafion” solution was applied and dried to prepare a cathode electrode.

The polymer electrolyte membrane obtained in Example 1 was held between an anode electrode and a cathode electrode, and heated and pressed to produce an MEA.
(2) Production of polymer electrolyte fuel cell The MEA obtained in (1) above is sandwiched between cells manufactured by Electrochem, and a 30 wt% aqueous methanol solution is flown on the anode side and air is flowed on the cathode side. It was.

The polymer electrolyte fuel cell using the polymer electrolyte membrane of this example showed an output of 24 mW / cm ² at a temperature of 20 ° C. The energy capacity was 2.5 Wh.

Example 7
The membrane electrode composite and the polymer electrolyte fuel cell were prepared by preparing a “Nafion” solution instead of the N-methyl-2-pyrrolidone solution of the polymer electrolyte material obtained in Example 1 in the preparation of the anode electrode catalyst coating solution. The same procedure as in Example 6 was performed except that. The output was 25 mW / cm ² and the energy capacity was 2.6 Wh.

Comparative Example 4
A “Nafion” 117 membrane was used as the polymer electrolyte membrane, and a membrane electrode assembly and a polymer electrolyte fuel cell were produced in the same manner as in Example 6. The output was 7 mW / cm ² and was a low value. The energy capacity was 0.6 Wh, which was a low value.

  The polymer having an ionic group, the polymer electrolyte material or the polymer electrolyte component of the present invention can be applied to various applications. For example, it can be applied to filtration applications, concentration applications, ion exchange resin applications, various structural material applications, coating material applications, polymer actuator applications, extracorporeal circulation columns, medical applications such as artificial skin, and electrochemical applications. Examples of electrochemical applications include fuel cells, redox flow batteries, water electrolyzers, and chloroalkali electrolyzers. Of these, fuel cells are particularly preferred. For example, direct fuel cells using methanol or the like as fuel are used. It is done.

  As a use of the polymer electrolyte fuel cell of the present invention, a power supply source of a moving body is preferable. In particular, it is used in mobile device retailing, restaurants, transportation, transportation, etc. such as mobile phones, personal computers, PDAs (Portable Digital Assistance), wireless ID readers (RFID readers), video cameras (camcorders), and digital cameras. Electric power for mobile devices such as various handy terminals, electric shavers, vacuum cleaners, etc. It is preferably used as a supply source.

Claims (13)

A polymer having an ionic group containing an ionic group and a group of the following formula (A1).

(In the formula, T ¹ represents a secondary alkyl group or a tertiary alkyl group.) The polymer having an ionic group according to claim 1, wherein T ¹ in the formula (A1) is a cyclic alkyl group. The polymer having an ionic group according to claim 1 or 2, which has a skeleton containing a repeating unit of the following formula (P1).
^{-Y 11 -Z 11 -Y 21 -Z 21} - (P1)
(Wherein Y ¹¹ and Y ²¹ each represent O or S. At least one of Z ¹¹ and Z ²¹ represents a group represented by the formula (A1), and Z ¹¹ is substituted. A divalent group containing a good aromatic ring is represented, and Z ²¹ represents a divalent group containing an aromatic ring having an electron-withdrawing group. The polymer having an ionic group according to claim 3, wherein Z ¹¹ in the formula (P1) is any one of the following formulas (B1) to (B3).

(Wherein Q ¹ represents a direct bond, a methylene group, a carbonyl group, O or S, Q ² represents H, a methyl group or a phenyl group, Q ³ represents a carbonyl group or a sulfonyl group, Q ⁴ represents a substituent represented by O, S or N—R ¹ , and R ¹ represents H, an alkyl group or an aryl group. In Formula (B1), Q ¹ is a direct bond; in Formula (B2), Q ² is a phenyl group; in Formula (B3), Q ³ is a carbonyl group; and Q ⁴ is O Alternatively, the polymer having an ionic group according to claim 4, which is a substituent represented by N—R ¹ . Furthermore, the polymer which has an ionic group in any one of Claims 3-5 which has the frame | skeleton containing the repeating unit of a following formula (P2).
^{-Y 12 -Z 12 -Y 22 -Z 22} - (P2)
[Wherein Y ¹² and Y ²² each represent O or S. Z ¹² represents a divalent group containing an optionally substituted aromatic ring, and Z ²² represents a group represented by the following formula (C1).

(In the formula, Q ⁵ represents a carbonyl group or a sulfonyl group, and X represents H or an arbitrary cation.)]   The polymer having an ionic group according to any one of claims 1 to 6, wherein the ionic group is a sulfonic acid group or a sulfonimide group.   The polymer having an ionic group according to claim 7, wherein the ionic group is a sulfonic acid group.   The polymer electrolyte material which consists of a polymer which has an ionic group in any one of Claims 1-8.   A polymer electrolyte component comprising the polymer electrolyte material according to claim 9.   The membrane electrode assembly comprised using the polymer electrolyte component of Claim 10.   A polymer electrolyte fuel cell comprising the membrane electrode assembly according to claim 11. The polymer electrolyte fuel cell according to claim 12, wherein the polymer electrolyte fuel cell is a direct fuel cell using at least one selected from an organic compound having 1 to 6 carbon atoms and a mixture of the organic compound and water as a fuel.