JP2006206779A - Sulfonic group-containing polymer, polymer composition comprising said polymer, ion exchange resin and ion exchange membrane obtained using said polymer, membrane/electrode assembly and fuel cell obtained using said ion exchange membrane, and manufacturing method of said polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sulfonic group-containing polymer that suppresses fuel permeation to realize excellent performances in a solid polymer-type fuel cell. <P>SOLUTION: The sulfonic group-containing polymer has a branched structure where the structures represented by chemical formula (1) are linked together via a trivalent or tetravalent aromatic group (Ar<SP>5</SP>). In the formula, X is an -S(=O)<SB>2</SB>- or -C(=O)- group; Y is H or a monovalent cation; Z<SP>1</SP>and Z<SP>2</SP>are either one of O and S; Ar<SP>1</SP>and Ar<SP>2</SP>are each a bivalent aromatic group; Ar<SP>3</SP>and Ar<SP>4</SP>are each a specific aromatic group; and n and m are each independently such an integer of at least 1 that n+m is at least 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sulfonic acid group-containing polymer having a novel structure, a composition of the polymer, an ion exchange resin using the polymer, an ion exchange membrane, a membrane / electrode assembly, a fuel cell, and a method for producing the polymer.

  In recent years, new power generation technologies with excellent energy efficiency and environmental friendliness have attracted attention. Above all, polymer electrolyte fuel cells using polymer electrolyte membranes have high energy density, and because they have features such as being easy to start and stop because of lower operating temperatures than other types of fuel cells. Developments as power supply devices for electric vehicles and distributed power generation are advancing. Among solid polymer fuel cells, a direct methanol fuel cell that directly supplies methanol as a fuel can be miniaturized, and is being developed for applications such as power supplies for personal computers and portable devices.

  As the polymer solid electrolyte membrane, a membrane containing a proton conductive ion exchange resin is usually used. In addition to proton conductivity, the polymer solid electrolyte membrane must have characteristics such as fuel permeation deterrence and mechanical strength that prevent permeation of hydrogen and the like of the fuel. As such a polymer solid electrolyte membrane, for example, a membrane containing a perfluorocarbon sulfonic acid polymer into which a sulfonic acid group is introduced as represented by Nafion (registered trademark) manufactured by DuPont, USA is known.

  However, perfluorocarbon sulfonic acid ion exchange membranes have a relatively high permeability for fuels such as hydrogen and methanol, and it is necessary to suppress the permeation of fuel in order to obtain higher performance as a fuel cell.

In particular, in direct methanol fuel cells that use aqueous methanol as fuel, the output decreases when methanol passes through the membrane and moves to the air electrode. For perfluorocarbon sulfonic acid polymer membranes, methanol with a high concentration of aqueous methanol is used. There was a problem that the amount of permeated light was increased and the output was significantly reduced. Therefore, non-perfluorocarbon sulfonic acid ion exchange membranes having low methanol permeability have been studied. (For example, see Patent Documents 1 to 3)
However, although the hydrocarbon-based ion exchange membranes described in these patent documents are less permeable to methanol than the perfluorocarbon sulfonic acid-based ion exchange membranes, the performance when used as a fuel cell is not sufficient. There is a need for excellent ion exchange membranes.
JP 2003-288916 A JP 2003-331868 A US Patent Application Publication No. 2002/0091225

  The present invention has been made to solve the above-described problems of the prior art, and includes a novel sulfonic acid group-containing polymer capable of suppressing permeation of fuel and obtaining excellent performance in a solid polymer fuel cell. An object of the present invention is to provide a manufacturing method thereof, an ion exchange membrane using the same, an ion exchange resin, a membrane / electrode assembly using the ion exchange membrane, and a fuel cell.

According to one aspect of the present invention, the structure represented by the following chemical formula (1) is connected to each other by a trivalent or tetravalent aromatic group (Ar ⁵ ) and has a branched structure. A sulfonic acid group-containing polymer is provided.

In the chemical formula (1), X is an —S (═O) ₂ — group or —C (═O) — group, Y is an H atom or a monovalent cation, and Z ¹ and Z ² are independent of each other. And Ar ¹ and Ar ² are each independently a divalent aromatic group, and Ar ³ is an aromatic group represented by chemical formulas (2) to (5). Ar ⁴ is any of the aromatic groups represented by the following chemical formulas (2) to (7), and n and m are each independently 1 such that n + m is 5 or more. It is an integer above.

In chemical formula (6) and chemical formula (7), Y is an H atom or a monovalent cation.

Preferably, the number of moles (o) of the structure represented by the chemical formula (1) and the number of moles (p) of Ar ⁵ are 0.7> p / o ≧ 0.2.

  Preferably, n + m is an integer of 10 or more.

Preferably, Ar ¹ and Ar ² have a structure represented by the following chemical formula (8).

Preferably, Ar ⁵ is any one of structures represented by the following chemical formulas (9) to (15).

  According to another aspect of the present invention, there is provided a polymer composition comprising any of the polymers described above.

  According to still another aspect of the present invention, an ion exchange resin comprising any of the above polymers is provided.

  According to still another aspect of the present invention, an ion exchange membrane comprising any one of the above polymers is provided.

  According to still another aspect of the present invention, there is provided a fuel cell comprising the polymer described in any of the above in the electrode layer and / or the bonding layer between the electrode layer and the ion exchange membrane. The

  According to still another aspect of the present invention, a membrane / electrode assembly comprising any one of the above polymers in the electrode layer and / or in the bonding layer between the electrode layer and the ion exchange membrane. Is provided.

  According to still another aspect of the present invention, there is provided a membrane / electrode assembly obtained using the above ion exchange membrane.

  According to still another aspect of the present invention, there is provided a fuel cell using any one of the above polymers and / or the above ion exchange membrane.

  According to still another aspect of the present invention, a fragrance having a branch in a molecule, which reacts an aromatic dihalogen compound having a halogen group activated by an electron-withdrawing group with a phenol compound and / or a thiophenol compound. Aromatic ether polymer and / or aromatic thioether polymer, wherein (A) an aromatic dihalogen compound having a halogen group activated by an electron-withdrawing group, a bisphenol compound and / or a bisthiophenol compound A first step of obtaining a halogen group-terminated oligomer by reacting such that the molar ratio of the bisphenol compound and / or bisthiophenol compound to the group dihalogen compound is in the range of 0.80 to 0.99; B) 3 or 4 phenolic hydroxyl groups in the molecule The polythiophenol compound and / or the polythiophenol compound having 3 or 4 thiophenolic mercapto groups is more than the number of moles of the phenolic hydroxyl group in the polyphenol compound and / or the thiophenolic mercapto group in the polythiophenol compound. A second step of reacting with the oligomer produced in the first step so that the number of moles of halogen groups in the oligomer produced in the first step is equal to or greater than equimolar, and having aromatic branching in the molecule Methods for producing ether polymers and / or aromatic thioether polymers are provided.

  Preferably, the first step and the second step are reacted by heating in an organic polar solvent in the presence of an alkali metal salt, in an inert gas atmosphere or in an air stream.

  Preferably, the ratio of the number of moles of the phenolic hydroxyl group of the polyphenol compound and / or the thiophenolic mercapto group of the polythiophenol compound to the number of moles of the halogen group in the oligomer obtained in the first step is 0.2 to Within the range of 0.6.

  Preferably, the aromatic dihalogen compound having a halogen group activated by an electron-withdrawing group includes any of the compounds represented by the following chemical formula (16) or chemical formula (17).

In chemical formula (16) and chemical formula (17), X is a halogen atom of F, Cl, I or Br, and Y is an alkali metal ion of Li, Na or K.

  Preferably, the aromatic dihalogen compound having a halogen group activated by an electron-withdrawing group further includes any one of compounds represented by the following chemical formulas (18) to (21).

In the chemical formulas (18) to (21), X is a halogen atom of F, Cl, I or Br.

  Preferably, the polyphenol compound or the polythiophenol compound contains any of the compounds represented by the following (22) to (28).

  Preferably, the bisphenol compound is 4,4'-dihydroxybiphenyl.

  Preferably, the alkali metal salt is potassium carbonate or sodium carbonate.

  Preferably, the organic polar solvent is either N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide or sulfolane.

  Preferably, the temperature at the time of heating is set within a range of 150 to 250 ° C.

  The ion exchange membrane obtained from the novel sulfonic acid group-containing polymer or the composition containing the polymer according to the present invention is superior in permeation suppression of fuel such as methanol as compared with conventional ion exchange membranes, and is used as a fuel cell. In this case, the energy use efficiency can be further improved. The method for producing the polymer of the present invention is a method suitable for producing the sulfonic acid group-containing polymer of the present invention.

(Sulfonic acid group-containing polymer)
The sulfonic acid group-containing polymer of the present invention has a structure in which the structure represented by the following chemical formula (1) is linked to each other by a trivalent or tetravalent aromatic group (Ar ⁵ ), and has a branched structure. It is a sulfonic acid group containing polymer characterized by having.

Here, in the chemical formula (1), X is an —S (═O) ₂ — group or —C (═O) — group, Y is an H atom or a monovalent cation, and Z ¹ and Z ² Are each independently an O atom or an S atom, Ar ¹ and Ar ² are each independently a divalent aromatic group, and Ar ³ is represented by chemical formulas (2) to (5). Ar ⁴ is any one of the aromatic groups, Ar ⁴ is any one of the aromatic groups represented by the following chemical formulas (2) to (7), and n and m are each independently n + m is 5 or more. Is an integer greater than or equal to 1

  Here, in chemical formulas (6) and (7), Y represents an H atom or a monovalent cation.

In the chemical formula (1), it is preferable that Z ¹ and Z ² are S atoms because oxidation resistance is improved. Further, it is preferable that X is a —S (═O) ₂ — group because the solubility of the polymer is improved. Y is an H atom or a monovalent cation. Examples of these include alkali metal ions such as H (proton), Na, K, and Li, ammonium ions, and quaternary ammonium cations. Among them, when Y is an H atom, proton conductivity is improved, and thus, for example, it can be suitably used as a raw material polymer for a proton exchange membrane for a fuel cell.

Z ¹ and Z ² are each independently a divalent aromatic group, and may be the same or different, and may be a plurality of types of groups. Although it is not necessarily limited to this, a specific example is shown below.

  Here, in said formula, R represents a methyl group and p represents the integer of 0-2.

  When p is 1 or 2, the electron density is increased by the electron donating property of the methyl group, which is preferable for the polymerization reaction of the polymer that is an electrophilic substitution reaction. In some cases, it may be difficult to obtain a polymer having a high degree of polymerization. Moreover, when p is 1 or 2, crosslinking between polymers can also be performed by a crosslinking reaction using a methyl group, for example, a photocrosslinking reaction with a carbonyl group. However, introduction of a methyl group increases the water absorption of the polymer and increases the swellability as an ion exchange membrane, which may be undesirable. In this way, it is preferable that p is 0 in consideration of the degree of polymerization of the polymer and the characteristics of the ion exchange membrane. Among these aromatic groups, structures represented by chemical formulas (29A), (29C), (29F), (29G), (29H), (29I), and (29M) are more preferable. The reason is that ion exchange membranes obtained from polymers having these structures exhibit moderate mechanical properties and excellent proton conductivity, swelling resistance and stability. (29A), (29C), (29F) and (29H) are more preferable. The reason is that ion exchange membranes obtained from polymers having these structures are particularly excellent in swelling resistance, oxidation resistance, and methanol permeability resistance among ion exchange membranes obtained from polymers having the above structures. . Of these, a structure represented by any of the following chemical formulas (29A ′) and (29B ′) is preferable. The reason is that ion exchange membranes obtained from polymers having these structures are particularly excellent in swelling resistance, oxidation resistance, and methanol permeability resistance among ion exchange membranes obtained from polymers having the above structures. . Furthermore, the structure represented by the chemical formula (29A ′) is most preferable. The reason is that ion exchange membranes obtained from polymers having these structures are particularly superior in swelling resistance and methanol permeation resistance among ion exchange membranes obtained from polymers having the above structure.

Ar ³ in the chemical formula (1) represents any of the aromatic groups represented by the chemical formulas (2) to (5). Among them, the group represented by the chemical formula (4) or (5) is preferable because methanol permeability is reduced, and the group represented by the chemical formula (2) is preferable because the solubility of the polymer is increased. Of these, the group of the chemical formula (5) is most preferable.

Ar ⁴ in the chemical formula (1) represents any of the aromatic groups represented by the chemical formulas (2) to (7). Y in the chemical formulas (6) and (7) is an H atom or a monovalent cation, specifically, an alkali metal ion such as H (proton), Na, K or Li, an ammonium ion, or a quaternary ammonium. A cation etc. can be mentioned as an example. Among them, when Y is H (proton), proton conductivity is improved, and thus, for example, it can be suitably used as a raw material polymer for a proton exchange membrane for a fuel cell. Of these, chemical formula (5) or (6) is preferred. The reason is that the structure of the chemical formula (5) can improve the swelling resistance when the ion exchange membrane is used, and the chemical formula (6) is a proton conductivity when the ion exchange membrane is used. This is because it can be improved.

Ar ⁵ represents a trivalent or tetravalent aromatic group. Although it does not specifically limit, a specific example is shown below.

  Among these, a group represented by the chemical formula (9), (10) or (14) is preferable because a polymer having a high degree of polymerization is easily obtained, and an oxidation resistance is a group represented by the chemical formula (12). Is preferable, and the group represented by the chemical formula (15) is preferable because a small amount exhibits an excellent effect. Of these, groups represented by the chemical formulas (9), (10) and (14) are more preferable.

  In the chemical formula (1), n and m each independently represent an integer of 1 or more such that n + m is 5 or more, and n + m is 10 or more, which makes it difficult for the polymer to gel during polymerization. Therefore, it is more preferable that it is 20 or more because methanol permeability in the case of an ion exchange membrane can be further reduced. When n + m is 100 or more, the degree of polymerization of the polymer becomes too high, the viscosity of the solution becomes remarkably high, and handling is difficult. The value of n + m is determined by the molecular weight of the polymer determined by any method such as gel distribution chromatography (GPC) or light scattering, and by nuclear magnetic resonance (NMR) or infrared spectroscopy (IR). It can be determined from the molecular structure of the repeating unit and the value of n / m determined by nuclear magnetic resonance (NMR). More simply, it can be evaluated by the logarithmic viscosity of the polymer solution measured by the method described later. It is possible to estimate n + m from the logarithmic viscosity by measuring the logarithmic viscosity of several types of polymers with known n + m and preparing a calibration curve. Although the relationship between the logarithmic viscosity and n + m varies depending on the structure of the polymer, the logarithmic viscosity of the structure represented by the formula (1) is preferably 0.1 dL / g or more, and preferably 0.2 dL / g or more. Is more preferably 0.3 dL / g or more. When the logarithmic viscosity exceeds 0.8 dL / g, the value of n + m becomes too large, and the viscosity of the polymer solution becomes extremely high, which is not preferable.

  The ratio of n to m (n / m) can be arbitrarily set between 1/99 and 99/1, but is preferably in the range of 10/90 to 50/50, more preferably 15 It is within the range of / 85 to 45/55. As n / m decreases, methanol permeability decreases but proton conductivity also decreases. Therefore, an excellent polymer for proton exchange membrane can be obtained by selecting an appropriate n / m ratio according to the purpose. it can. The value of n / m can be measured by comparing the number of protons having a specific chemical shift by nuclear magnetic resonance (NMR). The chemical shift is considered to be easily determined by those skilled in the art depending on the target monomer unit.

The number of moles (p) of the structure represented by Ar ⁵ is preferably 1> p / o ≧ 0.1 with respect to the number of moles (o) of the structure represented by the chemical formula (1). The range of 0.7 ≧ p / o ≧ 0.2 is more preferable, and the range of 0.4 ≧ p / o ≧ 0.2 is even more preferable. If p / o is too large, the polymer becomes a gel and cannot be polymerized, or the viscosity when it is made into a solution is remarkably increased. When p / o is less than 0.1, the amount of branching to the polymer becomes small, and the effect of suppressing methanol permeation becomes difficult to obtain.

  Specifically, the structure represented by the chemical formula (1) preferably has the structure represented by the following chemical formula (30) or (31) as the minimum repeating unit. In the repeating structure represented by the chemical formula (30) or (31), the chemical formula (30) or (31) may be independently and continuously bonded. In addition, the repetitive structure includes a case where they are alternately or randomly combined. For example, alternating bonding refers to bonding chemical formulas (30) and (31) in the order of (30), (31), (30), (31), (30). Including. Here, when the same repeating unit is continuously bonded, the same properties as the segmented block copolymer are exhibited, and proton conductivity, methanol permeability, and water absorption tend to increase. However, n and m must satisfy the condition of an integer of 1 or more such that n + m is 5 or more independently.

Here, in the chemical formula (30) or (31), X represents an —S (═O) ₂ — group or —C (═O) — group, Y represents an H atom or a monovalent cation, and Z ¹ and Z ² each independently represent either an O atom or an S atom, Ar ¹ and Ar ² each independently represent a divalent aromatic group, and Ar ³ represents a chemical formula (2) to (5). N and m each independently represent an integer of 1 or more such that n + m is 5 or more.

  In the chemical formula (1), when Y is H (proton), it is suitable as a proton exchange resin or a proton exchange membrane. Y represents an H atom or a monovalent cation. Examples of the monovalent cation include alkali metal ions such as Na, K and Li, ammonium ions, and quaternary ammonium salts. When the monovalent cation is an alkali metal ion such as Na, K or Li, the thermal stability of the sulfonic acid group is increased, and the polymer can be processed at a high temperature in processing processes such as film formation, dissolution and molding. Can improve the workability. The sulfonic acid group that is an alkali metal salt can be converted to a free sulfonic acid group by treating the polymer with a strong acid such as sulfuric acid, hydrochloric acid or perchloric acid or an aqueous solution thereof. A polymer having a free sulfonic acid group exhibits high proton conductivity, and can be used as a proton exchange resin or a proton exchange membrane. Among them, the proton exchange membrane can be used as an electrolyte of a polymer electrolyte fuel cell, and a fuel cell having excellent performance can be obtained by using the polymer of the present invention.

  Specific examples of preferable structures of the chemical formula (1) are shown below, but the scope of the present invention is not limited thereto.

  Among these, chemical formulas (32-A), (32-B), (32-C), (32-D), (32-Q), (32-R), (32-S) and (32-) T) is more preferred. The reason is that the proton exchange membrane is excellent in proton conductivity, swelling resistance, methanol resistance, stability, and mechanical properties. Further, chemical formulas (32-A), (32-D), (32-Q) and (32-T) are more preferable. The reason is that the proton exchange membrane is more excellent in swelling resistance, methanol permeability resistance and oxidation resistance stability. The chemical formula (32-Q) is most preferable. The reason is that the proton exchange membrane is further excellent in swelling resistance and methanol permeation resistance.

  The degree of polymerization of the structure represented by the chemical formula (1) can be evaluated by the logarithmic viscosity of the polymer solution measured by the method described later. The logarithmic viscosity of the polymer is preferably in the range of 0.1 to 1.0 dL / g. If it is less than 0.1 dL / g, it is difficult to polymerize the polymer, and if it is more than 1 dL / g, the degree of polymerization of the final polymer becomes too high, and the viscosity of the polymer solution increases remarkably. It is not preferable because gelation occurs in the inside. More preferably, it is in the range of 0.3 to 0.8 dL / g.

(Manufacturing method)
The present invention also provides an aromatic ether polymer having a branch in the molecule, which reacts an aromatic dihalogen compound having a halogen group activated by an electron-withdrawing group with a phenol compound and / or a thiophenol compound. Or an aromatic thioether polymer, wherein (A) an aromatic dihalogen compound having a halogen group activated by the electron-withdrawing group, a bisphenol compound and / or a bisthiophenol compound, A first step of obtaining a halogen-group-terminated oligomer by reacting such that the molar ratio of the bisphenol compound and / or bisthiophenol compound is within the range of 0.80 to 0.99, and (B) A polymer having 3 or 4 phenolic hydroxyl groups in the molecule The polythiophenol compound having 3 or 4 phenolic compounds and / or thiophenolic mercapto groups is more than the number of moles of phenolic hydroxyl groups in the polyphenolic compounds and / or thiophenolic mercapto groups in the polythiophenolic compounds. A second step of reacting with the oligomer produced in the first step so that the number of moles of halogen groups in the oligomer produced in the first step is equal to or greater than equimolar, and having a branch in the molecule A method for producing an aromatic ether polymer and / or an aromatic thioether polymer is provided.

Here, the first step substantially corresponds to the step of manufacturing the structure of the chemical formula (1), and the second step substantially corresponds to the step of combining the structure of the chemical formula (1) and Ar ^5. To do.

  In the production method of the present invention, as a method for introducing a sulfonic acid group into the produced aromatic ether polymer and / or aromatic thioether polymer, in the first step, the chemical formula (16) or the chemical formula (17) is used. In addition, a compound having a sulfonic acid group is used as one of the components of the monomer, or a polymer obtained by polymerization using a monomer having no sulfonic acid group is reacted with a sulfonating agent such as sulfuric acid, chlorosulfuric acid or sulfuric anhydride. It can also be obtained.

  Here, examples of the electron-withdrawing group include a sulfone group, a sulfonyl group, a carbonyl group, a nitro group, a trifluoromethyl group, a sulfonic acid group, a halogen group, and a cyano group. The halogen group activated with an electron-withdrawing group represents a halogen group with an electron-withdrawing group bonded to the ortho or para position of the aromatic ring to which the halogen group is bonded. As the aromatic dihalogen compound having a halogen group activated with an electron-withdrawing group, a compound having a sulfonic acid group and a compound having no halogen group can be used.

  As the aromatic dihalogen compound having a sulfonic acid group and a halogen group activated with an electron-withdrawing group, for example, compounds having a structure represented by the above chemical formula (16) or (17) are preferable, but are not limited thereto. It is not a thing.

  Examples of the compound having the structure represented by the chemical formula (16) or (17) include 3,3′-disulfo-4,4′-dichlorodiphenylsulfone, 3,3′-disulfo-4,4′-difluoro. Diphenyl sulfone, 3,3′-disulfo-4,4′-dichlorodiphenyl ketone, 3,3′-disulfo-4,4′-difluorodiphenyl sulfone, and salts of these sulfonic acid groups with monovalent cationic species And the like. The monovalent cation species may be sodium, potassium, other metal species, various amines, or the like, but is not limited thereto.

  Examples of the compound in which the sulfonic acid group is a salt include sodium 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone, sodium 3,3′-disulfonate-4,4′-difluorodiphenylsulfone. 3,3′-sodium disulfonate-4,4′-dichlorodiphenyl ketone, 3,3′-sodium disulfonate-4,4′-difluorodiphenylsulfone, 3,3′-sodium disulfonate-4,4 ′ Difluorodiphenyl ketone, potassium 3,3′-disulfonate 4,4′-dichlorodiphenyl sulfone, potassium 3,3′-disulfonate-4,4′-difluorodiphenyl sulfone, potassium 3,3′-disulfonate-4 , 4′-dichlorodiphenyl ketone, potassium 3,3′-disulfonate-4,4′-difur B diphenyl sulfone, or 3,3'-disulfonic acid potassium-4,4'-difluoro diphenyl ketone, and the like can be mentioned, but not limited thereto.

  Since these aromatic dihalogen compounds having a sulfonic acid group may have bound water in the sulfonic acid group, it is preferable to dry them prior to the polymerization reaction in the first step. Drying can be performed by heating or drying under reduced pressure. The drying temperature may be in the range of 50 to 200 ° C, but more preferably 80 to 120 ° C. In the case of drying by heating, it is preferably performed in an inert gas atmosphere or an air stream. The atmosphere of the inert gas is not limited, but can be formed, for example, by replacing a gas in a predetermined space with a rare gas, a nitrogen gas, or the like. In addition, the air flow of the inert gas can be achieved by always performing the above replacement.

  Examples of aromatic dihalogen compounds that have a halogen group that has no sulfonic acid group and is activated with an electron-withdrawing group include 4,4′-dichlorodiphenylsulfone, 4,4′-dichlorobenzophenone, and 4,4 ′. -Dichlorodiphenylphosphine oxide, 4,4'-bis (4-chlorophenylsulfonyl) biphenyl, 2,6-dichlorobenzonitrile, 2,4-dichlorobenzonitrile, 2,6-dichloro-1-trifluoromethylbenzene, 2 , 4-dichloro-1-trifluoromethylbenzene, 4,4′-difluorodiphenylsulfone, 4,4′-difluorobenzophenone, 4,4′-difluorodiphenylphosphine oxide, 4,4′-bis (4-fluorophenyl) Sulfonyl) biphenyl, 2,6-difluorobenzonitrile, , 4-difluorobenzonitrile, 2,6-difluoro-1-trifluoromethyl benzene, or 2,4-difluoro 1- it can be mentioned trifluoromethylbenzene but not limited thereto.

  Preferable examples of the aromatic dihalogen compound include compounds having a structure represented by the above chemical formulas (18) to (21). Among the compounds having the structures represented by the chemical formulas (18) to (21), 4,4′-dichlorodiphenylsulfone, 4,4′-difluorodiphenylsulfone, 2,6-dichlorobenzonitrile, 2,6-difluoro Benzonitrile, 4,4′-dichlorobenzophenone, and 4,4′-difluorobenzophenone are more preferable, and 2,6-dichlorobenzonitrile and 2,6-difluorobenzonitrile are most preferable. The reason is that when a proton exchange membrane is used, the swelling resistance and methanol permeability resistance can be improved.

  In the production method of the present invention, the bisphenol compound or bisthiophenol compound represents a compound having two phenolic hydroxyl groups or thiophenolic mercapto groups in the molecule. A phenolic hydroxyl group represents a hydroxyl group directly bonded to an aromatic group such as a benzene ring, a naphthalene ring, or a pyridine ring. A thiophenolic mercapto group represents a mercapto group bonded directly to an aromatic group such as a benzene ring, a naphthalene ring or a pyridine ring. In the bisphenol compound or bisthiophenol compound, a phenolic hydroxyl group or a thiophenolic mercapto group may be bonded in the same aromatic group, or bonded to each of two or more aromatic groups linked to each other. You may do it. In this case, the aromatic group includes only a phenolic hydroxyl group, a thiophenolic mercapto group, and a mixture of these groups.

  Examples of bisphenol compounds and bisthiophenol compounds include, but are not limited to, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) Fluorene, 9,9-bis (4-mercaptophenyl) fluorene, 9,9-bis (3-methyl-4-mercaptosiphenyl) fluorene, 4,4′-biphenol, 4,4′-dimercaptobiphenyl, bis (4-hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 2,2-bis (4 -Hydroxyphenyl) butane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4- Droxy-3,5-dimethylphenyl) propane, bis (4-hydroxy-3,5-dimethylphenyl) methane, bis (4-hydroxy-2,5-dimethylphenyl) methane, bis (4-hydroxyphenyl) phenylmethane Bis (4-hydroxyphenyl) diphenylmethane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, hydroquinone, resorcin, 1,4-dimercaptobenzene, 1,3-dimercaptobenzene, bis (4-hydroxy Phenyl) ketone, 4,4′-thiobisbenzenethiol, 4,4′-thiodiphenol, 3-methyl-4,4′-dihydroxy-p-terphenyl, 4,4′-dihydroxy-p-terphenyl 1,3-bis (4-hydroxy) adamantane, 2,2-bis (4-hydroxy) Proxy) adamantane, dihydroxy naphthalenes, dimercapto naphthalenes, may be mentioned dihydroxy quinoline or dihydropyridines. Among them, 4,4′-biphenol, 9,9-bis (4-hydroxyphenyl) fluorene, 4,4′-dimercaptobiphenyl, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 4,4′- Thiobisbenzenethiol is preferred. The reason is that when a proton exchange membrane is used, it is excellent in proton conductivity, swelling resistance, methanol permeability, stability, and mechanical properties. Further, 4,4'-biphenol, 9,9-bis (4-hydroxyphenyl) fluorene, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, and 4,4'-thiobisbenzenethiol are more preferable. The reason is that when a proton exchange membrane is used, it is more excellent in swelling resistance, methanol permeability, and oxidation resistance. Furthermore, 4,4'-biphenol is particularly preferred. The reason is that when a proton exchange membrane is used, the swelling resistance and methanol permeability resistance are further excellent.

  The bisphenol compound or bisthiophenol compound may have an ionic group such as a sulfonic acid group, a phosphonic acid group, or a phosphoric acid group.

  In the production method of the present invention, it is preferable that the first step and the second step are heated and reacted in an organic polar solvent in the presence of an alkali metal salt and in an inert gas atmosphere or air stream. The reaction is preferably carried out by an aromatic nucleophilic substitution reaction. The presence of the alkali metal salt increases the reactivity of the bisphenol compound or bisthiophenol compound, and a polymer having a high degree of polymerization can be easily obtained. By reacting in an inert gas atmosphere or air stream, bisphenol can be obtained. A polymer with a high degree of polymerization can be obtained by controlling side reactions such as oxidation or decomposition of the compound or bisthiophenol compound, and a polymer with an increased degree of polymerization can be precipitated by reacting in an organic polar solvent. This is because a polymer with a high degree of polymerization can be obtained by dissolving in a solvent, and a polymer with a high degree of polymerization can be obtained by heating to increase the reaction rate.

  In the production method of the present invention, examples of the alkali metal salt include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and the like, but aromatic diols and aromatic dimercapto compounds Can be used without being limited to these as long as they can have an active phenoxide structure. Of these, potassium carbonate or sodium carbonate is preferred. The alkali metal salt can be polymerized satisfactorily when used in an amount of 100 mol% or more based on the bisphenol compound or bisthiophenol compound, and preferably in the range of 105 to 125 mol% based on the bisphenol compound. An excessive amount of alkali metal salt is not preferable because it causes side reactions such as decomposition.

  In the present invention, the reaction in the first step is a polymerization reaction, but can be performed in a temperature range of 0 to 350 ° C. Moreover, it is preferable that it exists in the temperature range of 50-300 degreeC, and it is still more preferable that it exists in the range of 150-250 degreeC. When the temperature is lower than 0 ° C., the reaction does not proceed sufficiently, and when the temperature is higher than 350 ° C., the polymer tends to be decomposed. The reaction can be carried out in the absence of a solvent, but is preferably carried out in a solvent. Examples of organic polar solvents that can be used include, but are not limited to, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, diphenyl sulfone, or sulfolane. It is not limited as long as it can 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.

  In the present invention, water may be generated as a by-product in the aromatic nucleophilic substitution reaction. In this case, regardless of the polymerization solvent, water can be removed from the system as an azeotrope by coexisting toluene or the like in the reaction system. As a method for removing water out of the system, a water absorbing material such as molecular sieve can also be used. Further, the polymerization solvent and water can be distilled off simultaneously to remove water. When the aromatic nucleophilic substitution reaction is carried out in a solvent, it is preferable to charge the monomer so that the resulting polymer concentration is 5 to 50% by mass. When the amount is less than 5% by mass, the degree of polymerization tends to be difficult to increase. On the other hand, when the amount is more than 50% by mass, the viscosity of the reaction system becomes too high, and post-treatment of the reaction product tends to be difficult. The polymerization reaction is preferably performed in an atmosphere of an inert gas such as nitrogen or argon or in an air stream.

  In the first step, an aromatic dihalogen compound is reacted with a bisphenol compound and / or a bisthiophenol compound so that the aromatic dihalogen compound is excessive to obtain an oligomer having a halogen group terminal represented by the chemical formula (1). The molar ratio of the bisphenol compound and / or bisthiophenol compound to the aromatic dihalogen compound is in the range of 0.80 to 0.99, more preferably in the range of 0.90 to 0.98. A range of 91 to 0.97 is more preferable. The reason is that if the molar ratio is too small, the molecular weight of the oligomer becomes small, and gelation tends to occur when reacting with the polyphenol compound and / or polythiophenol compound in the second step in the present invention, and the viscosity of the polymer solution is remarkably high. This is because it is not preferable because it rises or the gel becomes a foreign substance insoluble in the solvent and the presence in the proton exchange membrane increases the possibility of adversely affecting the quality and characteristics. On the other hand, if the molar ratio is 1, the molecular weight of the oligomer becomes too large, which is not preferable because the viscosity of the polymer solution is remarkably increased or the degree of polymerization is difficult to control. Furthermore, when the molar ratio is larger than 1, a halogen-terminated oligomer cannot be obtained and cannot be reacted with a polyphenol compound and / or a polythiophenol compound in the second step in the present invention.

  In the first step of the present invention, the reaction is preferably carried out until there is no unreacted phenolic hydroxyl group or thiophenolic mercapto group. The end point of the reaction can be judged by measuring the viscosity of the solution and the logarithmic viscosity of the oligomer and becoming constant.

  After the completion of the reaction, the oligomer obtained in the first step in the present invention may be once isolated from the polymerization solution and then reacted with a polyphenol compound and / or a polythiophenol compound. In addition, a polythiophenol compound may be added for further reaction. When a polyphenol compound and / or polythiophenol compound is added to the polymerization solution for further reaction, if an alkali metal salt is insufficient relative to the phenolic hydroxyl group and / or thiophenolic mercapto group, an appropriate amount An alkali metal salt can be added and reacted.

  In the production method of the present invention, in the second step, a polyphenol compound having 3 or 4 phenolic hydroxyl groups and / or a polythiophenol compound having 3 or 4 thiophenolic mercapto groups in the molecule is converted into a polyphenol compound. The number of moles of halogen groups in the oligomer produced in the first step is equal to or more than the number of moles of phenolic hydroxyl groups and / or thiophenolic mercapto groups in the polythiophenol compound, It is a step of reacting with the oligomer produced in the first step.

  In the present invention, the end of the halogen group of the oligomer represented by formula (1) is equimolar or more with respect to the phenolic hydroxyl group of the polyphenol compound and / or the thiophenolic mercapto group of the polythiophenol compound. All of the phenolic hydroxyl group of the compound and / or the thiophenolic mercapto group of the polythiophenol compound can be reacted. If unreacted phenolic hydroxyl groups and / or thiophenolic mercapto groups remain, it becomes difficult to obtain effects such as suppression of methanol permeation.

  The ratio of the number of moles of the phenolic hydroxyl group of the polyphenol compound and / or the thiophenolic mercapto group of the polythiophenol compound to the number of moles of the halogen group of the oligomer may be 1 or less, but 0.2 to 0.8 Is more preferable, and the range of 0.2 to 0.6 is more preferable. This is because gelation tends to occur as the value approaches 1. On the other hand, if it is 0.2 or less, the polymer properties may not be sufficiently improved.

  The polyphenol compound or polythiophenol compound represents a compound having 3 or 4 phenolic hydroxyl groups or thiophenolic mercapto groups in the molecule. Any known compound can be used as long as it is such a compound. Although it is not limited to these, It is preferable to use the compound of the said Chemical formula (22)-(28), and when it is a compound represented by Chemical formula (22), (23) or (27) especially, It is preferable because a polymer having a high degree of polymerization can be easily obtained. A compound represented by the chemical formula (25) is preferable because oxidation resistance is improved. A compound represented by the chemical formula (28) is excellent in a small amount. Is preferable. Of these, compounds represented by the chemical formula (22), (23) or (27) are more preferable.

  In the second step, after completion of the polymerization reaction, the solvent is removed from the reaction solution by evaporation, and the residue is washed as necessary to obtain the desired polymer. In addition, the polymer can be obtained by precipitating the polymer as a solid by adding the reaction solution in a solvent having low polymer solubility, and collecting the precipitate by filtration. Examples of the solvent having low polymer solubility include water and acetone. In addition, a polymer solution can be obtained by removing by-product salts by filtration.

(Physical properties)
Further, the sulfonic acid group-containing polymer in the present invention preferably has a polymer log viscosity measured by a method described later of 0.1 or more. When the logarithmic viscosity is less than 0.1 dL / g, the membrane tends to become brittle when molded as an ion exchange membrane. The logarithmic viscosity is more preferably 0.3 dL / g or more, still more preferably 1.0 dL / g or more. On the other hand, if the logarithmic viscosity exceeds 3 dL / g, problems in processability such as difficulty in dissolving the polymer occur, which is not preferable. As a solvent for measuring the logarithmic viscosity, polar organic solvents such as N-methylpyrrolidone and N, N-dimethylacetamide can be generally used. When the solubility in these is low, concentrated sulfuric acid is used. It can also be measured.

  The ion exchange capacity of the sulfonic acid group-containing polymer in the present invention is preferably 0.1 meq / g, more preferably 3.5 meq / g or less. A small ion exchange capacity is not preferable because proton conductivity decreases. As the ion exchange capacity increases, proton conductivity increases, but at the same time, problems such as membrane swelling and water dissolution are likely to occur. A more preferred range is 0.5 to 2.5 meq / g, and a further preferred range is 0.8 to 1.8 meq / g.

(Use)
The sulfonic acid group-containing polymer in the present invention can be used as a simple substance, but can also be used as a resin composition in combination with other polymers. Examples of these polymers include polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyamides such as nylon 6, nylon 6,6, nylon 6,10 and nylon 12, polymethyl methacrylate and polymethacrylate. Acrylate resins such as polymethyl acrylate, polyacrylic acid esters, polyacrylic acid resins, polymethacrylic acid resins, polyethylene, polypropylene, various polyolefins including polystyrene and diene polymers, polyurethane resins, cellulose acetate, Cellulosic resins such as ethyl cellulose, polyarylate, aramid, polycarbonate, polyphenylene sulfide, polyphenylene oxide, polysulfone, polyether Heat curing of aromatic polymers such as sulfone, polyether ether ketone, polyether imide, polyimide, polyamide imide, polybenzimidazole, polybenzoxazole, polybenzthiazole, epoxy resin, phenol resin, novolac resin, benzoxazine resin There are no particular restrictions on the conductive resin. A resin composition with a basic polymer such as polybenzimidazole or polyvinylpyridine can be said to be a preferred combination for improving polymer dimensionality. If a sulfonic acid group is further introduced into these basic polymers, the processability of the composition becomes more preferable. When used as these resin compositions, the sulfonic acid group-containing polymer of the present invention is preferably contained in an amount of 50% by mass or more and less than 100% by mass of the entire resin composition. More preferably, it is 70 mass% or more and less than 100 mass%. When the content of the sulfonic acid group-containing polymer of the present invention is less than 50% by mass of the whole resin composition, the sulfonic acid group concentration of the ion exchange membrane containing this resin composition is lowered, and good ion conductivity is obtained. In addition, the unit containing a sulfonic acid group tends to be a discontinuous phase and the mobility of ions to be conducted tends to be lowered. In addition, the composition of the present invention, if necessary, for example, an antioxidant, a heat stabilizer, a lubricant, a tackifier, a plasticizer, a crosslinking agent, a viscosity modifier, an antistatic agent, an antibacterial agent, an antifoaming agent, Various additives such as a dispersant and a polymerization inhibitor may be included.

  The sulfonic acid group-containing polymer and the resin composition thereof in the present invention can be dissolved in an appropriate solvent to form a solution composition. Examples of the solvent include aprotic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and hexamethylphosphonamide, and alcohols such as methanol and ethanol. An appropriate one can be selected, but is not limited thereto. A plurality of these solvents may be used as a mixture within a possible range. The compound concentration in the solution is preferably in the range of 0.1 to 50% by mass. If the compound concentration in the solution is less than 0.1% by mass, it tends to be difficult to obtain a good molded product, and if it exceeds 50% by mass, the workability tends to deteriorate.

  The ion exchange membrane of the present invention can be obtained from the composition containing the sulfonic acid group-containing ion exchange resin of the present invention by any method such as extrusion, rolling or casting. Among these, it is preferable to mold from a solution dissolved in an appropriate solvent. A method of obtaining a molded body from a solution can be performed using a conventionally known method. For example, the molded product can be obtained by removing the solvent by heating, drying under reduced pressure, or immersing in a solvent that does not dissolve the polymer that can be mixed with the solvent that dissolves the polymer. Examples of the solvent that does not dissolve the polymer include water, but are not limited thereto. When the solvent is an organic solvent, it is preferable to distill off the solvent by heating or drying under reduced pressure. At this time, if necessary, it can be molded in a form combined with other compounds. When combined with a compound having a similar dissolution behavior, it is preferable in that good molding can be achieved. The sulfonic acid group in the molded article thus obtained may contain a salt form with a cationic species, but it is converted to a free sulfonic acid group by acid treatment if necessary. You can also. Since the sulfonic acid group in the polymer is easily decomposed at high temperatures, the heat stability of the sulfonic acid group is improved when processing with alkali metal salts such as Na and K, and decomposition during heating is suppressed. be able to.

  The most preferable method for forming an ion exchange membrane from a sulfonic acid group-containing polymer and a resin composition thereof in the present invention is casting from a solution, and the solvent is removed from the cast solution as described above to remove the ion exchange membrane. Can be obtained. Examples of the solution include a solution using an organic solvent such as N-methylpyrrolidone, N, N-dimethylformamide, and dimethyl sulfoxide, and in some cases, an alcohol solvent. The removal of the solvent is preferably by drying in view of the uniformity of the ion exchange membrane. Moreover, in order to avoid decomposition | disassembly and alteration of a compound or a solvent, it can also dry at the lowest temperature possible under reduced pressure. Further, when the viscosity of the solution is high, when the substrate or the solution is heated and cast at a high temperature, the viscosity of the solution is lowered and the casting can be easily performed. The thickness of the solution at the time of casting is not particularly limited, but is preferably 10 to 2000 μm. More preferably, it is 50-1500 micrometers. If the thickness of the solution is thinner than 10 μm, the form as an ion exchange membrane tends to be not maintained, and if it is thicker than 2000 μm, a non-uniform film tends to be easily formed. As a method for controlling the cast thickness of the solution, a known method can be used. For example, the thickness can be controlled with the amount and concentration of the solution with a constant thickness using an applicator, a doctor blade, or the like, and with a cast area constant using a glass petri dish or the like. The cast solution can obtain a more uniform film by adjusting the solvent removal rate. For example, in the case of heating, the evaporation rate can be reduced by lowering the temperature in the first stage. In addition, when immersed in a non-solvent such as water, the coagulation rate of the compound can be adjusted by leaving the solution in air or an inert gas for an appropriate time. When used as an ion exchange membrane, the sulfonic acid group in the membrane may contain a metal salt, but can be converted to free sulfonic acid by an appropriate acid treatment. In this case, it is also effective to immerse the membrane in an aqueous solution of sulfuric acid, hydrochloric acid, or the like with or without heating.

  The ion exchange membrane in the present invention can be of any thickness, but if it is 10 μm or less, it becomes difficult to satisfy the predetermined characteristics, so that it is preferably 10 μm or more, and more preferably 20 μm or more. Moreover, since manufacture will become difficult when it becomes 300 micrometers or more, it is preferable that it is 300 micrometers or less. A more preferable range is within a range of 20 to 100 μm, and a more preferable range is 20 to 50 μm.

  The membrane / electrode assembly of the present invention can be obtained by bonding the ion exchange membrane of the present invention to an electrode. As a method for producing this joined body, a conventionally known method can be used. For example, an adhesive is applied to the electrode surface to bond the ion exchange membrane and the electrode, or an ion exchange membrane and the electrode. There are a method of heating and pressurizing, a method of pre-swelling the ion exchange membrane with water or the like, and then joining the electrode. Among these, the method of applying and bonding an adhesive mainly composed of the sulfonic acid group-containing polymer and the resin composition thereof to the electrode surface is preferred. This is because the adhesion between the ion exchange membrane and the electrode is improved, and it is considered that the proton conductivity of the ion exchange membrane is less impaired.

  The fuel cell of the present invention can be produced using the ion exchange resin membrane or the ion exchange membrane of the present invention. For use in a proton exchange membrane for a fuel cell, it is preferable that the sulfonic acid group is a free acid because proton conductivity increases. The ion exchange membrane of the present invention is suitable for a polymer electrolyte fuel cell, but is particularly suitable for a direct methanol fuel cell using methanol as a fuel. Moreover, it can be used suitably also for the fuel cell which uses other substances, such as dimethyl ether and hydrogen, as a fuel, and can be used for arbitrary uses known as ion exchange membranes, such as an electrolytic membrane and a separation membrane.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these Examples. Various measurements were performed as follows.

  Logarithmic viscosity: The polymer powder was dissolved in N-methylpyrrolidone at a concentration of 0.5 g / dl, and the viscosity was measured using a Ubbelohde viscometer in a constant temperature bath at 30 ° C., and the logarithmic viscosity ln [ta / tb] / Evaluation was made in c) (ta is the number of seconds that the sample solution was dropped, tb was the number of seconds that the solvent was dropped, and c was the polymer concentration).

Proton conductivity: A platinum wire (diameter: 0.2 mm) is pressed against the surface of a strip-shaped membrane sample on a self-made measurement probe (manufactured by Teflon (registered trademark)), and the sample is held in water at 25 ° C. The impedance between them was measured by SOLARTRON 1250 FREQUENCY RESPONSE ANALYSER. The measurement was performed while changing the distance between the electrodes, and the conductivity obtained by canceling the contact resistance between the film and the platinum wire was calculated from the gradient obtained by plotting the distance measured between the electrodes and the resistance measurement value estimated from the CC plot.
Conductivity [S / cm] = 1 / film width [cm] × film thickness [cm] × resistance interelectrode gradient [Ω / cm].

Methanol permeability: The liquid fuel permeation rate of the ion exchange membrane was measured as the methanol permeation rate by the following method. An ion exchange membrane immersed in a 5 M (mol / liter) aqueous methanol solution adjusted to 25 ° C. for 24 hours is sandwiched in an H-type cell, 100 ml of 5 M aqueous methanol solution is placed on one side of the cell, and 100 ml of ultrapure water ( 18 MΩ · cm) was injected, and the amount of methanol diffusing into the ultrapure water through the ion-exchange membrane while stirring the cells on both sides at 25 ° C. was calculated using a gas chromatograph ( The area of the ion exchange membrane is 2.0 cm ² ). A methanol permeability coefficient was determined from the obtained methanol permeation rate and the film thickness of the sample.

Power generation evaluation: After adding and dampening a small amount of ultrapure water and isopropyl alcohol to Pt / Ru catalyst-supporting carbon (TEC 61E54, Tanaka Kikinzoku Kogyo Co., Ltd.), a DuPont 20% Nafion solution (product number: SE-20192) The Pt / Ru catalyst-supported carbon and Nafion were added so that the weight ratio was 2.5: 1. Next, stirring was performed to prepare an anode catalyst paste. The catalyst paste was applied to Toray carbon paper TGPH-060 to be a gas diffusion layer by screen printing so that the adhesion amount of platinum was 2 mg / cm ^2, and a carbon paper with an electrode catalyst layer for anode was produced. . Further, after adding a small amount of ultrapure water and isopropyl alcohol to a Pt catalyst-supporting carbon (Tanaka Kikinzoku Kogyo Co., Ltd. TEC10V40E) and moistening it, a DuPont 20% Nafion solution (product number: SE-20192) is added to the Pt catalyst-supporting carbon. A cathode catalyst paste was prepared by adding carbon and Nafion at a weight ratio of 2.5: 1 and stirring. This catalyst paste was applied and dried on Toray carbon paper TGPH-060 that had been subjected to water-repellent treatment so that the amount of platinum deposited was 1 mg / cm ² , thereby producing a carbon paper with an electrode catalyst layer for cathode. By sandwiching the membrane sample between the two types of carbon paper with the electrode catalyst layer so that the electrode catalyst layer is in contact with the membrane sample, pressurizing and heating at 130 ° C. and 8 MPa for 3 minutes by a hot press method, A membrane-electrode assembly was obtained. This joined body was incorporated into an evaluation fuel cell FC25-02SP manufactured by Electrochem, and a power generation test was performed using a fuel cell power generation tester (manufactured by Toyo Corporation). Power generation was performed at a cell temperature of 40 ° C. while supplying high purity air gas (80 ml / min) adjusted to 40 ° C. and a 5 mol / L aqueous methanol solution (1.5 ml / min) to the anode and the cathode, respectively. . The output voltage at a current density of 0.01 A / cm ² was evaluated.

  Ion exchange capacity: A sample dried for 1 hour at 100 ° C. and allowed to stand overnight at room temperature in a nitrogen atmosphere was weighed, stirred with an aqueous sodium hydroxide solution, and then ion exchange capacity was determined by back titration with an aqueous hydrochloric acid solution.

<Example 1>
First, the portion represented by the chemical formula (1) was synthesized in the first step. Sodium 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone (abbreviation: S-DCDPS) 9.971 g (20.30 mmol), 2,6-dichlorobenzonitrile (abbreviation: DCBN) 8.147 g (47 .36 mol), 4,4′-dihydroxybiphenyl (abbreviation: BP) 12.347 g (66.31 mmol), potassium carbonate 10.539 g (76.25 mmol), and dried molecular sieve 3-A 7 g in a 200 ml four-necked flask. And then flushed with nitrogen.

To this, 80 ml of N-methyl-2-pyrrolidone (abbreviation: NMP) was added and stirred at 150 ° C. for 30 minutes, and then the reaction temperature was raised to 195 to 200 ° C. and reacted for 8 hours. (I) The molar ratio of the bisphenol compound and / or bisthiophenol compound to the aromatic dihalogen compound in Example 1 is 67.66 mmol in total of the number of moles of S-DCDPS and DCBN, which are aromatic dihalogen compounds, and bisphenol It is represented by a ratio of 66.31 mmol of BP which is a compound, and is 0.98. Next, the oligomer synthesized in the first step in the second step was reacted with the polythiophenol compound. Thereafter, the mixture was allowed to cool and when the temperature reached 150 ° C., 0.152 g (0.86 mmol) of trithiocyanuric acid (abbreviation: TCA) was added and stirred for 10 hours while cooling, and then the heating temperature was again changed to 195 to 200. The temperature was raised to 0 ° C. and reacted for 8 hours. (Ii) The number of moles (o) of the structure represented by the chemical formula (1) in Example 1 is calculated based on the fact that all terminal groups are converted to chloro groups by reaction from the charged amounts of S-DCDPS, DCBN, and BP. -By subtracting the number of moles of BP from the total number of moles of DCDPS and DCBN, it can be determined that o = 1.35 mmol. The number of moles (p) of the trivalent or tetravalent aromatic group (Ar ⁵ ) is p = 0.86 mmol from the amount of TCA charged. Therefore, p / o is obtained as 0.86 / 1.35 = 0.64. (Iii) In addition, the number of moles of halogen groups in the oligomer obtained in the first step for synthesizing the structure represented by the chemical formula (1) is as follows per structure represented by the chemical formula (1). Since two halogen groups are contained in 1.35 × 2 = 2.70 mmol, it can be determined. On the other hand, since the number of moles of the phenolic hydroxyl group of the polyphenol compound and / or the thiophenolic mercapto group of the polythiophenol compound has three mercapto groups in one molecule in the case of TCA, 0.86 × 3 = 2 .58 mmol. From the above, the ratio of the number of moles of the phenolic hydroxyl group of the polyphenol compound and / or the thiophenolic mercapto group of the polythiophenol compound to the number of moles of the halogen group in the oligomer obtained in the first step is 2. 58 / 2.70 = 0.96.

  Thereafter, the precipitated molecular sieve was removed, and the resultant was precipitated in water in a strand shape. The obtained polymer was washed in boiling water for 1 hour and then dried. The logarithmic viscosity of the polymer was 0.97 dL / g. 10 g of polymer is dissolved in 30 ml of NMP, cast on a glass plate on a hot plate to a thickness of about 600 μm, heated at 80 ° C. for 1 hour, 120 ° C. for 1 hour, 150 ° C. for 1 hour, and then in an oven at 150 ° C. in a nitrogen atmosphere. And dried for 1 hour to peel the film from the glass plate.

  The obtained film was immersed in pure water at room temperature for 1 day, and then immersed in a 2 mol / L sulfuric acid aqueous solution for 2 hours. Thereafter, the film was washed with pure water until the washing water became neutral, and allowed to stand in the air and dried to obtain an ion exchange membrane. The obtained ion exchange membrane was evaluated as shown in Tables 1 and 2.

<Example 2>
The amount of S-DCDPS was 9.768 g (19.88 mmol), the amount of DCBN was 4.353 g (25.31 mmol), the amount of BP was 8.246 g (44.28 mmol), the amount of TCA was 0.1015 g (0 .57 mmol), and an ion exchange membrane was prepared and evaluated in the same manner as in Example 1 except that the amount of potassium carbonate was changed to 7.039 g (50.93 mmol).

  Moreover, the NMR spectrum of the obtained polymer is shown in FIG. FIG. 1 shows that not only a but also j is detected as the proton next to the sulfonic acid group, so that TCA is introduced into the polymer.

<Example 3>
The amount of S-DCDPS was 10.000 g (20.36 mmol), the amount of DCBN was 4.456 g (25.91 mmol), the amount of BP was 8.274 g (44.43 mmol), and the amount of potassium carbonate was 7.062 g ( 51.10 mmol), except that 0.1852 g (0.60 mmol) of 1,1,1-tris (4-hydroxyphenyl) ethane (abbreviation: THP) was used instead of TCA. The polymer was polymerized.

  As the viscosity of the solution increased during the polymerization, 10 mL of NMP was added. Thereafter, the precipitated molecular sieve was removed, and the resultant was precipitated in water in a strand shape. The obtained polymer was washed in boiling water for 1 hour and then dried.

  The logarithmic viscosity of the polymer was 1.99 dL / g. 6 g of polymer was dissolved in 34 g of NMP, cast on a glass plate on a hot plate to a thickness of about 600 μm, heated at 80 ° C. for 1 hour, 120 ° C. for 1 hour, 150 ° C. for 1 hour, and then in an oven at 150 ° C. in a nitrogen atmosphere. And dried for 1 hour to peel the film from the glass plate. The obtained film was immersed in pure water at room temperature for 1 day, and then immersed in a 2 mol / L sulfuric acid aqueous solution for 2 hours. Thereafter, the film was washed with pure water until the washing water became neutral, and allowed to stand in the air and dried to obtain an ion exchange membrane. The obtained ion exchange membrane was evaluated.

<Example 4>
The amount of DCBN was 8.170 g (47.50 mmol), the amount of BP was 12.135 g (65.17 mmol), the amount of potassium carbonate was 10.358 g (74.94 mmol), and the amount of THP was 0.2716 g (0. The polymer was polymerized in the same manner as in Example 1 except that THP was dissolved in 8 mL of NMP and added. As the viscosity of the solution increased during the polymerization, 20 mL of NMP was added. Thereafter, the precipitated molecular sieve was removed, and the resultant was precipitated in water in a strand shape. The obtained polymer was washed in boiling water for 1 hour and then dried. The logarithmic viscosity of the polymer was 2.64 dL / g. An ion exchange membrane was obtained from the obtained polymer in the same manner as in Example 3. The obtained ion exchange membrane was evaluated.

  Moreover, the NMR spectrum of the obtained polymer is shown in FIG. 2, and its enlarged view is shown in FIG. 2 and 3, since a signal derived from THP is detected at j, it can be seen that THP is introduced into the polymer.

<Example 5>
The procedure of Example 1 was repeated except that the amount of BP was changed to 11.645 g (62.53 mmol), the amount of potassium carbonate was changed to 9.939 g (71.91 mmol), and the amount of THP was changed to 0.5322 g (1.74 mmol). The polymer was polymerized. As the viscosity of the solution increased during the polymerization, 10 mL of NMP was added. Thereafter, the precipitated molecular sieve was removed, and the resultant was precipitated in water in a strand shape. The obtained polymer was washed in boiling water for 1 hour and then dried. The logarithmic viscosity of the polymer was 1.73 dL / g. An ion exchange membrane was obtained from the obtained polymer in the same manner as in Example 3. The obtained ion exchange membrane was evaluated.

  Moreover, the NMR spectrum of the obtained polymer is shown in FIG. FIG. 4 shows that a THP-derived signal is detected in j, so that THP is introduced into the polymer.

<Comparative Example 1>
An ion exchange membrane was prepared and evaluated in the same manner as in Example 1 using the following sulfonic acid group-containing polymer having a known structure.

<Comparative example 2>
An ion exchange membrane was prepared and evaluated in the same manner as in Example 1 using the following sulfonic acid group-containing polymer having a known structure.

<Comparative Example 3>
An ion exchange membrane was prepared and evaluated in the same manner as in Example 1 using the following sulfonic acid group-containing polymer having a known structure.

<Comparative example 4>
Various evaluations were performed on Nafion (trade name) 112, which is a commercially available ion exchange membrane.

<Comparative Example 5>
Various evaluations were performed on Nafion (trade name) 117 which is a commercially available ion exchange membrane.

<Comparative Example 6>
Polymerization was carried out in the same manner as in Example 2 except that the amount of TCA was changed to 0.2030 g (1.14 mmol), but after adding TCA, the heating temperature was raised again to 195 to 200 ° C. to react. However, the reaction solution gelled after 2 hours and no longer showed fluidity.

<Comparative Example 7>
Polymerization was conducted in the same manner as in Example 4 except that the amount of THP was changed to 0.8578 g (2.80 mmol). After adding THP, the reaction was carried out by increasing the heating temperature again to 195 to 200 ° C. However, the reaction solution gelled after 1 hour and no longer showed fluidity.

  Table 1 shows the evaluation results of the ion exchange membranes of Examples and Comparative Examples.

  As can be seen from Table 1, the ion exchange membranes of the examples are equivalent to or higher in proton conductivity and output voltage than the ion exchange membranes of Comparative Examples 1 to 3 made of a polymer having a known structure having a comparable ion exchange capacity. It can be seen that this is an excellent membrane that has a low methanol permeation rate and can achieve both high output and proton conductivity and methanol permeation-preventing properties. Moreover, it shows that the output voltage is superior to Nafion (trade name) 112 and 117, which are commercially available ion exchange membranes, and the methanol permeation-preventing property is greatly improved. From these facts, the sulfonic acid group-containing polymer of the present invention can greatly improve its characteristics when used in an ion exchange membrane for fuel cells, and contributes greatly to the industry.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

The polymer 10mg synthesized in Example 2 of the present invention was dissolved in deuterated dimethyl sulfoxide 0.6 mL, using a VARIAN Co. UNITY-500, is a diagram showing the ¹ H-NMR spectrum was measured at 70 ° C. . The polymer 10mg synthesized in Example 4 of the present invention was dissolved in deuterated dimethyl sulfoxide 0.6 mL, using a VARIAN Co. UNITY-500, is a diagram showing the ¹ H-NMR spectrum was measured at 70 ° C. . 10 mg of the polymer synthesized in Example 4 of the present invention was dissolved in 0.6 mL of deuterated dimethyl sulfoxide, and a spectrum obtained by enlarging a ¹ H-NMR spectrum measured at 70 ° C. using UNITY-500 manufactured by VARIAN was obtained. FIG. 10 mg of the polymer synthesized in Example 5 in the present invention was dissolved in 0.6 mL of deuterated dimethyl sulfoxide, and a spectrum obtained by enlarging the ¹ H-NMR spectrum measured at 70 ° C. using UNITY-500 manufactured by VARIAN was obtained. FIG.

Explanation of symbols

DMSO Signal derived from dimethyl sulfoxide in deuterated dimethyl sulfoxide, signal derived from water adsorbed on H ₂ O polymer, signal from aj polymer.

Claims (22)

A sulfonic acid group-containing polymer having a branched structure in which the structure represented by the following chemical formula (1) is linked to each other by a trivalent or tetravalent aromatic group (Ar ⁵ ).

In the chemical formula (1), X is an —S (═O) ₂ — group or —C (═O) — group, Y is an H atom or a monovalent cation, and Z ¹ and Z ² are independent of each other. And Ar ¹ and Ar ² are each independently a divalent aromatic group, and Ar ³ is an aromatic group represented by chemical formulas (2) to (5). Ar ⁴ is any of the aromatic groups represented by the following chemical formulas (2) to (7), and n and m are each independently 1 such that n + m is 5 or more. It is an integer above.

In chemical formula (6) and chemical formula (7), Y is an H atom or a monovalent cation. The number of moles (o) of the structure represented by the chemical formula (1) and the number of moles (p) of Ar ⁵ satisfy 0.7> p / o ≧ 0.2. The sulfonic acid group-containing polymer described in 1.   n + m is an integer greater than or equal to 10, The sulfonic acid group containing polymer of Claim 1 or 2 characterized by the above-mentioned. The sulfonic acid group-containing polymer according to claim 1, wherein Ar ¹ and Ar ² have a structure represented by the following chemical formula (8).

Ar ^5, characterized in that any one of structures represented by the following chemical formula (9) to (15), a sulfonic acid group-containing polymer according to claim 1.

  A polymer composition comprising the polymer according to claim 1.   An ion exchange resin comprising the polymer according to claim 1.   An ion exchange membrane comprising the polymer according to claim 1.   A fuel cell comprising the polymer according to any one of claims 1 to 5 in an electrode layer and / or a bonding layer between an electrode layer and an ion exchange membrane.   A membrane / electrode assembly comprising the polymer according to any one of claims 1 to 5 in an electrode layer and / or in a bonding layer between an electrode layer and an ion exchange membrane.   A membrane / electrode assembly obtained using the ion exchange membrane according to claim 8.   A fuel cell using the ion exchange membrane according to claim 8. An aromatic ether polymer and / or an aromatic thioether polymer having a branch in the molecule, wherein an aromatic dihalogen compound having a halogen group activated by an electron-withdrawing group is reacted with a phenol compound and / or a thiophenol compound. A manufacturing method comprising:
(A) An aromatic dihalogen compound having a halogen group activated by the electron-withdrawing group, a bisphenol compound and / or a bisthiophenol compound, the bisphenol compound and / or bisthio with respect to the aromatic dihalogen compound. A first step of obtaining a halogen group-terminated oligomer by reacting such that the molar ratio of the phenol compound is within the range of 0.80 to 0.99;
(B) A polyphenol compound having 3 or 4 phenolic hydroxyl groups and / or a polythiophenol compound having 3 or 4 thiophenol mercapto groups in the molecule is converted into a phenolic hydroxyl group and / or poly in the polyphenol compound. Reacts with the oligomer produced in the first step so that the number of moles of the halogen group in the oligomer produced in the first step is equal to or more than the number of moles of the thiophenolic mercapto group in the thiophenol compound. A second step of
A process for producing an aromatic ether polymer and / or an aromatic thioether polymer having a branch in the molecule.   14. The reaction according to claim 13, wherein the first step and the second step are performed by heating in an organic polar solvent in an inert gas atmosphere or air stream in the presence of an alkali metal salt. A method for producing an aromatic ether polymer and / or an aromatic thioether polymer having a branch in the molecule.   The ratio of the number of moles of the phenolic hydroxyl group of the polyphenol compound and / or the thiophenolic mercapto group of the polythiophenol compound to the number of moles of the halogen group in the oligomer obtained in the first step is 0.2-0. The method for producing an aromatic ether polymer and / or an aromatic thioether polymer having a branch in the molecule according to claim 13 or 14, wherein the method is within a range of .6. The aromatic dihalogen compound having a halogen group activated by the electron-withdrawing group includes any one of the compounds represented by the following chemical formula (16) or chemical formula (17). 15. The method for producing an aromatic ether polymer and / or an aromatic thioether polymer having a branch in the molecule according to any one of 15.

In chemical formula (16) and chemical formula (17), X is a halogen atom of F, Cl, I or Br, and Y is an alkali metal ion of Li, Na or K. The aromatic dihalogen compound having a halogen group activated by the electron-withdrawing group further includes any one of compounds represented by the following chemical formulas (18) to (21). 15. The method for producing an aromatic ether polymer and / or an aromatic thioether polymer having a branch in the molecule according to any one of 15.

In the chemical formulas (18) to (21), X is a halogen atom of F, Cl, I or Br. The said polyphenol compound or polythiophenol compound contains either of the compounds represented by following (22)-(28), It has a branch in the molecule | numerator in any one of Claims 13-17 characterized by the above-mentioned. A process for producing an aromatic ether polymer and / or an aromatic thioether polymer.

  The method for producing an aromatic ether polymer and / or an aromatic thioether polymer having a branch in a molecule according to any one of claims 13 to 18, wherein the bisphenol compound is 4,4'-dihydroxybiphenyl. .   The method for producing an aromatic ether polymer and / or aromatic thioether polymer having a branch in the molecule according to any one of claims 14 to 19, wherein the alkali metal salt is potassium carbonate or sodium carbonate. .   The intramolecular molecule according to any one of claims 14 to 20, wherein the organic polar solvent is N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide or sulfolane. A method for producing a branched aromatic ether polymer and / or aromatic thioether polymer.   The temperature during the heating is set in a range of 150 to 250 ° C, and the aromatic ether polymer and / or aromatic having a branch in the molecule according to any one of claims 14 to 21 A method for producing a thioether polymer.

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