JP2008019376A - Polymer composition containing sulfonic acid group, polymer electrolyte film, method for producing the same, polymer electrolyte film/electrode joint material and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer electrolyte film having excellent durability and penetration resistance to fuels such as methanol and good properties such as output and proton conductivity, a method for producing the film and a fuel cell produced by using the polymer electrolyte film. <P>SOLUTION: The polymer electrolyte film is produced from a polymer composition containing (A) a polymer containing a sulfonic acid group and having a structure expressed by chemical formula 1 in the molecule and (B) a compound expressed by chemical formula 2 by reacting the allyl group of the compound of chemical formula 2 by heat-treatment, etc. In the chemical formula 1, X is -S(=O)<SB>2</SB>- or -C(=O)-; Y is H or a univalent cation; Z<SP>1</SP>is O or S; Z<SP>2</SP>is any of O, S, -C(CH<SB>3</SB>)<SB>2</SB>-, -C(CF<SB>3</SB>)<SB>2</SB>-, -CH<SB>2</SB>- or cyclohexyl group; and n1 is an integer of ≥0. In the chemical formula 2, R is a bivalent organic group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sulfonic acid group-containing polymer composition, a polymer electrolyte membrane obtained from the polymer composition and a method for producing the same, and a polymer electrolyte membrane / electrode junction using the polymer composition and / or the polymer electrolyte membrane. And a fuel cell using the polymer electrolyte membrane / electrode assembly.

  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.

  As the polymer solid electrolyte membrane, a proton conductive ion exchange membrane 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, since fluorine is contained in the molecule, harmful hydrofluoric acid is mixed into the exhaust gas depending on the use conditions, and the environmental load during disposal is high.

  Perfluorocarbon sulfonic acid ion exchange membranes have well-balanced characteristics as electrolyte membranes for fuel cells, but hydrocarbon ion exchange membranes are actively developed to obtain better membranes in terms of cost and performance. Has been done.

  Many hydrocarbon ion exchange membranes use polymers in which ionic groups such as sulfonic acid groups are introduced into heat-resistant polymers such as polyimide and polysulfone. (For example, see Patent Document 1)

  Generally, in a hydrocarbon ion exchange membrane, it is necessary to introduce more ionic groups in order to develop proton conductivity equivalent to that of a perfluorocarbon sulfonic acid ion exchange membrane. However, when the amount of the ionic group is increased, the swellability by water is increased, which causes problems such as dimensional change and deterioration of physical characteristics during moisture absorption. For this reason, there are also hydrocarbon-based ion exchange membranes with improved polymer structure and reduced swelling. (For example, see Patent Document 2)

  However, improvement of the polymer structure may not be enough to suppress swelling in applications that require high proton conductivity. It is desirable that the polymer electrolyte membrane used in a fuel cell or the like is excellent not only in swelling resistance but also in various other characteristics such as proton conductivity.

  Further, when a polymer electrolyte membrane having a high swelling property is used in a fuel cell using a liquid such as methanol as a fuel, there is a problem that the permeability of a fuel such as methanol tends to increase. By improving the polymer structure, it is possible to suppress swelling and methanol permeability. However, there are cases where workability such as bondability with an electrode is lowered. For example, when joining an electrode catalyst layer to a polymer electrolyte membrane, a method of joining by applying heat and pressure is often used. This method is a method by which a polymer electrolyte membrane / electrode assembly can be easily obtained. In this case, from the viewpoint of workability, a polymer that can be bonded at a lower temperature is preferable, and it is better to use a proton conductive polymer having a low softening temperature. However, proton-conductive polymers with a low softening temperature and which are easy to process often have high swelling and methanol permeability, and when used in fuel cells, they have low durability and high output. There was a tendency that the problem of not being able to occur.

JP-T-2004-509224 JP 2004-179779 A

  The present invention has been made against the background of the problems of the prior art, and maintains the processability of the polymer electrolyte membrane when manufacturing the polymer electrolyte membrane / electrode assembly, and suppresses the swelling property of the polymer electrolyte membrane. Polymer electrolyte membrane excellent in durability and permeation suppression of fuel such as methanol, and excellent in characteristics such as output and proton conductivity, production method thereof, and polymer composition for obtaining the polymer electrolyte membrane Another object of the present invention is to provide a polymer electrolyte membrane / electrode assembly using the polymer composition and / or the polymer electrolyte membrane, and a fuel cell using the polymer electrolyte membrane / electrode assembly.

  As a result of intensive studies to solve the above problems, the present inventors have finally completed the present invention. That is, the present invention is as follows.

1. At least (A) the following chemical formula 1 in the molecule;

[In the chemical formula 1, X is a —S (═O) ₂ — group or —C (═O) — group, Y is H or a monovalent cation, Z ¹ is either an O or S atom, Z ² represents an O atom, an S atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group or a cyclohexyl group, and n1 represents an integer of 0 or more. To express. ]
The polymer composition characterized by including the sulfonic acid group containing polymer which has a structure represented by (B), and the compound represented by following Chemical formula 2. (B).

[In Chemical Formula 2, R represents a divalent organic group. ]

2. 2. The polymer composition according to 1 above, wherein the sulfonic acid group-containing polymer further contains a structure represented by Chemical Formula 3.

[In Chemical Formula 3, Ar ¹ is a divalent aromatic group, Z ³ is either an O or S atom, Z ⁴ is an O atom, an S atom, a —C (CH ₃ ) ₂ — group, —C Any one of (CF ₃ ) ₂ — group, —CH ₂ — group and cyclohexyl group, n2 represents an integer of 0 or more. ]

3. 3. The polymer composition as described in 2 above, wherein Ar ^{1 of the} sulfonic acid group-containing polymer is one or more groups selected from structures represented by the following chemical formulas 4 to 7.

4). 4. The polymer composition as described in 3 above, wherein Ar ^{1 of the} sulfonic acid group-containing polymer has a structure represented by Chemical Formula 7.

5. 2. The polymer composition as described in 1 above, wherein the sulfonic acid group-containing polymer has a sulfonic acid group content of 0.3 to 5.0 meq / g.

6). ^2. The polymer composition as described in 1 above, wherein Z ¹ and Z ² of the sulfonic acid group-containing polymer are both O atoms, and n1 is 3 or more.

7). ^3. The polymer composition as described in 2 above, wherein Z ³ and Z ⁴ of the sulfonic acid group-containing polymer are both O atoms, and n2 is 3 or more.

8). 2. The polymer composition according to 1 above, wherein the sulfonic acid group-containing polymer further has a structure represented by the following chemical formula 8.

[In Chemical Formula 8, X represents a —S (═O) ₂ — group or —C (═O) — group, Y represents H or a monovalent cation, and Z ⁵ represents either an O or S atom. . ]

9. 9. The polymer composition according to 8 above, wherein the sulfonic acid group-containing polymer further contains a structure represented by Chemical Formula 3.

10. 10. The polymer composition as described in 9 above, wherein the sulfonic acid group-containing polymer further has a structure represented by Chemical Formula 9.

[In Chemical Formula 9, Ar ² represents a divalent aromatic group, and Z ⁶ represents either an O or S atom. ]

11. 11. The polymer composition as described in 10 above, wherein Ar ^{2 of the} sulfonic acid group-containing polymer is one or more groups selected from structures represented by chemical formulas 4 to 7.

12 12. The polymer composition as described in 11 above, wherein Ar ^{2 of the} sulfonic acid group-containing polymer has a structure represented by Chemical Formula 7.

13. 9. The polymer composition as described in 8 above, wherein Z ¹ and Z ² of the sulfonic acid group-containing polymer are O or S atoms, and n1 is 1.

14 10. The polymer composition as described in 9 above, wherein Z ³ and Z ⁴ of the sulfonic acid group-containing polymer are O or S atoms, and n2 is 1.

15. The sulfonic acid group-containing polymer has at least repeating units represented by chemical formulas 1, 3, 8, and 9, respectively, and the mol% of each repeating unit and the mol% of other repeating structures satisfy Formulas 1 to 3. 2. The polymer composition as described in 1 above.

(In the above formula, n3 is the mol% of the structure represented by Chemical Formula 8, n4 is the mol% of the structure represented by Chemical Formula 1, n5 is the mol% of the structure represented by Chemical Formula 9, and n6 is the chemical formula. 3 represents the mol% of the structure represented by 3, and n7 represents the mol% of the other repeating structure.)

16. 2. The polymer composition as described in 1 above, wherein R of the compound represented by Chemical Formula 2 is one or more groups selected from the group consisting of structures represented by Chemical Formulas 10 to 12 below.

17. 2. The polymer composition according to 1 above, wherein R in the compound represented by Chemical Formula 2 is Chemical Formula 10.

18. 2. The polymer composition as described in 1 above, wherein the content of the compound having the structure represented by Chemical Formula 2 is 1 to 30% by weight.

19. 2. A polymer composition obtained from the polymer composition according to 1 above, wherein at least part of the allyl group of the compound having the structure represented by Chemical Formula 2 is an allyl group and / or sulfonic acid group-containing polymer of the compound; A polymer composition having a reacted bond.

20. 20. A polymer electrolyte membrane comprising the polymer composition as described in any one of 1 to 19 above.

21. A polymer electrolyte membrane / electrode assembly comprising the polymer composition according to any one of 1 to 19 in a polymer electrolyte and / or an electrode catalyst layer.

22. 22. A fuel cell using the polymer electrolyte membrane / electrode assembly according to 21 above.

23. A method for producing a polymer electrolyte membrane, comprising a step of heating a membrane formed from the polymer composition according to any one of 1 to 18 above at a temperature of 200 to 300 ° C.

24. 24. The process according to 23, wherein the sulfonic acid group of the sulfonic acid group-containing polymer is a metal salt before heating, and after the heating, the polymer is treated with an acid to convert the sulfonic acid group into an acid form. A method for producing a polymer electrolyte membrane.

  The polymer electrolyte membrane of the present invention improves durability by suppressing swelling without impairing the characteristics of the polymer electrolyte membrane such as processability and proton conductivity, and fuel such as methanol. It has an excellent point that the permeability can be suppressed.

  Hereinafter, the present invention will be described in detail.

  The polymer composition of the present invention includes at least a sulfonic acid group-containing polymer having a structure represented by Chemical Formula 1 and a compound represented by Chemical Formula 2. The ion conductivity is exhibited by the sulfonic acid group-containing polymer, and the swelling suppression effect is exhibited by the chemical formula 2. When the sulfonic acid group-containing polymer has the structure of Chemical Formula 1, it becomes possible to express excellent ion conductivity, and when used as a polymer electrolyte membrane, the bonding property with the electrode catalyst layer is improved. There are advantages.

  In the polymer composition, the content of the compound represented by Chemical Formula 2 is preferably in the range of 0.1 to 50% by weight, preferably 1 to 30% by weight with respect to the content of the sulfonic acid group-containing polymer. % Is more preferable, and the range of 5 to 25% by weight is more preferable. When the amount is less than 0.1% by weight, the durability improving effect is extremely small, which is not preferable. If it is more than 50% by weight, the proton conductivity at the time of the polymer electrolyte membrane is lowered, or the polymer electrolyte membrane becomes fragile, which is not preferable.

  The content of the sulfonic acid group-containing polymer in the polymer composition is preferably in the range of 1 to 99.9% by weight. When the composition is a solution, it is preferably in the range of 1 to 50% by weight, more preferably in the range of 5 to 40% by weight. When the composition is a molded body such as a film, it is preferably 50 to 99.9% by weight, more preferably 60 to 90% by weight, and 70 to 80% by weight. More preferably. When the content of the sulfonic acid group-containing polymer is less than 1% by weight, processability and proton conductivity are not sufficient, which is not preferable. When the content is more than 99.9% by weight, it is not preferable because a sulfonic acid group-containing polymer is substantially obtained and an improvement effect such as durability cannot be obtained.

In Chemical Formula 1, X is preferably a —S (═O) ₂ — group because solubility in a solvent is improved. It is preferable that X is a —C (═O) — group because the softening temperature of the polymer can be lowered to enhance the bonding property with the electrode, or the photocrosslinking property can be imparted to the electrolyte membrane. When used as a polymer electrolyte membrane, Y is preferably an H atom. However, if Y is an H atom, it is easily decomposed by heat or the like. Therefore, during processing such as manufacturing of an electrolyte membrane, Y is set as an alkali metal salt such as Na or K, and Y is converted to H atom by acid treatment after processing. A polymer electrolyte membrane can also be obtained by conversion. Z ¹ is preferably O since it has advantages such as less coloring of the polymer and easy availability of raw materials. Z ¹ is preferably S because oxidation resistance is improved. n1 is preferably in the range of 0 to 30, and when n1 is 3 or more, a plurality of units different in n1 may be included. When n1 is 1 or more, Z ² represents an O atom, an S atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group, a cyclohexyl group, and an O atom S atoms are preferred because the bondability is further improved. n1 When in the case of 3 or more is Z ² is O atom, preferably in particular for improving bondability between the electrode catalyst layer in the case of the polymer electrolyte membrane.

  R in the compound represented by Chemical Formula 2 represents a divalent organic group and is not particularly limited, but is preferably a structure represented by Chemical Formulas 2 to 4. Among these, a structure represented by Chemical Formula 2 is preferable from the viewpoint of durability.

It is preferable that the sulfonic acid group-containing polymer further contains a structure represented by the chemical formula 3 in addition to the structure of the chemical formula 1, since the bondability with the electrode is further improved when a polymer electrolyte membrane is formed. Z ³ is preferably O, because it has advantages such as less coloring of the polymer and easy availability of raw materials. Z ³ is preferably S because oxidation resistance is improved. n2 is preferably in the range of 0 to 30, and when n2 is 3 or more, a plurality of units different in n2 may be included. When n2 is 1 or more, Z ⁴ represents an O atom, an S atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group, a cyclohexyl group, and an O atom S atoms are preferred because the bondability is further improved. n2 When the case 3 or more is Z ⁴ is O atom, preferably in particular for improving bondability between the electrode catalyst layer in the case of the polymer electrolyte membrane.

  The molar ratio of the structure represented by Chemical Formula 1 and the structure represented by Chemical Formula 3 is preferably in the range of 5:95 to 90:10. The molar ratio of 5:95 means that the number of moles of the structure represented by Chemical Formula 3 is 95 when the number of moles of the structure represented by Chemical Formula 1 is 5. If the structure represented by Chemical Formula 1 is less than the molar ratio of 5:95, the ionic conductivity of the polymer electrolyte membrane is lowered, which is not preferable. When the structure represented by the chemical formula 1 is larger than the molar ratio of 90:10, the swelling property of the polymer electrolyte membrane becomes too large or becomes water-soluble. More preferably, it is the range of 10: 90-70: 30.

  When used as a polymer electrolyte membrane of a fuel cell using hydrogen as a fuel, the molar ratio between the structure represented by Chemical Formula 1 and the structure represented by Chemical Formula 3 is in the range of 30:70 to 80:20. It is preferable that it is in the range of 40:60 to 70:30.

  When used as a polymer electrolyte membrane of a fuel cell using a liquid such as methanol as a fuel, the molar ratio between the structure represented by Chemical Formula 1 and the structure represented by Chemical Formula 3 is 7:93 to 50:50. The range is preferable, and the range of 10:90 to 40:60 is more preferable. When the structure represented by the chemical formula 1 is larger than the molar ratio of 50:50, the fuel permeability may be increased when the polymer electrolyte membrane is formed, which is not preferable. If the structure represented by Chemical Formula 1 is less than the molar ratio of 7:93, it is not preferable because the ionic conductivity of the polymer electrolyte membrane decreases and the resistance increases.

Ar ¹ in Chemical Formula 3 is preferably a divalent aromatic group having an electron-withdrawing group. Examples of the electron-withdrawing group include a sulfone group, a sulfonyl group, a sulfonic acid group, a sulfonic acid ester group, a sulfonic acid amide group, a sulfonic acid imide group, a carboxyl group, a carbonyl group, a carboxylic acid ester group, a cyano group, a halogen group, Although a trifluoromethyl group, a nitro group, etc. can be mentioned, it is not limited to these, What is necessary is just a well-known arbitrary electron withdrawing group.

A preferable structure of Ar ¹ is a structure represented by chemical formulas 4 to 7. The structure of Chemical Formula 4 is preferable because it can increase the solubility of the polymer. The structure of Chemical Formula 5 is preferable because it lowers the softening temperature of the polymer to increase the bondability with the electrode or impart photocrosslinkability. The structure of Chemical Formula 6 or 7 is preferable because the swelling of the polymer can be reduced, and the structure of Chemical Formula 7 is more preferable. Among the chemical formulas 4 to 7, the structure of the chemical formula 7 is most preferable.

  The sulfonic acid group content in the sulfonic acid group-containing polymer of the present invention is preferably in the range of 0.1 to 10 meq / g, more preferably 0.3 to 5.0 meq / g, 0.5 to More preferably, it is 4 meq / g. When it is 0.1 meq / g or less, the ionic conductivity when the polymer electrolyte membrane is formed is too low, which is not preferable. As the sulfonic acid group content increases, the ionic conductivity increases. However, if it exceeds 10 meq / g, the polymer becomes water-soluble or the swelling property becomes remarkably large, which is not preferable.

In addition to the structure represented by the chemical formula 1, the sulfonic acid group-containing polymer in the present invention further has a structure represented by the chemical formula 8, which improves the shape stability of the membrane when used as a polymer electrolyte membrane. Since it can raise, it is preferable. In Chemical Formula 8, X is preferably a —S (═O) ₂ — group because solubility in a solvent is improved. It is preferable that X is a —C (═O) — group because the softening temperature of the polymer can be lowered to enhance the bonding property with the electrode, or the photocrosslinking property can be imparted to the electrolyte membrane. When used as a polymer electrolyte membrane, Y is preferably an H atom. However, if Y is an H atom, it is easily decomposed by heat or the like. Therefore, during processing such as manufacturing of an electrolyte membrane, Y is set as an alkali metal salt such as Na or K, and Y is converted to H atom by acid treatment after processing. A polymer electrolyte membrane can also be obtained by conversion. Z ⁵ is preferably O, because there are advantages such as little polymer coloring and easy availability of raw materials. Z ¹ is preferably S because oxidation resistance is improved.

The sulfonic acid group-containing polymer in the present invention preferably further has a structure represented by Chemical Formula 3 in addition to the structures represented by Chemical Formulas 1 and 8. In this case, when Z ¹ and Z ² are O or S atoms and n1 is 1, the bonding property with the electrode catalyst layer and the morphological stability of the membrane in the case of a polymer electrolyte membrane are improved. This is preferable. Further, when Z ³ and Z ⁴ are O or S atoms and n2 is 1, the bonding property with the electrode catalyst layer and the morphological stability of the membrane in the case of a polymer electrolyte membrane are further improved. Therefore, it is preferable.

When the sulfonic acid group-containing polymer in the present invention further has a structure represented by the chemical formula 9 in addition to the structures represented by the chemical formulas 1, 3, and 8, the electrode catalyst can be obtained as a polymer electrolyte membrane. It is more preferable because the bondability with the layer and the form stability of the film can be greatly improved. Z ⁶ in the chemical formula 9 is preferably O, since there are advantages such as little polymer coloring and easy availability of raw materials. Z ⁶ is preferably S because oxidation resistance is improved. Ar ² in Chemical Formula 9 is preferably a divalent aromatic group having an electron-withdrawing group. Examples of the electron-withdrawing group include a sulfone group, a sulfonyl group, a sulfonic acid group, a sulfonic acid ester group, a sulfonic acid amide group, a sulfonic acid imide group, a carboxyl group, a carbonyl group, a carboxylic acid ester group, a cyano group, a halogen group, Although a trifluoromethyl group, a nitro group, etc. can be mentioned, it is not limited to these, What is necessary is just a well-known arbitrary electron withdrawing group.

A preferable structure of Ar ² is a structure represented by chemical formulas 4 to 7. The structure of Chemical Formula 4 is preferable because it can increase the solubility of the polymer. The structure of Chemical Formula 5 is preferable because it lowers the softening temperature of the polymer to increase the bondability with the electrode or impart photocrosslinkability. The structure of Chemical Formula 6 or 7 is preferable because the swelling of the polymer can be reduced, and the structure of Chemical Formula 7 is more preferable. Among the chemical formulas 4 to 7, the structure of the chemical formula 7 is most preferable.

  When the sulfonic acid group-containing polymer in the present invention has all the repeating units represented by the chemical formulas 1, 3, 8, and 9, the mol% of each repeating unit and the mol% of other repeating structures are It is preferable to satisfy Formulas 1-3.

  When (n3 + n4 + n5 + n6) / (n3 + n4 + n5 + n6 + n7) is smaller than 0.9, good characteristics cannot be obtained when a polymer electrolyte membrane is obtained, which is not preferable. More preferred is a range of 0.95 to 1.0.

  When (n3 + n4) / (n3 + n4 + n5 + n6) is smaller than 0.05, sufficient ion conductivity cannot be obtained when a polymer electrolyte membrane is obtained, which is not preferable. On the other hand, if it is larger than 0.9, the swellability of the polymer electrolyte membrane is remarkably increased, which is not preferable. A more preferred range is from 0.1 to 0.7.

  When used as a polymer electrolyte membrane of a fuel cell using hydrogen as a fuel, (n3 + n4) / (n3 + n4 + n5 + n6) is preferably in the range of 0.3 to 0.8, and in the range of 0.4 to 0.7. It is more preferable that If it is less than 0.3, it is not preferable because sufficient output cannot be obtained, and if it is more than 0.8, swelling may be remarkably increased.

  When used as a polymer electrolyte membrane of a fuel cell using a liquid such as methanol as a fuel, (n3 + n4) / (n3 + n4 + n5 + n6) is preferably in the range of 0.07 to 0.5, preferably 0.1 to 0.00. A range of 4 is more preferable. If it is larger than 0.5, the fuel permeability may increase, which is not preferable. If it is smaller than 0.07, the ion conductivity is lowered and the resistance is increased, which is not preferable.

  When (n4 + n6) / (n3 + n4 + n5 + n6) is less than 0.01, it is not preferable because the bonding property with the electrode catalyst layer is lowered when a polymer electrolyte membrane is formed. If it is greater than 0.95, the swellability of the polymer electrolyte membrane may become too large, which is not preferable. 0.05 to 0.8 is a more preferable range. When used for a polymer electrolyte membrane of a fuel cell using hydrogen as a fuel, it is preferably in the range of 0.05 to 0.4, and used for a polymer electrolyte membrane of a fuel cell using a liquid such as methanol as a fuel. In some cases, a range of 0.4 to 0.8 is more preferable.

  Preferred examples of the sulfonic acid group-containing polymer in the present invention are shown below, but the present invention is not limited thereto, and a polymer having an arbitrary structure within the scope of the claims of the present invention can be used. In the following specific examples, n, n ′, n ″, m, m ′, m ″, o, o ′, o ″, p, p ′, p ″, f each independently represents an integer of 1 or more. .

  In a more preferred embodiment of the present invention, at least a part of the allyl group of the compound having the structure represented by the chemical formula 2 has a bond reacted with the allyl group and / or sulfonic acid group-containing polymer of the compound. A polymer composition, a polymer electrolyte membrane obtained from the polymer composition, a polymer electrolyte membrane / electrode assembly, and a fuel cell. The allyl group may react only with the allyl group. Moreover, you may react with the sulfonic acid group containing polymer. Whether or not the allyl group is reacted can be detected by any known means. For example, using NMR, if the peak area derived from an allyl group decreases and the peak area of an alkyl group as a reaction product increases, it can be confirmed that a reaction has occurred between the allyl groups. In addition, it can also be confirmed by a decrease in the peak area of the carbon double bond when an IR spectrum is measured. At the same time, if there is no change in the NMR spectrum of the polymer, it can be determined that there is no reaction between the allyl group and the polymer.

  The method of reacting the allyl group of the compound having the structure represented by Chemical Formula 2 is not particularly limited, and examples thereof include heat treatment and irradiation with an electron beam or radiation. Among these, heat treatment is preferable because it can be easily performed. The heating temperature is preferably in the range of 200 to 300 ° C, and more preferably in the range of 240 to 270 ° C. The heating time is not particularly limited, but is preferably in the range of 0.1 to 10 hours, and more preferably in the range of 0.5 to 5 hours. When the heating temperature is lower than 200 ° C., the reaction does not sufficiently occur, which is not preferable. When the heating temperature is higher than 300 ° C., the sulfonic acid group-containing polymer may be decomposed, which is not preferable. Further, if the heating time is shorter than 0.1 hour, it may not be possible to sufficiently heat and the reaction may be insufficient, and if it is longer than 10 hours, the decomposition of the sulfonic acid group-containing polymer or high This is not preferred because problems such as deformation and breakage of the molecular electrolyte membrane and composition may occur.

  When heat treatment is performed, heating is preferably performed in an atmosphere of an inert gas such as nitrogen or argon, but can also be performed in an atmosphere containing a very small amount of oxygen. Heating in an atmosphere containing a large amount of oxygen, such as air, is not preferable because allyl groups are oxidized and the reaction may not proceed. When heat treatment is performed, it is preferably performed by fixing with a frame or a tenter. If heat treatment is performed without fixing, it is not preferable because it causes deformation, wrinkling, and breakage of the composition and the polymer electrolyte membrane.

  When electron beam or radiation irradiation is performed, it is preferably performed in an inert gas atmosphere such as argon. When processing, it is preferable to fix by a frame or a tenter.

  The polymer electrolyte membrane in the present invention can have any thickness, but if it is 10 μm or less, it becomes difficult to satisfy the predetermined characteristics, and therefore 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.

  The polymer electrolyte membrane in the present invention may contain other polymers. Examples of such 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 polymethacrylic acid. Acrylate resins such as esters, polymethyl acrylate, polyacrylates, polyacrylic acid resins, polymethacrylic acid resins, polyethylene, polypropylene, various polyolefins including polystyrene and diene polymers, polyurethane resins, cellulose acetate Cellulose resins such as ethyl cellulose, polyarylate, aramid, polycarbonate, polyphenylene sulfide, polyphenylene oxide, polysulfone, polyether Thermal curing of aromatic polymers such as sulfone, polyetheretherketone, polyetherimide, polyimide, polyamideimide, 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 preferable combination for improving the polymer dimensionality, and when a sulfonic acid group is further introduced into these basic polymers, The processability of the composition becomes more preferable. The polymer electrolyte membrane of the present invention can be used as 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, and an antifoaming agent. Various additives such as an agent, a dispersant, and a polymerization inhibitor may be included.

  The polymer electrolyte membrane of the present invention can be obtained from the polymer composition 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, immersion in a compound non-solvent that can be mixed with a solvent that dissolves the compound, or the like. 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. The timing of reacting the allyl group of the compound having the structure represented by Chemical Formula 2 may be before or after molding, but is preferably performed after molding from the viewpoint of workability.

  The most preferable method for forming the polymer electrolyte membrane of the present invention is casting from a solution, and the polymer electrolyte membrane can be obtained by removing the solvent from the cast solution as described above. 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 polymer electrolyte 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 less than 10 μm, the form as a polymer electrolyte membrane tends to be not maintained, and if it is more 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 by the amount and concentration of the solution by making the thickness constant using an applicator, a doctor blade or the like, or making the 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. In the processing, when heating is involved, it is preferable that the sulfonic acid group in the sulfonic acid group-containing polymer forms a salt with a cation because stability is improved. However, for use as a polymer electrolyte membrane, it can be converted to free sulfonic acid by an appropriate acid treatment. In this case, it is effective to immerse the membrane in an aqueous solution of sulfuric acid, hydrochloric acid, etc. with or without heating.

  One of the preferred methods for obtaining the polymer electrolyte membrane of the present invention is to prepare a membrane from the polymer composition of the present invention in which the allyl group of the compound represented by Chemical Formula 2 is in an unreacted state. This is a method of reacting the allyl group on the obtained film. Means for reacting the allyl group are described above. A more preferable method is to prepare a membrane in a state in which the sulfonic acid group of the sulfonic acid group-containing polymer in the polymer composition forms a salt, react the allyl group on the prepared membrane, and then perform sulfonic acid group treatment by acid treatment. In this method, the sulfonic acid group of the containing polymer is returned to the acid.

  The membrane / electrode assembly of the present invention can be obtained by bonding the polymer electrolyte 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, a method of applying an adhesive to the electrode surface and bonding the polymer electrolyte membrane and the electrode, or a polymer electrolyte membrane and the electrode There is a method of heating and pressurizing. A method in which an adhesive mainly composed of the polymer composition of the present invention is applied to the electrode surface for adhesion is preferable, and the allyl group of the compound represented by Chemical Formula 2 in the polymer composition is not reacted. It is more preferable to use a product. This is because the adhesion between the polymer electrolyte membrane and the electrode is improved, and it is considered that the proton conductivity of the polymer electrolyte membrane is less impaired. Since the polymer electrolyte membrane and the polymer composition of the present invention have an appropriate softening temperature, they are particularly suitable for a method of joining a polymer electrolyte membrane and an electrode by pressure heating.

  The fuel cell of the present invention can be produced using the polymer electrolyte membrane or the polymer electrolyte membrane / electrode assembly of the present invention. The fuel cell of the present invention includes, for example, an oxygen electrode, a fuel electrode, a polymer electrolyte membrane sandwiched between the electrodes, an oxidant flow path provided on the oxygen electrode side, and a fuel electrode side. The fuel flow path is provided. A fuel cell stack can be obtained by connecting such unit cells with a conductive separator.

  The polymer electrolyte membrane of the present invention is suitable for a polymer electrolyte fuel cell. Since the polymer electrolyte membrane of the present invention has low swellability, it is suitable for a fuel cell using a liquid as a fuel, such as a direct methanol fuel cell using methanol as a fuel. In addition, the polymer electrolyte membrane of the present invention has high durability because it has excellent bonding properties between the polymer electrolyte membrane and the electrode, and not only fuel cells that use liquids such as direct methanol fuel cells but also hydrogen as fuel. Suitable for fuel cells. Moreover, it can be used suitably also for the fuel cell which uses other substances, such as a dimethyl ether, hydrogen, formic acid, as a fuel, and can be used for arbitrary uses well-known as polymer electrolyte 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 by c (ta is the number of seconds for dropping the sample solution, tb is the number of seconds for dropping only the solvent, and c is 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 probe for self-made measurement (made of tetrafluoroethylene resin), and water at 25 ° C. or constant temperature and humidity at 80 ° C. and 95%. The sample was held in the tank, and the impedance between the platinum wires 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. The distance between the electrodes was set to 1.5 cm in water at 25 ° C. and 1 cm at 80 ° C. and 95%.
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 between H-type cells, 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.

Electricity generation evaluation of hydrogen-fueled fuel cell (PEFC): 20% Nafion (registered trademark) solution made by DuPont, commercially available 40% Pt catalyst-supported carbon (Tanaka Kikinzoku Kogyo Co., Ltd. Fuel Cell Catalyst TEC10V40E) and a small amount After adding ultrapure water and isopropanol, the mixture was stirred until uniform to prepare a catalyst paste. This catalyst paste was uniformly applied to Toray carbon paper TGPH-060 so that the amount of platinum deposited was 0.5 mg / cm ² and dried to prepare a gas diffusion layer with an electrode catalyst layer. An ion exchange membrane is sandwiched between the gas diffusion layers with the electrode catalyst layer so that the electrode catalyst layer is in contact with the membrane, and the membrane is pressurized and heated at 130 ° C. and 2 MPa for 3 minutes by a hot press method. -It was set as the electrode assembly. The joined body was assembled in an evaluation fuel cell FC25-02SP manufactured by Electrochem, and hydrogen and air humidified at 75 ° C. were supplied to the anode and the cathode at a cell temperature of 80 ° C., and the power generation characteristics were evaluated. The output voltage at a current density of 0.5 A / cm ² immediately after the start was taken as the initial characteristics. Moreover, as durability evaluation, continuous operation was performed on said conditions, measuring an open circuit voltage at the rate of once per hour. The time when the open circuit voltage decreased by 10% or more from the value immediately after the start was defined as the endurance time. Durability evaluation was performed with 1000 hours as the upper limit.

Power generation evaluation of direct methanol fuel cell (DMFC): After adding a small amount of ultrapure water and isopropyl alcohol to Pt / Ru catalyst-supported carbon (TEC61E54, Tanaka Kikinzoku Kogyo Co., Ltd.) and moistening, 20% Nafion (DuPont) (Registered trademark) solution (product number: SE-20192) was added so that the weight ratio of Pt / Ru catalyst-carrying carbon to Nafion 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 Pt catalyst-supporting carbon (Tanaka Kikinzoku Kogyo Co., Ltd. TEC10V40E) and moistening, a 20% Nafion (registered trademark) solution (product number: SE-20192) manufactured by DuPont. Then, the Pt catalyst-carrying carbon and Nafion were added in a weight ratio of 2.5: 1 and stirred to prepare a cathode catalyst paste. 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 160 ° 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). The 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 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 0.02 A / cm ² and the resistance value measured by the current interruption method were measured.

Electrode bondability: After the evaluation of power generation of the DMFC, “◯” was given when no peeling was observed between the polymer electrolyte membrane and the electrode catalyst layer, and “X” was given when peeling occurred.

Swellability: After a 5 cm square square polymer electrolyte membrane was immersed in pure water at 80 ° C. for 1 hour, water on the surface was quickly removed and placed in a sealed container, and the weight of the hygroscopic membrane was measured. Thereafter, the membrane was dried under reduced pressure at 100 ° C. for 1 hour, then placed in a sealed container, and the weight of the dried membrane was measured. The water content was determined by subtracting the weight of the hygroscopic film from the weight of the dry film, and the weight% of the water content relative to the weight of the dry film was defined as swellability.

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.

Softening temperature: While heating an acid-type film having a width of 5 mm at a chuck width of 10 mm from 50 ° C. to 250 ° C. at a rate of 2 ° C./min, a dynamic strain of 10 Hz was applied to give dynamic viscoelasticity, Rhegel E-4000 ( Measured using Toki Sangyo Co., Ltd. The temperature at the inflection point at which E ′ greatly decreased was defined as the softening temperature.

<Synthesis Example 1>
Sodium 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone (abbreviation: S-DCDPS) 31.212 g (0.06354 mol), 2,6-dichlorobenzonitrile (abbreviation: DCBN) 18.609 g (0 .1082 mol), terminal hydroxyl group-containing phenylene ether oligomer (Dainippon Ink & Chemicals, Inc. SPECIANOL DPE-PL; in the following chemical formula 17, n is a mixture containing 1 to 8 components, and the average value of n is 5 Some) (abbreviation: DPE) 94.421 g (0.1717 mol), potassium carbonate 26.107 g (0.1889 mol), N-methyl-2-pyrrolidone (abbreviation: NMP) 439.07 g in a 1000 ml four-necked flask Weighed and flushed with nitrogen. Heating was performed while stirring, and the reaction solution was allowed to react for 8 hours so that the temperature of the reaction solution became 190 to 200 ° C. Then, it cooled to room temperature and poured the reaction solution into water, and precipitated in strand form. The resulting polymer was washed twice with room temperature water and twice with boiling water, and then dried at 100 ° C.

<Synthesis Example 2>
S-DCDPS 26.323 g (0.05358 mol), DCBN 19.586 g (0.1139 mol), DPE 64.452 g (0.1172 mol), 4,4′-dihydroxydiphenyl ether 10.158 g (0.05023 mol), potassium carbonate A polymer was obtained in the same manner as in Synthesis Example 1 using 25.458 g (0.1842 mol) and 361.03 g of NMP.

<Synthesis Example 3>
S-DCDPS 31.136 g (0.06338 mol), DCBN 61.7979 g (0.3592 mol), 4,4′-biphenol (abbreviation: BP) 19.670 g (0.1056 mol), 4,4′-dihydroxydiphenyl sulfide (Abbreviation: BPS) 69.170 g (0.3169 mol), potassium carbonate 64.239 g (0.4648 mol), and NMP 432.511 g were used, and a polymer was obtained in the same manner as in Synthesis Example 1.

<Synthesis Example 4>
S-DCDPS 30.54 g (0.06118 mol), DCBN 47.940 g (0.2787 mol), BP 15.822 g (0.08497 mol), BPS 55.639 g (0.2549 mol), 51.673 g (0. 3739 mol) and 374.014 g of NMP, and a polymer was obtained in the same manner as in Synthesis Example 1.

<Synthesis Example 5>
S-DCDPS 28.512 g (0.05804 mol), DCBN 39.934 g (0.2322 mol), BP 13.310 g (0.07255 mol), BPS 47.506 g (0.2177 mol), potassium carbonate 44.119 g (0. 3192 mol) and 324.900 g of NMP, a polymer was obtained by the same operation as in Synthesis Example 1.

<Synthesis Example 6>
S-DCDPS 63.215 g (0.1287 mol), DCBN 28.171 g (0.1638 mol), BP 49.013 g (0.2632 mol), BPS 6.384 g (0.02925 mol), potassium carbonate 44.463 g (0. 3217 mol) and NMP 376.370 g were used, and a polymer was obtained by the same operation as in Synthesis Example 1.

<Synthesis Example 7>
S-DCDPS 73.792 g (0.1502 mol), DCBN 32.885 g (0.1912 mol), BP 55.942 g (0.3004 mol), BPS 7.452 g (0.03414 mol), potassium carbonate 51.902 g (0. 3755 mol) and 376.329 g of NMP, a polymer was obtained by the same operation as in Synthesis Example 1.

<Synthesis Example 8>
S-DCDPS 80.156 g (0.1632 mol), DCBN 30.405 g (0.1768 mol), BP 51.272 g (0.2754 mol), BPS 11.130 g (0.05099 mol), potassium carbonate 51.680 g (0. 3739 mol), 10- (2,5-dihydroxyphenyl) -9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide (manufactured by Sanko Co., Ltd., HCA-HQ) (abbreviation: HCQ) 4 .409 g (0.01360 mol) and NMP 387.234 g were used, and a polymer was obtained in the same manner as in Synthesis Example 1.

<Synthesis Example 9>
S-DCDPS 82.451 g (0.1678 mol), DCBN 19.247 g (0.1119 mol), BP 44.796 g (0.2406 mol), BPS 6.106 g (0.02797 mol), potassium carbonate 42.528 g (0. 3077 mol), 3.628 g (0.01190 mol) of HCQ, and 344.897 g of NMP, and a polymer was obtained in the same manner as in Synthesis Example 1.

<Synthesis Example 10>
S-DCDPS 30.135 g (0.06134 mol), DCBN 42.207 g (0.2454 mol), BP 13.707 g (0.07361 mol), 4,4′-thiobis (benzenethiol) 58.370 g (0.2331 mol) , 46.631 g (0.3374 mol) of potassium carbonate and 366.159 g of NMP were used to obtain a polymer by the same operation as in Synthesis Example 1.

<Synthesis Example 11>
S-DCDPS 31.234 g (0.06358 mol), DCBN 46.624 g (0.2711 mol), BP 12.463 g (0.06693 mol), 2,2-bis (4-hydroxyphenyl) propane 61.115 g (0. 2677 mol), 50.875 g (0.3681 mol) of potassium carbonate, and 381.102 g of NMP, and a polymer was obtained by the same operation as in Synthesis Example 1.

<Synthesis Example 12>
S-DCDPS 30.941 g (0.06298 mol), DCBN 34.307 g (0.1995 mol), BP 11.728 g (0.06298 mol), 2,2-bis (4-hydroxyphenyl) hexafluoropropane 67.061 g ( 0.1995 mol), potassium carbonate 39.898 g (0.2887 mol), and NMP 374.703 g were used, and a polymer was obtained in the same manner as in Synthesis Example 1.

<Synthesis Example 13>
S-DCDPS 31.743 g (0.06462 mol), DCBN 44.459 g (0.2585 mol), BP 14.439 g (0.07754 mol), 1,1-bis (4-hydroxyphenyl) cyclohexane 65.892 g (0. 2455 mol), potassium carbonate 49.119 g (0.3554 mol), and NMP 398.919 g were used, and a polymer was obtained in the same manner as in Synthesis Example 1.

<Synthesis Example 14>
30.120 g (0.06462 mol) of S-DCDPS, 51.492 g (0.2994 mol) of DCBN, 67.159 g (0.3607 mol) of BP, 54.832 g (0.3967 mol) of potassium carbonate, and 314.926 g of NMP were used. A polymer having a structure represented by the chemical formula 18 was obtained in the same manner as in Synthesis Example 1.

<Examples 1 to 13>
For each of the polymers synthesized in Synthesis Examples 1 to 9, 10 g of a polymer, 1 g of a compound represented by the following chemical formula 19 (MANI manufactured by Maruzen Petrochemical Co., Ltd.) (abbreviation: BAM), and 30 g of NMP were placed in a 100 cc flask, and nitrogen was added. It stirred for 5 hours, heating at 50 degreeC under atmosphere, and the transparent uniform solution was obtained. The obtained solution was cast on a glass plate with a thickness of 300 μm using an applicator and heated at 80 ° C. for 30 minutes, then at 120 ° C. for 30 minutes, and at 150 ° C. for 30 minutes to evaporate NMP. Thereafter, the film was immersed in water, the film was peeled off from the glass plate, the surface water was removed with a filter paper, and then fixed to a stainless steel frame (30 × 20 cm). The fixed film was heated at 250 ° C. for 1 hour in a nitrogen atmosphere, allowed to cool to room temperature, and removed from the frame. The removed film was removed from the portion in contact with the frame, immersed in water at room temperature for 12 hours, immersed in 2M sulfuric acid at room temperature for 30 minutes, and further immersed in another 2M sulfuric acid at room temperature for 30 minutes. Thereafter, the membrane was washed with water until the pH of the washing solution reached 5 or higher. After the surface of the membrane has been removed with filter paper, the washed membrane is sandwiched between new dry filter papers, and further sandwiched between glass plates with a thickness of 1 cm. A membrane was obtained. The obtained polymer electrolyte membrane was evaluated.

<Example 14>
A polymer electrolyte membrane was obtained in the same manner as in Examples 1 to 13, except that 10 g of the polymer synthesized in Synthesis Example 5, 2 g of BAM, and 30 g of NMP were used. The obtained polymer electrolyte membrane was evaluated.

<Example 15>
A polymer electrolyte membrane was obtained in the same manner as in Examples 1 to 13 except that 10 g of the polymer synthesized in Synthesis Example 5 and 0.5 g of BAM and 30 g of NMP were used. The obtained polymer electrolyte membrane was evaluated.

<Comparative Examples 1-13>
About each polymer synthesize | combined in the synthesis examples 1-13, 10 g of polymers and 30 g of NMP were used, BAM was not added, and it heat-fixed to the stainless steel frame, and it was the same operation as Examples 1-13 As a result, a polymer electrolyte membrane was obtained. The obtained polymer electrolyte membrane was evaluated.

<Comparative example 14>
About the polymer synthesize | combined in the synthesis example 5, the polymer electrolyte membrane was obtained by operation similar to Examples 1-13 except having used polymer 10g and NMP30g and having not added BAM. The obtained polymer electrolyte membrane was evaluated.

<Comparative Example 15>
A polymer electrolyte membrane was obtained in the same manner as in Examples 1 to 13 except that 10 g of the polymer synthesized in Synthesis Example 14 and 0.5 g of BAM and 30 g of NMP were used. The obtained polymer electrolyte membrane was evaluated.

<Comparative Example 16>
Evaluation was performed on Nafion (registered trademark) 112, which is a commercially available polymer electrolyte membrane.

<Comparative Example 17>
Evaluation was performed on Nafion (registered trademark) 117, which is a commercially available polymer electrolyte membrane.

  The evaluation results are shown in Table 1.

  The polymer electrolyte membranes of the present invention shown in Examples 1 to 5 and 10 to 13 can be suitably used for a fuel cell using a liquid as a fuel, such as a direct methanol fuel cell (DMFC). The polymer electrolyte membranes of the present invention shown in Examples 1 to 5 and 10 to 13 are compared with the polymer electrolyte membranes of Comparative Examples 1 to 5 and 10 to 13 that do not include a compound having a structure represented by Chemical Formula 2, It can be seen that although the resistance of the membrane is slightly increased, the methanol permeability coefficient is reduced, indicating a higher output voltage. Further, in the polymer electrolyte membrane of Comparative Example 14, which is a membrane obtained by heat-treating the polymer electrolyte membrane of Comparative Example 5, although the methanol permeability coefficient is decreased by the heat treatment, the degree is small and the output voltage is lower than that of the Example. Can only be obtained. Further, the polymer electrolyte membrane of Comparative Example 15 in which the sulfonic acid group-containing polymer is outside the scope of the present invention is not inferior in methanol permeability as compared with the electrolyte membrane of Example 5, but the membrane resistance is remarkably large. Only very low output voltage is obtained. Therefore, by using a sulfonic acid group-containing polymer within the scope of the present invention whose softening temperature is not too high, not only the methanol permeability is small, but also the bonding property with the electrode catalyst layer is good, and the polymer electrolyte It can be seen that a polymer electrolyte membrane / electrode assembly excellent in workability when producing a membrane / electrode assembly can be obtained. In contrast to Nafion (registered trademark) 117, which is a commercially available polymer electrolyte membrane often used as a polymer electrolyte membrane of DMFC, the polymer electrolyte membrane of the present invention has a significantly low methanol permeability coefficient and high output. Since a voltage can be obtained, it is clear that the polymer electrolyte membrane is excellent.

  The polymer electrolyte membranes of the present invention in Examples 6 to 9 are particularly suitable for fuel cells using hydrogen as fuel. Although the polymer electrolyte membranes of the present invention in Examples 6 to 9 have the same initial characteristics as those of the polymer electrolyte membranes of Comparative Examples 6 to 9 that do not contain the compound having the structure represented by Chemical Formula 2, the durability is durable. It can be seen that the characteristics are greatly improved. Further, in contrast to Nafion (registered trademark) 112, which is a commercially available polymer electrolyte membrane often used in a fuel cell using hydrogen as a fuel, the polymer electrolyte membrane of the present invention has an initial characteristic equal to or higher than that. It can be seen that the polymer electrolyte membrane has excellent characteristics. Although the durability time of the polymer electrolyte membrane of the present invention is slightly inferior to that of Nafion (registered trademark) 112, the electrolyte membrane does not contain fluorine, and therefore discharges harmful substances such as hydrofluoric acid during the operation of the fuel cell. It has the advantage that it can be suppressed and has few problems in disposal.

From these facts, the polymer electrolyte membrane of the present invention can greatly improve its characteristics by using it as a polymer electrolyte membrane of a fuel cell using hydrogen or methanol as fuel, and contribute greatly to the industry. is there.

Claims (24)

At least (A) the following chemical formula 1 in the molecule;

[In the chemical formula 1, X is a —S (═O) ₂ — group or —C (═O) — group, Y is H or a monovalent cation, Z ¹ is either an O or S atom, Z ² represents an O atom, an S atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group or a cyclohexyl group, and n1 represents an integer of 0 or more. To express. ]
A polymer composition comprising a sulfonic acid group-containing polymer having a structure represented by: (B) and a compound represented by the following chemical formula 2:

[In Chemical Formula 2, R represents a divalent organic group. ] The polymer composition according to claim 1, wherein the sulfonic acid group-containing polymer further contains a structure represented by Chemical Formula 3.

[In Chemical Formula 3, Ar ¹ is a divalent aromatic group, Z ³ is either an O or S atom, Z ⁴ is an O atom, an S atom, a —C (CH ₃ ) ₂ — group, —C Any one of (CF ₃ ) ₂ — group, —CH ₂ — group and cyclohexyl group, n2 represents an integer of 0 or more. ] The polymer composition according to claim 2, wherein Ar ^{1 of the} sulfonic acid group-containing polymer is one or more groups selected from structures represented by the following chemical formulas 4 to 7.

The polymer composition according to claim 3, wherein Ar ^{1 of the} sulfonic acid group-containing polymer has a structure represented by Chemical Formula 7.   The polymer composition according to claim 1, wherein the sulfonic acid group-containing polymer has a sulfonic acid group content of 0.3 to 5.0 meq / g. ^2. The polymer composition according to claim 1, wherein Z ¹ and Z ² of the sulfonic acid group-containing polymer are both O atoms, and n1 is 3 or more. ^3. The polymer composition according to claim 2, wherein Z ³ and Z ⁴ of the sulfonic acid group-containing polymer are both O atoms and n2 is 3 or more. The polymer composition according to claim 1, wherein the sulfonic acid group-containing polymer further has a structure represented by the following chemical formula 8.

[In Chemical Formula 8, X represents a —S (═O) ₂ — group or —C (═O) — group, Y represents H or a monovalent cation, and Z ⁵ represents either an O or S atom. . ]   The polymer composition according to claim 8, wherein the sulfonic acid group-containing polymer further contains a structure represented by Chemical Formula 3. The polymer composition according to claim 9, wherein the sulfonic acid group-containing polymer further has a structure represented by Chemical Formula 9.

[In Chemical Formula 9, Ar ² represents a divalent aromatic group, and Z ⁶ represents either an O or S atom. ] The polymer composition according to claim 10, wherein Ar ^{2 of the} sulfonic acid group-containing polymer is one or more groups selected from structures represented by Chemical Formulas 4 to 7. The polymer composition according to claim 11, wherein Ar ^{2 of the} sulfonic acid group-containing polymer has a structure represented by Chemical Formula 7. The polymer composition according to claim 8, wherein Z ¹ and Z ² of the sulfonic acid group-containing polymer are O or S atoms, and n1 is 1. The polymer composition according to claim 9, wherein Z ³ and Z ⁴ of the sulfonic acid group-containing polymer are O or S atoms, and n2 is 1. The sulfonic acid group-containing polymer has at least repeating units represented by chemical formulas 1, 3, 8, and 9, respectively, and mol% of each repeating unit and mol% of other repeating structures satisfy Formulas 1 to 3. The polymer composition according to claim 1.

(In the above formula, n3 is the mol% of the structure represented by Chemical Formula 8, n4 is the mol% of the structure represented by Chemical Formula 1, n5 is the mol% of the structure represented by Chemical Formula 9, and n6 is the chemical formula. 3 represents the mol% of the structure represented by 3, and n7 represents the mol% of the other repeating structure.) 2. The polymer composition according to claim 1, wherein R of the compound represented by Chemical Formula 2 is one or more groups selected from the group consisting of structures represented by Chemical Formulas 10 to 12 below.

  The polymer composition according to claim 1, wherein R in the compound represented by Formula 2 is Formula 10.   2. The polymer composition according to claim 1, wherein the content of the compound having a structure represented by Chemical Formula 2 is 1 to 30% by weight.   A polymer composition obtained from the polymer composition according to claim 1, wherein at least a part of the allyl group of the compound having the structure represented by Chemical Formula 2 is an allyl group and / or sulfonic acid group-containing polymer of the compound. A polymer composition characterized by having a bond reacted with.   A polymer electrolyte membrane comprising the polymer composition according to claim 1.   A polymer electrolyte membrane / electrode assembly comprising the polymer composition according to any one of claims 1 to 19 in a polymer electrolyte and / or an electrode catalyst layer.   A fuel cell using the polymer electrolyte membrane / electrode assembly according to claim 21.   A method for producing a polymer electrolyte membrane, comprising a step of heating a membrane formed from the polymer composition according to any one of claims 1 to 18 at a temperature of 200 to 300 ° C. The sulfonic acid group of the sulfonic acid group-containing polymer is a metal salt before heating, and has a step of converting the sulfonic acid group into an acid form by treatment with an acid after the heating. The manufacturing method of the polymer electrolyte membrane of description.