JP4576620B2 - Method for producing nanostructure control polymer ion exchange membrane - Google Patents

Description

The present invention relates to a method for producing a polymer ion exchange membrane which is a solid polymer electrolyte membrane suitable for use in a fuel cell.
The present invention also relates to a method for producing a polymer ion exchange membrane that is a solid polymer electrolyte membrane suitable for a fuel cell and that can control ion exchange capacity within a wide range together with excellent oxidation resistance, heat resistance and dimensional stability. .

  A fuel cell using a solid polymer electrolyte type ion exchange membrane is expected to be used as a power source for electric vehicles and a simple auxiliary power source because of its high energy density. In this fuel cell, the development of a polymer ion exchange membrane having excellent characteristics is one of the most important technologies.

  In a polymer ion exchange membrane fuel cell, the ion exchange membrane acts as an electrolyte for conducting protons, and also prevents direct mixing of hydrogen or methanol as a fuel with air (oxygen) as an oxidant. It also has a role as a diaphragm. As such an ion exchange membrane, the ion exchange capacity is large as an electrolyte, and since a current is passed for a long period of time, the membrane is chemically stable, particularly resistant to hydroxyl radicals and the like which are the main cause of membrane degradation (oxidation resistance). It is required that the film has excellent heat resistance at 80 ° C. or higher, which is the operating temperature of the battery, and that the water retention of the film is constant and high in order to keep the electric resistance low. On the other hand, the role as a diaphragm requires that the film has excellent mechanical strength and dimensional stability and that it does not have excessive permeability to hydrogen gas, methanol, oxygen gas or air.

  Early polymer ion exchange membrane fuel cells used hydrocarbon polymer ion exchange membranes produced by copolymerization of styrene and divinylbenzene. However, since this ion exchange membrane has very poor durability due to oxidation resistance, its practicality is poor. Thereafter, a perfluorosulfonic acid membrane “Nafion (registered trademark of DuPont)” developed by DuPont, etc. Has been used in general.

  However, conventional fluorine-containing polymer ion exchange membranes such as “Nafion (registered trademark)” are excellent in chemical durability and stability, but have a small ion exchange capacity of around 1 meq / g, Insufficient water retention causes drying of the ion exchange membrane, resulting in a decrease in proton conductivity, and when methanol is used as a fuel, membrane swelling or methanol or hydrogen gas crossover occurs.

  In order to increase the ion exchange capacity, if a large number of sulfonic acid groups are introduced, the polymer chain does not have a cross-linked structure, so the membrane swells and the size of the membrane changes or the strength decreases significantly. And can easily be damaged. Therefore, in conventional ion exchange membranes of fluorine-containing polymers, it is necessary to suppress the amount of sulfonic acid groups to such an extent that the size and strength of the membrane can be maintained, so that the ion exchange capacity can only be about 1 meq / g. There wasn't.

  In addition, fluorine-containing polymer ion exchange membranes such as Nafion (registered trademark) are difficult and complicated to synthesize monomers, and the process of polymerizing them to produce polymer membranes is also complicated. It becomes expensive and becomes a major obstacle when a proton exchange membrane fuel cell is mounted on an automobile and put to practical use. Therefore, efforts have been made to develop a low-cost and high-performance electrolyte membrane that replaces the Nafion (registered trademark) and the like.

  On the other hand, in the radiation graft polymerization method closely related to the present invention, an attempt has been made to produce a solid polymer electrolyte membrane by grafting a monomer capable of introducing a sulfonic acid group to the polymer membrane. The present inventors have repeatedly studied to develop these new solid polymer electrolyte membranes. By introducing a styrene monomer into a polytetrafluoroethylene film having a crosslinked structure by a radiation graft reaction and then sulfonating, high ions can be obtained. An application was filed for a solid polymer electrolyte membrane characterized by exchange capacity and a method for producing the same (Patent Document 1). However, in this ion exchange membrane, since the styrene graft chain is composed of hydrocarbons, when a current is passed through the membrane for a long time, oxidation occurs in a part of the graft chain portion, and the ion exchange ability of the membrane is lowered.

  Furthermore, the present inventors introduced a sulfonic group into the graft chain following the radiation grafting of the fluorine-based monomer or the radiation co-grafting of the fluorine-based monomer to the polytetrafluoroethylene film having a crosslinked structure. An application for a solid polymer electrolyte membrane having an exchange capacity and excellent oxidation resistance and a method for producing the same were filed (Patent Document 2). However, in a normal fluoropolymer film, the grafting reaction of fluorinated monomers hardly proceeds to the inside of the film, and depending on the reaction conditions, the grafting reaction is limited to the film surface, so it is difficult to improve the characteristics as an electrolyte membrane. It has been found.

JP 2001-348439 A JP 2002-348389 A

  The present invention has been made in order to overcome the above-described problems of the prior art, and in polymer solid electrolytes, the ion exchange capacity is small, and the dimensional stability of the membrane is a drawback of the polymer ion exchange membrane. The problems to be solved are to have poor properties, low oxidation resistance, low heat resistance, and prevention of crossover of methanol or hydrogen gas as fuel.

  The present invention provides a polymer ion exchange membrane having a high ion exchange capacity and excellent oxidation resistance and dimensional stability and a method for producing the same, and in particular, an ion exchange membrane suitable for use in a fuel cell. And a method for manufacturing the same.

  As a result of research on the introduction of sulfonic acid groups into the resulting graft chain by irradiating the polymer film with radiation and grafting or co-grafting various monomers, this polymer film was used as a substrate. The substrate is irradiated with hydrogen ions, helium ions, or high-energy heavy ions to form a large number of nano-sized irradiation damaged regions, and specific functional monomers are graft polymerized into the damaged regions. The present inventors have invented a method for producing a polymer ion exchange membrane having a sulfonic acid group as a halogen group or an ester group. The polymer ion exchange membrane of the present invention is characterized in that the graft ratio of the monomer to the polymer film substrate is 10 to 120% and the ion exchange capacity is 0.3 to 2.5 meq / g. In addition, the polymer ion exchange membrane of the present invention is capable of appropriately controlling characteristics such as ion exchange capacity within a wide range, has high oxidation resistance and heat resistance, and has high dimensional stability of the membrane. It has excellent characteristics.

The polymer ion exchange membrane produced by the present invention has a wide range of ion exchange capacities along with excellent oxidation resistance, dimensional stability, electrical conductivity, and methanol resistance.
Because of these characteristics, the ion exchange membrane of the present invention is particularly suitable for a fuel cell membrane. Moreover, it is useful as an inexpensive and durable electrolytic membrane or ion exchange membrane.

In one embodiment of the present invention, a polyethylene terephthalate film substrate is used as the polymer film substrate.
This film is irradiated with hydrogen ions, helium ions or high-energy heavy ions by a cyclotron accelerator or the like. Here, heavy ions refer to ions that are higher than carbon ions. Irradiation of these ions causes irradiation damage to the polymer film due to ion irradiation, and the irradiation damage area depends on the mass and energy of the ions to be irradiated, but spreads from about nano size to several hundred nano size per ion. (H. Kudo and Y. Morita, J. Polym. Sci., Part B, Vol. 39, pp. 757-762 (2001)).

The number of ions to be irradiated is preferably 10 ⁴ to 10 ¹⁴ ions / cm ² so that irradiation damaged areas by individual ions do not overlap. Irradiation is performed with high-energy ions in a state where, for example, a 10 cm × 10 cm film substrate is fixed to an irradiation stand in an irradiation chamber connected to a cyclone accelerator or the like, and a vacuum of 10 ⁻⁶ Torr or less is drawn in the irradiation chamber. It is better to do this while scanning. The irradiation amount can be determined from the amount of ion current measured in advance with a high-precision ammeter and the irradiation time. As a kind of high energy heavy ions to be irradiated, ions having a mass greater than or equal to carbon ions, which can be actually accelerated by an accelerator, are preferable.

  Ion species such as carbon, nitrogen, oxygen, neon, argon, krypton, and xenon are more preferable from the viewpoint of easy generation of ions and easy handling of ions. Moreover, in order to enlarge the irradiation damage area | region of one ion, you may use large mass ions, such as a gold ion, a bismuth ion, or a uranium ion. Although the energy of ions depends on the ion species, it is sufficient if the energy is sufficient to penetrate the polymer film substrate in the thickness direction. For example, in a polyethylene terephthalate film substrate having a thickness of 50 μm, carbon ions are 40 MeV. As described above, neon ions are 80 MeV or more, and argon ions are 180 MeV or more. Similarly, at a thickness of 100 μm, carbon ions are 62 MeV or more, neon ions are 130 MeV or more, and argon ions are 300 MeV or more. Further, a film substrate having a thickness of 40 μm can be penetrated with xenon ion 450 MeV, and a film substrate having a thickness of 20 μm with uranium ion 2.6 GeV.

  Even if the ion used for irradiation is about 1/2 the film thickness of the film substrate, the same or different ions are irradiated from both sides of the film while changing the irradiation amount. By irradiating from both sides of the film with a combination of heavier ions having a shorter range, it is possible to create different distributions of irradiation damage areas from the surface of the film toward the inside. This results in different amounts or lengths of graft chains in the film and also different forms of polymer structure in the grafting reaction described below. As a result, the distribution of moisture in the film substrate and the permeation of fuel gas in the film can be controlled using the change in the distribution of sulfonic acid groups in the graft chain of the film substrate.

  Moreover, in order to penetrate the film thickness of a heavy ion, the ion of very high energy as mentioned above is required. For example, the range of 22 MeV carbon ions in a polyethylene terephthalate film substrate is about 25 μm, and the film substrate having a thickness of 50 μm cannot be penetrated. Energy of about 40 MeV is required to penetrate the 50 μm polyethylene terephthalate film substrate, but 22 MeV carbon ions are sufficient when irradiated from both sides of the film. Generating higher energy ions requires a larger accelerator and is expensive to install. Also from this fact, ion irradiation from both sides is extremely effective for the production of the ion exchange membrane in the present invention.

In order to obtain a membrane having a large ion exchange capacity, the ion irradiation amount may be increased. When the ion irradiation amount is large, the film base material is deteriorated, or the irradiation damage regions are overlapped, and the graft efficiency of the monomer described later is deteriorated. Further, when the irradiation amount is small, the amount of monomer grafting is small and a sufficient ion exchange capacity cannot be obtained. Therefore, the ion irradiation amount is preferably in the range of 10 ⁴ pieces / cm ² to 10 ¹⁴ pieces / cm ² .

The polymer ion exchange membrane according to the present invention is prepared by adding the following monomers to the ion-irradiated polyethylene terephthalate film base material, freeze-degassing, heating, and graft-polymerizing the monomer onto the film base material. Produced by converting a sulfonyl halide group [—SO ₂ X ¹ ], a sulfonate group [—SO ₃ R ¹ ], or a halogen group [—X ² ] in a molecular chain to a sulfonate group [—SO ₃ H]. To do. Further, phenyl groups, ketones, ether groups, etc. present in the hydrocarbon monomer units in the graft chain can be produced by introducing sulfonic acid groups with chlorosulfonic acid. In the present invention, the monomer or the monomer / comonomer system shown in the following (1) to (10) may be used as a monomer (hereinafter also referred to as “graft monomer” or simply “monomer”) to be graft-polymerized on the film substrate. (Hereinafter, the monomer means that a sulfonic acid group can be introduced into this monomer unit after grafting, and the conomer means that the sulfonic acid group cannot be easily introduced into this comonomer unit after grafting) .

(1) Group A: a monomer having a sulfonyl halide group, CF ₂ = CF (SO ₂ X ¹ ) (wherein X ¹ is a halogen group, -F or -Cl; the same shall apply hereinafter), CH _{2 ^{= CF (SO 2 X 1)}} , and _{CF 2 = CF (OCH 2 (} CF 2) 1 ~ 4 SO 2 X 1) 1 or more kinds of monomers selected from the consisting of group.

(2) Group B: CF ₂ = CF (SO ₃ R ¹ ), which is a monomer having a sulfonate group (wherein R ¹ is an alkyl group, —CH ₃ , —C ₂ H ₅ or —C (CH ₃ ) _{3. The} same shall apply hereinafter.) ¹ ) selected from the group consisting of CH ₂ ═CF (SO ₃ R ¹ ) and CF ₂ ═CF (OCH ₂ (CF ₂ ) ₁ to ₄ SO ₃ R ¹ ). One type or two or more types of monomers.

(3) C _{group: CF 2 = CF (O (} CH 2) 1 ~ 4 X 2) (.. Wherein, X ² is -Br or -Cl halogen group hereinafter), and CF ₂ = CF One or two types of monomers selected from the group consisting of (OCH ₂ (CF ₂ ) ₁ to ₄ X ² ).

(4) The following groups A to C:
Group _{A: CF 2 = CF (SO 2} X 1) (.. Wherein, X ¹ is is -F or -Cl halogen group hereinafter the _{same), CH 2 = CF (SO} 2 X 1), and CF _{2 = CF (OCH 2 (CF 2} ) 1 ~ 4 SO 2 X 1);
Group B: CF ₂ = CF (SO ₃ R ¹ ) (wherein R ¹ is an alkyl group and is —CH ₃ , —C ₂ H ₅ , or —C (CH ₃ ) _{3. The} same shall apply hereinafter), CH. ^{_{2 = CF (SO 3 R 1}} ), and _{CF 2 = CF (OCH 2 (} CF 2) 1 ~ 4 SO 3 R 1);
Group _{C: CF 2 = CF (O (} CH 2) 1 ~ 4 X 2) (.. Wherein, X ² is -Br or -Cl halogen group hereinafter), and CF ₂ = CF (OCH ₂ (CF ₂ ) ₁ to ₄ X ² )
2 or more types of monomers selected from at least 2 or more different groups.

(5) A _{Group: CF 2 = CF (SO 2} X 1) (.. Wherein, X ¹ is is -F or -Cl halogen group hereinafter the _{same), CH 2 = CF (SO} 2 X 1), And CF ₂ = CF (OCH ₂ (CF ₂ ) ₁ to ₄ SO ₂ X ¹ ), one or more monomers selected from the group consisting of CF ₂ = CR ² (COOR ³ (Wherein R ² is —CH ₃ or —F, R ³ is —H, —CH ₃ , —C ₂ H ₅ or —C (CH ₃ ) ₃ , and so on), and CH ₂ = Monomer / comonomer system in which one or more comonomers selected from the group consisting of CR ² (COOR ³ ) are added in an amount of 50 mol% or less based on the total monomers.

(6) Group B: CF ₂ = CF (SO ₃ R ¹ ) (wherein R ¹ is an alkyl group, —CH ₃ , —C ₂ H ₅ , or —C (CH ₃ ) ₃ . ), CH ₂ ═CF (SO ₃ R ¹ ), and CF ₂ ═CF (OCH ₂ (CF ₂ ) ₁ to ₄ SO ₃ R ¹ ), one or more monomers selected from the group consisting of An acrylic monomer, CF ₂ ═CR ² (COOR ³ ) (wherein R ² is —CH ₃ or —F, and R ³ is —H, —CH ₃ , —C ₂ H ₅ or —C (CH _{3) 3.} hereinafter the same.), and CH ^₂ = CR ₂ (one or more comonomers selected from the group consisting of COOR ^3), of 50 mol% or less based on total monomers amount added monomer / comonomer system.

(7) C _{group: CF 2 = CF (O (} CH 2) 1 ~ 4 X 2) (.. Wherein, X ² is -Br or -Cl halogen group hereinafter), and CF ₂ = CF One or two or more types of monomers selected from the group consisting of (OCH ₂ (CF ₂ ) ₁ to ₄ X ² ) may be an acrylic monomer, CF ₂ = CR ² (COOR ³ ) (wherein R ² Is —CH ₃ or —F, R ³ is —H, —CH ₃ , —C ₂ H ₅ or —C (CH ₃ ) ₃ , and so on.), And CH ₂ = CR ² (COOR ³ A monomer / comonomer system in which one or more kinds of comonomers selected from the group consisting of) are added in an amount of 50 mol% or less based on the total monomers.

  (8) Group D: One or more monomers selected from the group consisting of styrene, styrene derivative monomers 2,4-dimethylstyrene, vinyltoluene, and 4-tert-butylstyrene.

(9) Group E: acenaphthylene, vinyl ketone CH ₂ ═CH (COR ⁴ ) (wherein R ⁴ is —CH ₃ , —C ₂ H ₅ or a phenyl group (—C ₆ H ₅ )), and vinyl ether. CH ₂ ═CH (OR ⁵ ) (wherein R ⁵ is —C _n H _{2n + 1} (n = 1 to 5), —CH (CH ₃ ) ₂ , —C (CH ₃ ) ₃ , or phenyl group) One or more monomers selected from the group consisting of:

(10) The following D to F groups:
Group D: styrene, styrene derivative monomers 2,4-dimethylstyrene, vinyltoluene, and 4-tert-butylstyrene; and Group E: acenaphthylene, vinylketone CH ₂ ═CH (COR ⁴ ) (wherein R ⁴ is —CH ₃ , —C ₂ H ₅ or a phenyl group (—C ₆ H ₅ )), and vinyl ether CH ₂ ═CH (OR ⁵ ) (wherein R ⁵ is —C _n H _{2n + 1} (n = 1~5), - CH (CH 3) 2, -C (CH 3) 3, or a phenyl group).
Group F: CF ₂ = CR ² (COOR ³ ) (wherein R ² is —CH ₃ or —F, and R ³ is —H, —CH ₃ , —C ₂ H ₅ or —C (CH ₃ )). _{3. The} same applies hereinafter.), And CH ₂ = CR ² (COOR ³ )
Two or more monomer / comonomer systems selected from at least two or more different groups.

Here, the acrylic monomer in the above (5) to (7), and (10), for _{example, CH 2 = C (CH 3} ) (COOH), CH 2 = CF (COOCH 3), CH 2 = CF (COOC (CH ₃ ) ₃ ), CF ₂ ═CF (COOCH ₃ ), or CF ₂ ═C (CH ₃ ) (COOCH ₃ ). Since these comonomers cannot introduce a sulfonic acid group into these comonomer units after grafting, it is preferable that the monomer / comonomer system be limited to 50 mol% or less based on the total monomers.

The monomers (1) to (10) and the monomer / comonomer are Freon 112 (CCl ₂ FCCl ₂ F), Freon 113 (CCl ₂ FCClF ₂ ), dichloroethane, chloromethane, n-hexane, alcohol, t-butanol, You may use what was diluted with solvents, such as benzene, toluene, cyclohexane, cyclohexanone, and dimethylsulfoxide.

  The monomer is selected from the group consisting of divinylbenzene, triallyl cyanurate, triallyl isocyanurate, 3,5-bis (trifluorovinyl) phenol, and 3,5-bis (trifluorovinyloxy) phenol. One or more kinds of crosslinking agents may be added and graft-polymerized in an amount of 30 mol% or less based on the total monomers.

  Graft polymerization is a graft polymerization reaction in which a film base irradiated with ions is placed in a pressure vessel made of stainless steel or glass and sufficiently evacuated, and a monomer excluding oxygen gas is added in advance by bubbling of inert gas or freeze degassing. Let The graft polymerization temperature can be from room temperature to the boiling point of the monomer or solvent, and is usually 0 ° C to 100 ° C. Since the presence of oxygen hinders the grafting reaction, these series of operations are performed in an inert gas such as argon gas or nitrogen gas, and the monomer or a solution in which the monomer is dissolved in a solvent is treated in a conventional manner (bubbling or freezing). Use with oxygen removed by degassing. The graft ratio (see the formula (1) in the example) becomes higher as the ion irradiation dose and the grafting time are longer.

  Examples of the film substrate that can be used in the present invention include hydrocarbon polymer films having good monomer solution permeability. In addition, although the fluorine-based polymer film does not have good penetrability of the monomer solution, the monomer penetrates into the film by irradiating ions, and the graft reaction proceeds inside. As a film substrate that can be used in the present invention, instead of a polyethylene terephthalate film substrate, ultrahigh molecular weight polyethylene, polypropylene, polystyrene, polyamide, aromatic polyamide, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyether ketone, polyether Ether ketone, polyethersulfone, polyphenylene sulfide, or polysulfone film substrates may be used.

  Instead of the polyethylene terephthalate film substrate, a polyimide-based polymer film such as polyimide, polyether imide, polyamide imide, polybenzimidazole, or polyether ether imide film substrate may be used.

  Furthermore, instead of the polyethylene terephthalate film substrate, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, or tetrafluoroethylene-perfluoroalkyl vinyl ether A copolymer film substrate may be used.

  When the fluorine-based film is crosslinked, a crosslinked structure is formed in the polymer structure, the graft ratio of the monomer is improved, and the heat resistance is further increased, so that a decrease in film strength due to irradiation can be suppressed. Therefore, it is preferable to use a crosslinked film in order to produce a fuel cell that exhibits high performance in high temperature applications. For example, when styrene is used as the graft monomer, the graft ratio can be significantly increased with crosslinked polytetrafluoroethylene compared to uncrosslinked polytetrafluoroethylene, which is 2 to 10 times that of uncrosslinked polytetrafluoroethylene. The present inventors have already found that a sulfonic acid group can be introduced into a crosslinked polytetrafluoroethylene (see Patent Document 1; JP-A-2001-348439). A method for producing a tetrafluoroethylene-hexafluoropropylene copolymer or a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer having a crosslinked structure is described in Radiation Physical Chemistry vol. 42, NO. 1/3, pp. 139-142, Published in 1993.

  Therefore, in the present invention, instead of the polyethylene terephthalate film substrate, ultrahigh molecular weight polyethylene having a crosslinked structure, polypropylene, polystyrene, polyamide, aromatic polyamide, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyether ketone It is also preferred to use polyetheretherketone, polyethersulfone, polyphenylene sulfide, or polysulfone film substrates.

A polyimide, polyetherimide, polyamideimide, polybenzimidazole, or polyetheretherimide film substrate having a crosslinked structure is also suitable.
Similarly, polyvinylidene fluoride having a crosslinked structure, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer film Substrates are also suitable.

In order to introduce a sulfonic acid group into the grafted film substrate, the [—SO ₂ X ¹ ] group in the grafted molecular chain of the above (1), (4) and (5) is replaced with a high concentration of caustic potash (KOH). ) Or an aqueous solution of caustic soda (NaOH), a water / alcohol solution or a water / dimethylsulfoxide solution, at a temperature of room temperature to 100 ° C., and sulfonate [—SO ₃ M] (wherein M is an alkali metal) Na or K.), and then the sulfonate group is converted to a sulfonate group [—SO ₃ H] at 60 ° C. in a 1N to 2N sulfuric acid solution. The alcohol used in the water / alcohol solution is an alcohol having 1 to 3 carbon atoms. The mixing ratio of the water / alcohol solution or the water / dimethyl sulfoxide solution is not particularly limited.

In addition, the [—SO ₃ R ¹ ] group in the grafted molecular chain of (2), (4) and (6) above is either acidic in about 1N potassium hydroxide solution or about 1N sulfuric acid solution. The solution is reacted at a temperature of room temperature to 100 ° C. to hydrolyze to form a sulfonic acid group [—SO ₃ H]. Similarly, the halogen group [—X ² ] in the grafted molecular chain of (3), (4) and (7) above is an aqueous solution of sulfite or bisulfite, or water of sulfite or bisulfite. / Alcohol mixed solution to give a sulfonate group [—SO ₃ M] (wherein M is an alkali metal and Na or K), and then the sulfonate group is converted to a sulfonate group [—SO ₃ H]. And

  Furthermore, the grafted molecular chain of (8) to (10) above, the phenyl group, naphthalene group, ketone and ether group in the molecular chain are in a dichloroethane solution or chloroform solution of chlorosulfonic acid at a temperature of room temperature to 60 ° C. The sulfonic acid group can be introduced by reaction. In the case of the ketone and ether groups, a sulfonic acid group is introduced into the graft chain by dehydrochlorination reaction with respect to these groups and surrounding structures. In the case of a hydrocarbon-based film base material having an aromatic ring, introduction of a sulfone group by chlorosulfonic acid causes the base material itself to be sulfonated. In this case, a film base material having a crosslinked structure is particularly effective.

In addition, when the vinyl ketone CH ₂ ═CH (COR ⁴ ) or the vinyl ether CH ₂ ═CH (OR ⁵ ) having an alkyl group and a phenyl group in the above (9) and (10) is used as a graft monomer, an alkyl group The distribution of sulfonic acid groups in the graft chain can be controlled by utilizing the difference in sulfonation rate of these groups by changing the abundance ratio of the phenyl group in the graft chain. Even so, oxidation resistance can be imparted.

  Furthermore, the ester group in the graft chain obtained by the above (5) to (7) also becomes a carboxyl group by reaction with a solution of caustic soda (NaOH) or caustic potash (KOH). The carboxyl group is extremely useful for retaining moisture, which is important for ion conduction in the film when the graft film is used as an ion exchange membrane.

  The polymer ion exchange membrane according to the present invention can change the ion exchange capacity of the membrane according to the graft amount, that is, the amount of sulfonic acid groups introduced. The graft ratio (see the formula (1) in the example) is higher as the dose of ions in the same monomer is higher, and is higher as heavy ions, and the contact time (grafting time) between the film substrate and the monomer is longer, or The higher the grafting reaction temperature, the higher. However, the graft ratio tends to be gradually saturated at 60 to 80%. In the present invention, the graft ratio is 10 to 120%, preferably 15 to 100%, relative to the film substrate.

  Here, the ion exchange capacity is the amount of ion exchange groups (meq / g) per gram weight of the dry ion exchange membrane. Depending on the type of graft monomer, when the graft rate is 10% or less, the ion exchange capacity is about 0.3 meq / g or less, and when the graft rate is 120% or more, the swelling of the membrane increases. That is, if a large amount of ion exchange groups are introduced to increase the graft ratio, the ion exchange capacity increases. However, if the amount of ion-exchange groups is excessively large, the membrane swells when it contains water and the strength of the membrane decreases. Therefore, in the polymer ion exchange membrane of the present invention, the ion exchange capacity is 0.3 meq / g to 2.5 meq / g, preferably 0.5 meq / g to 2.0 meq / g.

Apart from the case of using the above grafting reaction, a polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ultrahigh molecular weight polyethylene, polypropylene, polystyrene, or polyamide that does not have a crosslinked structure or has a crosslinked structure. A molecular film substrate is irradiated with 10 ⁴ to 10 ¹⁴ ions / cm ^{2 of} high energy heavy ions, or 10 ⁴ to 10 of high energy heavy ions having a range less than the film thickness on one surface of the film substrate. ^After irradiating ¹⁴ ions / cm ^{2 and} irradiating the same kind or different kind of ions having a range below the film thickness with different doses within the above range so that the range in the film overlaps with the other surface The polymer substrate is reacted with chlorosulfonic acid to introduce a sulfonic acid group [—SO ₃ H] directly into the molecular chain of the film substrate to form a polymer ion exchange membrane. It may be manufactured. In this method, ions having a mass greater than that of carbon ions are particularly effective. This is because in the above polymer film substrate, there are —CH ₂ —CH ₂ — units or CH ₂ —CF ₂ — units in the molecule, and many double bonds are present in the irradiation damaged region in the film by heavy ion irradiation. This is because a hydrogen atom attached to the tertiary carbon is generated, and this reacts with chlorosulfonic acid to fix a high concentration of sulfonic acid groups, thereby obtaining a polymer ion exchange membrane exhibiting ion exchange ability.

  Instead of ion irradiation, after ion irradiation, irradiation with ionizing radiation of X-rays, γ-rays, and electron beams is further performed to graft polymerize monomers or react with chlorosulfonic acid to polymer ion exchange membranes. May be manufactured.

  In fuel cell membranes, methanol is currently considered as one of the fuel candidates, but the Nafion (registered trademark) membrane, which is a perfluorosulfonic acid membrane of the prior art, has no cross-linking structure between molecules. The fuel swells greatly, causing a fuel crossover in which methanol, which is a fuel, diffuses from the anode (fuel electrode) to the cathode (air electrode) through the cell membrane, resulting in a problem of reducing power generation efficiency.

When the moisture content of the ion exchange membrane for a fuel cell is too low, the electric conductivity and gas permeability coefficient change due to slight changes in operating conditions, which is not preferable. Since most of the conventional Nafion (registered trademark) film is composed of -CF _2- , when the battery is operated at a high temperature of 80 ° C or higher, water atoms in the film are insufficient, and the conductivity of the film rapidly increases. descend. In addition, since the entire membrane is swollen by methanol fuel, crossover of methanol and fuel gas occurs remarkably. In contrast, in the ion exchange membrane of the present invention, in the polymer ion exchange membrane of the present invention, the water content of the exchange membrane can be controlled by the amount of sulfonic acid group introduced and the molecular structure of the graft monomer. In addition, since the sulfonic acid group exists only in the linear irradiation damage region which is the trajectory of ions, the overall swelling of the membrane and the crossover of the fuel can be reduced.

  Ion irradiation is not affected by the molecular structure or crystal structure of the polymer film as a substrate, and can be applied to many polymer films. Therefore, in the polymer ion exchange membrane according to the present invention, if the film substrate does not permeate methanol, the movement of hydrogen ions occurs only through the sulfonated graft chain in the ion irradiation damaged region. Almost no swelling of the membrane by alcohols was observed. Therefore, the polymer ion exchange membrane of the present invention is useful as a membrane for a direct methanol fuel cell using methanol as a direct fuel without using a reformer.

  The polymer ion exchange membrane of the present invention can introduce a hydrophilic group such as a carboxyl group or a hydrocarbon structure into the graft chain in addition to the sulfonic acid group. The water content mainly depends on the amount of the sulfonic acid group, but can be controlled in the range of 10 to 120% by weight. In general, the water content increases as the ion exchange capacity increases. However, since the water content of the ion exchange membrane of the present invention can be controlled, the water content of the membrane is 10 to 120% by weight, preferably 20 to 100% by weight. %.

  In addition, the polymer ion membrane of the present invention can be put to practical use because the mechanical properties and dimensional stability of the membrane are maintained even when a large amount of sulfonic acid group having an ion exchange capacity of 2.5 meq / g is introduced. Can do. A membrane having a high ion exchange capacity and excellent mechanical properties is extremely useful in practice.

The higher the electric conductivity related to the ion exchange capacity of the polymer ion exchange membrane, the smaller the electric resistance and the better the performance as an electrolyte membrane. However, when the electric conductivity of the ion exchange membrane at 25 ° C. is 0.05 (Ω · cm) ⁻¹ or less, the output performance as a fuel cell often deteriorates remarkably. In many cases, the degree is designed to be 0.05 (Ω · cm) ⁻¹ or more, and 0.10 (Ω · cm) ⁻¹ or more for higher performance ion exchange membranes. In the ion exchange membrane according to the present invention, the electric conductivity of the ion exchange membrane at 25 ° C. was equal to or higher than that of the Nafion (registered trademark) membrane.

  In order to increase the electric conductivity of the ion exchange membrane, it is conceivable to reduce the thickness of the ion exchange membrane. However, at present, an excessively thin ion exchange membrane is easily damaged, and it is difficult to manufacture the ion exchange membrane itself. Therefore, an ion exchange membrane having a thickness of 30 to 200 μm is usually used. In the present invention, a film thickness of 10 to 300 μm, preferably 20 to 150 μm is effective.

  In a fuel cell membrane, the oxidation resistance of the membrane is a very important characteristic related to the durability (life) of the membrane. This is because OH radicals and the like generated during battery operation attack the ion exchange membrane and deteriorate the membrane. A polymer ion exchange membrane obtained by grafting hydrocarbon-based styrene to a polymer film and then sulfonating polystyrene graft chains has extremely low oxidation resistance. For example, a polystyrene graft-crosslinked fluororesin ion exchange membrane sulfonated with a polystyrene chain having a graft ratio of 93% deteriorates in about 60 minutes in an aqueous 3% hydrogen peroxide solution at 80 ° C. It becomes almost half (Comparative Example 3). This is because the polystyrene chain is easily decomposed by the attack of OH radicals.

  In contrast, the polymer ion exchange membrane according to the present invention is a polymer having a fluorine-based monomer as a graft chain or a highly cross-linked product of a hydrocarbon-based monomer, and the graft body has a nano-order extremely fine irradiation damage region. Therefore, the oxidation resistance is extremely high, and the ion exchange capacity hardly changes even when placed in a 3% hydrogen peroxide aqueous solution at 80 ° C. for 24 hours or more.

  As described above, the polymer ion exchange membrane of the present invention has excellent dimensional stability, oxidation resistance, and methanol resistance, and has an ion exchange capacity of 0.3-2. It can be controlled in a wide range of 5 meq / g.

Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this.
Each measured value was determined by the following measurement.

(1) Graft ratio When the film base is a main chain part, and a graft polymerized part of a fluorine monomer or a hydrocarbon monomer and the like is a graft chain part, the weight ratio of the graft chain part to the main chain part is as follows: The graft ratio (X _dg (% by weight)).

(2) Ion Exchange Capacity The ion exchange capacity (I _ex (meq / g)) of the membrane is expressed by the following equation.

For the measurement of n (acid group) _obs , the membrane was again immersed in a 1 M (1 mol) sulfuric acid solution at 50 ° C. for 4 hours for complete accuracy, so that the acid form (H form) was completely obtained. Then, it was immersed in a ₃ M NaCl aqueous solution at 50 ° C. for 4 hours to form —SO ₃ Na type, and the substituted proton (H ⁺ ) was neutralized with 0.2 N NaOH to determine the acid group concentration.

(3) Moisture content After removing the H-type ion exchange membrane stored in water at room temperature from the water and wiping it lightly (after about 1 minute), the weight of the membrane is defined as W _s (g). When the weight W _d (g) of the film when vacuum-dried at 60 ° C. for 16 hours is defined as the dry weight, the water content can be obtained from W _s and W _d by the following equation.

(4) Electrical conductivity The electrical conductivity of the ion exchange membrane is measured by the AC method (New Experimental Chemistry Course 19, Polymer Chemistry <II>, p.992, Maruzen). Membrane resistance (R _m ) was measured using a LCR meter, E-4925A, manufactured by Let Packard. The cell was filled with a 1M aqueous sulfuric acid solution, and the resistance between platinum electrodes (distance 5 mm) depending on the presence or absence of the film was measured. The electric conductivity (specific conductivity) of the film was calculated using the following equation.

Cell and potentiostats and functions similar to those of Mark W. Verbrugge, Robert F. Hill et al. (J. Electrochem. Soc., 137, 3770-3777 (1990)) by DC method for comparison of electrical conductivity measurements. Measured using a generator. There was a good correlation between the measured values of the AC and DC methods. The values in Table 1 below are measured values by the AC method.

(5) Oxidation resistance (weight residual rate%)
The weight of the ion exchange membrane after vacuum drying at 60 ° C. for 16 hours is defined as W _3, and the weight after drying of the ion exchange membrane treated with a 3% hydrogen peroxide solution at 80 ° C. for 24 hours is defined as W ₄ .

(6) Film length swelling degree (%)
The length of one side of a sulfonic acid type membrane in a wet state (water) at room temperature is L ₀ , and the membrane is immersed in a methanol solution under predetermined conditions, and then the same piece of the membrane in a methanol solution wet state at room temperature If the length of L is L _M

Example 1
An irradiation device (inner diameter 60 cmφ × high) of polyethylene terephthalate (hereinafter abbreviated as PET) film base (thickness 38 μm, manufactured by Hoechst) 10 cm × 10 cm in the beam line of the AVF cyclotron accelerator (Japan Atomic Energy Research Institute, Takasaki Research Laboratory) The inside of the container was degassed to 10 ⁻⁶ Torr and irradiated with 450 MeV, Xe (xenon) ions at 3 × 10 ⁸ ions / cm ² . The ion current was measured in advance by irradiating an ion beam on the same irradiation table, and the irradiation amount was obtained by measuring the charge amount of the ions transmitted through the film being irradiated.

Take out the film from the irradiation container, quickly cut it into 2cm x 2cm, put it in a separable container made of glass with a cock (inner diameter 3cmφ x height 15cm), then 1,2,2-trifluoroethylenesulfonyl fluoride ( CF ₂ = CF (SO ₂ F)) was added until the film was immersed, and freeze deaeration was repeated to remove the monomer liquid and air in the perforated film. Finally, the inside of the glass container was replaced with argon gas and sealed. In this state, the glass container was kept at 60 ° C. for 48 hours, and then the film was taken out, washed with toluene and then with acetone, and dried under reduced pressure. The graft ratio of the film calculated | required by Formula (1) was 17%.

  This grafted PET film was reacted at 80 ° C. for 24 hours in a methanol / water (1: 2) solution of 20 wt% KOH. After the reaction, the film was taken out, washed with water, and treated in a 2N sulfuric acid solution at 60 ° C. for 4 hours. The graft ratio, ion exchange capacity (formula (2)), moisture content (formula (3)), and electrical conductivity (formula (4)) of the polymer ion membrane obtained in this example are shown in Table 1 below. Shown in

(Example 2)
In the same manner as in Example 1, 3 × 10 ⁸ ions / cm ^{2 were} irradiated with 450 MeV and Xe (xenon) ions. The obtained ion-irradiated PET film substrate was cut into 2 cm × 2 cm and placed in a glass separable container with a cock (inner diameter 3 cmφ × height 15 cm), and further 1,2,2-trifluoroethylenesulfonylmethoxide ( CF ₂ ═CF (SO ₃ CH ₃ )) was added until the film was immersed, and freeze deaeration was repeated to remove monomer liquid and air in the film. Finally, the inside of the glass container was replaced with argon gas and sealed. The glass container was allowed to stand at 60 ° C. for 48 hours, and then the film was taken out, washed with toluene and then with acetone, and further dried under reduced pressure. The graft ratio of the film calculated | required by Formula (1) was 22%.

  This grafted PET film was reacted at 20% by weight in a propanol / water (1: 2) solution of KOH at 80 ° C. for 12 hours. After the reaction, the film membrane was taken out, washed with water, and treated in a 1N sulfuric acid solution at 60 ° C. for 4 hours. The graft ratio, ion exchange capacity, water content, and electrical conductivity of the polymer ion exchange membrane obtained in this example are shown in Table 1 below.

(Example 3)
In the same manner as in Example 1, 3 × 10 ⁸ ions / cm ^{2 of} 520 MeV and Kr (krypton) ions were irradiated. The obtained ion-irradiated PET film was cut into 2 cm × 2 cm and placed in a glass separable container with a cock (inner diameter 3 cmφ × height 15 cm), and then 1,2,2-trifluoroethylenesulfonyl fluoride (CF ₂ = CFSO ₂ F) and methyl-1,2,2-trifluoroacrylate (CF ₂ = CFCOOCH ₃ ) in a volume ratio of 3: 2 are added until the film is immersed, and freeze degassing is repeated until the monomer liquid or film The air was removed. Finally, the inside of the glass container was replaced with argon gas and sealed. In this state, the glass container was kept at 60 ° C. for 48 hours, and then the film was taken out, washed with toluene and then with acetone, and dried under reduced pressure. The graft ratio of the film determined by the formula (1) was 36%.

  This grafted PET film was reacted for 24 hours at 80 ° C. in an isopropanol / water (1: 2) solution of 20 wt% KOH. After the reaction, the film was taken out, washed with water, and treated in a 2N sulfuric acid solution at 60 ° C. for 4 hours. The graft ratio, ion exchange capacity, water content, and electrical conductivity of the polymer ion exchange membrane obtained in this example are shown in Table 1 below.

Example 4
In order to obtain a crosslinked polyvinylidene fluoride (hereinafter abbreviated as PVDF) film, the following irradiation was performed. A 25 cm thick polyvinylidene fluoride film substrate (manufactured by Kureha Chemical) was placed in a 10 cm x 10 cm SUS autoclave irradiation vessel (inner diameter 7 cmφ x 30 cm in height), and the inside of the vessel was degassed to 10 ^-3 Torr and argon gas Replaced with Thereafter, the PVDF film was irradiated with ⁶⁰ Co-γ rays at room temperature at a dose rate of 5 kGy / h and a dose of 500 kGy (100 hours). After irradiation, when the gelation rate of the crosslinked state of the PVDF film was measured with a dimethylformamide solvent, it was 80%.

The crosslinked PVDF film substrate was irradiated in the same manner as in Example 1 in an amount of 3 × 10 ⁸ ions / cm ² of 450 MeV and Xe ions. After the ion irradiation, the PVDF film substrate is quickly cut into 2 cm × 2 cm, put into a glass separable container with a cock (inner diameter 3 cmφ × height 15 cm), and further, 1,2,2-trifluoroethylenesulfonyl fluoride ( CF ₂ = CF (SO ₂ F)) and methyl-1-fluoroacrylate (CH ₂ = CF (COOCH ₃ )) mixed in a volume ratio of 3: 1 are added until the film is immersed, and freeze deaeration is repeated. Monomer liquid and air in the film were removed. Finally, the inside of the glass container was replaced with argon gas and sealed. In this state, the glass container was left at 60 ° C. for 48 hours, and then the film was taken out, washed with toluene, then with acetone, and further dried under reduced pressure. The graft ratio of the film calculated | required by Formula (1) was 27%.

  This grafted PVDF film was reacted at 20% by weight in a dimethyl sulfoxide / water (1: 2) solution of KOH at 80 ° C. for 24 hours. After the reaction, the film membrane was taken out, washed with water, and treated in a 2N sulfuric acid solution at 60 ° C. for 4 hours. The graft ratio, ion exchange capacity, moisture content, and electrical conductivity of the polymer ion membrane obtained in this example are shown in Table 1 below.

(Example 5)
In the same manner as in Example 1, 3 × 10 ⁸ ions / cm ^{2 were} irradiated with 450 MeV and Xe (xenon) ions. The obtained ion-irradiated PET film substrate was cut into 2 cm × 2 cm, placed in a glass separable container with a cock (inner diameter 3 cmφ × height 15 cm), and further styrene (CH ₂ = CH (C ₆ H ₅ )). And a solution of 5 vol% divinylbenzene in a 2: 1 volume ratio solution of vinyl toluene (CH ₂ ═CH (C ₆ H ₄ (CH ₃ )) until the film is immersed, and freeze degassing is repeated until monomer The solution and the air in the perforated film were removed, and the inside of the glass container was replaced with argon gas and sealed.In this state, the glass container was left at 60 ° C. for 16 hours, and then the film was taken out and toluene was removed. The film was then washed with acetone and dried under reduced pressure, and the graft ratio of the film determined by the formula (1) was 73%.

  The grafted PET membrane was sulfonated by standing at room temperature for 12 hours with a 0.5 molar chlorosulfonic acid solution (the solvent was 1,2-dichloroethane) at room temperature. Table 1 shows the graft ratio, ion exchange capacity, water content, and electrical conductivity of the polymer ion membrane obtained in this example.

(Example 6)
In order to obtain a crosslinked polytetrafluoroethylene (hereinafter abbreviated as PTFE) film, the following irradiation was performed. Place a 10cm x 10cm square of 50µm thick PTFE film (Nitto Denko) into a SUS autoclave irradiation container (inner diameter 7cmφ x height 30cm) with a heater, and degas the container to 10 ^-3 Torr with argon gas Replaced with Then, the temperature of the PTFE film was set to 340 ° C. by heating with an electric heater, and ⁶⁰ Co-γ rays were irradiated at a dose rate of 3 kGy / h and a dose of 90 kGy (30 hours). After irradiation, the container was cooled and the PTFE film was taken out. The crosslinked PTFE film obtained by this high-temperature irradiation shows that the crystal size is considerably smaller than that of uncrosslinked PTFE because the transparency of the film is increased.

This crosslinked PTFE film was irradiated with 20 MeV of carbon ions at 4 × 10 ⁸ ions / cm ^{2 on} the surface of the film substrate in the same manner as in Example 1, and 120 MeV Ar (argon) on the other surface (back surface). ) Ion was irradiated with 3 × 10 ⁸ ions / cm ² . The ion-irradiated PTFE film is cut into 2 cm × 2 cm, put into a glass separable container with a cock (inner diameter 3 cmφ × height 15 cm), and further styrene (CH ₂ ═CH (C ₆ H ₅ )) and vinyltoluene. A solution of (CH ₂ = CH (C ₆ H ₄ (CH ₃ ))) in a volume ratio of 2: 1 is added with a solution of 5 vol% divinylbenzene until the film is immersed, and freeze degassing is repeated until the monomer solution or Air in the perforated film was removed. Finally, the inside of the glass container was replaced with argon gas and sealed. In this state, the glass container was kept at 60 ° C. for 16 hours, and then the film was taken out, washed with toluene and then with acetone, and further dried under reduced pressure. The graft ratio of the film obtained by the formula (1) was 66%.

  The grafted PTFE membrane was sulfonated at room temperature for 12 hours with a 0.5 molar chlorosulfonic acid solution (solvent: 1,2-dichloroethane) at room temperature. Table 1 shows the graft ratio, ion exchange capacity, water content, and electrical conductivity of the polymer ion membrane obtained in this example.

(Example 7)
The crosslinked PVDF film obtained by the same method as in Example 4 was irradiated with 30 MeV of carbon ions and 5 × 10 ⁸ pieces / cm ^{2 in} the same apparatus as in Example 1. The ion-irradiated PVDF film is cut to 2 cm x 2 cm and placed in a glass separable container with a cock (inner diameter 3 cmφ x height 15 cm), and 0.5 mol of chlorosulfonic acid solution (solvent is 1,2-dichloroethane) Until the film is immersed. The glass container was sealed and allowed to stand at room temperature for 24 hours to sulfonate the film.

  The ion exchange capacity, water content, and electric conductivity of the polymer ion membrane obtained in this example are shown in Table 1 below.

(Example 8)
The degree of swelling of the polymer ion exchange membrane with alcohol was measured. The membranes obtained in Examples 1 to 7 and Nafion 117 (manufactured by DuPont) were dipped in a 3N sulfuric acid solution to make the sulfonic acid group H-shaped. Subsequently, it was immersed in room temperature water, and the dimension was measured in the wet state. Next, the membrane was immersed in an aqueous 80 vol% methanol concentration and held at 60 ° C. for 3 hours, and then allowed to cool to room temperature overnight, and then the dimensional change of the membrane was measured. The results are shown in Table 1. The membrane obtained in this example is very effective as a membrane material for a direct methanol fuel cell because the membrane is hardly swollen by methanol as compared with the Nafion membrane.
Table 1 demonstrates the effectiveness of the present invention.

(Comparative Examples 1 and 2)
The results of ion exchange capacity, water content, and electrical conductivity measured for Nafion 115 and Nafion 117 (both manufactured by DuPont) shown in Table 1 below are shown in Comparative Examples 1 and 2 in Table 1.

(Comparative Example 3)
The crosslinked PTFE film (thickness 50 μm) obtained by the same method as in Example 6 was put in a glass separable container (inner diameter 3 cmφ × height 15 cm) with a cock, and then replaced with argon gas. In this state, the crosslinked PTFE film was again irradiated with γ rays (dose rate 10 kGy / h) at 45 kGy at room temperature. Styrene monomer, in which oxygen was removed by bubbling with argon gas and substituted with argon gas, was introduced into a glass container containing a crosslinked PTFE film until the membrane was immersed. The container was stirred and reacted at 60 ° C. for 6 hours. Thereafter, the graft copolymer membrane was washed with toluene and then with acetone and dried. The graft rate was 93%. This graft polymerized membrane was immersed in a 0.5 M chlorosulfonic acid solution (the solvent was 1,2-dichlorotan) and subjected to sulfonation reaction at 60 ° C. for 24 hours. Thereafter, this membrane was washed with water to obtain sulfonic acid groups.

Claims (8)

One surface of the polymer film substrate is irradiated with 10 ⁴ to 10 ¹⁴ ions / cm ^{2 of} hydrogen ions, helium ions, or high-energy heavy ions having a range less than the film thickness , and the other surface is exposed to the flying in the film. CF ₂ = a monomer having a sulfonyl halide group on the film substrate by irradiating the same or different ions having a range of less than or equal to the film thickness with the irradiation amount changed within the above range. CF (SO ₂ X ¹ ) (wherein X ¹ is a halogen group —F or —Cl; the same shall apply hereinafter), CH ₂ ═CF (SO ₂ X ¹ ), and CF ₂ ═CF (OCH ₂ ( CF ₂ ) ₁ to ₄ SO ₂ X ¹ ) One or two or more types of monomers selected from the group consisting of CF ₂ ) ₁ and two or more types of monomers are added, heated after degassing, the monomers are graft polymerized onto the film substrate, and the grafted molecules Halogen group [—X ¹ ] in the chain is converted to sulfonic acid A polymer ion, characterized in that it is a salt [—SO ₃ M] (wherein M is an alkali metal and is Na or K), and then the sulfonate group is a sulfonate group [—SO ₃ H]. An exchange membrane manufacturing method. Furthermore, CF ₂ ═CR ² (COOR ³ ) (wherein R ² is —CH ₃ or —F, and R ³ is —H, —CH ₃ , —C ₂ H ₅ or —C, which is an acrylic monomer. (CH ₃ ) _{3. The} same shall apply hereinafter.) And one or more comonomers selected from the group consisting of CH ₂ ═CR ² (COOR ³ ) and added in an amount of 50 mol% or less based on the total monomers. The method for producing a polymer ion exchange membrane according to claim 1, which is polymerized. Polymer film base material is polyethylene terephthalate, ultra high molecular weight polyethylene, polypropylene, polystyrene, polyamide, aromatic polyamide, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyether ketone, polyether ether ketone, polyether sulfone, polyphenylene sulfide, Or the manufacturing method of the polymer ion exchange membrane of Claim 1 or 2 which is a polysulfone film base material. The method for producing a polymer ion exchange membrane according to claim 1 or 2 , wherein the polymer film substrate is a polyimide, polyetherimide, polyamideimide, polybenzimidazole, or polyetheretherimide film substrate. Polymer film substrate is polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer film The manufacturing method of the polymer ion exchange membrane of Claim 1 or 2 which is a base material. The method for producing a polymer ion exchange membrane according to any one of claims 1 to 5 , wherein the polymer film substrate has a crosslinked structure. Further, one or more selected from the group consisting of divinylbenzene, triallyl cyanurate, triallyl isocyanurate, 3,5-bis (trifluorovinyl) phenol, and 3,5-bis (trifluorovinyloxy) phenol The method for producing a polymer ion exchange membrane according to any one of claims 1 to 6 , wherein the crosslinking agent is added in an amount of 30 mol% or less based on the total amount of monomers to cause graft polymerization. The method for producing a polymer ion exchange membrane according to any one of claims 1 to 7 , wherein the graft ratio is 10 to 120% and the ion exchange capacity is 0.3 to 2.5 meq / g. .