JP2002231270A - Manufacturing method of ion exchange resin membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an ion exchange resin membrane insoluble in water and usable for a fuel cell while having little dimensional change caused by water absorption and dehydration. SOLUTION: A metal oxide precursor is added to a solution containing an ion exchange resin, and a liquid is obtained by applying hydrolysis and polycondensation reaction to the metal oxide precursor. This ion exchange resin membrane is manufactured by forming the liquid into a membrane by casting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an ion exchange resin membrane used for a fuel cell.

[0002]

2. Description of the Related Art An ion exchange resin is a polymer material having a strong acid group such as a sulfonic acid group or a carboxylic acid group in a polymer chain, and has a property of selectively transmitting specific ions. It is used in various applications such as polymer electrolyte fuel cells, chloralkali, water electrolysis, hydrohalic acid electrolysis, salt electrolysis, oxygen concentrators, humidity sensors, gas sensors and the like. Among them, fuel cells convert chemical energy of fuel into electric energy by electrochemically oxidizing hydrogen, methanol, and the like, and are attracting attention as a clean electric energy supply source.

Incidentally, an ion exchange resin membrane used in such a fuel cell is required to exhibit high ionic conductivity. JP-A-4-366137 discloses that the ion conductivity of an ion-exchange resin membrane largely depends on the water content of the membrane.
It is reported in JP-A-6-342665, and it is known that an ion exchange resin membrane having a higher water content has a higher ionic conductivity. Therefore, when used for a fuel cell, a device has been devised to reduce the electrical resistance during power generation by achieving high ionic conductivity by using an ion exchange resin membrane having a high water content.

However, the ion exchange resin membrane having such a high water content has a large dimensional change due to water absorption and dehydration, and is extremely complicated to handle. Due to the increase and decrease, the ion exchange resin membrane deteriorates due to repeated expansion and contraction, and there is also a problem in terms of long-term durability. On the other hand, the ion conductivity of the ion exchange resin membrane is also greatly dependent on the number of ion exchange groups, and the smaller the dry weight (EW) per equivalent of ion exchange groups, the smaller the number of ion exchange groups. It has been found that an ion-exchange resin membrane having a larger content exhibits a higher ion conductivity. However, even when the EW is small, the dimensional change of the film due to water absorption and dehydration becomes large, and there is a problem that the film is easily dissolved in water or hot water. Therefore, for fuel cells, the EW is usually limited to those having a EW of about 950 to 1200.

Further, a perfluorosulfonic acid-based ion exchange resin membrane is first impregnated with an aqueous alcohol solution such as methanol, and then a mixed solvent of tetraethoxysilane, which is a metal alkoxide, and an alcohol is added. An ion-exchange resin membrane in which ethoxysilane is hydrolyzed and polycondensed and silica is contained in a perfluorosulfonic acid-based ion-resin exchange membrane has also been reported (KA Mauritz, RF Storey and CK Jones, i).
n Multiphase Polymer Materials: Blends and Ionomer
s, LA Utracki and RA Weiss, Editors, ACS Sym
posium Series No. 395, p. 401, American Chemical So
ciety, Washington, DC (1989)). The present inventor evaluated this ion exchange resin membrane, and found that the dimensional change of the membrane due to water absorption and dehydration was reduced. However,
In the production of such an ion-exchange resin membrane containing silica, mass production was extremely difficult because of the swelling process of the ion-exchange resin membrane with an aqueous alcohol solution.

On the other hand, Japanese Patent Application Laid-Open No. Hei 6-11827 discloses a method in which an ion-exchange resin membrane containing fine particles of silica and / or silica fibers is dispersed, and Japanese Patent Application Laid-Open No. 9-251857 discloses a method in which hygroscopic inorganic porous particles are dispersed and mixed. An ion exchange resin membrane is disclosed. The present inventor also examined these ion exchange resin membranes, and found no remarkable effect on dimensional change of the membrane due to water absorption and dehydration and dissolution in water at low EW.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method for producing an ion-exchange resin membrane which can be used in a fuel cell and which has a small dimensional change due to water absorption and dehydration and is hardly dissolved in water even with a small EW. It is intended to provide a method.

[0008]

Means for Solving the Problems As a result of intensive studies by the present inventors, a metal oxide precursor was added to a solution containing an ion exchange resin, and the metal oxide precursor was subjected to hydrolysis and polycondensation reaction. The present invention was found that an ion-exchange resin membrane produced by casting the obtained liquid into a cast membrane has a small dimensional change of the membrane due to water absorption and dehydration, and is difficult to dissolve in water even with a small EW. Was.

That is, the present invention relates to: 1, a liquid obtained by adding a metal oxide precursor to a solution containing an ion exchange resin, and subjecting the metal oxide precursor to hydrolysis and polycondensation reaction; A method for producing an ion-exchange resin membrane, characterized by being formed into a membrane; 2, an ion-exchange resin membrane, characterized by being produced by the above-described method; The present invention relates to a polymer electrolyte fuel cell comprising the membrane electrode assembly, and the ion exchange resin membrane.

Hereinafter, the production of the ion exchange resin membrane of the present invention will be described.
The method will be described in detail. The production method of the present invention
A metal oxide precursor to a solution containing an exchange resin,
Obtained by hydrolysis and polycondensation reaction of metal oxide precursor
How to produce an ion exchange resin membrane by casting a liquid
About the law. The ion exchange resin used in the present invention is a fluorinated resin.
Olefin and ion exchange group precursor (sulfonic acid group precursor
Fluorinated compound having an isomer or a carboxylic acid group precursor)
Fluorocarbon polymer obtained by copolymerizing
(Referred to as an ion exchange resin precursor)
Hydrolyzes the cation-exchange group precursor to form a sulfonic acid group or
To make a fluorocarbon polymer having a boronic acid group
Therefore, it is manufactured. The ion exchange resin precursor is CF_Two=
CX¹X^Two(X¹And X^TwoIs independently a halogen element or charcoal
A perfluoroalkyl group of 1 to 10
A fluorinated olefin represented by the formula:
_Two= CF (-O- (CF_Two−CF (CF _TwoX^Three))_b-O_C−
(CFR¹)_d− (CFR^Two)_e− (CF_Two)_f-X^Five)
Vinyl fluoride compound (c is 0 or 1, d and e and
And f are independently integers from 0 to 6 (where d + e + f is equal to 0)
Not), R¹And R^TwoIs independently a halogen element or charcoal
A perfluoroalkyl group of 1 to 10
A loroalkyl group, X^FiveIs CO_TwoR^Three, COR^FourOr SO_Two
R^Four(R^ThreeIs a hydrocarbon alkyl group having 1 to 3 carbon atoms, R^Four
Is preferably a fluorocarbon copolymer with a halogen element)).
Good.

Representative fluorinated olefins include CF
_Two= CF_Two, CF_Two= CFCl, CF_Two= CCl_TwoBut
It is. As the vinyl fluoride compound, specifically, CF
_Two= CFO (CF_Two)_z-SO_TwoF, CF_Two= CFOCF_TwoC
F (CF_Three) O (CF_Two)_z-SO_TwoF, CF_Two= CF (C
F_Two)_z-SO_TwoF, CF_Two= CF (OCF_TwoCF (C
F_Three))_z-1− (CF_Two)_Two-SO_TwoF, CF_Two= CFO (C
F_Two)_z-CO_TwoR, CF_Two= CFOCF_TwoCF (CF_Three) O
(CF_Two)_z-CO_TwoR, CF_Two= CF (CF_Two)_z-CO _Two
R, CF_Two= CF (OCF_TwoCF (CF_Three))_z− (C
F_Two)_Two-CO_TwoR (z is an integer of 1 to 8, R is 1 to
3 represents a hydrocarbon alkyl group).

[0012] The above fluorocarbon copolymer is
It may be a perfluoroolefin such as hexafluoropropylene or chlorotrifluoroethylene, or a copolymer containing a third component such as perfluoroalkylvinyl ether. As a method for polymerizing such an ion exchange resin precursor, a solution polymerization method in which the vinyl fluoride compound is dissolved in a solvent such as chlorofluorocarbon and then reacted with a fluorinated olefin gas to perform polymerization, a solvent such as chlorofluorocarbon is used. A bulk polymerization method in which a vinyl fluoride compound is charged into water together with a surfactant and emulsified, followed by a reaction with a fluorinated olefin gas for polymerization, and the like. The ion exchange resin precursor is represented by the following formula (1). _{^{- [CF 2 CX 1 X 2}} ] a - [CF 2 -CF (-O- (CF 2 -CF (CF 2 X 3)) b -O C - (CFR 1) d - (CFR 2) e - ( CF ₂ ) _f -X ⁵ )]-(1) (wherein X ¹ , X ² and X ³ are each independently a halogen element or a perfluoroalkyl group having 1 to 3 carbon atoms, a is an integer of 0 to 20, b is an integer of 0 to 8, c is 0 or 1, d and e and f are each independently an integer of 0 to 6 (however, d + e + f is not equal to 0), and R ¹ and R ² are each independently a halogen element or carbon number. 1 to 10 perfluoroalkyl groups or fluorochloroalkyl groups, and X ⁵ is CO ₂ R ³ , COR ⁴ , or SO ₂ R ⁴
(R ³ is a hydrocarbon alkyl group having 1 to ³ carbon atoms, and R ⁴ is a halogen element)

Next, the ion exchange resin precursor is hydrolyzed by bringing the ion exchange resin precursor produced by the above method into contact with an alkaline solution to produce an ion exchange resin. The hydrolysis of the ion exchange group precursor can be carried out in an aqueous alkali hydroxide solution, and it is advantageous to use a solution having a relatively high temperature in order to further increase the hydrolysis reaction rate. For example, there is a method disclosed in JP-A-61-19638 in which an aqueous solution containing 20 to 25% of sodium hydroxide is subjected to a hydrolysis treatment at 70 to 90 ° C. for 16 hours. In addition, in order to swell the membrane and accelerate the hydrolysis reaction rate, a mixture of an aqueous alkali hydroxide solution and an alcoholic solvent such as methyl alcohol, ethyl alcohol and propyl alcohol, or a water-soluble organic solvent such as dimethyl sulfoxide is used. Decomposition methods are used. For example, Japanese Patent Application Laid-Open No. 57-13912
JP-A-3-6240 discloses a method of hydrolyzing for 1 hour at 90 ° C. using an aqueous solution containing 11 to 13% of potassium hydroxide and 30% of dimethyl sulfoxide. % And an aqueous solution containing 0.1 to 30% by weight of a water-soluble organic compound.
This is a method of performing a hydrolysis treatment at 20 ° C for 20 minutes to 24 hours.

After forming an ion-exchange group by the hydrolysis treatment as described above, the resultant is washed with water to be represented by the following formula (2) having an alkali-metal-type ion-exchange group or an alkaline-earth-metal-type ion-exchange group. An ion exchange resin can be obtained. Further, by performing an acid treatment with an inorganic acid such as hydrochloric acid, an ion exchange resin having an acid type ion exchange group can be produced. _{^{- [CF 2 CX 1 X 2}} ] a - [CF 2 -CF (-O- (CF 2 -CF (CF 2 X 3)) b -O C - (CFR 1) d - (CFR 2) e - ( ^{_{CF 2) f -X 4)]}} - (2) (X 1, X 2 and X ³ are independently perfluoroalkyl group of halogen or 1 to 3 carbon atoms in the formula, a is 0 to 20 integer, b is an integer of 0 to 8, c is 0 or 1, d and e and f are independently an integer of 0 to 6 (however, d + e + f is not equal to 0), and R ¹ and R ² are independently a halogen element or a carbon number. 1 to 10 perfluoroalkyl groups or fluorochloroalkyl groups, X ⁴ is COOZ or SO ₃ Z (Z is an alkali metal atom, or an alkaline earth metal atom, or a hydrogen atom)

Although the EW of the ion exchange resin used in the production method of the present invention is not particularly limited, it is 250 to 1200, preferably 250 to 1000, more preferably 250 to 800, still more preferably 25 to 800.
It is 0 or more and 700 or less. Next, the ion exchange resin produced by the above method is dissolved in water, a non-aqueous solvent, or a mixed solvent of water and a non-aqueous solvent by a general method to form a solution. The non-aqueous solvent referred to herein is not particularly limited, but alcohol solvents such as methanol, ethanol, and isopropanol are preferable. The term “solution” as used herein also includes a state in which the ion exchange resin is dispersed in a micelle. When the ion exchange resin is difficult to dissolve, it can be dissolved under heating or under pressure in an autoclave or the like.

Further, a metal oxide precursor is added to the solution containing the ion exchange resin. The amount of the metal oxide precursor to be added is not particularly limited.
0.01 to 200 equivalents, preferably 0.1 to 1
The equivalent amount is at most 00 equivalent, more preferably at least 0.1 and at most 50 equivalents, even more preferably at least 0.1 and at most 20 equivalents.

The metal oxide precursor used in the present invention is particularly limited.
Not specified, Al, B, P, Si, Ti, Zr, Y
Alkoxides containing are preferred. Al alkoxy
As a specific example of C, Al (OCH_Three)_Three, Al (OC_Two
H_Five)_Three, Al (OC_ThreeH₇)_Three, Al (OC_FourH₉)_Three, B
As a specific example of the alkoxide contained, B (OC
H_Three)_ThreeSpecific examples of alkoxides containing P
Is P (OCH_Three)_ThreeOf alkoxides containing Si
As a specific example, Si (OCH_Three)_Four, Si (OC_TwoH_Five)
_Four, Si (OC_ThreeH₇)_Four, Si (OC_FourH₉)_Four, Including Ti
Specific examples of the alkoxides include Ti (OC
H_Three)_Four, Ti (OC_TwoH_Five)_Four, Ti (OC_ThreeH₇)_Four, T
i (OC_FourH₉)_FourSpecific examples of alkoxides containing Zr
As an example, Zr (OCH_Three)_Four, Zr (OC_TwoH_Five)_Four,
Zr (OC_ThreeH₇)_Four, Zr (OC_FourH₉)_FourIs mentioned.
Specific examples of the alkoxide containing Y include Y (OC
_FourH₉)_ThreeIs mentioned. These can be used alone,
Two or more kinds may be mixed and used. Also, La
[Al (i-OC_ThreeH₇)_Four]_Three, Mg [Al (i-OC
_ThreeH₇)_Four]_Two, Mg [Al (sec-OC_FourH₉)_Four]_Two, Ni
[Al (i-OC_ThreeH₇)_Four]_Two, (C_ThreeH₇O) _TwoZr [Al
(OC_ThreeH₇)_Four]_Two, Ba [Zr_Two(OC_TwoH_Five)₉]_Twosuch as
Bimetallic alkoxides may be used.

When the solution containing the ion exchange resin contains water, hydrolysis and polycondensation of the metal oxide precursor start simultaneously with the addition of the metal oxide precursor. When the solution containing the ion exchange resin is non-water or has a low water content, the metal oxide precursor is added, water is added after stirring, and the metal oxide precursor is hydrolyzed and polycondensation reaction is started. The amount of water is not particularly limited, but is 1 equivalent to 100 equivalents, preferably 2 equivalents to 80 equivalents, more preferably 3 equivalents to 50 equivalents, and still more preferably 3 equivalents to 1 equivalent of the metal oxide precursor. It is equal to or more than 30 equivalents.

The reaction temperature is not particularly limited,
Preferably 1 ° C or higher and 100 ° C or lower, more preferably 10 ° C or lower.
C. to 80.degree. C., more preferably 20.degree. C. to 50.
It is below ° C. The above temperature may be set from the time of addition of the metal oxide precursor. The reaction time is not particularly limited, but is preferably from 1 second to 24 hours, more preferably from 30 seconds to 8 hours, and still more preferably from 1 minute to 1 hour. As the hydrolysis and polycondensation reaction of the metal oxide precursor progresses, the viscosity of the solution increases.

In order to impart flexibility to the ion-exchange resin membrane formed using the ion-exchange resin solution of the present invention, it is possible to add an organic silicon compound simultaneously with the addition of the metal oxide precursor. The organic silicon compound is not particularly limited, for example, trimethylchlorosilane, dimethyldichlorosilane, a silylating agent such as hexamethyldisilazane, vinyltrichlorosilane, a silane coupling agent such as vinyltrimethoxysilane, other, ethyldichlorosilane, Ethyltrichlorosilane, dimethyldichlorosilane, tetraisocyanatesilane, tetramethylsilane, trichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, methyldichlorosilane, methyltrichlorosilane, monomethyltriisoisanatosilane, diethoxydimethylsilane, and the like.

In order to prevent cracking of the ion exchange resin membrane, a drying control agent may be added. The drying control agent is not particularly limited, but includes dimethylformamide, formamide and the like. A liquid obtained by adding a metal oxide precursor to the solution containing the ion exchange resin produced as described above and subjecting the metal oxide precursor to hydrolysis and polycondensation reaction is cast on a substrate to form a film. By doing so, an ion exchange resin membrane can be obtained. The viscosity of the liquid is not particularly limited, but is preferably from 1 to 100,000 cps. Further, the liquid may contain an unreacted metal oxide precursor.

The casting method is not particularly limited. For example, gravure roll coater, natural roll coater, reverse roll coater, knife coater, dip coater
For example, a known coating method can be used. The substrate is not particularly limited, but may be a general polymer film, a metal foil, a substrate of alumina or Si, a porous film obtained by stretching a PTFE film described in JP-A-8-162132, Fibrillated fibers and the like described in JP-B-53-149881 and JP-B-63-61337 can be used.

After the casting, drying and / or heat treatment is performed by a known method such as hot air drying to solidify, thereby obtaining an ion exchange resin membrane. When the ion-exchange resin membrane formed in this way is used for a fuel cell, there are cases where the ion-exchange resin membrane is used alone, and cases where the ion-exchange resin membrane is peeled off from the substrate and only the ion-exchange resin membrane is used. is there. Although the EW of the ion exchange resin membrane obtained by the production method of the present invention is not particularly limited, it is 250 or more and 1200 or less, preferably 25 or less.
0 to 1000, more preferably 250 to 800
Hereinafter, it is even more preferably 250 or more and 700 or less. The thickness is not particularly limited, but is preferably 1 μm or more to reduce the gas permeability and 500 μm or less to reduce the electric resistance during power generation.

The ion exchange resin membrane obtained by the production method of the present invention contains a metal oxide. As metal oxides,
Although not particularly limited, Al, B, P, Si, Ti, Z
An oxide composed of r and Y is preferable. The content of the metal oxide is not particularly limited. However, in order to obtain an ion exchange resin membrane that is not dissolved in water and has a small dimensional change due to water absorption and dehydration, 1 wt% or more and sufficient proton conductivity are obtained. For this purpose, the content is preferably 90 wt% or less. More preferably, 2 wt% or more and 70 wt% or less,
Still more preferably, it is 5 wt% or more and 50 wt% or less.

Further, by appropriately using the production method of the present invention, it is possible to obtain an ion-exchange resin membrane having a small dimensional change of the membrane due to water absorption and dehydration. The dimensional change here means that the film area after immersion in water at 30 ° C. for 24 hours and the film area after drying under reduced pressure at 30 ° C. for 8 hours are measured and expressed as a change rate. To evaluate. When used in a fuel cell, it is not particularly limited in order to satisfy durability, but is preferably 100% or less, more preferably 50% or less, and still more preferably 30% or less.

Further, by appropriately using the production method of the present invention, it is possible to obtain an ion-exchange resin membrane which is hardly soluble in water even if the EW is small. Solubility in water is 9
Evaluation is made based on the weight loss rate of the film before and after immersion in water at 0 ° C. for 8 hours. When used for a fuel cell, there is no particular limitation,
It is preferably at most 5%, more preferably at most 2%, even more preferably at most 1%. Next, a case where the ion exchange resin membrane obtained by the production method of the present invention is used for a fuel cell will be described.

When the ion exchange resin membrane of the present invention is used in a polymer electrolyte fuel cell, it is used as a membrane electrode assembly (MEA) in which two types of electrodes, an anode and a cathode, are joined on both sides. The electrode is composed of fine particles of catalytic metal and a conductive agent carrying the fine particles, and optionally contains a water repellent. The catalyst used for the electrode is not particularly limited as long as it promotes the oxidation reaction of hydrogen and the reduction reaction of oxygen.Platinum, gold, silver, palladium, iridium, rhodium, ruthenium, iron, cobalt, nickel, chromium , Tungsten, manganese, vanadium or alloys thereof. Among them, platinum is mainly used. In order to manufacture an MEA from the electrodes and the ion exchange resin membrane of the present invention, for example, the following method is performed. Platinum-supporting carbon serving as an electrode substance is dispersed in a solution in which a fluorine-based ion exchange resin is dissolved in a mixed solution of alcohol and water to form a paste. A predetermined amount of this is applied to a PTFE sheet and dried. Next, the application surfaces of the PTFE sheet are faced to each other, and an ion exchange resin membrane is sandwiched therebetween, and transfer bonding is performed by hot pressing. The hot pressing temperature depends on the type of the ion exchange resin membrane, but is usually 100 ° C. or higher, preferably 130 ° C. or higher, more preferably 150 ° C. or higher.

The polymer electrolyte fuel cell includes the MEA, the current collector, the fuel cell frame, the gas supply device and the like manufactured as described above. Among these, the current collector (bipolar plate) is a graphite or metal flange having a gas flow path on the surface and the like, and supplies hydrogen and oxygen to the MEA surface in addition to transmitting electrons to an external load circuit. It has a function as a flow path. A fuel cell is manufactured by inserting an MEA between such current collectors and stacking a plurality of them. The operation of the fuel cell is performed by supplying hydrogen to one electrode and oxygen or air to the other electrode. The higher the operating temperature of the fuel cell is, the higher the catalyst activity becomes.
It is often operated at 0 ° C to 100 ° C.
It may be operated at 0 ° C. The higher the supply pressure of oxygen or hydrogen is, the higher the output of the fuel cell is.
It is preferable to adjust the pressure to an appropriate range so that the membrane is not damaged.

The ion-exchange resin membrane formed from the ion-exchange resin solution of the present invention can be used in addition to a fuel cell, such as chloralkali, water electrolysis, hydrohalic acid electrolysis, salt electrolysis, oxygen concentrator, humidity sensor, gas sensor, It can also be used for sensors and the like.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples.

[0031]

Example 1 CF ₂ CF ₂ was used as an ion exchange resin precursor.
And _{CF 2 = CFOCF 2 CF (CF} 3) O (CF 2) 2 -S
A fluorocarbon copolymer with O ₂ F was used. The EW of this ion exchange resin precursor is 614, JIS K-72
The melt index (MI (g / 10 min)) measured at a temperature of 270 ° C. and a load of 2.16 kg based on the sample No. 10 is 4
4230. This ion-exchange resin precursor was melt-extruded and molded into a thickness of about 500 μm to form a molded product of about 1 g.
A reaction liquid containing 5% by weight of potassium hydroxide, 30% by weight of dimethylsulfoxide and 55% by weight of water contains 60%
C. for 4 hours to carry out a hydrolysis treatment.

Then, it is washed with ion-exchanged water at 30 ° C.
Next, after being immersed in a 2N hydrochloric acid aqueous solution at 30 ° C. for 3 hours, the acid was washed out with ion-exchanged water to obtain an ion-exchange resin having a sulfonic acid group. Tetraethoxysilane and methanol were mixed at a weight ratio of 1: 1 to 2 g of a 50% solution of this ion exchange resin in ion exchange water at 60 ° C.
4 g of the mixed solvent was added and stirred to start hydrolysis and polycondensation reaction. The liquid was stirred at 60 ° C. to progress the reaction, and when the liquid became highly viscous, the liquid was poured into a petri dish. After drying this liquid at room temperature overnight, it was heat-treated at 110 ° C. to obtain an ion exchange resin membrane of the present invention.

Next, the film was vacuum-dried at 30 ° C. for 8 hours, and the film weight W ₁ (g) was measured. After weighing, the membrane was put again in ion-exchanged water and immersed at 90 ° C. for 8 hours. After cooling, the membrane was taken out of the water and washed with ion-exchanged water. Then, the film was dried again in vacuum at 30 ° C. for 8 hours, and the film weight W ₂ (g) was measured. The weight loss rate Y (%) due to the boiling treatment on a dry weight basis before the boiling treatment was calculated by the following formula, and the weight loss rate was 4%. Y = (W ₁ −W ₂ ) / W ₁ × 100

[0034]

Comparative Example 1 An ion-exchange resin prepared in the same manner as in Example 1 was placed in ion-exchanged water as it was, and immersed at 90 ° C. for 8 hours, all of which was dissolved in water.

[0035]

Example 2 CF as an ion exchange resin precursor_TwoC
F_TwoAnd CF_Two= CFOCF_TwoCF (CF _Three) O (CF_Two)_Two−
SO_TwoF and a fluorocarbon copolymer (EW: 67)
3, MI: 2061). Method similar to Example 1
Of an ion exchange resin having about 1 g of a sulfonic acid group.
A molded article was obtained. Put this ion exchange resin in ion exchange water.
2 g of a 50% solution that was boiled and dissolved at 60 ° C
Tetraethoxysilane and methanol in a 1: 1 weight ratio
Add 1.4 g of the mixed solvent mixed in
The dissolution and polycondensation reactions were started. At 60 ° C
When the reaction proceeds with stirring and the liquid becomes highly viscous
Then poured the liquid into the petri dish. Dry this liquid overnight at room temperature
After drying, heat treatment is performed at 110 ° C. to obtain a 100 μm thick invention.
Was obtained.

Next, the membrane was immersed in ion-exchanged water at 30 ° C. for one day, and the membrane was taken out and its dimensions were measured to calculate the membrane area A ₁ . After vacuum drying this film at 30 ° C. for 8 hours, the dimensions of the film were measured again, and the film area A ₂ was calculated.
The dimensional change D between wet and dry states was calculated by the following formula, and was 90%. D = (A ₁ −A ₂ ) / A ₁ × 100

[0037]

Comparative Example 2 An ion exchange resin membrane having a thickness of 100 μm was obtained in the same manner as in Example 1 using the same ion exchange resin precursor as in Example 2. This film was prepared in the same manner as in Example 2,
The dimensional change between wet and dry was measured to be 150%
Met.

[0038]

According to the ion exchange resin membrane obtained by the production method of the present invention, the dimensional change of the membrane due to water absorption and dehydration is small,
Further, since the membrane is hardly soluble in water even when the EW is small, it is very effective for use in fuel cells.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) // C08L 27:12 C08L 27:12 F term (reference) 4F071 AA26 AA67 AG02 AH14 FA05 FB03 FC01 FD02 4F205 AB16 AC05 AG01 GA07 GB01 GC06 GE02 GE24 GF02 HA08 HA14 HA25 HA33 HA45 HC05 5H026 AA06 BB10 CX05

Claims (4)

[Claims] 2. A method according to claim 1, wherein a metal oxide precursor is added to the solution containing the ion exchange resin, and a liquid obtained by subjecting the metal oxide precursor to hydrolysis and polycondensation is cast into a film. To manufacture an ion-exchange resin membrane. 2. An ion exchange resin membrane produced by the method according to claim 1. 3. A membrane electrode assembly comprising the ion exchange resin membrane according to claim 2. 4. A polymer electrolyte fuel cell comprising the ion exchange resin membrane according to claim 2.