JP5266086B2 - Manufacturing method of electrolyte membrane for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolyte membrane for a fuel cell having high durability against methanol in use even at high temperature and high proton-selectivity. <P>SOLUTION: The electrolyte membrane 1 for the fuel cell uses an anodic oxidation film 2 obtained by anodic oxidation of valve metal, and the anodic oxidation film 2 includes through-holes 3 having an average hole diameter of 20-200 nm in the depth direction of the anodic oxidation film 2, and a hydrate 4 of the valve metal is formed in at least a part of the through-hole 3. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a method for producing an electrolyte membrane for a fuel cell.

  Among polymer electrolyte fuel cells (PEFC) that use a solid proton exchange membrane as the electrolyte, the type that obtains hydrogen by directly reforming methanol fuel in the cell is easy to downsize, so power supplies for portable devices However, development of a polymer electrolyte membrane having high durability against methanol and high ion (proton) selectivity is demanded.

For example, Patent Document 1 states that “a proton conductive membrane for an electrolyte membrane of a fuel cell, which is a composite of a proton conductive polymer and a polymer represented by the following general formula (1): Proton conducting membrane.

(In the above general formula (1), X is a functional group containing a nitrogen atom, A is a substituted or unsubstituted divalent organic group, and n is an integer).

  Patent Document 2 states that “the metal film or silicon film has a 0.01 to 150 μm diameter through hole provided by anodizing, and a proton conductive functional group is modified on the inner wall of the through hole. This is described as an electrolyte membrane for fuel cells.

  Further, Patent Document 3 discloses an electrolyte membrane in which a pore of a porous substrate that does not substantially swell with an organic solvent containing methanol and water is filled with a first polymer having proton conductivity. The electrolyte membrane is characterized in that the first polymer is a polymer derived from 2-acrylamido-2-methylpropanesulfonic acid. "

JP 2002-110200 A Japanese Patent No. 3932579 JP 2005-71609 A

However, when the proton conductive membranes (electrolyte membranes) described in Patent Documents 1 to 3 are used at high temperatures (for example, about 100 to 180 ° C.), durability against protons and proton selectivity are inferior due to membrane deterioration. I found out that there was a case.
Accordingly, an object of the present invention is to provide a method for producing an electrolyte membrane for a fuel cell that is excellent in methanol durability and proton selectivity even when used at high temperatures.

The present inventor has intensely studied to achieve the above object, using a fine structure obtained by forming a predetermined metal hydrate into the through hole of the average opening diameter of that Jo Tokoro Yusuke is anodized film fuel The present inventors have found that the battery electrolyte membrane has excellent durability against methanol and proton selectivity even when used at a high temperature, and completed the present invention.
That is, the present invention provides the following (1) to ( 3 ).

(1) A method for producing an electrolyte membrane for a fuel cell using an anodized film obtained by anodizing aluminum ,
The anodic oxide film has through holes with an average pore diameter of 20 to 200 nm in the depth direction of the anodic oxide film,
Supplying an alkaline aqueous solution adjusted to pH 9 to 13 to at least a part of the through hole to form the aluminum hydrate ,
A method for producing an electrolyte membrane for a fuel cell , wherein the anodic oxide film having the through-hole formed with the hydrate is fired to oxidize the hydrate .

(2) Further, the manufacturing method of the electrolyte membrane according to the above (1) to fill the hydrophilic polymer having proton conductivity on a part of the through hole.
(3) Oxidizing the aluminum hydrate and transferring it to at least one selected from γ-alumina, Δ-alumina, θ-alumina, α-alumina and η-alumina (1) or (2) The manufacturing method of the electrolyte membrane for fuel cells as described in any one of.

  As will be described below, according to the present invention, it is possible to provide an electrolyte membrane for a fuel cell that is excellent in durability against methanol and proton selectivity even when used at high temperatures.

FIG. 1 is a schematic view for explaining a cross section of an electrolyte membrane for a fuel cell according to the present invention. FIG. 2 is a schematic cross-sectional view illustrating an example of an anodizing process. FIG. 3 is a partial cross-sectional view showing a state after the anodizing treatment. FIG. 4 is a partial cross-sectional view showing a state after the separation process. FIG. 5 is a partial cross-sectional view showing a state after the penetration process. FIG. 6 is an explanatory diagram of a method for calculating the degree of ordering of the through holes.

The present invention is described in detail below.
The method for producing an electrolyte membrane for a fuel cell of the present invention is a method for producing an electrolyte membrane for a fuel cell using an anodized film obtained by anodizing aluminum ,
The anodic oxide film has through holes with an average pore diameter of 20 to 200 nm in the depth direction of the anodic oxide film,
Supplying an alkaline aqueous solution adjusted to pH 9 to 13 to at least a part of the through-hole to form the aluminum hydrate ,
It is a method for producing an electrolyte membrane for a fuel cell , in which the anodic oxide film having the through holes formed with the hydrate is fired to oxidize the hydrate .
Next, the manufacturing method of the electrolyte membrane for fuel cells of this invention is demonstrated using FIG.

FIG. 1 is a schematic view for explaining a cross section of an electrolyte membrane for a fuel cell according to the present invention.
As shown in FIG. 1, an electrolyte membrane 1 for a fuel cell according to the present invention is obtained by forming a hydrate 4 in a through hole 3 of an anodized film 2.
Here, the hydrate 4 may be formed in a part of the through hole 3 as shown in FIGS. 1 (A) and 1 (B), as shown in FIG. 1 (C). Alternatively, it may be formed in the entire through hole 3.
Below, material, a dimension, a formation method, etc. are explained in full detail about each of an anodized film and a hydrate.

[Anodized film]
The anodized film is an anodized film obtained by anodizing a valve metal, and has through holes having an average pore diameter of 20 to 200 nm in the depth direction.

[Valve metal]
The above valve metal has the property that the metal surface is covered with an oxide film of the metal by anodic oxidation, and the oxide film has the property that current flows only in one direction and is very difficult to flow in the reverse direction. Specific examples of the metal include aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony.
Among these, the regularity of the arrangement of micropores (pore arrangement) existing in the anodized film formed by anodizing treatment is improved, and the above-described penetration that can be formed using this micropore Aluminum is preferable because the regularity of the arrangement of the holes is improved, and as a result, the proton selectivity of the electrolyte membrane for a fuel cell of the present invention is further improved.

[Through hole]
The average opening diameter of the through holes of the anodic oxide film is 20 to 200 nm, preferably 25 to 180 nm, and more preferably 30 to 150 nm.
When the average opening diameter of the through holes is within the above range, the proton selectivity of the fuel cell electrolyte membrane of the present invention is further improved.

Similarly, the density of the through holes is preferably 1.5 million pieces / mm ² or more, more preferably 1.8 million to 40 million pieces / mm ² , and 2 million to 30 million pieces / mm ^2. More preferably.
When the average pore diameter and density of the through holes are within the above ranges, the proton selectivity of the fuel cell electrolyte membrane of the present invention is further improved.

The method for forming the anodic oxide film is not particularly limited as long as it can form at least the later-described anodic oxidation treatment and penetration treatment on the valve metal to form a through-hole having the above-mentioned pore diameter, but the following treatments are performed. Is preferably formed.
In addition, in each process shown below, the case where aluminum (board | substrate) is used as said valve | bulb metal is mentioned as an example, and is demonstrated.

[Aluminum (substrate)]
The aluminum substrate is not particularly limited, and specific examples thereof include a pure aluminum plate; an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements; and depositing high-purity aluminum on low-purity aluminum (for example, recycled material). Examples of the substrate include: a substrate in which high purity aluminum is coated on the surface of a silicon wafer, quartz, glass or the like by a method such as vapor deposition or sputtering; a resin substrate in which aluminum is laminated;

  In the present invention, of the aluminum substrate, the surface to be anodized, which will be described later, preferably has an aluminum purity of 99.5% by mass or more, more preferably 99.9% by mass or more, 99 More preferably, it is at least 99 mass%. When the aluminum purity is in the above range, the regularity of the pore arrangement is sufficient.

  Further, in the present invention, the surface of the aluminum substrate to be subjected to anodization described later is preferably subjected to degreasing and mirror finishing in advance, particularly from the viewpoint of improving the regularity of the pore arrangement, Heat treatment is preferably performed.

〔Heat treatment〕
When heat treatment is performed, it is preferably performed at 200 to 350 ° C. for about 30 seconds to 2 minutes. Specifically, for example, a method of placing an aluminum substrate in a heating oven can be used.

[Degreasing]
The degreasing treatment uses acid, alkali, organic solvent, etc. to dissolve and remove the organic components such as dust, fat, and resin adhered to the surface of the aluminum substrate, and in each treatment described later due to the organic components. This is done for the purpose of preventing the occurrence of defects.

Specifically, as the degreasing treatment, for example, a method in which an organic solvent such as various alcohols (for example, methanol), various ketones (for example, methyl ethyl ketone), benzine, volatile oil or the like is brought into contact with the aluminum substrate surface at room temperature (organic Solvent method); a method of bringing a liquid containing a surfactant such as soap or neutral detergent into contact with the aluminum substrate surface at a temperature from room temperature to 80 ° C., and then washing with water (surfactant method); concentration of 10 to 200 g A method in which an aqueous solution of sulfuric acid / L is brought into contact with the aluminum substrate surface at a temperature from room temperature to 70 ° C. for 30 to 80 seconds and then washed with water; while contacting about seconds, the aluminum substrate surface and the electrolyte by passing a direct current of a current density of 1 to 10 a / dm ² in the cathode, the , A method of neutralizing by bringing a nitric acid aqueous solution having a concentration of 100 to 500 g / L into contact; while bringing various known anodizing electrolytes into contact with the aluminum substrate surface at room temperature, the aluminum substrate surface is used as a cathode and a current density of 1 to A method in which a 10 A / dm ² direct current is applied or an alternating current is applied for electrolysis; an alkaline aqueous solution having a concentration of 10 to 200 g / L is brought into contact with the aluminum substrate surface at 40 to 50 ° C. for 15 to 60 seconds; A method of neutralizing by bringing a nitric acid aqueous solution having a concentration of 100 to 500 g / L into contact; an emulsion obtained by mixing light oil, kerosene, etc. with a surfactant, water, etc. is brought into contact with the aluminum substrate surface at a temperature from room temperature to 50 ° C. Then, a method of washing with water (emulsification and degreasing method); a mixed solution of sodium carbonate, phosphates, surfactant and the like on the surface of the aluminum substrate at a temperature from room temperature to 50 ° C. Contacting 0-180 seconds, then, a method of washing with water (phosphate method); and the like.

  Among these, the organic solvent method, the surfactant method, the emulsion degreasing method, and the phosphate method are preferable from the viewpoint that the fat content on the aluminum surface can be removed while the aluminum hardly dissolves.

  Moreover, a conventionally well-known degreasing agent can be used for a degreasing process. Specifically, for example, various commercially available degreasing agents can be used by a predetermined method.

[Mirror finish processing]
The mirror finishing process is performed in order to eliminate unevenness on the surface of the aluminum substrate, for example, rolling streaks generated during the rolling of the aluminum substrate, and improve the uniformity and reproducibility of the sealing process by an electrodeposition method or the like.
In the present invention, the mirror finish is not particularly limited, and a conventionally known method can be used. Examples thereof include mechanical polishing, chemical polishing, and electrolytic polishing.

  Examples of the mechanical polishing include a method of polishing with various commercially available polishing cloths, a method of combining various commercially available abrasives (for example, diamond, alumina) and a buff. Specifically, when an abrasive is used, a method in which the abrasive used is changed from coarse particles to fine particles over time is preferably exemplified. In this case, the final polishing agent is preferably # 1500. Thereby, the glossiness can be 50% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 50% or more).

As chemical polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. Examples thereof include various methods described in 164 to 165.
Further, phosphoric acid - nitric acid method, Alupol I method, Alupol V method, Alcoa R5 _{method, H 3 PO 4 -CH 3 COOH} -Cu _{method, H 3 PO 4 -HNO 3 -CH} 3 COOH method are preferable. Among these, the phosphoric acid-nitric acid method, the H ₃ PO ₄ —CH ₃ COOH—Cu method, and the H ₃ PO ₄ —HNO ₃ —CH ₃ COOH method are preferable.
By chemical polishing, the glossiness can be made 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

As electrolytic polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. 164-165; various methods described in US Pat. No. 2,708,655; “Practical Surface Technology”, vol. 33, no. 3, 1986, p. The method described in 32-38;
By electropolishing, the gloss can be 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

  These methods can be used in appropriate combination. Specifically, for example, a method of performing mechanical polishing in which the abrasive is changed from coarse particles to fine particles with time, and then performing electrolytic polishing is preferable.

By mirror finishing, for example, a surface having an average surface roughness R _{a of} 0.1 μm or less and a glossiness of 50% or more can be obtained. The average surface roughness _Ra is preferably 0.03 μm or less, and more preferably 0.02 μm or less. Further, the glossiness is preferably 70% or more, and more preferably 80% or more.
The glossiness is a regular reflectance obtained in accordance with JIS Z8741-1997 “Method 3 60 ° Specular Gloss” in the direction perpendicular to the rolling direction. Specifically, using a variable angle gloss meter (for example, VG-1D, manufactured by Nippon Denshoku Industries Co., Ltd.), when the regular reflectance is 70% or less, the incident reflection angle is 60 degrees and the regular reflectance is 70%. In the case of exceeding, the incident / reflection angle is 20 degrees.

[Anodizing treatment]
The anodizing treatment is a treatment for forming an anodized film having micropores on the surface of the aluminum substrate by anodizing the aluminum substrate.
As the anodizing treatment, a conventionally known method can be used. Specifically, it is preferable to use a self-ordering method, a constant voltage process, and a constant current process, which will be described later.

The self-ordering method is a method of improving the regularity by utilizing the property that the micropores of the anodized film are regularly arranged and removing the factors that disturb the regular arrangement. Specifically, high-purity aluminum is used, and an anodized film is formed at a low speed over a long period of time (for example, several hours to several tens of hours) at a voltage according to the type of the electrolytic solution.
In this method, since the diameter of the micropore (pore diameter) depends on the voltage, a desired pore diameter can be obtained to some extent by controlling the voltage.

In order to form micropores by the self-ordering method, at least an anodic oxidation process (A) described later may be performed, but an anodic oxidation process (A), a film removal process (B), and a re-anodizing process (C) described later. ) In this order (self-ordering method I), a method in which an anodic oxidation process (D) and an oxide film dissolution process (E) described later are performed at least once in this order (self-ordering method II), etc. It is preferable to do this.
Next, each process of the self-ordering method I and the self-ordering method II, which are preferred embodiments, will be described in detail.

<Self-ordering method I>
(Anodizing treatment (A))
The average flow rate of the electrolytic solution in the anodizing treatment (A) is preferably 0.5 to 20.0 m / min, more preferably 1.0 to 15.0 m / min, and 2.0 to 10 More preferably, it is 0.0 m / min. By performing the anodizing treatment (A) at a flow rate in the above range, uniform and high regularity can be obtained.
Moreover, the method of flowing the electrolytic solution under the above-mentioned conditions is not particularly limited, but, for example, a method using a general stirring device such as a stirrer is used. In particular, it is preferable to use a stirrer that can control the stirring speed by digital display because the average flow velocity can be controlled. Examples of such a stirring apparatus include “Magnetic Stirrer HS-50D (manufactured by AS ONE)” and the like.

For the anodizing treatment (A), for example, a method of energizing an aluminum substrate as an anode in a solution having an acid concentration of 1 to 10% by mass can be used.
The solution used for the anodizing treatment (A) is preferably an acid solution, and hydrochloric acid, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid, glycolic acid, tartaric acid, Malic acid, citric acid, and the like are more preferable, and sulfuric acid, phosphoric acid, and oxalic acid are particularly preferable. These acids can be used alone or in combination of two or more.

  The conditions of the anodizing treatment (A) vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 0.1 to 5.0 M / L, and the solution temperature is −10 to 30 ° C. The electrolyte solution concentration is preferably 0.5 to 5.0 M / L, and the solution temperature is more preferably 0 to 20 ° C.

  The treatment time for the anodizing treatment (A) is preferably 0.5 minutes to 16 hours, more preferably 1 minute to 12 hours, and even more preferably 2 minutes to 8 hours.

The anodizing treatment (A) is preferably performed at a constant voltage, and the treatment voltage is preferably 10 to 300V, more preferably 15 to 260V, and still more preferably 20 to 250V.
In addition to performing under a constant voltage, a method of changing the voltage intermittently or continuously at the final stage of processing can also be used. In this case, it is preferable to decrease the voltage sequentially. This makes it possible to reduce the resistance of the anodized film, and fine micropores are formed in the anodized film, which is preferable in terms of improving uniformity, particularly when sealing treatment is performed by electrodeposition. .

  In the present invention, the film thickness of the anodized film formed by such anodizing treatment (A) is preferably 1 to 300 μm, more preferably 10 to 250 μm, and 30 to 200 μm. Is more preferable.

In the present invention, the average pore diameter of the micropores formed by such anodizing treatment (A) is preferably 0.02 to 0.2 μm, and preferably 0.025 to 0.18 μm. Is more preferable, and it is still more preferable that it is 0.03-0.15 micrometer.
Further, in the micropore formed by such anodizing treatment (A), in the range of 1 μm ² , the dispersion of the pore diameter is preferably within 3% of the average diameter, and more preferably within 2%. preferable. In addition, the average diameter and dispersion | distribution of a pore diameter can each be calculated | required by a following formula.
Average diameter: μ _x = (1 / n) ΣXi
Dispersion: σ ² = (1 / n) (ΣXi ² ) −μ _x ²
Dispersion / average diameter = σ / μ _x ≦ 0.03
Here, Xi is the pore diameter of one micropore measured in the range of 1 μm ² .

Furthermore, in the present invention, the average pore density of micropores in the anodized film formed by such anodizing treatment (A) is preferably 1.5 million pieces / mm ² or more, and 1.8 million to 40 million. more preferably from pieces / mm ^2, and even more preferably from 2,000,000 to 30,000,000 pieces / mm ^2.
Furthermore, the area ratio occupied by the micropores formed by such anodizing treatment (A) is preferably 3 to 50%, and more preferably 5 to 50%.
Here, the area ratio occupied by the micropores is defined by the ratio of the total area of the openings of the micropores to the area of the aluminum surface.

(Film removal treatment (B))
The film removal process (B) is a process for dissolving and removing the anodized film formed on the surface of the aluminum substrate by the anodizing process (A).
After forming the anodized film on the surface of the aluminum substrate by the anodizing treatment (A), the penetration treatment described later may be performed immediately, but after the anodizing treatment (A), the film removal treatment (B) is further performed. In addition, after the re-anodizing treatment (C) described later is performed in this order, it is preferable to perform a penetration treatment described later.

  Since the anodized film becomes more regular as it gets closer to the aluminum substrate, the bottom part of the anodized film remaining on the surface of the aluminum substrate is removed once by this film removal treatment (B). Can be exposed to the surface to obtain regular depressions. Therefore, in the film removal treatment (B), aluminum is not dissolved, but only the anodized film made of alumina (aluminum oxide) is dissolved.

  Alumina solution includes chromium compound, nitric acid, phosphoric acid, zirconium compound, titanium compound, lithium salt, cerium salt, magnesium salt, sodium fluorosilicate, zinc fluoride, manganese compound, molybdenum compound, magnesium compound, barium compound and An aqueous solution containing at least one selected from the group consisting of simple halogens is preferred.

Specific examples of the chromium compound include chromium (III) oxide and anhydrous chromium (VI) acid.
Examples of the zirconium-based compound include zircon ammonium fluoride, zirconium fluoride, and zirconium chloride.
Examples of the titanium compound include titanium oxide and titanium sulfide.
Examples of the lithium salt include lithium fluoride and lithium chloride.
Examples of the cerium salt include cerium fluoride and cerium chloride.
Examples of the magnesium salt include magnesium sulfide.
Examples of the manganese compound include sodium permanganate and calcium permanganate.
Examples of the molybdenum compound include sodium molybdate.
Examples of magnesium compounds include magnesium fluoride pentahydrate.
Examples of barium compounds include barium oxide, barium acetate, barium carbonate, barium chlorate, barium chloride, barium fluoride, barium iodide, barium lactate, barium oxalate, barium perchlorate, barium selenate, selenite. Examples thereof include barium, barium stearate, barium sulfite, barium titanate, barium hydroxide, barium nitrate, and hydrates thereof.
Among the barium compounds, barium oxide, barium acetate, and barium carbonate are preferable, and barium oxide is particularly preferable.
Examples of halogen alone include chlorine, fluorine, and bromine.

Among them, the alumina solution is preferably an aqueous solution containing an acid. Examples of the acid include sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like, and a mixture of two or more acids may be used.
The acid concentration is preferably 0.01 mol / L or more, more preferably 0.05 mol / L or more, and still more preferably 0.1 mol / L or more. There is no particular upper limit, but generally it is preferably 10 mol / L or less, more preferably 5 mol / L or less. An unnecessarily high concentration is not economical, and if it is higher, the aluminum substrate may be dissolved.

  The alumina solution is preferably −10 ° C. or higher, more preferably −5 ° C. or higher, and still more preferably 0 ° C. or higher. In addition, since the starting point of ordering will be destroyed and disturbed if it processes using the boiling alumina solution, it is preferable to use it without boiling.

  The alumina solution dissolves alumina and does not dissolve aluminum. Here, the alumina solution may not dissolve aluminum substantially or may dissolve it slightly.

  The film removal treatment (B) is performed by bringing the aluminum substrate on which the anodized film is formed into contact with the above-described alumina solution. The method of making it contact is not specifically limited, For example, the immersion method and the spray method are mentioned. Of these, the dipping method is preferred.

The dipping method is a treatment in which an aluminum substrate on which an anodized film is formed is dipped in the above-described alumina solution. Stirring during the dipping process is preferable because a uniform process is performed.
The immersion treatment time is preferably 10 minutes or more, more preferably 1 hour or more, and further preferably 3 hours or more and 5 hours or more.

(Re-anodizing treatment (C))
After removing the anodic oxide film by the film removal treatment (B) and forming regular depressions on the surface of the aluminum substrate, the anodic oxidation treatment is performed again, so that the degree of ordering of the micropores is higher. A film can be formed.
The anodizing treatment in the re-anodizing treatment (C) can be performed by a conventionally known method, but is preferably performed under the same conditions as the above-described anodizing treatment (A).
Also, a method of repeatedly turning on and off the current intermittently while keeping the DC voltage constant, and a method of repeatedly turning on and off the current while intermittently changing the DC voltage can be suitably used. According to these methods, fine micropores are generated in the anodic oxide film, which is preferable in that uniformity is improved particularly when sealing treatment is performed by electrodeposition.

When the re-anodizing treatment (C) is performed at a low temperature, the arrangement of micropores becomes regular and the pore diameter becomes uniform.
On the other hand, by performing the re-anodizing treatment (C) at a relatively high temperature, the arrangement of the micropores can be disturbed, and the variation in pore diameter can be made within a predetermined range. Also, the pore diameter variation can be controlled by the processing time.

  In the present invention, the film thickness of the anodized film formed by the re-anodizing treatment (C) is the same as the film thickness of the anodized film formed by the anodizing treatment (A). preferable.

  In the present invention, the average pore diameter and dispersion of the micropores of the anodized film formed by the anodizing treatment (C) are the same as the micropores of the anodized film formed by the anodizing treatment (A). The same as the pore is preferred.

  Furthermore, in the present invention, the average pore density of the micropores formed by the anodizing treatment (C) and the area ratio occupied by the micropores are the same as those of the anodized film formed by the anodizing treatment (A). The same as the micropore is preferable.

  In the self-ordering method I, instead of the above-described anodizing treatment (A) and film removal treatment (B), for example, a physical method, a particle beam method, a block copolymer method, a resist pattern / exposure / etching method, etc. In addition, a recess serving as a starting point for generating micropores by the re-anodizing treatment (C) described above may be formed.

(Physical method)
For example, a method using an imprint method (a transfer method or a press patterning method in which a substrate or a roll having a protrusion is pressed against an aluminum plate to form a recess) can be used. Specifically, a method of forming a depression by pressing a substrate having a plurality of protrusions on the surface thereof against the aluminum surface can be mentioned. For example, a method described in JP-A-10-121292 can be used.
Another example is a method in which polystyrene spheres are arranged in a dense state on the aluminum surface, SiO ₂ is vapor-deposited thereon, then the polystyrene spheres are removed, and the substrate is etched using the vapor-deposited SiO ₂ as a mask to form depressions. It is done.

(Particle beam method)
The particle beam method is a method in which a hollow is formed by irradiating the aluminum surface with a particle beam. The particle beam method has an advantage that the position of the depression can be freely controlled.
Examples of the particle beam include a charged particle beam, a focused ion beam (FIB), and an electron beam.
As the particle beam method, for example, a method described in JP-A-2001-105400 can be used.

(Block copolymer method)
The block copolymer method is a method in which a block copolymer layer is formed on an aluminum surface, a sea-island structure is formed in the block copolymer layer by thermal annealing, and then an island portion is removed to form a depression.
As a block copolymer method, the method described in Unexamined-Japanese-Patent No. 2003-129288 can be used, for example.

(Resist pattern, exposure, etching method)
In the resist pattern / exposure / etching method, the resist on the surface of the aluminum plate is exposed and developed by photolithography or electron beam lithography to form a resist pattern, which is then etched. In this method, a resist is provided and etched to form a recess penetrating to the aluminum surface.

<Self-ordering method II>
(First step: Anodizing treatment (D))
For the anodizing treatment (D), a conventionally known electrolytic solution can be used. When the film formation rate A during energization and the film dissolution rate B during non-energization are set under direct current constant voltage conditions, By performing the treatment using an electrolytic solution in which the parameter R represented by the general formula (i) satisfies 160 ≦ R ≦ 200, preferably 170 ≦ R ≦ 190, particularly preferably 175 ≦ R ≦ 185, The regular arrangement of can be greatly improved.

  R = A [nm / s] ÷ (B [nm / s] × applied voltage [V]) (i)

The average flow rate of the electrolytic solution in the anodizing treatment (D) is preferably 0.5 to 20.0 m / min, similarly to the above-described anodizing treatment (A), and is 1.0 to 15.0 m / min. More preferably, it is 2.0 to 10.0 m / min. By performing anodization treatment (D) at a flow rate in the above range, uniform and high regularity can be obtained.
Moreover, the method of flowing the electrolytic solution under the above-mentioned conditions is not particularly limited as in the case of the above-described anodic oxidation treatment (A). For example, a method using a general stirring device such as a stirrer is used. In particular, it is preferable to use a stirrer that can control the stirring speed with a digital display because the average flow rate can be controlled. Examples of such a stirring apparatus include “Magnetic Stirrer HS-50D (manufactured by AS ONE)” and the like.
The viscosity of the anodizing solution is preferably 0.0001 to 100.0 Pa · s, more preferably 0.0005 to 80.0 Pa · s at 25 ° C. under 1 atm. By performing the anodic oxidation treatment (D) with an electrolytic solution having a viscosity in the above range, uniform and high regularity can be obtained.

Although both acidic and alkaline can be used for the electrolytic solution used in the anodizing treatment (D), an acidic electrolytic solution is preferably used from the viewpoint of enhancing the roundness of the holes.
Specifically, hydrochloric acid, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, glycolic acid, tartaric acid, malic acid, citric acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid, as in the above-described anodizing treatment (A) Of these, sulfuric acid, phosphoric acid, and oxalic acid are particularly preferable. These acids can be used singly or in combination of two or more, adjusted to the desired parameters from the calculation formula of the above general formula (i).

The conditions for the anodizing treatment (D) vary depending on the electrolyte used, and cannot be determined unconditionally. However, as with the above-described anodizing treatment (A), generally, the concentration of the electrolyte is 0.1 to It is preferably 20% by mass, a liquid temperature of −10 to 30 ° C., a current density of 0.01 to 20 A / dm ² , a voltage of 3 to 500 V, an electrolysis time of 0.5 to 30 hours, and an electrolyte concentration of 0.5 to 15 It is more preferable that the mass%, the liquid temperature −5 to 25 ° C., the current density 0.05 to 15 A / dm ² , the voltage 5 to 250 V, the electrolysis time 1 to 25 hours, and the electrolyte concentration 1 to 10 mass%, the liquid More preferably, the temperature is 0 to 20 ° C., the current density is 0.1 to 10 A / dm ² , the voltage is 10 to 200 V, and the electrolysis time is 2 to 20 hours.

  In the present invention, the film thickness of the anodized film formed by such anodizing treatment (D) is preferably the same as the film thickness of the anodized film formed by the anodizing treatment (A). .

  In the present invention, the average pore diameter and dispersion of the micropores formed by the anodizing treatment (D) are the same as the film thickness of the anodized film formed by the anodizing treatment (A). Preferably there is.

  Furthermore, in the present invention, the average pore density of the micropores and the area ratio occupied by the micropores of the anodized film formed by such anodizing treatment (D) are formed by the above-mentioned anodizing treatment (A). The same as the micropore of the anodized film is preferable.

  By this anodizing treatment (D), as shown in FIG. 2A, an anodized film 34 a having micropores 36 a is formed on the surface of the aluminum substrate 32. A barrier layer 38a is present on the aluminum substrate 32 side of the anodized film 34a.

(Second step: oxide film dissolution treatment (E))
The oxide film dissolution treatment (E) is a treatment (pore diameter enlargement treatment) for expanding the pore diameter present in the anodized film formed by the anodization treatment (D).

  The oxide film dissolution treatment (E) is performed by bringing the aluminum substrate after the anodization treatment (D) into contact with an acid aqueous solution or an alkali aqueous solution. The method of making it contact is not specifically limited, For example, the immersion method and the spray method are mentioned. Of these, the dipping method is preferred.

In the oxide film dissolution treatment (E), when an acid aqueous solution is used, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, or a mixture thereof. Especially, the aqueous solution which does not contain chromic acid is preferable at the point which is excellent in safety | security. The concentration of the acid aqueous solution is preferably 1 to 10% by mass. The temperature of the acid aqueous solution is preferably 25 to 60 ° C.
On the other hand, when an alkaline aqueous solution is used in the oxide film dissolution treatment (E), it is preferable to use at least one alkaline aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass. The temperature of the alkaline aqueous solution is preferably 20 to 35 ° C.
Specifically, for example, 50 g / L, 40 ° C. phosphoric acid aqueous solution, 0.5 g / L, 30 ° C. sodium hydroxide aqueous solution or 0.5 g / L, 30 ° C. potassium hydroxide aqueous solution is preferably used. .
The immersion time in the acid aqueous solution or alkali aqueous solution is preferably 8 to 120 minutes, more preferably 10 to 90 minutes, and still more preferably 15 to 60 minutes.

  Further, in the oxide film dissolution treatment (E), the amount of enlargement of the pore diameter varies depending on the conditions of the anodization treatment (D), but the enlargement ratio before and after the treatment is preferably 1.05 times to 100 times, and 1.1 times to 75 times is more preferable, and 1.2 times to 50 times is particularly preferable.

  By this oxide film dissolution treatment (E), as shown in FIG. 2 (B), the surface of the anodized film 34a and the inside of the micropores 36a (barrier layer 38a and porous layer) shown in FIG. 2 (A). The aluminum member having the anodic oxide film 34b having the micropores 36b on the aluminum substrate 32 is obtained. As in FIG. 2A, a barrier layer 38b is present on the aluminum substrate 32 side of the anodized film 34b.

(Third step: Anodizing treatment (D))
In the self-ordering method II, the anodic oxidation treatment (D) is preferably performed again after the oxide film dissolution treatment (E).

  By anodizing treatment (D) again, as shown in FIG. 2C, the oxidation reaction of the aluminum substrate 32 shown in FIG. 2B proceeds, and on the aluminum substrate 32, more than the micropores 36b. An aluminum member having an anodic oxide film 34c having deep micropores 36c is obtained. As in FIG. 2A, a barrier layer 38c is present on the aluminum substrate 32 side of the anodized film 34c.

(Fourth step: oxide film dissolution treatment (E))
Further, in the self-ordering method II, after the anodic oxidation treatment (D), the oxide film dissolution treatment (E) and the anodic oxidation treatment (D) are performed in this order, the oxide film dissolution treatment (E) is further performed. It is preferable to apply.

By this treatment, since the treatment liquid enters the micropores, all the anodized film formed in the anodizing treatment (D) performed in the third step is dissolved, and the anodizing treatment performed in the third step The pore diameter of the micropore formed in (D) can be increased.
That is, by the oxide film dissolution treatment (E) again, as shown in FIG. 2 (D) and FIG. 3, the micropores 36c on the surface side from the inflection point of the anodic oxide film 34c shown in FIG. 2 (C). Thus, an aluminum member having an anodic oxide film 34d having straight tubular micropores 36d on the aluminum substrate 32 is obtained. As in FIG. 2A, a barrier layer 38d is present on the aluminum substrate 32 side of the anodized film 34d.

  Here, the amount of expansion of the pore diameter of the micropore varies depending on the processing conditions of the anodizing treatment (D) performed in the third step, but the expansion ratio before and after the treatment is preferably 1.05 times to 100 times. 1 to 75 times is more preferable, and 1.2 to 50 times is particularly preferable.

In the self-ordering method II, the cycle of the above-described anodizing treatment (D) and oxide film dissolution treatment (E) is performed one or more times. The greater the number of repetitions, the higher the regularity of the pore arrangement described above.
In addition, by completely dissolving the anodized film formed by the last anodizing process (D) by the oxide film dissolving process (E), the roundness of the micropores viewed from the surface of the film is dramatically improved. The above cycle is preferably repeated twice or more, more preferably 3 times or more, and even more preferably 4 times or more.
In addition, when the above cycle is repeated twice or more, the conditions of each oxide film dissolution treatment and anodization treatment may be the same or different, respectively, and the last treatment is anodization treatment. You can finish it.

  In the present invention, the thickness of the anodized film formed by such a self-ordering method II is preferably the same as the micropore of the anodized film formed by the anodizing treatment (A).

  In the present invention, the micropores and dispersion of the anodized film formed by such a self-ordering method II are the same as the film thickness of the anodized film formed by the anodizing process (A). Is preferred.

  Furthermore, in the present invention, the average pore density of the micropores formed by the self-ordering method II and the area ratio occupied by the micropores are determined by the micropores of the anodized film formed by the anodizing treatment (A). The same as the pore is preferred.

<Constant voltage processing>
The constant voltage treatment is a treatment method in which an anodized film is formed at a low speed over a long time (for example, several hours to several tens of hours). In this processing method, since the pore diameter depends on the voltage, it is essential to control the voltage to be constant from the viewpoint of preventing branching of the micropores.

The average flow rate of the electrolytic solution in the anodizing treatment is preferably 0.5 to 20.0 m / min, more preferably 1.0 to 15.0 m / min, and 2.0 to 10.0 m / min. More preferably, it is min. By performing anodizing treatment at a flow rate in the above range, uniform and high regularity can be obtained.
Moreover, the method of flowing the electrolytic solution under the above-mentioned conditions is not particularly limited, but, for example, a method using a general stirring device such as a stirrer is used. In particular, it is preferable to use a stirrer that can control the stirring speed by digital display because the average flow velocity can be controlled. Examples of such a stirring apparatus include “Magnetic Stirrer HS-50D (manufactured by AS ONE)” and the like.

For the anodizing treatment, for example, a method in which an aluminum substrate is used as an anode in a solution having an acid concentration of 1 to 10% by mass can be used.
The solution used for the anodizing treatment is preferably an acid solution, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid, glycolic acid, tartaric acid, malic acid, citric acid. Of these, sulfuric acid, phosphoric acid, and oxalic acid are particularly preferable. These acids can be used alone or in combination of two or more.

The conditions for anodizing treatment vary depending on the electrolyte used, and therefore cannot be determined unconditionally. In general, however, the electrolyte concentration is 0.1 to 20% by mass, the solution temperature is -10 to 30 ° C., and the current density. 0.01 to 20 A / dm ² , voltage 3 to 300 V, electrolysis time 0.5 to 50 hours are preferable, electrolyte concentration 0.5 to 15% by mass, liquid temperature −5 to 25 ° C., current density 0 0.05 to 15 A / dm ² , voltage 5 to 250 V, electrolysis time 1 to 25 hours are more preferable, electrolyte concentration 1 to 10% by mass, solution temperature 0 to 20 ° C., current density 0.1 to 10 A / dm ² , voltage 10-2
More preferably, it is 00V and electrolysis time is 2 to 20 hours.

  The treatment time for the anodizing treatment is preferably 0.5 minutes to 16 hours, more preferably 1 minute to 12 hours, and further preferably 2 minutes to 8 hours.

  In the present invention, the film thickness of the anodized film formed by such constant voltage treatment is preferably the same as the film thickness of the anodized film formed by the anodizing process (A).

  In the present invention, the average pore diameter and dispersion of the micropores of the anodized film formed by such constant voltage treatment are the same as the film thickness of the anodized film formed by the anodizing process (A). Is preferred.

  Furthermore, in the present invention, the average pore density of the micropores formed by such constant voltage treatment and the area ratio occupied by the micropores are the same as the micropores of the anodized film formed by the anodizing treatment (A). The same is preferred.

<Constant current processing>
The constant current treatment is preferably performed at the end of the anodizing treatment. As a result, the thickness of the anodized film can be increased and the axial length of the micropores can be increased without reducing the order of the pore arrangement.

In the anodic oxidation treatment by constant current treatment, the electrolysis time is preferably 5 minutes to 30 hours, and more preferably 30 minutes to 5 hours.
Further, the fluctuation range of the constant current is preferably ± 10 to 1 A / m ² .

In the anodic oxidation treatment by the constant current treatment, the electrolytic solution, the electrolytic solution concentration, the temperature condition, etc. may be the same as or different from the above-described anodizing treatment (A).
In particular, the current density is preferably 0~10000A / m ^2, more preferably ^{0~1000A / m 2, 0~400A / m} 2 is more preferable.

[Penetration processing]
The penetration treatment is a treatment for obtaining the anodized film having the through holes by penetrating the holes by the micropores generated by the anodization after the anodization treatment.
Specifically, as the penetration treatment, for example, after the anodizing treatment, an aluminum substrate (portion represented by reference numeral 32 in FIG. 2D) is dissolved and the bottom portion of the anodized film (see FIG. 2 (D), a method of removing a portion 38d); a method of cutting an aluminum substrate and an anodized film in the vicinity of the aluminum substrate after the anodizing treatment step; and the like.
Next, the former method which is a preferred embodiment will be described in detail.

<Dissolution of aluminum substrate>
For the dissolution of the aluminum substrate after the anodizing treatment step, a treatment solution in which the anodized film (alumina) is difficult to dissolve and aluminum is easily dissolved is used.
That is, the aluminum dissolution rate is 1 μm / min or more, preferably 3 μm / min or more, more preferably 5 μm / min or more, and the anodic oxide film dissolution rate is 0.1 nm / min or less, preferably 0.05 nm / min or less, more preferably Uses a treatment liquid having a condition of 0.01 nm / min or less.
Specifically, a treatment liquid containing at least one metal compound having a lower ionization tendency than aluminum and having a pH of 4 or less and 8 or more, preferably 3 or less and 9 or more, more preferably 2 or less and 10 or more is used. Immerse treatment.

Such treatment liquid is based on an acid or alkaline aqueous solution, for example, manganese, zinc, chromium, iron, cadmium, cobalt, nickel, tin, lead, antimony, bismuth, copper, mercury, silver, palladium, platinum, A gold compound (for example, chloroplatinic acid), a fluoride thereof, a chloride thereof, or the like is preferably used.
Among them, an acid aqueous solution base is preferable, and it is preferable to blend a chloride.
In particular, a treatment liquid (hydrochloric acid / mercury chloride) in which mercury chloride is blended with an aqueous hydrochloric acid solution and a treatment liquid (hydrochloric acid / copper chloride) in which copper chloride is blended with an aqueous hydrochloric acid solution are preferable from the viewpoint of treatment latitude.
The composition of such a treatment liquid is not particularly limited, and for example, a bromine / methanol mixture, a bromine / ethanol mixture, aqua regia and the like can be used.

  Moreover, 0.01-10 mol / L is preferable and, as for the acid or alkali concentration of such a processing liquid, 0.05-5 mol / L is more preferable.

  Furthermore, the processing temperature using such a processing liquid is preferably −10 ° C. to 80 ° C., more preferably 0 ° C. to 60 ° C.

  In the present invention, the aluminum substrate is dissolved by bringing the aluminum substrate after the anodizing treatment into contact with the treatment liquid described above. The method of making it contact is not specifically limited, For example, the immersion method and the spray method are mentioned. Of these, the dipping method is preferred. The contact time at this time is preferably 10 seconds to 5 hours, and more preferably 1 minute to 3 hours.

  By dissolving the aluminum substrate, a structure in which the aluminum substrate 32 shown in FIG. 2D is eliminated, that is, a structure made of the anodized film 34 having the micropores 36 is obtained (see FIG. 4). .

<Removal of the bottom of the anodized film>
The bottom part of the anodized film after the aluminum substrate is dissolved is removed by dipping in an acid aqueous solution or an alkali aqueous solution. By removing the bottom anodic oxide film, the pores by the micropores penetrate.

  The bottom of the anodized film is removed by pre-soaking in a pH buffer solution and filling the hole with the pH buffer solution from the opening side of the micropore, and then on the opposite side of the opening, that is, on the bottom of the anodized film. It is preferably carried out by a method of contacting with an acid aqueous solution or an alkali aqueous solution.

In the case of using an acid aqueous solution, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid or a mixture thereof. The concentration of the acid aqueous solution is preferably 1 to 10% by mass. The temperature of the acid aqueous solution is preferably 25 to 40 ° C.
On the other hand, when using an alkaline aqueous solution, it is preferable to use an aqueous solution of at least one alkali selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass. The temperature of the alkaline aqueous solution is preferably 20 to 35 ° C.

  Specifically, for example, a 50 g / L, 40 ° C. phosphoric acid aqueous solution, a 0.5 g / L, 30 ° C. sodium hydroxide aqueous solution, or a 0.5 g / L, 30 ° C. potassium hydroxide aqueous solution is suitably used. It is done.

The immersion time in the acid aqueous solution or alkali aqueous solution is preferably 8 to 120 minutes, more preferably 10 to 90 minutes, and still more preferably 15 to 60 minutes.
Moreover, when immersing in a pH buffer solution beforehand, the buffer solution corresponding to the acid / alkali mentioned above is used appropriately.

  By removing the bottom of the anodized film, a structure in which the aluminum substrate 32 and the barrier layer 38d shown in FIG. 2D are eliminated, that is, a structure composed of the anodized film 34 having the through holes 37 is obtained. Is obtained (see FIG. 5).

  On the other hand, as a method for cutting the latter aluminum substrate and the anodic oxide film in the vicinity of the aluminum substrate, an aluminum substrate (portion represented by reference numeral 32 in FIG. 2D) and the bottom of the anodic oxide film (FIG. 2D). ) Is preferably exemplified by a method in which the portion represented by the reference numeral 38d) is physically removed using a cutting process using a laser or the like or various polishing processes. Also by these methods, a structure in which the aluminum substrate 32 and the barrier layer 38d shown in FIG. 2D are eliminated, that is, a structure including the anodic oxide film 34 having the through holes 37 is obtained (FIG. 5). reference).

[Hydrate]
The hydrate is a hydrate of the valve metal formed in at least a part of the through-holes in the anodic oxide film.
Here, the valve metal is the same as that described for the valve metal subjected to the formation of the anodized film, that is, the above-described anodizing treatment.
In the present invention, the valve metal is the same type of metal as the valve metal subjected to the above-described anodizing treatment, that is, when anodized film is formed by anodizing aluminum (substrate), for example, aluminum or titanium. In the case where the anodic oxide film is formed by anodizing the (substrate), titanium is preferred.

For example, in the case of aluminum, the hydrate may be in a crystalline state or an amorphous state, and examples of the crystalline form include gibbsite, boehmite, bayerite, and the like. Among these, an amorphous state and boehmite are preferable. Specific examples include Al (OH) ₃ and AlOOH.
In addition, it is known that aluminum hydrates can be transformed into oxides of different crystal forms by firing treatment. For example, boehmite transforms to γ-alumina when calcined at 480 to 760 ° C., and 760 to 920. When it is fired at 0 ° C., it changes to Δ-alumina, when it is fired at 920 to 1020 ° C., it changes to θ-alumina, and when it is fired at 1020 ° C. or more, it changes to α-alumina. Further, the amorphous state and bayerite transition to η-alumina at 240 to 780 ° C., and transition to α-alumina at 1000 ° C. or higher.
Thus, aluminum hydroxide is particularly preferable because it can be transferred to an oxide having high chemical resistance by the baking treatment.
On the other hand, titanium hydroxide is also preferable because it can be transformed into an oxide such as a rutile type or anatase type, which has a strong chemical corrosion resistance, by firing treatment.

  Further, as described above, the hydrate may be formed in a part of the through hole as shown in FIGS. 1A and 1B. As shown, it may be formed over the entire through hole.

By forming such a hydrate, the fuel cell electrolyte membrane of the present invention has good durability against methanol and proton selectivity even when used at high temperatures.
Although this is not clear in detail, the durability of the anodic oxide film itself to methanol is extremely high, and the formation of a hydrate clogs a part of the through-hole so that only the proton does not pass through the methanol. This is thought to be due to the formation of fine pores with a pore diameter of about 0.1 to 1 nm.

  Although the formation method of the said hydrate is not specifically limited, It is preferable to perform the hydration process shown below with respect to the said anodic oxide film which has the said through-hole.

[Hydration treatment]
The hydration treatment is a treatment for generating a hydrate inside the through hole of the anodic oxide film, and a treatment performed by supplying an alkaline aqueous solution adjusted to a predetermined pH inside the through hole. .
The pH of the alkaline aqueous solution is preferably 9 to 13, more preferably 10 to 11.5, and still more preferably 11 to 12.
The pH of the alkaline aqueous solution can be adjusted with degassed pure, ammonia, or a highly volatile chemical solution.
Specific examples of the chemical solution include an aqueous solution of an organic acid such as oxalic acid, malonic acid, tartaric acid, and succinic acid; and an aqueous solution of an inorganic acid such as phosphoric acid, hydrochloric acid, sulfuric acid, and chromic acid. It is done.

Specific examples of the alkaline aqueous solution include an aqueous solution containing at least one compound selected from the group consisting of ammonia, triethanolamine and sodium silicate.
Among these, an aqueous ammonia solution is preferable because the amount of hydrate to be generated, the position in the through hole, and the particle size of the hydrate can be easily controlled.

  The method for supplying the alkaline aqueous solution is not particularly limited, but the alkaline aqueous solution may be applied to the entire surface of the anodic oxide film having the through holes. A method of immersing in an alkaline aqueous solution is preferable.

In the present invention, as shown in FIGS. 1 (A) and (B), when the hydrate is formed in a part of the through-hole, the hydration treatment temperature, that is, the immersion treatment is used. The temperature of the alkaline aqueous solution is preferably 30 to 100 ° C., preferably 40 to 98 ° C., because the selective sealing (occlusion) state of the opening of the through hole by the hydrate is good. It is more preferable that it is 50-95 degreeC.
Further, the treatment time of the hydration treatment, that is, in the case of immersion treatment, the immersion time in the alkaline aqueous solution is 10 seconds to 60 minutes from the viewpoint of workability, stability of the alkaline aqueous solution, and the like. Preferably, it is 20 seconds to 45 minutes, more preferably 30 seconds to 30 minutes.
When only one side of the anodic oxide film having the through hole is immersed in the alkaline aqueous solution, a hydrate is formed only on one side of the through hole (see FIG. 1A), and the through hole is provided. When the entire anodic oxide film is immersed in the alkaline aqueous solution, hydrates are formed on both sides of the through hole.

On the other hand, in the present invention, as shown in FIG. 1 (C), when the hydrate is formed over the entire through-hole, the treatment temperature of the hydration treatment is the same as the entire through-hole due to the hydrate. It is preferably 1 to 40 ° C., more preferably 3 to 35 ° C., and still more preferably 5 to 30 ° C. for the reason that the sealed (closed) state is good.
Further, the treatment time of the hydration treatment, that is, in the case of immersion treatment, the immersion time in the alkaline aqueous solution is 10 for the reason that the sealed (closed) state of the entire through-hole by the hydrate is good. It is preferably from minutes to 24 hours, more preferably from 30 minutes to 18 hours, and even more preferably from 45 minutes to 3 hours.
In addition, when making it form in the whole said through-hole, it is preferable to immerse the whole said anodic oxide film which has the said through-hole in the said alkaline aqueous solution, and to form a hydrate from the both sides of the said through-hole.

  The fuel cell electrolyte membrane of the present invention having the above-described anodized film and hydrate can be subjected to the following treatments as necessary.

(Through hole modification treatment)
In the present invention, when the hydrate is formed in a part of the through hole (see, for example, FIG. 1 (A) or (B)), the proton selectivity of the fuel cell electrolyte membrane of the present invention is further improved. From the viewpoint of improvement, it is preferable to modify the inner wall of the through hole in which the hydrate is not formed with a proton conductive functional group (for example, a hydroxyl group).
Here, for the modification with the proton conductive functional group, the method described in Patent Document 2 can be used.

[Baking treatment]
In the present invention, from the viewpoint of further improving the proton selectivity of the fuel cell electrolyte membrane of the present invention, the anodic oxide film having the through-hole formed with the hydrate, ie, the fuel cell of the present invention. Preferably, the electrolyte membrane is fired to oxidize the hydrate.
Here, the firing temperature is preferably 300 to 600 ° C, more preferably 400 to 580 ° C, and still more preferably 500 to 580 ° C. When the temperature range is within this range, for example, when an aluminum hydrate is baked, crystal change to alumina becomes possible, and micropores with a pore diameter of about 0.1 to 1 nm that allow only protons to pass through without passing through methanol. It becomes easy to be formed.
In addition, the firing atmosphere is preferably an atmosphere containing at least oxygen, and more preferably in the air.
The firing is preferably performed at atmospheric pressure from the viewpoint of convenience.

[Hydrophilic treatment]
In the present invention, from the viewpoint of further improving the proton selectivity of the fuel cell electrolyte membrane of the present invention, when the above baking treatment is performed, it is preferable to perform the hydrophilic treatment after the above baking treatment.
Specific examples of the hydrophilic treatment method include a method of immersing in an aqueous solution of an alkali metal silicate; a method of forming a hydrophilic undercoat layer by applying a hydrophilic vinyl polymer or a hydrophilic compound And the like.

  Here, the hydrophilization treatment using an aqueous solution of alkali metal silicate is performed according to the method and procedure described in US Pat. No. 2,714,066 and US Pat. No. 3,181,461. It can be carried out.

  Specific examples of the alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate.

  The aqueous solution of the alkali metal silicate may further contain sodium hydroxide, potassium hydroxide, lithium hydroxide and the like.

Furthermore, the aqueous solution of the alkali metal silicate may further contain an alkaline earth metal salt or a Group 4 (Group IVA) metal salt.
Here, specific examples of the alkaline earth metal salt include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate; sulfates; hydrochlorides; phosphates; acetates; Borate; and the like.
Specific examples of the Group 4 (Group IVA) metal salt include, for example, titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, and chloride oxidation. Zirconium, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride and the like can be mentioned.
These alkaline earth metal salts and Group 4 (Group IVA) metal salts may be used alone or in combination of two or more.

In the hydrophilization treatment, when an aqueous solution of the alkali metal silicate is used, the concentration of the alkali metal silicate is preferably 0.1 to 10% by mass, and 0.4 to 8% by mass. Is more preferable, and it is still more preferable that it is 0.8-4 mass%.
The temperature of the alkali metal silicate aqueous solution is preferably 1 to 70 ° C, more preferably 2 to 50 ° C, and further preferably 3 to 35 ° C.
Further, the treatment time in the case of using the alkali metal silicate aqueous solution is preferably 5 seconds to 90 minutes, preferably 8 seconds to 60 minutes, and preferably 12 seconds to 30 minutes. Further preferred.

[Polymer filling treatment]
In the present invention, when the hydrate is formed in a part of the through hole (see, for example, FIG. 1 (A) or (B)), the proton selectivity of the fuel cell electrolyte membrane of the present invention is further improved. From the viewpoint of improvement, it is preferable to fill a hydrophilic polymer having proton conductivity into the through hole in a portion where the hydrate is not formed.

The hydrophilic polymer preferably forms fine pores having a pore diameter of about 0.1 to 1 nm that allows only protons to pass through without passing through methanol.
The hydrophilic polymer is preferably filled with a monomer and a crosslinking agent described later and then polymerized by heat, light or the like.

  Examples of the monomer include a proton acidic group-containing monomer having a functional group polymerizable in one molecule and a protonic acid or a functional group that can be easily converted to a protonic acid by an operation such as neutralization or hydrolysis. Is mentioned.

  Specific examples of the proton acidic group-containing monomer include 2- (meth) acrylamide-2-methylpropanesulfonic acid, styrenesulfonic acid, (meth) allylsulfonic acid, vinylsulfonic acid, isoprenesulfonic acid, ( Examples thereof include (meth) acrylic acid, maleic acid, crotonic acid, sulfonic acid group-containing vinyl compounds, phosphoric acid group-containing vinyl compounds, acidic phosphoric acid group-containing (meth) acrylates, salts, anhydrides and esters thereof.

Here, when the acid residue of the protonic acid group-containing monomer is a derivative such as a salt, an anhydride, or an ester, proton conductivity can be imparted by forming a protonic acid type after polymerization.
Further, “(meth) acryl” means “acryl and / or methacryl”, “(meth) allyl” means “allyl and / or methallyl”, and “(meth) acrylate” means “acrylate and / or methacrylate”. Is.

  Of these, a sulfonic acid group-containing vinyl compound or a phosphoric acid group-containing vinyl compound is preferable because of its excellent proton conductivity, and 2- (meth) acrylamide-2-methylpropanesulfonic acid has a high polymerizability, so that preferable.

  On the other hand, the crosslinking agent has two or more polymerizable functional groups in one molecule, and forms a crosslinking point in the polymer by blending and polymerizing with the monomer.

  Specific examples of the crosslinking agent include N, N-methylenebis (meth) acrylamide, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane diallyl ether, and pentaerythritol triallyl ether. , Divinylbenzene, bisphenol di (meth) acrylate, isocyanuric acid di (meth) acrylate, tetraallyloxyethane, triallylamine, diallyloxyacetate and the like.

In addition, as other crosslinking agents, bifunctional or higher functional epoxy compounds can be used although they are inferior in that the polymerization reaction rate is low.
When an epoxy compound is used, it may be cross-linked by reacting with an acid such as a carboxyl group in the polymer, or a copolymerizable compound having a hydroxyl group or the like as a third component may be added to the monomer.

  These cross-linking agents can be used alone or in combination of two or more as required.

  In the present invention, the amount of the crosslinking agent used is such that the ratio of the number of moles of the monomer to the number of moles of the crosslinking agent and the average number of functional groups per molecule of the crosslinking agent is 50: 2 to 50: 50 is preferable, and 50: 4 to 50:40 is more preferable.

In the present invention, in addition to the above-described monomer and crosslinking agent, other copolymer components can be blended as necessary from the viewpoint of adjusting the swelling property of the polymer.
Other copolymerization components are not particularly limited as long as they can be copolymerized with the above-described monomers and crosslinking agents. For example, (meth) acrylic acid esters, (meth) acrylamides, maleimides, styrenes, organic Examples include vinyl acids and allyl compounds.

Furthermore, in the present invention, a known aqueous radical polymerization technique can be used as a method for polymerizing the above-described monomers.
Specific examples include redox-initiated polymerization, heat-initiated polymerization, electron beam-initiated polymerization, and photoinitiated polymerization such as ultraviolet rays.
Specific examples of the radical polymerization initiator for redox-initiated polymerization and thermal-initiated polymerization include azo compounds such as 2,2′-azobis (2-amidinopropane) dihydrochloride; ammonium persulfate, potassium persulfate, Peroxides such as sodium sulfate, hydrogen peroxide, benzoyl peroxide, cumene hydroperoxide, di-t-butyl peroxide; the above peroxides and sulfites, bisulfites, thiosulfates, formamidine sulfinic acids In combination with a reducing agent such as ascorbic acid (redox initiator); azo radical polymerization initiators such as 2,2′-azobis- (2-amidinopropane) dihydrochloride and azobiscyanovaleric acid; It is done.
These radical polymerization initiators may be used alone or in combination of two or more.
Among these, peroxide-based radical polymerization initiators can generate radicals by extracting hydrogen from carbon-hydrogen bonds, and therefore form a chemical bond between the substrate surface and the filled polymer. Is preferable.

On the other hand, among the above polymerization initiation means, photoinitiated polymerization with ultraviolet rays is preferred because the polymerization reaction is easily controlled and a desired electrolyte membrane can be obtained with a relatively simple process and high productivity.
Further, when photoinitiating polymerization with ultraviolet rays, it is preferable to previously dissolve or disperse a radical photopolymerization initiator in a monomer solution or a monomer dispersion.

Specific examples of the radical photopolymerization initiator include benzoin, benzyl, acetophenone, benzophenone, quinone, thioxanthone, thioacridone, and derivatives thereof that are generally used for ultraviolet polymerization.
Among these, aromatic ketone radical polymerization initiators such as benzophenone, thioxanthone, quinone, and thioacridone can generate radicals by extracting hydrogen from carbon-hydrogen bonds. It is preferable because a chemical bond can be formed between them.

  The amount of the photopolymerization initiator used is preferably 0.001 to 1% by mass, more preferably 0.001 to 0.5% by mass, and 0.01 to 0.5% by mass with respect to the total mass of the monomers described above. % Is more preferable.

In the present invention, when the above-described through holes in the portion where the hydrate is not formed are filled with the above-described monomers, a solution in which the above-described monomers, crosslinking agents, polymerization initiators, etc. are mixed to form a liquid Alternatively, it is preferable to use a dispersion.
The concentration of the above-mentioned monomer in this solution or dispersion is preferably 10 to 90%, more preferably 20 to 70%.
For the purpose of facilitating the impregnation operation, it is preferable to perform ultrasonic irradiation during the above-described hydrophilization treatment, addition of a surfactant to the solution or dispersion, and filling (impregnation).
Filling is preferably performed under pressure or under reduced pressure because no filling defect occurs. In addition, it is preferable that there is no defect such as an unfilled portion at the time of filling from the viewpoint of further improving the proton selectivity of the fuel cell electrolyte membrane of the present invention.

  The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.

Example 1
1. Preparation of electrolyte membrane (1) Electropolishing treatment After cutting a high-purity aluminum substrate (manufactured by Sumitomo Light Metal Co., Ltd., purity 99.99 mass%, thickness 0.4 mm) so that it can be anodized in an area of 10 cm square, Using the electrolytic polishing liquid having the composition, the electrolytic polishing treatment was performed under the conditions of a voltage of 10 V, a liquid temperature of 65 ° C., and a liquid flow rate of 3.0 m / min.
The cathode was a carbon electrode, and GP0110-30R (manufactured by Takasago Seisakusho) was used as the power source. The flow rate of the electrolytic solution was measured using a vortex flow monitor FLM22-10PCW (manufactured by AS ONE).

<Electrolytic polishing liquid composition>
・ 85 mass% phosphoric acid (Wako Pure Chemical Industries, Ltd.) 1320mL
・ Pure water 80mL
・ 600 mL of sulfuric acid

(2) Degreasing treatment The sample after the polishing treatment obtained above is immersed in a treatment solution of 1.75 mol / L sodium hydroxide and 0.16 mol / L sodium nitrate for 30 to 90 seconds at 60 ° C. Degreasing treatment was performed.

(3) Anodizing treatment First, to the sample after degreasing treatment obtained above, an electrolytic solution of 5.00 mol / L malonic acid with a voltage of 130.0 V, a liquid temperature of 3 ° C., and a liquid flow rate of 5.0 m / min. Anodizing treatment was performed for 7.5 minutes under the conditions. The voltage was set to a constant voltage setting of 130.0 V (± 0.1 V) using GPO-250-30R (manufactured by Takasago Seisakusho).
Next, the sample after the anodizing treatment was subjected to a film removal treatment of dipping in a 0.52 mol / L phosphoric acid aqueous solution (liquid temperature: 40 ° C.) for 42.5 minutes.
These treatments were repeated 4 times in this order.

Next, the sample after the fourth film removal treatment was treated with an electrolyte solution of 5.00 mol / L malonic acid for 7.5 minutes under conditions of a voltage of 130.0 V, a liquid temperature of 3 ° C., and a liquid flow rate of 5.0 m / min. Oxidation treatment was performed. The voltage was set to a constant voltage setting of 130.0 V (± 0.1 V) using GPO-250-30R (manufactured by Takasago Seisakusho).
Next, the anodized sample obtained above was anodized with an electrolyte solution of 5.00 mol / L malonic acid for 90 minutes under the conditions of a current density of 120 A / m ² and a liquid temperature of 3 ° C. The current was measured by using a current transformer and a voltmeter, and the current flowing through the conductor was measured and controlled to 120 A / m ² (± 10 A / m ² ).

(4) Penetration treatment Next, an aluminum substrate was dissolved by immersion for 20 minutes at a liquid temperature of 10 ° C. using a treatment liquid in which 0.1 mol / L copper chloride was blended with 20% hydrochloric acid aqueous solution.
Thereafter, the entire sample obtained was immersed in a 5% KCl buffer solution for 10 minutes, and then only the bottom portion (barrier layer side) of the anodized film was immersed in an aqueous 0.1N-KOH solution at 30 ° C. for 30 minutes. The bottom part of the anodic oxide film was removed, and the structure which consists of an anodic oxide film which has the micropore (through-hole) which expanded the pore diameter was produced.
The surface photograph and cross-sectional photograph (magnification 20000 times) of the obtained structure after the penetration treatment were photographed with FE-SEM and confirmed to have the following shape.
-Structure thickness: 50 μm
-Depth of through hole: 50 μm
・ Average hole diameter of through-holes: 80 nm
-Period of through holes (distance between centers): 280 nm
-Ordering degree of through holes: 78%

Here, the period of the through hole refers to the center-to-center distance (pitch) of the through hole, and is an average value measured at 50 points.
Further, the degree of ordering of the through holes is a value obtained by measuring the degree of ordering defined by the following formula (ii).

Ordering degree (%) = B / A × 100 (ii)
In the above formula (ii), A represents the total number of through holes in the measurement range. B is centered on the center of gravity of one through-hole, and when a circle with the shortest radius inscribed in the edge of the other through-hole is drawn, the center of gravity of the through-holes other than the one through-hole is set inside the circle. The number in the measurement range of the one through-hole to be included is represented.

Here, FIG. 6 is an explanatory diagram of a method for calculating the degree of ordering of the through holes. The above formula (ii) will be described more specifically with reference to FIG.
The through-hole 101 shown in FIG. 6A draws a circle 103 (inscribed in the through-hole 102) having the shortest radius inscribed in the edge of another through-hole with the center of gravity of the through-hole 101 as the center. In such a case, the center of gravity of the through holes other than the through hole 101 is included in the circle 3. Therefore, the through hole 101 is included in B.
The through-hole 104 shown in FIG. 6 (B) draws a circle 106 (inscribed in the through-hole 105) having the shortest radius that is centered on the center of gravity of the through-hole 104 and inscribed in the edge of the other through-hole. In this case, the center of the through hole other than the through hole 104 is included in the circle 106. Therefore, the through hole 104 is not included in B.
Further, the through hole 107 shown in FIG. 6B is centered on the center of gravity of the through hole 107 and has the shortest radius 109 inscribed in the edge of the other through hole (inscribed in the through hole 108). Is drawn, the center of the through hole other than the through hole 107 is included in the circle 109. Therefore, the through hole 107 is not included in B.

(5) Hydration treatment One side of the structure after penetration treatment obtained above was brought into contact with ammonia water (liquid temperature 80 ° C.) adjusted to pH 11.4.
After contacting for 30 minutes, a surface photograph and a cross-sectional photograph (magnification 100000 times) were taken with an FE-SEM. As a result, an electrolyte membrane in which one side of the through hole was sealed with granular hydrate was produced. It could be confirmed.

(6) Firing The electrolyte membrane after the hydration treatment was fired, and the hydrate formed in the through holes was modified to alumina.
Firing was performed at a temperature increase rate of 10 ° C./10 min, then maintained at 550 ° C. for 3 hours, and a temperature decrease rate of 2 ° C./10 min.

  The electrolyte membrane obtained after firing was evaluated for methanol permeability and proton conductivity by the following methods. The results are shown in Table 1 below.

<Methanol permeability>
The methanol permeation performance test was performed by pervaporation experiments at 120 ° C. The feed liquid was methanol / water (mass ratio) = 1/9, and the permeation side was depressurized until the permeation flow rate became steady.
Specifically, the obtained electrolyte membrane was sandwiched between stainless steel cells, and the above supply solution was placed on the upper surface of the membrane and stirred. Here, the supply liquid was supplied by inserting a heater and a resistance temperature detector in the liquid and maintaining the temperature at 120 ° C.
Next, the lower surface of the membrane, that is, the permeate side was decompressed, and methanol and water vapor that permeated the membrane were collected in a cold trap.
The collected vapor, that is, water vapor that has become solid in the cold trap is heated and dissolved, and then taken out as a liquid. The total permeation coefficient is measured from its mass, and the permeated vapor composition is measured by gas chromatographic analysis. did.
The data for several hours until the membrane permeation performance was stabilized was ignored, and the value at which the membrane permeation performance was constant with respect to time was evaluated as the steady-state permeability.

<Proton conductivity>
After the obtained electrolyte membrane was swollen in water (temperature: 25 ° C.), a sample for proton conductivity measurement sandwiched between two platinum foil electrodes was prepared, and impedance measurement was performed using HP4192A (manufactured by Hewlett-Packard Company). Went.

(Example 2)
The process up to the firing treatment was performed in the same manner as in Example 1 to produce an electrolyte membrane, and a hydrophilic polymer having proton conductivity was filled in the through hole to produce an electrolyte membrane.
Here, the filling of the hydrophilic polymer was performed as follows.
First, a mixture of 99 mol% 2-acrylamido-2-methylpropanesulfonic acid and 1 mol% methylenebisacrylamide as a crosslinking agent was diluted with water to 50 mass%.
Next, 1 mol% of a water-soluble azo initiator (V-50, manufactured by Wako Pure Chemical Industries, Ltd.) was added to 100 mol% of the total amount of 2-acrylamido-2-methylpropanesulfonic acid and methylenebisacrylamide.
This mixed solution was dropped on the electrolyte membrane surface in a vacuum chamber, and then irradiated with visible light for 6 minutes. Then, it heated in 50 degreeC oven for 18 hours.
Next, excess polymer on the surface of the electrolyte membrane is removed, ion exchange is performed using a large excess of 1N hydrochloric acid, and then thoroughly washed with distilled water, and dried in an oven at 50 ° C., so that the hydrophilic polymer is placed in the through holes. A filled electrolyte membrane was obtained.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. The results are shown in Table 1 below.

(Example 3)
The process up to the firing treatment was performed in the same manner as in Example 1 to produce an electrolyte membrane, and then a hydrophilic treatment was performed to produce an electrolyte membrane.
Here, the hydrophilization treatment was performed by immersing the electrolyte membrane in a silicate treatment solution (No. 3 sodium silicate diluted water, Si concentration: 2% by mass, manufactured by Nippon Chemical Industry Co., Ltd.) at a liquid temperature of 35 ° C. for 1 minute.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. The results are shown in Table 1 below.

Example 4
An electrolyte membrane was produced in the same manner as in Example 3, and a hydrophilic polymer having proton conductivity was filled in the through hole to produce an electrolyte membrane.
Here, the filling of the hydrophilic polymer was performed as follows.
First, a mixture of 99 mol% 2-acrylamido-2-methylpropanesulfonic acid and 1 mol% methylenebisacrylamide as a crosslinking agent was diluted with water to 50 mass%.
Next, 1 mol% of a water-soluble azo initiator (V-50, manufactured by Wako Pure Chemical Industries, Ltd.) was added to 100 mol% of the total amount of 2-acrylamido-2-methylpropanesulfonic acid and methylenebisacrylamide.
This mixed solution was dropped on the electrolyte membrane surface in a vacuum chamber, and then irradiated with visible light for 6 minutes. Then, it heated in 50 degreeC oven for 18 hours.
Next, excess polymer on the surface of the electrolyte membrane is removed, ion exchange is performed using a large excess of 1N hydrochloric acid, and then thoroughly washed with distilled water, and dried in an oven at 50 ° C., so that the hydrophilic polymer is placed in the through holes. A filled electrolyte membrane was obtained.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. The results are shown in Table 1 below.

(Example 5)
(1) Electropolishing treatment The conditions were the same as in Example 1.
(2) Degreasing treatment The conditions were the same as in Example 1.

(3) Anodizing treatment First, the degreased sample obtained above was charged with an electrolyte solution of 0.1 mol / L phosphoric acid at a voltage of 195.0 V, a liquid temperature of 3 ° C., and a liquid flow rate of 5.0 m / min. Anodizing treatment was performed for 240 minutes under the conditions. The voltage was set to a constant voltage setting of 195.0 V (± 0.1 V) using GPO-250-30R (manufactured by Takasago Seisakusho).
Next, the sample after the anodizing treatment was subjected to a film removal treatment of dipping in a 0.52 mol / L phosphoric acid aqueous solution (liquid temperature: 40 ° C.) for 42.5 minutes.
These treatments were repeated 4 times in this order.

Next, the sample after the fourth film removal treatment was anodized with an electrolyte solution of 0.5 mol / L phosphoric acid for 30 minutes under the conditions of a voltage of 195.0 V, a liquid temperature of 3 ° C., and a liquid flow rate of 3.0 m / min. Was given. The voltage was set to a constant voltage setting of 195.0 V (± 0.1 V) using GPO-250-30R (manufactured by Takasago Seisakusho).
Next, the anodized sample obtained above was anodized with an electrolyte solution of 0.5 mol / L phosphoric acid at a current density of 200 A / m ² and a liquid temperature of 3 ° C. for 720 minutes. The current was measured using a current transformer and a voltmeter, and the current flowing through the conducting wire was measured and controlled to 200 A / m ² (± 10 A / m ² ).

(4) Penetration treatment Next, an aluminum substrate was dissolved by immersion for 20 minutes at a liquid temperature of 10 ° C. using a treatment liquid in which 0.1 mol / L copper chloride was blended with 20% hydrochloric acid aqueous solution.
Thereafter, the entire sample obtained was immersed in a 5% KCl buffer solution for 10 minutes, and then only the bottom (barrier layer side) of the anodized film was immersed in a 0.1N KOH aqueous solution at 25 ° C. for 50 minutes. The bottom part of the anodic oxide film was removed, and the structure which consists of an anodic oxide film which has the micropore (through-hole) which expanded the pore diameter was produced.
The surface photograph and cross-sectional photograph (magnification 20000 times) of the obtained structure after the penetration treatment were photographed with FE-SEM and confirmed to have the following shape.
・ Thickness of structure: 70 μm
-Depth of through hole: 70 μm
-Average opening diameter of through-holes: 150 nm
・ Period of through-hole (distance between centers): 500 nm
-Ordering degree of through holes: 90%

(5) Hydration treatment One side of the structure after penetration treatment obtained above was brought into contact with ammonia water (liquid temperature 80 ° C.) adjusted to pH 11.4.
After contacting for 60 minutes, a surface photograph and a cross-sectional photograph (magnification 100000 times) were taken with an FE-SEM. As a result, an electrolyte membrane in which one side of the through hole was sealed with granular hydrate was produced. It could be confirmed.
(6) Firing This was performed under the same conditions as in Example 1.

After firing, an electrolyte membrane was prepared by filling the through holes with a hydrophilic polymer having proton conductivity in the same manner as in Example 2.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. The results are shown in Table 1 below.

(Example 6)
The process up to the firing treatment was carried out in the same manner as in Example 5 to produce an electrolyte membrane, followed by a hydrophilization treatment to produce an electrolyte membrane.
Here, in the hydrophilization treatment, the electrolyte membrane was immersed in ion exchange water, and nitric acid was added to lower the pH to 4. Thereafter, ammonia water was dropped into ion-exchanged water, the pH was returned to 7, and the ion-exchanged water was replaced and washed.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. The results are shown in Table 1 below.

(Example 7)
An electrolyte membrane was produced in the same manner as in Example 5 except that the hydration treatment was changed as follows and the hydrophilic polymer filling treatment was not performed.
Both surfaces of the structure after the penetration treatment were brought into contact with ammonia water (liquid temperature 80 ° C.) adjusted to pH 11.4.
After contacting for 60 minutes, a surface photograph and a cross-sectional photograph (magnification 100000 times) were taken with FE-SEM, and it was found that an electrolyte membrane having both sides of the through hole sealed with granular hydrate was produced. It could be confirmed.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. The results are shown in Table 1 below.

(Example 8)
An electrolyte membrane was produced in the same manner as in Example 5 except that the hydration treatment was changed as follows and the hydrophilic polymer filling treatment was not performed.
The entire structure after the penetration treatment was immersed in aqueous ammonia (liquid temperature 30 ° C.) adjusted to pH 11.4.
After contacting for 8 hours, a surface photograph and a cross-sectional photograph (magnification 100000 times) were taken with an FE-SEM, and it was confirmed that an electrolyte membrane sealed with granular hydrate was produced up to the inside of the through hole. It could be confirmed.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. The results are shown in Table 1 below.

Example 9
The process up to the firing treatment was performed in the same manner as in Example 8 to produce an electrolyte membrane, followed by a hydrophilization treatment to produce an electrolyte membrane.
Here, the hydrophilic treatment was performed in the same manner as in Example 6.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. The results are shown in Table 1 below.

( Reference example )
The electrolyte membrane was produced by performing the same process as in Example 1 until the hydration treatment.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. As a result, as shown in Table 1 below, the initial performance was the same as in Example 1, but the methanol permeability after 1 hour increased to 50 μm · kg / m ² h.

(Comparative Example 1)
The electrolyte membrane was produced by performing the same process as in Example 1 up to the penetration treatment.
About the obtained electrolyte membrane, methanol permeability and proton conductivity were evaluated by the method described above. The results are shown in Table 1 below.

(Comparative Example 2)
The solid polymer electrolyte (Nafion (registered trademark) 117) was evaluated for methanol permeability and proton conductivity by the methods described above. As a result, as shown in Table 1 below, the initial performance was the same as in Example 1, but the methanol permeability after 1 hour increased to 50 μm · kg / m ² h.

As shown in Table 1, the electrolyte membranes (Examples 1 to 9 ) fired by forming hydrates of through-holes were more methanol than the electrolyte membranes (Comparative Example 1) in which hydrates were not formed. It was found to be highly durable.
In Examples 1-9 and Reference Examples are compared with Comparative Example 2 using the conventional electrolyte membrane, maintaining a high methanol resistance, it was found that the proton selectivity is better.

DESCRIPTION OF SYMBOLS 1 Fuel cell electrolyte membrane 2 Anodized film 3 Through-hole 4 Hydrate 32 Aluminum substrate 34, 34a, 34b, 34c, 34d Anodized film 36, 36a, 36b, 36c, 36d Micropore 37 Through-hole 38, 38a, 38b, 38c, 38d Barrier layer 101, 102, 104, 105, 107, 108 Through hole 103, 106, 109 yen

Claims (3)

A method for producing an electrolyte membrane for a fuel cell using an anodized film obtained by anodizing aluminum ,
The anodic oxide film has through holes with an average pore diameter of 20 to 200 nm in the depth direction of the anodic oxide film,
Supplying an alkaline aqueous solution adjusted to pH 9 to 13 to at least a part of the through-hole to form the aluminum hydrate ,
A method for producing an electrolyte membrane for a fuel cell , wherein the anodic oxide film having the through-hole formed with the hydrate is fired to oxidize the hydrate . Furthermore, the manufacturing method of the electrolyte membrane according to claim 1 for filling a hydrophilic polymer having proton conductivity on a part of the through hole. 3. The fuel cell according to claim 1, wherein the aluminum hydrate is oxidized and transferred to at least one selected from γ-alumina, Δ-alumina, θ-alumina, α-alumina, and η-alumina. For manufacturing an electrolyte membrane for an automobile.