JPH0668157B2 - Gas permeable membrane manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a gas-permeable membrane that is suitable for use as an electrode or the like of an aqueous solution electrolyzer.

"Prior art and its problems" Electrolyzers used for electrolysis of aqueous solutions are conventionally equipped with a container in which a solution is stored, a cathode and an anode provided in the container, and electrolysis generated in these anodes and cathodes. It was composed of a diaphragm provided between both electrodes to prevent mixing of the product.

The diaphragm of this type of electrolysis device is generally made of compression-molded asbestos or the like.

However, it has been pointed out that asbestos has a carcinogenic property and the like, and there have been various dissatisfactions with the installation of an electrolytic device having such a diaphragm.

In order to deal with such a problem, it has been proposed to use a film having both gas permeability and conductivity.

However, when a film of this type is manufactured by a conventional manufacturing method, it has been unsatisfactory that the pressure resistance of the film is significantly reduced when the film is provided with good gas permeability and conductivity.

"Object of the invention" The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manufacturing method capable of manufacturing a gas permeable membrane having good gas permeability and conductivity and excellent pressure resistance. And

"Means for Solving Problems" In the production method of the present invention, a gas permeable membrane is produced by the following steps.

Fine particles of the catalyst carrier, fine particles of the binder material and the liquid lubricant are kneaded to form a paste-like mixture,
This product is pressed to form a sheet, and a sheet A to be a carrier of the reaction layer is prepared. Further, as the fine particles that become the carrier of the catalyst, hydrophilic carbon fine particles and water-repellent carbon fine particles are mixed and used. Further, when the paste-like mixture is pressed to form a sheet, the sheet A is formed so that the hydrophilic portions and the water-repellent portions are finely distributed in a mesh shape.

At the same time, conductive fine particles, binder material fine particles, and a liquid lubricant are kneaded to form a paste-like mixture, which is pressed to form a sheet, which serves as a gas permeation layer. To create.

These sheets A and B are overlapped and pressed together to reduce the thickness while joining them.

Then, this is subjected to a drying treatment.

Next, this is further heat-treated.

This is hot pressed to further reduce the thickness.

FIG. 1 shows an example of a gas permeable membrane produced by the method for producing a gas permeable membrane of the present invention, wherein reference numeral 1 is a reaction layer and reference numeral 2 is a gas permeable layer.

The reaction layer 1 is formed by supporting and fixing a catalyst on a carrier, and the carrier of the reaction layer 1 is formed from the sheet A. Further, the gas permeation layer 2 is formed from the sheet B.

Alumina (Al ₂ O
₃ ), various particles such as fine particles made of ceramics such as silica (SiO ₂ ), fine particles made of an organic polymer compound, or fine particles made of an electrically conductive material can be used. Among them, the conductive fine particles are preferably used because the electric resistance of the reaction layer 1 can be reduced. Such conductive fine particles include metals such as iron, aluminum, silver, copper and gold, amorphous carbon, carbon such as graphite, zirconia ceramics, β-alumina ceramics, boron compounds [lanthanum boride (LaB ₆ ), Titanium boride (Ti
B ₂ )] and other conductive ceramics. Among them, carbon is preferably used because it has excellent water repellency and corrosion resistance, and the obtained gas permeable membrane has a long life and good chemical resistance.

As the conductive fine particles, those having a particle size of 0.5 μm or less are preferably used. If the particle size exceeds 0.5 μm, it is produced, but there is a disadvantage that a large diameter hole is formed in the reaction layer 1 of the gas permeable membrane.

Further, as the binder material used for forming the sheet A, various materials having a binder function such as a low melting point metal and an organic polymer compound can be used, but usually an organic polymer compound is preferably used.

As suitable organic polymer compounds, various synthetic resin materials such as fluororesin, silicon resin, polyethylene, polypropylene, polyacrylonitrile, polyvinyl chloride, polycarbonate and polyethylene terephthalate can be used. Above all, polytetrafluoroethylene (PT
FE), polychlorotrifluoroethylene, polyvinylidene fluoride, and fluororesins such as tetrafluoroethylene-hexafluoropropylene copolymer are suitable. Among them, PTFE is particularly preferably used because it has excellent corrosion resistance that is not attacked by acid or alkali and has excellent water repellency, and the obtained gas permeable membrane has long life and chemical resistance. To be

The reaction layer 1 formed from the sheet A preferably has a structure in which hydrophilic portions and water-repellent portions are finely distributed in a knitted pattern so as to be able to appropriately contact the aqueous solution. In order to form the reaction layer 1 having such a structure, hydrophilic fine particles and water-repellent fine particles are mixed and used when the sheet A is prepared. Examples of such fine particles include water-repellent general carbon black, and hydrophilic particles such as Vulcan XC-72R (hydrophilic carbon, trade name: manufactured by Vulcan Cabot). In addition, when the sheet A is formed, if the hydrophilic portion and the water-repellent portion have a fine mesh-like structure,
Compared with the case where the sheet is composed of only the hydrophilic portion or the case where the sheet is composed of only the water-repellent portion, it has a better gas permeability and can improve the reaction efficiency.

As the liquid lubricant used when kneading the fine particles serving as the carrier of the catalyst and the fine particles serving as the binder, various solvents can be used as long as they do not dissolve these fine particles, but an organic solvent such as naphtha is preferably used.

The mixture of the fine particles and the liquid lubricant is pressure-molded into a sheet A. The thickness of the sheet A is
It is set to be considerably thicker than the desired thickness of the reaction layer 1 of the gas permeable membrane.

The conductive fine particles used when forming the sheet B forming the gas permeation layer 2 are the same as the conductive fine particles mentioned as the material for forming the sheet A forming the reaction layer 1, that is, silver, copper, gold. Examples of the fine particles include metals such as, amorphous carbon, carbon such as graphite, and the like.

The conductive fine particles used when creating this sheet B are
A particle size of 0.1 μm or less is suitable. If the particle size exceeds 0.1 μm, the disadvantage that large holes are formed in the gas permeation layer 2 occurs.

An organic polymer compound is preferably used as the binder material used when forming the sheet B. As such an organic polymer compound, the same compounds as those mentioned in the above sheet A can be used.

When the organic polymer compound is used as the binder material in this way, the addition amount of the organic polymer compound is usually, for example, when PTFE is used as the organic polymer compound and carbon black is used as the conductive fine particles. The weight ratio of PTFE to the total amount is about 10% to 60%. When the amount of the organic polymer compound added exceeds 60%, the electric resistance of the gas permeation layer 2 formed becomes large and the gas permeability of the gas permeation layer 2 deteriorates. Also, if the addition amount is less than 10%, the bonding of the conductive fine particles becomes insufficient, and the strength of the gas permeation layer 2 decreases.

As in the case of the sheet A, the liquid lubricant used when kneading the conductive fine particles and the fine particles to be the binder is
Organic solvents such as naphtha are preferably used.

A mixture of these fine particles and a liquid lubricant is pressure-molded to form a sheet B. The thickness of the sheet B is
It is set to be considerably thicker than the desired thickness of the gas permeation layer 2 of the gas permeation membrane.

The sheets A and B produced as described above are superposed, then pressed against each other by a roller or the like to be integrated and thinned.

After this, the joined sheets A and B are subjected to a drying process to remove the liquid lubricant.

Next, the dried product is subjected to heat treatment.
The heat treatment is a treatment for weakly binding the binder fine particles, and is performed at a temperature slightly lower than the melting temperature of the binder fine particles and a temperature slightly lower than the gelling temperature of fluororesin such as PTFE. In particular,
When PTFE is used as a binder, it is desirable to carry out at about 280 ° C.

The sheet after the heat treatment is further thinned by hot pressing. The temperature applied during hot pressing is
It is carried out at a temperature above the temperature at which the binder fine particles melt, or above the temperature at which a fluororesin such as PTFE gels. Specifically, when PTFE is used as a binder, it is desirable to carry out at about 380 ° C.

In the production method of the present invention, the step of supporting the catalyst on the portion formed by the sheet A is not particularly limited, but it is usually performed after the hot pressing step.

As a method for supporting the catalyst, a method in which a solution in which the catalyst is dissolved (catalyst solution) is applied or sprayed on the surface of the sheet to permeate the inside of the sheet and then dried is convenient. By doing so, the catalyst is supported even inside the reaction layer 1.

As the catalyst to be used, an iron group element such as nickel (Ni), cobalt (Co), iron (Fe) or platinum (Pt), ruthenium (R) that promotes a chemical reaction such as electrolysis is used.
u), gold (Au), silver (Ag), copper (Cu), chromium (Cr) manganese (Mn), palladium (Pd), and other noble metal elements, or oxides thereof or catalysts composed of alloys thereof, etc. Stuff available. Among them, for electrolysis of an aqueous solution or the like, a catalyst made of Ni, Pt, Ru, or the like is preferably used because the electrolysis efficiency can be significantly improved.

Since the carrier of the reaction layer 1 of the gas permeable membrane produced in the above steps is porous, there is an advantage that a large amount of catalyst can be supported. The diameter of the holes in this carrier is preferably about 0.5 μm to 0.01 μm.

When the diameter of the reaction layer 1 exceeds 0.5 μm, the strength of the reaction layer 1 decreases. On the other hand, if the diameter is less than 0.01 μm, it becomes difficult for the solution to permeate the reaction layer 1, and only the surface of the reaction layer 1 contributes to reactions such as electrolysis and the reaction efficiency decreases.

Further, the porosity of the reaction layer 1 is preferably about 40% to 80%.

If the porosity of the carrier forming the reaction layer 1 exceeds 80%, the resulting reaction layer 1 is not preferable because the pressure resistance is insufficient. If the porosity is less than 40%, a sufficient amount of catalyst cannot be supported, which is not preferable.

Further, the reaction layer 1 is preferably formed to have a thickness of about 1.0 mm or less. When the thickness of this reaction layer 1 exceeds 1.0 mm,
The gas generated in the reaction layer 1 is less likely to permeate into the gas permeation layer 2, and the gas permeability of the gas permeation membrane is impaired.

The gas permeation layer 2 of the gas permeation membrane produced by the production method of the present invention is a porous and electrically conductive layer in which conductive fine particles are bonded via a binder or by sintering or the like.

The holes formed in the gas permeation layer 2 are preferably continuous holes having a diameter of 0.5 μm or less, preferably 800 Å or less. Gas permeation layer 2 when the hole diameter exceeds 0.5 μm
Can penetrate not only the molecules in the gas state but also the molecules in the liquid state, which causes a disadvantage that the gas-liquid separation function is deteriorated.

The porosity of the gas permeation layer 2 is preferably about 40% to 80%. When the porosity of the gas permeation layer 2 exceeds 80%, the pressure resistance of the obtained gas permeation membrane becomes insufficient,
If the porosity is less than 40%, the gas permeation rate of the gas permeation layer 2 decreases, and the decomposition product gas cannot be efficiently released.

The gas permeation layer 2 is preferably formed to have a thickness of about 0.3 mm to 2 mm. If the thickness of the gas permeation layer 2 exceeds 2 mm, the gas permeation rate of the gas permeation layer 2 will decrease, and if it is less than 0.3 mm, the strength of the gas permeation layer 2 will decrease.

[Examples] Hereinafter, the method for producing a gas permeable membrane of the present invention will be described in detail.

The explanation will be given by taking a gas permeable membrane using PTFE as an organic polymer compound as a binder and carbon black as conductive fine particles as an example.

First, to prepare the sheet A, 70 parts by weight of carbon black having an average particle size of 0.042 μm and PT having an average particle size of 0.25 μm are used.
A mixture A formed by sufficiently mixing 30 parts by weight of FE and a mixture B formed by sufficiently mixing Vulcan XC-72R having hydrophilicity and 70 parts by weight of PTFE having an average particle diameter of 0.25 μm were prepared. Then mix these mixtures A and B with A: B.
= 4: 6, mixed with an organic solvent (naphtha),
Kneaded uniformly. Sheet A with a thickness of 0.4 mm when pressed
Was molded.

Separately, to make sheet B, the average particle size is 0.04
70 parts by weight of 2 μm carbon black and an average particle size of 0.25 μ
Mixture C was prepared by thoroughly mixing 30 parts by weight of PTFE of m. Then, an organic solvent (naphtha) was added to the mixture to form a paste, which was sufficiently kneaded so as to be uniform. This was pressed to form a sheet B having a thickness of 2.5 mm.

The two types of sheets A and B formed in this manner were superposed and pressed together by a roller to integrally join them to form a sheet having a thickness of 0.9 mm. This was dried to volatilize the solvent used, and then heat-treated in a heating furnace at 280 ° C. Next, this is hot-pressed at 380 ° C. for a predetermined time,
It was formed into a sheet having a thickness of 0.8 mm.

Then, a solution in which a catalyst was dissolved (catalyst solution) was applied to the portion formed by the sheet A so that the solution was permeated into the sheet, and then dried to carry the catalyst.

The method of manufacturing the gas permeable membrane of the present invention is not limited to the above-mentioned embodiment. For example, a metal net may be attached to the produced gas permeable membrane if necessary. When a metal net is attached, the position of the metal net is on the surface of the gas permeation layer 2, the reaction layer 1
Of the gas permeation layer 2 and the reaction layer 1. As the metal net, one made of a metal having good electric conductivity such as copper is preferably used. Further, the mesh of the metal net is preferably about 30 to 100,
The metal fibers forming the metal net preferably have a diameter of about 100 μm to 500 μm.

Such attachment of the metal net is performed, for example, by setting the metal net at an appropriate position when the sheets A and B are superposed and hot pressing the metal net.

"Example 1" The properties of the gas permeable membrane produced by the production method of the present invention were examined.

First, the relationship between the gas permeation rate of the gas permeation layer 2 and the composition of the gas permeation layer 2 was investigated.

First, a film corresponding to the gas permeation layer 2 was made using PTFE and carbon black. Various types of this membrane were prepared by changing the proportion of PTFE. Use PTFE with an average particle size of 0.25 μm, and use carbon black with an average particle size of 0.042 μm.
Use one of these and combine these PTFE and carbon
It was set to 00 wt%.

The membrane used in this experiment was manufactured as follows.

First, a mixture was prepared by thoroughly mixing carbon black and PTFE. Naphtha was added to this and kneaded sufficiently, and then this was formed by a roll method at room temperature to a thickness of 1.
Sheet B of 01 mm was used.

The sheet B thus formed was dried, the solvent used was volatilized, and then heat-treated in a heating furnace at 280 ° C. Then, 1 g of each of these was hot-pressed to form a sheet having an area of 12.56 cm ² and a thickness of 1 mm and fired. The hot press conditions are temperature 380 ° C. and pressure 600.
It was kg / cm ² and the time was 3 seconds.

Moreover, when the diameter of the holes formed in the obtained film was examined by a mercury porosimeter, all were 800 to 200 Å.

In this gas permeation experiment, a membrane was set in the center of a closed container, the container was airtightly partitioned into two chambers, and hydrogen gas was introduced into one chamber at a gauge pressure of 1 kg / cm ² and kept at atmospheric pressure. The measurement was performed by measuring the amount of hydrogen gas that permeated into the other chamber.

Results are shown in FIG.

As can be seen from FIG. 2, the gas permeation layer 2 obtained by the method for producing a gas permeation membrane of the present invention has a higher gas permeation rate as the proportion of PTFE decreases.

"Experimental Example 2" It was examined how the gas permeation rate of the gas permeation layer 2 produced by the manufacturing method of the present invention changes depending on the differential pressure.

The membrane used in this experiment was PTFE3 with an average particle size of 0.25 μm.
The diameter of the formed holes was 700 to 200Å, which consisted of 0 wt% and 70 wt% of carbon having an average particle diameter of 0.042 μm and had a film thickness of 1 mm and 0.5 mm. The creation of the membrane
It carried out by the method similar to Experimental example 1.

In the experiment, a membrane was set in the center of a closed container, the container was airtightly divided into two chambers, one chamber was maintained at atmospheric pressure, and the other chamber had a pressure difference of 0.5 atm. The amount of hydrogen gas or oxygen gas permeating into one chamber under each condition was measured while introducing hydrogen gas or oxygen gas to 1.0 atm ....

Results are shown in FIG.

From FIG. 3, it was confirmed that the gas permeation rate of the gas permeation layer 2 produced by the method for producing a gas permeation membrane of the present invention is proportional to the differential pressure. It was also confirmed that hydrogen has a higher permeation rate than oxygen, and that the gas permeation membrane obtained by the production method of the present invention has a higher permeation rate as the gas permeation layer 2 is thinner.

"Experimental Example 3" In the method for producing a gas permeable membrane of the present invention, the gas permeable layer 2
It was examined how the porosity of No. 1 changes depending on the press pressure when forming the gas permeation layer 2 and the pretreatment applied to PTFE.

First, a film corresponding to the gas permeation layer 2 was prepared in the same manner as in Example 1. At that time, the pressure of the hot press is 10 to 60
Varyed between 0 kg / cm ² . The PTFE used had an average particle size of 0.25 μm, and 30 parts by weight of this PTFE was mixed with 70 parts by weight of carbon having an average particle size of 0.042 μm. This mixture was subjected to the following three kinds of treatments, that is, freeze-drying treatment, freezing treatment and alcohol dipping treatment.

Each 1.0 g of the mixture subjected to these treatments was molded. The molding temperature during hot pressing was 380 ° C. in terms of material temperature. The average pore diameter of the formed membrane is 500.
It was about Angstrom.

Mercury was pressed into the molded film to measure the amount of holes in the film.

Results are shown in FIG.

From FIG. 4, it was confirmed that the higher the press pressure, the lower the porosity. Further, it was confirmed that when a mixture of PTFE and carbon was immersed in alcohol, a gas permeable membrane could be formed although the porosity was high.

"Experimental Example 4" It was examined how the porosity of the gas permeation layer 2 produced by the method for producing a gas permeation membrane of the present invention changes depending on the proportion of PTFE.

A film corresponding to the gas permeation layer 2 was prepared in the same manner as in Example 4. Freeze-treated PTFE is used, and P
The case of TFE: carbon black = 30 parts by weight: 70 parts by weight and 40 parts by weight: 60 parts by weight was examined. The diameter of the pores of the formed film was about 500Å on average.

Mercury was pressed into the formed film to measure the amount of holes in the film.

Results are shown in FIG.

From FIG. 5, it was confirmed that the higher the proportion of PTFE, the lower the porosity. Further, it was confirmed that in the case where the proportion of PTFE was high, the porosity was sharply reduced when the press pressure was increased.

"Experimental Example 5" The relationship between the porosity and the water pressure resistance of the gas permeation layer 2 produced by the method for producing a gas permeation membrane of the present invention was examined.

The membrane prepared in Experimental Example 3 was liquid-tightly attached to the side wall having the opening of the container, and water was injected into the container. Water pressure was applied to the water in the container, and the water pressure when water permeated through the membrane was examined to determine the water pressure resistance.

The results are shown in Fig. 6.

From FIG. 6, it was confirmed that the gas permeation layer 2 produced by the method for producing a gas permeation membrane of the present invention has higher water pressure resistance as the porosity is lower.

[Experimental Example 6] It was examined how the water pressure resistance of the gas permeation layer 2 produced by the method for producing a gas permeation membrane of the present invention changes depending on the proportion of PTFE.

The experiment was performed by liquid-tightly attaching the membrane prepared in Experimental Example 4 to the side wall having the opening of the container, injecting water into the container and applying pressure.

The results are shown in Fig. 7.

From FIG. 7, the amount of PTFE is 30 wt% and 40 wt%
It was confirmed that there is no significant difference in the water pressure resistance of the gas permeation layer 2 from that of No.

"Experimental example 7" The relationship between the water pressure resistance of the gas permeation layer 2 produced by the method for producing a gas permeation membrane of the present invention and the press pressure during production was examined.

The membrane prepared in Experimental Example 3 was liquid-tightly attached to the side wall having the opening of the container, water was injected into the container, and the water pressure resistance of the film was examined.

The results are shown in Fig. 8.

From FIG. 8, it was confirmed that the gas permeation layer 2 of the gas permeation membrane produced by the production method of the present invention had a higher water pressure resistance as it was produced at a higher pressing pressure.

[Experimental Example 8] It was examined how the water pressure resistance of the gas permeation layer 2 produced by the method for producing a gas permeation membrane of the present invention changes depending on the proportion of PTFE.

The experiment was carried out by liquid-tightly attaching the membrane prepared in Experimental Example 4 to the side wall having the opening of the container, injecting water into the container and applying pressure.

The results are shown in Fig. 9.

From FIG. 9, the gas permeable layer 2 produced by the method for producing a gas permeable membrane of the present invention has a higher proportion of PTFE,
It was also confirmed that the higher the press pressure during production, the higher the water pressure resistance.

"Experimental Example 9" Utilizing the gas permeable membrane manufactured by the manufacturing method of the present invention,
A gas separation and purification device 3 was prototyped to separate oxygen from air.

FIG. 10 shows a schematic configuration of a prototype gas separation and purification device 3. This apparatus comprises a source gas chamber 4, a solution flow chamber 5 and a gas recovery chamber 6 arranged in parallel,
A gas permeable membrane A is provided between the source gas chamber 4 and the solution flow chamber 5,
A gas permeable membrane B separates the gas recovery chamber 6 and the solution flow chamber 5 from each other. The gas permeable membranes A and B are attached so that the reaction layers 1 and 1 face the solution flow chamber 5 side, respectively. The distance between the membranes A and B is set to 1 mm.

The specifications of the gas permeable membranes A and B used in this experiment are as follows.

I) Gas permeation membrane A Structure: 0.1 mm thick reaction layer 1 and 0.5 mm thick gas permeation layer 2
A three-layer structure in which a copper net and a copper net are sequentially stacked.

Area: 900 cm ² a) Reaction layer 1 Composition: 70 parts by weight of carbon, average particle size 0.038 μm PTFE 30 parts by weight, average particle size 0.25 μm Catalyst: Platinum-based, average particle size 50 Å b) Gas permeation layer 2 Composition: 70 parts carbon Part, average particle size 0.042 μm PTFE 70 parts by weight, average particle size 0.25 μm Porosity: 65% Pore diameter: Average 450Å II) Gas permeable membrane B Structure: 0.1 mm thick reaction layer 1 and 0.5 mm thick Gas permeation layer 2
A three-layer structure in which a copper net and a copper net are sequentially stacked.

Area: 900 cm ² a) Reaction layer 1 composition: 30 parts by weight of carbon, average particle size 0.048 μm PTFE 30 parts by weight, average particle size 0.25 μm Catalyst: nickel-based, average particle size 300Å b) Gas permeation layer 2 composition: 65 parts carbon Part, average particle size 0.042 μm PTFE 35 parts by weight, average particle size 0.25 μm Porosity: 65% Pore diameter: Average 450 Å Solution flow chamber of gas separation and purification device 3 with such gas permeable membranes A and B attached 5, potassium hydroxide (KO
A 20 wt% solution of H) was supplied at a rate of 0.12 / min and a pressure of 2.2 kg / cm ² · G (gauge pressure). In addition, 0.01kg / cm in the source gas chamber 4
^2. G air was supplied at 80 / min. Then, using the gas permeation film A as a cathode and the gas permeation film B as an anode, a voltage of 0.96 V lower than the voltage (1.25 V) necessary for electrolysis of water and a current of 450 A were applied between the gas permeation films A and B.

When the apparatus was operated under the above conditions, oxygen with a purity of 99.99% and a pressure of 2 kg / cm ² · G (about 3 atm) was obtained at 1.56 per minute (standard state) from the gas recovery chamber 6.

Then, instead of the above potassium hydroxide solution, 20 wt%
When a similar experiment was conducted using a sodium hydroxide solution, it was found that 1.55 / min oxygen (purity 99.99
%) Could be separated.

Since the gas permeable membrane produced by the manufacturing method of the present invention has a high pressure resistance strength (about 20 kg / cm ² or more), the gas separation / purification device 3 equipped with the gas permeable membrane of the present invention is equipped with a pressure in the solution flow chamber 5. Can be kept high. With this device, a gas having a pressure almost equal to the pressure in the solution flow chamber 5 can be obtained,
By increasing the pressure in the solution flow chamber 5, a large amount of high-pressure oxygen can be produced.

"Experimental Example 10" Using the same gas separation and purification apparatus 3 as in Experimental Example 9, hydrogen gas was purified.

The specifications of the gas permeable membranes A and B used in this experiment are as follows.

I) Gas permeation membrane A Structure: 0.1 mm thick reaction layer 1 and 0.5 mm thick gas permeation layer 2
A three-layer structure in which a copper net and a copper net are sequentially stacked.

Area: 900 cm ² a) Reaction layer 1 Composition: 70 parts by weight of carbon, average particle size 0.038 μm PTFE 30 parts by weight, average particle size 0.25 μm Catalyst: Platinum-based, particle size 50 Å b) Gas permeation layer 2 Composition: 70 parts by weight of carbon , Average particle size 0.042 μm PTFE 30 parts by weight, average particle size 0.25 μm Porosity: 64% Pore size: Average 440Å II) Gas permeation membrane B Structure: 0.1 mm thick reaction layer 1 and 0.5 mm thick gas Penetration layer 2
A three-layer structure in which a copper net and a copper net are sequentially stacked.

Area: 900 cm ² a) Reaction layer 1 Composition: 70 parts by weight of carbon, average particle size 0.038 μm PTFE 30 parts by weight, average particle size 0.25 μm Catalyst: Platinum-based, particle size 50 Å b) Gas permeation layer 2 Composition: 70 parts by weight of carbon , Average particle diameter 0.042 μm PTFE 30 parts by weight, average particle diameter 0.25 μm Porosity: 64% Pore diameter: Average 440 Å Solution flow chamber 5 of gas separation and purification apparatus 3 to which such gas permeable membranes A and B are attached A 5% by weight dilute sulfuric acid solution is added to the solution.
It was supplied at 2 / min and 2.2 kg / cm ² · G. In addition, 0.01 kg of 99% pure hydrogen gas containing oxygen and nitrogen is supplied to the source gas chamber 4.
/ Cm ² · G, 8 / min. The gas permeable membrane A is used as an anode and the gas permeable membrane B is used as a cathode.
Voltage between 0.2V (This value is the minimum voltage 1.25 required for water electrolysis.
And lower than V), a current of 900 A was applied.

When the apparatus was operated under the above conditions, hydrogen gas having a purity of 99.999% and a pressure of 2 kg / cm ² · G was converted from the gas recovery chamber 6 to the standard state, and 6.26 per minute was obtained.

In this apparatus, the energy required to purify 1 m ³ of hydrogen gas in the standard state was 0.48 kw · hr. In contrast, 1.0kw · hr / m ³ in the case of hydrogen purification using a conventional palladium membrane, 1.2kw · hr / m ³ in the case of cryogenic hydrogen purification
Therefore, it was confirmed that the gas separation and purification apparatus 3 provided with the gas permeable membrane produced by the production method of the present invention can efficiently purify hydrogen gas.

Further, in this device 3, it is considered that the energy efficiency can be further improved by further reducing the distance between the films A and B.

"Experimental Example 11" A gas generator 7 using a gas permeable membrane produced by the production method of the present invention was prototyped to produce hydrogen gas and oxygen gas.

FIG. 11 shows a schematic configuration of the prototype gas generator 7. In this device, generated gas recovery chambers 9 and 10 are provided on both sides of the solution distribution chamber 8. The solution distribution chamber 8 and the generated gas recovery chambers 9 and 10 are partitioned by gas permeable membranes A and B, respectively. Has been. The gas permeable membranes A and B are attached so that the reaction layers 1 and 2 face the solution flow chamber 8 side, respectively, and the distance between the membranes A and B is set to 1 mm.

The specifications of the gas permeable membranes A and B used in this experiment are as follows.

I) Gas permeation membrane A Structure: 0.1 mm thick reaction layer 1 and 0.5 mm thick gas permeation layer 2
A three-layer structure in which a copper net and a copper net are sequentially stacked.

Area: 900 cm ² a) Reaction layer 1 Composition: Carbon 65 parts by weight, average particle size 0.042 μm PTFE 35 parts by weight, average particle size 0.25 μm Catalyst: RuO ₂ system, particle size 100 Å b) Gas permeation layer 2 Composition: Carbon 70 parts by weight Part, average particle size 0.042 μm PTFE 30 parts by weight, average particle size 0.25 μm Porosity: 65% Pore diameter: Average 460Å II) Gas permeation membrane B Structure: 0.1 mm thick reaction layer 1 and 0.5 mm thick Gas permeation layer 2
A three-layer structure in which a copper net and a copper net are sequentially stacked.

Area: 900 cm ² a) Reaction layer 1 Composition: 70 parts by weight of carbon, average particle size 0.038 μm PTFE 30 parts by weight, average particle size 0.25 μm Catalyst: Platinum-based, particle size 50 Å b) Gas permeation layer 2 Composition: 70 parts by weight of carbon , Average particle size 0.042 μm PTFE 30 parts by weight, average particle size 0.25 μm Porosity: 65% Pore diameter: Average 450 Å In the solution flow chamber 8 of the gas generator 7 with such gas permeable membranes A and B attached. 20 mol% dilute sulfuric acid solution 0.12
/ Min, 2.2kg / cm ² · G while supplying gas permeation membrane A,
A voltage of 1.8 V and a current of 900 A were applied between B. On this occasion,
The gas permeable membrane A was used as an anode and the gas permeable membrane B was used as an anode.

When the apparatus was operated under the above conditions, the generated gas recovery chamber 9
It was possible to obtain oxygen gas at 3.13 per minute (under standard conditions) and hydrogen gas from the evolved gas recovery chamber 10 at 6.25 per minute (under standard conditions).

Then, instead of the above sulfuric acid solution, an alkaline solution (25
A similar experiment was conducted using a wt% sodium hydroxide solution), a neutral solution (20 wt% sodium sulfate solution), etc., and similarly, oxygen gas and hydrogen gas could be efficiently produced.

When one of the permeation membranes A and B was replaced with an electrode of a conventional electrolyzer and the gas generator 7 was operated, oxygen gas and hydrogen gas could be similarly obtained. When the device 7 was operated in this manner, the life of the film could be extended.

Experimental Example 12 Carbon dioxide gas and hydrogen gas were produced using the gas generator 7 of Experimental Example 11.

The specifications of the gas permeable membranes A and B used in this experiment are as follows.

I) Gas permeation membrane A Structure: 0.1 mm thick reaction layer 1 and 0.5 mm thick gas permeation layer 2
A three-layer structure in which a copper net and a copper net are sequentially stacked.

Area: 900 cm ² a) Reaction layer 1 Composition: Carbon 70 parts by weight, average particle size 0.042 μm PTFE 30 parts by weight, average particle size 0.25 μm Catalyst: Platinum-based catalyst with particle size 50 Å and RuO with particle size 100 Å
₂ type catalyst b) Gas permeation layer 2 Composition: Carbon 70 parts by weight, average particle size 0.042 μm PTFE 30 parts by weight, average particle size 0.25 μm Porosity: 65% Pore diameter: Average 450Å II) Gas permeation membrane B Structure: 0.1 mm thick reaction layer 1 and 0.5 mm thick gas permeation layer 2
A three-layer structure in which a copper net and a copper net are sequentially stacked.

Area: 900 cm ² a) Reaction layer 1 Composition: 70 parts by weight of carbon, average particle size 0.038 μm PTFE 30 parts by weight, average particle size 0.25 μm Catalyst: Platinum-based, particle size 50 Å b) Gas permeation layer 2 Composition: 70 parts by weight of carbon , Average particle size 0.042 μm PTFE 30 parts by weight, average particle size 0.25 μm Porosity: 65% Pore diameter: Average 450Å First, 0.5 mol / methanol in dilute sulfuric acid solution 10 vol%
A mixed raw material solution was prepared. And the gas generator 7
0.1 ml / min, 2.0 kg / cm of this raw material solution in the solution circulation chamber 8 of
^The voltage between the gas permeation membranes A and B is 0.6-0.
7V and current 450A were applied. At this time, the gas permeable membrane A
Was used as an anode and the gas permeation film B was used as a cathode. The temperature of the raw material solution was 65 ° C.

When the apparatus was operated under the above conditions, the generated gas recovery chamber 9
From the purity of 99.9%, pressure of 1.5kg / cm ² · G carbon dioxide gas is converted to the standard state 1.03 per minute, from the generated gas recovery chamber 10 purity of 99.9%, pressure of 1.5kg / cm ² · G of hydrogen gas is standard I was able to get 6.24 per minute in terms of status.

In this device, the depolarizing effect of methanol makes it possible to significantly reduce the power consumption.

Here, the features of the gas separation / purification device 3 and the gas generator 7 having the gas permeable membrane produced by the manufacturing method of the present invention will be listed.

By using the gas permeable membrane produced by the production method of the present invention, it is possible to produce an apparatus capable of producing and purifying not only oxygen gas and hydrogen gas but also various gases such as chlorine gas as long as it is an ionizable gas. You can

"Effects of the Invention" As described above, in the method for producing a gas permeable membrane of the present invention, first, a fine particle obtained by mixing hydrophilic carbon fine particles and a water repellent carbon fine particle, which are catalyst carriers, and a binder material A paste-like mixture is prepared from the fine particles and the liquid lubricant, and this mixture is pressed to form a sheet to form a sheet A in which hydrophilic portions and water-repellent portions are finely distributed in a net-like shape, and at the same time, conductive A paste-like mixture is prepared from the fine particles having the property, the fine particles of the binder material, and the liquid lubricant, and this mixture is pressed to form a sheet B, and then the sheets A and B are formed. In order to produce a gas permeable membrane, the layers are thinned while being superposed and pressure-bonded to each other, then subjected to a drying treatment and a heat treatment in this order, and then hot pressed to further reduce the thickness. Therefore, according to the manufacturing method of the present invention, it has good gas permeation performance and conductivity, and also has excellent pressure resistance (2
It is possible to produce a gas-permeable membrane having a pressure of 0 kg / cm ² or more). Therefore, according to the gas permeation membrane produced by the manufacturing method of the present invention, the pressure of the solution flow chamber partitioned by the gas permeation membrane can be set high, and a small amount of high-pressure gas can be purified or produced in a small size. The device and the gas generator can be configured. In the case where the sheet A is prepared, if the hydrophilic portion and the water repellent portion have a structure in which the hydrophilic portion and the water repellent portion are finely distributed in a mesh shape, the sheet may be formed only from the hydrophilic portion or the water repellent portion. Compared with the case where the sheet is formed from only the sheet, it has a superior gas permeability and can improve the reaction efficiency.

Further, since the gas permeable membrane produced by the production method of the present invention has excellent pressure resistance, the gas separation and purification device and the gas generator using this membrane can apply pressure to the electrolytic solution. . Therefore, according to the gas permeable film produced by the manufacturing method of the present invention, it is possible to provide an apparatus having a gas pressure increasing function which can be obtained without mixing high-pressure gas from each electrode.

Further, since the gas permeation membrane produced by the production method of the present invention has a good gas-liquid separation function, the gas separation and purification apparatus and the gas generator equipped with this membrane have high purity (9
9.999% or more) will be able to obtain gas.

[Brief description of drawings]

FIG. 1 is a sectional view showing an experimental example of a gas permeable membrane produced by the manufacturing method of the present invention, and FIGS. 2 to 9 show the results of the experiment. FIG. 3 is a graph showing the relationship between the velocity and the composition of the gas permeation layer, FIG. 3 is a graph showing the relationship between the gas permeation rate of the gas permeation layer and the differential pressure, and FIG. 4 is the porosity of the gas permeation layer and the time of manufacture. A graph showing the relationship between the press pressure and the pretreatment applied to PTFE,
FIG. 5 is a graph showing the relationship between the porosity of the gas permeation layer and the press pressure and the proportion of PTFE during manufacturing, and FIG. 6 is a graph showing the relationship between the porosity of the gas permeation layer and the water pressure resistance. Fig. 8 is a graph showing the relationship between the water pressure resistance of the gas permeation layer and the proportion of PTFE, Fig. 8 is a graph showing the relationship between the water pressure resistance of the gas permeation layer and the press pressure during manufacturing, and Fig. 9 is the water pressure resistance of the gas permeation layer. PT
Graphs showing the relationship of the FE ratio, FIGS. 10 and 11
Each of the figures is a schematic configuration diagram showing a gas generator using the gas permeable membrane of the present invention. 1 ... Reactive layer, 2 ... Gas permeable membrane.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI technical display location // C01B 3/50 13/02 Z 9152-4G (72) Inventor Choichi Furuya Kofu City, Yamanashi Prefecture Ote 2-chome 4-3-31 (56) References JP-A-59-133386 (JP, A) JP-A-55-148778 (JP, A)

Claims (1)

[Claims] 1. A method for producing a gas permeable membrane, wherein a reaction layer comprising a carrier on which fine particles are bound and a catalyst supported thereon is laminated on a porous gas permeable layer on which conductive fine particles are bound. First of all, the hydrophilic carbon fine particles and the water-repellent carbon fine particles which become the carrier of the catalyst, the fine particles of the binder material and the liquid lubricant are kneaded to form a paste-like mixture, which is pressed to form a sheet. A sheet A having a structure in which hydrophilic portions and water-repellent portions are finely distributed in a mesh shape and serving as a carrier of a reaction layer is formed, and at the same time, conductive fine particles, binder material fine particles, and liquid are formed. A lubricant is kneaded to form a paste-like mixture, which is pressed to form a sheet to form a gas permeation layer sheet B, and then the sheets A and B are superposed and pressure-bonded to each other. While thin After that, it is dried and heat-treated in order,
Then, this is hot-pressed to further reduce the thickness, and a method for producing a gas-permeable membrane.