JP2020045550A - Method for manufacturing electrode - Google Patents

Abstract

To provide a method for manufacturing electrode, in which the cost during electrode replacement in electrolytic tank can be reduced as well as the work efficiency can be improved, and, furthermore, the electrolytic performance after repair can be maintained.SOLUTION: Provided is a method for manufacturing electrode, which is a method for manufacturing a new electrode by repairing the surface of an existing electrode, and includes a step (A) of fixing an electrode for electrolysis having a thickness of 315 μm or less to at least one region of the surface of the existing electrode.SELECTED DRAWING: None

Description

  The present invention relates to a method for manufacturing an electrode.

In the electrolysis of an aqueous solution of an alkali metal chloride such as a saline solution and the electrolysis of water (hereinafter collectively referred to as "electrolysis"), an electrolytic cell provided with a diaphragm, more specifically, an ion exchange membrane or a microporous membrane is used. The method used is used. This electrolyzer often comprises a number of electrolysis cells connected in series therein. Electrolysis is performed with a diaphragm interposed between the electrolysis cells. In the electrolytic cell, a cathode chamber having a cathode and an anode chamber having an anode are arranged back to back via a partition (back plate) or through pressing by pressing pressure, bolting, or the like.
The anode and cathode currently used in these electrolytic cells are fixed to the anode and cathode chambers of the electrolytic cell by welding, folding, etc., and then stored and transported to the customer. On the other hand, the diaphragm itself is stored alone in a state of being wound on a pipe made of vinyl chloride (PVC) and transported to the customer. The customer arranges the electrolytic cells on the frame of the electrolytic cell, and assembles the electrolytic cell with the diaphragm interposed between the electrolytic cells. Thus, the production of the electrolytic cell and the assembly of the electrolytic cell at the customer site are performed. As structures applicable to such an electrolytic cell, Patent Documents 1 and 2 disclose a structure in which a diaphragm and an electrode are integrated.

JP-A-58-048686 JP-A-55-148775

  When the electrolysis operation is started and continued, each component is degraded due to various factors, and the electrolysis performance is reduced, and each component is replaced at a certain time. The diaphragm can be relatively easily updated by withdrawing it from between the electrolysis cells and inserting a new diaphragm. On the other hand, since the anode and cathode are fixed to the electrolytic cell, when renewing the electrode, take out the electrolytic cell from the electrolytic cell, carry it out to a dedicated renewal factory, remove the fixing such as welding, peel off the old electrode, and then replace the new electrode There is a problem that a very complicated operation of installing, fixing by a method such as welding, transporting to an electrolytic plant, and returning to an electrolytic cell occurs. Here, it is conceivable to use a structure in which the diaphragm and the electrode described in Patent Documents 1 and 2 are integrated by thermocompression bonding for the above-mentioned renewal, but the structure is relatively easy at the laboratory level. However, it is not easy to manufacture the cell in accordance with an actual commercial size electrolytic cell (for example, 1.5 m in length and 3 m in width). Further, even when such a structure is used, it is inevitable that the above-mentioned complicated work will occur.

  The deterioration of the anode and the cathode does not progress uniformly over the entire surface, but tends to locally progress. As described above, even if a part of the anode or the cathode is deteriorated, it may affect the electrolytic performance. In particular, when a metal wire forming the anode or the cathode is broken due to deterioration, damage to an adjacent diaphragm is likely to occur at that portion. Thus, from the viewpoint of maintaining the electrolytic performance, it is desirable to replace even a part of the deteriorated electrode, but from the viewpoint of cost reduction, it can be said that there is room for improvement in such measures.

In view of the above, it is conceivable to repair the deteriorated electrode by applying the repair electrode only to the deteriorated portion of the deteriorated electrode and welding the metal wires constituting the electrode one by one at the corresponding locations. Can be However, in the above-mentioned welding method (welding thin metal wires constituting the electrodes one by one), there is a problem from the viewpoint of work efficiency in repairing a large area.
In addition, it is conceivable to repair an existing electrode by applying a repair electrode only to the deteriorated portion and attaching an outer peripheral portion of the electrode with a seal or an adhesive. However, in such attachment, the pressure from the electrode to the diaphragm increases in that portion due to an increase in the electrode thickness of the attached portion. In such a portion, the electrolyte solution tends to stagnate, so that the diaphragm may deteriorate and adversely affect the electrolytic performance.

  The present invention has been made in view of the above-mentioned problems of the prior art, and reduces the cost of electrode replacement in an electrolytic cell, improves work efficiency, and further maintains electrolytic performance after repair. It is an object of the present invention to provide a method for producing the same.

The present inventors have made intensive studies to solve the above problems, and as a result, have found that the above problems can be solved by using an electrode for electrolysis having a predetermined thickness, and have completed the present invention.
That is, the present invention includes the following embodiments.
[1]
A method for manufacturing a new electrode by repairing the surface of an existing electrode,
A method for manufacturing an electrode, comprising: a step (A) of fixing an electrode for electrolysis having a thickness of 315 μm or less to at least one region of the surface of the existing electrode.
[2]
The method for producing an electrode according to [1], wherein in the region, at least a part of the electrode for electrolysis penetrates the existing electrode and is fixed.
[3]
The electrode manufacturing method according to any one of [1] and [2], wherein at least a part of the electrode for electrolysis is located and fixed inside the existing electrode in the region.
[4]
The method for producing an electrode according to any one of [1] to [3], further comprising a fixing member for fixing the existing electrode and the electrode for electrolysis.
[5]
The method for producing an electrode according to any one of [1] to [4], wherein in the step (A), water is interposed between the electrode for electrolysis and the existing electrode.
[6]
The ratio of the electrode thickness T1 before the repair of the existing electrode to the electrode thickness T2 after the repair as T2 / T1 is less than 1.0 to less than 2.1, according to any of [1] to [5]. Manufacturing method of electrode.
[7]
The method for producing an electrode according to any one of [1] to [6], wherein the electrode for electrolysis has a punched shape, an expanded shape, or a mesh shape.

  ADVANTAGE OF THE INVENTION According to the manufacturing method of the electrode which concerns on this invention, the cost at the time of electrode replacement in an electrolytic cell is reduced, work efficiency is improved, and the electrolytic performance after repair can also be maintained.

It is a typical sectional view of the electrode for electrolysis in one embodiment of the present invention. 1 is a schematic cross-sectional view illustrating one embodiment of an ion exchange membrane. It is a schematic diagram for explaining the opening ratio of the reinforcement core material which constitutes an ion exchange membrane. It is a schematic diagram for explaining the method of forming the communication hole of the ion exchange membrane. FIG. 5A is a schematic cross-sectional view illustrating an embodiment in which at least a part of the electrode for electrolysis penetrates the existing electrode and is fixed. FIG. 5B is a sectional view taken along line X-X ′ of FIG. 5A. FIG. 6A is a schematic cross-sectional view illustrating an aspect in which at least a part of an electrode for electrolysis is located and fixed inside an existing electrode. FIG. 6B is a sectional view taken along line Y-Y ′ of FIG. 6A. 7A to 7C are schematic cross-sectional views illustrating an embodiment in which a thread-like fixing member is used as a fixing member for fixing an electrolysis electrode to an existing electrode. It is a schematic cross section which illustrates the aspect which fixes using an adhesive as a fixing member for fixing an electrode for electrolysis to an existing electrode. It is a typical sectional view of an electrolysis cell. It is a typical sectional view showing the state where two electrolysis cells were connected in series. It is a schematic diagram of an electrolytic cell. It is a typical perspective view which shows the process of assembling an electrolytic cell. FIG. 3 is a schematic cross-sectional view of a reverse current absorber that can be provided in the electrolytic cell.

  Hereinafter, embodiments of the present invention (hereinafter, also referred to as the present embodiment) will be described in detail with reference to the drawings as necessary. The following embodiments are exemplifications for describing the present invention, and the present invention is not limited to the following contents. Further, the attached drawings show an example of the embodiment, and the form is not to be construed as being limited thereto. The present invention can be appropriately modified and implemented within the scope of the invention. In addition, the positional relationship such as up, down, left, and right in the drawings is based on the positional relationship shown in the drawings unless otherwise specified. The dimensions and ratios in the drawings are not limited to those shown.

[Method of manufacturing electrode]
The method for manufacturing an electrode according to the present embodiment is a method for manufacturing a new electrode by repairing the surface of an existing electrode. (A) of fixing the electrode for electrolysis.
According to the method for manufacturing an electrode according to the present embodiment, since the method includes the step (A), a new electrode can be obtained only by repairing a part of the existing electrode, and the existing electrode itself is removed and replaced. Work is not required. In addition, an excessive increase in the electrode thickness of the repaired portion can be prevented, and pressing of the electrode from the electrode to the diaphragm and stagnation of the electrolyte can be prevented in that portion. That is, by the method for manufacturing an electrode according to the present embodiment, it is possible to reduce the cost of renewing the electrode in the electrolytic cell, improve the work efficiency, and maintain the electrolytic performance after the repair.

In the present embodiment, the existing electrode is assumed to be an “electrode (anode or cathode) already operated in the electrolytic cell”, and a new electrode is an existing electrode and an electrode for electrolysis as a repair member. And "electrodes that have not yet been operated". That is, it can be said that the electrolysis performance of the existing electrode is deteriorated at least as compared to before the operation, due to the operation. In addition, once the electrode manufactured as a new electrode is subjected to operation, it becomes an “existing electrode in the present embodiment”, and the existing electrode that has been repaired again in the above step (A) is referred to as a “new electrode in the present embodiment”. Electrode ".
In the present embodiment, an electrolytic cell provided with an existing electrode is referred to as an “existing electrolytic cell”, and an electrolytic cell provided with a new electrode is referred to as a “new electrolytic cell”. That is, the existing electrolytic cell is assumed to be “an electrolytic cell that has already been operated”, and the new electrolytic cell is assumed to be “an electrolytic cell that has not been operated yet”. Here, once the electrolytic cell manufactured as a new electrolytic cell is put into operation, it becomes “the existing electrolytic cell in the present embodiment”, and the existing electrode in this existing electrolytic cell repaired by the above-described step (A) is This is a “new electrolytic cell in the present embodiment”.
In the present embodiment, "repair" is to improve the electrolytic performance of the existing electrode, to make the performance equivalent to the initial performance that the electrode had before being provided for operation, or from the initial performance Also means high performance.

(Step (A))
In the step (A) in the present embodiment, an electrode for electrolysis having a thickness of 315 μm or less is fixed to at least one region of the surface of the existing electrode. The surface of the existing electrode is not particularly limited, but is preferably a surface facing the diaphragm of the existing electrode from the viewpoint of effectively preventing damage to the diaphragm. That is, it is preferable to fix the electrode for electrolysis in the present embodiment to at least one region on the diaphragm-facing surface of the existing electrode. In the present embodiment, various means can be adopted as the “fixed” means. Specific examples of suitable fixing means will be described later.

  In the step (A), before fixing the electrode for electrolysis, a step of identifying a deteriorated portion of the existing electrode and cutting off the deteriorated portion can be included. The deteriorated portion can be easily removed by, for example, precision scissors or the like. Instead of such a resection, or as a post-resection process, a process of folding or crushing a sharp portion that damages the diaphragm so as not to face the diaphragm may be performed.

  In the present embodiment, from the viewpoint of preventing the stagnation of the electrolytic solution, the electrode thickness (the thickness obtained by adding the thickness of the electrode for electrolysis to the thickness of the existing electrode) is not excessively increased at the stage after the step (A). preferable. Specifically, it is preferable that the ratio of the electrode thickness T1 of the existing electrode before repair to the electrode thickness T2 after repair is 1.0 / 2.1 or less as T2 / T1. In addition, from the viewpoint of further preventing the stagnation of the electrolytic solution, it is more preferably more than 1.0 and not more than 1.67, further preferably not less than 1.00 and not more than 1.67, and still more preferably not more than 1.01. Or more and 1.50 or less, more preferably 1.02 or more and 1.34 or less.

(Electrode electrode)
The electrode for electrolysis in the present embodiment is an electrode used for electrolysis, and is not particularly limited as long as the thickness is 315 μm or less. In addition, the electrode for electrolysis in the present embodiment functions as an anode when the existing electrode is an anode, and functions as a cathode when the existing electrode is a cathode.

The electrode for electrolysis in the present embodiment has good handling properties, and has good adhesive strength with a diaphragm such as an ion exchange membrane or a microporous membrane, a power supply (a deteriorated electrode and an electrode not coated with a catalyst), and the like. From the viewpoint of having, the applied force per unit mass / unit area is preferably 1.6 N / (mg · cm ² ) or less, more preferably less than 1.6 N / (mg · cm ² ), and It is preferably less than 1.5 N / (mg · cm ² ), more preferably 1.2 N / mg · cm ² or less, and even more preferably 1.20 N / mg · cm ² or less. Even more preferably not more than 1.1N / mg · cm ^2, even more preferably not more than 1.10N / mg · cm ^2, particularly preferably at 1.0N / mg · cm ² or less, 1.00 N / Mg · cm ² or less is particularly preferred.
From the viewpoint of improving the electrolysis performance, preferably 0.005N / (mg · cm ²⁾ greater, more preferably 0.08N / (mg · cm ²⁾ or more, more preferably 0.1 N / mg Cm ² or more, and more preferably 0.14 N / (mg · cm ² ) or more. From the viewpoint that handling in a large size (for example, a size of 1.5 m × 2.5 m) becomes easy, 0.2 N / (mg · cm ² ) or more is still more preferable.
The above-mentioned force can be set in the above-mentioned range by appropriately adjusting, for example, the porosity, the electrode thickness, and the arithmetic average surface roughness described later. More specifically, for example, when the aperture ratio is increased, the force tends to decrease, and when the aperture ratio is decreased, the force tends to increase.
In addition, good handling properties are obtained, and it has good adhesive strength with a diaphragm such as an ion exchange membrane or a microporous membrane, a deteriorated electrode and a power feeder that is not coated with a catalyst, and further, from the viewpoint of economy. The mass per unit area is preferably 48 mg / cm ² or less, more preferably 30 mg / cm ² or less, further preferably 20 mg / cm ² or less. From a comprehensive point of view combining the cost and the economical efficiency, it is 15 mg / cm ² or less. The lower limit is not particularly limited, but is, for example, about 1 mg / cm ² .
The mass per unit area can be set in the above range by appropriately adjusting the porosity, the thickness of the electrode, and the like, which will be described later. More specifically, for example, if the thickness is the same, when the porosity is increased, the mass per unit area tends to decrease, and when the porosity is reduced, the mass per unit area tends to increase. is there.

Such a force can be measured by the following method (i) or (ii). The value obtained by the measurement of the method (i) (also referred to as “the force (1)”) and the value obtained by the measurement of the method (ii) are obtained. Value (also referred to as “the applied force (2)”) may be the same or different, but any value is less than 1.5 N / mg · cm ^2. Is preferred.

[Method (i)]
Inorganic particles and a binder were applied to both surfaces of a nickel plate (thickness: 1.2 mm, 200 mm square) obtained by blasting with alumina having a grain number of 320 and a film of a perfluorocarbon polymer into which ion-exchange groups had been introduced. An ion-exchange membrane (170 mm square) and an electrode sample (130 mm square) are laminated in this order, and the laminated body is sufficiently immersed in pure water to remove excess water adhering to the surface of the laminated body. Obtain a sample for measurement. The arithmetic average surface roughness (Ra) of the blasted nickel plate is 0.5 to 0.8 μm. The specific method of calculating the arithmetic average surface roughness (Ra) is as described in the examples.
Under the conditions of a temperature of 23 ± 2 ° C. and a relative humidity of 30 ± 5%, only the electrode sample in the measurement sample was vertically raised at a rate of 10 mm / min using a tensile compression tester, and the electrode sample was Measure the load when rising 10 mm in the vertical direction. This measurement is performed three times to calculate an average value.
The average value is divided by the area of the overlapping portion between the electrode sample and the ion exchange membrane and the mass of the overlapping portion of the ion exchange membrane in the electrode sample, and the force per unit mass / unit area (1) (N / Mg · cm ² ).

The force (1) applied per unit mass / unit area obtained by the method (i) provides good handling properties, and has a membrane such as an ion exchange membrane or a microporous membrane, a deteriorated electrode and a catalyst coating. From the viewpoint of having a good adhesive strength with no power feeder, it is preferably 1.6 N / (mg · cm ² ) or less, more preferably less than 1.6 N / (mg · cm ² ), and It is preferably less than 1.5 N / (mg · cm ² ), more preferably 1.2 N / mg · cm ² or less, and even more preferably 1.20 N / mg · cm ² or less. Even more preferably not more than 1.1N / mg · cm ^2, even more preferably not more than 1.10N / mg · cm ^2, particularly preferably at 1.0N / mg · cm ² or less, 1.00 N / Mg · cm ² or less is particularly preferred. From the viewpoint of further improving electrolytic performance, preferably 0.005N / (mg · cm ²⁾ greater, more preferably 0.08N / (mg · cm ²⁾ or more, more preferably, 0. 1 N / (mg · cm ² ) or more, and further preferably 0.14 N / (mg) from the viewpoint that handling in a large size (for example, a size of 1.5 m × 2.5 m) becomes easy. .Cm ² ), and more preferably 0.2 N / (mg · cm ² ) or more.

[Method (ii)]
A nickel plate (thickness 1.2 mm, 200 mm square, nickel plate similar to the method (i)) obtained by blasting with alumina having a grain number of 320 and an electrode sample (130 mm square) are laminated in this order. After sufficiently immersing the laminate in pure water, a sample for measurement is obtained by removing excess water attached to the surface of the laminate. Under the conditions of a temperature of 23 ± 2 ° C. and a relative humidity of 30 ± 5%, only the electrode sample in the measurement sample was vertically moved at a rate of 10 mm / min using a tensile compression tester, and the electrode sample was , And the weight when rising by 10 mm in the vertical direction is measured. This measurement is performed three times to calculate an average value.
This average value was divided by the area of the overlapping portion between the electrode sample and the nickel plate and the mass of the electrode sample in the portion overlapping with the nickel plate to obtain the adhesive force per unit mass / unit area (2) (N / mg・ Calculate cm ² ).

The force (2) applied per unit mass and unit area, obtained by the method (ii), provides good handling properties, and has a membrane such as an ion exchange membrane or a microporous membrane, a deteriorated electrode and a catalyst coating. From the viewpoint of having good adhesive strength with no power feeder, it is preferably 1.6 N / (mg · cm ² ) or less, more preferably less than 1.6 N / (mg · cm ² ), and It is preferably less than 1.5 N / (mg · cm ² ), still more preferably 1.2 N / mg · cm ² or less, and even more preferably 1.20 N / mg · cm ² or less. Even more preferably not more than 1.1N / mg · cm ^2, even more preferably not more than 1.10N / mg · cm ^2, particularly preferably at 1.0N / mg · cm ² or less, 1.00 N / Mg · cm ² or less is particularly preferred. Furthermore, from the standpoint of further improving electrolytic performance, preferably 0.005N / (mg · cm ²⁾ greater, more preferably 0.08N / (mg · cm ²⁾ or more, more preferably, 0. 1 N / (mg · cm ² ) or more, more preferably still more preferably 0.1 from the viewpoint that handling in a large size (for example, size 1.5 m × 2.5 m) becomes easy. 14 N / (mg · cm ² ) or more.

Although the electrode for electrolysis in the present embodiment is not particularly limited, good handleability is obtained, and a diaphragm such as an ion exchange membrane or a microporous membrane, a deteriorated electrode (feeder), and an electrode not coated with a catalyst (feeder). From the viewpoint of having good adhesive strength with the (body), the ratio measured by the following method (2) is preferably 90% or more, more preferably 92% or more, and further, a large size ( For example, from the viewpoint of easy handling at a size of 1.5 m × 2.5 m), it is more preferably 95% or more. The upper limit is 100%.
[Method (2)]
An ion exchange membrane (170 mm square) and an electrode sample (130 mm square) are laminated in this order. Under a condition of a temperature of 23 ± 2 ° C. and a relative humidity of 30 ± 5%, the laminate is placed on a curved surface of a polyethylene pipe (outer diameter: 280 mm) such that the electrode sample in the laminate is on the outside. And the pipe are sufficiently immersed in pure water to remove excess water adhering to the surface of the laminate and the pipe, and one minute later, a portion where the ion exchange membrane (170 mm square) and the electrode sample are in close contact. The ratio (%) of the area of is measured.

Although the electrode for electrolysis in the present embodiment is not particularly limited, good handling properties can be obtained, and a diaphragm such as an ion exchange membrane or a microporous membrane, a deteriorated electrode (feeder) and an electrode not coated with a catalyst (feeder). From the viewpoint that it has good adhesive strength to the body) and can be suitably wound into a roll and can be folded well, the ratio measured by the following method (3) is preferably 75% or more, It is more preferably at least 80%, and even more preferably at least 90%, from the viewpoint that handling in a large size (for example, size of 1.5 m × 2.5 m) becomes easy. The upper limit is 100%.
[Method (3)]
An ion exchange membrane (170 mm square) and an electrode sample (130 mm square) are laminated in this order. Under a condition of a temperature of 23 ± 2 ° C. and a relative humidity of 30 ± 5%, the laminate is placed on a curved surface of a polyethylene pipe (outer diameter: 145 mm) so that the electrode sample in the laminate is outside, and the laminate is formed. And the pipe are sufficiently immersed in pure water to remove excess water adhering to the surface of the laminate and the pipe. One minute later, the portion where the ion exchange membrane (170 mm square) and the electrode sample are in close contact with each other. The ratio (%) of the area of is measured.

Although the electrode for electrolysis in the present embodiment is not particularly limited, good handling properties can be obtained, and a diaphragm such as an ion exchange membrane or a microporous membrane, a deteriorated electrode (feeder) and an electrode not coated with a catalyst (feeder). From the viewpoint of preventing the gas generated during electrolysis from staying, the porous structure is preferable, and the porosity or porosity thereof is preferably 5 to 90% or less. The porosity is more preferably 10 to 80% or less, and further preferably 20 to 75%.
The porosity is the ratio of the porosity per unit volume. There are various calculation methods depending on whether the opening is also considered to the submicron order or only the visible opening. In the present embodiment, the volume V is calculated from the values of the gauge thickness, width, and length of the electrode, and the weight W is actually measured to calculate the porosity A by the following equation.
A = (1− (W / (V × ρ)) × 100
ρ is the density (g / cm ³ ) of the electrode material. For example, nickel is 8.908 g / cm ³ and titanium is 4.506 g / cm ³ . To adjust the aperture ratio, change the area of punching metal per unit area in the case of punching metal, change the value of SW (shorter diameter), LW (longer diameter), and feed in the case of expanded metal. Changes the wire diameter and mesh number of metal fibers, changes the pattern of the photoresist used for electroforming, changes the metal fiber diameter and fiber density for nonwoven fabrics, and forms voids for foamed metal It can be adjusted as appropriate by a method such as changing a mold to be used.

Hereinafter, one form of the electrode for electrolysis in the present embodiment will be described.
The electrode for electrolysis according to the present embodiment preferably includes an electrode substrate for electrolysis and a catalyst layer. As described below, the catalyst layer may be composed of a plurality of layers or may have a single-layer structure.
As shown in FIG. 1, the electrode for electrolysis 100 according to the present embodiment includes an electrode base for electrolysis 10 and a pair of first layers 20 covering both surfaces of the electrode base for electrolysis 10. The first layer 20 preferably covers the entire electrode base 10 for electrolysis. Thereby, the catalytic activity and durability of the electrode for electrolysis are easily improved. The first layer 20 may be laminated only on one surface of the electrode substrate 10 for electrolysis.
Further, as shown in FIG. 1, the surface of the first layer 20 may be covered with the second layer 30. The second layer 30 preferably covers the entire first layer 20. Further, the second layer 30 may be laminated only on one surface of the first layer 20.

(Electrode electrode substrate)
The electrode substrate 10 for electrolysis is not particularly limited. For example, a valve metal typified by nickel, nickel alloy, stainless steel, titanium or the like can be used, and nickel (Ni) and titanium (Ti) are used. It preferably contains at least one selected element.
When stainless steel is used in a high-concentration alkaline aqueous solution, considering that iron and chromium are eluted and that the electrical conductivity of stainless steel is about 1/10 of nickel, A substrate containing nickel (Ni) is preferred.
When the electrode substrate 10 for electrolysis is used in a chlorine gas generating atmosphere in a saline solution having a high concentration close to saturation, it is also preferable that the material is titanium having high corrosion resistance.
The shape of the electrode substrate for electrolysis 10 is not particularly limited, and an appropriate shape can be selected depending on the purpose. As the shape, any of a punched metal, a nonwoven fabric, a foamed metal, an expanded metal, a porous metal foil formed by electroforming, and a so-called woven mesh formed by knitting a metal wire can be used. Among them, a punching metal or an expanded metal is preferable. Note that electroforming is a technique for producing a metal thin film with a precise pattern by combining photolithography and electroplating. In this method, a pattern is formed on a substrate with a photoresist, and electroplating is performed on a portion not protected by the resist to obtain a thin metal.
Regarding the shape of the electrode substrate for electrolysis, there are preferable specifications depending on the distance between the anode and the cathode in the electrolytic cell. Although not particularly limited, when the anode and the cathode have a finite distance, expanded metal and punched metal shapes can be used. For example, a woven mesh, a wire mesh, a foamed metal, a metal nonwoven fabric, an expanded metal, a punching metal, a metal porous foil, or the like can be used.
Examples of the electrode substrate for electrolysis 10 include a metal porous foil, a wire mesh, a metal nonwoven fabric, a punching metal, an expanded metal, and a foamed metal. That is, the electrode for electrolysis preferably has a punched shape, an expanded shape, or a mesh shape.
As a plate material before being processed into a punching metal or an expanded metal, a roll-formed plate material, an electrolytic foil, or the like is preferable. It is preferable that the electrolytic foil is further subjected to a plating treatment with the same element as that of the base material as a post-treatment, so that one side or both sides are provided with irregularities.
In addition, the thickness of the electrode substrate for electrolysis 10 is preferably less than 315 μm, more preferably 300 μm or less, more preferably 205 μm or less, further preferably 155 μm or less, and more preferably 135 μm or less. Is still more preferably 125 μm or less, still more preferably 120 μm or less, even more preferably 100 μm or less, and from the viewpoint of handling and economy, it is 50 μm or less. Is even more preferred. The lower limit is not particularly limited, but is, for example, 1 μm, preferably 5 μm, and more preferably 15 μm.

  In the electrode substrate for electrolysis, it is preferable that the electrode substrate for electrolysis is annealed in an oxidizing atmosphere to reduce residual stress during processing. Further, on the surface of the electrode substrate for electrolysis, in order to improve the adhesion with the catalyst layer coated on the surface, irregularities are formed using a steel grid, alumina powder, or the like, and then the surface area is increased by an acid treatment. Preferably, it is increased. Alternatively, it is preferable to increase the surface area by performing plating with the same element as the base material.

  The electrode substrate 10 for electrolysis is preferably subjected to a treatment for increasing the surface area in order to make the first layer 20 and the surface of the electrode substrate 10 for electrolysis adhere to each other. Examples of the treatment for increasing the surface area include a blast treatment using a cut wire, a steel grid, an alumina grid, or the like, an acid treatment using sulfuric acid or hydrochloric acid, and a plating treatment using the same element as the base material. The arithmetic average surface roughness (Ra) of the substrate surface is not particularly limited, but is preferably 0.05 μm to 50 μm, more preferably 0.1 μm to 10 μm, and still more preferably 0.1 μm to 8 μm.

Next, the case where the electrode for electrolysis in this embodiment is used as an anode for salt electrolysis will be described.
(First layer)
In FIG. 1, the first layer 20, which is a catalyst layer, contains at least one oxide of ruthenium oxide, iridium oxide, and titanium oxide. As the ruthenium oxide, RuO _{2 and the} like can be mentioned. Examples of the iridium oxide include IrO ₂ . Examples of the titanium oxide include TiO _{2 and the} like. The first layer 20 preferably contains two kinds of oxides of ruthenium oxide and titanium oxide, or contains three kinds of oxides of ruthenium oxide, iridium oxide and titanium oxide. Thereby, the first layer 20 becomes a more stable layer, and the adhesion to the second layer 30 is further improved.

  In the case where the first layer 20 contains two kinds of oxides, ruthenium oxide and titanium oxide, the titanium oxide contained in the first layer 20 is contained in one mole of the ruthenium oxide contained in the first layer 20. The amount of the compound is preferably 1 to 9 mol, more preferably 1 to 4 mol. By setting the composition ratio of the two oxides in this range, the electrode for electrolysis 100 exhibits excellent durability.

  When the first layer 20 contains three kinds of oxides of ruthenium oxide, iridium oxide and titanium oxide, the first layer 20 is contained in the first layer 20 with respect to 1 mol of the ruthenium oxide contained in the first layer 20. The amount of the iridium oxide is preferably from 0.2 to 3 mol, more preferably from 0.3 to 2.5 mol. Further, the titanium oxide contained in the first layer 20 is preferably 0.3 to 8 mol, more preferably 1 to 7 mol, based on 1 mol of the ruthenium oxide contained in the first layer 20. preferable. By setting the composition ratio of the three oxides in this range, the electrode for electrolysis 100 exhibits excellent durability.

  When the first layer 20 contains at least two kinds of oxides selected from ruthenium oxide, iridium oxide and titanium oxide, it is preferable that these oxides form a solid solution. By forming an oxide solid solution, the electrode for electrolysis 100 exhibits excellent durability.

  In addition to the above compositions, various compositions can be used as long as they contain at least one oxide of ruthenium oxide, iridium oxide, and titanium oxide. For example, an oxide coating containing ruthenium, iridium, tantalum, niobium, titanium, tin, cobalt, manganese, platinum, or the like, which is called DSA (registered trademark), can be used as the first layer 20.

  The first layer 20 does not need to be a single layer and may include a plurality of layers. For example, the first layer 20 may include a layer containing three kinds of oxides and a layer containing two kinds of oxides. The thickness of the first layer 20 is preferably from 0.05 to 10 μm, more preferably from 0.1 to 8 μm.

(Second layer)
The second layer 30 preferably contains ruthenium and titanium. Thereby, the chlorine overvoltage immediately after electrolysis can be further reduced.

  The second layer 30 preferably contains palladium oxide, a solid solution of palladium oxide and platinum, or an alloy of palladium and platinum. Thereby, the chlorine overvoltage immediately after electrolysis can be further reduced.

  Although the longer the second layer 30 is, the longer the period in which the electrolytic performance can be maintained, the thickness is preferably 0.05 to 3 μm from the viewpoint of economy.

Next, the case where the electrode for electrolysis in this embodiment is used as a cathode for salt electrolysis will be described.
(First layer)
The components of the first layer 20 that is the catalyst layer include C, Si, P, S, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, and Ru. , Rh, Pd, Ag, Cd, In, Sn, Ta, W, Re, Os, Ir, Pt, Au, Hg, Pb, Bi, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb , Dy, Ho, Er, Tm, Yb, Lu and the like, and oxides or hydroxides of such metals.
It may or may not include at least one of platinum group metals, platinum group metal oxides, platinum group metal hydroxides, and alloys containing platinum group metals.
When at least one of a platinum group metal, a platinum group metal oxide, a platinum group metal hydroxide, and an alloy containing a platinum group metal is contained, a platinum group metal, a platinum group metal oxide, a platinum group metal hydroxide, a platinum group metal It is preferable that the alloy containing a metal contains at least one platinum group metal among platinum, palladium, rhodium, ruthenium, and iridium.
The platinum group metal preferably contains platinum.
The platinum group metal oxide preferably contains ruthenium oxide.
The platinum group metal hydroxide preferably contains a ruthenium hydroxide.
The platinum group metal alloy preferably includes an alloy of platinum with nickel, iron, and cobalt.
Further, it is preferable that the second component contains an oxide or hydroxide of a lanthanoid element as necessary. Thereby, the electrode 100 for electrolysis shows excellent durability.
The oxide or hydroxide of a lanthanoid element preferably contains at least one selected from lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, and dysprosium.
Further, if necessary, it is preferable to include a transition metal oxide or hydroxide as the third component.
By adding the third component, the electrode for electrolysis 100 shows more excellent durability, and the electrolysis voltage can be reduced.
Examples of preferred combinations include ruthenium only, ruthenium + nickel, ruthenium + cerium, ruthenium + lanthanum, ruthenium + lanthanum + platinum, ruthenium + lanthanum + palladium, ruthenium + praseodymium, ruthenium + praseodymium + platinum, ruthenium + praseodymium + platinum + Palladium, ruthenium + neodymium, ruthenium + neodymium + platinum, ruthenium + neodymium + manganese, ruthenium + neodymium + iron, ruthenium + neodymium + cobalt, ruthenium + neodymium + zinc, ruthenium + neodymium + gallium, ruthenium + neodymium + sulfur, ruthenium + Neodymium + lead, ruthenium + neodymium + nickel, ruthenium + neodymium + copper, ruthenium + samarium, ruthenium + samarium + manganese, ruthenium + summary Ruthenium + samarium + cobalt, ruthenium + samarium + zinc, ruthenium + samarium + gallium, ruthenium + samarium + sulfur, ruthenium + samarium + lead, ruthenium + samarium + nickel, platinum + cerium, platinum + palladium + cerium, Platinum + palladium + lanthanum + cerium, platinum + iridium, platinum + palladium, platinum + iridium + palladium, platinum + nickel + palladium, platinum + nickel + ruthenium, an alloy of platinum and nickel, an alloy of platinum and cobalt, platinum and iron Alloys and the like.
When a platinum group metal, a platinum group metal oxide, a platinum group metal hydroxide, or an alloy containing a platinum group metal is not contained, the main component of the catalyst is preferably a nickel element.
It is preferable to include at least one of nickel metal, oxide, and hydroxide.
As the second component, a transition metal may be added. The second component to be added preferably contains at least one element of titanium, tin, molybdenum, cobalt, manganese, iron, sulfur, zinc, copper, and carbon.
Preferred combinations include nickel + tin, nickel + titanium, nickel + molybdenum, nickel + cobalt, and the like.
If necessary, an intermediate layer can be provided between the first layer 20 and the electrode substrate 10 for electrolysis. By providing the intermediate layer, the durability of the electrode for electrolysis 100 can be improved.
The intermediate layer preferably has an affinity for both the first layer 20 and the electrode substrate 10 for electrolysis. As the intermediate layer, nickel oxide, platinum group metal, platinum group metal oxide, and platinum group metal hydroxide are preferable. The intermediate layer can be formed by applying and baking a solution containing a component for forming the intermediate layer, or performing a heat treatment on the base material at a temperature of 300 to 600 ° C. in an air atmosphere to perform surface oxidation. An object layer can also be formed. In addition, it can be formed by a known method such as a thermal spraying method or an ion plating method.

(Second layer)
The components of the first layer 30 that is the catalyst layer include C, Si, P, S, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, and Ru. , Rh, Pd, Ag, Cd, In, Sn, Ta, W, Re, Os, Ir, Pt, Au, Hg, Pb, Bi, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb , Dy, Ho, Er, Tm, Yb, Lu and the like, and oxides or hydroxides of such metals.
It may or may not include at least one of platinum group metals, platinum group metal oxides, platinum group metal hydroxides, and alloys containing platinum group metals. Examples of preferable combinations of the elements included in the second layer include the combinations described in the first layer. The combination of the first layer and the second layer may be a combination having the same composition but different composition ratios, or a combination of different compositions.
As the thickness of the catalyst layer, the total thickness of the formed catalyst layer and the intermediate layer is preferably 0.01 μm to 20 μm. When the thickness is 0.01 μm or more, a sufficient function as a catalyst can be exhibited. When the thickness is 20 μm or less, a strong catalyst layer can be formed with less falling off from the substrate. 0.05 μm to 15 μm is more preferable. More preferably, it is 0.1 μm to 10 μm. More preferably, it is 0.2 μm to 8 μm.

  As the thickness of the electrode, that is, the total thickness of the electrode substrate for electrolysis and the catalyst layer, it is possible to prevent an excessive increase in the electrode thickness of the repaired portion, and to prevent pressing of the electrode from the electrode to the diaphragm and stagnation of the electrolyte in that portion. From the viewpoint which can be performed, it is 315 micrometers or less, 220 micrometers or less are preferred, 170 micrometers or less are more preferred, 150 micrometers or less are still more preferred, 145 micrometers or less are still more preferred, 140 micrometers or less are still more preferred, 138 micrometers or less are still more preferred, and 135 micrometers or less are further preferred. More preferred. If it is 135 μm or less, good handling properties tend to be obtained. Further, from the same viewpoint as above, it is preferably 130 μm or less, more preferably less than 130 μm, further preferably 115 μm or less, and still more preferably 65 μm or less. The lower limit is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, and more preferably 20 μm or more from a practical standpoint. The thickness of the electrode can be determined by measuring with a Digimatic Sixness Gauge (Mitutoyo Co., Ltd., minimum display 0.001 mm). The thickness of the electrode substrate is measured in the same manner as the electrode thickness. The thickness of the catalyst layer can be determined by subtracting the thickness of the electrode substrate for electrolysis from the electrode thickness.

  In the present embodiment, from the viewpoint of ensuring sufficient electrolytic performance, the electrode for electrolysis is composed of Ru, Rh, Pd, Ir, Pt, Au, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ag, Ta, W, Re, Os, Al, In, Sn, Sb, Ga, Ge, B, C, N, O, Si, P, S, La, Ce, Pr, It is preferable to include at least one catalyst component selected from the group consisting of Nd, Pm, Sm, Eu, Gd, Tb and Dy.

  In the present embodiment, the thickness of the electrode for electrolysis is 315 μm or less from the viewpoint that it is possible to prevent an excessive increase in the electrode thickness of the repaired portion and to prevent pressing of the electrode from the electrode to the diaphragm and stagnation of the electrolyte in that portion. 220 μm or less is preferred, 170 μm or less is more preferred, 150 μm or less is even more preferred, 145 μm or less is even more preferred, 140 μm or less is even more preferred, 138 μm or less is even more preferred, and 135 μm or less is even more preferred. If it is 135 μm or less, good handling properties tend to be obtained. Further, from the same viewpoint as described above, it is preferably 130 μm or less, more preferably less than 130 μm, further preferably 115 μm or less, and still more preferably 65 μm or less. The lower limit is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, and more preferably 20 μm or more from a practical standpoint. The electrode for electrolysis having the above-described thickness can be said to be an electrode having a wide elastic deformation region, and has better handling properties, a diaphragm such as an ion exchange membrane or a microporous membrane, a deteriorated electrode, and a catalyst coating. This is preferable from the viewpoint of having a better adhesive strength with a power supply body or the like that is not subjected to the above-described process. In the present embodiment, “the elastic deformation region is wide” means that the electrode for electrolysis is wound to form a wound body, and after the wound state is released, the warpage due to the winding is hardly generated. . The thickness of the electrode for electrolysis, when including a catalyst layer described later, refers to the total thickness of the electrode substrate for electrolysis and the catalyst layer.

(Method of manufacturing electrode for electrolysis)
Next, an embodiment of a method for manufacturing the electrode for electrolysis 100 will be described in detail.
In the present embodiment, the first layer 20, preferably the second layer, is formed on the electrode substrate for electrolysis by a method such as baking (thermal decomposition) of the coating film in an oxygen atmosphere, or ion plating, plating, or thermal spraying. By forming 30, the electrode 100 for electrolysis can be manufactured. According to such a manufacturing method of the present embodiment, high productivity of the electrode for electrolysis 100 can be realized. Specifically, a catalyst layer is formed on the electrode substrate for electrolysis by a coating step of coating a coating liquid containing a catalyst, a drying step of drying the coating liquid, and a pyrolysis step of thermal decomposition. Here, the term "thermal decomposition" means that a metal salt as a precursor is heated and decomposed into a metal or metal oxide and a gaseous substance. Decomposition products vary depending on the type of metal used, the type of salt, the atmosphere in which thermal decomposition is performed, and the like. However, many metals tend to form oxides in an oxidizing atmosphere. In the industrial manufacturing process of electrodes, pyrolysis is usually carried out in air, often forming metal oxides or hydroxides.

(Formation of the first layer of the anode)
(Coating process)
The first layer 20 is formed by applying a solution (first coating solution) in which at least one metal salt of ruthenium, iridium and titanium is dissolved to an electrode substrate for electrolysis, and then thermally decomposing (firing) in the presence of oxygen. Obtained. The contents of ruthenium, iridium and titanium in the first coating solution are substantially equal to those of the first layer 20.

  The metal salt may be in the form of chloride, nitrate, sulfate, metal alkoxide, or any other form. The solvent of the first coating solution can be selected according to the type of the metal salt, but water and alcohols such as butanol can be used. As the solvent, water or a mixed solvent of water and an alcohol is preferable. The total metal concentration in the first coating solution in which the metal salt is dissolved is not particularly limited, but is preferably in the range of 10 to 150 g / L in consideration of the thickness of the coating film formed by one application.

  Examples of the method of applying the first coating solution on the electrode substrate for electrolysis 10 include a dipping method in which the electrode substrate 10 for electrolysis is dipped in the first coating solution, a method of applying the first coating solution with a brush, and a method of applying the first coating solution. A roll method using a sponge-like roll impregnated with a liquid, an electrostatic coating method in which the electrode substrate for electrolysis 10 and the first coating liquid are charged to opposite charges and sprayed are used. Among them, the roll method or the electrostatic coating method, which is excellent in industrial productivity, is preferable.

(Drying process, thermal decomposition process)
After applying the first coating solution to the electrode substrate 100 for electrolysis, the coating solution is dried at a temperature of 10 to 90 ° C. and thermally decomposed in a firing furnace heated to 350 to 650 ° C. Preliminary calcination may be performed at 100 to 350 ° C. between drying and thermal decomposition as needed. Drying, calcination and thermal decomposition temperatures can be appropriately selected depending on the composition of the first coating solution and the type of solvent. The longer the time of thermal decomposition per cycle is, the more preferable it is, but from the viewpoint of electrode productivity, it is preferably 3 to 60 minutes, more preferably 5 to 20 minutes.

  By repeating the above-described cycle of application, drying and thermal decomposition, the coating (first layer 20) is formed to a predetermined thickness. After the first layer 20 is formed, if necessary, after baking for a longer time, heating is performed to further enhance the stability of the first layer 20.

(Formation of the second layer)
The second layer 30 is formed as necessary. For example, after applying a solution containing a palladium compound and a platinum compound or a solution containing a ruthenium compound and a titanium compound (second coating solution) on the first layer 20, Obtained by pyrolysis in the presence of oxygen.

(Formation of the first layer of the cathode by pyrolysis)
(Coating process)
The first layer 20 is obtained by applying a solution (first coating solution) in which various combinations of metal salts are dissolved to an electrode substrate for electrolysis, and then thermally decomposing (firing) in the presence of oxygen. The metal content in the first coating solution is substantially equal to that of the first layer 20.

  The metal salt may be in the form of chloride, nitrate, sulfate, metal alkoxide, or any other form. The solvent of the first coating solution can be selected according to the type of the metal salt, but water and alcohols such as butanol can be used. As the solvent, water or a mixed solvent of water and an alcohol is preferable. The total metal concentration in the first coating solution in which the metal salt is dissolved is not particularly limited, but is preferably in the range of 10 to 150 g / L in consideration of the thickness of the coating film formed by one application.

  Examples of the method of applying the first coating solution on the electrode substrate for electrolysis 10 include a dipping method in which the electrode substrate 10 for electrolysis is dipped in the first coating solution, a method of applying the first coating solution with a brush, and a method of applying the first coating solution. A roll method using a sponge-like roll impregnated with a liquid, an electrostatic coating method in which the electrode substrate for electrolysis 10 and the first coating liquid are charged to opposite charges and sprayed are used. Among them, the roll method or the electrostatic coating method, which is excellent in industrial productivity, is preferable.

(Drying process, thermal decomposition process)
After applying the first coating solution to the electrode substrate 10 for electrolysis, the coating solution is dried at a temperature of 10 to 90 ° C. and thermally decomposed in a firing furnace heated to 350 to 650 ° C. Preliminary calcination may be performed at 100 to 350 ° C. between drying and thermal decomposition as needed. Drying, calcination and thermal decomposition temperatures can be appropriately selected depending on the composition of the first coating solution and the type of solvent. The longer the time of thermal decomposition per cycle is, the more preferable it is, but from the viewpoint of electrode productivity, it is preferably 3 to 60 minutes, more preferably 5 to 20 minutes.

  By repeating the above-described cycle of application, drying and thermal decomposition, the coating (first layer 20) is formed to a predetermined thickness. After the first layer 20 is formed, if necessary, after baking for a longer time, heating is performed to further enhance the stability of the first layer 20.

(Formation of intermediate layer)
The intermediate layer is formed as necessary. For example, the intermediate layer is obtained by applying a solution containing a palladium compound or a platinum compound (second coating solution) on a substrate, and then thermally decomposing the substrate in the presence of oxygen. Alternatively, the nickel oxide intermediate layer may be formed on the surface of the substrate only by heating the substrate without applying the solution.

(Formation of the first layer of the cathode by ion plating)
The first layer 20 can also be formed by ion plating.
As an example, there is a method in which a substrate is fixed in a chamber and an electron beam is irradiated on a metal ruthenium target. The evaporated metal ruthenium particles are positively charged in the plasma in the chamber and are deposited on the negatively charged substrate. The plasma atmosphere is argon and oxygen, and ruthenium is deposited on the substrate as ruthenium oxide.

(Formation of the first layer of the cathode by plating)
The first layer 20 can also be formed by a plating method.
As an example, when the substrate is used as a cathode and the electrolytic plating is performed in an electrolytic solution containing nickel and tin, an alloy plating of nickel and tin can be formed.

(Formation of the first layer of the cathode by thermal spraying)
The first layer 20 can also be formed by a thermal spray method.
As an example, a catalyst layer in which nickel metal and nickel oxide are mixed can be formed by plasma spraying nickel oxide particles on a substrate.

  The electrode for electrolysis in this embodiment forms a new electrode together with the existing electrode through the step (A). When a new electrode is placed in the electrolytic cell, the electrode for electrolysis is adjacent to a diaphragm such as an ion exchange membrane or a microporous membrane. In this state, since the thickness of the electrode for electrolysis is 315 μm or less, the pressure on the diaphragm by the portion is reduced, and as a result, the stagnation of the electrolytic solution can be prevented.

Hereinafter, the ion exchange membrane will be described in detail.
(Ion exchange membrane)
The ion exchange membrane is not particularly limited, and various ion exchange membranes can be applied. In the present embodiment, an ion exchange membrane having a membrane main body containing a hydrocarbon polymer or a fluorinated polymer having an ion exchange group, and a coating layer provided on at least one surface of the membrane main body is used. Is preferred. Further, the coating layer contains inorganic particles and a binder, and the specific surface area of the coating layer is preferably 0.1 to 10 m ² / g. The ion exchange membrane having such a structure has little influence on the electrolysis performance due to gas generated during electrolysis, and tends to exhibit stable electrolysis performance.
Above, and the membrane of perfluorocarbon polymer ion exchange group is introduced, the ion-exchange groups derived from sulfo group - sulfonic acid having a (-SO ₃ groups represented by, hereinafter referred to as "sulfonic acid group".) And a carboxylic acid layer having an ion exchange group derived from a carboxyl group (a group represented by —CO ₂ —, hereinafter also referred to as a “carboxylic acid group”). From the viewpoint of strength and dimensional stability, it is preferable to further include a reinforced core material.
The inorganic particles and the binder will be described below in detail in the section of the description of the coating layer.

  FIG. 2 is a schematic sectional view showing an embodiment of the ion exchange membrane. The ion exchange membrane 1 has a membrane main body 1a containing a hydrocarbon polymer or a fluorinated polymer having an ion exchange group, and coating layers 11a and 11b formed on both surfaces of the membrane main body 1a.

In the ion-exchange membrane 1, the film body 1a is sulfo group derived from an ion-exchange group (-SO ₃ ^-. Groups represented by, hereinafter referred to as "sulfonic acid group") and a sulfonic acid layer 3 having the derived carboxyl group And a carboxylic acid layer 2 having an ion exchange group (a group represented by —CO ₂ ^— , hereinafter also referred to as a “carboxylic acid group”), and the strength and dimensional stability are enhanced by the reinforcing core material 4. . Since the ion exchange membrane 1 includes the sulfonic acid layer 3 and the carboxylic acid layer 2, it is preferably used as a cation exchange membrane.

  The ion exchange membrane may have only one of the sulfonic acid layer and the carboxylic acid layer. Further, the ion exchange membrane does not necessarily have to be reinforced by the reinforcing core material, and the arrangement state of the reinforcing core material is not limited to the example of FIG.

(Membrane body)
First, the membrane main body 1a constituting the ion exchange membrane 1 will be described.
The membrane body 1a has a function of selectively permeating cations, and may include a hydrocarbon-based polymer or a fluorinated polymer having an ion-exchange group, and its structure and material are not particularly limited. Instead, a suitable one can be appropriately selected.

  The hydrocarbon-based polymer or the fluorinated polymer having an ion-exchange group in the membrane main body 1a is, for example, a hydrocarbon-based polymer or a fluorinated polymer having an ion-exchange group precursor that can become an ion-exchange group by hydrolysis or the like. Can be obtained from coalescence. Specifically, for example, the main chain is made of a fluorinated hydrocarbon, has a group (ion-exchange group precursor) that can be converted to an ion-exchange group by hydrolysis or the like as a pendant side chain, and is melt-processable. After preparing a precursor of the membrane main body 1a using a polymer (hereinafter, sometimes referred to as “fluorinated polymer (a)”), the membrane is converted by converting the ion exchange group precursor into an ion exchange group. The main body 1a can be obtained.

  The fluorinated polymer (a) includes, for example, at least one monomer selected from the following first group and at least one monomer selected from the following second group and / or the third group: It can be produced by copolymerization. Further, it can also be produced by homopolymerization of one monomer selected from any of the following first group, second group, and third group.

  Examples of the first group of monomers include vinyl fluoride compounds. Examples of the vinyl fluoride compound include vinyl fluoride, tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, and perfluoroalkyl vinyl ether. In particular, when the ion exchange membrane is used as a membrane for alkaline electrolysis, the vinyl fluoride compound is preferably a perfluoro monomer, and is selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, and perfluoroalkyl vinyl ether. Fluoro monomers are preferred.

Examples of the second group of monomers include vinyl compounds having a functional group that can be converted into a carboxylic acid type ion exchange group (carboxylic acid group). Examples of the vinyl compound having a functional group that can be converted into a carboxylic acid group include a monomer represented by CF ₂ ＣＦCF (OCF ₂ CYF) _s —O (CZF) _t —COOR (here, a monomer). , S represents an integer of 0 to 2, t represents an integer of 1 to 12, Y and Z each independently represent F or CF ₃ , and R represents a lower alkyl group. For example, an alkyl group having 1 to 3 carbon atoms).

Among _{them, CF 2 = CF (OCF 2} CYF) n -O (CF 2) a compound represented by _m -COOR are preferred. Here, n represents an integer of 0 to 2, m represents an integer of 1 to 4, Y represents F or CF _3, R represents CH _3, C ₂ H _5, or C ₃ H _7.

  When the ion exchange membrane is used as a cation exchange membrane for alkaline electrolysis, it is preferable to use at least a perfluoro compound as a monomer, but the alkyl group of the ester group (see R above) becomes heavy at the time of hydrolysis. The alkyl group (R) does not have to be a perfluoroalkyl group in which all hydrogen atoms have been replaced by fluorine atoms, because it is lost from the coalescence.

Among the above-mentioned monomers of the second group, the following monomers are more preferable.
_{CF 2 = CFOCF 2 -CF (CF} 3) OCF 2 COOCH 3,
CF ₂ = CFOCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ COOCH ₃ ,
_{CF 2 = CF [OCF 2 -CF} (CF 3)] 2 O (CF 2) 2 COOCH 3,
CF ₂ = CFOCF ₂ CF (CF ₃ ) O (CF ₂ ) ₃ COOCH ₃ ,
CF ₂ ＣＦCFO (CF ₂ ) ₂ COOCH ₃ ,
_{CF 2 = CFO (CF 2)} 3 COOCH 3.

Examples of the third group of monomers include vinyl compounds having a functional group that can be converted into a sulfone ion exchange group (sulfonic acid group). The vinyl compound having a functional group that can be converted to sulfonic acid groups, e.g., CF ₂ = monomer represented by _{CFO-X-CF 2 -SO 2} F are preferred (wherein, X is perfluoroalkylene group .). Specific examples of these include the following monomers and the like.
CF ₂ = CFOCF ₂ CF ₂ SO ₂ F,
CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ SO ₂ F,
_{CF 2 = CFOCF 2 CF (CF} 3) OCF 2 CF 2 CF 2 SO 2 F,
CF ₂ = CF (CF ₂ ) ₂ SO ₂ F,
CF ₂ = CFO [CF ₂ CF (CF ₃ ) O] ₂ CF ₂ CF ₂ SO ₂ F,
_{CF 2 = CFOCF 2 CF (CF} 2 OCF 3) OCF 2 CF 2 SO 2 F.

Among them, CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ CF ₂ SO ₂ F and CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ SO ₂ F are more preferable.

  Copolymers obtained from these monomers can be produced by a polymerization method developed for homopolymerization and copolymerization of fluorinated ethylene, particularly a general polymerization method used for tetrafluoroethylene. . For example, in the non-aqueous method, an inert solvent such as perfluorohydrocarbon or chlorofluorocarbon is used in the presence of a radical polymerization initiator such as perfluorocarbon peroxide or azo compound, at a temperature of 0 to 200 ° C. and a pressure of 0 to 200 ° C. The polymerization reaction can be performed under the conditions of 1 to 20 MPa.

  In the above copolymerization, the type of the combination of the monomers and the ratio thereof are not particularly limited, and are selected and determined depending on the type and the amount of the functional group desired to be imparted to the obtained fluorine-containing polymer. For example, when a fluorinated polymer containing only a carboxylic acid group is used, at least one monomer may be selected from the first and second groups and copolymerized. In the case of a fluorinated polymer containing only a sulfonic acid group, at least one monomer may be selected from the first and third groups of monomers and copolymerized. Further, in the case of a fluorinated polymer having a carboxylic acid group and a sulfonic acid group, at least one monomer is selected from each of the monomers of the first, second, and third groups to form a copolymer. What is necessary is just to polymerize. In this case, the desired fluorine-containing system can also be obtained by separately polymerizing the copolymer consisting of the first group and the second group and the copolymer consisting of the first group and the third group and then mixing them. A polymer can be obtained. Further, the mixing ratio of each monomer is not particularly limited, but when increasing the amount of the functional group per unit polymer, if the ratio of the monomer selected from the second group and the third group is increased, Good.

  The total ion exchange capacity of the fluorinated copolymer is not particularly limited, but is preferably 0.5 to 2.0 mg equivalent / g, more preferably 0.6 to 1.5 mg equivalent / g. Here, the total ion exchange capacity refers to an equivalent of an exchange group per unit weight of the dry resin, and can be measured by neutralization titration or the like.

  In the membrane main body 1a of the ion exchange membrane 1, a sulfonic acid layer 3 containing a fluorinated polymer having a sulfonic acid group and a carboxylic acid layer 2 containing a fluorinated polymer having a carboxylic acid group are laminated. I have. With the membrane main body 1a having such a layer structure, the selective permeability of cations such as sodium ions can be further improved.

  When the ion exchange membrane 1 is disposed in the electrolytic cell, the sulfonic acid layer 3 is usually disposed on the anode side of the electrolytic cell, and the carboxylic acid layer 2 is disposed on the cathode side of the electrolytic cell.

  The sulfonic acid layer 3 is preferably made of a material having a low electric resistance, and is preferably thicker than the carboxylic acid layer 2 from the viewpoint of film strength. The film thickness of the sulfonic acid layer 3 is preferably 2 to 25 times, more preferably 3 to 15 times the carboxylic acid layer 2.

  It is preferable that the carboxylic acid layer 2 has high anion rejection even if the film thickness is small. The term “anion exclusion” as used herein refers to a property of preventing the anion from entering or permeating the ion exchange membrane 1. In order to increase the anion rejection, it is effective to provide a carboxylic acid layer having a small ion exchange capacity with respect to the sulfonic acid layer.

Examples of the fluorine-containing polymer used for the sulfonic acid layer 3 include a polymer obtained by using CF ₂ ＝ CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ SO ₂ F as a third group of monomers. It is suitable.

The fluorine-containing polymer used in the carboxylic acid layer 2, for example, the _{CF 2 = CFOCF 2 CF (CF} 2) a second group of monomers O (CF ₂₎ polymer obtained using ₂ COOCH ₃ Is preferred.

(Coating layer)
The ion exchange membrane preferably has a coating layer on at least one surface of the membrane main body. Further, as shown in FIG. 2, in the ion exchange membrane 1, coating layers 11a and 11b are formed on both surfaces of the membrane main body 1a, respectively.
The coating layer contains inorganic particles and a binder.

  The average particle size of the inorganic particles is more preferably 0.90 μm or more. When the average particle diameter of the inorganic particles is 0.90 μm or more, not only gas adhesion but also durability against impurities is extremely improved. That is, a particularly remarkable effect can be obtained by increasing the average particle size of the inorganic particles and satisfying the above-mentioned specific surface area. In order to satisfy such average particle size and specific surface area, irregular inorganic particles are preferable. Inorganic particles obtained by melting and inorganic particles obtained by grinding ore can be used. Preferably, inorganic particles obtained by crushing ore can be suitably used.

  Further, the average particle size of the inorganic particles can be set to 2 μm or less. When the average particle size of the inorganic particles is 2 μm or less, it is possible to prevent the inorganic particles from damaging the film. The average particle size of the inorganic particles is more preferably 0.90 to 1.2 μm.

  Here, the average particle size can be measured by a particle size distribution meter (“SALD2200”, Shimadzu Corporation).

  The shape of the inorganic particles is preferably irregular. The resistance to impurities is further improved. Further, the particle size distribution of the inorganic particles is preferably broad.

  The inorganic particles may include at least one inorganic material selected from the group consisting of oxides of Group IV elements of the periodic table, nitrides of Group IV elements of the periodic table, and carbides of Group IV elements of the periodic table. preferable. More preferably, zirconium oxide particles are used from the viewpoint of durability.

  The inorganic particles are inorganic particles produced by pulverizing a raw ore of inorganic particles, or by melting and refining a raw ore of inorganic particles, the spherical particles having a uniform particle diameter are converted into inorganic particles. It is preferably a particle.

  The method of grinding the ore is not particularly limited, and examples thereof include a ball mill, a bead mill, a colloid mill, a conical mill, a disk mill, an edge mill, a milling mill, a hammer mill, a pellet mill, a VSI mill, a wheely mill, a roller mill, and a jet mill. Further, it is preferable to wash after pulverization, and at that time, it is preferable to perform an acid treatment as a washing method. Thereby, impurities such as iron adhering to the surface of the inorganic particles can be reduced.

  Preferably, the coating layer contains a binder. The binder is a component that forms the coating layer by holding the inorganic particles on the surface of the ion exchange membrane. The binder preferably contains a fluorinated polymer from the viewpoint of resistance to an electrolytic solution or a product generated by electrolysis.

  As the binder, it is more preferable that the binder is a fluorine-containing polymer having a carboxylic acid group or a sulfonic acid group, from the viewpoint of resistance to an electrolytic solution or a product by electrolysis, and adhesion to the surface of the ion exchange membrane. preferable. When a coating layer is provided on a layer containing a fluorinated polymer having a sulfonic acid group (sulfonic acid layer), it is more preferable to use a fluorinated polymer having a sulfonic acid group as a binder of the coating layer. . When a coating layer is provided on a layer containing a fluorinated polymer having a carboxylic acid group (a carboxylic acid layer), a fluorinated polymer having a carboxylic acid group may be used as a binder of the coating layer. More preferred.

  In the coating layer, the content of the inorganic particles is preferably from 40 to 90% by mass, and more preferably from 50 to 90% by mass. Further, the content of the binder is preferably from 10 to 60% by mass, and more preferably from 10 to 50% by mass.

The distribution density of the coating layer in the ion exchange membrane is preferably 0.05 to ² mg / cm ² . Further, when the ion exchange membrane has an uneven shape on the surface, the distribution density of the coating layer is preferably 0.5 to ² mg / cm ² .

  The method for forming the coating layer is not particularly limited, and a known method can be used. For example, there is a method in which a coating liquid in which inorganic particles are dispersed in a solution containing a binder is applied by spraying or the like.

(Reinforced core material)
The ion exchange membrane preferably has a reinforced core disposed inside the membrane body.

  The reinforced core is a member that enhances the strength and dimensional stability of the ion exchange membrane. By arranging the reinforcing core inside the membrane main body, in particular, the expansion and contraction of the ion exchange membrane can be controlled within a desired range. Such an ion exchange membrane does not unnecessarily expand or contract during electrolysis or the like, and can maintain excellent dimensional stability for a long period of time.

  The configuration of the reinforcing core material is not particularly limited, and may be formed by, for example, spinning a yarn called a reinforcing yarn. The reinforcing yarn as referred to herein is a member constituting a reinforcing core material, which can impart desired dimensional stability and mechanical strength to the ion exchange membrane, and can be stably present in the ion exchange membrane. Refers to yarn. By using a reinforcing core obtained by spinning such a reinforcing yarn, it is possible to impart more excellent dimensional stability and mechanical strength to the ion exchange membrane.

  The material of the reinforcing core material and the reinforcing yarn used therefor is not particularly limited, but is preferably a material having resistance to acids, alkalis, and the like, and is required to have long-term heat resistance and chemical resistance. Fibers composed of a base polymer are preferred.

  Examples of the fluorinated polymer used for the reinforcing core include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), and tetrafluoroethylene-ethylene copolymer (ETFE) , A tetrafluoroethylene-hexafluoropropylene copolymer, a trifluorochloroethylene-ethylene copolymer, a vinylidene fluoride polymer (PVDF), and the like. Among these, it is preferable to use fibers made of polytetrafluoroethylene, particularly from the viewpoint of heat resistance and chemical resistance.

  The yarn diameter of the reinforcing yarn used for the reinforcing core material is not particularly limited, but is preferably 20 to 300 denier, more preferably 50 to 250 denier. The weaving density (the number of punches per unit length) is preferably 5 to 50 / inch. The form of the reinforced core material is not particularly limited. For example, a woven cloth, a nonwoven cloth, a knitted cloth, or the like is used, and the woven cloth form is preferable. The thickness of the woven fabric is preferably 30 to 250 μm, more preferably 30 to 150 μm.

  As the woven or knitted fabric, monofilaments, multifilaments, or yarns or slit yarns thereof can be used, and various weaving methods such as plain weave, entangled weave, knitting, cord weaving, and shearsack can be used.

  The weaving method and arrangement of the reinforcing core material in the membrane main body are not particularly limited, and can be appropriately arranged in consideration of the size and shape of the ion exchange membrane, physical properties desired for the ion exchange membrane, the use environment, and the like. .

  For example, the reinforcing core may be arranged along a predetermined direction of the membrane body, but from the viewpoint of dimensional stability, the reinforcing core is arranged along a predetermined first direction, and the first Preferably, another reinforcing core is arranged along a second direction substantially perpendicular to the direction. By arranging a plurality of reinforcing cores so as to be substantially perpendicular to the inside of the longitudinal membrane main body of the membrane main body, it is possible to impart more excellent dimensional stability and mechanical strength in multiple directions. For example, an arrangement in which a reinforcing core material (warp) arranged along the longitudinal direction and a reinforcing core material (weft) arranged along the lateral direction on the surface of the membrane main body is preferable. Plain weave in which warp yarns and weft yarns are alternately raised and sinked and driven in, and entangled weaves in which two warp yarns are twisted and woven with weft yarns. It is more preferable to use a tapered weave or the like from the viewpoints of dimensional stability, mechanical strength, and manufacturability.

  In particular, it is preferable that the reinforcing core material is arranged along both the MD direction (Machine Direction direction) and the TD direction (Transverse Direction direction) of the ion exchange membrane. That is, it is preferable to be plain woven in the MD direction and the TD direction. Here, the MD direction is a direction (flow direction) in which a membrane main body and various core materials (for example, a reinforced core material, a reinforced yarn, a sacrifice yarn described later, and the like) are conveyed in a later-described ion exchange membrane manufacturing process. In other words, the TD direction refers to a direction substantially perpendicular to the MD direction. A yarn woven along the MD direction is called an MD yarn, and a yarn woven along the TD direction is called a TD yarn. Usually, an ion exchange membrane used for electrolysis is rectangular in shape, and the longitudinal direction is often the MD direction and the width direction is the TD direction in many cases. By incorporating the reinforcing core material as the MD yarn and the reinforcing core material as the TD yarn, more excellent dimensional stability and mechanical strength in multiple directions can be imparted.

  The arrangement interval of the reinforcing core material is not particularly limited, and may be appropriately set in consideration of the physical properties desired for the ion exchange membrane, the use environment, and the like.

  The aperture ratio of the reinforced core material is not particularly limited, and is preferably 30% or more, more preferably 50% or more and 90% or less. The aperture ratio is preferably 30% or more from the viewpoint of the electrochemical properties of the ion exchange membrane, and is preferably 90% or less from the viewpoint of the mechanical strength of the ion exchange membrane.

  The aperture ratio of the reinforced core is defined as the total surface area through which substances such as ions (electrolyte solution and cations contained therein (eg, sodium ions)) can pass through on one surface area (A) of the membrane main body. It means the ratio (B / A) of the area (B). The total area (B) of the surface through which substances such as ions can pass means the total area of a region in the ion exchange membrane where cations, electrolytes, and the like are not blocked by the reinforcing core material contained in the ion exchange membrane. it can.

  FIG. 3 is a schematic diagram for explaining the aperture ratio of the reinforced core constituting the ion exchange membrane. FIG. 3 is an enlarged view of a part of the ion exchange membrane, showing only the arrangement of the reinforcing cores 21a and 21b in the region, and omits illustration of other members.

The area surrounded by the reinforcing core 21a arranged in the longitudinal direction and the reinforcing core 21b arranged in the horizontal direction, and the area (A) of the region including the area of the reinforcing core is calculated from the area of the reinforcing core. By subtracting the total area (C) of the above, the total area (B) of the area through which substances such as ions can pass in the area (A) of the above-described area can be obtained. That is, the aperture ratio can be obtained by the following equation (I).
Aperture ratio = (B) / (A) = ((A)-(C)) / (A) (I)

  Among the reinforced core materials, a particularly preferred form is a tape yarn or a highly oriented monofilament containing PTFE from the viewpoint of chemical resistance and heat resistance. Specifically, a tape yarn obtained by slitting a high-strength porous sheet made of PTFE into a tape shape, or 50 to 300 denier of highly oriented monofilament made of PTFE is used, and the weaving density is 10 to 50 fibers / More preferably, the reinforcing core material has a plain weave of inches and a thickness in the range of 50 to 100 μm. The aperture ratio of the ion exchange membrane containing such a reinforcing core material is more preferably 60% or more.

  Examples of the shape of the reinforcing yarn include a round yarn and a tape-like yarn.

(Communication hole)
The ion exchange membrane preferably has a communication hole inside the membrane main body.

  The communication hole refers to a hole that can serve as a flow path for ions generated during electrolysis or an electrolytic solution. The communication hole is a tubular hole formed inside the membrane main body, and is formed by elution of a sacrificial core material (or sacrificial thread) described later. The shape and diameter of the communication hole can be controlled by selecting the shape and diameter of the sacrificial core (sacrifice yarn).

  By forming the communication holes in the ion exchange membrane, the mobility of the electrolyte during electrolysis can be secured. Although the shape of the communication hole is not particularly limited, the shape of the sacrificial core material used for forming the communication hole can be obtained according to a manufacturing method described later.

  The communication holes are preferably formed so as to alternately pass between the anode side (sulfonic acid layer side) and the cathode side (carboxylic acid layer side) of the reinforcing core material. With such a structure, in the portion where the communication hole is formed on the cathode side of the reinforcing core material, ions (for example, sodium ions) transported through the electrolytic solution filled in the communication hole are used for the reinforcing core material. It can also flow to the cathode side. As a result, since the flow of the cations is not blocked, the electric resistance of the ion exchange membrane can be further reduced.

  The communication hole may be formed along only one predetermined direction of the membrane main body constituting the ion exchange membrane, but from the viewpoint of exhibiting more stable electrolysis performance, the longitudinal direction and the lateral direction of the membrane main body are different from each other. Are preferably formed in both directions.

〔Production method〕
A preferred method for producing the ion exchange membrane includes a method having the following steps (1) to (6).
(1) Step: a step of producing a fluorine-containing polymer having an ion-exchange group or an ion-exchange group precursor that can be converted to an ion-exchange group by hydrolysis.
(2) Step: If necessary, at least a plurality of reinforcing cores and a sacrificial yarn having a property of dissolving in an acid or an alkali and forming a communication hole are woven, so that adjacent reinforcing cores are connected to each other. A step of obtaining a reinforcing material having a sacrificial thread disposed therebetween.
(3) Step: a step of forming a film of the fluorinated polymer having an ion-exchange group or an ion-exchange group precursor that can become an ion-exchange group by hydrolysis.
(4) Step: a step of embedding the reinforcing material as necessary in the film to obtain a membrane main body in which the reinforcing material is disposed.
Step (5): Step of hydrolyzing the membrane main body obtained in step (4) (hydrolysis step).
Step (6): a step of providing a coating layer on the film body obtained in step (5) (coating step).

  Hereinafter, each step will be described in detail.

(1) Step: Step of Producing Fluoropolymer In step (1), a fluorinated polymer is produced using the raw material monomers described in the first to third groups. In order to control the ion exchange capacity of the fluorinated polymer, the mixing ratio of the raw material monomers may be adjusted in the production of the fluorinated polymer forming each layer.

(2) Process: manufacturing process of reinforcing material The reinforcing material is a woven fabric or the like in which a reinforcing yarn is woven. The reinforcing material is embedded in the film to form a reinforced core. When forming an ion exchange membrane having a communication hole, the sacrificial yarn is also woven into the reinforcing material. In this case, the mixed amount of the sacrificial yarn is preferably 10 to 80% by mass, more preferably 30 to 70% by mass of the whole reinforcing material. By weaving the sacrificial thread, misalignment of the reinforced core material can be prevented.

  The sacrificial yarn has solubility in the film manufacturing process or in an electrolytic environment, and is made of rayon, polyethylene terephthalate (PET), cellulose, polyamide, or the like. Further, polyvinyl alcohol or the like having a thickness of 20 to 50 denier and comprising a monofilament or a multifilament is also preferable.

  In the step (2), the aperture ratio and the arrangement of the communication holes can be controlled by adjusting the arrangement of the reinforcing core material and the sacrificial yarn.

(3) Step: Film forming step In the (3) step, the fluorinated polymer obtained in the above (1) step is formed into a film using an extruder. The film may have a single-layer structure, a two-layer structure of a sulfonic acid layer and a carboxylic acid layer, or a multilayer structure of three or more layers, as described above.

As a method of forming a film, for example, the following method is used.
A method in which a fluoropolymer having a carboxylic acid group and a fluoropolymer having a sulfonic acid group are separately formed into films.
A method of forming a composite film by co-extrusion of a fluorinated polymer having a carboxylic acid group and a fluorinated polymer having a sulfonic acid group.

  The number of films may be plural. Further, co-extrusion of different kinds of films is preferable because it contributes to increasing the adhesive strength at the interface.

Step (4): Step of Obtaining a Membrane Body In the step (4), the reinforcing material obtained in the step (2) is embedded in the film obtained in the step (3) to remove the film body in which the reinforcing material is present. obtain.

  As a preferable method of forming the membrane main body, (i) a fluorine-containing polymer having a carboxylic acid group precursor (for example, a carboxylic acid ester functional group) located on the cathode side (hereinafter, a layer composed of the first layer is referred to as a first layer) And a fluorinated polymer having a sulfonic acid group precursor (for example, a sulfonyl fluoride functional group) (hereinafter, a layer composed of the second layer) is formed into a film by a co-extrusion method. Using a vacuum source, a reinforcing material and a second layer / first layer composite film are laminated in this order on a flat plate or drum having a large number of pores on the surface, through a heat-resistant release paper having air permeability. And removing the air between the layers under reduced pressure at a temperature at which each polymer melts; (ii) Apart from the second layer / first layer composite film, a method comprising a sulfonic acid group precursor. Fluorine polymerization (Third layer) is formed into a film by itself in advance, and if necessary, using a heat source and a vacuum source, through a heat-resistant release paper having air permeability on a flat plate or a drum having many pores on the surface. Then, the third layer film, the reinforcing core material, and the composite film composed of the second layer / first layer are laminated in this order, and integrated while removing the air between the layers under reduced pressure at a temperature at which each polymer melts. Method.

  Here, co-extrusion of the first layer and the second layer contributes to increasing the adhesive strength at the interface.

  Further, the method of integrating under reduced pressure has a feature that the thickness of the third layer on the reinforcing material is larger than that of the pressure press method. Further, since the reinforcing material is fixed to the inner surface of the membrane main body, the ion exchange membrane has a performance capable of sufficiently maintaining the mechanical strength.

  It should be noted that the above-described variation of the lamination is merely an example, and a suitable lamination pattern (for example, a combination of the respective layers) is appropriately selected in consideration of a desired layer configuration and physical properties of the film main body, and then the co-extrusion is performed. can do.

  In addition, for the purpose of further improving the electrical performance of the ion exchange membrane, between the first layer and the second layer, the first layer made of a fluoropolymer having both a carboxylic acid group precursor and a sulfonic acid group precursor It is also possible to further interpose four layers, or to use a fourth layer made of a fluorine-containing polymer having both a carboxylic acid group precursor and a sulfonic acid group precursor instead of the second layer.

  The method for forming the fourth layer may be a method in which a fluorinated polymer having a carboxylic acid group precursor and a fluorinated polymer having a sulfonic acid group precursor are separately produced and then mixed, and the carboxylic acid A method using a copolymer of a monomer having a group precursor and a monomer having a sulfonic acid group precursor may be used.

  When the fourth layer is configured as an ion exchange membrane, a co-extruded film of the first layer and the fourth layer is formed, and the third layer and the second layer are separately formed into a film separately from the first layer and the second layer. The layers may be laminated by a method, or three layers of a first layer / fourth layer / second layer may be coextruded at a time to form a film.

  In this case, the direction in which the extruded film flows is the MD direction. In this way, the membrane main body containing the fluorinated polymer having an ion exchange group can be formed on the reinforcing material.

  Further, the ion exchange membrane preferably has a protruding portion made of a fluorinated polymer having a sulfonic acid group, that is, a convex portion, on the surface side of the sulfonic acid layer. The method for forming such a convex portion is not particularly limited, and a known method for forming a convex portion on a resin surface can be employed. Specifically, for example, a method of embossing the surface of the film main body may be mentioned. For example, when the above-described composite film is integrated with a reinforcing material or the like, the above-described convex portion can be formed by using release paper that has been embossed in advance. When a convex portion is formed by embossing, the height and arrangement density of the convex portion can be controlled by controlling the emboss shape (the shape of release paper) to be transferred.

(5) Hydrolysis Step In the (5) step, a step (hydrolysis step) of hydrolyzing the membrane body obtained in the step (4) to convert an ion exchange group precursor into an ion exchange group is performed.

  In the step (5), elution holes can be formed in the membrane main body by dissolving and removing the sacrificial yarn contained in the membrane main body with an acid or an alkali. Note that the sacrificial yarn may remain in the communication hole without being completely dissolved and removed. Further, the sacrificial thread remaining in the communication hole may be dissolved and removed by the electrolytic solution when the ion exchange membrane is subjected to electrolysis.

  The sacrificial yarn is soluble in an acid or an alkali in a process of manufacturing an ion exchange membrane or in an electrolytic environment, and a communication hole is formed at the site by elution of the sacrificial yarn.

  The step (5) can be performed by immersing the membrane body obtained in the step (4) in a hydrolysis solution containing an acid or an alkali. As the hydrolysis solution, for example, a mixed solution containing KOH and DMSO (Dimethyl sulfoxide) can be used.

  It is preferable that the mixed solution contains 2.5 to 4.0 N of KOH and 25 to 35% by mass of DMSO.

  The hydrolysis temperature is preferably from 70 to 100 ° C. The higher the temperature, the greater the apparent thickness. More preferably, it is 75 to 100 ° C.

  The hydrolysis time is preferably from 10 to 120 minutes. The longer the time, the greater the apparent thickness can be. More preferably, it is 20 to 120 minutes.

  Here, the step of forming the communication hole by dissolving the sacrificial yarn will be described in more detail. FIGS. 4A and 4B are schematic diagrams for explaining a method of forming a communication hole of an ion exchange membrane.

  FIGS. 4A and 4B show only the communication hole 504 formed by the reinforcing yarn 52, the sacrificial yarn 504a, and the sacrificial yarn 504a, and other members such as the membrane main body are not shown. ing.

  First, the reinforcing yarn 52 that forms the reinforcing core in the ion exchange membrane and the sacrificial yarn 504a for forming the communication hole 504 in the ion exchange membrane are used as braided reinforcing materials. Then, in the step (5), the communication hole 504 is formed by elution of the sacrificial thread 504a.

  According to the above-described method, the method of weaving the reinforcing yarns 52 and the sacrificial yarns 504a can be easily adjusted according to the arrangement of the reinforcing core material and the communication holes in the membrane main body of the ion exchange membrane.

  FIG. 4A illustrates a plain-woven reinforcing material in which the reinforcing yarn 52 and the sacrificial yarn 504a are woven along both the longitudinal direction and the horizontal direction on the paper surface, but the reinforcing yarn 52 in the reinforcing material is used as necessary. The arrangement of the sacrificial thread 504a can be changed.

(6) Coating Step In the step (6), a coating liquid containing inorganic particles obtained by crushing or melting the ore and a binder and a binder is prepared, and the coating liquid is applied to the ion exchange membrane obtained in the step (5). A coating layer can be formed by applying and drying the surface.

As a binder, a fluorinated polymer having an ion exchange group precursor is hydrolyzed with an aqueous solution containing dimethyl sulfoxide (DMSO) and potassium hydroxide (KOH), and then immersed in hydrochloric acid to form a pair of the ion exchange group. A binder in which an ion is substituted with H ⁺ (for example, a fluorinated polymer having a carboxyl group or a sulfo group) is preferable. This is preferable because it is easily dissolved in water or ethanol described below.

  This binder is dissolved in a mixed solution of water and ethanol. The volume ratio of water to ethanol is preferably 10: 1 to 1:10, more preferably 5: 1 to 1: 5, and still more preferably 2: 1 to 1: 2. In the thus obtained solution, the inorganic particles are dispersed with a ball mill to obtain a coating solution. At this time, the average particle size and the like of the particles can be adjusted by adjusting the time and rotation speed at the time of dispersion. The preferred blending amounts of the inorganic particles and the binder are as described above.

  The concentration of the inorganic particles and the binder in the coating liquid is not particularly limited, but a thin coating liquid is preferable. Thereby, it becomes possible to apply uniformly on the surface of the ion exchange membrane.

  When dispersing the inorganic particles, a surfactant may be added to the dispersion. As the surfactant, a nonionic surfactant is preferable, and examples thereof include HS-210, NS-210, P-210, and E-212 manufactured by NOF Corporation.

  The ion exchange membrane is obtained by applying the obtained coating liquid to the ion exchange membrane surface by spray coating or roll coating.

(Microporous membrane)
The microporous membrane of the present embodiment is not particularly limited, and various microporous membranes can be applied.
The porosity of the microporous membrane of the present embodiment is not particularly limited, but may be, for example, 20 to 90, and preferably 30 to 85. The porosity can be calculated, for example, by the following equation.
Porosity = (1− (weight of film in dry state) / (volume calculated from thickness, width, length of film and weight calculated from density of film material)) × 100
The average pore size of the microporous membrane of the present embodiment is not particularly limited, but can be, for example, 0.01 μm to 10 μm, and preferably 0.05 μm to 5 μm. The average pore diameter is determined, for example, by cutting the membrane perpendicularly to the thickness direction and observing the cut surface by FE-SEM. The diameter of the observed hole can be determined by measuring about 100 points and averaging.
The thickness of the microporous membrane of the present embodiment is not particularly limited, but can be, for example, 10 μm to 1000 μm, and preferably 50 μm to 600 μm. The thickness can be measured using, for example, a micrometer (manufactured by Mitutoyo Corporation) or the like.
Specific examples of the microporous film as described above include Zirfon Perl UTP 500 (also referred to as Zirfon film in the present embodiment) manufactured by Agfa, International Publication No. 2013-183584, and International Publication No. 2006-203701. And the like.

  In the present embodiment, it is preferable that the diaphragm includes a first ion exchange resin layer and a second ion exchange resin layer having an EW (ion exchange equivalent) different from the first ion exchange resin layer. . Further, it is preferable that the diaphragm includes a first ion-exchange resin layer and a second ion-exchange resin layer having a functional group different from that of the first ion-exchange resin layer. The ion exchange equivalent can be adjusted by the functional group to be introduced, and the functional groups that can be introduced are as described above.

(Fixing means)
In the present embodiment, the electrode for electrolysis is fixed to at least one region on the surface of the existing electrode, and in this specification, one or more regions are also referred to as a fixed region. The fixing region in the present embodiment has a function of suppressing the separation between the electrode for electrolysis and the existing electrode, and is not particularly limited as long as the portion for fixing the electrode for electrolysis to the existing electrode is used. In some cases, the fixing region may be formed by the fixing means, and in other cases, the fixing region may be formed by the fixing member that is separate from the electrode for electrolysis. Note that the fixed region in the present embodiment may exist only at a position corresponding to the energized surface during electrolysis, or may extend to a position corresponding to the non-energized surface. Note that the “current-carrying surface” corresponds to a portion designed to move the electrolyte between the anode chamber and the cathode chamber. The “non-conductive surface” means a portion other than the conductive surface.

  In the present embodiment, the fixing structure in the fixing region is not limited. For example, the fixing structure exemplified below can be adopted. In addition, each fixing structure can employ | adopt only 1 type, and can employ | adopt it in combination of 2 or more types.

In the present embodiment, in the fixing region, it is preferable that at least a part of the electrode for electrolysis penetrates the existing electrode and is fixed. Such an embodiment will be described with reference to FIG.
FIGS. 5A and 5B show a state in which at least a part of the electrode for electrolysis 101 passes through the existing electrode 102 and is fixed. Here, both the electrode for electrolysis 101 and the existing electrode 102 are illustrated as porous metal electrodes (the same applies to FIGS. 6 to 8 below). First, as shown in the upper part of FIG. 5A, a deteriorated portion of the existing electrode 102 is cut into a rectangular shape to form a cut portion 102a. The shape of the cut portion is merely an example, and is not limited to a rectangular shape, and may be various shapes (the same applies to FIGS. 6 to 8 below). Next, it is preferable to use, as the electrode for electrolysis 101, an electrode having a metal wire 101a extending from an end thereof by a predetermined length. That is, as shown in the upper part of FIG. 5A, the electrode for electrolysis 101 is applied so as to completely cover the cut-off portion 102a, and then the metal wire 101a is inserted through the inside of the existing electrode 102 and penetrated. The metal wire 101a is curved and fixed on the surface opposite to the contact surface for the electrode 101 for use. FIG. 5B is a cross-sectional view taken along line XX ′ of FIG. 5A. The metal wire 101a may be bent in advance and then inserted into the existing electrode 102.

In the present embodiment, in the fixing region, it is preferable that at least a part of the electrode for electrolysis is positioned and fixed inside the existing electrode. Such an embodiment will be described with reference to FIG.
6A and 6B show a state where at least a part of the electrode for electrolysis 101 is fixed inside the existing electrode 102. FIG. First, as shown in the upper part of FIG. 6A, a deteriorated portion of the existing electrode 102 is cut into a rectangular shape to form a cut portion 102a. Next, it is preferable to use, as the electrode for electrolysis 101, an electrode having a metal wire 101a extending from an end thereof by a predetermined length. That is, as shown in the upper part of FIG. 6A, the electrode for electrolysis 101 is applied so as to completely cover the cut portion 102a, and then the metal wire 101a is inserted into the existing electrode 102, and the metal wire 101a is inserted inside the existing electrode 102. Curve and secure. FIG. 6B is a sectional view taken along the line YY ′ of FIG. 6A. The metal wire 101a may be bent in advance and then inserted into the existing electrode 102.

  In the present embodiment, it is preferable to further include a fixing member for fixing the existing electrode and the electrode for electrolysis. Such an embodiment will be described with reference to FIGS.

The fixing structure shown in FIG. 7 has a structure in which the electrode for electrolysis 101 is fixed to the existing electrode 102 using a fixing member (a resin or metal thread or the like) separate from the electrode for electrolysis 101 and the existing electrode 102. is there. More specifically, FIG. 7 shows an example in which a thread made of PTFE (polytetrafluoroethylene) is used, and an electrolytic solution is applied from the contact surface of the existing electrode 102 to the surface opposite to the contact surface. The configuration in which the electrodes 101 are sewn is shown. The existing electrode 102 does not necessarily need to be penetrated by a fixing member, and may be fixed by the fixing member so as not to be separated from the electrolytic electrode 101. The material of the fixing member is not particularly limited, and for example, a material made of metal, resin, or the like can be used. In the case of a metal, nickel, nichrome, titanium, stainless steel (SUS) and the like can be mentioned. These oxides may be used. Examples of the resin include fluororesins (for example, PTFE (polytetrafluoroethylene), PFA (copolymer of tetrafluoroethylene and perfluoroalkoxyethylene), ETFE (copolymer of tetrafluoroethylene and ethylene), and the resins described below. , PVDF (polyvinylidene fluoride), EPDM (ethylene propylene diene rubber), PP (polyethylene), PE (polypropylene), nylon, aramid, and the like.
It is also possible to fix the electrode for electrolysis 101 and the existing electrode 102 using a fixing mechanism such as a tucker.

The fixing structure shown in FIG. 8 is a structure in which an organic resin (adhesive) is interposed between the electrode for electrolysis 101 and the existing electrode 102 and fixed. That is, FIG. 8 shows a structure in which an organic resin as a fixing member is disposed at a predetermined position (a position to be a fixing region) between the electrode for electrolysis 101 and the existing electrode 102, and is fixed by bonding. For example, an organic resin is applied to at least one of the adhesion surfaces of the electrode for electrolysis 101 and the existing electrode 102. Then, by attaching the electrode for electrolysis 101 and the existing electrode 102, the fixing structure shown in FIG. 8 can be formed. The material of the organic resin is not particularly limited. For example, a fluororesin (for example, PTFE, PFA, ETFE) or the like can be used. In addition, a commercially available fluorine-based adhesive, a PTFE dispersion, or the like can be appropriately used. In addition, general-purpose vinyl acetate adhesive, ethylene vinyl acetate copolymer adhesive, acrylic resin adhesive, α-olefin adhesive, styrene butadiene rubber latex adhesive, vinyl chloride resin adhesive, chloroprene adhesive Agent, nitrile rubber adhesive, urethane rubber adhesive, epoxy adhesive, silicone resin adhesive, modified silicone adhesive, epoxy / modified silicone resin adhesive, silylated urethane resin adhesive, cyanoacrylate A system adhesive or the like can also be used.
In the present embodiment, an organic resin that dissolves in the electrolytic solution or dissolves and decomposes during the electrolysis may be used. The organic resin that dissolves in the electrolytic solution or dissolves and decomposes during the electrolysis is not limited to the following. For example, a vinyl acetate-based adhesive, an ethylene-vinyl acetate copolymer-based adhesive, an acrylic resin-based adhesive, α- Olefin adhesive, styrene butadiene rubber latex adhesive, vinyl chloride resin adhesive, chloroprene adhesive, nitrile rubber adhesive, urethane rubber adhesive, epoxy adhesive, silicone resin adhesive, modified silicone Adhesives, epoxy / modified silicone resin adhesives, silylated urethane resin adhesives, cyanoacrylate adhesives, and the like.

  Instead of the above-mentioned adhesive, the electrode 101 for electrolysis is applied so as to cover the cut portion 102a of the existing electrode 102, and then the four corners (four points) of the electrode 101 for electrolysis are spot-welded to join them. May be. Welding may be performed linearly. Known welding methods such as TIG welding, spot welding, seam welding, and laser welding can be used.

In addition to the above, there is a method in which water is interposed between the electrode for electrolysis and the existing electrode, and integration is performed by the surface tension of the water. In this embodiment, not only water but also any liquid that generates surface tension, such as an organic solvent, can be used. As the surface tension of the liquid increases, the force applied between the existing electrode and the electrode for electrolysis increases, so that a liquid having a high surface tension is preferable. Examples of the liquid include the following (the numerical value in parentheses is the surface tension of the liquid at 20 ° C.).
Hexane (20.44 mN / m), acetone (23.30 mN / m), methanol (24.00 mN / m), ethanol (24.05 mN / m), ethylene glycol (50.21 mN / m), water (72.76 mN / m) / M)
If the liquid has a large surface tension, the existing electrode and the electrode for electrolysis are easily fixed, and the existing electrode tends to be repaired more easily. The amount of liquid between the existing electrode and the electrode for electrolysis may be such that the liquid adheres to each other due to surface tension.As a result, the amount of liquid is small. There is no.
From the viewpoint of practical use, it is preferable to use a liquid having a surface tension of 24 mN / m to 80 mN / m, such as ethanol, ethylene glycol, and water. In particular, water or an aqueous solution obtained by dissolving caustic soda, potassium hydroxide, lithium hydroxide, sodium hydrogencarbonate, potassium hydrogencarbonate, sodium carbonate, potassium carbonate, or the like in water and making the solution alkaline is preferable. In addition, a surfactant can be contained in these liquids to adjust the surface tension. By including the surfactant, the adhesiveness between the existing electrode and the electrode for electrolysis changes, and the handling property can be adjusted. The surfactant is not particularly limited, and any of an ionic surfactant and a nonionic surfactant can be used.

As described above, the laminate according to the present embodiment may have various fixed regions at various positions. It is preferable that the above “applied force” is satisfied. That is, the applied force per unit mass / unit area in the non-fixed region of the electrode for electrolysis is preferably less than 1.5 N / mg · cm ² .

(Electrolysis tank)
The electrolytic cell of the present embodiment includes the electrolytic cell of the present embodiment, in which an existing electrode or a new electrode is arranged. Hereinafter, an embodiment of the electrolytic cell will be described in detail by taking, as an example, a case in which an ion exchange membrane is used as a diaphragm and salt electrolysis is performed. However, in the present embodiment, the electrolytic cell is not limited to being used for salt electrolysis, and is also used for, for example, water electrolysis and a fuel cell.

(Electrolysis cell)
FIG. 9 is a cross-sectional view of the electrolytic cell 50.
The electrolytic cell 50 was installed in the anode chamber 60, the cathode chamber 70, the partition wall 80 installed between the anode chamber 60 and the cathode chamber 70, the anode 11 installed in the anode chamber 60, and the cathode chamber 70. And a cathode 21. If necessary, a reverse current absorber 18 having a base material 18a and a reverse current absorbing layer 18b formed on the base material 18a and installed in the cathode chamber may be provided. The anode 11 and the cathode 21 belonging to one electrolytic cell 50 are electrically connected to each other. In other words, the electrolytic cell 50 includes the following cathode structure. The cathode structure 90 includes a cathode chamber 70, a cathode 21 installed in the cathode chamber 70, and a reverse current absorber 18 installed in the cathode chamber 70. The reverse current absorber 18 is shown in FIG. As shown, it has a base material 18a and a reverse current absorption layer 18b formed on the base material 18a, and the cathode 21 and the reverse current absorption layer 18b are electrically connected. The cathode chamber 70 further includes a current collector 23, a support 24 that supports the current collector, and a metal elastic body 22. The metal elastic body 22 is provided between the current collector 23 and the cathode 21. The support 24 is provided between the current collector 23 and the partition 80. The current collector 23 is electrically connected to the cathode 21 via the metal elastic body 22. The partition wall 80 is electrically connected to the current collector 23 via the support 24. Therefore, the partition 80, the support 24, the current collector 23, the metal elastic body 22, and the cathode 21 are electrically connected. The cathode 21 and the reverse current absorption layer 18b are electrically connected. The cathode 21 and the reverse current absorption layer may be directly connected, or may be indirectly connected via a current collector, a support, a metal elastic body, a partition, or the like. It is preferable that the entire surface of the cathode 21 is covered with a catalyst layer for a reduction reaction. Further, the form of the electrical connection is such that the partition wall 80 and the support 24, the support 24 and the current collector 23, the current collector 23 and the metal elastic body 22 are directly attached, and the cathode 21 is laminated on the metal elastic body 22. It may be a form to be performed. As a method of directly attaching these components to each other, welding and the like can be mentioned. Further, the reverse current absorber 18, the cathode 21, and the current collector 23 may be collectively referred to as a cathode structure 90.

  FIG. 10 is a sectional view of two adjacent electrolysis cells 50 in the electrolysis tank 4. FIG. 11 shows the electrolytic cell 4. FIG. 12 shows a process of assembling the electrolytic cell 4. As shown in FIG. 11, the electrolytic cell 50, the cation exchange membrane 51, and the electrolytic cell 50 are arranged in series in this order. A cation exchange membrane 51 is disposed between an anode chamber of one of the adjacent electrolytic cells 50 and a cathode chamber of the other electrolytic cell 50 of two adjacent electrolytic cells in the electrolytic cell. That is, the anode chamber 60 of the electrolysis cell 50 and the cathode chamber 70 of the electrolysis cell 50 adjacent thereto are separated by the cation exchange membrane 51. As shown in FIG. 10, the electrolytic cell 4 is composed of a plurality of electrolytic cells 50 connected in series via a cation exchange membrane 51. That is, the electrolytic cell 4 is a bipolar electrolytic cell including a plurality of electrolytic cells 50 arranged in series and a cation exchange membrane 51 arranged between adjacent electrolytic cells 50. As shown in FIG. 12, the electrolytic cell 4 is assembled by arranging a plurality of electrolytic cells 50 in series via a cation exchange membrane 51 and connecting them by a press 5.

  The electrolytic cell 4 has an anode terminal 7 and a cathode terminal 6 connected to a power supply. The anode 11 of the electrolytic cell 50 located at the end of the plurality of electrolytic cells 50 connected in series in the electrolytic cell 4 is electrically connected to the anode terminal 7. The cathode 21 of the electrolysis cell located at the end opposite to the anode terminal 7 among the plurality of electrolysis cells 2 connected in series in the electrolysis tank 4 is electrically connected to the cathode terminal 6. The current at the time of electrolysis flows from the anode terminal 7 side to the cathode terminal 6 via the anode and the cathode of each electrolytic cell 50. At both ends of the connected electrolytic cells 50, an electrolytic cell having only an anode chamber (anode terminal cell) and an electrolytic cell having only a cathode chamber (cathode terminal cell) may be arranged. In this case, the anode terminal 7 is connected to the anode terminal cell arranged at one end, and the cathode terminal 6 is connected to the cathode terminal cell arranged at the other end.

  When performing salt water electrolysis, salt water is supplied to each anode chamber 60, and pure water or a low-concentration sodium hydroxide aqueous solution is supplied to the cathode chamber 70. Each liquid is supplied to each electrolytic cell 50 from an electrolyte supply pipe (omitted in the figure) via an electrolyte supply hose (omitted in the figure). In addition, the electrolytic solution and products generated by the electrolysis are recovered from an electrolytic solution recovery tube (omitted in the figure). In the electrolysis, sodium ions in the salt water move from the anode chamber 60 of one electrolytic cell 50 through the cation exchange membrane 51 to the cathode chamber 70 of the next electrolytic cell 50. Therefore, the current during electrolysis flows along the direction in which the electrolysis cells 50 are connected in series. That is, the current flows from the anode chamber 60 to the cathode chamber 70 via the cation exchange membrane 51. With the electrolysis of the salt water, chlorine gas is generated on the anode 11 side, and sodium hydroxide (solute) and hydrogen gas are generated on the cathode 21 side.

(Anode room)
The anode chamber 60 has the anode 11 or the anode power feeder 11. When the electrode for electrolysis in the present embodiment is inserted on the anode side, 11 functions as an anode power feeder. When the electrode for electrolysis in the present embodiment is not inserted into the anode side, 11 functions as an anode. In addition, the anode chamber 60 is disposed above the anode-side electrolyte supply unit that supplies the electrolyte to the anode chamber 60, and is disposed so as to be substantially parallel or oblique to the partition wall 80. It is preferable to have a baffle plate and an anode-side gas-liquid separation unit that is disposed above the baffle plate and separates gas from the electrolyte mixed with gas.

(anode)
When the electrode for electrolysis in the present embodiment is not inserted into the anode side, the anode 11 is provided in the frame of the anode chamber 60. As the anode 11, a metal electrode such as so-called DSA (registered trademark) can be used. DSA is a titanium-based electrode whose surface is coated with an oxide containing ruthenium, iridium, and titanium.
As the shape, any of a punched metal, a nonwoven fabric, a foamed metal, an expanded metal, a porous metal foil formed by electroforming, and a so-called woven mesh formed by knitting a metal wire can be used.

(Anode feeder)
When the electrode for electrolysis in the present embodiment is inserted on the anode side, an anode power supply 11 is provided in the frame of the anode chamber 60. As the anode power supply 11, a metal electrode such as so-called DSA (registered trademark) can be used, or titanium without a catalyst coating can be used. Further, DSA having a reduced catalyst coating thickness can also be used. Further, a used anode can be used.
As the shape, any of a punched metal, a nonwoven fabric, a foamed metal, an expanded metal, a porous metal foil formed by electroforming, and a so-called woven mesh formed by knitting a metal wire can be used.

(Anode side electrolyte supply section)
The anode-side electrolyte supply section supplies the electrolyte to the anode chamber 60, and is connected to the electrolyte supply pipe. It is preferable that the anode-side electrolyte supply unit is disposed below the anode chamber 60. As the anode-side electrolyte supply unit, for example, a pipe (dispersion pipe) having an opening formed on the surface can be used. More preferably, such a pipe is arranged along the surface of the anode 11 and parallel to the bottom 19 of the electrolytic cell. This pipe is connected to an electrolytic solution supply pipe (liquid supply nozzle) for supplying an electrolytic solution into the electrolytic cell 50. The electrolytic solution supplied from the liquid supply nozzle is transported into the electrolytic cell 50 by a pipe, and is supplied into the anode chamber 60 from an opening provided on the surface of the pipe. It is preferable to dispose the pipe along the surface of the anode 11 and in parallel with the bottom 19 of the electrolytic cell, because the electrolyte can be uniformly supplied into the anode chamber 60.

(Anode-side gas-liquid separator)
The anode-side gas-liquid separator is preferably disposed above the baffle plate. During the electrolysis, the anode-side gas-liquid separator has a function of separating the electrolytic solution from the generated gas such as chlorine gas. Unless otherwise specified, “upward” means an upward direction in the electrolytic cell 50 of FIG. 9, and “downward” means a downward direction in the electrolytic cell 50 of FIG.

  At the time of electrolysis, when the product gas generated in the electrolytic cell 50 and the electrolytic solution become a mixed phase (gas-liquid mixed phase) and are discharged out of the system, a vibration is generated due to a pressure fluctuation inside the electrolytic cell 50, and the physical property of the ion exchange membrane is increased. May cause damage. In order to suppress this, it is preferable that the electrolytic cell 50 in the present embodiment is provided with an anode-side gas-liquid separator for separating gas and liquid. It is preferable that a defoaming plate for eliminating bubbles is provided in the anode-side gas-liquid separator. When the gas-liquid multiphase flow passes through the defoaming plate, the bubbles are repelled, so that the gas and the liquid can be separated into the electrolyte and the gas. As a result, vibration during electrolysis can be prevented.

(Baffle plate)
It is preferable that the baffle plate is disposed above the anode-side electrolytic solution supply unit and is disposed substantially parallel to or oblique to the partition wall 80. The baffle plate is a partition plate that controls the flow of the electrolyte in the anode chamber 60. By providing the baffle plate, the electrolyte (salt water or the like) can be circulated internally in the anode chamber 60 to make the concentration uniform. In order to cause internal circulation, the baffle plate is preferably arranged so as to separate the space near the anode 11 from the space near the partition 80. From such a viewpoint, it is preferable that the baffle plate is provided so as to face each surface of the anode 11 and the partition 80. In the space in the vicinity of the anode partitioned by the baffle plate, the electrolytic solution concentration (salt water concentration) decreases due to the progress of electrolysis, and generated gas such as chlorine gas is generated. Thereby, a difference in specific gravity of gas and liquid is generated between the space near the anode 11 partitioned by the baffle plate and the space near the partition wall 80. By utilizing this, the internal circulation of the electrolyte in the anode chamber 60 can be promoted, and the concentration distribution of the electrolyte in the anode chamber 60 can be made more uniform.

  Although not shown in FIG. 9, a current collector may be separately provided inside the anode chamber 60. Such a current collector may have the same material and configuration as a current collector of a cathode chamber described later. In the anode chamber 60, the anode 11 itself can function as a current collector.

(Partition)
The partition 80 is arranged between the anode chamber 60 and the cathode chamber 70. The partition 80 is sometimes called a separator, and partitions the anode chamber 60 and the cathode chamber 70. As the partition 80, a known separator for electrolysis can be used, and examples thereof include a partition obtained by welding a plate made of nickel on the cathode side and titanium on the anode side.

(Cathode room)
The cathode chamber 70 functions as a cathode power supply when the electrode for electrolysis in the present embodiment is inserted on the cathode side, and 21 when the electrode for electrolysis in the present embodiment is not inserted on the cathode side. Functions as a cathode. When a reverse current absorber is provided, the cathode or the cathode power supply 21 and the reverse current absorber are electrically connected. Further, similarly to the anode chamber 60, the cathode chamber 70 preferably has a cathode-side electrolyte supply section and a cathode-side gas-liquid separation section. The description of the same components as those of the anode chamber 60 among the components of the cathode chamber 70 will be omitted.

(cathode)
When the electrode for electrolysis in the present embodiment is not inserted on the cathode side, the cathode 21 is provided in the frame of the cathode chamber 70. The cathode 21 preferably has a nickel base and a catalyst layer covering the nickel base. The components of the catalyst layer on the nickel substrate include Ru, C, Si, P, S, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Rh, Pd, Ag, Cd, In, Sn, Ta, W, Re, Os, Ir, Pt, Au, Hg, Pb, Bi, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Examples include metals such as Dy, Ho, Er, Tm, Yb, and Lu, and oxides or hydroxides of the metals. Examples of a method for forming the catalyst layer include plating, alloy plating, dispersion / composite plating, CVD, PVD, thermal decomposition, and thermal spraying. These methods may be combined. The catalyst layer may have a plurality of layers and a plurality of elements as necessary. Further, the cathode 21 may be subjected to a reduction treatment as required. The base material of the cathode 21 may be nickel, nickel alloy, iron or stainless steel plated with nickel.
As the shape, any of a punched metal, a nonwoven fabric, a foamed metal, an expanded metal, a porous metal foil formed by electroforming, and a so-called woven mesh formed by knitting a metal wire can be used.

(Cathode feeder)
When the electrode for electrolysis in the present embodiment is inserted on the cathode side, the cathode power supply 21 is provided in the frame of the cathode chamber 70. The cathode power supply 21 may be coated with a catalyst component. The catalyst component may be originally used as a cathode and may remain. The components of the catalyst layer include Ru, C, Si, P, S, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Rh, Pd, and Ag. , Cd, In, Sn, Ta, W, Re, Os, Ir, Pt, Au, Hg, Pb, Bi, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er , Tm, Yb, Lu and the like, and oxides or hydroxides of such metals. Examples of a method for forming the catalyst layer include plating, alloy plating, dispersion / composite plating, CVD, PVD, thermal decomposition, and thermal spraying. These methods may be combined. The catalyst layer may have a plurality of layers and a plurality of elements as necessary. Alternatively, nickel, nickel alloy, iron or stainless steel which is not coated with catalyst and plated with nickel may be used. The base material of the cathode power supply 21 may be nickel, nickel alloy, iron or stainless steel plated with nickel.
As the shape, any of a punched metal, a nonwoven fabric, a foamed metal, an expanded metal, a porous metal foil formed by electroforming, and a so-called woven mesh formed by knitting a metal wire can be used.

(Reverse current absorption layer)
A material having an oxidation-reduction potential lower than the oxidation-reduction potential of the element for the cathode catalyst layer described above can be selected as the material for the reverse current absorption layer. Examples include nickel and iron.

(Current collector)
The cathode chamber 70 preferably includes the current collector 23. Thereby, the current collection effect is enhanced. In the present embodiment, the current collector 23 is a perforated plate, and is preferably disposed substantially parallel to the surface of the cathode 21.

  The current collector 23 is preferably made of an electrically conductive metal such as nickel, iron, copper, silver, and titanium. The current collector 23 may be a mixture, alloy or composite oxide of these metals. Note that the shape of the current collector 23 may be any shape as long as it functions as a current collector, and may be a plate shape or a net shape.

(Metal elastic body)
By installing the metal elastic body 22 between the current collector 23 and the cathode 21, each cathode 21 of the plurality of electrolytic cells 50 connected in series is pressed against the cation exchange membrane 51, and The distance between each cathode 21 is shortened, and the voltage applied to the plurality of electrolytic cells 50 connected in series can be reduced. By reducing the voltage, power consumption can be reduced. In addition, by installing the metal elastic body 22, when the laminate including the electrode for electrolysis according to the present embodiment is installed in the electrolytic cell, the electrode for electrolysis is stabilized by the pressing pressure of the metal elastic body 22. Can be kept in place.

  As the metal elastic body 22, a spring member such as a spiral spring or a coil, a cushioning mat or the like can be used. As the metal elastic body 22, a suitable material can be appropriately adopted in consideration of a stress or the like pressing the ion exchange membrane. The metal elastic body 22 may be provided on the surface of the current collector 23 on the cathode chamber 70 side, or may be provided on the surface of the partition wall on the anode chamber 60 side. Usually, since both chambers are partitioned so that the cathode chamber 70 is smaller than the anode chamber 60, the metal elastic body 22 is placed between the current collector 23 of the cathode chamber 70 and the cathode 21 from the viewpoint of the strength of the frame. Is preferably provided. The metal elastic body 23 is preferably made of a metal having electrical conductivity, such as nickel, iron, copper, silver, and titanium.

(Support)
The cathode chamber 70 preferably includes a support 24 that electrically connects the current collector 23 and the partition 80. As a result, current can flow efficiently.

  The support 24 is preferably made of an electrically conductive metal such as nickel, iron, copper, silver, and titanium. The shape of the support 24 may be any shape as long as it can support the current collector 23, and may be a bar, a plate, or a net. The support 24 has, for example, a plate shape. The plurality of supports 24 are arranged between the partition wall 80 and the current collector 23. The plurality of supports 24 are arranged so that their surfaces are parallel to each other. The support 24 is disposed substantially perpendicular to the partition 80 and the current collector 23.

(Anode gasket, cathode gasket)
The anode-side gasket is preferably arranged on the surface of the frame forming the anode chamber 60. The cathode side gasket is preferably arranged on the surface of the frame constituting the cathode chamber 70. The electrolytic cells are connected to each other such that the anode gasket included in one electrolytic cell and the cathode gasket of the electrolytic cell adjacent thereto sandwich the cation exchange membrane 51 (see FIGS. 9 and 10). With these gaskets, when a plurality of electrolytic cells 50 are connected in series via the cation exchange membrane 51, airtightness can be imparted to the connection points.

  The gasket seals between the ion exchange membrane and the electrolytic cell. Specific examples of the gasket include a frame-shaped rubber sheet having an opening formed in the center. The gasket is required to have resistance to a corrosive electrolytic solution and generated gas and to be usable for a long period of time. Therefore, from the viewpoints of chemical resistance and hardness, vulcanized products of ethylene-propylene-diene rubber (EPDM rubber) and ethylene-propylene rubber (EPM rubber) and peroxide crosslinked products are usually used as gaskets. If necessary, use a gasket in which the area that comes into contact with the liquid (the liquid contact part) is coated with a fluororesin such as polytetrafluoroethylene (PTFE) or tetrafluoroethylene / perfluoroalkylvinyl ether copolymer (PFA). Can also. These gaskets only need to have openings so as not to hinder the flow of the electrolytic solution, and their shapes are not particularly limited. For example, a frame-shaped gasket is attached with an adhesive or the like along the periphery of each opening of the anode chamber frame forming the anode chamber 60 or the cathode chamber frame forming the cathode chamber 70. Then, for example, when two electrolytic cells 50 are connected via the cation exchange membrane 51 (see FIG. 10), the respective electrolytic cells 50 to which the gaskets are attached via the cation exchange membrane 51 may be tightened. Thus, leakage of the electrolytic solution, alkali metal hydroxide generated by electrolysis, chlorine gas, hydrogen gas, and the like to the outside of the electrolytic cell 50 can be suppressed.

(Cation exchange membrane 51)
The cation exchange membrane 51 is as described above in the section of the ion exchange membrane.

(Water electrolysis)
In the electrolytic cell of the present embodiment, the electrolytic cell in the case of performing water electrolysis has a configuration in which the ion exchange membrane in the electrolytic cell in the case of performing the above-described salt electrolysis is changed to a microporous membrane. Further, this is different from the electrolytic cell in the case of performing the above-described salt electrolysis in that the raw material to be supplied is water. With respect to other configurations, the same configuration as the electrolytic bath in the case of performing salt electrolysis can be adopted for the electrolytic bath in the case of performing the water electrolysis. In the case of salt electrolysis, titanium gas is used as the material of the anode chamber because chlorine gas is generated in the anode chamber, but in the case of water electrolysis, only oxygen gas is generated in the anode chamber. The same material can be used. For example, nickel and the like can be mentioned. As the anode coating, a catalyst coating for generating oxygen is suitable. Examples of catalyst coatings include metals of the platinum and transition metals, oxides, hydroxides, and the like. For example, elements such as platinum, iridium, palladium, ruthenium, nickel, cobalt, and iron can be used.

  The present embodiment will be described in more detail with reference to the following examples and comparative examples, but the present embodiment is not limited to the following examples.

(Diaphragm used in Examples and Comparative Examples)
The ion exchange membrane A manufactured as follows was used as a diaphragm used for manufacturing a laminate.
As the reinforcing core material, a 90-denier monofilament made of polytetrafluoroethylene (PTFE) was used (hereinafter, referred to as PTFE yarn). As the sacrificial yarn, a yarn obtained by twisting 35 denier, 6-filament polyethylene terephthalate (PET) with a twist of 200 times / m was used (hereinafter referred to as PET yarn). First, in each of the TD and MD directions, plain weave was performed so that 24 PTFE yarns / inch and two sacrificial yarns were arranged between adjacent PTFE yarns to obtain a woven fabric. The obtained woven fabric was pressure-bonded with a roll to obtain a reinforcing material as a woven fabric having a thickness of 70 μm.
Next, dry resins A and CF which are copolymers of CF ₂ = CF ₂ and CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ COOCH ₃ and have an ion exchange capacity of 0.85 mg equivalent / g. Resin B as a dry resin having a copolymer of ₂ = CF ₂ and CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ SO ₂ F having an ion exchange capacity of 1.03 mg equivalent / g was prepared.
Using these resins A and B, a two-layer film X having a resin A layer thickness of 15 μm and a resin B layer thickness of 84 μm was obtained by co-extrusion T-die method. Further, a single-layer film Y having a thickness of 20 μm was obtained using only the resin B by a T-die method.
Subsequently, on a hot plate having a heating source and a vacuum source inside and having fine holes on its surface, release paper (conical embossing with a height of 50 μm), film Y, reinforcing material and film X in this order. After laminating and heating and decompressing for 2 minutes at a hot plate surface temperature of 223 ° C. and a degree of decompression of 0.067 MPa, a release film was removed to obtain a composite film. The film X was laminated so that the resin B was on the lower surface.
The obtained composite membrane was saponified by immersing it in an aqueous solution containing 30% by mass of dimethyl sulfoxide (DMSO) and 15% by mass of potassium hydroxide (KOH) at 80 ° C. for 20 minutes. Thereafter, the substrate was immersed in an aqueous solution containing 0.5 N of sodium hydroxide (NaOH) at 50 ° C. for 1 hour to replace the counter ion of the ion exchange group with Na, and then washed with water. Thereafter, the surface of the resin B side was polished by setting the relative speed between the polishing roll and the film to 100 m / min and the pressing amount of the polishing roll to 2 mm to form an opening, and then dried at 60 ° C.
Further, 20% by mass of zirconium oxide having a primary particle diameter of 1 μm was added to a 5% by mass solution of an acid-type resin of resin B in ethanol to prepare a dispersed suspension. Spraying was performed on both surfaces of the membrane to form a coating of zirconium oxide on the surface of the composite membrane, thereby obtaining an ion exchange membrane A as a diaphragm.
The coating density of zirconium oxide was measured by X-ray fluorescence measurement and found to be 0.5 mg / cm ² . Here, the average particle size was measured by a particle size distribution meter (“SALD (registered trademark) 2200” manufactured by Shimadzu Corporation).

(Measurement of electrode thickness)
Using a Digimatic Sixness Gauge (manufactured by Mitutoyo Corporation, minimum display 0.001 mm), the average value of 10 points measured uniformly over the surface was calculated.

(Electrolysis evaluation)
The electrolysis performance was evaluated by the following electrolysis experiments.
A titanium anode cell having an anode chamber provided with an anode and a cathode cell having a nickel cathode chamber provided with a cathode faced each other. A pair of gaskets was placed between the cells. The ion exchange membrane A was sandwiched between a pair of gaskets. Then, the anode cell, the gasket, the ion exchange membrane A, the gasket and the cathode were brought into close contact with each other to obtain an electrolytic cell, and an electrolytic cell containing the cell was prepared.
The anode was produced by applying a mixed solution of ruthenium chloride, iridium chloride and titanium tetrachloride on a titanium substrate which had been blasted and acid-etched as a pretreatment, dried and fired. The anode was fixed to the anode chamber by welding.
A nickel expanded metal was used as a current collector in the cathode chamber. The size of the current collector was 95 mm long × 110 mm wide. As the metal elastic body, a mattress knitted with a fine nickel wire was used. A mattress, which is a metal elastic body, was placed on the current collector. A mesh cathode prepared by applying a mixed solution of ruthenium and cerium to a nickel mesh on which a nickel wire having a diameter of 150 μm was plain-woven with a mesh opening of 40 mesh, dried and fired was placed. The thickness of the coated cathode was 310 μm. The four corners of the cathode were fixed to the current collector with a string made of Teflon (registered trademark).
This electrolytic cell has a zero-gap structure utilizing the repulsive force of a mattress which is a metal elastic body. As the gasket, a rubber gasket made of EPDM (ethylene propylene diene) was used.
Electrolysis of salt was performed using the above electrolytic cell. The salt water concentration (sodium chloride concentration) in the anode chamber was adjusted to 205 g / L. The concentration of sodium hydroxide in the cathode compartment was adjusted to 32% by mass. Each temperature of the anode chamber and the cathode chamber was adjusted such that the temperature in each electrolytic cell became 90 ° C. Salt electrolysis was performed at a current density of 6 kA / m ² , and the voltage and current efficiency were measured. Here, the current efficiency is the ratio of the amount of generated caustic soda to the flowing current, and when the flowing current causes impurity ions or hydroxide ions, not sodium ions, to move through the ion exchange membrane, the current Efficiency decreases. The current efficiency was obtained by dividing the number of moles of caustic soda generated in a certain period of time by the number of moles of electrons of the current flowing during that time. The number of moles of caustic soda was determined by collecting caustic soda generated by electrolysis in a plastic tank and measuring its mass.

<Observation of ion exchange membrane after electrolysis test>
The state of the ion exchange membrane A after the electrolytic test was confirmed as follows.
First, the appearance of the surface portion of the ion exchange membrane A corresponding to the portion where the electrode thickness was increased by the repair (the portion where the existing electrode and the repair electrode for electrolysis overlap) was observed. If necessary, the coating applied to the surface was removed using a brush or the like. In the appearance observation, the ion exchange membrane A was examined for whitening and discoloration.
Next, the surface portion of the above-mentioned ion exchange membrane A was cut at five locations at equal intervals, and the exposed membrane cross section was observed with a macroscope and SEM. The presence or absence of peeling and blistering on the surface and inside of the film (hereinafter, also simply referred to as “film damage”) was confirmed, and if it occurred, the number was counted.

(Example 1)
The electrode for electrolysis used for repair was prepared as follows.
A nickel foil having a gauge thickness of 22 μm was prepared. One surface of this nickel foil was subjected to a surface roughening treatment by nickel plating.
The arithmetic average roughness Ra of the roughened surface was 0.95 μm.
For the surface roughness measurement, a stylus type surface roughness measuring device SJ-310 (Mitutoyo Corporation) was used.
The measurement sample was placed on a surface plate parallel to the ground, and the arithmetic average roughness Ra was measured under the following measurement conditions. When the measurement was performed six times, the average value was described.
<Shape of stylus> Conical taper angle = 60 °, tip radius = 2 μm, static measuring force = 0.75 mN
<Roughness standard> JIS2001
<Evaluation curve> R
<Filter> GAUSS
<Cutoff value λc> 0.8mm
<Cutoff value λs> 2.5 μm
<Number of sections> 5
<Previous run, back run> Yes

A circular hole having a diameter of 1 mm was formed in the nickel foil by punching to form a porous foil. The porosity calculated as follows was 44%.
(Measurement of porosity)
Using an electrode for electrolysis, a digimatic sixness gauge (manufactured by Mitutoyo Corp., minimum display 0.001 mm) was used to calculate an average value obtained by uniformly measuring 10 points in the plane. Using this as the thickness of the electrode (gauge thickness), the volume was calculated. Thereafter, the mass was measured with an electronic balance, and the porosity or porosity was calculated from the specific gravity of the metal (specific gravity of nickel = 8.908 g / cm ³ , specific gravity of titanium = 4.506 g / cm ³ ).
Porosity (porosity) (%) = (1− (electrode mass) / (electrode volume × specific gravity of metal)) × 100

A coating solution for forming an electrode catalyst was prepared according to the following procedure.
A ruthenium nitrate solution having a ruthenium concentration of 100 g / L (Furuya Metal Co., Ltd.) and cerium nitrate (Kishida Chemical Co., Ltd.) were mixed so that the molar ratio of ruthenium element to cerium element was 1: 0.25. This mixture was sufficiently stirred to obtain a cathode coating solution.
At the bottom of the roll coating device, a vat containing the coating solution was installed. Make sure that the coating liquid is always in contact with the coating roll that has a PVC (polyvinyl chloride) tube wrapped with a closed-cell type foamed EPDM (ethylene propylene diene rubber) rubber (INOAC CORPORATION, E-4088, thickness 10 mm). It was installed in. An application roll around which the same EPDM was wound was set on the upper part, and a PVC-made roller was further set thereon.
The coating liquid was applied to the electrode substrate for electrolysis by passing it between the second coating roll and the uppermost roller made of PVC (roll coating method). Thereafter, drying was performed at 50 ° C. for 10 minutes, preliminary firing was performed at 150 ° C. for 3 minutes, and firing was performed at 350 ° C. for 10 minutes. These series of operations of application, drying, preliminary firing, and firing were repeated until a predetermined coating amount was obtained.
The thickness of the produced electrode for electrolysis was 30 μm. The thickness of the catalyst layer containing ruthenium oxide and cerium oxide was 8 μm, respectively, obtained by subtracting the thickness of the electrode substrate for electrolysis from the thickness of the electrode for electrolysis. The coating was also formed on the non-roughened surface.

A hole of 20 mm × 20 mm size was made with precision scissors near the center of a mesh cathode having a length of 95 mm and a width of 110 mm (this was used as a damaged electrode model). An electrode for repair of 40 mm × 40 mm in size for repair (hereinafter also simply referred to as “repair electrode”) was placed so that the damaged portion was exactly at the center, and four corners (four points) were fixed by welding. In this way, the damaged part was repaired. The repair took only a few minutes and was easy.
When the electrolysis evaluation was performed, the electrolysis performance was the same as that when no holes were made, and no film damage was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the existing electrode and the repair electrode overlap after the repair was 340 μm. T2 / T1 = 1.10.

(Example 2)
The repair was performed in the same manner as in Example 1 except that the four sides (outer edge portion) of the repair electrode were fixed with a cyanoacrylate-based adhesive.
The repair took only a few minutes and was easy.
When the electrolysis evaluation was performed, the electrolysis performance was the same as that when no holes were made, and no film damage was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the existing electrode and the repair electrode overlap after the repair was 340 μm. T2 / T1 = 1.10.

(Example 3)
The repair was performed in the same manner as in Example 1 except that the four sides (outer edges) of the repair electrode were fixed by waving with PTFE thread.
The repair took only a few minutes and was easy.
When the electrolysis evaluation was performed, the electrolysis performance was the same as that when no holes were made, and no film damage was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the existing electrode and the repair electrode overlap after the repair was 340 μm. T2 / T1 = 1.10.

(Example 4)
The repair was performed in the same manner as in Example 1 except that a nickel foil having a thickness of 30 μm was used as the repair electrode. The thickness of the repair electrode was 38 μm.
The repair took only a few minutes and was easy.
When the electrolysis evaluation was performed, the electrolysis performance was the same as that when no holes were made, and no film damage was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the existing electrode and the repair electrode overlap after the repair was 348 μm. T2 / T1 = 1.12.

(Example 5)
The repair was performed in the same manner as in Example 1 except that a nickel foil having a thickness of 50 μm was used as the repair electrode. The thickness of the repair electrode was 59 μm.
The repair took only a few minutes and was easy.
When the electrolysis evaluation was performed, the electrolysis performance was the same as that when no holes were made, and no film damage was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the existing electrode and the repair electrode overlap after the repair was 369 μm. T2 / T1 = 1.19.

(Example 6)
The repair was performed in the same manner as in Example 1 except that a nickel foil having a thickness of 10 μm was used as the repair electrode. The thickness of the repair electrode was 16 μm.
The repair took only a few minutes and was easy.
When the electrolysis evaluation was performed, the electrolysis performance was the same as that when no holes were made, and no film damage was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the repaired electrode overlaps the existing electrode after the repair was 326 μm. T2 / T1 = 1.05.

(Example 7)
The repair was performed in the same manner as in Example 1 except that a nickel expanded metal having a thickness of 100 μm was used as the repair electrode. The thickness of the repair electrode was 107 μm.
The repair took only a few minutes and was easy.
When the electrolysis evaluation was performed, the electrolysis performance was the same as that when no holes were made, and no film damage was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the existing electrode and the repair electrode overlap after the repair was 417 μm. T2 / T1 = 1.35.

(Example 8)
The repair was performed in the same manner as in Example 1 except that a nickel expanded metal having a thickness of 150 μm was used as the repair electrode. The thickness of the repair electrode was 157 μm.
The repair took only a few minutes and was easy.
The results of the electrolysis evaluation were the same as the electrolysis performance when no holes were made. In addition, although slight whitening was observed during the appearance observation, no damage was found in the film observation in the cross-section observation, and no problem was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the repaired electrode overlaps the existing electrode after the repair was 467 μm. T2 / T1 = 1.51.

(Example 9)
The repair was performed in the same manner as in Example 1 except that a nickel expanded metal having a thickness of 200 μm was used as the repair electrode. The thickness of the repair electrode was 211 μm.
The repair took only a few minutes and was easy.
The results of the electrolysis evaluation were the same as the electrolysis performance when no holes were made. In addition, although slight whitening was observed during the appearance observation, no damage was found in the film observation in the cross-section observation, and no problem was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the existing electrode and the repair electrode overlap after the repair was 521 μm. T2 / T1 = 1.68.

(Example 10)
The repair was performed in the same manner as in Example 1 except that a nickel expanded metal having a thickness of 250 μm was used as the repair electrode. The thickness of the repair electrode was 260 μm.
The repair took only a few minutes and was easy.
The results of the electrolysis evaluation were the same as the electrolysis performance when no holes were made. In addition, although slight whitening was observed during the appearance observation, no damage was found in the film observation in the cross-section observation, and no problem was observed.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the existing electrode and the repair electrode overlap after the repair was 521 μm. T2 / T1 = 1.68.

(Comparative Example 1)
The repair was performed in the same manner as in Example 1 except that the same electrode as the existing electrode was used as the repair electrode. The thickness of the repair electrode was 320 μm.
The repair took only a few minutes and was easy.
When the electrolysis evaluation was performed, the electrolysis performance was worse than the electrolysis performance when no holes were made. Membrane damage was observed at the location corresponding to the portion raised by welding. Specifically, damage was found in which the end of the unwelded nickel wire penetrated the membrane. Further, a plurality of whitened portions were observed in the appearance observation, and seven film damages were observed in the cross-section observation.
The electrode thickness T1 before the repair was 320 μm, and the thickness T2 of the portion where the repair electrode overlaps the existing electrode after the repair was 640 μm. T2 / T1 = 2.00.

(Comparative Example 2)
The repair was performed in the same manner as in Comparative Example 1 except that the nickel wires were connected by welding and repaired. The number of wires to be welded was 100 or more in total on four sides, and repair took about half a day. Repair of the commercial electrolysis frame was found to be too time consuming and impractical.
The results of the electrolysis evaluation were the same as the electrolysis performance when no holes were made.

(Comparative Example 3)
The repair was performed in the same manner as in Example 1 except that a nickel expanded metal having a thickness of 500 μm was used as the base material as the repair electrode. The thickness of the repair electrode was 508 μm.
The repair took only a few minutes and was easy.
When the electrolysis evaluation was performed, the electrolysis voltage increased by 2% and the current efficiency deteriorated by 0.5% from the electrolysis performance when no holes were formed. In addition, a number of whitened portions were observed in the external appearance observation, and in the cross-sectional observation, film breakage and film damage originating from the end of the repair electrode were observed in ten places.
The electrode thickness T1 before the repair was 310 μm, and the thickness T2 of the portion where the existing electrode and the repair electrode overlap after the repair was 818 μm. T2 / T1 = 2.64.

Description of reference numerals for FIG. 1 10 ... electrode electrode base material, 20 ... first layer covering the base material, 30 ... second layer, 101 ... electrode electrode

Description of reference numerals for FIG. 2 1 ... Ion exchange membrane, 1a ... Membrane body, 2 ... Carboxylic acid layer, 3 ... Sulfonic acid layer, 4 ... Reinforced core material, 11a, 11b ... Coating layer

Description of reference numerals for FIG. 3 21a, 21b ... reinforced core material

Description of reference numerals for FIGS. 4 (a) and 4 (b) 52: reinforcing yarn, 504: communication hole, 504a: sacrifice yarn

Description of reference numerals for FIGS. 5 to 8 101: Electrode for electrode, 101a: Metal wire extending from the end of the electrode for electrolysis, 102: Existing electrode, 102a: Cut portion of the existing electrode.

Description of reference numerals for FIG. 9 to FIG.
11 ... anode, 12 ... anode gasket, 13 ... cathode gasket,
18: reverse current absorber, 18a: base material, 18b: reverse current absorption layer, 19: bottom of anode chamber,
Reference numeral 21: cathode, 22: metal elastic body, 23: current collector, 24: support,
50 ... electrolysis cell, 60 ... anode compartment, 51 ... ion exchange membrane (diaphragm), 70 ... cathode compartment,
80 ... partition walls, 90 ... cathode structure for electrolysis

Claims (7)

A method for manufacturing a new electrode by repairing the surface of an existing electrode,
A method for manufacturing an electrode, comprising: a step (A) of fixing an electrode for electrolysis having a thickness of 315 μm or less to at least one region of the surface of the existing electrode.   The method for manufacturing an electrode according to claim 1, wherein in the region, at least a part of the electrode for electrolysis is fixed so as to penetrate the existing electrode.   The method for manufacturing an electrode according to claim 1, wherein in the region, at least a part of the electrode for electrolysis is positioned and fixed inside the existing electrode.   The method for producing an electrode according to any one of claims 1 to 3, further comprising a fixing member for fixing the existing electrode and the electrode for electrolysis.   The method for producing an electrode according to claim 1, wherein in the step (A), water is interposed between the electrode for electrolysis and the existing electrode.   The ratio of the electrode thickness T1 before the repair of the existing electrode to the electrode thickness T2 after the repair is 1.0 to less than 2.1 as T2 / T1. Manufacturing method of electrode.   The method for producing an electrode according to any one of claims 1 to 6, wherein the electrode for electrolysis has a punched shape, an expanded shape, or a mesh shape.