Anion exchange membrane roll article

Abstract

This anion exchange membrane roll article comprises a roll of an anion exchange membrane containing water, and an exterior material covering the roll of the anion exchange membrane, wherein: the anion exchange membrane has a ratio of the moisture content MC to the saturated moisture content SC at 20ºC of 10-50%; the exterior material has a water vapor permeability of at most 100 g / (m2∙day) at a temperature of 40ºC and a relative humidity of 90%; and the roll of the anion exchange membrane is sealed on the inner peripheral side from the exterior material.

Description

Anion exchange membrane roll product

[0001] The present invention relates to an anion exchange membrane used in the field of green hydrogen utilization for water electrolysis, and more particularly to a rolled article of an anion exchange membrane that can reduce quality defects during storage and transportation.

[0002] Water electrolysis can be broadly divided into alkaline water electrolysis (AWE), proton exchange membrane (PEM) water electrolysis, anion exchange membrane (AEM) water electrolysis, and solid oxide electrolysis (SOEC) water electrolysis. Unlike anion exchange membranes used for other applications, anion exchange membranes used in water electrolysis must be used in a wet (swollen) state containing water to electrolyze water. Therefore, anion exchange membranes for water electrolysis inevitably undergo dimensional changes between dry and wet states. Unlike general plastic films, anion exchange membranes for water electrolysis are not manufactured using thermal processing methods such as the calendaring method or T-die method. Therefore, they are less susceptible to the effects of ambient temperature changes and thermal shrinkage due to thermal relaxation after processing. Therefore, the dimensions of anion exchange membranes for water electrolysis depend primarily on the moisture content of the membrane.

[0003] JP 2018-35315 A JP 2013-203458 A

[0004] Anion exchange membranes are often shipped in a dry state during the product shipping process, and transporting them in a dry state is cost-effective because it reduces weight.

[0005] However, unlike ordinary plastic rolls, when a dry roll is placed in a high-humidity environment (i.e., when the moisture content of the roll increases), the membrane gradually absorbs moisture, causing the membrane to expand in both length and width. The increase in length causes the roll to loosen, resulting in sagging, misalignment, and waviness. The increase in width also causes uneven edges and wrinkles.

[0006] Conversely, if a wet roll is placed in a low-humidity environment (i.e., when the moisture content of the roll decreases), the membrane gradually dries out, causing the membrane to shrink in both its length and width. This can lead to various quality problems, such as tightness of the roll, curvature of the membrane, and adhesion between membranes. Furthermore, in natural environments, even indoors, humidity fluctuates, causing anion exchange membranes to repeatedly expand and contract in size. When anion exchange membranes are rolled, changes in external humidity (or a history of changes) that exceed the internal distortion tolerance of the roll can adversely affect the roll quality, as described above. Because the degree of influence of external humidity differs between the outer and inner parts of the roll, sudden humidity changes in nature can severely damage the roll.

[0007] Patent Document 1 discloses a method of storing industrial polyamide films in a sealed packaging container while preventing the film from changing its shape due to moisture absorption.

[0008] Furthermore, Patent Document 2 discloses a packaging body that prevents moisture absorption during storage of a film roll made by winding up a polyester film in a roll shape.

[0009] However, rolls of anion exchange membranes are far more hygroscopic than ordinary resin films and are prone to dimensional changes, so there is still room for improvement in the optimum configuration and method for storing and transporting them.

[0010] The present inventors have conducted extensive research into a solution to the above-described problem in view of the particular nature of dimensional changes in anion exchange membranes used in water electrolysis. As a result, they have found that by producing a roll adjusted to a specific moisture content and sealing it in an exterior material with water vapor barrier properties to reduce changes in the humidity environment, it is possible to significantly reduce defects in the quality of the roll and membrane during storage, transportation, and use after opening, and have completed the present invention.

[0011] Specifically, the gist of the present invention relates to the following [1] to

[10] . [1] An anion exchange membrane roll product, the anion exchange membrane roll product comprising: a roll of an anion exchange membrane containing water; and an exterior material covering the roll of the anion exchange membrane, wherein the ratio of the water content MC to the saturated water content SC of the anion exchange membrane at 20°C is 10% or more and 50% or less, and the exterior material has a water vapor permeability of 100 g / (m ２ An anion exchange membrane roll product, wherein the anion exchange membrane roll is sealed on the inner circumferential side of the exterior material. [2] The anion exchange membrane roll product according to [1], wherein the anion exchange membrane has a moisture content MC of 5% by mass or more and 25% by mass or less. [3] The anion exchange membrane roll product according to [1] or [2], wherein the anion exchange membrane has a saturated moisture content SC of 25% by mass or more and 100% by mass or less. [4] The anion exchange membrane roll product according to any of [1] to [3], wherein the exterior material is formed of at least one film selected from the group consisting of a polyethylene film, a polypropylene film, and a polyethylene terephthalate film. [5] The anion exchange membrane roll product according to any of [1] to [4], further comprising a core material that forms a central axis of the anion exchange membrane roll, wherein the core material is made of plastic. [6] The anion exchange membrane roll product according to any of [1] to [5], wherein 90% or more of the counter ions of the anion exchange membrane are bicarbonate ions. [7] The anion exchange membrane roll product according to any one of [1] to [6], wherein the exterior material has a tensile modulus of elasticity of 1 MPa or more and 3000 MPa or less. [8] The anion exchange membrane roll product according to any one of [1] to [7], further comprising an interior material, wherein the interior material covers the anion exchange membrane roll and is located more inward than the exterior material. [9] The anion exchange membrane roll product according to [8], wherein the interior material is formed of at least one film selected from the group consisting of a polyethylene film, a polypropylene film, and a polyethylene terephthalate film.

[10] The anion exchange membrane roll product according to [8] or [9], wherein the interior material has a tensile modulus of elasticity of 10 MPa or more and 6000 MPa or less.

[0012] The anion exchange membrane roll article according to one embodiment of the present invention can reduce the risk of quality defects occurring when storing or transporting anion exchange membranes for water electrolysis.

[0013] FIG. 1 is a perspective view schematically illustrating an example of an anion exchange membrane roll.

[0014] An anion exchange membrane roll product according to one embodiment of the present invention will be described in detail below. The embodiments described below are presented as preferred examples of implementing the present invention, and while some specific technical features are provided, please note that the technical scope of the present invention is not limited to these specific aspects. In the following description, "A to B" for numerical values ​​A and B means "A or greater and B or less" unless otherwise specified. Furthermore, when numerical ranges are described in stages, the upper and lower limits of each numerical range can be arbitrarily combined. In this specification, the expression "A or B" can be interpreted as "at least one selected from the group consisting of A and B."

[0015] [Anion Exchange Membrane] Fig. 1 is a perspective view schematically illustrating an example of an anion exchange membrane roll. The anion exchange membrane roll shown in Fig. 1 is stored and transported in a roll state in which an anion exchange membrane 2A is wound around a core material B as a central axis. An inner material or outer material C may be present on the outer periphery of the anion exchange membrane 2A. Wa represents the width direction length of the anion exchange membrane 2A, and Wc represents the width direction length of the inner material or outer material C.

[0016] An anion exchange membrane roll product according to one embodiment of the present invention includes a roll of an anion exchange membrane. The anion exchange membrane contains water. The anion exchange membrane itself is not particularly limited in its composition, but typical anion exchange membranes for water electrolysis are crosslinked polymer membranes that primarily contain polymers polymerized from hydrocarbon monomers and have functional groups with anion exchange function. Examples of anion exchange membranes include resin membranes in which cationic groups are introduced into a copolymer of chloromethylstyrene and divinylbenzene (or a terpolymer with styrene added in some cases) by chemically reacting it with a quaternary ammonium salt as a post-treatment, and resin membranes in which vinylbenzyltrimethylammonium salt is copolymerized with divinylbenzene or the like.

[0017] Examples of chemical substances with anion exchange function include those containing at least one structural unit selected from the group consisting of imidazole, imidazolium, and piperidine. Porous resin materials such as polyethylene, polypropylene, and polyvinyl chloride can also be used as the substrate of these anion exchange membranes.

[0018] The polymerization method for obtaining the above-mentioned polymer may be a known polymerization method such as a cast method, a roll method, a batch method, etc. The polymerization method may be a known method such as photopolymerization, thermal polymerization, ionic polymerization, etc.

[0019] Counterions of anion exchange membranes include at least one anion selected from the group consisting of chloride ions, hydroxide ions, and bicarbonate ions, but are not particularly limited in the present invention. However, when anion exchange membranes are exposed to a gas atmosphere containing carbon dioxide, such as air, they gradually convert to bicarbonate ions, so it is desirable to prepare them in advance as bicarbonate ions. In the bicarbonate ion form, the saturated water content of the membrane can be relatively high, thereby widening the tolerance range for humidity changes to prevent condensation. Preferably, 90% or more of the counter ions of anion exchange membranes are bicarbonate ions, more preferably 95% or more, and even more preferably 99% or more. Immersing an anion exchange membrane in a solution containing bicarbonate ions, such as an aqueous potassium bicarbonate solution, can exchange the counter ions for bicarbonate ions. The proportion of bicarbonate ions in the total counter ions can be measured by titration, calculating the difference between the titer when all counter ions are halogen and the titer after exchange with bicarbonate ions.

[0020] The thickness of the anion exchange membrane is preferably in the range of 10 to 75 μm in a dry state and 12 to 90 μm in a state where the membrane is sufficiently swollen in water (for example, after immersion for 15 minutes or more). The properties required of an anion exchange membrane for water electrolysis are advantageously low electrical resistance in the thickness direction and low hydrogen crossover. A membrane thinner than the above upper limit reduces the electrical resistance, whereas a membrane thicker than the above lower limit makes hydrogen crossover less likely to occur, which are preferred.

[0021] Hydrogen crossover is a phenomenon in which hydrogen generated on the cathode side of a water electrolysis device permeates the anion exchange membrane and emerges on the anode side, and is more likely to occur when the hydrogen pressure on the cathode side is high. The occurrence of hydrogen crossover is generally confirmed by measuring the hydrogen concentration on the anode side using gas chromatography. Because oxygen is mainly generated at the anode of a water electrolysis device, if hydrogen mixes with the anode side due to hydrogen crossover, it could result in an explosive mixture.

[0022] In an anion exchange membrane according to one embodiment of the present invention, the ratio of the water content MC to the saturated water content SC of the anion exchange membrane (MC / SC, hereinafter also referred to as the "wetness ratio") in a 20°C environment is 10% or more and 50% or less. An anion exchange membrane with a wetness ratio of 100% is an anion exchange membrane in a saturated water-containing state. An anion exchange membrane with a wetness ratio of 0% is an anion exchange membrane in a completely dry state. An anion exchange membrane with a wetness ratio of 10% or more and 50% or less has an appropriate amount of water and is in a partially dry state. The wetness ratio is preferably 15% or more and 40% or less, and more preferably 17% or more and 37% or less. The wetness ratio (%) is a percentage obtained by dividing the water content MC of the anion exchange membrane by the saturated water content SC of the anion exchange membrane, which will be described later. The water content MC of an anion exchange membrane is one of the indicators that indicates the mass of water contained in the anion exchange membrane relative to its mass in a dry state (hereinafter also referred to as the "dry membrane mass").

[0023] When the anion exchange membrane has a moisture content of at least a certain level, it is less likely to absorb moisture from the air, making it less likely to loosen, thereby preventing quality defects in the anion exchange membrane roll. Conversely, when the moisture content is below a certain level, the roll is less likely to tighten when taken out into an environment with a normal humidity range, preventing quality defects in the anion exchange membrane roll. The above moisture content is close to equilibrium with the normal humidity range in temperate zones (RH 40-90%). Therefore, by adjusting the roll to the above moisture content and then sealing it with an exterior material, deterioration in the quality of the anion exchange membrane roll can be prevented even when the roll is stored and transported, and then opened in a workplace with a normal humidity environment and installed in a hydrogen generator. Note that sealing the roll with an exterior material means that the roll is covered with the exterior material with substantially no gaps so as to isolate the roll from the outside air. However, it is not necessary for the exterior material to be completely isolated from the outside air, as long as it can inhibit the intrusion of moisture, water, etc. to an extent that the effects of the present invention can be achieved.

[0024] A method for measuring the moisture content MC of an anion exchange membrane according to the present disclosure will now be described. A sample of a predetermined area (e.g., 10 cm x 10 cm) is cut from a roll of anion exchange membrane, and the mass (w1) of the sample is measured in a room at room temperature of 20°C and relative humidity (RH) of 50%. The sample is then dried at 60°C in a vacuum for 5 hours, and its mass is measured in a room at room temperature of 20°C and RH of 30%, which is the dry mass (w2). The moisture content MC of the anion exchange membrane is calculated according to the following formula (1): MC (mass%) = (w1 - w2) / w2 x 100 (1) These mass measurement procedures are affected by the ambient humidity and should be carried out quickly in a short period of time.

[0025] From the viewpoint of easily adjusting the moisture content within a suitable range, the moisture content MC of the anion exchange membrane is preferably 5 to 25% by mass. More preferably, it is 7 to 17% by mass. If the temperature and humidity environment during use is known, the moisture content may be adjusted more strictly depending on the usage environment, because the anion exchange membrane roll will dry less and absorb less moisture when opened and used if it is sealed in a similar environment in advance. The moisture content MC can be controlled, for example, by drying the anion exchange membrane roll after production with hot air or by adjusting the temperature and humidity of the production and winding environment.

[0026] The saturated water content (SC) of an anion exchange membrane is an index indicating the maximum amount of water that the anion exchange membrane can contain. From the viewpoint of improving ion exchange performance, the saturated water content (SC) of the anion exchange membrane is preferably 20% by mass or more, more preferably 23% by mass or more, and even more preferably 25% by mass or more. The saturated water content (SC) may be 30% by mass or more, or may be 40% by mass or more. From the viewpoint of improving the mechanical strength of the anion exchange membrane, the saturated water content (SC) is preferably 120% by mass or less, more preferably 110% by mass or less, and even more preferably 105% by mass or less. The saturated water content (SC) may be 70% by mass or less, 60% by mass or less, or 55% by mass or less. The saturated water content (SC) of the anion exchange membrane may be 25 to 100% by mass, 30 to 70% by mass, or 40 to 55% by mass. The saturated water content SC can be increased by increasing the amount of hydrophilic functional groups in the composition of the anion exchange membrane, and can be decreased by increasing the amount of hydrophobic functional groups.

[0027] The saturated moisture content SC of an anion exchange membrane is measured by the following method. A sample of a predetermined area (e.g., 10 cm x 10 cm) is cut out from a roll of anion exchange membrane, and after sufficient swelling in water (e.g., by immersion for 15 minutes or more), the mass (w3) of the sample is measured in a room at room temperature of 20°C and a relative humidity of 30% RH. The sample is then dried in a vacuum at 60°C for 5 hours, and the mass (w4) is measured in a room at RH 30%. The saturated moisture content SC of the anion exchange membrane is calculated according to the following formula (2): SC (mass%) = (w3 - w4) / w4 x 100 (2)

[0028] [Anion Exchange Membrane Roll] The anion exchange membrane according to one embodiment of the present invention is stored and transported in the form of a wound product, i.e., a roll (hereinafter also referred to as an "anion exchange membrane roll"). The winding length (referring to the length of the long side of the anion exchange membrane constituting the anion exchange membrane roll) is preferably in the range of 100 to 10,000 m. 200 to 600 m is more preferable. When the winding length is 100 m or more, the volume and mass ratio occupied by the core material (described later) are not too large, which is preferable from the viewpoint of storage and transport efficiency. Furthermore, when the winding length is 10,000 m or less, the impact of dimensional changes in the membrane in the length direction on roll quality is reduced, making it easier to maintain roll quality.

[0029] The width of the anion exchange membrane roll is preferably in the range of 50 to 2000 mm. 200 to 1000 mm is more preferable. When the width of the anion exchange membrane roll is 2000 mm or less, the impact of dimensional changes in the width direction of the anion exchange membrane on the quality of the anion exchange membrane roll is reduced. Therefore, the width of the anion exchange membrane roll is preferably 2000 mm or less. On the other hand, a roll width of 50 mm or more is preferred in terms of practical size in water electrolysis devices, etc. The anion exchange membrane according to one embodiment of the present invention can be suitably used for water electrolysis, and for water electrolysis applications, the anion exchange membrane has an ion exchange capacity of 1.8 to 3.0 mol / g based on the dry membrane mass of the ion exchange membrane and a membrane resistance of 1.0 Ωcm. ２ The following are preferably used:

[0030] [Exterior Material] In the anion exchange membrane roll product according to one embodiment of the present invention, the anion exchange membrane roll has a water vapor permeability of 100 g / (m) at a temperature of 40° C. and a relative humidity of 90% so that humidity changes in the vicinity of the anion exchange membrane roll are unlikely to occur. ２ The packaging material has a water vapor permeability of 100 g / (m at a temperature of 40°C and a relative humidity of 90%. ２ ·day) or less means that the packaging material has water vapor barrier properties. A packaging material with water vapor barrier properties is capable of packaging rolls and has a water vapor permeability of 100 g / (m) at a temperature of 40°C and a relative humidity of 90%. ２The water vapor permeability of the exterior material at a relative humidity of 90% is not particularly limited as long as it is a material with a water vapor permeability of 90 g / (m ２ ·day) or less, and ２ There is no particular lower limit for the water vapor permeability, but in one example it is the measurement limit, and in another example it is 1 g / (m ２ ・day) or more.

[0031] The water vapor permeability of the exterior material at a temperature of 40°C and a relative humidity of 90% is, for example, 0 to 100 g / (m ２ ·day), and 1 to 100 g / (m ２ · day), and 0 to 90 g / (m ２ ·day), and 1 to 90 g / (m ２ ·day), and 0 to 50 g / (m ２ ·day), and 1 to 50 g / (m ２ ・day).

[0032] The water vapor transmission rate (WVTR) is, for example, g / (m ２ It is expressed in units of 1 m ２ WVTR refers to the mass (g) of water vapor that permeates a membrane (exterior material) of this type in 24 hours (1 day). The WVTR value is measured at 40°C using a Mocon W700 measuring device in accordance with ASTM F1249-06, at a relative temperature of 100% on one main surface of a sample piece cut out of an exterior material to a predetermined size, and at a relative humidity of 0% on the other main surface corresponding to the one main surface. In the present disclosure, the size of the sample piece used for the measurement is 5 cm ２ However, if the WVTR of the measurement sample is high and the sensor is exposed to water, the ２ The measurement was performed by covering a portion of the sample piece to provide a smaller surface area.

[0033] Examples of materials with water vapor barrier properties include specific plastics or metals, or materials laminated, coated, or vapor-deposited with these. From the viewpoint of ease of sealing by heat fusion, plastic film (or a plastic film surface) is most desirable. The exterior material is preferably formed of at least one material selected from the group consisting of polyethylene film (PE), polypropylene film (PP), and polyethylene terephthalate film (PET). A laminated film such as PE / paper / PE may also be used. Furthermore, the metal material may be an alloy such as stainless steel, and in this case, it may be used in the form of a can, for example.

[0034] The tensile modulus of the packaging material is preferably 1 MPa or more and 3000 MPa or less. The packaging material preferably has supple elasticity, i.e., does not have much stiffness. The tensile modulus is an index of the stiffness of the film, and the magnitude of this value correlates with the degree of stiffness. A packaging material that does not have stiffness can easily conform to the shape of the roll of the anion exchange membrane, and can therefore better block outside air. The tensile modulus is more preferably 2 MPa or more and 1500 MPa or less. The method for measuring the tensile modulus follows the measurement method specified in Japanese Industrial Standard JIS K7161-1.

[0035] When the packaging material is a plastic film, the thickness of the packaging material is preferably 5 to 1,000 μm, more preferably 10 to 500 μm, and even more preferably 15 to 250 μm, from the viewpoint of both ease of handling and tear resistance. When the packaging material is metallic, the thickness is, for example, preferably 0.05 to 5.00 mm, and more preferably 0.10 to 1.00 mm.

[0036] The wrapped roll may be further secured in a wooden box or the like for transportation.

[0037] [Regarding the packaging configuration and core material of the roll] When an anion exchange membrane roll is stored in a warehouse, it may be subject to drastic temperature and humidity changes due to weather, etc. Furthermore, when transported by vehicle, ship, or aircraft, it may be exposed to an external environment with high temperatures exceeding 40°C or low temperatures below 0°C, or high humidity of over 90% or low humidity of below 10%. Even under such conditions, the anion exchange membrane roll is sealed with a water vapor barrier packaging material to minimize humidity changes near the anion exchange membrane roll. In the present disclosure, a configuration in which an anion exchange membrane roll is sealed with a packaging material is also referred to as an "anion exchange membrane roll product."

[0038] Methods for sealing the anion exchange membrane roll with the above-mentioned exterior material include heat fusion, adhesion with an adhesive, and fitting.

[0039] When the anion exchange membrane roll is sealed in the packaging material, it is preferable that air is contained between the packaging material and the anion exchange membrane roll. That is, if the anion exchange membrane roll is sealed in the packaging material while a vacuum is created between the packaging material and the anion exchange membrane roll, pressure is applied to the anion exchange membrane, which tends to deteriorate the quality of the anion exchange membrane roll or the anion exchange membrane. Therefore, an environment containing a moderate amount of air or inert gas and maintaining humidity inside the barrier packaging material is preferable. When the anion exchange membrane roll is enclosed in the packaging material, the room temperature is preferably 0°C or higher and 40°C or lower, and the room relative humidity is preferably 10% or higher and 80% or lower, and more preferably 20% or higher and 70% or lower. The relative humidity inside the packaging material immediately after packaging is preferably 15% or higher and 75% or lower, and more preferably 25% or higher and 65% or lower. The relative humidity inside the packaging material can be measured, for example, using a temperature and humidity logger manufactured by Hioki E.E. Corporation.

[0040] The anion exchange membrane roll product may further include a core material around which the anion exchange membrane is wound. This core material serves as the central axis of the anion exchange membrane roll. It is preferable to use a core material with low hygroscopicity for the anion exchange membrane roll. The core material may be made of metal, but lighter plastic is preferable. Known plastic cores include core materials made primarily of acrylonitrile-butadiene-styrene copolymer (ABS), polypropylene (PP), polyethylene (PE), etc. When using a hygroscopic material (e.g., paper), it is preferable to use a core material that has been previously conditioned in a temperature and humidity environment similar to that of the anion exchange membrane. Furthermore, when using a metal core, for example, a stainless steel (alloy) core may be used.

[0041] Although the surface of the core material is not particularly specified, when a hygroscopic material is used, it is desirable to coat the surface of the anion exchange membrane roll with a material having water vapor barrier properties. By coating with a material having water vapor barrier properties, even when a hygroscopic material is used for the core material, for example, it is possible to prevent moisture transfer caused by direct contact of the paper core material with the anion exchange membrane, thereby suppressing the impact on the state of the ion exchange membrane roll. From this perspective, it is also recommended to use a plastic core material. When a core material is used, it is preferable to cover the anion exchange membrane roll with an outer packaging material so as to enclose the core material as well.

[0042] [Interior Material] The anion exchange membrane roll product according to one embodiment of the present invention may further include an interior material. The interior material covers the anion exchange membrane roll and is located more inward than the exterior material. The interior material can further suppress humidity changes in the vicinity of the anion exchange membrane roll. Preferred materials for the interior material include the same materials as those for the exterior material described above, and for example, a film formed of at least one selected from the group consisting of polyethylene film, polypropylene film, and polyethylene terephthalate film is preferred.

[0043] As with exterior materials, from the viewpoint of water vapor barrier properties, the water vapor permeability of interior materials is 0 to 100 g / (m２ ·day) is preferred, and 0 to 90 g / (m ２ ·day) is more preferable, and 1 to 90 g / (m ２ ・day) is more preferable.

[0044] From the viewpoint of maintaining the shape of the roll, the tensile modulus of elasticity of the interior material is preferably 10 MPa or more and 6000 MPa or less, more preferably 500 MPa or more and 5500 MPa or less, and even more preferably 1000 MPa or more and 5000 MPa or less.

[0045] From the viewpoint of maintaining the shape of the roll, the thickness of the interior material is preferably 10 to 500 μm, and more preferably 20 to 250 μm.

[0046] [Humidity Regulator] In an anion exchange membrane roll product according to one embodiment of the present invention, the anion exchange membrane roll is covered with a water vapor barrier exterior material, but a humidity regulator can also be placed inside the exterior material. Examples of humidity regulators include type B silica gel, clay, and diatomaceous earth. An appropriate amount of desiccant such as type A silica gel or quicklime (calcium oxide) may also be added (for example, to the extent that the internal environmental humidity does not fall below 10% RH).

[0047] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0048] Example 1 Production Example 1-1 Preparation of Polymerizable Composition Chloromethylstyrene (95 parts by mass), a styrene solution of 57% by mass of divinylbenzene (5 parts by mass), a polymerization initiator (trade name: Perbutyl (registered trademark), 0.5 parts by mass), and an epoxy compound (trade name: Epolite 40E (registered trademark), 5 parts by mass) were mixed to obtain a polymerizable composition.

[0049] <Production Example 1-2: Production of wet anion exchange membrane roll> As a substrate for the anion exchange membrane, a polyethylene porous membrane roll having a porosity of 44%, a thickness of 25 μm, a width of 10,000 mm and a length of 400 m was used.

[0050] The substrate was unwound and immersed in a tank containing the polymerizable composition to support the polymerizable composition, and then a 50 μm thick polyethylene terephthalate film (PET film) was placed on one side and taken up on a hard chrome-plated metal roll to obtain a polyethylene porous film roll with a laminated film, which included the polymerizable composition with the PET film and the substrate.

[0051] The obtained polyethylene porous membrane roll with the laminated film was heated at 80°C for 5 hours under nitrogen pressure of 0.3 MPa to polymerize the polymerizable composition in the porous membrane, thereby obtaining an anion exchange membrane roll with the laminated film.

[0052] The laminated film was unwound from the resulting anion exchange membrane roll with the laminated film, the PET film was peeled off, and the roll was rewound to produce an anion exchange membrane roll without the PET film. This anion exchange membrane roll was immersed in an aqueous solution containing 6% by mass of trimethylamine and 25% by mass of acetone at room temperature for 16 hours to amminate the chloromethylstyrene polymerized portion, and then immersed in a 0.5 mol / L aqueous potassium bicarbonate solution to ion-exchange 95% of the counterions of the quaternary ammonium base in the membrane from chloride ions to bicarbonate ions. The anion exchange membrane roll was then immersed in pure water for washing to obtain a wet anion exchange membrane roll.

[0053] <Production Example 1-3: Production of an anion exchange membrane roll with adjusted moisture content> The wet anion exchange membrane roll produced in Production Example 1-2 was unwound at a speed of 1 m / min, and 30 ° C. hot air was blown onto the front and back of the film for 2 minutes to dry it to a certain extent, and then wound up to obtain an anion exchange membrane roll. Thereafter, in a room adjusted to room temperature of 20 ° C. and humidity of 60%, the film was slit at a speed of 10 m / min using a slitting machine and wound around a plastic (ABS) core material with an inner diameter of 6 inches, to obtain an anion exchange membrane roll with a width of 500 mm, a length of 400 m, a thickness of 27 μm, and a bicarbonate counterion. In this way, an anion exchange membrane roll with a moisture content MC of 15.0 mass% was obtained. The saturated moisture content SC of this anion exchange membrane was 54.9 mass%, and the wetness ratio (MC / SC) was 27.3%.

[0054] <Anion exchange membrane roll packaging and environmental testing> Next, in the same room where the slitting was performed, the anion exchange membrane roll was covered with a 25 μm thick polyethylene film packaging material, and the periphery was heat-sealed to prevent air from entering. After storing in a warehouse for 90 days, it was opened and left to stand in a room with a temperature of 20°C and a humidity of 70%, and after 2 hours, the winding state of the anion exchange membrane roll and the quality of the anion exchange membrane of the layer closest to the outermost layer were confirmed. Note that the maximum relative humidity over the 90 days was 95%, the minimum was 13%, and the temperature was a minimum of 3.8°C and a maximum of 37.3°C. Visual observation showed that the winding state of the anion exchange membrane roll and the quality of the membrane were both good.

[0055] (Example 2) Except for using an anion exchange membrane with a water content of 7.5 wt %, the same experiment and observation were carried out as in Example 1. As a result of visual observation, the state of winding of the anion exchange membrane roll and the quality of the membrane were both good.

[0056] Here, the water content of the anion exchange membrane was appropriately adjusted by changing the hot air temperature and drying time when drying the anion exchange membrane, or by changing the temperature and humidity environment of the room in which the anion exchange membrane was slit. Similar explanations will be omitted below.

[0057] (Example 3) Except for using an anion exchange membrane with a water content of 20.0 wt %, the same experiment and observation were carried out as in Example 1. As a result of visual observation, the state of winding of the anion exchange membrane roll and the quality of the membrane were both good.

[0058] (Example 4) The same experiment and observation were carried out as in Example 3, except that the outer packaging material was changed from a 25 μm thick polyethylene film to a 30 μm thick polyethylene terephthalate film. Visual observation revealed that the winding state of the anion exchange membrane roll and the quality of the membrane were both good.

[0059] (Example 5) The same experiments and observations as in Example 1 were carried out, except that an anion exchange membrane with a moisture content of 11.0 wt % was used, the exterior material was changed from a 25 μm thick polyethylene film to a 25 μm thick polypropylene film, and the core material was changed from a plastic (ABS) to a paper material (with a waterproof surface coating). Visual observation revealed that there were no problems with the winding state of the anion exchange membrane roll and the quality of the membrane.

[0060] (Example 6) The same experiment and observation as in Example 5 were carried out, except that the core material was changed from paper (with a surface waterproof coating) to paper (without a surface waterproof coating). Visual observation revealed slight wrinkles in the core material, but the state of winding of the anion exchange membrane roll and the quality of the membrane were both in good condition.

[0061] (Example 7) Experiments and observations were performed in the same manner as in Example 1, except that an anion exchange membrane with a water content of 9.0 wt% was used, the exterior material was changed from a 25 μm-thick polyethylene film to a stainless steel can (with a thick bottom of 0.7 mm), and the core material was changed from plastic (ABS) to stainless steel. Visual observations showed that the winding condition of the anion exchange membrane roll and the quality of the membrane were both good. In the case of the stainless steel can, the anion exchange membrane roll was lightly wrapped in polyethylene film (unsealed) and placed in an open-topped stainless steel can, which was then sealed with a stainless steel lid (mechanical fitting).

[0062] (Example 8) Experiments and observations were carried out in the same manner as in Example 6, except that the anion exchange membrane roll was covered with a polyolefin-based interior material at a position on the inner circumferential side of the exterior material. The thickness of the interior material was 50 μm, and the water vapor permeability was 5.0 g / (m ２ ·day) and the tensile modulus was 1800 MPa. Visual observation revealed that there were no problems with the winding state of the anion exchange membrane roll and the quality of the membrane.

[0063] Comparative Example 1: Except for using an anion exchange membrane with a moisture content of 3.0 wt %, the same experiment and observation were carried out as in Example 1. As a result of visual observation, it was confirmed that the anion exchange membrane roll was loose and that its end faces were misaligned (uneven).

[0064] Comparative Example 2: Except for using an anion exchange membrane with a water content of 32.0 wt %, the same experiment and observation were carried out as in Example 1. Visual observation confirmed that condensation occurred partially, followed by tightness of the anion exchange membrane roll.

[0065] Comparative Example 3: An anion exchange membrane with a water content of 13.0 wt % was used, the exterior material was changed from a 25 μm thick polyethylene film to a 15 μm thick nylon film, and the core material was changed from a plastic (ABS) to a paper material (with a waterproof surface coating). Visual observation confirmed that the anion exchange membrane was deformed and wrinkled.

[0066] (Comparative Example 4) An anion exchange membrane with a moisture content of 15.0 wt % was used, and the outer packaging material was changed from a polyethylene film 25 μm thick to a paper material (basis weight 50 g / m ２ The same experiments and observations as in Example 1 were carried out, except that the anion exchange membrane roll was replaced with the paper roll described above. Visual observation confirmed that the anion exchange membrane roll was tightly wound and partially bent. The packaging method was to seal the roll by gluing the papers together with an adhesive.

[0067] (Comparative Example 5) The exterior material was made of paper (basis weight 50 g / m ２ The same experiment and observation were carried out as in Comparative Example 4, except that the anion exchange membrane roll was replaced with a 25 μm thick polyethylene film and the papers were not sealed by being glued together. Visual observation confirmed that the anion exchange membrane roll was tightened and the membranes were adhered to each other.

[0068] (Comparative Example 6) Experiments and observations were performed in the same manner as in Comparative Example 3, except that an anion exchange membrane with a moisture content of 8.0 wt % was used, no exterior material was used, and the core material was changed from plastic (ABS) to paper (with a waterproof surface coating). Visual observation confirmed that the anion exchange membrane roll was loose and that its end faces were misaligned (uneven).

[0069] The exterior materials and core materials are summarized in Tables 1 and 2. The results of each Example and Comparative Example are summarized in Table 3. In Table 3, in the winding condition and film quality evaluation, "◎" indicates good, "◯" indicates that slight loosening of the winding or wrinkles occurred but were not a problem, and "×" indicates that defects such as loosening of the winding occurred.

[0070]

[0071]

[0072]

Claims

1. An anion exchange membrane roll product, comprising: a roll of an anion exchange membrane containing water; and an exterior material covering the roll of the anion exchange membrane, wherein the anion exchange membrane has a water content MC of 10% or more and a saturated water content SC of the anion exchange membrane at 20°C, both inclusive, and the exterior material has a water vapor permeability of 100 g / (m ２ 10 days) or less, and the anion exchange membrane roll is sealed on the inner circumferential side of the exterior packaging material.

2. The anion exchange membrane roll product according to claim 1, wherein the moisture content MC of the anion exchange membrane is 5% by mass or more and 25% by mass or less.

3. The anion exchange membrane roll product according to claim 1 or 2, wherein the saturated water content SC of the anion exchange membrane is 25% by mass or more and 100% by mass or less.

4. The anion exchange membrane roll product according to claim 1 or 2, wherein the exterior material is formed of at least one material selected from the group consisting of polyethylene film, polypropylene film, and polyethylene terephthalate film.

5. The anion exchange membrane roll product according to claim 1 or 2, further comprising a core material that serves as a central axis of the anion exchange membrane roll, the core material being made of plastic.

6. The anion exchange membrane roll product according to claim 1 or 2, wherein 90% or more of the counter ions of the anion exchange membrane are bicarbonate ions.

7. The anion exchange membrane roll product according to claim 1 or 2, wherein the tensile modulus of the exterior material is 1 MPa or more and 3000 MPa or less.

8. The anion exchange membrane roll product according to claim 1 or 2, further comprising an interior material, the interior material covering the anion exchange membrane roll and being located more inward than the exterior material.

9. The anion exchange membrane roll product according to claim 8, wherein the interior material is formed of at least one film selected from the group consisting of a polyethylene film, a polypropylene film, and a polyethylene terephthalate film.

10. The anion exchange membrane roll product according to claim 8, wherein the tensile modulus of the interior material is 10 MPa or more and 6000 MPa or less.

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