Sheet, sealing material, fuel cell, electrolytic cell, method for producing sheet, and method for producing sealing material

Abstract

Provided are a sheet and a sealing material which are based on clay and have excellent water resistance in high-temperature environments. The sheet comprises an expanded clay and a non-expanded clay. The expansive clay contains a first component and a second component having a structure different from that of the first component. The non-swellable clay is a clay in which ions of a first component and ions of a second component are exchanged in a dispersion medium, and exhibits non-swellable properties when heated. The sheet contains a first component, a second component, and optionally a third component, the first component being an expanded clay in which the interlayer is replaced with Li, the second component being Na-type montmorillonite or K-type montmorillonite, and the third component being a filler. When the total weight of the first component, the second component, and the third component is taken as 100% by weight, the content of the first component is 25% by weight to 80% by weight, the content of the second component is 10% by weight to 50% by weight, and the content of the third component is 0% by weight to 80% by weight.

Description

Technical Field

[0001] The present invention relates to a sheet, a sealing material, a fuel cell, an electrolytic cell, a method for producing the sheet, and a method for producing the sealing material. Background Art

[0002] Sealing materials such as gaskets and packings are used in various industrial devices and piping flanges. As gaskets, sheet gaskets, spiral-wound gaskets, serrated gaskets, and the like are known.

[0003] In particular, sheets containing clay as a main component are used for gaskets for high temperature applications. Clay sheets are classified into those using non-expanding clay and those using expanding clay.

[0004] For example, Patent Document 1 describes a sealing material comprising talc as a non-swelling clay, mixed with inorganic fibers and a binder. Furthermore, Patent Document 2 describes a sheet comprising modified vermiculite as a swelling clay, and a sealing material using the sheet. Patent Document 3 describes a sheet comprising montmorillonite, a type of smectite, as a swelling clay, and a sealing material using the sheet. Patent Document 4 describes a sealing material in which the interlayer Na contained in montmorillonite is exchanged for Li and then heated.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2017 / 115399

[0008] Patent Document 2: Japanese Patent No. 6999649

[0009] Patent Document 3: Japanese Patent No. 3855003

[0010] Patent Document 4: Japanese Patent No. 4973856

[0011] Patent Document 5: Japanese Patent Application Laid-Open No. 2022-109896 Summary of the Invention

[0012] Problems to be solved by the invention

[0013] Typically, fuel cells and electrolytic cells are maintained at a temperature of 300°C or higher after stacking and assembly to remove organic matter from the raw materials (remove the binder) (e.g., Patent Document 5). Furthermore, fuel cells and electrolytic cells allow aqueous fluids containing water vapor to pass through them, so gaskets used in fuel cells and electrolytic cells preferably exhibit water resistance during heat treatment at approximately 300°C.

[0014] Sealing materials used in high-temperature environments are required to have high water resistance and steam resistance. However, when conventional clay sheets using expanded clay are used as sealing materials, there is a possibility that the water resistance after heating at 300°C may not be maintained.

[0015] Furthermore, the sealing material comprising non-expandable clay, fibers, and an adhesive disclosed in Patent Document 1 suffers from insufficient sealing performance due to the presence of fibers. Furthermore, when using organic adhesives or organic fibers, the organic components burn away in high-temperature environments, creating voids and deteriorating sealing performance. Silicone is also used as an inorganic adhesive, but it produces siloxane-based outgassing in high-temperature environments, making it unsuitable for use near electronic components or electrodes.

[0016] The modified vermiculite described in Patent Document 2 can be formed into sheets without the use of fibers or binders, and exhibits sealing properties in high-temperature environments. However, its high iron content limits its use near electronic components and electrodes, where insulation is required.

[0017] The smectite disclosed in Patent Document 3 can be formed into sheets without the use of fibers or binders. However, it warps and shrinks significantly in high-temperature environments, presenting problems with dimensional stability. Furthermore, during production, it gels at relatively low concentrations, making it prone to warping during drying and problematic for thick film formation.

[0018] Patent Document 4 describes a sheet that imparts water resistance by exchanging interlayer Na in montmorillonite for Li and then heating it, causing the interlayer Li to migrate to the octahedral layers. However, the sheet's heat resistance is insufficient in high-temperature environments, leading to warping and problems with thick film formability.

[0019] An object of the present invention is to provide a sheet based on expanded clay, having excellent water resistance in a high-temperature environment and improved manufacturability, a sealant, a fuel cell and an electrolytic cell using the sealant, a method for producing the sheet, and a method for producing the sealant.

[0020] Means for solving problems

[0021] The present inventors have conducted intensive studies and have found that a sheet having excellent water resistance in a high-temperature environment can be obtained by drying a slurry prepared by adding a solvent such as water to expanded clay and smectite in which interlayers are substituted with Li.

[0022] The present invention relates to the following sheets, sealing materials, fuel cells and electrolytic cells using the sealing materials, methods for producing the sheets, and methods for producing the sealing materials. [1]

[0024] A sheet, characterized in that

[0025] Contains expanded clay and non-expanded clay,

[0026] The expanded clay comprises a first component and a second component having a structure different from that of the first component.

[0027] The non-swelling clay is clay in which ions of the first component and the second component are exchanged in a dispersion medium, and exhibits non-swelling properties when heated. [2]

[0029] The sheet according to [1], comprising the first component, the second component, and optionally a third component,

[0030] The first component is expanded clay whose interlayers are replaced by Li.

[0031] The second component is Na-type montmorillonite or K-type montmorillonite,

[0032] The third component is a filler.

[0033] When the total weight of the first component, the second component, and the third component is set to 100 weight%, the content of the first component is greater than 25 weight% and less than 80 weight%, the content of the second component is greater than 10 weight% and less than 50 weight%, and the content of the third component is greater than 0 weight% and less than 80 weight%. [3]

[0035] The sheet according to [1] or [2], wherein the water absorption rate in a 24-hour pure water immersion test after heating at 300°C for 24 hours is 50% or less. [4]

[0037] The sheet according to [1] or [2], wherein the water absorption in a 24-hour pure water immersion test after heating at 300°C for 24 hours is 50% or less, and the water absorption in a 24-hour pure water immersion test after heating at 600°C for 24 hours is 25% or less. [5]

[0039] The sheet according to [1] or [2], wherein the water absorption in a 24-hour pure water immersion test after heating at 300°C for 24 hours is 50% or less, and the water absorption in a 24-hour pure water immersion test after heating at 700°C for 24 hours is 20% or less. [6]

[0041] The sheet according to [1] or [2], wherein the iron oxide content is 6 wt% or less when the weight of the entire sheet is taken as 100 wt%. [7]

[0043] The sheet according to [1] or [2], wherein the first component is expanded muscovite,

[0044] In the expanded muscovite, K between the layers of muscovite + At least a portion of the ions are Li + Ion exchange. [8]

[0046] The sheet according to [1] or [2], wherein the filler contains talc, muscovite, sericite, kaolinite, or fused silica. [9]

[0048] A sealing material comprising the sheet described in [1] or [2].

[10]

[0050] The sealing material according to [9] is used for a fuel cell or an electrolytic cell.

[11]

[0052] A fuel cell or electrolytic cell comprising the sealing material described in

[10] .

[12]

[0054] A method for producing a sheet, which is the method for producing a sheet according to [2], wherein:

[0055] The method for manufacturing the sheet comprises:

[0056] a step of mixing the first component, the second component, and the third component to form a mixture; and

[0057] A step of exchanging ions between the first component and the second component, and then forming the mixture into a sheet and heating it.

[13]

[0059] A method for manufacturing a sealing material, comprising the step of assembling a sheet manufactured by the sheet manufacturing method described in

[12] as a part of a gasket or a liner.

[0060] Effects of the Invention

[0061] The sheet of the present invention comprises swelling clay and non-swelling clay. The swelling clay comprises swelling clay in which the interlayers are replaced with Li, Na-type montmorillonite or K-type montmorillonite, which is a smectite, as the swelling clay, and clay in which the ions of the first component and the second component are exchanged in a dispersion medium and which exhibits non-swelling properties upon heating as the non-swelling clay. This results in a sheet with low water absorption and high water resistance. Furthermore, even when formed into a thick film, the sheet does not warp, resulting in high manufacturability. Furthermore, since the smectite acts as a binding material, it has high handling strength.

[0062] Therefore, it is possible to achieve high heat resistance, high water resistance, high manufacturability, high sealing performance, and reduction in outgassing, which have not been achieved in the conventional technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1A This is a table showing the types and amounts of components blended in Experimental Examples 1 to 10.

[0064] Figure 1B This is a table showing the types and amounts of components blended in Experimental Examples 10-1 to 10-4.

[0065] Figure 2 This is a table showing the types and amounts of components mixed in Experimental Examples 11 to 20.

[0066] Figure 3A This is a table showing the types and amounts of components used in sheet formation in Experimental Examples 1 to 10.

[0067] Figure 3B This is a table showing the types and amounts of components used in sheet formation in Experimental Examples 10-1 to 10-4.

[0068] Figure 4 This is a table showing the types and amounts of components used in sheet formation in Experimental Examples 11 to 20.

[0069] Figure 5A This is a table showing the results of sheet evaluation in Experimental Examples 1 to 10.

[0070] Figure 5B This is a table showing the results of sheet evaluation in Experimental Examples 10-1 to 10-4.

[0071] Figure 6 This is a table showing the results of sheet evaluation in Experimental Examples 11 to 20. DETAILED DESCRIPTION

[0072] Hereinafter, an embodiment of the present invention (hereinafter, this embodiment) will be described with reference to the drawings. This embodiment relates to a sheet, a sealing material, a fuel cell, an electrolytic cell, a method for manufacturing a sheet, and a method for manufacturing a sealing material.

[0073] <Definition>

[0074] In the present specification, ○ to △ (for example, ○ weight % to △ weight %) means ○ or more and △ or less (○ weight % or more and △ weight % or less).

[0075] In the present specification, the terms “comprising” or “including” mean that the specified components are included, but do not exclude the presence of other components.

[0076] <film>

[0077] The sheet of this embodiment can be used, for example, as a sealant. The sheet of this embodiment comprises swelling clay and non-swelling clay. The swelling clay comprises a first component and a second component having a different structure from the first component. Furthermore, the non-swelling clay is clay in which the ions of the first and second components are exchanged in a dispersion medium, and exhibits non-swelling properties upon heating.

[0078] For example, the first component is expanded clay such as expanded muscovite (Li-type muscovite) and expanded vermiculite (Li-type vermiculite) in which interlayers are replaced with Li, and the second component is expanded smectite such as Na-type montmorillonite and K-type montmorillonite.

[0079] <Expanded Clay>

[0080] In the present invention, the flakes contain expanded clay as a blending component. The flakes are composed of expanded clay layers (hereinafter referred to as Li-type clay layers) such as Li-type muscovite and Li-type vermiculite, in which the interlayers are replaced with Li, and expanded clay layers such as Na-type montmorillonite and K-type montmorillonite, also known as smectite.

[0081] The Li-type clay layer and smectite as raw materials of the present invention are both swelling clays and have no water resistance when they are simple substances. + Ionic expanded clay and smectite mixed, Li + Ions move to the interlayers of smectite, and the Li + The ions are heated and thus move from the interlayer to the octahedral layer. + Ions move between the layers, resulting in water resistance.

[0082] For example, if Li-type muscovite as a Li-type clay layer and Na-type montmorillonite as a smectite are mixed in the state of aqueous dispersion, the interlayer Li + Ions are supplied from Li-type muscovite to Na-type montmorillonite, thereby obtaining Li-type montmorillonite. + The ions move to the interlayer of Li-type muscovite, thus obtaining Na-type muscovite. Then, water is removed from the obtained mixed solution and heated, and the Li-type montmorillonite Li + The ions migrate to the octahedral layer, thereby imparting water resistance.

[0083] The interlayer ions of smectite are preferably non-Li + ions. If it is not Li + ions, the Li-type clay layer can also be resistant to hydration by utilizing the ions introduced from smectite into the Li-type clay layer. The interlayer ions are particularly preferably K + ions, Na +ions, Ca 2+ ions, Mg 2+ ions. The reason is that K + ions, Na + ions, Ca 2+ ions, Mg 2+ Ions are cheap and highly soluble in water, and can be easily exchanged. Among them, Na is particularly preferred. + ions, Ca 2+ ions. The reason is that Na + ions, Ca 2+ Ions are present in natural smectite, so prior ion exchange treatment can be omitted.

[0084] <Non-expanding clay>

[0085] In the present invention, non-swelling clay is included as a component of the sheet. Non-swelling clay is obtained by ion exchange between a Li-type clay layer and smectite in a dispersion medium, and exhibits non-swelling properties upon heating. Table 1 shows whether the clay layer becomes expandable or non-swelling upon heat treatment. In Table 1, expandable clay layers are marked with "0" and non-swelling clay layers are marked with "x."

[0086] [Table 1]

[0087]

[0088] As shown in Table 1, when muscovite or vermiculite is heat treated at 300℃, the interlayer Li + In the case of ions, it shows expansion, and the interlayer contains Na + ions, K + ions, Mg 2+ ions, Ca 2+ In the case of ions, the interlayer ions are fixed and thus exhibit non-expanding properties.

[0089] In addition, when montmorillonite or saponite as smectite is heat-treated at 300°C, in addition to the Li + Ionic montmorillonite shows expansion properties, and the interlayer contains Li + Ionic montmorillonite exhibits non-swelling properties due to the movement of interlayer ions into the layers.

[0090] Therefore, the sheet of the present invention is formed by mixing Li-type muscovite or Li-type vermiculite (first component) as swelling clay with swelling smectite (second component), performing interlayer ion exchange, and heating to form a sheet containing swelling clay and non-swelling clay.

[0091] (1st ingredient)

[0092] The first component preferably has Li + The clay layer in the sheet of the present invention is not limited in type as long as it contains Li as interlayer ions. + Examples of ionic expanded clay materials include Li-type muscovite, Li-type vermiculite, and Li-type phlogopite. However, in applications as gaskets for industrial equipment, Li-type muscovite is preferably used because it contains less iron and impurities.

[0093] The first component is, for example, expanded clay in which the interlayers are replaced with Li, preferably expanded muscovite. Here, "muscovite" is a concept including "sericite" which is another name when it is fine particles. In addition, expanded muscovite includes "expanded sericite" when it is fine particles. Expanded muscovite refers to K in the interlayers of muscovite. + At least a portion of the ions are selected from Li + ions, Ca 2+ ions, Mg 2+ A material that exchanges at least one ion (ion that imparts expansion) from a group of ions. Expanded sericite refers to K between the layers of sericite. + At least a portion of the ions are selected from Li + ions, Ca 2+ ions, Mg 2+ A material in which at least one ion (ion imparting swelling property) from a group of ions is exchanged. Note that the swelling clay in which interlayers are replaced with Li is not limited to swelling muscovite, but may also be modified vermiculite (swelling vermiculite).

[0094] Muscovite is a type of silicate mineral (phyllosilicate mineral) with the chemical formula K2Al4(Si6·Al2)O 20 (OH)4 represents a triple structure containing Al and K between layers of silicate tetrahedrons. Sericite is fine particles of muscovite, a layered silicate mineral. The muscovite used in this embodiment is preferably a fluorine-mica-type muscovite that does not contain fluorine, from the perspective of preventing the generation of fluorine-containing gases.

[0095] For the expanded clay in which the interlayers are replaced with Li as the first component, the K + At least a portion of the ions are modified with Li +The modification of muscovite is not particularly limited; for example, muscovite or sericite can be mixed with heated and molten lithium nitrate and allowed to react for a predetermined time. The expanded muscovite can be dispersed in water, for example, by removing the lithium nitrate by filtration and washing, followed by adding pure water and stirring.

[0096] Li contained between the layers of expanded muscovite + Ions and K + The ratio of ions is Li + :K + =20at%:80at%~70at%:30at%, preferably Li + :K + =30at%:70at%~60at%:40at%, more preferably Li + :K + =40at%:60at% to 60at%:40at%, more preferably Li + :K + =40at%:60at%~55at%:45at%. The exchanged ions are not K + But Ca 2+ Mg 2+ The same ratio applies to the case of .

[0097] (2nd ingredient)

[0098] The second component is smectite, preferably montmorillonite, saponite, hectorite or beidellite. Smectite is a 2:1 type mineral having a structure with Al octahedral layers between layers of silicate tetrahedrons. In smectite, Al is replaced by Mg in the Al octahedral layers. 2+ ions, Fe 2+ ions, Fe 3+ The cations are replaced by ions, resulting in a negative charge. As a result, the distance between the lattice layers is far, and the cations are weakly retained, making it easy for water to enter the interlayers and the lattice to expand.

[0099] As the type of smectite, montmorillonite and saponite are preferred, montmorillonite is more preferred, and Na-type montmorillonite or K-type montmorillonite is particularly preferred. The octahedral layer of montmorillonite is composed of Al and Mg, and there are many crystal defects. + Ions can easily migrate to the octahedral layers. In addition, montmorillonite is naturally present and therefore available at low cost.

[0100] The added weight ratio of smectite to the weight of the sheet is preferably 5 to 55 wt%, more preferably 10 to 50 wt%, and particularly preferably 20 wt%. The closer the added amount is to 20 wt%, the more effective the water resistance effect when heated at 300°C.

[0101] In addition, the more smectite is added, the stronger the sheet will be. On the other hand, if too much smectite is added, the heat resistance will deteriorate. In addition, the appearance of the sheet will be wrinkled and warped.

[0102] (3rd ingredient)

[0103] The third component is a filler, preferably a filler of clay or oxide. The third component is optionally contained in a sheet. Here, the filler of clay or oxide refers to at least one or more of the group consisting of muscovite, sericite, talc, kaolinite, and fused silica. It should be noted that, as these fillers, fired materials can also be used. By including non-expandable fillers such as muscovite, the proportion of smectite required for water resistance can be reduced.

[0104] The sheet of the present invention preferably contains a filler as a third component in addition to the Li-type clay layer as the first component and the smectite as the second component. Fillers such as talc, for example, do not expand, and thus can improve water resistance even if the weight ratio of smectite to the overall sheet is small. Furthermore, the use of a highly heat-resistant filler can improve the heat resistance of the sheet.

[0105] The weight ratio of the filler is preferably 0 to 80 wt %. More preferably, it is 50 wt %. When the weight ratio of smectite in the sheet is the same, the more filler, the better the water resistance. On the other hand, if the filler is too much, the handling strength is reduced.

[0106] (Total ratio of the first ingredient, the second ingredient, and the third ingredient in the tablet)

[0107] When the weight of the entire sheet is set to 100 weight%, the total of the first component, the second component, and the third component is 90 weight% or more, preferably 92 weight% or more, more preferably 93 weight% or more, further preferably 95 weight% or more, further more preferably 96 weight% or more, and particularly preferably 97 weight% or more.

[0108] (Ratio of the first component, the second component, and the third component during mixing)

[0109] When the total weight of the first component, the second component, and the third component is taken as 100% by weight, the first component is preferably 25% by weight or more and 80% by weight or less. The first component is preferably present in an amount of at least 25% by weight, preferably 30% by weight or more, more preferably 50% by weight or more, further preferably 60% by weight or more, particularly preferably 75% by weight or more, and particularly more preferably 80% by weight or more. Furthermore, the first component may be present in an amount of at most 100% by weight or less, 90% by weight or less, 80% by weight or less, 70% by weight or less, 65% by weight or less, or 50% by weight or less.

[0110] When the total weight of the first component, the second component, and the third component is 100 weight%, the first component is contained in an amount of 25-100 weight%, 30-100 weight%, 40-100 weight%, 50-100 weight%, 60-100 weight%, 65-100 weight%, 70-100 weight%, 75-100 weight%, 80-100 weight%, 25-95 weight%, 25-90 weight%, 25-80 weight%, 25-75 weight%, 25-70 weight%, 25-65 weight%, 25-60 weight%, and 25-50 weight%.

[0111] When the total weight of the first component, the second component, and the third component is taken as 100% by weight, the second component is preferably 10% by weight or more and 50% by weight or less. The second component is preferably contained in an amount of at least 5% by weight, preferably 7% by weight or more, and more preferably 10% by weight or more. Alternatively, the second component may be contained in an amount of at most 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, or 5% by weight or less.

[0112] When the total weight of the first component, the second component, and the third component is set to 100 weight%, the second component is contained in an amount of 25-100 weight%, 30-100 weight%, 40-100 weight%, 50-100 weight%, 60-100 weight%, 65-100 weight%, 70-100 weight%, 75-100 weight%, 80-100 weight%, 25-95 weight%, 25-90 weight%, 25-80 weight%, 25-75 weight%, 25-70 weight%, 25-65 weight%, 25-60 weight%, and 25-50 weight%.

[0113] When the total weight of the first, second, and third components is set to 100% by weight, the third component is preferably 0% by weight or more and 80% by weight or less. The third component is preferably at least 10% by weight, preferably at least 20% by weight, more preferably at least 25% by weight, further preferably at least 30% by weight, particularly preferably at least 40% by weight, and particularly more preferably at least 50% by weight. Alternatively, the third component may be at most 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, or 50% by weight or less. By varying the proportion of the third component, any desired state of resilience can be achieved. However, if the proportion is excessively increased, mechanical strength decreases.

[0114] When the total weight of the first component, the second component, and the third component is set to 100 weight%, the third component is contained in an amount of 0 to 80 weight%, 0 to 75 weight%, 0 to 70 weight%, 0 to 60 weight%, 0 to 50 weight%, 0 to 40 weight%, 0 to 35 weight%, 0 to 30 weight%, 0 to 25 weight%, 0 to 20 weight%, 5 to 80 weight%, 10 to 80 weight%, 20 to 80 weight%, 25 to 80 weight%, 30 to 80 weight%, 35 to 80 weight%, 40 to 80 weight%, and 50 to 80 weight%.

[0115] Taking the weight before heating as 100 weight %, the weight loss rate of the third component when heated to 1000° C. is 15 weight % or less, preferably 13 weight % or less, more preferably 10 weight % or less, further preferably 8 weight % or less, further preferably 7 weight % or less, and particularly preferably 6 weight % or less.

[0116] The content of the iron component of the third component is small. Specifically, the content of the iron component converted into iron oxide (Fe2O3) contained in the third component is 3 weight % or less, preferably 2 weight % or less, more preferably 1.5 weight % or less, further preferably 1.0 weight % or less, further more preferably 0.8 weight % or less, and particularly preferably 0.5 weight % or less. Here, the content of each component can be measured by fluorescent X-ray analysis (XRF) when expressed in terms of oxide conversion. It should be noted that, even if the content of each component is expressed in terms of oxide conversion, each component does not necessarily need to be contained in the form of oxide.

[0117] (Content ratio of the first component to the second component)

[0118] The ratio of the content of the first component to the content of the second component (ratio by weight) is 10:90-100:0, 15:85-100:0, 20:80-100:0, 25:75-100:0, 30:70-100:0, 40:60-100:0, 50:50-100:0, 60:40-100:0, 65:35-100:0 0, 70:30~100:0, 75:25~100:0, 80:20~100:0, 25:75~95:5, 25:75~90:10, 25:75~80:20, 25:75~75:25, 25:75~70:30, 25:75~65:35, 25:75~60:40, 25:75~50:50.

[0119] (Ratio of expanded clay to non-expanded clay in tablets)

[0120] When a sheet containing swelling clay and non-swelling clay is formed by mixing swelling clay and heating to effect interlayer ion exchange, the preferred ratios of the components are as follows, with the total weight of the swelling clay as the first component, the swelling clay as the second component, the non-swelling clay (clay that exhibits non-swelling properties upon heating), and the filler being taken as 100% by weight.

[0121] The swelling clay as the first component is preferably from 5% by weight to 90% by weight, and more preferably from 10% by weight to 70% by weight.

[0122] The swelling clay as the second component is preferably in a range of 2% by weight to 50% by weight, and more preferably in a range of 5% by weight to 40% by weight.

[0123] The content of the non-swelling clay (clay that exhibits non-swelling properties by heating) is preferably 5% by weight or more and 30% by weight or less, and more preferably 10% by weight or more and 25% by weight or less.

[0124] <Method for producing sheet>

[0125] The method for producing a sheet of this embodiment includes the steps of mixing a first component, a second component, and an optional third component to form a mixture, and further includes the steps of ion-exchanging the first component with the second component, molding the mixture into a sheet, and heating it.

[0126] By including Li + Ionic expanded clay is mixed with expanded clay smectite to make Li + Ions move to the interlayer of smectite, and the Li + ions, causing them to move from the interlayer to the octahedral layer.

[0127] A solvent such as water is added to the mixture to adjust the viscosity of the slurry to the appropriate viscosity for the molding method. The mixture is then molded using extrusion molding, calendar rolls, a film applicator, a doctor blade, a bar coater, screen printing, etc., and dried to obtain a sheet.

[0128] <Sealing material>

[0129] The sheet of the present embodiment can be used as a sealing material for various piping such as fuel cells such as various industries, solid oxide fuel cells (SOFC), electrolytic cells such as solid oxide electrolytic cells (SOEC), and exhaust pipes of automobiles, such as gaskets and liners. The sheet of the present embodiment can be used as a sealing material itself, or as a part of a sealing material such as a gasket or a liners. As the shape of the product of the sealing material, a sheet gasket, a spiral gasket, a serrated gasket, etc. can be exemplified, but it is not limited to these.

[0130] (without adhesive)

[0131] The sheet of this embodiment and the sealing material including the sheet are substantially free of adhesive. The adhesive is not particularly limited, and examples thereof include rubber / adhesives. More specifically, examples include acrylonitrile-butadiene rubber, styrene-butadiene rubber, polybutadiene rubber, silicone rubber, acrylic rubber, natural rubber, butyl rubber, chloroprene rubber, ethylene-propylene rubber, fluororubber, polyurethane rubber, acrylic adhesives, and silicone adhesives.

[0132] "Substantially free of a binder" means that, based on the total weight of the sheet being 100% by weight, the amount of binder contained is less than 0.1% by weight (0.1% by weight or less), preferably less than 0.05% by weight (0.05% by weight or less), more preferably less than 0.01% by weight (0.01% by weight or less), further preferably less than 0.001% by weight (0.001% by weight or less), and particularly preferably less than 0.0001% by weight (0.0001% by weight or less). Since the sheet of this embodiment is not mixed with a binder, when used as a sealing material, it has high sealing properties and does not generate outgassing.

[0133] (Iron content)

[0134] The sheet of this embodiment and the sealing material including the sheet preferably have a low iron content. Specifically, when the weight of the entire sheet is set to 100 weight%, the content of iron contained in the sheet of this embodiment and the sealing material including the sheet, as converted to iron oxide (Fe2O3), is 6 weight% or less, preferably 3 weight% or less, more preferably 2 weight% or less, further preferably 1.5 weight% or less, further more preferably 1.0 weight% or less, and particularly preferably 0.8 weight% or less.

[0135] The sheet and sealing material comprising the sheet of this embodiment preferably use muscovite as the Li-type film-forming material. Sheets using muscovite as the Li-type film-forming material have a lower iron content than sheets using vermiculite or phlogopite, resulting in higher insulation properties. Therefore, sheets using muscovite as the Li-type film-forming material are suitable for fuel cell applications such as solid oxide fuel cells (SOFCs) and electrolytic cell applications such as solid oxide electrolytic cells (SOECs), which require high insulation properties.

[0136] (Basis Weight)

[0137] The sheet of the present embodiment and the sealing material including the sheet preferably have a basis weight of 700 to 1300 g / m 2 , more preferably 700 to 1200 g / m 2 , more preferably 750 to 1100 g / m 2 , particularly preferably 800 to 1050 g / m 2 .

[0138] (density)

[0139] The density of the sealing material of this embodiment is preferably 0.5 to 2.5 g / cm at 2 MPa. 3 , more preferably 1.0 to 2.2 g / cm 3 , more preferably 1.2 to 2.0 g / cm 3 In this application, the density can be made to exceed 1.4g / cm 3 The lower the density at 2MPa, the easier it is to follow the unevenness of the target component during compression, and the less leakage from the contact surface.

[0140] The density of the sealing material of this embodiment is preferably 0.5 to 2.8 g / cm at 20 MPa. 3 , more preferably 1.0 to 2.8 g / cm 3 , more preferably 1.2 to 2.8 g / cm 3 In this application, the density can be made to exceed 1.4g / cm 3 The higher the density at 20MPa, the denser the seal is when tightened, and the less physical leakage there is.

[0141] (Compression recovery)

[0142] The compression rate of the sealing material of this embodiment is 15% or more, preferably 20% or more, more preferably 25% or more, further preferably 30% or more, and particularly preferably 40% or more. The higher the compression rate, the easier it is to follow the unevenness of the target component during compression, and the less leakage on the contact surface.

[0143] The sealing material of this embodiment has a recovery rate of 5% or more, preferably 6% or more, more preferably 7% or more, further preferably 8% or more, and particularly preferably 10% or more. The higher the recovery rate, the greater the reaction force during tightening, and the less leakage on the contact surface.

[0144] (Heating dimensional stability)

[0145] The sealing material of this embodiment has high heat resistance. Specifically, the diameter change rate is 10% or less, preferably 8% or less, more preferably 5% or less, further preferably 3% or less, and particularly preferably 1% or less.

[0146] (Volume resistivity)

[0147] The sheet of the present embodiment and the sealing material including the sheet have excellent electrical insulation properties in a high temperature environment. Specifically, the sheet of the present embodiment and the sealing material including the sheet preferably have a volume resistivity value exceeding 2.0×10-1 under the measurement conditions of 600°C and an applied voltage of 100V as insulation performance in a high temperature environment. 6Ω·cm, and the volume resistivity is 3.8×10 6 Ω·cm or more.

[0148] (Fuel cells and electrolyzers)

[0149] The sealing material of this embodiment has the properties described above and can therefore be used for fuel cells. That is, a fuel cell including the sealing material of this embodiment can be provided. A flat-plate SOFC is exemplified as a fuel cell, but the invention is not limited thereto. Furthermore, a solid oxide electrolytic cell (SOEC) can be exemplified as an electrolytic cell, but the invention is not limited thereto.

[0150] <Method for Manufacturing Sealing Material>

[0151] The method for producing a sealing material according to the present embodiment includes a step of assembling the sheet produced by the above-described method for producing a sheet as a gasket and a part of a packing.

[0152] Example

[0153] Hereinafter, the present invention will be described in detail based on specific examples, but the present invention is not limited thereto.

[0154] <1. Production of Expanded Clay and Sheet>

[0155] [1.1 Production of Expanded Muscovite (Modification of Muscovite)]

[0156] Lithium nitrate (8 times the weight of muscovite) was melted at 370°C and mixed with muscovite. Ion exchange was performed by reacting at 370°C for 40 hours. Water was then added and the mixture was filtered. The mixture was washed with pure water and desalinated. Pure water was then added and stirred to obtain a slurry.

[0157] In addition, as expanded vermiculite, a commercial product (MicroLite HTS from Specialty Vermiculite Co., Ltd.) was used.

[0158] [1.2 Sheet Manufacturing]

[0159] After preparing the aqueous dispersion of the Li-type clay layer and the aqueous dispersion of smectite obtained in [1.1] above, the two were mixed, shaped using a doctor blade device, and dried at 100°C for 24 hours to produce a sheet. Note that when a filler is included, the aqueous dispersion of the Li-type clay layer and the aqueous dispersion of smectite were prepared and mixed with the filler, shaped, and dried to produce a sheet.

[0160] In the experimental examples, Li-type muscovite and Li-type vermiculite were used as the expanded clay (the Li-type clay layer of the first component). Na-type montmorillonite, K-type montmorillonite, Li-type montmorillonite, and Na-type saponite were used as the expanded clay (the second component, smectite). Talc, muscovite, kaolin, and platy silica were used as the filler of the third component.

[0161] As Experimental Examples 1 to 20, sheets were prepared with different types and mixing ratios of the first component, the second component, and the third component (filler). The types and amounts of the components in each experimental example were as follows: Figure 1A 、 Figure 1B 、 Figure 2 shown.

[0162] In each experimental example, the types and amounts of components of a sheet containing swellable clay and non-swellable clay were prepared by mixing and heating swellable clay to perform interlayer ion exchange. Figure 3A 、 Figure 3B 、 Figure 4 It should be noted that Figure 3A 、 Figure 3B and Figure 4 The component amounts of the sheets described in the table are calculated values ​​from the component amounts at the time of mixing, and are not actual measured values ​​of the produced sheets.

[0163] <2. Film Evaluation Method>

[0164] The following evaluations were performed on the sheets of the experimental examples.

[0165] (Manufacturability)

[0166] The sheet was punched out to produce a test piece with an outer diameter of 20 mm. This test piece was dried at 100°C for 24 hours to produce a 0.5 mm thick sheet sample. Samples with no warping observed after the test were marked "O"; those with warping observed were marked "X."

[0167] (Water resistance)

[0168] Punch out the sheet to make a test piece with an outer diameter of 20 mm. After heating the test piece at 300°C, 600°C, and 700°C for 24 hours, dry the test piece at 100°C for 15 hours. Then place it in a desiccator to cool naturally, and measure the mass (m1) using a pan balance. After immersing the test piece in pure water for 24 hours, wipe the surface moisture with a rag, and measure the mass (m2) using a pan balance. The value calculated by the following formula (1) is used as the water absorption rate.

[0169] Water absorption (mass %) = ((m2-m1) / m2) × 100 ···Formula (1)

[0170] (Handling)

[0171] The sheet was punched out to produce test pieces with an outer diameter of 20 mm. After heat treatment at 300°C, 600°C, and 700°C for 24 hours, the test pieces were immersed in pure water for 24 hours to prepare sheet samples. When the samples were handled after the test, those that did not disintegrate and could be handled were marked as "0"; those that disintegrated and could not be handled were marked as "X."

[0172] <3. Film Evaluation Results>

[0173] The evaluation results of the sheets of Experimental Examples 1 to 20 are shown in Figure 5A 、 Figure 5B 、 Figure 6 middle.

[0174] (Water resistance)

[0175] The sheets of Experimental Examples 1 to 6, 10-1, and 10-2, which contained Li-type muscovite or Li-type vermiculite as the first component of the swelling clay, Na-type montmorillonite or K-type montmorillonite as the second component of the swelling clay, and contained Na-type muscovite, K-type muscovite, or Na-type vermiculite that exhibits non-swelling properties upon heating, had a water absorption of 50 wt% or less in a 24-hour pure water immersion test after heating at 300°C.

[0176] In particular, in Experimental Examples 1 to 5, 10-1, and 10-2, in the 24-hour pure water immersion test after heating at 300°C, the water absorption rate was less than 40wt%, in the 24-hour pure water immersion test after heating at 600°C, the water absorption rate was less than 25wt%, and in the 24-hour pure water immersion test after heating at 700°C, the water absorption rate was less than 20wt%.

[0177] Comparing Experimental Example 1 and Experimental Example 14, which contain talc as the third component, Experimental Example 1, which contains Na-type montmorillonite as the second component of the expanded clay, has a water absorption rate of 31% in a 24-hour pure water immersion test after heating at 300°C, and a water absorption rate of 18 wt% in a 24-hour pure water immersion test after heating at 600°C and 700°C.

[0178] In contrast, in Experimental Example 14, which did not contain Na-type montmorillonite as the second component of the expanded clay, the sample disintegrated in the 24-hour pure water immersion test after heating at 300°C and 600°C, and had a water absorption rate of 20 wt% or more in the 24-hour pure water immersion test after heating at 700°C.

[0179] In addition, when comparing Experimental Example 5, which does not contain talc as the third component, with Experimental Example 15, the water absorption rate of Experimental Example 5, which uses Na-type montmorillonite as the second component of the expanded clay, was 36% in a 24-hour pure water immersion test after heating at 300°C, and was 12 wt% in a 24-hour pure water immersion test after heating at 600°C.

[0180] In contrast, in Experimental Example 15, which did not contain Na-type montmorillonite as the second component of the swelling clay, the sample collapsed in the 24-hour pure water immersion test after heating at 300° C. and 600° C.

[0181] Therefore, it is understood that a sheet containing a Li-type clay layer as the first component of the swelling clay, smectite as the second component of the swelling clay, and clay that exhibits non-swelling properties upon heating has low water absorption and high water resistance.

[0182] (Handling)

[0183] The sheets of Experimental Examples 1 to 6, 10-1, and 10-2, which contained Li-type muscovite or Li-type vermiculite as the first component of the swelling clay, Na-type montmorillonite or K-type montmorillonite as the second component of the swelling clay, and contained Na-type muscovite, K-type muscovite, or Na-type vermiculite that exhibited non-swelling properties upon heating, were capable of being handled in a 24-hour pure water immersion test after being heated at 300°C.

[0184] In particular, when comparing Experimental Example 1 containing talc as the third component with Experimental Example 14, Experimental Example 1 containing Na-type montmorillonite as the second component of the expanded clay was able to be treated in the 24-hour pure water immersion test after heating at 300°C, 600°C, and 700°C.

[0185] In contrast, in Experimental Example 14, which did not contain Na-type montmorillonite as the second component of the swelling clay, the sample collapsed in the 24-hour pure water immersion test after heating at 300° C. and 600° C.

[0186] Therefore, it was found that a sheet containing a Li-type clay layer as the first component of the swelling clay, smectite as the second component of the swelling clay, and clay that exhibits non-swelling properties upon heating has low water absorption and high handleability.

[0187] (About the mixing of raw materials)

[0188] Experimental Example 1, in which Li-type muscovite as the first component and Na-type montmorillonite as the second component were mixed, was compared with Experimental Examples 12 and 15, in which Na-type montmorillonite and Li-type muscovite were unmixed as single-element raw materials. In the 24-hour pure water immersion test after heating at 300°C, the water absorption rate of Experimental Example 1 was less than 40wt%, and it could be processed.

[0189] In contrast, in Experimental Example 12 using Na-type montmorillonite as a single substance and Experimental Example 15 using Li-type muscovite as a single substance, the water absorption rate was 40 wt % or more in the 24-hour pure water immersion test after heating at 300° C., and the samples were untreatable.

[0190] Therefore, it can be seen that the sheet in which the first component (Li-type muscovite) and the second component (smectite) are mixed has a low water absorption rate at 300° C. and has high water resistance.

[0191] (About the types of smectite)

[0192] The sheets of Experimental Examples 1 to 4, which contained Li-type muscovite as the first component, 10 wt% or more of Na-type montmorillonite or K-type montmorillonite as the second component, and talc as the third component, had a water absorption of 40% or less in a 24-hour pure water immersion test after being heated at 300°C for 24 hours. The samples did not disintegrate and could be handled.

[0193] In contrast, the sheets of Experimental Examples 16, 17, and 18, which contained Li-type muscovite as the first component of expanded clay, no expanded clay as the second component, and talc as the third component, collapsed in a 24-hour pure water immersion test after being heated at 300°C for 24 hours and could not be handled.

[0194] Therefore, it is understood that the sheet in which smectite as the second component is mixed with the first component (Li-type muscovite) has lower water absorption at 300° C. than sheets in which other clay materials are mixed, and has higher water resistance.

[0195] (About the mixing ratio when fillers are included)

[0196] The sheets of Experimental Examples 1 to 4 containing Li-type muscovite as the first component, Na-type montmorillonite as the second component, and talc as the third component had a water absorption of 20% or less in a 24-hour pure water immersion test after being heated at 700°C for 24 hours. The samples did not disintegrate and could be handled.

[0197] In particular, the sheets of Experimental Examples 1 to 3 containing 10 wt % or more of Na-type montmorillonite as the second component all had water absorption rates of 20% or less in a 24-hour pure water immersion test after being heated at 700°C and 600°C for 24 hours. The samples were not disintegrated and could be handled.

[0198] Among them, the sheet of Experimental Example 2 containing 20 wt % of Na-type montmorillonite had a water absorption of 20% or less in a 24-hour pure water immersion test after being heated at 300° C. for 24 hours.

[0199] Furthermore, the sheet of Experimental Example 3 containing 50 wt % of Na-type montmorillonite had a water absorption of 10% or less in a 24-hour pure water immersion test after being heated at 600° C. for 24 hours, which was the lowest among Experimental Examples 1 to 3.

[0200] Therefore, it can be seen that by adjusting the content of the second component, water resistance can be controlled according to the required temperature conditions.

[0201] (About the mixing ratio when filler is not included)

[0202] The sheets of Experimental Examples 1, 2, 5, and 8, which contained Li-type muscovite as the first component and 10 wt% to 20 wt% of Na-type montmorillonite as the second component, had a water absorption of 20% or less in a 24-hour pure water immersion test after being heated at 700°C and 600°C for 24 hours. The samples did not disintegrate and could be handled.

[0203] Here, the sheet of Experimental Example 1 containing talc as the third component had a water absorption rate of 40% or less at 300° C., and the sample could be handled without disintegration.

[0204] In contrast, the sheets of Experimental Example 8, which did not contain talc as the third component, had water absorption rates of 40% or more at 300° C. The samples disintegrated and could not be handled.

[0205] Therefore, it is understood that when no filler is included, a larger amount of the second component is required for water resistance at 300°C.

[0206] (Regarding the types of interlayer ions)

[0207] The sheets of Experimental Examples 1 and 4, which contained Li-type muscovite as the first component, 10 wt% of Na-type montmorillonite or K-type montmorillonite as the second component, and talc as the third component, had water absorption rates of less than 20% in a 24-hour pure water immersion test after being heated at 700°C and 600°C for 24 hours, and had water absorption rates of less than 40% in a 24-hour pure water immersion test after being heated at 300°C for 24 hours. The samples did not disintegrate and could be handled.

[0208] In contrast, the sheet of Experimental Example 11 containing Li-type montmorillonite as the second component had a water absorption of less than 40% in a 24-hour pure water immersion test after heating at 600°C for 24 hours, and disintegrated in a 24-hour pure water immersion test after heating at 300°C for 24 hours, making it unhandlable.

[0209] Therefore, it is understood that the sheet containing the expandable Na-type and K-type montmorillonite has a higher water resistance effect at 600° C. and 300° C. than the sheet containing the non-expandable Li-type montmorillonite.

[0210] (Regarding the types of Li-type clay layers)

[0211] In Experimental Examples 5 and 6, which contained no third component but Li-type muscovite or Li-type vermiculite as the first component and 20 wt% Na-type montmorillonite as the second component, the water absorption was 50% or less in a 24-hour pure water immersion test after heating at 600°C and 300°C for 24 hours, and the samples were handleable without disintegration. In particular, Experimental Example 5, which contained Li-type muscovite as the first component, had a water absorption of 40% or less in a 24-hour pure water immersion test after heating at 300°C, and a water absorption of 20% or less in a 24-hour pure water immersion test after heating at 600°C.

[0212] In contrast, in Experimental Example 19, which did not contain the third component but contained Li-type vermiculite as the first component in a simple substance, the water absorption rate was 20 wt % or more in the 24-hour pure water immersion test after heating at 700°C, and the treatment at 600°C and 300°C was unsusceptible.

[0213] Therefore, it is found that even when Li-type vermiculite is included as the first component, water resistance is achieved at 700° C., 600° C., and 300° C. It is also found that Li-type muscovite has a higher water resistance effect than Li-type vermiculite.

[0214] Furthermore, it was found that, as in Experimental Examples 10-1 to 10-4, even when Li-type vermiculite was included as the first component, Na-type montmorillonite as the second component, and talc as the third component, water resistance was achieved. In particular, Experimental Examples 10-1 and 10-2 showed high water resistance at 700°C, 600°C, and 300°C.

[0215] (Manufacturability)

[0216] The sheets of Experimental Examples 1 to 10 and 10-1 to 10-4, which contained a Li-type clay layer as the first component of the swelling clay, smectite as the second component of the swelling clay, and clay that exhibited non-swelling properties upon heating, showed no warping in the 0.5 mm thick sheet samples.

[0217] In the sheets of Experimental Examples 12 and 13 containing only smectite as the first component, warping was observed in the case of the 0.5 mm thick sheet samples.

[0218] Therefore, it can be seen that the sheet containing a Li-type clay layer as the first component of the swelling clay, smectite as the second component of the swelling clay, and clay that shows non-swelling properties when heated has no warping observed compared to the sheet containing only smectite, and has sufficient manufacturability as a sheet.

[0219] (About exhaust gas generation)

[0220] In the sheets of Experimental Examples 1 to 10 and 10-1 to 10-4, the first component (Li-type clay layer), the second component (smectite), and the third component (filler) are the main components and do not contain resins such as fluorine or binders, so it is found that the generation of outgassing is small.

[0221] (About insulation)

[0222] The sheets of Experimental Examples 1 to 5 and 7 to 9 containing Li-type muscovite as the first component and smectite as the second component have an iron content as low as 1.7 wt % or less, and therefore are found to have high insulation properties.

[0223] Furthermore, the sheets of Experimental Examples 10-1 to 10-4 containing Li-type vermiculite as the first component, smectite as the second component, and talc as the third component have an iron content as low as 6.0 wt % or less, and therefore are found to have high insulation properties.

[0224] <4. Summary>

[0225] It was found that a sheet containing a Li-type clay layer as the first component of the swelling clay, smectite as the second component of the swelling clay, and clay that exhibits non-swelling properties upon heating has low water absorption, high water resistance, and high handleability.

[0226] Furthermore, it was found that the sheet obtained by mixing Li-type muscovite and smectite had a low water absorption rate at 300° C. and had high water resistance.

[0227] Furthermore, it was found that by adjusting the content of smectite, water resistance can be controlled according to desired temperature conditions.

[0228] Furthermore, it was found that, in the case where no filler is included, the smectite content needs to be increased for water resistance at 300°C.

[0229] Furthermore, it was found that the sheet containing the expandable Na-type and K-type montmorillonite exhibited higher water resistance effects at 600° C. and 300° C. than the sheet containing the non-expandable Li-type montmorillonite.

[0230] Furthermore, it was found that when Li-type vermiculite was included as the first component, water resistance was also achieved at 700° C., 600° C., and 300° C. Furthermore, it was found that Li-type muscovite had a higher water resistance effect than Li-type vermiculite.

[0231] Furthermore, it was found that the sheet obtained by mixing Li-type vermiculite, smectite, and talc had a high water resistance effect at 700°C, 600°C, and 300°C.

[0232] Furthermore, it was found that a sheet comprising a Li-type clay layer as the first component of the swelling clay, smectite as the second component of the swelling clay, and clay that exhibits non-swelling properties upon heating showed no warping compared to a sheet comprising only smectite, indicating that the sheet had sufficient manufacturability.

[0233] By combining a Li-type clay layer capable of producing thick sheets with smectite, Li is supplied from the Li-type clay layer to the smectite during mixing, and heating causes Li to migrate from the interlayers of the smectite to the octahedral layers, thereby reducing hydrophilicity.

[0234] Therefore, it was found that the sheet had high water resistance and high handling properties, no warping was observed during sheet production, and sufficient performance as a sheet was achieved in a high-temperature environment.

[0235] Furthermore, since both the Li-type clay layer and smectite are expanded clays during sheet formation, the expanded clay layers are densely stacked to form a sheet. Furthermore, smectite is exfoliated very thinly, at approximately 1 nm, resulting in a higher number of particles per unit weight and a greater number of contact points between particles.

Claims

1. A sheet, characterized in that Contains expanded clay and non-expanded clay, The expanded clay comprises a first component and a second component having a structure different from that of the first component. The non-swelling clay is clay in which ions of the first component and the second component are exchanged in a dispersion medium, and exhibits non-swelling properties when heated.

2. The sheet according to claim 1, comprising the first component, the second component, and optionally a third component. The first component is the expanded clay whose interlayers are replaced by Li, The second component is Na-type montmorillonite or K-type montmorillonite, The third component is a filler. When the total weight of the first component, the second component, and the third component is set to 100 weight%, the content of the first component is greater than 25 weight% and less than 80 weight%, the content of the second component is greater than 10 weight% and less than 50 weight%, and the content of the third component is greater than 0 weight% and less than 80 weight%.

3. The sheet according to claim 1 or 2, wherein In a 24-hour pure water immersion test after heating at 300°C for 24 hours, the water absorption rate was 50% or less.

4. The sheet according to claim 1 or 2, wherein In a 24-hour pure water immersion test after heating at 300°C for 24 hours, the water absorption was 50% or less, and in a 24-hour pure water immersion test after heating at 600°C for 24 hours, the water absorption was 25% or less.

5. The sheet according to claim 1 or 2, wherein In a 24-hour pure water immersion test after heating at 300°C for 24 hours, the water absorption was 50% or less, and in a 24-hour pure water immersion test after heating at 700°C for 24 hours, the water absorption was 20% or less.

6. The sheet according to claim 1 or 2, wherein When the weight of the entire sheet is set to 100 weight %, the content of iron oxide is 6 weight % or less.

7. The sheet according to claim 1 or 2, wherein The first component is expanded muscovite, In the expanded muscovite, K between the layers of muscovite + At least a portion of the ions are Li + Ion exchange.

8. The sheet according to claim 2, wherein The filler includes talc, muscovite, sericite, kaolinite or fused silica. 9 . A sealing material comprising the sheet according to claim 1 . 10 . The sealing material according to claim 9 , which is used in a fuel cell or an electrolytic cell. 11 . A fuel cell or an electrolytic cell comprising the sealing material according to claim 10 .

12. A method for producing a sheet, which is the method for producing a sheet according to claim 2, wherein: The method for manufacturing the sheet comprises: a step of mixing the first component, the second component, and the third component to form a mixture; and A step of exchanging ions between the first component and the second component, and then forming the mixture into a sheet and heating it. 13 . A method for producing a sealing material, comprising the step of assembling the sheet produced by the method for producing a sheet according to claim 12 as a part of a gasket or a packing.

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