Gasket for pressure vessel and high-pressure gas tank

Abstract

A liner for a pressure vessel made of a fiber-reinforced composite material, the fiber-reinforced composite material including a cured product of a thermosetting resin or a thermosetting resin composition, and including continuous reinforcing fibers, and a high-pressure gas storage tank provided with the liner.

Description

Technical Field

[0001] The present invention relates to gaskets for pressure vessels and high-pressure gas storage tanks having the gaskets. Background Technology

[0002] In recent years, environmentally friendly natural gas vehicles (CNG vehicles) and fuel cell vehicles (FCVs) have become increasingly popular. Fuel cell vehicles use fuel cells as their power source and are indispensably equipped with a hydrogen refueling station that compresses hydrogen gas to high pressure and fills the vehicle.

[0003] High-pressure gas tanks, used as hydrogen refueling stations for fuel cell vehicles or as onboard fuel tanks for CNG vehicles and fuel cell vehicles, have traditionally been made of steel. However, lighter high-pressure gas tanks have been developed by using resin materials for the tank liner or outer layer. Lightening the onboard fuel tank offers advantages such as improved fuel efficiency for the vehicle.

[0004] As resin materials for constituting high-pressure gas storage tanks, resins with gas barrier properties and fiber-reinforced composite materials (FRPs) obtained by impregnating the resin with reinforcing fibers are known.

[0005] For example, Patent Document 1 discloses a resin liner and a high-pressure hydrogen tank having an FRP layer laminated on its outer peripheral surface. The resin liner comprises: a resin such as nylon as the main material with gas barrier properties, and an elastomer containing additives with hydrogen adsorption properties.

[0006] Patent document 2 discloses a pressure vessel having a liner and an outer layer of the liner, the outer layer being made of a composite material, and a liner made of the composite material comprising continuous fibers and a specified gas barrier polyamide resin impregnated into the continuous fibers.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2010-276146

[0010] Patent Document 2: International Publication No. 2016 / 084475 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] Gaskets for high-pressure gas storage tanks also require barrier properties and strength against the gas being stored, as well as heat resistance to withstand the temperature rise during tank use.

[0013] The resin gasket disclosed in Patent Literature 1 and the gasket for pressure vessels disclosed in Patent Literature 2 each use a thermoplastic resin. However, there is a limitation that it is difficult to impart heat resistance exceeding the melting point or glass transition temperature of the resin used to the gasket using a thermoplastic resin.

[0014] In addition, the gasket using a thermoplastic resin is generally heat-formed using a mold, which requires a series of forming cycles of heating and melting of the resin, filling into the mold, and cooling, and thus it is desirable to further improve the productivity. The thermoplastic resin having a low melting point or glass transition temperature can be heated and melted and filled into the mold in a shorter time, but the heat resistance of the resulting gasket becomes low.

[0015] An object of the present application is to provide a gasket for pressure vessels having light weight, gas barrier property, heat resistance, and high strength, and also excellent productivity, and a high-pressure gas storage tank provided with the gasket.

[0016] Means for solving the problem

[0017] The present inventors have found that a gasket for pressure vessels composed of a fiber-reinforced composite material containing a cured product of a thermosetting resin or a thermosetting resin composition and containing continuous reinforcing fibers can solve the above-described problems.

[0018] That is, the present application relates to the following [1] to [3].

[0019] [1] A gasket for pressure vessels composed of a fiber-reinforced composite material containing a cured product of a thermosetting resin or a thermosetting resin composition and containing continuous reinforcing fibers.

[0020] [2] A method for producing the gasket for pressure vessels described in the above [1], having the following steps:

[0021] a step of forming a towpreg composed of the aforementioned thermosetting resin or thermosetting resin composition and a bundle of continuous reinforcing fibers using a plating method or a cabling method.

[0022] [3] A high-pressure gas storage tank provided with the gasket for pressure vessels described in the above [1].

[0023] Effects of the invention

[0024] According to the present application, it is possible to provide a gasket for pressure vessels having light weight, gas barrier property for hydrogen and the like, heat resistance, and high strength, and also excellent productivity.

[0025] The pressure vessel liner of the present application has high gas barrier properties, heat resistance, and strength, and thus can be used directly as a pressure vessel such as a high-pressure gas storage tank without providing an outer layer. A high-pressure gas storage tank provided with the pressure vessel liner of the present application is suitable as a high-pressure gas storage tank for a vehicle, and can improve the fuel consumption of the vehicle due to the light weight. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a cross-sectional schematic view showing one embodiment of the pressure vessel liner of the present application.

[0027] Figure 2 is a perspective view showing one embodiment of the pressure vessel liner of the present application.

[0028] Figure 3 is a planar schematic view (partially enlarged view) showing one embodiment of the fiber-reinforced composite material constituting the pressure vessel liner of the present application.

[0029] Figure 4 is a planar schematic view (partially enlarged view) showing one embodiment of the fiber-reinforced composite material constituting the pressure vessel liner of the present application.

[0030] Figure 5 is a cross-sectional schematic view showing one embodiment of the high-pressure gas storage tank of the present application. DETAILED DESCRIPTION

[0031] [Pressure vessel liner]

[0032] The pressure vessel liner of the present application (hereinafter also simply referred to as "the liner of the present application") is composed of a fiber-reinforced composite material containing a cured product of a thermosetting resin or a thermosetting resin composition and containing continuous reinforcing fibers.

[0033] In the present specification, the "pressure vessel liner" refers to a member constituting the inner surface of a pressure vessel, i.e., directly contacting the contents of the pressure vessel. Therefore, a pressure vessel formed only of the pressure vessel liner of the present application is also included in the "liner" defined in the present application.

[0034] The liner of the present application has light weight, gas barrier properties for hydrogen and the like, heat resistance, and high strength by being composed of a fiber-reinforced composite material containing a cured product of a thermosetting resin or a thermosetting resin composition and containing continuous reinforcing fibers, and also has excellent productivity.

[0035] The reason is as follows. The existing known liner for pressure vessels containing a thermoplastic resin as a base resin and containing continuous reinforcing fibers has a limitation in imparting heat resistance because the thermoplastic resin necessarily has a melting point or a glass transition temperature (Tg). In contrast, the liner of the present application containing a cured product of a thermosetting resin or a thermosetting resin composition as a base resin can achieve higher heat resistance because the cured product has no Tg or, even if it has a Tg, the Tg is higher than that of a thermoplastic resin.

[0036] Further, in the molding of a liner containing a thermoplastic resin and continuous reinforcing fibers, it is necessary to perform molding after heating the material to a temperature exceeding the melting point or Tg of the thermoplastic resin, followed by cooling, and thus there is a tendency for the molding time to become long. In addition, a core rod, a mold, or the like for molding into a desired liner shape is required. In contrast, the liner of the present application using a thermosetting resin or a thermosetting resin composition and using continuous reinforcing fibers can also adopt a method of continuously molding without using a core rod, a mold, or the like after impregnating the thermosetting resin or the thermosetting resin composition into the continuous reinforcing fibers, if a plating method or the like described later is used. Therefore, the productivity of the liner of the present application is also excellent.

[0037] The liner of the present application is generally hollow as long as it has a space for filling a gas inside. The shape of the liner of the present application will be described with reference to the drawings.

[0038] Figure 1 is a cross-sectional schematic view showing one embodiment of the liner for pressure vessels of the present application, Figure 2 is a perspective view thereof. In Figure 1 and Figure 2 , the liner 100 has a cylindrical portion 1 and two dome portions 21 and 22 that seal both ends (1a and 1b) of the cylindrical portion 1.

[0039] Each of the dome portions 21 and 22 is hollow, and at least one of the dome portions (the dome portion 21 in Figure 1 ) is preferably provided with an opening portion 3 for joining a valve for pressure vessels or the like at the top of the dome portion.

[0040] In addition, in the case of a liner used in a pressure vessel provided with other members such as an outer layer, a dismounting portion or the like (not shown) for dismounting from the other members can be provided to the liner 100.

[0041] The liner 100 of the present application is composed of a fiber-reinforced composite material 10 containing a cured product of a thermosetting resin or a thermosetting resin composition and containing continuous reinforcing fibers.

[0042] The fiber-reinforced composite material 10 constituting the gasket 100 is preferably formed using a towpreg composed of a thermosetting resin or a thermosetting resin composition and continuous reinforcement fiber bundles from the viewpoints of gas barrier properties, strength, impact resistance, and productivity. By using this towpreg and performing molding using a plating method, a winding method, or the like, a gasket 100 composed of a fiber-reinforced composite material 10 having a spiral structure, a braid structure, a helical structure, or the like is obtained.

[0043] The fiber-reinforced composite material 10 constituting the gasket 100 preferably has a braid structure Figure 3 ) or a helical structure Figure 4 ) from the viewpoints of improving gas barrier properties, strength, impact resistance, and the like.

[0044] Figure 3 and Figure 4 are planar schematic views (partially enlarged views) that show one embodiment of the fiber-reinforced composite material 10 constituting the gasket 100, and are obtained by cutting out the region of A at the side surface of the gasket 100 shown in Figure 2 . As shown in Figure 3 and Figure 4 , the braid structure and the helical structure are structures obtained by gaplessly arranging the cured product 11 of a towpreg composed of a thermosetting resin or a thermosetting resin composition and continuous reinforcement fiber bundles in a braid shape or a helical shape, and thereby forming a hollow structure of the gasket 100.

[0045] From the viewpoints of gas barrier properties, strength, impact resistance, and productivity, it is preferable that at least the cylindrical portion 1 constituting the gasket 100 has a braid structure or a helical structure. The dome portions 21, 22 constituting the gasket 100 can also be composed of a fiber-reinforced composite material 10 having a braid structure or a helical structure, but are not particularly limited.

[0046] For example, if a towpreg composed of a thermosetting resin or a thermosetting resin composition and continuous reinforcement fiber bundles is used and molding is performed using a plating method, a gasket having a braid structure can be manufactured. In addition, if this towpreg is used to perform unidirectional plating or molding is performed using a winding method, a gasket having a helical structure can be manufactured. The gas barrier properties, strength, and impact resistance of a gasket having a braid structure or a helical structure are excellent, and are also advantageous from the viewpoint of productivity.

[0047] Figure 1 The gaskets 100 of Figure 2 can be formed by separately molding the cylindrical portion and the dome portion and joining them, or by integrally molding the cylindrical portion and the dome portion. From the viewpoint of gasket productivity, it is preferable that the cylindrical portion 1 is integrally molded with at least one dome portion.

[0048] If the yarn-adding or winding method is used, the cylindrical part and dome of the pad can be easily integrally formed using the aforementioned yarn prepreg.

[0049] When separately fabricating the dome of the padding, there are no particular limitations on the manufacturing method. It can be manufactured, for example, by hot pressing a prepreg obtained by impregnating the reinforcing fiber with a thermosetting resin or thermosetting resin composition using a mold. If the thermosetting resin and thermosetting resin composition used are solvent-free, it can also be manufactured by known molding methods such as Va-RTM (vacuum-assisted resin transfer molding), RTM (resin transfer molding), and HP-RTM (high-pressure resin transfer molding).

[0050] At this time, the thermosetting resin or thermosetting resin composition constituting the dome, as well as the reinforcing fibers, can be the same materials as those constituting the liner cylindrical portion.

[0051] Alternatively, when separately fabricating the dome of the padding, the dome can also be made using a thermoplastic resin or a thermoplastic resin composition. The dome can be made using a prepreg obtained by impregnating or laminating a thermoplastic resin or thermoplastic resin composition onto reinforcing fibers. Examples of such thermoplastic resins include, for instance, polyamide resins, polyester resins, polyolefin resins, polyimide resins, polycarbonate resins, polyetherimide resins, polyamideimide resins, polyphenylene etherimide resins, polyphenylene sulfide resins, polysulfone resins, polyethersulfone resins, polyarylate resins, liquid crystal polymers, polyetheretherketone resins, polyetherketone resins, polyetherketoneketone resins, polyetheretherketoneketone resins, polybenzimidazole resins, etc., and one or more of these can be used.

[0052] The thickness of the pad is 100. Figure 1 The thickness of the t in the pressure vessel can be appropriately selected based on the capacity, shape, and thickness of the continuous reinforcing fibers or the outer diameter of the fiber bundle used. When used in a pressure vessel, from the viewpoint of ensuring sufficient barrier properties and pressure resistance for gases such as hydrogen, the thickness of the gasket is preferably 100 μm or more, more preferably 200 μm or more, and even more preferably 400 μm or more. From the viewpoint of miniaturization and weight reduction of the gasket and pressure vessel, it is preferably 60 mm or less, more preferably 40 mm or less.

[0053] <Thermosetting resins, thermosetting resin compositions>

[0054] The thermosetting resin used in the gasket of the present application is not particularly limited as long as it is a resin that can be cured by heating. In addition, the thermosetting resin composition used in the present application is a composition containing the thermosetting resin.

[0055] As the thermosetting resin, at least one selected from the group consisting of an epoxy resin, a phenol resin, a urea resin, a melamine resin, an unsaturated polyimide resin, a silicone resin, a urethane resin, a casein resin, a furan resin, an alkyd resin, and a xylene resin can be exemplified. Among these, from the viewpoint of ease of impregnation in the continuous reinforcing fiber and the viewpoint of heat resistance, strength, and barrier properties of the resulting cured product against gases such as hydrogen, an epoxy resin is preferred.

[0056] As the epoxy resin composition containing an epoxy resin as the thermosetting resin, a two-component curable epoxy resin composition containing an epoxy resin (a compound containing an epoxy group) as the main agent and an epoxy resin curing agent can be exemplified.

[0057] From the viewpoint of obtaining higher gas barrier properties and impact resistance, the thermosetting resin composition is preferably an epoxy resin composition, which is preferably an epoxy resin composition containing an epoxy resin (A) and an epoxy resin curing agent (B) containing a reaction product (X) of the following component (x1) and component (x2).

[0058] (x1) at least one selected from the group consisting of m-xylylenediamine and p-xylylenediamine

[0059] (x2) at least one selected from the group consisting of unsaturated carboxylic acids and derivatives thereof represented by the following general formula (1)

[0060]

[0061] (In formula (1), R 1 , R 2 each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms.)

[0062] From the viewpoint of improving impregnation in the continuous reinforcing fiber, the epoxy resin composition preferably further contains a solvent.

[0063] Hereinafter, the suitable mode of the thermosetting resin composition used in the present application, i.e., the above-described epoxy resin composition, will be described in detail.

[0064] (Epoxy resin (A))

[0065] The epoxy resin (A) (hereinafter also referred to simply as "component (A)") is not particularly limited as long as it is a multifunctional epoxy resin having 2 or more epoxy groups, and a multifunctional epoxy resin containing an aromatic ring or an alicyclic structure in the molecule is preferred in view of exhibiting high gas barrier properties.

[0066] As specific examples of the multifunctional epoxy resin, at least one resin selected from the group consisting of an epoxy resin having a glycidylamino group derived from m-xylylenediamine, an epoxy resin having a glycidylamino group derived from p-xylylenediamine, an epoxy resin having a glycidylamino group derived from 1,3-bis(aminomethyl)cyclohexane, an epoxy resin having a glycidylamino group derived from 1,4-bis(aminomethyl)cyclohexane, an epoxy resin having a glycidylamino group derived from diaminodiphenylmethane, an epoxy resin having a glycidylamino group and / or a glycidyloxy group derived from p-aminophenol, an epoxy resin having a glycidyloxy group derived from bisphenol A, an epoxy resin having a glycidyloxy group derived from bisphenol F, an epoxy resin having a glycidyloxy group derived from phenol novolak, and an epoxy resin having a glycidyloxy group derived from m-phenylenediamine can be exemplified. In order to improve various properties such as softness, impact resistance, and moisture heat resistance, two or more of the above-mentioned epoxy resins can also be used in an appropriate ratio.

[0067] Among the above, from the viewpoint of gas barrier properties, as the epoxy resin (A), at least one selected from the group consisting of an epoxy resin having a glycidylamino group derived from m-xylylenediamine, an epoxy resin having a glycidylamino group derived from p-xylylenediamine, and an epoxy resin having a glycidyloxy group derived from bisphenol F is preferred as a main component, and an epoxy resin having a glycidylamino group derived from m-xylylenediamine is more preferred as a main component.

[0068] Note that the "main component" referred to here means that other components can be contained within the scope of the gist of the present application, and means that it is preferably 50 to 100% by mass of the whole, more preferably 70 to 100% by mass, and further preferably 90 to 100% by mass.

[0069] (Epoxy Resin Curing Agent (B))

[0070] From the viewpoint of exhibiting high gas barrier properties and impact resistance, the epoxy resin curing agent (B) (hereinafter also referred to simply as "component (B)") contains an epoxy resin curing agent (B) containing a reaction product (X) of the following component (x1) and component (x2).

[0071] (x1) at least one selected from the group consisting of m-xylylenediamine and p-xylylenediamine

[0072] (x2) at least one selected from the group consisting of unsaturated carboxylic acids and derivatives thereof represented by the following general formula (1)

[0073]

[0074] (In formula (1), R 1 , R 2 each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms.)

[0075] [Reaction product (X)]

[0076] The reaction product (X) is a reaction product of the aforementioned component (x1) and component (x2).

[0077] The component (x1) is used from the viewpoint of gas barrier properties, and is preferably m-xylylenediamine from the viewpoint of gas barrier properties. The component (x1) can be used alone as one kind, or can be used in combination as two kinds.

[0078] The component (x2) is at least one selected from the group consisting of unsaturated carboxylic acids and derivatives thereof represented by the aforementioned general formula (1). From the viewpoint of exhibiting high gas barrier properties and impact resistance, R 1 is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, further preferably a hydrogen atom or a methyl group, and still further preferably a hydrogen atom.

[0079] In addition, from the viewpoint of exhibiting high gas barrier properties and impact resistance, R 2 is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, further preferably a hydrogen atom or a methyl group, and still further preferably a hydrogen atom.

[0080] As the derivatives of the unsaturated carboxylic acid represented by the aforementioned general formula (1), for example, esters, amides, anhydrides, and acid chlorides of the unsaturated carboxylic acid can be exemplified. As the esters of the unsaturated carboxylic acid, alkyl esters are preferred, and the number of carbon atoms of the alkyl group is preferably 1 to 6, more preferably 1 to 3, and further preferably 1 to 2, from the viewpoint of obtaining good reactivity.

[0081] As the unsaturated carboxylic acid and derivatives thereof represented by the aforementioned general formula (1), there can be mentioned unsaturated carboxylic acids such as acrylic acid, methacrylic acid, α-ethylacrylic acid, α-propylacrylic acid, α-isopropylacrylic acid, α-n-butylacrylic acid, α-tert-butylacrylic acid, α-pentylacrylic acid, α-phenylacrylic acid, α-benzylacrylic acid, crotonic acid, 2-pentenoic acid, 2-hexenoic acid, 4-methyl-2-pentenoic acid, 2-heptenoic acid, 4-methyl-2-hexenoic acid, 5-methyl-2-hexenoic acid, 4,4-dimethyl-2-pentenoic acid, 4-phenyl-2-butenoic acid, cinnamic acid, o-methylcinnamic acid, m-methylcinnamic acid, p-methylcinnamic acid, 2-octenoic acid, and the like; and esters, amides, anhydrides, acid chlorides, and the like thereof.

[0082] Among the above, from the viewpoint of exhibiting high gas barrier properties and impact resistance, component (x2) is preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, and derivatives thereof, more preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, and alkyl esters thereof, further preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, and alkyl esters thereof, still further preferably an alkyl ester of acrylic acid, and yet further preferably methyl acrylate.

[0083] Component (x2) can be used singly or in combination of two or more.

[0084] In the case where an unsaturated carboxylic acid, an ester, an amide is used as component (x2), the reaction of component (x1) with component (x2) is carried out by mixing component (x1) with component (x2) at 0 to 100°C, more preferably at 0 to 70°C, and then carrying out Michael addition reaction and amide group formation reaction based on dehydration, dealcoholization, and deamination at 100 to 300°C, preferably at 130 to 250°C.

[0085] In this case, in the amide group formation reaction, in order to complete the reaction, a non-reactive solvent can be used as needed for dilution. Further, as a dehydrating agent, a dealcoholizing agent, a catalyst such as a phosphite can be added.

[0086] On the other hand, in the case where an acid anhydride or an acid chloride of an unsaturated carboxylic acid is used as component (x2), the reaction is carried out by mixing at 0 to 150°C, preferably at 0 to 100°C, and then carrying out Michael addition reaction and amide group formation reaction. In this case, in the amide group formation reaction, in order to complete the reaction, a non-reactive solvent can be used as needed for dilution. Further, a tertiary amine such as pyridine, methylpyridine, dimethylpyridine, and trialkylamine can be added.

[0087] The amido site formed by the reaction of component (x1) with component (x2) has high cohesive force, and therefore, the cured product of the epoxy resin composition obtained using the epoxy resin curing agent (B) containing the reaction product (X) of component (x1) with component (x2) has high gas barrier properties and good adhesion to a reinforcing fiber.

[0088] In the reaction product (X), the reaction molar ratio of component (x2) to component (x1) [(x2) / (x1)] is preferably in the range of 0.3 to 1.0, more preferably in the range of 0.6 to 1.0. If the above reaction molar ratio is 0.3 or more, a sufficient amount of amido group is generated in the epoxy resin curing agent, and high levels of gas barrier properties and adhesion to a reinforcing fiber are exhibited. On the other hand, if the above reaction molar ratio is in the range of 1.0 or less, the amount of amino group required for reaction with the epoxy group in the epoxy resin (A) is sufficient, and the heat resistance and solubility in an organic solvent are also excellent.

[0089] The reaction product (X) can be a reaction product of the aforementioned component (x1) with component (x2), and further with at least one compound selected from the group consisting of component (x3), component (x4), and component (x5).

[0090] (x3) is at least one selected from the group consisting of a monocarboxylic acid represented by R 3 -COOH and a derivative thereof (R 3 represents a hydrogen atom, an alkyl group having 1 to 7 carbon atoms optionally having a hydroxyl group, or an aryl group having 6 to 12 carbon atoms.

[0091] (x4) is a cyclic carbonate

[0092] (x5) is a mono-epoxide compound having 2 to 20 carbon atoms

[0093] R 3 -COOH and a derivative thereof are used as needed from the viewpoint of reducing the reactivity of the epoxy resin curing agent (B) containing the reaction product (X) with the epoxy resin (A), improving the handling properties, pot life, and the like.

[0094] R 3 represents a hydrogen atom, an alkyl group having 1 to 7 carbon atoms optionally having a hydroxyl group, or an aryl group having 6 to 12 carbon atoms, and R 3 is preferably an alkyl group having 1 to 3 carbon atoms or a phenyl group.

[0095] In addition, R 3-COOH represents a monocarboxylic acid derivative, and examples thereof include an ester, an amide, an anhydride, and an acid chloride of the carboxylic acid. As the ester of the carboxylic acid, an alkyl ester is preferred, and the number of carbon atoms of the alkyl group is preferably from 1 to 6, more preferably from 1 to 3, and further preferably from 1 to 2.

[0096] As component (x3), a monocarboxylic acid such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, glycolic acid, and benzoic acid, and a derivative thereof can be exemplified.

[0097] Component (x3) can be used alone or in combination with two or more kinds.

[0098] The cyclic carbonate of component (x4) is used as needed from the viewpoint of reducing the reactivity of the epoxy resin curing agent (B) containing the reaction product (X) with the epoxy resin (A), improving the handling properties, pot life, and the like.

[0099] From the viewpoint of the reactivity with component (x1), component (x4) is preferably a cyclic carbonate having a ring size of six or less. Examples thereof include ethylene carbonate, propylene carbonate, glycerol carbonate, 1,2-butylene carbonate, vinylene carbonate, 4-vinyl-1,3-dioxolan-2-one, 4-methoxymethyl-1,3-dioxolan-2-one, and 1,3-dioxan-2-one. Among these, from the viewpoint of gas barrier properties, at least one selected from the group consisting of ethylene carbonate, propylene carbonate, and glycerol carbonate is preferred.

[0100] Component (x4) can be used alone or in combination with two or more kinds.

[0101] The monoepoxy compound of component (x5) is a monoepoxy compound having a carbon number of from 2 to 20, and is used as needed from the viewpoint of reducing the reactivity of the epoxy resin curing agent (B) containing the reaction product (X) with the epoxy resin (A), improving the handling properties, pot life, and the like. From the viewpoint of gas barrier properties, the monoepoxy compound of component (x5) is preferably a monoepoxy compound having a carbon number of from 2 to 10, and more preferably a compound represented by the following formula (2).

[0102]

[0103] (In formula (2), R 4 represents a hydrogen atom, an alkyl group having a carbon number of from 1 to 8, an aryl group, a chloromethyl group, or R 5 -O-CH2-, R 5 represents a phenyl group or a benzyl group.)

[0104] As the monocyclic epoxy compound represented by the aforementioned formula (2), for example, oxirane, propylene oxide, 1,2-epoxybutane, epoxystyrene, epichlorohydrin, phenyl glycidyl ether, and benzyl glycidyl ether can be given.

[0105] The component (x5) can be used alone or in combination with two or more.

[0106] In the case where the reaction product (X) uses the component (x3), the component (x4), or the component (x5), any one compound selected from the group consisting of the component (x3), the component (x4), and the component (x5) can be used alone, or two or more can be used in combination.

[0107] Note that the reaction product (X) can be a reaction product obtained by further reacting the aforementioned components (x1) to (x5) with other components within a range not impairing the effects of the present application. As the other components mentioned here, for example, aromatic dicarboxylic acids or derivatives thereof can be given.

[0108] The amount of the "other components" is preferably 30% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less, of the total amount of the reaction components constituting the reaction product (X).

[0109] The reaction product of the component (x1) and the component (x2), and further at least one compound selected from the group consisting of the component (x3), the component (x4), and the component (x5) is obtained by using at least one compound selected from the group consisting of the component (x3), the component (x4), and the component (x5) in combination with the component (x2), and reacting with the component (x1) which is a polyamine compound. In this reaction, the components (x2) to (x5) can be added in any order and reacted with the component (x1), or the components (x2) to (x5) can be mixed and reacted with the component (x1).

[0110] The reaction of the component (x1) and the component (x3) can be performed using the same conditions as the reaction of the component (x1) and the component (x2). In the case where the component (x3) is used, the component (x2) can be mixed with the component (x3) and reacted with the component (x1), or the component (x1) can be first reacted with the component (x2), and then reacted with the component (x3).

[0111] On the other hand, in the case where the component (x4) and / or the component (x5) is used, it is preferable to first react the component (x1) with the component (x2), and then react with the component (x4) and / or the component (x5).

[0112] The reaction of component (x1) with component (x4) and / or component (x5) is carried out by mixing component (x1) with component (x4) and / or component (x5) at 25–200°C and carrying out an addition reaction at 30–180°C, preferably 40–170°C. Alternatively, catalysts such as sodium methoxide, sodium ethoxide, and potassium tert-butoxide can be used as needed.

[0113] In the above reaction, to promote the reaction, components (x4) and / or components (x5) may be melted or diluted with a non-reactive solvent as needed.

[0114] When the reaction product (X) is the reaction product of the aforementioned components (x1) and (x2), and further with at least one compound selected from the group consisting of the aforementioned components (x3), (x4), and (x5), for the same reasons as above, the reaction molar ratio of component (x2) to the aforementioned component (x1) [(x2) / (x1)] is preferably in the range of 0.3 to 1.0, more preferably in the range of 0.6 to 1.0. On the other hand, the reaction molar ratio of the aforementioned components (x3), (x4), and (x5) to component (x1) [{(x3)+(x4)+(x5)} / (x1)] is preferably in the range of 0.05 to 3.1, more preferably in the range of 0.07 to 2.5, and even more preferably in the range of 0.1 to 2.0.

[0115] From the viewpoints of gas barrier properties, operability, and pot life, the reaction molar ratio of components (x2) to (x5) relative to component (x1) [{(x2)+(x3)+(x4)+(x5)} / (x1)] is preferably in the range of 0.35 to 2.5, and more preferably in the range of 0.35 to 2.0.

[0116] The epoxy resin curing agent (B) may contain curing agent components other than the reaction product (X). "Curing agent components other than the reaction product (X)" refers to components having two or more functional groups that can react with the epoxy groups in the epoxy resin (A) and other than the reaction product (X). From the viewpoint of reactivity with epoxy resin (A) and gas barrier properties, preferred components include polyamine compounds having two or more amino groups in their molecules other than component (x1) and modified polyamine compounds.

[0117] From the viewpoint of exhibiting high gas barrier properties and impact resistance, the epoxy resin curing agent (B) preferably has a high content of reaction product (X). From this viewpoint, the content of reaction product (X) in the epoxy resin curing agent (B) is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and even more preferably 90% by mass or more. Furthermore, the upper limit is 100% by mass.

[0118] The mixing ratio of the epoxy resin (A) to the epoxy resin curing agent (B) in the epoxy resin composition can generally be the standard mixing range when a cured product is produced by the reaction of the epoxy resin and the epoxy resin curing agent. Specifically, the ratio of the number of active amine hydrogens in the epoxy resin curing agent (B) to the number of epoxy groups in the epoxy resin (A) (number of active amine hydrogens in the epoxy resin curing agent (B) / number of epoxy groups in the epoxy resin (A)) is preferably in the range of 0.2 to 12.0. From the viewpoint of exhibiting high gas barrier properties and impact resistance, the number of active amine hydrogens in the epoxy resin curing agent (B) / number of epoxy groups in the epoxy resin (A) is more preferably in the range of 0.4 to 10.0, further preferably in the range of 0.6 to 8.0, more further preferably in the range of 0.9 to 6.0, still further preferably more than 1.0 and 5.0 or less.

[0119] From the viewpoint of further improving impact resistance, the number of active amine hydrogens in the epoxy resin curing agent (B) / number of epoxy groups in the epoxy resin (A) is more further preferably 1.1 or more, still further preferably 1.4 or more, still further preferably 2.0 or more, and from the viewpoint of further improving hydrogen barrier properties, the number of active amine hydrogens in the epoxy resin curing agent (B) / number of epoxy groups in the epoxy resin (A) is more preferably 4.0 or less, more further preferably 3.2 or less.

[0120] (Solvent)

[0121] From the viewpoint of achieving low viscosity of the composition and improving impregnation in continuous reinforcing fibers, the epoxy resin composition preferably further contains a solvent.

[0122] As the solvent, a non-reactive solvent is preferred, and as specific examples thereof, alcohol-based solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-propoxy-2-propanol; ester-based solvents such as ethyl acetate, butyl acetate; ketone-based solvents such as acetone, methyl isobutyl ketone; ether-based solvents such as diethyl ether, diisopropyl ether; hydrocarbon-based solvents such as toluene; and the like can be used, and one or two or more kinds thereof can be used.

[0123] From the viewpoint of solubility of the epoxy resin (A) and the epoxy resin curing agent (B) and the viewpoint of ease of solvent removal, as the solvent, at least one selected from the group consisting of alcohol-based solvents, ester-based solvents, and hydrocarbon-based solvents having 8 or less carbon atoms is preferred, at least one selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, ethyl acetate, and toluene is more preferred, and at least one selected from the group consisting of methanol and ethyl acetate is further preferred.

[0124] In the case where the epoxy resin composition contains a solvent, the content thereof is not particularly limited, and from the viewpoint of improving the impregnation property of the epoxy resin composition into the continuous reinforcing fiber, it is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, more further preferably 20% by mass or more, still more further preferably 30% by mass or more, still more further preferably 40% by mass or more, and from the viewpoint of ease of removal of the solvent, it is preferably 95% by mass or less, more preferably 90% by mass or less, further preferably 80% by mass or less, more further preferably 70% by mass or less.

[0125] The epoxy resin composition can be further compounded, as necessary, with additives such as a thermosetting resin other than the epoxy resin (A), a coupling agent, a reactive diluent, a non-reactive diluent other than the aforementioned solvent, a curing accelerator, a wetting agent, an adhesion promoter, an antifoaming agent, an antirust agent, a lubricant, a pigment, an oxygen trapping agent, an ultraviolet absorber, an antioxidant, and the like, within a range not impairing the effects of the present application.

[0126] In the case where the epoxy resin composition contains the aforementioned additives, the total content of the aforementioned additives in the composition is preferably 20.0 parts by mass or less, more preferably 0.001 to 15.0 parts by mass, relative to 100 parts by mass of the total amount of the epoxy resin (A) and the epoxy resin curing agent (B).

[0127] wherein, from the viewpoint of obtaining the effects of the present application, the total content of the epoxy resin (A) and the epoxy resin curing agent (B) in the solid components of the epoxy resin composition is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, more further preferably 85% by mass or more, and the upper limit is 100% by mass. The "solid components of the epoxy resin composition" refer to the components of the epoxy resin composition after removal of water and solvent.

[0128] The epoxy resin composition can be produced by, for example, compounding a prescribed amount of each of the epoxy resin (A), the epoxy resin curing agent (B), the solvent, and the additives used as necessary, and then stirring and mixing using a publicly known method and apparatus.

[0129] <Continuous reinforcing fiber>

[0130] The continuous reinforcing fiber used in the gasket of the present application is a reinforcing fiber having a fiber length of 100 mm or more.

[0131] As the shape of the continuous reinforcing fiber, a tow, a sheet, a tape, or the like can be exemplified, and as the continuous reinforcing fiber constituting a sheet or a tape, a unidirectional (UD) material, a woven fabric, a nonwoven fabric, or the like can be exemplified.

[0132] From the viewpoint of forming the gasket of the present application using the plating method, the winding method, or the like described later, as the shape of the continuous reinforcing fiber, a tow or a tape is preferable, and a tow (continuous reinforcing fiber tow) is more preferable. From the viewpoint of easily obtaining high strength and high elastic modulus, the number of fiber tows (filament count) constituting the tow is preferably 3K to 50K, and more preferably 6K to 40K.

[0133] The average fiber length of the continuous reinforcing fiber tow is not particularly limited, and from the viewpoint of forming processability, it is preferably 1 to 10,000 m, and more preferably 100 to 10,000 m.

[0134] From the viewpoint of forming processability, and the viewpoint of easily obtaining high strength and high elastic modulus, the average denier of the continuous reinforcing fiber tow is preferably 50 to 2,000 tex (g / 1,000 m), more preferably 200 to 1,500 tex, and further preferably 500 to 1,500 tex.

[0135] In addition, the average tensile elastic modulus of the continuous reinforcing fiber tow is preferably 50 to 1,000 GPa.

[0136] As the kind of the continuous reinforcing fiber, inorganic fibers such as glass fibers, carbon fibers, metal fibers, boron fibers, basalt fibers, and ceramic fibers; and organic fibers such as aramid fibers, polyoxymethylene fibers, aramid fibers, poly-p-phenylene benzobisoxazole fibers, and ultra-high molecular weight polyethylene fibers can be listed. Among these, from the viewpoint of obtaining high strength, as the continuous reinforcing fiber, inorganic fibers are preferable, and from the viewpoint of light weight and high strength, high elastic modulus, at least one kind selected from the group consisting of glass fibers, carbon fibers, and basalt fibers is more preferable, and further, carbon fibers are preferable.

[0137] As the carbon fiber, polyacrylonitrile-based carbon fibers, pitch-based carbon fibers, and the like can be listed. In addition, carbon fibers derived from plant-derived raw materials such as lignin and cellulose can also be used.

[0138] The continuous reinforcing fiber used in the present application can be treated with a treating agent. As the treating agent, a surface treating agent or a bundling agent can be exemplified.

[0139] As the surface treating agent described above, a silane coupling agent is preferable. As the silane coupling agent, a silane coupling agent having a vinyl group, a silane coupling agent having an amino group, a silane coupling agent having an epoxy group, a silane coupling agent having a (meth)acryloyl group, a silane coupling agent having a mercapto group, and the like can be listed.

[0140] As the above-mentioned sizing agent, for example, urethane-based sizing agents, epoxy-based sizing agents, acrylic-based sizing agents, polyester-based sizing agents, vinyl ester-based sizing agents, polyolefin-based sizing agents, polyether-based sizing agents, and carboxylic acid-based sizing agents can be exemplified, and one kind or two or more kinds in combination thereof can be used. As the sizing agent obtained by combining two or more kinds, for example, urethane / epoxy-based sizing agents, urethane / acrylic-based sizing agents, urethane / carboxylic acid-based sizing agents, and the like can be exemplified.

[0141] Among the above, from the viewpoint of improving the interfacial adhesion to the cured product of the thermosetting resin, especially to the cured product of the epoxy resin composition, further improving the strength and impact resistance of the obtained gasket, the continuous reinforcing fiber is preferably treated with one or more selected from the group consisting of urethane-based sizing agents, epoxy-based sizing agents, and urethane / epoxy-based sizing agents, and more preferably treated with an epoxy-based sizing agent.

[0142] From the viewpoint of improving the interfacial adhesion to the cured product of the thermosetting resin or the thermosetting resin composition, further improving the strength and impact resistance of the obtained gasket, the amount of the above-mentioned treating agent with respect to the continuous reinforcing fiber is preferably 0.001 to 5% by mass, more preferably 0.1 to 3% by mass, and further preferably 0.5 to 2% by mass.

[0143] As the continuous reinforcing fiber, a commercially available product can also be used. As the commercially available product of the carbon fiber as the continuous reinforcing fiber, for example, each series of Torayca yarn "T300", "T300B", "T400HB", "T700SC", "T800SC", "T800HB", "T830HB", "T1000GB", "T100GC", "M35JB", "M40JB", "M46JB", "M50JB", "M55J", "M55JB", "M60JB", "M30SC", "Z600" manufactured by Toray Industries, Inc.; Torayca cloth "CO6142", "CO6151B", "CO6343", "CO6343B", "CO6347B", "CO6644B", "CK6244C", "CK6273C", "CK6261C", "UT70" series, "UM46" series, "BT70" series, and the like can be exemplified.

[0144] The content of the continuous reinforcing fiber in the gasket of the present application is not particularly limited, and the volume fraction (Vf) of the continuous reinforcing fiber is preferably in the range of 10% or more, more preferably 20% or more, further preferably 30% or more, and still further preferably 40% or more from the viewpoint of obtaining high strength and high elastic modulus. In addition, the volume fraction is preferably in the range of 98% or less, more preferably 95% or less, further preferably 80% or less, and still further preferably 70% or less from the viewpoint of gas barrier properties and impact resistance.

[0145] The volume fraction (Vf) of the continuous reinforcing fiber in the gasket can be calculated according to the following formula.

[0146] Vf = {mass (g) of the continuous reinforcing fiber in the gasket / specific gravity of the continuous reinforcing fiber} ÷ {mass (g) of the gasket / specific gravity of the gasket} x 100

[0147] The gasket of the present application is composed of a fiber-reinforced composite material, and any layer such as a protective layer, a paint layer, a layer containing a rust preventive, and the like can be provided as needed.

[0148] In the gasket of the present application, the total content of the cured product of the thermosetting resin or thermosetting resin composition and the continuous reinforcing fiber is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more from the viewpoint of obtaining the effects of the present application, and the upper limit is 100% by mass.

[0149] [Method for manufacturing a gasket for pressure containers]

[0150] The method for manufacturing a gasket for pressure containers of the present application (hereinafter also referred to simply as "the manufacturing method of the present application") is not particularly limited. For example, a method in which a prepreg composed of the aforementioned thermosetting resin or thermosetting resin composition and continuous reinforcing fiber is used, and molding is performed using a plating method, a braiding method, a 3D printer method, or the like can be exemplified.

[0151] From the viewpoint of molding a gasket having the aforementioned braid structure or spiral structure, the viewpoint of integrally molding a cylindrical portion and at least one dome portion of the gasket, and the viewpoint of productivity, the method for manufacturing a gasket for pressure containers of the present application preferably has a step of molding a tow prepreg composed of a thermosetting resin or thermosetting resin composition and a continuous reinforcing fiber bundle using a plating method or a braiding method. From the viewpoint that the gasket can be molded without using a mandrel or the like, it is more preferable to use a plating method.

[0152] The tow prepreg is obtained by impregnating the aforementioned thermosetting resin or thermosetting resin composition into a continuous reinforcing fiber bundle. As the thermosetting resin or thermosetting resin composition, it is preferable to use the aforementioned epoxy resin composition, and from the viewpoint of improving the impregnability in the continuous reinforcing fiber bundle, the composition more preferably contains a solvent.

[0153] The method of impregnating the thermosetting resin or thermosetting resin composition into the continuous reinforcing fiber is not particularly limited, and a publicly known method can be used. For example, a method in which a continuous reinforcing fiber bundle drawn out from a roll is dipped in a resin bath filled with the thermosetting resin or thermosetting resin composition, and the continuous reinforcing fiber bundle impregnated with the thermosetting resin or thermosetting resin composition is pulled up from the resin bath can be mentioned. Thereafter, a process of removing the excess thermosetting resin or thermosetting resin composition using a squeeze roll or the like can also be performed.

[0154] The impregnation of the thermosetting resin or thermosetting resin composition can also be performed under a pressurized condition or a reduced pressure condition as needed.

[0155] In the case where the thermosetting resin composition contains a solvent, the continuous reinforcing fiber impregnated with the thermosetting resin composition is then subjected to a drying process to remove the solvent. The drying conditions in the drying process are not particularly limited, and conditions under which the solvent can be removed and the thermosetting resin in the composition does not excessively cure are preferred. From this viewpoint, for example, the drying temperature can be selected within a range of 30 to 100°C, and the drying time can be selected within a range of 10 seconds to 5 minutes.

[0156] The above-described drying process can be performed using a hot air drier, a heater, a heating roll, a hot plate, or the like, and by a publicly known method. For example, a method in which the continuous reinforcing fiber bundle is caused to travel in a heating atmosphere based on a hot air drier, a heater, or the like; a method in which the continuous reinforcing fiber bundle is caused to contact a heating body such as a heating roll or a hot plate; and the like can be mentioned. Among these, a method using a hot air drier is preferred.

[0157] The obtained tow prepreg can be temporarily wound onto a bobbin, and from the viewpoint of improving productivity, it is preferred that the tow prepreg be continuously supplied to the plying method or the winding method without being wound.

[0158] The forming using the tow prepreg and based on the plying method and the winding method can be performed using a braiding machine or a winding device, and by a publicly known method.

[0159] In the case of using the plying method, for example, a core rod made of metal or the like is used, and the aforementioned tow prepreg is plied in one direction or plied in a manner to form a braid structure by a braiding machine, and a prepreg in the shape of a cylinder or a shape in which one end or both ends are sealed by a dome is formed. Subsequently, a process of heating the prepreg to cause the thermosetting resin to cure is performed.

[0160] The heating is performed at a temperature and for a time sufficient for causing the thermosetting resin contained in the prepreg to cure, and by a publicly known method. From the viewpoint of improving productivity, the heating temperature is set to a range of 80 to 140°C, and preferably to a range of 80 to 120°C, and the heating time is set to a range of 10 minutes to 5 hours.

[0161] Note that, in the plaiting method, the tows are plaited without using a mandrel, and a cylindrical prepreg or a prepreg having a shape in which one end or both ends are sealed by a dome can be formed.

[0162] In the case of using the winding method, for example, the aforementioned tows are wound in a spiral shape on the outer surface of a mandrel made of metal or the like using a winding device, and a cylindrical prepreg or a prepreg having a shape in which one end or both ends are sealed by a dome is formed. Subsequently, the prepreg is heated to cure the thermosetting resin, as in the aforementioned case.

[0163] In the case of forming only the cylindrical portion of the gasket or a member in which only one end of the gasket cylindrical portion is sealed by using the plaiting method and the winding method, the other end or both ends of the cylindrical portion can be joined to a dome prepared separately and sealed, thereby manufacturing the gasket of the present application.

[0164] The gasket of the present application is a gasket for a pressure vessel, and from the viewpoint of the effectiveness of the present application, the pressure vessel is preferably a high-pressure gas storage tank. The gas to be stored in the high-pressure gas storage tank can be a gas at 25°C and 1 atm, and examples thereof include hydrogen, oxygen, carbon dioxide, nitrogen, argon, LPG, Freon substitutes, and methane, in addition to hydrogen. Among these, from the viewpoint of the effectiveness of the present application, hydrogen is preferred.

[0165] [High-pressure gas storage tank]

[0166] The high-pressure gas storage tank of the present application has the aforementioned gasket for a pressure vessel. The high-pressure gas storage tank of the present application has the aforementioned gasket for a pressure vessel, and thus has excellent barrier properties against gases such as hydrogen, and is also lightweight, has excellent pressure resistance, and has excellent impact resistance.

[0167] The main body portion of the high-pressure gas storage tank of the present application can be composed of only the aforementioned gasket for a pressure vessel, or can have the gasket for a pressure vessel and an outer layer for reinforcing the gasket. The gasket of the present application has excellent pressure resistance and impact resistance, and thus, in the case where the outer layer is further provided, the thickness thereof can be reduced.

[0168] The high-pressure gas storage tank having the gasket of the present application and the outer layer will be described below. Figure 5

[0169] Figure 5 is a cross-sectional schematic view showing one embodiment of the high-pressure gas storage tank of the present application, and the high-pressure gas storage tank 200 has a gasket 100' and an outer layer 4. The outer layer 4 is formed so as to cover the outer surface of the gasket 100' without a gap.

[0170] The outer layer 4 is not particularly limited as long as it can reinforce the gasket 100'.

[0171] ​The outer layer 4 is preferably made of a fiber-reinforced composite material from the viewpoint of barrier properties against gases such as hydrogen and impact resistance. The same material as that of the fiber-reinforced composite material constituting the gasket 100' can be used as the fiber-reinforced composite material constituting the outer layer 4.

[0172] The thickness of the outer layer can be appropriately selected depending on the capacity, shape, and the like of the high-pressure gas tank, and is preferably 100 μm or greater, more preferably 200 μm or greater, and further preferably 400 μm or greater from the viewpoint of imparting high gas barrier properties and impact resistance, and is preferably 80 mm or less, and more preferably 60 mm or less from the viewpoint of miniaturization and weight reduction of the high-pressure gas tank.

[0173] The outer layer 4 can be directly provided to the outer surface of the gasket 100'. Alternatively, one or more other layers can be provided to the outer surface of the gasket, and the outer layer 4 can be provided to the surface of the other layer. For example, an adhesive layer can be provided between the gasket and the outer layer in order to improve adhesion between the gasket and the outer layer.

[0174] In addition, any layer such as a protective layer, a paint layer, a layer containing a rust preventive, and the like can be formed on the surface of the outer layer 4.

[0175] The pipe head 5 is, for example, a substantially cylindrical shape, is inserted between the gasket 100' and the outer layer 4, and is fixed. The opening portion of the substantially cylindrical shape of the pipe head 5 functions as an opening portion of the high-pressure gas tank 200. The pipe head 5 can be formed of other metal such as stainless steel, aluminum, or the like, or can be formed of resin.

[0176] The boss 6 is formed of, for example, aluminum, is assembled in a state in which a part thereof is exposed to the outside, and functions to guide heat release and heat absorption inside the tank to the outside.

[0177] The valve 7 is, for example, a shape in which an external thread is formed in a cylindrical portion, and the opening portion of the pipe head 5 is closed by the valve 7 by screwing with an internal thread formed in the inner side surface of the pipe head 5. Note that in the high-pressure gas tank of the present application, the pipe head 5, the boss 6, and the valve 7 can be replaced by other means.

[0178] Note that the high-pressure gas tank in which the main body portion is made of only the gasket of the present application can be configured to be the same as the high-pressure gas tank shown in Figure 5 except that the outer layer 4 is provided. Alternatively, the pipe head 5 and the valve 7 can be attached to the opening portion 3 of the gasket 100 shown in Figure 1 and Figure 2 and used as a high-pressure gas tank.

[0179] Example

[0180] Next, the present application will be specifically described using examples. The present application is not at all limited to these examples.

[0181] The measurement and evaluation in the present embodiment were performed using the following method.

[0182] <Hydrogen permeation coefficient [cc 3 ·cm / (cm 2 ·s·cmHg)]

[0183] A cured product was produced using the epoxy resin composition produced in the production example, which was coated on a smooth metal plate on which a release agent had been applied to a thickness of 100 μm and a size of 200 mm square, and then heated at 100°C for 5 minutes to cure it. The cured product was used, and a hydrogen permeation coefficient was measured in a dry state at 23°C using a vapor permeation rate measuring device (G2700T·F manufactured by GTR TECH).

[0184] <Glass transition temperature>

[0185] The glass transition temperature Tg of the cured product of the epoxy resin composition used in the gasket produced in each of the examples was measured using a differential scanning calorimeter device (DSC25 manufactured by TA Instrument).

[0186] The sample (epoxy resin composition) was subjected to a thermal history of about 5 mg under the following conditions in a nitrogen atmosphere. The conditions of the thermal history were as follows: first temperature rise (temperature rise rate of 10°C / minute), followed by cooling (temperature drop rate of 10°C / minute), followed by second temperature rise (temperature rise rate of 10°C / minute). The heating temperature was set to room temperature to 225°C, and the peak temperature of the glass transition temperature observed at the second temperature rise was read and shown in Table 1.

[0187] <Tensile strength>

[0188] A 1A type test piece prescribed in JIS K7161-2:2014 was produced using a plate formed of the same material as the fiber-reinforced composite material constituting the gasket produced in each of the examples, and used for the measurement. A tensile test machine (AGX-100kNplus manufactured by Shimadzu Corporation) was used, and a tensile test was performed in accordance with JIS K7161-1:2014 and K7161-2:2014 under conditions of a temperature of 23°C, a distance between grips of 50 mm, and a test speed of 1 mm / minute, and the tensile strength was measured.

[0189] Production Example 1

[0190] (Preparation of epoxy resin curing agent solution A)

[0191] Into a reaction vessel, 1 mol of m-xylylenediamine (MXDA) was charged. While being warmed up to 60°C under a stream of nitrogen, 0.93 mol of methyl acrylate was added dropwise over a period of 1 hour. While distilling off the methyl alcohol produced, the temperature was raised to 165°C, and the temperature was maintained at 165°C for 2.5 hours, whereby a reaction product of MXDA and methyl acrylate, i.e., an epoxy resin curing agent was obtained. To this, methyl alcohol was added dropwise over a period of 1.5 hours, whereby an epoxy resin curing agent solution A was obtained, in which the aforementioned epoxy resin curing agent was 65 mass%, and methyl alcohol was 35 mass%.

[0192] (Preparation of Epoxy Resin Composition 1)

[0193] To 14.4 g of the epoxy resin curing agent solution A thus obtained, 1.5 g of methyl alcohol and 9.9 g of ethyl acetate were added as solvents, and 4.5 g of an epoxy resin having a glycidyl amino group derived from m-xylylenediamine ("TETRAD-X" manufactured by Mitsubishi Gas Chemical Company, Inc.) was added as an epoxy resin (active amine hydrogen amount in the epoxy resin curing agent / epoxy group amount in the epoxy resin = 1.2), and stirring was performed, whereby an epoxy resin composition 1 having a solid content concentration of 40 mass% was prepared.

[0194] Note that the hydrogen gas permeation coefficient of the cured product of the epoxy resin composition 1 was 3.9 x 10 -11 [cc 3 • cm / (cm 2 • s • cmHg)].

[0195] Example 1 (Production of a Liner for a Pressure Vessel and a High-Pressure Gas Storage Tank)

[0196] A liner for a pressure vessel and a high-pressure gas storage tank were produced according to the following protocol.

[0197] [Production of the Cylinder Part of the Liner]

[0198] As the thermosetting resin composition, the epoxy resin composition 1 obtained in Production Example 1 was used, and as the continuous reinforcing fiber, a continuous carbon fiber "Torayca Yarn T800SC-24000" (filament count: 24,000, fineness: 1,030 tex, tensile elastic modulus: 294 GPa) manufactured by Toray Industries, Inc. was used.

[0199] After impregnating the epoxy resin composition 1 into the continuous carbon fiber described above, the impregnated product was dried in a hot air drier at 80°C for 80 seconds, whereby a towpreg was produced. Subsequently, the towpreg was formed into a liner for a pressure vessel and a high-pressure gas storage tank by using a braiding method. Figure 3The braiding structure shown was braided on a metal mandrel having a diameter of 250 mm and a length of 1200 mm to produce a cylindrical prepreg having an outer diameter of 300 mm, a length of 1000 mm, and a thickness of 25 mm. After the cylindrical prepreg was cured by heating at 120°C for 30 minutes on the metal mandrel, the metal mandrel was removed to produce Figure 1 and Figure 2 The liner cylindrical portion 1 shown is made of a carbon fiber reinforced composite material. The volume fraction (Vf) of the continuous carbon fibers in the liner cylindrical portion 1 is 55%.

[0200] [Production of the dome portion of the liner]

[0201] As the thermosetting resin composition, the epoxy resin composition 1 obtained in Production Example 1 was used, and as the continuous reinforcing fiber, the continuous carbon fiber "Torayca Cloth UT70-30G" (unidirectional cloth, sheet thickness: 0.167 mm) manufactured by Toray Industries, Inc. was used.

[0202] After the epoxy resin composition 1 was impregnated into the continuous carbon fiber described above, it was dried by heating in a hot air drier at 80°C for 80 seconds to produce a prepreg. Next, a mold was used, and a dome portion 21 having an opening portion with a diameter of 50 mm and a dome portion 22 having no opening portion were produced by a hot press molding method under conditions of a pressurization pressure of 0.5 MPa, a pressurization temperature of 140°C, and a pressurization time of 120 minutes. Figure 1 and Figure 2 The dome portions 21 and 22 shown are hollow dome portions 21 having an opening portion with a diameter of 50 mm and a dome portion 22 having no opening portion. The dome portions 21 and 22 have an outer diameter of 300 mm, a dome height of 125 mm, a thickness of 25 mm, and a volume fraction (Vf) of the continuous carbon fibers of 55%.

[0203] [Production of the liner and the high-pressure gas storage tank]

[0204] The dome portions 21 and 22 were joined to both ends of the liner cylindrical portion 1 obtained by the aforementioned method by bolts, respectively, to obtain a liner 100 shown in Figure 1 and Figure 2 The liner 100 shown was obtained. Further, the same tow prepreg as that used in the production of the cylindrical portion of the liner was wound on the outer surface of the liner 100 by a filament winding method, and the liner 100 was heated at 120°C for 240 minutes to form an outer layer having a thickness of 60 mm, and a high-pressure gas storage tank was obtained.

[0205] Example 2 (Production of a liner for a pressure vessel and a high-pressure gas storage tank)

[0206] A tow prepreg was produced by the same method as in Example 1. Next, the tow prepreg was formed into a cylindrical portion of a liner by a plaiting method, and a dome portion of the liner was produced by a hot press molding method under conditions of a pressurization pressure of 0.5 MPa, a pressurization temperature of 140°C, and a pressurization time of 120 minutes. Figure 3The braiding structure shown was braided on a metal mandrel having a diameter of 250 mm and a length of 1200 mm to produce a prepreg having a shape in which the end of a cylindrical portion was sealed by a dome portion. The prepreg cylindrical portion had an outer diameter of 300 mm, a length of 1000 mm, and a thickness of 25 mm, and the prepreg dome portion had an outer diameter of 300 mm, a dome height of 125 mm, and a thickness of 25 mm. After the prepreg was heat-cured on the metal mandrel at 120°C for 30 minutes, the metal mandrel was removed to produce a member in which the end of the gasket cylindrical portion 1 was sealed by the dome portion 22. The volume fraction (Vf) of the continuous carbon fibers in the member was 55%.

[0207] Next, a hollow dome portion 21 having an outer diameter of 300 mm, a dome height of 125 mm, and a thickness of 25 mm and an opening portion having a diameter of 50 mm was produced by the same method as in Example 1, and was joined to the aforementioned member by bolting to obtain a gasket 100. Further, an outer layer was formed on the outer surface of the gasket 100 by the same operation as in Example 1 to obtain a high-pressure gas tank.

[0208] In addition, the glass transition temperature of the epoxy resin cured product and the tensile strength of the fiber-reinforced composite material constituting the gasket cylindrical portion obtained in Example 1 and Example 2 were measured by the aforementioned method, and the results are shown in Table 1.

[0209] Note that, in Table 1, instead of the fiber-reinforced composite material used in Example 1 and Example 2, a polyethylene resin ("UF420" manufactured by Japan Polyethylene Corporation) was used as a thermoplastic resin, and the glass transition temperature and the tensile strength of the polyethylene resin were measured by the aforementioned method, and the results are shown together (Reference Example 1).

[0210] [Table 1]

[0211] Table 1

[0212] Example 1 Example 2 Reference Example 1 Glass transition temperature (°C) 65 65 -125 Tensile strength (MPa) 850 850 30

[0213] Industrial Applicability

[0214] According to the present application, a gasket for pressure vessels having light weight, gas barrier properties for hydrogen and the like, heat resistance, and high strength, and also excellent productivity can be provided.

[0215] The gasket for pressure vessels of the present application has high gas barrier properties, heat resistance, and strength, and thus can be used directly as a pressure vessel such as a high-pressure gas tank without providing an outer layer. A high-pressure gas tank provided with the gasket for pressure vessels is suitable as a high-pressure gas tank for vehicles, and is light in weight, and thus can improve the fuel consumption of a vehicle.

[0216] Explanation of Reference Numerals

[0217] 100, 100' liner for pressure vessel

[0218] 1 cylindrical portion

[0219] 1a, 1b end portion of cylindrical portion

[0220] 21, 22 dome portion

[0221] 3 opening portion

[0222] 10 fiber-reinforced composite material

[0223] 11 cured product of towpreg

[0224] 200 high-pressure gas tank

[0225] 4 outer layer

[0226] 5 pipe head

[0227] 6 protrusion

[0228] 7 valve

Claims

1. A high-pressure gas storage tank comprising a pressure vessel liner, the pressure vessel liner being made of a fiber-reinforced composite material, the fiber-reinforced composite material comprising a cured thermosetting resin composition and comprising continuous reinforcing fibers. The thermosetting resin composition is an epoxy resin composition containing epoxy resin (A) and epoxy resin curing agent (B), wherein the epoxy resin curing agent (B) comprises the reaction product (X) of the following components (x1) and components (x2). The high-pressure gas in the high-pressure gas storage tank is hydrogen. (x1) Select at least one from the group consisting of m-phenylenediamine and p-phenylenediamine; (x2) Select at least one from the group consisting of unsaturated carboxylic acids and their derivatives represented by the general formula (1) below. In equation (1), R 1 R 2 Each can independently represent a hydrogen atom, an alkyl group with 1 to 8 carbon atoms, an aryl group with 6 to 12 carbon atoms, or an aralkyl group with 7 to 13 carbon atoms.

2. The high-pressure gas storage tank according to claim 1, wherein, The fiber-reinforced composite material constituting the liner has a braided or spiral structure.

3. The high-pressure gas storage tank according to claim 1 or 2, wherein, The gasket has a cylindrical portion and two rounded tops that seal both ends of the cylindrical portion.

4. The high-pressure gas storage tank according to claim 3, wherein, The cylindrical portion is integrally formed with at least one of the dome portions.

5. The high-pressure gas storage tank according to claim 1 or 2, wherein, The epoxy resin (A) uses an epoxy resin with glycidyl amino groups derived from m-phenylenediamine as the main component.

6. The high-pressure gas storage tank according to claim 1 or 2, wherein, The continuous reinforcing fiber is selected from at least one of the group consisting of glass fiber, carbon fiber and basalt fiber.

7. The high-pressure gas storage tank according to claim 1 or 2, wherein, The method for manufacturing the gasket for the pressure vessel includes the following steps: The prepreg made of the thermosetting resin composition and continuous reinforcing fiber bundles is formed using a yarn-adding method or a yarn-winding method.

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