Rubber composition for rubber layer used in hydrogen-transfer laminated hose, and hydrogen-transfer laminated hose

Abstract

Provided is a hydrogen-transfer laminated hose excellent in interlayer adhesion and hydrogen gas seal. Further, for example, a hydrogen-transfer laminated hose that exhibits good handling properties when used while connected to a dispenser installed at a hydrogen station is provided.　A rubber composition for a rubber layer used in the hydrogen-transfer laminated hose contains the following components (A) to (E). (A) an ethylene / α -olefin / non-conjugated diene copolymer, (B) a petroleum resin-based tackifier containing a structural unit derived from aromatic monomers, (C) a phenol resin-based tackifier, (D) a bismaleimide compound, and (E) a crosslinking agent.

Description

Rubber composition for rubber layer used in a rubber layer of a laminated hose for hydrogen transfer, and laminated hose for hydrogen transfer

[0001] The present invention relates to a rubber composition for a rubber layer used in a rubber layer of a laminated hose for hydrogen transfer. Specifically, the present invention relates to a rubber composition for a rubber layer used in a rubber layer of a laminated hose for hydrogen transfer that is used, for example, for filling hydrogen gas into a tank of a fuel cell vehicle or the like from a dispenser installed in a hydrogen station.

[0002] In recent years, research and development of fuel cell vehicles and the like have been progressing. Along with this, development of hoses for filling hydrogen gas into tanks of fuel cell vehicles and the like from dispensers installed in hydrogen stations has been actively carried out. For example, from the viewpoint of improving hydrogen gas permeation resistance, a hose is proposed which is formed by laminating an inner surface layer made of a resin such as polyamide or ethylene-vinyl alcohol copolymer having a specific hydrogen gas permeability coefficient, an outer layer made of a thermoplastic resin such as polyamide or polyester, and a reinforcing layer having a spiral structure or a braided structure formed by braiding metal wires or organic fibers.

[0003] Japanese Unexamined Patent Publication No. 2010-031993

[0004] Conventional laminated hoses for hydrogen transfer are mainly molded using resin materials such as polyester, resulting in high bending rigidity and posing challenges in handling when connected to dispensers installed at hydrogen stations. Furthermore, conventional laminated hoses for hydrogen transfer with high bending rigidity are prone to kinking during use, raising concerns about hose damage due to localized stress accumulation and, consequently, hydrogen gas leakage. In view of these circumstances, the inventors conceived of a laminated hose for hydrogen transfer that includes a laminated structure in which a rubber layer is formed on the outer surface of a resin layer with excellent hydrogen gas barrier properties, with the aim of increasing the flexibility of the laminated hose for hydrogen transfer and improving handling and durability during use, and have diligently conducted research on it. However, in order to efficiently transfer hydrogen gas at high pressure, it is necessary to pre-cool the hydrogen gas, and in this process, the hydrogen gas is cooled to approximately -40°C to -35°C. Therefore, laminated hoses for hydrogen transfer are required to have the durability to repeatedly withstand the internal pressure of high-pressure, low-temperature hydrogen gas. However, our investigations have revealed that laminated structures with a rubber layer formed on the outer surface of a resin layer have problems with interlayer adhesion, and further research is needed.

[0005] This invention has been made in view of these circumstances, and provides a durable laminated hydrogen transfer hose by improving the interlayer adhesion in a laminated hydrogen transfer hose that includes a laminated structure consisting of a rubber layer and a resin layer.

[0006] Furthermore, in one embodiment of the present invention, a laminated hydrogen transfer hose is provided that exhibits excellent durability, good flexibility even in low-temperature environments, and excellent handling when used, for example, connected to a dispenser installed at a hydrogen station.

[0007] The inventors diligently conducted research to solve the above problems. In the course of this research, from the viewpoint of achieving interlayer adhesion that can withstand use under high pressure and low temperature conditions, they found that by using a specific tackifier in combination with a specific rubber component in the rubber composition constituting the rubber layer of a laminated hydrogen transfer hose, and further by using a bismaleimide compound in combination, a laminated hydrogen transfer hose with excellent interlayer adhesion can be obtained. In other words, the inventors considered incorporating various tackifiers, but it was difficult to sufficiently improve the interlayer adhesion by simply incorporating various tackifiers into the rubber composition for the rubber layer. The inventors, in addition to examining the types of tackifiers, diligently conducted further research focusing on the affinity between the rubber component and other compounding components, as well as the interactions between each compounding component. As a result, they discovered that by using an ethylene-α-olefin-non-conjugated diene copolymer among various types of rubbers, and by using a rubber composition for the rubber layer that combines petroleum resin-based tackifiers and phenol resin-based tackifiers among various compounding agents, and further incorporating a bismaleimide compound, the interlayer adhesion to the resin layer containing polyamide and the like is significantly improved, making it possible to provide a laminated hose for hydrogen transfer with excellent durability and, consequently, hydrogen gas sealing properties, thus arriving at the present invention.

[0008] In other words, the gist of the present invention is as follows: [1] A rubber composition for a rubber layer used in the rubber layer of a laminated hose for hydrogen transfer, comprising the following components (A) to (E): (A) Ethylene-α-olefin-non-conjugated diene copolymer (B) Petroleum resin-based tackifier containing constituent units derived from aromatic monomers (C) Phenolic resin-based tackifier (D) Bismaleimide compound (E) Crosslinking agent [2] The rubber composition for a rubber layer according to [1], wherein the mass ratio (B / C) of component (B) to component (C) is 0.4 to 2.5. [3] The rubber composition for a rubber layer according to [1] or [2], wherein the total content (B+C) of component (B) and component (C) is 5 to 20 parts by mass per 100 parts by mass of component (A). [4] The rubber composition for a rubber layer according to any one of [1] to [3], wherein component (C) is an alkylphenol resin. [5] The rubber composition for a rubber layer according to any one of [1] to [4], wherein the component (C) is an alkylphenol acetaldehyde resin. [6] The rubber composition for a rubber layer according to any one of [1] to [5], further containing carbon black. [7] The rubber composition for a rubber layer according to any one of [1] to [6], further containing poly-α-olefin oil. [8] The rubber composition for a rubber layer according to any one of [1] to [7], wherein the content of the component (D) is 2 parts by mass or more per 100 parts by mass of the component (A). [9] The rubber composition for a rubber layer according to any one of [1] to [8], wherein the crosslinking agent (E) is a sulfur-based crosslinking agent and a peroxide-based crosslinking agent.

[10] A laminated hose for hydrogen transfer, comprising a laminated structure in which a resin layer containing at least one of a polyamide and an ethylene-vinyl alcohol copolymer is laminated on the outer surface of the resin layer, wherein the rubber layer is a rubber layer made of a crosslinked product of the rubber composition for a rubber layer according to any one of [1] to [9].

[0009] According to the present invention, it is possible to improve the interlayer adhesion in a laminated hydrogen transfer hose including a laminated structure consisting of a rubber layer and a resin layer, and to provide a durable laminated hydrogen transfer hose.

[0010] According to one embodiment of the present invention, the laminated hose for hydrogen transfer exhibits excellent durability and good flexibility even in low-temperature environments, and is easy to handle when used, for example, when connected to a dispenser installed at a hydrogen station.

[0011] This is a schematic perspective view showing an example of a hose according to one embodiment of the present invention.

[0012] Next, embodiments of the present invention will be described in detail. In this specification, "main component" means a component that has a significant effect on the properties of the material, and unless otherwise specified, the content of the component is 50% by mass or more of the total material, preferably 60-100% by mass, 70-100% by mass, 80-100% by mass, 90-100% by mass, etc. Also, in this specification, "X and / or Y (X, Y are any configuration)" means at least one of X and Y, and has three meanings: X only, Y only, or X and Y. Furthermore, in the numerical ranges described in steps in this specification, the upper or lower limit of a numerical range in one step can be arbitrarily combined with the upper or lower limit of a numerical range in another step. Also, in the numerical ranges described in this specification, the upper or lower limit of a numerical range can be replaced with the values ​​shown in the examples. Furthermore, in this specification, "(meth)acrylic" means acrylic and / or methacrylic, "(meth)acryloyl" means acryloyl and / or methacryloyl, and "(meth)acrylate" means acrylate and / or methacrylate.

[0013] <<Rubber Composition for Rubber Layers Used in Laminated Hydrogen Transfer Hoses>> The rubber composition for rubber layers used in laminated hydrogen transfer hoses of the present invention (hereinafter sometimes referred to as "this rubber composition") is characterized by containing components (A) to (E). (A) Ethylene-α-olefin-non-conjugated diene copolymer (B) Petroleum resin-based tackifier containing constituent units derived from aromatic monomers (C) Phenolic resin-based tackifier (D) Bismaleimide compound (E) Crosslinking agent

[0014] The reason why high interlayer adhesion can be obtained in a laminated hydrogen transfer hose using this rubber composition as the rubber layer is not entirely clear, but it is presumed that by combining (B) a petroleum resin-based tackifier containing constituent units derived from aromatic monomers, (C) a phenol resin-based tackifier, and (D) a bismaleimide compound, the affinity for (A) ethylene-α-olefin-non-conjugated diene copolymer is reduced, and migration to the rubber layer surface is promoted, resulting in the formation of a diffusion layer, strengthening interlayer unification, and increasing interlayer adhesion. Specifically, for example, in a laminated hose including a laminated structure in which a rubber layer using this rubber composition and a resin layer are laminated, it is presumed that components (B) to (D) are attracted and mixed by interaction and their migration to the interface is promoted, and further, the migration of component (E) to the interface also combines to form a strong crosslinked structure, strengthening interlayer unification and increasing interlayer adhesion. Embodiments of the present invention will be described in more detail below.

[0015] [(A) Ethylene-α-olefin-non-conjugated diene copolymer] Ethylene-α-olefin-non-conjugated diene copolymer is a copolymer having ethylene, α-olefin, and a non-conjugated diene compound as copolymer components. Component (A) may be used alone, or two or more components with different types of constituent units, compositions, and physical properties may be used.

[0016] Examples of α-olefins in component (A) include propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, 1-octene, 1-decene, and 1-octadecene, which have 3 to 20 carbon atoms. These can be used alone or in combination of two or more. Among these, propylene, 1-butene, 3-methyl-1-butene, and 1-pentene are preferred, and propylene is more preferred.

[0017] Examples of non-conjugated diene compounds in component (A) include dicyclopentadiene, 1,4-hexadiene, cyclohexadiene, cyclooctadiene, dicyclooctadiene, 1,6-octadiene, 5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene, 1,3-cyclopentadiene, 1,4-cyclohexadiene, 2-methyl-1,5-hexadiene, and 6-methyl Examples include -1,5-heptadiene, 7-methyl-1,6-octadiene, tetrahydroindene, methyltetrahydroindene, 5-isopropylidene-2-norbornene, 5-vinyl-2-norbornene, vinylidenenorbornene, ethylidenenorbornene such as 5-ethylidene-2-norbornene (ENB), and methylenenorbornene such as 5-methylene-2-norbornene (MNB). These can be used individually or in combination of two or more. Among these, ethylidenenorbornene is preferred.

[0018] (A) Suitable specific examples of component include, for example, ethylene-propylene-non-conjugated diene copolymer rubber (EPDM), ethylene-butene-non-conjugated diene copolymer rubber (EBT), and ethylene-propylene-butene-non-conjugated diene copolymer (EPBDM). These can be used alone or in combination of two or more.

[0019] The ethylene content of component (A) is not particularly limited, but from the viewpoint of significantly exhibiting the effects of the present invention, it is preferably 48 to 70% by mass, and more preferably 50 to 60% by mass. The α-olefin content of component (A) is not particularly limited, but from the viewpoint of significantly exhibiting the effects of the present invention, it is preferably 22 to 46% by mass, and more preferably 30 to 44% by mass. The non-conjugated diene content of component (A) is not particularly limited, but from the viewpoint of significantly exhibiting the effects of the present invention, it is preferably 3 to 11% by mass, and more preferably 3.5 to 6% by mass.

[0020] (A) Mooney viscosity of component (ML １＋４ The temperature (125°C) is not particularly limited, but from the viewpoint of significantly exhibiting the effects of the present invention, it is preferably 20 to 90, more preferably 30 to 88, and even more preferably 40 to 85.

[0021] The content of component (A) is not particularly limited, but is usually 25% by mass or more, preferably 30 to 60% by mass, and more preferably 34 to 50% by mass, relative to the rubber composition (100% by mass). Furthermore, component (A) is the main component of the rubber components contained in the rubber composition, and is preferably 70% by mass or more, relative to the total amount of rubber components contained in the rubber composition (100% by mass), for example, 70 to 100% by mass, 80 to 100% by mass, 90 to 100% by mass, 95 to 100% by mass, etc.

[0022] [(B) Petroleum resin-based tackifiers containing constituent units derived from aromatic monomers] Examples of component (B) include aromatic (C9) petroleum resins, aliphatic / aromatic copolymer (C5 / C9) petroleum resins, hydrogenated versions thereof (partially water-added petroleum resins, fully water-added petroleum resins), and various modified versions thereof (e.g., maleic anhydride modified versions). These may be used alone or in combination of two or more. Aromatic (C9) petroleum resins are petroleum resins polymerized using the C9 fraction of petroleum as a raw material, and aliphatic / aromatic copolymer (C5 / C9) petroleum resins are petroleum resins polymerized using the C5 and C9 fractions of petroleum as raw materials. Examples of the C9 fraction include styrene, vinyltoluene, and indene. Examples of the C5 fraction include cyclopentadiene, isoprene, and pentane.

[0023] The aromatic (C9) petroleum resin is not particularly limited, but is preferably an aromatic (C9) petroleum resin consisting of one or more constituent units selected from the group consisting of indene, styrene, and vinyltoluene, and more preferably an aromatic (C9) petroleum resin consisting of two or three constituent units selected from the group consisting of indene, styrene, and vinyltoluene. The aliphatic / aromatic copolymer (C5 / C9) petroleum resin is not particularly limited, but is preferably an aliphatic / aromatic copolymer (C5 / C9) petroleum resin consisting of one or more constituent units selected from the group consisting of indene, styrene, and vinyltoluene, and constituent units derived from isoprene and / or piperine.

[0024] As for component (B), from the viewpoint of further improving the interlayer adhesion between the rubber layer and the resin layer, a petroleum resin-based tackifier is preferred in which the content of constituent units derived from aromatic monomers is 20% by mass or more relative to the total constituent units of component (B). From a similar viewpoint, the content of constituent units derived from aromatic monomers is more preferably 25% by mass or more, even more preferably 30% by mass or more, particularly preferably 35% by mass or more, and especially preferably 40% by mass or more. Furthermore, the content of constituent units derived from aromatic monomers relative to the total constituent units of component (B) can be appropriately set within the above range, for example, 60 to 100% by mass is preferred.

[0025] Furthermore, if component (B) includes constituent units derived from aliphatic monomers, the content thereof is, for example, 80% by mass or less, preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 50% by mass or less, and particularly preferably 40% by mass or less, relative to the total constituent units of component (B).

[0026] The softening point of component (B) is not particularly limited, but is preferably 50 to 200°C, more preferably 60 to 150°C, and even more preferably 70 to 120°C. The softening point is measured by the ring-and-ball method in accordance with JIS K2207.

[0027] The content of component (B) is not particularly limited, but from the viewpoint of further improving the interlayer adhesion between the rubber layer and the resin layer, it is preferably 2.5 to 14 parts by mass, more preferably 2.8 to 12 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of component (A). Furthermore, the content of component (B) can be appropriately set within the above range, for example, it may be 4 to 8 parts by mass, 4 to 6 parts by mass, etc.

[0028] [(C) Phenolic resin-based tackifier] Examples of component (C) include condensates of phenols and aldehydes, resol-type phenolic resins, novolac-type phenolic resins, and rosin-modified phenolic resins. These can be used alone or in combination of two or more. Among these, condensates of phenols and aldehydes are preferred from the viewpoint of further improving the interlayer adhesion between the rubber layer and the resin layer, and examples of condensates of phenols and aldehydes include alkylphenol resins.

[0029] Alkylphenol resins are condensates of alkylphenol components and aldehydes. Examples of alkylphenol components include phenols having alkyl groups with 1 to 18 carbon atoms, such as cresol, isopropylphenol, t-butylphenol, amylphenol, octylphenol (e.g., p-octylphenol), nonylphenol, dodecylphenol, allylphenol, and cyclohexylphenol, as well as various derivatives such as methylolated and halogenated derivatives of these compounds.

[0030] Examples of the above-mentioned aldehydes include formaldehyde, paraformaldehyde, trioxane, polyoxymethylene, acetaldehyde, propionaldehyde, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allylaldehyde, benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde, and paraxylenedimethyl ether.

[0031] Suitable examples of alkylphenol resins include alkylphenol acetylene resins, alkylphenol formaldehyde resins, alkylphenol acetaldehyde resins, and the like.

[0032] The softening point of component (C) is not particularly limited, but is preferably 50 to 200°C, more preferably 60 to 150°C, and even more preferably 70 to 120°C. The softening point is measured by the ring-and-ball method in accordance with JIS K2207.

[0033] The content of component (C) is not particularly limited, but from the viewpoint of further improving the interlayer adhesion between the rubber layer and the resin layer, it is preferably 2.5 to 14 parts by mass, more preferably 2.8 to 12 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of component (A). Furthermore, the content of component (C) can be appropriately set within the above range, for example, it may be 4 to 8 parts by mass, 4 to 6 parts by mass, etc.

[0034] Examples of commercially available components of (C) include Tackiroll® 201 (alkylphenol formaldehyde resin, manufactured by Taoka Chemical Co., Ltd.), Tackiroll® 250-I (brominated alkylphenol formaldehyde resin, manufactured by Taoka Chemical Co., Ltd.), Tackiroll® 250-III (brominated alkylphenol formaldehyde resin, manufactured by Taoka Chemical Co., Ltd.), Schenectady SP1059, Schenectady SP1045, Schenectady SP-1055, Schenectady SP-1056 (manufactured by Schenectady Chem Co., Ltd.).

[0035] The mass ratio (B / C) of component (B) to component (C) is not particularly limited, but from the viewpoint of further improving the interlayer adhesion between the rubber layer and the resin layer, it is preferably 0.4 to 2.5, and more preferably 0.4 to 2.4. Furthermore, the above mass ratio (B / C) can be appropriately set within the above range, for example, it may be 0.5 to 1.5, 0.8 to 1.2, etc.

[0036] The total content of component (C) and component (B) (B+C) is not particularly limited, but from the viewpoint of further improving the interlayer adhesion between the rubber layer and the resin layer, it is, for example, 5 to 20 parts by mass, preferably 5 to 18 parts by mass, and more preferably 6 to 15 parts by mass, per 100 parts by mass of component (A). The above total content (B+C) can be set appropriately within the above range and is not particularly limited, but for example, it may be 8 to 12 parts by mass.

[0037] [(D) Bismaleimide Compounds] Component (D) is a compound having two maleimide groups in its molecule, and examples include aromatic bismaleimides and aliphatic bismaleimides. These can be used alone or in combination of two or more.

[0038] Aromatic bismaleimide compounds are compounds comprising a bismaleimide structure and a structure having an aromatic ring. Examples of structures having an aromatic ring include aryl groups and arylene groups having 6 to 30 carbon atoms. The aryl groups and arylene groups may have substituents. Examples of structures having an aromatic ring include phenylene groups, methylphenylene groups, ethylphenylene groups, propylphenylene groups, butylphenylene groups, dimethylphenylene groups, diethylphenylene groups, dipropylphenylene groups, trimethylphenylene groups, tetramethylphenylene groups, dibutylphenylene groups, naphthylene groups, biphenylene groups, fluorenylene groups, phenantrenylene groups, and anthraquinolylene groups. Among these, phenylene groups are preferred.

[0039] Specific examples of aromatic bismaleimide compounds include, for example, N,N'-(1,3-phenylene)bismaleimide, N,N'-(4-methyl-1,3-phenylene)bismaleimide, N,N'-(1,4-phenylene)bismaleimide, N,N'-(1,2-phenylene)bismaleimide, N,N'-(1,5-naphthylene)bismaleimide, N,N'-(4-chloro-1,3-phenylene)bismaleimide, and N,N'-(methylenedi-p-phenylene) N,N'-(4,4'-biphenylene)bismaleimide, N,N'-(sulfonyldi-p-phenylene)bismaleimide, N,N'-(oxydi-p-phenylene)bismaleimide, N,N'-(3,3'-dimethyl-4,4'-biphenylene)bismaleimide, N,N'-(benzylidenedi-p-phenylene)bismaleimide, N,N'-[methylenebis(3-chloro-4-phenylene)]bismaleimide, N,N'-[meth Lenbis(3-methyl-4-phenylene)]bismaleimide, N,N'-[methylenebis(3-methoxy-4-phenylene)]bismaleimide, N,N'-(thiodi-p-phenylene)bismaleimide, N,N'-3,3'-benzophenonebismaleimide, N,N'-[methylenebis(3-methyl-5-ethyl-4-phenylene)]bismaleimide, N,N'-[tetramethylenebis(oxy-p-phenylene)]bismaleimide, 2,2-bis Examples include [4-(4-maleimidophenoxy)phenyl]propane, bis[4-(4-maleimidophenoxy)phenyl]sulfone, 1,4-phenylenebis(4-maleimidophenoxy), bis[3-(4-maleimidophenoxy)phenyl]sulfone, bis[4-(3-maleimidophenoxy)phenyl]ketone, 1,3-phenylenebis(4-maleimidophenoxy), and bis[4-(4-maleimidophenylthio)phenyl]ether. Among these, N,N'-(1,3-phenylene)bismaleimide is preferred.

[0040] Examples of the aliphatic bismaleimide compound include N,N'-(2,2,4-trimethylhexamethylene)bismaleimide, N,N'-decamethylene bismaleimide, N,N'-octamethylene bismaleimide, N,N'-heptamethylene bismaleimide, N,N'-hexamethylene bismaleimide, N,N'-pentamethylene bismaleimide, N,N'-tetramethylene bismaleimide, N,N'-trimethylene bismaleimide, N,N'-ethylene bismaleimide, N,N'-(oxydimethylene)bismaleimide, 1,13-bismaleimide-4,7,10-trioxatridecane, 1,11-bismaleimide-3,6,9-trioxaundecane, and the like.

[0041] Among these components (D), aromatic bismaleimide compounds are preferred from the viewpoint of further improving interlayer adhesion between the rubber layer and the resin layer. It is presumed that by using an aromatic bismaleimide compound as component (D), the affinity for component (A) decreases, migration to the interface is further promoted, and as a result, higher interlayer adhesion can be obtained.

[0042] The content of component (D) is not particularly limited, but from the viewpoint of further improving interlayer adhesion between the rubber layer and the resin layer, it is preferably 1.5 parts by mass or more, more preferably 2 parts by mass or more, relative to 100 parts by mass of component (A). The content of component (D) can be appropriately set within the above range, and is not particularly limited, and may be, for example, 2 to 12 parts by mass, 2 to 10 parts by mass, 2 to 8 parts by mass, etc.

[0043] [(E) Crosslinking agent] Examples of component (E) include sulfur-based crosslinking agents and peroxide-based crosslinking agents. These may be used alone or in combination of two or more kinds.

[0044] Examples of the sulfur-based crosslinking agent include powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur, and the like.

[0045] Examples of peroxide-based crosslinking agents include 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, n-butyl-4,4′-di-t-butylperoxyvalerate, dicumyl peroxide, t-butylperoxybenzoate, di-t-butylperoxydiisopropylbenzene, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexyn-3, and 1,3-bis-(t-butylperoxyisopropyl)benzene.

[0046] From the viewpoint of significantly achieving the effects of the present invention, the content of component (E) is preferably 0.2 to 12 parts by mass, more preferably 0.3 to 10 parts by mass, and even more preferably 0.4 to 8 parts by mass, per 100 parts by mass of component (A).

[0047] When a sulfur-based crosslinking agent is used as component (E), the content of the sulfur-based crosslinking agent is preferably 0.2 to 10 parts by mass, more preferably 0.3 to 4 parts by mass, and even more preferably 0.4 to 3 parts by mass, per 100 parts by mass of component (A), from the viewpoint of significantly exhibiting the effects of the present invention.

[0048] When a peroxide-based crosslinking agent is used as component (E), the content of the peroxide-based crosslinking agent is preferably 0.5 to 12 parts by mass, more preferably 1 to 8 parts by mass, even more preferably 2 to 5 parts by mass, and particularly preferably 2.5 to 4 parts by mass, per 100 parts by mass of component (A), from the viewpoint of significantly exhibiting the effects of the present invention.

[0049] In one example of the embodiments of this rubber composition, it is preferable to include both a sulfur-based crosslinking agent and a peroxide-based crosslinking agent from the viewpoint of significantly exhibiting the effects of the present invention. When a sulfur-based crosslinking agent and a peroxide-based crosslinking agent are used as component (E), the total content of both is preferably 0.5 to 12 parts by mass, more preferably 1 to 8 parts by mass, even more preferably 1.2 to 6 parts by mass, and particularly preferably 1.5 to 4 parts by mass, per 100 parts by mass of component (A), from the viewpoint of significantly exhibiting the effects of the present invention.

[0050] (Plasticizer) In one example of the embodiments of this rubber composition, it is preferable to use a plasticizer in addition to the components (A) to (E) above. Examples of plasticizers include mineral oils and synthetic oils. Examples of mineral oils include paraffinic, naphthenic, and aromatic mineral oils. Examples of synthetic oils include poly-αolefin, trimellitic acid derivatives, polyester derivatives, and phthalic acid derivatives. Among these, paraffinic oil and poly-αolefin oil are particularly preferred. When paraffinic oil is used, there is a tendency for a good balance between interlayer adhesion and low-temperature flexibility, and when poly-αolefin oil is used, there is a tendency for good low-temperature flexibility.

[0051] The content of the plasticizer is not particularly limited, but is preferably 3 to 25 parts by mass, and more preferably 8 to 15 parts by mass, per 100 parts by mass of component (A).

[0052] (Softener) In one embodiment of this rubber composition, it is preferable to use a softener in addition to the above components (A) to (E) from the viewpoint of improving the handling properties during processing. Any conventionally known softener can be used as appropriate, and is not particularly limited, but polybutene and the like are suitable examples.

[0053] The kinematic viscosity (at 100°C) of the softener is not particularly limited, but for example, 3 to 6000 mm. ２ / s, 100-5000 mm ２ / s is preferred, and more preferably 600 to 4000 mm ２ The value is / s. The kinematic viscosity is a value measured in accordance with JIS K2283 (100°C), and may also be a value obtained from the raw material manufacturer's catalog.

[0054] The number-average molecular weight (Mn) of the softening agent is not particularly limited, but is, for example, 200 to 5000, preferably 800 to 4500, and more preferably 1500 to 3500. The number-average molecular weight is a value measured using GPC, or it may be a value obtained from the raw material manufacturer's catalog.

[0055] The amount of softening agent is not particularly limited, but from the viewpoint of improving the handling properties when kneading during processing, it is preferably 3 to 25 parts by mass, and more preferably 8 to 15 parts by mass, per 100 parts by mass of component (A).

[0056] (Carbon Black) In one example of the embodiments of this rubber composition, it is preferable to use carbon black in addition to the above components (A) to (E) in order to further improve the interlayer adhesion between the rubber layer and the resin layer and to improve the mechanical strength of the laminated hose for hydrogen transfer.

[0057] While there are no particular limitations on the type of carbon black used, various grades of carbon black can be used, such as SAF, ISAF, HAF, MAF, FEF, GPF, SRF, FT, and MT. Among these, FEF grade is preferred.

[0058] The specific surface area for nitrogen adsorption of carbon black is not particularly limited, but for example, it is 20 to 150 m². 2 A value of / g is preferred, and more preferably 20 to 80 m 2 / g, more preferably 40 to 80m 2 The specific surface area for nitrogen adsorption of carbon black can be measured according to the method described in JIS K6217-2.

[0059] The carbon black content is not particularly limited, but is preferably 50 to 180 parts by mass, more preferably 60 to 160 parts by mass, and even more preferably 80 to 140 parts by mass, per 100 parts by mass of component (A).

[0060] [Other Components] In addition to the components (A) to (E) described above, this rubber composition may contain, without particular limitation, other components used in rubber compositions, such as crosslinking accelerators, co-crosslinking agents, fillers, crosslinking aids, etc., as needed. These may be used individually or in combination of two or more.

[0061] The crosslinking accelerator is not particularly limited, but examples include thiram-based crosslinking accelerators such as tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), tetrakis(2-ethylhexyl)thiuram disulfide (TOT), and tetrabenzylthiuram disulfide (TBzTD); N-oxydiethylene-2-benzothiazolyl sulfenamide (NOBS), N-cyclohexyl-2-benzothiazolyl sulfenamide (CBS), and N-t-butyl Examples include sulfenamide-based crosslinking accelerators such as 2-benzothiazolyl sulfenamide (BBS) and N,N'-dicyclohexyl-2-benzothiazolyl sulfenamide; thiazole-based crosslinking accelerators such as dibenzothiadyl disulfide (MBTS), 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole sodium salt (NaMBT), and 2-mercaptobenzothiazole zinc salt (ZnMBT); dithioate-based crosslinking accelerators such as dibutyldithiocarbamate zinc (ZnBDC); and sulfur chloride and sulfur disulfide.

[0062] The amount of crosslinking accelerator is not particularly limited, but is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of component (A). The total amount of sulfur-based crosslinking agent and crosslinking accelerator is, for example, preferably 1 to 8 parts by mass, more preferably 2 to 6 parts by mass, and even more preferably 3 to 5 parts by mass, per 100 parts by mass of component (A).

[0063] The co-crosslinking agent is not particularly limited, but examples include (meth)acrylic monomers, (meth)acrylic oligomers, and (meth)acrylic modified polymers. The content of the co-crosslinking agent is not particularly limited, but is preferably 1 to 8 parts by mass, and more preferably 1.5 to 6 parts by mass, per 100 parts by mass of component (A). The co-crosslinking agent is usually used together with a peroxide-based crosslinking agent, and the total content of the peroxide-based crosslinking agent and the co-crosslinking agent is not particularly limited, but is preferably 1 to 18 parts by mass, and more preferably 3 to 8 parts by mass, per 100 parts by mass of component (A).

[0064] The filler is not particularly limited, but examples include talc, mica, clay, calcium carbonate, etc. The content of the filler (excluding carbon black) is not particularly limited, but is preferably 50 to 140 parts by mass, more preferably 60 to 120 parts by mass, and even more preferably 80 to 100 parts by mass, per 100 parts by mass of component (A).

[0065] The crosslinking aid is not particularly limited, but examples include zinc oxide, zinc oxide (ZnO), stearic acid, and magnesium oxide. These can be used alone or in combination of two or more. Examples of zinc oxide include zinc oxide type 1, zinc oxide type 2, zinc oxide type 3, and fine zinc oxide. The content of the crosslinking aid is not particularly limited, but is preferably 0.5 to 10 parts by mass, and more preferably 0.8 to 6 parts by mass, per 100 parts by mass of component (A).

[0066] <<Laminated Hose for Hydrogen Transfer>> This rubber composition is used as a material for the rubber layer constituting a laminated hose for hydrogen transfer. The laminated hose for hydrogen transfer includes, for example, a laminated structure comprising a rubber layer made of a crosslinked product of this rubber composition and a resin layer that serves as an adherend to the rubber layer. The laminated structure preferably has a cylindrical resin layer that forms a hydrogen gas flow passage (a so-called inner layer that forms the inner surface of the hose) and a cylindrical rubber layer laminated on the outer surface of the resin layer. The resin layer preferably contains a resin with good hydrogen barrier properties as its main component. Suitable resins include, for example, polyamides and ethylene-vinyl alcohol copolymers, but polyamides are particularly preferred. The polyamide is not particularly limited, but examples include aliphatic polyamides and semi-aromatic polyamides. Specifically, although not particularly limited, examples include nylon 4 (PA4), nylon 410 (PA410), nylon 6 (PA6), nylon 66 (PA66), nylon 610 (PA610), nylon 1010 (PA1010), nylon 1012 (PA1012), nylon 11 (PA11), and the like.

[0067] An example of the configuration of a laminated hose for hydrogen transfer will be described with reference to Figure 1. As shown in Figure 1, the laminated hose for hydrogen transfer comprises a resin layer 1 (inner layer), an inner rubber layer 2, a fiber layer 3, reinforcing yarn layers 41-46, intermediate rubber layers 51-56, and an outer rubber layer 6 (outer surface layer). As shown in Figure 1, the laminated hose for hydrogen transfer includes a resin layer 1 as the innermost layer. The resin layer 1 is formed in a cylindrical shape from a resin material with excellent hydrogen barrier properties, such as polyamide or ethylene-vinyl alcohol copolymer. An inner rubber layer 2 is provided on the outer circumferential surface of the resin layer 1. The inner rubber layer 2 is formed in a cylindrical shape from the aforementioned rubber composition. Furthermore, a fiber layer 3 is provided on the outer circumferential surface of the inner rubber layer 2. The fiber layer 3 has the function of restricting radial outward deformation of the inner rubber layer 2. The fiber layer 3 is formed in a cylindrical shape from, for example, a lattice-woven fiber sheet. Examples of materials applied to the fiber layer 3 include polyamide (nylon) fibers, aramid fibers, polyethylene terephthalate (PET) fibers, etc. The hydrogen transfer laminated hose further includes reinforcing yarn layers 41, 42, 43, 44, 45, and 46 that provide mechanical strength. For example, these reinforcing yarn layers 41, etc., are sequentially provided between the inner rubber layer 2 and the outer rubber layer 6, and each of the reinforcing yarn layers 41 to 46 has multiple reinforcing wires wound in a spiral shape, and metal is used for the reinforcing wires, such as copper wire, piano wire, hard steel wire, or stainless steel wire. The hydrogen transfer laminated hose further includes intermediate rubber layers 51, 52, 53, 54, 55, and 56. These intermediate rubber layers 51, etc., are formed in a cylindrical shape from rubber material. These intermediate rubber layers 51, etc., are arranged between each of the reinforcing yarn layers 41, etc., and also between the fiber layer 3 and the reinforcing yarn layers 41. The hydrogen transfer laminated hose has an outer rubber layer 6 on its outermost surface. The outer rubber layer 6 is formed in a cylindrical shape from rubber material.

[0068] An example of a method for manufacturing a laminated hose for hydrogen transfer will be explained with reference to one embodiment of the present invention shown in Figure 1. First, a resin layer 1 is formed by extruding a resin layer material containing polyamide or the like onto a mandrel using an extrusion molding machine. Next, the above components (A) to (E) and other components as needed are blended and kneaded using a kneader such as a roll, kneader, or Banbury mixer to obtain the rubber composition, which is then extruded onto the outer surface of the resin layer 1 to form an inner rubber layer 2. Furthermore, a strip-shaped sheet made of braided organic fibers is spirally wound onto the outer surface of the inner rubber layer 2 using a winding machine to form a mesh-like fiber layer 3. Subsequently, an intermediate rubber layer composition is extruded onto the outer surface of the fiber layer 3 to form an intermediate rubber layer 51. Next, a reinforcing yarn layer 41 is formed by spirally braiding brass plated wire or the like onto the outer surface of the intermediate rubber layer 51 using a braiding machine. Finally, an intermediate rubber composition is extruded onto the outer surface of the reinforcing yarn layer 41 to form an intermediate rubber layer 52. After sequentially forming intermediate rubber layers 53-56 and reinforcing yarn layers 42-46 using a similar method, the rubber composition for the outer rubber layer is extruded onto the outer surface of the reinforcing yarn layer 46 to form the outer rubber layer 6. Next, polyamide canvas is spirally braided onto the outer surface of the outer rubber layer 6, which forms the outer surface of the laminated hose for hydrogen transfer, using a braiding machine. After steam crosslinking this laminate (for example, at 150°C for 60 minutes), the polyamide canvas is removed to produce a 16-layer hose.

[0069] The dimensions of the laminated hydrogen transfer hose obtained in this way are not particularly limited, but the outer diameter is usually about 10 to 40 mm, and the total thickness (hose wall thickness) of the laminated hydrogen transfer hose is usually about 3 to 10 mm. Furthermore, the thickness of each layer constituting the laminated hydrogen transfer hose is not particularly limited as long as the intended function of each layer can be achieved, but for example, the thickness of the resin layer 1 is about 0.1 to 1.0 mm, and from the viewpoint of hydrogen barrier properties and hose handling, 0.3 to 0.7 mm is preferred. The thickness of the inner rubber layer 2 is about 1.0 to 2.0 mm, and from the viewpoint of hydrogen barrier properties and hose handling, 1.2 to 1.8 mm is preferred. The thickness of the intermediate rubber layer 51, etc., is about 0.1 to 1.0 mm each, and from the viewpoint of hose handling, 0.2 to 0.8 mm is preferred. The thickness of the outer rubber layer 6 is approximately 0.5 to 2.0 mm, and from the viewpoint of hose handling, etc., 1.0 to 1.5 mm is preferred.

[0070] In this invention, the inner rubber layer 2, the intermediate rubber layer 51, etc., and the outer rubber layer 6 may be composed of the same rubber composition. However, it is preferable that the forming material for the inner rubber layer 2 is the present rubber composition, and the intermediate rubber layer 51, etc., and the outer rubber layer 6 are general-purpose rubber layers made using a general-purpose rubber composition.

[0071] When forming the above-mentioned general-purpose rubber layer, the material is not particularly limited, but examples include natural rubber, ethylene-propylene-diene copolymer (EPDM), chloroprene rubber (CR), styrene-butadiene rubber (SBR), acrylic rubber (ACM), ethylene acrylate rubber (AEM), chlorinated polyethylene (CM), chlorosulfonated polyethylene (CSM), etc. Acrylonitrile butadiene rubber (NBR), hydrogenated acrylonitrile butadiene rubber (HNBR), fluororubber (FKM), etc. may also be used. These may be used alone or in combination of two or more. In addition, additives such as fillers and plasticizers may be appropriately blended into the rubber layer as needed. Among these, a rubber composition mainly composed of natural rubber and / or ethylene-propylene-diene copolymer (EPDM) is preferred as the material for forming the intermediate rubber layer 51 and the outer rubber layer 6.

[0072] Furthermore, the hydrogen transfer laminated hose according to the embodiment of the present invention is not limited to the 16-layer structure shown in Figure 1, but may also have a layered structure in which a resin layer, an inner rubber layer, a fiber layer, an intermediate rubber layer, a reinforcing yarn layer, and an outer layer are laminated in this order from the radially inner side. The number of intermediate rubber layers is arbitrary and can be appropriately set within a range of, for example, 2 to 10 layers, but preferably 2 to 8 layers.

[0073] Next, embodiments of the present invention will be described together with comparative examples. However, the present invention is not limited to these embodiments.

[0074] First, prior to the examples and comparative examples, the following materials were prepared as components (A) to (E).

[0075] [Ethylene-α-olefin-non-conjugated diene copolymer (component A)] (A-1) SUPRENE 552 EPDM (ENB ratio: 4.1% by mass, ethylene ratio: 58% by mass) manufactured by Ningbo SK Performance Rubber, Inc. (A-2) K9330M EBT (ENB ratio: 7.1% by mass, ethylene ratio: 50% by mass) manufactured by Mitsui Chemicals, Inc.

[0076] [Petroleum resin-based tackifier (component B)] (B-1) Petrotac® 100V, manufactured by Tosoh Corporation. Petroleum resin (aromatic monomer ratio 40% by mass) (B-2) Petcol® LX, manufactured by Tosoh Corporation. Petroleum resin (aromatic monomer ratio 100% by mass)

[0077] [Petroleum resin-based tackifier (component B')] (B'-1) Alcon® P-90 Hydrogenated petroleum resin (aliphatic monomer ratio 100% by mass), manufactured by Arakawa Chemical Industries, Ltd.

[0078] [Phenolic resin-based tackifier (component C)] (C-1) Taoka Chemical Co., Ltd., Tackiroll (registered trademark) EP-30 Alkylphenol acetaldehyde-based resin

[0079] [Bismaleimide compound (component D)] (D-1) N,N'-(1,3-phenylene)bismaleimide, manufactured by Tokyo Chemical Industry Co., Ltd.

[0080] [Crosslinking agents (component E)] (E-1) Perkmill® D-40B(K) [40% active ingredient], manufactured by NOF Corporation (E-2) Valnock® R sulfur-based crosslinking agent, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (E-3) SULFAX® PS sulfur-based crosslinking agent, manufactured by Tsurumi Chemical Industry Co., Ltd.

[0081] [Crosslinking accelerators] ・Crosslinking accelerator (1) Noxellar (registered trademark) TS, manufactured by Ouchi Shinko Chemical Industry Co., Ltd., thiuram-based crosslinking accelerator (tetramethylthiuram monosulfide (TMTM)) ・Crosslinking accelerator (2) Sunceller (registered trademark) M-G, manufactured by Sanshin Chemical Industry Co., Ltd., thiazole-based crosslinking accelerator (2-mercaptobenzothiazole (MBT))

[0082] [Co-crosslinking agent] ・Highcross (registered trademark) ED-P ethylene glycol dimethacrylate, manufactured by Seiko Chemical Co., Ltd.

[0083] [Paraffin Oil] - Manufactured by Idemitsu Kosan Co., Ltd., Diana Process PW-380

[0084] [Poly-alpha-olefin oil] - Manufactured by Nippon Steel Chemical & Material Co., Ltd., PAO401

[0085] [Carbon Black] - Tokai Carbon Co., Ltd., Seast (registered trademark) SO FEF grade carbon black

[0086] [Softener] ・HV-1900 Polybutene (Mn: 2900, kinematic viscosity (100°C): 3710 mm²) manufactured by Shin Nippon Petrochemical Co., Ltd. 2 / s)

[0087] [Crosslinking agent] ・Bead stearic acid, Sakura stearic acid, manufactured by NOF Corporation.

[0088] [Examples 1-12, Comparative Examples 1-3] Rubber compositions for rubber layers were prepared by kneading these components in the proportions shown in Table 1 below. Specifically, components (A), excluding components (D), (E), and the crosslinking accelerator, were added and kneaded in a 1.7 L Banbury mixer. Then, components (D), (E), and the crosslinking accelerator were added and mixed using an 8-inch roll to prepare the rubber composition for rubber layers. Note that the amount of peroxide-based crosslinking agent (E-1) in Table 1 represents the amount used in the product (Parkmill® D-40B(K)) and differs from the amount of active ingredient.

[0089] The rubber compositions for rubber layers obtained in the examples and comparative examples were evaluated for their properties according to the following criteria. These results are also shown in Table 1 below.

[0090] [Interlayer Adhesion Test (Resin-Rubber Adhesion Test)] One uncrosslinked rubber sheet (120 mm x 120 mm x 2 mm) of the rubber composition for the rubber layer was prepared. A 1 mm thick resin sheet (Arkema, BESNO P20TL (polyamide resin [PA11])) was placed on one of the rubber sheets, and the other rubber sheet was placed on top. The sheets were bonded by steam crosslinking at 160°C for 60 minutes. The integrated sheet was cut into 25 mm wide pieces to prepare test specimens. The rubber sheet and resin sheet in the test specimen were then pulled at 50 mm / min in a 180-degree direction under normal temperature conditions, and the peel strength was measured and evaluated according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) ○ (very good) ... Maximum peel strength of 50 N or more △ (good) ... Maximum peel strength of 20 N or more and less than 50 N × (poor) ... Maximum peel strength less than 20 N

[0091] [Interlayer Adhesion Test (Resin-Rubber Adhesion Test) under Low Temperature Environment] The peel strength was measured and evaluated according to the same criteria as above, except that the test conditions for the "Interlayer Adhesion Test (Resin-Rubber Adhesion Test)" were changed to a -40°C environment. The subjects of evaluation were Example 1 and Comparative Examples 1 to 3.

[0092] [Low-Temperature Flexibility Test (Gehman Torsion Test)] A sheet-like (crosslinked) test specimen (40 mm long, 3 mm wide, 2 mm thick) of the rubber composition for the rubber layer was prepared by crosslinking at 160°C for 60 minutes using a press molding machine. The obtained test specimens were subjected to a Gehman torsion test in accordance with JIS K6261 (2006), and the temperature T5 at which the specific modulus was 5 times that of the modulus at room temperature (23°C) was measured and evaluated according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) ◎ (excellent) ... Temperature T5 is less than -45°C 〇 (very good) ... Temperature T5 is -45°C or higher and less than -40°C △ (good) ... Temperature T5 is -40°C or higher and less than -35°C × (poor) ... Temperature T5 is -35°C or higher

[0093]

[0094] (Interlayer Adhesion Test) As shown in Table 1 above, the results indicate that, as in the comparative examples, the interlayer adhesion between the rubber layer and the resin layer is insufficient in laminated hoses for hydrogen transfer using rubber compositions that do not contain any of components (A) to (E). Specifically, in the case of a rubber layer that does not contain component (B) among components (A) to (E), as in Comparative Example 1; in the case of a rubber layer that does not contain component (C) among components (A) to (E), as in Comparative Example 2; and in the case of a rubber layer that does not contain component (D) among components (A) to (E), as in Comparative Example 3, the interlayer adhesion with the resin layer is insufficient.

[0095] Furthermore, the results shown in Table 1 above demonstrate that, as in the examples, a laminated hose for hydrogen transfer using a rubber composition containing all of components (A) to (E) exhibits excellent interlayer adhesion between the rubber layer and the resin layer.

[0096] Furthermore, when interlayer adhesion tests were conducted under low-temperature conditions (-40°C), Comparative Examples 1 to 3 showed a maximum peel strength of less than 20 N (rated as × (poor)), while Example 1 showed a maximum peel strength of 50 N or more (rated as ○ (very good)).

[0097] Based on the above results, it can be seen that, as in the present invention, a laminated hydrogen transfer hose using a rubber composition for a rubber layer containing all of components (A) to (E) exhibits good interlayer adhesion with a resin layer containing a resin with excellent hydrogen barrier properties, thus providing a laminated hydrogen transfer hose with excellent durability and, consequently, excellent hydrogen gas sealing properties.

[0098] (Low-temperature flexibility test (Gehman torsion test)) As shown in Table 1 above, the temperature T5 in the examples is less than -35°C, indicating good low-temperature flexibility. Therefore, the rubber composition for the rubber layer of the present invention tends to maintain its rubber elasticity even when used in low-temperature environments such as laminated hoses for hydrogen transfer. Thus, the laminated hose for hydrogen transfer of the present invention offers excellent durability and, consequently, hydrogen gas sealing properties, as well as good handling when connected to a dispenser installed at a hydrogen station.

[0099] While the above embodiments illustrate specific forms of the present invention, these embodiments are merely illustrative and should not be interpreted restrictively. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention.

[0100] The rubber composition for rubber layers of the present invention exhibits excellent interlayer adhesion, durability, and consequently, excellent hydrogen gas sealing properties in laminated hoses for hydrogen transfer, which include a laminated structure consisting of a rubber layer and a resin layer, making it useful as a material for laminated hoses for hydrogen transfer.

[0101] 1: Resin layer 2: Inner rubber layer 3: Fiber layer 41-46: Reinforcement yarn layer 51-56: Intermediate rubber layer 6: Outer rubber layer

Claims

1. A rubber composition for the rubber layer of a laminated hose used for hydrogen transfer, containing the following components (A) to (E): (A) Ethylene-α-olefin-non-conjugated diene copolymer (B) Petroleum resin-based tackifier containing constituent units derived from aromatic monomers (C) Phenolic resin-based tackifier (D) Bismaleimide compound (E) Crosslinking agent 2. The rubber composition for a rubber layer according to claim 1, wherein the mass ratio (B / C) of component (B) to component (C) is 0.4 to 2.

5.

3. The rubber composition for a rubber layer according to claim 1 or 2, wherein the total content of component (B) and component (C) (B + C) is 5 to 20 parts by mass per 100 parts by mass of component (A).

4. The rubber composition for a rubber layer according to any one of claims 1 to 3, wherein the above component (C) is an alkylphenol resin.

5. The rubber composition for a rubber layer according to any one of claims 1 to 4, wherein the above component (C) is an alkylphenol acetaldehyde resin.

6. A rubber composition for a rubber layer according to any one of claims 1 to 5, further comprising carbon black.

7. A rubber composition for a rubber layer according to any one of claims 1 to 6, further comprising poly-α-olefin oil.

8. The rubber composition for a rubber layer according to any one of claims 1 to 7, wherein the content of component (D) is 2 parts by mass or more per 100 parts by mass of component (A).

9. The rubber composition for a rubber layer according to any one of claims 1 to 8, wherein the (E) crosslinking agent contains a sulfur-based crosslinking agent and a peroxide-based crosslinking agent.

10. A laminated hose for hydrogen transfer comprising a resin layer containing at least one of polyamide and ethylene-vinyl alcohol copolymer, and a laminated structure in which a rubber layer is laminated on the outer surface of the resin layer, wherein the rubber layer is a rubber layer made of a crosslinked rubber composition for rubber layers according to any one of claims 1 to 9.

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