Rubber composition for hose and hose

Abstract

To provide a rubber composition excellent in toughness of an obtained rubber layer, adhesiveness between a resin layer and the rubber layer, and maintainability of strength of a reinforcing layer adjacent to the rubber layer, and to provide a hose.SOLUTION: A rubber composition for hoses, comprising: a rubber component having a BIMS content of 60 to 100% by mass and an EPDM content of 0 to 40% by mass; and at least one melamine compound selected from the group consisting of methylol melamines, methylol melamine alkyl ethers, and condensates thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rubber composition for a hose and a hose. [Background technology]

[0002] Conventionally, as a hose for transporting refrigerants (e.g., air conditioning hose) used in automobiles and the like, there has been known a hose having, for example, an innermost layer which is a resin layer containing a polyamide or the like with low gas permeability, a rubber layer formed on the innermost layer from a rubber composition containing a butyl-based rubber or the like, a reinforcing layer formed on the rubber layer from synthetic resin fibers or the like, and an outer tube on the reinforcing layer (e.g., Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4985878 Summary of the Invention [Problem to be solved by the invention]

[0004] To prevent leakage of the internal fluid (e.g., chlorofluorocarbon gas), hoses for transporting refrigerants must have a high resistance to refrigerant permeation in the innermost layer. At the same time, the rubber layer must be strong and have excellent adhesion between the resin layer, which is the innermost layer, and the rubber layer above it. Furthermore, in order for a hose for transporting a refrigerant to withstand high pressure, the reinforcing layer is required to have high strength. Under these circumstances, the present inventors prepared and evaluated a rubber composition with reference to Patent Document 1, and found that such a rubber composition leaves room for improvement in the toughness of the resulting rubber layer.

[0005] Therefore, an object of the present invention is to provide a rubber composition that provides a rubber layer with excellent toughness, adhesion between a resin layer and the rubber layer, and maintains the strength of a reinforcing layer adjacent to the rubber layer. The present invention also aims to provide a hose. [Means for solving the problem]

[0006] As a result of extensive research into solving the above problems, the present inventors have found that the problems can be solved by the following configuration. Specifically, the present invention solves the above problems by the following configuration.

[0007] [1] A rubber component having a BIMS content of 60 to 100 mass% and an EPDM content of 0 to 40 mass%; A rubber composition for a hose, comprising at least one melamine compound selected from the group consisting of methylolmelamines, methylolmelamine alkyl ethers, and condensates thereof. [2] The rubber composition for hoses according to [1], wherein the content of the melamine compound is 0.5 to 10 parts by mass per 100 parts by mass of the rubber component. [3] The rubber composition for a hose according to [1] or [2], further comprising talc, the content of the talc being 30 to 120 parts by mass per 100 parts by mass of the rubber component. [4] Further containing a halogenated alkylphenol formaldehyde resin and / or a phenolic resin,

[0023] When the rubber composition for a hose contains the halogenated alkylphenol formaldehyde resin, the content of the halogenated alkylphenol formaldehyde resin is 1 to 10 parts by mass per 100 parts by mass of the rubber component. [5] The rubber composition for a hose according to any one of [1] to [4], further comprising zinc oxide, the content of the zinc oxide being 2 to 10 parts by mass per 100 parts by mass of the rubber component. [6] A hose in which a resin layer, a rubber inner layer, a fiber reinforced layer, and a rubber outer layer are laminated in this order from the inner surface to the outer surface of the hose, the inner rubber layer and the fiber reinforced layer are adjacent to each other, the resin layer is a layer formed of a polyamide-based resin, the fiber reinforcement layer is a layer formed of polyethylene terephthalate fibers, The hose, wherein the inner rubber layer is a layer formed from a cured product of the rubber composition for a hose according to any one of [1] to [5]. [Effects of the Invention]

[0008] According to the present invention, a rubber composition can be provided that provides a rubber layer with excellent toughness, adhesion between a resin layer and a rubber layer, and strength retention of a reinforcing layer adjacent to the rubber layer. The present invention can also provide a hose. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic perspective view showing an example of a hose of the present invention, with each layer cut away. [Figure 2] FIG. 2 is a schematic perspective view of another example of a hose of the present invention, with each layer cut away. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below. The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment.

[0011] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. Unless otherwise specified, the method for producing each component is not particularly limited in this specification, and may be, for example, a conventionally known method. In this specification, unless otherwise specified, each component may be used alone or in combination of two or more substances. In this specification, when a component contains two or more substances, the content of the component means the total content of the two or more substances. In this specification, "the effects of the present invention are better" may mean that at least one of the toughness of the resulting rubber layer, the adhesion between the resin layer and the rubber layer, and the strength retention of the reinforcing layer adjacent to the rubber layer is better.

[0012] [Rubber composition for hoses] The rubber composition for a hose of the present invention (rubber composition of the present invention) will be described below. The rubber composition of the present invention comprises: a rubber component having a BIMS content of 60 to 100% by mass and an EPDM content of 0 to 40% by mass; The rubber composition for a hose contains at least one melamine compound selected from the group consisting of methylolmelamines, methylolmelamine alkyl ethers, and condensates thereof.

[0013] [Rubber component] The rubber composition of the present invention contains a rubber component, and the rubber component contains BIMS and optionally contains EPDM.

[0014] [BIMS] The rubber composition of the present invention contains BIMS as the rubber component. In the present invention, the BIMS is not particularly limited as long as it is a brominated copolymer rubber of isomonoolefin and p-alkylstyrene, and examples thereof include those known in the art. There are no particular restrictions on which repeating units of the BIMS are brominated. In one preferred embodiment, a portion of the repeating units of the p-alkylstyrene in the copolymer rubber is brominated. In other words, in the above case, the BIMS may have, for example, repeating units of an isomonoolefin, repeating units of an unbrominated p-alkylstyrene, and repeating units of a brominated p-alkylstyrene.

[0015] (Isomonoolefin) The isomonoolefins constituting the above BIMS have terminal C *It is a hydrocarbon compound having a branched structure of -(CH3)2 and one double bond at another end. When the carbon number of the isomonoolefin is 4, the above C * C in -(CH3)2 * can form a double bond.

[0016] Carbon number of isomonoolefin The carbon number of the isomonoolefin is preferably 4 to 7, and more preferably 4, from the viewpoint of achieving better effects of the present invention.

[0017] Examples of the isomonoolefins include isobutylene (also called isobutene, 2-methyl-1-propene), 3-methyl-1-butene (also called isopentene), 4-methyl-1-pentene (also called isohexene), and 5-methyl-1-hexene (also called isoheptene). Among these, the isomonoolefin is preferably isobutylene from the viewpoint of achieving the effects of the present invention more excellently.

[0018] (p-Alkylstyrene) The p-alkylstyrene constituting BIMS is a styrene having an alkyl group at the p-position. In one preferred embodiment of BIMS, some of the repeating units of the p-alkylstyrene are brominated at the alkyl group of the p-alkylstyrene.

[0019] Examples of the alkyl group contained in the p-alkylstyrene include alkyl groups having 1 to 8 carbon atoms, such as a methyl group and an ethyl group. Of these, p-methylstyrene is preferred as the p-alkylstyrene from the viewpoint of achieving the effects of the present invention more excellently.

[0020] (Content of repeating units having bromine) From the viewpoint of achieving a more excellent effect of the present invention, the content of the bromine-containing repeating units constituting the BIMS is preferably 0.8 to 1.5 mol % based on the total amount of repeating units constituting the BIMS. BIMS does not include either butyl rubber or halogenated butyl rubber.

[0021] [BIMS content] In the rubber composition of the present invention, the content of BIMS is 60 to 100% by mass of the total amount of the rubber component. From the viewpoint of achieving better effects of the present invention, the content of BIMS is preferably 90 to 100% by mass, and more preferably 100% by mass, of the total amount of the rubber component. In addition, the content of BIMS is preferably 30 to 80% by mass of the total amount of the rubber composition of the present invention, from the viewpoint of achieving better effects of the present invention.

[0022] [EPDM] The rubber composition of the present invention optionally includes EPDM. EPDM (ethylene-propylene-diene rubber) is a copolymer of ethylene, propylene, and a third diene component. EPDM contains double bonds derived from the diene component. In the present invention, the EPDM is not particularly limited, and examples thereof include conventionally known EPDMs. Examples of the diene component constituting EPDM include non-diene monomers such as ethylidene norbornene (ENB), 1,4-hexadiene (1,4-HD), and dicyclopentadiene (DCP), and among these, ENB is preferred. The content of the diene component in the EPDM is preferably 7 to 11% by mass.

[0023] (Mooney viscosity) From the viewpoint of achieving superior effects of the present invention, the Mooney viscosity of the EPDM at 100°C is preferably 41 or more, more preferably 60 or more, and even more preferably 70 or more. On the other hand, the upper limit of the Mooney viscosity is not particularly limited, but can be, for example, 120 or less. The Mooney viscosity is measured in accordance with JIS K6300-1-2013 using an L-shaped rotor, with a preheating time of 1 minute, rotor rotation time of 4 minutes, and a test temperature of 100°C (ML 1+4 , 100℃).

[0024] [EPDM content] In the rubber composition of the present invention, the content of EPDM is 0 to 40% by mass of the total amount of the rubber component. When the rubber composition of the present invention contains EPDM, the content of EPDM is preferably 10 to 30% by mass of the total amount of the rubber component, from the viewpoint of achieving better effects of the present invention.

[0025] (Other rubber) When the total content of BIMS and any EPDM is less than 100% by mass of the total rubber component, the rubber component may further contain other rubbers in addition to BIMS and EPDM, such as halogenated butyl rubber and butyl rubber.

[0026] [Melamine compounds] The rubber composition of the present invention contains at least one melamine compound selected from the group consisting of methylolmelamines, methylolmelamine alkyl ethers, and condensates thereof. In the present invention, the melamine compound can function as a methylene donor. The melamine compound can be decomposed into formaldehyde and the like by heat during vulcanization, for example.

[0027] (Methylol melamines) Methylolmelamines, which are melamine compounds, are compounds in which 1 to 6 formaldehyde groups are added to the three amino groups (-NH2) that melamine has. In the present invention, the methylolmelamines do not include methylolmelamine alkyl ethers, which will be described later. Examples of methylolmelamines include monomethylolmelamine and hexamethylolmelamine.

[0028] (Methylolmelamine alkyl ethers) Methylol melamine alkyl ethers as melamine compounds are compounds in which at least a part or all of the methylol groups (hydroxymethyl groups) of the above-mentioned methylol melamines have been alkyl-etherified. Examples of methylolmelamine alkyl ethers include hexamethylolmelamine pentamethyl ether (structure shown below), [ka]

[0029] An example is hexamethylolmelamine hexamethyl ether (structure shown below). [ka]

[0030] (condensation product) In the present invention, the condensate as the melamine compound is a condensate of the above-mentioned methylolmelamines and / or the above-mentioned methylolmelamine alkyl ethers. Examples of the condensates of the methylolmelamine alkyl ethers include condensates of hexamethylolmelamine pentamethyl ether and condensates of hexamethylolmelamine hexamethyl ether. The condensate may be a partial condensate of the methylolmelamines and / or the methylolmelamine alkyl ethers.

[0031] Examples of the condensate of hexamethylolmelamine pentamethyl ether include compounds represented by the following formula (n in the following formula is 2 to 3). [ka]

[0032] Examples of the condensation product of hexamethylolmelamine hexamethyl ether include compounds represented by the following formula (n in the following formula is 2 to 3). [ka]

[0033] The melamine compound preferably contains the above-mentioned methylol melamine alkyl ethers and / or condensates thereof, more preferably a mixture of hexamethylol melamine pentamethyl ether and a condensate thereof, or hexamethylol melamine hexamethyl ether and / or a condensate thereof, and even more preferably hexamethylol melamine pentamethyl ether and / or a condensate thereof, because this provides better effects of the present invention.

[0034] The melamine compound may be a mixture of at least one melamine compound selected from the group consisting of the above-mentioned methylol melamines, methylol melamine alkyl ethers, and condensates thereof, silica, and paraffinic oil. An example of a commercially available product of the above mixture is SUMIKANOL 507AP (manufactured by BARA CHEMICAL CO., LTD.).

[0035] (Melamine compound content) From the viewpoint of achieving a better effect of the present invention, the content of the melamine compound (when the melamine compound is a mixture as described above, the net content of the melamine compound) is preferably 0.5 to 10 parts by mass, more preferably 1.0 to 4.0 parts by mass, and even more preferably 1.0 to 3.0 parts by mass, per 100 parts by mass of the rubber component (total amount).

[0036] (talc) From the viewpoint of achieving better effects of the present invention, the rubber composition of the present invention preferably further contains talc. Talc is a mineral composed of magnesium hydroxide and silicate, Mg3Si4O 10 It is a compound represented by (OH)2. The talc that can be further contained in the rubber composition of the present invention is not particularly limited, and examples thereof include conventionally known talc.

[0037] Talc content When the rubber composition of the present invention further contains talc, the content of talc is preferably 30 to 120 parts by mass per 100 parts by mass of the rubber component (total amount), from the viewpoint of achieving better effects of the present invention.

[0038] (Halogenated alkylphenol formaldehyde resin and / or phenolic resin) From the viewpoint of achieving better effects of the present invention, the rubber composition of the present invention preferably further contains a halogenated alkylphenol formaldehyde resin and / or a phenol resin, and more preferably contains a halogenated alkylphenol formaldehyde resin. In the present invention, the phenol resin does not include halogenated alkylphenol formaldehyde resin. The halogenated alkylphenol formaldehyde resin and the phenolic resin can function as a crosslinking aid for the BIMS.

[0039] Halogenated alkylphenol formaldehyde resin In the present invention, the halogen contained in the halogenated alkylphenol formaldehyde resin is not particularly limited, and examples thereof include chlorine and bromine. Examples of halogenated alkylphenol formaldehyde resins that may be contained in the rubber composition of the present invention include brominated alkylphenol formaldehyde resins (specifically, for example, condensates of brominated alkylphenols and formaldehyde).

[0040] Halogenated alkylphenol formaldehyde resin content When the rubber composition of the present invention further contains a halogenated alkylphenol formaldehyde resin, the content of the halogenated alkylphenol formaldehyde resin is preferably 1 to 10 parts by mass, more preferably 4 to 6 parts by mass, per 100 parts by mass of the rubber component (total amount), from the viewpoint of more excellent effects of the present invention.

[0041] (phenolic resin) The phenol resin that can be contained in the rubber composition of the present invention includes, for example, an alkylphenol resin, more specifically, a condensate of an alkylphenol and formaldehyde. The alkylphenol includes, for example, a phenol having an alkyl group having 1 to 10 carbon atoms.

[0042] Phenolic resin content When the rubber composition of the present invention further contains a phenolic resin, the content of the phenolic resin is preferably 1 to 20 parts by mass, more preferably 5 to 10 parts by mass, per 100 parts by mass of the rubber component (total amount), from the viewpoint of achieving better effects of the present invention.

[0043] (zinc oxide) The rubber composition of the present invention preferably further contains zinc oxide (ZnO). Zinc oxide can function as a crosslinker for BIMS. The zinc oxide is not particularly limited, and examples thereof include conventionally known zinc oxides.

[0044] Zinc oxide content From the viewpoint of achieving a better effect of the present invention, the content of zinc oxide is preferably 2 to 10 parts by mass, more preferably 4 to 6 parts by mass, per 100 parts by mass of the rubber component (total amount).

[0045] (carbon black) The rubber composition of the present invention preferably further contains carbon black (CB). There are no particular limitations on the CB. For example, conventionally known CBs can be used.

[0046] From the viewpoint of achieving better effects of the present invention, the CB preferably contains at least one or more types selected from the group consisting of ISAF carbon black, HAF carbon black, SRF carbon black, and FT carbon black, more preferably contains ISAF carbon black, HAF carbon black, or a combination of SRF carbon black and FT carbon black, and even more preferably contains ISAF carbon black.

[0047] Carbon black content From the viewpoint of achieving better effects of the present invention, the content of CB is preferably 10 to 200 parts by mass, more preferably 20 to 50 parts by mass, per 100 parts by mass of the rubber component (total amount).

[0048] (additives) The rubber composition of the present invention may further contain additives as needed, provided that the effects of the present invention are not impaired. Examples of additives include softeners such as stearic acid, silica, and paraffin oil, and antioxidants. The types and contents of the various additives can be selected appropriately. In addition, when the melamine compound is a mixture, a part or all of the silica may be compounded in the rubber composition of the present invention. The same applies to the paraffinic oil.

[0049] In one preferred embodiment, the rubber composition of the present invention does not contain resorcinols. In this specification, examples of resorcinols include resorcinol and formaldehyde resins of resorcinol.

[0050] (Method of manufacturing rubber composition) The method for producing the rubber composition of the present invention is not particularly limited. For example, the rubber composition can be produced by mixing the above-mentioned essential components and optional components that can be used as needed, for example, at a temperature of 20 to 180°C.

[0051] (Crosslinking of rubber composition) The method for crosslinking the rubber composition of the present invention is not particularly limited. The rubber composition of the present invention can be crosslinked (vulcanized) by, for example, press vulcanization, steam vulcanization, oven vulcanization (hot air vulcanization), or hot water vulcanization under conditions of 140 to 190°C and a pressure of 1.0 to 4.0 MPa. In the present invention, crosslinking the rubber composition of the present invention means crosslinking the (uncrosslinked) rubber composition of the present invention to harden it. Specifically, it is sufficient that the rubber component contained in the rubber composition of the present invention is crosslinked. In this specification, crosslinking may be referred to as vulcanization for convenience.

[0052] (Application) The rubber composition of the present invention is excellent in maintaining the strength of the reinforcing layer (for example, a synthetic resin fiber layer or fiber-reinforced layer) adjacent to the obtained rubber layer, and can therefore be used adjacent to the reinforcing layer. The rubber composition of the present invention can be used for a hose, and specifically, for example, can be used for a hose for transporting a refrigerant.

[0053] [hose] The hose of the present invention is A hose in which a resin layer, a rubber inner layer, a fiber reinforced layer, and a rubber outer layer are laminated in this order from the inner surface to the outer surface of the hose, the inner rubber layer and the fiber reinforced layer are adjacent to each other, the resin layer is a layer formed of a polyamide-based resin, the fiber reinforcement layer is a layer formed of polyethylene terephthalate fibers, The inner rubber layer is a layer formed from a cured product of the rubber composition for a hose of the present invention.

[0054] The hose of the present invention may have one or more fiber-reinforced layers. When the hose of the present invention has multiple fiber-reinforced layers, it may further have an intermediate rubber layer between the multiple fiber-reinforced layers.

[0055] The configuration of the hose of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the accompanying drawings. Note that the reference numerals shown in the drawings are shown in parentheses in the following description. (Figure 1) FIG. 1 is a schematic perspective view showing an example of a hose of the present invention, with each layer cut away. In FIG. 1, the hose (10) has a resin layer (12), an inner rubber layer (18), a fiber reinforced layer (14), and an outer rubber layer (16). The resin layer 12 is the innermost layer of the hose 10. The inner rubber layer 18 is adjacent to the fiber reinforced layer 14. The resin layer 12 is adjacent to the inner rubber layer 18. The inner rubber layer 18 is a rubber layer formed from the rubber composition of the present invention. The outer rubber layer 16 is not particularly limited. For example, a conventionally known rubber layer can be used. Specifically, one preferable embodiment of the outer rubber layer 16 is a rubber layer having excellent weather resistance. In Fig. 1, the hose 10 has one fiber reinforcement layer 14. The fiber reinforcement layer 14 may be, for example, a fiber reinforcement layer formed of fibers braided into a braid shape.

[0056] (Figure 2) FIG. 2 is a schematic perspective view of another example of a hose of the present invention, with each layer cut away. In FIG. 2, the hose (20) has a resin layer (22), an inner rubber layer (28), fiber reinforcement layers (24), (25), an outer rubber layer (26), and an intermediate rubber layer (27). The resin layer 22 is the innermost layer of the hose 20. The rubber inner layer 28 is adjacent to the fiber reinforced layer 24. The resin layer 22 is adjacent to the rubber inner layer 28. The inner rubber layer (28) is a rubber layer formed from the rubber composition of the present invention. An intermediate rubber layer (27) is disposed between the fiber reinforcement layers (24) and (25). The rubber outer layer 26 is not particularly limited. For example, a conventionally known rubber layer can be used. Specifically, one preferable embodiment of the rubber outer layer 26 is a rubber layer having excellent weather resistance. In Fig. 2, the hose 20 has two fiber reinforcement layers, namely, fiber reinforcement layers 24 and 25. Examples of the fiber reinforcement layers 24 and 25 include fiber reinforcement layers formed of spirally braided fibers.

[0057] [Resin layer] The hose of the present invention has a resin layer, and the resin layer is a layer formed from a polyamide resin. The polyamide resin is not particularly limited, but preferably includes polyamide; or modified polyamide of polyamide and carboxyl group-containing modified polyolefin. Examples of the polyamide include polyamide resins such as nylon 11, nylon 12, nylon 6, nylon 66, nylon 666, nylon 612, nylon 610, and nylon 46. The polyamides used in the modified polyamides are similar to the above polyamides. The carboxyl group-containing modified polyolefin may be any modified polyolefin having a carboxyl group (—COOH). The modified polyamide can be obtained, for example, by blending a polyamide with a carboxyl group-containing modified polyolefin. Commercially available modified polyamides include, for example, the Zytel ST series, such as Zytel ST801, Zytel ST811, and Zytel ST811HS, manufactured by DuPont. In addition to the modified polyamide, the resin layer may further contain, for example, additives. Examples of additives include white fillers such as carbon black and silica, vulcanizing or crosslinking agents, vulcanization or crosslinking accelerators, oils, and antioxidants. The content of the additives can be appropriately selected within a range that does not contradict the object of the present invention. The resin layer may be a layer formed from a resin composition that contains, for example, an additive in addition to the modified polyamide.

[0058] (resin layer thickness) The thickness of the resin layer is not particularly limited, but can be, for example, 0.05 to 0.30 mm. (innermost layer) In a preferred embodiment, the hose of the present invention has a resin layer as the innermost layer of the hose of the present invention.

[0059] [Rubber inner layer] The hose of the present invention has an inner rubber layer, which is a layer formed from a cured product of the rubber composition for a hose of the present invention. The rubber composition used for the inner rubber layer is not particularly limited as long as it is the rubber composition of the present invention. (resin layer thickness) The thickness of the inner rubber layer is not particularly limited, but can be, for example, 0.2 to 3 mm. (adjacent to the resin layer) The inner rubber layer is preferably disposed adjacent to and above the resin layer.

[0060] [Fiber reinforcement layer] The hose of the present invention has a fiber reinforcement layer, and the fiber reinforcement layer is a layer formed of polyethylene terephthalate fibers. The fiber reinforcement layer may be a layer formed from polyethylene terephthalate (PET) fibers. Examples of polyethylene terephthalate (PET) fibers that form the fiber reinforcement layer include untreated PET fibers and PET fibers treated with RFL (resorcinol-formaldehyde-latex adhesive). The fiber reinforcement layer may have, for example, a spiral or braided structure. The hose of the present invention may have one or more fiber reinforced layers. (thickness of fiber reinforcement layer) The thickness of each fiber reinforcement layer is not particularly limited, but can be, for example, 0.3 to 3 mm.

[0061] (adjacent to the inner rubber layer) The fiber reinforcement layer is adjacent to the inner rubber layer. When the hose of the present invention has a plurality of fiber reinforcement layers, it is sufficient that one of the plurality of fiber reinforcement layers is disposed adjacent to the inner rubber layer. When the hose of the present invention has a plurality of fiber reinforcement layers, the plurality of fiber reinforcement layers may be disposed between the inner rubber layer and the outer rubber layer described below.

[0062] (Intermediate rubber layer) When the hose of the present invention has a plurality of fiber-reinforced layers, it may further have an intermediate rubber layer between the plurality of fiber-reinforced layers. When the hose of the present invention further has an intermediate rubber layer, the material of the intermediate rubber layer is not particularly limited as long as it is, for example, a rubber composition that has excellent adhesion to the fiber-reinforced layer. The thickness of the intermediate rubber layer may be, for example, 0.1 to 3 mm.

[0063] [Rubber outer layer] The hose of the present invention has an outer rubber layer. The material of the outer rubber layer is not particularly limited. For example, it may be the same as the rubber material used in the outermost layer of a conventional hose. Specifically, one preferred embodiment is a rubber layer with excellent weather resistance. (thickness of fiber reinforcement layer) The thickness of the outer rubber layer is not particularly limited, but can be, for example, 0.2 to 3 mm. (outermost layer) In the hose of the present invention, the rubber outer layer can be the outermost layer of the hose of the present invention.

[0064] Laminate In the hose of the present invention, the resin layer, the inner rubber layer, the fiber reinforcement layer, and the outer rubber layer are laminated in this order from the inner surface to the outer surface of the hose, and the inner rubber layer and the fiber reinforcement layer are adjacent to each other. In one preferred embodiment, the resin layer, the inner rubber layer, the fiber reinforcement layer, and the outer rubber layer are laminated in this order and adjacent to one another. Furthermore, when the hose of the present invention has a plurality of the fiber reinforcement layers and an intermediate rubber layer between the plurality of fiber reinforcement layers, one preferred embodiment is that the resin layer, the inner rubber layer, N sets of the fiber reinforcement layer and the intermediate rubber layer, the fiber reinforcement layer, and the outer rubber layer are laminated in this order and adjacent to each other. The number N can be 1 to 10.

[0065] (Hose manufacturing method) The hose of the present invention can be produced by any method, including, for example, laminating on a mandrel a resin composition for forming the resin layer, a composition of the present invention for forming the inner rubber layer, PET fibers for forming the first fiber-reinforced layer, a rubber composition for the intermediate rubber layer, PET fibers for forming the second fiber-reinforced layer, and a rubber composition for forming the outer rubber layer in a manner consistent with the desired hose configuration to form a laminate, and then crosslinking (vulcanizing) the laminate by press vulcanization, steam vulcanization, oven vulcanization (hot air vulcanization), or hot water vulcanization at 140 to 190°C for 30 to 180 minutes to integrate the laminate. In the above, the hose of the present invention may be produced by covering the laminate before crosslinking with a protective film made of, for example, polymethyl terpene, crosslinking as described above, and then peeling the protective film from the crosslinked laminate.

[0066] The hose of the present invention can be used, for example, as a hose for transporting a refrigerant. Specific applications of the hose of the present invention include, for example, a hose for a car air conditioning system and a hose for an indoor air conditioning system. [Example]

[0067] The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the following examples.

[0068] [Production of rubber composition] Each rubber composition was produced by mixing the components in the composition (parts by mass) shown in Table 1 below with a stirrer. In addition, in the melamine compound column of Table 1, *1 The figure in the upper right is the total amount of commercially available melamine compounds used, and the figure in the lower right is the total amount of melamine compounds used *2 The value in parentheses is the net amount of melamine compound in the above-mentioned commercially available product. The above-mentioned commercially available product will be described later. In addition, in Blend 1 in Table 1 below, Comparative Example 1 differs from Examples 1 and 2 in the presence or absence of a melamine compound. The same applies to Blend 2 in the same table, Comparative Example 2 and Examples 3 and 4, Blend 3, Comparative Example 3 and Examples 5 to 7, and Blend 4, Comparative Example 4 and Examples 8 and 9.

[0069] [evaluation] The rubber compositions produced as described above were subjected to the following evaluations, and the results are shown in Table 1.

[0070] [Toughness of rubber layer] (Preparation of test specimens) Each rubber composition produced as described above was press-crosslinked in a press molding machine at 160° C. for 100 minutes (surface pressure 3.0 MPa) to obtain a crosslinked sheet (thickness 2 mm) as a cured product. JIS No. 3 dumbbell-shaped test pieces were punched out from each of the crosslinked sheets obtained as described above to prepare the respective test pieces. (Tensile test) Using each test piece obtained as described above, a tensile test was performed in accordance with JIS K6251:2017 under conditions of 23°C and a tensile speed of 500 mm / min to measure the elongation at break (EB) [unit: %]. The results of the elongation at break (EB) are shown in the "Toughness of rubber layer" column in Table 1.

[0071] (Evaluation criteria for toughness of rubber layer) In the present invention, when the EB was 120% or more, the rubber layer was evaluated as having excellent toughness. The greater the EB than 120%, the more excellent the toughness of the rubber layer, which is preferable.

[0072] [Adhesion between resin layer and rubber layer] (Sample preparation) Each rubber composition obtained as described above was cut into two unvulcanized rubber sheets each having a thickness of 3 mm. Next, a 0.2 mm thick sheet of modified polyamide (trade name Zytel ST811HS (manufactured by DuPont; an alloy blended with polyamide 6 and carboxyl group-containing modified polyolefin)) was sandwiched between two of the above unvulcanized rubber sheets to form a three-layer laminate, which was then press-vulcanized at 160°C and a press pressure of 2 MPa for 100 minutes to produce a strip-shaped sample 25 mm wide and 150 mm long. (Peel force measurement) Using a Strograph E3-L (Toyo Seiki Seisakusho, Ltd.), one end of the sample obtained as described above (one end with a width of 25 mm) was gripped with one vulcanized rubber layer and the remaining two layers, and pulled vertically at a peel rate of 50 mm / min to measure the peel force. The obtained peel force was divided by 25 to calculate the average peel force (unit: kN / m). The peel force obtained as described above is shown in the "Rubber / Resin Adhesion" column of each table. (Evaluation criteria for adhesion between resin layer and rubber layer) In the present invention, when the peel strength obtained as described above was 1.5 kN / m or more, the adhesion between the resin layer and the rubber layer was evaluated as excellent. The greater the peel strength is from 1.5 kN / m, the better and more preferable the adhesion between the resin layer and the rubber layer is.

[0073] [Maintenance of strength between the rubber layer and the adjacent reinforcing layer] (Creating a sample) Unvulcanized hose test piece An unvulcanized sheet having a thickness of 2.5 mm prepared from each rubber composition obtained as described above was wound around an iron mandrel having an outer diameter of 35 mm, and then a twisted yarn of polyethylene terephthalate fiber (not RFL-treated) was spirally wound around it to form a fiber-reinforced layer. Next, an unvulcanized sheet identical to the unvulcanized sheet described above was again attached onto the fiber-reinforced layer to prepare an unvulcanized hose-shaped test piece. Vulcanized hose specimens Next, the unvulcanized hose-shaped test piece prepared as described above was oven-vulcanized at 160°C for 100 minutes to obtain a vulcanized hose-shaped test piece. The vulcanized hose-shaped test piece had a three-layer structure consisting of, from the inner layer, a rubber layer, a fiber-reinforced layer, and another rubber layer. Hose test piece after heat resistance test The vulcanized hose-shaped test piece obtained as described above was left at 135° C. for 96 hours, and then gradually cooled to room temperature to obtain a hose-shaped test piece after the heat resistance test. Sample preparation The surface rubber layer was cut out from the longitudinal center of the hose-shaped test piece obtained as described above after the heat resistance test, and the surface rubber layer was peeled off along the circumference of the hose to expose the fiber reinforcement layer, thereby preparing a sample.

[0074] (Measurement of the strength of the reinforcing layer) Fibers were removed from the sample, which was a hose-shaped test piece after vulcanization with the fiber reinforcement layer exposed as described above, and the fiber removed from the sample was pulled using an Autograph ASG-X (Shimadzu Corporation) at a pulling rate of 300 mm / min to measure the strength of the fiber of the hose-shaped test piece after vulcanization. On the other hand, the strength of the fiber before vulcanization was measured by pulling the twisted yarn of the polyethylene terephthalate fiber as it was at a pulling speed of 300 mm / min using an Autograph ASG-X (Shimadzu Corporation). (Calculation of fiber strength reduction rate) The strength obtained as described above was applied to the following formula to determine the reduction rate of the fiber strength. The reduction rate of the fiber strength is shown in the "Reduced Tenacity Rate" column of Table 1. Fiber strength reduction rate (%) = (AB) / A × 100 A: Strength of fiber before vulcanization B: Strength of the fiber of the hose-shaped test piece after vulcanization (Evaluation criteria for maintaining the strength of the rubber layer and the adjacent reinforcing layer) In the present invention, when the reduction rate obtained as described above is 50% or less, the strength retention of the reinforcing layer adjacent to the rubber layer is evaluated as excellent. The smaller the reduction rate is below 50%, the better and more preferable the retention is.

[0075] [Table 1]

[0076] [Table 2]

[0077] Details of each component shown in Table 1 are as follows: BIMS: Exxpro 3745, manufactured by EXXONMOBIL CHEMICAL COMPANY. A brominated copolymer rubber in which p-methylstyrene in a copolymer rubber of a C4 isomonoolefin (isobutylene) and p-methylstyrene is brominated to form bromomethylstyrene. The content of the bromomethylstyrene repeat unit was 1.2 mol% of the total amount of repeat units constituting the BIMS.

[0078] (EPDM) EPDM: Mitsui EPT4070, manufactured by Mitsui Chemicals, Inc. Diene component: ENB, Diene content: 8.1% by mass, Mooney viscosity at 100°C: 89

[0079] (carbon black) ISAF CB: ISAF grade carbon black. Nitelon #300, manufactured by Nippon Steel Carbon Co., Ltd. HAF CB: HAF grade carbon black. DASH BLACKN 330, manufactured by OCI Company Ltd. SRF CB: SRF grade carbon black. Nitelon #SY, manufactured by Nippon Steel Carbon Co., Ltd. FT CB: FT carbon black. Nitelon #20Y, manufactured by Nippon Steel Carbon Co., Ltd.

[0080] Talc: ImerFlex T20, manufactured by Imerys Specialties Japan Co., Ltd. Stearic acid: Palmera B1810, manufactured by KLK OLEO

[0081] (melamine compounds) Melamine compound: Trade name Sumikanol 507AP (manufactured by BARA CHEMICAL CO., LTD.). A mixture of 65% by mass of the compound (hexamethylolmelamine pentamethyl ether) with the following structure, its dimer and oligomer as condensation products, 32% by mass of silica, and 3% by mass of paraffinic oil. [ka]

[0082] Softener: Paraffin oil. Product name: Machine Oil 22, manufactured by Showa Shell Sekiyu K.K. Zinc oxide: Product name: Zinc oxide type 3, manufactured by Seido Chemical Industry Co., Ltd. Brominated alkylphenol formaldehyde resin: Trade name: Tackirol 250-I, manufactured by Taoka Chemical Co., Ltd. The above product, Tackirol 250-I, does not contain resorcinols. Phenolic resin: Product name: PR 2501Y, manufactured by Showa Denko Materials Co., Ltd. The PR 2501Y product is a mixture containing 96% or more by mass of phenolic resin, 3.0% by mass of p-octylphenol, toluene, etc. The product does not contain resorcinols or brominated alkylphenol formaldehyde resins.

[0083] From the results in Table 1, it was confirmed that the rubber composition of the present invention exhibits the desired effects.

[0084] On the other hand, in Comparative Examples 1 to 4, which did not contain the specific melamine compound, at least one of the toughness of the resulting rubber layer, the adhesion between the resin layer and the rubber layer, and the strength retention of the reinforcing layer adjacent to the rubber layer was insufficient. [Explanation of symbols]

[0085] 10, 20 hose 12, 22 Resin layer 14, 24, 25 Fiber reinforcement layer 16, 26 Rubber outer layer 18, 28 Rubber inner layer 27 Middle rubber layer

Claims

1. a rubber component having a BIMS content of 60 to 100% by mass and an EPDM content of 0 to 40% by mass; A rubber composition for a hose, comprising at least one melamine compound selected from the group consisting of methylolmelamines, methylolmelamine alkyl ethers, and condensates thereof.

2. 2. The rubber composition for a hose according to claim 1, wherein the content of the melamine compound is 0.5 to 10 parts by mass based on 100 parts by mass of the rubber component.

3. 2. The rubber composition for a hose according to claim 1, further comprising talc, the content of said talc being 30 to 120 parts by mass per 100 parts by mass of said rubber component.

4. Further containing a halogenated alkylphenol formaldehyde resin and / or a phenol resin, 2. The rubber composition for a hose according to claim 1, wherein, when the rubber composition contains the halogenated alkylphenol formaldehyde resin, the content of the halogenated alkylphenol formaldehyde resin is 1 to 10 parts by mass per 100 parts by mass of the rubber component.

5. 2. The rubber composition for a hose according to claim 1, further comprising zinc oxide, the content of said zinc oxide being 2 to 10 parts by mass per 100 parts by mass of said rubber component.

6. A hose in which a resin layer, a rubber inner layer, a fiber reinforced layer, and a rubber outer layer are laminated in this order from the inner surface to the outer surface of the hose, the inner rubber layer and the fiber reinforced layer are adjacent to each other, the resin layer is a layer formed of a polyamide-based resin, the fiber reinforcement layer is a layer formed of polyethylene terephthalate fibers, A hose, wherein the inner rubber layer is a layer formed from a cured product of the rubber composition for a hose according to any one of claims 1 to 5.

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