Rubber composition, multilayer structure, and hose

Abstract

To provide a rubber composition that features excellent compression set resistance in a rubber layer formed therefrom, superior adhesiveness between a resin layer and the rubber layer, and high strength retention of a reinforcing layer adjacent to the rubber layer.SOLUTION: The present invention provides a rubber composition including: from 1 to 15 pts.mass of a phenolic resin; and 0.05 pt.mass or more and less than 1 pt.mass of fatty acid, relative to 100 pts.mass of a rubber component containing from 30 to 100 pts.mass of a bromide of a copolymer rubber of an isomonoolefin and a p-alkylstyrene, from 0 to 70 pts.mass of a halogenated butyl rubber, and from 0 to 70 pts.mass of a butyl rubber, as well as a multilayer structure and a hose containing the rubber composition.SELECTED DRAWING: None

Description

[Technical field]

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

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

[0003] [Patent Document 1] JP 2002-79614 A Summary of the Invention [Problem to be solved by the invention]

[0004] Hoses for transporting refrigerants require high refrigerant permeability resistance in the innermost layer to prevent leakage of the internal fluid (e.g., fluorocarbon gas). They are also required to have excellent resistance to compression set in the rubber layer and excellent adhesion between the resin layer, which is the innermost layer, and the rubber layer above the innermost layer. Furthermore, in order for a hose for transporting a refrigerant to withstand high pressure, the reinforcing layer is required to have high strength. In this situation, the present inventors prepared and evaluated a rubber composition with reference to Patent Document 1, and found that such a rubber composition may have poor at least one of the following: compression set resistance of the resulting rubber layer, adhesion between the resin layer and the rubber layer, and strength retention of the reinforcing layer adjacent to the rubber layer. The inventors considered that the decrease in strength of the reinforcing layer adjacent to the rubber layer was due to the fact that when the rubber layer is formed from a rubber composition containing a butyl rubber, a fatty acid (e.g., stearic acid) as a processing aid, and a resin crosslinking agent, and the reinforcing layer is formed from synthetic resin fibers, the fatty acid (e.g., stearic acid) and the resin crosslinking agent deteriorate the synthetic resin fibers. It is believed that the deterioration of the synthetic resin fibers as described above shortens the life of the hose product.

[0005] Therefore, an object of the present invention is to provide a rubber composition which provides a rubber layer excellent in compression set resistance, adhesion between a resin layer and a rubber layer, and strength retention of a reinforcing layer adjacent to the rubber layer. Another object of the present invention is to provide a laminate and a hose. [Means for solving the problem]

[0006] As a result of intensive research to solve the above problems, the present inventors have found that by reducing the amount of fatty acid or phenolic resin, which is a resin crosslinking agent, in the rubber composition, deterioration of the fiber layer (fiber reinforcement layer) can be suppressed even if the rubber composition contains fatty acid and a resin crosslinking agent. Furthermore, they have found that the desired effect can be obtained by making the rubber composition contain 1 to 15 parts by mass of a phenolic resin and 0.05 parts by mass or more and less than 1 part by mass of a fatty acid per 100 parts by mass of rubber component containing 30 to 100 parts by mass of a brominated copolymer rubber of isomonoolefin and p-alkylstyrene, 0 to 70 parts by mass of a halogenated butyl rubber, and 0 to 70 parts by mass of butyl rubber, and have arrived at the present invention. The present invention is based on the above findings and has the following specific configuration to solve the above problems.

[0007] [1] A rubber composition comprising 100 parts by mass of a rubber component including 30 to 100 parts by mass of a brominated copolymer rubber of isomonoolefin and p-alkylstyrene, 0 to 70 parts by mass of a halogenated butyl rubber, and 0 to 70 parts by mass of a butyl rubber, and further comprising 1 to 15 parts by mass of a phenolic resin and 0.05 part by mass or more but less than 1 part by mass of a fatty acid. [2] The rubber composition according to [1], wherein the content of the brominated compound is 50 to 100 parts by mass per 100 parts by mass of the rubber component. [3] The rubber composition according to [1] or [2], wherein the content of the phenol-based resin per 100 parts by mass of the rubber component is 1 to 5 parts by mass. [4] The rubber composition according to any one of [1] to [3], wherein the content of the fatty acid per 100 parts by mass of the rubber component is 0.1 part by mass or more and less than 1 part by mass. [5] A rubber sheet having a resin layer, a rubber layer, and a fiber layer, the resin layer is a layer containing a modified polyamide of a polyamide and a carboxyl group-containing modified polyolefin, The rubber layer is a layer formed from a cured product of the rubber composition according to any one of [1] to [4], The laminate, wherein the fiber layer is a layer of polyethylene terephthalate fiber. [6] The innermost layer is a resin layer, a rubber layer 1, a fiber reinforcement layer, and a rubber layer 2, the resin layer is a layer containing a modified polyamide of a polyamide and a carboxyl group-containing modified polyolefin, The rubber layer 1 is a layer formed from a cured product of the rubber composition according to any one of [1] to [4], The hose, wherein the fiber reinforcement layer is a layer of polyethylene terephthalate fiber. Effect of the Invention

[0008] According to the present invention, a rubber composition can be provided which provides a rubber layer with excellent compression set resistance, excellent adhesion between a resin layer and a rubber layer, and excellent strength retention of a reinforcing layer adjacent to the rubber layer. The present invention can provide a laminate and a hose. [Brief description 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described in detail below. In this specification, a numerical range expressed using "~" means a range including the numerical values ​​written before and after "~". In the present specification, unless otherwise specified, the production method of each component is not particularly limited. For example, a conventionally known method may be used. In this specification, unless otherwise specified, each component may be used alone or in combination of two or more substances corresponding to that component. 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 "brominated copolymer rubber of isomonoolefin and p-alkylstyrene" is also referred to as the "specific bromide." In this specification, the term "the effects of the present invention are superior" may mean that at least one of the compression set resistance of the obtained 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 superior.

[0011] [Rubber composition] The rubber composition of the present invention comprises: The rubber composition contains 100 parts by mass of a rubber component including 30 to 100 parts by mass of a brominated copolymer rubber of isomonoolefin and p-alkylstyrene (specific brominated product), 0 to 70 parts by mass of a halogenated butyl rubber, and 0 to 70 parts by mass of a butyl rubber, and further contains 1 to 15 parts by mass of a phenolic resin and 0.05 part by mass or more but less than 1 part by mass of a fatty acid.

[0012] Since the rubber composition of the present invention has such a structure, it is believed that the desired effects can be obtained. It is presumed that the excellent strength retention of the reinforcing layer adjacent to the rubber layer is due to the fact that the content of the fatty acid and the phenolic resin contained in the rubber composition is within a predetermined range, thereby reducing the attack (e.g., hydrolysis) of the fatty acid and / or the phenolic resin on the fiber layer (fiber reinforcing layer). Each component contained in the rubber composition of the present invention will be described in detail below.

[0013] [Rubber component] In the present invention, the rubber component contains, per 100 parts by mass of the rubber component, 30 to 100 parts by mass of a brominated copolymer rubber of isomonoolefin and p-alkylstyrene (specific brominated product), 0 to 70 parts by mass of a halogenated butyl rubber, and 0 to 70 parts by mass of a butyl rubber.

[0014] [Specific brominated substances] In the present invention, the brominated copolymer rubber of isomonoolefin and p-alkylstyrene (specific brominated compound) is not particularly limited. There is no particular restriction as to which repeating unit is brominated among all repeating units constituting the specific bromide.One of the preferred embodiments is that a part of the repeating units of the above-mentioned p-alkylstyrene of the copolymer rubber is brominated.That is, in the above case, the specific bromide can have, for example, a repeating unit of isomonoolefin, a repeating unit of non-brominated p-alkylstyrene, and a repeating unit of brominated p-alkylstyrene.

[0015] <Isomonoolefin> The isomonoolefin constituting the specific bromide compound has a 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 The isomonoolefin preferably has 4 to 7 carbon atoms, and more preferably 4, from the viewpoint of achieving superior effects of the present invention.

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

[0018] <p-アルキルスチレン> The p-alkylstyrene constituting the specific bromide is a styrene having an alkyl group at the p-position. In one preferred embodiment of the specific bromide, a portion of the repeating units of the p-alkylstyrene is 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, the p-alkylstyrene is preferably p-methylstyrene from the viewpoint of achieving superior effects of the present invention.

[0020] (Content of repeating units having bromine) From the viewpoint of achieving superior effects of the present invention, the content of the bromine-containing repeating units constituting the specific bromide is preferably 0.8 to 1.5 mol % based on the total amount of repeating units constituting the specific bromide. The specific brominated compounds do not include butyl rubber and halogenated butyl rubber.

[0021] (Butyl rubber) The butyl rubber that may be contained in the rubber composition of the present invention is not particularly limited. For example, a general isobutylene-isoprene copolymer rubber may be used. The content of isoprene in the butyl rubber can be, for example, 0.6 to 3.0 mol % based on the total amount of repeating units constituting the butyl rubber. In addition, butyl rubber does not include specific brominated and halogenated butyl rubber.

[0022] (Halogenated butyl rubber) The halogenated butyl rubber that may be contained in the rubber composition of the present invention is not particularly limited. Examples of the halogenated butyl rubber include chlorinated butyl rubber and brominated butyl rubber. When the halogenated butyl rubber contains a chlorinated butyl rubber, the chlorine content in the chlorinated butyl rubber can be 1 to 2.5 mass %. The isoprene content can be, for example, 0.6 to 3.0 mol % of the total amount of repeating units constituting the chlorinated butyl rubber. When the halogenated butyl rubber contains a brominated butyl rubber, the bromine content in the brominated butyl rubber can be 1 to 2.5 mass %. The isoprene content can be, for example, 0.6 to 3.0 mol % of the total amount of repeating units constituting the brominated butyl rubber. In addition, halogenated butyl rubber does not include specific brominated compounds and butyl rubber.

[0023] [Specific brominated substance content] In the present invention, the content of the specific brominated compound is 30 to 100 parts by mass in 100 parts by mass of the rubber component. The content of the specific brominated compound is preferably 50 to 100 parts by mass, more preferably 80 to 100 parts by mass, and even more preferably 100 parts by mass, in 100 parts by mass of the rubber component, from the viewpoint of achieving superior effects of the present invention.

[0024] [Halogenated butyl rubber content] In the present invention, the content of the halogenated butyl rubber is 0 to 70 parts by mass in 100 parts by mass of the rubber component. The content of the halogenated butyl rubber is preferably 0 to 50 parts by mass in 100 parts by mass of the rubber component, from the viewpoint of achieving superior effects of the present invention.

[0025] [Butyl rubber content] In the present invention, the content of the butyl rubber is 0 to 70 parts by mass in 100 parts by mass of the rubber component. The content of the butyl rubber is preferably 0 to 50 parts by mass in 100 parts by mass of the rubber component, from the viewpoint of achieving superior effects of the present invention.

[0026] (Total content of specific brominated substances, halogenated butyl rubber and butyl rubber) From the viewpoint of obtaining superior effects of the present invention, the total content of the specific brominated compound, the halogenated butyl rubber, and the butyl rubber is preferably more than 80 parts by mass and not more than 100 parts by mass, more preferably 90 to 100 parts by mass, and even more preferably 100 parts by mass, per 100 parts by mass of the rubber component.

[0027] (Other rubber) When the total content of the specific brominated compound, halogenated butyl rubber, and butyl rubber is less than 100 parts by mass per 100 parts by mass of the rubber component, the rubber component may further contain rubber other than the specific brominated compound, halogenated butyl rubber, and butyl rubber. The content of EPDM (ethylene propylene diene copolymer rubber) as the other rubber can be 0 parts by mass or less than 20 parts by mass in 100 parts by mass of the rubber component, with 0 part by mass being a preferred embodiment.

[0028] [Phenol resin and fatty acid] The rubber composition of the present invention contains 1 to 15 parts by mass of a phenolic resin based on 100 parts by mass of the rubber component. The rubber composition of the present invention contains 0.05 part by mass or more and less than 1 part by mass of a fatty acid per 100 parts by mass of the rubber component.

[0029] [Phenol-based resin] The phenol-based resin contained in the rubber composition of the present invention includes, for example, an alkylphenol resin. The phenolic resin contained in the rubber composition of the present invention can function, for example, as a crosslinking agent for butyl rubber and a crosslinking assistant for specific brominated compounds.

[0030] From the viewpoint of achieving superior effects of the present invention, the phenol-based resin preferably contains an alkylphenol resin, and more preferably contains a brominated alkylphenol resin. Examples of the alkylphenol resin include condensates of alkylphenols and formaldehyde; and halogenated alkylphenol resins such as brominated alkylphenol resins. An example of the brominated alkylphenol resin is a brominated alkylphenol formaldehyde resin (a condensate of a brominated alkylphenol and formaldehyde).

[0031] [fatty acid] In the present invention, the fatty acid refers to an aliphatic hydrocarbon compound having one carboxy group. The aliphatic hydrocarbon group of the fatty acid is not particularly limited. The aliphatic hydrocarbon group may be either a saturated or unsaturated aliphatic hydrocarbon group. The fatty acid may, for example, include at least one fatty acid having a total carbon number of 14 to 18. In this specification, the total carbon number of a fatty acid is sometimes represented as "C**". C14 fatty acids include, for example, saturated fatty acids such as myristic acid; and unsaturated fatty acids such as myristoleic acid. C16 fatty acids include, for example, saturated fatty acids such as palmitic acid; and unsaturated fatty acids such as palmitoleic acid. Examples of C18 fatty acids include saturated fatty acids such as stearic acid; and unsaturated fatty acids such as oleic acid and linoleic acid. From the viewpoint of achieving a better effect of the present invention, the fatty acid preferably contains a fatty acid having a total of at least 18 carbon atoms, and more preferably contains stearic acid.

[0032] In addition, commercially available products can be used as the fatty acid. Examples of the commercially available products include fatty acids generally simply called "stearic acid" and containing fatty acids such as C18, or industrial stearic acid. Industrial stearic acid is usually a mixture of fatty acids such as C18 (e.g., stearic acid, oleic acid), C16 (e.g., palmitic acid, palmitoleic acid), and C14 (e.g., myristic acid, myristoleic acid). Commercially available fatty acids include, for example, Beads Stearic Acid (manufactured by NOF Corporation), Stearic Acid YR (manufactured by NOF Corporation), Lunac YA (manufactured by Kao Corporation), and Stearic Acid 50S (manufactured by Nisshin Rika Co., Ltd.).

[0033] [Phenol resin content] The amount of the phenol-based resin per 100 parts by mass of the rubber component is preferably 1 to 5 parts by mass, from the viewpoint of obtaining superior effects of the present invention. [Fatty acid content] The amount of the fatty acid per 100 parts by mass of the rubber component is preferably 0.1 part by mass or more and less than 1 part by mass, and more preferably 0.3 part by mass or more and less than 1 part by mass, from the viewpoint of obtaining superior effects of the present invention.

[0034] (Additives) The rubber composition of the present invention may further contain additives as necessary within the range not impairing the effects of the present invention. Examples of additives include white fillers such as carbon black, talc, and silica, plasticizers such as paraffin oil, zinc oxide, and antioxidants.

[0035] (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.

[0036] (Dibutyl phthalate oil absorption of carbon black) From the viewpoint of achieving superior effects of the present invention, the dibutyl phthalate oil absorption amount (DBP oil absorption amount) of CB is preferably 15 to 80 ml / 100 g. The dibutyl phthalate oil absorption (DBP oil absorption) of carbon black can be measured in accordance with JIS K 6217-4:2008 "Carbon black for rubber - Basic properties - Part 4: Determination of oil absorption (including compressed samples)".

[0037] (Amount of iodine adsorbed by carbon black) The iodine adsorption amount of CB is preferably 10 to 40 mg / g, from the viewpoint of obtaining a more excellent effect of the present invention. In the present invention, the iodine adsorption amount of carbon black can be measured in accordance with JIS K6217-1:2008.

[0038] From the viewpoint of achieving better effects of the present invention, the CB preferably contains carbon black from a fine thermal furnace (FTF), a general purpose furnace (GPF), or a semi-reinforcing furnace (SRF), and more preferably contains carbon black from an FTF and / or an SRF.

[0039] (Carbon black content) The content of CB is preferably 40 to 200 parts by mass, and more preferably 80 to 150 parts by mass, based on 100 parts by mass of the rubber component, from the viewpoint of achieving superior effects of the present invention.

[0040] (silica) The rubber composition of the present invention may further contain silica, and from the viewpoint of obtaining superior effects of the present invention, it is preferable that the rubber composition further contains silica. The silica that may be further contained in the rubber composition of the present invention is not particularly limited. Examples of silica include natural silica, fused silica, amorphous silica, hollow silica, and fumed silica. The content of silica can be set to 0 to 20 parts by mass based on 100 parts by mass of the rubber component, and from the viewpoint of obtaining superior effects of the present invention, it is preferably set to 1 to 10 parts by mass.

[0041] (talc) From the viewpoint of obtaining superior effects of the present invention, it is preferable that the rubber composition of the present invention further contains talc. Talc is a mineral composed of magnesium hydroxide and silicate, Mg3Si4O 10 It is a compound represented by (OH)2. The content of the talc is preferably 10 to 80 parts by mass based on 100 parts by mass of the rubber component, from the viewpoint of obtaining superior effects of the present invention.

[0042] (Zinc Oxide) The rubber composition of the present invention preferably further contains zinc oxide (ZnO). Zinc oxide can function as a cross-linking agent for certain bromides. The zinc oxide is not particularly limited, and examples thereof include those that are conventionally known. The content of zinc oxide is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the rubber component, from the viewpoint of achieving superior effects of the present invention.

[0043] (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 essential components and optional components that can be used as needed under conditions of, for example, 20 to 180°C.

[0044] (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.

[0045] (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, a fiber-reinforced layer) adjacent to the obtained rubber layer, and therefore can be used adjacent to the reinforcing layer. The rubber composition of the present invention can be used, for example, for a hose, and specifically, for example, for a hose for transporting a refrigerant.

[0046] [Laminate] The laminate of the present invention has a resin layer, a rubber layer, and a fiber layer, the resin layer is a layer containing a modified polyamide of a polyamide and a carboxyl group-containing modified polyolefin, The rubber layer is a layer formed from a cured product of the rubber composition of the present invention, The laminate is such that the fiber layer is a layer of polyethylene terephthalate fiber. In the laminate of the present invention, the resin layer, the rubber layer, and the fiber layer are laminated adjacent to each other in the order of the resin layer, the rubber layer, and the fiber layer.

[0047] [Resin layer] The resin layer of the laminate of the present invention is a layer containing a modified polyamide of a polyamide and a 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, nylon 46, and nylon 66612. 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. The resin layer may further contain, for example, additives in addition to the modified polyamide. Examples of additives include white fillers such as carbon black and silica, vulcanizing agents or crosslinking agents, vulcanization accelerators or crosslinking accelerators, oils, and antioxidants. The content of the additives may be appropriately selected within a range that does not contradict the object of the present invention. The resin layer may be, for example, a layer formed from a resin composition that further contains, for example, an additive in addition to the modified polyamide.

[0048] [Rubber layer] The rubber layer in the laminate of the present invention is a layer formed from a cured product of the rubber composition of the present invention. The rubber composition used in the rubber layer is not particularly limited as long as it is the rubber composition of the present invention.

[0049] [Fiber layer] The fiber layer in the laminate of the present invention is a layer of polyethylene terephthalate (PET) fibers. The fiber layer may be any layer formed from PET fibers. Examples of polyethylene terephthalate (PET) fibers forming the fiber layer include untreated PET fibers and PET fibers treated with RFL (resorcinol-formaldehyde-latex adhesive). The form of the fiber layer may be, for example, a spiral or braided structure.

[0050] (An additional rubber layer on top of the fiber layer) The laminate of the present invention may further have a rubber layer or the like on the fiber layer. When a rubber layer is further provided on the fiber layer, the further rubber layer on the fiber layer is not particularly limited. For example, a conventionally known rubber layer can be mentioned. Specifically, for example, a rubber layer having excellent weather resistance can be mentioned as one of the preferable embodiments of the further rubber layer on the fiber layer. The further rubber layer on the fiber layer may be a layer formed by a cured product of the rubber composition of the present invention, and in this case, the rubber layer on the resin layer and the further rubber layer on the fiber layer may be the same or different.

[0051] (Method of manufacturing laminate) As a method for producing the laminate of the present invention, for example, a method for producing the laminate of the present invention by stacking the resin composition for the resin layer, the rubber composition of the present invention, and the PET fiber for the fiber layer in this order and heating them in the stacked state can be mentioned. By heating them in the stacked state as described above, the resin composition, the rubber composition of the present invention, and the fiber layer can be integrated. When the laminate of the present invention further has a rubber layer or the like on the fiber layer, a material corresponding to the rubber layer or the like may be further used. The heating conditions include, for example, placing the mixture at 140 to 190° C. under a pressure of 1.0 to 4.0 MPa for 30 to 180 minutes.

[0052] The laminate of the present invention can be applied, for example, to a hose, specifically, for example, to a hose for transporting a refrigerant. The laminate of the present invention can be used, for example, as part of a hose.

[0053] [hose] The hose of the present invention is The innermost layer is a resin layer, a rubber layer 1, a fiber reinforcement layer, and a rubber layer 2, the resin layer is a layer containing a modified polyamide of a polyamide and a carboxyl group-containing modified polyolefin, The rubber layer 1 is a layer formed from a cured product of the rubber composition of the present invention, The hose, wherein the fiber reinforcement layer is a layer of polyethylene terephthalate fiber.

[0054] The hose of the present invention has, in order from the innermost layer, a resin layer, a rubber layer 1, a fiber reinforcement layer, and a rubber layer 2. In the hose of the present invention, the resin layer, the rubber layer 1, the fiber reinforcement layer, and the rubber layer 2 are laminated adjacently in the above order from the innermost layer. The resin layer becomes the innermost layer.

[0055] [Resin layer] The hose of the present invention has a resin layer as an innermost layer. The resin layer in the hose of the present invention corresponds to and is similar to the resin layer in the laminate of the present invention. The thickness of the resin layer is not particularly limited, but can be, for example, 0.05 to 0.30 mm. [Rubber layer 1] The hose of the present invention has a rubber layer 1. The rubber layer 1 in the hose of the present invention corresponds to and is similar to the rubber layer adjacent to the resin layer in the laminate of the present invention. The thickness of the rubber layer 1 is not particularly limited, but may be, for example, 0.2 to 3 mm. [Fiber reinforcement layer] The hose of the present invention has a fiber reinforcement layer. The fiber reinforcement layer in the hose of the present invention corresponds to and is similar to the fiber layer in the laminate of the present invention. The thickness of the fiber reinforcement layer is not particularly limited, but may be, for example, 0.3 to 3 mm. [Rubber layer 2] The hose of the present invention has a rubber layer 2. The rubber layer 2 in the hose of the present invention corresponds to and is similar to the additional rubber layer on the fiber layer in the laminate of the present invention. The thickness of the rubber layer 2 is not particularly limited, but may be, for example, 0.2 to 3 mm. In the hose of the present invention, the rubber layer 2 may be the outermost layer.

[0056] The configuration of the hose of the present invention will be described with reference to the attached drawings. The present invention is not limited to the attached drawings. In the following description, the reference numerals shown in the drawings are shown in parentheses. 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 (1) has a resin layer (21), a rubber layer 1 (22), a fiber reinforcement layer (3), and a rubber layer 2 (4). The rubber layer 1 (22) is a rubber layer formed from the rubber composition of the present invention. The rubber layer 2(4) is not particularly limited. For example, a conventionally known rubber layer may be used. Specifically, one of the preferred embodiments of the rubber layer 2(4) is a rubber layer having excellent weather resistance. The rubber layer 2(4) may be a layer formed of a cured product of the rubber composition of the present invention. In this case, the rubber layer 1(22) and the rubber layer 2(4) may be the same or different.

[0057] (Hose manufacturing method) The hose of the present invention is not particularly limited by its manufacturing method. For example, the resin composition for forming the resin layer, the composition of the present invention for forming the rubber layer 1, PET fibers for forming the fiber reinforcement layer, and the rubber composition for forming the rubber layer 2 are laminated on a mandrel so as to form a laminate in the form of a desired hose, and the laminate is crosslinked (vulcanized) by press vulcanization, steam vulcanization, oven vulcanization (hot air vulcanization), or hot water vulcanization under conditions of 140 to 190°C and 30 to 180 minutes to integrate the laminate, thereby producing the hose of the present invention. In the above, the laminate before crosslinking may be covered with a protective film, for example made of polymethylterpene, crosslinked as described above, and then the protective film may be peeled off from the crosslinked laminate to produce the hose of the present invention.

[0058] 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. EXAMPLES

[0059] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these.

[0060] <Production of Rubber Composition> Each rubber composition was produced by mixing the components in the respective tables shown below in the compositions (parts by mass) shown in the tables with a stirrer.

[0061] <Evaluation> The rubber compositions produced as described above were subjected to the following evaluations, and the results are shown in Table 1.

[0062] <Compression set resistance of rubber layer> Each of the obtained rubber compositions was press-vulcanized for 45 minutes under conditions of 153°C and a surface pressure of 3.5 MPa using a press molding machine having a mold with a diameter of 29.05 mm and a thickness of 12.5 mm to prepare disc-shaped test specimens (the diameter of the disc-shaped test specimens was 29.0±0.5 mm and the thickness was 12.5±0.5 mm). Using the above test pieces, a compression set test was performed according to JIS K6262:2013 under the conditions of a test temperature of 70°C, a test time of 22 hours, and a compression ratio of 25%, to measure the compression set (%). The results of the compression set are shown in each table as an index, with the result of Example 9 being 1.0.

[0063] · Evaluation criteria for compression set In the present invention, when the compression set (index) is 2.5 or less, the compression set resistance of the obtained rubber layer is evaluated as excellent and is indicated by "◯". Excellent compression set resistance of the rubber layer means excellent sealing properties of the laminate or hose. The smaller the compression set (index) is from 2.5, the better the compression set resistance of the rubber layer is. On the other hand, when the compression set (index) exceeded 2.5, the compression set resistance of the resulting rubber layer was evaluated as poor and was indicated by "X".

[0064] <Adhesion between resin layer and rubber layer> Sample preparation Each of the rubber compositions obtained as described above was cut into two unvulcanized rubber sheets having a thickness of 2 mm. Next, a modified polyamide (an alloy blended with polyamide 6 and a carboxyl group-containing modified polyolefin, formed into a 0.2 mm thick sheet) was sandwiched between two of the above unvulcanized rubber sheets to form a three-layer laminate, which was then press-vulcanized for 45 minutes at 153°C and a press pressure of 2 MPa to produce a rectangular sample 25 mm wide and 150 mm long. Peel force measurement Using a Strograph E3-L (Toyo Seiki Seisakusho Co., Ltd.), one vulcanized rubber layer and the remaining two layers were each gripped at one end (one end with a width of 25 mm) of the sample obtained as described above, and pulled up and down at a peeling speed of 50 mm / min to measure the peeling force. The obtained peeling force was divided by 25 to calculate the average peeling force (unit: N / mm), which is shown in the "Peel Force (average)" column in each table. Peel strength evaluation criteria In the present invention, when the peel strength obtained as described above exceeds 1.0 N / mm, the adhesion between the resin layer and the rubber layer is evaluated as excellent and is indicated by "◯." The greater the peel strength is 1.0 N / mm, the better the adhesion between the resin layer and the rubber layer. On the other hand, when the peel strength was 1.0 N / mm or less, the adhesion between the resin layer and the rubber layer was evaluated as poor and this was indicated by "X".

[0065] <Maintenance of strength between the rubber layer and the adjacent reinforcing layer> Sample preparation 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 wound in a spiral shape to form a fiber-reinforced layer. Next, the same unvulcanized sheet as the unvulcanized sheet described above was attached again onto the fiber-reinforced layer to prepare an unvulcanized hose-shaped test piece. Next, a nylon 66 curing tape (protective cloth) was wrapped around the outside of the unvulcanized hose-shaped test piece prepared as above, and oven vulcanization was performed for 100 minutes under the condition of 160°C. After vulcanization, the curing tape was removed 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 reinforcement layer, and a rubber layer. At the longitudinal center portion of the vulcanized hose-shaped test piece obtained as described above, the surface rubber layer was cut out and peeled off along the circumference of the hose to expose the fiber reinforcement layer. -Measurement of the strength of the reinforcing layer Fibers were removed from the sample, which was the 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 speed 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 above polyethylene terephthalate fiber as it was at a pulling speed of 300 mm / min using an Autograph ASG-X (Shimadzu Corporation). The strength obtained as described above was applied to the following formula to determine the reduction rate of the fiber strength. Fiber strength reduction rate (%) = (BA) / A x 100 A: Strength of fiber before vulcanization B: Strength of the fibers of the hose-shaped test specimen after vulcanization Evaluation criteria for fiber strength loss rate In the present invention, when the reduction rate obtained as described above is greater than -80% (reduction rate > -80%), the strength retention of the reinforcing layer adjacent to the rubber layer is evaluated as excellent, and this is indicated as "◯". The greater the reduction rate is greater than -80%, the better the retention. On the other hand, when the rate of decrease was −80% or less, the maintenance was evaluated as being poor and was indicated by “×”.

[0066] [Table 1]

[0067] [Table 2]

[0068] [Table 3]

[0069] Details of each component shown in the above tables are as follows: (Specific Brominated Substances) Special brominated materials (BIMS): Exxpro 3745, manufactured by EXXONMOBIL CHEMICAL COMPANY. Brominated copolymer rubber in which p-methylstyrene in a copolymer rubber of an isomonoolefin (isobutylene) having 4 carbon atoms and p-methylstyrene is brominated and converted to bromomethylstyrene. The content of the repeating unit of the bromomethylstyrene was 1.2 mol% based on the total amount of repeating units constituting the BIMS.

[0070] (Halogenated butyl rubber) ·Br-IIR: Brominated butyl rubber (bromobutyl rubber represented by the following formula). Exxon Bromobutyl 2255, manufactured by Japan Butyl Co., Ltd. The above brominated butyl rubber does not fall under the category of specific brominated substances because it does not have a repeating unit of p-alkylstyrene. [ka]

[0071] (Butyl rubber) ·IIR: Butyl rubber. Exxon Butyl 268, manufactured by Japan Butyl Co., Ltd. The butyl rubber does not contain repeating units of p-alkylstyrene and is not brominated, so it does not fall under the category of specific brominated substances. The butyl rubber does not contain halogens, so it does not fall under the category of halogenated butyl rubber.

[0072] (Carbon Black) Carbon black: SRF carbon black. DBP absorption 64±12cm 3 / 100g, iodine adsorption capacity 23±5mg / g.

[0073] Silica: Nipsil AQ (Tosoh Silica) acidic silica

[0074] Talc: Mistron Vapor (Made by Japan Mistron Co., Ltd.)

[0075] (fatty acid) Fatty acid: stearic acid. Product name: Stearic acid 50S, manufactured by Nisshin Rika Co., Ltd.

[0076] (Phenol Resin) Phenolic resin: Brominated alkylphenol formaldehyde resin. Takkiroll 250-I, manufactured by Taoka Chemical Co., Ltd.

[0077] Paraffin oil: Machine oil, manufactured by Showa Shell Sekiyu

[0078] ZnO: Zinc oxide. Three types of zinc oxide, manufactured by Seido Chemical Industry Co., Ltd.

[0079] From the results shown in Table 1, it can be seen that in Comparative Example 1, in which the contents of the specific brominated compound and the butyl rubber were outside the prescribed ranges, the adhesion between the resin layer and the rubber layer was poor. Comparative Example 2, which did not contain a phenolic resin or a fatty acid, had poor compression set resistance of the rubber layer and poor adhesion between the resin layer and the rubber layer. In Comparative Examples 3 and 5, which contained 1 part by mass of fatty acid, the reinforcing layer had poor strength retention. In Comparative Example 4, which contained 16 parts by mass of a phenol-based resin, the reinforcing layer had poor strength retention. In Comparative Examples 6 to 8, in which the content of the phenolic resin was less than 1 part by mass, the adhesion between the resin layer and the rubber layer was poor. In Comparative Example 9, which did not contain fatty acid, the rubber layer had poor compression set resistance. Comparative Example 10, which did not contain a phenolic resin, had poor adhesion between the resin layer and the rubber layer.

[0080] In contrast, the rubber composition of the present invention provides an excellent compression set resistance of the obtained rubber layer, excellent adhesion between the resin layer and the rubber layer, and excellent strength retention of the reinforcing layer adjacent to the rubber layer. The laminate of the present invention was excellent in the compression set resistance of the rubber layer, the adhesion between the resin layer and the rubber layer, and the strength retention of the fiber layer adjacent to the rubber layer. The hose of the present invention is excellent in resistance to compression set of the rubber layer, adhesion between the resin layer and the rubber layer, and strength retention of the fiber reinforcing layer adjacent to the rubber layer. [Explanation of symbols]

[0081] 1 Hose 21 Resin layer 22 Rubber layer 1 3 Fiber reinforcement layer 4 Rubber layer 2

Claims

1. The rubber composition contains 100 parts by mass of a rubber component including 30 to 100 parts by mass of a brominated copolymer rubber of isomonoolefin and p-alkylstyrene, 0 to 70 parts by mass of a halogenated butyl rubber, and 0 to 70 parts by mass of a butyl rubber, and further contains 1 to 15 parts by mass of a phenolic resin and 0.05 part by mass or more but less than 1 part by mass of a fatty acid.

2. The rubber composition according to claim 1, wherein the content of the brominated compound is 50 to 100 parts by mass based on 100 parts by mass of the rubber component.

3. The rubber composition according to claim 1, wherein the content of the phenol-based resin per 100 parts by mass of the rubber component is 1 to 5 parts by mass.

4. The rubber composition according to claim 1, wherein a content of the fatty acid per 100 parts by mass of the rubber component is 0.1 parts by mass or more and less than 1 part by mass.

5. A resin layer, a rubber layer, and a fiber layer are included. the resin layer is a layer containing a modified polyamide of a polyamide and a carboxyl group-containing modified polyolefin, The rubber layer is a layer formed from a cured product of the rubber composition according to any one of claims 1 to 4, A laminate, wherein the fiber layer is a layer of polyethylene terephthalate fibers.

6. The innermost layer is a resin layer, a rubber layer 1, a fiber reinforcement layer, and a rubber layer 2, the resin layer is a layer containing a modified polyamide of a polyamide and a carboxyl group-containing modified polyolefin, The rubber layer 1 is a layer formed of a cured product of the rubber composition according to any one of claims 1 to 4, The hose, wherein the fiber reinforcement layer is a layer of polyethylene terephthalate fiber.

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