Industrial hose

Abstract

To provide an industrial hose having good heat resistance, and having good adhesive property between a plated wire layer 4 and an intermediate rubber layer 3.SOLUTION: An industrial hose includes a layered structure in which an inner rubber layer 1, an organic fiber layer 2, an intermediate rubber layer 3, and a plated wire layer 4 are stacked in this order. The inner rubber layer 1 is made of a rubber composition containing components (A) to (D), where the total content (B+C) of the component (B) and the component (C) is 0.8-2.2 pts.mass with respect to 100 pts.mass of the component (A), and a mass ratio (B / C) of (B) component with respect to (C) component is 1.8-18: (A) a rubber component containing acrylonitrile butadiene rubber; (B) at least one of sulfene-based amide vulcanization accelerator and thiazole vulcanization accelerator; (C) a thiuram vulcanization accelerator; and (D) N-phenyl-N-(trichloromethylthio)benzene sulfonic amide.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hose having a cylindrical flow path through which a fluid flows, particularly to an industrial hose, specifically to a high-pressure hydraulic hose for industrial machinery such as construction machinery and mining machinery, and various hoses for automobiles. [Background technology]

[0002] Industrial hoses used in industrial machinery such as construction machinery and mining machinery are provided with reinforcing layers such as plated wire layers from the viewpoint of pressure resistance, etc. For example, Patent Document 1 discloses an industrial hose having a layer structure in which an inner rubber layer, an organic fiber layer (reinforcing thread layer), a middle rubber layer, a plated wire layer, and an outer rubber layer are laminated in this order to form a cylindrical flow path through which fluids such as hydraulic oil flow.

[0003] Industrial hoses require heat resistance to prevent thermal degradation caused by the passage of high-temperature fluids (such as hydraulic oil at temperatures above 100°C).In addition, industrial hoses require adhesion between the plated wire layer and the middle rubber layer to prevent deterioration of pressure resistance caused by loosening of the plated wire layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-185758 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and has as its object to provide an industrial hose that has excellent heat resistance and excellent adhesion between the plated wire layer and the intermediate rubber layer. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems, and as a result have unexpectedly found that by using at least one of a sulfenamide-based vulcanization accelerator and a thiazole-based vulcanization accelerator, a thiuram-based vulcanization accelerator, and N-phenyl-N-(trichloromethylthio)benzenesulfonamide as constituent materials for the inner rubber layer, and by controlling the total content and mass ratio of the vulcanization accelerators within specific ranges, an industrial hose can be obtained that has excellent heat resistance and excellent adhesion between the plated wire layer and the intermediate rubber layer.

[0007] That is, the gist of the present invention is the following [1] to [8]. [1] An industrial hose having a layer structure in which an inner rubber layer, an organic fiber layer, an intermediate rubber layer, and a plated wire layer are laminated in this order, wherein the inner rubber layer is made of a rubber composition containing components (A) to (D), the total content (B+C) of components (B) and (C) is 0.8 to 2.2 parts by mass per 100 parts by mass of component (A), and the mass ratio (B / C) of component (B) to component (C) is 1.8 to 18. (A) A rubber component containing acrylonitrile butadiene rubber. (B) At least one of a sulfenamide-based vulcanization accelerator and a thiazole-based vulcanization accelerator. (C) Thiuram vulcanization accelerator. (D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide. [2] The industrial hose according to [1], wherein the mass ratio (B / C) of the component (B) to the component (C) is 2 to 10. [3] The industrial hose according to [1] or [2], wherein the component (A) is a rubber component containing acrylonitrile butadiene rubber and butadiene rubber. [4] The industrial hose according to any one of [1] to [3], wherein the acrylonitrile content of the acrylonitrile-butadiene rubber is 18 to 35%. [5] The industrial hose according to any one of [1] to [4], wherein the rubber composition further contains carbon black, and the content of the carbon black is 80 to 150 parts by mass per 100 parts by mass of the component (A). [6] The industrial hose according to any one of [1] to [5], wherein the content of the component (D) is 0.3 to 1.0 parts by mass per 100 parts by mass of the component (A). [7] The industrial hose according to any one of [1] to [6], wherein the inner rubber layer has a thickness of 0.6 to 4.0 mm, and the intermediate rubber layer has a thickness of 0.1 to 1.0 mm. [8] The industrial hose according to any one of [1] to [7], wherein the organic fiber layer is a layer formed by braiding threads made of at least one of polyamide fiber and polyester fiber, and the plated wire layer is a layer formed by braiding brass-plated wire. [Effects of the Invention]

[0008] According to the present invention, an industrial hose can be provided which has excellent heat resistance and excellent adhesion between the plated wire layer and the intermediate rubber layer. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing an example of an industrial hose according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram (graph) showing a reaction force (torque)-time curve obtained in a reaction force (torque) evaluation test of an example. [Figure 3] FIG. 2 is an explanatory diagram (plan view) of a test sample used in an adhesion evaluation test in the examples. [Figure 4] FIG. 4 is an explanatory diagram (a cross-sectional view taken along line AA in FIG. 3) of a test sample used in an adhesion evaluation test in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, an embodiment of the present invention will be described in detail, but the present invention is not limited to this embodiment.

[0011] An industrial hose according to one embodiment of the present invention (hereinafter sometimes referred to as "the hose") is an industrial hose having a layer structure in which an inner rubber layer, an organic fiber layer, an intermediate rubber layer, and a plated wire layer are laminated in this order, and is characterized in that the inner rubber layer is a rubber layer formed using a rubber composition containing components (A) to (D). (A) A rubber component containing acrylonitrile butadiene rubber. (B) At least one of a sulfenamide-based vulcanization accelerator and a thiazole-based vulcanization accelerator. (C) Thiuram vulcanization accelerator. (D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide.

[0012] For industrial hoses, heat resistance is an important property from the viewpoint of preventing thermal deterioration of the inner rubber layer that forms the flow path through which high-temperature fluids flow, while interlayer adhesion between the plated wire layer and the middle rubber layer is an important property from the viewpoint of preventing deterioration of pressure resistance due to loosening of the plated wire layer, etc., and it is desirable to achieve both. From the viewpoint of the heat resistance, a method of increasing heat resistance may be adopted, for example, by vulcanizing the rubber using a thiuram vulcanization accelerator to form many monosulfide bonds and disulfide bonds and suppress re-crosslinking during heat aging. However, such a method is not satisfactory from the viewpoint of adhesion between the plated wire layer and the intermediate rubber layer, and does not achieve both heat resistance and adhesion. On the other hand, when vulcanization is performed using a sulfenamide-based vulcanization accelerator or the like, although the adhesion between the plated wire layer and the intermediate rubber layer is satisfactory, many polysulfide bonds are formed, which makes it easy for re-crosslinking to occur during heat aging, and is therefore unsatisfactory from the standpoint of heat resistance, and it is not possible to achieve both heat resistance and adhesion. As described above, heat resistance and adhesiveness tend to be contradictory properties in industrial hoses, and it is not always easy to achieve both. In the process of searching for a method that can achieve both heat resistance and adhesion, the present inventors focused on the behavior of the intermediate rubber layer and the inner rubber layer during vulcanization in order to analyze the principle or mechanism by which strong adhesion is achieved between the plated wire layer and the intermediate rubber layer. As a result of extensive research from this perspective, the present inventors came up with the idea that a method of controlling the expansion characteristics of the inner rubber layer during vulcanization, thereby imparting to the inner rubber layer the effect of pressing the intermediate rubber layer radially outward, would be effective in improving the adhesion between the plated wire layer and the intermediate rubber layer.

[0013] That is, after various investigations, the inventors have concluded that during the vulcanization process in the manufacturing process of an industrial hose having a layer structure in which an inner rubber layer, an organic fiber layer, an intermediate rubber layer, and a plated wire layer are laminated in this order, the intermediate rubber layer sags into the organic fiber layer, and this phenomenon is the cause of the impairment of adhesion between the outer circumferential surface of the intermediate rubber layer and the inner circumferential surface of the plated wire layer. Specifically, for example, during the vulcanization process in the manufacturing process of an industrial hose, recesses formed on the outer circumferential surface of the organic fiber layer by braiding the threads (recesses having a depth in the layer thickness direction of the organic fiber layer, such as recesses formed in the gaps between the threads that form openings in the mesh fabric that constitutes the organic fiber layer) cause a phenomenon in which part of the intermediate rubber layer sags radially inward in the hose (part of the intermediate rubber layer flows into the recesses), which acts in a direction that causes the outer circumferential surface of the intermediate rubber layer and the inner circumferential surface of the plated wire layer to partially separate, thereby reducing the contact area between the outer circumferential surface of the intermediate rubber layer and the inner circumferential surface of the plated wire layer, for example. Based on these considerations, the present inventors have developed a method for controlling the expansion characteristics of the inner rubber layer during vulcanization, imparting to the inner rubber layer the effect of pressing the intermediate rubber layer radially outward in the hose, and further forming many monosulfide bonds and disulfide bonds, in order to prevent the phenomenon of partial sagging of the intermediate rubber layer in the recesses and the like in the organic fiber layer.

[0014] As a result of extensive experiments, the present inventors have found that, as in the present hose, when the inner rubber layer is formed using a rubber composition containing components (A) to (D), and the total content of components (B) and (C) (B+C) is in a specific range of 0.8 to 2.2 parts by mass per 100 parts by mass of component (A), and the mass ratio of component (B) to component (C) (B / C) is in a specific range of 1.8 to 18, the vulcanization rate can be appropriately suppressed, the expansion of the inner rubber layer can be suitably controlled, and many monosulfide bonds and disulfide bonds can be formed, thereby achieving both heat resistance and adhesiveness. Each layer constituting the present hose will be described in detail below.

[0015] <<Inner rubber layer>> The inner rubber layer is the innermost layer of the hose and forms a tubular flow path through which a fluid flows. The inner rubber layer is formed from a rubber composition. The rubber composition (hereinafter sometimes referred to as the "inner rubber composition") contains at least (A) a rubber component containing acrylonitrile butadiene rubber, (B) at least one of a sulfenamide-based vulcanization accelerator and a thiazole-based vulcanization accelerator, (C) a thiuram-based vulcanization accelerator, and (D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide.

[0016] <(A) Rubber component containing acrylonitrile butadiene rubber> The content of the rubber component including the acrylonitrile butadiene rubber is not limited to the following, but is preferably 30 to 80 mass %, more preferably 32 to 70 mass %, and even more preferably 35 to 55 mass %, relative to the total amount (100 mass %) of the inner rubber composition.

[0017] (Acrylonitrile butadiene rubber (NBR)) The acrylonitrile butadiene rubber (NBR) is a copolymer of acrylonitrile and butadiene, or a hydrogenated copolymer of acrylonitrile and butadiene, which may be used alone or in combination of two or more.

[0018] The acrylonitrile content (AN content) of NBR is not particularly limited, but from the viewpoint of heat resistance and adhesiveness, it is preferably 18 to 35 mass%, more preferably 18 to 30 mass%. The AN content can be measured by the Kjeldahl method in accordance with JIS K6451-2:2016.

[0019] From the viewpoint of adhesiveness, the linear expansion coefficient of NBR is, for example, 2 to 2.5[10 -4 / °C] is preferable. The linear expansion coefficient is more preferably 2.2 to 2.5[10 -4 / °C], and even more preferably 2.3 to 2.5 [10 -4 / °C]. The linear expansion coefficient is the rate of change in length per unit temperature change, and is measured within a predetermined temperature range (>glass transition temperature (Tg)) in accordance with, for example, JIS K7197:2012.

[0020] The Mooney viscosity of NBR is not particularly limited, but is preferably 40-82, more preferably 48-80, and even more preferably 50-78, for example. The Mooney viscosity is measured in accordance with the JIS K6300-1:2013 standard 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.

[0021] The inner rubber composition contains a rubber component containing NBR as a main component. Specifically, the content of NBR is preferably 60% by mass or more, and more preferably 70 to 100% by mass, of the total amount of rubber components contained in the inner rubber composition (total 100% by mass), from the viewpoint of oil resistance. The content of the NBR can be appropriately set within the above range, and may be, for example, 80 to 100 mass%, 85 to 95 mass%, or 88 to 92 mass% relative to the total amount of rubber components contained in the inner rubber composition (total 100 mass%).

[0022] (Other ingredients) The inner rubber composition may contain rubber components other than acrylonitrile butadiene rubber (NBR) (hereinafter, sometimes referred to as "other rubber components"). Examples of other rubber components include, but are not limited to, butadiene rubber (BR), styrene butadiene rubber (SBR), and chloroprene rubber (CR). These may be used alone or in combination of two or more.

[0023] From the viewpoint of oil resistance and adhesion, the content of the other rubber component is, for example, 1 to 20 mass%, and may be 4 to 18 mass%, 6 to 15 mass%, 8 to 12 mass%, etc., relative to the total amount (100 mass%) of the rubber component (A) contained in the inner surface rubber composition.

[0024] The linear expansion coefficient of the other rubber components is, for example, 2.0 to 2.5 [10 -4 / °C] is preferable. The linear expansion coefficient is more preferably 2.1 to 2.5[10 -4 / °C], and even more preferably 2.2 to 2.5 [10 -4 / °C]. By setting the linear expansion coefficient of the other rubber components within the above range, the adhesion between the intermediate rubber layer and the plated wire layer tends to be further improved. The linear expansion coefficient is the rate of change in length per unit temperature change, and is measured within a specified temperature range (>glass transition temperature (Tg)) in accordance with, for example, JIS K7197:2012.

[0025] As the other rubber component, butadiene rubber (BR) is preferred. By using NBR and BR in combination, for example, the inner rubber layer can be suitably expanded, and the adhesion between the intermediate rubber layer and the plated wire layer tends to be further improved, and extrusion moldability and productivity tend to be improved. As the BR, various butadiene rubbers conventionally used as materials for hoses can be used as appropriate, and examples thereof include BR with a high cis content, BR with a low cis content, and BR containing syndiotactic polybutadiene crystals. The microstructure of the BR is not particularly limited, but is preferably, for example, a high cis-butadiene rubber having a cis-1,4 bond content of 90% or more. The cis-1,4 bond content may be 95% or more, or 96% or more. The content of the cis-1,4 is 1 H-NMR, 13 It can be measured using C-NMR, FT-IR, etc.

[0026] The Mooney viscosity of the BR is not particularly limited, but is preferably 30-60, more preferably 30-55, and even more preferably 30-50, for example. The Mooney viscosity is measured in accordance with the JIS K6300-1:2013 standard 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.

[0027] From the viewpoint of adhesion and oil resistance, the total content of butadiene rubber (BR) and acrylonitrile butadiene rubber (NBR) (BR+NBR) is preferably 80 to 100 mass%, more preferably 85 to 100 mass%, relative to the total amount (100 mass%) of rubber component (A) contained in the inner rubber composition. The total content can be set appropriately within the above range, and may be, for example, 90 to 100 mass %, 95 to 100 mass %, 88 to 95 mass %, 88 to 92 mass %, or the like.

[0028] The mass ratio (BR / NBR) of the butadiene rubber (BR) to the acrylonitrile butadiene rubber (NBR) is, for example, preferably 0.01 to 10, more preferably 0.03 to 0.4, and even more preferably 0.05 to 0.25, from the viewpoint of adhesiveness and oil resistance.

[0029] The content of BR is, for example, 1 to 30 mass%, and may be 4 to 20 mass%, 6 to 15 mass%, or 8 to 10 mass%, relative to the total amount (100 mass%) of the rubber component (A) contained in the inner surface rubber composition.

[0030] <(B) At least one of a sulfenamide vulcanization accelerator and a thiazole vulcanization accelerator, and (C) a thiuram vulcanization accelerator> The inner rubber composition contains (B) at least one of a sulfenamide vulcanization accelerator and a thiazole vulcanization accelerator, and (C) a thiuram vulcanization accelerator as vulcanization accelerators. It is important that the total content (B+C) of components (B) and (C) is 0.8 to 2.2 parts by mass per 100 parts by mass of component (A), and that the mass ratio (B / C) of component (B) to component (C) is 1.8 to 18.

[0031] ((B) At least one of sulfenamide vulcanization accelerator and thiazole vulcanization accelerator) Examples of sulfenamide vulcanization accelerators include N-oxydiethylene-2-benzothiazolylsulfenamide (NOBS), N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), Nt-butyl-2-benzothiazoylsulfenamide (BBS), N,N'-dicyclohexyl-2-benzothiazoylsulfenamide, etc. These may be used alone or in combination of two or more.

[0032] Examples of thiazole vulcanization accelerators include dibenzothiazyl disulfide (MBTS), 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole sodium salt (NaMBT), 2-mercaptobenzothiazole zinc salt (ZnMBT), etc. These may be used alone or in combination of two or more.

[0033] As described above, at least one of a sulfenamide vulcanization accelerator and a thiazole vulcanization accelerator is used as component (B). That is, as component (B), only a sulfenamide vulcanization accelerator can be used, only a thiazole vulcanization accelerator can be used, or both a sulfenamide vulcanization accelerator and a thiazole vulcanization accelerator can be used.

[0034] Among these, sulfenamide vulcanization accelerators are preferred from the viewpoint of significantly achieving the effects of the present invention. That is, an industrial hose is preferred in which the inner rubber layer is made of a rubber composition containing components (A) to (D), component (B) is a sulfenamide vulcanization accelerator, the total content (B+C) of components (B) and (C) is 0.8 to 2.2 parts by mass per 100 parts by mass of component (A), and the mass ratio (B / C) of component (B) to component (C) is 1.8 to 18. As the sulfenamide vulcanization accelerator, N-cyclohexyl-2-benzothiazolyl sulfenamide is preferred.

[0035] ((C) Thiuram vulcanization accelerator) Examples of thiuram vulcanization accelerators include tetrabenzylthiuram disulfide (TBzTD), tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), tetrakis(2-ethylhexyl)thiuram disulfide, dipentamethylenethiuram tetrasulfide (DPTT), and dipentamethylenethiuram hexasulfide. These may be used alone or in combination of two or more. Among these, tetramethylthiuram monosulfide (TMTM) is preferably used.

[0036] (Total content of components (B) and (C)) To obtain the effects of the present invention, it is important to control the total content (B+C) of components (B) and (C) within the range of 0.8 to 2.2 parts by mass per 100 parts by mass of component (A). If the total content is outside this range, the inner rubber layer tends to expand insufficiently during vulcanization, making it difficult to achieve both adhesiveness and heat resistance. The total content of components (B) and (C) can be set appropriately within the above range, and may be, for example, 1.0 to 2.1 parts by mass or 1.0 to 2.0 parts by mass per 100 parts by mass of component (A).

[0037] (mass ratio of component (B) to component (C)) From the viewpoint of achieving the effects of the present invention, it is important to control the mass ratio (B / C) of component (B) to component (C) within the range of 1.8 to 18. If the mass ratio is outside the above range, the inner rubber layer tends to expand insufficiently during vulcanization, making it difficult to achieve both adhesiveness and heat resistance. The mass ratio (B / C) of the component (B) to the component (C) can be appropriately set within the above range.

[0038] The content of the component (B) is, for example, preferably 0.4 to 3.0 parts by mass, more preferably 0.6 to 2.5 parts by mass, and even more preferably 0.8 to 2.0 parts by mass, per 100 parts by mass of the component (A). The amount of the component (C) is, for example, preferably 0.1 to 1.2 parts by mass, more preferably 0.2 to 0.8 parts by mass, and even more preferably 0.1 to 0.6 parts by mass per 100 parts by mass of the component (A).

[0039] <(D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide> The inner rubber composition contains (D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide. By using component (D) together with specific proportions of components (B) and (C), the vulcanization rate is moderately suppressed, promoting expansion of the inner rubber layer and forming many monosulfide bonds and disulfide bonds. The content of component (D) is not particularly limited, but from the viewpoint of significantly achieving the effects of the present invention, it is preferably 0.3 to 1.0 part by mass, and more preferably 0.4 to 0.8 part by mass, per 100 parts by mass of component (A).

[0040] <Other ingredients> In addition to the above components (A) to (D), the inner rubber composition may contain optional materials such as vulcanizing agents such as sulfur, vulcanization accelerators other than components (B) and (C), fillers, plasticizers, antioxidants, vulcanization aids, and tackifying resins, as needed, within the range that does not impair the effects of the present invention.

[0041] (sulfur) Examples of sulfur include insoluble sulfur and soluble sulfur. These may be used alone or in combination of two or more. Examples of insoluble sulfur include polymeric sulfur such as μ sulfur, π sulfur, and ω sulfur. Commercially available products include Sanfel (manufactured by Sanshin Chemical Industry Co., Ltd.) and Sanfel EX (manufactured by Sanshin Chemical Industry Co., Ltd.). Examples of soluble sulfur include sulfur having a cyclic structure, such as α sulfur, β sulfur, γ sulfur, and λ sulfur. Commercially available products include Kinkajirushi Fine Sulfur (manufactured by Tsurumi Chemical Industry Co., Ltd.) and Powdered Sulfur S (manufactured by Hosoi Chemical Industry Co., Ltd.). Insoluble sulfur is sulfur that is 90% by mass or more insoluble in carbon disulfide, and soluble sulfur is sulfur that is 99.5% by mass or more soluble in carbon disulfide.

[0042] From the viewpoint of achieving both heat resistance and adhesiveness, the sulfur content is, for example, preferably 0.5 to 2.5 parts by mass, more preferably 0.8 to 2.2 parts by mass, and even more preferably 1 to 1.6 parts by mass, per 100 parts by mass of component (A). If the sulfur content is too high, heat resistance tends to be insufficient.

[0043] (filler) Examples of fillers include carbon black, silica, calcium carbonate, etc. These may be used alone or in combination of two or more.

[0044] The content of the filler is not particularly limited, but is, for example, 80 to 180 parts by mass per 100 parts by mass of the component (A).

[0045] Among the above fillers, carbon black is preferred from the viewpoint of improving durability. Examples of carbon black include various grades of carbon black such as SAF grade, ISAF grade, HAF grade, MAF grade, FEF grade, GPF grade, SRF grade, FT grade, and MT grade. These may be used alone or in combination of two or more types.

[0046] The average particle size of carbon black is not particularly limited, but is preferably 20 to 130 nm, more preferably 20 to 80 nm, and even more preferably 20 to 70 nm. The average particle size of carbon black is a number average particle size, and is measured using a transmission electron microscope.

[0047] The BET specific surface area of carbon black is 10 to 150 m 2 / g is preferable, and 15 to 100m 2 / g, and even more preferably 20 to 80 m 2 / g. The BET specific surface area of carbon black can be measured, for example, by degassing a sample at 200°C for 15 minutes and then using a mixed gas (N: 70%, He: 30%) as the adsorbent gas with a BET specific surface area measuring device (Microdata Corporation, 4232-II).

[0048] The iodine adsorption capacity of carbon black is preferably 10 to 150 mg / g, more preferably 10 to 75 mg / g, and even more preferably 20 to 65 mg / g, and the DBP (dibutyl phthalate) absorption capacity of carbon black is preferably 20 to 180 mL / 100 g, more preferably 20 to 150 mL / 100 g. The iodine adsorption amount of carbon black is a value measured in accordance with JIS K 6217-1:2008 (Method A), and the DBP absorption amount of carbon black is a value measured in accordance with JIS K6217-4:2017.

[0049] The carbon black content is not particularly limited, but is, for example, 80 to 150 parts by mass per 100 parts by mass of component (A). The carbon black content can be appropriately set within the above range, and from the viewpoint of heat resistance, it is, for example, preferably 115 to 150 parts by mass, more preferably 120 to 150 parts by mass.

[0050] (plasticizer) Examples of the plasticizer include ester-based plasticizers, aromatic oils, process oils, etc. These may be used alone or in combination of two or more. Examples of ester-based plasticizers include dioctyl phthalate and bis[2-(2-butoxyethoxy)ethyl] adipate. Examples of aromatic oils include Diana Process AC-12, Diana Process AC-460, and Diana Process AH-16 (all manufactured by Idemitsu Showa Shell Co., Ltd.), JSO Aroma 790 (manufactured by Japan Sun Oil Co., Ltd.), Aromax 1, and Aromax 3 (all manufactured by Fuji Kosan Co., Ltd.). Examples of process oils include naphthenic oil and paraffinic oil.

[0051] The content of the plasticizer is not particularly limited, but is, for example, 5 to 20 parts by mass, preferably 5 to 18 parts by mass, and more preferably 8 to 15 parts by mass, per 100 parts by mass of the component (A).

[0052] (anti-aging agent) Examples of the antioxidant include carbamate-based antioxidants, phenylenediamine-based antioxidants, phenol-based antioxidants, phenylamine-based antioxidants, diphenylamine-based antioxidants, quinoline-based antioxidants, imidazole-based antioxidants, waxes, etc. These may be used alone or in combination of two or more.

[0053] The content of the antioxidant is not particularly limited, but is, for example, 0.5 to 10 parts by mass, 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).

[0054] (vulcanization aid) Examples of the vulcanization aid include zinc oxide, zinc oxide (ZnO), stearic acid, magnesium oxide, etc. These may be used alone or in combination of two or more. The content of the vulcanization aid is not particularly limited, but is, for example, 1 to 12 parts by mass, preferably 2 to 10 parts by mass, and more preferably 3 to 8 parts by mass per 100 parts by mass of the component (A).

[0055] <Preparation of Inner Rubber Composition> The inner rubber composition can be prepared, for example, by appropriately blending the above components (A) to (D) and, if necessary, the above optional components, and kneading them using a kneading machine such as a kneader, roll, or Banbury mixer.

[0056] The inner rubber composition preferably has a predetermined reaction force from the viewpoint of enhancing the adhesion between the plated wire layer and the intermediate rubber layer. Specifically, the reaction force (torque [MPa])-time [s] curve obtained by measuring an unvulcanized sheet-shaped inner rubber composition (a cylindrical shape with a diameter of 29.0 mm and a thickness of 12.5 mm) under conditions of a compression ratio of 5%, 150°C, and 30 minutes is determined to have a bottom torque (T B (lowest torque)) after 30 minutes (T 30 ) ratio (T 30 / T B ) is preferably 1.1 or more, more preferably 1.5 or more, and even more preferably 2 or more. There is no particular upper limit, but it may be 2.5 or less, 3.0 or less, or the like.

[0057] <<Organic fiber layer>> In the present hose, the organic fiber layer is located radially outward of the inner rubber layer and is formed on the outer peripheral surface of the inner rubber layer. The organic fiber layer is also called an underlay reinforcing layer and is a layer interposed between the outer peripheral surface of the inner rubber layer and the inner peripheral surface of the intermediate rubber layer, which will be described later.

[0058] The organic fiber layer is formed of threads made of organic fibers, as in conventional techniques. Examples of organic fibers include, but are not limited to, polyester fibers, polyamide fibers, aramid fibers, vinylon fibers, rayon fibers, PBO (polyparaphenylene benzobisoxazole) fibers, polyketone fibers, and polyarylate fibers. Among these, polyester fibers and polyamide fibers are preferred, and polyamide fibers are more preferred, from the viewpoints of heat resistance and strength.

[0059] The method for forming the organic fiber layer is not particularly limited, but examples thereof include a braiding method in which organic fiber threads are braided using a braider, a spiral method in which organic fiber threads are wound in a spiral shape using a spiral machine, and a method in which a strip-shaped sheet (e.g., mesh fabric) obtained by braiding organic fiber threads is wound in a spiral shape using a winding machine.

[0060] The diameter of the thread made of the organic fiber is not particularly limited, but is, for example, 0.2 to 1.5 mm, and preferably 0.3 to 1.0 mm.

[0061] The braid density of the organic fiber layer is not particularly limited, but is, for example, 20 to 100%, preferably 30 to 90%, and more preferably 45 to 80%. The braid density is the ratio (%) of the area occupied by organic fiber threads to the area of the organic fiber layer, and when there are no gaps between the threads, the braid density is 100%. Specifically, it can be calculated, for example, by the following formula. (Formula) Thread width (diameter) [mm] × number of threads / (2 × π × outer diameter of inner rubber layer [mm] × cosθ [rad]) × 100 (where θ is the thread braiding angle).

[0062] <<Intermediate rubber layer>> In the present hose, the intermediate rubber layer is located radially outward of the organic fiber layer and is formed on the outer peripheral surface of the organic fiber layer. The intermediate rubber layer is a layer interposed between the outer peripheral surface of the organic fiber layer and the inner peripheral surface of the plated wire layer, which will be described later.

[0063] The intermediate rubber layer is formed from a rubber composition (hereinafter sometimes referred to as "intermediate rubber composition"). The intermediate rubber composition is similar to that of conventional technology and is not particularly limited, and can be prepared as appropriate. The intermediate rubber composition contains, for example, a rubber component, a phenolic resin, a vulcanization accelerator, a vulcanizing agent such as sulfur, a filler, a plasticizer, an antioxidant, a vulcanization aid, etc.

[0064] Examples of the rubber component include natural rubber (NR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), isoprene rubber (IR), butadiene rubber (BR), and ethylene propylene diene rubber (EPDM). These may be used alone or in combination of two or more. Among these, NBR is preferred when oil resistance is required, and SBR and NR are preferred when abrasion resistance is required. When NBR is contained as the rubber component, the acrylonitrile content (AN content) of the NBR is not particularly limited, but may be, for example, 33% by mass or less, 28% by mass or less, or 18 to 25% by mass.

[0065] The content of the rubber component is not limited to the following, but is preferably 30 to 80 mass %, more preferably 32 to 70 mass %, and even more preferably 35 to 55 mass %, relative to the total amount (100 mass %) of the intermediate rubber composition.

[0066] The phenolic resin may be any known phenolic resin, and is not particularly limited, but examples thereof include cashew-modified phenolic resins such as cashew-modified phenolic novolac resins, oil-modified phenolic resins, etc. These may be used alone or in combination of two or more. The content of the phenolic resin is preferably 2 to 15 parts by mass, and particularly preferably 2 to 8 parts by mass, per 100 parts by mass of the rubber component.

[0067] The vulcanization accelerator may be any known vulcanization accelerator that is appropriately used, and is not particularly limited. Examples thereof include 2-(4'-morpholinodithio)benzothiazole and N-oxydiethylene-2-benzothiazolylsulfenamide.

[0068] The intermediate rubber composition can be prepared by appropriately blending the above components and kneading them using a kneader, roll, Banbury mixer or other kneading machine.

[0069] The intermediate rubber composition may contain adhesives such as cobalt-based adhesives, melamine-based adhesives, and resorcinol-based adhesives, etc. However, from the viewpoint of heat resistance, the content of the adhesives is preferably less than 0.5% by mass, more preferably less than 0.3% by mass, even more preferably less than 0.1% by mass, and particularly preferably 0% by mass, relative to the total amount (100% by mass) of the intermediate rubber composition.

[0070] <<Plated wire layer>> The plated wire layer is also called a wire reinforcing layer, and is a layer located radially outside the intermediate rubber layer and formed on the outer peripheral surface of the intermediate rubber layer.

[0071] The plated wire layer is similar to that of conventional technology and is not particularly limited and can be formed as appropriate. The plated wire layer is a layer formed from a plated wire, and the plated wire is preferably a steel wire that has been subjected to a plating treatment. Examples of plating treatments include copper plating, zinc plating, brass (copper-zinc alloy) plating, nickel plating, tin plating, and cobalt plating. Among these, brass (copper-zinc alloy) plating is preferred. The copper to zinc content ratio (Cu / Zn) in such brass (copper-zinc alloy) plating is not particularly limited, but is, for example, 70 / 30 to 55 / 45, preferably 70 / 30 to 60 / 40.

[0072] The diameter of the plated wire is usually 0.15 to 1 mm, preferably 0.2 to 0.8 mm.

[0073] The method for forming the plated wire layer is not particularly limited, but includes known braiding methods such as spiral and braid methods, among which the spiral method is preferred.

[0074] <<Outer rubber layer>> In addition to the layers described above, the hose further includes an outer rubber layer, which is positioned radially outward of the plated wire layer and is typically the outermost layer of the hose.

[0075] The outer rubber layer is formed from a rubber composition (hereinafter sometimes referred to as "outer rubber composition"). The outer rubber composition is the same as that of conventional technology and is not particularly limited, and can be prepared as appropriate. The outer rubber composition contains, for example, a rubber component, a vulcanization accelerator, a vulcanizing agent such as sulfur, a filler, a plasticizer, an antioxidant, a vulcanization aid, etc. Examples of the rubber component, from the viewpoint of weather resistance, include chloroprene rubber (CR), styrene butadiene rubber (SBR), ethylene-propylene-diene rubber (EPDM), blended rubber of SBR and EPDM, blended rubber of NBR and EPDM, blended rubber of NBR and polyvinyl chloride (PVC), acrylic rubber (ACM), ethylene acrylate rubber (AEM), chlorinated polyethylene (CM), and chlorosulfonated polyethylene (CSM). These may be used alone or in combination of two or more. Among these, CR is preferred from the viewpoints of weather resistance, cost, and oil resistance.

[0076] The content of the rubber component is not limited to the following, but is preferably 30 to 80 mass %, more preferably 32 to 70 mass %, and even more preferably 35 to 55 mass %, relative to the total amount (100 mass %) of the outer rubber composition.

[0077] The outer rubber composition can be prepared by appropriately blending the above components and kneading them using a kneading machine such as a kneader, roll, or Banbury mixer.

[0078] <<Layer structure of this hose>> The present hose may be any hose having a layer structure in which an inner rubber layer, an organic fiber layer, an intermediate rubber layer, and a plated wire layer are laminated in this order, and may further include, for example, another intermediate rubber layer, another plated wire layer, an outer rubber layer, or other layers. Specific examples include hoses including at least a first intermediate rubber layer, a second intermediate rubber layer, a first plated wire layer, and a second plated wire layer. A preferred embodiment of the present hose includes, but is not limited to, a hose having a layer structure (7 layers) of "inner rubber layer / organic fiber layer / first intermediate rubber layer / first plated wire layer / second intermediate rubber layer / second plated wire layer / outer rubber layer." Furthermore, one example of a suitable embodiment of the present hose is, but is not limited to, a hose having a layer structure (9 layers) of "inner rubber layer / organic fiber layer / first intermediate rubber layer / first plated wire layer / second intermediate rubber layer / second plated wire layer / third intermediate rubber layer / third plated wire layer / outer rubber layer." Furthermore, one example of a suitable embodiment of the present hose is, but is not limited to, a hose having a layer structure (11 layers) of "inner rubber layer / organic fiber layer / first intermediate rubber layer / first plated wire layer / second intermediate rubber layer / second plated wire layer / third intermediate rubber layer / third plated wire layer / fourth intermediate rubber layer / fourth plated wire layer / outer rubber layer."

[0079] The inner diameter of the present hose is not particularly limited, but is usually 5 to 85 mm, preferably 6 to 80 mm, and the outer diameter of the present hose is usually 9 to 100 mm, preferably 10 to 85 mm.

[0080] The thickness of the inner rubber layer is not particularly limited, but is, for example, 0.6 to 4.0 mm, and preferably 1.0 to 2.0 mm. The thickness of the intermediate rubber layer is, for example, 0.1 to 1.0 mm, and preferably 0.2 to 0.6 mm. An excessively thick intermediate rubber layer is undesirable because it tends to cause bulging. The bulging phenomenon occurs when the balance between the relief force of the crimped portion of the inner rubber layer and the resistance force of the uncrimped portion at the base of the hose connector (the end where the hose is inserted) becomes greater due to a change in the rubber properties caused by heat, resulting in the inner rubber layer peeling off from the organic fiber layer and the inner rubber in the peeled portion undergoing thermal flow and breaking.

[0081] The ratio of the thickness of the inner rubber layer to the thickness of the intermediate rubber layer (thickness of inner rubber layer / thickness of intermediate rubber layer) is not particularly limited, but is, for example, 2 to 20, and preferably 3 to 12. When the ratio is within the above range, the intermediate rubber layer does not inhibit the expansion of the inner rubber layer during vulcanization, and the adhesion between the intermediate rubber layer and the plated wire layer can be further improved.

[0082] The thickness of the organic fiber layer is not particularly limited, but is, for example, 0.2 to 1.5 mm, and preferably 0.3 to 0.5 mm. The thickness of the plated wire layer is not particularly limited, but is, for example, 0.2 to 1.0 mm, and preferably 0.3 to 0.8 mm. The thickness of the outer rubber layer is not particularly limited, but is, for example, 0.5 to 2.5 mm, and preferably 0.8 to 2 mm.

[0083] One embodiment of the present hose will be described with reference to Figure 1. However, the present invention is not limited to the structure shown in Figure 1. Figure 1 is a schematic diagram showing the cross section of a hose having a five-layer structure in which an organic fiber layer 2 is formed on the outer peripheral surface of an inner rubber layer 1, an intermediate rubber layer 3 is formed on the outer peripheral surface of the organic fiber layer 2, a plated wire layer 4 is formed on the outer peripheral surface of the intermediate rubber layer 3, and an outer rubber layer 5 is formed on the outer peripheral surface of the plated wire layer 4.

[0084] In the present hose, examples of an embodiment in which the intermediate rubber layer 3 and the plated wire layer 4 are alternately repeated as a layer structure include "inner rubber layer 1 / organic fiber layer 2 / intermediate rubber layer 3 / plated wire layer 4 / intermediate rubber layer 3 / plated wire layer 4 / outer rubber layer 5" and "inner rubber layer 1 / organic fiber layer 2 / intermediate rubber layer 3 / plated wire layer 4 / intermediate rubber layer 3 / plated wire layer 4 / intermediate rubber layer 3 / plated wire layer 4 / outer rubber layer 5."

[0085] <<Manufacturing method>> An example of a manufacturing method for this hose will be described using an embodiment of the present invention shown in Fig. 1. First, an inner rubber composition is extruded onto a mandrel using an extrusion molding machine to form inner rubber layer 1. Next, a strip-shaped sheet made of braided organic fiber yarns (e.g., polyamide fiber yarns) is spirally wound around the outer surface of inner rubber layer 1 using a winding machine to form organic fiber layer 2. Next, an intermediate rubber composition is extruded onto the outer surface of organic fiber layer 2 to form intermediate rubber layer 3. Next, a brass-plated wire is spirally braided onto the outer surface of intermediate rubber layer 3 using a braiding machine to form plated wire layer 4. Next, an outer rubber composition is extruded onto the outer surface of plated wire layer 4 to form outer rubber layer 5. Next, polyamide canvas is spirally braided onto the outer surface of the outer rubber layer 5 using a braiding machine, and after steam vulcanizing this laminate (e.g., at 150°C for 60 minutes), the polyamide canvas is removed to produce a hose with a five-layer structure.

[0086] <<Application>> This hose is used as an industrial hose such as a high-pressure hydraulic hose for construction machinery, and various hoses for automobiles (e.g., oil hoses, fuel hoses, air hoses, water hoses, etc.). [Example]

[0087] Next, examples will be described together with comparative examples, but the present invention is not limited to these examples.

[0088] <<Inner rubber layer>> The following materials were prepared as the rubber composition for forming the inner rubber layer.

[0089] <(A) Rubber component> NBR1 (acrylonitrile butadiene rubber, Nipol DN302, manufactured by Zeon Corporation, AN content: 28% by mass, Mooney viscosity: 62.5 (ML 1+4 , 100℃) NBR2 (acrylonitrile butadiene rubber, Nipol DN401, manufactured by Zeon Corporation, AN content: 18% by mass, Mooney viscosity: 77.5 (ML 1+4 , 100℃) NBR3 (acrylonitrile butadiene rubber, Nipol DN3350, manufactured by Zeon Corporation, AN content: 33% by mass, Mooney viscosity: 50 (ML 1+4 , 100℃) BR (butadiene rubber, Ubepol BR-150, manufactured by Ube Industries, Mooney viscosity: 43 (ML 1+4 , 100℃)

[0090] <(B) Sulfenamide-based vulcanization accelerators, thiazole-based vulcanization accelerators> N-Cyclohexyl-2-benzothiazole sulfenamide (Suncerer CM, manufactured by Sanshin Chemical Industry Co., Ltd.) Dibenzothiazyl disulfide (Suncerer DM, manufactured by Sanshin Chemical Industry Co., Ltd.)

[0091] <(C) Thiuram vulcanization accelerator> Tetramethylthiuram monosulfide (Suncerer TS, manufactured by Sanshin Chemical Industry Co., Ltd.)

[0092] <(D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide> Bull current E / C, manufactured by LANXESS

[0093] <Filler> Carbon black (Seast S, manufactured by Tokai Carbon Co., Ltd., nitrogen adsorption specific surface area: 27 m 2 / g, iodine adsorption: 26mg / g, DBP absorption: 68mL / 100g)

[0094] <Sulfur> Sulfur (Kinka brand finely powdered sulfur, manufactured by Tsurumi Chemical Industry Co., Ltd.)

[0095] <Anti-aging agent> Phenylamine antioxidant (2,2,4-trimethyl-1,2-dihydroquinoline, Nonflex RD, manufactured by Seiko Chemical Co., Ltd.)

[0096] <Plasticizer> Ester-based plasticizer (dioctyl phthalate (DOP, manufactured by Taoka Chemical Co., Ltd.))

[0097] <Processing aids> Stearic acid (Lunacc S-70V, manufactured by Kao Corporation) Zinc oxide (Zinc oxide type 2, manufactured by Sakai Chemical Industry Co., Ltd.)

[0098] The above components were blended in the proportions shown in Table 1 and kneaded using a kneader to prepare each unvulcanized inner surface rubber composition.

[0099] <Heat resistance evaluation test> The inner rubber composition obtained above was press-vulcanized at 150°C for 30 minutes to prepare cylindrical vulcanized rubber samples (diameter 29.0 mm, height 12.5 mm). Compression set of these vulcanized rubber samples was measured at 120°C for 72 hours at a compression ratio of 25% in accordance with JIS K 6262:2013, and evaluated according to the following criteria. The results are shown in Table 1. (Evaluation criteria) ◎: Less than 30% 〇: 30% or more but less than 40% ×: 40% or more

[0100] <Reaction force (torque) evaluation test> An unvulcanized cylindrical rubber sheet (diameter 29.0 mm, thickness 12.5 mm) was prepared using the inner rubber composition obtained above. It was compressed in the thickness direction (compression rate 5%) and heat-treated at 150°C for 30 minutes, and the reaction force (torque) was measured. The bottom torque (T B ) after 30 minutes (T 30 ) ratio (T 30 / T B ) was determined and evaluated according to the following criteria. This ratio is an index showing that the inner rubber layer expands within a suitable range and contributes to improving adhesion. As a result of the above test, the inner surface rubber composition of Example 2 was evaluated as "Excellent" (see FIG. 2). (Evaluation criteria) ◎: 1.5 or higher 〇: 1.1 or more and less than 1.5 ×: Less than 1.1

[0101] Next, the following test samples were prepared to evaluate adhesiveness.

[0102] <<How to prepare test samples>> An unvulcanized inner surface rubber sheet 1s (100 mm long x 100 mm wide, 2.5 mm thick) was prepared using the inner surface rubber composition.

[0103] Nylon mesh sheet 2s (length 100 mm x width 100 mm, thickness 0.5 mm) was produced using a nylon mesh sheet (wire diameter: 0.5 mm, thickness: 0.5 mm, opening (distance between threads): 1.2 mm, opening area (void ratio): 50%).

[0104] An unvulcanized intermediate rubber sheet 3s (100 mm long x 100 mm wide, 0.40 mm thick) was prepared using the intermediate rubber composition below. (Intermediate rubber composition) An intermediate rubber composition was prepared by kneading 100 parts by mass of NBR (Nipol DN401 manufactured by Nippon Zeon Co., Ltd.), 8 parts by mass of a phenolic resin (Sumilite Resin PR-12686 manufactured by Sumitomo Bakelite Co., Ltd.), 1 part by mass of a thiazole vulcanization accelerator (Noccela MDB manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), 0.5 parts by mass of a guanidine vulcanization accelerator (Noccela D manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), 5 parts by mass of zinc oxide (zinc oxide type 2, manufactured by Mitsui Mining and Smelting Co., Ltd.), 1 part by mass of stearic acid (Lunac S30 manufactured by Kao Corporation), 80 parts by mass of carbon black (Seest SO manufactured by Tokai Carbon Co., Ltd.), 15 parts by mass of a plasticizer (Adeka Cizer RS-107 manufactured by ADEKA Corporation), and 2 parts by mass of sulfur (Karuizawa Seirensho Co., Ltd.) using a kneader according to a conventional method.

[0105] Brass plate pieces 4a and 4b (length 25 mm, width 100 mm, thickness 2.5 mm) having a substantially rectangular shape in plan view were produced using a brass plate (CP2801, thickness 0.25 mm).

[0106] A test sample was prepared by laminating the nylon mesh sheet 2s on the inner rubber sheet 1s prepared above, laminating an intermediate rubber sheet 3s on the nylon mesh sheet 2s, and laminating brass plate pieces 4a and 4b on the intermediate rubber sheet 3s (see Figs. 3 and 4). Fig. 4 is a cross-sectional view taken along line AA in Fig. 3. In addition, in order to conduct the peel test described below, the test sample has a zipper film (90 cm long, 30 cm wide) laminated between the intermediate rubber sheet 3s and the brass plate pieces 4a and 4b (the zipper film is not shown in the figure).

[0107] <Adhesion evaluation test> The test sample was press-vulcanized for 30 minutes under conditions of a surface pressure of 2.0 MPa, 150° C. Using the vulcanized test sample, the adhesion between the intermediate rubber sheet 3s and the brass plate pieces 4a and 4b was evaluated. Specifically, the chucking film interposed between the intermediate rubber sheet 3s and the brass plate pieces 4a, 4b was fastened, and a T-peel test (peel speed 50 mm / min) was performed in accordance with JIS K 6256-1:2013. The adhesion between the intermediate rubber layer and the plated wire layer was evaluated based on the adhesion rate of the intermediate rubber sheet 3s to the brass plate pieces 4a, 4b after peeling. Note that a higher adhesion rate indicates better adhesion between the two. (Evaluation criteria) ◎: Adhesion rate of the intermediate rubber sheet on the brass plate piece is 90% or more ○: Adhesion rate of the intermediate rubber sheet on the brass plate piece is less than 90% and more than 80% ×: The adhesion rate of the intermediate rubber sheet on the brass plate piece is less than 80%

[0108] [Table 1]

[0109] The results in Table 1 above show that an industrial hose in which the inner rubber layer is made of a rubber composition containing components (B) to (D) together with component (A), the total content of components (B) and (C) (B+C) is 0.8 to 2.2 parts by mass per 100 parts by mass of component (A), and the mass ratio of component (B) to component (C) (B / C) is 1.8 to 18 will have excellent heat resistance and excellent adhesion between the plated wire layer and the middle rubber layer.

[0110] In contrast, it is clear that the heat resistance is insufficient when the rubber composition forming the inner rubber layer does not contain component (C), as in Comparative Example 1. It is also clear that the adhesion is insufficient when the rubber composition forming the inner rubber layer does not contain component (B), as in Comparative Example 2. It is also clear that the heat resistance is insufficient when the rubber composition forming the inner rubber layer does not contain component (D), as in Comparative Example 3. Furthermore, as in Comparative Example 4, when the rubber composition forming the inner rubber layer contains components (B) to (D), but the total content (B+C) of components (B) and (C) is high, the adhesion is found to be insufficient. Furthermore, as in Comparative Example 5, when the rubber composition forming the inner rubber layer contains components (B) to (D) but the mass ratio (B / C) of component (B) to component (C) is small, the adhesion is found to be insufficient. Furthermore, as in Comparative Example 6, when the rubber composition forming the inner rubber layer contains components (B) to (D), but the total content (B+C) of components (B) and (C) is high and the mass ratio (B / C) of component (B) to component (C) is small, adhesion is also insufficient.

[0111] <<Hose production>> First, the inner rubber composition according to the above example was extruded onto a mandrel using an extrusion molding machine to form an inner rubber layer. Next, a strip-shaped sheet (e.g., the nylon mesh sheet described above) made of braided organic fiber threads was spirally wound around the outer surface of the inner rubber layer using a winding machine to form an organic fiber layer. Subsequently, the intermediate rubber composition used in the above test was extruded onto the outer surface of the organic fiber layer to form an intermediate rubber layer. Next, a plated wire layer was formed by spirally braiding a brass-plated wire (0.4 mm in diameter) around the outer surface of the intermediate rubber layer. This process was repeated to form an inner rubber layer / organic fiber layer / intermediate rubber layer / plated wire layer / intermediate rubber layer / plated wire layer / intermediate rubber layer / plated wire layer. The following outer rubber composition was then extruded onto the outer surface of the plated wire layer to form an outer rubber layer. Furthermore, a polyamide canvas was spirally wound around the outer surface of the outer rubber layer. Finally, this laminate was steam vulcanized at 150°C for 60 minutes, and then the polyamide canvas was removed to prepare an 11-layer high-pressure hydraulic hose (inner diameter: 19 mm).

[0112] (Outer rubber composition) 100 parts by mass of CR (Denka Chloroprene M-40, non-sulfur modified type, manufactured by Denki Kagaku Kogyo Co., Ltd.), 50 parts by mass of carbon black (Seast SO, manufactured by Tokai Carbon Co., Ltd.), 25 parts by mass of calcium carbonate (Whiten SB, manufactured by Shiraishi Calcium Co., Ltd.), 20 parts by mass of plasticizer (rapeseed oil, manufactured by Ajinomoto Co., Inc.), 1 part by mass of stearic acid (Lunac S30, manufactured by Kao Corporation), 10 parts by mass of zinc oxide (zinc oxide type 2, manufactured by Mitsui Kinzoku Co., Ltd.), 5 parts by mass of acid acceptor (Kyowa Mag #150, manufactured by Kyowa Chemical Industry Co., Ltd.), 5 parts by mass of acid acceptor [Mg 4.5 Al2(OH) 13 The rubber composition was prepared by blending 5 parts by mass of a rubber composition containing 5% CO3·3.5H2O (DHT-4A, manufactured by Kyowa Chemical Industry Co., Ltd.), 1 part by mass of an antioxidant (Ozonone 3C, manufactured by Seiko Chemical Co., Ltd.), 0.5 parts by mass of a vulcanizing agent (Suncerer 22C, manufactured by Sanshin Chemical Industry Co., Ltd.), 0.5 parts by mass of a vulcanizing agent (Nocrac MB, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), and 0.5 parts by mass of a vulcanization accelerator (Suncerer TT, manufactured by Sanshin Chemical Industry Co., Ltd.), and kneading the mixture in a kneader.

[0113] The brass-plated wire used was a brass-plated wire manufactured by Tokusen Co., Ltd. (electroplated, plating composition: Cu / Zn=65 / 35 mass %, plating weight: 4 g / kg).

[0114] Although a nylon mesh sheet is used as the organic fiber layer in the above example, the present invention is not limited to this, and the type of organic fiber, the opening area (void ratio), etc. can be appropriately selected. For example, the opening area (void ratio) of the organic fiber layer is preferably 30 to 90%, more preferably 40 to 80%, and even more preferably 40 to 70%. The opening area (%) is a standard value used in the technical field, and is called "OP 2 / (OP+wire diameter) 2 " (OP = distance between threads). [Industrial Applicability]

[0115] The industrial hose of the present invention is useful as an industrial hose with a plated wire layer (reinforcing layer), such as a high-pressure hydraulic hose for construction machinery, mining machinery, and industrial vehicles (forklifts, automated guided vehicles, etc.), or an engine oil hose for automobiles. [Explanation of symbols]

[0116] 1. Inner rubber layer 2. Organic fiber layer 3. Middle rubber layer 4. Plated wire layer 5. Outer rubber layer

Claims

1. An industrial hose including a layer structure in which an inner rubber layer, an organic fiber layer, an intermediate rubber layer, and a plated wire layer are laminated in this order, wherein the inner rubber layer is made of a rubber composition containing components (A) to (D), the total content (B+C) of components (B) and (C) is 0.8 to 2.2 parts by mass per 100 parts by mass of component (A), and the mass ratio (B / C) of component (B) to component (C) is 1.8 to 18. (A) A rubber component containing acrylonitrile butadiene rubber. (B) At least one of a sulfenamide vulcanization accelerator and a thiazole vulcanization accelerator. (C) Thiuram vulcanization accelerator. (D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide.

2. 2. The industrial hose according to claim 1, wherein the mass ratio (B / C) of the component (B) to the component (C) is 2 to 10.

3. 3. The industrial hose according to claim 1, wherein the component (A) is a rubber component containing acrylonitrile-butadiene rubber and butadiene rubber.

4. 3. The industrial hose according to claim 1, wherein the acrylonitrile-butadiene rubber has an acrylonitrile content of 18 to 35%.

5. 3. The industrial hose according to claim 1, wherein the rubber composition further contains carbon black, and the content of the carbon black is 80 to 150 parts by mass per 100 parts by mass of the component (A).

6. 3. The industrial hose according to claim 1, wherein the content of the component (D) is 0.3 to 1.0 part by mass per 100 parts by mass of the component (A).

7. 3. The industrial hose according to claim 1, wherein the inner rubber layer has a thickness of 0.6 to 4.0 mm, and the intermediate rubber layer has a thickness of 0.1 to 1.0 mm.

8. 3. The industrial hose according to claim 1, wherein the organic fiber layer is a layer formed by braiding threads made of at least one of polyamide fiber and polyester fiber, and the plated wire layer is a layer formed by braiding brass-plated wire.

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