Industrial hose

Abstract

The present invention provides an industrial hose which is excellent in terms of heat resistance and adhesion between a plated wire layer 4 and an intermediate rubber layer 3.　This industrial hose includes a layer structure in which an inner surface 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 surface rubber layer 1 is formed of a rubber composition that contains components (A)-(D). The total content (B + C) of the component (B) and the component (C) is 0.8-2.2 parts by mass with respect to 100 parts by mass of the component (A), and the mass ratio (B / C) of the component (B) to the component (C) is 1.8-18. (A) a rubber component which contains an 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.

Description

Industrial Hose

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

[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), an intermediate 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 (e.g., hydraulic oil at 100°C or higher), and also require adhesion between the plated wire layer and the intermediate rubber layer to prevent deterioration of pressure resistance caused by loosening of the plated wire layer.

[0004] Japanese Patent Application Laid-Open No. 2014-185758

[0005] The present invention has been made in view of the above circumstances, and provides an industrial hose that has excellent heat resistance and excellent adhesion between the plated wire layer and the intermediate rubber layer.

[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 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 including 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. (D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide. [2] The industrial hose according to [1], wherein the mass ratio (B / C) of the (B) component to the (C) component is 2 to 10. [3] The industrial hose according to [1] or [2], wherein the (A) component 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 (A) component. [6] The industrial hose according to any one of [1] to [5], wherein the content of the (D) component is 0.3 to 1.0 part by mass per 100 parts by mass of the (A) component. [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.

[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.

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

[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") has a layered 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 vulcanization accelerator and a thiazole vulcanization accelerator; (C) a thiuram vulcanization accelerator; and (D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide.

[0012] For industrial hoses, heat resistance is an important characteristic from the viewpoint of suppressing thermal degradation of the inner rubber layer that forms the flow path through which high-temperature fluids flow. Meanwhile, interlayer adhesion between the plated wire layer and the intermediate rubber layer is an important characteristic from the viewpoint of suppressing deterioration of pressure resistance due to loosening of the plated wire layer, and it is desirable to achieve both. From the viewpoint of heat resistance, for example, a method of improving heat resistance by vulcanizing using a thiuram-based vulcanization accelerator to form many monosulfide bonds and disulfide bonds and suppress re-crosslinking during heat aging is sometimes adopted. 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, although the adhesion between the plated wire layer and the intermediate rubber layer is satisfactory, the formation of many polysulfide bonds makes re-crosslinking prone to occur during heat aging, which is unsatisfactory from the viewpoint of heat resistance, and therefore does not achieve both heat resistance and adhesion. As such, heat resistance and adhesion tend to be contradictory properties in industrial hoses, and achieving both is not always easy. In the process of searching for a method that can achieve both heat resistance and adhesion, the present inventor 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. After extensive research from this perspective, the present inventor 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 inferred 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 yarns (recesses having a depth in the layer thickness direction of the organic fiber layer, such as recesses formed in gaps between the yarns that form openings in the mesh fabric of the organic fiber layer) cause a phenomenon in which part of the intermediate rubber layer sags radially inward in the hose (a phenomenon in which 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 experimentation, 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), the total content of components (B) and (C) (B+C) is within 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 within a specific range of 1.8 to 18, the vulcanization rate is appropriately suppressed, the expansion of the inner rubber layer can be suitably controlled, and numerous monosulfide bonds and disulfide bonds can be formed, thereby achieving both heat resistance and adhesiveness. Each layer constituting the present hose is 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 containing acrylonitrile-butadiene rubber is not limited to the following, but is preferably 30 to 80% by mass, more preferably 32 to 70% by mass, and even more preferably 35 to 55% by mass, relative to the total amount (100% by mass) of the inner surface 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. These 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] 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, for example, 40 to 82, more preferably 48 to 80, and even more preferably 50 to 78. The Mooney viscosity is measured in accordance with the JIS K6300-1:2013 standard using an L-shaped rotor under conditions of a preheating time of 1 minute, a 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, based on the total amount of rubber components contained in the inner rubber composition (100% by mass in total), from the viewpoint of oil resistance. The content of NBR can be appropriately set within the above range, and may be, for example, 80 to 100% by mass, 85 to 95% by mass, or 88 to 92% by mass, based on the total amount of rubber components contained in the inner rubber composition (100% by mass in total).

[0022] (Other Components) 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), chloroprene rubber (CR), etc. 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(s) is, for example, 1 to 20 mass %, and may also be 4 to 18 mass %, 6 to 15 mass %, or 8 to 12 mass %, 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] from the viewpoint of suitably controlling the expansion of the inner rubber layer during vulcanization. -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)), for example, in accordance with JIS K7197:2012.

[0025] As the other rubber component, butadiene rubber (BR) is preferred. The combined use of NBR and BR, for example, tends to favorably expand the inner rubber layer, further improve the adhesion between the intermediate rubber layer and the plated wire layer, and also improve extrusion moldability and productivity. As the BR, various butadiene rubbers conventionally used as hose materials can be used as appropriate, including, for example, 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 a high cis-butadiene rubber having a cis-1,4 bond content of 90% or more is preferred. The cis-1,4 bond content may be 95% or more, or even 96% or more. The cis-1,4 content is, 1 H-NMR, 13 Measurement can be performed using C-NMR, FT-IR, etc.

[0026] The Mooney viscosity of the BR is not particularly limited, but is preferably, for example, 30 to 60, more preferably 30 to 55, and even more preferably 30 to 50. The Mooney viscosity is measured in accordance with the JIS K6300-1:2013 standard using an L-shaped rotor under conditions of a preheating time of 1 minute, a 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% by mass, more preferably 85 to 100% by mass, relative to the total amount (100% by mass) of rubber component (A) contained in the inner rubber composition. The total content can be appropriately set within the above range, and may be, for example, 90 to 100% by mass, 95 to 100% by mass, 88 to 95% by mass, or 88 to 92% by mass.

[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 viewpoints of adhesiveness and oil resistance.

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

[0030] <(B) At Least One of Sulfenamide-Based Vulcanization Accelerator and Thiazole-Based Vulcanization Accelerator, and (C) Thiuram-Based Vulcanization Accelerator> The inner rubber composition contains, as vulcanization accelerators, (B) at least one of a sulfenamide-based vulcanization accelerator and a thiazole-based vulcanization accelerator, and (C) a thiuram-based vulcanization accelerator. 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), N-t-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-based 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-based 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. Furthermore, N-cyclohexyl-2-benzothiazolyl sulfenamide is preferred as the sulfenamide-based vulcanization accelerator.

[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), dipentamethylenethiuram hexasulfide, and the like. These may be used alone or in combination of two or more. Of these, tetramethylthiuram monosulfide (TMTM) is preferably used.

[0036] (Total Content of Component (B) and Component (C)) From the viewpoint of achieving the effects of the present invention, it is important to control the total content of component (B) and component (C) (B+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 the above range, it becomes difficult to achieve both adhesion and heat resistance, for example, as the inner rubber layer tends to expand insufficiently during vulcanization. The total content of component (B) and component (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, it becomes difficult to achieve both adhesiveness and heat resistance, for example, as the inner rubber layer tends to expand insufficiently during vulcanization. The mass ratio (B / C) of component (B) to component (C) can be set appropriately within the above range, and is, for example, preferably 2 to 12, more preferably 2 to 10.

[0038] The content of 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 component (A). The content of 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 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 can be appropriately suppressed to promote expansion of the inner rubber layer, and a large number of monosulfide bonds and disulfide bonds can be formed. 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, more preferably 0.4 to 0.8 part by mass, per 100 parts by mass of component (A).

[0040] <Other Components> In addition to the components (A) to (D), the inner rubber composition may contain optional materials such as vulcanizing agents such as sulfur, vulcanization accelerators other than the 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 insoluble in carbon disulfide at a rate of 90% by mass or more. Soluble sulfur is sulfur that is soluble in carbon disulfide at a rate of 99.5% by mass or more.

[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 the filler 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 preferred, and 15 to 100m 2 / g, and even more preferably 20 to 80 m 2 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. 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 capacity of carbon black is a value measured in accordance with JIS K6217-1:2008 (Method A), and the DBP absorption capacity of carbon black is a value measured in accordance with JIS K6217-4:2017.

[0049] The amount of carbon black is not particularly limited, but is, for example, 80 to 150 parts by mass per 100 parts by mass of component (A). The amount of carbon black 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, and more preferably 120 to 150 parts by mass.

[0050] (Plasticizer) Examples of plasticizers include ester-based plasticizers, aromatic oils, and process oils. 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 oils and paraffinic oils.

[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 component (A).

[0052] (Antiaging Agent) Examples of the antiaging agent include carbamate-based antiaging agents, phenylenediamine-based antiaging agents, phenol-based antiaging agents, phenylamine-based antiaging agents, diphenylamine-based antiaging agents, quinoline-based antiaging agents, imidazole-based antiaging agents, 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 the component (A).

[0054] (Vulcanization aid) Examples of vulcanization aids 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 component (A).

[0055] <Preparation of Inner Rubber Composition> The inner rubber composition can be prepared, for example, by appropriately blending the above-mentioned components (A) to (D) and, if necessary, the above-mentioned optional components, and kneading them using a kneading machine such as a kneader, a roll, or a 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]) vs. time [s] curve obtained by measuring an unvulcanized sheet-shaped inner rubber composition (cylindrical, 29.0 mm in diameter and 12.5 mm in thickness) under conditions of a compression ratio of 5%, 150°C, and 30 minutes is determined to be the 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. The upper limit is not particularly limited, but 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 the prior art. The organic fibers are not particularly limited, but examples thereof include 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 organic fiber thread 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 the braid density is 100% when there are zero gaps between the threads. 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] × cos θ [rad]) × 100 (where θ is the braid angle of the threads).

[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 the "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 included 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. Examples include cashew-modified phenolic resins such as cashew-modified phenolic novolac resins, and oil-modified phenolic resins. 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 used appropriately, and is not particularly limited. Examples 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, which is also called a wire reinforcing layer, is located radially outside the intermediate rubber layer and is a layer 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. Of 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 present hose further comprises an outer rubber layer. The outer rubber layer is located radially outward of the plated wire layer and is usually the outermost layer of the present hose.

[0075] The outer rubber layer is formed from a rubber composition (hereinafter sometimes referred to as the "outer rubber composition"). The outer rubber composition is similar to 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, and the like. From the viewpoint of weather resistance, examples of the rubber component include chloroprene rubber (CR), styrene butadiene rubber (SBR), ethylene-propylene-diene rubber (EPDM), a blend rubber of SBR and EPDM, a blend rubber of NBR and EPDM, a blend 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 kneader, roll, Banbury mixer or other kneading machine.

[0078] <<Layer Structure of the Present Hose, etc.>> 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. For example, the hose may further include other intermediate rubber layers, other plated wire layers, an outer rubber layer, or other layers. Specifically, the present hose may include 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." Another preferred embodiment of the present hose includes, 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 preferred 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 hose is not particularly limited, but is usually 5 to 85 mm, preferably 6 to 80 mm, and the outer diameter of the 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, preferably 1.0 to 2.0 mm. The thickness of the intermediate rubber layer is, for example, 0.1 to 1.0 mm, preferably 0.2 to 0.6 mm. An excessively thick intermediate rubber layer is undesirable because it tends to cause bulging. Note that the bulging refers to a phenomenon in which 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 rupture.

[0081] The ratio of the thickness of the inner rubber layer to the thickness of the intermediate rubber layer (thickness of the inner rubber layer / thickness of the 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 layered 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 Figure 1 as an example. 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 around 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, a polyamide canvas is spirally braided around the outer surface of outer rubber layer 5 using a braiding machine. The resulting laminate is steam-vulcanized (e.g., at 150°C for 60 minutes), and the polyamide canvas is removed to produce a five-layer hose.

[0086] <<Applications>> 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.).

[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 rubber compositions for forming the inner rubber layer.

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

[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-based vulcanization accelerator> Tetramethylthiuram monosulfide (Suncerer TS, manufactured by Sanshin Chemical Industry Co., Ltd.)

[0092] <(D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide> Bullcurrent 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: 26 mg / g, DBP absorption: 68 mL / 100 g)

[0094] <Vulcanizing agent> Sulfur (Kinka brand fine powder sulfur, manufactured by Tsurumi Chemical Industry Co., Ltd.)

[0095] <Anti-aging agent> Phenylamine-based anti-aging agent (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 a cylindrical vulcanized rubber sample (diameter 29.0 mm, height 12.5 mm). Using this vulcanized rubber sample, compression set was measured at 120°C, for 72 hours, and at a compression rate of 25% in accordance with JIS K6262:2013, and evaluated according to the following criteria. The results are shown in Table 1. (Evaluation criteria) ◎ (excellent): less than 30% ◯ (good): 30% or more but less than 40% × (poor): 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 surface rubber composition obtained above. The sheet was compressed in the thickness direction (compression rate 5%) and subjected to heat treatment at 150°C for 30 minutes to measure the reaction force (torque). 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 rubber composition of Example 2 was evaluated as "◎" (see Figure 2). (Evaluation criteria) ◎ (excellent): 1.5 or more ◯ (good): 1.1 or more and less than 1.5 × (poor): Less than 1.1

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

[0102] <<Method of Preparing Test Samples>> Using the above inner surface rubber composition, an unvulcanized inner surface rubber sheet 1s (100 mm length x 100 mm width, 2.5 mm thickness) was prepared.

[0103] A 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 described below. (Intermediate rubber composition) 100 parts by mass of NBR (manufactured by Nippon Zeon Co., Ltd., Nipol DN401), 8 parts by mass of a phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., SUMILITE RESIN PR-12686), 1 part by mass of a thiazole-based vulcanization accelerator (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Noccela MDB), 0.5 parts by mass of a guanidine-based vulcanization accelerator (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., Noccela D), 5 parts by mass of zinc oxide (zinc oxide type 2, manufactured by Mitsui Mining & Smelting Co., Ltd.), 1 part by mass of stearic acid (manufactured by Kao Corporation, Lunac S30), 80 parts by mass of carbon black (manufactured by Tokai Carbon Co., Ltd., Seest SO), 15 parts by mass of a plasticizer (manufactured by ADEKA Corporation, Adeka Cizer RS-107), and 2 parts by mass of sulfur (manufactured by Karuizawa Seirensho Co., Ltd.) were kneaded using a kneader according to a conventional method to prepare an intermediate rubber composition.

[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 A-A in FIG. 3. In addition, the test sample was prepared by laminating a zipper film (90 cm long, 30 cm wide) between the intermediate rubber sheet 3s and the brass plate pieces 4a and 4b in order to conduct a peel test, which will be described later (the zipper film is not shown).

[0107] <Adhesion Evaluation Test> The test sample was press-vulcanized under conditions of a surface pressure of 2.0 MPa, 150°C, and 30 minutes. The vulcanized test sample was used to evaluate the adhesion between the intermediate rubber sheet 3s and the brass plate pieces 4a and 4b. Specifically, the chuck film interposed between the intermediate rubber sheet 3s and the brass plate pieces 4a and 4b was chucked, and a T-peel test was performed (peel rate 50 mm / min) in accordance with JIS K6256-1:2013. 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 and 4b after peeling. Note that a higher adhesion rate indicates better adhesion between the two. (Evaluation criteria) ◎ (excellent): Adhesion rate of intermediate rubber sheet on brass plate piece is 90% or more ○ (good): Adhesion rate of intermediate rubber sheet on brass plate piece is 80% or more but less than 90% × (poor): Adhesion rate of intermediate rubber sheet on brass plate piece is less than 80%

[0108]

[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, has excellent heat resistance and excellent adhesion between the plated wire layer and the intermediate rubber layer.

[0110] In contrast, when the rubber composition forming the inner rubber layer does not contain the (C) component, as in Comparative Example 1, the heat resistance is insufficient. Also, when the rubber composition forming the inner rubber layer does not contain the (B) component, as in Comparative Example 2, the adhesion is insufficient. Furthermore, when the rubber composition forming the inner rubber layer does not contain the (D) component, as in Comparative Example 3, the heat resistance is insufficient. Furthermore, when the rubber composition forming the inner rubber layer contains the (B) to (D) components but the total content (B + C) of the (B) and (C) components is high, as in Comparative Example 4, the adhesion is insufficient. Also, when the rubber composition forming the inner rubber layer contains the (B) to (D) components but the mass ratio (B / C) of the (B) component to the (C) component is small, as in Comparative Example 5, the adhesion is 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 Fabrication>> 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 brass-plated wire (0.4 mm in diameter) was spirally braided around the outer surface of the intermediate rubber layer to form a plated wire layer. This process was repeated to form the 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, polyamide canvas was spirally wrapped 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 (Seat 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 Al 2 (OH) 13 CO 3 ・3.5H 2

[0100] 5 parts by mass of a hydroxybenzoate (DHT-4A, manufactured by Kyowa Chemical Industry Co., Ltd.), 1 part by mass of an antioxidant (Ozonone 3C, manufactured by Seiko Chemical Industry 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.) were blended and kneaded in a kneader to prepare a rubber composition.

[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 amount: 4 g / kg).

[0114] In the above example, a nylon mesh sheet is used as the organic fiber layer, but the present invention is not limited to this, and the type of organic fiber, the opening area (porosity), and other values ​​can be selected as appropriate. For example, the opening area (porosity) 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 referred to as "OP 2 / (OP + wire diameter) 2 " (OP = distance between threads).

[0115] Although the above examples show specific embodiments of the present invention, the examples are merely illustrative and should not be construed as limiting. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention.

[0116] The industrial hose of the present invention is useful as an industrial hose having 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.

[0117] 1: Inner rubber layer 2: Organic fiber layer 3: Intermediate rubber layer 4: Plated wire layer 5: Outer rubber layer

Claims

1. An industrial hose having a layered 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) A thiuram-based vulcanization accelerator. (D) N-phenyl-N-(trichloromethylthio)benzenesulfonamide.

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

3. The industrial hose according to claim 1 or 2, wherein component (A) is a rubber component containing acrylonitrile butadiene rubber and butadiene rubber.

4. The industrial hose according to any one of claims 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 claims 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 component (A).

6. An industrial hose according to any one of claims 1 to 5, wherein the content of component (D) is 0.3 to 1.0 part by mass per 100 parts by mass of component (A).

7. An industrial hose according to any one of claims 1 to 6, wherein the thickness of the inner rubber layer is 0.6 to 4.0 mm, and the thickness of the intermediate rubber layer is 0.1 to 1.0 mm.

8. An industrial hose as set forth in any one of claims 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.

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