Industrial Hose

Abstract

To provide an industrial hose capable of indicating high inter-layer adhesiveness without impairing physical property of a rubber layer and further without using an adhesive between a wire reinforcing layer and the rubber layer of the hose.SOLUTION: The present invention relates to an industrial hose in which at least one of an inner surface rubber layer 1 and an outer surface rubber layer 3 contains following components (A) to (C) and which consists of a vulcanizate of a diene-based rubber composition in which a ratio of the component (B) is 5 to 30 mass% with respect to 100 mass% of the component (A). A wire reinforcing layer 2 consists of a copper containing wire. The component (A) is a diene-based rubber, the component (B) is calcium carbonate of which the specific surface area is 4.8 m2 / g or more and the component (C) is sulfur.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an industrial hose used for various high-pressure hoses equipped with a wire-reinforced layer, such as high-pressure hydraulic hoses for construction machinery and mining machinery, and engine oil hoses for automobiles. [Background technology]

[0002] BACKGROUND ART Industrial hoses such as high-pressure hydraulic hoses used in construction machinery, mining machinery, etc. are usually provided with a wire reinforcement layer so that they can withstand high internal pressure. The layer configuration of the high-pressure hydraulic hose may, for example, include a hose having a wire reinforcement layer between an inner rubber layer and an outer rubber layer, or a hose having a layer configuration in which intermediate rubber layers and wire reinforcement layers are alternately stacked between the inner and outer rubber layers, with the wire reinforcement layers embedded in the intermediate rubber layers.

[0003] The metal wires constituting the wire reinforcing layer are usually plated metal wires in order to improve rust resistance. Furthermore, to improve the durability of the hose, it is necessary to firmly bond the wire-reinforced layer, which is made by braiding the metal wires, to the rubber layer in contact with it. In other words, if the adhesion between the wire-reinforced layer and the rubber layer is poor, the wires will move or become loose, which will have a negative impact on durability.

[0004] As described above, adhesives are usually used to firmly bond the wire reinforcing layer and the rubber layer together, but this method has problems such as making the manufacturing process complicated.

[0005] To obtain adhesion (peel resistance) to the wire reinforcement layer without using an adhesive (adhesive-less), for example, one method is to make the wire reinforcement layer from copper-containing wire, such as brass (copper-zinc alloy) plated wire, and use a diene-based rubber composition as the rubber layer material. Sulfur, which is a vulcanizing agent in the rubber layer material, chemically bonds with copper ions (Cu) in the wire reinforcement layer, turning the rubber layer near the interface with the wire reinforcement layer into a copper sulfide-containing layer, thereby achieving adhesion between the wire reinforcement layer and the rubber layer. However, during the vulcanization reaction of the rubber layer, copper ions from the wire-reinforced layer diffuse throughout the rubber layer, reducing the copper ion concentration in the rubber layer near the interface with the wire-reinforced layer, resulting in the problem that sufficient adhesion (peel resistance) cannot be obtained.

[0006] Therefore, in order to obtain good interlayer adhesion, various methods have been investigated, such as adding phenolic resin or maleic anhydride modified polymer to the rubber layer material, adding inorganic water-retaining materials such as silica, or improving the vulcanization accelerator in the rubber layer material (see, for example, Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 58-72436 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-254876 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-152311 [Patent Document 4] International Publication No. 2014 / 175186 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the existing methods described in the above-mentioned patent documents have many problems, such as excessive increase in rubber hardness, which leads to a decrease in fatigue resistance, and an increase in tackiness, which adversely affects workability and product appearance. For this reason, it is desired to obtain the effect of improving the adhesion to the wire-reinforced layer without impairing the physical properties of the rubber layer by a method different from the existing methods.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an industrial hose that can exhibit high interlayer adhesion between the wire-reinforced layer and the rubber layer of the hose without impairing the physical properties of the rubber layer and without using any adhesive. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above-mentioned problems, and in the course of their research, they have reconsidered a method for improving adhesion between the wire-reinforced layer and the rubber layer by forming a copper sulfide-containing layer in the rubber layer near the interface with the wire-reinforced layer, as described above. As mentioned above, this method had the problem that copper ions (Cu) from the wire-reinforced layer diffuse throughout the rubber layer during the vulcanization reaction of the rubber layer, reducing the copper ion concentration in the rubber layer near the interface with the wire-reinforced layer.As a result, it was not possible to form a copper sulfide-containing layer that exhibited sufficient adhesiveness. Therefore, the inventors investigated ways to increase the adhesion between the wire-reinforced layer and the rubber layer by using an additive in the rubber layer material to prevent copper ions from diffusing throughout the rubber layer and to keep the copper ions within the rubber layer near the wire-reinforced layer. To realize this, the inventors conducted various experiments and unexpectedly found that the rubber layer material had a BET specific surface area of ​​4.8 m 2 It was discovered that when a specific amount of calcium carbonate of 4.8m / g or more was added, the above phenomenon actually occurred, and a copper sulfide-containing layer exhibiting high adhesiveness was formed.2 The inventors have found that the desired objective can be achieved by adding a specific amount of calcium carbonate of 0.1g or more to the rubber layer without impairing the physical properties of the rubber layer and by exhibiting high interlayer adhesion with the wire-reinforced layer without using an adhesive.

[0011] That is, the gist of the present invention is the following [1] to [7]. [1] An industrial hose having a layer structure in which a wire-reinforced layer is laminated on at least one of the inner and outer peripheral surfaces of a tubular rubber layer, the wire reinforcement layer is made of copper-containing wire, The industrial hose, wherein the rubber layer comprises a vulcanizate of a diene-based rubber composition containing the following (A) to (C), and the ratio of (B) is 5 to 30 parts by mass per 100 parts by mass of (A): (A) Diene rubber. (B) BET specific surface area is 4.8m 2 / g or more of calcium carbonate. (C) Sulfur. [2] The industrial hose according to [1], wherein the diene rubber (A) is a diene rubber containing acrylonitrile butadiene rubber as a main component. [3] The calcium carbonate (B) has a BET specific surface area of ​​5.5 m 2 The industrial hose according to [1] or [2], wherein the calcium carbonate is 0.1g or more. [4] The industrial hose according to any one of [1] to [3], wherein the wire reinforcing layer is made of a wire plated with a copper-zinc alloy. [5] The industrial hose according to any one of [1] to [4], wherein the rubber layer is made of a vulcanizate of a diene rubber composition further containing the following (D): (D) (D) Silica. [6] The industrial hose according to any one of [1] to [5], wherein the sulfur (C) is sulfur containing insoluble sulfur. [7] The industrial hose according to any one of [1] to [6], wherein the wire-reinforced layer is laminated on at least the outer peripheral surface of the rubber layer. [Effects of the Invention]

[0012] The industrial hose of the present invention exhibits high interlayer adhesion between its wire-reinforced layer and rubber layer without impairing the physical properties of the rubber layer and without using any adhesive. Furthermore, the diffusion of copper ions from the wire-reinforced layer to the entire rubber layer is suppressed, thereby preventing deterioration of the rubber layer (copper damage). [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing an example of an industrial hose of the present invention. [Figure 2] FIG. 1 is an explanatory diagram showing a peel test in evaluating the adhesion between rubber and plated wire. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, an embodiment of the present invention will be described in detail, but the present invention is not limited to this embodiment. In the present invention, when the expression "X to Y" (X and Y are any numbers) is used, unless otherwise specified, it means "X or more and Y or less," and also includes the meaning of "preferably larger than X" or "preferably smaller than Y." Furthermore, when it is expressed as "X or more" (X is any number) or "Y or less" (Y is any number), it also includes the intention that "it is preferably greater than X" or "it is preferably less than Y."

[0015] As described above, an industrial hose (hereinafter referred to as "this industrial hose") that is one embodiment of the present invention has a layer structure in which a wire-reinforced layer is laminated on at least one of the inner and outer peripheral surfaces of a tubular rubber layer, the wire-reinforced layer being made of copper-containing wire, and the rubber layer containing the following (A) to (C), with the ratio of (B) being 5 to 30 parts by mass per 100 parts by mass of (A) being made of a vulcanizate of a diene-based rubber composition: (A) Diene rubber. (B) BET specific surface area is 4.8m 2 / g or more of calcium carbonate. (C) Sulfur.

[0016] 1 has a wire reinforcement layer 2 formed on the outer peripheral surface of an inner rubber layer 1, and an outer rubber layer 3 formed on the outer peripheral surface of the wire reinforcement layer 2. Therefore, it can be said that the hose has a layer structure in which the wire reinforcement layer 2 is laminated on the outer peripheral surface of the inner rubber layer 1, and also has a layer structure in which the wire reinforcement layer 2 is laminated on the inner peripheral surface of the outer rubber layer 3. 1 to be used as the present industrial hose, the wire-reinforced layer 2 must contain copper. Also, to use the hose shown in Fig. 1 as the present industrial hose, at least one of the inner rubber layer 1 and the outer rubber layer 3 must be a layer made of a vulcanizate of the specific diene rubber composition. Furthermore, by making at least the inner rubber layer 1 a layer made of a vulcanizate of the specific diene rubber composition (i.e., by forming a layer structure in which the wire-reinforced layer 2 is laminated on the outer peripheral surface of at least a rubber layer made of a vulcanizate of the specific diene rubber composition), problems such as the inner rubber layer 1 dropping off due to interlayer delamination and narrowing the flow path in the hose are eliminated, which is preferable. Note that it is more preferable that the outer rubber layer 3 is also a layer made of a vulcanizate of the specific diene rubber composition from the viewpoint of interlayer adhesion, etc.

[0017] Next, each component of the specific diene rubber composition will be described in detail below.

[0018] Diene rubber (A) Examples of the diene rubber (A) include natural rubber (NR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), isoprene rubber (IR), and butadiene rubber (BR). These may be used alone or in combination of two or more. Among these, when oil resistance is required, diene rubbers containing NBR as the main component (diene rubbers containing 50% by mass or more of NBR) are preferably used, and more preferably, only NBR is used. Note that when abrasion resistance is required, SBR and NR are preferably used. From the viewpoint of adhesion to the wire-reinforced layer 2, the NBR preferably has an acrylonitrile content (AN content) of 10 to 33 mass %, more preferably an AN content of 10 to 28 mass %. That is, if the AN content is too high, the vulcanization rate increases and furthermore, the bonds between polymers become stronger, making it difficult for sulfur to elute to the surface, which may result in a decrease in adhesion, whereas if the AN content is too low, the initial physical properties may be poor. Furthermore, the SBR preferably has a styrene content of 10 to 25% by mass, more preferably 15 to 25% by mass, from the viewpoint of adhesion to the wire-reinforced layer 2. That is, if the styrene content is too high, the vulcanization rate increases and furthermore, the bonds between polymers become stronger, making it difficult for sulfur to elute to the surface, which may result in a decrease in adhesion, whereas if the styrene content is too low, the initial physical properties may be poor.

[0019] Calcium carbonate (B) As for the calcium carbonate (B), from the viewpoint of the effect of the present invention (the effect of suppressing the diffusion of copper ions throughout the rubber layer and retaining the copper ions in the rubber layer near the wire-reinforced layer 2, thereby enhancing the adhesion between the wire-reinforced layer 2 and the rubber layer due to copper sulfide), as described above, calcium carbonate (B) having a BET specific surface area of ​​4.8 m 2 From the same viewpoint, the BET specific surface area of ​​the calcium carbonate (B) is 5.5 m / g or more. 2 / g or more, and 2The upper limit of the BET specific surface area of ​​the calcium carbonate (B) is usually 55 m 2 / g or less, preferably 40m 2 / g or less, more preferably 30m 2 / g or less. Examples of such calcium carbonate (B) commercially available include Hakuenka CC, Silver W, and Hakuenka O (all manufactured by Shiraishi Calcium Co., Ltd.). The BET specific surface area of ​​the calcium carbonate (B) 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 an adsorption gas with a BET specific surface area measuring device (Microdata Corporation, 4232-II).

[0020] The content of the calcium carbonate (B) relative to 100 parts by mass of the diene rubber (A) is, as described above, in the range of 5 to 30 parts by mass, preferably in the range of 5 to 20 parts by mass, and more preferably in the range of 10 to 20 parts by mass. That is, if the content of the calcium carbonate (B) is too small, the above-described effects of the present invention cannot be advantageously obtained, whereas if the content of the calcium carbonate (B) is too large, the effects of the present invention are inhibited, and deterioration in initial physical properties, heat resistance, and processability are observed.

[0021] 《Sulfur (C)》 As the sulfur (C), sulfur containing insoluble sulfur is preferred from the viewpoint of advantageously obtaining the adhesive effect with the wire-reinforcing layer 2 due to the above-mentioned action and effect of the present invention. Here, examples of insoluble sulfur include polymeric sulfur such as μ sulfur, π sulfur, and ω sulfur. These may be used alone or in combination of two or more. Specific examples of the insoluble sulfur include Sanfel (manufactured by Sanshin Chemical Co., Ltd.) and Sanfel EX (manufactured by Sanshin Chemical Co., Ltd.). The content of the insoluble sulfur relative to 100 parts by mass of the diene rubber (A) is preferably in the range of 0.2 to 4.8 parts by mass, and more preferably in the range of 0.5 to 4.5 parts by mass.

[0022] In addition to the insoluble sulfur described above, soluble sulfur can also be used as needed. By using insoluble sulfur and soluble sulfur in combination in this way, the sulfur (insoluble sulfur) that mainly contributes to adhesion to the wire-reinforced layer 2 and the sulfur (soluble sulfur) that mainly contributes to vulcanization of the rubber can each fully exhibit their respective functions. Here, examples of the soluble sulfur include sulfur having a cyclic structure, such as α sulfur, β sulfur, γ sulfur, and λ sulfur. These may be used alone or in combination of two or more. Specific examples of the soluble sulfur include Sulfax T-10 (manufactured by Tsurumi Chemical Industry Co., Ltd.), Kinkajirushi Fine Sulfur (manufactured by Tsurumi Chemical Industry Co., Ltd.), and Powdered Sulfur S (manufactured by Hosoi Chemical Industry Co., Ltd.). The content of the soluble sulfur relative to 100 parts by mass of the diene rubber (A) is preferably in the range of 0.2 to 4.8 parts by mass, more preferably in the range of 0.5 to 4.5 parts by mass.

[0023] In the present invention, insoluble sulfur refers to sulfur that is 90% by mass or more insoluble in carbon disulfide, preferably 95% by mass or more insoluble, more preferably 98% by mass or more insoluble, while soluble sulfur refers to sulfur that is 99.5% by mass or more soluble in carbon disulfide, preferably 99.9% by mass or more insoluble, more preferably 100% by mass.

[0024] The total amount of sulfur (C) is preferably in the range of 1.0 to 6.0 parts by mass, more preferably 1.0 to 5.0 parts by mass, relative to 100 parts by mass of the diene rubber (A). That is, within such a range, the above-mentioned effects of the present invention are advantageously obtained, high interlayer adhesion is exhibited, and the vulcanization of the rubber layer is favorably performed.

[0025] In addition to the components (A) to (C), the specific diene rubber composition may contain optional materials such as silica (D), carbon black, zinc oxide, stearic acid, processing aids, vulcanization accelerators, plasticizers, tackifiers, antioxidants, flame retardants, and scorch inhibitors, as needed.

[0026] It is preferable that the specific diene rubber composition contains silica (D) because the affinity with the wire is improved. From the viewpoint of further improving affinity with the wire, the content of the silica (D) is preferably in the range of 5 to 15 parts by mass, more preferably in the range of 5 to 10 parts by mass, per 100 parts by mass of the diene rubber (A).

[0027] From the viewpoint of reinforcement, the content of the carbon black is preferably in the range of 40 to 150 parts by mass, more preferably in the range of 60 to 130 parts by mass, per 100 parts by mass of the diene rubber (A).

[0028] The specific diene rubber composition can be prepared, for example, by appropriately blending the components (A) to (C) and, if necessary, the various optional materials as described above, and kneading them using a kneader, roll, Banbury mixer, or other kneading machine.

[0029] The present industrial hose shown in FIG. 1 can be produced, for example, as follows, by using the specific diene rubber composition for at least one of the rubber composition for forming the inner rubber layer 1 and the rubber composition for forming the outer rubber layer 3. That is, first, a rubber composition for forming the inner rubber layer 1 is extruded onto a mandrel using an extruder. Next, copper-containing wires are braided in a braid or spiral shape on the outer peripheral surface of this inner rubber layer 1 to form the wire-reinforced layer 2. Thereafter, a rubber composition for forming the outer rubber layer 3 is extruded onto the outer peripheral surface of the wire-reinforced layer 2. Finally, the laminate thus obtained is vulcanized (steam vulcanization, etc.) under predetermined conditions (for example, 140 to 170°C x 10 to 60 minutes), thereby producing an industrial hose having a layered structure as shown in FIG. 1.

[0030] The copper-containing wire used in the wire reinforcement layer 2 may be a copper wire, or a copper-plated or brass (copper-zinc alloy) plated wire made of iron or steel. Of these, a brass-plated wire is preferred from the viewpoints of flexibility, strength, etc. The diameter of the wire is usually in the range of 0.15 to 1.00 mm, preferably in the range of 0.20 to 0.80 mm.

[0031] The industrial hose is not limited to the layer structure shown in FIG. 1, but may have, for example, a structure in which multiple rubber layers made of the specific diene rubber composition and wire-reinforced layers 2 are alternately laminated, or may have a structure in which, in addition to these layer structures, an innermost layer and an outermost layer made of a material different from the specific diene rubber composition are laminated.

[0032] When an innermost layer made of a material other than the specific diene rubber composition is provided as described above, the material is preferably a rubber having excellent oil resistance, such as acrylonitrile butadiene rubber (NBR), hydrogenated acrylonitrile butadiene rubber (HNBR), acrylic rubber (ACM), ethylene acrylate rubber (AEM), chlorinated polyethylene (CM), chlorosulfonated polyethylene (CSM), and fluororubber (FKM). These may be used alone or in combination of two or more. Among these, NBR is preferred from the viewpoints of oil resistance, strength, and cost. Furthermore, in addition to rubber such as NBR, the rubber composition for forming the innermost layer may contain, as needed, a reinforcing material (such as carbon black), a white filler, a plasticizer, stearic acid, zinc oxide, a vulcanizing agent, a vulcanization accelerator, a processing aid, and the like.

[0033] Furthermore, when an outermost layer made of a material other than the specific diene rubber composition is provided as described above, the material is preferably a rubber with excellent weather resistance, such as 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), chlorosulfonated polyethylene (CSM), etc. 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. Furthermore, in addition to rubber such as CR, the rubber composition for forming the outermost layer may contain, as needed, a reinforcing material (carbon black, etc.), a white filler, a plasticizer, stearic acid, zinc oxide, an acid acceptor (highly activated magnesium, hydrotalcite, etc.), an antioxidant, a vulcanizing agent, a vulcanization accelerator, a processing aid, and the like.

[0034] In the present industrial hose, the hose inner diameter is usually in the range of 5 to 85 mm, and preferably in the range of 6 to 80 mm.

[0035] The thickness of the inner rubber layer 1 is usually in the range of 0.7 to 4.0 mm, and preferably in the range of 1.0 to 3.0 mm. The thickness of the outer rubber layer 3 is usually in the range of 0.5 to 2.5 mm, and preferably in the range of 0.8 to 2.0 mm.

[0036] This industrial hose can be used as a high-pressure hydraulic hose for construction machinery, mining machinery, and industrial vehicles (forklifts, automated guided vehicles, etc.), as well as various oil transport hoses with a wire reinforcement layer, such as engine oil hoses for automobiles. [Example]

[0037] Next, examples will be described together with comparative examples, but the present invention is not limited to these examples.

[0038] Prior to the Examples and Comparative Examples, the following materials were prepared. The BET specific surface areas of the calcium carbonates described below were measured by the method described above.

[0039] [NBR] Nipol DN302 (AN content: 27.5% by mass), manufactured by Zeon Corporation

[0040] [SBR] #1500 (styrene content: 23.5% by mass), manufactured by Sumitomo Chemical Co., Ltd.

[0041] [NR] RSS#3

[0042] [Calcium carbonate (i)] Hakuenka CC, manufactured by Shiraishi Calcium Co., Ltd., BET specific surface area: 26.0 m 2 / g

[0043] [Calcium carbonate(II)] Silver W, manufactured by Shiraishi Calcium Co., Ltd., BET specific surface area: 5.5m 2 / g

[0044] [Calcium carbonate (iii)] Shirai Enka O, manufactured by Shiraishi Calcium Co., Ltd., BET specific surface area: 55m 2 / g

[0045] [Calcium carbonate(iv)] Whiten P-30, manufactured by Shiraishi Calcium Co., Ltd., BET specific surface area: 3.4 m 2 / g

[0046] [Insoluble sulfur] Sanfer, manufactured by Sanshin Chemical Co., Ltd.

[0047] [Soluble sulfur] Sulfax T-10, manufactured by Tsurumi Chemical Industry Co., Ltd.

[0048] [silica] Nipsil VN-3, manufactured by Tosoh Silica Corporation

[0049] [Examples 1 to 10, Comparative Examples 1 to 5] The components shown in Tables 1 and 2 below were blended in the proportions shown in the tables. Five parts by mass of zinc oxide (Zinc Oxide Type 2, manufactured by Sakai Chemical Industry Co., Ltd.), one part by mass of stearic acid (Lunac S-70V, manufactured by Kao Corporation), two parts by mass of an antioxidant (2,2,4-trimethyl-1,2-dihydroquinoline polymer), 80 parts by mass of carbon black (Seast SO, manufactured by Tokai Carbon Co., Ltd.), 10 parts by mass of a plasticizer, and two parts by mass of a sulfenamide accelerator (Suncerer CZ, manufactured by Sanshin Chemical Industry Co., Ltd.) were then blended, and the mixture was kneaded using a 3-liter kneader to prepare a rubber composition. For the rubber composition containing NBR as the polymer, an ether ester-based plasticizer (Adeka Cizer RS-107, manufactured by ADEKA Corporation) was used as the plasticizer. For the rubber composition containing SBR as the polymer, an aromatic oil (Diana Process AC-12, manufactured by Idemitsu Showa Shell Co., Ltd.) was used as the plasticizer. For the rubber composition containing NR as the polymer, paraffin oil (Diana Process NM-280, manufactured by Idemitsu Kosan Co., Ltd.) was used as the plasticizer. Next, to evaluate the adhesion between the rubber layer and the wire-reinforced layer in the industrial hose, vulcanized bond samples with wires were prepared using the rubber composition and evaluated for adhesion according to the following criteria. The results are shown in Tables 1 and 2 below.

[0050] ≪Adhesiveness≫ An unvulcanized rubber sheet (100 mm × 100 mm, 2 mm thick) was prepared using the rubber composition, and a plated wire (0.4 mm diameter, 300 mm length) was placed on the rubber sheet. This was press-vulcanized at 150°C for 60 minutes under a surface pressure of 2 MPa to prepare a vulcanized adhesive sample (see Figure 2). Then, in the vulcanized bonded sample shown in Figure 2, the rubber 11 and the plated wire 12 were chucked, and the plated wire 12 was peeled off in the direction of the arrow X in accordance with the T-peel test of JIS K 6256, and the adhesion rate of the rubber 11 on the surface of the plated wire 12 was measured visually. The plated wire 12 used was a wire plated with the plating shown in the "Wire Plating Type" in Tables 1 and 2 below, i.e., a steel wire plated with either Cu / Zn (brass plating of Cu / Zn = 65% by mass / 35% by mass), Cu (copper plating), or Ni (nickel plating). The adhesion rate of the rubber 11 on the surface of the plated wire 12 was evaluated according to the following criteria to evaluate the adhesiveness. ○: Adhesion rate is 80% or more △: Adhesion rate is 50% or more but less than 80% ×: adhesion rate is less than 50%

[0051] [Table 1]

[0052] [Table 2]

[0053] From the results in Tables 1 and 2, it was found that the vulcanization bonded samples of the Examples had a high adhesion rate of rubber on the surface of the plated wire, and therefore had excellent adhesion between the rubber and the plated wire. Furthermore, in an industrial hose having the layer configuration shown in FIG. 1, when the rubber composition used in the Examples was used as the material for forming at least one of the inner rubber layer 1 and the outer rubber layer 3, and the plated wire used in the Examples was used as the wire for the wire reinforcement layer 2, strong adhesion was achieved between the rubber layer made of the rubber composition used in the Examples and the wire reinforcement layer, even without adhesive, and the industrial hose exhibited excellent performance.

[0054] In contrast, Comparative Example 1 was conducted under the same conditions as Example 2 except that the BET specific surface area of ​​the calcium carbonate in the rubber did not satisfy the requirements of the present invention, but the desired adhesiveness was not obtained. Comparative Examples 2 to 4 were conducted under the same conditions as Example 2 except that the content of calcium carbonate in the rubber did not satisfy the requirements of the present invention, but the desired adhesiveness was not obtained. Comparative Example 5 was conducted under the same conditions as Examples 1 and 2 except that a nickel-plated wire was used as the plated wire (i.e., no copper-containing wire was used), but the desired adhesiveness was not obtained. This clearly shows that calcium carbonate in the rubber itself does not function as a factor imparting adhesiveness. Furthermore, it was found that unless the combination of the rubber layer material and the wire-reinforced layer material specified in the present invention is satisfied, a layer exhibiting strong adhesiveness (copper sulfide-containing layer) is not formed at the interface between the two layers, and the desired adhesiveness cannot be obtained. [Industrial Applicability]

[0055] The industrial hose of the present invention can be used as a high-pressure hydraulic hose for construction machinery, mining machinery, and industrial vehicles (forklifts, automated guided vehicles, etc.), as well as various oil transport hoses equipped with a wire-reinforced layer, such as engine oil hoses for automobiles.

Claims

1. An industrial hose having a layer structure in which a wire-reinforced layer is laminated on at least one of an inner circumferential surface and an outer circumferential surface of a tubular rubber layer, the wire reinforcement layer is made of copper-containing wire, The rubber layer comprises a vulcanizate of a diene-based rubber composition containing the following components (A) to (C), and the ratio of (B) is 5 to 30 parts by mass per 100 parts by mass of (A): (A) Diene rubber. (B) BET specific surface area is 4.8 m 2 / g or more of calcium carbonate. (C) Sulfur.

2. 2. The industrial hose according to claim 1, wherein the diene rubber (A) is a diene rubber containing acrylonitrile butadiene rubber as a main component.

3. The calcium carbonate (B) has a BET specific surface area of ​​5.5 m 2 3. The industrial hose according to claim 1, wherein the calcium carbonate has a molecular weight of 1 / g or more.

4. 4. The industrial hose according to claim 1, wherein the wire reinforcing layer is made of copper-zinc alloy-plated wire.

5. The industrial hose according to any one of claims 1 to 4, wherein the rubber layer comprises a vulcanizate of a diene-based rubber composition further containing the following (D): (D) Silica.

6. The industrial hose according to any one of claims 1 to 5, wherein the sulfur (C) is sulfur containing insoluble sulfur.

7. The industrial hose according to any one of claims 1 to 6, wherein the wire reinforcement layer is laminated on at least an outer peripheral surface of the rubber layer.

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