Rubber composition for coating a plated wire reinforcement layer and high-pressure hose using the same

Abstract

A rubber composition for coating a reinforcing layer of a plated wire, which is composed of a diene rubber composition, wherein the diene rubber composition contains the following components (A) to (E), and the content ratio is 5 to 20 parts by weight of component (B), 0.2 to 4.8 parts by weight of component (C), 0.2 to 4.8 parts by weight of component (D), 40 to 100 parts by weight of component (E), and the total amount of components (C) and (D) is 1.0 to 6.0 parts by weight. As a result, the physical properties of the rubber are not impaired, and further, even without using an adhesive, the adhesion to the reinforcing layer composed of the plated wire is excellent. (A) Diene rubber, (B) Plasticizer, (C) Insoluble sulfur, (D) Soluble sulfur, (E) Nitrogen adsorption specific surface area of ​​56m 2 / g or less carbon black.

Description

Technical Field

[0001] The present invention relates to a rubber composition for coating a plated wire reinforcement layer used in various oil transport hoses having a plated wire reinforcement layer, such as high-pressure hydraulic hoses for construction machinery and mining machinery, and engine oil hoses for automobiles, and a high-pressure hose using the rubber composition. Background Art

[0002] High-pressure hydraulic hoses used in construction machinery, mining machinery, etc. are usually provided with a wire reinforcement layer so as to be able to withstand higher internal pressures.

[0003] As a layer structure of the high-pressure hydraulic hose, for example, a plurality of intermediate rubber layers and wire reinforcement layers are alternately stacked between an inner surface rubber layer and an outer surface rubber layer, and the wire reinforcement layer is embedded in the intermediate rubber layer.

[0004] The metal wire constituting the wire reinforcing layer is generally a plated metal wire (plated wire) in order to improve rust resistance.

[0005] Furthermore, in order to improve the durability of the high-pressure hydraulic hose, the plated wire reinforcement layer formed by braiding the plated wires and the rubber layer (especially the intermediate rubber layer) in contact with the plated wire reinforcement layer need to be firmly bonded. That is, if the adhesion between the plated wire reinforcement layer and the rubber layer is poor, the wires will move or loosen, which will adversely affect the durability.

[0006] As described above, an adhesive is generally used to firmly bond the plated wire reinforcement layer and the rubber layer. However, this method has a problem that the production process becomes complicated.

[0007] In order to improve the adhesion with the plated wire reinforcement layer without using an adhesive (adhesive-free), for example, using a diene rubber composition as the rubber layer material and increasing the amount of sulfur in the diene rubber composition have been studied. However, if the amount of sulfur is large, more crosslinking points are formed in the rubber, which reduces the heat resistance, so this method is not realistic.

[0008] Therefore, in order to obtain good adhesion with a sulfur blending amount capable of maintaining heat resistance, various studies have been conducted on methods such as adding phenolic resins, maleic anhydride-modified polymers, etc. to the above-mentioned rubber layer materials, or improving the vulcanization accelerators in the above-mentioned rubber layer materials (for example, refer to Patent Documents 1 to 3).

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 58-72436

[0012] Patent Document 2: Japanese Patent Application Publication No. 2010-254876

[0013] Patent Document 3: Japanese Patent Application Publication No. 2014-152311 Summary of the invention

[0014] Problems to be solved by the invention

[0015] However, the conventional methods as described above have many problems, such as excessive increase in rubber hardness leading to a decrease in fatigue resistance, and increase in viscosity causing adverse effects on workability and product appearance. Therefore, it is desired to obtain an effect of improving the adhesion to the plated wire reinforcement layer without impairing the physical properties of the rubber by a method different from the conventional methods.

[0016] The present invention has been made in view of the above circumstances and provides a rubber composition for covering a plated wire reinforcement layer which does not impair the rubber properties and has excellent adhesion to a reinforcement layer composed of a plated wire even without using an adhesive, and a high-pressure hose using the rubber composition.

[0017] Means used to solve problems

[0018] The inventors of the present invention have repeatedly conducted in-depth studies to solve the above-mentioned problems. In the course of the studies, the inventors of the present invention used a diene rubber composition as the intermediate rubber layer material of the high-pressure hose, and further conducted various studies focusing on the type and amount of sulfur in the above-mentioned rubber layer material. As described above, if the amount of sulfur in the rubber layer material is simply increased, although the adhesion to the plated wire reinforcement layer is improved, the problem of reduced rubber properties occurs. Therefore, the inventors of the present invention have studied the use of sulfur that mainly contributes to the adhesion to the plated wire reinforcement layer and sulfur that mainly contributes to the vulcanization of the rubber, so as to fully exert the functions of each sulfur and suppress the overall amount of sulfur, thereby achieving the desired purpose.

[0019] Furthermore, various experiments were conducted and it was found that a plasticizer (B), insoluble sulfur (C), soluble sulfur (D) and a nitrogen adsorption specific surface area of ​​56 m2 were mixed in a specific ratio with respect to a diene rubber (A). 2 / g or less carbon black (E), the above-mentioned soluble sulfur (D) with a ring structure and early activation is subjected to a small specific surface area (nitrogen adsorption specific surface area of ​​56m 2 / g or less) carbon black (E) contributes to vulcanization, while on the other hand, the polymeric insoluble sulfur (C) that is not easily affected by the above-mentioned specific carbon black (E) is squeezed out from the rubber composition to be vulcanized due to the action of the plasticizer (B), and becomes easy to gather near the surface of the plated wire. At the same time, it was found that the above-mentioned insoluble sulfur (C) is activated later than the soluble sulfur (D), and reacts with the plating component (such as copper) on the surface of the above-mentioned plated wire to form an adhesive layer of the above-mentioned plating component and sulfur, thereby showing adhesion. It was found that while suppressing the overall sulfur amount, the adhesion with the plated wire becomes strong, and the vulcanization of the rubber is sufficient, and the rubber physical properties are also good, so that the desired purpose can be achieved.

[0020] That is, in order to achieve the above-mentioned object, the gist of the present invention lies in the following [1] to [9].

[0021] [1] A rubber composition for covering a plated wire reinforcement layer, the rubber composition being used for covering the periphery of a reinforcement layer in a high-pressure hose having a reinforcement layer composed of plated wires, characterized in that the rubber composition for covering the plated wire reinforcement layer is composed of a diene rubber composition, the diene rubber composition containing the following components (A) to (E), wherein the content ratio is 5 to 20 parts by weight of the component (B), 0.2 to 4.8 parts by weight of the component (C), 0.2 to 4.8 parts by weight of the component (D), and 40 to 100 parts by weight of the component (E), and the total amount of the components (C) and (D) is 1.0 to 6.0 parts by weight.

[0022] (A) diene rubber,

[0023] (B) plasticizers,

[0024] (C) insoluble sulfur,

[0025] (D) Soluble sulfur,

[0026] (E) Nitrogen adsorption specific surface area is 56m 2 / g or less carbon black.

[0027] [2] The rubber composition for coating a plated wire reinforcement layer according to [1], wherein the plasticizer (B) is at least one selected from the group consisting of aromatic oils, ether-ester plasticizers, and process oils.

[0028] [3] The rubber composition for coating a plated wire reinforcement layer according to [1], wherein the diene rubber (A) is styrene butadiene rubber, and the plasticizer (B) is an aromatic oil.

[0029] [4] The rubber composition for coating a plated wire reinforcement layer according to [1], wherein the diene rubber (A) is acrylonitrile butadiene rubber, and the plasticizer (B) is an ether ester plasticizer.

[0030] [5] The rubber composition for coating a plated wire reinforcement layer according to [1] or [2], wherein the diene rubber (A) is a styrene-butadiene rubber having a styrene content of 10 to 25% by weight.

[0031] [6] The rubber composition for coating a plated wire reinforcement layer according to [1] or [2], wherein the diene rubber (A) is an acrylonitrile-butadiene rubber having an acrylonitrile content of 10 to 33% by weight.

[0032] [7] A high-pressure hose, characterized in that it comprises: a rubber layer composed of the rubber composition for coating a plated wire reinforcement layer according to any one of [1] to [6]; and a plated wire reinforcement layer, wherein the plated wire reinforcement layer is embedded and installed in the rubber layer.

[0033] [8] A high-pressure hose, characterized in that it comprises: a rubber layer composed of the rubber composition for coating a plated wire reinforcement layer according to any one of [1] to [6]; and a plated wire reinforcement layer, the plated wire reinforcement layer being laminated on at least one of the inner peripheral surface and the outer peripheral surface of the rubber layer.

[0034] [9] The high-pressure hose according to [7] or [8], wherein the peak intensity of sulfur element measured by energy dispersive X-ray analysis (EDX) at a portion of the rubber layer within a range from a contact surface with the plated wire reinforcement layer to 50 μm is higher than the peak intensity of sulfur element measured at a portion of the rubber layer outside the range.

[0035] Effects of the Invention

[0036] From the above, it can be seen that the rubber composition for coating the plated wire reinforcement layer of the present invention will not damage the rubber properties, and the adhesion with the reinforcement layer composed of the plated wire can be improved even without using an adhesive. As a result, the rubber layer material (especially the intermediate layer material) of the high-pressure hose can exhibit excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram showing an example of the high-pressure hose of the present invention.

[0038] Figure 2 It is a schematic diagram showing another example of the high-pressure hose of the present invention.

[0039] Figure 3This is an explanatory diagram showing a peel test in evaluating the adhesion between rubber and a brass plated wire. DETAILED DESCRIPTION

[0040] Next, an embodiment of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

[0041] As described above, the rubber composition for covering a plated wire reinforcement layer of the present invention is a rubber composition for covering the periphery of the reinforcement layer in a high-pressure hose having a reinforcement layer composed of a plated wire. The rubber composition for covering a plated wire reinforcement layer of the present invention is composed of a diene rubber composition, wherein the diene rubber composition contains the following components (A) to (E), and the content ratio is 5 to 20 parts by weight of the component (B), 0.2 to 4.8 parts by weight of the component (C), 0.2 to 4.8 parts by weight of the component (D), and 40 to 100 parts by weight of the component (E), and the total amount of the components (C) and (D) is 1.0 to 6.0 parts by weight.

[0042] (A) diene rubber,

[0043] (B) plasticizers,

[0044] (C) insoluble sulfur,

[0045] (D) Soluble sulfur,

[0046] (E) Nitrogen adsorption specific surface area is 56m 2 / g or less carbon black.

[0047] In the present invention, the insoluble sulfur (C) refers to sulfur that is 90% by weight or more insoluble in carbon disulfide, and the insoluble sulfur (C) is preferably 95% by weight or more insoluble in carbon disulfide, and more preferably 98% by weight or more insoluble in carbon disulfide. In addition, the soluble sulfur (D) refers to sulfur that is 99.5% by weight or more soluble in carbon disulfide, and the soluble sulfur (D) is preferably 99.9% by weight or more soluble in carbon disulfide, and more preferably 100% by weight soluble in carbon disulfide.

[0048] Hereinafter, the details of each component in the rubber composition for coating a plated wire reinforcement layer of the present invention will be described.

[0049] 《Diene rubber (A)》

[0050] As the above-mentioned diene rubber (A), for example, natural rubber (NR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), isoprene rubber (IR), butadiene rubber (BR), etc. can be listed. These can be used alone or in combination of two or more. Among them, when oil resistance is required, NBR is preferred, and when wear resistance is required, SBR and NR are preferred.

[0051] Furthermore, from the viewpoint of adhesion to the reinforcing layer composed of the plated wire, the NBR is preferably an NBR having an acrylonitrile content (AN content) of 10 to 33% by weight, and more preferably an NBR having an AN content of 10 to 28% by weight. That is, if the AN content is too large, the vulcanization speed becomes faster, and further the bond between polymers becomes stronger, and sulfur is difficult to dissolve to the surface, so there is a risk of reduced adhesion, and if the AN content is too small, there is a risk of lowering the initial physical properties.

[0052] In addition, from the viewpoint of adhesion to the reinforcing layer composed of the plated wire, the SBR is preferably an SBR having a styrene content of 10 to 25% by weight, and more preferably an SBR having a styrene content of 15 to 25% by weight. That is, if the styrene content is too high, the vulcanization rate becomes faster, and further the bond between polymers becomes stronger, and sulfur is difficult to dissolve to the surface, so there is a risk of reduced adhesion, and if the styrene content is too low, there is a risk of lowering the initial physical properties.

[0053] 《Plasticizer (B)》

[0054] Examples of the plasticizer (B) include aromatic oils, ether-ester plasticizers, and process oils.

[0055] Here, examples of the aromatic oil include Diana process AC-12, Diana process AC-460, Diana process AH-16 (all manufactured by Idemitsu Showa Shell Co., Ltd.), JSO AROMA 790 (manufactured by Japan Sun Oil Company), Aromax 1, and Aromax 3 (all manufactured by Fuji Kosan Co., Ltd.).

[0056] Examples of the ether ester plasticizer include plasticizers having both an ether bond and an ester bond in one molecule, and specific examples include adipic acid ether ester plasticizers such as bis[2-(2-butoxyethoxy)ethyl]adipate.

[0057] Examples of the process oil include naphthenic oil and paraffinic oil.

[0058] Furthermore, these can be used alone or in combination of two or more.

[0059] Furthermore, when the diene rubber (A) is styrene-butadiene rubber and the plasticizer (B) is an aromatic oil, the compatibility between the diene rubber (A) and the plasticizer (B) is excellent, which is preferred.

[0060] In addition, when the diene rubber (A) is an acrylonitrile-butadiene rubber and the plasticizer (B) is an ether-ester plasticizer, the compatibility between the diene rubber (A) and the plasticizer (B) is also excellent, which is preferred.

[0061] As described above, the content of the plasticizer (B) is in the range of 5 to 20 parts by weight, preferably in the range of 5 to 18 parts by weight, and more preferably in the range of 8 to 15 parts by weight, relative to 100 parts by weight of the diene rubber (A). That is, if the content of the plasticizer (B) is too small, the oozing out of the insoluble sulfur (C) decreases, and accordingly, the adhesion effect with the plated wire cannot be fully obtained, and if the content of the plasticizer (B) is too large, there is a risk of causing a decrease in rubber properties and a decrease in adhesion due to the oozing out of the plasticizer (B).

[0062] 《Insoluble Sulfur (C)》

[0063] As the above-mentioned insoluble sulfur (C), for example, polymeric sulfur such as μ sulfur, π sulfur, and ω sulfur can be cited. These can be used alone or in combination of two or more. In addition, the above-mentioned insoluble sulfur can be specifically listed as sanfel (manufactured by Sanshin Chemical Co., Ltd.), sanfel EX (manufactured by Sanshin Chemical Co., Ltd.), etc.

[0064] Furthermore, the content of the insoluble sulfur (C) is in the range of 0.2 to 4.8 parts by weight, preferably in the range of 0.5 to 4.5 parts by weight, and more preferably in the range of 1.0 to 3.5 parts by weight, relative to 100 parts by weight of the diene rubber (A), as described above. That is, if the content of the insoluble sulfur (C) is too small, the bonding effect with the plated wire cannot be sufficiently obtained, and if the content of the insoluble sulfur (C) is too large, a large amount of insoluble sulfur that does not react with the plated wire is eluted on the surface, which may hinder the bonding effect with the plated wire.

[0065] 《Soluble Sulfur (D)》

[0066] As the above-mentioned soluble sulfur (D), for example, sulfur having a ring structure such as α sulfur, β sulfur, γ sulfur, and λ sulfur can be cited. These can be used alone or in combination of two or more. In addition, the above-mentioned soluble sulfur can be specifically listed as Kinkain powdered sulfur (manufactured by Tsurumi Chemical Industry Co., Ltd.), powdered sulfur S (manufactured by Hosoi Chemical Industry Co., Ltd.), etc.

[0067] Furthermore, the content of the soluble sulfur (D) is in the range of 0.2 to 4.8 parts by weight, preferably in the range of 0.5 to 4.5 parts by weight, and more preferably in the range of 1.0 to 3.5 parts by weight, relative to 100 parts by weight of the diene rubber (A), as described above. That is, if the content of the soluble sulfur (D) is too small, the vulcanization of the rubber cannot be fully performed, resulting in poor rubber properties, and if the content of the soluble sulfur (D) is too large, there is a risk that the soluble sulfur will bloom on the rubber surface before vulcanization and hinder the adhesion effect with the plated wire.

[0068] Furthermore, the total amount of the insoluble sulfur (C) and the soluble sulfur (D) is in the range of 1.0 to 6.0 parts by weight, preferably 1.0 to 5.0 parts by weight, and more preferably 1.5 to 4.0 parts by weight, relative to 100 parts by weight of the diene rubber (A), as described above. That is, if it is in such a range, the heat resistance and the like are not deteriorated, and the vulcanization and the like are improved.

[0069] Carbon Black (E)

[0070] As the carbon black, as described above, carbon black having a nitrogen adsorption specific surface area of ​​56 m 2 In addition, from the viewpoint of further improving the vulcanization effect of the rubber composition by the soluble sulfur (D), it is preferred to use a carbon black (E) having a nitrogen adsorption specific surface area of ​​20 to 50 m 2 / g of carbon black, preferably a carbon black having a nitrogen adsorption specific surface area of ​​25 to 45 m 2 / g of carbon black. The nitrogen adsorption specific surface area is defined in JIS K 6217 as the nitrogen adsorption specific surface area per unit weight (m 2 / g). Specific examples of the carbon black include SEAST SO and SEAST 116HM (both manufactured by Tokai Carbon Co., Ltd.). These may be used alone or in combination of two or more.

[0071] Furthermore, the content of the specific carbon black (E) is in the range of 40 to 100 parts by weight, preferably in the range of 50 to 90 parts by weight, and more preferably in the range of 60 to 90 parts by weight, relative to 100 parts by weight of the diene rubber (A), as described above. That is, if the content of the specific carbon black (E) is too small, the effect of improving the vulcanization of the rubber composition by the soluble sulfur (D) and the effect of improving the adhesion to the plated wire by the insoluble sulfur (C) cannot be fully obtained, and if the content of the specific carbon black (E) is too large, the vulcanization is activated, and the insoluble sulfur is also used for vulcanization, so there is a risk of hindering the adhesion effect to the plated wire.

[0072] Furthermore, in the rubber composition for coating the plated wire reinforcement layer of the present invention, in addition to the above components (A) to (E), optional materials such as zinc oxide, stearic acid, silica, processing aids, and vulcanization accelerators may be blended as necessary.

[0073] The rubber composition can be prepared, for example, by appropriately blending the components (A) to (E) and, if necessary, the above-mentioned various optional materials, and kneading them using a kneading machine such as a kneader, a roll, or a Banbury mixer.

[0074] As described above, the rubber composition for covering a plated wire reinforcement layer of the present invention is a rubber composition for covering the periphery of a reinforcement layer in a high-pressure hose including a reinforcement layer composed of plated wires.

[0075] Examples of the high-pressure hose include high-pressure hoses of the following aspects (1) and (2).

[0076] (1) A high-pressure hose comprising a rubber layer formed from the rubber composition for coating a plated wire reinforcement layer of the present invention and a plated wire reinforcement layer, wherein the plated wire reinforcement layer is embedded in the rubber layer.

[0077] (2) A high-pressure hose comprising a rubber layer formed from the rubber composition for coating a plated wire reinforcement layer of the present invention and a plated wire reinforcement layer, wherein the plated wire reinforcement layer is laminated on at least one of the inner peripheral surface and the outer peripheral surface of the rubber layer.

[0078] Here, Figure 1 The high-pressure hose shown has an intermediate rubber layer 2a formed on the outer peripheral surface of the inner surface rubber layer 1, a reinforcing layer 3 composed of a plated wire is formed on the outer peripheral surface of the intermediate rubber layer 2a, an intermediate rubber layer 2b is formed on the outer peripheral surface of the reinforcing layer 3, and an outer surface rubber layer 4 is formed on the outer peripheral surface of the intermediate rubber layer 2b. Furthermore, by making the intermediate rubber layers 2a and 2b the layers composed of the rubber composition for coating the plated wire reinforcing layer of the present invention, a high-pressure hose of the embodiment shown in (1) above can be obtained.

[0079] in addition, Figure 2 The high-pressure hose shown has an intermediate rubber layer 2 formed on the outer peripheral surface of a reinforcing layer 13a composed of a plated wire, and a reinforcing layer 13b composed of a plated wire is formed on the outer peripheral surface of the intermediate rubber layer 2. Furthermore, by making the intermediate rubber layer 2 a layer formed of the rubber composition for coating the plated wire reinforcing layer of the present invention, a high-pressure hose of the embodiment shown in (2) above can be obtained.

[0080] In addition, the high-pressure hose of the present invention is not limited to the following as long as it has a laminated structure in which the intermediate rubber layer and the reinforcing layer are alternately and repeatedly laminated. Figure 1as well as Figure 2 The layer structure shown may also be a hose having a laminated structure of two layers, intermediate rubber layer / reinforcement layer, four layers (intermediate rubber layer / reinforcement layer / intermediate rubber layer / reinforcement layer), six layers (intermediate rubber layer / reinforcement layer / intermediate rubber layer / reinforcement layer / intermediate rubber layer / reinforcement layer), or eight layers (intermediate rubber layer / reinforcement layer / intermediate rubber layer / reinforcement layer / intermediate rubber layer / reinforcement layer / intermediate rubber layer / reinforcement layer).

[0081] In addition, it is preferable that the peak intensity of sulfur element measured by energy dispersive X-ray analysis (EDX) in the intermediate rubber layer within a range of 50 μm from the contact surface with the reinforcing layer (plated wire reinforcing layer) is higher than the peak intensity of sulfur element measured in the intermediate rubber layer outside the above range. That is, as described above, the adhesive layer is well formed in the intermediate rubber layer by the contact reaction with the plating of the reinforcing layer, thereby exhibiting good adhesion.

[0082] The measurement conditions of the energy dispersive X-ray analysis (EDX) can be performed, for example, under the following conditions.

[0083] 《Energy dispersive X-ray analysis (EDX) measurement conditions》

[0084] Cross-section processing: ion milling

[0085] ·Analysis and measurement conditions

[0086] Device name: Scanning electron microscope S-4800 (manufactured by Hitachi High-Technologies Corporation)

[0087] Energy dispersive X-ray microanalyzer X-Max (manufactured by Horiba, Ltd.)

[0088] Image type: reflected electron image

[0089] Accelerating voltage: 15 kV

[0090] Conductive treatment: C evaporation

[0091] Magnification:×100k

[0092] Element type: Sulfur

[0093] In the present invention, from the viewpoint of durability and flexibility, the tensile stress (M 100 ) is preferably 3.0 MPa or more, more preferably 3.0 to 6.0 MPa, and further preferably 3.5 to 5.0 MPa.

[0094] In addition, the above tensile stress (M 100) can be measured, for example, in accordance with JIS K 6251.

[0095] The reinforcing layer is a layer formed by braiding the plated wires into a blade shape, a spiral shape, or the like in order to increase the strength of the entire hose.

[0096] Examples of the plating treatment in the plated wire include copper plating, zinc plating, brass plating (copper-zinc alloy), nickel plating, tin plating, and cobalt plating, and brass plating is preferred.

[0097] The plated wire generally has a diameter in the range of 0.15 to 1.00 mm, and preferably has a diameter in the range of 0.20 to 0.80 mm.

[0098] In addition, in Figure 1 In the case where the inner surface rubber layer 1 is formed like the high-pressure hose shown in FIG. 1 , as its material, it is preferably a rubber with excellent oil resistance, for example, acrylonitrile butadiene rubber (NBR), hydrogenated acrylonitrile butadiene rubber (HNBR), acrylic rubber (ACM), ethylene acrylate rubber (AEM), chlorinated polyethylene (CM), chlorosulfonated polyethylene (CSM), fluororubber (FKM) etc. These can be used alone or in combination of two or more. Among them, NBR is preferred from the viewpoint of oil resistance, strength and cost.

[0099] In addition, in the rubber composition used to form the above-mentioned inner surface rubber layer 1, in addition to rubber such as NBR, reinforcing materials (such as carbon black), white fillers, plasticizers, stearic acid, zinc white, vulcanizers, vulcanization accelerators, processing aids, etc. can also be appropriately formulated as needed.

[0100] Furthermore, in Figure 1 In the case where the outer surface rubber layer 4 is formed like the high-pressure hose shown in the figure, as its material, it is preferably a rubber with excellent weather resistance, for example, 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 vinyl chloride (PVC), acrylic rubber (ACM), ethylene acrylate rubber (AEM), chlorinated polyethylene (CM), chlorosulfonated polyethylene (CSM) etc. They can be used alone or in combination of two or more. Among them, from the viewpoint of weather resistance, cost, oil resistance, CR is preferred.

[0101] In addition, in the rubber composition used to form the above-mentioned outer surface rubber layer 4, in addition to rubber such as CR, reinforcing materials (carbon black, etc.), white fillers, plasticizers, stearic acid, zinc white, acid absorbers (highly active magnesium, hydrotalcite, etc.), antioxidants, vulcanizers, vulcanization accelerators, processing aids, etc. can also be appropriately formulated as needed.

[0102] Figure 1 The high-pressure hose of the present invention shown can be produced, for example, as follows. That is, first, using an extrusion molding machine, the rubber composition for forming the inner surface rubber layer is extruded onto a mandrel to form an inner surface rubber layer 1. Next, the rubber composition for forming the intermediate rubber layer is extruded on the outer peripheral surface of the inner surface rubber layer 1 to form an intermediate rubber layer 2a. Next, on the outer peripheral surface of the intermediate rubber layer 2a, a plated wire such as a brass plated wire is woven into a spiral shape to form a reinforcing layer 3. Thereafter, the rubber composition for forming the intermediate rubber layer is extruded on the outer peripheral surface of the reinforcing layer 3 to form an intermediate rubber layer 2b. Furthermore, the rubber composition for forming the outer surface rubber layer is extruded on the outer peripheral surface of the intermediate rubber layer 2b to form an outer surface rubber layer 4. Finally, by vulcanizing the laminate under predetermined conditions (for example, 140 to 170°C × 10 to 60 minutes) (steam vulcanization, etc.), the above-mentioned Figure 1 A high-pressure hose with a layer structure as shown.

[0103] The high pressure hose of the present invention is not limited to Figure 1 As described above, the layer structure shown in FIG. Figure 2 The layer structure shown is a structure in which a plurality of intermediate rubber layers and reinforcing layers are alternately stacked.

[0104] In the high-pressure hose of the present invention, the hose inner diameter is usually in the range of 5 to 85 mm, preferably in the range of 6 to 80 mm, and the hose outer diameter is usually in the range of 9 to 100 mm, preferably in the range of 10 to 85 mm.

[0105] In addition, the thickness of the inner surface rubber layer 1 is usually in the range of 0.7 to 4.0 mm, preferably in the range of 1.0 to 3.0 mm, the thickness of the entire intermediate rubber layer is preferably in the range of 0.1 to 0.5 mm, particularly preferably in the range of 0.2 to 0.4 mm, and the thickness of the outer surface rubber layer 4 is usually in the range of 0.5 to 2.5 mm, preferably in the range of 0.8 to 2.0 mm.

[0106] Example

[0107] Next, examples will be described together with comparative examples, but the present invention is not limited to these examples.

[0108] First, before preparing Examples and Comparative Examples, the following materials were prepared.

[0109] [SBR]

[0110] Tufdene 1000, manufactured by Asahi Kasei Corporation, styrene content: 18 wt%

[0111] [NBR]

[0112] Nipol DN302, manufactured by ZEON, Japan, AN content: 28 wt%

[0113] [NR]

[0114] RSS#3

[0115] [Plasticizer (i)]

[0116] Aromatic oil (Diana process AC-12, manufactured by Idemitsu Showa Shell Co., Ltd.)

[0117] [Plasticizer (ii)]

[0118] Ether ester oil (ADK CIZER RS-107, manufactured by ADEKA Corporation)

[0119] [Plasticizer (iii)]

[0120] Paraffin oil (Diana process NM-280, manufactured by Idemitsu Kosan Co., Ltd.)

[0121] [Carbon black (i)]

[0122] SEAST SO, manufactured by Tokai Carbon Co., Ltd., nitrogen adsorption specific surface area: 42m 2 / g

[0123] [Carbon black (ii)]

[0124] SEAST 116HM, manufactured by Donghai Carbon Co., Ltd., nitrogen adsorption specific surface area: 56m 2 / g

[0125] [Carbon black (iii)]

[0126] SEAST 300, manufactured by Donghai Carbon Co., Ltd., nitrogen adsorption specific surface area: 84m 2 / g

[0127] [Insoluble sulfur]

[0128] Sanfel, manufactured by Sanshin Chemical Co.

[0129] [Soluble sulfur]

[0130] Jinhua printed micro powder sulfur, manufactured by Tsurumi Chemical Industry Co., Ltd.

[0131] [Examples 1 to 16, Comparative Examples 1 to 13]

[0132] The components shown in Table 1 and Table 2 described later were blended in the ratios shown in the tables and kneaded using a 3 L kneader to prepare rubber compositions.

[0133] The rubber compositions of Examples and Comparative Examples obtained in this manner were used to evaluate the following properties. The results are shown together in Tables 1 and 2 described below.

[0134] Adhesion

[0135] The rubber composition was used to prepare an unvulcanized rubber sheet (100 mm × 100 mm, 2 mm thick), on which a brass plated wire (wire diameter 0.4 mm, length 300 mm) was placed. The sheet was press-vulcanized at a surface pressure of 2 MPa and 150°C for 60 minutes to prepare a vulcanized adhesive sample (refer to Figure 3 ). The rubber 11 of the vulcanized adhesive sample and the brass plated wire 12 are clamped, and the brass plated wire 12 is peeled off in the direction of arrow X according to the T-type peeling test of JIS K 6256, and the coverage of the rubber 11 on the surface of the brass plated wire 12 is measured. The higher the coverage, the better the adhesion between the rubber 11 and the brass plated wire 12. In addition, as the brass plated wire 12, a brass plated wire manufactured by TOKUSEN Co., Ltd. (electroplating, plating composition: Cu / Zn=65 / 35% by weight, plating adhesion: 4 g / kg) was used.

[0136] Then, when the coverage rate of the rubber on the wire surface was 80% or more, it was evaluated as "○ (very good)", and when the coverage rate of the rubber on the wire surface was less than 80%, it was evaluated as "× (poor)".

[0137] Initial Physical Properties

[0138] The rubber composition was press-vulcanized at 150°C for 60 minutes to prepare a rubber sheet (100 mm×100 mm, 2 mm thick). The rubber sheet was subjected to a test of tensile stress (M) at 25°C in accordance with JIS K 6251. 100 ) for determination.

[0139] Then, the tensile stress (M 100 ) was 3.0 MPa or more and was evaluated as "○ (very good)". 100 ) was less than 3.0 MPa and was evaluated as "× (poor)".

[0140] Table 1

[0141] (parts by weight)

[0142]

[0143] Table 2

[0144] (parts by weight)

[0145]

[0146] From the results in Table 1 and Table 2, it can be seen that the rubber composition of the embodiment has a high coverage rate of rubber on the surface of the brass plated wire, and the adhesion between the rubber and the brass plated wire is good. 100 ) is 3.0 MPa or more, resulting in excellent initial physical properties.

[0147] In contrast, the amount of plasticizer in the rubber compositions of Comparative Examples 1 to 6 deviates from the range specified in the present invention, resulting in poor adhesion and other properties. The rubber composition of Comparative Example 7 uses carbon black having a large nitrogen adsorption specific surface area, resulting in the inability to obtain the desired adhesion. The amount of carbon black in the rubber compositions of Comparative Examples 8 and 9 deviates from the range specified in the present invention, resulting in poor adhesion and other properties. The amount of insoluble sulfur and soluble sulfur in the rubber compositions of Comparative Examples 10 to 13 deviates from the range specified in the present invention, resulting in poor adhesion and initial physical properties.

[0148] Furthermore, in the sample for evaluating the adhesion between rubber and brass plated wire using the rubber composition of the example, when the peak intensity of sulfur element measured by energy dispersive X-ray analysis (EDX) at a site within a range of 50 μm from the contact surface with the brass plated wire and the peak intensity of sulfur element measured at a site outside the above range in the rubber were measured under the following conditions, it was confirmed that the peak intensity of sulfur element was higher at the site within a range of 50 μm from the contact surface with the brass plated wire.

[0149] 《Energy dispersive X-ray analysis (EDX) measurement conditions》

[0150] Cross-section processing: ion milling

[0151] ·Analysis and measurement conditions

[0152] Device name: Scanning electron microscope S-4800 (manufactured by Hitachi High-Technologies Corporation)

[0153] Energy dispersive X-ray microanalyzer X-Max (manufactured by Horiba, Ltd.)

[0154] Image type: reflected electron image

[0155] Accelerating voltage: 15 kV

[0156] Conductive treatment: C evaporation

[0157] Magnification:×100k

[0158] Element type: Sulfur

[0159] In addition, Figure 1 , Figure 2In the high-pressure hose having the layer structure shown, when the rubber composition of the embodiment is used as the material for forming the intermediate rubber layer, strong adhesion between the reinforcement layer (plated wire reinforcement layer) and the intermediate rubber layer can be achieved even without an adhesive, and the hose physical properties as a high-pressure hose are excellent.

[0160] In addition, although the above-mentioned embodiments show specific aspects of the present invention, the above-mentioned embodiments are merely examples and are not to be interpreted as limiting. Various modifications that are obvious to those skilled in the art are intended to be included in the scope of the present invention.

[0161] Industrial Applicability

[0162] The rubber composition for coating a plated wire reinforcement layer of the present invention can be used for various oil transport hoses having a plated wire reinforcement layer, such as high-pressure hydraulic hoses for construction machinery (construction machinery), mining (excavation) machinery, and industrial vehicles (forklifts, unmanned transport vehicles, etc.), and engine oil hoses for automobiles.

Claims

1. A rubber composition for coating a plated wire reinforcement layer, the rubber composition being used for coating the periphery of a reinforcement layer in a high-pressure hose having a reinforcement layer composed of a plated wire, characterized in that: The rubber composition for coating the plated wire reinforcement layer is composed of a diene rubber composition, wherein the diene rubber composition contains the following components (A) to (E), and the content ratio is 5 to 20 parts by weight of the component (B), 0.2 to 4.8 parts by weight of the component (C), 0.2 to 4.8 parts by weight of the component (D), and 40 to 100 parts by weight of the component (E), with respect to 100 parts by weight of the component (A). The total amount of the components (C) and (D) is 1.0 to 6.0 parts by weight. (A) diene rubber, (B) plasticizers, (C) insoluble sulfur, (D) Soluble sulfur, (E) Nitrogen adsorption specific surface area is 20m 2 / g or more and 56m 2 / g or less carbon black, The (C) insoluble sulfur refers to sulfur that is 90% by weight or more insoluble in carbon disulfide, and the (D) soluble sulfur refers to sulfur that is 99.5% by weight or more soluble in carbon disulfide.

2. The rubber composition for coating a plated wire reinforcement layer according to claim 1, wherein: The plasticizer (B) is at least one selected from the group consisting of aromatic oils, ether-ester plasticizers, and process oils.

3. The rubber composition for coating a plated wire reinforcement layer according to claim 1, wherein: The diene rubber (A) is styrene butadiene rubber, and the plasticizer (B) is aromatic oil.

4. The rubber composition for coating a plated wire reinforcement layer according to claim 1, wherein: The diene rubber (A) is acrylonitrile butadiene rubber, and the plasticizer (B) is an ether ester plasticizer.

5. The rubber composition for coating a plated wire reinforcement layer according to claim 1 or 2, wherein: The diene rubber (A) is a styrene-butadiene rubber containing 10 to 25% by weight of styrene.

6. The rubber composition for coating a plated wire reinforcement layer according to claim 1 or 2, wherein: The diene rubber (A) is an acrylonitrile-butadiene rubber containing 10 to 33% by weight of acrylonitrile.

7. A high pressure hose, characterized in that: The high-pressure hose comprises: a rubber layer composed of the rubber composition for coating a plated wire reinforcement layer according to any one of claims 1 to 6; and a plated wire reinforcement layer embedded in the rubber layer.

8. A high pressure hose, characterized in that: The high-pressure hose comprises: a rubber layer composed of the rubber composition for coating a plated wire reinforcement layer according to any one of claims 1 to 6; and a plated wire reinforcement layer laminated on at least one of an inner peripheral surface and an outer peripheral surface of the rubber layer.

9. The high-pressure hose according to claim 7 or 8, wherein: The peak intensity of sulfur measured by energy dispersive X-ray analysis at a portion of the rubber layer within a range of 50 μm from a contact surface with the plated wire reinforcement layer is higher than the peak intensity of sulfur measured at a portion of the rubber layer outside the range.

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