JP2022026041A - Rubber composition for covering plated wire reinforcement layer and high-pressure hose therewith - Google Patents

Abstract

To provide a rubber composition for covering a plated wire reinforcement layer which does not damage rubber physical property and is excellent in adhesion with a reinforcement layer made of a plated wire without using an adhesive agent and a high-pressure hose therewith.SOLUTION: A problem is solved by a rubber composition for covering a plated wire reinforcement layer made of a diene-based rubber composition that contains the following components (A) to (E), with respect to 100 pts.wt. of (A) component, 5 to 20 pts.wt. of a (B) component, 0.2 to 4.8 pts.wt. of (C) component, 0.2 to 4.8 pts.wt. of (D) component, 40 to 100 pts.wt. of (E) component, a total amount of (C) and (D) components of 1.0 to 6.0 pts.wt. (A) Diene system rubber. (B) Plasticizer. (C) Insoluble sulfur. (D) Soluble sulfur. (E) Carbon black having a nitrogen absorption specific surface area of 56 m2/g or smaller.SELECTED DRAWING: None

Description

The present invention is plated, which is used for various oil transport hoses provided with a plated wire reinforcing layer, such as high-pressure hydraulic hoses for construction machinery (construction machinery) and mining machinery, and engine oil hoses for automobiles. It relates to a rubber composition for covering a wire reinforcing layer, and a high-pressure hose using the same.

High-pressure hydraulic hoses used in construction machinery, mining machinery, etc. are usually provided with a wire reinforcing layer so that they can withstand high internal pressure.
As the layer structure of the high-pressure hydraulic hose, for example, a plurality of intermediate rubber layers and wire reinforcing layers are alternately laminated between the inner rubber layer and the outer rubber layer, and the wire reinforcing layer is embedded in the intermediate rubber layer. A layered structure that is designed to be worn is adopted.

As the metal wire constituting the wire reinforcing layer, a plated metal wire (plated wire) is usually used in order to enhance rust prevention.
Then, in order to improve the durability of the high-pressure hydraulic hose, it is necessary to firmly bond the plated wire reinforcing layer formed by braiding the plated wire and the rubber layer (particularly, the intermediate rubber layer) in contact with the plated wire reinforcing layer. That is, if the adhesiveness between the plated wire reinforcing layer and the rubber layer is poor, the wire moves or loosens, which adversely affects the durability.

An adhesive is usually used to firmly bond the plated wire reinforcing layer and the rubber layer as described above, but this method has a problem that the manufacturing process becomes complicated.
In order to improve the adhesiveness with the plated wire reinforcing layer without using an adhesive (adhesive-less), for example, a diene-based rubber composition is used as the rubber layer material, and the diene-based rubber composition is used. Although it is considered to increase the amount of sulfur compounded, this method is not realistic because a large amount of sulfur compounded causes many cross-linking points to be formed in the rubber and the heat resistance is lowered.
Therefore, in order to obtain good adhesiveness with a blending amount of sulfur that can maintain heat resistance, for example, a phenol resin, a maleic anhydride-modified polymer, or the like may be added to the rubber layer material, or vulcanization in the rubber layer material. Various methods such as improving the accelerator have been studied (see, for example, Patent Documents 1 to 3).

Japanese Unexamined Patent Publication No. 58-72436 Japanese Unexamined Patent Publication No. 2010-254876 Japanese Unexamined Patent Publication No. 2014-152611

However, with the existing methods as described above, there are many problems such as a problem that the rubber hardness increases too much and causes a decrease in fatigue resistance, and a problem that an increase in tackiness adversely affects workability and product appearance. Occurs. For this reason, it is desired to obtain an effect of improving the adhesiveness to the plated wire reinforcing layer by a method different from the existing method without impairing the physical characteristics of the rubber.

The present invention has been made in view of such circumstances, and is a rubber for covering a plated wire reinforcing layer, which has excellent adhesiveness to a reinforcing layer made of a plated wire without impairing the physical properties of the rubber and without using an adhesive. It is an object of the present invention to provide a composition and a high-pressure hose using the composition.

The present inventors have conducted intensive studies to solve the above-mentioned problems. In the process of the research, the present inventors used a diene-based rubber composition as an intermediate rubber layer material for a high-pressure hose, and further studied various studies focusing on the type and blending amount of sulfur in the rubber layer material. went. As described above, simply increasing the blending amount of sulfur in the rubber layer material improves the adhesiveness with the plated wire reinforcing layer, but causes a problem that the rubber physical properties are deteriorated. Therefore, the present inventors use sulfur mainly contributing to the adhesiveness to the plated wire reinforcing layer and sulfur mainly contributing to the vulcanization of rubber in combination to fully exert the functions of each sulfur. We considered achieving the intended purpose by reducing the overall amount of sulfur.
As a result of conducting various experiments, the plasticizer (B), the insoluble sulfur (C), the soluble sulfur (D), and the carbon having a specific surface area of 56 m ² / g or less with respect to the diene rubber (A). When black (E) is blended in a specific ratio, the soluble sulfur (D) having a cyclic structure and being activated at an early stage has a small specific surface area (nitrogen adsorption specific surface area of 56 m ² / g or less). The polymer-like insoluble sulfur (C), which contributes to vulcanization while being influenced by carbon black (E) and is not easily affected by the specific carbon black (E), acts as a plasticizer (B). As a result, it has become easier to be extruded from the rubber composition in which vulcanization progresses and gather near the surface of the plated wire. At the same time, the insoluble sulfur (C) is activated later than the soluble sulfur (D) and reacts with the plating component (for example, copper) on the surface of the plating wire to form an adhesive layer between the plating component and sulfur. By doing so, it was found that the adhesiveness was developed. From this, it is possible to achieve the intended purpose because the adhesiveness with the plated wire is strong, the vulcanization of the rubber is sufficient, and the physical characteristics of the rubber are good, while suppressing the overall amount of sulfur. Found and reached the present invention.

That is, in order to achieve the above object, the present invention has the following [1] to [9] as its gist.
[1] A rubber composition used for covering the periphery of the reinforcing layer in a high-pressure hose provided with a reinforcing layer made of a plated wire, which contains the following components (A) to (E) and (A). ) Component (B) is 5 to 20 parts by weight, component (C) is 0.2 to 4.8 parts by weight, and component (D) is 0.2 to 4.8 parts by weight, based on 100 parts by weight of the component. Plating comprising a diene-based rubber composition in which the component (E) is 40 to 100 parts by weight and the total amount of the components (C) and (D) is 1.0 to 6.0 parts by weight. A rubber composition for coating a wire reinforcing layer.
(A) Diene rubber.
(B) Plasticizer.
(C) Insoluble sulfur.
(D) Soluble sulfur.
(E) Carbon black having a nitrogen adsorption specific surface area of 56 m ² / g or less.
[2] The rubber for coating a plated wire reinforcing layer according to [1], wherein the plasticizer (B) is at least one selected from the group consisting of an aroma-based oil, an ether ester-based plasticizer, and a process oil. Composition.
[3] The rubber composition for coating a plated wire reinforcing layer according to [1], wherein the diene-based rubber (A) is styrene-butadiene rubber and the plasticizer (B) is an aroma-based oil.
[4] The rubber composition for coating a plated wire reinforcing layer according to [1], wherein the diene-based rubber (A) is an acrylonitrile butadiene rubber and the plasticizer (B) is an ether ester-based plasticizer.
[5] The rubber composition for coating a plated wire reinforcing layer according to [1] or [2], wherein the diene-based rubber (A) is a styrene-butadiene rubber having a styrene content of 10 to 25% by weight.
[6] The rubber composition for coating a plated wire reinforcing layer according to [1] or [2], wherein the diene-based rubber (A) is an acrylonitrile butadiene rubber having an acrylonitrile content of 10 to 33% by weight.
[7] A rubber layer made of the rubber composition for covering the plated wire reinforcing layer according to any one of [1] to [6] and a plated wire reinforcing layer are provided, and the plated wire reinforcing layer is the rubber. A high pressure hose characterized by being embedded in a layer.
[8] A rubber layer made of the rubber composition for covering the plated wire reinforcing layer according to any one of [1] to [6] and a plated wire reinforcing layer are provided, and the plated wire reinforcing layer is the rubber. A high-pressure hose that is laminated on at least one of the inner peripheral surface and the outer peripheral surface of the layer.
[9] The peak intensity of the sulfur element measured by the energy dispersive X-ray analysis method (EDX) in the rubber layer within a range of 50 μm from the contact surface with the plated wire reinforcing layer is the rubber. The high pressure hose according to [7] or [8], which is higher than the peak intensity of sulfur element measured at a location outside the above range in the layer.

From the above, the rubber composition for covering the plated wire reinforcing layer of the present invention can enhance the adhesiveness to the reinforcing layer made of the plated wire without impairing the rubber physical properties and without using an adhesive. As a result, excellent performance can be exhibited as a rubber layer material (particularly an intermediate layer material) of a high-pressure hose.

It is a schematic diagram which shows an example of the high pressure hose of this invention. It is a schematic diagram which shows another example of the high pressure hose of this invention. It is explanatory drawing which shows the peeling test in the adhesiveness evaluation of a rubber and a brass-plated wire.

Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

As described above, the rubber composition for coating the plated wire reinforcing layer of the present invention is a rubber composition used for coating the periphery of the reinforcing layer in a high-pressure hose provided with the reinforcing layer made of plated wire. It contains the following components (A) to (E), and the component (B) is 5 to 20 parts by weight and the component (C) is 0.2 to 4.8 parts by weight with respect to 100 parts by weight of the component (A). Parts by weight, component (D) 0.2 to 4.8 parts by weight, component (E) 40 to 100 parts by weight, total amount of components (C) and (D) 1.0 to 6.0 parts by weight It is composed of a diene rubber composition having a content ratio of.
(A) Diene rubber.
(B) Plasticizer.
(C) Insoluble sulfur.
(D) Soluble sulfur.
(E) Carbon black having a nitrogen adsorption specific surface area of 56 m ² / g or less.

In the present invention, the insoluble sulfur (C) refers to sulfur that is 90% by weight or more insoluble with respect to carbon disulfide, and the insoluble sulfur (C) is preferably 95% by weight with respect to carbon disulfide. %, More preferably 98% by weight or more insoluble. Further, the soluble sulfur (D) refers to sulfur exhibiting solubility of 99.5% by weight or more with respect to carbon disulfide, and the soluble sulfur (D) is preferably 99. With respect to carbon disulfide. It exhibits a solubility of 9% by weight or more, more preferably 100% by weight.

Details of each component in the rubber composition for coating the plated wire reinforcing layer of the present invention will be described below.

<< 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, NBR is preferable when oil resistance is required, and SBR and NR are preferable when wear resistance is required.
The NBR is preferably an NBR having an acrylonitrile amount (AN amount) of 10 to 33% by weight, more preferably an AN amount of 10 to 28% by weight, from the viewpoint of adhesiveness to the reinforcing layer made of plated wire. NBR. That is, if the amount of AN is too large, the vulcanization rate becomes high, the bond between the polymers becomes strong, and sulfur is difficult to elute on the surface, which may cause a decrease in adhesiveness, and the amount of AN is too small. This is because the initial characteristics may be lowered.
Further, the SBR is preferably an SBR having a styrene content of 10 to 25% by weight, more preferably an SBR having a styrene content of 15 to 25% by weight, from the viewpoint of adhesiveness to the reinforcing layer made of plated wire. .. That is, if the amount of styrene is too large, the vulcanization rate becomes high, the bond between the polymers becomes strong, and sulfur is difficult to elute on the surface, which may cause a decrease in adhesiveness, and the amount of styrene is too small. This is because the initial characteristics may be lowered.

<< Plasticizer (B) >>
Examples of the plasticizer (B) include aroma-based oils, ether ester-based plasticizers, process oils, and the like.
Here, examples of the aroma-based oil include Diana Process AC-12, Diana Process AC-460, Diana Process AH-16 (all manufactured by Idemitsu Showa Shell Co., Ltd.), and JSO Aroma 790 (manufactured by Nippon Sun Oil Co., Ltd.). Aromax 1 and Aromax 3 (all manufactured by Fuji Kosan Co., Ltd.) can be mentioned.
The ether ester-based plasticizer is a plasticizer having both an ether bond and an ester bond in one molecule, specifically, bis (2- (2-butoxyethoxy) ethyl] adipic acid such as bis (2- (2-butoxyethoxy) ethyl] adipate. Examples include ether ester plasticizers.
Examples of the process oil include naphthenic oil and paraffin oil.
And these are used alone or in combination of two or more.

When the diene-based rubber (A) is styrene-butadiene rubber and the plasticizer (B) is an aroma-based oil, the diene-based rubber (A) and the plasticizer (B) have excellent compatibility. Therefore, it is preferable.
Further, even when the diene-based rubber (A) is an acrylonitrile butadiene rubber and the plasticizer (B) is an ether ester-based plasticizer, the diene-based rubber (A) and the plasticizer (B) are compatible with each other. It is preferable because it becomes excellent.

The content of the plasticizer (B) with respect to 100 parts by weight of the diene rubber (A) is in the range of 5 to 20 parts by weight, preferably in the range of 5 to 18 parts by weight, more preferably in the range of 5 to 18 parts by weight as described above. Is in the range of 8 to 15 parts by weight. That is, if the content of the plasticizer (B) is too small, the bleeding of the insoluble sulfur (C) is reduced and the adhesive effect with the plated wire cannot be sufficiently obtained, so that the plasticizer (B) is contained. This is because if the amount is too large, the physical properties of the rubber may be deteriorated, the adhesiveness of the plasticizer (B) may be deteriorated due to bleeding, and the like.

<< Insoluble sulfur (C) >>
Examples of the insoluble sulfur (C) include polymer-like 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 as described above include Sanfel (manufactured by Sanshin Chemical Co., Ltd.) and Sanfel EX (manufactured by Sanshin Chemical Co., Ltd.).
The content of the insoluble sulfur (C) with respect to 100 parts by weight of the diene rubber (A) is in the range of 0.2 to 4.8 parts by weight as described above, preferably 0.5 to 0.5 parts by weight. The range is 4.5 parts by weight, more preferably 1.0 to 3.5 parts by weight. That is, if the content of the insoluble sulfur (C) is too small, the adhesive effect with the plated wire cannot be sufficiently obtained, and if the content of the insoluble sulfur (C) is too large, a large amount that does not react with the plated wire is obtained. This is because insoluble sulfur may elute on the surface and hinder the adhesive effect with the plated wire.

<< Soluble sulfur (D) >>
Examples of the soluble sulfur (D) 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 as described above include Kinkain fine powder 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 (D) with respect to 100 parts by weight of the diene rubber (A) is in the range of 0.2 to 4.8 parts by weight as described above, preferably 0.5 to 0.5 parts by weight. The range is 4.5 parts by weight, more preferably 1.0 to 3.5 parts by weight. That is, if the content of the soluble sulfur (D) is too small, the rubber is not sufficiently vulcanized, resulting in inferior rubber physical properties. If the content of the soluble sulfur (D) is too large, before vulcanization. This is because soluble sulfur blooms on the rubber surface of the rubber, which may hinder the adhesive effect with the plated wire.

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 as described above with respect to 100 parts by weight of the diene rubber (A). Yes, preferably in the range of 1.0 to 5.0 parts by weight, more preferably in the range of 1.5 to 4.0 parts by weight. That is, within such a range, vulcanization and the like can be performed satisfactorily without deterioration of heat resistance and the like.

《Carbon Black (E)》
As the carbon black, as described above, carbon black (E) having a nitrogen adsorption specific surface area of 56 m ² / g or less is used. From the viewpoint of further enhancing the vulcanization effect of the rubber composition by the soluble sulfur (D), carbon black having a nitrogen adsorption specific surface area of 20 to 50 m ² / g is preferable, and a nitrogen adsorption specific surface area of 25 is more preferable. ~ 45m ² / g of carbon black is used. The nitrogen adsorption specific surface area is defined in JIS K 6217, and means the nitrogen adsorption specific surface area per unit weight (m ² / g). Specific examples of the carbon black as described above 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.
The content of the specific carbon black (E) with respect to 100 parts by weight of the diene rubber (A) is in the range of 40 to 100 parts by weight, preferably 50 to 90 parts by weight, as described above. The range, more preferably 60 to 90 parts by weight. That is, if the content of the specific carbon black (E) is too small, the effect of enhancing the vulcanization of the rubber composition by the soluble sulfur (D) and the effect of enhancing the adhesion to the plated wire by the insoluble sulfur (C) are obtained. If it is not sufficiently obtained and the content of the specific carbon black (E) is too large, vulcanization is activated and insoluble sulfur is also used for vulcanization, which may hinder the adhesion effect with the plated wire. Because there is.

In addition to the above components (A) to (E), the rubber composition for coating the plated wire reinforcing layer of the present invention contains any material such as zinc oxide, stearic acid, silica, a processing aid, and a vulcanization accelerator. It may be blended as needed.

In the rubber composition, for example, the above-mentioned components (A) to (E) and various optional materials as described above are appropriately blended, and these are kneaded with a kneader, a roll, a Banbury mixer or the like. It can be prepared by kneading with.

As described above, the rubber composition for covering the plated wire reinforcing layer of the present invention is a rubber composition used for covering the periphery of the reinforcing layer in a high-pressure hose provided with the reinforcing layer made of plated wire. be.
Examples of the high-pressure hose include those shown in the following (1) and (2).
(1) A high-pressure hose comprising a rubber layer made of the rubber composition for covering a plated wire reinforcing layer of the present invention and a plated wire reinforcing layer, wherein the plated wire reinforcing layer is embedded in the rubber layer. ..
(2) A rubber layer made of the rubber composition for covering the plated wire reinforcing layer of the present invention and a plated wire reinforcing layer are provided, and the plated wire reinforcing layer is at least the inner peripheral surface and the outer peripheral surface of the rubber layer. High pressure hose laminated on one side.

Here, in the high-pressure hose shown in FIG. 1, an intermediate rubber layer 2a is formed on the outer peripheral surface of the inner rubber layer 1, and a reinforcing layer 3 made of a plated wire is formed on the outer peripheral surface of the intermediate rubber layer 2a. The intermediate rubber layer 2b is formed on the outer peripheral surface of the intermediate rubber layer 2, and the outer surface rubber layer 4 is formed on the outer peripheral surface of the intermediate rubber layer 2b. Then, by forming the intermediate rubber layers 2a and 2b into a layer made of the rubber composition for covering the plated wire reinforcing layer of the present invention, the high-pressure hose of the aspect shown in the above (1) can be obtained.

Further, in the high-pressure hose shown in FIG. 2, the intermediate rubber layer 2 is formed on the outer peripheral surface of the reinforcing layer 13a made of the plated wire, and the reinforcing layer 13b made of the plated wire is formed on the outer peripheral surface of the intermediate rubber layer 2. Is. Then, by forming the intermediate rubber layer 2 as a layer made of the rubber composition for covering the plated wire reinforcing layer of the present invention, the high-pressure hose according to the above (2) can be obtained.

The high-pressure hose of the present invention is not limited to the layer structure shown in FIGS. 1 and 2 as long as it has a laminated structure in which the intermediate rubber layer and the reinforcing layer are alternately and repeatedly laminated. , 2 layers of intermediate rubber layer / reinforcing layer, 4 layers (intermediate rubber layer / reinforcing layer / intermediate rubber layer / reinforcing layer), 6 layers (intermediate rubber layer / reinforcing layer / intermediate rubber layer / reinforcing layer / intermediate rubber layer / A hose having a laminated structure such as a reinforcing layer) and eight layers (intermediate rubber layer / reinforcing layer / intermediate rubber layer / reinforcing layer / intermediate rubber layer / reinforcing layer / intermediate rubber layer / reinforcing layer) may be used.

Further, the peak intensity of the sulfur element measured by the energy dispersive X-ray analysis method (EDX) in the range of 50 μm from the contact surface with the reinforcing layer (plated wire reinforcing layer) in the intermediate rubber layer. However, it is preferable that the intensity is higher than the peak intensity of the sulfur element measured at a portion outside the above range in the intermediate rubber layer. That is, in the case of the above, the adhesive layer is well formed in the intermediate rubber layer by the contact reaction of the reinforcing layer with the plating, and the adhesiveness is well developed.
The measurement conditions of the energy dispersive X-ray analysis method (EDX) can be, for example, the following conditions.
≪Energy dispersive X-ray analysis method (EDX) measurement conditions≫
・ Cross section processing: Ion milling method ・ Analytical measurement conditions Device name: Scanning electron microscope S-4800 (manufactured by Hitachi High-Tech)
Energy Dispersive X-ray Microanalyzer X-Max (manufactured by HORIBA, Ltd.)
Image type: Reflected electron image Acceleration voltage: 15kV
Conductionization treatment: C vapor deposition Magnification: × 100k
Elemental species: Sulfur

Further, in the present invention, from the viewpoint of durability and flexibility, the intermediate rubber layer preferably has a tensile stress (M ₁₀₀ ) of 3.0 MPa or more in an atmosphere of 25 ° C., more preferably 3.0 to. It is 6.0 MPa, more preferably 3.5 to 5.0 MPa or less.
The tensile stress (M ₁₀₀ ) can be measured according to, for example, JIS K 6251.

The reinforcing layer is a layer formed by braiding plated wires into a blade shape, a spiral shape, or the like in order to reinforce the strength of the entire hose.
Examples of the plating treatment in the plated wire include copper plating, zinc plating, brass (copper-zinc alloy) plating, nickel plating, tin plating, cobalt plating and the like, and brass plating is preferable.
The diameter of the plated wire is usually in the range of 0.15 to 1.00 mm, preferably in the range of 0.20 to 0.80 mm.

When the inner surface rubber layer 1 is formed as in the high-pressure hose shown in FIG. 1, rubber having excellent oil resistance is preferable as the material, for example, acrylic nitrile butadiene rubber (NBR) and hydrogenated acrylic nitrile butadiene rubber (HNBR). ), Acrylic rubber (ACM), ethylene acrylate rubber (AEM), chlorinated polyethylene (CM), chlorosulfonated polyethylene (CSM), fluororubber (FKM) and the like. These may be used alone or in combination of two or more. Among these, NBR is preferable from the viewpoint of oil resistance, strength, and cost.
In addition to rubber such as NBR, the rubber composition for forming the inner surface rubber layer 1 includes a reinforcing material (carbon black, etc.), a white filler, a plasticizer, stearate, zinc white, a vulcanizing agent, and vulcanization. Accelerators, processing aids, etc. may be added as needed.

Further, when the outer surface rubber layer 4 is formed as in the high-pressure hose shown in FIG. 1, rubber having excellent weather resistance is preferable as the material thereof, for example, chloroprene rubber (CR), styrene butadiene rubber (SBR), ethylene. -Styrene-diene rubber (EPDM), SBR and EPDM blended rubber, NBR and EPDM blended rubber, NBR and vinyl chloride (PVC) blended rubber, acrylic rubber (ACM), ethylene acrylate rubber (AEM), chlorinated Examples thereof include polyethylene (CM) and chlorosulfonated polyethylene (CSM). These may be used alone or in combination of two or more. Among these, CR is preferable from the viewpoint of weather resistance, cost, and oil resistance.
In addition to rubber such as CR, the rubber composition for forming the outer surface rubber layer 4 includes a reinforcing material (carbon black, etc.), a white filler, a plasticizer, stearate, zinc oxide, and an acid receiving agent (high activity). (Magnet oxide, hydrotalcite, etc.), anti-aging agent, vulcanization agent, vulcanization accelerator, processing aid, etc. may be appropriately added as necessary.

The high-pressure hose of the present invention shown in FIG. 1 can be manufactured, 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 the 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 the intermediate rubber layer 2a. Subsequently, a plated wire such as a brass-plated wire is spirally knitted on the outer peripheral surface of the intermediate rubber layer 2a to form the reinforcing layer 3. Then, the rubber composition for forming the intermediate rubber layer is extruded on the outer peripheral surface of the reinforcing layer 3 to form the intermediate rubber layer 2b. Further, 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 the outer surface rubber layer 4. Finally, the laminated body is vulcanized (steam vulcanization, etc.) under predetermined conditions (for example, 140 to 170 ° C. × 10 to 60 minutes) to obtain a high-pressure hose having a layered structure as shown in FIG. Can be produced.

The high-pressure hose of the present invention is not limited to the layer structure as shown in FIG. 1, and as described above, the hose having the layer structure shown in FIG. 2 or an intermediate rubber layer and a reinforcing layer are alternately arranged in large numbers. It does not matter even if it is a laminated structure.

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

The thickness of the inner rubber layer 1 is usually in the range of 0.7 to 4.0 mm, preferably 1.0 to 3.0 mm, and the thickness of the entire intermediate rubber layer is 0.1 to 0.5 mm. The range is preferable, particularly preferably 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. Is.

Next, Examples will be described together with Comparative Examples. However, the present invention is not limited to these examples.

First, the materials shown below were prepared prior to Examples and Comparative Examples.

[SBR]
Toughden 1000, manufactured by Asahi Kasei, styrene amount: 18% by weight

[NBR]
Nipole DN302, Zeon Corporation, AN amount: 28% by weight

[NR]
RSS # 3

[Plasticizer (i)]
Aroma oil (Diana Process AC-12, manufactured by Idemitsu Showa Shell)

[Plasticizer (ii)]
Ether ester oil (ADEKA Sizer RS-107, manufactured by ADEKA)

[Plasticizer (iii)]
Paraffin oil (Diana Process NM-280, manufactured by Idemitsu Kosan Co., Ltd.)

[Carbon black (i)]
Seest SO, manufactured by Tokai Carbon Co., Ltd., Nitrogen adsorption specific surface area: 42 m ² / g

[Carbon black (ii)]
Seest 116HM, manufactured by Tokai Carbon Co., Ltd., nitrogen adsorption specific surface area: 56m ² / g

[Carbon black (iii)]
Seest 300, manufactured by Tokai Carbon Co., Ltd., nitrogen adsorption specific surface area: 84 m ² / g

[Insoluble sulfur]
Sanfel, manufactured by Sanshin Kagaku Co., Ltd.

[Soluble sulfur]
Jinhua Brand Fine Sulfur, manufactured by Tsurumi Chemical Industry Co., Ltd.

[Examples 1 to 16, Comparative Examples 1 to 13]
The components shown in Tables 1 and 2 below were blended in the proportions shown in the same table, and these were kneaded using a 3 L kneader to prepare a rubber composition.

The rubber compositions of Examples and Comparative Examples thus obtained were used to evaluate the following properties. The results are also shown in Tables 1 and 2 below.

≪Adhesiveness≫
Using the above rubber composition, an unvulcanized rubber sheet (100 mm × 100 mm, thickness 2 mm) is prepared, and one brass-plated wire (wire diameter 0.4 mm, length 300 mm) is placed on the rubber sheet. ) Was placed. This was press-vulcanized at a surface pressure of 2 MPa at 150 ° C. for 60 minutes to prepare a vulcanized adhesive sample (see FIG. 3). The rubber 11 of this vulture-bonded sample and the brass-plated wire 12 are chucked, and the brass-plated wire 12 is peeled in the arrow X direction in accordance with the T-type peeling test of JIS K 6256, and the surface of the brass-plated wire 12 is peeled. The coverage of the rubber 11 was measured. The higher the coverage, the better the adhesiveness between the rubber 11 and the brass-plated wire 12. As the brass-plated wire 12, a brass-plated wire manufactured by Toxen (electric plating, plating composition: Cu / Zn = 65/35% by weight, plating adhesion amount: 4 g / kg) was used.
Then, the one in which the coverage of the rubber on the wire surface was 80% or more was evaluated as "◯", and the one in which the coverage of the rubber on the wire surface was less than 80% was evaluated as "x".

≪Initial physical characteristics≫
A rubber sheet (100 mm × 100 mm, thickness 2 mm) was prepared by press vulcanizing at 150 ° C. for 60 minutes using the above rubber composition. Using the above rubber sheet, the tensile stress (M ₁₀₀ ) was measured in an atmosphere of 25 ° C. according to JIS K 6251.
Then, the tensile stress (M ₁₀₀ ) of 3.0 MPa or more was evaluated as “◯”, and the tensile stress (M ₁₀₀ ) of less than 3.0 MPa was evaluated as “x”.

From the results of Tables 1 and 2 above, the rubber composition of the example had a high coverage of rubber on the surface of the brass-plated wire, and the adhesiveness between the rubber and the brass-plated wire was good. Further, the tensile stress (M ₁₀₀ ) was 3.0 MPa or more, and the initial physical properties were also excellent.

On the other hand, in the rubber compositions of Comparative Examples 1 to 6, the amount of the plasticizer was out of the range specified in the present invention, resulting in inferior adhesiveness and the like. The rubber composition of Comparative Example 7 used carbon black having a large nitrogen adsorption specific surface area, and the result was that the desired adhesiveness could not be obtained. In the rubber compositions of Comparative Examples 8 and 9, the amount of carbon black was out of the range specified in the present invention, resulting in inferior adhesiveness and the like. In the rubber compositions of Comparative Examples 10 to 13, the amounts of insoluble sulfur and soluble sulfur were out of the specified range of the present invention, resulting in inferior adhesiveness or initial physical properties.

In the sample used for evaluating the adhesiveness between the rubber and the brass-plated wire using the rubber composition of the example, the energy dispersive X is located within the range of 50 μm from the contact surface with the brass-plated wire. When the peak intensity of the sulfur element measured by the line analysis method (EDX) and the peak intensity of the sulfur element measured at a place outside the above range in the rubber were measured under the following conditions, the brass-plated wire was obtained. It was confirmed that the peak intensity of the sulfur element was higher in the range from the contact surface to 50 μm.
≪Energy dispersive X-ray analysis method (EDX) measurement conditions≫
・ Cross section processing: Ion milling method ・ Analytical measurement conditions Device name: Scanning electron microscope S-4800 (manufactured by Hitachi High-Tech)
Energy Dispersive X-ray Microanalyzer X-Max (manufactured by HORIBA, Ltd.)
Image type: Reflected electron image Acceleration voltage: 15kV
Conductionization treatment: C vapor deposition Magnification: × 100k
Elemental species: Sulfur

Further, in the high-pressure hose having the layer structure shown in FIGS. 1 and 2, when the rubber composition of the example was used as the material for forming the intermediate rubber layer, the reinforcing layer (plated wire reinforcement) was used even without an adhesive. The layer) and the intermediate rubber layer were strongly adhered to each other, and the hose had excellent physical properties as a high-pressure hose.

The rubber composition for coating a plated wire reinforcing layer of the present invention is a high-pressure hydraulic hose for construction machinery (construction machinery), mining machinery, industrial vehicles (forklifts, unmanned transport vehicles, etc.), and engine oil hoses for automobiles. It can be used for various oil transport hoses and the like provided with a plated wire reinforcing layer.

Claims (9)

A rubber composition used for covering the periphery of the reinforcing layer in a high-pressure hose provided with a reinforcing layer made of a plated wire, which contains the following components (A) to (E) and contains the following components (A) to (E), and the component (A) 100. The component (B) is 5 to 20 parts by weight, the component (C) is 0.2 to 4.8 parts by weight, the component (D) is 0.2 to 4.8 parts by weight, and (E). A plated wire reinforcing layer comprising a diene-based rubber composition having a content of 40 to 100 parts by weight and a total amount of (C) and (D) components of 1.0 to 6.0 parts by weight. Rubber composition for coating.
(A) Diene rubber.
(B) Plasticizer.
(C) Insoluble sulfur.
(D) Soluble sulfur.
(E) Carbon black having a nitrogen adsorption specific surface area of 56 m ² / g or less. The rubber composition for coating a plated wire reinforcing layer according to claim 1, wherein the plasticizer (B) is at least one selected from the group consisting of an aroma oil, an ether ester plasticizer, and a process oil. The rubber composition for coating a plated wire reinforcing layer according to claim 1, wherein the diene-based rubber (A) is styrene-butadiene rubber and the plasticizer (B) is an aroma-based oil. The rubber composition for coating a plated wire reinforcing layer according to claim 1, wherein the diene-based rubber (A) is an acrylonitrile butadiene rubber and the plasticizer (B) is an ether ester-based plasticizer. The rubber composition for coating a plated wire reinforcing layer according to claim 1 or 2, wherein the diene-based rubber (A) is a styrene-butadiene rubber having a styrene content of 10 to 25% by weight. The rubber composition for coating a plated wire reinforcing layer according to claim 1 or 2, wherein the diene-based rubber (A) is an acrylonitrile butadiene rubber having an acrylonitrile content of 10 to 33% by weight. A rubber layer made of the rubber composition for covering the plated wire reinforcing layer according to any one of claims 1 to 6 and a plated wire reinforcing layer are provided, and the plated wire reinforcing layer is contained in the rubber layer. A high-pressure hose characterized by being buried. A rubber layer made of the rubber composition for coating the plated wire reinforcing layer according to any one of claims 1 to 6 and a plated wire reinforcing layer are provided, and the plated wire reinforcing layer is included in the rubber layer. A high-pressure hose that is laminated on at least one of a peripheral surface and an outer peripheral surface. The peak intensity of the sulfur element measured by the energy dispersive X-ray analysis method (EDX) in the rubber layer within a range of 50 μm from the contact surface with the plated wire reinforcing layer is the above rubber layer. The high pressure hose according to claim 7 or 8, which is higher than the peak intensity of sulfur element measured at a location outside the range.

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