JP2002005345A - Heat-resistant high-pressure hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-resistant high-pressure hose that has the same adhesive property between a reinforcing layer and at least an external rubber layer out of an internal rubber layer and the external rubber layer as an existent high-pressure hose using sulfur-vulcanized rubber. SOLUTION: The heat-resistance high-pressure hose comprises an internal rubber layer 1, a reinforcing layer 2 using steel cord wire formed on the periphery of the internal rubber layer 1, and an external rubber layer 3 formed on the periphery of the reinforcing layer 2. At least the external rubber layer 3 out of the internal and external rubber layers 1 and 3 is formed from peroxide-vulcanized rubber. The external rubber layer 3 and the reinforcing layer 2 are bonded together with an adhesive having both a radical vulcanization-reactive to the rubber of the external rubber layer 3 and a radical reactive to the steel cord wire of the reinforcing layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant high-pressure hose in which a reinforcing layer reinforced by using a steel cord wire is formed between an inner rubber layer and an outer rubber layer.

[0002]

2. Description of the Related Art A conventional rubber hose has a structure in which a reinforcing layer reinforced with a steel cord wire is formed between an inner rubber layer and an outer rubber layer.

[0003]

However, the conventional peroxide-cured rubber hose is inferior in adhesion between the reinforcing layer and the outer rubber layer, so that an air layer is provided between the reinforcing layer and the outer rubber layer. (Air layer) is easily interposed. For this reason, there is a problem that oxidation (rust) of the steel cord wire of the reinforcing layer is promoted by water or high heat when the hose is used, and the hose function is reduced in a short period of time. In addition, since the adhesion between the reinforcing layer and the outer rubber layer is poor, the outer rubber layer swells at the end of the hose (caulked portion),
There is also a drawback that a metal fitting failure occurs.

The present invention has been made in view of such circumstances, and the adhesiveness between the reinforcing layer and at least the outer rubber layer of the inner rubber layer and the outer rubber layer is determined by using a conventional high-pressure sulfur-vulcanized rubber. Its purpose is to provide a heat-resistant high-pressure hose equivalent to a hose.

[0005]

In order to achieve the above object, a heat-resistant high-pressure hose according to the present invention comprises an inner rubber layer and a reinforcing layer formed by using a steel cord wire formed on the outer periphery of the inner rubber layer. And a heat-resistant high-pressure hose comprising an outer rubber layer formed on the outer periphery of the reinforcing layer, wherein at least the outer rubber layer of the inner rubber layer and the outer rubber layer is formed of peroxide-cured rubber. In addition, the outer rubber layer and the reinforcing layer are bonded to each other using an adhesive having both a group that vulcanizes with the rubber of the outer rubber layer and a group that reacts with the steel cord wire of the reinforcing layer. Take the configuration.

That is, the present inventors have conducted intensive studies in order to obtain a heat-resistant high-pressure hose having good adhesion between the reinforcing layer and the outer rubber layer. As a result, the outer rubber layer is formed of peroxide-cured rubber, and an adhesive having both a group that undergoes a vulcanization reaction with the rubber of the outer rubber layer and a group that reacts with the steel cord wire of the reinforcing layer is used. When the interface between the outer rubber layer and the reinforcing layer is adhered, the adhesive shows a chemical bond to both the rubber and the steel cord wire during the vulcanization reaction, and the adhesive strength between the outer rubber layer and the reinforcing layer is improved. The inventors have found that the present invention has been achieved.

[0007] If both the inner rubber layer and the outer rubber layer are formed using peroxide-cured rubber, the inner rubber layer is also chemically bonded to the steel cord wire by the adhesive. And the adhesive strength between the inner rubber layer, the reinforcing layer and the outer rubber layer is improved, and a hose having higher heat resistance can be obtained.

When a silane-based adhesive is used as the adhesive, stable adhesive performance is exhibited in a high-temperature atmosphere and after thermal aging, and the dynamic fatigue durability is improved.

[0009]

Next, embodiments of the present invention will be described in detail.

The heat-resistant high-pressure hose of the present invention is, for example, shown in FIG.
As shown in FIG. 1, an inner rubber layer 1, a reinforcing layer 2 using a steel cord wire formed on the outer periphery of the inner rubber layer 1, and an outer rubber layer 3 formed on the outer periphery of the reinforcing layer 2 It is a structure provided. In the present invention, at least the outer rubber layer 3 of the inner rubber layer 1 and the outer rubber layer 3 is formed of peroxide-cured rubber, and the outer rubber layer 3 and the reinforcing layer 2 The most characteristic feature is that the outer rubber layer 3 is bonded using an adhesive having both a group that undergoes a vulcanization reaction with the rubber and a group that reacts with the steel cord wire of the reinforcing layer 2.

The rubber used as a material for forming the outer rubber layer 3 is not particularly limited as long as the rubber is vulcanized by peroxide (peroxide) (hereinafter referred to as "peroxide vulcanized rubber"). , Chlorinated polyethylene (CP
E), chlorosulfonated polyethylene (CSM), natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SB)
R), acrylonitrile-butadiene copolymer rubber (NB
R), ethylene-propylene copolymer rubber (EPM), ethylene-propylene-diene copolymer rubber (EPDM),
Examples include chloroprene rubber (CR), butyl rubber (IIR), acrylic rubber (ACM), epichlorohydrin rubber, silicone rubber, fluorine rubber, urethane rubber, and the like. These may be used alone or in combination of two or more. Of these, chlorinated polyethylene (CP) is preferred in terms of strength, heat resistance, oil resistance, compression set, and ozone properties.
E) is preferably used.

The peroxide (peroxide) serving as a vulcanizing agent for the peroxide vulcanized rubber is, for example, dicumyl peroxide (DC) represented by the following formula (1).
P), 1,1-bis (tert-butylperoxy)
3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 1,3-bis (tert-butylperoxyisopropyl) benzene, the following formula (2) Benzoyl peroxide, dicumenyl peroxide, represented by 2,
2-di (tert-butylperoxy) butane and the like. These may be used alone or in combination of two or more. Among them, dicumyl peroxide (DCP) is preferably used in terms of low cost and versatility.

[0013]

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[0014]

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The amount of the peroxide is preferably set in the range of 0.1 to 10 parts, more preferably 100 parts by weight (hereinafter abbreviated as "parts") of the peroxide-cured rubber. Is 1.0 to 5.0 parts.

The material for forming the outer rubber layer 3 includes, in addition to peroxide vulcanized rubber and peroxide, processing aids, reinforcing agents, softeners, crosslinking accelerators, antioxidants, co-crosslinking agents. And the like can be appropriately blended and used as necessary.

Examples of the processing aid include stearic acid and the like. Examples of the reinforcing agent include carbon black. As the softener,
For example, process oil, naphthenic oil and the like can be mentioned. Examples of the crosslinking accelerator include MgO, ZnO
And the like. Examples of the antioxidant include a phenylenediamine antioxidant and a phenolic antioxidant. Examples of the co-crosslinking agent include triallyl isocyanurate (TAI)
C) and zinc methacrylate.

The inner rubber layer 1 may be formed of a rubber that has been vulcanized (for example, sulfur vulcanized) other than peroxide vulcanization.
It is preferable to form using the same material as the forming material of the above. As described above, when both the inner rubber layer 1 and the outer rubber layer 3 are formed using the peroxide vulcanized rubber, the inner rubber layer 1 also shows a chemical bond with the steel cord wire by the adhesive, The adhesive strength between the inner rubber layer 1, the reinforcing layer 2, and the outer rubber layer 3 is improved, and a hose having higher heat resistance can be obtained.

The reinforcing layer 2 formed between the inner rubber layer 1 and the outer rubber layer 3 is a layer formed by braiding a steel cord wire into a braided shape, a spiral shape or the like in order to reinforce the strength of the entire hose. It is. The reinforcing layer 2 is not limited to a single-layer structure as shown in FIG.
A multilayer structure of two or more layers may be used.

The above-mentioned steel cord wire is preferably subjected to a plating treatment. Examples of the plating treatment include copper plating, zinc plating, and brass (copper-zinc alloy).
Plating, nickel plating, tin plating, cobalt plating and the like.

The steel cord wire having a diameter of 0.15 to 1.00 mm is usually used.

The adhesive used for bonding the outer rubber layer 3 and the reinforcing layer 2 includes a group that vulcanizes and reacts with the peroxide vulcanized rubber of the outer rubber layer 3 and a steel cord wire of the reinforcing layer 2. Those having both groups are used.

Examples of the group that undergoes a vulcanization reaction with the peroxide-cured rubber of the outer rubber layer 3 include a vinyl group, an epoxy group, and a methacryl group.

Examples of the group that reacts with the steel cord wire of the reinforcing layer 2 include an ethoxy group, an acetoxy group, and a methoxy group.

Examples of the adhesive having both a group that undergoes a vulcanization reaction with the peroxide-cured rubber and a group that reacts with the steel cord wire include silane-based adhesives.
An example is a chlorinated rubber-phenol resin adhesive. Among these, the use of the above-mentioned silane-based adhesive is preferable because it exhibits stable adhesive performance in a high-temperature atmosphere and after thermal aging, and improves dynamic fatigue durability.

Examples of the silane-based adhesive include those represented by the following general formula (3). In the general formula (3), examples of the group represented by X include an ethoxy group, an acetoxy group, and a methoxy group, and examples of the group represented by Y include a vinyl group, an epoxy group,
A methacryl group and the like, and as a group represented by R,
For example, an alkyl group such as a methyl group and an ethyl group can be mentioned.

[0027]

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Examples of the chlorinated rubber-phenol resin adhesive include chloroprene rubber-resole adhesive.

The heat-resistant high-pressure hose of the present invention can be manufactured, for example, as follows. That is, first,
The peroxide vulcanized rubber, the peroxide, and other components, if necessary, are blended and kneaded using a kneader such as a kneader to prepare an outer rubber layer forming material. Similarly, an inner rubber layer forming material is prepared. Next, the inner rubber layer forming material is extruded onto a mandrel to form the inner rubber layer 1 using an extruder.
Then, a reinforcing layer 2 is formed on the outer peripheral surface of the inner rubber layer 1 by braiding a steel cord wire into a blade shape, a spiral shape, or the like. Subsequently, the special adhesive having the specific group is applied on the reinforcing layer 2 and air-dried. Further, the outer rubber layer forming material is extruded on the surface to which the adhesive is applied by using an extruder to form the outer rubber layer 3. Next, after performing peroxide vulcanization under predetermined conditions, the target heat-resistant high-pressure hose can be manufactured by extracting the mandrel (see FIG. 1).

The method for applying the special adhesive having the specific group is not particularly limited, and examples thereof include a dropping method (shower coating), a dipping method, a spray coating, and a brush coating.

The conditions for the peroxide vulcanization are as follows:
Usually, it is set in the range of 140 to 180 ° C. × 10 to 60 minutes.

The heat-resistant high-pressure hose thus obtained has an inner rubber layer having a thickness of usually 1.0 to 5.0 mm, and an outer rubber layer having a thickness of usually 1.0 to 5.0 mm.
And the thickness of the reinforcing layer per layer is usually 0.15
２．０2.0 mm. The inner diameter of the heat-resistant high-pressure hose is
Usually, it is 5 to 70 mm.

The heat-resistant high-pressure hose of the present invention can be used, for example, as a power steering hose of an automobile, a hydraulic hose of a construction machine, and various hydraulic hoses.

In the present invention, it is also possible to bond the interface between the inner rubber layer and the reinforcing layer using the above-mentioned special adhesive. In this case, the inner rubber layer can be bonded in the same manner as the outer rubber layer. By forming using a peroxide vulcanized rubber, during vulcanization, the adhesive becomes chemically bonded to both the peroxide vulcanized rubber of the inner rubber layer and the steel cord wire of the reinforcing layer, The adhesive strength between the inner rubber layer and the reinforcing layer is improved, and the strength of the entire hose is improved, which is more preferable.

Next, examples will be described together with comparative examples.

[0036]

Example 1 [Preparation of Outer Rubber Layer Forming Material] Chlorinated polyethylene (CPE) [manufactured by Daiso, Daisorak H-
135] with 100 parts of dicumyl peroxide (DP
C) 2.5 parts, SRF carbon black 90 parts, M
A mixture of 5 parts of gO, 45 parts of octyl trimellitate, and 2 parts of TAIC was kneaded using a kneader to prepare an outer rubber layer forming material.

[Preparation of Inner Rubber Layer Forming Material] An inner rubber layer forming material was prepared in the same manner as in the preparation of the outer rubber layer forming material.

[Preparation of Hose] First, the material for forming the inner rubber layer was extruded onto a mandrel using an extruder to form an inner rubber layer. Then, on the outer peripheral surface of the inner rubber layer, a brass-plated steel cord wire (having a diameter of 0.3
2 mm) was braided into a blade to form a reinforcing layer.
Subsequently, on the reinforcing layer, silane-based adhesive agent represented by the formula _{(3) (X: -COCH 3} , Y: -CH = CH
_2, R: After the -CH ₃₎ shower application, and air-dried.
Further, the outer rubber layer forming material was extruded on the surface to which the adhesive was applied using an extruder to form an outer rubber layer. Next, peroxide vulcanization was performed at 160 ° C. for 60 minutes, and then the above mandrel was pulled out to produce a target hose (inner diameter: 9.7 mm). The thickness of the inner rubber layer was 2.1 mm, and the thickness of the outer rubber layer was 1.6.
mm, and the thickness of the reinforcing layer was 0.6 to 0.8 mm.

[0039]

Example 2 Instead of the silane-based adhesive, a rubber chloride was used.
A phenol resin adhesive (chloroprene rubber-resole adhesive) was used. Otherwise, a hose was produced in the same manner as in Example 1.

[0040]

Comparative Example 1 A chlorinated rubber-based adhesive (chloroprene rubber-based adhesive) was used in place of the silane-based adhesive. Otherwise, a hose was produced in the same manner as in Example 1.

[0041]

Comparative Example 2 [Preparation of Outer Rubber Layer Forming Material] 100 parts of chloroprene rubber (manufactured by DuPont Dow Elastomers, Neoprene WK), 1.0 part of sulfur (vulcanizing agent), SR
F carbon black 100 parts, stearic acid 2 parts,
5 parts of ZnO, 4 parts of ozonone 6C, and process oil 1
0 parts and a mixture of 1.0 part of a crosslinking accelerator DT,
The mixture was kneaded using a kneader to prepare an outer rubber layer forming material.

[Preparation of Inner Rubber Layer Forming Material] An inner rubber layer forming material was prepared in the same manner as in the preparation of the outer rubber layer forming material.

[Preparation of Hose] The above-mentioned inner rubber layer forming material and outer rubber layer forming material were used and sulfur vulcanized (1).
A hose was produced in the same manner as in Comparative Example 1 except that the heating was performed at 50 ° C. for 60 minutes.

[0044]

Comparative Example 3 The above formula (3) was used instead of the chlorinated rubber-based adhesive.
A hose was prepared in the same manner as in Comparative Example 2 except that the silane-based adhesive represented by

Using the hoses of Examples and Comparative Examples thus obtained, a peeling test and a heat aging test were performed according to the following criteria. The results are shown in Tables 1 to 3 below.

[Peeling Test] The peeling test was conducted according to JIS K6.
330. That is, the obtained hose was cut so as to have a length of 25 mm, and cut in the longitudinal direction to prepare a test sample. Then, under a predetermined temperature condition, the outer rubber layer was peeled from the cut surface of the test sample, and the peeled end was fixed to a gripping jig of a tensile tester,
A tensile test was performed at a tensile speed of 25 mm / min, the peel strength was determined from the obtained load, and the peel state at that time was visually observed.

[Heat aging test] After heating at a predetermined temperature for 72 hours, the peel strength was measured again by the above-mentioned measuring method, and the peeled state at that time was visually observed.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

From the results shown in Tables 1 to 3, all of the hoses of the examples have a large peeling strength, and the peeling state is not interface peeling but shows outer rubber breakage.
It can be seen that the adhesion between the outer rubber layer and the reinforcing layer is good. In particular, since the hose of Example 1 uses a silane-based adhesive, it can be seen that the adhesiveness in a high-temperature atmosphere and after heat aging is good.

On the other hand, the hose of Comparative Example 1 has a lower peel strength as a whole than the hose of Example, and the peeling state is peeled at the interface between the outer rubber layer and the adhesive portion. This indicates that the adhesion between the outer rubber layer and the reinforcing layer is poor. This is because the chlorinated rubber-based adhesive has only a group that reacts with the steel cord wire of the reinforcing layer and does not have a group that vulcanizes and reacts with the peroxide vulcanized rubber (CPE) of the outer rubber layer. This is considered to be because only the adhesion to the reinforcing layer was good and the adhesion to the outer rubber layer was poor.

In the hose of Comparative Example 2, since the inner rubber layer and the outer rubber layer were formed using sulfur vulcanized rubber, the inner rubber layer and the outer rubber layer were formed using peroxide vulcanized rubber. It can be seen that the adhesiveness of the outer rubber layer and the reinforcing layer after thermal aging is inferior to that of the hose of Example 1 formed.

In the hose of Comparative Example 3, since the inner rubber layer and the outer rubber layer were formed using sulfur vulcanized rubber, the outer rubber layer and the adhesive were chemically bonded as in Comparative Example 1. It can be seen that the adhesiveness is inferior to that of the hose of Example 1 in which the inner rubber layer and the outer rubber layer are formed using a peroxide-cured rubber without performing the above.

[0055]

As described above, in the heat-resistant high-pressure hose of the present invention, at least the outer rubber layer of the inner rubber layer and the outer rubber layer is formed by using a peroxide-cured rubber. The layer and the reinforcing layer are bonded together using an adhesive having both a group that vulcanizes with the rubber of the outer rubber layer and a group that reacts with the steel cord wire of the reinforcing layer. Therefore, at the time of the vulcanization reaction, the adhesive exhibits chemical bonding to both the rubber of the outer rubber layer and the steel cord wire of the reinforcing layer, and the adhesive strength between the outer rubber layer and the reinforcing layer is improved. As a result, no air layer (air layer) is interposed between the outer rubber layer and the reinforcing layer, and the steel cord wire of the reinforcing layer is not oxidized (rusted) by water or heat when the hose is used. This has the effect that the hose function can be maintained for a long time. In addition, in-process defects such as blistering of the outer rubber layer at the end of the hose (caulking portion) and insertion failure of fittings are reduced. Furthermore, by improving the adhesive strength between the outer rubber layer and the reinforcing layer, it is possible to suppress the behavior of the steel cord wire in the reinforcing layer and to suppress the spread of the steel cord wire when polishing the hose end. Can be.

When both the inner rubber layer and the outer rubber layer are formed of peroxide-cured rubber, the inner rubber layer is also chemically bonded to the steel cord wire by the adhesive. And the adhesive strength between the inner rubber layer, the reinforcing layer and the outer rubber layer is improved, and a hose having higher heat resistance can be obtained.

When a silane-based adhesive is used as the adhesive, stable adhesive performance is exhibited in a high-temperature atmosphere and after thermal aging, and the dynamic fatigue durability is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a heat-resistant high-pressure hose of the present invention.

[Explanation of symbols]

 1 inner rubber layer 2 reinforcing layer 3 outer rubber layer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Nobuaki Niki 3-1-1 Higashi 3-chome, Komaki City, Aichi Prefecture F-term (reference) 3H111 AA02 BA13 CB04 CB10 CC08 CC18 DA07 DA11 DB12 EA15 4F100 AA37A AA37C AA37H AB04B AH02A AH02C AH02H AK10A AK10C AK52G AN00A AN00C BA03 BA10A BA10C BA13 CA02A CA02C CB00 DA11 DG01B DG12B GB90 JK06

Claims (3)

[Claims] 1. A heat-resistant high-pressure hose comprising an inner rubber layer, a reinforcing layer formed of a steel cord wire formed on the outer periphery of the inner rubber layer, and an outer rubber layer formed on the outer periphery of the reinforcing layer. Wherein at least the outer rubber layer of the inner rubber layer and the outer rubber layer is formed of peroxide-cured rubber, and the outer rubber layer and the reinforcing layer are combined with the rubber of the outer rubber layer. A heat-resistant and high-pressure hose which is bonded using an adhesive having both a group that reacts with sulfur and a group that reacts with a steel cord wire of a reinforcing layer. 2. The heat-resistant high-pressure hose according to claim 1, wherein each of the inner rubber layer and the outer rubber layer is formed of a peroxide-cured rubber. 3. The heat-resistant high-pressure hose according to claim 1, wherein the adhesive is a silane-based adhesive.