JPH0531457B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a heat-resistant high-pressure hose, and more particularly to a heat-resistant high-pressure hose that is used in hydraulic equipment and the like and has extremely excellent oil resistance and heat resistance. Prior Art Hoses used in automobiles, construction machinery, various hydraulic equipment, etc. are used with heated oil under high temperature and pressure for long periods of time, and deterioration of hoses under such conditions is always a serious problem. If the hose deteriorates significantly, maintenance and replacement require a great deal of time and effort, and can sometimes lead to serious accidents. It has excellent oil resistance and can withstand such high temperatures (120℃~150℃).
Polymers that can withstand continuous use under ℃) environment include chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber (NBR), acrylic rubber (ACM), ethylene-acrylic rubber (AEM),
Ethylene-acrylic-vinyl acetate copolymer rubber (ER), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM), and
Rubbers in which the conjugated diene portion is hydrogenated (so-called hydrogenated NBR), such as acrylonitrile-phtadiene copolymer rubber (NBR), are known. In particular, it is generally known that hydrogenated NBR with a high hydrogenation rate is excellent in both heat resistance and oil resistance, and it is also known that vulcanization with organic peroxides is required when the hydrogenation rate is high. It is. Furthermore, hydrogenated NBR with such a high hydrogenation rate
An organic peroxide vulcanized rubber composition containing as a polymer has poor adhesion to brass-plated pressure-reinforced steel wire, so brass-plated pressure-reinforced steel wire is used as a reinforcing layer for hoses used at high temperatures and high pressures. When used, it may be repeatedly bent or subjected to negative pressure due to insufficient adhesion to the pressure-resistant reinforcing steel wire.
Alternatively, when the oil flow rate is high, interfacial peeling occurs between the oil and the pressure-resistant reinforcing steel wire. Furthermore, when the metal fittings are tightened, interfacial peeling, ie, bulges, occur between the metal fittings and the pressure-resistant reinforcing steel wires, which causes the hose to break. For this reason, the present applicant has disclosed a rubber composition in which an organic sulfur-containing compound is blended into an organic peroxide vulcanized rubber composition of hydrogenated NBR to improve adhesion to brass. Adhesion to the pressure-resistant reinforced steel wire, etc. has been improved (patent application filed on October 31, 1985). However, in this adhesive rubber composition, the crosslinking efficiency decreases due to the mutual reaction between the organic sulfur-containing compound and the organic peroxide, and the stress (for example, 100% Due to the low Mosieras), hoses used under high pressure have disadvantages such as oil leakage from the fitting tightening part due to internal stress. Therefore, neither the rubber composition nor the adhesive rubber composition can be used for the inner layer of a hose (so-called high-pressure hose) having the pressure-resistant reinforcing steel wire as a reinforcing layer, and it is difficult to develop a hose that takes advantage of the advantages of the rubber composition. could not be manufactured. OBJECTS OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks of the prior art and to provide a heat-resistant high-pressure hose that can withstand long-term use with heated oil in a high-temperature environment. DETAILED DESCRIPTION OF THE INVENTION The present invention provides a high-pressure hose having at least an inner layer, an adhesive rubber layer, and a pressure-resistant reinforcing steel wire layer plated with brass, in which a unit portion of unsaturated nitrile is added in the polymer chain by 10 to 45 weight units. %, unit parts from conjugated dienes from 0 to 20% by weight, unit parts from ethylenically unsaturated monomers other than unsaturated nitriles, and/or
Or a rubber composition prepared by blending 1 to 15 parts by weight of an organic peroxide vulcanizing agent to 10 parts by weight of a copolymer rubber having 90 to 35% by weight of a unit part obtained by hydrogenating a unit part from a conjugated diene. The inner layer is made of the substance (A), and on top of this inner layer, the adhesive rubber is formed by a rubber composition (B) obtained by blending the rubber composition (A) with 0.1 to 15 parts by weight of an organic sulfur-containing compound. A pressure-resistant reinforcing steel wire layer plated with brass is placed on top of the adhesive rubber layer to cover it, and by heating and crosslinking, the inner layer is reinforced with the pressure-resistant material through the adhesive rubber layer. The present invention provides a heat-resistant high-pressure hose that is firmly bonded to a steel wire layer. Here, the organic sulfur-containing compound has the general formula: 6-R-2,4-dimercapto-1,3,5-triazine, (wherein R is a mercapto group, an alkoxy group, a mono- or di-alkylamino group, or di-cycloalkylamino group, mono- or di-
It is a group selected from the group consisting of an arylamino group and an N-alkyl-N'-arylamino group. ) It is preferable that it is a compound shown by these. The present inventors have demonstrated excellent oil resistance and a temperature of 120℃ to 150℃.
In order to manufacture high-pressure hoses that can be used continuously for long periods of time, various research efforts have been conducted on copolymer rubbers in which the conjugated diene portion of acrylonitrile-butadiene copolymer rubber is hydrogenated (so-called hydrogen Hydrogenated NBR), especially hydrogenated NBR with a high hydrogenation rate
Focusing on its excellent heat resistance and oil resistance,
I did further research. Hydrogenated NBR with a high hydrogenation rate requires vulcanization with organic peroxide, and a rubber composition containing hydrogenated NBR and an organic peroxide vulcanizing agent can be used with brass-plated pressure-reinforced steel wire. It is generally known that there is no adhesion. Therefore, a high-pressure hose using the rubber composition could not be put to practical use. For this reason, the applicant proposed an adhesive rubber composition in which an organic sulfur-containing compound is blended with the organic peroxide vulcanized rubber composition, thereby improving the adhesion with the pressure-reinforced steel wire. (Patent application filed on October 31, 1960). However, this adhesive rubber composition has lower stress (for example, 100% modulus) than rubber compositions that do not contain organic sulfur-containing compounds, so when used in hoses used under high pressure, There were problems such as oil leaking from the fittings' tightening parts due to pressure. The present inventors have discovered that a rubber composition (A) that does not contain an organic sulfur-containing compound and a rubber composition (B) that contains an organic sulfur-containing compound have adhesive properties.
Pressure-resistant reinforcing steel wire plated with brass and rubber composition
They discovered that bonding occurs through (B), leading to the present invention. The present invention will be explained in detail below. The present invention provides a rubber composition in which the rubber composition (A) is used as an inner layer.
(B) is placed on top of it to form an adhesive rubber layer, and then a brass-plated pressure-reinforced steel wire is placed on top of that, and an outer layer is placed on top of that as necessary, and then the pressure-resistant reinforced steel wire is placed as necessary. A strong initial adhesive force between the rubber composition (A) and the brass-plated pressure-reinforced steel wire is achieved by repeatedly applying layers corresponding to the outer layer and the outer layer, and then vulcanizing and integrating the layers. A heat-resistant high-pressure hose is produced by utilizing the heat resistance of the rubber composition (A). (1) Rubber composition (A) The following copolymer rubber called hydrogenated NBR is used as the rubber composition (A) to form the inner layer of the hose of the present invention, which has excellent heat resistance and oil resistance. In other words, hydrogenated NBR contains 10 to 45% by weight of units from unsaturated nitriles, 0 to 20% by weight of units from conjugated dienes, and ethylenically unsaturated units other than unsaturated nitriles in the polymer chain. It is a copolymer rubber having 90 to 35% by weight of hydrogenated unit parts from polymers and/or conjugated dienes, and has a saturated ethylene chain (C-C) represented by the following formula, a nitrile group. It is a copolymer rubber composed of a carbon-carbon double bond part (VCN) and a carbon-carbon double bond part (C=C). Here it is written as a nitrile group moiety (VCN)

[Formula] is a unit portion from an unsaturated nitrile and is 10 to 45% by weight. If it is less than 10% by weight, oil resistance will be poor and 45
If it exceeds % by weight, cold resistance will deteriorate. (-
_CH2 - _CH2- )x is a unit moiety derived from an ethylenically unsaturated monomer other than unsaturated nitrile and/or
Alternatively, it is a unit portion obtained by hydrogenating a unit portion from a conjugated diene, and is 90 to 35% by weight. In particular, the hydrogenation rate is preferably 95% or more. If the saturated methylene chain (C-C) is more than 90% by weight, the unit moiety from unsaturated nitrile (VCN)
is relatively reduced, and the oil resistance is poor, making it unusable. In addition, if the saturated methylene chain (C-C) is less than 35% by weight and the unit portion (VCN) from unsaturated nitrile is large, cold resistance is poor, and the saturated methylene chain (C-C) is less than 35% by weight. If the unit portion (VCN) from unsaturated nitrile is small and the C═C portion (described later) is large, the resistance to deteriorated oil will deteriorate. (-CH2 _- CH=CH- _CH2- ) ₂ , denoted by the carbon-carbon double bond moiety (C=C), is a unit moiety from a conjugated diene, with a weight percentage of 0 to 20% by weight. be. This is because if it is outside this range, the resistance to deteriorated oil will be poor. Specific examples of such copolymer rubbers include butadiene-acrylonitrile copolymer rubber, isoprene-acrylonitrile copolymer rubber, hydrogenated butadiene-isoprene-acrylonitrile copolymer rubber, etc.: butadiene-methyl acrylate-acrylonitrile copolymer rubber , butadiene-acrylic acid-acrylonitrile copolymer rubber, etc., and their hydrogenated products: butadiene-ethylene-acrylonitrile copolymer rubber, butyl acrylate-ethoxyethyl acrylate-vinyl chloroacetate-acrylonitrile copolymer rubber, butyl acrylate-ethoxyethyl acrylate Examples include -vinylnorporene-acrylonitrile copolymer rubber and hydrogenated products thereof. These copolymer rubbers may be used alone or in combination of two or more, and in some cases in combination with other rubbers within the scope of the invention. Rubber composition (A) is a rubber composition with excellent heat resistance, which is prepared by blending 1 to 15 parts by weight of the above organic peroxide vulcanizing agent with 100 parts by weight of the copolymer rubber. Organic peroxides as vulcanizing agents are used in rubber compositions
In (A), any organic peroxide may be used as long as the crosslinking reaction does not proceed extremely at the processing temperature.
Preferably, dialkyl peroxide has a half-life of 10 hours and a decomposition temperature of 80°C or higher. For example, dicumyl peroxide, 1,3-
Bis-(t-butyl-peroxo-isopropyl)benzene and 4,4-di-tertiary-butylperoxyvaleric acid n-butyl are mentioned. If the amount of the organic peroxide vulcanizing agent is less than 1 part by weight, it will be difficult to develop the physical properties, and if it is more than 15 parts by weight, the organic peroxide residue will affect heat aging, which is undesirable. Rubber composition (A) is prepared by mixing and kneading commonly used fillers, reinforcing agents, plasticizers, anti-aging agents, and other compounding agents as necessary. (2) Rubber composition (B) Rubber composition (B) as an adhesive rubber layer is a rubber composition (A) containing 6-R-2,4-dimercapto-1,3,5-
For 100 parts by weight of copolymer rubber using an organic sulfur-containing compound such as triazine in the rubber composition (A),
The rubber composition contains 0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, and other necessary compounding agents. Here, 6-R-2,4-dimercapto-
1,3,5-triazine is a group of compounds represented by general formula (1). In the above formula, R is a mercapto group, an alkoxy group, a mono- or di-alkylamino group, a mono- or di-cycloalkylamino group, a mono- or di-arylamino group, or an N-alkyl-N'-
It is a group selected from the group consisting of arylamino groups. In particular, 2,4,6-trimercapto-1,
3,5-triazine is preferred. As the organic sulfur-containing compound, in addition to those mentioned above, commonly used sulfur donors can be used. A sulfur donor is a compound containing sulfur that separates and releases this sulfur as active sulfur during the vulcanization reaction.
It is a substance that acts as a vulcanizing agent, and specifically, it is represented by the formula (R ₂ N・CS) ₂ S ₂ (wherein, R represents a methyl group, ethyl group, pentamethylene group, or hydrogen atom). tetramethylthiuram disulfide, tetraethylthiuram disulfide,
Thiuram disulfide such as tetrapentamethylenethiuram disulfide Formula (R ₂ N.CS) ₂ S ₄ (Formula R represents one or more of a methyl group, an ethyl group, a pentamethylene group, or a hydrogen atom. ), thiuram tetrasulfide such as dipentamethylenethiuram tetrasulfide, 4-4 dithiomorpholine, dimorpholine disulfide, 2-(4-morpholinodithio)
Examples include morpholin derivatives such as benzithiazole. This is because if the amount of the organic sulfur-containing compound is less than 0.1 parts by weight, the adhesive strength will be extremely low, and if it exceeds 15 parts by weight, no effect of improving the adhesive strength can be expected. The above rubber composition (A) is used as an inner layer, and the rubber composition
When (B) is used as an adhesive rubber layer and a pressure-resistant reinforcing steel wire layer plated with brass is placed on top of it, a rubber composition is formed.
It is thought that the reason why the adhesive force between (A) and brass can be imparted is that the organic sulfur-containing compound contributes to both the direct reaction with the copper component in the brass and the crosslinking reaction to the rubber. As shown in FIG. 1, the heat-resistant high-pressure hose of the present invention has a structure including at least an inner layer 1 made of the rubber composition (A), an adhesive rubber layer 2 made of the rubber composition (B) thereon, and an inner layer 1 made of the rubber composition (A). On top of this, a pressure-resistant reinforcing steel wire layer 3 plated with brass so as to cover this
If necessary, an outer layer 4 may be applied thereon, and layers corresponding to the pressure-resistant reinforcing steel wire layer and the outer layer may be repeatedly applied on the outer layer, if necessary. In this case, the layer corresponding to the outer layer sandwiched between the two pressure-resistant reinforcing steel wire layers is hereinafter referred to as an intermediate rubber layer.
Moreover, the thickness of the adhesive rubber layer B and the intermediate rubber layer is preferably 0.05 to 0.5 mm, more preferably 0.1 to 0.3 mm. If the thickness of the adhesive rubber layer and the intermediate rubber layer is less than 0.05 mm, the adhesive stability will be poor due to flow during the vulcanization process, and if the thickness exceeds 0.5 mm, the adhesive will deteriorate during use under high pressure. The rubber layer and/or the intermediate rubber layer may be destroyed and cannot be put to practical use. Further, although the intermediate rubber is a thin rubber layer sandwiched between the pressure-resistant reinforcing steel wire layers, it has the purpose of firmly adhering the pressure-resistant reinforcing steel wires. The rubber used for the outer layer may be any material as long as it adheres to the pressure-resistant reinforcing steel wire of the outermost layer and has properties such as oil resistance, and the same composition as the adhesive rubber layer of the present invention may be used for the intermediate rubber layer and the outer layer. Styrene-butadiene copolymer rubber (SBR), chloroprene rubber (CR), and acrylonitrile-butadiene copolymer rubber (NBR), which have traditionally been used for high-pressure hoses.
A compounded rubber having good adhesion to the pressure-resistant reinforcing steel wire may be used. In addition, the pressure-resistant reinforcing steel wire used is brass-plated, and the appropriate wire diameter is selected depending on the amount of pressure applied to the high-pressure hose, and the wire is wrapped in a braided structure or spirally in alternating left and right directions. A so-called spiral reinforcement structure is adopted. The heat-resistant high-pressure hose with the above-mentioned structure is molded on a mandrel, covered with a lead pipe by wrapping or using a lead coating machine, and then placed in a vulcanizing can and immersed in steam at 130°C to 200°C for a certain period of time. The rubber composition of each layer such as the inner layer and the outer layer is crosslinked by holding the rubber composition. In this heating crosslinking process, the rubber composition of each layer becomes rubber-like elastic, and the rubber composition of each layer and the brass-plated pressure-reinforced steel wire layer are strengthened by a chemical reaction at the interface between them. Glued. In this way, the rubber composition (A) is used for the inner layer of the high-pressure hose, and the rubber composition is used for the adhesive rubber layer.
By using (B), a high-pressure hose can be obtained that has good adhesion to the brass-plated pressure-resistant reinforcing steel wire layer and has a high degree of oil resistance and heat resistance. Examples The present invention will be specifically described below using Examples and Comparative Examples.

【table】

【table】

[Description of raw materials used]

(1) SRF Asahi Carbon Asahi #50 (2) VulkanoxDDA Bayer (3) Vulkanox ZMB-2 Bayer (4) WAX HoechstAG PE200 (5) TAIC Nippon Kasei Triallylisocyanate (6) Witamol218 Dynamite Nobel
Trimellitic acid ester (7) Parkadox 14/40 Kayaku Nouri (8) ZISNET F Sankyo Kasei The rubber compositions of compounding agents 1 to 3 shown in Tables 1 and 2 were mixed in a Banbury mixer, and the mixture was prepared as described below. A hose was manufactured and subjected to a heat aging test. Example 1 1 The rubber composition (A) of Formulation Example 1 having a thickness of 1.5 mm was extruded onto a mandrel having an outer diameter of 12.7 mm. 2 Apply 0.5 mm of the rubber composition (B) of Compounding Example 2 to the outer periphery.
It was wrapped in a thick rubber sheet. 3 Next, a brass-plated pressure-resistant reinforcing steel wire was applied onto the compound-coated surface using a braiding machine. 4 Furthermore, using an extruder, a CR-based rubber composition generally used for high-pressure hoses was coated on this pressure-resistant reinforcing steel wire layer to a thickness of 1.2 mm. 5 Next, a lead pipe was coated on top of this coating compound using a lead coating machine and vulcanized at 160° C. for 90 minutes in a steam vulcanizer. 6 After vulcanization, the surface-coated lead pipe and mandrel were removed to obtain a high-pressure hose having the structure of the present invention. Fittings (not shown) were attached to both ends of this hose, the inside of the hose was filled with hydraulic oil, and the hose was aged at 150°C for 168 hours. This did not occur, and the flexibility of the hose did not decrease. Furthermore, even when a pressure test (pressurized at 600 kgf/cm ² ) was conducted, no oil leaked. Example 2 1 The rubber composition (A) of Formulation Example 1 having a thickness of 1.5 mm was extruded onto a mandrel having an outer diameter of 12.7 mm. 2 Apply 0.5 mm of the rubber composition (B) of Blend Example 3 on the outer periphery.
Wrapped as a thick rubber sheet. 3 Next, a brass-plated pressure-resistant reinforcing steel wire was applied onto the compound-coated surface using a braiding machine. 4 Further, on this pressure-resistant reinforcing steel wire layer, a CR-based rubber composition similar to that used in Example 1 was coated with a thickness of 1.2 mm using an extruder. 5 Next, a lead pipe was coated on top of this coating compound using a lead coating machine and vulcanized at 160° C. for 90 minutes in a steam vulcanizer. 6 The vulcanized surface-coated lead pipe and mandrel were removed to obtain a high-pressure hose having the structure of the present invention. This hose was heated to 150°C in the same manner as in Example 1.
Although the hose was heated and aged for 168 hours, no bulges occurred due to peeling at the fastening parts of the fittings, and there was no decrease in the flexibility of the hose. Furthermore, even when a pressure test (pressurized at 600 kgf/cm ² ) was conducted, no oil leaked. Comparative Example 1 1 The rubber composition (A) of Formulation Example 1 having a thickness of 1.5 mm was extruded onto a mandrel having an outer diameter of 12.7 mm. 2 Next, a pressure-resistant reinforcing steel wire plated with brass was applied onto the compound-coated surface using a braiding machine. 3 Furthermore, using an extruder, the same CR-based rubber composition as in the example was applied on top of this pressure-resistant reinforcing steel wire layer.
It was coated with a thickness of 1.2mm. 4 Next, a lead pipe was coated on top of this coating mixture using a lead coating machine and vulcanized at 160°C for 90 minutes in a steam vulcanizer. 5 After vulcanization, the surface-coated lead pipe and mandrel were removed to obtain a high-pressure hose of 1.5 mm thick inner tube rubber/pressure-resistant reinforcing steel wire layer/1.2 mm thick outer tube rubber. As described in Examples 1 and 2, this hose was fitted with fittings (not shown) at both ends, filled with hydraulic oil, and heated and aged at 150°C for 24 hours. The adhesion between the hose and the hose was poor, and a bulge occurred at the tightening part of the metal fitting, and the hose did not perform well as a high-pressure hose. Comparative Example 2 1 The rubber composition (B) of Formulation Example 2 with a thickness of 1.5 mm was extruded onto a mandrel with an outer diameter of 12.7 mm. 2 Next, a pressure-resistant reinforcing steel wire plated with brass was applied onto the compound-coated surface using a braiding machine. 3 Furthermore, using an extruder, the same CR-based rubber composition as in the example was applied on top of this pressure-resistant reinforcing steel wire layer.
It was coated with a thickness of 1.2mm. 4 Next, a lead pipe was coated on top of this coating mixture using a lead coating machine and vulcanized at 160°C for 90 minutes in a steam vulcanizer. 5 After vulcanization, the surface-coated lead pipe and mandrel were removed to obtain a high-pressure hose of 1.5 mm thick inner tube rubber/pressure-resistant reinforcing steel wire layer/1.2 mm thick outer tube rubber. When fittings (not shown) were attached to both ends of this hose and a pressure test (pressurized at 600Kgf/ ^cm2 ) was conducted, oil leaked from the fittings' tightening parts and the hose did not perform well as a high-pressure hose. . Comparative Example 3 1 The rubber composition (B) of Formulation Example 3 having a thickness of 1.5 mm was extruded onto a mandrel having an outer diameter of 12.7 mm. 2 Next, a pressure-resistant reinforcing steel wire plated with brass was applied onto the compound-coated surface using a braiding machine. 3 Furthermore, using an extruder, the same CR-based rubber composition as in the example was applied on top of this pressure-resistant reinforcing steel wire layer.
It was coated with a thickness of 1.2mm. 4 Next, a lead pipe was coated on top of this coating mixture using a lead coating machine and vulcanized at 160°C for 90 minutes in a steam vulcanizer. 5 After vulcanization, the surface-coated lead pipe and mandrel were removed to obtain a high-pressure hose of 1.5 mm thick inner tube rubber/pressure-resistant reinforcing steel wire layer/1.2 mm thick outer tube rubber. When this hose was subjected to a pressure test (pressurized at 600 Kgf/cm ² ) in the same manner as in Comparative Example 2, oil leaked from the fastening part of the metal fittings, and the hose did not exhibit its performance as a high-pressure hose. Effects of the invention The heat-resistant high-pressure hose of the present invention can be used at high temperatures (from 120°C to
150℃) and high pressure (600Kgf/cm ² ) for long periods of time, there is no bulge due to peeling at the tightening part of the fittings, the flexibility of the hose does not decrease, and there is no oil leakage in the pressure test. This is a high-pressure hose with extremely excellent heat resistance, which has never been seen before.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the heat-resistant high-pressure hose of the present invention. Explanation of symbols, 1... Inner layer, 2... Adhesive rubber layer,
3...Pressure-resistant reinforced steel wire layer, 4...Outer layer.

Claims (1)

[Claims] 1. A high-pressure hose having at least an inner layer, an adhesive rubber layer and a pressure-resistant reinforcing steel wire layer plated with brass, in which a unit portion from unsaturated nitrile is contained in the polymer chain in an amount of 10 to 45% by weight as the inner layer. and 0 to 20% by weight of a unit part from a conjugated diene, and a unit part 90 to 35 hydrogenated from an ethylenically unsaturated monomer other than an unsaturated nitrile and/or a unit part from a conjugated diene. copolymer rubber with wt%
Using a rubber composition (A) containing 1 to 15 parts by weight of an organic peroxide vulcanizing agent per 100 parts by weight, the rubber composition (A) is coated as an adhesive rubber layer on top of this inner layer. A rubber composition (B) containing 0.1 to 15 parts by weight of an organic sulfur-containing compound is used, and a pressure-resistant reinforcing steel wire layer plated with brass is applied to cover the adhesive rubber layer, followed by heating. A heat-resistant high-pressure hose, characterized in that the inner layer is firmly adhered to the pressure-resistant reinforcing steel wire layer through the adhesive rubber layer by crosslinking. 2 The organic sulfur-containing compound has the general formula: 6-R-2,4-dimercapto-1,3,5-triazine, (wherein R is a mercapto group, an alkoxy group, a mono- or di-alkylamino group, a mono- or di-alkylamino group) -cycloalkylamino group, mono or di-
It is a group selected from the group consisting of an arylamino group and an N-alkyl-N'-arylamino group. ) The heat-resistant high-pressure hose according to claim 1, which is a compound represented by: