JPS6361553B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-pressure hose, and more particularly to a high-pressure hose that is used in hydraulic equipment and the like and has excellent properties such as oil resistance and heat resistance.

[Conventional technology and its problems]

High pressure hoses are used in a wide range of fields such as construction vehicles, machine tools, automobiles, and the steel industry.
Recently, efforts have been made to increase the pressure of hydraulic oil and to make hydraulic circuits more compact.As a result, the temperature of the hydraulic oil used in hydraulic equipment increases, so high-pressure hoses are required to have not only pressure resistance and oil resistance, but also heat resistance. It has become like that.

Conventionally, in this type of hose, a rubber based on nitrile rubber (NBR) or chloroprene rubber (CR), which are oil-resistant synthetic rubbers, has been used as the inner tube rubber that comes into contact with internal fluid such as hydraulic oil. These rubbers adhere well to plated pressure-reinforced steel wires without any special adhesive treatment, and will not peel off even when repeatedly bent, under negative pressure, or at high oil flow rates. Also, when the fittings are tightened, the inner tube rubber and the pressure-resistant reinforcing steel wire will not separate, that is, bulges will not occur, but if the hose is continuously used at oil temperatures of 120 to 150 degrees Celsius and subjected to severe repeated bending. After several hundred hours, the inner tube rubber deteriorated due to heat, causing cracks on the inner surface of the hose, or the tightening pressure of the fittings attached to both ends of the hose decreased, resulting in oil leakage.

On the other hand, ethylene-based saturated polymers such as chlorinated polyethylene (CM) and chlorosulfonated polyethylene (CSM) are known to have better heat resistance than highly saturated polymers such as NBR and CR; Ethylene-based saturated polymers have poor adhesion to pressure-resistant reinforcing steel wires, so they cannot fulfill the function of inner tube rubber for high-pressure hoses.

In this way, high pressure hoses that are used continuously at high temperatures
If rubber based on NBR or CR is used, the rubber will deteriorate and its lifespan will be limited, and if ethylene-based saturated polymers such as CM or CSM are used as the inner tube rubber material for high-pressure hoses, they will generally be heat-resistant. However, in order to obtain high rubber elasticity, good compression set, and further heat resistance, which are essentially important properties for the inner tube rubber material of high-pressure hoses,
Among various types of crosslinking, organic peroxide crosslinking is considered necessary or preferable. However, when attempting to apply organic peroxide crosslinking to polymer compositions based on these ethylene-based saturated polymers,
It could not be used as a high-pressure hose because it did not adhere well to conventional pressure-resistant reinforcing steel wire.

(Object of the Invention) The present invention was made in order to eliminate such drawbacks, and an object of the present invention is to provide a high-pressure hose that is excellent in heat resistance, oil resistance, and pressure resistance.

[Background of the invention]

The inventors have discovered that chlorinated polyethylene (CM),
A polymer composition in which an organic peroxide, an epoxy resin, and a trimercaptotriazine are added to an ethylene-based saturated polymer that is effective in crosslinking with an organic peroxide such as chlorosulfonated polyethylene (CSM),
When used as the adhesive rubber layer (layer between the inner tube rubber and pressure-resistant reinforced steel wire) of a high-pressure hose that uses the inner tube rubber of a high-pressure hose or the ethylene-based saturated polymer as an inner tube, brass-plated pressure-resistant reinforced steel wire The present inventors have discovered that this polymer composition has good adhesion to high-pressure hoses, and also has excellent physical properties necessary for high-pressure hoses, such as heat resistance and oil resistance.

[Means for solving problems]

The heat-resistant high-pressure hose of the present invention is composed of (1) inner tube rubber (inner layer), brass-plated pressure-resistant reinforcing steel wire layer (middle layer), and outer tube rubber (outer layer), or (2) inner tube rubber ( Inner layer), adhesive rubber layer, brass-plated pressure-resistant reinforcing steel wire layer (center layer), and outer tube rubber (outer layer); A reinforcing steel wire layer (hereinafter simply referred to as a pressure-resistant reinforcing steel wire layer in some cases) and a layer corresponding to the outer tube rubber may be further repeatedly stacked as necessary. In this case, the layer corresponding to the outer tube rubber sandwiched between the two pressure-resistant reinforcing steel wire layers is hereinafter referred to as intermediate rubber, and the adhesive rubber layer and the intermediate rubber have a thickness of 0.3 to 0.5 mm as a pressure-resistant hose. preferable.

The polymer composition used for the inner tube rubber (1) and the adhesive rubber layer (2) in the present invention includes an ethylene-based saturated polymer, an organic peroxide, an epoxy resin, and a trimercaptotriazine represented by the following formula. It is characterized by consisting of.

The ethylene-based saturated polymer with excellent heat resistance and effective organic peroxide crosslinking that can be used in the polymer composition may be any polymer having such properties, such as chlorinated polyethylene (CM), chlorosulfonated polyethylene, etc. Polyethylene (CSM), epichlorohydrin rubber (CHC,
CHR), and preferably CM, CSM, etc., in which organic peroxide crosslinking can provide a better crosslinking density than crosslinking systems such as sulfur or metal oxides.

Any type of organic peroxide may be used as long as the crosslinking reaction does not proceed to an extreme extent at the temperature during processing in the formulation system of the polymer composition, and preferably the half-reduced group is at the decomposition temperature or 80°C in 10 hours.
The above dialkyl peroxides are preferable. Examples include dicumyl peroxide, n-butyl 4,4'-di-tertiarybutylperoxyvalericate, and 1,3-bis-(t-butyl-peroxy-isopropyl)benzene, among which 4, Most preferred is n-butyl 4'-di-t-butylperoxyvalericate.

In addition, the type of epoxy compound may be any mono- or di- or more-functional epoxide as long as it is an epoxy resin that can react with trimercaptotriazine, and the resin structure may be glycidyl ether type, glycidyl ester type, or glycidyl amine type. , linear aliphatic epoxide, or alicyclic epoxide.

In order for the polymer composition to maintain good adhesion to the brass-plated steel wire, which is the pressure-resistant reinforcing steel wire layer, as the inner tube rubber or adhesive rubber layer of the heat-resistant high-pressure hose, the ratio of each component in the polymer composition is as follows: , 1 to 30 parts by weight, preferably 2 to 20 parts by weight (1
If less than 30 parts by weight, it will not crosslink, and if it exceeds 30 parts by weight, it will cause scorch, making it impractical. as the amount of trimercaptotriazine in a ratio of 5
It is added in an amount of 0.001 to 0.1 mol (0.177 to 17.7 parts by weight), preferably 0.007 to 0.07 mol (1.2 to 12 parts by weight). If trimercaptotriazine is less than 0.001 mol, it will not adhere, and if it exceeds 0.1 mol, it will react with the organic peroxide and inhibit crosslinking. If there are less than 0.1 epoxy groups per mole of trimercaptotriazine, the adhesive effect due to the synergistic action with trimercaptotriazine will not appear, and if there are more than 10 epoxy groups, the epoxy groups will react with trimercaptotriazine, resulting in no adhesion.

In addition, in order to impart processability to the inner tube rubber or the adhesive rubber layer, the polymer composition may contain, if necessary,
Of course, plasticizers, reinforcing agents, pigments, etc. can be added.

As the inner tube rubber (2) in the present invention, there is used a blended composition of ethylene-based saturated polymers based on CM, CSM, etc., which have excellent pressure resistance and oil resistance, and are effectively crosslinked with organic peroxides.

In addition, the pressure-resistant reinforcing steel wire 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 braided or spirally wound in alternating left and right directions. structure is adopted.

Furthermore, the intermediate rubber is a thin rubber layer sandwiched between layers of pressure-resistant reinforcing steel wire, and has the purpose of firmly adhering the pressure-resistant reinforcing steel wire, and the outer tube rubber also adheres to the outermost layer of pressure-resistant reinforcing steel wire, and is also oil-resistant. Both the intermediate rubber and the outer tube rubber may have the same composition as the inner tube rubber in (1) or the adhesive rubber layer in (2) in the present invention, or they may be used under higher pressure than before. Compound rubbers such as NBR, CR, or SBR, which have been used for hoses, and which have good adhesion to pressure-resistant reinforcing steel wires by adding sulfur or a sulfur donor may be used.

The heat-resistant high-pressure hose constructed as described above is
Molded on a mandrel (iron core, etc., not shown),
After covering the lead pipe with wrapping or lead-covering machine, it is placed in a heating can and kept in steam at 140 to 160℃ for a certain period of time to thermally crosslink the polymer composition of each layer such as inner tube rubber and outer tube rubber. Let's do it. In this heat crosslinking process, the polymer composition of each layer becomes rubber-like elastic, and the polymer composition of each layer and the brass-plated pressure-reinforced steel wire layer are firmly bonded by a chemical reaction at the interface. Ru. Here, the adhesion reaction between the polymer composition used for the inner tube rubber in (1) or the adhesive rubber layer in (2) and the brass-plated pressure-resistant reinforcing steel wire is caused by the trimercaptate in the polymer composition. A primary bonding reaction between triazine and copper in the brass alloy, a reaction between trimercaptotriazine and an epoxy compound, a crosslinking reaction of rubber with an organic peroxide, and a crosslinking reaction of rubber with trimercaptotriazine proceed in concert, Combined with the secondary bonding force between the epoxy compound and the metal, the organic peroxide crosslinked product exhibits strong adhesion to the brass-plated pressure-reinforced steel wire without deteriorating its physical properties.

In this way, by using the polymer composition for the inner tube rubber or adhesive rubber layer of a high-pressure hose, a high-pressure hose that has good adhesion to the brass-plated pressure-resistant reinforcing steel wire and has a high degree of heat resistance and oil resistance. is obtained.

〔Example〕

The present invention will be explained below using Examples and Comparative Examples.

Example 1 Chlorinated polyethylene with a thickness of 1.5 mm (Erasurene 301A manufactured by Showa Yuka Co., Ltd.) on a mandrel with an outer diameter of 12.7 mm
100 parts by weight, reinforcing material (SRF carbon black) 70
parts by weight, DAP (diallyl phthalate) 10 parts by weight,
DOP (2-ethylhexyl phthalate) 15 parts by weight, TAIC (triaryl isocyanurate) 2
parts by weight, 10 parts by weight of magnesium oxide, 5 parts by weight of epoxy resin (Epicote 828 manufactured by Ciel Chemical Co., Ltd.),
2.22 parts by weight of 1,3,5-trimercaptotriazine (ZISNET F, manufactured by Sankyo Kasei Co., Ltd.), 10 parts by weight of organic peroxide (4,4'-di-t-butyl peroxyvaleric acid n-butyl ester) A polymer composition consisting of parts is extruded. Next, a pressure-resistant reinforcing steel wire plated with brass was applied to the surface coated with the polymer composition using a braiding machine. Furthermore, using an extruder, this pressure-resistant reinforcing steel wire was coated with a CR base compound commonly used for high-pressure hoses to a thickness of 1.2 mm.

Next, a lead pipe was coated on top of the coating mixture using a lead coating machine, and cross-linked by heating at 160°C for 30 minutes in a steam heating can. After crosslinking, the surface-coated lead pipe and mandrel were removed to obtain a high-pressure hose constructed according to 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 heated and aged at 120°C for 96 hours, but no bulges occurred due to peeling at the tightened parts of the hose. Also, the flexibility of the hose did not decrease. Furthermore, when the NBR hose was aged under heat under the same conditions, the flexibility of the hose significantly decreased. Furthermore, even when we conducted a pressure test (pressurized at 600 kg/cm ² ), there was no oil leakage, and we were able to obtain better results compared to conventional NBR hoses.

Example 2 On a mandrel with an outer diameter of 12.7 mm, 100 parts by weight of chlorinated polyethylene (ELASLEN 301A, manufactured by Showa Yuka Co., Ltd.), 70 parts by weight of reinforcing material (SRF carbon black),
DAP (diallyl phthalate) 10 parts by weight, DOP (2 parts by weight)
-Ethylhexyl phthalate) 15 parts by weight, TAIC
(trialyl isocyanunate) 2 parts by weight, magnesium oxide 10 parts by weight, organic peroxide (4,4'-
A formulation consisting of 10 parts by weight of di-t-butylperoxyvaleric acid n-butyl ester)
Extruded at 1.5 m/m, and on the outer periphery 100 parts by weight of chlorinated polyethylene (same as above), 70 parts by weight of reinforcing material (SRF carbon black), 10 parts by weight of DAP (diaryl phthalate), and 15 parts by weight of DOP (2-ethylhexyl phthalate). Parts by weight, 2 parts by weight of TAIC (triaryl isocyanurate), 10 parts by weight of magnesium oxide, 5 parts by weight of epoxy resin (Epicote 828 manufactured by Ciel Chemical Co., Ltd.), 1,3,5-trimercaptotriazine (ZISNET F, Sankyo Kasei) Co., Ltd.) and 10 parts by weight of organic peroxide (4,4'-di-t-butylperoxyvaleric acid n-butyl ester), wrapped as a 0.5 mm thick rubber sheet. Wearing. Next, the polymer composition was applied onto the coated surface using a braiding machine of pressure-resistant reinforcing steel wire plated with brass. Furthermore, using an extruder, a CR base compound commonly used for high-pressure hoses was coated onto this pressure-resistant reinforcing steel wire layer to a thickness of 1.2 mm. Next, the coating mixture was heated and crosslinked at 160° C. for 30 minutes in a steam heating can in which a lead pipe was coated using a lead coating machine.
After crosslinking, the surface-coated lead pipe and mandrel were removed to obtain a high-pressure hose constructed according to the present invention.

This high-pressure hose was
Although the hose was heat-aged at ℃ for 96 hours, local swelling of the tube rubber due to peeling at the tightening part of the metal fittings, so-called bulges, did not occur, and the flexibility of the hose did not decrease. Furthermore, even when a pressure test (pressurized at 600 kg/cm ² ) was performed, there was no oil leakage, and as in Example 1, good results were obtained compared to the conventional NBR hose.

Comparative Example 1 100 parts by weight of chlorinated polyethylene (Elasturene 301A manufactured by Showa Yuka Co., Ltd.), 70 parts by weight of reinforcing material (SRF carbon black), DAP (diallyl phthalate)
10 parts by weight, DOP (2-ethylhexyl phthalate) 15 parts by weight, TAIC (triallylisocyanurate) 2 parts by weight, magnesium oxide 10 parts by weight, organic peroxide (4,4'-di-t-butylperoxyvaleryl) A blend consisting of 10 parts by weight of tsuccinic acid n-butyl ester) was coated on a 12.7 mmφ mandrel using an extruder. The coating thickness of the formulation was 1.5 mm. Next, a pressure-resistant reinforcing steel wire plated with brass was applied onto the compound-coated surface using a braiding machine. Furthermore, the above compound is applied onto this pressure-resistant reinforcing steel wire layer using an extruder.
It was coated with a thickness of 1.2 mm. Next, a lead pipe was coated on top of this coating compound using a lead coating machine, and cross-linked by heating at 160°C for 30 minutes in a steam heating can. After crosslinking, the surface-coated lead pipe and mandrel were removed to obtain a high-pressure hose with a 1.5 mm thick inner tube rubber/pressure-resistant reinforcing steel wire layer/1.2 mm outer tube rubber.

As described in Examples 1 and 2, this high-pressure hose was fitted with fittings (not shown) at both ends, filled with hydraulic oil, and heated and aged at 120°C for 24 hours. A bulge occurred and the hose did not perform well as a high pressure hose.

〔Effect of the invention〕

As described above, in the present invention, the inner tube rubber or adhesive rubber layer is based on an ethylene-based saturated polymer such as chlorinated polyethylene (CM) or chlorosulfonated polyethylene (CSM), which has excellent heat resistance, and Because the heat-resistant high-pressure hose of the present invention is firmly bonded to the brass-plated pressure-resistant reinforcing steel wire, even if the hose is continuously used at oil temperatures of 120 to 150 degrees Celsius and subjected to severe repeated bending, It has been used for more than 1,000 hours, and there have been no abnormal phenomena such as cracks on the inner surface or oil leakage from the fitting attachment part, so it has excellent heat resistance, oil resistance, and pressure resistance, and is suitable as a high temperature and high pressure hose. It has sufficient performance.

Therefore, the high-pressure hose of the present invention greatly reduces downtime due to oil leaks, reduces the need for spare parts, etc.
The economic effect is significant.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are perspective views showing an embodiment of the heat-resistant high-pressure hose of the present invention, and are cut away in stages. 1, 2... Inner tube rubber, 3... Adhesive rubber layer, 4, 6...
Pressure-resistant reinforcing steel wire layer, 5... intermediate rubber, 7... outer tube rubber.

Claims (1)

[Scope of Claims] 1. A high-pressure hose having an inner tube rubber as an inner layer, a brass-plated pressure-resistant reinforcing steel wire layer as an intermediate layer, and an outer tube rubber as an outer layer, which is obtained by heat crosslinking. Tube rubber becomes ethylene-based saturated polymer,
A heat-resistant high-pressure hose characterized by being made of a polymer composition containing an organic peroxide, an epoxy resin, and trimercaptotriazine. 2. A high-pressure hose obtained by heat crosslinking, which has an inner tube rubber made of an ethylene-based saturated polymer as an inner layer, a pressure-resistant reinforcing steel wire layer plated with brass as an intermediate layer, and an outer tube rubber as an outer layer. An adhesive rubber layer made of a polymer composition containing an ethylene-based saturated polymer, an organic peroxide, an epoxy resin, and a trimercaptotriazine is provided between the tube rubber and the brass-plated pressure-resistant reinforcing steel wire layer. A heat-resistant high-pressure hose with special features.