JP2003096241A - Rubber composition and power steering hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition which has high heat resistance and high vibration absorbing capability and which is used for a power steering hose and the like. SOLUTION: The rubber composition contains 90-20 pts.wt. of (1) a copolymer rubber containing in the polymer chain 10-45 wt.% of unit portions from an unsaturated nitrile (Y portions; VCN), 0-5 wt.% of unit portions from a conjugated diene (Z portions, C=C), 90-50 wt.% of the unit portions resulting from hydrogenation of unit portions from an ethylenically unsaturated monomer other than the unsaturated nitrile and/or of unit portions from a conjugated diene (X portions; C-C), (2) 10-80 pts.wt. of a chlorinated polyethylene rubber having a chlorination ratio of 25% or more, and (3) an organic peroxide. The composition is characterized in that the loss tangent (tanδ) at applying forced extension vibration of 5 Hz is 0.23 or more in the temperature range of 0-10 deg.C.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rubber composition having high heat resistance and high vibration absorption performance. Also,
The present invention relates to a power steering hose using the above rubber composition, which has high heat resistance and high vibration absorption performance.

[0002]

2. Description of the Related Art A power steering hose is a hose used in a power steering circuit for the purpose of transmitting hydraulic pressure and attenuating hydraulic pump drive noise (noise due to pulsating pressure generated from a hydraulic pump). Among them, the power steering hose for automobiles plays a large role in absorbing the vibration generated by the compressor of the hydraulic pump, keeping the interior of the vehicle quiet, and reducing the minute vibrations felt by the body, and the vibration absorption performance is strongly demanded. There is. The vibration absorption performance of the power steering hose depends on the structure of the power steering hose itself and the entire system including the power steering hose, constituent members, etc., but it is known that the characteristics of the rubber member constituting the power steering hose are greatly affected. ing. Therefore, in order to improve the vibration absorption performance of the power steering hose, it is one of effective means to improve the vibration absorption performance of the rubber member constituting the power steering hose.

A power steering hose for an automobile is arranged in an engine room of the automobile. In recent years, the temperature of the engine room has been increasing due to downsizing of the engine room, higher output of the engine, etc., and the power steering hose is often exposed to a high temperature environment of about 140 ° C. Therefore, high heat resistance is required for the constituent members of the power steering hose.

As described above, the rubber member constituting the power steering hose is required to have high heat resistance and high vibration absorption performance, and a rubber composition satisfying both characteristics and these rubber compositions are used. Various power steering hoses have been proposed. However, the required standards for both characteristics are increasing day by day. Further, other properties required for the rubber composition and the power steering hose using these rubber compositions, for example, physical properties such as strength properties and chemical properties such as oil resistance must be maintained. For these reasons, it is extremely difficult to optimize the composition of the rubber composition, the structure of the power steering hose, the constituent members, etc. that satisfy both characteristics at a high level. No compositions and power steering hoses have been obtained.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition having high heat resistance and high vibration absorption performance, which can be suitably used for a power steering hose and the like. Another object of the present invention is to provide a power steering hose having high heat resistance and high vibration absorption performance.

[0006]

Means for Solving the Problems That is, the present invention provides (1)
A unit portion (Y portion;
VCN) 10 to 45% by weight, unit portion from conjugated diene (Z portion; C = C) 0 to 5% by weight and unit portion from ethylenically unsaturated monomer other than unsaturated nitrile and / or from conjugated diene 90 to 20 parts by weight of a copolymer rubber having 90 to 50% by weight of a unit part (X part; C to C) obtained by hydrogenating the unit part of (1), and 80 parts by weight and (3) an organic peroxide are contained, and a loss angle tangent (tan δ) at the time of forced extension vibration of 5 Hz is 0.23 or more in a temperature range of 0 to 10 ° C. And a rubber composition.

Further, the present invention provides a power steering hose comprising at least an inner pipe, a reinforcing layer and an outer pipe, wherein the above rubber composition is used for at least one layer constituting the inner pipe.

The reinforcing layer has a braided structure of at least two layers made of a fiber material, the first braided layer located immediately above the inner layer has a braided angle of 47 to 51 °, and the second braided layer located further thereon. The braid angle of the layers is preferably 54-58 °.

[0009] It is preferable that the elongation of the fiber material used for at least one reinforcing layer among the above-mentioned fiber materials when stretched by a stress corresponding to the working pressure is 2% or more.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.

In the present invention, (1) 10 to 45% by weight of a unit portion (Y portion; VCN) from an unsaturated nitrile and 0 to 45% by weight of a conjugated diene (Z portion; C = C) in a polymer chain.
5% by weight and a hydrogenated unit portion from an ethylenically unsaturated monomer other than unsaturated nitrile and / or a conjugated diene (X portion; C—C) 9
90 to 20 parts by weight of a copolymer rubber having 0 to 50% by weight, (2) 10 to 80 parts by weight of a chlorinated polyethylene rubber having a chlorination rate of 25% or more, and (3) an organic peroxide, Loss tangent (tan δ) during 5 Hz forced extension vibration
Is 0.23 or more in a temperature range of 0 to 10 ° C., which is a rubber composition. Hereinafter, the rubber composition of the present invention will be described.

The rubber composition of the present invention comprises, as polymer components, (1) 90 to 20 parts by weight of a predetermined copolymer rubber and (2)
Chlorinated polyethylene rubber with a chlorination rate of 25% or more 10-8
And 0 parts by weight.

Generally, it is obtained by hydrogenating a copolymer rubber of acrylonitrile and butadiene, and it is a unit part from an unsaturated nitrile (Y part; VCN, AN), a unit part from a conjugated diene (Z part; C = C). , And a hydrogenated unit moiety from an ethylenically unsaturated monomer other than unsaturated nitrile and a conjugated diene (X
Copolymer rubbers comprising a portion; C-C) are known. Hereinafter, the copolymer rubber will be referred to as hydrogenated acrylonitrile-butadiene copolymer rubber.

The hydrogenated acrylonitrile-butadiene copolymer rubber used in the present invention contributes to the high heat resistance of the rubber composition of the present invention. It also has the effect of increasing the oil resistance of the rubber composition of the present invention.

The hydrogenated acrylonitrile-butadiene copolymer rubber used in the present invention comprises 10 to 45% by weight of a unit portion (Y portion; VCN) from an unsaturated nitrile and a unit portion (Z from a conjugated diene) in the polymer chain. Part; C = C) 0
5% by weight and a hydrogenated unit portion from an ethylenically unsaturated monomer other than unsaturated nitrile and / or a conjugated diene (X portion; C—C) 9
It is a copolymer rubber having 0 to 50% by weight. When the composition of the hydrogenated acrylonitrile-butadiene copolymer rubber is within the above range, the oil resistance and heat resistance are excellent. For example, when the Z portion of the hydrogenated acrylonitrile-butadiene copolymer rubber exceeds 5% by weight, the heat resistance of the rubber composition may be insufficient. The content of hydrogenated acrylonitrile-butadiene copolymer rubber in the polymer component of the rubber composition of the present invention is 90 to 20 parts by weight, preferably 70 to 30 parts by weight. If it exceeds 90 parts by weight, the content of the chlorinated polyethylene rubber that contributes to the high vibration absorption performance of the rubber composition decreases as described later, and the vibration absorption performance of the rubber composition may become insufficient. If it is less than 20 parts by weight, the heat resistance of the rubber composition may be insufficient. 70
When it is from 30 parts by weight, the balance of the vibration absorption performance, heat resistance and other physical properties of the rubber composition becomes more suitable.

The chlorinated polyethylene rubber used in the present invention contributes to the high vibration absorbing performance of the rubber composition. This is considered to be due to energy absorption that occurs when the segment containing the chlorine atom in the chlorinated polyethylene rubber restores the Micro Brownian motion.

The chlorinated polyethylene rubber used in the present invention has a chlorination rate of 25% or more, preferably 30 to 35%.
Is. Here, the chlorination rate means the ratio of the weight of chlorine atoms to the weight of the entire chlorinated polyethylene rubber. When the chlorination rate of the chlorinated polyethylene rubber is less than 25%, as will be described later, the loss angle tangent (tan δ) of the rubber composition during 5 Hz forced extension vibration is 0. It may be difficult to set the value to 23 or more, and the vibration absorption performance of the rubber composition may be insufficient. The content of the chlorinated polyethylene rubber having a chlorination rate of 25% or more in the polymer used in the rubber composition of the present invention is 1
It is 0 to 80 parts by weight, preferably 30 to 70 parts by weight.
If it exceeds 80 parts by weight, the content of the hydrogenated acrylonitrile-butadiene copolymer rubber that contributes to the heat resistance of the rubber composition becomes small as described above, and the heat resistance of the rubber composition may become insufficient. If it is less than 10 parts by weight, the vibration absorption performance of the rubber composition may be insufficient. Three
When it is 0 to 70 parts by weight, the vibration absorbing performance of the rubber composition,
The balance between heat resistance and other physical properties becomes more suitable.

The rubber composition of the present invention contains, as a polymer component, a polymer other than the above hydrogenated acrylonitrile-butadiene copolymer rubber and the above chlorinated polyethylene rubber having a chlorination rate of 25% or more with high heat resistance and high vibration absorption performance. Can be appropriately contained within a range that does not impair the above. For example, ethylene-propylene copolymer rubber (EPM), ethylene-propylene-diene copolymer rubber (EPDM),
Ethylene acrylic ester copolymer rubber (AEM), ethylene-vinyl acetate copolymer rubber (EVM), ethylene-
Acrylic ester-vinyl acetate copolymer rubber and the like can be contained as appropriate.

The organic peroxide (3) used in the rubber composition of the present invention is not particularly limited as long as it is generally used for rubber cross-linking. For example, dicumyl peroxide, ditertiarybutyl peroxide, 1,3 -Bis (t-butylperoxyisopropyl) benzene, 4,
N-butyl 4'-di (t-butylperoxy) valerate,
2,5-dimethyl-2,5-di (t-butylperoxy) hexane can be mentioned. The content of the organic peroxide in the rubber composition of the present invention is preferably 1 to 10 parts by weight based on 100 parts by weight of the polymer component of the rubber composition of the present invention. If the amount is less than 1 part by weight, the crosslink density may be low and the modulus or the like may be impaired. If it exceeds 10 parts by weight, the crosslink density becomes high and the elongation at break may become low.

In addition to the above components, the rubber composition of the present invention may further contain additives such as a reinforcing agent such as carbon black, a filler, an antioxidant, a processing aid, a plasticizer and a softening agent, if necessary. It can be blended.

Examples of the filler include calcium carbonate, barium sulfate, talc, clay, titanium oxide and silica.

As the antiaging agent, for example, N- (1,
3-Dimethylbutyl) -N'-phenyl-p-phenylenediamine (6PPD), N, N'-dinaphthyl-p-
Phenylenediamine (DNPD), N-isopropyl-
N'-phenyl-p-phenylenediamine (IPP
D) and styrenated phenol (SP).

Examples of the softening agent include process oil and vegetable oil. Examples of the plasticizer include synthetic plasticizers such as phthalic acid ester, adipic acid ester, fatty acid ester, and trimellitic acid ester; and liquid rubber.

The rubber composition of the present invention has a loss angle tangent (tan δ) of 0.23 or more, preferably 0.25 or more in a temperature range of 0 to 10 ° C. when it is subjected to forced extension and vibration at 5 Hz. The reason will be described below.

The rubber composition used for the rubber member constituting the power steering hose has a composition of about 80 to 5 at a working temperature of the power steering hose of about 20 ° C.
It is required to have excellent absorption performance for vibration in the frequency band of 00 Hz. It is in this frequency band that humans perceive as noise and vibration in the interior of automobiles.

As a result of intensive studies by the present inventors, the loss angle tangent (tan δ) of the rubber composition when the vibration was applied to the rubber composition in the frequency band of about 80 to 500 Hz at about 20 ° C. was 0. It has been found that when it is 23 or more, preferably 0.25 or more, the vibration absorption performance of the rubber composition when used in a power steering hose is excellent. However, when measuring the loss tangent (tan δ) of the rubber composition at about 20 ° C. while changing the frequency of vibration applied to the rubber composition to about 80 to 500 Hz, a special measuring device developed in recent years is required. is there. Generally, since the natural frequency of the measuring device itself is in the above frequency band, there are restrictions on the measuring device such that resonance occurs in the measuring system and accurate measurement is difficult. Therefore, it is not industrially practical to use this index as an index to determine the composition of the rubber composition and to use it for quality control at the production site. The present inventors have considered replacing the above-mentioned measurement with one that can be easily carried out industrially in order to eliminate the above-mentioned inconvenience. That is, the measured value of viscoelasticity can be mutually converted between temperature and frequency, and the temperature-time conversion rule (WLF formula: ML Williams et a.
l. J. Amer. Chem. Soc. , 77, 37
01 (1952)), the loss angle tangent (tan δ) of the rubber composition was measured at a constant frequency in a narrow temperature range. It was found that the loss tangent (tan δ) can be estimated. Specifically, a formula based on the following WLF formula was used.

Log (a _T ) = − C ₁ (T−T ₀ ) / (C ₂ + T−T ₀ ) = α; WLF equation where a _T (shift factor) = ω ₂ / ω ₁ = 2πf ₂ / 2πf ₁ = f ₂ / f ₁ T = T ₀ −αC ₂ / (α + C ₁ ) C ₁ (constant) = 8.86 C ₂ (constant) = 101.6

Substituting the values (f ₁ and f ₂ ) shown in Table 1 into these equations, temperature: 20 ° C., frequency band: 80
Measurement conditions of up to 500 Hz can be converted into measurement conditions that can be measured in the laboratory. As an example, frequency: 5H
z, temperature range: measurement conditions of 7.8 to 1.3 ° C. (about 8 to 1 ° C.) were obtained (Table 1).

[0029]

[Table 1]

By using the above-obtained conditions, the measurement can be carried out easily in a short time, which is extremely useful for determining the composition of the rubber composition, quality control at the production site and the like.
That is, if the loss angle tangent (tan δ) of the rubber composition measured under the conditions of frequency: 5 Hz, temperature range: about 10 to 0 ° C. is 0.23 or more, temperature: about 20 ° C., frequency range:
The loss angle tangent (tan δ) of the rubber composition when measured under the condition of about 80 to 500 Hz is 0.23 or more,
It can be seen that the rubber composition has the ability to absorb vibrations that humans perceive as noise and the like in the interior of a car.

Therefore, as described above, the rubber composition of the present invention has a loss angle tangent (t
It is necessary that an δ) is 0.23 or more, preferably 0.25 or more in the temperature range of 0 to 10 ° C.

Since the rubber composition of the present invention has high heat resistance and high vibration absorption performance, it is suitably used for a wide range of applications, and is more suitable for a rubber member constituting a power steering hose, particularly a power steering hose for automobiles. It is preferably used.

The present invention is a hose having at least an inner tube, a reinforcing layer and an outer tube, wherein at least one layer of the inner tube is composed of the above rubber composition, which is a power steering hose. . Hereinafter, the power steering hose of the present invention will be described.

The power steering hose of the present invention has at least an inner pipe, a reinforcing layer and an outer pipe. At least one layer of the inner tube is made of the above rubber composition having high vibration absorption performance. For this reason, the vibration caused by the compressor of the hydraulic pump can be absorbed by the inner pipe of the power steering hose. As long as these conditions are satisfied, the power steering hose of the present invention is not particularly limited by the structure, material, manufacturing method and the like.

As a material for the inner tube and the outer tube other than the layer composed of the rubber composition of the present invention, a generally used rubber composition, resin or the like may be used as long as it has good heat resistance. It is possible to use two or more kinds in combination or in combination. Examples of the raw material rubber of the rubber composition include hydrogenated acrylonitrile-butadiene copolymer rubber (HNBR) and styrene-butadiene copolymer rubber (SB
R) and chlorosulfonated polyethylene rubber (CSM). In the rubber composition, in addition to the raw rubber, a vulcanizing agent,
A filler, a reinforcing agent, a plasticizer, an antiaging agent, a vulcanization accelerator, a softening agent, a tackifier, a lubricant, a dispersant, a processing aid and the like may be appropriately blended. Examples of the resin include nylon and aromatic polyamide resins.

The structure and material of the reinforcing layer can be appropriately selected according to the structure of the power steering hose of the present invention. For example, the reinforcing layer may be one layer or two or more layers, and may have a structure such as a blade structure or a spiral structure. As the material forming the reinforcing layer, reinforcing yarn (reinforcing fiber), reinforcing wire, or the like can be used. Examples of the reinforcing yarn include aramid fiber, nylon, rayon, polyamide, vinylon, and polyester yarn. As the reinforcing wire, for example,
Examples include brass-plated or zinc-plated wires for rust prevention and adhesion. Also, 2 reinforcement layers
When it is composed of more than one layer, it is preferable to use an interlayer rubber between the layers of the reinforcing layer.

When the reinforcing layer has a braided structure of at least two layers made of a fibrous material, the first layer located immediately above the inner layer
It is preferable that the braid angle of the braid layer is 47 to 51 °, and the braid angle of the second braid layer located thereabove is 54 to 58 °.

Further, it is preferable that the elongation of the fiber material used for at least one reinforcing layer among the above-mentioned fiber materials when stretched by a stress corresponding to the working pressure is 2% or more. Here, the stress corresponding to the working pressure means the stress that the reinforcing layer receives in the circumferential direction when the fluid passes through the inside of the hose when the hose is used. It is more preferable that the elongation of the fiber material used for all the reinforcing layers when stretched by a stress corresponding to the working pressure is 2% or more.

The inner diameter, outer diameter and length of the power steering hose of the present invention are not particularly limited.

The method of manufacturing the power steering hose of the present invention is not particularly limited, and a conventionally known method of manufacturing a hose can be used. For example, an unvulcanized composition of the present invention is extruded from an extruder onto a mandrel coated with a release agent in advance to form an inner tube. Next, an adhesive is applied on the inner pipe as required, and the reinforcing yarn or the reinforcing wire is braided on the inner pipe using a braiding machine. If necessary, an adhesive is applied on the reinforcing layer for adhesion to the outer tube, and then the composition of the present invention is extruded by an extruder to form an outer tube. Pressure is applied directly or by wrapping the hose with tape or the like, and then pressure is applied for vulcanization. Finally, the mandrel is pulled out to obtain the power steering hose of the present invention. Examples of the adhesive used in the above case include isocyanate-based, urethane-based, phenol resin-based, resorcin-based, and chlorinated rubber-based adhesives.

The power steering hose of the present invention can be suitably used for both a high-voltage power steering hose and a low-voltage power steering hose, and since it has high heat resistance and high vibration absorption performance, it is extremely useful.

[0042]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. <Preparation of Rubber Composition> The raw materials shown below were used in the amounts shown in Table 2 to obtain the rubber compositions shown in Table 2. (1) Hydrogenated acrylonitrile-butadiene copolymer rubber (HNBR): A unit part (Y part;
VCN, AN) 33.0% by weight, unit portion from conjugated diene (Z portion; C = C) 1.3% by weight and unit portion from ethylenically unsaturated monomer other than unsaturated nitrile and conjugated diene Having 65.7% by weight of the unit portion (X portion; C—C) obtained by hydrogenating the unit portion of Y portion 33.0% by weight, Z portion 6.7% by weight and X portion
Part having 60.3% by weight (2) Chlorinated polyethylene rubber (CM): Chlorination rate 35.0% Chlorination rate 20.0%

(3) Organic peroxide 1,3-bis (t-butylperoxyisopropyl) benzene: Percadox 14/40, manufactured by Kayaku Akzo Co., Ltd.
40 wt% content (4) Compounding agent SRF grade carbon black: Asahi # 50, magnesium oxide (MgO) manufactured by Asahi Carbon Co. Stearic acid anti-aging agent: Noward 445, Uniroyal anti-aging agent: Nocrac MBZ, Ouchi Shinko Chemical's Wax (WAX): Sun Wax 171P, Sanyo Kasei's Triallyl Isocyanurate (TAIC) Plasticizer: ADEKAIZER C9N, Asahi Denka's Diallyl Phthalate (DAP) Epoxy Resin: Sumiepoxy ELA-115, Sumitomo Chemical Co., Ltd. Company

The following tests were carried out on the rubber composition obtained as described above. <Dynamic viscoelasticity test> Using a test material of a rubber composition having a thickness of 2.0 mm, a temperature of 0 ° C. during forced extension vibration with a frequency of 5 Hz,
The loss angle tangent (tan δ) at 5 ° C and 10 ° C was measured (according to JIS6900). <Heat resistance test> Air heating aging treatment was performed under the conditions of 150 ° C and 168 hours. The elongation at break before and after the treatment was measured according to the method described in JIS K6251 to calculate the rate of change in elongation at break (ΔE _B ) due to the treatment.

The results of the dynamic viscoelasticity test are shown in Table 2. The rubber composition of the present invention has a loss tangent (tan δ) of 0.23 or more in a temperature range of 0 to 10 ° C. at the time of forced extension and vibration of 5 Hz, and is required when used for a power steering hose or the like. It can be seen that the vibration absorption performance is excellent. In addition, the chlorinated polyethylene rubber (C
The relationship between the M) content and the loss tangent (tan δ) is shown in FIG. It can be seen that the greater the CM content of the rubber composition, the greater the loss angle tangent (tan δ) and the better the vibration absorption performance.

The results of the heat resistance test are shown in Table 2. If the absolute value of the change rate of break elongation (ΔE _B ) is 70% or less,
It means that it has heat resistance. The rubber composition of the present invention is
It can be seen that it has excellent heat resistance. In addition, hydrogenated acrylonitrile-butadiene copolymer rubber (HNB
Fig. 2 shows the relationship between the R) content and the rate of change in break elongation (ΔE _B ).
Shown in. It can be seen that the larger the HNBR content of the rubber composition, the smaller the absolute value of the change rate of elongation at break, and the better the heat resistance.

<Production of Power Steering Hose> A power steering hose was produced using the materials shown below. (1) Inner tube Each rubber composition 1 obtained above (2) Reinforcing layer Wire layer (first layer) Nylon fiber interlayer rubber Rubber obtained by using the raw materials shown below in the amounts shown in Table 3 Composition 2 Acrylonitrile-butadiene copolymer rubber (NBR):
Nipol 1042, Nippon Zeon SRF grade carbon black: Asahi # 50, Asahi Carbon Silica: Nipseal VN3, Nippon Silica Industry Co., Ltd. zinc oxide (ZnO) stearic acid resorcinol cross-linking agent (2,4,6-trimercapto- 1,3,5-triazine): ZISNET-F, dioctyl phthalate (DOP) manufactured by Sankyo Kasei Co., Ltd. Sulfur accelerator CZ: Sunceller CM-PO, hexamethylenetetramine wire layer (second layer) manufactured by Sanshin Chemical Industry Co., Ltd. Nylon Fibers: those with an elongation of 2.2% and 1.5% when pulled at 7.8 MPa (stress equivalent to the working pressure)

(3) Outer tube Rubber composition 3 obtained by using the raw materials shown below in the amounts shown in Table 4 Chlorosulfonated polyethylene rubber (CSM): Hypalon 40, SRF grade carbon black manufactured by DuPont: Asahi # 50, magnesium oxide (MgO) AC polyethylene anti-aging agent manufactured by Asahi Carbon Co., Ltd .: Nocrac NBC, dioctyl phthalate (DOP) litharge (PbO) promoter TRA: Suncella TRA, Sanshin Chemical Co., Ltd. Made

Outer diameter of 9.6 m coated with a release agent in advance
Rubber composition 1 using a rubber extruder on a m mandrel
Was extruded to form an inner tube. Next, nylon fibers were braided on the inner tube at the angles shown in Table 5, and the wire layer (first
Layer), and the rubber composition 2 is extruded thereon using a resin extruder, an interlayer rubber is put therein, and nylon fibers are braided thereon at an angle shown in Table 5 to form a wire layer (second layer). To form a reinforcing layer. Further, the rubber composition 3 was extruded on the reinforcing layer using a resin extruder to form an outer tube. Finally, the mandrel was pulled out to obtain each power steering hose shown in Table 5. Each power steering hose had an inner diameter of 9.6 mm and an outer diameter of 17.5 mm.

The following tests were carried out on the power steering hose obtained as described above. <Volume Expansion> The volume expansion was measured under the conditions of 20 ° C. and 5.9 MPa. <Vibration absorption performance test> The power steering hose is filled with air to an internal pressure of 4.9 MPa, immersed in a container filled with oil at 50 ° C, and the vibration is applied to the oil by a compression wave to cause vibration. The first resonance point (Hz) was measured by vibrating while changing the number. <High temperature impact pressure test> According to JIS 6330, temperature 130 ° C., pressure 11.8 MPa, impact frequency 30
A high temperature impact pressure test was performed under the condition of 0,000 times.

Table 5 shows the measurement results of the volume expansion amount.

The results of the vibration absorption performance test are shown in Table 5.
If the frequency at the primary resonance point is 100 Hz or less, it means that there is vibration absorption performance. It can be seen that the power steering hose of the present invention has excellent vibration absorbing performance.
FIG. 3 shows the relationship between the chlorinated polyethylene rubber (CM) content of the rubber composition and the frequency at the primary resonance point of the power steering hose when the thickness of the inner tube of the power steering hose is constant. It can be seen that the higher the CM content of the rubber composition, the lower the frequency of the primary resonance point of the power steering hose and the better the vibration absorption performance.

The results of the high temperature impact pressure test are shown in Table 5.
It can be seen that the power steering hose of the present invention is not broken by the high temperature impact pressure test and is excellent in heat resistance.

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

[Table 5]

[0058]

Since the rubber composition of the present invention has high heat resistance and high vibration absorption performance, it is suitable for a wide range of applications and is suitable for a rubber member constituting a power steering hose, particularly a power steering hose for automobiles. , More preferably used. Further, the power steering hose of the present invention is extremely useful because it has high heat resistance and high vibration absorption performance, and can be particularly suitably used as a power steering hose for automobiles.

[Brief description of drawings]

FIG. 1 shows a chlorinated polyethylene rubber (C
7 is a graph showing the relationship between M) content and loss angle tangent (tan δ).

FIG. 2 is a graph showing the relationship between the hydrogenated acrylonitrile-butadiene copolymer rubber (HNBR) content of the rubber composition and the change rate of elongation at break (ΔE _B ).

FIG. 3 shows a chlorinated polyethylene rubber (C
M) A graph showing the relationship between the content and the frequency at the primary resonance point of the power steering hose.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeshi Inoue             2-1, Oiwake, Hiratsuka-shi, Kanagawa Yokohama Rubber Co., Ltd.             Ceremony Company Hiratsuka Factory F-term (reference) 3D033 ED02                 4J002 AC11W BB24X EK036 FD010                       FD020 FD030 FD146 GN00

Claims (4)

[Claims] (1) 10 to 45% by weight of a unit portion (Y portion; VCN) from an unsaturated nitrile, 0 to 5% by weight of a unit portion (Z portion; C = C) from a conjugated diene in a polymer chain. % And 90 to 50% by weight of a hydrogenated unit moiety from an ethylenically unsaturated monomer other than unsaturated nitrile and / or a conjugated diene. 90 to 20 parts by weight of rubber, and (2) chlorinated polyethylene rubber having a chlorination rate of 25% or more 1
0 to 80 parts by weight and (3) an organic peroxide are contained, and a loss angle tangent (tan δ) at the time of forced extension vibration of 5 Hz is 0.23 or more in a temperature range of 0 to 10 ° C. A rubber composition comprising: 2. A hose having at least an inner tube, a reinforcing layer and an outer tube, wherein at least one layer of the inner tube is a hose.
A power steering hose comprising the rubber composition as described in 1. 3. The reinforcing layer has a braided structure of at least two layers made of a fibrous material, the braided angle of the first braided layer located immediately above the inner layer is 47 to 51 °, and the braided angle is further above it. The power steering hose according to claim 2, wherein the braid angle of the two braid layers is 54 to 58 °. 4. The elongation according to claim 3, which is 2% or more when stretched by a stress corresponding to a working pressure of a fiber material used for at least one reinforcing layer among the fiber materials. Power steering hose.