JPS5952065B2 - rubber hose - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rubber hose having an oil-resistant inner tube layer with excellent properties such as resistance to deterioration in gasoline and cold resistance, and is suitable for use as fuel hoses for automobiles and the like.

Modern fuel circuit hoses, especially automotive fuel hoses that are applied to fuel circuit systems equipped with electronic fuel injection devices, are susceptible to deterioration due to the gasoline flowing inside them as the engine heats up or the internal pressure increases. Gasoline properties are required.

Furthermore, with the spread of automobiles in extremely cold regions, a high degree of cold resistance is also required. In view of the above, an object of the present invention is to provide a rubber hose having an oil-resistant inner tube layer with excellent characteristics such as resistance to deterioration of gasoline and cold resistance.

The rubber hose of the present invention is a vulcanizate of a partially hydrogenated unsaturated nitrile-conjugated diene copolymer rubber in which the conjugated diene unit portion is hydrogenated, or a rubber composition in which a vinyl chloride resin is mixed with this copolymer rubber. The above object is achieved by forming the inner tube layer with a vulcanized product of the present invention. Hereinafter, the rubber hose of the present invention will be explained based on illustrated examples.

Here, explanation will be given by taking as an example a fuel hose with a three-layer structure consisting of an inner tube layer 1, a braided reinforcing yarn layer 2, and an outer tube layer 3 as shown in FIG. Alternatively, the present invention is applicable to various rubber hoses consisting of two or more layers.

The inner pipe layer 1 of the fuel hose is made of partially hydrogenated unsaturated nitrile.
Conjugated diene copolymer rubber (hereinafter referred to as "H-added NBR"), or vinyl chloride-based resin (hereinafter referred to as "H-added NBR") to this H-added NBR
It is made of a vulcanized rubber composition mixed with PVC.

The above-mentioned H-added NBR is obtained by hydrogenating at least 50% of the conjugated diene unit portion of an unsaturated nitrile-conjugated diene copolymer rubber produced by emulsion polymerization or solution polymerization using a conventional method.

The above-mentioned copolymer rubber to be hydrogenated is composed of an unsaturated nitrile such as acrylonitrile or methacrylonitrile and 1.3
-Copolymerized with at least one conjugated diene such as butadiene, isoprene, 1,3-pentadiene, etc., or a part of the conjugated diene is combined with methyl esters such as acrylic acid, methacrylic acid, fumaric acid, itaconic acid, etc. It is a product obtained by copolymerizing an unsaturated carboxylic acid ester such as ester, 2-ethylhexyl ester, or a substance substituted with N-methylolacrylamide with the above-mentioned unsaturated nitrile.

Specifically, acrylonitrile-butadiene copolymer rubber, acrylonitrile-isoprene copolymer rubber, acrylonitrile-butadiene-isoprene copolymer rubber, acrylonitrile-butadiene-methyl acrylate copolymer rubber, atarylonitrile-butadiene-butyl acrylate copolymer rubber, etc. For example, acrylonitrile-
Butadiene copolymer rubber is most suitable. Above H addition N
The amount of bonded unsaturated nitrile in BR is usually 10 to 70 wt%
, compatibility with the PVC to be mixed, purpose of use (application)
It is determined as appropriate within the above range depending on the situation.

Further, if the degree of hydrogenation of the conjugated diene unit portion is less than 50%, the various physical properties targeted by the present invention cannot be obtained.

The upper limit of the hydrogenation degree may be 100%, but in the case of sulfur-based vulcanization, the hydrogenation degree is set to 98% or less in view of the relationship with the vulcanization rate. The PVC used is polyvinyl chloride or a copolymer of vinyl chloride and a monoolefin monomer such as vinyl acetate. is 20wt%
Before and after.

If the amount is less than 5 wt%, there is no effect of adding PVC.

The amount of PVC to be blended is determined by the fact that as the amount of PVC increases, the resin properties become stronger, and there is a limit at which the rubber properties are impaired even if vulcanization is possible. The required performance may be determined as appropriate. H
Added NBRI:. The method of mixing PVC is not particularly limited, but methods such as kneading using rolls or a Banbury mixer, or dispersion mixing in a liquid, coprecipitation, and drying are used. The above H-added NBR or this H-added NB
R.I.:. Each raw material rubber mixed with PVC contains various commonly used auxiliary materials, such as inorganic fillers such as carbon black, silica, and metal oxides, and organic fillers such as lignin, as well as softeners, plasticizers, and oxidants. Inhibitors, colorants, etc. are blended as appropriate, and further a sulfur-based or peroxide-based vulcanizing agent is appropriately added and kneaded.

This rubber material is used to extrude the inner tube layer 1 using an extruder, then the braided reinforcing yarn layer 2 is formed, and after applying adhesive, the inner tube layer 1 is extruded.
Extrude the outer tube layer 3 using a machine. At this time, the rubber material for the outer tube layer is not particularly limited, but for example, CSM, which has good weather resistance.
CR. Use synthetic rubber such as CHR. Vulcanization conditions are 30 to 90 minutes at a temperature of 145 to 170°C. The fuel hose manufactured in this way was manufactured using conventional acrylonitrile-butazinine copolymer rubber (NBR), as shown in the examples below.
) or a PVC mixed rubber vulcanizate thereof, the inner layer is particularly excellent in resistance to deteriorated gasoline and cold resistance, and also has good physical properties in normal state. The rubber hose of the present invention is not limited to the above-mentioned fuel hose, but can also be used in a control circuit of a carburetor etc. that utilizes the negative pressure generated in the intake manifold of an engine, and can be used as a hose through which gasoline paper flows, or as an engine. It is resistant to products of oxidative deterioration of engine oil due to high temperatures, so it can also be applied to pressure transmission circuit hoses through which mineral oil-based oil flows, such as power steering oil, torque converter, and air brake hoses. .

Examples will be described below along with comparative examples to confirm the effects of the present invention.

Each test piece of Examples and Comparative Examples was prepared by extruding each rubber material having the formulation shown in Table 1 into a tube with an outer diameter of 9.5 mmφ (wall thickness of 1.0 mm) using an extruder, and heating it at 150°C x 30°C.
Vulcanization was carried out at min., and each test piece was punched out from this vulcanizate, and various physical property tests were conducted using the methods described below. The test results are shown in Table 2.

(A) Normal state physical properties Breaking strength (TB), Breaking elongation (EB)...JI
Measured using SK63Ol (Tampel type No. 3).

Hardness: JISA hardness JISK-6
Measured using 301. (B) 70℃ JIS containing 1wt% of deterioration-resistant gasoline lauroyl peroxide
A tampel-shaped test piece (size 6/10 of JIS No. 3 in length) is continuously immersed in Fuel C solution while refreshing the solution every 24 hours (1 cycle).

After each indicated cycle, a test piece was taken out, left at room temperature for 24 hours, and then dried at 60°C under reduced pressure.
) were each measured according to JISK-6301. (
O Cold resistance impact embrittlement temperature was measured according to JISK-6301. Ta.

(D Heat aging resistance Tampel type J after being left in an atmosphere of 120℃ x 70 hours
Breaking strength, breaking elongation and hardness of IS3 test pieces
ΔH. , △TB, △EB.

(E) Crack Growth Resistance A tampel-type JISI No. test specimen was marked with marked lines at 40 mm intervals, a crack with a width of 203 mm was made in the center, and the test piece was elongated by 50% (60 mm between marked lines) using an appropriate instrument. The test piece given this elongation was immersed in JIS Fuel D, and the time until the test piece broke was measured.

(F) Gasoline resistance A test piece measuring 20 x 20 x 1 mm was immersed in JIS Fuel C at 40°C for 48 hours, the volume before and after immersion was measured, and the rate of change (ΔV) was displayed.

0 Califol resistance A 20 x 20 x 1 mmt test piece was heated with methanol 20v0.
It was immersed in 40'CJIS Fuel C containing 1% for 48 hours, the volume before and after immersion was measured, and the rate of change (ΔV) was displayed.

From the results in Table 2, it can be seen that the inner tube layer of the rubber hose of the present invention (Examples 1 to 6) has excellent resistance to deterioration gasoline and cold resistance, and also has normal physical properties when formed of ordinary NBR etc. (Comparative Example 1) ~
The physical properties are well balanced, if not better than 3).

Also, H-added NBR! : When the inner layer was formed from a rubber material mixed with PVC (Examples 2 to 6), physical properties such as normal physical properties and resistance to deteriorated gasoline were improved compared to when it was formed from only H-added NBR (Example 1). It can be seen that there is further improvement.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a rubber hose to which the present invention is applied. 1: Inner tube layer, 2: Braided reinforcing yarn layer, 3: Outer tube layer.

Claims (1)

[Scope of Claims] 1. The inner tube layer is formed of a vulcanizate of a partially hydrogenated unsaturated nitrile-conjugated diene copolymer rubber in which at least 50% of the conjugated diene units are hydrogenated. rubber hose. 2. Vulcanization of a rubber composition in which 5 wt% or more (inner portion) of a vinyl chloride resin is mixed with a partially hydrogenated unsaturated nitrile-conjugated diene copolymer rubber in which at least 50% of the conjugated diene units are hydrogenated. A rubber hose characterized by an inner tube layer made of a material.