JP2006170343A - Automobile hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automobile hose having sufficient ozone resistance without containing halogen containing materials including a vinyl chloride resin which causes environmental problems. <P>SOLUTION: The automobile hose is formed in two or more layers. The inner layer is formed of a rubber composition using as a polymer a copolymer containing a nitrile radical containing copolymer rubber and acrylic resin particles or a polymer alloy obtained by kneading. Otherwise, the outer layer is formed of a rubber composition which does not contain halogen containing materials including a vinyl chloride resin, such as a rubber composition (a blended material) consisting the nitrile radical containing copolymer rubber and another than the nitrile radical containing copolymer rubber. During blending the rubber composition forming the inner layer, the rubber composition is preferably used which does not contain wax. Preferably, the inner layer has a thickness of 1.0 mm or more. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

TECHNICAL FIELD The present invention relates to, for example, automobile hoses whose internal fluid is fuel (including fuel mixed with oil and vapor gas), such as fuel hoses, vapor hoses, engine control hoses, and vacuum brake hoses. Related to hoses.

Conventionally, acrylonitrile butadiene rubber (NBR) is excellent in oil resistance and fuel oil resistance and is widely used as a hose for automobiles, but is inferior in ozone resistance. Therefore, a hose coated with chlorosulfonated polyethylene (CSM) based on a blend of acrylonitrile butadiene rubber (NBR) and polyvinyl chloride (PVC), which has both oil resistance, fuel oil resistance, and ozone resistance, is a fuel for automobiles. Used for hoses.

However, halogen-containing resins such as vinyl chloride may cause environmental problems such as halogen being liberated during waste treatment, and contain nitrile group-containing copolymer rubber and acrylic resin. A fuel hose using a polymer alloy is disclosed.
JP 2004-91506 A

However, a fuel hose using a polymer alloy containing a nitrile group-containing copolymer rubber and an acrylic resin has the same ozone resistance as a blend material of acrylonitrile butadiene rubber (NBR) and polyvinyl chloride (PVC). However, it is inferior in ozone resistance compared to a hose coated with chlorosulfonated polyethylene (CSM) based on a blend of acrylonitrile butadiene rubber (NBR) and polyvinyl chloride (PVC). Therefore, it has been found that these fuel hoses cannot sufficiently satisfy the maintenance-free requirement.

The present invention has been made in view of the current situation, and aims to provide an automotive hose that does not contain halogen-containing materials such as vinyl chloride resin that cause environmental problems and has sufficient ozone resistance. To do. Another object of the present invention is to provide an automotive hose excellent in oil resistance, fuel oil resistance, and fuel oil permeability.

  The present invention has the following configuration in order to achieve the above object. That is, the automotive hose according to the present invention is an automotive hose comprising two or more layers, and the inner layer is obtained by kneading or kneading a copolymer containing nitrile group-containing copolymer rubber and acrylic resin particles. It is characterized in that it is formed by a rubber composition using the polymer alloy as a polymer. It is preferable to use a rubber composition containing no wax during the blending of the rubber composition. The wall thickness of the inner layer is preferably 1.0 mm or more.

  In order to achieve the above object, an automotive hose according to the present invention is an automotive hose formed by an inner layer serving as an inner layer and an outer layer provided on the outer peripheral surface of the inner layer, and the outer layer is made of a vinyl chloride resin or the like. The rubber composition does not contain any halogen-containing material. The outer layer may be formed of a rubber composition (blend material) made of a material other than nitrile group-containing copolymer rubber and nitrile group-containing copolymer rubber. Further, the inner layer and the outer layer are combined, and the inner layer is formed of a rubber composition using a copolymer containing a nitrile group-containing copolymer rubber and acrylic resin particles or a polymer alloy obtained by kneading as a polymer, It is good also as a structure which forms an outer layer with the rubber composition which does not contain halogen containing materials, such as a vinyl chloride resin. In such a case, the thickness of the inner layer is preferably 1.0 mm or more.

  With the above configuration, an automotive hose excellent in ozone resistance, oil resistance, fuel oil resistance, fuel oil permeability, and the like can be obtained.

  Below, the embodiment of the hose for vehicles concerning this invention is described in detail. As shown in FIG. 1, a hose having a multi-layer structure in which an inner layer 1 serving as an inner layer and an outer layer 3 are provided on the outer side thereof via a reinforcing yarn layer 2, the inner layer 1 is a nitrile group-containing copolymer rubber. And a copolymer containing acrylic resin particles or a polymer alloy obtained by kneading is formed from a rubber composition using as a polymer, and is obtained from the following examples. Various known carbon blacks, plasticizers, vulcanizing agents, vulcanization accelerators, anti-aging agents and the like are added to the rubber composition as necessary. In addition, it is preferable to use a rubber composition that does not contain wax during compounding of the rubber composition. The wall thickness of the inner layer is preferably 1.0 mm or more. This is because when the inner layer has a thickness of 1.0 mm or less, sufficient fuel oil permeability cannot be obtained.

  FIG. 2 is a perspective view in which a part of an automobile hose formed by an inner layer 1a serving as an inner layer and an outer layer 3a provided on the outer peripheral surface of the inner layer is cut away. The outer layer 3a of the automobile hose was formed from a rubber composition not containing a halogen-containing material such as vinyl chloride resin. The outer layer 3a is formed by a rubber composition excellent in ozone resistance formed by a rubber composition (blend material) other than a nitrile group-containing copolymer rubber and a nitrile group-containing copolymer rubber. The wall thickness of the inner layer is preferably 1.0 mm or more. This is because when the inner layer has a thickness of 1.0 mm or less, sufficient fuel oil permeability cannot be obtained.

  Next, various tests were performed on the rubber composition used for the inner layer 1. Example 1 was manufactured by Nippon Zeon Co., Ltd. as a copolymer containing a nitrile group-containing copolymer rubber having high nitrile content (36 to 43%) and acrylic resin particles used for the inner layer or a polymer alloy obtained by kneading. A test piece obtained by vulcanizing a rubber composition appropriately blended with “D2031” of No. 1 was used. On the other hand, in Comparative Example 1, as a blend material of acrylonitrile butadiene rubber (NBR) having an extremely high nitrile content (43% or more) and polyvinyl chloride (PVC), a product name “DN508SCR” manufactured by Nippon Zeon Co., Ltd. is used for the polymer. It was.

  The blend material of acrylonitrile butadiene rubber (NBR) and polyvinyl chloride (PVC) having an extremely high nitrile content (43% or more) used in Comparative Example 1 currently complies with fuel evaporation regulations in Japan and the EU. It is a material commonly used for automobile fuel hoses.

Various test methods are as follows.
<Normal physical properties>
The hardness, tensile strength and elongation were measured according to JIS K 6251 (vulcanized rubber tensile test method) and JIS K 6253 (vulcanized rubber and thermoplastic rubber hardness test method).
<Oil resistance>
In accordance with JIS K 6258 (vulcanized rubber immersion test method), the test piece was immersed in IRM903 and subjected to accelerated aging at 120 ° C. for 70 hours, and then the volume change rate was measured.
<Fuel resistance>
According to JIS K 6258 (vulcanized rubber immersion test method), the test piece was subjected to accelerated aging at room temperature for 70 h in a test solution in which isooctane 40 vol% and toluene 60 vol% were mixed, and the volume change rate was measured.
<Ozone resistance>
In accordance with JIS K 6259 (vulcanized rubber ozone degradation test method), after leaving the test piece 20% extended in an atmosphere with an ozone concentration of 50 pphm at 40 ° C. for 72 hours, check for cracks. did.
<Fuel resistance to fuel oil>
A specific method of fuel oil permeation resistance will be described with reference to FIG. In the test container Y, the lower part of the cap 8 is fitted to a fixing part 7 protruding from the outer periphery of the upper end of the cup 5 via the flange 6, and the upper end flange part 9 of the cap 8 and the fixing part 7 are drilled at an appropriate interval. The bolt 10 is fixed by being screwed into the bolt hole provided and assembled.

  A specific method of using the test container Y is as follows. First, a test liquid (Fuel C) 11 in which 50 vol% of isooctane and 50 vol% of toluene are mixed in a cup 5, and then a packing 12 and a test piece for evaluation are placed on the flange 6. 13 and packing 14 are sequentially placed, and finally the lower end portion of the cap 8 formed by drilling a large number of small holes 16 is fitted inside the fixing portion 7, and the bolt 10 is inserted into the bolt holes drilled at appropriate intervals. Screw together and assemble to completely seal the opening. In this way, the permeability coefficient of the test liquid (Fuel C) 11 permeating through the small hole 16 of the cap 8 was measured. Moreover, about the thing using commercially available regular gasoline for a test liquid, it tested by the same method and measured the permeability coefficient. The measurement results are shown in Table 1.

From the above test results, oil resistance, fuel oil resistance, and ozone resistance were obtained when Example 1 used a copolymer containing a nitrile group-containing copolymer rubber and acrylic resin particles in a polymer or a polymer alloy obtained by kneading. It shows that a vulcanized rubber having excellent properties can be obtained.
In this example, a copolymer containing a nitrile group-containing copolymer rubber having high nitrile content (36 to 43%) and acrylic resin particles or a polymer alloy obtained by kneading was used as a polymer. A copolymer containing a nitrile group-containing copolymer rubber and acrylic resin particles having an extremely high nitrile content (43% or more) and the like, and an acrylic resin particle, or a rubber composition obtained by kneading is used as a polymer. Thus, it is clear that a vulcanized rubber having excellent fuel oil permeability can be obtained.

  Next, the test which changed conditions further about the ozone resistance of material was done. In Example 2, the amount of carbon in Example 1 was reduced and more wax was added. As the wax, 2 phr of “Sannok P” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. was added, and a vulcanized test piece was appropriately blended. In Example 3, a test piece obtained by appropriately blending and vulcanizing a blend material of acrylonitrile butadiene rubber (NBR) and ethylene vinyl acetate copolymer (EVM) as a polymer was used. For the acrylonitrile butadiene rubber (NBR), use the name “Nanker 1041” manufactured by Nantei Chemical Co., and for the ethylene vinyl acetate copolymer (EVM) use the product name “Revaprene 800HV” manufactured by Bayer. A blend of 30 parts of EVM was used as the polymer.

  On the other hand, Comparative Example 2 used a test piece obtained by appropriately mixing and vulcanizing a polymer made of DuPont's trade name “Hypalon # 40” as chlorosulfonated polyethylene (CSM).

The test method is as follows.
<Ozone resistance test>
According to JIS K 6259 (Ozone Degradation Test Method for Vulcanized Rubber), the specimen is left in an atmosphere of ozone concentration of 100 pphm at 40 ° C. with the specimen extended to 80%, and taken out at an arbitrary time to generate cracks. The presence or absence was confirmed.
<Oil resistance>
In accordance with JIS K 6258 (vulcanized rubber immersion test method), the test piece was immersed in IRM903 and subjected to accelerated aging at 120 ° C. for 70 hours, and then the volume change rate was measured.
<Fuel resistance>
According to JIS K 6258 (a vulcanized rubber immersion test method), the test piece was subjected to accelerated aging at room temperature for 70 h in a test solution in which isooctane 40 vol% and toluene 60 vol% were mixed, and then the volume change rate was measured. The measurement results are shown in Table 2.

Example 1 has equivalent ozone resistance as compared with Comparative Example 1, and when it is used as an automobile hose, it can sufficiently withstand ozone attack from the end face of the hose. It is insufficient when considering a use state that is greatly extended by insertion of the other pipe.

  In recent years, maintenance-free is also required for automobile hoses, and when the life of a car is 10 years and 200,000 km and various environments and usage conditions are taken into account, cracks are generated for 50 hours or more in the ozone resistance test. Preferably not. A hose using a polymer alloy containing a nitrile group-containing copolymer rubber and an acrylic resin, which is a conventional technique (see, for example, JP-A-2004-91506) is inferior in ozone resistance compared to Comparative Example 2, It is insufficient.

  Although it is common to add wax as a technique for improving ozone resistance, the inventors have repeated the blending study and in Example 2, by reducing the amount of carbon and adding the wax, the weight loss of the carbon and the wax are reduced. It has been clarified that ozone resistance is drastically improved by the synergistic effect with the addition of.

  In Example 3, a blend material of acrylonitrile butadiene rubber (NBR) and ethylene vinyl acetate copolymer (EVM) is used as a polymer, and a vulcanizate excellent in ozone resistance can be obtained by appropriately blending. Show. When considering only ozone resistance, good ozone resistance can be obtained without using halides such as PVC using EVM or EPDM, but by using a blend material with NBR for the polymer, oil resistance and fuel resistance A material excellent in oiliness can be obtained, and safety can be improved against adhesion of oil, fuel oil, etc. from the outside, which is good.

  In Example 3, a blend material of acrylonitrile butadiene rubber (NBR) and ethylene vinyl acetate copolymer (EVM) was used as a polymer. ), Hydrogenated nitrile rubber (H-NBR) and the like can be blended, and instead of EVM, the material can be appropriately selected and used as a blend with NBR.

  Next, a hose was actually made using the rubber composition obtained in the above-described example, and various tests were performed. The hose had an inner diameter of 6 mm and an outer diameter of 10.5 mm. Examples 4 and 5 were single layers. In Example 4, the rubber composition shown in Example 1 was used for the inner layer, and in Example 5, the rubber composition shown in Example 2 was used. Examples 6 and 7 are multi-layered. Example 6 uses the rubber composition of Example 1 for the inner layer, the rubber composition of Example 2 for the outer layer, and Example 7 for the inner layer. It was prepared using the rubber composition of Example 1 and the rubber composition of Example 3 as the outer layer. On the other hand, Comparative Example 3 was prepared using the rubber composition of Comparative Example 1 for the inner layer and the rubber composition of Comparative Example 2 for the outer layer.

The test method is as follows.
<Extractability test>
A test liquid in which 40 vol% of isooctane and 60 vol% of toluene are mixed in a hose, and left at 23 ± 2 ° C. for 70 hours. The extract is transferred to an eggplant-shaped flask, and the test liquid is removed using an evaporator. Thereafter, the state of the extract remaining in the flask was confirmed.
<Ozone resistance test>
Divide the hose into two parts, and leave it in an atmosphere of 100 pphm ozone concentration at 40 ° C with the hose extended to 80% according to JIS K 6259 (method for ozone deterioration test of vulcanized rubber). Then, it was taken out and checked for occurrence of cracks. The test results are shown in Table 3.

In Example 4, it can be considered that the result of the ozone resistance test cannot sufficiently answer the maintenance-free request. Further, in Example 5, cracks and the like were not observed in the ozone resistance test, and it was considered that the ozone resistance was excellent, but it was confirmed that the extract became a gel in the extractability test.

Hose such as vapor hose, engine control hose, vacuum brake hose, etc. are often used in combination with valves such as 2-way valve, check valve, etc. It is conceivable to fix, and it is not preferable to add wax to the material that is in contact with the fluid, which may cause malfunction.

  In Examples 6 and 7, cracks are observed in the inner layer in the ozone resistance test, but the ozone attack in the actual vehicle use state is from the outer surface, and the inner layer protected by the outer layer is the actual vehicle use state Thus, it is considered that no cracks are generated.

From these results, a copolymer containing a nitrile group-containing copolymer rubber and acrylic resin particles in the inner layer or a polymer alloy obtained by kneading is used for the polymer, and a rubber composition containing no wax is used during compounding. By forming a hose with two or more layers using a rubber composition that does not contain halogen-containing substances such as vinyl chloride resin in the outer layer and is more excellent in ozone resistance than the inner layer, sufficient ozone resistance Therefore, it is possible to obtain a hose excellent in oil resistance, fuel oil resistance, and fuel oil permeability without containing halogen-containing materials such as vinyl chloride resin that cause environmental problems.

Furthermore, using the rubber composition obtained by the said Example, the hose of inner diameter 6mm and outer diameter 10.5mm was created, and various hose performance was evaluated. The evaluation method is as follows.
<Heat aging resistance>
After the sample is aged in accordance with JIS K 6257 (vulcanized rubber aging test method) in a straight state, the sample is allowed to stand at room temperature for 3 hours or more and bent 180 ° to check whether there is any abnormality inside or outside the hose.
<Ozone degradation>
(Outside)
In accordance with method 2 (1) A in Section 6.3 (Ozone degradation test) of JASO M319 (General hose test). However, the ozone deterioration test is conducted under the conditions of ozone concentration 100 ± 5 pphm, temperature 40 ± 2 ° C., 300 ± 2 h, and the outer diameter of the cylinder used is 8 times the outer diameter of the hose. After the deterioration test, observe the appearance of the sample and investigate the occurrence of cracks.
(Joining part)
In accordance with 2 (3) C method in 6.3 (ozone degradation test) of JASO M319 (General Rules for Hose Tests). However, the ozone deterioration test is performed under the conditions of ozone concentration of 100 ± 5 pphm, temperature of 40 ± 2 ° C., and 300 ± 2 h. The test is performed by inserting the same pipe used for the actual vehicle. After the deterioration test, observe the appearance of the sample and investigate the occurrence of cracks.
<Pressure resistance>
(air tightness)
According to 6.1.2 (3) (Airtight test) of JASO M319 (General hose test). However, the pressure is 249 kPa, the holding time is 5 min, local swelling, deformation,
Check for abnormalities such as cracks and cracks.
(Negative pressure)
JASO M319 (General hose test) 6.1.2. Perform (4) (Negative pressure test). However, the decompression force is 13.3 kPa, the holding time is 5 minutes, the decompression speed is 1.3 to 8.0 kPa per second, and the presence or absence of abnormality such as constriction and deformation is observed.
<Vibration fatigue>
A hose with a free length of 150 mm is assembled in a straight line, and vibration is applied to one end. However, the frequency is 1000 cpm, the amplitude is 10 mm, the test temperature is room temperature, and after 250 hours, the presence or absence of harmful defects such as a hose crack is checked.
<Fuel oil permeability>
Measure the fuel evaporation of the hose with the SHED test device. However, the fuel to be used is regular gasoline, and the SHED chamber temperature at the time of measurement depends on EU step 3 and the DOM2000 transpiration regulation temperature profile.

  The test results are shown in Table 4.

The above test results show that the hose obtained by the present invention is a hose in which the internal fluid is fuel (including fuel mixed with oil and vapor gas), for example, fuel hose, vapor hose, engine control hose, vacuum brake hose It shows that it has sufficient performance as an automotive hose.
When used as an automotive fuel hose that complies with fuel transpiration regulations in Japan and the EU, the transpiration rate in the fuel oil permeability test is preferably 0.55 g / m · TEST or less, and the inner layer thickness is 1 A more suitable hose can be obtained by setting it as 0.0 mm or more.

It is the perspective view which notched a part of hose for motor vehicles which has a reinforcing thread layer concerning this invention. It is the perspective view which notched a part of hose for vehicles which consists of two layers concerning this invention. It is sectional drawing and the top view of an apparatus which show the evaluation method of gasoline permeability.

Explanation of symbols

1, 1a Inner layer 2 Reinforcement yarn layer 3, 3a Outer layer

Claims (7)

  A rubber hose comprising two or more layers of an automotive hose, wherein the inner layer is a copolymer containing a nitrile group-containing copolymer rubber and acrylic resin particles, or a polymer alloy obtained by kneading is used as a polymer. Automotive hose formed by   The automotive hose according to claim 1, wherein a rubber composition containing no wax is used during compounding. The automotive hose according to claim 1 or 2, wherein the inner layer has a thickness of 1.0 mm or more.   An automotive hose formed by an inner layer serving as an inner layer and an outer layer provided on the outer peripheral surface of the inner layer, wherein the outer layer is formed of a rubber composition not containing a halogen-containing material such as a vinyl chloride resin.   The automotive hose according to claim 4, wherein the outer layer is formed of a rubber composition (blend material) made of a material other than nitrile group-containing copolymer rubber and nitrile group-containing copolymer rubber.   A rubber hose comprising two or more layers of an automotive hose, wherein the inner layer is a copolymer containing a nitrile group-containing copolymer rubber and acrylic resin particles, or a polymer alloy obtained by kneading is used as a polymer. A hose for automobiles formed by a rubber composition that does not contain a halogen-containing material such as a vinyl chloride resin.   The automotive hose according to claim 6, wherein the inner layer has a thickness of 1.0 mm or more.

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