JP2008114452A - Fuel hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel hose having excellent interlayer adhesiveness and flexibility and also being excellent in the low permeability for fuels. <P>SOLUTION: The hose has an innermost layer 1 composed of one or more selected from acrylonitrile-butadiene rubbers (NBR), blend rubbers (NBR/PVC) consisting of an acrylonitrile-butadiene rubber and a polyvinyl chloride, polychloroprene rubbers (CR), epichlorohydrin rubbers (ECO), chlorosulfonated polyethylenes (CSM), fluoro-rubbers (FKM), chlorinated polyethylene rubbers (CPE), polyether sulfone (PES) and fluoro-resins; a low-permeability layer 2 arranged on the outer periphery of the innermost layer 1; and a rubber outer layer arranged on the outer periphery of the low-permeability layer 2 and consisting of an inner-surface rubber outer layer 3a and outer-surface rubber outer layer 3b. The low-permeability layer 2 is composed of a resin film based on a polyvinyl alcohol of a degree of saponification of ≥90%, and the resin film has a thickness of 2-100 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel hose, and more particularly, gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, light oil, dimethyl ether, diesel, CNG (compressed natural gas), LPG (liquefied) used in automobiles and the like. The present invention relates to a fuel hose used for transportation of fuel such as petroleum gas.

Due to increasing global environmental awareness, regulations on the evaporation of hydrocarbons from fuel hoses, especially automobile fuel hoses, have been tightened, and in particular, strict transpiration regulations have been legislated in the United States. Under such circumstances, in order to comply with the regulation of the transpiration of hydrocarbons, fluorine-based resins such as ethylene-tetrafluoroethylene copolymer (ETFE), polyamide 11, polybutylene terephthalate (PBT), ethylene-vinyl alcohol A multi-layered hose having a low fuel permeation layer made of a copolymer (EVOH) or the like has been proposed (see Patent Document 1).
JP 2005-212481 A

  However, a hose provided with a layer made of ETFE, EVOH or the like has a tendency to be inferior in interlayer adhesion because of poor adhesion to other materials. In addition, when responding to the regulation of hydrocarbon transpiration by only the ETFE layer, EVOH layer, etc., the thickness of the layer must be increased, resulting in flexibility, ease of assembly, vibration transmission suppression, etc. Problems may arise.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a fuel hose that is excellent in interlayer adhesion, flexibility and the like and excellent in low permeability to fuel.

  In order to achieve the above object, the fuel hose of the present invention comprises an acrylonitrile-butadiene rubber (NBR), a blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride (NBR / PVC), a chloroprene rubber (CR), an epithelium. At least one selected from the group consisting of chlorohydrin rubber (ECO), chlorosulfonated polyethylene (CSM), fluorine rubber (FKM), chlorinated polyethylene rubber (CPE), polyethersulfone (PES), and fluorine resin. A hose comprising an innermost layer formed using, a low-permeability layer provided on the outer periphery of the innermost layer, and a rubber outer layer provided on the outer periphery of the low-permeability layer, wherein the low-permeability layer has a degree of saponification It is formed of a resin film mainly composed of 90% or more polyvinyl alcohol, and the thickness of the resin film is A configuration that is set in the range of ～100Myuemu.

  That is, the present inventors have intensively studied to solve the above problems. In the process, if the innermost layer of the hose is formed using rubber such as NBR, NBR / PVC, CR, ECO, CSM, FKM, CPE, or resin such as PES, fluororesin, the oil resistance against the fuel flowing through the hose is increased. In addition, when a coating film was formed on the outer periphery of the innermost layer using polyvinyl alcohol having a saponification degree of 90% or higher, the interlayer adhesion with the innermost layer was excellent, and the coating film was a thin film. However, it has been found that it has excellent low permeability to hydrocarbons. And, by setting the thickness of the coating film within a specific range, the balance between the low permeability and the flexibility of the hose is good, and further by providing a rubber outer layer on the outer periphery of the coating film, Since it becomes excellent in the absorptivity and the hose resistance with respect to the mechanical impact from the outside, etc., it has been found that the desired hose performance can be exhibited by such a configuration, and the present invention has been achieved.

  As described above, the fuel hose of the present invention is the innermost layer formed by using NBR, NBR / PVC, CR, ECO, CSM, FKM, CPE, PES, and fluororesin alone or in combination of two or more. And a low-permeability layer provided on the outer periphery of the innermost layer, and a rubber outer layer provided on the outer periphery of the low-permeability layer, wherein the low-permeability layer is mainly composed of polyvinyl alcohol having a saponification degree of 90% or more. Formed by a resin film that has a thickness of 2 to 100 μm, so that it is possible to obtain particularly low permeation performance for hydrocarbons, and fuel that has been strengthened in recent years It is possible to comply with the regulation of transpiration of hydrocarbon hoses. Moreover, the fuel hose of the present invention is excellent in fuel oil resistance, excellent in interlayer adhesion and flexibility, advantageous for piping, and as a hose for piping in the engine room of a car with severe vibration. Can also be used advantageously.

  Next, embodiments of the present invention will be described in detail.

  For example, as shown in FIG. 1, the fuel hose of the present invention includes an innermost layer 1, a low-permeability layer 2 provided on the outer periphery of the innermost layer 1, and a rubber outer layer (inner surface) provided on the outer periphery of the low-permeability layer 2. A rubber outer layer 3a and an outer rubber outer layer 3b), the innermost layer 1 is formed of a specific material, and the low-permeability layer 2 is mainly composed of polyvinyl alcohol having a saponification degree of 90% or more. The resin film is formed and the thickness of the resin film is set in the range of 2 to 100 μm. In FIG. 1, the rubber outer layer has a two-layer structure of an inner rubber outer layer 3a and an outer rubber outer layer 3b. However, there is no particular limitation, and there may be a single layer or three or more layers. Good. Moreover, as shown in FIG. 1, you may provide the reinforcement layer 4 suitably.

  As the forming material of the innermost layer 1, acrylonitrile-butadiene rubber (NBR), blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride (NBR / PVC), chloroprene rubber (CR), epichlorohydrin rubber (ECO), At least one selected from the group consisting of chlorosulfonated polyethylene (CSM), fluororubber (FKM), chlorinated polyethylene rubber (CPE), polyethersulfone (PES), and fluororesin is used. Or two or more types are used together. Of these, NBR, NBR / PVC, FKM, PES, and fluororesin are preferably used because they are more excellent in hydrocarbon properties.

  The innermost layer 1 may be formed of carbon black, an antioxidant, a vulcanizing agent, a vulcanization accelerator, a processing aid, a white filler, a plasticizer, a softening agent, an acid acceptor, if necessary. In addition, a coloring agent, a scorch inhibitor and the like can be appropriately blended.

  As described above, polyvinyl alcohol (PVOH) having a saponification degree of 90% or more is used as a material for forming the low-permeability layer 2 formed on the outer periphery of the innermost layer 1. That is, when the polyvinyl alcohol has a saponification degree of less than 90%, a desired level of low permeation performance cannot be obtained particularly for hydrocarbons. Here, the saponification degree of polyvinyl alcohol can be determined by applying the values of m and n to the following formula (a) when the polyvinyl alcohol is represented by the following chemical formula (1).

  Here, in the present invention, “main component” means a component that occupies a majority of the entire resin film, and includes the case where the entirety consists of only the main component.

  Then, PVOH, which is a material for forming the low-permeability layer 2, is used as a coating liquid by dissolving it in water or alcohol (methanol, ethanol, isopropyl alcohol, etc.). In particular, water (hot water of about 90 to 95 ° C.) is preferably used as a solvent from the viewpoint of solubility in the material for forming the low-permeability layer 2. The coating liquid thus obtained preferably has a viscosity of 10 to 1,000,000 (mPa · s / 25 ° C.) in view of coating properties (wetting properties and workability).

  A material for forming the outer rubber outer layer (the inner rubber outer layer 3a and the outer rubber outer layer 3b) on the outer periphery of the low-permeability layer 2 is not particularly limited. For example, butyl rubber (IIR), chlorinated butyl rubber (Cl-IIR), bromine Halogenated butyl rubber such as butylated rubber (Br-IIR), acrylonitrile-butadiene rubber (NBR), NBR / PVC, chloroprene rubber (CR), ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPM), fluorine rubber (FKM), epichlorohydrin rubber (ECO), acrylic rubber, silicon rubber, chlorinated polyethylene rubber (CPE), urethane rubber and the like are used. Of these, NBR, NBR / PVC, CR, FKM, and ECO are preferably used because they are more excellent in hydrocarbon properties. In addition, in the material of the rubber outer layer, if necessary, carbon black, anti-aging agent, vulcanizing agent, vulcanization accelerator, processing aid, white filler, plasticizer, softener, acid acceptor, A coloring agent, a scorch prevention agent, etc. are mix | blended suitably.

  In FIG. 1, the rubber outer layer is composed of two layers, that is, the inner rubber outer layer 3a and the outer rubber outer layer 3b. When the rubber outer layer is composed of two or more layers as described above, the forming material of each layer is the same. Or different. Moreover, you may form the reinforcement layer 4 as needed like FIG. As shown in the figure, the reinforcing layer 4 is preferably interposed between the inner rubber outer layer 3a and the outer rubber outer layer 3b because the function (hose pressure resistance) is sufficiently exhibited. The reinforcing layer 4 is made of, for example, reinforcing yarn such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aramid, polyamide (nylon), vinylon, rayon, metal wire, etc. by spiral braid, knit braid, blade braid, etc. It can be configured as a reinforcing layer by braiding.

  Here, the fuel hose of the present invention as shown in FIG. 1 can be produced, for example, as follows. That is, first, the innermost layer 1 material and the low-permeability layer 2 material (coating liquid) described above are prepared. Next, the innermost layer 1 material is extruded into a hose shape to form a tubular innermost layer 1. At this time, a mandrel may be used. Next, the coating liquid for the low transmission layer 2 is applied to the outer peripheral surface of the innermost layer 1. This coating method is not particularly limited, and conventional methods such as a dipping method, a spray method, a roll coating method, and a brush coating can be applied. And the low permeable layer (resin film | membrane) 2 which has specific thickness is formed by performing a drying process after coating. After forming the low-permeability layer 2 in this way, a rubber outer layer is extruded on the outer periphery of the low-permeability layer 2, and a reinforcing layer 4 is formed as necessary (in FIG. 1, the inner rubber outer layer 3a). After that, the reinforcing layer 4 is formed on the outer peripheral surface thereof, and the outer rubber outer layer 3b is formed on the outer peripheral surface of the reinforcing layer 4), so that a fuel hose having a desired layer structure is manufactured. be able to.

  Before forming the low transmission layer 2, the outer peripheral surface of the innermost layer 1 may be subjected to an etching process such as an ultraviolet irradiation process, a plasma process, or a corona discharge process as an adhesive base process. Among these, the outer peripheral surface of the innermost layer 1 is roughened by plasma treatment in that the coating film adhesion (interlayer adhesion) is improved, and the low transmission layer 2 is directly formed on the rough surface. preferable.

  In addition, an adhesive layer may be formed on the outer peripheral surface of the innermost layer 1 before forming the low transmission layer 2. The material for the adhesive layer is not particularly limited, and examples thereof include phenol-based, silane-based, chlorine-based, urethane-based, polyester-based, isocyanate-based, and epoxy-based adhesives. These may be used alone or in combination of two or more. Especially, since it is excellent in the interlayer adhesiveness of the said innermost layer 1 and the low permeable layer 2, a phenol type adhesive agent is used suitably.

  In the fuel hose of the present invention, the inner diameter of the hose is preferably in the range of 2 to 40 mm. The innermost layer 1 preferably has a thickness in the range of 0.02 to 2.0 mm.

  And in this invention, it is required to make the thickness of the said low permeable layer 2 into the range of 2-100 micrometers. That is, if the thickness of the low-permeability layer 2 is less than 2 μm, it is inferior in low permeability to hydrocarbons. Conversely, if the thickness of the low-permeability layer 2 exceeds 100 μm, the coating film becomes hard, This is because it hinders the flexibility of the hose and may cause cracks.

  Further, the thickness of the outer rubber layer formed on the outer periphery of the low-permeability layer 2 is not particularly limited. However, as shown in FIG. 1, when the outer rubber layer is composed of two layers of the inner rubber outer layer 3a and the outer rubber outer layer 3b, The inner rubber outer layer 3a preferably has a thickness in the range of 0.5 to 5 mm, and the outer rubber outer layer 3b has a thickness in the range of 0.5 to 2.0 mm.

  The fuel hose of the present invention is suitably used for fuel transportation hoses such as gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, light oil, dimethyl ether, diesel, CNG (compressed natural gas), LPG (liquefied petroleum gas), etc. It is done. The fuel transport hose is used in automobiles and transport equipment (industrial transport vehicles such as airplanes, forklifts, excavators, and cranes, railway vehicles, and the like).

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

  NBR was extruded into a hose shape on a mandrel (outer diameter 6 mm) made of TPX (synthetic resin) to form a tubular innermost layer (thickness 0.7 mm). Next, an adhesive layer (thickness 1 μm) made of a phenol-based adhesive is formed on the outer peripheral surface of the innermost layer, and from that, polyvinyl alcohol (PVOH) having a saponification degree of 99% (manufactured by Nippon Synthetic Chemical Co., Ltd., Gohsenol) A coating solution (viscosity: 500 mPa · s / 25 ° C.) obtained by dissolving N-300) in 90 ° C. hot water was dipped. Thereafter, the laminated hose body was placed in a drying furnace and dried to form a coating layer (low transmission layer, thickness 10 μm) by the dipping. Then, after forming an inner rubber outer layer (thickness: 1.0 mm) by extrusion molding of NBR on the outer periphery of the coating layer, a reinforcing layer is formed on the outer peripheral surface by a braid of PET yarn, and further the reinforcing layer An outer rubber outer layer was formed by extrusion molding of ECO on the outer peripheral surface (thickness 1.2 mm). Then, after vulcanization, a mandrel was extracted from the laminated hose body, and a long molded product was cut to produce a target fuel hose (see FIG. 1).

  The thickness of the coating layer (PVOH layer) was formed to 100 μm. Other than that was carried out similarly to Example 1, and produced the target fuel hose.

  The thickness of the coating layer (PVOH layer) was 2 μm. Other than that was carried out similarly to Example 1, and produced the target fuel hose.

  As PVOH for forming the coating layer (PVOH layer), PVOH having a saponification degree of 90% (manufactured by Nippon Synthetic Chemical Co., Ltd., Gohsenol AH-17) was used. And the thickness of the said coating-film layer (PVOH layer) was formed in 2 micrometers. Other than that was carried out similarly to Example 1, and produced the target fuel hose.

[Comparative Example 1]
As PVOH for forming the coating layer (PVOH layer), PVOH having a saponification degree of 86% (manufactured by Nippon Synthetic Chemical Co., Ltd., Gohsenol GH-17) was used. And the thickness of the said coating-film layer (PVOH layer) was formed in 2 micrometers. Other than that was carried out similarly to Example 1, and produced the target fuel hose.

[Comparative Example 2]
The thickness of the coating layer (PVOH layer) was formed to 101 μm. Other than that was carried out similarly to Example 1, and produced the target fuel hose.

[Comparative Example 3]
The thickness of the coating layer (PVOH layer) was 1 μm. Other than that was carried out similarly to Example 1, and produced the target fuel hose.

[Comparative Example 4]
The coating layer (PVOH layer) was not formed, and the others were the same as in Example 1, and a target fuel hose was produced.

  For the hoses of Examples 1 to 4 and Comparative Examples 1 to 4 thus obtained, gasoline permeability and crackability were evaluated according to the following criteria. The results are also shown in Table 1 below.

[Gasoline permeability]
A simulated gasoline mixed with toluene / isooctane / ethanol in a ratio of 45:45:10 (volume ratio) was enclosed in a hose, and the permeability coefficient of the simulated gasoline was measured from the weight change of the enclosed hose at 40 ° C. for 2 weeks. (Unit: mg / m / day). In addition, the value described in the table is a value when equilibrium is reached. Further, in the above measurement method, 0.1 mg / m / day is the measurement limit, and therefore, what was less than 0.1 mg / m / day was described as “<0.1”. And what the said measured value was less than 0.1 mg / m / day was evaluated as (circle), and what was 0.1 mg / m / day or more was evaluated as x.

[Crack property]
In Examples and Comparative Examples, the cracking property of the tube before forming the inner rubber outer layer, the reinforcing layer, and the outer rubber outer layer (the tube having the coating layer (PVOH layer) formed on the outer periphery of the innermost layer and dried) Was evaluated. That is, the tube was bent at 90 °, and the coating layer (PVOH layer) in which an abnormality such as cracking or peeling was confirmed was evaluated as x, and the case in which such an abnormality was not confirmed was evaluated as ◯.

  From the above results, it can be seen that the products of all the examples are more flexible than the products of the comparative examples, so that cracks hardly occur and the gasoline permeation amount can be remarkably reduced.

  The fuel hose of the present invention is used for automobiles and the like, and transports fuel such as gasoline, alcohol-mixed gasoline (gasohol), alcohol, hydrogen, light oil, dimethyl ether, diesel, CNG (compressed natural gas), LPG (liquefied petroleum gas), etc. It can be used suitably for the hose for use.

It is sectional drawing which shows an example of the hose for fuels of this invention.

Explanation of symbols

1 innermost layer 2 low transmission layer 3a inner rubber outer layer 3b outer rubber outer layer

Claims (4)

  Acrylonitrile-butadiene rubber (NBR), blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride (NBR / PVC), chloroprene rubber (CR), epichlorohydrin rubber (ECO), chlorosulfonated polyethylene (CSM), fluorine rubber (FKM), chlorinated polyethylene rubber (CPE), polyethersulfone (PES), and an innermost layer formed using at least one selected from the group consisting of fluororesin, and provided on the outer periphery of the innermost layer. A hose comprising a low-permeability layer and a rubber outer layer provided on the outer periphery of the low-permeability layer, wherein the low-permeability layer is formed of a resin film mainly composed of polyvinyl alcohol having a saponification degree of 90% or more, The thickness of the resin film is set in a range of 2 to 100 μm. A postal hose.   The fuel hose according to claim 1, wherein an adhesive layer is provided between the innermost layer and the low-permeability layer.   The fuel hose according to claim 2, wherein the adhesive layer is formed using a phenol-based adhesive.   The fuel hose according to any one of claims 1 to 3, wherein an outer peripheral surface of the innermost layer is roughened by plasma treatment.

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