JP2007175929A - Fuel hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel hose excellent in flexibility and also excellent in low permeability with respect to fuel. <P>SOLUTION: The outer peripheral surface of a tubular inner layer 1 comprising a rubber or resin is appropriately roughened by plasma treatment and a gas low-permeable layer 2 comprising a resin coating film, which uses at least one of polyacrylic acid and polymethacrylic acid, is formed to the roughened outer peripheral surface of the tubular inner layer 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

Due to the growing global environmental awareness, regulations on fuel permeation from fuel hoses used in automobiles and the like have been strengthened, and in particular, in North America, fairly strict regulations are becoming legislated. In this regard, for example, metal piping is useful because it can completely block the permeation of fuel. However, since metal piping is expensive, heavy, and hard, it has difficulty in assembling, and has problems such as metal fatigue and corrosion when used for a long time. For this reason, rubber or resin hoses are generally used, and this hose is imparted with permeation resistance to fuel. As such a hose having high permeation resistance, for example, a hose having a multilayer structure including a low-permeability resin layer such as ethylene-vinyl alcohol copolymer (EVOH) has already been proposed (see Patent Document 1).
JP 2002-181253 A

  However, a hose provided with a low-permeability resin layer such as EVOH tends to be inferior in flexibility. On the other hand, when a material excellent in flexibility is used, there is a high tendency to be inferior in low fuel permeability, so that it is required to improve this problem.

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

  In order to achieve the above object, a fuel hose according to the present invention is a fuel hose comprising a plurality of constituent layers formed of at least one of rubber and resin, and at least one of the constituent layers is at least one layer. In addition, a low transmission layer composed of a resin coating film using at least one of polyacrylic acid and polymethacrylic acid is employed.

  That is, the present inventor has intensively studied to solve the above problems. In the process, a coating film was formed on the outer periphery of the hose in which the rubber layer and the resin layer were laminated using at least one of polyacrylic acid and polymethacrylic acid. I found out that it became excellent in low permeability. And if the said coating film was a thin film, since it did not interfere with the softness | flexibility of a hose, it discovered that the intended objective could be achieved and reached | attained this invention.

  As described above, the fuel hose of the present invention is excellent in flexibility because the low-permeability layer is a resin coating layer formed using at least one of polyacrylic acid and polymethacrylic acid. Excellent low permeation performance can be obtained for fuel.

  Further, when the thickness of the low transmission layer is set in the range of 1 to 100 μm, the balance between flexibility and low transmission is further improved.

  Further, when the layer in contact with the inner peripheral surface of the low-permeability layer is roughened by plasma treatment, and the low-permeability layer is directly formed on the rough surface, the wettability and adhesiveness between the layers (coating) Film adhesion) is further improved.

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

  For example, as shown in FIG. 1, the fuel hose according to the present invention is formed by forming a low-permeability layer 2 excellent in low permeability for fuel such as an automobile on the outer peripheral surface of a tubular inner layer 1. . In the present invention, the most characteristic feature is that the low transmission layer 2 is a resin coating film formed using at least one of polyacrylic acid and polymethacrylic acid.

  The material for forming the inner layer 1 is not particularly limited. For example, polyester resin such as polyamide resin (PA) and polyethylene terephthalate (PET), fluorine resin, polyolefin resin (polypropylene resin, polyethylene resin, polybutene resin). , Polymethylpentene resin, etc.), acrylic rubber (ACM), fluorine rubber (FKM), acrylonitrile-butadiene rubber (NBR), hydrogenated nitrile rubber (H-NBR), blend of acrylonitrile-butadiene rubber and polyvinyl chloride Rubber (NBR-PVC), hydrin rubber, polyester thermoplastic elastomer (TPEE), butyl rubber (IIR), chlorinated butyl rubber (Cl-IIR), brominated butyl rubber (Br-IIR), ethylene propylene rubber (EPM), ethylene Propylene diene rubber (EPDM) or the like is used. These may be used alone or in combination of two or more. In addition, carbon black, a lubricant (such as stearic acid), zinc oxide, a softening agent (such as process oil), a vulcanizing agent (such as sulfur), and a vulcanization accelerator may be included in the material for forming the inner layer 1 as necessary. Further, a vulcanization aid, an antiaging agent, etc. may be blended appropriately.

  As described above, at least one of polyacrylic acid and polymethacrylic acid is used as a material for forming the low transmission layer 2 formed on the outer peripheral surface of the inner layer 1. Therefore, these polyacrylic acid or polymethacrylic acid may be used alone or in combination. The above does not include modified products.

  Moreover, you may mix | blend hardening | curing agents, such as an isocyanate type, a polyester type, a polyurethane type, a phenol type, a resorcinol type, with the formation material of the said low-permeability layer 2, as needed. Thereby, the crystallinity degree and polymerization degree of a coating film (low-permeability layer 2) can be raised, and film | membrane intensity | strength, low permeability, and coating-film adhesiveness (interlayer adhesiveness) can be improved more.

  In addition to the above components, other additives such as a crosslinking agent, a filler, and an anti-aging agent can be appropriately blended with the material for forming the low-permeability layer 2 as necessary.

  The material for forming the low-permeability layer 2 is used as a coating solution by dissolving in water or alcohol. Examples of the solvent include methanol, ethanol, isopropyl alcohol, pure water and the like. These may be used alone or in combination of two or more. In particular, it is preferable to use water 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 40 to 200,000 (mPa · s / 25 ° C.) in terms of coating properties (wetting properties and workability). The viscosity is more preferably in the range of 45 to 30000 (mPa · s / 25 ° C.).

  Here, the fuel hose of the present invention as shown in FIG. 1 is not particularly limited, but can be produced, for example, as follows. That is, the material for the inner layer 1 and the material for the low permeability layer 2 (coating liquid) described above are prepared. Next, the inner layer 1 material is extruded into a hose shape to form a tubular inner layer 1. At this time, a mandrel may be used. Next, the coating liquid for the low-permeability layer 2 is applied to the surface of the inner 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 2 is formed by performing heat processing (100-180 degreeC * 3-60 minutes) after coating. In this way, a fuel hose having a two-layer structure as shown in FIG. 1 can be produced.

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

  In the fuel hose of the present invention, the inner diameter of the hose is preferably in the range of 2 to 40 mm, particularly preferably in the range of 2.5 to 36 mm. Further, the thickness of the inner layer 1 is preferably in the range of 0.02 to 2.0 mm, particularly preferably in the range of 0.05 to 1.5 mm.

  The thickness of the low transmission layer 2 is preferably in the range of 1 to 100 μm. Especially preferably, it exists in the range of 2-50 micrometers. That is, if the thickness of the low transmission layer 2 is less than 1 μm, pinholes may occur. Conversely, if the thickness of the low transmission layer 2 exceeds 100 μm, the coating film may become hard and crack. Because there is.

  Note that the fuel hose of the present invention is not limited to the two-layer structure as shown in FIG. 1. For example, the inner layer 1 is formed of a plurality of layers including a resin layer and a rubber layer. Alternatively, a multilayer structure of three or more layers may be used. Moreover, although it is preferable to form the said low permeable layer 2 as an outermost layer of a hose as shown in FIG. 1, it is not limited to this, For example, it can also form as an intermediate | middle layer and an inner layer. Further, if necessary, reinforcing yarns may be interposed between these layers.

  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.

  PA11 (manufactured by Arkema, Rilsan BESN P20) was extruded on a mandrel (outer diameter: 24 mm) made of TPX (synthetic resin) into a hose shape to form a tubular inner layer (thickness 0.15 mm). Next, a plasma treatment was performed on the outer peripheral surface of the inner layer to roughen the outer peripheral surface of the inner layer. Subsequently, a coating solution (viscosity: 100 mPa · s / 25 ° C.) obtained by dissolving polyacrylic acid (manufactured by Nippon Pure Chemical Co., Ltd., Jurimer AC-10P) in water was dipped on the surface of the roughened inner layer. . Thereafter, a heat treatment was performed at 100 ° C. for 20 minutes to form a coating layer (thickness 10 μm), and a fuel hose (inner diameter 24 mm) having a two-layer structure was produced.

  As a coating solution for dipping on the surface of the inner layer made of PA11, a coating solution (viscosity: 100 mPa · s / 25 ° C.) obtained by dissolving polymethacrylic acid (manufactured by Nippon Pure Chemical Co., Ltd., Jurimer AC-30H) in water was used. . Other than that was carried out similarly to Example 1, and produced the fuel hose (inner diameter 24mm) of a two-layer structure.

[Comparative Example 1]
A PA11 hose having a single layer structure was produced in the same manner as in Example 1 except that plasma treatment and coating were not performed.

[Comparative Example 2]
EVOH (Kuraray Co., Eval F101) is extruded on a mandrel (outer diameter: 24 mm) made of TPX (synthetic resin) in a hose shape (thickness: 0.15 mm), then removed from the mandrel, and EVOH having a single layer structure A hose was made.

  Using the hoses of Examples 1 and 2 and Comparative Examples 1 and 2 thus obtained, the flexibility and gasoline permeability were measured and evaluated according to the following criteria. The results are also shown in Table 1 below.

[Flexibility]
The hose flexural modulus (MPa) at 25 ° C. was measured according to ASTM D790.

[Gasoline permeability]
Each fuel hose of the example and comparative example was cut open in the longitudinal direction, and then punched into a disk shape to prepare a sample sheet. And the opening part of the cup which enclosed gasoline (Fuel C, toluene: ethanol = 50 volume%: 50 volume%) was closed with the sample sheet | seat, and this was left to stand in 40 degreeC oven. Then, the gasoline weight loss in the cup was plotted with time, and the gasoline permeation amount per day (gasoline permeation coefficient, mg · mm / cm ² · day) with respect to the permeation area of the sample sheet was calculated based on the slope.

  From the above results, it is not possible to detect gasoline permeation in all the example products provided with the coating layer, and the example products show a bending elastic modulus of about 1/10 of that of the EVOH hose of Comparative Example 2. It was excellent in flexibility.

  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 Inner layer 2 Low transmission layer

Claims (4)

  A fuel hose provided with a plurality of constituent layers formed of at least one of rubber and resin, wherein at least one of the constituent layers includes at least one of polyacrylic acid and polymethacrylic acid A fuel hose characterized by being a low-permeability layer comprising:   The fuel hose according to claim 1, wherein the thickness of the low-permeability layer is set in a range of 1 to 100 μm.   The fuel hose according to claim 1 or 2, wherein a layer in contact with the inner peripheral surface of the low-permeability layer is roughened by plasma treatment, and the low-permeability layer is directly formed on the rough surface.   The fuel hose according to any one of claims 1 to 3, which is a hose for automobile fuel transportation.

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