JP2005082004A - Resin-made tube for automobile piping - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin-made tube for automobile piping of high heat resistance, chemical resistance and a water resisting property which is used as a vapor fuel pipe assembled in a metallic fuel tank or the like. <P>SOLUTION: In the resin-tube press-fitted to and mounted on a pipe connection part of an automobile, the resin-made tube 10 for automobile piping comprises a tube body 20 mainly composed of 6,6-nylon, and a protective layer 30 mainly composed of 11-nylon and/or 12-nylon which covers at least the outer periphery of a portion 21 press-fitted into the pipe connection part 50 of the tube body. The protective layer 30 may be extruded simultaneously with the tube body so as to cover the overall length of the tube body 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resin tube for automobile piping suitable for various automobile piping, particularly fuel vapor piping disposed in a metal fuel tank.

  Various pipes are provided in automobiles, and some of them are made of resin tubes. Resin tubes have the advantage that they are lighter and easier to handle than metal tubes and rubber tubes, and can be connected with one touch by using a resin connector or the like. Also, the manufacturing cost tends to be lower than that of metal tubes and rubber tubes.

  Conventionally, 11-nylon, 12-nylon, and the like have been used as resin tubes for automobile piping. These materials have the advantage that they are highly flexible and give freedom to the pipe shape.

  However, for example, in a fuel vapor pipe incorporated in a metal fuel tank, it is exposed to a high temperature atmosphere of about 160 ° C. in the tank painting and drying process after being piped in the tank. The resin tube made of 12-nylon has a problem of thermal deformation.

  Further, not only fuel vapor pipes but also resin tubes disposed in, for example, an engine room are often exposed to high temperatures. Therefore, resin tubes made of 11-nylon or 12-nylon have sufficient heat resistance. In some cases, properties and strength could not be obtained.

  Furthermore, as a resin tube for automobile piping, in addition to heat resistance and strength, for example, fuel resistance is required for fuel piping, and oil resistance is required for oil piping. Furthermore, chemical resistance and water absorption resistance against calcium chloride sprayed as an antifreezing agent for roads, acids and amines generated in the fuel tank are also required.

  On the other hand, Patent Document 1 below discloses a resin tube for automobile piping, which is formed of a resin composition containing 6,6-nylon, 6-nylon, and a plasticizer in a predetermined ratio. Has been.

Further, in Patent Document 2 below, in a resin hose with a protector in which a protector molded with an elastomer material is attached to a hose body molded with a polyamide-based resin, the protector uses the thermoplastic elastomer material to form the hose. A protector-equipped resin fuel hose is disclosed that is molded in close contact with a main body.
JP 2003-49976 A Japanese Patent Laid-Open No. 11-294645

  As described above, a resin tube made of 11-nylon or 12-nylon has insufficient heat resistance, and thus cannot be used as, for example, a fuel vapor pipe incorporated in a metal fuel tank.

  On the other hand, 6,6-nylon is known as a heat-resistant resin material. However, 6,6-nylon does not have sufficient chemical resistance and water absorption resistance, and 11-nylon and 12-nylon. There was a tendency to be hard and fragile.

  In addition, the resin tubes described in Patent Document 1 and Patent Document 2 are also used as, for example, a fuel vapor pipe incorporated in a metal fuel tank, for example, heat resistance, chemical resistance, water absorption resistance. Was not enough.

  Accordingly, an object of the present invention is to provide a resin tube for automobile piping that has high heat resistance, chemical resistance, and water absorption resistance and can be used as, for example, a fuel vapor piping incorporated in a metal fuel tank. .

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a resin tube that is press-fitted and attached to the outer periphery of a pipe connection part of an automobile. Provided is a resin tube for automobile piping, characterized by comprising a protective layer mainly formed of 11-nylon and / or 12-nylon, which covers at least the outer periphery of the portion press-fitted into the piping connection portion. is there.

  According to the said invention, since the tube main body is mainly formed with 6, 6 nylon, heat resistance improves. Further, since a protective layer made of 11-nylon and / or 12-nylon is provided on the outer periphery of the press-fitting portion to the piping connection portion of the automobile, the protective layer provides chemical resistance and water absorption resistance. Improves the shortcoming of 6,6-nylon which is hard and brittle. Furthermore, polyamide resins such as nylon are excellent in fuel resistance and oil resistance. As a result, sufficient heat resistance and durability are obtained even when used in fuel vapor piping that is pre-installed in a metal fuel tank and exposed to a high-temperature atmosphere of about 160 ° C during tank painting and drying processes. Can be granted.

  According to a second aspect of the present invention, in the first aspect of the present invention, the protective layer provides a resin tube for automobile piping that is extruded simultaneously with the tube main body so as to cover the entire length of the tube main body. It is.

  According to the above invention, since the protective layer is formed over the entire length of the tube main body, the chemical resistance and the water absorption resistance are further improved, and the physical properties are further improved.

  According to the present invention, it is possible to provide a resin tube having high heat resistance, chemical resistance, and water absorption resistance. This resin tube is provided in, for example, a fuel vapor pipe incorporated in a metal fuel tank or an engine room. It can also be used as a fuel tube, an oil tube or the like.

  1 to 3 show a first embodiment of a resin tube for automobile piping according to the present invention. 1 is a partial cross-sectional view showing a state in which the resin tube is press-fitted into a pipe connection portion, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 3 is a cross-sectional view of the resin tube in a metal fuel tank. It is explanatory drawing which shows the state applied to the fuel vapor | steam piping built in.

  The resin tube 10 includes a tube main body 20 and a protective layer 30 that covers the outer periphery of the press-fit portion 21 that is press-fitted into the pipe connection portion 50 of the tube main body 20. The pipe connection portion 50 is provided, for example, in the connector 60 in FIG. 3, and a plurality of annular protrusions 51 are formed on the outer periphery thereof at a predetermined interval. The annular protrusion 51 has a tapered surface on the tube receiving side. The resin tube 10 is press-fitted into the outer periphery of the pipe connection portion 50, hermetically sealed by the annular protrusion 51, and prevented from coming off. In the present invention, the pipe connection part means, for example, a pipe connection port provided in a fuel tank, an engine, or the like, a tube connection part of a connector for connecting to the pipe connection port, or the like.

  In this embodiment, the tube main body 20 is formed of a resin composition mainly composed of 6,6-nylon. Since 6,6-nylon is poor in flexibility, it is preferable to add a plasticizer. As the plasticizer, for example, one or more compounds selected from sulfonamide derivatives, sulfonic acid ester derivatives, phosphoric acid ester derivatives, phosphazene derivatives, carboxylic acid amide derivatives, and carboxylic acid ester derivatives are preferably used. The addition amount of the plasticizer is preferably 3 to 20 parts by mass, more preferably 5 to 10 parts by mass. The tube body 20 may be mainly composed of 6,6-nylon, and may be composed of 6,6-nylon alone or a mixture of 6,6-nylon and other resins. For example, a mixture of 6,6-nylon and 6-nylon may be used. Further, it may be a multilayer tube composed of a layer made of 6,6-nylon and a layer made of another resin.

  The protective layer 30 is formed of a resin composition mainly composed of 11-nylon and / or 12-nylon. The resin composition may be a single layer made of 11-nylon or 12-nylon, or may be a single layer made of a mixture of 11-nylon and 12-nylon, and the 11-nylon layer and the 12-nylon layer are polymerized. It may be composed of multiple layers. Furthermore, a layer of another material such as an olefin-based elastomer may be polymerized on the layer of the resin composition mainly composed of 11-nylon and / or 12-nylon.

  The protective layer 30 can be mounted on the outer periphery of the tube main body 20 and has an inner diameter that is in close contact with the tube main body 20 expanded in diameter by the annular protrusion 51 when the resin tube 10 is press-fitted into the pipe connection portion 50. . In particular, in the press-fit portion 21 of the tube main body 20, stress in the diameter increasing direction is applied to the tube main body 20 by the annular protrusion 51, and stress cracks are likely to occur. This stress crack reduces the chemical resistance and water absorption resistance of the tube body 20, but since it is covered with the protective layer 30, sufficient chemical resistance and water absorption resistance are obtained, which is particularly effective. . The protective layer 30 only needs to be long enough to cover the press-fit portion 21 of the tube body 20. For example, the protective layer 30 may be partially attached to both ends of the tube body 20, and is attached over the entire length of the tube body 20. May be.

  The resin composition mainly composed of 6,6-nylon constituting the tube main body 20 and the resin composition mainly composed of 11-nylon and / or 12-nylon constituting the protective layer 30 are this kind of resin. Various additives commonly used in materials such as copper halides, hindered phenol compounds, aromatic amines and other heat-resistant agents, phenolic, thioether-based, phosphite-based, amine-based antioxidants, salicylate-based , UV absorbers such as benzophenone, benzotriazole, imidazole, oxazole, hindered amine, cyanoacrylate, metal complex, phenyl salicylate, weather resistance such as carbon black, copper compound, hindered amine, phosphorous acid manganese salt Property improvers, alkylamines, alkylamides, alkyls Antistatic agents such as ether, alkyl phenyl ether, glycerin fatty acid ester, sorbitan fatty acid ester, alkyl sulfonate, alkyl benzene sulfonate, alkyl sulfate, alkyl phosphate, quaternary ammonium salt, alkyl betaine, red phosphorus, tin oxide, zirconium hydroxide Inorganic flame retardants such as barium metaborate, aluminum hydroxide and magnesium hydroxide, organic flame retardants based on halogen, phosphate ester, melamine or cyanuric acid, flame retardant aids such as antimony trioxide, and hindered amines Contains heat stabilizers such as tin compounds and epoxy compounds, wear resistance improvers such as molybdenum disulfide, graphite, polyethylene, polytetrafluoroethylene, and silicone, release agents, oils, pigments, dyes, etc. Shi It can have. Further, a reinforcing material such as glass fiber may be added to the tube body and / or the protective layer.

  The ratio between the thickness of the tube body 20 and the thickness of the protective layer 30 is not particularly limited, but is preferably 1: 0.1 to 1, more preferably 1: 0.2 to 0.5. Moreover, the thickness of the tube body 20 is preferably 0.8 to 2 mm, more preferably 1 to 1.2 mm, and the thickness of the protective layer 30 is preferably 0.1 to 2 mm, more preferably 0.00. 2 to 0.6 mm.

  As shown in FIG. 3, the resin tube 10 can be used as a fuel vapor pipe disposed in a metal fuel tank 80 of an automobile. In this case, the end portion of the resin tube 10 is press-fitted into a connection portion (not shown) of the connector 60 and connected to the connector 60. And this connector 60 is inserted in the piping connection part, joint, etc. of the fuel cutoff valve 70, and the resin tube 10 is piped. The fuel shut-off valve 70 is attached to the upper surface of the inner wall of the fuel tank 80, and sends fuel vapor from the fuel tank 80 to a canister or the like (not shown) via an exhaust pipe 71 protruding outside the fuel tank 80. When the valve rises, the valve is closed by a built-in float valve so that the fuel does not flow into the resin tube 10.

  The fuel vapor pipe is preliminarily disposed in the metal fuel tank 80, and the tank is painted and dried after the fuel tank 80 is joined. Exposed to. However, in this embodiment, since the tube body 20 is mainly made of 6,6-nylon as described above, the connection strength can be sufficiently maintained without being deformed even at a high temperature as described above. Moreover, since the outer periphery of the tube 20 is covered with the protective layer 30 mainly composed of 11-nylon and / or 12-nylon, it is possible to prevent the tube body 20 from being cracked. Moreover, although the temperature of 160 degreeC becomes higher than the heat deformation temperature of 11-nylon and 12-nylon, since the protective layer 30 is supported by the tube main body 20 with heat resistance, a deformation | transformation does not occur. Furthermore, although water, acids and amines resulting from the fuel decomposition products are generated in the fuel tank 80, the press-fitting part 21 to the pipe connection part 50 is protected by the protective layer 30. Deterioration of the tube main body 20 of the portion 21 is prevented, and the connection strength and sealing performance can be maintained over a long period of time.

  In addition, melting | fusing point and heat deformation temperature (use temperature upper limit) of 6, 6-nylon, 11-nylon, 12-nylon are as shown in Table 1 below.

  FIG. 4 shows a second embodiment of the resin tube according to the present invention. Note that substantially the same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  Similar to the first embodiment, the resin tube 11 includes a tube body 20 made of a resin composition mainly composed of 6,6-nylon. And the protective layer 30 which consists of a resin composition which has 11-nylon and / or 12-nylon as a main component is coat | covered on the outer periphery over the full length of this tube main body 20. As shown in FIG. The tube main body 20 and the protective layer 30 are formed by co-extrusion molding to form a multilayer tube (in this embodiment, a two-layer tube). In addition, the material of the tube main body 20 and the protective layer 30, and each thickness should just be the same as that of the said 1st Embodiment.

  Also in this embodiment, heat resistance by 6,6-nylon, chemical resistance by 11-nylon and / or 12-nylon, and water absorption resistance can be obtained, and disposed in a fuel vapor pipe of an automobile or an engine room. As the piping to be used, it can be particularly preferably used.

  FIG. 5 shows a third embodiment of the resin tube according to the present invention. It should be noted that substantially the same parts as those of the above embodiments are denoted by the same reference numerals and description thereof is omitted.

  Similar to the second embodiment, the resin tube 12 has a tube body 20 made of a resin composition mainly composed of 6,6-nylon, and has an outer periphery over the entire length of the tube body 20. , 11-nylon and / or 12-nylon as a main component, a protective layer 30 made of a resin composition is coated. Furthermore, in this embodiment, the 2nd protective layer 31 which consists of a resin composition which has 11-nylon and / or 12-nylon as a main component is coat | covered also at the inner periphery of the tube main body 20. FIG. The protective layer 30, the tube main body 20, and the second protective layer 31 are formed by coextrusion molding to form a multilayer tube (three-layer tube in this embodiment).

  In this embodiment, since the protective layer 31 made of 11-nylon and / or 12-nylon is coated not only on the outer periphery of the tube body 20 made of 6,6-nylon but also on the inner periphery, the resin tube 12 It is also possible to effectively prevent deterioration caused by a compound or water contained in the fluid flowing in the interior. Moreover, by using a three-layer structure, more excellent strength and heat resistance can be obtained.

The fragmentary sectional view which shows 1st Embodiment of the resin tube for automobile piping by this invention Sectional drawing along the AA arrow line of FIG. Explanatory drawing showing a state where the resin tube is applied to a fuel vapor pipe incorporated in a metal fuel tank The fragmentary sectional view which shows 2nd Embodiment of the resin tube for motor vehicle piping by this invention Partial sectional drawing which shows 3rd Embodiment of the resin tube for motor vehicle piping by this invention.

Explanation of symbols

10, 11, 12 Resin tube 20 Tube body 21 Press-fit portion 30 Protective layer 31 Second protective layer 80 Fuel tank

Claims (2)

  In the resin tube that is press-fitted and attached to the outer periphery of the automobile pipe connection portion, at least the tube body formed mainly of 6,6-nylon and at least the outer periphery of the portion that is press-fitted into the pipe connection portion of the tube body are covered. A resin tube for automobile piping, characterized by comprising a protective layer mainly made of 11-nylon and / or 12-nylon.   The resin tube for automobile piping according to claim 1, wherein the protective layer is extruded simultaneously with the tube main body so as to cover the entire length of the tube main body.

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