JP2006306015A - Rubber hose for fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber hose for fuel excellent in low permeability of fuel, also flexibility and assembly property, and also low in cost. <P>SOLUTION: The rubber hose comprises a tubular inner layer 1, an intermediate layer 2 provided in contact with its peripheral face and further an outer layer 3 provided in contact with its peripheral face wherein the inner layer 1 includes an acrylonitrile-butadiene rubber (NBR) or the like, wherein the intermediate layer 2 includes a fluororubber dispersed with a flat filler and also wherein the outer layer includes a blend rubber (NBR-PVC) of the acrylonitrile-butadiene rubber and polyvinyl chloride. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a fuel used for transportation of fuels such as automobiles [gasoline, alcohol mixed gasoline, diesel fuel, RME (fatty acid methyl ester) mixed diesel fuel, GTL (Gas to Liquid) mixed diesel fuel, CNG, LPG]. It relates to a rubber 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. Under such circumstances, conventional fuel hoses include, for example, a hose provided with a low-permeability resin layer made of fluorine resin, polyester resin, polyphenylene sulfide resin, or the like. In addition, a material using fluorine rubber (FKM) excellent in low fuel permeability and flexibility as a material for the innermost layer of the fuel hose has already been proposed (see, for example, Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 2-18443 Japanese Patent Laid-Open No. 8-169085

  However, a low-permeability resin layer made of a fluororesin, a polyester resin, or the like is made of resin and has high rigidity. Therefore, the hose is not flexible enough to easily hose assembly. On the other hand, as described in the above-mentioned patent document, in the case of a fuel hose in which low fuel permeability is improved by using a layer made of FKM as a constituent layer, the FKM layer is a rubber layer. Thus, compared with a hose that can achieve low fuel permeability in the resin layer, the flexibility and assemblability are good. However, in order to obtain the desired low fuel permeability by the FKM layer, the thickness of the FKM layer must be increased. And since the material cost of FKM itself is high, the thickness increase of the said FKM layer leads to a cost increase.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a rubber hose for fuel that is excellent in low fuel permeability, excellent in flexibility and assembly property, and low in cost.

In order to achieve the above object, a rubber hose for fuel according to the present invention includes a tubular inner layer, an intermediate layer provided in contact with the outer peripheral surface, and an outer layer provided in contact with the outer peripheral surface. It is configured using (A) below, the intermediate layer is configured using (B) below, and the outer layer is configured using (C) below.
(A) At least one selected from the group consisting of acrylonitrile-butadiene rubber (NBR), blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride (NBR-PVC), and hydrin rubber.
(B) Fluoro rubber in which flat filler is dispersed.
(C) Blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride (NBR-PVC), blend rubber of acrylonitrile-butadiene rubber and ethylene-propylene-diene terpolymer (NBR-EPDM), acrylic rubber (ACM) ), Ethylene acrylic rubber (AEM), ethylene-propylene-diene terpolymer (EPDM), and hydrin rubber.

  That is, the present inventors have intensively studied to solve the above problems. In the course of that research, in order to ensure the flexibility and assemblability of the fuel hose, we recalled that the layer structure was composed only of the rubber layer (so-called “rubber hose”). At the same time, it was also recalled that a fluorine rubber (FKM) layer having excellent fuel low permeability and flexibility is provided as a constituent layer of such a fuel hose. However, as described above, in order to obtain the desired low fuel permeability in the FKM layer, the layer has to be thickened. Therefore, further research has been conducted for this improvement. As a result, when flat filler such as talc is dispersed in the FKM layer, the fuel low permeation performance is enhanced by the blocking action due to the overlapping of the fillers, and the amount of expensive FKM used is inexpensive flat filler. It came to be suppressed according to the blending amount. However, as the above research was further advanced, it became clear that the FKM layer in which the flat filler was dispersed had a problem that the crack extension property to the fuel oil was worse than that of the normal FKM layer. For this reason, as a result of repeated studies centering on this improvement, the present inventors have found that when a specific rubber layer is provided on the inner peripheral surface and the outer peripheral surface of the FKM layer, the intended purpose can be achieved, The present invention has been reached.

  As described above, the fuel hose for fuel according to the present invention includes a tubular inner layer formed using at least one of NBR, NBR-PVC, and hydrin rubber, and an FKM layer (intermediate layer) provided in contact with the outer peripheral surface thereof. Further, a rubber hose provided with an outer layer composed of at least one of NBR-PVC, NBR-EPDM, ACM, AEM, EPDM and hydrin rubber provided in contact with the outer peripheral surface thereof, and has flexibility and assemblability In addition, since the flat filler is dispersed in the FKM layer, it is possible to suppress the usage rate of FKM with high material cost while maintaining excellent low fuel permeability, and to reduce the cost of the hose. Can be realized. In addition, since the FKM layer does not come into direct contact with the fuel, there is no concern about crack extension and the like, so that the fuel hose of the present invention is highly reliable. The fuel hose for fuel of the present invention is particularly suitable as a hose for fuel pipes for automobiles that require excellent flexibility and assembly.

  In particular, when the flat filler dispersed in the FKM layer is talc, mica, montmorillonite or the like, the fuel has low fuel permeability.

  Moreover, when the blending ratio of the flat filler in the FKM layer material is within a predetermined range, the balance of flexibility, barrier properties, and the like is improved.

  Next, an embodiment of the present invention will be described.

  For example, as shown in FIG. 1, the fuel hose for fuel of the present invention is configured such that an intermediate layer 2 is formed on the outer peripheral surface of the inner layer 1, and an outer layer 3 is further formed on the outer peripheral surface thereof. Each of these layers is a rubber layer made of a predetermined rubber.

  As a material for forming the inner layer 1, acrylonitrile-butadiene rubber (NBR), blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride (NBR-PVC), and hydrin rubber are used. These may be used alone or in combination of two or more. Among these, NBR or NBR-PVC is preferable because it is excellent in cost and fuel oil resistance (crack extension). In addition, carbon black, lubricant (stearic acid, etc.), zinc oxide, plasticizer, vulcanizing agent (sulfur, etc.), vulcanization accelerator, vulcanization aid, anti-aging agent, etc. are added to the rubber as necessary. May be blended appropriately.

  In addition, as a material for forming the intermediate layer 2 formed on the outer peripheral surface of the inner layer 1, fluororubber (FKM) in which flat fillers are dispersed is used. Here, the FKM is not particularly limited, and examples thereof include vinylidene fluoride-3 fluoroethylene copolymer, vinylidene fluoride-6 propylene copolymer, and vinylidene fluoride-6 fluoride. Propylene-4 fluoroethylene copolymer, tetrafluoroethylene-propylene copolymer, tetrafluoroethylene-perfluorovinyl ether copolymer, vinylidene fluoride-4 fluoroethylene-perfluoroalkyl vinyl ether copolymer, etc. can give. These may be used alone or in combination of two or more. Of these, vinylidene fluoride-6-propylene-tetrafluoroethylene copolymer is preferred because of its excellent low fuel permeability.

  The flat filler used as the material for forming the intermediate layer 2 is not particularly limited, but talc, mica, and montmorillonite are used in terms of obtaining better fuel low permeability due to the dispersion. It is preferable. In addition, these various flat fillers are used individually or in combination of 2 or more types.

  And the compounding ratio of the flat filler in the formation material of the said intermediate | middle layer 2 is preferable to set it as the range of 10-60 parts with respect to FKM100 weight part (henceforth "part"), More preferably, 20 Within the range of ~ 60 parts. That is, by dispersing the flat filler within such a range, the balance between flexibility and barrier properties is improved.

  In addition, carbon black, a lubricant (wax, etc.), zinc oxide, a vulcanizing agent (peroxide, etc.), an acid acceptor, a vulcanization aid, a colorant, etc. are necessary in the material for forming the intermediate layer 2. Depending on the case, it may be blended appropriately.

  The material for forming the outer layer 3 formed on the outer peripheral surface of the intermediate layer 2 is a blend rubber (NBR-PVC) of acrylonitrile-butadiene rubber and polyvinyl chloride, acrylonitrile-butadiene rubber and ethylene-propylene-diene. A blended rubber (NBR-EPDM), acrylic rubber (ACM), ethylene acrylic rubber (AEM), ethylene-propylene-diene terpolymer (EPDM) and hydrin rubber are used. These may be used alone or in combination of two or more. In addition, since the outer layer 3 normally requires ozone resistance, in the present invention, NBR which is inferior in ozone resistance is excluded from the material for forming the outer layer 3.

  In addition, carbon black, lubricant (such as stearic acid), flame retardant, zinc oxide, plasticizer, vulcanizing agent (such as sulfur), vulcanization accelerator, vulcanization aid, and aging are also included in the material for forming the outer layer 3. An inhibitor, an acid acceptor and the like may be appropriately blended as necessary.

  Here, the rubber hose for fuel of the present invention can be manufactured, for example, as follows. That is, first, the material for the inner layer 1, the material for the intermediate layer 2, and the material for the outer layer 3 are prepared, and these are kneaded using a kneader, and then the three layers are simultaneously extruded using an extruder. By molding, a desired rubber hose for fuel with a three-layer structure can be obtained (see FIG. 1). In addition, during hose vulcanization, the interface of each layer is firmly bonded without an adhesive, and lamination is integrated.

  In addition, a hose with a straight shape or a bellows structure using a corrugator can be formed by a vacuum sizing method or the like.

  The method for producing the fuel rubber hose shown in FIG. 1 is not limited to the method for simultaneously extruding and laminating the layers as described above. For example, first, the material for the inner layer 1 is mixed with a kneader. And kneading, and extruding it with an extruder to form a single-layered hose, and by sequentially extruding the intermediate layer 2 and the outer layer 3 on the outer peripheral surface of the hose using an extruder. A target three-layer rubber hose for fuel may be produced. In addition, although the interface of each said layer is normally adhere | attached without an adhesive agent, you may use an adhesive agent supplementarily depending on the case. Further, if necessary, reinforcing yarn (polyester, vinylon, aramid, nylon, etc.) may be put between the layers.

  The thickness of each layer of the rubber hose for fuel of the present invention thus obtained is such that the thickness of the inner layer 1 is usually 0.05 to 3 mm, preferably 0.1 to 2 mm. The intermediate layer 2 has a thickness of usually 0.05 to 1 mm, preferably 0.1 to 0.5 mm. Moreover, the thickness of the outer layer 3 is usually 0.05 to 3 mm, preferably 0.1 to 2 mm. And the internal diameter of the rubber hose for fuel of this invention is 2-30 mm normally, Preferably it is 5-25 mm.

  The fuel hose for fuel of the present invention is not limited to the three-layer structure as shown in FIG. 1. For example, a rubber layer (innermost layer) is provided on the inner peripheral surface of the inner layer 1, A rubber layer (outermost layer) may be provided on the outer peripheral surface.

  Next, examples will be described together with comparative examples.

(Preparation of inner layer material)
100 parts of NBR (Nippon ZEON Corporation, Nipol DN-202), 100 parts of carbon black (Mitsubishi Chemical Corporation, Dia Black G), 1 part of processing aid (Kao Corporation, LUNAC S-30), plastic 20 parts agent (Daihachi Chemical Industry Co., Ltd., DOP), anti-aging agent (Ouchi Shinsei Chemical Industry Co., Ltd., Nocrack AW and Nocrack 810NA) 3 parts each, vulcanization accelerator (Mitsui Metals Mining Co., Ltd. oxidation) 5 parts of zinc (2 types), 0.5 part of vulcanizing agent (manufactured by Karuizawa Smelter, Sulfax T-10), and vulcanization accelerator (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., Noxeller TT and Noxeller CZ) 1.5 parts of each was kneaded using a kneader to prepare an inner layer material.

(Preparation of intermediate layer material)
100 parts of FKM (Daikin Kogyo Co., Ltd., Daiel G555), 30 parts of talc (manufactured by Nippon Stron, Mistron Paper Talc), 5 parts of carbon black (manufactured by Tokai Carbon Co., Ltd., Seast S), and magnesium oxide (Kyowa Chemical) An intermediate material was prepared by kneading 3 parts of Kyowa Mag # 150) manufactured by Kogyo Co., Ltd. and 6 parts of calcium hydroxide (Caldick 2000 manufactured by Omi Chemical Industry Co., Ltd.) using a kneader.

(Preparation of outer layer material)
100 parts of hydrin rubber (manufactured by Nippon Zeon Co., Ltd., Zeklon 3100), 5 parts of vulcanization accelerator (manufactured by Kyowa Chemical Industry Co., Ltd., Kyowa Mag # 150), 60 parts of carbon black (manufactured by Tokai Carbon Co., Ltd., Seast SO), 10 parts of plasticizer (DOP, manufactured by Daihachi Chemical Industry Co., Ltd.), 1 part of an anti-aging agent (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., NOCRACK NBC), 2 parts of stearic acid (manufactured by Kao Corporation, LUNAC S-30) Then, 1 part of a vulcanizing agent (manufactured by Zeon Corporation, JIS NET F) was kneaded using a kneader to prepare an outer layer material.

[Production of hose]
By preparing materials for each layer prepared in advance as described above, and then simultaneously extruding each layer using an extruder, an intermediate layer having a thickness of 0.5 mm and an intermediate layer having a thickness of 0.2 mm are used. A three-layer fuel hose (inner diameter: 12 mm) having a layer and an outer layer having a thickness of 0.3 mm was produced.

  The blending ratio of talc in the intermediate layer material of Example 1 was reduced to 10 parts. Other than that was carried out similarly to Example 1, and produced the fuel hose of the three-layer structure.

  The blending ratio of talc in the intermediate layer material of Example 1 was increased to 60 parts. Other than that was carried out similarly to Example 1, and produced the fuel hose of the three-layer structure.

  Instead of talc in the intermediate layer material of Example 1, mica [Lepco (Canada Mica), S-150H] was used. Other than that was carried out similarly to Example 1, and produced the fuel hose of the three-layer structure.

  Instead of talc in the intermediate layer material of Example 1, montmorillonite (Hojoen Co., Ltd., Sven NX) was used. Other than that was carried out similarly to Example 1, and produced the fuel hose of the three-layer structure.

  110 parts of a blend rubber of acrylonitrile-butadiene rubber and ethylene-propylene-diene terpolymer (manufactured by JSR, NE61) (masterbatch containing 5 parts of HAF carbon black and 5 parts of zinc oxide), carbon black (Showa Cabot, Show Black N330) 50 parts, processing aid (Kao Corporation, Lunac S-30) 1 part, plasticizer (Daihachi Chemical Industry Co., Ltd., DOP) 15 parts, and anti-aging agent (Crampton, Nowguard 445) 2 parts, vulcanizing agent (Karuizawa Smelter, Sulfax T-10) 0.5 part, vulcanizing agent (Nippon Yushi Co., Perhexa 25B-40) 2 Part and 2 parts of a vulcanization accelerator (manufactured by Sanshin Chemical Co., Ltd., Sunseller CZ) were kneaded using a kneader to prepare an outer layer material. Then, this preparation material was used in place of the outer layer material of Example 1 above. Other than that was carried out similarly to Example 1, and produced the fuel hose of the three-layer structure.

[Comparative Example 1]
The intermediate layer material of Example 1 was free from fillers such as talc. Other than that was carried out similarly to Example 1, and produced the fuel hose of the three-layer structure.

[Comparative Example 2]
Instead of the intermediate layer material of Example 1, a thermoplastic fluororesin (Dyneon, THV-500G) was used to form an intermediate layer having a thickness of 0.1 mm. Other than that was carried out similarly to Example 1, and produced the fuel hose of the three-layer structure.

[Comparative Example 3]
The intermediate layer material of Example 1 was used as the inner layer material, and the inner layer material of Example 1 was used as the intermediate layer material. Other than that was carried out similarly to Example 1, and produced the fuel hose of the three-layer structure.

  Using the fuel hose of the example product and the comparative product thus obtained, each characteristic was evaluated according to the following criteria. These results are shown in Tables 1 and 2 below.

[Gasoline permeation]
Fuel C / E10 (Fuel C: ethanol = 90% by volume: 10% by volume) was sealed in each hose, left standing at 40 ° C. for 168 hours, then drained, and new Fuel C / E10 was sealed again. And left at 40 ° C. for 168 hours. Then, the weight change of this renewed fuel enclosure was measured before and after standing for 168 hours, and the fuel permeation amount (mg) per 1 m of hose was calculated. This operation was performed for 2000 hours in total and calculated every 168 hours to calculate the average fuel permeation amount.

[Flexibility]
Each hose was wound around a tubular cylinder (mandrel) having a diameter of 24 mm, and the flexibility was evaluated based on the degree of winding. In other words, those that were not kinked (buckled) by the above winding were marked with ○, those that were not kinked, and those that were not kinked but had a hose outer diameter of 1/2 or less were marked with ×. did.

(Crack extension)
A JIS No. 1 dumbbell cut out from the inner layer of each hose has a notch wound, and this dumbbell is stretched 50% and immersed in Fuel C (ethanol 10%) at 40 ° C., and the time until cutting is measured. did. As a result, the fuel oil resistance was evaluated as x for those cut in less than 30 seconds and ◯ for 30 seconds or longer.

  From the above results, all of the example products have a small amount of gasoline permeation because of the flat filler such as talc dispersed in the intermediate layer material, and also have flexibility (assembly property) and crack extension. Excellent. In addition, since the intermediate layer of the hose of the above embodiment is not a pure FKM layer, the product of the embodiment is low in cost.

  On the other hand, the product of Comparative Example 1 does not contain a flat filler such as talc in the intermediate layer, so it has poor gasoline low permeability, and the intermediate layer is a pure FKM layer. Cost is higher than the typical products. The product of Comparative Example 2 has an intermediate layer that is a fluororesin layer, and is poor in flexibility (assembly property). In Comparative Example 3, the intermediate layer material and the inner layer material of Example 1 were reversed, but the inner layer was inferior in crack extension.

  On the other hand, the present inventors replaced NBR-PVC or hydrin rubber instead of NBR which is the material for the inner layer of the above example, or NBR- instead of hydrin rubber which is the material for the outer layer of the above example. Even when PVC, ACM, AEM, and EPDM are used, it is confirmed by experiments that the gasoline has low permeability, flexibility (assembly property), and crack extension, as in the other examples.

  The fuel rubber hose of the present invention is mainly suitably used for a fuel hose for automobiles, but can also be used for a tractor, a cultivator, a ship and the like.

It is a block diagram which shows an example of the rubber hose for fuels of this invention.

Explanation of symbols

1 Inner layer 2 Middle layer 3 Outer layer

Claims (3)

A tubular inner layer; an intermediate layer provided in contact with the outer peripheral surface; and an outer layer provided in contact with the outer peripheral surface. The inner layer is configured by using the following (A). A rubber hose for fuel, characterized in that the outer layer is constructed using the following (C).
(A) At least one selected from the group consisting of acrylonitrile-butadiene rubber (NBR), blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride (NBR-PVC), and hydrin rubber.
(B) Fluoro rubber in which flat filler is dispersed.
(C) Blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride (NBR-PVC), blend rubber of acrylonitrile-butadiene rubber and ethylene-propylene-diene terpolymer (NBR-EPDM), acrylic rubber (ACM) ), Ethylene acrylic rubber (AEM), ethylene-propylene-diene terpolymer (EPDM), and hydrin rubber.   2. The rubber hose for fuel according to claim 1, wherein the flat filler dispersed in the intermediate layer is at least one selected from the group consisting of talc, mica and montmorillonite.   The rubber hose for fuel according to claim 1 or 2, wherein a blending ratio of the flat filler in (B) is set in a range of 10 to 60 parts by weight with respect to 100 parts by weight of the fluororubber.

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