JP4896897B2 - Gasohol fuel hose - Google Patents

Description

  The present invention relates to a gasohol fuel hose used as a piping for transporting alcohol-mixed gasoline (gasohol) fuel.

In recent years, regulations on the transpiration of fuel gas surrounding automobiles have become stricter, and it has been required to significantly reduce the amount of fuel transpiration from fuel hoses, and various low-permeability automotive fuel hoses corresponding to this have been studied. ing. Such fuel-based hoses include, for example, (a) a relatively thin inner layer in the form of an elastomer of FKM fluoropolymer, and (b) a thermoplastic of THV fluoropolymer extruded in tubular form on the inner FKM layer. A relatively thin intermediate layer or layers of the molded body, wherein the FKM inner layer and the intermediate THV layer are integral and have a thickness sufficient to provide a sufficient barrier against volatile hydrocarbon leakage. Fuel refueling hoses for transporting volatile hydrocarbons have been proposed (e.g., patents) comprising a layer, and (c) a durable outer layer of elastomeric polymer that adheres to and covers the same range of the outer surface of the intermediate layer. Reference 1).
JP 2005-52239A

  However, the fuel refueling hose described in Patent Document 1 is intended to transport volatile hydrocarbons. If gasoline is not mixed with alcohol, the permeation resistance to the hydrocarbon vapor is Although satisfactory, an alcohol-mixed gasoline (gasohol) fuel mixed with a high-permeability alcohol such as ethanol has insufficient permeation resistance to alcohol vapor.

  This invention is made | formed in view of such a situation, The objective is to provide the hose for gasohol fuels excellent in alcohol-resistant fuel permeability.

  In order to achieve the above object, a gasohol fuel hose of the present invention is a gasohol fuel hose comprising a tubular inner layer and an alcohol barrier layer formed on the outer periphery thereof, wherein the inner layer is tetrafluoro An alcohol-blocking layer comprising a composition containing an ethylene-hexafluoropropylene-vinylidene fluoride terpolymer or a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether quaternary copolymer, Is made of a rubber composition containing butyl rubber.

  That is, the present inventors have made extensive studies in order to obtain a gasohol fuel hose excellent in alcohol fuel permeation resistance. Butyl rubber is inferior in hydrocarbon fuel oil resistance and poor in fuel permeation resistance, so it was common knowledge that it was not used in fuel hoses, but the inventors continued their experiments focusing on butyl rubber. As a result, it was found that butyl rubber has excellent alcohol fuel permeability. And the hose provided with the alcohol barrier layer made of a rubber composition containing butyl rubber was found to be excellent in permeation resistance to alcohol-mixed gasoline (gasohol), and reached the present invention.

  Thus, the gasohol fuel hose of the present invention includes a tubular inner layer and an alcohol barrier layer formed on the outer periphery thereof, and the inner layer is formed of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride ternary copolymer. It consists of a composition or a composition containing tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether quaternary copolymer, and the alcohol barrier layer is made of a rubber composition containing butyl rubber. Therefore, of the fuel vapor flowing in contact with the tubular inner layer, the permeation of hydrocarbon vapor is almost completely suppressed, and the permeation of alcohol vapor is considerably suppressed. And permeation | transmission of the alcohol which permeate | transmitted is completely suppressed by the alcohol barrier layer which consists of a rubber composition containing a butyl rubber. In this case, although butyl rubber lacks hydrocarbon fuel oil resistance, the hydrocarbon fuel vapor is not influenced by the inner layer because it is blocked by the inner layer. Therefore, the hose for gasohol fuel of the present invention is excellent in permeation resistance to alcohol-mixed gasoline (gasohol). In addition, from the composition in which the inner layer contains a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer or a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether quaternary copolymer. Therefore, it is excellent in fuel oil resistance.

  And when the said alcohol barrier layer consists of a rubber composition containing a hydrous hydrotalcite compound and 1,8-diazabicyclo (5,4,0) undecene-7 salt (DBU salt), the said hydrous hydrotalcite Due to the synergistic effect of the excellent acid-accepting effect of the compound and the effect of accelerating the vulcanization of the DBU salt, the interlaminar adhesion between the alcohol blocking layer and the layer in contact therewith is further improved.

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

  As the gasohol fuel hose of the present invention, for example, as shown in FIG. 1, the inner layer 2, the intermediate layer 3, and the alcohol barrier layer (outer layer) 4 are sequentially formed on the outer peripheral surface of the tubular innermost layer 1. The thing of a structure is mention | raise | lifted. The gasohol fuel hose according to the present invention is not limited to the four-layer structure shown in FIG. 1, and may have any alcohol-blocking layer 4 formed on the outer periphery of the tubular inner layer 2. . Note that a layer may be formed on the outer peripheral side of the alcohol blocking layer 4.

  In the present invention, the inner layer 2 contains a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer or a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether quaternary copolymer. The alcohol barrier layer 4 is characterized by comprising a rubber composition containing butyl rubber.

  In the present invention, the alcohol-mixed gasoline (gasohol) fuel refers to a fuel having an alcohol mixture amount of several percent to 100%. Gasohol fuel generally has the highest transmittance when the alcohol content is 10 to 20%. Examples of the alcohol include ethanol and methanol, and ethanol is usually used.

  As a rubber component of the rubber composition (the material for the innermost layer) forming the innermost layer 1, for example, a blend rubber (NBR-PVC) of acrylonitrile-butadiene rubber (NBR), polyvinyl chloride and (PVC), or NBR A single unit is used.

  The content of the rubber component (NBR-PVC or NBR alone) is usually 40% by weight or more of the entire innermost layer material (rubber composition).

  Examples of the NBR include those in which the amount of acrylonitrile (AN amount) is medium-high AN, high AN, and extremely high AN. From the viewpoint of fuel oil resistance, those having an AN amount in the range of 25 to 60 are preferable, and particularly preferable. AN amount is in the range of 30 to 55. Extremely high ANs have the advantage of improved gasoline permeation resistance, and better resistance to gasoline and ozone. Middle and high ANs are slightly inferior to those of extreme high ANs, but are resistant to gasoline permeation. There is an advantage that the property is improved.

  Moreover, the blend ratio (weight ratio) of NBR and PVC in the NBR-PVC is preferably in the range of NBR / PVC = 90/10 to 40/60, particularly preferably NBR / PVC = from the viewpoint of ozone. It is in the range of 80/20 to 50/50.

  The innermost layer material includes, in addition to the rubber component, carbon black, an antioxidant, a vulcanizing agent (crosslinking agent), a vulcanization accelerator (crosslinking accelerator), and a vulcanization aid (crosslinking aid). ), Processing aids, white fillers, plasticizers, softeners, acid acceptors, colorants, scorch inhibitors and the like may be added as appropriate.

  Next, as the inner layer material (resin composition) for forming the inner layer 2, tetrafluoroethylene (TFE) -hexafluoropropylene (HFP) -vinylidene fluoride (VDF) terpolymer or tetrafluoroethylene- A specific thermoplastic fluororesin composed of a quaternary copolymer of hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether is used.

  The content of the specific thermoplastic fluororesin is usually 50% by weight or more of the entire inner layer material (resin composition), and the inner layer material may be composed of only the specific thermoplastic fluororesin. Absent.

  In addition to the specific thermoplastic fluororesin, a conductive agent, a plasticizer, a pigment, and the like may be appropriately added to the inner layer material as long as the object of the present invention is not impaired.

  Examples of the rubber component of the rubber composition (interlayer material) forming the intermediate layer 3 include, for example, a blend rubber (NBR-PVC) of acrylonitrile-butadiene rubber (NBR), polyvinyl chloride, and (PVC), Alternatively, NBR alone is used.

  The content of the rubber component (NBR-PVC or NBR alone) is usually 40% by weight or more of the entire intermediate layer material (rubber composition).

  Examples of the NBR include those in which the amount of acrylonitrile (AN amount) is medium-high AN, high AN, and extremely high AN. From the viewpoint of fuel oil resistance, those having an AN amount in the range of 25 to 60 are preferable, and particularly preferable. AN amount is in the range of 30 to 55. Extremely high ANs have the advantage of improved gasoline permeation resistance, and better resistance to gasoline and ozone. Middle and high ANs are slightly inferior to those of extreme high ANs, but are resistant to gasoline permeation. There is an advantage that the property is improved.

  Moreover, the blend ratio (weight ratio) of NBR and PVC in the NBR-PVC is preferably in the range of NBR / PVC = 90/10 to 40/60, particularly preferably NBR / PVC = from the viewpoint of ozone. It is in the range of 80/20 to 50/50.

  In addition to the rubber component, the intermediate layer material includes carbon black, an antioxidant, a vulcanizing agent (crosslinking agent), a vulcanization accelerator (crosslinking accelerator), and a vulcanization aid (crosslinking aid). ), Processing aids, white fillers, plasticizers, softeners, acid acceptors, colorants, scorch inhibitors and the like may be added as appropriate.

  Next, butyl rubber is used as the rubber composition (the material for the alcohol barrier layer) that forms the alcohol barrier layer 4.

  The butyl rubber may be a copolymer of isobutylene and isoprene, and examples thereof include regular butyl rubber and halogenated butyl rubber (brominated butyl rubber, chlorinated butyl rubber, etc.). These may be used alone or in combination of two or more.

  The content of the butyl rubber is preferably 50% by weight or more of the entire alcohol barrier layer material (rubber composition), and the alcohol barrier layer material may be composed of butyl rubber alone.

  In addition, from the point of interlayer adhesiveness, the said alcohol barrier layer material uses a hydrous hydrotalcite compound and 1,8-diazabicyclo (5,4,0) undecene-7 salt (DBU salt) in combination. There is no problem.

Examples of the hydrous hydrotalcite compound include Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3.5H ₂ O, Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ , Mg ₄ Al ₂ (OH) ₁₂ CO _3. 3.5H ₂ O, Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O, Mg ₅ Al ₂ (OH) ₁₄ CO ₃ .4H ₂ O, Mg ₃ Al ₂ (OH) ₁₀ CO ₃ .1.7H ₂ O, Mg ₃ ZnAl ₂ (OH) ₁₂ CO ₃ .wH ₂ O, Mg ₃ ZnAl ₂ (OH) ₁₂ CO _{3 and the} like. These may be used alone or in combination of two or more. Specific examples of the hydrous hydrotalcite compound include DHT-4A manufactured by Kyowa Chemical Industry Co., Ltd., DHT-6 manufactured by Kyowa Chemical Industry Co., Ltd., and the like.

  The amount of the hydrous hydrotalcite compound is preferably in the range of 1 to 15 parts, particularly preferably 100 parts by weight (hereinafter abbreviated as “parts”) from the viewpoint of obtaining an excellent acid accepting effect. It is in the range of 2-6 parts. That is, if the amount of the hydrous hydrotalcite compound is too small, the desired acid-accepting effect cannot be obtained and the compression set is deteriorated. Conversely, the amount of the hydrous hydrotalcite compound is too large. This is because the crosslinking may proceed excessively and may adversely affect the physical properties of the rubber.

  Examples of the DBU salt include DBU carboxylate and DBU phenol resin salt. The DBU carboxylate is preferably DBU naphthoate or sorbate. These may be used alone or in combination of two or more. Among these, naphthoic acid salt of DBU (naphthoic acid DBU salt) is preferable in terms of adhesiveness.

  The blending amount of the DBU salt is preferably in the range of 0.1 to 3 parts, particularly preferably in the range of 0.3 to 1 part, with respect to 100 parts of the butyl rubber. That is, if the amount of the DBU salt is too small, the desired interlayer adhesion cannot be obtained, and conversely, if the amount of the DBU salt is too large, cross-linking proceeds too much, which may adversely affect rubber properties and the like. Because there is.

  The gasohol fuel hose of the present invention can be produced, for example, as follows. That is, first, a rubber composition (innermost layer material) containing NBR-PVC or NBR, an inner layer material mainly composed of a specific thermoplastic fluororesin, a rubber composition containing NBR-PVC or NBR (intermediate layer) Layer material) and a rubber composition (material for alcohol barrier layer) containing butyl rubber. Then, the rubber composition (the innermost layer material) is extruded to form the innermost layer 1, and then the inner layer material is coated on the outer peripheral surface to form the inner layer 2. Next, a rubber composition (intermediate layer material) and a rubber composition (alcohol barrier layer material) are respectively extruded on the outer peripheral surface of the inner layer 2 (tandem method). Next, after cutting to a predetermined length, it is inserted into a mandrel and vulcanized (140 to 170 ° C. × 10 to 60 minutes). Pull out from the mandrel after vulcanization to produce a four-layer gasohol fuel hose (see FIG. 1) in which an inner layer 2, an intermediate layer 3, and an alcohol blocking layer 4 are sequentially formed on the outer peripheral surface of the tubular innermost layer 1 Can do.

  The gasohol fuel hose of the present invention is not limited to the above production method.

  In the gasohol fuel hose of the present invention, the innermost layer 1 preferably has a thickness of 0.2 to 4 mm, particularly preferably 0.5 to 3 mm, and the inner layer 2 has a thickness of 0.01 to 0.5 mm. In particular, 0.05 to 0.3 mm, and the thickness of the intermediate layer 3 is preferably 0.2 to 4 mm, particularly preferably 0.5 to 3 mm. The thickness of the blocking layer 4 is preferably in the range of 0.2 to 4 mm, particularly preferably in the range of 0.5 to 3 mm. The hose inner diameter is preferably in the range of 2 to 50 mm, particularly preferably in the range of 5 to 40 mm.

  The gasohol fuel hose of the present invention is not limited to the four-layer structure as shown in FIG. 1, for example, a two-layer structure in which the alcohol barrier layer 4 is directly formed on the outer peripheral surface of the inner layer 2, Alternatively, a three-layer structure in which the intermediate layer 3 is formed on the outer peripheral surface of the inner layer 2 and the alcohol blocking layer 4 is formed on the outer peripheral surface may be used. Further, a layer may be formed on the outer peripheral side of the alcohol blocking layer 4. Further, another layer may be formed between the inner layer 2 and the innermost layer 1.

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

  First, prior to the examples and comparative examples, materials for forming the respective layers of the hose were prepared.

(Preparation of NBR material, NBR-PVC material)
The components shown in Table 1 below were blended in the proportions shown in the same table, and these were kneaded with a banbury and a roll to prepare an NBR material and an NBR-PVC material, respectively.

  The materials shown in Table 1 are as follows.

[Middle-high AN NBR-PVC]
Prototype (AN amount = 35)
[Very high AN NBR-PVC]
Prototype (AN amount = 46)
[Very high AN NBR]
Nipol DN003 manufactured by Nippon Zeon (AN amount = 50)
[High AN NBR]
Nipol DN101 (AN quantity = 42.5), manufactured by Nippon Zeon

〔stearic acid〕
Made by Kao, Lunac S30
[MgO]
Manufactured by Kyowa Chemical Industry Co., Ltd., Kyowa Mug # 150
[DBU salt]
1,8-diazabicyclo- (5,4,0) -undecene-7 salt (DBU salt) manufactured by Daiso Corporation
〔Carbon black〕
SEAST SO manufactured by Tokai Carbon
[Zeolite]
Mizusawa Chemical Industry Co., Ltd.
〔talc〕
Mistrone vapor talc (basic silica) manufactured by Nippon Mytron
DSL. Carplex 1120, manufactured by Japan
[Ether ester plasticizer]
Asahi Denka Kogyo Co., Ltd., Adeka Sizer RS107
[Sulfur (vulcanizing agent)]
Sulfax T-10, manufactured by Karuizawa Refinery
[Vulcanization accelerator (OBS)]
Ouchi Shinsei Chemical Co., Ltd., Noxeller MSA

(Preparation of IIR material)
The components shown in Table 2 below were blended in the proportions shown in the same table, and these were kneaded with a banbury and a roll to prepare an IIR material.

The materials shown in Table 2 are as follows.
[Regular IIR]
Butyl 365, manufactured by JSR
[Halogenated IIR (Cl-IIR)]
Butyl HT1066, manufactured by JSR
〔stearic acid〕
Made by Kao, Lunac S30
〔Carbon black〕
SEAST SO manufactured by Tokai Carbon
[Naphthenic oil]
Idemitsu Kosan Co., Ltd., Diana Process NM-300
[Zinc oxide (crosslinking aid)]
2 types of zinc oxide [resin vulcanizing agent] manufactured by Mitsui Mining & Mining
Tachiroll 201 manufactured by Taoka Chemical Industries

[Naphthoic acid DBU salt]
DA-500, manufactured by Daiso Corporation
[Hydrohydrotalcite]
DHT-4A manufactured by Kyowa Chemical Co., Ltd.
[Crosslinking agent]
Sanshin Chemical Co., Ltd., Sunseller 22C
[Sulfur (vulcanizing agent)]
Sulfax T-10, manufactured by Karuizawa Smelter
[Crosslinking aid]
Ouchi Shinsei Chemical Co., Ltd., Noctizer SS

  Next, the hose was produced using the formation material of each said hose layer.

[Example 1]
A hose was produced using the material for forming each layer shown in Table 3 below. That is, the NBR material 1 as the innermost layer material, the tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether quaternary copolymer (manufactured by Dinion Co., THV815G) as the inner layer material, and the intermediate layer material The NBR-PVC material 1 and the IIR material 1 were prepared as the alcohol barrier layer material, respectively. First, after forming the innermost layer by extruding the innermost layer material, the inner layer was formed by covering the outer peripheral surface with the inner layer material. Next, an intermediate layer material and an alcohol barrier layer material were respectively extruded on the outer peripheral surface of the inner layer. Next, after cutting this to a predetermined length (300 mm), it was inserted into a mandrel and vulcanized (160 ° C. × 30 minutes). After vulcanization, the hull was pulled out from the mandrel, and a four-layer hose (inner diameter: 24 mm) in which an inner layer, an intermediate layer, and an alcohol blocking layer were sequentially formed on the outer peripheral surface of the tubular innermost layer was produced.

[Examples 2-5, 8, 10, 11]
A hose having a four-layer structure was prepared in the same manner as in Example 1, except that the innermost layer material, inner layer material, intermediate layer material, and alcohol barrier layer material shown in Table 3 and Table 4 were changed to the combination. Produced.

Example 6
A hose having a three-layer structure was produced in the same manner as in Example 1 except that no intermediate layer was formed between the inner layer and the alcohol blocking layer. That is, the innermost layer material, inner layer material, and alcohol barrier layer material shown in Table 3 below were prepared. And after forming the innermost layer by extruding the innermost layer material, the outer layer was covered with the inner layer material to form the inner layer. Next, an alcohol blocking layer material was extruded on the outer peripheral surface of the inner layer. Next, after cutting this to a predetermined length (300 mm), it was inserted into a mandrel and vulcanized (160 ° C. × 30 minutes). After vulcanization, the tube was pulled out from the mandrel, and a three-layered hose (inner diameter: 24 mm) in which an inner layer and an alcohol blocking layer were sequentially formed on the outer peripheral surface of the tubular innermost layer was produced.

[Examples 7, 12, and 13, Comparative Example 1]
A hose having a three-layer structure was produced in the same manner as in Example 6 except that the innermost layer material, inner layer material, and alcohol barrier layer material shown in Table 3 and Table 4 were combined.

Example 9
A hose having a three-layer structure was prepared in the same manner as in Example 1 except that the innermost layer was not formed on the inner peripheral surface of the inner layer. That is, an inner layer material, an intermediate layer material, and an alcohol barrier layer material shown in Table 4 below were prepared. And after coat | covering the said material for inner layers on a mandrel, the material for intermediate | middle layers and the material for alcohol barrier layers were extruded on the outer peripheral surface, respectively. Next, after cutting to a predetermined length (300 mm), this was pulled out from the mandrel, inserted into another mandrel, and vulcanized (160 ° C. × 30 minutes). After vulcanization, it was pulled out from the mandrel, and a three-layered hose (inner diameter: 24 mm) was produced in which an intermediate layer and an alcohol blocking layer were sequentially formed on the outer peripheral surface of the tubular inner layer.

  Using the example product and the comparative product thus obtained, each characteristic was evaluated according to the following criteria. The results are also shown in Tables 3 and 4 above.

(Transmission amount)
A metal pipe having an outer diameter of 25.4 mm (having two bulges with a maximum outer diameter of 27.4 mm formed) was press-fitted into both ends of each hose. Then, after attaching a sealing plug to one metal pipe and supplying a test solution (Fuel C + ethanol 10% by volume) into each hose from the other metal pipe, a screw-type sealing plug ( The product of Example 9 was equipped with a quick connector), and the test solution was sealed in each hose. Each hose was held at 40 ° C. for 3000 hours. Then, using the CARB SHED method DBL pattern, the permeation amount of hydrocarbon (HC) was measured for 3 days, and the permeation amount of hydrocarbon (HC) on the day when the permeation amount of hydrocarbon (HC) was the maximum was obtained. The amount.

[Interlayer adhesion]
A test piece having a width of 25.4 mm was cut out from each hose, and the outer layer of the test piece was peeled off at a speed of 50 mm per minute using a tensile tester (JIS B 7721). / Cm) was measured.

  From the results of Tables 3 and 4 above, the example products were provided with an alcohol barrier layer containing butyl rubber, so that the permeation amount of the alcohol-mixed gasoline was small and the alcohol fuel resistance was excellent. Moreover, the adhesive force was especially excellent in Examples 10-13 goods provided with the alcohol barrier layer which consists of IIR materials 3 and 4 containing DBU salt and a hydrous hydrotalcite.

  On the other hand, since the product of Comparative Example 1 was not provided with an alcohol barrier layer containing butyl rubber, the permeated amount of alcohol-mixed gasoline was large and the alcohol fuel resistance was poor.

  The hose for gasohol fuel of the present invention is used as a piping for transporting an alcohol mixed gasoline (gasohol) fuel such as methanol or ethanol.

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

Explanation of symbols

1 innermost layer 2 inner layer 3 intermediate layer 4 alcohol blocking layer

Claims (6)

  Gasohol fuel hose comprising a tubular inner layer and an alcohol barrier layer formed on the outer periphery thereof, wherein the inner layer is a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer or tetrafluoroethylene Gasohol fuel comprising a composition containing a hexafluoropropylene-vinylidene fluoride-perfluoroalkyl vinyl ether quaternary copolymer, and wherein the alcohol blocking layer is made of a rubber composition containing butyl rubber For hose.   2. The gasohol fuel hose according to claim 1, wherein a layer made of a rubber composition containing acrylonitrile-butadiene rubber is provided on the inner periphery of the inner layer.   The hose for gasohol fuel according to claim 1 or 2, further comprising a layer made of a rubber composition containing acrylonitrile-butadiene rubber between the inner layer and the alcohol barrier layer.   The gasohol fuel hose according to claim 2 or 3, wherein the rubber component in the rubber composition containing the acrylonitrile-butadiene rubber is composed of a blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride, or acrylonitrile-butadiene rubber alone.   The hose for gasohol fuel according to any one of claims 1 to 4, wherein the butyl rubber is at least one of regular butyl rubber and halogenated butyl rubber.   The alcohol blocking layer is made of a rubber composition containing a hydrous hydrotalcite compound and 1,8-diazabicyclo (5,4,0) undecene-7 salt (DBU salt). Gasohol fuel hose according to one item.

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