JP4906569B2 - Fuel hose and manufacturing method thereof - Google Patents

Description

  The present invention relates to a fuel hose and a manufacturing method thereof.

  In recent years, the atmospheric temperature in an engine room has increased due to the downsizing of automobiles and the like, and the components provided in the engine room are required to have durability that can function sufficiently even under severe use conditions.

  From such a demand, as a fuel hose for an automobile, a fluororubber having better heat resistance, heat aging resistance and the like has been used from one made of nitrile rubber.

  However, since fluororubber is expensive, generally, a fuel hose is formed by forming only the innermost layer of the main body portion with fluororubber and coating the outside with other rubber types.

  Patent Document 1 discloses a fuel hose having an inner layer of tetrafluoroethylene / ethylene copolymer resin and an outer layer of epichlorohydrin rubber or the like.

  Patent Document 2 discloses a fuel hose including a fluorine-based rubber inner layer to which a predetermined additive is added and an epichlorohydrin-based rubber outer layer.

  Patent Documents 3 and 4 disclose a fuel hose provided with an inner layer of fluorine-based rubber and an outer layer of epichlorohydrin-based rubber to which a predetermined additive is added.

  Patent Document 5 discloses a fuel hose having an inner layer of fluorine-based rubber and an outer layer of polar group-containing rubber.

Patent Document 6 discloses a fuel hose in which a fluororesin tube is covered with a protector.
JP-A-5-164273 JP 2006-213874 A Japanese Examined Patent Publication No. 61-29619 Japanese Patent No. 2810429 Japanese Examined Patent Publication No. 6-152165 Japanese Patent No. 3683006

  By the way, there is a problem that fluorine-based materials generally have low adhesion and it is difficult to form a composite member.

  An object of the present application is to provide a fuel hose having high adhesion between the inner layer and the intermediate layer and between the intermediate layer and the outer layer, and excellent in unity, and a method for manufacturing the fuel hose.

A fuel hose according to the present invention that achieves the above object is as follows.
An inner layer formed of a mixed composition of a fluororesin and a vinylidene fluoride rubber;
An intermediate layer provided to cover the inner layer and formed of the first crosslinked rubber composition;
An outer layer provided to cover the intermediate layer and formed of the second crosslinked rubber composition;
Is integrally formed.

  According to the above configuration, the inner layer is formed of the mixed composition of the fluororesin and the vinylidene fluoride rubber, the intermediate layer is formed of the first crosslinked rubber composition, and the outer layer is the second crosslinked layer. It is formed of a rubber composition, and by combining them, high adhesion between the inner layer and the intermediate layer and between the intermediate layer and the outer layer can be obtained, and the integrity of the inner layer, the intermediate layer, and the outer layer is excellent. It becomes.

  From the viewpoint that higher adhesion between the layers can be obtained, in the fuel hose according to the present invention, the fluororesin is preferably an ethylene / tetrafluoroethylene copolymer resin. Moreover, it is preferable that the mixing mass ratio (fluorine resin / vinylidene fluoride rubber) of the fluororesin and the vinylidene fluoride rubber is 60/40 to 99/1, and is 80/20 to 95/5. It is more preferable. Furthermore, the first crosslinked rubber composition forming the intermediate layer is preferably an epichlorohydrin rubber composition, particularly preferably an epichlorohydrin / ethylene oxide copolymer rubber composition, and the first crosslinked rubber composition It is preferable that the product contains a bisphenol A type epoxy resin. Moreover, it is preferable that the 2nd crosslinked rubber composition which forms the said outer layer is a rubber composition which has a nitrile rubber as a main component.

  The method of manufacturing a fuel hose according to the present invention includes a tubular body for forming an inner layer formed of a mixed composition of a fluororesin and a vinylidene fluoride rubber, and a first uncrosslinked structure for forming an intermediate layer. The rubber composition is coated with a second uncrosslinked rubber composition for constituting the outer layer, and these are heated and pressurized to crosslink the first and second uncrosslinked rubber compositions. The whole is integrated.

  The method of manufacturing a fuel hose according to the present invention includes a method by three-layer coextrusion molding, a method in which an inner layer and an intermediate layer are two-layer coextrusion molding, and then an outer layer is extruded on the two layers. The method can be applied to any of a method of blow molding or coating the inner layer after molding, a method of injection molding, or a method of blow molding.

  According to the present invention, the above-described combination of the material configurations of the inner layer, the intermediate layer, and the outer layer provides high adhesion between the inner layer and the intermediate layer and between the intermediate layer and the outer layer, thereby obtaining excellent integrity. it can.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

  FIG. 1 shows a fuel hose 10 according to the present embodiment. The fuel hose 10 is used, for example, for communication between a fuel injection pipe of an automobile and a fuel tank.

  The fuel hose 10 has a three-layer structure of an inner layer 11, an intermediate layer 12 provided so as to cover the inner layer 11, and an outer layer 13 provided so as to further cover the intermediate layer 12. The fuel hose 10 is formed in a cylindrical tube shape having a length of 100 to 1000 mm, an outer diameter of 32 to 72 mm, and an inner diameter of 25 to 60 mm, for example.

  The inner layer 11 is formed of a mixed composition of a fluororesin and a vinylidene fluoride rubber. The inner layer 11 has a layer thickness of, for example, 0.05 to 1.0 mm.

  Examples of the fluororesin include an ethylene / tetrafluoroethylene copolymer (ETFE) resin, a polytetrafluoroethylene (PTFE) resin, a polyvinylidene fluoride (PVDF) resin, and the like. Of these, ethylene / tetrafluoroethylene copolymer (ETFE) resin is preferable from the viewpoint that higher adhesion to the intermediate layer 12 can be obtained. The ethylene / tetrafluoroethylene copolymer (ETFE) resin may be modified with, for example, an epoxy group, a maleic anhydride group, a carbonyl group, or the like. Specific examples of the ethylene / tetrafluoroethylene copolymer (ETFE) resin include trade name Fluon manufactured by Asahi Glass Co., Ltd., and trade name NEOFLON manufactured by Daikin Industries. The fluororesin may be composed of a single type of the above, or may be composed of a mixture of multiple types.

  The vinylidene fluoride rubber is a vinylidene fluoride / hexafluoropropylene copolymer (FKM) rubber. Examples of vinylidene fluoride rubber (FKM) include DuPont's trade name Viton, Daikin Industries' trade name Daiel G, and Sumitomo 3M's trade name Dyneon.

  The mixing mass ratio of the fluororesin and the vinylidene fluoride rubber is preferably fluororesin / vinylidene fluoride rubber = 60/40 to 99/1, and more preferably 80/20 to 95/5.

  In addition, the inner layer 11 may contain a plasticizer, an elastomer, and the like.

  The mid layer 12 is formed of the first crosslinked rubber composition. The intermediate layer 12 has a layer thickness of, for example, 0.05 to 1.0 mm.

  The first crosslinked rubber composition is a first uncrosslinked rubber kneaded by adding a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a processing aid, and a reinforcing material (carbon black or the like) to a base rubber. The composition is crosslinked by heating and pressing. The first crosslinked rubber composition may be either a sulfur crosslinked type or a peroxide crosslinked type.

  Examples of the base rubber of the first crosslinked rubber composition include epichlorohydrin-based (CO, ECO) rubber such as epichlorohydrin homopolymer rubber and epichlorohydrin / ethylene oxide copolymer rubber, nitrile rubber (NBR), and nitrile rubber (NBR). ) And polyvinyl chloride (PVC), acrylic rubber (ACM, ANM) and the like. However, among these, from the viewpoint that higher adhesion between the inner layer 11 and the outer layer 13 can be obtained, epichlorohydrin rubber, particularly epichlorohydrin / ethylene oxide copolymer rubber is preferable. Specific examples of the epichlorohydrin rubber include trade name hydrin and Zecron manufactured by Nippon Zeon Co., Ltd., trade name epichromer manufactured by Daiso Corporation, and the like. The base rubber of the first crosslinked rubber composition may be composed of a single kind of the above, or may be composed of a mixture of plural kinds.

  The first crosslinked rubber composition preferably contains a bisphenol A type epoxy resin from the viewpoint that higher adhesion between the inner layer 11 and the outer layer 13 can be obtained.

  The outer layer 13 is formed of a second crosslinked rubber composition. The outer layer 13 is formed with a layer thickness of, for example, 3.5 to 6.0 mm.

  The second crosslinked rubber composition is a second uncrosslinked rubber kneaded by adding a vulcanizing agent, a vulcanization accelerator, an antioxidant, a processing aid, and a reinforcing material (carbon black or the like) to the base rubber. The composition is crosslinked by heating and pressing. The second crosslinked rubber composition may be either a sulfur crosslinked type or a peroxide crosslinked type.

  Examples of the base rubber of the second crosslinked rubber composition include nitrile rubber (NBR). However, higher adhesion to the intermediate layer 12 can be obtained, and from the viewpoint of low cost and ozone resistance, nitrile rubber alone, or other rubber such as nitrile rubber and polyvinyl chloride (PVC) It is preferable to use nitrile rubber as a main component, such as rubber blended with. The base rubber of the second crosslinked rubber composition may be composed of a single kind or a mixture of plural kinds.

  This fuel hose 10 is a method by three-layer coextrusion molding, a method in which the inner layer 11 and the intermediate layer 12 are two-layer coextrusion molding, and then the outer layer 13 is extruded thereon, and the middle layer 12 and the outer layer 13 are two-layer coextrusion After the molding, the inner layer 11 can be produced by any of a blow molding or coating method, an injection molding method, or a blow molding method.

  In any of the above methods, a tubular body for constituting the inner layer 11 formed of a mixed composition of a fluororesin and a vinylidene fluoride rubber is used as a first uncrosslinked rubber composition for constituting the intermediate layer 12. And coating it with a second uncrosslinked rubber composition for constituting the outer layer 13, and heating and pressurizing them to crosslink the first and second uncrosslinked rubber compositions. The whole is integrated. That is, the inner layer 11 and the intermediate layer 12 are integrated with the progress of the crosslinking of the first uncrosslinked rubber composition, and the intermediate layer 12 and the intermediate layer 12 with the progress of the crosslinking of the first and second uncrosslinked rubber compositions. The outer layer 13 is integrated, and the inner layer 11, the intermediate layer 12, and the outer layer 13 are integrated as a whole.

  According to the fuel hose 10 configured as described above, the inner layer 11 is formed of a mixed composition of a fluororesin and a vinylidene fluoride rubber, and the intermediate layer 12 is formed of a first crosslinked rubber composition. Further, the outer layer 13 is formed of the second crosslinked rubber composition, and the combination thereof provides high adhesion between the inner layer 11 and the intermediate layer 12 and between the intermediate layer 12 and the outer layer 13. The integrity of the inner layer 11, the intermediate layer 12, and the outer layer 13 will be excellent.

  In the present embodiment, the fuel hose 10 has a three-layer structure. However, the fuel hose 10 is not particularly limited thereto, and may further include an outer layer.

(Constituent materials)
The following inner layer materials 1 to 8, intermediate layer materials 1 to 4, and outer layers 1 to 2 were prepared. The respective compositions of the inner layer material 4 and the intermediate layer materials 1 to 4 are also shown in Tables 1 and 2.

<Inner layer material>
-Inner layer material 1-
An ethylene / tetrafluoroethylene copolymer (manufactured by Daikin Industries, Ltd., hereinafter referred to as “ETFE”) and a vinylidene fluoride rubber (manufactured by Daikin Industries, Ltd., hereinafter referred to as “FKM”) are the former / the latter = 70/30. The mixed composition was used as the inner layer material 1.

-Inner layer material 2-
The mixed composition mixed at ETFE / FKM = 80/20 was used as the inner layer material 2.

-Inner layer material 3-
The mixed composition mixed at ETFE / FKM = 90/10 was used as the inner layer material 3.

-Inner layer material 4-
A blend rubber of nitrile rubber and vinyl chloride rubber (manufactured by Nippon Synthetic Rubber Co., Ltd., product number: JSRNV75 NBR / PVC = 70/30) is used as a base rubber. No. 3, 5 parts by mass, 1 part by mass of stearic acid, 1.5 parts by mass of vulcanization accelerator CZ, 1.5 parts by mass of vulcanization accelerator TT, 0.5 parts by mass of sulfur (crosslinking agent), 1 part by mass of anti-aging agent RD, And the uncrosslinked rubber composition kneaded by adding 1 part by mass of the anti-aging agent MB was used as the inner layer material 4.

-Inner layer material 5-
Nylon 11 (PA11) resin (trade name: BESN TL manufactured by ARKEMA) was used as the inner layer material 5.

-Inner layer material 6
Tetrafluoroethylene / hexafluoropropylene / vinylidene fluoride terpolymer (THV) resin (trade name: Dyneon THV500, manufactured by 3M) was used as the inner layer material 6.

-Inner layer material 7-
Polyvinylidene fluoride (PVDF) resin (trade name: KYNAR710 manufactured by ARKEMA) was used as the inner layer material 7.

-Inner layer material 8-
A vinylidene fluoride / hexafluoropropylene copolymer (FKM) rubber (trade name: Daiel G755 manufactured by Daikin Industries, Ltd.) was used as the inner layer material 8.

<Interlayer material>
-Intermediate layer material 1-
Epichlorohydrin / ethylene oxide copolymer rubber (trade name: Epichromer C, manufactured by Daiso Corporation) is used as a base rubber, and 50 parts by mass of FFF carbon black and a plasticizer (di- (butoxy ethoxy. Ethyl) adipate) 10 parts by weight, lubricant sol vitamin monostearate) 1 part by weight, acid acceptor (magnesium oxide) 5 parts by weight, vulcanizing agent (2-mercaptoimidazoline) 1.5 parts by weight, vulcanization retarder ( 4,4'-dithiomorpholine Ouchi Shinsei Chemical Co., Ltd. trade name: Balnock R) 0.5 parts by mass, bisphenol A type epoxy resin (Shell Petrochemical Co., Ltd. trade name: Epicoat 828) 4 parts by mass, anti-aging agent 1 (Nickel dibutyldithiocarbamate) 1 part by mass, anti-aging agent 2 (1,3-bis (dimethylaminopropyl) -2-thiourine Ouchi Shinko Chemical Co., Ltd. trade name: Nocrac NS-10 N) 1 part by mass, and was uncrosslinked rubber composition obtained by kneading the interlayer material 1 by adding 5 parts by weight of calcium carbonate.

-Intermediate layer material 2-
An uncrosslinked rubber composition obtained in the same manner as the intermediate layer material 1 was used as the intermediate layer material 2 except that the product name Zeklon 3100 manufactured by Nippon Zeon Co., Ltd. was used as the epichlorohydrin rubber of the base rubber.

-Intermediate layer material 3-
An uncrosslinked rubber composition obtained in the same manner as the intermediate layer material 1 except that no bisphenol A type epoxy resin was added was used as the intermediate layer material 3.

-Intermediate layer material 4-
An uncrosslinked rubber composition obtained in the same manner as the intermediate layer material 3 was used as the intermediate layer material 4 except that the product name Zeklon 3100 manufactured by Nippon Zeon Co., Ltd. was used as the epichlorohydrin rubber of the base rubber.

<Outer layer material>
-Outer layer material1-
An uncrosslinked rubber composition having the same configuration as that of the inner layer material 4 was used as the outer layer material 1.

-Outer layer material 2-
Thermoplastic olefin (TPO) (trade name: Milastomer 6030B, manufactured by Mitsui Chemicals, Inc.) was used as the outer layer material 2.

(Test evaluation sample)
<Example 1>
Each of the sheet-like inner layer material 1, the intermediate layer material 1, and the outer layer material 1 is laminated in order, and is formed by holding it at 160 ° C. under a condition of 9.8 MPa for 15 minutes and having a thickness of 0.05 mm A sheet-like laminate including an inner layer, an intermediate layer having a thickness of 0.05 mm, and an outer layer having a thickness of 4.90 mm was taken as Example 1.

<Example 2>
A sheet-like laminate obtained in the same manner as in Example 1 except that the inner layer has a thickness of 0.50 mm, the intermediate layer has a thickness of 0.10 mm, and the outer layer has a thickness of 4.40 mm. 2.

<Example 3>
A sheet-like laminate obtained in the same manner as in Example 1 except that the inner layer material 2 was used instead of the inner layer material 1 was designated as Example 3.

<Example 4>
A sheet-like laminate obtained in the same manner as in Example 3 except that the inner layer has a thickness of 0.50 mm, the intermediate layer has a thickness of 0.10 mm, and the outer layer has a thickness of 4.40 mm. It was set to 4.

<Example 5>
A sheet-like laminate obtained in the same manner as in Example 1 except that the inner layer material 3 was used instead of the inner layer material 1 was taken as Example 5.

<Example 6>
A sheet-like laminate obtained in the same manner as in Example 5 except that the inner layer has a thickness of 0.50 mm, the intermediate layer has a thickness of 0.10 mm, and the outer layer has a thickness of 4.40 mm. It was set to 6.

<Example 7>
A sheet-like laminate obtained in the same manner as in Example 1 except that the intermediate layer material 2 was used instead of the intermediate layer material 1 was designated as Example 7.

<Example 8>
A sheet-like laminate obtained in the same manner as in Example 7 except that the inner layer has a thickness of 0.50 mm, the intermediate layer has a thickness of 0.10 mm, and the outer layer has a thickness of 4.40 mm. It was set to 8.

<Example 9>
A sheet-like laminate obtained in the same manner as in Example 1 except that the intermediate layer material 3 was used instead of the intermediate layer material 1 was defined as Example 9.

<Example 10>
A sheet-like laminate obtained in the same manner as in Example 9 except that the inner layer thickness is 0.50 mm, the intermediate layer thickness is 0.10 mm, and the outer layer thickness is 4.40 mm. It was set to 10.

<Example 11>
A sheet-like laminate obtained in the same manner as in Example 1 except that the intermediate layer material 4 was used instead of the intermediate layer material 1 was defined as Example 11.

<Example 12>
A sheet-like laminate obtained in the same manner as in Example 11 except that the inner layer has a thickness of 0.50 mm, the intermediate layer has a thickness of 0.10 mm, and the outer layer has a thickness of 4.40 mm. It was set to 12.

<Comparative Example 1>
A sheet body having a thickness of 0.50 mm formed by holding the sheet-like inner layer material 4 at 160 ° C. under a condition of 9.8 MPa for 15 minutes was defined as Comparative Example 1.

<Comparative example 2>
The sheet-like outer material 1 was held at 160 ° C. under a condition of 9.8 MPa for 15 minutes, but the inner layer material 5 was adhered to one side by electrostatic coating, and then held at 200 ° C. under a condition of 9.8 MPa for 15 minutes. A sheet-like laminate of an inner layer having a thickness of 0.50 mm and an outer layer having a thickness of 4.50 mm was formed as Comparative Example 2.

<Comparative Example 3>
A sheet-like laminate of an inner layer having a thickness of 0.50 mm and an outer layer having a thickness of 4.50 mm, which was formed by simply laminating the sheet-like inner layer material 6 and the outer layer material 2 in this order, was referred to as Comparative Example 3.

<Comparative example 4>
A sheet-like laminate obtained in the same manner as in Comparative Example 2 except that the inner layer material 7 was used instead of the inner layer material 5 was designated as Comparative Example 4.

<Comparative Example 5>
Each of the sheet-like inner layer material 8 and the outer layer material 1 is laminated in order, and the inner layer material is formed by holding it at 160 ° C. for 15 minutes under the condition of 9.8 MPa and the thickness of 4 mm. A sheet-like laminate with an outer layer of 50 mm was designated as Comparative Example 5.

(Test evaluation method)
<Peel adhesion>
The 180 degree peeling test was done about each of Examples 1-13 and Comparative Examples 2-5. However, Comparative Example 3 is non-adhesive.

  Specifically, a strip-shaped test piece is cut out, a cut is made between the inner layer and the outer layer, the inner layer is chucked with one chuck of the Tensilon universal testing machine, and the outer layer is chucked with the other chuck. Peeling was 180 ° at a tensile rate of min. And the peeling adhesive force (N / cm) which remove | divided the force required for peeling at that time by the width | variety of the test piece was computed.

  Moreover, the same 180 degree peeling test was done also about the test piece which made CE10 contact the inner layer for 48 hours on the conditions of 60 degreeC of atmospheric temperature. In addition, if the decrease in the adhesive force after the fuel is brought into contact with the inner layer is large, there is a high possibility that the fuel will scatter from the end through the inner layer and the outer layer.

<Fuel permeability>
About each of Examples 1-13 and Comparative Examples 1-5, the fuel-permeability test was done by the aluminum cup vapor method.

Specifically, CE10 (Fuel C (isooctane and toluene mixed at a volume ratio of 50:50) and ethanol mixed at a volume ratio of 90:10) is placed in an aluminum cup and 25 ml is placed in the opening. The test piece was covered. And after measuring the whole initial mass, it puts in the oven adjusted to 40 degreeC, measures the whole mass every day, and the test which coat | covers the opening part of an aluminum cup for the mass variation per day The fuel permeation rate (g / m ² / day) divided by the area of the piece was calculated. As data, the average value of the fuel permeation rate from the 7th day to the 14th day from the start of measurement of the fuel permeation rate was obtained.

<Flexibility>
About each of Examples 1-13 and Comparative Examples 1-5, the softness | flexibility when a sheet-like test piece was rolled up in the cylinder shape was evaluated in three steps, (double-circle), (circle), and (triangle | delta).

<Ozone resistance>
About each of Examples 1-13 and Comparative Examples 1-5, the ozone degradation test was done according to B method of 4.2.5 of JIS K6330, ie, according to 16 of JIS K6301.

  Specifically, a test piece having a length of 60 mm and a width of 10 mm was cut out and held for 48 hours under conditions of an ozone concentration of 50 ± 5 pphm and an ambient temperature of 40 ° C. in a state of giving 20% elongation. Then, the ozone-degraded test piece is wound around a cylinder, and the surface deterioration state is observed with a magnifying glass. Was rated as x.

(Test evaluation results)
Tables 3 and 4 show the test evaluation results.

<Peel adhesion>
According to the above result, Examples 1-12 which combined inner layer materials 1-3 and intermediate layer materials 1-4, and Comparative Examples 2-5 which used inner layer materials 5-8 and did not provide an intermediate layer. By comparison, it can be seen that the former has higher adhesion between the inner and outer layers than the latter.

  Comparing Example 1 and Example 2 in which the thicknesses of the inner layer and the intermediate layer are different, it can be seen that there is no difference in the adhesion between the inner layer and the outer layer due to the difference in the thickness of the inner layer and the intermediate layer. The same applies to Example 3 and Example 4, Example 5 and Example 6, Example 7 and Example 8, Example 9 and Example 10, and Example 11 and Example 12.

  When Examples 1, 3 and 5 using the inner layer materials 1 to 3 having different ETFE contents are compared, the adhesion between the inner layer and the outer layer is higher in the order of Examples 1, 3 and 5 having the higher ETFE contents. I understand that it is expensive. Similarly, in Examples 2, 4 and 6, it can be seen that the adhesion between the inner layer and the outer layer is higher in the order of Examples 2, 4 and 6 having the higher ETFE content.

  When Examples 1, 7, 9 and 11 using the intermediate layer materials 1 to 4 are compared, Example 1 using the intermediate layer material 1 containing the bisphenol A type epoxy resin does not contain the intermediate layer material. The adhesion between the inner layer and the outer layer is higher than in Example 9 using 3, and similarly, Example 7 using the intermediate layer material 2 is more inner layer than Example 11 using the intermediate layer material 4. It can be seen that the adhesion between the outer layer and the outer layer is high. Further, the adhesion between the inner layer and the outer layer is higher in Example 2 using the intermediate layer material 1 containing the bisphenol A type epoxy resin than in Example 10 using the intermediate layer material 3 not containing it. Similarly, it can be seen that Example 8 using the intermediate layer material 2 has higher adhesion between the inner layer and the outer layer than Example 12 using the intermediate layer material 4.

<Fuel permeability>
Comparing Examples 1 to 12 and Comparative Examples 2 to 5 using the inner layer materials 1 to 3 and 5 to 8 of the fluororesin and Comparative Example 1 using the inner layer material 4 of the nitrile rubber, the former is the latter It can be seen that the fuel permeation rate is significantly lower.

  Comparing Example 1 and Example 2 in which the inner layer and the intermediate layer have different thicknesses, it can be seen that the fuel permeation rate is lower in Example 2 in which the inner layer and the intermediate layer are thicker than in Example 1. The same applies to Example 3 and Example 4, Example 5 and Example 6, Example 7 and Example 8, Example 9 and Example 10, and Example 11 and Example 12.

  When Examples 1, 3 and 5 using the inner layer materials 1 to 3 having different ETFE contents are compared, it can be seen that the fuel permeation rate is higher in the order of Examples 1, 3 and 5 having the higher ETFE contents. Similarly, it can be seen that the fuel permeation rate is higher in the order of Examples 2, 4 and 6 in which the content of ETFE is higher.

  When Examples 1, 7, 9, and 11 using the intermediate layer materials 1 to 4 are compared, it can be seen that there is no difference in fuel permeability due to the difference in the intermediate layer material. The same applies to Examples 2, 8, 10 and 12 using the intermediate layer materials 1 to 4.

<Flexibility and ozone resistance>
In Examples 1 to 12 and Comparative Examples 1 to 5, the flexibility and the ozone resistance are both at a practical level.

  The present invention is useful for a fuel hose and a manufacturing method thereof.

It is sectional drawing of the fuel hose which concerns on embodiment.

Explanation of symbols

10 Fuel hose 11 Inner layer 12 Middle layer 13 Outer layer

Claims (8)

An inner layer formed of a mixed composition of a fluororesin and a vinylidene fluoride rubber;
An intermediate layer provided to cover the inner layer and formed of the first crosslinked rubber composition;
An outer layer provided to cover the intermediate layer and formed of the second crosslinked rubber composition;
Is a fuel hose characterized by being integrally formed. The fuel hose according to claim 1,
A fuel hose wherein the fluororesin is an ethylene / tetrafluoroethylene copolymer resin. The fuel hose according to claim 1 or 2,
A fuel hose, wherein a mixing mass ratio of the fluororesin and the vinylidene fluoride rubber (fluororesin / vinylidene fluoride rubber) is 60/40 to 99/1. The fuel hose according to any one of claims 1 to 3,
A fuel hose wherein the first crosslinked rubber composition forming the intermediate layer is an epichlorohydrin rubber composition. The fuel hose according to claim 4, wherein
A fuel hose wherein the epichlorohydrin rubber composition is an epichlorohydrin / ethylene oxide copolymer rubber composition. The fuel hose according to claim 4 or 5,
A fuel hose characterized in that the first crosslinked rubber composition forming the intermediate layer contains a bisphenol A type epoxy resin. The fuel hose according to any one of claims 1 to 6,
A fuel hose characterized in that the second crosslinked rubber composition forming the outer layer is a rubber composition mainly composed of nitrile rubber.   A tubular body for constituting an inner layer formed of a mixed composition of a fluororesin and a vinylidene fluoride rubber is coated with a first uncrosslinked rubber composition for constituting an intermediate layer, Covering with a second uncrosslinked rubber composition for constituting the outer layer, heating and pressurizing them to crosslink the first and second uncrosslinked rubber compositions, and integrating the whole Manufacturing method of fuel hose.

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