JP2000110971A - Fuel hose and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve gasoline resistance and gasoline permeability resistance with flexibility by arranging a thin film resin layer by thermally melting a powder resin on the outer periphery of a rubber inner tube. SOLUTION: A thin film resin layer 2 is formed by thermally melting a powder resin by almost uniformly coating the outer periphery of a rubber inner tube 1 with the powder resin. A kind of powder resin is not basically limited, but a thermoplastic resin such as a meltable/film formable polyamide resin, polyester resin and fluororesin is desirable, and the polyamide resin is particularly desirable from reasons of reactivity with a decomposition residue of a polysulfide bond and meltability/film formability under a comparatively mild heating condition. Nylon 11 is particularly suitable from a balance between gasoline permeability resistance and flexibility of a fuel hose. A film thickness of the thin film resin layer 2 is desirably 150 μm or less in a thin film resin layer composed of a polyamide resin, and is particularly desirable in about 80 μm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel hose and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a fuel hose used for a fuel pipe of an automobile or the like, NBR / PVC (a blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride) having excellent gasoline resistance and gasoline permeability resistance has been used. A multi-layer hose having an NBR inner layer and a CR (chloroprene rubber) outer layer is well known. However, such a rubber single-layer hose has become unable to sufficiently cope with recent severe gasoline permeation regulations.

[0003] For this reason, for example, fuel hoses have been proposed in which a resin layer such as a fluororubber layer or a polyamide resin is extruded as an inner layer of an NBR / PVC layer. Can be expected to have excellent performance, but in the case of a fluoro rubber layer, it has the disadvantage of being very expensive, and in the case of a resin layer, it has poor adhesion to the rubber outer layer and there is a limit to thinning the resin layer Therefore, there is a problem that the flexibility of the fuel hose is impaired.

On the other hand, Japanese Patent Application Laid-Open No.
-216280, JP-A-8-216281, JP-A-8-224800 and JP-A-8-22
In Japanese Patent No. 4801 and the like, a resin layer obtained by thermally melting a polyamide resin powder is provided on the inner peripheral surface of a rubber layer made of NBR / PVC or the like after a certain adhesive property improving means is applied. It proposes a fuel hose. In the case of these fuel hoses, since a thin film resin layer that is well bonded to the rubber layer can be formed, the above-described problems relating to cost, adhesiveness, and flexibility do not occur.

[0005]

However, among fuel hoses, those which are piped for the purpose of recovering evaporated fuel, such as evaporation hoses and breather hoses, generally have a considerably small diameter (for example, an inner diameter of 20 mm).
mm or less).

Therefore, when the invention disclosed in Japanese Patent Application Laid-Open No. 8-216280 or the like is applied to such a type of fuel hose, certain problems occur. That is, it is technically difficult to apply the resin powder to the small inner diameter portion of the rubber tube to a substantially uniform thickness, and the resin layer on the inner peripheral portion of the rubber tube serves as a sealing surface, so that the joint pipe connection portion is formed. Of the seal becomes sweet.

Therefore, an object of the present invention is to provide a fuel hose free of such a problem.

[0008]

[Means for Solving the Problems] The structure of the first invention of the present application (the invention of claim 1) for solving the above problems is that the inner diameter of the rubber inner tube is formed to be small. A fuel hose according to claim 1, wherein a thin resin layer formed by thermally melting a powder resin is provided on an outer periphery of said rubber inner tube.

(Structure of the Second Invention) The structure of the second invention of the present application (the invention according to claim 2) for solving the above problems is as follows.
In a fuel hose of a system for performing a connection seal with a joint pipe using the elastic force of a rubber inner pipe, the outer circumference of the rubber inner pipe is
It is a fuel hose provided with a thin-film resin layer formed by thermally melting a powder resin.

(Structure of Third Invention) The structure of the third invention of the present application (the invention according to claim 3) for solving the above problems is as follows.
A fuel hose according to the first or second invention, wherein the fuel hose is piped for evaporative fuel.

(Structure of the Fourth Invention) The structure of the fourth invention of the present application (the invention according to claim 4) for solving the above problems is as follows.
The fuel hose according to any one of the first to third inventions, wherein the outer peripheral surface of the rubber inner tube has a shape with irregularities, and the thin film resin layer is provided along the outer peripheral surface shape.

(Structure of Fifth Invention) The structure of the fifth invention of the present application (the invention according to claim 5) for solving the above problems is as follows.
The fuel hose according to any one of the first to fourth inventions, wherein the thin film resin layer is obtained by thermally melting a polyamide resin powder.

(Structure of the Sixth Invention) The structure of the sixth invention of the present application (the invention according to claim 6) for solving the above problems is as follows.
At least a step of forming a rubber inner tube, a step of applying a powder resin to an outer peripheral surface of the formed rubber inner tube, and a step of thermally melting the powder resin to form a film This is a method for manufacturing a hose.

[0014]

(Effects and Effects of the First Invention) In the first invention, even if the inner diameter of the rubber inner tube is small, the powder resin is substantially uniformly applied to the outer periphery and is thermally melted. It is technically easy. Therefore, it is possible to easily provide a low cost and flexible fuel hose having a thin film resin layer on the outer periphery of the rubber inner tube and having excellent gasoline resistance and gasoline permeability resistance.

(Function / Effect of Second Invention) In the second invention, in addition to the function / effect of the first invention, since the thin film resin layer is provided on the outer periphery of the rubber inner tube, the elastic force of the rubber inner tube is utilized. This does not hinder the connection seal with the joint pipe, and the sealing performance is improved by the tightening force of the thin film resin layer.

(Operation and Effect of Third Invention) According to the third invention, an evaporation hose, a breather hose, and the like for evaporative fuel which are flexible and excellent in gasoline resistance can be easily provided at low cost.

(Function / Effect of the Fourth Invention) In the fourth invention, the thin film resin layer formed along the outer peripheral surface shape with the unevenness of the inner rubber tube has elastic elasticity in the radial direction. Therefore, the elastic force of the inner rubber tube and the elastic force of the thin film resin layer act synergistically on the connection seal with the joint tube, and the sealing performance is further improved. The formation of such a thin-film resin layer is technically easy as long as it is formed on the outer peripheral surface of the rubber inner tube.

(Function / Effect of the Fifth Invention) In the fifth invention, since a thin film resin layer is formed by hot-melting a polyamide resin powder, its moldability and gasoline permeation resistance are particularly excellent.

(Function / Effect of Sixth Invention) According to the sixth invention, the fuel hoses of the first to fifth inventions can be easily manufactured at low cost.

[0020]

Next, embodiments of the first invention to the sixth invention will be described. In the following, simply "the present invention"
When it says, it refers to 1st invention-6th invention collectively.

[Fuel Hose] The fuel hose according to the present invention is used for transporting gasoline and other fuels, and for transporting or recovering evaporated fuel, and the type thereof is not limited. It is particularly preferably applied to hoses for various fuel pipes of automobiles and the like, and particularly preferably applied to fuel hoses corresponding to any of the following. A fuel hose in which the inner diameter of the rubber inner tube is formed to be small (for example, the inner diameter is about 20 mm or less). A fuel hose of a type that seals connection with a joint pipe using a connection jig such as an elastic force of a rubber inner pipe and a clamp. A fuel hose that is piped to transport or recover evaporated fuel. For example, a so-called evaporation hose connecting a fuel tank and a canister, or a so-called breather hose attached to a fuel supply pipe.

It is sufficient for the fuel hose to have at least a thin resin layer formed by melting a resin powder at the outer periphery of the inner rubber tube. More preferably.

The shape of the fuel hose is not limited, and may be a straight tube or a fuel hose having a smooth bend or bellows-shaped peripheral surface, such as that found in an automotive filler hose. .

[Rubber inner tube] The rubber inner tube has gasoline resistance,
Using an appropriate rubber material in consideration of gasoline permeation resistance, it is formed into arbitrary inner and outer diameters as needed. NBR / PVC is optimal as the base material constituting the inner rubber tube, but basically any rubber material capable of sulfur vulcanization may be used. For example, acrylonitrile-butadiene rubber (N
BR) and the like can be arbitrarily used.

The inner rubber tube may be formed to have a smooth cylindrical outer peripheral surface, but it is more preferable to form the inner rubber tube into a shape having arbitrary irregularities. In this case, since the thin film resin layer formed along the outer peripheral surface shape is also formed in a thin cylindrical shape with unevenness, the thin film resin layer has elasticity in the radial direction, and the rubber inner tube is formed. The connection seal with the joint pipe utilizing the elastic force of the above is further improved.

As an example, the inner rubber tube 1 shown in FIG. 1 has a shape in which the outer peripheral surface of the radial cross section has corrugated irregularities, and the thin film resin layer 2 has corrugated irregularities along the outer peripheral surface. It is formed in a tubular shape. As another example, as shown in FIG. 2, an inner rubber tube 1 formed in the same manner as the case shown in FIG.
Further, a rubber outer tube 3 is formed on the outer peripheral portion of the thin film resin layer 2.

In the embodiment shown in FIGS. 1 and 2, the form of the irregularities formed on the outer peripheral surface of the rubber inner tube 1 is not limited, but preferably includes irregularities along the radial direction.
In addition, such a concave-convex shape may be provided by the shape of a die at the time of extrusion molding of the rubber inner tube 1 or may be formed on the rubber inner tube extruded into a cylindrical shape by any means.

[Characteristics and Composition of Rubber Inner Tube] In the fuel hose of the present invention, the fuel permeating the rubber inner tube is blocked by the thin resin layer having high gasoline permeation resistance. May accumulate at the interface. Therefore, it is preferable to prevent the separation of the interface by increasing the adhesiveness of the interface. For this purpose, one or more of the following 1) to 3) can be applied.

1) The rubber material of the inner rubber tube used for the deposition and film formation of the powder resin is bonded to its polysulfide bond (-Sx-,
The crosslink density of x ≧ 3) is adjusted so as to be 4 × 10 ⁻⁵ mol / cm ³ or more.

When a rubber is vulcanized with a sulfur-based vulcanization accelerator, a cross-linked form of a monosulfide bond (-S-), a disulfide bond (-SS-) and a polysulfide bond is formed. In rubber products for use, the crosslink density of polysulfide bonds is adjusted as low as possible from the viewpoint of heat resistance. However, in the present invention, when the powder resin is thermally melted to form a film, the polysulfide bond intentionally set at a high crosslinking density is sufficiently thermally decomposed even under mild heating conditions, and the decomposed residue is formed into a thin film. By bonding with the resin molecules of the resin layer, the adhesion between the inner rubber tube and the thin film resin layer is strengthened. In addition, since the heating conditions can be set mildly in this way, the elasticity and flexibility of the hose can be favorably maintained while avoiding excessive hardening of the rubber inner tube.

The crosslink density of these polysulfide bonds can be measured, for example, by the method described in JP-A-8-224800, paragraph [0009].

2) As described above, in order to adjust the crosslinking density of the polysulfide bond to a high value, a thiazole-based vulcanization accelerator such as dibenzothiazyl disulfide or mercapto may be used as a vulcanization accelerator to be added to the base material. It is preferable to use benzothiazole, N-cyclohexyl-2-benzothiazylsulfenamide, or the like. A thiazole vulcanization accelerator may be used in combination with another vulcanization accelerator.

3) Any one or more of carboxyl group-containing NBR, phenolic resin, and epoxy compound are mixed with the base material. By these blending, even if the heating conditions for hot-melting the resin powder are set mildly, the adhesive strength between the thin film resin layer and the rubber inner tube can be sufficiently obtained.

The compounding amount of the NBR containing carboxyl group is suitably 2 to 15 parts by weight based on 100 parts by weight of the base material. When the amount is less than 2 parts by weight, the effect of improving the adhesive strength is small, and exceeds 15 parts by weight. Although the effect of improving the adhesive strength is great, there is a tendency that the set property of the rubber is deteriorated and the sealing property is deteriorated. Here, the carboxyl group-containing NBR is obtained by polymerizing one or more monomers having a carboxyl group such as acrylic acid and methacrylic acid as a third component monomer together with an acrylonitrile monomer and a butadiene monomer. The proportion of the monomer having a carboxyl group is suitably about 1 to 15% by weight. When the amount is less than 1% by weight, the above-mentioned effect of improving the adhesive strength is small, and when the amount exceeds 15% by weight, the effect of improving the adhesive force is large. There is a tendency that the set properties of the rubber are deteriorated and the sealing property is deteriorated.

Examples of the phenolic resin include a pure phenolic resin, a cashew-modified phenolic resin, an alkyl-modified phenolic resin, and the like. These can be used alone or in combination of two or more. The compounding amount of the phenolic resin is suitably 5 parts by weight or less with respect to 100 parts by weight of the base material. When the amount exceeds 5 parts by weight, the effect of improving the adhesive strength is large, but the setting property of the rubber deteriorates. There is a tendency for the sealing performance to deteriorate.

As the epoxy compound, those having an epoxy equivalent of 300 or less are used. If the epoxy equivalent exceeds 300, the set properties of the rubber tend to deteriorate, and the sealing properties tend to deteriorate. The amount of the epoxy compound to be blended is suitably 6 parts by weight or less based on 100 parts by weight of the base material, and if it exceeds 6 parts by weight, the set properties of the rubber also tend to deteriorate, and the sealing property tends to deteriorate. Because. Examples of epoxy compounds include condensates of bisphenol A and epichlorohydrin, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether,
Glycidyl ether type such as resorcin diglycidyl ether, polyethylene diglycidyl ether, polypropylene glycol diglycidyl ether, and polyglycidyl ether type such as glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, and diglycerol polyglycidyl ether; Glycidyl ester type such as adipic acid diglycidyl ester and the like can be mentioned.

[Thin Film Resin Layer] The thin film resin layer is formed by applying a powder resin substantially uniformly on the outer periphery of the rubber inner tube and thermally melting the resin. The type of the powder resin to form the thin film resin layer is not basically limited, but a thermoplastic resin such as a meltable / film-forming polyamide resin, a polyester resin, and a fluorine-based resin is preferable. Polyamide resins are preferred because of their reactivity with decomposed residues and their ability to melt and form films under relatively mild heating conditions.

Among the polyamide resins, nylon 6, nylon 11, nylon 12, nylon 6,10, nylon 6,12, nylon 6/66 copolymer, nylon 6/66
Twelve copolymers and the like are preferably exemplified, but nylon 11 is particularly preferred from the balance between gasoline permeation resistance and fuel hose flexibility. It is also possible to use a resin obtained by blending a plasticizer or an elastomer with a polyamide resin, or a material obtained by copolymerizing a polyamide resin with polyether or polyester.

The thickness of the thin resin layer is determined by weighing the degree of gasoline permeation resistance and the effect on the flexibility of the fuel hose, and cannot be uniformly limited. In the case of a thin resin layer made of a resin, the thickness is preferably 150 μm or less, and
It is preferably about μm or less.

[Manufacture of Fuel Hose] In the method of manufacturing a fuel hose according to the sixth aspect of the present invention, at least a step of forming a rubber inner tube, and applying a powder resin to an outer peripheral surface of the formed rubber inner tube. And a step of thermally melting the powder resin to form a film. When a rubber outer tube is provided on the outer periphery of the thin film resin layer, a rubber outer tube forming step is added according to a conventional method.

The molding conditions in the step of molding the rubber inner tube depend on the shape and thickness of the rubber inner tube, but usually, in the case of injection molding, a molding temperature of 160 ° C. and a molding time of 5 to 10 minutes. The setting of the degree is preferable. In the case of extrusion molding, it is appropriate that the inner tube is heated in a steam can at 150 ° C. for 10 to 30 minutes after extrusion.

In the step of adhering the powder resin to the outer peripheral surface of the rubber inner tube, a resin powder such as a polyamide resin is charged to a positive charge or a negative charge, and is applied to the outer peripheral surface of the rubber inner tube by electrostatic attraction. The electrostatic coating method to be applied is preferable, but various coating methods such as a powder flowing immersion coating method, a spray spraying method, an outer surface liquid paint immersion method, and an electrodeposition coating method can be used.

The step of forming a film by thermally melting the powder resin may be performed by any heating means. For example, an oven can be used. The heating conditions are not limited.However, in order to avoid the hardening of the rubber material of the rubber inner tube and maintain the flexibility of the hose, it is preferable that the heating is performed under mild conditions as much as possible, and the resin thin film layer and the rubber inner tube are heated. Good adhesion is desired. For this purpose, for example, when the resin powder is made of a polyamide resin, the heating temperature is 200 to 220 ° C. and the heating time is 2 hours.
It is preferable to set a relatively mild condition of about 0 to 40 minutes.

In the case of applying the adhesiveness improving means of 1) to 3) described in the above section "Characteristics and composition of inner rubber tube", the purpose can be achieved by heating under milder conditions. Heating temperature is 200 ~ 220 ° C, heating time is 10 ~
It is preferable to set the condition to about 30 minutes.

[0045]

EXAMPLES ( Production of rubber inner tube ) First, Table 1 at the end
-Rubber compositions shown in columns A to E in Table 4 were prepared, extruded at 160 ° C. for 5 minutes into a tube having a cross-sectional shape shown as rubber inner tube 1 in FIG. 1, and inserted into a mandrel. The primary vulcanization was performed at 150 ° C. for 20 minutes, and the inner diameter was 9.5 mm, the thickness (the thickness from the inner peripheral surface to the outer peripheral surface bottom of the tube wall) was 3.5 mm, and the length was 200 mm.
The rubber inner tubes A to E of a curved tubular shape shown in FIG.

The crosslink densities of these inner rubber tubes A to E due to polysulfide bonds were measured according to the above-described measurement method, and the results are shown in the corresponding columns in Table 5 at the end.

( Formation of Fuel Hose ) Next, various polyamide resin powders shown in Table 2 having a thickness of 0.2 mm were applied to the outer peripheral surfaces of these rubber inner tubes A to E in accordance with the conditions shown in Table 2.
mm. This electrostatic coating is 60 kV / 10
The charge was performed by charging the polyamide resin powder to a positive charge by μA corona discharge. Then, the thin film resin layer was formed by heat-treating the electrostatically coated product according to the heating conditions shown in Table 2, and the fuel hoses according to Examples 1 to 7 were obtained.

( Evaluation of Fuel Hose ) 1) Peeling strength: A flat portion (straight tubular portion) of the fuel hose according to each of these examples was cut into a ring shape with a width of 25 mm in the axial direction of the hose, and then cut in the axial direction. It was cut open, and the peeling force in the circumferential direction between the inner rubber tube and the thin film resin layer was measured. The results are shown in Table 5 as "outer / inner layer peel strength (N / mm)".

2) Change in rubber hardness: The rubber hardness (JIS A) of the inner rubber tubes A and B of the fuel hose according to each of the above embodiments before the heat treatment under the above heating conditions was measured in advance, and after the heat treatment. Was also measured, and its change value was determined. The results are shown in Table 5 in "Rubber hardness change (J
IS A) ".

3) Permanent compression strain: 100 ° C. according to JIS K6301 for the fuel hose according to each of the above embodiments.
The permanent compression set (%) after × 22 hours was measured. The results are shown in Table 5 as "permanent compression strain (%)".

4) Flexibility: The load (N) was measured when one end of the fuel hose according to each of the above embodiments was fixed and the other end was displaced 200 mm in a direction perpendicular to the hose axis direction.
The case where the load is 700 N or less is indicated by “◎”, 70
A case of more than 0N and 900N or less was evaluated as “評 価”, and is shown in the section of “Hose Flexibility” in Table 5.

5) Gasoline permeation resistance: “fuel C” was placed inside the fuel hose according to each of the above embodiments as a pretreatment.
(2,2,4-trimethylpentane (isooctane) 5
(0% / toluene 50%) was sealed and left at 40 ° C. for 168 hours and then removed. After that, fuel C was sealed again and left at 40 ° C., and every 24 hours, a total of 7
The amount of weight loss of the fuel C sealed up to 2 hours was measured. The case where the weight loss amount was 0.1 g / book / day or less was evaluated as “◎”, and the case where the weight loss amount exceeded 0.1 g / book / day and was 0.2 g / book / day or less was evaluated as “○”. No. 5 in the section of “resistance to gasoline permeation”.

6) Sealability, etc .: Example 8 shown in Table 6
9. Fuel hoses according to Comparative Examples 1 and 2 were produced, and sealing properties and the like were evaluated.

That is, Examples 8 and 9 and Comparative Examples 1 and 2 were basically configured according to Example 2 in Table 5, and Example 8 was the outer peripheral surface of the rubber inner tube. Example 9 is a fuel hose having the same configuration as that of Example 2 except that the thin film resin layer has a cylindrical surface with no irregularities and the thin film resin layer also has a shape conforming thereto. Is different from Example 2 only in that it was formed on the inner peripheral surface of the rubber tube, and Comparative Example 2 was different from Example 2 only in that no thin film resin layer was formed.

The outer layer / inner layer peel strength and the change in rubber hardness were evaluated for Comparative Example 1.
The heat treatment for forming the thin film resin layer at 0 ° C. × 20 minutes resulted in a breaking strength of 0.6 N / mm, and the heat treatment at 210 ° C. × 25 minutes caused rubber breakage. 21 for the latter
In the heat treatment for forming the thin film resin layer at 0 ° C. × 25 minutes, the change in rubber hardness was +8 or more.

As a method for evaluating the sealing performance, the fuel hose according to each of these examples was air-tightly closed at one end opening, and inserted a pipe having an outer diameter of 10 mm from the other end opening and having a bulged end. After being immersed in a container filled with water in this state, nitrogen gas was pressurized from the pipe, and gas leakage at the pipe insertion portion was measured. Further, the insertion force required for inserting the pipe was also evaluated as “insertion property”.

The results of these evaluations are shown in Table 6. In the sealing performance evaluation column, “○” indicates that the nitrogen gas pressure was 0.1 MPa.
Indicates that there was no gas leakage, and “x” indicates that there was gas leakage at a nitrogen gas pressure of 0.1 MPa. On the other hand, in the evaluation column for insertability, “◎” indicates less than 50 N, “○” indicates 50 N to 100 N, and “×” indicates more than 100 N.

The fuel hose according to each of the above examples is
The same flexibility evaluation as in 4) and the same gasoline permeation resistance evaluation as in 5) were also performed, and the evaluation results are shown in Table 6 according to the same evaluation criteria as above.

(Evaluation Results) From the above results, it was found that the outer layer and the inner layer (that is, the rubber inner tube and the thin film resin layer) were firmly bonded to each other even if the heat treatment time was short. , Found to be of high quality.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

[Table 3]

[0063]

[Table 4]

[0064]

[Table 5]

[0065]

[Table 6]

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the present invention.

FIG. 3 is a perspective view showing an appearance of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rubber inner tube 2 Thin film resin layer 3 Rubber outer tube

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 3H111 AA02 BA11 BA15 CA53 CB03 CB04 CB08 CB14 CB23 DA09 DA14 DB08 EA16 4F100 AK01B AK15 AK27 AK29 AK46B AK73 AL01 AN02A BA02 BA03 BA06 DD01 EH462 EJ422 JEJBJB4A32J02AJB4A AD05 AD12 AD32 AG03 AG08 AH17 WA14 WA34 WA58 WA73 WA86 WA90 WB02 WB18 WB22 WF24 WK03

Claims (6)

[Claims] 1. A fuel hose in which an inner diameter of a rubber inner tube is formed to be small, wherein a thin film resin layer formed by thermally melting a powder resin is provided on an outer periphery of the rubber inner tube. hose. 2. A fuel hose of a type in which a connection seal with a joint pipe is performed by utilizing an elastic force of a rubber inner pipe, wherein a thin film resin layer formed by thermally melting a powder resin is formed on the outer circumference of the rubber inner pipe. A fuel hose, which is provided. 3. The fuel hose according to claim 1, wherein the fuel hose is provided for evaporative fuel. 4. The rubber inner tube according to claim 1, wherein the outer peripheral surface of the inner rubber tube has a shape with irregularities, and the thin film resin layer is provided along the outer peripheral surface shape. Fuel hose as described. 5. The fuel hose according to claim 1, wherein the thin-film resin layer is formed by thermally melting a polyamide resin powder. 6. At least a step of forming an inner rubber tube, a step of applying a powder resin to an outer peripheral surface of the formed inner rubber tube, and a step of thermally melting the powder resin to form a film. A method for manufacturing a fuel hose, comprising: