JP2926646B2 - Hose for automotive fuel piping - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel hose for automobile fuel lines.

[0002]

2. Description of the Related Art Conventionally, fuel pipe hoses used in automobiles or the like or used for connecting fuel pipes have various materials and various structures obtained using the same. in use. For example, a hose composed of a single layer of a polyamide-based resin and a hose having a reinforcing layer formed by braiding a wire around an outer periphery of a fluorine-based resin layer are known.

[0003]

The hose composed of a single layer of the polyamide resin has resistance to gasoline in which peroxide is generated by high temperature (hereinafter abbreviated as "sour gasoline resistance") and gasoline permeation resistance (alcohol). (Including mixed gasoline), resistance to abrasion due to contact with other hoses during piping (hereinafter abbreviated as "interference resistance"), and resistance to physical impacts such as stone jumps during driving (hereinafter abbreviated as "impact resistance") ). Furthermore, in the above-mentioned hose of a single layer of polyamide resin, static electricity is generated due to friction between a fuel liquid such as gasoline and the inner wall of the hose, and the inner wall of the hose is charged. When the voltage exceeds a certain level, sparks occur between the hose and metal parts such as the vehicle body, and sparks may cause holes in the hose or the spark may ignite the fuel. doing.

On the other hand, a hose having a reinforcing layer formed by braiding a wire on the outer periphery of the above-mentioned fluororesin layer,
The fluororesin layer has sour gasoline resistance and gasoline permeability resistance, and has a good interference resistance and impact resistance because a reinforcing layer is formed on the outer periphery by braiding a wire. . However, the hose whose innermost layer is made of a fluorine-based resin has a problem of fire resistance as in the case of the hose made of a single layer of the polyamide-based resin.

The present invention has been made in view of the above circumstances, and has been developed to provide a fuel hose for automobile fuel piping which is excellent in sour gasoline resistance, gasoline permeation resistance, interference resistance, impact resistance as well as ignition resistance. Its purpose is to provide.

[0006]

In order to achieve the above object, an automotive fuel pipe hose according to the present invention comprises: an innermost layer made of a fluororesin; an intermediate layer formed outside the innermost layer; An automotive fuel piping hose having an outer layer formed outside an intermediate layer, wherein a conductive agent is dispersed in an innermost layer in contact with fuel, and the innermost layer is made of poly
Vinylidene fluoride, polychlorotrifluoroethyl
Copolymerization of styrene, ethylene and chlorotrifluoroethylene
Copolymer, copolymer of ethylene and tetrafluoroethylene,
Xafluoropropylene and tetrafluoroethylene
Polymers, fluorinated alkoxyethylene resins and polyteto
At least selected from the group consisting of lafluoroethylene
It is formed of one fluorine-based resin, and the intermediate layer is formed of a polyamide-based resin or a polyester-based resin.

[0007]

In other words, the inventors of the present invention have repeatedly studied on means for preventing charging of the inner wall of the hose, which is a cause of sparks in the hose for automobile fuel piping, and as a result, the innermost layer of the hose in contact with the fuel is dispersed with the conductive agent. When formed with a specific fluorocarbon resin, the static electricity generated by friction between the fuel and the inner wall of the hose always escapes from both ends of the hose, so the inner wall of the hose is not charged, and as a result, sparks due to static electricity do not occur. Heading, this invention was reached.

Next, the present invention will be described in detail.

A hose for an automotive fuel pipe according to the present invention includes an innermost layer made of a fluororesin, an intermediate layer formed outside the innermost layer, and an outer layer formed outside the intermediate layer. Wherein the conductive agent is dispersed in the innermost layer in contact with the fuel, and the innermost layer is a specific fluorine-based resin.
The intermediate layer is formed of a polyamide resin or a polyester resin. For example, the innermost layer formed of a specific fluorine-based resin imparted with conductivity, the outer periphery thereof is formed of an intermediate layer formed of a polyamide resin or a polyester-based resin, and the outer periphery of the intermediate layer is formed of a rubber elastic material. And a fuel hose for an automobile fuel pipe composed of three outer layers.

The above-mentioned specific fluororesin having conductivity is obtained by, for example, dispersing a conductive agent, and is set so that the volume resistivity is 10 ¹⁰ Ω · cm or less. Examples of the specific fluorine-based resin include polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (CTFE), a copolymer of ethylene and chlorotrifluoroethylene (ECTFE), and a copolymer of ethylene and tetrafluoroethylene ( ETFE), a copolymer of hexafluoropropylene and tetrafluoroethylene (F
EP), fluorinated alkoxyethylene resin (PFA), and polytetrafluoroethylene (PTFE) .
Examples of the conductive agent include carbon black and fine stainless fibers.

[0011] As material for the formation of the intermediate layer, positive Riami <br/> de-based resin or polyester resin. Examples of the polyamide resin include, but are not particularly limited to, aliphatic resins and aromatic resins, and conventionally known resins.
Lactam polymer, diamine and dicarboxylic acid condensate,
Examples include amino acid polymers, copolymers and blends thereof. Specifically, nylon 6, nylon 11, nylon 12, nylon 610, nylon 61
2, a blend of nylon 11 or nylon 12 and nylon 66 is preferably used.

The polyester resin is formed by a conventionally known method, that is, condensation polymerization of a polyhydric alcohol and a polybasic acid. Usually, it is obtained by condensation polymerization of a diol and a dicarboxylic acid.

The above diols include ethylene glycol, propylene glycol, 1,4-butanediol,
Neopentyl glycol, cyclohexanediol, xylylene glycol, hexahydroxyrylene glycol, bis (4-β-hydroxyethoxyphenyl) sulfone and the like can be mentioned.

The dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4-diphenylene ether dicarboxylic acid, malonic acid, and succinic acid. ,
Glutaric acid, adipic acid, sebacic acid, undecandioic acid, dodecandioic acid, tridecandioic acid, tetradecandioic acid, hexadecandioic acid, hexadecenedioic acid, octadecandioic acid, octadecenedioic acid, eicosaneiodic acid, eicosenedioic acid, 1 And aliphatic dicarboxylic acids such as 10-dodecanedicarboxylic acid.

Among them, it is preferable to use polybutylene terephthalate, which is a condensation polymer of 1,4-butanediol and terephthalic acid.

Materials for forming the outer layer include ECO (copolymer of epichlorohydrin and ethylene oxide), CSM (chlorosulfonated polyethylene rubber),
Rubbery chlorinated polyethylene (CPE), acrylic rubber (ACM), chloroprene rubber (CR), mixture of acrylonitrile-butadiene copolymer rubber (NBR) and vinyl chloride resin (PVC), EPDM (ethylene-propylene-diene copolymer) Unified rubber), isobutylene-isoprene rubber (IIR), halogenated butyl rubber, thermoplastic rubber, and other rubber elastic materials. Examples of the thermoplastic rubber include a mixture of a polypropylene-ethylene propylene copolymer and polypropylene.

The automotive fuel pipe hose of the present invention can be manufactured by using the above-described raw materials, for example, as follows. First, a conductive agent is blended with a specific fluorine-based resin and mixed. Next, the above-mentioned specific fluorine-based resin is extruded onto a mandrel from an extruder to obtain an innermost tubular body. Next, an intermediate layer is formed by extruding a polyamide resin or a polyester resin on the outer peripheral surface of the innermost tubular body. Then, on the outer peripheral surface of the intermediate layer, an outer layer is formed by extruding a rubber elastic material, and then integrated by heat vulcanization to extract a mandrel,
A three-layer automotive fuel pipe hose can be manufactured. Note that the above mandrel may not be used. Further, the above three layers may be extruded at the same time, or the outermost layer formed by simultaneously extruding the innermost layer and the intermediate layer may be separately formed on the outer peripheral surface by a known method. The vulcanization conditions in this case are usually at a temperature of 150
１６０160 ° C., time 30３０60 minutes. In the case where a thermoplastic rubber is used as the rubber elastic material, vulcanization may not be performed. The amount of the conductive agent is
It is preferred that the volume resistivity is set to be equal to or less than 10 ¹⁰ Omega · cm as described above, the particular fluororesin 10
3 to 2 parts by weight of a conductive agent with respect to 0 parts by weight
It is preferable to set to 5 parts. More preferably, 5
-20 parts.

FIG. 1 shows the hose for an automobile fuel pipe thus obtained. In the figure, 1 is an innermost layer made of a specific fluorine-based resin having a volume resistivity of 10 ¹⁰ Ω · cm or less in which a conductive agent is dispersed, 2 is an intermediate layer made of a polyamide-based resin or polyester-based resin, and 3 is a rubber elastic material. Is shown. In the hose for an automotive fuel pipe of the present invention, the thickness of each layer is such that the innermost layer 1 has a thickness of 50 μm.
m to 0.5 mm, the intermediate layer 2 is 0.6 to 1.2 m
m and the outer layer 3 is preferably set within a range of 0.5 to 5 mm. Particularly preferably, the innermost layer 1
Is 0.2 ± 0.1 mm, and the intermediate layer 2 is 0.8 ± 0.2 m
m, the outer layer 3 is 2 ± 1 mm. As described above, by reducing the thickness of the innermost layer 1 formed using an expensive fluorine-based resin, the cost can be reduced. Moreover,
Even if the thickness of the innermost layer 1 is made thin, high strength can be imparted by the intermediate layer 2 made of a polyamide resin or polyester resin and the outer layer 3 made of a rubber elastic material.

By using a specific fluorine resin for the innermost layer 1, the hose for an automobile fuel pipe obtained in this manner can have gasoline permeation resistance and sour gasoline resistance. By providing the intermediate layer 2 and the outer layer 3 and using the above forming materials for each, the strength of the entire hose is improved, and it is possible to provide interference resistance and impact resistance. By taking the above, the innermost layer 1 formed of an expensive fluororesin can be made thinner, and the cost can be reduced. Furthermore, such a three-layer structure has a simple configuration, does not require a complicated process, and realizes further cost reduction.

Further, as another configuration of the automotive fuel pipe hose of the present invention, as shown in FIG. 2, an innermost layer 1 formed of the specific fluorine-based resin and a polyamide-based resin or One in which an adhesive layer 4 is formed between the adhesive layer 4 and the intermediate layer 2 formed of a polyester-based resin is exemplified. By forming the adhesive layer 4 in this manner, the adhesion between the innermost layer 1 and the intermediate layer 2 is improved. Examples of the material for forming the adhesive layer include a fluorine-based resin, a polyamide-based resin, and a blended material of a fluorine-based resin and a polyamide-based resin. And the said adhesive layer 4 generally
After forming the innermost layer 1, it is formed by applying the adhesive layer forming material. Alternatively, it can be formed by simultaneously extruding the innermost layer 1, the adhesive layer 4, and the intermediate layer 2.

Further, as another constitution of the automotive fuel piping hose of the present invention, as shown in FIG. 3, a polyamide resin or a polyester resin is used to improve the strength of the obtained automotive fuel piping hose. A fiber reinforced layer 5 made of a braid of reinforcing yarn is formed between an intermediate layer 2 to be formed and an outer layer 3 made of a rubber elastic material. The fiber reinforcing layer 5 is formed by braiding or spiral knitting of a yarn mainly composed of synthetic fibers such as nylon fibers, polyester fibers, and aramid fibers, and natural fibers such as cotton fibers. Further, as another configuration of the automotive fuel pipe hose of the present invention, between the innermost layer and the intermediate layer,
One in which an inner layer made of a fluorine-based resin is formed is exemplified. In addition, it is also possible to further provide the adhesive layer between the inner layer made of the fluorine-based resin and the intermediate layer.

Then, as shown in FIG.
An adhesive layer 4 is provided between the intermediate layer 2 and the intermediate layer 2, and the fiber reinforcing layer 5 is provided between the intermediate layer 2 and the outer layer 3 made of a rubber elastic material. The forming material and layer forming method for the adhesive layer 4 and the fiber reinforcing layer 5 are the same as described above.

The innermost layer 1 is formed by forming the adhesive layer 4.
In addition to improving the adhesion between the inner layer 1 and the inner layer 2, for example, after forming the innermost layer 1, the outer peripheral surface of the innermost layer 1 may be subjected to an adhesive treatment. Examples of the bonding treatment include a flame treatment, a corona treatment, a sputtering treatment, and a Na treatment for removing fluorine to activate the surface.

[0024]

As described above, the automotive fuel pipe hose of the present invention has the innermost layer in contact with the fuel formed of a specific fluorine resin in which a conductive agent is dispersed. For this reason, static electricity generated by friction between the fuel liquid such as gasoline and the inner wall of the hose always escapes from both ends of the hose, and the inner wall of the hose is not charged. Therefore, the hose for automotive fuel piping of the present invention is excellent in ignition resistance.

Next, examples will be described together with comparative examples.

[0026]

Examples 1 to 3 First, carbon black was used as a conductive agent and compounded in a fluorine-based resin in the compounding amounts shown in Tables 1 and 2 below. Next, according to the materials shown in Tables 1 and 2 below,
According to the above-mentioned production method, a desired three-layer structure automotive fuel pipe hose (inner diameter: 6 mm) was produced.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

Embodiment 6 An adhesive layer was formed between the innermost layer and the intermediate layer by a conventionally known method using an adhesive made of a mixture of a fluorine resin (PVDF) and nylon. Other than that, the hose for automobile fuel piping (inner diameter 6 mm) of the structure shown in FIG. 2 was produced in the same manner as in Example 1.

[0030]

Example 7 A fiber reinforcing layer was formed between an intermediate layer and an outer layer by spiral knitting using nylon yarn. Except for this, a vehicle fuel pipe hose (inner diameter 6 mm) having the structure shown in FIG. 3 was produced in the same manner as in Example 1.

[0031]

Embodiment 8 Between an innermost layer and an intermediate layer, an adhesive layer made of a mixture of a fluororesin (PVDF) and nylon is used to form an adhesive layer by a conventionally known method, and an intermediate layer and an outer layer. Then, a fiber reinforcing layer was formed by spiral knitting using nylon yarn. Otherwise, the vehicle fuel pipe hose (inner diameter 6) having the structure shown in FIG.
mm).

[0032]

Comparative Example 1 Extrusion hoses were prepared from the materials shown in Table 3 below using an extruder.

[0033]

Comparative Example 2 The materials shown in Table 3 below were extruded with an extruder to form an innermost layer, and a reinforcing layer formed by braiding a wire around the outermost layer was formed by a conventionally known method. Thus, a hose was obtained.

[0034]

[Table 3]

The thus obtained hoses of Examples 1 to 8 and Comparative Examples 1 and 2 were measured and evaluated for burst pressure, gasoline resistance, sour gasoline resistance, and ignition resistance. The results are shown in Tables 4 to 6 below. The above characteristics were measured according to the following evaluation methods.

[Burst Pressure] Continuous pressurization (water pressure) was performed until the hose burst, and the maximum pressure until the hose burst or leak due to pinholes was measured.

[Gasoline Permeation Resistance] A test gasoline, a test gasoline and methanol
2 of mixed gasoline mixed at a ratio of 0:50 (volume ratio)
Prepared the kind. These are sealed in each hose and left at a temperature of 40 ° C. to reduce the weight loss (g / g).
m ² · day) was measured. On the other hand, the inner diameter of the hose was the same as that of the hoses of the examples and the comparative examples, and the innermost layer was made of fluoro rubber (F
KM), the intermediate layer is ECO, and an ECO
The same measurement as above was performed using a conventional hose in which an outer layer made of was formed and a reinforcing layer made of reinforcing yarn was formed between the intermediate layer and the outer layer. The measured value of the conventional hose was set to 1, and the gasoline permeation resistance of the hoses of the above-described example and comparative examples was displayed based on the measured value.

[Sour gasoline resistance] Sour gasoline was circulated in the hose, and abnormalities such as cracks generated on the inner surface of the hose were confirmed. Conditions are temperature 4
The temperature was 0 to 60 ° C., and the circulation pressure was 2.5 kgf / cm ² . As a result, those for which no abnormality was confirmed at all ◎,
も の indicates that almost no abnormality was confirmed, △ indicates slight abnormality, and × indicates abnormality.

[Electrical Resistance] According to JIS (K-6911), volume resistivity (Ω · c)
m) was measured.

[Ignition Resistance] A charge of 30 to 50 kV was applied to the hose, a metal needle was brought close to the hose, and a spark phenomenon was confirmed.

[0041]

[Table 4]

[0042]

[Table 5]

[0043]

[Table 6]

From the results in Table 6 above, it can be seen that the comparative example was inferior in ignition resistance. On the other hand, from the above Tables 4 and 5, all of the products of the present invention have excellent performance in gasoline permeation resistance and sour gasoline resistance, and have high strength, so that they are resistant to interference. It turns out that it is excellent also in the property and impact resistance. Further, since the innermost layer of the hose is formed of a specific fluorine-based resin having conductivity of not more than 10 ¹⁰ Ω · cm, it has excellent fire resistance. In addition, even if the thickness of the innermost layer of the fluorine-based resin is reduced, it has the above-mentioned good performance, and the amount of expensive fluorine-based resin used can be suppressed, and the cost can be reduced. Becomes

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of an embodiment of an automotive fuel pipe hose of the present invention.

FIG. 2 is a sectional view showing the configuration of another embodiment of the automotive fuel hose according to the present invention.

FIG. 3 is a cross-sectional view showing a configuration of still another embodiment of the automotive fuel pipe hose of the present invention.

FIG. 4 is a cross-sectional view showing the configuration of another embodiment of the automotive fuel pipe hose of the present invention.

[Explanation of symbols]

 1 innermost layer 2 middle layer 3 outer layer

Continuation of the front page (56) References JP-A-63-92888 (JP, A) JP-A-2-85591 (JP, A) JP-A-57-1889 (JP, A) Jpn. , U) Japanese Utility Model 1-91183 (JP, U) Japanese Utility Model 63-75684 (JP, U) Japanese Utility Model 60-133286 (JP, U)

Claims (2)

(57) [Claims] An automotive fuel pipe hose comprising: an innermost layer made of a fluororesin; an intermediate layer formed outside the innermost layer; and an outer layer formed outside the intermediate layer. The conductive agent is dispersed in the innermost layer in contact with the fuel,
And the innermost layer is made of polyvinylidene fluoride,
Lichlorotrifluoroethylene, ethylene and chlorotri
Fluoroethylene copolymer, ethylene and tetrafluoro
Hexafluoropropylene and polyethylene copolymer
Trafluoroethylene copolymer, fluorinated alkoxy
Consists of Tylene resin and polytetrafluoroethylene
Formed from at least one fluororesin selected from the group
Is, automobile fuel piping hose, characterized in that the intermediate layer is formed from a polyamide resin or a polyester resin. 2. The hose for an automobile fuel pipe according to claim 1, wherein an adhesive layer is formed between the innermost layer and the intermediate layer.