JP2003106231A - Fuel canister connection member, method of manufacturing the same, and fuel canister - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive fuel canister connection member capable of achieving both of the improvement of fuel-proof permeability and joining strength, and to provide its manufacturing method and the fuel canister. SOLUTION: This fuel canister connection member can be joined to the fuel canister, is made out of resin, has the cylindrical shape and is provided with a carbon thin film of a thickness of 0.05-5 μm on a part excluding a joining part. The carbon thin film has a atomic ratio of carbon:hydrogen = 3:7 through 8:2. A coated face is exposed to plasma such as fluorine-containing gas, hydrogen gas and oxygen gas, and then the carbon thin film is formed to be used as the fuel canister connection member. The carbon thin film is formed by a plasma CVD method. A modulating process for reducing the plasma intensity is performed at least once for 10-120 seconds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel container connecting member, a method of manufacturing the same, and a fuel container.
The present invention relates to a fuel container connecting member for connecting a fuel transportation means such as a fuel tube and a fuel container such as a fuel tank or a canister, a manufacturing method thereof, and a fuel container.

[0002]

2. Description of the Related Art Conventionally, resin-made fuel containers, for example, resin-made fuel tanks, are
High-density polyethylene (HDPE) is the main material, and it is generally manufactured by blow molding. Further, since it suppresses fuel permeation, recently, ethylene-vinyl alcohol copolymer or nylon is used as a barrier layer and an adhesive layer. A multi-layered structure such as 3 types of 5 layers which is adhered to HDPE via is common.

Further, since the connecting member attached to the resin fuel container is bonded to the fuel container by joining using a hot plate or the like, it is generally made of the same resin as the fuel container. . However, as mentioned above, H
Since the connecting member made of DPE has poor fuel permeation resistance, it is required to improve the fuel permeation resistance of the connecting member. In particular, in the future where fuel permeation regulations will become more stringent, high fuel permeation resistance is also required for the connecting members installed in the fuel container.

[0004]

However, the performance strongly demanded of the connecting member is the joint strength with the resin fuel container, and if a material other than HDPE is used, the joint strength tends to be lowered. Although a method of maintaining the joint strength with various structures is conceivable, a method for achieving both the joint strength and the fuel permeation resistance performance has not yet been developed for the current HDPE connecting members.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to improve fuel permeation resistance, achieve compatibility with joint strength, and be inexpensive. A fuel container connecting member, a method for manufacturing the same, and a fuel container.

[0006]

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by providing a carbon thin film with a predetermined film thickness. The present invention has been completed.

That is, the fuel container connecting member of the present invention is a resin-made and tubular fuel container connecting member capable of being joined to a resin fuel container through a joint portion, and a membrane other than the joint portion. A carbon thin film having a thickness of 0.05 to 5 μm is provided.

In a preferred embodiment of the fuel container connecting member of the present invention, the carbon thin film contains carbon atoms and hydrogen atoms, and the atomic ratio is carbon: hydrogen = 3: 7 to 8: 2. It is characterized by

Further, the method for producing a fuel container connecting member of the present invention is a method for producing the above fuel container connecting member, wherein the film-forming surface is selected from the group consisting of fluorine-containing gas, hydrogen gas and oxygen gas. It is characterized in that the carbon thin film is formed after being exposed to the plasma of at least one selected gas.

Furthermore, a preferred embodiment of the method for producing a fuel container connecting member of the present invention is characterized in that the carbon thin film is formed by a plasma CVD method.

Another preferred embodiment of the method for producing a fuel container connecting member of the present invention is that when the carbon thin film is formed, the average plasma intensity during film formation is at least once and for 10 to 120 seconds. It is characterized in that a modulation process for reducing the intensity to ½ or less is performed.

Further, the fuel container of the present invention is characterized by including the above-mentioned fuel container connecting member.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The fuel container connecting member of the present invention will be described in detail below. Such a fuel container connecting member is a member which is made of resin and has a tubular shape, and which can be joined to the resin fuel container through a joining portion. In addition, a carbon thin film having a film thickness of 0.05 to 5 μm is provided in addition to the bonded portion. By setting the film thickness of the carbon thin film within this range, the fuel container connecting member exhibits fuel permeation resistance, and the durability against friction caused by interference with other parts is improved. Also, the connecting member of the present invention can be manufactured using conventional materials and mold structures. That is, the fuel permeation resistance can be improved only by manufacturing the connecting member by the same manufacturing method as that used so far and only by surface-treating the obtained connecting member. The thickness of the resin layer that constitutes the fuel container connecting member is typically 1
~ 5 mm. Further, the fuel container connecting member is installed in the fuel container in order to supply the fuel from the fuel container to other parts via pipes or tubes such as a fuel cut valve, a filler neck valve, and a vent tube. To be done.

Further, as the thickness of the carbon thin film becomes thicker, in other words, as the film forming time becomes longer, the fuel permeation resistance performance improves. However, when the film thickness is constant, cracks are likely to occur, and it is difficult to improve the fuel permeation resistance in proportion to the film thickness. From this, the film thickness is 5 μm
The following is preferable. The “carbon thin film” is a thin film composed of carbon atoms (C) and other atoms, and its skeleton has a three-dimensional carbon-carbon atom structure in which SP ³ and SP ² bonds are mixed. Shows a thin film with. In addition, examples of other atoms contained in the carbon thin film include hydrogen (H), fluorine (F), and oxygen (O).

Here, the carbon thin film may be formed inside or outside the member for connecting the fuel container,
Furthermore, the film may be formed on both sides. The carbon thin film may be provided inside the fuel container connecting member.
For example, as shown in FIG. 1, a fuel container connecting member having the carbon thin film 5a on its outer surface can be used. Further, as shown in FIG. 2, after the carbon thin film 5b is formed on the outer surface of the fuel container connecting member, the carbon thin film is embedded in a resin (for example, polyolefin such as polyethylene) forming the member. It is preferable to use the intermediate layer (overmold type). The carbon thin film is excellent in self-lubricating property and scratch resistance, but by protecting the carbon thin film with such a structure, the loss of the carbon thin film can be remarkably reduced when sliding with other parts.

The carbon thin film contains carbon atoms (C) and hydrogen atoms (H), and the atomic ratio is carbon: hydrogen = 3 :.
It is preferably 7 to 8: 2. As a result, the thermal stability and mechanical strength of the carbon thin film tend to be good. If the proportion of carbon is higher than the above range, the brittleness of the carbon thin film tends to become stronger, and if the proportion of carbon decreases, the carbon thin film may not have sufficient hardness.

Further, elements such as fluorine (F) can be added to the carbon thin film together with C and H from the viewpoint of suppressing fuel permeation. However, from the viewpoint of further improving the durability and permeation resistance to the fuel, a carbon thin film composed of only C and H is preferable, and when C: H = 3: 7 to 8: 2, the carbon thin film to the fuel is Physical durability (difficulty of swelling) and fuel permeation resistance are high, and a more desirable film composition is obtained.

Further, in the fuel container connecting member of the present invention, it is preferable that at least a joint portion with the fuel container is made of the same resin as a joint portion of the fuel container. That is, in this fuel container connecting member, since the carbon thin film having fuel permeation resistance functions as a barrier material, the resin species for forming the carbon thin film is not limited, but improves the bonding strength with the fuel container. It is effective that at least the joint portion is made of the same material as the joint portion of the fuel container. Examples of such a resin include polyethylene (P
E), polypropylene (PP), polyamide (PA), polyester (PET), etc. can be mentioned.

It is preferable that at least the joint portion of the fuel container connecting member is made of high density polyethylene (HDPE). In this case, since the fuel container connecting member of the present invention can be easily obtained by providing a carbon thin film on the commonly used connecting member made of HDPE, in addition to the advantage that the joint strength is improved. The fuel permeation resistance of the fuel container connecting member can be improved at low cost without changing the mold or the material.

Next, the method for manufacturing the fuel container connecting member of the present invention will be described in detail. In this manufacturing method,
A carbon thin film is formed on the film formation surface exposed to plasma of a fluorine-containing gas, hydrogen gas or oxygen gas, and a gas in which any of these is mixed to obtain the above-mentioned fuel container connecting member.
By pretreatment with such a plasma gas, dirt (oil or the like) on the film formation surface is released as a gas, the carbon thin film is stabilized, and the durable life is significantly improved.
Further, the fluorine-containing gas, hydrogen gas or oxygen gas, and the plasma of a gas obtained by arbitrarily mixing these gases is used because it has a large effect of removing dirt and a small influence on the film forming process. This is because these are excellent. In addition, as the fluorine-containing gas, fluorine gas, nitrogen trifluoride gas, sulfur hexafluoride gas, carbon tetrafluoride, silicon tetrafluoride, silicon hexafluoride, chlorine trifluoride, hydrogen fluoride, etc. It can be exemplified, but is not particularly limited to these gases.

The carbon thin film is preferably formed by the plasma CVD method. In this case, there is an advantage that the film-forming surface can be treated with the plasma gas in the same apparatus. Here, the “plasma CVD method” is a method in which electric discharge is performed in a dilute gas to radicalize gas molecules, and the base material is exposed to the radicals to form a film on the surface of the base material. In addition to the plasma CVD method,
A sputtering method, an ion plating method, and the like can be mentioned. With these methods as well, similar to the plasma CVD, the temperature rise during film formation is small, and it is possible to suppress the thermal deterioration of the fuel container connecting member. However, the membrane performance,
In particular, since the durability depends largely on the treatment of the film-forming surface, it is preferable to adopt the plasma CVD method that can be carried out in the same apparatus as the treatment of the film-forming surface, which is also advantageous from the productivity.

Hexane is preferably used in the plasma CVD method. In this case, a carbon thin film having an excellent fuel permeation resistance, particularly an atomic ratio of carbon: hydrogen =
This is effective because a carbon thin film of 3: 7 to 8: 2 can be obtained. In addition to hexane, hydrocarbon gas such as methane, ethane, propane, butane, acetylene and benzene can be appropriately selected and used. Further, as the carrier gas, hydrogen gas or an inert gas can be appropriately used.

Further, when forming a carbon thin film, it is preferable to execute a modulation step for modulating plasma, typically during film formation by a plasma CVD method. From this, in the continuous plasma CVD method, micro defects are likely to occur during film formation, and the fuel may permeate through these defects. However, by modulating, the defect generation is significantly reduced, and the fuel permeation resistance performance is improved. It is possible to stably provide an excellent film. Specifically, at least once and 10 times
The plasma intensity can be reduced to ½ or less of the average plasma intensity during film formation, and more preferably to 0 for 120 seconds. For example, like the modulated plasma shown in FIG. 3, during the film formation, the normal output voltage can be reduced to 1/2 (a) or the output voltage can be set to 0 (b) for 60 seconds. it can. The film quality can be changed if the voltage modulation time is 10 seconds or more. On the other hand, 120
If the time exceeds the second, not only the production tact becomes longer, but also the quality of the carbon thin film may be significantly deteriorated.

Next, the fuel container of the present invention will be described in detail. Such a fuel container is formed by using the above-mentioned fuel container connecting member, and for example, as shown in FIG. 1 or 2,
An example is a fuel container 1 in which the fuel container connecting member 2 is integrated with the container portion 4 via the joint 3. Also,
The member and the container portion can be joined by welding by a hot plate welding method, a vibration welding method, a laser welding method, or the like. Further, for the container part, the same resin as that for the connecting member can be used, and for example, polyethylene (PE), polypropylene (PP), polyamide (PA), polyester (PET) or the like can be used. In addition, it is desirable that a carbon thin film is not formed at the joint between the member and the container. This is because when the carbon thin film is formed, the bonding strength is reduced as compared with the part where the carbon thin film is not formed. Further, when a plasma CVD method or an ion plating method is adopted as a method for forming a carbon thin film, it is efficient because a non-film-forming surface can be easily formed at a desired position by masking the bonding surface.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, in the following Examples 1 to 10 and Comparative Examples 1 to 3, resin plates capable of forming a fuel container connecting member were manufactured, and in Examples 11 and 12, fuel tanks were manufactured and their fuel permeation resistance was Also, the scratch resistance was evaluated.

(Example 1) High-density polyethylene (HDP)
After cleaning the plate surface made of E) with hydrogen gas plasma, a carbon thin film is formed by plasma CVD using hexane gas (film forming time 10 min, frequency 13.56 MH).
z, power 200 W) to obtain a resin plate of this example. In addition,
The thickness of the carbon thin film is 0.5 from the image observed with an electron microscope.
and the film composition was C: H = 6: 4 by XPS (X-ray photoelectron spectroscopy).

Example 2 The same operation as in Example 1 was repeated except that methane gas was used in plasma CVD,
The resin plate of this example was obtained. The thickness of the carbon thin film was 0.5 μm from the image observed with an electron microscope, and the film composition was X.
From PS, it was C: H = 3: 7.

Example 3 The same operation as in Example 1 was repeated except that the cleaning was performed with oxygen gas plasma.
The resin plate of this example was obtained. The thickness of the carbon thin film was 0.5 μm from the image observed with an electron microscope, and the film composition was X.
From PS, it was C: H = 6: 4.

Example 4 A resin plate of this example was obtained by repeating the same operation as in Example 1 except that the cleaning was performed with sulfur hexafluoride gas plasma. In addition, the film thickness of the carbon thin film was 0.5 μm from an image observed by an electron microscope, and the film composition was C: H = 6: 4 from XPS.

Example 5 A resin plate of this example was obtained by repeating the same operation as in Example 1 except that the film forming time was 100 minutes. The film thickness of the carbon thin film was 5 μm from the image observed with an electron microscope, and the film composition was XPS to C: H.
= 6: 4.

Example 6 A resin plate of this example was obtained by repeating the same operation as in Example 1 except that the film formation time was 1 minute. The film thickness of the carbon thin film was 0.05 μm from the image observed with an electron microscope, and the film composition was C: H = 6: 4 from XPS.

Example 7 The resin plate of this example was obtained by repeating the same operation as in Example 1 except that acetylene gas was used in plasma CVD. In addition, the film thickness of the carbon thin film was 0.5 μm from an image observed by an electron microscope, and the film composition was C: H = 8: 2 from XPS.

(Example 8) A resin plate of this example was obtained by repeating the same operation as in Example 1 except that a mixed gas of hexafluoropropane and methane was used in plasma CVD. The film thickness of the carbon thin film was 0.5 μm from the image observed with an electron microscope.
m, and the film composition is from XPS to C: H: F = 4: 1 :.
It was 5.

(Embodiment 9) During film formation, electric power is set to 1 for 10 seconds.
The same operation as in Example 1 was repeated except that the film was formed to 00 W to obtain a resin plate of this example. The thickness of the carbon thin film was 0.5 μm from the image observed with an electron microscope,
The film composition was C: H = 6: 4 from XPS.

Example 10 A resin plate of this example was obtained by repeating the same operation as in Example 1 except that the film was formed by applying an electric power of 0 W for 120 seconds. The thickness of the carbon thin film was 0.4 μm from the image observed by an electron microscope,
The film composition was C: H = 6: 4 from XPS.

(Embodiment 11) Except that a carbon thin film was formed on the surface of the filler neck valve, substantially the same operation as in Embodiment 1 was repeated, and then the joint was connected to the fuel tank main body (3 types, 5 layers fuel tank, outside). The surface was made of HDPE) and a hot plate was welded to the joined portion to obtain a fuel tank of this example. At this time, a masking tape was attached to the joint portion so that no film was formed. The film thickness of the carbon thin film was 0.5 μm from an image observed by an electron microscope, and the film composition was XPS C: H = 6:
It was 4.

(Example 12) After the carbon thin film was formed on the surface of the filler neck valve, the same operation as in Example 1 was repeated except that HDPE was overmolded on the surface of the film. A hot plate was welded to the joined portion of the main body (3 type 5 layer fuel tank, outer surface made of HDPE) to obtain the fuel tank of this example. At this time, a masking tape was attached to the joint portion so that no film was formed. The thickness of the carbon thin film is 0.5 μm from the image observed with an electron microscope.
And the film composition was C: H = 6: 4 from XPS.

Comparative Example 1 An HDPE plate was used as the resin plate of this example.

Comparative Example 2 A resin plate of this example was obtained by repeating the same operation as in Example 1 except that the film forming time was 200 minutes. The thickness of the carbon thin film is 10 μm from an image observed by an electron microscope, and the film composition is XPS to C:
H = 6: 4.

Comparative Example 3 A resin plate of this example was obtained by repeating the same operation as in Example 1 except that the film forming time was 20 seconds. The film thickness of the carbon thin film was 0.01 μm from the image observed with an electron microscope, and the film composition was C: H = 6: 4 from XPS.

<Performance Evaluation Method> 1) Fuel Permeation Resistance Resin plates prepared in Examples 1 to 10 and Comparative Examples 1 to 3,
For the fuel tanks produced in Examples 11 and 12,
Test fuel (a mixture of 90 parts by volume of regular gasoline and 10 parts by volume of ethanol) was placed in an aluminum container conforming to JIS Z0208, and the test fuel was stored at 40 ° C. for about 5 minutes.
A comparison was made using the fuel permeation coefficient after 00 hours had elapsed. As shown in Table 1, the fuel permeation coefficient is shown as a relative value when the value of Comparative Example 1 is 100.

2) Scratch resistance Resin plates prepared in Examples 1 to 10 and Comparative Examples 1 to 3,
For the fuel tanks produced in Examples 11 and 12,
The surface of the spatula made of stainless steel is about 0.98N
It was rubbed with a load of (0.1 kgf), and scratch resistance was evaluated with a magnifying glass.

[0043]

[Table 1]

As shown in Table 1, since the resin plate and the fuel tank obtained in the examples are provided with the carbon thin film having a predetermined film pressure, they have good fuel permeation resistance and scratch resistance. On the other hand, it can be seen that the resin plates obtained in Comparative Examples have poor fuel permeation resistance or scratch resistance.

Although the present invention has been described in detail with reference to the preferred examples and comparative examples, the present invention is not limited to these examples, and various modifications can be made within the scope of the gist of the present invention. . For example, the carbon thin film is provided in a portion other than the joint portion of the fuel container connecting member, but at this time, if it is in the resin layer other than the joint portion, it may be provided in a desired portion or may be provided in a scattered manner. Further, the fuel container connecting member can be manufactured by laminating the carbon thin films alone or alternately laminating with other resin layers. Further, the fuel to which the fuel container connecting member and the fuel container of the present invention are applicable include gasoline, light oil, methanol mixed gasoline, ethanol mixed gasoline, and kerosene.

[0046]

As described above, according to the present invention, since the carbon thin film is provided with a predetermined film thickness, the fuel permeation resistance is improved, the compatibility with the bonding strength is achieved, and the cost is low. A fuel container connecting member, a method for manufacturing the member, and a fuel container can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a fuel container using a fuel container connecting member and an enlarged view of a film forming section.

FIG. 2 is a cross-sectional view showing another example of a fuel container using a fuel container connecting member and an enlarged view of a film forming section.

FIG. 3 is an image diagram of modulated plasma.

[Explanation of symbols]

1 fuel container 2 Fuel container connecting members 3 joints 4 container 5a, 5b carbon thin film

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsumi Moroboshi             Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan             Inside the automobile corporation (72) Inventor Hiroshi Kumagai             Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan             Inside the automobile corporation (72) Inventor Kiyokazu Wakita             Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan             Inside the automobile corporation F term (reference) 3D038 CA04 CA15 CB01 CC20                 3E070 AA02 AB03 DA07 GB01                 4K030 AA10 AA17 BA27 CA07 CA16                       DA02 FA10 JA20

Claims (11)

[Claims] 1. A resin-made tubular fuel container connecting member capable of being joined to a resin-made fuel container through a joint portion, wherein a carbon thin film having a thickness of 0.05 to 5 μm is provided in addition to the joint portion. A member for connecting a fuel container, comprising: 2. The carbon thin film comprises carbon atoms and hydrogen atoms, and the atomic ratio is carbon: hydrogen = 3: 7 to 8: 2.
The fuel container connecting member according to claim 1, wherein 3. The fuel container connecting member according to claim 1, wherein the carbon thin film comprises carbon atoms and hydrogen atoms. 4. The fuel container connecting member according to claim 1, wherein the carbon thin film serves as an intermediate layer. 5. The at least the joint portion is made of the same resin as the joint portion of the fuel container.
The fuel container connecting member according to any one of items 1 to 4. 6. The fuel container connecting member according to claim 5, wherein at least the joint portion is made of high density polyethylene. 7. A method for manufacturing the fuel container connecting member according to any one of claims 1 to 6, wherein the film formation surface is selected from the group consisting of fluorine-containing gas, hydrogen gas and oxygen gas. A method of manufacturing a member for connecting a fuel container, which comprises forming a carbon thin film after exposing to plasma of at least one selected gas. 8. The method for manufacturing a fuel container connecting member according to claim 7, wherein the carbon thin film is formed by a plasma CVD method. 9. The method for manufacturing a fuel container connecting member according to claim 8, wherein the plasma CVD method is performed using hexane gas. 10. When the carbon thin film is formed, a modulation step is performed at least once for 10 to 120 seconds to reduce the plasma intensity to ½ or less of the average plasma intensity during film formation. The method for manufacturing a member for connecting a fuel container according to any one of claims 7 to 9. 11. A fuel container comprising the fuel container connecting member according to any one of claims 1 to 6.