JP2009255891A - Fuel hose for resin fuel tank and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel hose for a resin fuel tank weldable directly to the resin fuel tank without a joint interposed therebetween and a method of manufacturing the fuel hose. <P>SOLUTION: This fuel hose comprises a three layer structure in which a welding layer 2 formed of HDPE is formed on the inner and outer peripheral surfaces of a barrier layer 1 made of an alloy material mainly comprising polyamide 6, modified HDPE, and HDPE. One end opening of the fuel hose is formed in an enlarged-diameter and thick section. The enlarged-diameter section (thick section) is formed by reducing a die moving speed when a hose base is extruded to the enlarged-diameter section of the die surface of a die during the extrusion molding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

A joint for connecting a fuel hose is welded to the outer periphery of the mouth of a resin fuel tank for automobiles (see, for example, Patent Document 1).
JP 2006-143171 A

  Since the fuel hose and the joint are separate parts, the number of parts required for the connection between the resin fuel tank and the fuel hose is large, and the connection structure is complicated. For this reason, the parts management cost and the manufacturing cost are high. Further, as the number of parts increases, the number of connecting portions also increases, and accordingly, there is a high risk that fuel will permeate from the connecting portions.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a fuel hose for a resin fuel tank that can be directly welded to a resin fuel tank without using a joint, and a method for manufacturing the same.

In order to achieve the above object, the present invention provides a substantially cylindrical barrier layer comprising the following (A), and a substantially cylinder comprising the following (B) formed on the inner and outer peripheral surfaces of the barrier layer. A three-layer structure composed of an annular weld layer, and a substantially cylindrical one end opening of the three-layer structure is formed in the enlarged diameter portion and in the thick portion, and the opening of the resin fuel tank The first aspect is a resin fuel tank fuel hose formed in a welded part of the outer peripheral surface of the part to the polyethylene layer.
(A) An alloy material mainly composed of polyamide 6, modified high-density polyethylene, and high-density polyethylene, and the blending ratio of the polyamide 6 is set in the range of 30 to 45% by weight.
(B) High density polyethylene.

  Further, the present invention is configured to circulate and rotate the endless annular upper and lower connected dies in which a plurality of upper and lower dies that form a substantially cylindrical molding space are connected to each other. At one end, the pair of upper and lower molds are sequentially abutted to form the molding space, and a substantially cylindrical hose base made of a fuel hose forming material is extruded from the extruder into the molding space. By closely contacting the mold surface of the molding space, the hose base is continuously molded into a hose shape, and at the other end, the pair of the upper mold and the lower mold that are butted together are sequentially separated. , A method for producing a fuel hose for a resin fuel tank in which a formed hose is continuously demolded, which is formed by a predetermined upper mold and a lower mold among the plurality of upper molds and lower molds An enlarged diameter portion is formed on the mold surface of the molding space to be The hose base body is a substantially cylindrical barrier layer base material made of (A) above, and the substantially cylindrical weld made of the above (B) formed on the inner and outer peripheral surfaces of the barrier layer base material. A three-layer structure comprising a layer base material, and when the hose base is pushed out of the extruder onto the diameter-expanded portion of the mold surface, the rotational rotational speed of the connected upper mold and the connected lower mold The hose base portion extruded to the enlarged diameter portion is formed at the enlarged diameter portion and the thick portion, and after demolding, the resin that cuts the enlarged diameter portion along the circumferential direction. The manufacturing method of the fuel hose for the fuel tank is the second gist.

  That is, a fuel hose for a resin fuel tank according to the present invention includes a substantially cylindrical barrier layer made of (A) and a substantially cylinder made of (B) formed on the inner and outer peripheral surfaces of the barrier layer. By having a three-layer structure composed of a welded layer, the barrier layer composed of (A) exhibits excellent barrier properties against fuel, and the welded layer composed of (B) above is made of resin. Excellent welding power to the polyethylene layer on the surface of the fuel tank. In addition, the adhesive force between the barrier layer and the weld layer is large, so that the interface between the two layers is not peeled off, and the fuel does not leak from the interface. Furthermore, since the welded portion with the resin fuel tank is formed at the enlarged diameter portion and at the thick portion, the barrier layer is also thickened, so that the barrier property against fuel is also improved. In addition, the welding area between the weld layer and the resin fuel tank is increased, so that the welding force with the resin fuel tank is also improved.

  In the fuel hose for a resin fuel tank of the present invention, the welded portion with the resin fuel tank is formed on the substantially cylindrical barrier layer made of (A) above, and on the inner and outer peripheral surfaces of the barrier layer. Since it has a three-layer structure consisting of a substantially cylindrical weld layer made of (B) above, and is formed in the enlarged diameter portion and in the thick portion, the opening of the resin fuel tank It can be directly welded to the polyethylene layer on the outer peripheral surface, and exhibits excellent welding power and fuel barrier properties. Further, since the joint can be eliminated, the connection between the joint and the hose is eliminated. As a result, the number of parts such as an O-ring can be reduced, and the sealing performance, the pull-out strength, and the like can be improved. .

  Further, in the method for producing a fuel hose for a resin fuel tank according to the present invention, a diameter-expanded portion is formed on a mold surface of a molding space formed by a predetermined upper mold and a lower mold, and the hose from the extruder When the base body is pushed out to the enlarged diameter portion, the moving speed of the upper and lower molds is decreased to form the hose base portion pushed out to the enlarged diameter portion in the enlarged diameter portion and in the thick portion. Therefore, the fuel hose for a resin fuel tank of the present invention can be easily manufactured.

  In the present invention, the “upper mold” and the “lower mold” do not limit the arrangement direction in the vertical direction, but mean a pair of opposed molds. For example, the arrangement direction Means that the left and right are “left mold” and “right mold”.

  In particular, when the above-mentioned enlarged diameter portion is cut with high-pressure jet water, heat generation during cutting can be prevented, so that alteration such as oxidation of the cut surface can be prevented. And in the welding part which welded the fuel hose for resin fuel tanks obtained by this to the resin fuel tank, the welding force and the barrier property with respect to fuel do not fall.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an embodiment of a fuel hose for a resin fuel tank according to the present invention. The resin fuel tank fuel hose (hereinafter simply referred to as “fuel hose”) of this embodiment includes a substantially cylindrical barrier layer 1 and a weld layer 2 formed on the inner and outer peripheral surfaces thereof. It has a three-layer structure. As will be described in detail later, the material for forming the barrier layer 1 is composed mainly of polyamide 6, modified high-density polyethylene (modified HDPE), and high-density polyethylene (HDPE), and the blending ratio of the polyamide 6 is 30 to 45. It is an alloy material set within the range of weight%. The material for forming the weld layer 2 is high density polyethylene (HDPE). Further, one end opening (lower end opening in FIG. 1) of the fuel hose is formed in the enlarged diameter portion and in the thick portion. In the thick portion (expanded portion), both the barrier layer 1 and the weld layer 2 are thick. As shown in FIG. 2, one end opening formed in the enlarged diameter portion and the thick portion has a mouth portion of a resin fuel tank (hereinafter simply referred to as “fuel tank”) 10 described in detail later. 11 is welded to a high density polyethylene (HDPE) layer 12 on the surface of the outer peripheral portion.

  The fuel hose can be manufactured using a molding machine such as a corrugator, a three-dimensional blow molding machine, etc. In this embodiment, as shown in FIG. 3, the following extruder is used as the molding machine. A molding machine having 20 and a mold is used.

  The extruder 20 can continuously extrude the substantially cylindrical hose base body (which will later be formed on the fuel hose) B having the three-layer structure from the extrusion head 21 at the tip. Yes. An air supply pipe 22 that feeds air into the hollow portion of the extruded substantially cylindrical hose base B is provided coaxially with the extrusion head 21. In FIG. 3, the three-layer structure of the hose base B is omitted.

  The mold includes an endless annular coupling upper mold 31 and a coupled lower mold 32 in which a plurality of upper and lower molds forming a substantially cylindrical molding space are coupled to each other. Then, as the connected upper mold 31 and the connected lower mold 32 are circulated and rotated, a pair of upper mold and lower mold are sequentially abutted in the vicinity of the extrusion head 21 of the extruder 20, and the molding is performed. A space is formed. In this embodiment, the molding space has a bellows portion, a straight portion, and an enlarged diameter portion 33 formed at predetermined positions. When the upper mold and the lower mold are brought into contact with each other, in this state, the upper mold and the lower mold are moved in a straight line so as to move away from the extrusion head 21 of the extruder 20 for a while. It comes to separate. Furthermore, a large number of thin slits communicating with the back surfaces of the upper and lower molds are formed on the mold surface of the molding space, and the hose base B pushed out to the mold surface is evacuated through the slits. It is attracted to and closely attached to the mold surface.

And the said fuel hose can be manufactured as follows using the said molding machine. That is, first, the hose base B having the three-layer structure is continuously extruded from the extrusion head 21 of the extruder 20 while the connection upper mold 31 and the connection lower mold 32 are circulated and rotated. The extrusion amount of the hose base B is constant per unit time. In this state, air is sent from the air supply pipe 22 of the extruder 20 to the hollow portion of the hose base B, and the hose base B is brought into close contact with the mold surface by evacuating the mold. Then, when the hose base B is pushed out to the above-mentioned enlarged diameter portion 33 of the mold surface of the molding space of the mold, the rotational speed of rotation between the upper connection mold 31 and the lower connection mold 32 (upper mold and lower mold). ). Thereby, more hose bases B are supplied to the said enlarged diameter part 33 than other parts, and the hose base B part in the enlarged diameter part 33 is formed in a thick part. Thereafter, when the upper mold and the lower mold are separated from each other, the formed hose is removed. The removed hose is molded into a shape corresponding to the mold surface of the molding space, and the bellows part, the straight part, and the enlarged diameter part (thick part) are formed at predetermined positions. Yes. In FIG. 3, the expanded diameter portion of the formed hose is a portion where the one end openings (expanded diameter portions) of the two fuel hoses are abutted, and the straight portion is the other of the two fuel hoses. It is the part where the end openings meet. Then, cut along an axial center of the axial center (one-dot chain line L ₁₎ of the enlarged diameter portion and the straight portion (one-dot chain line L ₂₎ in the circumferential direction. In this way, the fuel hose can be manufactured continuously.

In the production of the fuel hose, the hose formed is first cut every several units (in a state where several fuel hoses are connected) at the straight portion (dashed line L ₂ ). Then, the filling is put into the hollow part to maintain the shape of the hose properly. Then, after cutting with the enlarged diameter portion (one-dot chain line L _1), to remove the padding. Cutting in this manner is preferable from the viewpoint of improving the cutting accuracy of the enlarged diameter portion.

  Moreover, it is preferable that the formed hose is cut with high-pressure jet water with increased water pressure. The reason is that heat generation at the time of cutting can be prevented, and alteration such as oxidation of the cut surface can be prevented, whereby the welding force of the welding portion between the fuel hose and the fuel tank 10 and This is because the barrier property against fuel can be prevented from deteriorating. As such a cutting machine, for example, Aqua Jet Cutter Rb (manufactured by Sugino Machine Co., Ltd.) or the like is opened, and the water pressure of the high-pressure jet water at the time of cutting is set within a range of 200 MPa to 400 MPa.

  The fuel hose manufactured in this way will be described in more detail. The thickness of the peripheral wall of the fuel hose is set within a range of 3 to 20 mm at the thick portion (expanded portion), and the bellows portion and the straight portion. Then, the thickness is set to about 10 to 30%. Among them, the thickness of the barrier layer 1 is set in the range of 300 to 2000 μm in the thick portion (expanded portion), and is set to about 10 to 30% in the bellows portion and the straight portion. Further, the thickness of the weld layer 2 (thickness for one layer) is set within a range of 1.3 to 9.0 mm in the thick portion (expanded portion), and 10 in the bellows portion and the straight portion. The thickness is set to about 30%. And the outer diameter of the said fuel hose is set in the range of 10-80 mm in an enlarged diameter part (thick part), and is set to the outer diameter of about 40-95% in a straight part.

  The material for forming the barrier layer 1 in the three-layer structure of the fuel hose is composed mainly of polyamide 6, modified HDPE and HDPE, and the blending ratio of the polyamide 6 is set within a range of 30 to 45% by weight. Alloy material. Among these, polyamide 6 has a domain, a modified HDPE, and a low fuel permeability (barrier property), and also has an excellent welding power to the HDPE layer 12 that is the outermost layer of the fuel tank 10. It is preferable to use an alloy material in which HDPE forms a matrix (an island phase made of polyamide 6 forms a sea-island structure in which the phase is slightly dispersed in a sea phase made of modified HDPE and HDPE). In addition, the said main component means the component which occupies the majority of the whole, and is the meaning including the case where the whole consists only of a main component.

  The blending ratio of polyamide 6 in the alloy material is set in the range of 30 to 45% by weight as described above. This is because, when the blending ratio of polyamide 6 is less than 30% by weight, it is welded to the weld layer 2, but the barrier property against fuel is lowered, and when it exceeds 45% by weight, the barrier property against fuel is improved, This is because the weldability to the weld layer 2 is lowered.

  The modified HDPE is mainly composed of a maleic anhydride group, maleic acid group, acrylic acid group, methacrylic acid group, acrylic acid ester group, methacrylic acid ester group, vinyl acetate group, epoxy group and amino group. Or it is preferable that it is modified | denatured HDPE which has 2 or more types of functional groups. The modified HDPE may be prepared by grafting a modifying compound such as an unsaturated carboxylic acid and an unsaturated carboxylic acid derivative or an amine-containing compound (such as methylene diamine) in the presence of a radical initiator. It can be obtained by denaturing. Furthermore, the modification rate of the modified HDPE is preferably set in the range of 0.1 to 5.0% by weight, more preferably in the range of 0.2 to 3.0% by weight. The reason for this is that when the modification rate is less than 0.1% by weight, the affinity between the polyamide 6 and the modified HDPE tends to be poor and the barrier property to fuel tends to be inferior. This is because the fuel barrier properties tend to be inferior, and the working environment such as kneading and molding tends to deteriorate. Further, the modified HDPE preferably has a melting point (ISO 3146) in the range of 100 to 145 ° C, particularly preferably in the range of 110 to 135 ° C. The HDPE (high density polyethylene) in the modified HDPE usually has a specific gravity (ISO 1183) of 0.93 to 0.97, preferably 0.93 to 0.96, and a melting point ( ISO 3146) is in the range of 120 to 145 ° C.

  The alloy material is obtained by kneading the polyamide 6, modified HDPE and HDPE. In particular, when the kneading is performed with high shear, the alloy material in which the sea-island structure is formed can be obtained. it can. The kneading with the high shear can be realized by using, for example, a twin screw extruder (kneading machine). Further, it is considered that the hydroxyl group of polyamide 6 and the modified group of modified HDPE form a hydrogen bond or a covalent bond by the kneading. As a result, the affinity between polyamide 6 and modified HDPE is increased, and a finely dispersed sea-island structure is exhibited. Therefore, it is considered that the barrier layer 1 has a low fuel permeation amount and is excellent in low fuel permeability (barrier property).

  The material for forming the weld layer 2 in the three-layer structure of the fuel hose is HDPE. For this reason, the barrier layer 1 contains the same HDPE in the alloy material, so that the compatibility between the barrier layer 1 and the weld layer 2 is good and the adhesive strength is also strong. For this reason, each interface is not peeled off, and there is no possibility of fuel leaking from each interface.

  Furthermore, since the alloy material of the barrier layer 1 has polyamide 6, it is easy to absorb moisture, and the adhesive force may be reduced by the moisture absorption. However, the fuel hose is a surface of the barrier layer (alloy material) 1. In addition, since the welded layer (HDPE) 2 having a water barrier property is formed, moisture absorption is prevented in the storage state before welding, and there is no fear of a decrease in welding force due to moisture absorption after welding.

  The fuel tank 10 is usually a multilayer structure incorporating a fuel low-permeability layer made of a fuel low-permeability material such as EVOH in consideration of prevention of fuel transpiration, and the outermost layer has impact resistance, For reasons such as chemical properties, water resistance, and economic efficiency, HDPE or the like is used as a material. In FIG. 2, a fuel tank 10 having a five-layer structure of HDPE layer 12 / adhesive layer (not shown) / EVOH layer / adhesive layer (not shown) / HDPE layer is illustrated from the outside.

  The method of welding the fuel hose to the outer peripheral surface of the mouth portion 11 of the fuel tank 10 is not particularly limited, but from the viewpoint of obtaining high bonding strength, a hot plate welding method, vibration welding method, ultrasonic welding. A method such as a laser welding method or the like is preferable, but a hot gas welding method or a rotation welding method may be used.

  By the welding, the contact surface portion between the one end opening of the fuel hose and the HDPE layer 12 which is the outermost layer of the fuel tank 10 is melted and welded. In this welding, the fuel hose barrier layer (alloy material mainly composed of polyamide 6, modified HDPE and HDPE) 1 and the outermost layer (HDPE layer 12) of the fuel tank 10 both contain polyethylene. Therefore, the conformability at the interface between both layers 1 and 12 is good. For this reason, the adhesive force of both layers 1 and 12 becomes large, and it does not peel off at the interface between both layers 1 and 12. Therefore, not only the barrier layer 1 itself has high barrier properties, but also the barrier properties at the welded portions of both layers 1 and 12 are enhanced. Further, in the above-mentioned welding, since the weld layer (HDPE) 2 of the fuel hose and the outermost layer (HDPE layer 12) of the fuel tank 10 are both made of HDPE, the conformability at the interface between both layers 2 and 12 is good. In addition, the expansion rate is the same, the adhesion between the layers 2 and 12 is increased, and the adhesion stability is also increased.

  Furthermore, since the welded portion with the fuel tank 10 is formed at the enlarged diameter portion and at the thick portion, the barrier layer 1 is also thickened, so that the barrier property against the fuel is also improved. In addition, the welding area between the weld layer 2 and the fuel tank 10 is widened, so that the welding force with the fuel tank 10 is also improved.

  In addition, since the fuel hose has the above-described three-layer structure (sandwich structure), the barrier layer 1 is protected by HDPE (welded layer 2) having relatively high flexibility and impact resistance. It is rich in softness and has impact resistance.

  In the above embodiment, the fuel hose has a three-layer structure of welding layer 2 / barrier layer 1 / welding layer 2. However, the present invention is not limited to this, and welding layer 2 / barrier layer 1 / welding layer is not limited thereto. The structure may be a five-layer structure of 2 / barrier layer 1 / welded layer 2 or a multilayer structure having more than that. In this case, the number of the weld layers 2 increases, so that the reliability of welding increases.

  Moreover, although the said embodiment demonstrated what the bellows part was formed as a fuel hose, it is not limited to this, The fuel hose in which the bellows part is not formed may be sufficient.

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

[Polyamide 6 (barrier layer material)]
Polyamide 6 (UBE Nylon 1013B, manufactured by Ube Industries, Ltd.) was prepared.

[Modified HDPE (barrier layer material)]
HDPE (Nippon Polyethylene Co., Ltd., Novatec HY430) was blended with 0.4% by weight maleic anhydride and 0.015% by weight 2,5-dimethyl-2,5di (t-butylperoxy) hexane. Modified HDPE was produced by melt-kneading using a kneading extruder. This is designated as modified HDPE-1. On the other hand, a commercially available Umex 2000 (manufactured by Sanyo Chemical Co., Ltd.) was prepared as a modified HDPE using 2.5% by weight of maleic anhydride. This is referred to as modified HDPE-2 (highly modified HDPE).

[HDPE (barrier layer material)]
HDPE (Nippon Polyethylene, Novatec HY430) was prepared.

[Example 1]
[Alloy material (barrier layer material)]
The polyamide 6 was blended in a proportion of 35% by weight, modified HDPE-1 in a proportion of 30% by weight and HDPE in a proportion of 35% by weight, and melt-kneaded using a twin-screw kneading extruder to produce pellets made of an alloy material.

[HDPE (material of welded layer)]
HDPE (manufactured by Nippon Polyethylene Co., Ltd., HB122R) was prepared.

[Fuel hose forming machine]
A 5-layer extruder manufactured by Pla Giken was prepared.

[Manufacture of fuel hose]
Using the above materials and molding machine, in the same manner as in the above embodiment, it has a five-layer structure of welding layer / barrier layer / welding layer / barrier layer / welding layer, the central part is formed in the bellows part, and both end parts are A substantially cylindrical fuel hose formed on the straight part, one end of which was formed on the enlarged diameter part (thick part) could be manufactured. In this production, the moving speed of the upper and lower molds was 4 m / min when the hose base was extruded at the bellows portion and the straight portion, and 0.5 m / min when the hose base was expanded. In addition, when the hose base was pushed out, air was sent from the air supply pipe to the hollow portion of the hose base and evacuated with the above-mentioned mold, thereby bringing the hose base into close contact with the mold surface. The pressure of the supplied air was set to 0.05 MPa (gauge pressure) when the hose base was pushed out of the bellows portion and the straight portion, and 0.2 MPa (gauge pressure) when the hose base portion was expanded. And as for the outer diameter of the manufactured fuel hose, the straight part was 30 mm, the bellows part was 35 mm, and the enlarged diameter part was 45 mm. Further, the thickness of the barrier layer (thickness for one layer) was 70 μm for the bellows part, 150 μm for the straight part, and 600 μm for the enlarged diameter part. The thickness of the welded layer (thickness for one layer) was 200 μm for the bellows part, 400 μm for the straight part, and 1600 μm for the enlarged diameter part. In addition, the said outer diameter was measured using calipers, and the thickness of each layer measured the cross section of the bellows part and the straight part, and the opening surface of the enlarged diameter part with the microscope (the Keyence company make, VH-8000).

[Manufacture of test hose]
As the test hose used for the measurement of the following fuel permeation amount, the above-mentioned material and molding machine were used and a straight part only was manufactured to a length of 300 mm.

[Example 2]
In Example 1 above, the blending ratio of polyamide 6 of the alloy material was changed to 40% by weight, the blending ratio of modified HDPE-1 was changed to 35% by weight, and the blending ratio of HDPE was changed to 25% by weight. A fuel hose and a test hose were manufactured.

Example 3
In Example 1 above, the blending ratio of polyamide 6 of the alloy material was changed to 45% by weight, the blending ratio of modified HDPE-1 was changed to 40% by weight, and the blending ratio of HDPE was changed to 15% by weight. A fuel hose and a test hose were manufactured.

Example 4
In Example 1 above, the blending ratio of polyamide 6 of the alloy material was changed to 30% by weight, the blending ratio of modified HDPE-1 was changed to 25% by weight, and the blending ratio of HDPE was changed to 45% by weight. A fuel hose and a test hose were manufactured.

Example 5
In Example 1 above, the blending ratio of the polyamide 6 of the alloy material was changed to 30 wt%, the blending ratio of the modified HDPE-1 was changed to 10 wt%, the blending ratio of the HDPE was changed to 50 wt%, and the modified HDPE-2 was changed to 10 wt%. A fuel hose and a test hose were produced in the same manner as in Example 1 above.

Example 6
In Example 1, the blending ratio of the polyamide 6 of the alloy material was changed to 35% by weight, the blending ratio of the modified HDPE-1 was changed to 33% by weight, the blending ratio of the HDPE was changed to 30% by weight, and the modified HDPE-2 was added to 2% by weight. A fuel hose and a test hose were produced in the same manner as in Example 1 above.

[Comparative Example 1]
In Example 1, the fuel hose and test hose were manufactured in the same manner as in Example 1 except that the blending ratio of the polyamide 6 of the alloy material was changed to 50% by weight and the blending ratio of the modified HDPE-1 was changed to 50% by weight. . However, kneading and extrusion could not be performed due to the material thickening (fuel hose and test hose could not be manufactured). For this reason, the following barrier properties and the like could not be evaluated.

[Comparative Example 2]
In Example 1, the fuel hose and the test hose were manufactured in the same manner as in Example 1 except that the blending ratio of polyamide 6 of the alloy material was changed to 50% by weight and the blending ratio of HDPE was changed to 50% by weight.

[Measurement of fuel permeation: barrier properties]
In the test hoses of Examples 1 to 6 and Comparative Example 2 above, gasoline (E10) in which 10 vol% ethanol was mixed with regular gasoline (manufactured by Nippon Oil Co., Ltd.) was sealed (both ends of the test hose were sealed with a swage lock). The specimen was left at 40 ° C. for 2 weeks. Then, the fuel permeation amount was calculated from the difference between the mass of the test body at the start of the test and the mass of the test body after 4 weeks. As a result, when the fuel permeation amount is 10 mg / line / day or less, the barrier property is excellent, and when it exceeds 10 mg / line / day and 15 mg / line / day or less, the barrier property is slightly inferior, Δ, 15 mg Those exceeding / line / day were evaluated as x because they were very inferior in barrier properties, and are listed in Table 1 below.

(Interlayer adhesion)
The fuel hoses of Examples 1 to 6 and Comparative Example 2 were set in an ultra high pressure water cutter (Aqua Jet Cutter Rb, manufactured by Sugino Machine Co., Ltd.), and the water pressure was set to 250 MPa and cut. And the cross section was observed. As a result, the interface between the barrier layer and the weld layer was not peeled off, and the one that was fractured outside the interface had excellent interlayer adhesion, and the one that the interface between the barrier layer and the weld layer was peeled off Since it was inferior to interlayer adhesiveness, it was evaluated as x, and is shown in Table 1 below.

[Weldability with tank]
An HDPE sheet material (thickness 8 mm) corresponding to the outermost layer of the fuel tank was prepared, and an opening having the same diameter as the inner diameter of the expanded portion of the fuel hose was formed in the sheet material. Then, by applying a hot plate of 240 ° C. to the outer peripheral surface of the opening for 30 seconds, the portion is heated and melted, and immediately after the hot plate is removed, the enlarged portion of the fuel hose is added to the heated and melted portion. Welded. Then, after sufficiently cooling at room temperature (25 ° C.), it is cut into strips with a width of 10 mm, and the tensile tester (Toyo Seiki) And a tensile test was performed under the condition of a tensile speed of 50 mm / sec. As a result, without being peeled at the interface between the fuel hose and the sheet material, those that were broken at other than the interface were excellent as weldability with the tank, and those peeled at the interface between the fuel hose and the sheet material were It was evaluated as x because it was inferior in weldability with the tank, and was also shown in Table 1 below.

  From the above results, the fuel hoses of Examples 1 to 6 are superior to the fuel hose of Comparative Example 2 in terms of interlayer adhesion between the barrier layer and the weld layer, and are also excellent in weldability with the fuel tank. You can see that

It is sectional drawing which shows typically one Embodiment of the fuel hose of this invention. It is sectional drawing which shows typically the state by which the said fuel hose was welded to the fuel tank. It is explanatory drawing which shows the manufacturing method of the said fuel hose typically.

Explanation of symbols

1 Barrier layer 2 Welding layer

Claims (4)

It has a three-layer structure consisting of a substantially cylindrical barrier layer comprising the following (A) and a substantially cylindrical weld layer comprising the following (B) formed on the inner and outer peripheral surfaces of the barrier layer. In addition, the substantially cylindrical one-end opening of the three-layer structure is formed in the thickened portion while being formed in the enlarged diameter portion, and is formed in the welded portion to the polyethylene layer on the outer peripheral surface of the opening of the resin fuel tank. A fuel hose for a resin fuel tank, wherein
(A) An alloy material mainly composed of polyamide 6, modified high-density polyethylene, and high-density polyethylene, and the blending ratio of the polyamide 6 is set in the range of 30 to 45% by weight.
(B) High density polyethylene.   2. The fuel hose for a resin fuel tank according to claim 1, wherein at least a part thereof is formed in a bellows shape. While circulating and rotating the endless annular upper and lower connected molds in which a plurality of upper molds and lower molds forming a substantially cylindrical molding space are respectively connected, A pair of upper and lower molds are sequentially abutted to form the molding space, and a substantially cylindrical hose base made of a fuel hose forming material is extruded from the extruder into the molding space. The hose base is continuously formed into a hose shape, and at the other end, the pair of the upper mold and the lower mold that are butted together are sequentially separated. A method of manufacturing a resin hose for a resin fuel tank that is continuously demolded, which is a mold of a molding space formed by a predetermined upper mold and a lower mold among the plurality of upper molds and lower molds An enlarged diameter portion is formed on the surface, and the hose base is From the substantially cylindrical barrier layer base material consisting of the following (A), and the substantially cylindrical weld layer base material consisting of the following (B) formed on the inner and outer peripheral surfaces of the barrier layer base material When the hose base is pushed out of the extruder on the diameter-expanded portion of the mold surface, the circulation rotational speed between the connected upper mold and the connected lower mold is reduced. The resin is characterized in that the hose base portion extruded to the enlarged diameter portion is formed in the enlarged diameter portion and the thick portion, and after demolding, the enlarged diameter portion is cut along the circumferential direction. Manufacturing method of fuel hose for fuel tank.
(A) An alloy material mainly composed of polyamide 6, modified high-density polyethylene, and high-density polyethylene, and the blending ratio of the polyamide 6 is set in the range of 30 to 45% by weight.
(B) High density polyethylene.   The method for producing a fuel hose for a resin fuel tank according to claim 3, wherein the cutting of the enlarged diameter portion is performed with high-pressure jet water.

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