JPH11179806A - Manufacturing method of hollow resin container - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To sufficiently remove gas between a sheet material and a resin layer, and to surely prevent a capacity reduction of a container. SOLUTION: When welding the peripheral edges of a resin layer 36 of a combined intermediate molded product 38, a pipe 54 communicating the inside and the outside of the resin layer 36 is provided at the welded portion of the resin layer 36. A plurality of openings 55 are formed at predetermined intervals along the circumferential direction in a side wall portion of a portion of the pipe 54 that is located inside the resin layer, and a decompression pump (not shown) is connected to the pipe 54. The gas between the gas barrier sheet 10 and the resin layer 36 is discharged, and the slack portion of the gas barrier sheet 10 projecting into the hollow resin container (fuel tank) 28 is removed from the resin layer 3.
6 (gas discharge step).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a hollow resin container, and more particularly to a method for manufacturing a hollow resin container such as a fuel tank mounted on an automobile.

[0002]

2. Description of the Related Art An example of a method for manufacturing a hollow resin container such as a fuel tank mounted on an automobile is disclosed in Japanese Patent Application No. Hei.
178379 (unpublished).

As shown in FIG. 9A, in this method for manufacturing a hollow resin container, a resin layer 106 is formed outside a gas barrier sheet 104 for preventing gasoline from permeating in molds 100 and 102. A concave intermediate molded product 108 is formed.

Next, as shown in FIG. 9B, two intermediate molded products 108 set on press dies 112 and 114 are formed.
Of the gas barrier sheet 104 are welded together.
Into a bag.

Next, as shown in FIG. 9 (C), the peripheral portions 106A of the resin layer 106 are welded to each other to manufacture a hollow resin container 110. At this time, the internal pressure of the bag-like gas barrier sheet 104 is reduced below the external pressure, and the gas barrier sheet 1
04 into the gas barrier sheet 104
Is not sandwiched between the resin layers 106.

[0006]

However, in such a method for manufacturing a hollow resin container, the gas barrier sheet 10 is formed at the welding portion between the peripheral portions 106A of the resin layer 106.
Gas accumulates between the resin layer 4 and the resin layer 106, and the capacity of the container decreases.

As a method for suppressing the decrease in the capacity of the container, as shown in FIG. 10, a gas barrier is provided by a pipe 120 provided at a welding portion of the resin layer 106 and communicating between the inside and outside of the resin layer 106 in a gas discharging step. Sheet 104
A method for discharging gas between the resin and the resin layer 106 has already been filed (Japanese Patent Application No. 9-37974: not disclosed).

However, in this method, when the gas is discharged, the pipe 1 having an opening for sucking the gas is used.
The front end 120A of the 20 faces the slack central portion 104A of the gas barrier sheet 104. For this reason, as shown by a two-dot chain line in FIG.
However, the gas barrier sheet 104 may block the gas, and the gas may not be sufficiently released.

The present invention has been made in consideration of the above-described circumstances, and has as its object to provide a method of manufacturing a hollow resin container which can sufficiently release gas between a sheet material and a resin layer and can surely prevent a decrease in capacity of the container. It is.

[0010]

According to the first aspect of the present invention, there is provided a method for manufacturing a hollow resin container, comprising the steps of: forming a resin layer outside a sheet material to form a concave intermediate molded product; A sheet material welding step of superimposing the peripheral parts of at least two intermediate molded products and welding the peripheral parts of the sheet material to form a bag, and in a state where the internal pressure of the bag-shaped sheet material is lower than the external pressure, A resin welding step of welding the peripheral portions of the resin layer to each other, and a communication passage having an opening in a side wall portion of a portion inside the resin layer, which communicates the inside and outside of the resin layer with the welded portion of the resin layer. And a gas discharging step of discharging gas between the sheet material and the resin layer by the communication path.

Therefore, in the gas discharging step, when the gas between the sheet material and the resin layer is discharged by the communication path provided in the welded portion of the resin layer and communicating between the inside and the outside of the resin layer, the side wall of the communication path is discharged. Since the portion has an opening for sucking gas, the opening does not face the loosened central portion of the sheet material. For this reason,
The opening is hardly closed by the sheet material, the gas between the sheet material and the resin layer can be sufficiently released, and the capacity reduction of the container can be reliably prevented.

According to a second aspect of the present invention, in the method for manufacturing a hollow resin container according to the first aspect, the communication path is a pipe, and an opening is also formed on an end surface of a portion inside the resin layer. It is characterized by having.

Therefore, in addition to the contents described in the first aspect, the opening formed in the end face of the pipe and the side wall of the pipe are formed until the opening formed in the end face of the pipe is closed by the sheet material. The gas between the sheet material and the resin layer is exhausted by both of the openings provided, so that the gas can be exhausted in a short time.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The hollow resin container of the present invention (for example,
One embodiment of a method of manufacturing a fuel tank for an automobile will be described in detail with reference to FIGS.

First, as shown in FIG. 5A, the periphery of a gas barrier sheet 10 as a sheet material is sandwiched between a hot plate 12 including a heater and a holding plate 14. The gas barrier sheet 10 has a well-known laminated structure in which a gas barrier layer having gas barrier properties is sandwiched between resin layers of the same type as the resin of the base material of the hollow resin container. Layer, ethylene vinyl alcohol (EVO
H) layer and the like, and the resin layer is made of the same kind of resin layer as the resin (for example, polyethylene resin) of the base material of the hollow resin container. The gas barrier sheet 10 has improved gas permeation resistance due to the gas barrier layer, and improved adhesion to the base material of the hollow resin container due to the resin layer.

Next, as shown in FIG. 5 (B), the gas barrier sheet 10 is placed on an accessory such as the cutoff valve 16 from the outside (in the state of being a container, from the outside of the container). The accessory parts such as the gas barrier sheet 10 and the cutoff valve 16 are set on a lower mold 18 for forming a base material. In this case, the gas barrier sheet 10 can be easily brought into close contact with the surface of the lower mold 18 by depressurizing the lower mold 18 of the gas barrier sheet 10. In this state, the upper mold 20 is set on the lower mold 18 and the gas barrier sheet 10
A cavity 22 is formed between the upper mold 20 and the inner surface of the upper mold 20.

As shown in FIG. 6, the cut-off valve 1
6 is a hollow resin container 2 composed of a lower part 24 and an upper part 26
The fuel tank 8 closes when the fuel level in the fuel tank rises to the valve position due to turning of the vehicle or the like. The gas released from the cutoff valve 16 is released to the outside of the tank through a pipe (not shown) inserted through the fuel pump mounting opening 32 and the like.

Next, as shown in FIG. 5C, a molten resin is poured into the cavity 22 (outside of the gas barrier sheet 10) through the hole 40 of the upper mold 20 and solidified by cooling to form a resin layer 36. . After the resin layer 36 is solidified, the holding plate 14 is removed, and an intermediate molded product 38 having a concave shape and an opening peripheral portion is formed.

A hole 42 is formed in the hot plate 12, and the molten resin is guided to the gas barrier sheet 10 through the hole 40 so that the hot plate 1 in the gas barrier sheet 10 is removed.
The portion in contact with 2 is held on the hot plate 12 so that the portion of the gas barrier sheet 10 in contact with the hot plate 12 does not wrinkle. The portion of the gas barrier sheet 10 that is in contact with the hot plate 12 is a portion corresponding to a welded portion between the gas barrier sheets 10 in the next step.
The reliability of welding between the 0s is improved.

As shown in FIG. 6, a sub-tank 4 which is an accessory formed on the fuel tank lower part 24 is provided.
4 and the separator 46 are integrally formed at the time of forming the resin layer.

Next, as shown in FIG. 5D, the intermediate molded product 38 is separated by at least one other
The two intermediate molded products 38 and the peripheral edges of the openings are combined with the peripheral edge of the gas barrier sheet 10 (sheet material welding step). In this state, the holding plate 14 has already been removed from the intermediate molded product 38.

Next, as shown in FIG. 5 (E), the combined intermediate molded products 38 are combined in a state where the resin layer portions in contact with the respective hot plates 12 are softened. The hot plates 12 of each of the articles 38 are withdrawn along with the portion of the gas barrier sheet 10 therebetween.

Next, as shown in FIG. 1, the pair of dies 50 (upper dies) and dies 52 (lower dies) of the welding press are brought close to each other to press the combined intermediate molded products 38 together to press the combined intermediate products. The peripheral edges of the resin layer 36 of the molded article 38 are welded together (resin welding step).

At this time, a pipe 54 as a communication passage communicating between the inside and the outside of the resin layer 36 is inserted into the welded portion of the resin layer 36.

As shown in FIG. 3, a circular hole opening 5 is formed on a side wall 54A of the pipe 54 at a position inside the resin layer.
5 are provided at predetermined intervals along the circumferential direction. In addition, an end face inside the resin layer of the pipe 54 is closed by a bottom wall portion 54B.

Further, the welding between the peripheral portions of the resin layer 36 is as follows.
Since it must be performed in a state where the hot plate contact portion of the resin layer 36 is softened in a gel state, it must be performed immediately after the hot plate is pulled out. The hot plate 12 can be divided into a plurality in the circumferential direction so that the hot plate 12 can be pulled out at least in two directions (for example, in four directions) with respect to the intermediate molded product 38.

In the resin welding step, when the process of FIG. 5 (E) shifts to the step of FIG.
The inside of the bag-shaped gas barrier sheet 10 is depressurized so that the welded portion of the gas barrier sheet 10 does not sag and enter between the opposing resin layers, and the slack of the gas barrier sheet 10 is reduced as shown in FIG. (Fuel tank) 28 to protrude.

In this case, as a pressure reducing pipe, a pipe attached to a hollow resin container (fuel tank) 28 can be used.
(See FIG. 6) and the inlet pipe opening 30 (see FIG. 6). A vacuum pump can be connected to this to reduce the pressure inside the container.

Next, as shown in FIG. 2, a vacuum pump (not shown) is connected to the pipe 54 to discharge the gas between the gas barrier sheet 10 and the resin layer 36, and a hollow resin container (fuel tank) is formed. The slack of the gas barrier sheet 10 protruding into the inside 28 is brought into contact with the resin layer 36 (gas discharging step).

At this time, the gas barrier sheet 10 is welded to the resin layer 36 depending on the temperature of the resin layer 36.

Finally, the pipe 54 for gas discharge is closed, and the hollow resin container (fuel tank) 2 of the pipe 54 is closed.
The portion protruding from 8 is cut off with a cutter or the like, and the hollow resin container (fuel tank) 28 is removed from the pair of dies 50 (upper die) and 52 (lower die) of the welding press (the state shown in FIG. 4). ).

Next, the operation of the method for manufacturing a hollow resin container of the present embodiment will be described. In the method for manufacturing a hollow resin container according to the present embodiment, in the gas discharging step (see FIG. 1), the gas barrier sheet 10 and the resin layer are provided by a pipe 54 provided at a welded portion of the resin layer 36 and communicating between the inside and the outside of the resin layer 36. 36
The gas between is discharged. At this time, since the side wall 54A of the pipe 54 has the opening 55 for sucking the gas, the opening 55 does not face the slack central portion 10A of the gas barrier sheet 10. Therefore, the opening 55 is not easily closed by the gas barrier sheet 10, the gas between the gas barrier sheet 10 and the resin layer 36 can be sufficiently removed, and the gas reservoir is eliminated, and the hollow resin container is removed. It is possible to reliably prevent the capacity of the (fuel tank 28) from decreasing.

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to such an embodiment, and various other embodiments are included in the scope of the present invention. It is clear to a person skilled in the art that is possible. For example, in the present embodiment, as shown in FIG.
Although the pipe 54 is used as the communication passage, the communication passage is not limited to the pipe 54, and another member such as a hollow square member may be used. In the present embodiment, as shown in FIG.
Although the end face of the pipe 54 on the inner side of the resin layer is closed by the bottom wall portion 54B, an opening 57 is formed on the end face of the pipe 54 on the inner side of the resin layer, as shown in FIG.
May be formed. In this case, the opening 57 formed on the end face of the pipe 54 and the side wall 54A of the pipe 54 are formed until the opening 57 formed on the end face of the pipe 54 is closed by the gas barrier sheet. The gas between the gas barrier sheet and the resin layer is discharged by both the opening 55 and the gas, so that the gas can be discharged in a short time.

The number of the openings 55 formed in the side wall 54A of the pipe 54 may be one, and the shape of the openings 55 is not limited to a round hole, as shown in FIG. The opening 55 may have an elongated hole (slit) shape. Also,
As shown in FIG. 8B, a part of the end of the pipe 54 may be formed as a cutout opening 55 along the axial direction. Also,
As shown in FIG. 8C, an opening 57 is formed in the end face inside the resin layer of the pipe 54, and a triangular opening 55 is formed in the side wall 54A of the pipe 54 from the opening 57 side. It may be formed. As shown in FIG. 8D, an opening 57 is formed in the end face inside the resin layer of the pipe 54, and a rectangular opening is formed in the side wall 54A of the pipe 54 from the opening 57 side. 55 may be included.

Further, in this embodiment, the fuel tank 28 of an automobile is taken as an example of the hollow resin container. However, the hollow resin container is not limited to the fuel tank 28 of an automobile, but may be another hollow resin container. Further, the sheet material is not limited to the gas barrier sheet 10 and may be another sheet material. In the present embodiment, the case of injection molding is shown, but the present invention is also applicable to injection press molding, hot flow stamping molding, and sheet flow stamping molding.

[0036]

According to the first aspect of the present invention, there is provided a method for manufacturing a hollow resin container, comprising the steps of: forming a resin layer outside a sheet material to form a concave intermediate molded product; A sheet material welding step in which the peripheral parts of the intermediate molded product are overlapped and the peripheral parts of the sheet material are welded to each other to form a bag, and in a state where the internal pressure of the bag-shaped sheet material is lower than the external pressure, the peripheral parts of the resin layer And a communication path having an opening in a side wall of a portion inside the resin layer, and a sheet material is formed by the communication path. And a gas discharging step of discharging gas between the resin layer and the resin layer, so that the gas between the sheet material and the resin layer can be sufficiently removed and the capacity of the container can be reliably prevented from being reduced. Has an effect.

According to a second aspect of the present invention, in the method for manufacturing a hollow resin container according to the first aspect, the communication path is a pipe, and an opening is also formed at an end surface of a portion inside the resin layer. Therefore, in addition to the effect described in claim 1, there is an excellent effect that gas between the sheet material and the resin layer can be released in a short time.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a gas discharging step of a method for manufacturing a hollow resin container according to one embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a state after a gas discharging step of the method for manufacturing a hollow resin container according to one embodiment of the present invention.

FIG. 3 is a perspective view showing a communication path in the method for manufacturing a hollow resin container according to one embodiment of the present invention.

FIG. 4 is a schematic sectional view showing a container manufactured by the method for manufacturing a hollow resin container according to one embodiment of the present invention.

FIGS. 5A to 5E are schematic sectional views showing a part of a method for manufacturing a hollow resin container according to an embodiment of the present invention in the order of steps.

FIG. 6 is an exploded perspective view showing a container manufactured by the method for manufacturing a hollow resin container according to one embodiment of the present invention.

FIG. 7 is a perspective view showing a modification of the communication path in the method for manufacturing a hollow resin container according to one embodiment of the present invention.

FIGS. 8A to 8D are perspective views showing another modification of the communication path in the method for manufacturing a hollow resin container according to one embodiment of the present invention.

FIGS. 9A to 9C are schematic cross-sectional views illustrating a method of manufacturing a hollow resin container according to a conventional embodiment in the order of steps.

FIG. 10 is a schematic sectional view showing a gas discharging step of a method for manufacturing a hollow resin container according to a conventional embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Gas barrier sheet (sheet material) 28 Hollow resin container 36 Resin layer 38 Intermediate molded product 54 Pipe (communication passage) 54A Side wall of pipe 55 Opening formed in side wall of pipe 57 Opening formed in end face of pipe

Claims (2)

[Claims] An intermediate molded product forming step of forming a concave intermediate molded product by forming a resin layer on the outer side of the sheet material; and superimposing peripheral portions of at least two intermediate molded products, and forming a peripheral portion of the sheet material. A sheet material welding step of welding the two to form a bag, a resin welding step of welding the peripheral portions of the resin layer to each other with the internal pressure of the bag-shaped sheet material being lower than an external pressure, and welding the resin layer The inside and outside of the resin layer communicate with the portion, and a communication passage having an opening in a side wall portion of a portion inside the resin layer is provided, and the gas between the sheet material and the resin layer is provided by the communication passage. A method for producing a hollow resin container, comprising the steps of: 2. The method for manufacturing a hollow resin container according to claim 1, wherein the communication path is a pipe, and an opening is formed at an end surface of a portion inside the resin layer.