JP3099579B2 - Mold for resin container and method for molding resin container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a molding die for molding a resin container and a method of molding a resin container, and more particularly to a method of molding a resin container to a uniform thickness, and a joining strength and airtightness of a joining portion. TECHNICAL FIELD The present invention relates to a resin container molding die and a resin container molding method capable of improving performance.

[0002]

2. Description of the Related Art A container made of resin is generally manufactured by a blow molding method. In the blow molding method, a tubular parison (molten resin) extruded from an extruder
Is sandwiched between two molds, and air is blown into the parison from the blow nozzle with the molds closed. As a result, the parison comes into close contact with the inner wall surface of the mold, and a resin container having a predetermined shape is formed.

When a large-sized resin container is manufactured by the blow molding method, the thickness of the upper portion tends to be smaller than that of the lower portion due to the weight of the parison in a flowing state, and the thickness cannot be made uniform. As one of the technologies to make the thickness of the resin container uniform, sandwich the high-temperature resin material between concave and convex molds, mold it into a predetermined shape, cool it, and join the peripheral edge of the molded product (Japanese Patent Laid-Open No. 59-209)
No. 531).

[0004]

However, in the resin container disclosed in the above publication, since the once cooled peripheral portion is joined, it is difficult to perform reliable welding, and there remains a problem in terms of joining strength and airtightness. In addition, at the time of joining the peripheral portion of the molten resin, the temperature of the peripheral portion is lowered due to the contact between the peripheral portion and the mold, so that the peripheral portion cannot be welded in a high temperature state, and the joining strength and airtightness become problems. .

[0005] The present invention may be molded trees fat container to a uniform thickness, and to provide a method of molding a mold and the resin container of the resin container capable of enhancing the bonding strength and airtightness of the joint portion Aim.

[0006]

The present invention for achieving this object is as follows. (1) a first sheet-like molten resin extruded from the extruder is placed, a first back type in which a recess is formed, prior to
The first back mold is rotatably connected to the first back mold, and is configured to be moldable with the first back mold, and a concave portion is formed on which the second sheet-like molten resin extruded from the extruder is placed.
A second back type that, the first of the first sheet-like molten resin placed on the back surface mold pressing, in cooperation with the first back-type first sheet-shaped molten resin a predetermined A first surface mold having a convex portion that can be fitted in a concave portion of the first back mold, and a second sheet-like molten resin placed on the second back mold are pressed into a shape. Press-molding the second sheet-like molten resin into a predetermined shape in cooperation with the second back mold ;
A second surface mold having a convex portion that can be fitted into a concave portion of the second back surface mold; and a peripheral portion of each sheet-like molten resin provided and molded on the first surface mold and the second surface mold. Heating means for heating the first back mold and the second back mold, and suppresses the heat transfer to the back mold of the heat accumulated in the peripheral portion of each sheet-like melt-fat to be formed. and thermal insulation means, the ingredients
A molding die for a resin container, comprising: (2) The first sheet-shaped molten resin is mixed with the first back mold and the second
And press-mold it into a predetermined shape.
2 of the sheet-like molten resin and the second back mold and the second front mold
And press molded into a predetermined shape, the first back mold, the second back
The first surface mold and the second surface mold are removed from the surface mold, and the first
The back sheet and the second back sheet are matched to form the first sheet
The peripheral edge of the molten resin and the peripheral edge of the second sheet-shaped molten resin overlap.
Welded to fit it, in the molding method of a resin container, before
During the pressure molding of the first and second sheet-like molten resins,
First and second heating means provided on the first and second surface molds.
While heating the peripheral portion of the sheet-like molten resin of No. 2,
First and second heat insulation means provided on the second back mold
1st, 2nd back surface of the heat of the peripheral part of 2 sheet-like molten resin
The heat transfer to the mold is suppressed, whereby the first and second shells are suppressed.
At the time of superposition welding of the peripheral portion of the molten resin, the first,
Weld the periphery of the second sheet-like molten resin at high temperature
A method for molding a resin container, comprising:

[0007]

According to the present invention, there is provided a mold for a resin container configured as described above, and
In the resin container molding method , the first sheet-like molten resin extruded from the extruder is pressure-molded into a predetermined shape by a first back mold and a first front mold. The second sheet-like molten resin extruded from the extruder is pressure-formed into a predetermined shape by a second back mold and a second front mold.
Thus, since each sheet-like molten resin is compression-molded by the back surface type and the front surface type, it is possible to make the resin container uniform in thickness.

[0008] Since the first surface mold and the second surface mold are provided with heating means, the peripheral portion is heated by the heating means during pressure molding, and heat is sufficiently accumulated in the peripheral portion. Is done. When the molding of the first sheet-like molten resin and the second sheet-like molten resin is completed by the pressing of the first surface mold and the second surface mold, the first surface mold and the second surface mold retreat. The mold matching between the first back mold and the second back mold is performed.

Heat insulation means are provided on the first back mold and the second back mold, respectively, so that heat accumulated in the peripheral portion of each sheet-like molten resin to be formed is prevented from being transferred to the back mold. Is done. Therefore, the peripheral portion can be welded at a high temperature, and the joining strength and airtightness of the peripheral portion can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a mold and a mold for a resin container according to the present invention will be described.
A preferred embodiment of a method for molding a resin container will be described with reference to the drawings.

FIG. 1 to FIG. 6 show an embodiment of the present invention, and particularly show a case where the present invention is applied to a fuel tank made of resin. In FIG. 2, reference numeral 1 denotes an extruder. A molten resin is extruded from the extruder 1. The extruder 1 is guided by a guide rail (not shown), and is movable in the horizontal direction.

A first back mold 2 and a second back mold 3 are arranged near the extruder 1. In the first back mold 2,
A recess 2a is formed. The second back mold 3 has a recess 3a. An arm 4 is attached to a side surface of the first back mold 2. An arm 5 is attached to a side surface of the second back mold 3.

The arm 4 and the arm 5 are connected via a connecting pin 6. A reversing device (not shown) is connected to the second back mold 3. The second back mold 3 is rotatable around the connecting pin 6 by a reversing device. When the second back mold 3 is completely inverted by the reversing device, the first back mold 2 and the second back mold 3 are matched.

Above the first back mold 2, a first front mold 11 is arranged. On the lower surface side of the first front mold 11, a convex portion 11a that can be fitted with the concave portion 2a of the first back mold 2 is provided.
Are formed. The first surface mold 11 can be moved up and down by a lifting means (not shown). Above the second back mold 3, a second front mold 12 is arranged. On the lower surface side of the second front mold 12, the concave portion 3 of the second back mold 3 is provided.
The convex portion 12a that can be fitted with a is formed. The second surface die 12 can be moved up and down by elevating means (not shown).

The first sheet-shaped molten resin 21 extruded from the extruder 1 is placed on the concave portion 2a of the first back mold 2 and the flat portion 2b connected to the concave portion 2a. The flat portion 2b of the first back mold 2 is a portion where a peripheral portion 21a as a joining portion is formed on the first sheet-like molten resin 21.

The second sheet-like molten resin 22 extruded from the extruder 1 is placed on the concave portion 3a of the second back mold 3 and the flat portion 3b connected to the concave portion 3a. The flat part 3b of the second back mold 3 is a part for forming a peripheral part 22a as a bonding part on the second sheet-like molten resin 22.

A portion (nest) 2c of the first back mold 2 for forming the peripheral portion 21a of the first sheet-like molten resin 21.
Is provided with a heating means 31 for forcibly heating the peripheral portion 21a. A part (nesting) for forming the peripheral portion 22a of the first sheet-like molten resin 22 in the second backside shape 3.
3c includes a heating means 3 for forcibly heating the peripheral portion 22a.
2 are provided. Heat insulating materials 33 and 34 are provided on the outer periphery of the inserts 2c and 3c, respectively.

The heating means 31 and 32 are constituted by, for example, electric heaters (cartridge heaters). The electric heater is controlled by a control device (not shown), so that the formed peripheral portions 21a and 22a are heated at an appropriate temperature.

The flat portion 2b of the first back mold 2, which forms the peripheral portion 21a, is provided with a heat insulating means 35 for suppressing the transfer of heat accumulated in the peripheral portion 21a to the first back mold 2. ing. In the flat portion 3b of the second back mold 3, which forms the peripheral portion 22a, there is provided a heat insulating means 36 for suppressing the transfer of heat accumulated in the peripheral portion 22a to the second back mold 3. The heat insulating means 35 and 36 are made of a material having a low thermal conductivity, for example, Teflon resin, ceramic or the like.

A plurality of clips 40 are provided on the side surface of the second back mold 3. The clip 40 is urged toward the side surface of the second back mold 3 by a torsion coil spring (not shown). The clip 40 presses the outer end of the second sheet-like molten resin 22 placed on the second back mold 3. Thus, the second sheet-shaped molten resin 22 does not fall off even if the second back surface shape 3 is inverted.

Next, a molding procedure (molding method) of the resin container.
The operation of the mold will be described. As shown in FIG. 1, the extruder 1 moves above the first back mold 2, and a high-temperature first sheet-like molten resin 21 is extruded from the extruder 1 toward the upper surface side of the first back mold 2. Extruded. The first sheet-shaped molten resin 21 is extruded according to the size of the first back mold 2 and is placed at a predetermined position on the first back mold 2.

Next, the extruder 1 moves toward the second back mold 3, and the high-temperature second sheet-like molten resin 22 is extruded from the extruder 1 toward the upper surface of the second back mold 3. It is.
The second sheet-shaped molten resin 22 is extruded according to the size of the second back mold 3 and is placed at a predetermined position on the second back mold 3.

Each sheet-shaped molten resin 2 is placed on each of the back molds 2 and 3.
When the first and second molds 1 and 22 are placed, as shown in FIG. 2, the first surface mold 11 and the second surface mold 12 are lowered, and the sheet-like molten resins 21 and 22 are pressed by the respective surface molds 11 and 12. Is done. Thus, the first sheet-like molten resin 21 and the second sheet-like molten resin 22 are compression-molded into a predetermined shape. In this state, as shown in FIG. 3, the first sheet-like molten resin 21 and the second sheet-like molten resin 22 are formed with peripheral portions 21a and 22a as joints.

Since the first surface mold 11 and the second surface mold 12 are provided with heating means 31 and 32, the peripheral parts 21a and 22 are heated by the heating means 31 and 32 during compression molding.
is heated, and a large amount of heat is accumulated in the peripheral portions 21a and 22a. Since the first back mold 2 and the first back mold 3 are provided with the heat insulating means 35 and 36, the heat accumulated in the peripheral portions 35 and 36 is transmitted to the respective back molds 35 and 36. Heat is suppressed.

When the first sheet-like molten resin 21 and the second sheet-like molten resin 22 are molded into a predetermined shape, the first surface mold 11 and the second surface mold 12 rise, and the first surface mold 11 and the second surface mold 12 rise. The front mold 11 and the second front mold 12 are removed from the first back mold 2 and the second back mold 3. When the retreat of each front mold 11 and 12 is confirmed, as shown in FIG.
Are reversed by a reversing device (not shown), and the first back mold 2 and the second back mold 3 are matched.

In the state where the first back mold 2 and the second back mold 3 have been matched, as shown in FIG. 5, the peripheral portion 21a of the first sheet-like molten resin 21 and the second The peripheral portion 22a of the sheet-like molten resin 22 is overlapped with the peripheral portion 22a.
1a and the peripheral edge portion 22a are welded. Here, each peripheral part 21a, 22a is provided with a heat insulating means 35 having a small thermal conductivity.
36 so that each peripheral portion 21
The amount of heat transfer of the a and 22a to the back molds 2 and 3 is suppressed, and the peripheral portions 21a and 22a can be welded at a high temperature.

FIG. 6 shows the case where the heat insulating means 35 and 36 are used and the case where the heat insulating means is not used.
2 shows a tensile strength of 2a. As shown in FIG. 6, when the portions of the back molds 2 and 3 that are in contact with the peripheral portions 21a and 22a are iron (Fe), which is the material of the mold itself, it becomes difficult to weld the peripheral portions in a high temperature state. , The tensile strength decreases. When Teflon or the like is used as the heat insulating means as in the present embodiment, the peripheral portions 21a and 22a can be welded at a high temperature, the tensile strength increases, and the airtightness increases.

When the peripheral portions 21a and 22a are welded, air is pressure-fed through the nozzle 15 to the inside of the clamped first back mold 2 and second back mold 3. As a result, each of the sheet-like molten resins 21 and 22 is
And the concave portion 3a of the second back mold 3,
Each sheet-like molten resin 21, 22 is cooled by heat exchange with each back mold 2, 3.

When the molded sheet-like molten resins 21 and 22 are cooled and solidified, the first back mold 2 and the second back mold 3 are opened by the reversing operation of the second back mold 3, The resin fuel tank, which is a molded product, is taken out. When the removal of the fuel tank is completed, the state is returned to the state shown in FIG. 1 and the extruder 1 starts extruding the molten resin again.

[0030]

According to the first aspect of the present invention, there is provided a mold for forming a resin container.
According to the resin container molding method , the following effects can be obtained.

(1) The first sheet-like molten resin extruded from the extruder is compression-molded with a first back mold and a first front mold, and the second sheet-like molten resin is molded into a second back mold. And the second surface mold, the thickness of the resin container can be made uniform as compared with the blow molding, and the quality of the resin container can be improved.

(2) Since the first surface mold and the second surface mold are provided with heating means, and the first back mold and the second back mold are provided with heat insulating means, each sheet-like molten resin is provided with a heating means. During molding, the peripheral part can be heated, and at the time of joining the peripheral part, the heat accumulated in the peripheral part can be suppressed from transferring to the back mold, and the peripheral part can be welded at a high temperature. Become. Therefore, the peripheral portion can be reliably welded, and the joining strength and airtightness of the peripheral portion can be increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state immediately after the start of a molding operation using a molding die for a resin container according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which a sheet-like molten resin is placed on each back mold of the apparatus of FIG.

FIG. 3 is a cross-sectional view showing a state in which a sheet molten resin is pressure-formed by each surface mold and each back mold of the apparatus of FIG. 1;

FIG. 4 is a cross-sectional view showing an inverted state of the second back type shown in FIG. 3;

FIG. 5 is a cross-sectional view showing a state where each back mold is matched by the reversing operation shown in FIG. 4;

FIG. 6 is a characteristic diagram showing tensile strength of a joint due to a heat insulating effect when heat insulating means is provided in each back mold of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extruder 2 1st back mold 3 2nd back mold 11 1st surface mold 12 2nd surface mold 21 1st sheet-shaped molten resin 21a Peripheral part 22 2nd sheet-shaped molten resin 22a Peripheral part 31 Heating means 32 Heating means 35 Heat insulation means 36 Heat insulation means

Claims (2)

(57) [Claims] A first back mold having a concave portion on which a first sheet-like molten resin extruded from an extruder is placed ; and a first back mold rotatably connected to the first back mold; A concave portion is formed, which is configured to be able to be matched with the backside mold of the above, and on which the second sheet-like molten resin extruded from the extruder is placed.
A second back mold that is, the first of the first sheet-like molten resin placed on the back surface mold pressing, in cooperation with the first back-type first sheet-shaped molten resin a predetermined Of the first back side mold
A first surface mold having a convex portion that can be fitted into the concave portion, and a second sheet-like molten resin placed on the second back surface shape are pressed, and a second surface mold is formed in cooperation with the second back surface mold. Press molding the sheet-like molten resin into a predetermined shape .
A second surface mold having a convex portion that can be fitted into the concave portion; heating means provided on the first surface mold and the second surface mold for heating a peripheral portion of each sheet-like molten resin to be molded; A heat insulating means provided in the first back mold and the second back mold, for suppressing heat transfer to the back mold of heat accumulated in the peripheral portion of each sheet-like melt-fat to be formed; A molding die for a resin container. 2. A method according to claim 1, wherein the first sheet-like molten resin is formed into a first back mold.
And press-molded into a predetermined shape
Next, the second sheet-shaped molten resin is supplied to the second back mold and the second table.
Pressure molding into a predetermined shape by sandwiching the
Retreating the first front mold and the second front mold from the second back mold,
The first back mold and the second back mold are matched to form a first sheet.
Peripheral portion of molten resin and peripheral edge of second sheet-shaped molten resin
In the resin container molding method where the parts are overlapped and welded
hand, During the pressure molding of the first and second sheet-like molten resins,
First and second heating means provided on the first and second surface molds.
While heating the peripheral portion of the sheet-like molten resin of No. 2,
First and second heat insulation means provided on the second back mold
1st, 2nd back surface of the heat of the peripheral part of 2 sheet-like molten resin
The heat transfer to the mold, The first and second systems
At the time of superposition welding of the peripheral portion of the molten resin, the first,
Weld the periphery of the second sheet-like molten resin at high temperature
A method for molding a resin container, comprising: