JP2511390B2 - Tube container molding method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a tube container. More specifically, the present invention relates to a method for forming a tube container for filling a pasty or liquid product such as cosmetics, food, or an adhesive.

[0002]

2. Description of the Related Art A tube container is used as a container for filling cosmetics, foods, adhesives and the like. As shown in FIG. 3, the tube container 50 includes a container main body 51 whose cross section of a normal filling portion is a cylindrical portion, and a mouth portion 52 for pushing the container main body 51 with a finger to push out the filling material in the container main body 51. Have. The mouth portion 52 is provided with a lid 55 which is coupled with a screw, a bayonet or the like. Tube container 50
Is manufactured by separately molding the container body 51 and the mouth portion 52. That is, first make a pipe by extrusion molding,
This pipe is cut to make the container body 51.

Next, the container body 51 is inserted into an injection molding die. The injection mold has a cavity for molding only the mouth portion 52 of the tubular container 50, the key
The synthetic resin that has been heated and melted is injected into the cavity , and the mouth portion 52 is thermally fused to the container body 51 by the heat of fusion to be integrated. Therefore, the conventional tube container has the heat-sealing surface 53.

The manufacturing method of this tube container 50 requires a pipe die, an extrusion molding machine, an injection molding die and an injection molding machine , and the number of steps for this molding is at least two steps. The cost is high because there are many. Furthermore, in extrusion molding, the surface roughness of the die is transferred due to the nature of the molding, and the surface of the molded product is streaked. This streak becomes a problem when appearance is important, such as in a cosmetic tube container. A process such as printing is also necessary to hide this line.

Further, in general, in extrusion molding of a profile (profile material) by extrusion molding, it is difficult to apply a certain rule because the extrusion cross section is not regular, and it is difficult to design a die. In practice, it is often manufactured in the form of trial and error. Under these circumstances, the cross section of the container body of the tube container, which requires accurate shape and precise dimensions,
Cylindrical or elliptical shape (during molding cylinder) is employed only the modified cross-section also is given not adopted.

[0006]

BRIEF Problem to be Solved] The present invention has the also been Do based on the above-described technical background, to achieve the following objectives.

An object of the present invention is to provide a method of molding a tube container for molding the tube container only by injection molding.

Another object of the present invention is to provide a method of molding a tube container, which can mold the cross section of the tube container body into an irregular cross section.

[0009]

The present invention adopts the following means in order to achieve the above object.

[0010] The first means of the invention, there is provided a method of molding a synthetic resin tubular container, a first calibration partitioned in the first injection mold for molding the tubular container
A core block, which is an internal space of the tube container and is provided in the first injection molding die;
After injecting the first synthetic resin into the cavity and sucking the air in the first cavity simultaneously with this injection to mold the tube container, at least the inner peripheral surface of the injection-molded tube container and the injection molding metal. A method of molding a tube container, characterized in that air is ejected between the core block in the mold and the injection-molded tube container is taken out from the first injection mold.

[0011] The second means of the invention, there is provided a method of molding a synthetic resin tubular container, a first calibration partitioned in the first injection mold for molding the tubular container
A core block, which is an internal space of the tube container and is provided in the first injection molding die;
The first synthetic resin is injected into the cavity , and at the same time as this injection, the air in the first cavity is sucked to mold the tube container, and then it is inserted into a second injection mold different from the first injection mold. A second synthetic resin different from the first synthetic resin is integrally layered on the inner peripheral surface or the outer peripheral surface of the tube container between the tube container and the first injection mold by heat fusion. A second cavity for molding a layer is divided into the second injection molding die, the second synthetic resin is injected into the second cavity , and at the same time as the injection, the second cavity is injected.
After molding the laminated tube container by sucking air in the cavity , air is jetted out at least between the inner peripheral surface of the injection-molded laminated tube container and the core block in the second injection molding die, A method of molding a tube container, characterized in that the injection-molded laminated tube container is taken out from the second injection mold.

It is further preferable that the cross-section of the container body of the tube container is irregular.

[0013]

In order to mold the tube container, the synthetic resin is injected into the cavity defined in the injection molding die, and simultaneously with this injection, the air in the cavity is sucked to mold the tube container. Air injected molten resin by suction in the cavity will flow through the cavity smoothly.

After this molding, air is ejected between the inner peripheral surface of the injection-molded tube container and the core block in the injection-molding die to improve the releasability between the tube container and the injection-molding die. Then, the injection-molded tube container is taken out from the injection-molding die.

[0015]

First Embodiment A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of an injection mold for injection molding a tube container. The fixed side attachment plate 1 is attached to a fixed plate for fixing an injection mold of an injection molding machine, and a locate ring 2, a fixed side mold plate 3 and the like are integrally attached. Locate ring 2
Is for positioning on the fixed platen.

One end of four guide pins 4 is fixed to the fixed side mounting plate 1. The guide pin 4 is for guiding along the movable side of the injection mold to the guide pin 4. The guide pin 4 is the guide bush 5 on the fixed side.
And it is positioned and held by the variable dynamic side of the guide bush 4 8. The fixed side template 3 has a cooling water pipe 6 for temperature control.
Are arranged so as to surround the outer circumference of the cavity .

The cooling water pipe 6 is for maintaining the injection molding temperature at an optimum level, and is for controlling by making temperature-controlled water flow in the cooling water pipe 6. The structure and function of the temperature control system are well known and will not be described here in detail. A first cavity plate 7 for molding the container body is arranged in the center of the stationary mold plate 3. Further, at one end of the first cavity plate 7, the mouth portion 52 of the tube container is
The second cavity plate 8 for molding is integrally or movably (for die cutting) arranged and fixed.

A gate plate 9 is further arranged and fixed to one end of the second cavity plate 8. The gate plate 9 is integrally provided with a pin 22 for molding the discharge port 54 of the opening 52. The pin 22 is inserted into the tip of the core pin 31 as described later at the time of molding. In addition, two runners 2
3 and a gate 24 are provided. The melted resin is supplied to the runner 23 from a nozzle of the injection molding machine through a sprue (not shown).

On the other hand, the core block 3 is formed at the center of the first cavity plate 7 for molding the tube container body 51.
0 is inserted. At the center of the core block 30,
The core pin 31 is inserted . Core pin 31 is fixed by a fixing nut 33 that <br/> rearmost within core pin holding plate 32. The core pin holding plate 32 is fixed to the movable mounting plate 35 via a spacer 34.

The tip of the core pin 31 is tapered and is inserted into the tapered hole 36 of the core block 30. A taper hole 37 is provided at the tip of the core pin 31, and the pin 22 is inserted into the taper hole 37 at the time of molding to be integrated with the core pin 31, and the pin 22 constitutes a discharge port 54 of the tube container. After all, the core block 30 and the core pin 31 are assembled together to form the main body of the tube container 50.

Between the core block 30 and the core pin 31, air ejection holes 38 are arranged at equal intervals on the circumference.
Air is supplied from the air supply port 40 via the air supply passage 39 to the air ejection holes 38. An O-ring 4 is provided between the core pin 31 and the core block 30 to prevent air leakage.
1 is arranged. The blown air penetrates between the core block 30 and the molded tube container 50, and assists the mold release between the core block 30 and the molded tube container.

A key for molding the tube container body 51.
The outer periphery of the core block 30 at the rear end of Yabiti 42, the cross-sectional shape for the air suction semicircular air suction path 43 is formed. The air suction passage 43 is connected to the air suction pump. The air suction passage 43 communicates with the cavity 42 via the air suction port 44. After all, the air suction pump is operated via the air suction passage 43 and the air suction port 44.
The air in the cavity 42 can be sucked.

On the other hand, a stopper plate 45 is arranged on the movable side of this injection mold so as to contact one end of the fixed mold 3 and fix one end of the core block 30. The stopper plate 45 is a movable mold plate 4
It is fixed integrally to 6. The movable side mold plate 46 is further fixed to the movable side mounting plate 35 via a spacer 47.

Molding Method The injection molding method of the tube container by the above-mentioned injection molding die will be described in detail below.

The molten resin is supplied to the runner 23 and the gate 24 from the nozzle of the injection molding machine through the sprue. This resin is generally selected from resins such as polyethylene, nylon, and vinyl acetate resins that form the tube container. The choice depends on the application of the tube container, i.e. the contents to be filled in the container. Molten resin cavity for initially forming the mouth of the tubular container
It is injected at one end of the tee 42.

At this time, the air in the cavity 42 is sucked through the air suction passage 43 and the air suction port 44 by the air suction pump. Therefore, the molten resin injected into the mouth of the tube container easily flows toward the cavity 42 of the tube container body. Thus the molten resin smoothly flow in the cavity 42, filling the cavity 42. When the filling of the resin is completed, that is, when the molding is completed, a control device (not shown) opens the electromagnetic valve to supply the air to the air ejection hole 38 and supplies the air.

The supplied air is supplied from the air supply port 40, the air supply passage 39 and the air ejection port 38.
The blown air penetrates between the core block 30 and the molded tube container to help the smooth release between the core block 30 and the molded tube container. Then, the injection molding machine moves the movable side mounting plate 35.

[0028] By the movement of the movable side mounting plate 35, a movable member which is provided integrally thereto, i.e. the spacer 47, the movable side mold plate 46, the stopper plate 45, the core block 30, co Appin 31 away from the fixed side . This movement on the movable side is performed by slidingly guiding the bush 48 by the guide pin 4.

By this movement, when the fixed side and the moving side are completely released from each other, the injection-molded tube container is taken out of the injection-molding die by air, an ejector (not shown) or the like. Since the mouth of the tube container is difficult to release due to the screw structure, the second cavity plate 8 is retracted (not shown).

[0030]

Second Embodiment In the above-mentioned embodiment, although the tube container has a single layer structure, depending on the type of contents to be filled, a gas barrier property for preventing permeation of oxygen and the like may be required.
In this case, a synthetic resin having a high gas barrier property is laminated. This laminating method uses a second injection mold having the same structure as that of the above-mentioned embodiment (not shown). This second injection mold has the same structure and function as the injection mold, but has a cavity defined in a portion to be laminated.

[0031] Insert the tube container is injection molded in the injection mold to a second injection mold in, forming a laminated by <br/> Utosuru resin in Example a similar manner. However, when the tube container is taken out from the first injection mold, it is inserted into the second injection mold without being removed from the core block 30. Laminated resin is configured integrally heat-sealed to said first molded resin.
This molding method is not limited to two-layer molding, and any number of layers can be formed.

[0032]

In [other embodiments] Example, in order to release the tube container formed with the core block 30 to smoothly, by entering between the tube container formed of an air core block 30 There is. However, the supply of air for this mold release is not limited to this, and may be jetted to any part of the injection molding die. For example, the tube container and key
It may be supplied to the cavity board 7. Also the gate,
The position of suction is not limited to the above-mentioned embodiment, but may be changed depending on the shape of the type of the tube container to be molded.

In the above embodiment, the gate is ejected from the mouth 52 side, but it may be ejected from the rear part of the container body 51 through the film gate. At this time, suction of air is performed from the side of the mouth portion 52.

Further, as can be understood from the above description ,
According to the molding method of the present invention, the tube container of the embodiment, the cross section of the container body portion has a cylindrical cross-section as shown in FIG. 2 can be formed even octagonal tubular container 60. In the case of the irregular cross section such as octagon, a positioning protrusion such as a rib (not shown) is formed on the inner peripheral surface of the tube container 60. This projection is used for positioning when printing or the like.

[0035]

As described above in detail, the tube container molding method of the present invention has a small number of molding steps, and the molding machine is only an injection molding machine. Also, the number of molding dies is small. Further, unlike the conventional case, the surface of the tube container is beautiful because there are no lines due to the surface roughness of the die formed by extrusion molding. Furthermore, since there is no restriction on the cross-sectional structure of the tube container, there is a feature that the range of selection is expanded in design.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an injection mold of a first embodiment for injection molding a tube container.

FIG. 2 is an external view showing a molding example of another tube container.

FIG. 3 is a cross-sectional view of a conventional tube container and its screw lid.

[Explanation of symbols]

1 ... Fixed side mounting plate 3 ... 1st cavity plate 4 ... Guide pin 5 ... Guide block 6 ... Water cooling pipe 30 ... Core block 31 ... Core pin 35 ... Movable mounting plate 38 ... Air ejection hole 39 ... Air supply path 40 ... Air supply Port 42 ... Cavity 43 ... Air suction passage 44 ... Air suction port 45 ... Stopper plate 46 ... Movable side template

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Claims (3)

(57) [Claims] 1. A method for molding a synthetic resin tube container, comprising: a first cavity defined in a first injection mold for molding the tube container; and a first cavity provided in the first injection mold. After injecting the first synthetic resin into the core block, which is the internal space of the tube container, and the first cavity, and at the same time as injecting the air in the first cavity to form the tube container, at least Taking out the injection-molded tube container from the first injection mold by ejecting air between the inner peripheral surface of the injection-molded tube container and the core block in the injection-molding mold. A method for forming a tube container, which is 2. A method for molding a synthetic resin tube container, comprising: a first cavity defined in a first injection mold for molding the tube container; and a first cavity provided in the first injection mold. And a core block which is an internal space of the tube container, and a first synthetic resin is injected into the first cavity , and simultaneously with this injection, air in the first cavity is sucked to mold the tube container, The first synthetic resin is inserted into a second injection mold different from the first injection mold, and the first synthetic resin is provided on the inner peripheral surface or the outer peripheral surface of the tube container between the tube container and the first injection mold. The second synthetic resin which is different from the second is integrally layered by heat fusion.
Defines a second cavity for molding the layers into the second injection mold, the second injection the second synthetic resin in the cavity, laminate the injection and by sucking air in the second cavity at the same time After molding the tube container, air is jetted out at least between the inner peripheral surface of the injection-molded laminated tube container and the core block in the second injection molding die, and the injection-molded laminated tube container The second
A method of molding a tube container, characterized by taking out from an injection molding die. 3. The method of molding a tube container according to claim 1, wherein the container body of the tube container has an irregular cross section.