JPH06182797A - Molding method for tubular vessel - Google Patents

Abstract

PURPOSE:To mold a section of a tubular vessel in an irregular shape only by injection molding the vessel. CONSTITUTION:Synthetic resin is injected in a cavity 42 partitioned in an injection mold to mold a tubular vessel, and the cavity 42 is evacuated simultaneously upon injecting to mold the vessel. Melted resin injected by evacuations 43, 44 of the air in the cavity 42 smoothly flows in the cavity 42. After the molding, the air is injected from an injection port 38 between an inner periphery of the molded vessel and a core block 30 in the mold to improve releasability of the tube from the mold, and the molded vessel is removed from the mold.

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
The container body 51 and the mouth portion 52 are separately molded in the manufacturing process. That is, a pipe is first formed by extrusion molding, and this pipe is cut to form the container body 51.

Next, the container body 51 is inserted into an injection molding die. This injection molding die has a cavity for molding only the mouth portion 52 of the tube container 50, and the synthetic resin that has been heated and melted is injected into this cavity, and the mouth portion 52 is opened by the fusion heat. It is heat-fused and integrated into one. Therefore, the conventional tube container has a heat-sealing surface 53.
have.

The manufacturing method of the tube container 50 requires a pipe die, an extruder, an injection mold and an injection mold, and the number of steps for this molding is at least 2.
Since there are many processes, the cost becomes high. 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,
Only cylinders or elliptical shapes (cylinders at the time of molding) are used, and those with irregular cross sections are not used.

[0006]

The present invention has been invented in the above technical background, and achieves the following objects.

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.

A first means of the present invention is, in a method of molding a synthetic resin tube container, a first cavity partitioned in a first injection molding die for molding the tube container, and the first cavity. The first synthetic resin is injected into the core cavity, which is provided in the injection molding die and is the internal space of the tube container, and the first cavity, and at the same time as this injection, the air in the first cavity is sucked to suck the air. After molding the tube container, air is jetted out at least between the inner peripheral surface of the injection-molded tube container and the core block in the injection-molding die so that the injection-molded tube container is A method for molding a tube container is characterized in that the tube container is taken out from an injection molding die.

A second means of the present invention is, in a method of molding a synthetic resin tube container, a first cavity partitioned in a first injection mold for molding the tube container, and the first cavity. The first synthetic resin is injected into the core cavity, which is provided in the injection molding die and is the internal space of the tube container, and the first cavity, and at the same time as this injection, the air in the first cavity is sucked to suck the air. After molding the tube container, the tube container is inserted into a second injection mold different from the first injection mold, and an inner peripheral surface or an outer peripheral surface of the tube container is provided between the tube container and the first injection mold. A second cavity for integrally molding a second layer into a layer by heat-sealing a second synthetic resin different from the first synthetic resin is divided into the second injection mold, and the second cavity is divided into the second cavity and the second cavity. The second A synthetic resin is injected, and at the same time as the injection, the air of the second cavity is sucked to form a laminated tube container, and at least the inner peripheral surface of the injection-molded laminated tube container and the inside of the second injection mold. In the method for molding a tube container, the injection-molded laminate tube container is taken out from the second injection mold by ejecting air between the core tube and the core block.

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 at the same time as this injection, the air in the cavity is sucked to mold the tube container. The molten resin injected by sucking the air in the cavity smoothly flows in the cavity.

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 the movable side of the injection molding die along the guide pin 4. The guide pin 4 is positioned and held by the fixed guide bush 5 and the movable guide bush 43. A cooling water pipe 6 for temperature adjustment is arranged on the fixed-side template 3 so as to surround the outer periphery 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 at the center of the stationary mold plate 3. Furthermore,
At one end of the first cavity plate 7, a second cavity plate 8 for molding the mouth 52 of the tube container is integrally or movably arranged (for die cutting) 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. Further, two runners 23 and a gate 24 are provided. This runner 23
Is supplied with molten resin from a nozzle of an injection molding machine through a sprue (not shown).

On the other hand, a core block 30 is inserted in the central portion of the second cavity plate 7 for molding the tube container body 51. A core pin 31 is fixed to the center of the core block 30. For this fixing, the rear end of the core pin 31 is fixed to the core pin holding plate 32 by the fixing nut 3
It is fixed by 3. 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 at the core block 30.
Has a tapered tip and is inserted into the tapered hole 36 of the core block 30. At the tip of the core pin 31,
A tapered hole 37 is provided, and the pin 22 is inserted into the tapered hole 37 at the time of molding so as 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.
The air ejection hole 38 is connected to the air supply port 4 via the air supply passage 39.
Air is supplied from 0. An O-ring 41 for preventing air leakage is provided between the core pin 31 and the core block 30.
Are 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.

On the outer periphery of the core flock 30 at the rear end of the cavity 42 for molding the tube container body 51,
An air suction passage 43 having a semicircular cross section is formed for air suction. 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 can suck the air in the cavity 42 through the air suction passage 43 and the air suction port 44.

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. The molten resin is first injected at one end of the cavity 42 to mold the mouth of the tube container.

At this time, the cavity 42 is moved by the air suction pump through the air suction passage 43 and the air suction port 44.
Aspirate the air inside. Therefore, the molten resin injected into the mouth of the tube container easily flows in the direction of the cavity 42 of the tube container body. Therefore, the molten resin smoothly flows in the cavity 42, and the cavity 42
To fill. 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.

By the movement of the movable side mounting plate 35, the movable members integrally provided on the movable side mounting plate 35, that is, the spacer 47, the movable side mold plate 46, the stopper plate 45, the core block 30, and the air pin 31 are separated 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). The second injection mold has the same structure and function as the injection mold, but the cavities of the parts to be laminated are defined.

The tube container injection-molded by the injection-molding die is inserted into the second injection-molding die, and the resin to be laminated is molded by the same method as in the above-mentioned embodiment. 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. The laminated resin is heat-fused to the resin that is molded first to be integrally formed. This molding method is not limited to two-layer molding, and any number of layers can be formed.

[0032]

Other Embodiments In the above embodiment, air is introduced between the core block 30 and the molded tube container in order to smoothly release the tube container from the core block 30 and the molded tube container. I am letting you. 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, it may be supplied between the tube container, the cavity plate 7 and the tube container. Further, the positions of the gate and the suction are not limited to those in the above 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, in the tube container forming method, the tube body of the above-mentioned embodiment has a cylindrical main body section, but as shown in FIG. An octagonal tube container 60 can also be molded. In the case of the irregular cross section such as an octagon, positioning protrusions (not shown) such as ribs are formed on the inner peripheral surface of the tube container 60.
To mold. 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. Further, 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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location // B29L 23:20 4F

Claims (3)

[Claims] 1. A method of molding a synthetic resin tube container, comprising: a first cavity partitioned in a first injection mold to mold 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 of forming a tube container, which is characterized by 2. A method of molding a tube container made of synthetic resin, 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, 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.
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 this injection, air of the second cavity is sucked and laminated. After molding the tube container, at least at least the inner peripheral surface of the injection-molded laminated tube container and the core block in the second injection-molding die are blown with air to inject 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.