JP2000167915A - Method and apparatus for molding plastic container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve simplification of process, reduction of installation area of equipment, equipment cost, and operation and maintenance cost by a method wherein both of the molding and the sterilizing of a plastic container are performed simultaneously without using a cleaning liquid to sterilize the molded plastic container. SOLUTION: A preformed material 4 having a test tube-like shape is set in a blow molding die 15, and the preformed material 4 is stretched by means of a stretching rod 5, following which an ozone gas 24 is blown into the stretched preformed material 4 to inflate it. Thus, a plastic container having an external shape made after the internal surface of the die 15 is molded and at the same time, the internal surface of the plastic container is sterilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a plastic container from a preform material or a parison by using ozone gas so that the plastic container can be formed and sterilized simultaneously. The present invention relates to a molding device.

[0002]

2. Description of the Related Art Plastic containers for storing contents such as foods and pharmaceuticals are molded by high-pressure air, sterilized, and the contents are stored in the plastic containers.

[0003] Conventional plastic container molding,
The procedure of sterilization and storage of contents will be described with reference to FIGS.

That is, a plastic raw material b is injection-molded by an injection molding machine a as shown in FIG. 12 to form a test tube-shaped plastic preform material c as shown in FIG. As shown in FIG. 14, the preform material c is heated to an optimum temperature by a heating device d, and the heated preform material c is set in a blow mold e of a plastic container molding machine as shown in FIG.

Next, from the upper opening of the preform material c,
As shown in FIG. 16, by inserting a biaxial stretching rod f into the preform material c, pressing the lower end of the stretching rod f against the inner bottom of the preform material c, and further lowering the stretching rod f, as shown in FIG. Then, the preform material c is stretched to the bottom of the blow mold e, and a high-pressure air supply source (not shown) is connected to a high-pressure air supply hole formed in the axial center of the stretching rod f, as shown in FIG. Then, high-pressure air g is blown into the preform material c from the lower end of the stretching rod f to expand the preform material c, thereby forming a plastic bottle-shaped plastic container h whose outer shape follows the inner peripheral shape of the blow mold e. .

When the preform material c expands following the inner peripheral shape of the blow mold e to form the plastic container h,
After removing the stretching rod f, the cooling water is circulated through a cooling water hole (not shown) provided in the blow mold e to cool the plastic container h. Thereafter, as shown in FIG. 18, the blow mold e is opened. Remove the plastic container h.

When the plastic container h is taken out of the blow mold e, an empty plastic container h is inspected by a plastic container inspection machine, and then the plastic container h is sterilized by a plastic container sterilizer, and the sterilized plastic container h is sterilized. h is filled with contents such as foods and medicines by a filling machine.

[0008]

When a plastic container h is sterilized by a plastic container sterilizer, a cleaning liquid such as an aqueous hydrogen peroxide solution is conventionally supplied to the molded plastic container h to clean and sterilize the plastic container h. I'm trying to do it. For this reason, after the plastic container h is washed, the washing liquid has to be treated, and a separate washing liquid treatment device is required for this treatment, so that equipment costs and operation and maintenance costs rise.

Further, since the molding of the preform material c into the plastic container h and the washing and sterilization of the molded plastic container h are performed in separate steps, the production line becomes longer and the production equipment is installed. This leads to an increase in the area, and furthermore, a plastic container forming machine and a plastic container washing machine are required, so that the equipment cost and the operation and maintenance cost also rise.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention makes it possible not to use a cleaning liquid for washing and sterilizing plastic containers, and to simultaneously perform molding and sterilization of plastic containers in one step, thereby forming a plastic container. Simplification of the washing and sterilization processes, thereby shortening the production line and simplifying the equipment, so that the equipment installation area can be reduced, and at the same time the equipment costs and operation and maintenance costs can be reduced. It is done for the purpose of doing.

[0011]

According to the method of molding a plastic container of the present invention, a preform material or a parison is set in a blow mold and a rod-like body movable in the blow mold in the axial direction of a stretching rod. The preform material or the parison is stretched, and then the ozone gas is blown into the stretched preform material or the parison to expand the preform material or the parison, thereby forming a plastic container having an outer shape following the inner peripheral surface of the blow mold. At the same time, the inner surface of the plastic container is sterilized.

Further, the apparatus for molding a plastic container according to the present invention is characterized in that an ozone gas is blown into a preform material or a parison set in a blow mold to expand the preform material or the parison, thereby forming the plastic container and forming an inner surface of the plastic container. Is provided with a means for sterilizing.

In the present invention, ozone gas is blown into the stretched preform material or parison, and the preform material or parison expands due to the pressure of the ozone gas to form a plastic container and sterilize the inner surface of the plastic container. Will be

In the present invention, molding and sterilization of a plastic container can be performed in one step by blowing ozone gas into a preform material or a parison.
The cleaning liquid is not required for sterilization, and the treatment of the cleaning liquid is not required. Therefore, the process can be simplified, the production line can be shortened, and the equipment can be simplified. As a result, the installation area of the equipment can be reduced, and the space can be effectively used. Equipment costs and operation and maintenance costs can be reduced.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 10 show an embodiment of the present invention.

FIG. 1 shows a step of molding a preform material by an injection molding machine. In the drawing, reference numeral 1 denotes an injection molding machine; 2, a plastic raw material 3 extruded and molded by the injection molding machine 1; The die 5 in which the preform material 4 is molded is placed in the gap between the die 5 and the hole of the die 2.
Is formed in the hole of the die 2, and 6 is a cooling water passage provided in the die 2 so as to supply cooling water. 4
In order to form the external thread portion 4a at the front end on the opening side, the auxiliary die 2a which is fitted to the extension rod 5 can be fitted inside.

Details of the stretching rod 5 are shown in FIGS. The extension rod 5 includes a hollow cylindrical core 10 having a lower end formed in a substantially hemispherical shape, and a hollow cylindrical extension rod body 11 is provided in a hollow hole of the core 10 by an actuator (not shown). It is fitted so as to be able to move up and down.

An annular gap 12 for venting air is formed between the outer periphery of the core 10 and the elongated rod body 11, and the inner periphery of the hollow hole at the upper and lower ends of the core 10 is planar. A plurality of projections 10a and 10b project radially when viewed from the drawing so as to come into contact with the outer periphery of the elongated rod body 11.

The elongate rod body 11 can be moved up and down by being guided by the projections 10a and 10b of the core 10 when ascending and descending, and air passing through the arc-shaped gap 12b between the projections 10b and 10b. Gas such as rises in the gap 12 and is discharged outside through the arc-shaped gap 12a between the protrusions 10a.

A hollow cylindrical inner pipe 13 is fitted in the hollow hole of the extension rod body 11 so as to be able to move up and down integrally with the extension rod body 11. Thus, the lower end of the inner pipe 13 projects slightly below the lower end of the elongated rod body 11, and when the elongated rod body 11 and the inner pipe 13 are raised to the upper end position, the hemispherical shape of the lower end of the core 10 is formed. At the lower end of the inner pipe 13, a spherical shape having the same radius of curvature as the spherical surface at the lower end of the core 10 is formed so as to smoothly connect to the portion (see FIG. 10).

A gap 14 is formed over the entire circumference of the elongated rod body 11 between the flat portion at the upper end of the spherical portion 13 a at the lower end of the inner pipe 13 and the lower end of the elongated rod body 11. A plurality of ozone gas injection holes 13c are radially viewed in a plan view so that the ozone gas supplied through the hollow hole 13b of the inner pipe 13 can be blown into a plastic container 29 described later. Has been drilled.

FIG. 2 shows a step of heating a preform material formed by injection molding and having a stretched rod fitted therein as it is, and in FIG. 2, numeral 7 denotes a state formed with the stretched rod 5 fitted therein. A heating device such as an infrared heater for heating the preform material 4.

FIG. 3 shows a preform material externally fitted to a stretching rod set in a split blow mold and an auxiliary mold in a plastic container molding machine, and the preform material is heated to a predetermined constant temperature and stretched. In the drawing, reference numeral 15 denotes a two-piece blow mold in which the preform material 4 externally fitted to the stretching rod 5 is set, and 16 denotes a preform material for heating the preform material 4 to a constant temperature. A heating and cooling device provided on the blow mold 15 so as to supply a heating fluid or a cooling fluid for cooling the preform material 4 to a constant temperature.
A cooling fluid supply hole, in which an auxiliary mold 17 which can be externally fitted to the male screw part 4a of the preform material 4 and the upper end of the extension rod 5 can be fitted inside the upper part of the blow mold 15. Has become.

FIG. 4 shows a step of blowing ozone gas into the preform material which has been heated to a predetermined temperature for molding and sterilizing the preform material.
Reference numeral 9 denotes an oxygen generator for extracting oxygen from compressed air supplied by being compressed by the compressor 18, reference numeral 20 denotes an ozone generator for generating ozone gas based on oxygen from the oxygen generator 19, and reference numeral 21 denotes air. It is a blower to send.

Reference numeral 22 denotes an ozone gas supply pipe connected to the outlet side of the ozone generator 20, and reference numeral 23 denotes an air supply pipe connected to the outlet side of the blower 21, which passes through the ejector section 22a from the ozone gas supply pipe 22. Ozone gas 2
The preform material 4 is supplied to the hollow hole 13b of the inner pipe 13 through the conduit 25 by the ejector effect of the air supplied from the blower 21 and passes through the ozone gas injection hole 13c from the hollow hole 13b. It is to be blown in.

Reference numeral 26 denotes an ozone concentration detector connected to the pipe 25, and reference numeral 27 denotes a flow control valve connected to the ozone gas supply pipe 22. The flow control valve corresponds to the ozone concentration detected by the ozone concentration detector 26. The opening of the valve 27 can be adjusted.

Reference numeral 28 denotes an ozone gas 24 for the preform material 4.
When blown into the preform material 4
A gap 12b between the core 10 and the elongated rod body 11;
These gases are discharged to the outside through 12, 12a (see FIGS. 6, 9, 8, and 7).

FIG. 5 shows a step of taking out a plastic container molded and sterilized by blowing ozone gas from a blow mold and an auxiliary mold. In the figure, 29 is a plastic container, and 30 is a support stand.

In FIGS. 1 to 10, the same parts are denoted by the same reference numerals.

Next, a procedure for molding a plastic container by blowing ozone gas into a preform material in the embodiment of the present invention will be described.

First, a molten high-temperature plastic raw material 3 is separated into a die 2 and a die 2 by an injection molding machine 1 shown in FIG.
The extruded material is extruded into a gap between the outer periphery of the elongated rod 5 and the outer periphery of the elongated rod 5 fitted in the hole, thereby forming a test tube-shaped preform material 4.
At this time, a male screw portion 4a for cap fitting is formed at the opening-side tip of the preform material 4 by the auxiliary die 2a which is fitted inside the hole of the die 2 with the extension rod 5 fitted inside. . When the preform material 4 is formed by injection molding, cooling water is supplied to the cooling water passage 6 to cool the preform material 4 to a predetermined temperature.

The preform material 4 formed by injection molding is taken out of the die 2 and the core 10
2 is heated so as to have a predetermined temperature by a heating device 7 shown in FIG. Further, the extending rod body 11 and the inner pipe 13 of the extending rod 5 rise to the uppermost part with respect to the core 10, the upper surface of the spherical portion 13a of the inner pipe 13 contacts the lower end of the core 10, and the lower end of the extending rod 5 It is hemispherical as a whole (see FIG. 10).

The preform material 4 which has been heated to a predetermined temperature while being externally fitted to the stretching rod 5 has a male thread 4a sandwiched between two auxiliary molds 17 as shown in FIG. It is set in a split blow mold 15.

When the preform material 4 is set in the blow mold 15, the extension rod body 11 of the extension rod 5 is lowered integrally with the inner pipe 13 by an actuator (not shown). The spherical portion 13a extends the lower end of the preform material 4 downward (vertically). Therefore, the preform material 4 has a test tube shape longer than the initial state. At this time, the heating fluid is supplied to the heating / cooling fluid supply hole 16 of the blow mold 15 until the molding is completed, and the temperature of the preform material 4 is maintained at a predetermined temperature.

When the preform material 4 is stretched downward,
As shown in FIG. 4, in a state where the spherical portion 13 a of the inner pipe 13 (see FIG. 6) presses the inner bottom of the preform material 4, the conduit 25 is connected to the inner pipe 13 of the extension rod 5, Ozone gas 24 is blown into the reforming material 4.

That is, the compressed air generated by compressing the air introduced into the compressor 18 is sent to an oxygen generator 19 to extract oxygen from the compressed air, and the extracted oxygen is sent to an ozone generator 20. It is sent to become ozone gas,
It is sent to the ozone gas supply pipe 22.

On the other hand, the pressurized air pressurized by the blower 21 is supplied from the air supply pipe 23 to the pipe line 25. At this time, the ozone gas 24 in the ozone gas supply pipe 22 is discharged from the ejector by the pressurized air. By the action, the ozone gas is introduced from the ozone gas supply pipe 22 into the conduit 25, passes through the hollow hole 13 b of the inner pipe 13 from the conduit 25, and passes through the ozone gas injection hole 13 c formed at the distal end of the inner pipe 13, and the preform material passes through It is blown into 4. Therefore, the preform material 4 expands due to the pressure of the ozone gas 24 as shown in FIG.
As shown in FIG. 5, a plastic container 29 having a shape following the inner peripheral surface of the blow mold 15 is formed.

The concentration of the ozone gas 24 passing through the pipe 25 is detected by an ozone concentration detector 26, and the flow control valve 27 is controlled based on the result. For this reason, the concentration of the ozone gas blown into the preform material 4 is controlled to a specified value.

Since the male screw portion 4a of the preform material 4 is sandwiched between the auxiliary mold 17 and the extension rod 5, when the ozone gas 24 is blown into the preform material 4 to form the plastic container 29, the male screw portion 4a is formed. Is not deformed.

Since the inner surface of the preform material 4 is sterilized by the ozone gas 24 when the plastic container 29 is molded, it is not necessary to wash and sterilize the molded plastic container 29 in a later step.

When the ozone gas 24 is blown into the preform material 4, the gas 28 in the preform material 4 is changed into the core 10 of the stretching rod 5 and the stretching rod body 1 with an increase in pressure.
1, gaps 12b, 12, 12a (FIGS. 6, 9, 8,
7) to the outside.

Further, when the ozone gas 24 is blown into the preform material 4, the inner pipe 13 ascends along with the core 10 of the extension rod 5 and the extension rod body 11 in accordance with the expansion of the preform material 4, and the molding is completed. Then, when the lower end of the core 10 is positioned on the inner periphery of the male screw portion 4a of the plastic container 29, the spherical portion 13 at the lower end of the inner pipe 13 is formed.
a upper surface comes into contact with the lower end of the core 10 (FIG. 3,
4, 5, 10).

The core 10 ascends to a predetermined position along with the main body 11 of the drawing rod 5 and the inner pipe 13 and cooling water is supplied to the heating / cooling fluid supply hole 16 to cool the plastic container 29 to a predetermined temperature. When done
The left and right blow molds 15 and the auxiliary mold 17 are separated as shown in FIG. 5, and the plastic container 29 which has been molded and sterilized is taken out from the blow mold 15 and the auxiliary mold 17 and placed on the support base 30. It is air-cooled.

The cooled plastic container 29 is sent to the contents filling step, where the contents such as food and medicine are filled, and then sent to the cap attaching step, where the cap is screwed into the male screw portion 4a.

According to the embodiment of the present invention, the molding and sterilization of the plastic container 29 can be performed in one step by blowing the ozone gas 24 into the preform material 4, so that the cleaning liquid such as the aqueous hydrogen peroxide solution is used. This eliminates the need for post-treatment of the cleaning liquid. Accordingly, the process can be simplified, the production line can be shortened, and the equipment can be simplified. As a result, the installation area of the equipment can be reduced, the space can be effectively used, and the equipment cost can be reduced. In addition, the operation and maintenance cost can be reduced.

FIG. 11 shows another example of the ozone gas blowing step for simultaneously forming and sterilizing the preform material in the embodiment of the present invention.

In this embodiment, the ozone gas 24 generated by the ozone generator 20 is supplied to the ozone gas supply pipe 2 by a pressurizing means (not shown) provided in the ozone generator 20.
2 is blown into the preform material 4 through a hollow hole 13b provided in the inner pipe 13 of the stretching rod 5 and an ozone gas injection hole 13c (see FIG. 6) at the lower end of the inner pipe 13. The molding and sterilization of No. 4 are performed.

Also in this embodiment, the molded plastic container does not need to be washed and sterilized in a later step, so that the same operation and effect as those of the above-described embodiment can be obtained.

Note that, in the embodiment of the present invention,
Although the case of molding a plastic container using a preform material has been described, it is also possible to mold a plastic container using a parison, and other various changes can be made without departing from the spirit of the present invention. thing,
Of course, it is.

[0051]

According to the method and apparatus for molding a plastic container of the present invention, the plastic container can be molded and sterilized in one step, so that a cleaning solution such as an aqueous solution of hydrogen peroxide is not required, and No need for post-processing,
Therefore, the process can be simplified, the production line can be shortened, and at the same time, the equipment can be simplified. As a result,
Various excellent effects can be achieved such that the installation area of the equipment can be reduced, the space can be effectively used, and the cost of equipment and operation and maintenance can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a step of molding a preform material by an injection molding machine in a method and an apparatus for molding a plastic container of the present invention.

FIG. 2 is a vertical cross-sectional view showing a step of heating a preform material molded by injection molding in a state of being externally fitted to a stretch rod in the method and apparatus for molding a plastic container of the present invention.

FIG. 3 shows a method and an apparatus for molding a plastic container according to the present invention, in which a preform material externally fitted to an extension rod is set in a blow mold and an auxiliary mold, and heated to a predetermined constant temperature. It is a longitudinal cross-sectional view which shows the process of extending a preform material with an extending | stretching rod.

FIG. 4 is a longitudinal sectional view showing a step of blowing ozone gas into a preform material in the method and apparatus for molding a plastic container of the present invention.

FIG. 5 is a longitudinal sectional view showing a step of taking out a plastic container molded and sterilized by blowing ozone gas from a blow mold and an auxiliary mold in the method and the apparatus for molding a plastic container of the present invention.

FIG. 6 is a longitudinal sectional view of an example of a stretch rod used in the method and apparatus for molding a plastic container of the present invention.

FIG. 7 is an enlarged view in the direction of arrows VII-VII in FIG. 6;

8 is an enlarged view in the direction of arrows VIII-VIII in FIG. 6;

9 is an enlarged view in the direction of arrows IX-IX in FIG. 6;

FIG. 10 is a longitudinal sectional view of a lower end portion of the extension rod showing a state where the extension rod body and the inner pipe are raised to an upper end position with respect to the core in the extension rod shown in FIG. 6;

FIG. 11 is a longitudinal sectional view showing another example of the step of blowing ozone gas into a preform material in the method and apparatus for molding a plastic container of the present invention.

FIG. 12 is a longitudinal sectional view showing a step of molding a preform material by an injection molding machine in a conventional plastic container molding method.

FIG. 13 is a longitudinal sectional view of a preform material molded by injection molding in a conventional plastic container molding method.

FIG. 14 is a longitudinal sectional view showing a step of heating a preform material in a conventional plastic container molding method.

FIG. 15 is a longitudinal sectional view showing a state in which a preform material is set in a split blow mold in a conventional plastic container molding method.

FIG. 16 is a longitudinal sectional view showing a state in which a preform material is stretched by a stretching rod in a conventional plastic container molding method.

FIG. 17 is a longitudinal sectional view showing a state in which high-pressure air is blown into a preform material to form a plastic bottle in a conventional plastic container molding method.

FIG. 18 is a longitudinal sectional view showing a state in which a molded PET bottle is removed from a blow mold in a conventional plastic container molding method.

[Explanation of symbols]

 Reference Signs List 4 Preform material 5 Stretched rod 11 Stretched rod body (rod) 13 Inner pipe (rod) 15 Blow mold 18 Compressor (means) 19 Oxygen generator (means) 20 Ozone generator (means) 21 Blower (means) 22) Ozone gas supply pipe (means) 22a Ejector section 23 Air supply pipe (means) 24 Ozone gas 25 Pipe line (means) 29 Plastic container

Claims (2)

[Claims] 1. A preform material or parison is set in a blow mold, and the preform material or parison is stretched in a blow mold by a rod-shaped body movable in an axial direction of a stretching rod, and then the stretched preform is formed. A plastic container characterized by blowing ozone gas into a reforming material or parison to expand the preform material or parison to form a plastic container having an outer shape following the inner peripheral surface of a blow mold and sterilizing the inner surface of the plastic container. Molding method. 2. A means for injecting ozone gas into a preform material or a parison set in a blow mold to expand the preform material or the parison to form a plastic container and to sterilize the inner surface of the plastic container. Plastic container molding equipment.