JPS6233622A - Method and apparatus for molding plastic hollow container - Google Patents

Abstract

PURPOSE:To shorten a molding cycle and to enhance manufacturing efficiency, by receiving a preform in a heating mold while together recirculating the heating mold and a cooling mold to thermally set the same and subsequently transferring said preform to the cooling mold to cool the same. CONSTITUTION:The preform P heated to proper temp. by a heating wheel 1 ppasses through a uniform-heating wheels 4, 4' to make the inner and outer surface temps. thereof uniform and inserted only in a heating mold 7 by a transfer wheel 5 and undergoes biaxial stretching molding and heat setting by a stretching rod and a pressurized fluid. When the heating mold reaches the position of a transfer wheel 9 for transferring a molding while successively rotating, a hollow container is taked out from the mold 7 to be inserted in a cooling mold 8 which is, in turn, cooled under continuous rotation by blowing a pressurized fluid in said mold 8 and the hollow container W is taken out by a transfer wheel 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for molding a plastic hollow container by biaxially stretching a thermoplastic resin such as polyethylene terephthalate. (heat cera by heating deeply for a certain period of time)? The present invention relates to a cooling method and apparatus for a plastic container molding method.

Prior Art When molding containers such as hollow bottles from thermoplastic resins such as polyethylene terephthalate, polyethylene, and polypropylene, the physical and mechanical properties are It is common to perform biaxial stretching to improve the quality of the film. However, plastic containers obtained by biaxial stretching have poor thermal stability, and if coffee, juice, etc. are filled immediately after high-temperature sterilization, the bottle will be heated by the filled contents and become soft and shrink. I wake up. In order to prevent this, conventionally, after molding, heat setting is performed by heating and holding at a constant temperature in the mold for a certain period of time.

In the conventional bottle molding method in which heat setting is performed in the mold, a parison heated to a stretching temperature is inserted into a blow mold that has been heated to a predetermined temperature in advance, and biaxially stretched molding is performed. When the bottle is stretch-molded, the side wall of the bottle is brought into close contact with the inner surface of the mold by the pressurized fluid of blow molding, and the internal pressure is maintained for a certain period of time to heat set the side wall of the bottle to the temperature of the inner wall of the mold. Subsequently, a cooling fluid is circulated inside the bottle or the mold is rapidly cooled to a temperature at which the bottle can be taken out, and then the mold is fully opened and taken out.

Problems to be Solved by the Invention In the conventional method described above, it is necessary to raise the temperature of the mold for heat setting, and on the other hand, after heat setting, the mold must be cooled to a temperature that can be removed without deformation. Therefore, after heat setting, it was necessary to completely drain the pressurized fluid and supply a cooling fluid instead, which lengthened the molding cycle time and reduced production efficiency.

The present invention was devised in view of the above-mentioned circumstances, and provides a novel method and apparatus for reducing cooling time and increasing production efficiency by separating gold into those for heating and those for cooling. The purpose is to

Means for Solving the Problems In the first invention, a heating mold and a cooling mold are circulated together, a heating mold is received therein, a preform is formed by biaxial stretching, and then a preform is formed into a predetermined shape. The hollow container immediately after heat setting is transferred from the heating mold to the cooling mold, and the side wall of the container is heated to the inside of the mold by pressurized fluid in the cooling mold. Next, let it cool by placing it in close contact with it.

The second invention is an apparatus for carrying out the first invention, and in the invention, a blow wheel 6 that is rotationally driven is provided with a heating device for biaxially stretching and heat setting the preform Pft. Several KiII molds 7 and cooling molds 8 for cooling the hollow container after heat setting were arranged alternately. Then, around the blow wheel 6, (a transfer wheel 5 for inserting the preform into the heating mold 7), a transfer wheel 9 for transferring the hollow container from the heating mold 7 to the cooling mold 8, (and A transfer wheel (//) for taking out the hollow container after cooling from the cooling mold 8 was arranged respectively.

The preform P heated to an appropriate operating temperature is inserted into a heating mold using a transfer wheel 5, biaxially stretched in the heating mold 7, and then held under pressure for a predetermined period of time for heat setting. When the heating mold reaches the transfer location by the rotation of the blow wheel 6, the hollow container after heating is transferred to the transfer wheel 9 from the heating mold 7 and transferred to the subsequent cooling mold 8. insert. The container is rapidly cooled by blowing pressurized fluid into the cooling mold to bring the side wall of the container into close contact with the inner surface of the mold.

The cooled container is removed from the cooling mold by means of a transfer wheel 9.

EXAMPLES Hereinafter, the apparatus of the present invention and the molding method for molding hollow bottles will be explained in detail based on the examples shown in the drawings.

In the figure, reference numeral 1 denotes a heating wheel for the preform, and holding parts 2 for receiving and rotatably holding the mandrel supporting the preform are arranged on its circumferential surface at equal intervals. The 7-ohm P is heated by a heater 3 disposed around it while rotating as the heating wheel rotates. 4.4' is a soaking wheel which constitutes a region for equalizing the temperature variation of the preform, which is provided following the heating wheel, and on its surface, like the heating wheel, lCf1 holding portions are arranged at equal intervals. It is arranged so that the preform can be transported. 5 is a blow molding mold 7 for a soaking wheel 4' and a blow wheel 6.
It is a conveyor wheel that relays between

Reference numeral 6 denotes a blow wheel which constitutes the main part of the present invention, and a heating mold for stretching the preform ftZ-axis and heat setting it on the circumference thereof;
, Yugawaeya, 5゜ all the receivers are put in and the cooling metal for cooling is placed in multiple ICs alternately! It is rotated by a drive source (not shown). The heating mold 7 is always at a predetermined temperature VC.
(varies depending on the type of molding material, etc.)
Within the mold, the preform is biaxially stretched and molded using a stretching iron and pressurized fluid. After molding, the internal pressure is maintained for a certain period of time and the bottle side wall is heat set by the temperature of the inner wall of the mold. The cooling mold 8 maintains a temperature (approximately 70°C) that is 1 degree different from the temperature of the heating mold 7 and receives the bottle from the heating mold 7. Pressurized fluid is blown into the bottle to bring the side wall of the bottle into close contact with the inner surface of the mold for rapid cooling.

In this actual weaving example, the biaxial stretching and heat setting process in the heating mold 7 is performed during approximately one revolution of the blow wheel 6, and the cooling mold 8 is used in the next approximately one revolution. It is supposed to be done. However, the invention is not limited to this, and various embodiments may be used, such as performing biaxial stretching and heat setting in the heating mold 7 in half a rotation, and performing a cooling process in the cooling mold 8 in the remaining half rotation. Conceivable.

Alternatively, the heating mold 7 may have an intermediate shape and be used as a primary molding mold, and the cooling mold 8 may have a final bottle shape and be used as a secondary molding mold.

Next, the means for transferring the bottle from the heating mold 7 to the cooling mold 8 and the means for taking out the bottle from the cooling mold 8 will be explained.

A transfer wheel 9 for transferring bottles includes a transfer wheel 11 that takes out bottles from a cooling mold 8 and a heating mold 7.
It is provided in the middle of the transfer wheel 5 into which the hepliform is inserted.

The number of transfer levers 10 of the transfer wheel 5 is set to an odd number, and when the transfer levers 10 rotate each metal in synchronization with the pitch between them, the transfer levers 10 from the heating mold will The cooling molds can be supplied alternately and sequentially.

In the illustrated embodiment, the number of transfer levers 10 is set to three, but if you want to transfer in a short time, use one, and if you want to transfer for a long time, you can increase the number of transfer levers 10. .

The transfer wheel 11 rotates so that the pitch between the transfer levers 12 is equal to the pitch between the cooling molds, and the transfer wheel 11 receives the hollow container W formed from the cooling mold 8 and transfers it to the supply/discharge wheel. It is scheduled to be handed over on the 15th.

In the figure, 17 is a conveyor for discharging the hollow bolt from the molding machine, 18 is a star wheel that receives the preform P from the chute 19 and supplies it to the supply/discharge wheel 15, and 16 is the supply/discharge wheel and the heating wheel 1. This is a conveyance wheel that relays between

With the structure described above, the preform heated to an appropriate temperature by the heating wheel 1 passes through the soaking wheel 4.4, so that the temperature of the inner and outer surfaces becomes uniform, and the preform is transferred from the soaking wheel 4'. It is inserted only into the heating mold by the wheel 5. The heating mold into which the 7-ohm yellow wire was inserted was immediately closed, and the heating mold was biaxially stretched and heat set using a stretching iron and pressurized fluid.The heating mold continued to rotate, and the transfer wheel 11 was installed. The mold opens and continues to rotate with the internal pressure fully released or with some internal pressure maintained near the
When the hollow container reaches the transfer wheel 9 for transfer, the conveyor wheel 9 passes the device consisting of the mold 7, and then the preform P is supplied again to the initial position by the transfer wheel 5, and the same goes on. Repeat the process.

On the other hand, the transfer wheel 9 that sucked out the heat-set hollow bottle moves to the rear cooling mold 8 depending on the number of levers.
Insert the hollow container into the container, take it out in the same way, and repeat the insertion operation. After the bottle is inserted, the supercooling mold 8 immediately closes the mold, and pressurized fluid is blown into the hollow bottle again, causing the side wall of the container to come into close contact with the inner surface of the mold, which is kept at room temperature, and cooling. While continuing to rotate, the internal pressure is released before the discharge transfer wheel 11, and the mold is fully opened. Thereafter, the hollow container W formed by the transfer wheel 11 is taken out and discharged to the conveyor 17 via the supply/discharge wheel 15. The cooling mold from which the hollow bottle was taken out is transferred to the transfer wheel 9, and the hollow bottle immediately after heat setting is inserted again, and the same process is repeated thereafter.

Effects Since the present invention is configured as described above, it has the following remarkable effects.

1) Separate heating and cooling molds allow rapid cooling with the cooling mold immediately after heat setting, reducing cooling time compared to conventional methods and dramatically increasing production efficiency. improved.

+n Since the heating mold is constantly heated without repeating heating and cooling as in the conventional method, there is no waste of energy and it is economical.

111) Since the hollow container is brought into close contact with the inner surface of the mold using pressurized fluid again within the cooling mold, especially in the case of a hollow container with a pattern of protrusions and recesses, the pattern is clearly formed.

IV) Since the cooling mold and the heating mold are arranged alternately, the hollow container can be transferred between the heating mold and the cooling mold in a short time. In addition, in the case of molding that does not require heat setting, all molds are converted to or replaced with regular molds, the transfer wheel 90 function is stopped, and the rotation speed of the transfer wheels 9 and 11 is changed so that all molds are Can be molded into regular containers. .

[Brief explanation of drawings]

The drawing is a schematic front view of a plastic container forming apparatus according to the present invention. 1: Heating wheel 3: Heater 4.4': Soaking wheel 5.9.11: Transfer wheel 6: Blow wheel 7: Heating mold 8: Cooling mold Patent applicant Toyo Seikan Co., Ltd. Applicant representative Patent attorney Aya Sato Procedural amendment (spontaneous) September 13, 1985 Director General of the Patent Office Michibe Uga 1, Indication of the case 1985 Patent Application No. 173165 2, Name of the invention Plastic hollow container Molding method and its device 3, and its relationship to the case of the person making the amendment Patent applicant address 1-3-1 Uchisaiwai-cho, Chiyoda-ku, Tokyo Name
(376) Toyo Seikan Co., Ltd. Representative Yoshibe Takasaki 4, Agent 5 Number of inventions increased by amendment None 6, “Claims” and “Detailed Description of the Invention” of the specification to be amended
Column 7, Contents of amendment 1) The scope of claims is corrected as shown in the attached sheet. 2) “(The heating 1
12, transfer wheel 5, )” and “(and the cooling 111, transfer wheel 11)” described in lines 15 to 17 of the same page. 1) Blow a preform heated to a stretch forming temperature. In a method of forming a hollow container by molding, a heating mold and a cooling mold are arranged on a rotationally driven blow wheel, and a preform is biaxially stretched within the heating mold to form a hollow container. After that, the pressure is maintained for a predetermined period of time, the outer wall of the hollow container is brought into close contact with the inner wall of the heating mold by the pressurized fluid, and heat set is performed, and then the pressurized fluid inside the hollow body is completely evacuated or partially evacuated. While maintaining the pressure, the container is transferred to the cooling mold, and cooled in the cooling mold by bringing the outer wall of the hollow container into close contact with the inner wall of the cooling mold using a pressurized fluid. Molding method for plastic hollow containers 6 2) A heating mold for molding a hollow container by biaxial stretching and heat setting, and a cooling mold for cooling the hollow container after heat setting are installed on a rotationally driven blow wheel. A plastic hollow container molding apparatus, characterized in that a plurality of the blow wheels are arranged alternately and a transfer wheel is arranged around the blow wheel to transfer the hollow container from the heating mold to the cooling mold.

Claims (1)

[Claims] 1) In a method for forming a hollow container by blow molding a preform heated to a stretch forming temperature, a heating mold and a cooling mold are disposed on a rotationally driven blow wheel, and the The preform is biaxially stretched in a heating mold to form a hollow container, which is then held under pressure for a predetermined period of time, and heated by bringing the outer wall of the hollow container into close contact with the inner wall of the heating mold using a pressurized fluid. After that, the pressurized fluid in the hollow body is completely evacuated or a part of the pressure is kept, and then transferred to the cooling mold, and in the cooling mold, the hollow container is refilled with the pressurized fluid. A method for molding hollow plastic containers characterized by cooling by bringing the outer wall into close contact with the inner wall of a cooling mold. 2) A plurality of heating molds for forming and heat-setting a hollow container by biaxial stretching and cooling molds for cooling the hollow container after heat-setting are arranged alternately on a rotationally driven blowwheel, A plastic hollow container molding apparatus characterized in that a transfer wheel for transferring the hollow container from the heating mold to the cooling mold is disposed around the blow wheel.