JPS6359366B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for manufacturing a hollow plastic body, and more specifically, the present invention relates to an apparatus for manufacturing a hollow plastic body, and more specifically, a hollow body is manufactured by sequentially injecting plasticized plastic into a plurality of molds arranged on the same circumference. The present invention relates to a manufacturing apparatus for manufacturing hollow plastic bodies.

Conventional manufacturing equipment for plastic hollow bodies, for example, manufacturing equipment for mass producing bottomed injection molded parisons used for blow molding or stretch blow molding using the hot parison method, is known, for example, from Japanese Patent Publication No. 1973-
As disclosed in No. 22096, it is usually equipped with one injection device and one cavity mold having a plurality of cavities arranged in a straight line, and simultaneously produces a plurality of parisons by one injection. It was a type of molding. As a result, the injection device becomes large-sized, and the residence time of the molten resin within the injection device is long, making it easy for the resin to deteriorate. In other words, when the resin is polyethylene terephthalate, harmful acetaldehyde generated by decomposition during retention remains in the final product, blown hollow body or stretched blown hollow body, and the contents thereof (e.g. salad oil, soy sauce, youth There was a problem that it could migrate into liquid foods (such as liquid foods). Further, in the case of polypropylene, problems such as yellowing, decrease in strength, and deterioration of flavor occur easily. Also, since the multiple cavities are arranged in a straight line, the spacing between each cavity and the injection device nozzle is not uniform.
Therefore, the temperature of the resin supplied to each cavity tends to be uneven, and the cooling effect differs depending on the arrangement position of each cavity, so it is difficult to manufacture parisons with uniform physical properties (for example, residual strain). It was difficult.

The present invention has been made in view of the problems of the prior art as described above, and an object of the present invention is to provide a manufacturing apparatus capable of mass-producing plastic hollow bodies of excellent and uniform quality. be.

To achieve the above object, the present invention provides an extrusion device for plasticized plastics, a plurality of cavity molds and a core disposed on the same circumference at the end side of a hot runner manifold connected to a nozzle of the extrusion device. A mold having a mold, a check valve provided at the starting end of the manifold, and a side passage between the mold and the check valve, and the plasticized plastic supplied through the manifold. The number of injection devices injected into the mold is the same as that of the mold, an on-off valve that is provided at a gate portion of the mold and opens only when the injection device communicates with the gate portion injects, and the injection device. The present invention provides an apparatus for manufacturing a hollow plastic body, characterized in that it is equipped with a control mechanism for sequentially performing injections of the apparatus.

Furthermore, in addition to the above-mentioned apparatus, the present invention also provides a means for extracting the plastic hollow body formed in the mold from the mold, a blowing device provided adjacent to the mold on the outside of the circumference, and The present invention provides an apparatus for producing a hollow plastic body, characterized in that it is equipped with means for charging the hollow plastic body into the blowing device.

The present invention will be described below with reference to the drawings which are examples.

Reference numeral 1 denotes an extrusion device, which heats and plasticizes raw material plastic supplied from a hopper 1a and continuously extrudes it from a nozzle 1b. A hot runner 2 is connected to the nozzle 1b and forms a flow path for the plasticized plastic extruded from the nozzle 1b. The hot runner 2 includes an introduction section 2a consisting of one flow path, a central chamber 2b connected to the outlet side of the introduction section 2a, and a plurality of manifolds 2c (eight in this embodiment) extending radially from the central chamber 2b.
It's getting more familiar. Each manifold 2c has the same length, and an injection mold 5 having a cavity mold 3 and a core mold 4 for molding a bottomed parison is disposed above the end portion thereof. That is, a plurality of injection molds 5 are arranged on a circumference centered on the center of the central chamber 2b. Further, a check valve 6 is provided at the starting end of the manifold 2c to prevent the plasticized plastics once fed into the manifold 2c from flowing back. Check valve 6 and gate portion 5a of injection mold 5
A side passage 2d communicates with the upper part of each manifold 2c between them, and each side passage 2d communicates with an accumulator 7. The accumulator 7 is a ram cylinder 7a
and ram 7b. The ram 7b is successively lowered by a drive mechanism (not shown) controlled by a control mechanism (for example a cam mechanism or a sequence circuit) not shown, from the central chamber 2b through the side passage 2d to the ram cylinder 7a. The plasticized plastic supplied therein is injected into an injection mold 5. That is, for example, as soon as the first ram reaches from top dead center to bottom dead center (the time in between is, for example, 20 seconds), the second ram, which had already risen to top dead center at that point, begins to descend. It is configured as follows. Injection mold gate part 5
A is provided with an on-off valve 8, which is normally closed and is controlled to open only when the ram 7b of the accumulator that shares the manifold 2c descends. Therefore, when no downward force is acting on the ram 7b, the plasticized plastic passes from the nozzle 1b of the extrusion device through the hot runner inlet 2a, the central chamber 2b, the inlet of the manifold 2c and the side channel 2d to the ram. 7b is supplied into the ram cylinder 7a until it reaches the top dead center. On the other hand, when the ram 7b descends, the check valve 6 closes and the on-off valve 8 opens, so that the plasticized plastic in the ram cylinder 7a passes through the gate 5a to the cavity mold 3 and core mold 4 of the injection mold. is injected into the void formed by the Note that the hot runner 2 and the accumulator 7 are provided with a heat retaining device, such as a band heater (not shown), and the plasticized plastic inside is kept at a predetermined temperature (usually about 3 to 5 degrees Celsius lower than the resin temperature in the extrusion device 1). ) is held.

The core mold 4 can be moved up and down by a hydraulic cylinder 9, and is timed so that when the core mold 4 is lowered and positioned within the cavity mold 3, injection is performed into the injection mold 5. . Numeral 11 is a pair of neck holders for holding the necks of the injection-molded bottomed parison 10, and a pair of these are fixedly installed at both ends of the horizontal rod 12. The center portion of the horizontal rod 12 is fixed to the lower end of a vertical shaft 13, and the vertical shaft 13 is configured to be movable up and down by a hydraulic cylinder 14 and rotatable by a rotating gear mechanism 15. . A temperature control device 16 is disposed at a symmetrical position of the injection mold 5 with respect to the axis of the vertical shaft 13 . The temperature control device 16 is used to adjust the temperature of the bottomed parison 10 to a predetermined temperature in preparation for the next step, stretch blow molding (which may also be simple blow molding). A stretch blow mold 17 is disposed adjacent to the temperature control device 16, and above the stretch blow mold 17 is an air cylinder 1 for vertically moving a stretch rod 18.
9 is provided. The bottomed parison 10 whose temperature has been controlled by the temperature control device 16 is placed in the net holder 1.
1 to the rotary lever 20, the rotary lever 20 moves the hollow body 21 to the stretch blow mold 17, and the stretch blow molded hollow body 21 is transferred to the rotary lever 20.
0, it is sent out of the stretch blow mold 17.

Using the above-described apparatus, a hollow body made of, for example, polyethylene terephthalate resin is manufactured in the following manner.

The resin pellets supplied from the hopper 1a are plasticized by the extrusion device 1, and are continuously sent to the hot runner 2a from the nozzle 1b at a constant flow rate. When the first ram 7b is currently in the descending process (for example, about 20 seconds), the core mold 4 of the first injection mold 7, which communicates with the first accumulator 7, is lowered and positioned in the cavity mold 3. . Therefore, the plasticized resin is injected into the gap formed by the cavity mold 3 and the core mold 4, and the bottomed injection parison 10 is formed. During this time, the on-off valve 8 of the communicating gate portion 5a is closed in the ram cylinder 7a containing the ram 7b that has descended in the previous process, so the plasticized resin flows through the hot runner 2, and the ram 7b rises. .
The other ram 7b is located at the top dead center. Then, the vertical shaft 13 and the core mold 4 are raised to release the parison 1.
0 is extracted from the injection mold 5, and then inserted into the core mold 4.
is separated from the parison 10. The other parison 10 held in the symmetrically located neck holder 11 and taken out from the temperature control device 16 at the same time is transferred to the stretch blowing mold 17 by the rotary lever 20. After that, the horizontal rod 12 rotates 180 degrees and descends,
The core mold 4 from which the parison 10 has been separated enters the injection mold 5 and waits for the next injection, while the core mold 4 holding the parison 10 enters the temperature control device 16 and enters the first ram 7b. The temperature of the parison 10 is controlled (for example, to 90° C.) until the next lowering of the temperature is completed. After the next lowering is completed, the parison 10 is pulled up from the temperature control device 16, and the drawing mold 1 is moved by the rotary lever 20.
7, and after stretch blow molding, the rotary lever 20 sends out the stretch blow mold 17 as a stretch blow hollow body 21.

Since the extrusion device used in the present invention only needs to have an extrusion flow capacity corresponding to approximately one injection mold, compared to the injection device of a conventional injection molding machine that molds the same number of molds per unit time, It has the advantage of being much smaller. Furthermore, since the residence time of the high-temperature plastic within the extrusion device is short, deterioration of the resin due to residence is prevented and a high-quality hollow body can be obtained. Furthermore, since the flow path distance from the extrusion device nozzle to each injection mold is the same, and the cooling conditions for each injection mold can also be made equal, the temperature conditions of the resin during molding in each injection mold are the same, and therefore residual strain etc. It has the advantage that a hollow body with uniform physical properties can be obtained. Furthermore, compared to conventional devices, it has the advantage that fewer neck holders or molds are required. In addition, the horizontal rod that transfers the parisons to the temperature control device only needs to hold and rotate two parisons at the same time, so it can be small and lightweight, speeding up the transfer, and controlling the temperature of the parisons during transfer. This has the advantage of preventing deterioration.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view of the device of the present invention, and FIG.
The figure is a plan view of the device of the invention. 1... Extrusion device, 1b... Nozzle, 2... Hot runner, 2c... Manifold, 2d... Side channel, 3... Cavity mold, 4... Core mold, 5...
Injection mold (mold), 5a...gate section, 6...check valve, 7...accumulator (injection device), 8...
...Opening/closing valve, 12...Horizontal rod (means for extracting the plastic hollow body), 13...Vertical shaft (means for extracting the plastic hollow body), 17...Stretching blowing mold (blowing device), 20...times dynamic lever (means of loading into the blowing device).

Claims (1)

[Scope of Claims] 1. An extrusion device for plasticized plastics, having a plurality of cavity molds and core molds disposed on the same circumference at the end side of a hot runner manifold connected to a nozzle of the extrusion device. A mold, a check valve provided on the starting end side of the manifold, and a side passage between the mold and the check valve to supply the plasticized plastic supplied through the manifold to the mold. The number of injection devices injected into the mold is the same as that of the mold, an on-off valve that is provided at the gate portion of the mold and opens only when the injection device communicates with the gate portion injects; 1. An apparatus for manufacturing a hollow plastic body, characterized in that it is equipped with a control mechanism for sequential operation. 2. An extrusion device for plasticized plastics, a mold having a plurality of cavity molds and a core mold disposed on the same circumference at the end side of a hot runner manifold connected to a nozzle of the extrusion device, and a mold of the manifold. a check valve provided on the starting end side; a mold provided in a side passage between the mold and the check valve for injecting the plasticized plastic supplied through the manifold into the mold; The number of injection devices equal to the number of molds, the on-off valve that is provided at the gate of the mold and opens only when the injection device communicates with the gate is injected, and the injection device for sequentially performing injections. A means comprising a control mechanism and for extracting the hollow plastic body formed by the mold from the mold, a blowing device provided adjacent to the mold on the outside of the circumference, and a means for extracting the hollow plastic body formed by the mold from the mold; 1. An apparatus for manufacturing hollow plastic bodies, characterized in that the apparatus comprises means for charging the hollow bodies into the blowing device.