JPH03176126A - Manufacture of multi-layer molded vessel - Google Patents

Abstract

PURPOSE:To obtain a thin multi-layer structural vessel, by a method wherein a multi-layer platelike preform is molded into disclike state with injection molding, which is arranged on a mold and molded with vacuum forming or air- pressure forming. CONSTITUTION:After injection of the first resin 41 within a nozzle 33 with a main injection molding unit, the second resin 42 is injected so that the second resin 42 is involved into the previously injected first resin 41. Then a three-layer structural resin molded body is molded by compressing the two kinds of resin 41, 42. Vacuum forming or air-pressure forming is performed by a method wherein a heated plug 48 is lowered calmly and air within a recessed part 46 is either sucked or air pressure is applied onto a preform 40 under a state where the fringe part is supported with a stepped part 47 of the perform 40 of the molded body so that a recessed part 46 of a mold 45 is filled in.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION 1 The present invention relates to a method for manufacturing a molded container with a multilayer structure, and particularly to a method for manufacturing a container suitable for use as a disposable simple container.

K Summary of the Invention: Before the first molten resin on the outside solidifies, a second resin is placed in the center of the first molten resin and encapsulated in the first resin, and then the indexed resin is compressed and flattened. The preform is molded into a disk-like shape, placed on a mold for vacuum forming or pressure forming, and heated and stretched by vacuum forming or pressure forming. It is designed to mold a multilayer container with a predetermined thickness.

K Conventional technology When molding disposable simple containers from synthetic resin moldings, a biaxial stretch blow molding machine is used to continuously mold cup-shaped products using a single resin raw material. I was doing it. In this case, the preform was first manufactured by index molding. Then press this preform into a plate shape! I was trying to do that.

Before the raw materials constituting the preform are completely cooled and solidified, the container is formed by vacuum forming or pressure forming while being pushed through a mold with a plug. The molded container is moved to the next process location and is then discharged and removed.

Problems to be solved by the K invention Σ According to the conventional molding method for such disposable resin containers, since a single resin raw material is molded, it may be difficult to mold other vacuum molded products or high-speed injection molded products. It has the drawbacks of slightly lower productivity and higher costs. Furthermore, since it is molded from a single resin, it is difficult to mold products with high burrs and properties, and it is difficult to mold products with a variety of other functions.

Another problem with molding is that a vertical injection molding machine must be used, and resin drips from the nozzle of this molding machine, which tends to clog the nozzle, or solidified resin adheres to the gate of the press plate. Therefore, there was a problem that the molding was not stable.

The present invention has been made in view of these problems, and it is an object of the present invention to provide a manufacturing method that allows a multilayer container to be freely formed using two or more types of resin. be.

Means for Solving Problem 1 The present invention involves molding a multilayer plate-shaped preform into a disk shape by injection molding, placing the disk-shaped preform on a mold, and using the mold to create a vacuum. A multilayer molded container is formed by molding or pressure molding.

K action) Therefore, the first resin is injected by the main injection molding unit, and the second resin is injected by the auxiliary injection molding units 1 to 1 connected to the joint block of the main injection unit so as to be enclosed in this resin. Inject the resin into the gate so that the second resin is encapsulated in the first resin, open the nozzle, and inject the first resin encapsulating the second resin into the injection space of the mold. At the same time, a preform is obtained by pressing the resin injected into the injection space of the mold with a screw. This preform is placed on a step formed at the top of the recess of a mold for vacuum forming or pressure forming, and is pressed by a heated plug while applying vacuum suction or air pressure. The preform is heated and stretched to obtain, for example, a cup-shaped disposable simple container.

K Embodiment FIG. 1 shows a molding apparatus for molding a multilayer container preform according to an embodiment of the present invention, and this molding apparatus is equipped with a main injection molding unit 10. A screw 12 for extruding molten resin is rotatably disposed within the cylinder 11 of the unit 10, and a joint block 13 is connected to the lower end of the cylinder 11. A resin passage 14 is formed vertically through the center of the joint block 13, and a torpedo 15 is disposed at a lower diameter portion of the resin passage 14. Further, the lower end side of the resin passage 14 constitutes a gate 16.

One auxiliary injection molding unit is connected to the joint block 13 of the main injection molding unit 10 so as to be orthogonal to the axis thereof. The auxiliary injection molding unit 19 comprises a cylinder 21 in which a piston 20 is slidably held. A plunger 23 is connected to the tip of the rod 22 of the piston 20. Further, a hopper 24 is provided at the upper part of the auxiliary injection molding unit 19, and the lower opening of this hopper 24 is connected to an oblique resin passage 25.
is communicated with. The terminal end side of the oblique resin passage 25 is communicated with a resin passage 26 passing through the center of the auxiliary injection molding unit 19. The plunger 23 faces this resin passage 26. A torpedo 27 is housed in the distal end portion of the resin passage 25, and
On the exit side of the torpedo 27, the resin passage 26 communicates with the center hole 28 of the torpedo 15 of the main injection molding unit 10.

Next, the structure of the preform molding die connected to the above-mentioned injection device will be explained, as shown in Fig. 2.
This mold includes an injection plate 31, and a recess 32 is formed in the center of the surface of the injection plate 31. An injection nozzle 33 is arranged so as to face the recess 32.

This nozzle 33 is connected to the gate 16 of the main injection molding unit 10. Further, an index paddle 34 is disposed in a ring shape below the injection plate 31 and on its outer periphery, and the pair of upper and lower carrier plates 35, 36 are held by this paddle 34. A compression piston 37 is disposed on the lower side of the ejection plate 31 so as to face the lower surface thereof. This compression piston 3
7 is fitted in a clamp ring 38 on the outer circumferential side (in a movable manner).

Next, a description will be given of a mold for molding a container using the preform 40 molded by the mold described above.
As shown in FIG. 7, a recess 46 corresponding to the shape of the container is formed in the mold 45.

A step 47 is formed at the shoulder portion of the opening of the recess 46 . Also, this mold 45 has a plug 48 that can be moved up and down.
is now set up.

In the above configuration, two types of resin are cut out from the preform using the injection molding apparatus shown in FIG. The main resin on the outside is extruded by rotating the screw 12 of the main index molding unit 10, and is extruded from the outer peripheral side of the torpedo 15 of the joint block 13 to the gate 16. On the other hand, the second resin is supplied into the hopper 24 of one auxiliary index molding unit. The resin in this hopper 24 is passed through a passage 25 through a passage 2 that penetrates the center of one unit.
Supply to 6. On the other hand, working fluid is supplied into the cylinder 21 to push the piston 20 to the right in FIG.
Press the second resin inside. Then, the pressed second resin is supplied from the resin passage 26 to the gate 16 through the center hole 28 of the torpedo 15 of the joint block 13.

In the case of such indexing of resin, as shown in FIG. (See FIG. 3), so that this second resin 42 is encapsulated in the first resin 41 that was injected earlier. Next, as shown in FIG. 3, the compression piston 37 in the crumbling ring 38 is raised, and the nozzle 33 is moved toward the center in the radial direction. As shown in FIG. It is aligned with the passage 39 formed in the center of the recess 32. Then, by applying pressure with the screw 12 of the main injection molding unit 10, the first resin 41 and the second resin 42 form a layer as shown in FIG. It will flow into the space between. During such an operation, the auxiliary index forming unit 1
The supply of the second resin 42 from 9 is stopped midway, and only the first resin 41 is indexed later.

In synchronization with the injection of resin for a predetermined period of time, the nozzle 33 is moved to the outer circumferential side in the radial direction, as shown in FIG. 5, to cut off the communication between its outlet portion and the two passages, and stop the supply of resin. .

Then, by raising the compression piston 37 in the clamp ring 38 and bringing it close to the lower surface of the injection plate 31, the two types of resins 41 and 42 are
is compressed to form a three-layer resin molded body. This molded body becomes a preform 40. The preform 40 is the sixth
As shown in the figure, the periphery of the index paddle 34 is gripped by the upper and lower carrier plates 35 and 36 held by the outer index paddle 34, and in this state, the compression piston 37 is lowered and , lower the index paddle 34.

This causes the preform 40 to separate from the injection plate 31 of the mold. Therefore, in this state, the preform can be taken out from the mold.

The preform 40 thus obtained is supported at its peripheral edge by a step 47 so as to close the recess 46 of the mold 45 shown in FIG.

In such a state, the heated plug 48 is gently lowered and the air inside the recess 46 is sucked, or
By applying air pressure to the preform 40 from above, vacuum forming or pressure forming is performed.
As a result, a cup-shaped simple container 5 as shown in FIG.
1 will be molded.

In this way, this embodiment focuses on multi-layering the preform 40, and assembles one plunge set type auxiliary injection molding unit into the inner screw type main index molding unit 10 as shown in FIG. A combined multi-layer injection molding machine is used. Further, in the mold for molding the preform 41, as shown in FIGS. 5 and 6, the outer edge of the multilayer disc-shaped molded body constituting the preform 40 is V-bonded with a carrier plate 35, 36, It is formed into a shape that allows metal to be tightened or wrapped around the outer periphery. The disk portion other than the FM@ portion of the carrier plate 35, 36 is formed by vacuum or pressure forming as shown in FIG.

As the combination of the first resin and the second resin, various combinations as shown below are possible.

Further, the mixing ratio (weight ratio) of the second resin is preferably within the range of 10 to 50%. In addition, when mixing AD resin with polypropylene resin (PP) to constitute the first resin, AD
It is preferable that the resin content be within the range of 10 to 50%.

First resin Second resin PCMXD-6NY PCEVO day PET MXD-6NYPET
EVO NYPP+AD-Resin MXD-6NYPP+A
D-L/JIN EVOHHI PS+AD-Resin MXD-6NY IPS+AD-Resin
EVO port Also, a third resin 43 consisting of an adhesive layer is interposed between the first resin 41 and the second resin 42 as shown in FIG. It may also be used as an adhesive layer with the resin 42 of No. 2. @3
As the resin 43, it is possible to use an adhesive resin such as Atmer (Mitsui Petrochemical) or Modelc (Mitsubishi Yuka), and by using such a third resin 43, the first It becomes possible to increase the adhesive force between the resin 41 and the second resin 42 to zero.

As shown in FIG. 8 or FIG. 9, the container 51 manufactured by the method of this embodiment is a plastic container with a multilayer structure, such as a container with a sloped shape such as an index molded product, or a container with a thick wall. It can be applied not only to containers but also to containers of various shapes. Moreover, the shape can be selected relatively freely, and it becomes possible to mold a thin-walled container. In addition, the flange portion 52 of the container 51 can be freely formed, and the dimensional stability of the flange 52 due to vacuum forming improves the fit with the lid, making it possible to tighten not only the sealing material but also the metal. It becomes possible. Furthermore, by making the container multi-layered, it becomes possible to create a container with oxygen barrier properties.

K Effect of the invention 2 As described above, the present invention molds a multilayer plate-shaped preform into a disk shape by injection molding, places this disk-shaped preform on a mold, and performs vacuum forming or The container is formed between strips by air pressure forming.

Therefore, by vacuum forming or pressure forming, it is possible to select the shape relatively freely and form a container with a thin multilayer structure. Furthermore, by selecting the type of resin with a multilayer structure, it is possible to impart gas barrier properties, particularly Fi element barrier properties, to the container.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an injection device for indexing a preform according to an embodiment of the present invention, and FIGS. 2 to 6 are molds showing step-by-step operations for molding this preform. , FIG. 7 is a longitudinal sectional view of a mold for vacuum forming or pressure forming, FIG. 8 is a longitudinal sectional view of a molded container, and FIG. 9 is a partially enlarged sectional view of a container with a modified structure. It is a diagram. The names of the main parts in the drawings are as follows. 10.. 19.. 31.. 33.. 35.. 36.. 37.. 40.. 41.. 42.. 45.. 46.. 47.. ・Main injection molding unit・Auxiliary injection molding unit・Injection plate, injection nozzle, carrier plate (top), carrier plate (bottom), compression piston, preform, first resin, second resin, mold, recess, step 8, plug

Claims (1)

[Claims] 1. A multilayer plate-shaped preform is molded into a disk shape by injection molding, the disk-shaped preform is placed on a mold, and a multilayer molded container is formed by vacuum forming or pressure forming using the mold. A method for manufacturing a multilayer molded container, characterized in that the container is molded.