JP3249054B2 - Method and apparatus for manufacturing multilayer container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a multilayer container , and more particularly to a method and an apparatus suitable for manufacturing a multilayer container having a peeling function.

[0002]

2. Description of the Related Art Conventionally, a multi-layer container is a multi-layer die head of a hollow molding machine, in which a molten resin supplied from a plurality of extruders is formed into a layer, and the respective layers are merged in a discharge nozzle of the die head to form an integrated parison of each layer. The parison is discharged between the molds to be molded.

[0003] In recent years, multilayer containers having a peeling function have been used for large containers for shampoos and rinses. That is, when the contents are discharged by the pouring pump attached to the mouth of the container, the inside of the container may be under negative pressure and the external shape of the container may be deformed, or it may be difficult to discharge the contents. In order to prevent this, for example, Japanese Patent Application Laid-Open No. 5-213
No. 372 proposes a multilayer container as shown in FIG. 6 and a method for manufacturing the same. That is, the multilayer container 27
The main body 28 has a two-layer structure including an outer layer portion 30 and an inner layer portion 29, and the outer layer portion 30 and the inner layer portion 29 are made of different resins having no adhesive property to each other. Further, the thickness of the inner layer portion 29 is formed smaller than the thickness of the outer layer portion 30. At the bottom portion 31 of the main body 28, a vent hole 32 is formed between the outer layer portion 30 and the inner layer portion 29 to allow air to flow in when the contents are discharged, and the degree of vacuum generated by discharging the contents is equal to the atmospheric pressure. And

[0004] The container 27 manufactured in this manner has a monolithic structure immediately after molding because it is formed by multi-layer molding using non-adhesive resins, but the pouring pump attached to the mouth 33 of the container 27. Each time the contents are discharged by 34, the inner layer part 29 gradually contracts while leaving the outer layer part 30, and the contents can be efficiently discharged to the end.

[0005] The purpose of the vent hole 32 is to prevent a vacuum state generated when the inner layer portion 29 is crushed due to the decrease of the contents in the multilayer container 27 having a peeling function. After the molding, the inner layer portion 29 was once peeled off, and the vent hole 32 was formed in the outer layer portion 30.

[0006]

The conventional multi-layer container and the method for manufacturing the same have the following problems because they are configured as described above. (A) Since the pinch-off portion of the molded multilayer container has a multilayer structure and has a peeling function, the strength at the pinch-off portion is reduced. (b) The pinch-off burrs are also multilayered, making it difficult to reuse. (c) It is difficult to adjust the thickness of each layer due to the difference in the flow of each layer in the multilayer die head. In particular, in the case of a multi-layer container having an inner layer peeling function, the inner layer portion is usually thinner than the outer layer portion, so that when the parison is discharged, the wall thickness in the circumferential direction tends to vary due to the influence of the outer layer portion. Further, since there is no uneven thickness adjustment function, the variation cannot be eliminated. (d) In the case of a multi-layer container having an inner layer peeling function, it is desirable that the inner layer portion be crushed small in order to improve the discharge property of the contents, but usually, as shown in FIG. Since B is wide, it is hard to be crushed by being pressed by the inner and outer layer pinch-off portions B as the contents are discharged. Also,
The thickness around the pinch-off portion is small because the blow ratio is small, and it is harder to collapse. Therefore, the discharge property of the contents is deteriorated. (e) In the case of a multilayer container having an inner layer peeling function, it takes time and labor to process the ventilation holes in the multilayer portion, and at that time, the container body may be crushed or deformed. In addition, the occurrence of peeling of the pinch-off portion and the removal of dust powder generated at the time of drilling have also been problems.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem of the prior art, and has a high strength of a pinch-off portion, and is capable of reusing burrs.
It is another object of the present invention to provide a method and apparatus for manufacturing a multilayer container suitable for manufacturing a multilayer container having an inner layer peeling function, and a multilayer container.

[0008]

According to the present invention, the above-mentioned problems have been solved as follows. That is, the preform is transferred directly below the die head, the parison is discharged from the die head to cover the preform, the parison is vacuum-molded in a molding die to form an outer layer, and the preform is blow-molded to form an inner layer. To produce a multilayer container comprising inner and outer layers.

In the molding of the multi-layer container, the pinch-off portion is formed only of the resin for the outer layer, so that the strength of the multi-layer container can be increased and the burr of the pinch-off portion can be regenerated.

Further, by forming the outer layer parison and the preform from different resins having no adhesiveness to each other, a multilayer container having a peeling property can be easily obtained, and by changing the material of the preform, the inner layer can be formed. The material can be changed easily. Since the preform is used for the inner layer as described above, multilayer molding can be performed even with a single-layer manufacturing apparatus.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The multilayer container according to the present invention is characterized in that an outer layer formed by a parison and an inner layer formed by a preform are in close contact with each other.

The method for producing a multilayer container according to the present invention is characterized in that a preform is transferred directly below a die head, a parison is discharged from the die head to cover the preform, and molded in a molding die. More specifically, the parison is characterized in that the parison is vacuum-molded into an outer layer portion, and the preform is blow-molded into an inner layer portion.

An apparatus for manufacturing a multilayer container according to the present invention comprises a die head for discharging a parison as an outer layer, a preform transfer device for transferring a preform as an inner layer immediately below a die head, a molding die, and a lower air. And a blowing device.

It is preferable that the preform transfer device comprises a preform box for heating the preform, and a drive unit for transferring the preform box immediately below the die head.

It is preferable that the molding die is a vacuum molding die that sucks air in the die from an outer peripheral wall of the die. In the case of producing a multilayer container having a peeling function, it is preferable that the molding die is provided with a hole forming means for forming a vent in an outer layer portion.

[0016]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an apparatus for manufacturing a multilayer container according to the present invention. FIG. 1 (a) shows a die head, a molding die and a lower air blowing device, and FIG. 1 (b) transfers a preform immediately below a die head. It is a figure which shows a preform transfer apparatus.

In FIG. 1A, the reference numeral 1 denotes a die head having a substantially cylindrical shape as a whole, and a head core 3 is inserted into a head main body 2 of the die head 1.

A cylindrical resin flow path 4 is provided between the head body 2 and the head core 3.
Is connected via a manifold 6 to an extruder 5 connected to the upper part of the outer peripheral wall of the head body 3.

At the lower part of the head body 2, a die outer cylinder 7,
A die inner cylinder 8 is attached to a lower portion of the head core 3, and a discharge nozzle 9 is formed by an annular gap between the die outer cylinder 7 and the die inner cylinder 8.

The gap between the discharge nozzles 9 can be freely adjusted by moving the die outer cylinder 7 to the left and right in the figure, and the thickness of the parison 10 discharged from the discharge nozzles 9 in the circumferential direction can be adjusted. it can.

That is, the molten resin intermittently or continuously extruded by the extruder 5 is supplied into the resin flow path 4 through the manifold 6 of the die head 1 to become cylindrical, and the thickness is adjusted by the discharge nozzle 9. Then, it is discharged as a parison 10.

Below the die head 1, a parison 10
Is provided with a molding die 11 for performing vacuum molding by sucking air in the die from an outer peripheral wall thereof, and a lower air blowing device 12 for blowing air into a preform described later.

FIG. 1B shows a preform transfer device 14 for transferring a preform 13 formed by an injection machine directly below the die head 1. The transfer device 14 is a preform box 15 for heating the preform 13. And a drive unit 16 for transferring the preform box 15 directly below the die 1.

FIG. 2 is a process diagram showing the preform molding and its reheating. Usually, the preform 13
As shown in FIG. 2A, an injection mold 2 including a cavity mold 21, a neck mold 22, and a core mold 23.
In FIG. 2, the molten resin is injected by an injection machine, pulled out from the cavity mold 21 as shown in FIG. 2 (b), and molded as a test tube with a bottomed parison. There are hot parison method and cold parison method for forming a hollow molded article from this preform. In the hot parison method, the molded preform is transferred to a temperature adjustment step without completely cooling, and blow molding is performed. The cold parison method is a method in which a molded preform is cooled once, and then reheated to perform blow molding.

In the present invention, it is desirable to apply the cold parison method. Usually, a heating mold 1 as shown in FIG.
4 are used. This heating mold can be used as the preform box 14.

Next, a process of manufacturing a multilayer container by the above-described manufacturing apparatus will be described with reference to FIGS.
FIG. 3 is an explanatory diagram showing a manufacturing process of the multilayer container, and FIG. 4 is a flowchart for explaining the manufacturing process shown in FIG.

As shown in FIG. 3A, the heating of the preform 13 is started by the start of the automatic operation, and the molding die 11 (not shown) is advanced immediately below the die head 1 (step 1).

Next, as shown in FIG. 3 (b), the preform box 15 is advanced directly below the die head 1 by the drive unit 16 (step 2), and the blowing nozzle 25 of the lower air blowing device 12 is raised one step. , Preform box 1
A set pin is driven into the preform 13 in 5 (step 3).

Next, as shown in FIG. 3C, the preform box 15 is opened and the box 15 is retracted (step 4).
0 is discharged (step 5).

Next, as shown in FIG. 3 (d), to confirm the parison length (Step 6), the molding die 11 and the mold clamping, pinching the top and bottom of the parison 10 (step 7).

When the upper part of the parison 10 is pinched, by pinching together with a part of the upper part of the preform 13, the bottom part of the preform 13 can be fixed.

Subsequently, after the parison 10 is vacuum-molded by sucking air in the mold from the outer peripheral wall of the molding mold 11, air is blown from the blowing nozzle 25 to blow-mold the preform 13 (step 8). ).

Next, the blowing nozzle 25 is raised two steps (step 9), and the opening of the container is formed.
Is transferred (step 10), the air blown into the preform is exhausted (step 11), the molding die 11 is opened, and the molded multilayer container is taken out of the molding die 11 (step 12). Next, returning to step 1, the next molding is performed in the same steps.

FIG. 5 shows a multilayer container manufactured by the above-described manufacturing process. FIG. 5A is a longitudinal sectional view, and FIG. 5B is a bottom view.

As shown in FIG. 5 (b), the multilayer container 27 according to the present invention has no inner pinch-off portion and only the outer layer pinch-off portion A.
In this case, the inner layer portion 29 of the main body 28 is easily crushed, and the discharge property of the contents is improved.

In the case of a multilayer container 27 having a peeling function, the outer layer 30 and the inner layer 29
The multi-layer parison according to the present invention is not a parison integrated with each layer but a separate parison, and a method for forming the outer layer parison 10 and the preform 13 is required. Is changing
When the outer parison 10 is formed, a pin or the like is protruded from the mold cavity in advance, and then the outer parison 10 is formed and drilled. 31 can be processed.

The vent hole 31 can be opened at any position, and can be formed simultaneously with the molding of the outer parison 10, so that the process is shortened and the container is not deformed, so that defective products are not generated. Absent. Further, the removal of dust powder after processing becomes unnecessary.

In the above-described embodiment, the manufacture of the two-layer container composed of the preform and the outer parison has been described.
It becomes possible to manufacture a multilayer container having more than two layers.

In the above embodiment, the production of a multilayer container having a peeling function has been mainly described. However, an ordinary multilayer container can be produced by forming an adhesive layer on the inner wall of the outer parison or the outer wall of the preform. .

[0040]

Since the present invention is configured as described above, the following effects can be obtained. (a) Since the pinch-off portion of the molded multi-layer container has only the outer layer, the strength of the pinch-off portion can be increased and the burr of the pinch-off portion can be regenerated. (b) The formation of each parison is not affected by other layers. (c) The material of the inner layer portion can be selected from various types by changing the material of the preform. The thickness of the inner layer can be freely changed by changing the thickness of the preform. (d) Since a preform is used for the inner layer, multilayer molding can be performed even with a single-layer manufacturing apparatus. Further, the moldability of the mouth of the container is remarkably improved, and the sealing property of the mouth is also improved. (e) Since the inner layer portion of the multilayer container having a peeling function is fixed at a part of the mouth and the bottom when the contents are discharged, the crushing rate is high and the dischargeability is high. (f) Even if the inner layer of the multilayer container is peeled off and a gap is formed between the outer layer and the inner layer, the inner layer is not danced because it is fixed at a part of the mouth and the bottom. (g) Vent holes can be easily formed in the outer layer portion of the multilayer container having a peeling and separating function.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing an apparatus for manufacturing a multilayer container according to the present invention. FIG. 1 (a) shows a die head, a molding die and a lower air blowing apparatus, and FIG. 1 (b) transfers a preform immediately below a die head. FIG. 2 is a view showing a preform transfer device to be used.

FIG. 2 is a schematic process drawing showing the molding of a preform and its reheating.

FIG. 3 is a process chart showing a manufacturing process of a multilayer container according to the present invention.

FIG. 4 is a flowchart for explaining a manufacturing process shown in FIG. 3;

5A and 5B are diagrams showing a multilayer container manufactured by the manufacturing process according to the present invention, wherein FIG. 5A is a longitudinal sectional view and FIG. 5B is a bottom view.

6 is a view showing a conventional multilayer container, FIG. 6 (a) is a longitudinal sectional view, and FIG. 6 (b) is a bottom view.

[Explanation of symbols]

 Reference Signs List 1 die head 10 parison (outer parison) 11 molding die 12 lower air blowing device 13 preform 14 preform transfer device 15 preform box (heating die) 16 drive unit 27 multilayer container (container) 28 main body 29 inner layer 30 outer layer Part 31 Bottom 32 Vent

Claims (6)

(57) [Claims] 1. A preform (10) is transferred to a position immediately below a die head (1), and a parison (10) is discharged from the die head (1) to cover the preform (13). A method for producing a multilayer container, comprising: 2. The parison (10) is vacuum-molded in a molding die (1) to form an outer layer (30), and the preform (13) is blow-molded to form an inner layer (29). The method for producing a multilayer container according to claim 1 . 3. A parison (10) to be a multilayer part (30).
Head (1) that discharges a preform, a preform transfer device (14) that transfers a preform (13) to be an inner layer portion (29) immediately below the die head (1), and a molding die (1).
1) and a lower air blowing device (12). 4. The preform transfer device (14),
A preform box (15) for heating the preform (13), and a drive unit (16) for transferring the preform box (15) directly below the die head (1). Item 4. An apparatus for producing a multilayer container according to Item 3 . 5. The multi-layer container according to claim 3, wherein the molding die is a vacuum molding die for sucking air in the die from an outer peripheral wall of the die. apparatus. 6. An outer layer part (3) is provided in said molding die (11).
6. The apparatus for producing a multilayer container according to claim 3, further comprising a hole making means for forming a ventilation hole in the hole.