JP2000158521A - Double container molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the trouble due to the leakage of content caused by the damage to an inner layer parison by surely forming a venting hole and eliminating necessity projecting an air venting pin toward the inner layer parison to a necessary degree or more. SOLUTION: When a double container of which the inner and outer layers are peeled is molded, at least one air venting pin 50 is almost vertically arranged at the lower position of the inner layer parison 16 having a pinch part formed thereto and, when the inner layer parison 16 and an outer layer parison 15 having necessary length are extruded from a hollow molding machine 1, the air venting pin 50 is inserted in the opening part of the outer layer parison 15 and, in this state, a mold 24 is closed and the opening part is pinched along with the air venting pin 50 by the lower parts of the mold register surfaces of the mold 24 to form a pinch part in the vicinity of the air venting pin 50 and, thereafter, the air venting pin 50 is pulled out to form the air vent hole of an outer layer part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for forming a double container.

[0002]

2. Description of the Related Art Conventionally, there has been known a double container having an inner layer portion and an outer layer portion made of a synthetic resin and separating the inner and outer layers. This type of double container is used to store liquids such as shampoo, rinse, cosmetics, etc., and the outer layer is deformed by discharging the contents by the extraction pump attached to the mouth of the container. However, only the inner layer portion gradually contracts and deforms according to the consumption of the contents.

[0003] The double container 31 will be described with reference to FIG. The double container 31 generally has an opening 37 to which a lid 36 and an extraction pump 38 are attached, and a container main body 32, and the container main body 32 is constituted by an inner layer portion 34 and an outer layer portion 33 having peelability. Have been. The inner layer portion 34 and the outer layer portion 33 are formed of a synthetic resin having low adhesion to each other. Usually, the outer layer portion 33 is formed to be thicker than the inner layer portion 34 to impart mechanical properties to the outer layer portion 33. , Giving the inner layer portion 34 a property of being easily deformed. In order to facilitate deformation of the inner layer 34, a vent hole 39 'indicated by a virtual line is formed at an arbitrary position on the bottom 35 of the outer layer 33. Mouth 3
7 is formed by integrating the inner parison and the outer parison. However, in the conventional double container 31, the central vent hole 39 is not formed.

In such a double container 31, an inner parison and an outer parison are extruded by a multilayer die head of a hollow molding machine, and the lower end of the inner parison and the lower end of the outer parison are pinched by a pinch portion. Then, the inner parison and the outer parison having a predetermined length are individually expanded and formed.

Conventionally, the vent hole 39 'is formed by piercing the outer parison when the outer parison is expanded. That is, a through hole is formed in at least one bottom of the pair of molds, the inner parison and the outer parison are received in the mold, the mold is closed, and a pin is inserted from the through hole into the cavity. The outer parison, which protrudes and expands due to vacuum formation in the closed state of the mold, is pressed against the pin, and a vent hole 39 'is formed by penetrating the pin.

[0006] However, such a conventional method for forming a double container has the following technical problems. That is, since the vent hole 39 is formed by piercing the outer layer parison, when using a kind of synthetic resin that is easily elastically deformed, the outer layer parison extends and the vent hole 39 may not be formed. . On the other hand, when the pin is protruded into the mold long so that the air hole 39 is formed even when the outer parison extends, the inner parison is damaged by the pin, and in a remarkable case, the inner parison is broken. Leakage of the liquid contained in the double container.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional technical problems, and has the following configuration. According to the first aspect of the present invention, the opening at the lower end of the inner parison 16 is sandwiched by the pinch portions 16b while being pushed out of the blow molding machine 1, and the opening 15a at the lower end of the outer layer parison 15 is pinched at the pinch portion 15b. The outer layer parison 15 is expanded in the mold 24 to form the outer layer 33 having the vent hole 39, and the inner layer parison 16 is expanded in the mold 24 to form the inner layer 34. Double container 3 with separation between 34 and 33
In the method for molding a double container for molding
At least one air release pin 50 is disposed substantially vertically below the inner layer parison 16 where the 6b is formed,
When the inner parison 16 and the outer parison 15 having the length necessary to form the double container 31 are extruded from the blow molding machine 1, the air release pin 50 is received in the opening 15 a of the outer parison 15. The mold 24 is closed with the mold, and the opening 1 is closed by the lower part of the mold mating surface of the mold 24.
5a is pinched together with the air release pin 50 to form the pinch portion 15b at a position other than the air release pin 50, and then the air release pin 50 is removed to form the ventilation hole 39 of the outer layer portion 33. This is a method for forming a double container. The invention according to claim 2 is the mold 2
The method according to claim 1, wherein a concave portion (24b) for receiving the air release pin (50) is formed on the mold matching surface (4). The invention according to claim 3 is characterized in that the pinch portion 16 is sandwiched between the openings of the inner parison 16.
3. The method for forming a double container according to claim 1, wherein the air vent pin 50 is disposed at a position below the pinch portion 16b of the inner layer parison 16 after being closed by b. The invention according to claim 4 is characterized in that the air release pin 50
4. The method for forming a double container according to claim 1, wherein the inner container is removed before the inner layer is formed by expanding the inner layer parison.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 show one embodiment of the present invention.
An embodiment will be described. In FIG. 3, reference numeral 1 denotes a multi-layer die head of a blow molding machine, and an outer layer nozzle 13 having an annular shape.
Are connected to an outer layer extruder 6 via a cylindrical outer layer channel 5 and a manifold 7. The outer layer channel 5 is partitioned between the head body 2 and the die outer cylinder 11 and the cylindrical member 3. The outer layer extruder 6 includes a cylinder device 6a (storage and supply device) that can measure, store, and discharge the molten material in a molten state, so that intermittent supply of the molten material is possible.
An annular inner layer nozzle 14 located on the inner diameter side of the outer layer nozzle 13 of the multilayer die head 1 is connected to the inner layer extruder 9 via a cylindrical inner layer flow path 8 and a manifold 10. . The inner layer extruder 9 is capable of continuously supplying a molten material.

Reference numeral 19 denotes an air flow path, which is a multilayer die head 1
The center of the die 12 is fixed to the lower end of the head core 4 through the head core 4 that defines the inner wall of the inner layer flow path 8 at the center of the die.

Then, the air release pin 50 shown in FIG.
Are arranged at least below the multilayer die head 1. The air bleeding pin 50 has a driving device 51 attached thereto, and the air bleeding pin 50 arranged substantially vertically is driven up and down by the driving device 51. In the illustrated example, the driving device 51 is fixed to the movable member 52, and the movable member 52 is moved in the left-right direction in the drawing, so that the air release pin 50 is attached to the multilayer die head 1 shown in FIG. It is possible to move between the lower position and the lower position of the air blowing device 25 shown in FIG. This air release pin 5
The driving device 51 and the movable member 52 constitute an air vent pin device 59. The actual air release pin device 59 moves together with the mold 24.

The driving device 51 is constituted by a double-acting cylinder device, and includes a cylinder 53 fixed to a movable member 52.
The piston 54 is slidably fitted to the first pressure chamber 55a.
The second pressure chamber 55b is partitioned, and an air vent pin 50 is attached to the upper end of the piston rod 56. Thus, a working fluid such as pressurized air is supplied to the first pressure chamber 55a, and the working fluid in the second pressure chamber 55b is discharged, so that the piston 54, the piston rod 56 and the air release pin 50 are driven upward, and The working fluid is supplied to the second pressure chamber 55b, the working fluid in the first pressure chamber 55a is discharged, and the piston 54, the piston rod 56 and the air release pin 50
Is driven downward.

The air release pin 50 is sandwiched by the bottom of the mold mating surface of the mold 24 and penetrates the outer layer parison 15.
Has a function of forming a vent hole 39 at the lower end of the. For this reason, as shown in FIG. 2, a concave portion 24b is formed substantially at the center of the bottom of the mold matching surface of the mold 24, and the concave portion 24b is formed.
The air release pin 50 is received. The mold 2
4 is constituted by a pair of split molds 24A and 24B,
The concave portion 24b is formed so as to face the split molds 24A and 24B. In the mold matching state, the air release pin 50 is received in the loosely inserted state, and a part of the outer layer parison 15 is sandwiched around the air release pin 50. I'm sorry. But,
In the mold matching state, the air release pin 50 can be tightly received in the concave portion 24b, and the post-processing work for removing the outer layer parison 15 remaining in a concave shape in the concave portion 24b can be made unnecessary.

Next, a method of forming a double container using the above-described hollow forming machine will be described. When the inner layer extruder 9 is driven, the molten material from the inner layer extruder 9 flows through the manifold 10 and the inner layer flow path 8 and is continuously extruded from the inner layer nozzle 14 in the form of a cylinder to form an inner layer parison. 16 begins to form. After the discharge of the inner parison 16 is started, a small amount of the support air is continuously supplied into the inner parison 16 from the air flow path 19 to keep the inner parison 16 cylindrical, and the pinch device 21 is moved to a predetermined position. It is driven upward toward the position. At this time, the air release pin device 59
Takes a position that does not interfere with the pinch device 21.

When the inner parison 16 has been suspended for a predetermined length, this is detected by a position detector (not shown) and, as shown in FIG. 4 (a), the pinch portion 22 of the pinch device 21 at a predetermined position. Is driven, the lower end of the inner parison 16 is pinched and closed as a pinch portion 16b.

After the pinch drive of the pinch device 21,
As shown in FIG. 4B, after the pinch device 21 is driven down, a passage such as the air release pin device 59 is formed, and the mold 24 and the air release pin device 5 are opened.
9 move downward of the multilayer die head 1.
A pinch portion 16b sandwiching the opening of the inner parison 16
After being closed by the air vent pin 50, the air vent pin 50 is disposed below the pinch portion 16b of the inner layer parison 16, thereby forming the pinch portion 16b of the inner layer parison 16 and the vent hole to be described later by the air vent pin 50. The operation of forming the outer layer parison 15 into the outer layer parison 15 can be performed smoothly. Although the mold 24 is open right and left in FIG. 4C, the mold 24 is actually open front and back in FIG. 4C.

On the other hand, the pinch portion 16b of the inner layer parison 16
In the multilayer die head 1 before and after the formation of the molten material, the molten material previously stored in the cylinder device 6a of the outer layer extruder 6 is extruded and passed through the manifold 7, the outer layer flow path 5, and the outer layer nozzle 13. Depending on the molten material discharged
The outer parison 15 begins to form. Outer Parison 15
Is formed intermittently and in a short time (2 to 3 seconds) by the operation of the cylinder device 6a. FIG. 4C shows a state in which the outer layer parison 15 is substantially formed and finished.
As a result, the outer layer parison 15 and the inner layer parison 16 are received between the molds 24 in the opened state, and the air release pin 5 is located below the opening 15 a at the lower end of the outer layer parison 15.
0 is facing down.

If the molten material in the cylinder device 6a is extruded by a predetermined amount and the outer parison 15 is formed with a predetermined length, the lower end of the outer parison 15 reaches a position slightly lower than the pinch portion 16b of the inner parison 16. This is detected and confirmed by a position detector (not shown). Further, as shown in FIG. 5, the air release pin 50 is driven to rise. The air release pin 50 is driven to rise by the driving device 51 and is positioned so as to be sandwiched between the lower ends of the mold 24 in the open state.

Then, when the inner parison 16 and the outer parison 15 having the lengths necessary to form the double container 31 are extruded from the multilayer die head 1, as shown in FIG. 4 (d) and FIG. 24 is clamped by a mold clamping device (not shown), and the opening 15a at the tip of the outer parison 15 is
4A and 24B are pinched by the lower portions of the mold mating surfaces, and the vicinity of both sides of the air release pin 50, that is, portions other than the location of the air release pin 50 in the opening 15a are closed by the pinch portion 15b, The upper portions 17 of the molds 15 and 16 are annularly fastened by the upper end openings 24a of the mold matching surfaces of the mold 24. At this time, the air release pin 50 is received in the recess 24b. The pinch portion 15b of the outer layer parison 15 is formed at the bottom 35 of the double container 31 shown in FIG. 7 according to the outer diameter of the outer layer parison 15, and a vent hole 39 is formed at the center. By receiving the air release pin 50 in the recess 24b, it is possible to form the large vent hole 39 while firmly sandwiching the pinch portion 15b.

The upper end opening 24a of the mold mating surface of the mold 24
As a result, the inner parison 16 is independently tightened by the upper end opening 24a of the mold 24, and the outer parison 15 is also independently tightened with a part thereof cut off. Can be

Almost simultaneously with the closing of the mold 24, a large amount of air is supplied from the air passage 19 into the inner parison 16 in a short time. As a result, as shown in FIG. 1, a relatively soft portion at the upper end of the inner parison 16 (above the upper portion 17 fastened by the upper end opening 24a of the mold 24) swells, and the inner parison 16 becomes large. An aperture 16c is formed. The large-diameter portion 16c is used for the multilayer die head 1
This is where the inner parison 16 and the outer parison 15 are cut and separated, and also where the blow nozzle 26 to be described later is driven.

Next, a mold 24 holding the inner parison 16 and the outer parison 15 cut to a predetermined length is provided.
Is moved below the air blowing device 25 as shown in FIG. At this time, the air in the mold 24 is sucked to vacuum-mold the outer layer parison 15 into the outer layer portion 33 having a predetermined shape. Vacuum forming is performed by using an inner wall (cavity) of the mold 24 and the outer parison 1
5 can be formed by suctioning a vacuum pump (not shown). The mold clamping device moves between the multilayer die head 1 and the air blowing device 25 together with the mold 24 and the air release pin device 59.

Next, the blow molding of the inner parison 16 is performed by the air blower 25. Before starting the blow molding of the inner parison 16, the air release pin 50 is removed from the outer parison 15 and the mold 24. Remove it. The removal of the air release pin 50 is performed by lowering the air release pin 50 by the driving device 51. This prevents the inflating inner parison 16 from being pierced by the air release pin 50.

In the air blowing device 25, as shown in FIG.
Hold down. Further, a blow nozzle 26 is driven into the large diameter portion 16c which is cut and gradually increases in diameter upward, so that the upper end portions of the inner parison 16 and the outer parison 15 are cut off, and the inner parison 16 is blow molded. During the blow molding of the inner parison 16, the air between the inner parison 15 and the outer parison 15 flows out of the vent hole 39 to the outside.

Thus, when the outer layer 33 of the double container 31 is formed by the outer layer parison 15 and the inner layer 34 of the double container 31 is formed by the inner layer parison 16 and sufficiently cooled, a mold is formed. The mold 24 is opened and the molded double container 31 is taken out. By repeating the above operation, the double containers 31 are formed one after another.

The double container 31 has a mouth 37 as described above.
A lid 36 and an extraction pump 38 are attached to the device for use. As the contents are consumed, air from the vent holes 39 flows into the outer layer portion 33.

In the above embodiment, the inner layer parison 16 is formed from the molten material continuously supplied from the inner layer extruder 9, and the molten material supplied intermittently from the cylinder device 6a. Although the outer layer parison 15 is formed by using the molten material supplied intermittently, both the inner and outer layer parisons 16 and 15 can be formed by the intermittently supplied molten material. It is theoretically possible to form. In addition, one air vent pin 50 was used, and one vent hole 39 was formed in the center of the bottom 35 of the outer layer portion 33 of the double container 31, but a plurality of air vent pins 50 were used. A plurality of ventilation holes 3 in the bottom 35
9 can also be formed.

Further, in the above embodiment, before starting the blow molding of the inner layer parison 16,
Was removed from the outer layer parison 15 and the mold 24, but it is sufficient that the inner layer parison 16 can be prevented from interfering with the air release pin 50. Accordingly, the air vent pin 50 is hollowed to form an air passage, and the blow molding of the inner parison 16 is started while the air in the outer layer portion 33 after the vacuum molding is discharged from the air passage of the air vent pin 50. Then, the air release pin 50 can be removed just before the end of the blow molding of the inner layer parison 16.

[0028]

As will be understood from the above description,
According to the method for forming a double container according to the present invention, the following effects can be obtained. According to the first aspect of the present invention, when the pinch portion is formed by sandwiching the opening at the lower end of the outer layer parison with the lower part of the mold mating surface of the mold, the air release pin enters the opening of the outer layer parison. In this state, an air vent pin is received between the mold mating surfaces of the mold, and then the air vent pin is withdrawn to form a vent hole in the outer layer portion. As a result, not only is the vent hole reliably formed, but also the air vent pin does not need to protrude toward the inner parison more than necessary, eliminating problems caused by leakage of contents caused by damage to the inner parison. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a hollow molding machine used in a method for molding a double container according to an embodiment of the present invention.

FIG. 2 is a bottom view showing the same mold.

FIG. 3 is a sectional view showing the same multilayer die head.

FIG. 4 is an explanatory view showing a cross section of a manufacturing process of the double container.

FIG. 5 is a sectional view showing a manufacturing process of the double container.

FIG. 6 is a sectional view showing the same double container.

FIG. 7 is a bottom view showing the same double container.

[Explanation of symbols]

1: multilayer die head, 13: outer layer nozzle, 14: inner layer nozzle, 15: outer layer parison, 15a: opening, 15
b: pinch part, 16: inner layer parison, 16b: pinch part, 16c: large diameter part, 19: air flow path, 24: mold,
24b: concave portion, 25: air blowing device, 26: blowing nozzle, 31: double container, 32: container body, 33: outer layer portion,
34: inner layer, 35: bottom, 37: mouth, 39: vent, 50: air release pin.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takaaki Kato 2-2-1 Fukuura, Kanazawa-ku, Yokohama-shi, Kanagawa F-term in Japan Steel Works, Ltd. (reference) 4F202 AG03 AG07 AH55 CA15 CB01 CB26 CL01 CP01 CP05 4F208 AG03 AG07 AH55 LA01 LA05 LA08 LB01 LB22 LG03 LG06 LG08 LG26 LJ01 LJ09 LJ14 LJ30 LN10

Claims (4)

[Claims] An opening at the lower end of an inner parison (16) is pinched by a pinch portion (16b) in a state of being extruded from a blow molding machine (1), and an opening at a lower end of an outer parison (15). (15a) is pinched by a pinch portion (15b), and an outer layer parison (15) is expanded in a mold (24) to form an outer layer portion (33) having a vent hole (39). By expanding the parison (16) to form the inner layer (34), the inner and outer layers (34,
33) A method for forming a double container (31) in which a space is released, wherein at least one air release pin is provided at a position below the inner parison (16) where the pinch portion (16b) is formed. When (50) is arranged substantially vertically and the inner parison (16) and the outer parison (15) of the length required to form the double container (31) are extruded from the blow molding machine (1), With the air release pin (50) received in the opening (15a) of the outer layer parison (15), the mold (24) is closed, and the mold (2) is closed.
4) The opening (15a) is pinched with the air release pin (50) by the lower part of the molding surface of 4) to form a pinch portion (15b) at a position other than the air release pin (50);
Thereafter, the air vent pin (50) is withdrawn to form a ventilation hole (39) in the outer layer portion (33). 2. The method for forming a double container according to claim 1, wherein a concave portion (24b) for receiving an air release pin (50) is formed on a mold mating surface of the mold (24). 3. After the opening of the inner parison (16) is sandwiched and closed by a pinch (16b), an air release pin (50) is placed below the pinch (16b) of the inner parison (16). 3. The method for forming a double container according to claim 1, wherein the container is arranged at a position. 4. The air vent pin (50) is withdrawn prior to inflating the inner parison (16) to form the inner layer (34). Method of forming a double container.