JPWO2019208498A1 - Injection molding dies, lip dies included in them, and injection molding methods - Google Patents

Abstract

An injection molding die 10 suitable for injection molding a bottomed tubular preform 1 having a neck portion 2 on one end side of the opening, and a plurality of split molds for molding the outer peripheral surface of the neck portion 2. A lip mold 11 composed of (for example, a first split mold 11A and a second split mold 11B) and a cavity mold 12 having an engaging recess 16 to which the lip mold 11 can be engaged are provided. The eleven engages the annular portion 20 that surrounds the outer peripheral surface of the neck portion 2, the tapered portion 21 that continuously rises from the annular portion 20, and the annular portion 20 and the tapered portion 21 of the lip mold 11 in the engaging recess 16. The configuration includes a refrigerant flow path 22 that communicates with a predetermined refrigerant supply device when combined and is formed including at least a part of the surface of the annular portion 20.

Description

The present invention relates to an injection molding die, a lip mold included therein, and an injection molding method.

Patent Document 1 describes a lip mold that is divided into two left and right (“Patent Document 1”, which is used for injection molding a preform neck portion (referred to as “mouth and neck” in Patent Document 1). It has been proposed to supply the coolant so that it penetrates the inside of the slide insert mold).

Japanese Patent No. 5540861

By the way, as a method of blow-molding an injection-molded preform, for example, a hot parison type (sometimes referred to as a "one-stage type") is used in which the injection-molded preform is blow-molded while maintaining preheating. There is a cold parison type (sometimes referred to as a "two-stage type") in which an injection-molded preform is once cooled and then reheated to be blow-molded.

In the hot parison type, the lip mold, which is different from the cavity mold, is molded into the cavity mold at the time of injection molding, and after the injection molding, the mold clamping is released and the lip mold is transported to another device. Compared to the cold parison type, there are more structural restrictions on the lip type so that it can handle operations that cannot be taken with the parison type.

In recent years, there has been a demand for thinning of each part including the lip type due to a desire to increase the production amount per unit area, and the lip type used in the hot parison type is as described in Patent Document 1. There was a problem that it was difficult to simply apply the coolant circuit. On the other hand, even if it is a hot parison type, it may be required to improve the cooling efficiency of the neck portion in order to manufacture the final molded product in a high cycle.

The present invention has been made in view of the above circumstances, and in injection molding by a hot parison type, an injection molding die and an injection molding die capable of improving the cooling efficiency of the neck portion of the preform in a suitable manner. The lip mold and the injection molding method included therein.

An aspect of the present invention for solving the above problems is an injection molding die suitable for injection molding a bottomed tubular preform having a neck portion on one end side of the opening, and an outer peripheral surface of the neck portion. A lip mold composed of a plurality of split molds and a cavity mold having an engaging recess in which the lip mold can be engaged are provided, and the lip mold surrounds the outer peripheral surface of the neck portion. When the annular portion, the tapered portion that continuously rises from the annular portion, and the lip-shaped annular portion and the tapered portion are engaged with the engaging recess, they communicate with a predetermined refrigerant supply device. The injection molding die is provided with a refrigerant flow path formed by including at least a part of the surface of the annular portion.

Here, it is preferable that the annular portion has an inner peripheral surface corresponding to the outer peripheral surface of the neck portion, and the refrigerant flow path is provided along the circumferential direction of the inner peripheral surface.

Further, it is preferable that a part of the annular portion is formed in a hollow shape, and the portion formed in the hollow shape is used as the refrigerant flow path.

Further, it is preferable to provide at least two or more of the refrigerant flow paths.

Further, it is preferable that the lip mold is composed of a first split mold and a second split mold, and each of the first split mold and the second split mold includes the refrigerant flow path.

Further, when the refrigerant flow path is the first refrigerant flow path, the cavity type preferably includes a second refrigerant flow path formed including at least a part of the surface of the cavity type.

Further, it is preferable that at least a part of the first refrigerant flow path and the second refrigerant flow path overlap.

Another aspect of the present invention for solving the above problems is a lip type of a bottomed tubular preform having a neck portion on one end side of the opening, which is suitable for injection molding the outer peripheral surface of the neck portion. The lip type has an annular portion that can engage with the engagement recess of the cavity type and surrounds the outer peripheral surface of the neck portion, a tapered portion that continuously rises from the annular portion, and the tapered portion. A refrigerant flow formed by communicating with a predetermined refrigerant supply device when the lip-shaped annular portion and the tapered portion are engaged with the engaging recess and including at least a part of the surface of the annular portion. It is in the lip type, which is characterized by having a road.

Yet another aspect of the present invention that solves the above problems is an injection molding method suitable for injection molding a bottomed tubular preform having a neck portion on one end side of the opening, and is a cavity type engagement. The outer peripheral surface of the neck portion is formed so as to be engageable with the recess and to have an annular portion that surrounds the outer peripheral surface of the neck portion and a tapered portion that continuously rises from the annular portion. Using a lip mold, when the annular portion and the tapered portion of the lip mold are engaged with the engaging recess, they communicate with a predetermined refrigerant supply device and include at least a part of the surface of the annular portion. The injection molding method is characterized in that a predetermined refrigerant is supplied from the refrigerant supply device to the refrigerant flow path to be formed.

According to the present invention, in injection molding by a hot parison type, an injection molding die, a lip mold included therein, and an injection molding method capable of improving the cooling efficiency of the neck portion of the preform in a preferable manner. Can be provided.

The figure which shows the structural example of the molded article by the injection blow molding apparatus of Embodiment 1. FIG. The figure which shows the structural example of the injection blow molding apparatus which includes the injection molding die of Embodiment 1. FIG. The figure which shows the structural example of the injection molding die of Embodiment 1. FIG. The figure which shows the structural example of the lip mold which constitutes the injection molding mold of Embodiment 1. FIG. The figure which shows the structural example of the lip mold which constitutes the injection molding mold of Embodiment 1. FIG. The figure which shows the structural example of the lip mold which constitutes the injection molding mold of Embodiment 1. FIG. The figure which shows the structural example of the cavity mold which constitutes the injection molding mold of Embodiment 1. FIG. The figure which shows the structural example of the injection molding die which concerns on the modification.

Hereinafter, one aspect of the present invention will be described with reference to the drawings. The same members are designated by the same reference numerals, and the description thereof is omitted as appropriate. The scale and shape of each part in each figure may be set for convenience.

(Embodiment 1)
1 (a) and 1 (b) show configuration examples of the preform 1 and the final molded product 5 molded by the hot parison type injection blow molding device I (see FIG. 2). As shown in FIG. 1A, the preform 1 has a bottomed tubular shape in which one end side of the opening is a neck portion 2. That is, the preform 1 has a neck portion 2, a body portion 3 continuous with the neck portion 2, and a bottom portion 4 continuous with the body portion 3. The injection blow molding apparatus I blow-molds the injection-molded preform 1 as it is while maintaining the preheating, thereby molding the final molded product 5 as shown in FIG. 1 (b). The final molded product 5 is a resin container used for storing beverages and the like, and is typically a PET bottle.

FIG. 2 is a diagram showing a configuration example of a hot parison type injection blow molding apparatus I including an injection molding die 10. The injection blow molding apparatus I includes an injection molding die 10 (injection molding section 10), a temperature control section 30, a blow molding section 40, and a take-out section 50. Each portion is provided at a position rotated about a transfer mechanism 60 at a predetermined angle (90 degrees in the example of FIG. 2) in the horizontal direction. The injection blow molding apparatus I may be composed of an injection molding unit 10, a blow molding unit 40, and a take-out unit 50 every 180 degrees when it is composed of only an injection molding unit 10 and a blow molding unit 40. It may be provided at a position rotated in the horizontal direction about the transport mechanism 60 at every 120 degrees.

The injection molding unit 10 molds the preform 1 using a resin material such as PET supplied from the nozzle of the injection device 100 as a raw material (injection molding step). The temperature control unit 30 adjusts the temperature of the preform 1 to an appropriate temperature (temperature control step). In addition to adjusting the temperature in the temperature control unit 30, the bottom portion 4 of the preform 1 may be pushed down by a predetermined rod member or the like to extend the preform 1 in the vertical axis direction.

The blow molding unit 40 pushes down the bottom 4 of the preform 1 with a stretching rod to stretch the preform 1 in the vertical axis direction, and blows high-pressure air into the preform 1 to stretch it in the horizontal axis direction. The final molded product 5 is molded (blow molding step). The take-out unit 50 takes out the final molded product 5 to the outside (take-out step).

The transfer mechanism 60 is provided with four transfer plates (not shown), which are the same number as the processing unit including the injection molding unit 10, the temperature control unit 30, the blow molding unit 40, and the take-out unit 50. ing. The transfer mechanism 60 intermittently rotates these transfer plates (rotates in the counterclockwise direction in the example of FIG. 2) and arranges them in the processing unit.

FIG. 3 is a cross-sectional view showing a configuration example of the injection molding unit 10. The injection molding unit 10 includes a lip mold 11, a cavity mold 12, and a core mold 13. As shown in FIG. 4, the lip mold 11 is composed of a plurality of split molds (first split mold 11A and second split mold 11B), and forms the outer peripheral surface of the neck portion 2 of the preform 1. .. Further, the lip mold 11 is provided on the transfer plate, and is sequentially conveyed while holding the neck portion of the preform 1 and the final molded product 5 according to the rotation of the transfer mechanism 60. The transport mechanism 60 also serves as an elevating device (not shown) for elevating and lowering the lip mold 11 with respect to the cavity mold 12.

The cavity type 12 includes a first cavity type 14 (lip type contact cavity type) and a second cavity type 15. The first cavity mold 14 is provided above the second cavity mold 15 and forms an engaging recess 16 with which the lip mold 11 engages. The lip mold 11 is lowered with respect to the first cavity mold 14, and the lip mold 11 is engaged (fitted) with the engaging recess 16 so that the lip mold 11 is molded by the first cavity mold 14. become.

The core mold 13 descends with respect to the first cavity mold 14 in which the lip mold 11 is molded, and at this time, the lip mold 11 and the cavity mold 12 (the first cavity mold 14 and the second cavity mold 15) are A space 17 is formed by the core mold 13. The space 17 is filled with a resin material through a gate 18 provided at the center of the bottom of the second cavity mold 15, whereby the preform 1 can be molded.

FIG. 4 is a perspective view showing a configuration example of the lip mold 11 constituting the injection molding portion 10. FIG. 5 is a side view showing a configuration example of the lip mold 11 constituting the injection molding portion 10. Further, FIG. 6 is a cross-sectional view showing a configuration example of the lip mold 11 constituting the injection molding portion 10, and is a cross-sectional view corresponding to the line AA of FIG. The lip mold 11 is composed of a first split mold 11A and a second split mold 11B, which are bisected with a cutting line (parting line) in the vertical direction, and the first split mold 11A and the second split mold 11A. An inner peripheral surface 19 is formed on each of the split molds 11B to form the outer peripheral surface of the neck portion 2 of the preform 1. The shape of the outer peripheral surface of the neck portion 2 is defined according to the shape of the inner peripheral surface 19 of each of the first split mold 11A and the second split mold 11B.

The lip mold 11 is configured to include an annular portion (thick-walled portion) 20 that surrounds the outer peripheral surface of the neck portion 2, and a tapered portion (thin-walled portion) 21 that continuously rises from the annular portion 20. The annular portion 20 is a plate-shaped member extending in the normal direction of the inner peripheral surface 19. The tapered portion 21 rises from the outer edge of the annular portion 20 to one side (upper side of the paper surface in the examples shown in FIGS. 4 and 5), and the diameter increases as the distance from the annular portion 20 increases. The thickness of the vertical cross section of the annular portion 20 is formed to be larger than the thickness of the horizontal cross section of the tapered portion.

Here, the annular portion 20 is provided with a refrigerant flow path (gas flow path) 22 (first refrigerant flow path 22a (first gas flow path)) including at least a part of the surface thereof. .. By supplying a predetermined gas as a refrigerant to the refrigerant flow path 22, it is possible to improve the cooling efficiency of the neck portion 2 of the preform 1. Even in the injection molding of the hot parison type, it may be advantageous to manufacture the final molded product 5 in a high cycle by improving the cooling efficiency in this way. Examples of the gas serving as the refrigerant include air. However, the refrigerant includes those treated as liquids and those that are gasified by heat in the refrigerant flow path 22, such as low-temperature carbon dioxide gas and liquid nitrogen.

A plurality of openings 24 are provided on the outer peripheral surface 23 of the annular portion 20 (the peripheral surface opposite to the inner peripheral surface 19 with the annular portion 20 interposed therebetween), and these openings 24 are provided in the first refrigerant flow path 22a. Communicating. For example, the opening 24 (opening 24a) communicating with one end side of the first refrigerant flow path 22a is the upstream side (inlet side) of the gas serving as the refrigerant, and the opening communicating with the other end side of the first refrigerant flow path 22a. The 24 (opening 24b) is defined as the downstream side (outlet side) of the gas serving as the refrigerant.

A part of the annular portion 20 is formed in a hollow shape, and the hollow portion thereof is a first refrigerant flow path 22a. Further, the first refrigerant flow path 22a is formed along the circumferential direction of the inner peripheral surface 19 of the lip mold 11. Further, the first refrigerant flow path 22a is formed in each of the first split mold 11A and the second split mold 11B.

Moreover, a plurality (two in this case) of the first refrigerant flow paths 22a are formed in each of the first split mold 11A and the second split mold 11B. Each of the first refrigerant flow paths 22a is formed along the circumferential direction of the inner peripheral surface 19 of the lip mold 11.

In order to improve the cooling efficiency of the neck portion 2 of the preform 1, the refrigerant flow path 22 is provided at a position as close as possible to the inner peripheral surface 19 of the lip mold 11, and the gas serving as the refrigerant and the lip mold 11 are used. It is advantageous to increase the contact opportunity (heat exchange opportunity) of the refrigerant and further increase the number of the refrigerant flow paths 22 that function effectively. On the other hand, in order to form such a refrigerant flow path 22, the lip mold 11 needs to have a certain wall thickness due to its structure.

In the present embodiment, it is noted that the portion (annular portion 20) of the lip mold 11 that surrounds the outer peripheral surface of the neck portion 2 can be formed to have a relatively thick wall, and the refrigerant flow is aimed at here. The road 22 is formed. Conversely, since the lip type 11 includes the annular portion 20, it is possible to secure a space that can form the refrigerant flow path 22. Further, the annular portion 20 has sufficient strength even if the refrigerant flow path 22 is formed, and moreover, various aspects of the refrigerant flow path 22 as described above can be modified and applied. On the other hand, since the tapered portion 21 tends to be formed thin, it is very difficult to secure a space that can form the refrigerant flow path 22 in consideration of the strength.

FIG. 7 is a perspective view showing a configuration example of the first cavity mold 14 in which the lip mold 11 is molded in the injection molding portion 10. As shown in FIG. 7, the first cavity type 14 is formed with a groove portion 25 that opens on the inner peripheral surface (the surface of the engaging recess 16). Further, the first cavity type 14 is provided with through holes 26 which are opened in each of the inner peripheral surface and the outer peripheral surface thereof. One end side of the through hole 26 communicates with the upper end side of the groove portion 25. The side of the through hole 26 opposite to the groove 25 is connected to a predetermined refrigerant supply device (not shown). The refrigerant supply device may be any device that can supply a gas or the like as a refrigerant, and various conventionally known devices can be used.

In the injection molding portion 10, the lip mold 11 is engaged with the engaging recess 16 of the first cavity mold 14, that is, the annular portion 20 and the tapered portion 21 of the lip mold 11 are molded into the first cavity mold 14. As a result, the second refrigerant flow path 22b (second gas flow path) is formed. The second refrigerant flow path 22b is formed by the groove portion 25, the through hole 26, and the outer peripheral surface 23 of the lip mold 11. Further, by engaging the lip mold 11 with the engaging recess 16, the lower end side of the groove 25 of the first cavity mold 14 faces the opening 24a of the lip mold 11, and the second refrigerant flow path 22b becomes the first refrigerant flow path 22a. The cooling flow path 22 is formed in communication with the above.

In this state, for example, by turning on / off the refrigerant supply device such as an air jet cooler, the refrigerant such as cooling gas can be supplied to the refrigerant flow path 22 or the supply thereof can be stopped. In particular, in the present embodiment, a part of the second refrigerant flow path 22b (the portion corresponding to the groove 25) is also defined by the outer peripheral surface 23 of the lip mold 11. That is, a part of the first refrigerant flow path 22a and the second refrigerant flow path 22b overlap. In this configuration, the refrigerant such as gas introduced into the second refrigerant flow path 22b of the first cavity type 14 is introduced into the first refrigerant flow path 22a on the lip type 11 side along the outer peripheral surface 23 of the lip type 11. Will be done. Therefore, the chance of contact between the gas serving as the refrigerant and the lip type 11 can be increased, and it becomes easy to improve the cooling efficiency.

In the present embodiment, since gas is used as the refrigerant, water leakage does not occur as in the case where cooling water is used as the refrigerant, for example. The water leakage referred to here is when water leaks from the clearance between the lip type and the cavity type, or when the mold tightening between the lip type and the cavity type is released and the lip type is separated from the cavity type. Includes water leakage when the cooling water remaining in the flow path drips. Further, by using gas as the refrigerant, it is not necessary to provide a water supply / drainage system for supplying cooling water. Even if there is a clearance between the lip type and the cavity type, the air-cooled type can function effectively. Further, the structure is such that the refrigerant can be supplied / discharged (replaced) between the lip mold 11 and the cavity mold 12 (first cavity mold 14) which are released (separated) during the molding operation, which is a major modification on the molding machine side. There is no need to carry out.

When the injection molding unit 10 finishes injection molding the preform 1, the cavity mold 12 and the core mold 13 are separated from the preform 1. That is, the preform 1 is released from the cavity type 12 and the core type 13. Then, the neck portion 2 of the preform 1 is held by the lip mold 11, and the preform 1 is conveyed from the injection molding portion 10 to the temperature control portion 30.

The temperature control unit 30 adjusts the temperature of the body 3 of the preform 1 to a predetermined temperature suitable for blow molding. Then, the preform 1 adjusted to a predetermined temperature is conveyed from the temperature control section 30 to the blow molding section 40 while being held by the lip mold 11 here as well. The blow molding unit 40 supplies high-pressure air to the inside of the preform 1 arranged in the blow molding mold via the blow core mold to rotate the body 3 of the preform 1 in the vertical axis direction and the horizontal axis. Stretch in the direction. As a result, the final molded product 5 is molded.

The blow molding unit 40 then releases the blow molded final molded product 5 from the blow cavity mold and the blow core mold. With the final molded product 5 held by the lip mold 11, the neck portion moves to the take-out portion 50, and finally the final molded product 5 is removed from the lip mold 11.

According to the injection molding portion 10 described above, the lip mold 11 included therein, and the injection molding method, in the injection molding by the hot parison type, the cooling efficiency of the neck portion 2 of the preform 1 is improved in a preferable manner. Can be done.

(Modification example)
8 (a), 8 (b) and 8 (c) show modified examples of the injection molding portion 10 and the lip mold 11 according to the first embodiment, respectively. For example, as shown in FIG. 8A, the groove portion 27 may be formed in the lip mold 11 so as to correspond to the groove portion 25 of the first cavity mold 14. In this configuration, when the lip mold 11 is molded into the first cavity mold 14, the second refrigerant flow path 22b is defined by the groove portion 25 of the first cavity mold 14, the groove portion 27 of the lip mold 11, and the through hole 26. Will be done.

Further, as shown in FIG. 8B, the first refrigerant flow path 22a and the second refrigerant flow path 22b may be formed linearly. In this case, the first refrigerant flow path 22a and the second refrigerant flow path 22b do not overlap, but are effective in improving the cooling efficiency of the neck portion of the preform in the hot parison type injection molding. ..

Further, as shown in FIG. 8 (c), when the lip mold 11 is molded into the first cavity mold 14, the contact surface of the second cavity mold 15 that comes into contact with the lip mold 11 (annular portion 20) has a second shape. 1 The recess 28 serving as the refrigerant flow path 22a may be formed. Even in this case, the first refrigerant flow path 22a can be formed by including at least a part of the surface of the annular portion 20.

(Other embodiments)
Although the injection molding unit 10, the lip mold 11 used therein, and one aspect of the injection molding method according to the present embodiment have been described above, the present invention is not limited to the above embodiment. In particular, the configuration of the shape, position, number, etc. of the first refrigerant flow path 22a and / or the second refrigerant flow path 22b is only one aspect, and the first refrigerant flow path 22a is an annular portion of the lip type 11. It suffices that it is formed including at least a part of the surface of the 20, and the second refrigerant flow path 22b is at least a part of the surface of the cavity type 12 (first cavity type 14 and / or second cavity type 15). It suffices if it is formed including.

The present invention can be used in the industrial fields related to injection molding dies, lip dies thereof, and injection molding methods.

1 Preform 2 Neck part 3 Body part 4 Bottom part 5 Final molded product 10 Injection molding mold (injection molding part)
11 Lip type 11A 1st split type 11B 2nd split type 12 Cavity type 13 Core type 14 1st cavity type (lip type contact cavity type)
15 Second cavity type 16 Engagement recess 17 Space 18 Gate 19 Lip type inner peripheral surface 20 Circular part (thick wall part)
21 Tapered part (thin wall part)
22 Refrigerant flow path (gas flow path)
22a 1st refrigerant flow path (1st gas flow path)
22b Second refrigerant flow path (second gas flow path)
23 Lip-shaped outer peripheral surface 24 Opening 24a Opening on the upstream side (inlet side) of the refrigerant (gas) 24b Opening on the downstream side (outlet side) of the refrigerant (gas) 25 Groove 26 Through hole 27 Groove 28 Recess 30 Temperature control part 40 Blow molding part 50 Extraction part 60 Conveyance mechanism 100 Injection device

Claims (9)

An injection molding die suitable for injection molding a bottomed tubular preform having a neck on one end side of the opening.
A lip mold composed of a plurality of split molds for forming the outer peripheral surface of the neck portion, and a lip mold
A cavity type having an engaging recess into which the lip type can be engaged is provided.
The lip type is
An annular portion that surrounds the outer peripheral surface of the neck portion and
A tapered portion that continuously rises from the annular portion and
A refrigerant that communicates with a predetermined refrigerant supply device when the lip-shaped annular portion and the tapered portion are engaged with the engaging recess, and is formed including at least a part of the surface of the annular portion. A mold for injection molding, which comprises a flow path. The annular portion has an inner peripheral surface corresponding to the outer peripheral surface of the neck portion.
The injection molding die according to claim 1, wherein the refrigerant flow path is provided along the circumferential direction of the inner peripheral surface. A part of the annular portion is formed in a hollow shape.
The injection molding die according to claim 1 or 2, wherein the hollow portion is used as the refrigerant flow path. The injection molding die according to any one of claims 1 to 3, further comprising at least two or more of the refrigerant flow paths. The lip mold is composed of a first split mold and a second split mold.
The injection molding die according to any one of claims 1 to 4, wherein each of the first split mold and the second split mold includes the refrigerant flow path. When the refrigerant flow path is the first refrigerant flow path,
The cavity type
The injection molding die according to any one of claims 1 to 5, further comprising a second refrigerant flow path formed by including at least a part of the surface of the cavity mold. The injection molding die according to claim 6, wherein at least a part of the first refrigerant flow path and the second refrigerant flow path overlap. A lip type suitable for injection molding the outer peripheral surface of the neck portion of a bottomed tubular preform having a neck portion on one end side of the opening.
The lip type can be engaged with the engagement recess of the cavity type, and
An annular portion that surrounds the outer peripheral surface of the neck portion and
A tapered portion that continuously rises from the annular portion and
A refrigerant that communicates with a predetermined refrigerant supply device when the lip-shaped annular portion and the tapered portion are engaged with the engaging recess, and is formed including at least a part of the surface of the annular portion. A lip type characterized by having a flow path. It is an injection molding method suitable for injection molding a bottomed tubular preform whose neck is on one end side of the opening.
Cavity type engagement It is possible to engage with the recess and
An annular portion that surrounds the outer peripheral surface of the neck portion and
Using a lip mold for forming the outer peripheral surface of the neck portion, which comprises a tapered portion that continuously rises from the annular portion.
A refrigerant that communicates with a predetermined refrigerant supply device when the lip-shaped annular portion and the tapered portion are engaged with the engaging recess, and is formed including at least a part of the surface of the annular portion. An injection molding method comprising supplying a predetermined refrigerant from the refrigerant supply device to the flow path.

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