JP7279025B2 - Injection mold, lip mold included therein, and injection molding method - Google Patents

Description

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

In Patent Document 1, a lip mold divided into left and right parts (in Patent Document 1, " It has been proposed to feed the coolant through the interior of the slide insert mold".

Japanese Patent No. 5540861

By the way, as a method of blow-molding an injection-molded preform, for example, there is a hot parison method (sometimes referred to as a “one-stage method”) in which the injection-molded preform is preheated and blow-molded as it is. and a cold parison type (sometimes referred to as a “two-stage type”) in which an injection-molded preform is cooled and then reheated and blow-molded.

In the hot parison type, the lip mold, which is separate from the cavity mold, is clamped to the cavity mold during injection molding, and after injection molding, the clamping is released and the mold is transported to another device. Compared to the cold parison type, the lip type tends to have more structural restrictions in order to accommodate operations that cannot be taken with the parison type.

In recent years, due to the demand to increase the production volume per unit area, there is a demand for thinning of each part including the lip mold. There was a problem that it was difficult to simply apply the cooling liquid circuit. On the other hand, even with the hot parison type, there are cases where improvement in the cooling efficiency of the neck portion is required in order to manufacture the final molded product in a high cycle.

The present invention has been made in view of the above circumstances. It relates to a lip mold included therein as well as an injection molding method.

An aspect of the present invention for solving the above problems is an injection mold suitable for injection molding a bottomed cylindrical preform having a neck portion on one open end side, wherein the outer peripheral surface of the neck portion and a cavity mold having an engagement recess capable of engaging the lip mold, wherein the lip mold surrounds the outer peripheral surface of the neck portion an annular portion, a tapered portion rising continuously from the annular portion, and the lip-shaped annular portion and the tapered portion are communicated with a predetermined refrigerant supply device when engaged with the engaging recess; and a coolant channel formed including at least 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 that the coolant channel is provided along the circumferential direction of the inner peripheral surface.

Moreover, 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 coolant channel.

Moreover, it is preferable to have at least two or more of the coolant channels.

Moreover, 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 has the coolant channel.

Moreover, when the coolant channel is the first coolant channel, it is preferable that the cavity mold includes a second coolant channel formed including at least part of the surface of the cavity mold.

Moreover, it is preferable that at least a part of the first coolant channel and the second coolant channel overlap.

Another aspect of the present invention for solving the above problems is a lip mold suitable for injection molding the outer peripheral surface of the neck portion of a bottomed cylindrical preform having a neck portion on one open end side. , the lip mold includes an annular portion that can be engaged with the engagement recess of the cavity mold and that surrounds the outer peripheral surface of the neck portion; a taper portion that rises continuously from the annular portion; A coolant flow that communicates with a predetermined coolant supply device when the lip-shaped annular portion and the tapered portion are engaged with the engaging recess, and is formed by including at least a portion of the surface of the annular portion. The lip shape is characterized by comprising: a channel;

Still another aspect of the present invention for solving the above problems is an injection molding method suitable for injection molding a bottomed cylindrical preform having a neck portion on one open end side, comprising: forming an outer peripheral surface of the neck, comprising an annular portion engageable in a recess and surrounding the outer peripheral surface of the neck; and a tapered portion rising continuously from the annular portion. A lip mold is used, and when the annular portion and the tapered portion of the lip mold are engaged with the engaging recess, it communicates with a predetermined refrigerant supply device and includes at least part of the surface of the annular portion. The injection molding method is characterized in that a predetermined coolant is supplied from the coolant supply device to the formed coolant channel.

INDUSTRIAL APPLICABILITY According to the present invention, an injection molding die, a lip mold included therein, and an injection molding method, which can improve the cooling efficiency of the neck portion of a preform in a suitable manner in hot parison injection molding. can be provided.

FIG. 4 is a diagram showing a configuration example of a molded product by the injection blow molding apparatus of Embodiment 1; 1 is a diagram showing a configuration example of an injection blow molding apparatus including the injection molding die of Embodiment 1. FIG. FIG. 2 is a diagram showing a configuration example of an injection molding die according to Embodiment 1; FIG. 4 is a diagram showing a configuration example of a lip mold that constitutes the injection molding die of Embodiment 1; FIG. 4 is a diagram showing a configuration example of a lip mold that constitutes the injection molding die of Embodiment 1; FIG. 4 is a diagram showing a configuration example of a lip mold that constitutes the injection molding die of Embodiment 1; FIG. 4 is a diagram showing a configuration example of a cavity mold that constitutes the injection molding die of Embodiment 1; The figure which shows the structural example of the metal mold|die for injection molding which concerns on a modification.

An embodiment of the present invention will be described below with reference to the drawings. The same members are given the same reference numerals, and the description thereof is omitted as appropriate. The scale and shape of each part in each drawing may be set for convenience.

(Embodiment 1)
FIGS. 1(a) and 1(b) show configuration examples of a preform 1 and a final molded product 5 molded by a hot parison type injection blow molding apparatus I (see FIG. 2). As shown in FIG. 1(a), the preform 1 has a bottomed cylindrical shape with a neck portion 2 on one open end side. 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 maintains the preheating of the injection molded preform 1 and blow molds it as it is, 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 mold 10. As shown in FIG. The injection blow molding apparatus I includes an injection mold 10 (injection molding section 10 ), a temperature control section 30 , a blow molding section 40 and an extraction section 50 . Each part is provided at a position rotated by a predetermined angle (90 degrees in the example of FIG. 2) in the horizontal direction around the transport mechanism 60 . When the injection blow molding apparatus I is composed of only the injection molding section 10 and the blow molding section 40, the injection molding section 10, the blow molding section 40, and the ejection section 50 are arranged at intervals of 180 degrees. They may be provided at positions rotated in the horizontal direction around the conveying mechanism 60 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 process). The temperature control section 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 section 30, the bottom portion 4 of the preform 1 may be pushed down by a predetermined rod member or the like to stretch the preform 1 in the longitudinal direction.

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

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

FIG. 3 is a cross-sectional view showing a configuration example of the injection molding part 10. As shown in FIG. The injection molding part 10 includes a lip mold 11 , a cavity mold 12 and a core mold 13 . The lip mold 11, as shown in FIG. . Further, the lip mold 11 is provided on the transfer plate, and according to the rotation of the transfer mechanism 60, the preform 1 and the final molded product 5 are sequentially transferred while holding the neck portion thereof. The conveying mechanism 60 also serves as an elevating device (not shown) for elevating the lip mold 11 with respect to the cavity mold 12 .

The cavity mold 12 includes a first cavity mold 14 (lip-type contact cavity mold) and a second cavity mold 15 . The first cavity mold 14 is provided on the upper part of the second cavity mold 15 and forms an engaging recess 16 with which the lip mold 11 is engaged. The lip mold 11 is lowered with respect to the first cavity mold 14, and the lip mold 11 is engaged (fitted) with the engagement recess 16, whereby the lip mold 11 is clamped by the first cavity mold 14. become.

The core mold 13 is lowered with respect to the first cavity mold 14 to which the lip mold 11 is clamped. At this time, the lip mold 11, the cavity mold 12 (the first cavity mold 14 and the second cavity mold 15), A space 17 is formed with the core mold 13 . This 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 a lip mold 11 that constitutes the injection molding part 10. As shown in FIG. FIG. 5 is a side view showing a configuration example of a lip mold 11 that constitutes the injection molding part 10. As shown in FIG. FIG. 6 is a cross-sectional view showing a configuration example of the lip mold 11 that constitutes the injection molding part 10, and is a cross-sectional view corresponding to line AA in FIG. The lip mold 11 is composed of a first split mold 11A and a second split mold 11B, which are divided into two equal parts with a cutting line (parting line) extending in the vertical direction. An inner peripheral surface 19 for molding the outer peripheral surface of the neck portion 2 of the preform 1 is formed on each of the split molds 11B. 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 includes an annular portion (thick portion) 20 surrounding the outer peripheral surface of the neck portion 2 and a tapered portion (thin portion) 21 rising continuously 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 expands in diameter as it moves away from the annular portion 20 . The thickness of the vertical cross section of the annular portion 20 is formed to be greater 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 part of the surface thereof. . By supplying a predetermined gas as a coolant to the coolant channel 22, the cooling efficiency of the neck portion 2 of the preform 1 can be improved. Even in hot parison injection molding, improving the cooling efficiency may be advantageous for manufacturing the final molded product 5 in a high cycle. In addition, air is mentioned as gas used as a refrigerant|coolant, for example. However, the refrigerant includes those handled as a liquid, and those 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 in the outer peripheral surface 23 of the annular portion 20 (the peripheral surface on the side opposite to the inner peripheral surface 19 with the annular portion 20 interposed therebetween), and these openings 24 extend into the first refrigerant flow path 22a. are in communication. For example, the opening 24 (opening 24a) communicating with one end side of the first coolant channel 22a is the upstream side (entrance side) of the gas serving as the coolant, and the opening communicating with the other end side of the first coolant channel 22a. 24 (opening 24b) is the downstream side (exit side) of the gas that serves as the refrigerant.

A part of the annular portion 20 is hollow, and the hollow portion serves as a first coolant channel 22a. Also, the first coolant channel 22 a is formed along the circumferential direction of the inner peripheral surface 19 of the lip mold 11 . Furthermore, the first coolant channel 22a is formed in each of the first split mold 11A and the second split mold 11B.

Moreover, a plurality of (here, two) first coolant flow paths 22a are formed in each of the first split mold 11A and the second split mold 11B. All the first coolant channels 22 a are 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 coolant channel 22 is provided at a position as close as possible to the inner peripheral surface 19 of the lip die 11, It is advantageous to increase the contact opportunities (opportunities for heat exchange) between the two and to increase the number of effectively functioning refrigerant flow paths 22 . On the other hand, in order to form such a coolant channel 22, the lip die 11 needs to have a certain thickness due to its structure.

In this 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 made relatively thick. A path 22 is formed. To put it the other way around, the lip mold 11 can secure a space for configuring the coolant flow path 22 precisely because it has the annular portion 20 . Further, even if the annular portion 20 constitutes the coolant channel 22, sufficient strength can be obtained, and furthermore, various modifications and applications of the coolant channel 22 as described above are possible. On the other hand, since the tapered portion 21 tends to be formed thin, it is very difficult to secure a space for configuring the coolant flow path 22 in consideration of strength.

FIG. 7 is a perspective view showing a configuration example of the first cavity mold 14 to which the lip mold 11 of the injection molding part 10 is clamped. As shown in FIG. 7, the first cavity mold 14 is formed with a groove 25 that opens to the inner peripheral surface (the surface of the engaging recess 16). Further, the first cavity mold 14 is provided with through-holes 26 that open to 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 coolant supply device (not shown). It should be noted that the refrigerant supply device may be any device capable of supplying a gas or the like serving as a refrigerant, and conventionally known various devices can be used.

In the injection molding part 10, the lip mold 11 is engaged with the engagement 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 clamped to the first cavity mold 14. Thus, a second refrigerant channel 22b (second gas channel) is formed. The second coolant channel 22 b 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 portion 25 of the first cavity mold 14 faces the opening 24a of the lip mold 11, and the second coolant flow path 22b becomes the first coolant flow path 22a. A cooling channel 22 is formed in communication with the .

In this state, for example, by turning on and off a coolant supply device such as an air jet cooler, it is possible to supply coolant such as cooling gas to the coolant channel 22 or stop the supply. In particular, in the present embodiment, a portion of the second coolant channel 22b (the portion corresponding to the groove portion 25) is also defined by the outer peripheral surface 23 of the lip mold 11. As shown in FIG. That is, the first coolant channel 22a and the second coolant channel 22b partially overlap. In this configuration, the coolant such as gas introduced into the second coolant channel 22b of the first cavity mold 14 is introduced along the outer peripheral surface 23 of the lip mold 11 into the first coolant channel 22a on the lip mold 11 side. be done. Therefore, it is possible to increase the chances of contact between the refrigerant gas and the lip mold 11, so that the cooling efficiency can be easily improved.

In this embodiment, since gas is used as the coolant, water leakage, which occurs when cooling water is used as the coolant, does not occur. In addition, water leakage here means water leakage from the clearance between the lip mold and the cavity mold, or when the mold clamping between the lip mold and the cavity mold is released and the lip mold is separated from the cavity mold. This includes water leakage when the cooling water remaining in the flow path drips. Moreover, by using gas as a coolant, there is no need to provide a water supply and drainage system for supplying cooling water. Even if there is a clearance between the lip mold and the cavity mold, the air cooling system can function effectively. Furthermore, the cooling medium can be supplied and discharged (exchanged) between the lip mold 11 and the cavity mold 12 (first cavity mold 14), which are released (separated) during the molding operation, and the molding machine is greatly modified. there is no need to implement

In the injection molding section 10 , the cavity mold 12 and the core mold 13 are separated from the preform 1 after finishing the injection molding of the preform 1 . That is, the preform 1 is released from the cavity mold 12 and the core mold 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 section 10 to the temperature control section 30 .

The temperature control section 30 adjusts the temperature of the body section 3 of the preform 1 to a predetermined temperature suitable for blow molding. Then, the preform 1 adjusted to the 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 section 40 supplies high-pressure air through the blow core mold to the inside of the preform 1 placed in the blow molding mold, thereby moving the body portion 3 of the preform 1 vertically and horizontally. direction. Thereby, the final molded product 5 is molded.

In the blow molding section 40, the final blow-molded product 5 is then released 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 to finally remove the final molded product 5 from the lip mold 11 .

According to the injection molding part 10, the lip mold 11 included therein, and the injection molding method described above, it is possible to improve the cooling efficiency of the neck part 2 of the preform 1 in a suitable manner in hot parison injection molding. can be done.

(Modification)
FIGS. 8(a), 8(b) and 8(c) show modifications of the injection molded part 10 and the lip mold 11 according to the first embodiment, respectively. For example, as shown in FIG. 8A, grooves 27 may also be formed in the lip mold 11 so as to correspond to the grooves 25 of the first cavity mold 14 . In this configuration, when the lip mold 11 is clamped to the first cavity mold 14, the groove portion 25 of the first cavity mold 14, the groove portion 27 of the lip mold 11, and the through hole 26 define the second coolant flow path 22b. be done.

Alternatively, as shown in FIG. 8B, the first coolant channel 22a and the second coolant channel 22b may be formed linearly. In this case, although the first coolant channel 22a and the second coolant channel 22b do not overlap, it is effective in improving the cooling efficiency of the neck portion of the preform in hot parison injection molding. .

Further, as shown in FIG. 8(c), when the lip mold 11 is clamped to the first cavity mold 14, the contact surface of the second cavity mold 15 that contacts the lip mold 11 (annular portion 20) has a second A concave portion 28 may be formed to serve as one coolant channel 22a. Even in this case, the first coolant channel 22a can be formed including at least part of the surface of the annular portion 20 .

(Other embodiments)
Although the injection molding part 10, the lip mold 11 used therein, and 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 coolant flow path 22 a and/or the second coolant flow path 22 b is merely one aspect, and the first coolant flow path 22 a is the annular portion of the lip mold 11 . 20, and the second coolant channel 22b includes at least part of the surface of the cavity mold 12 (the first cavity mold 14 and/or the second cavity mold 15). It is sufficient if it is formed including

INDUSTRIAL APPLICABILITY The present invention can be used in industrial fields related to injection molds, lip molds thereof, and injection molding methods.

1 preform 2 neck portion 3 body portion 4 bottom portion 5 final molded product 10 injection mold (injection molding portion)
11 Lip mold 11A First split mold 11B Second split mold 12 Cavity mold 13 Core mold 14 First cavity mold (lip mold contact cavity mold)
15 Second cavity mold 16 Engaging concave portion 17 Space 18 Gate 19 Lip mold inner peripheral surface 20 Annular portion (thick portion)
21 taper part (thin part)
22 refrigerant channel (gas channel)
22a first refrigerant channel (first gas channel)
22b second refrigerant channel (second gas channel)
23 Lip-shaped outer peripheral surface 24 Opening 24 a Refrigerant (gas) upstream (inlet side) opening 24 b Refrigerant (gas) downstream (outlet side) opening 25 Groove 26 Through hole 27 Groove 28 Concave portion 30 Temperature control portion Blow molding section 50 Extraction section 60 Conveying mechanism 100 Injection device

Claims (7)

An injection mold suitable for injection molding a bottomed cylindrical preform having a neck portion on one open end,
a lip mold composed of a plurality of split molds for molding the outer peripheral surface of the neck portion;
a cavity mold having an engagement recess capable of engaging the lip mold;
The lip mold is
an annular portion surrounding the outer peripheral surface of the neck;
a tapered portion rising continuously from the annular portion;
Refrigerant formed so as to communicate with a predetermined coolant supply device when the lip-shaped annular portion and the tapered portion are engaged with the engaging recess, and to include at least part of the surface of the annular portion. a flow path ;
When the coolant channel is the first coolant channel,
The cavity mold is
a second coolant channel formed including at least a portion of the surface of the cavity mold;
At least a part of the first coolant channel and the second coolant channel overlap
An injection mold characterized by: The annular portion has an inner peripheral surface corresponding to the outer peripheral surface of the neck portion,
2. The mold for injection molding according to claim 1, wherein the coolant channel is provided along the circumferential direction of the inner peripheral surface. A part of the annular portion is hollow,
3. The mold for injection molding according to claim 1, wherein the hollow portion serves as the coolant channel. 4. The mold for injection molding according to any one of claims 1 to 3, comprising at least two coolant passages. The lip mold is composed of a first split mold and a second split mold,
5. The injection mold according to any one of claims 1 to 4, wherein each of said first split mold and said second split mold is provided with said coolant channel. A lip mold suitable for injection molding the outer peripheral surface of the neck portion of a bottomed cylindrical preform having a neck portion on one open end,
The lip mold is engageable with the engagement recess of the cavity mold, and
an annular portion surrounding the outer peripheral surface of the neck;
a tapered portion rising continuously from the annular portion;
Refrigerant formed so as to communicate with a predetermined coolant supply device when the lip-shaped annular portion and the tapered portion are engaged with the engaging recess, and to include at least part of the surface of the annular portion. a flow path ;
When the coolant channel is the first coolant channel,
At least a portion of the first coolant channel overlaps at least a portion of a second coolant channel formed including at least a portion of the surface of the cavity mold
A lip type characterized by: An injection molding method suitable for injection molding a bottomed cylindrical preform having a neck portion on one open end, comprising:
is engageable with the cavity-type engagement recess, and
an annular portion surrounding an outer peripheral surface of the neck portion;
Using a lip mold for molding the outer peripheral surface of the neck portion, comprising a tapered portion rising continuously from the annular portion,
Refrigerant formed so as to communicate with a predetermined coolant supply device when the lip-shaped annular portion and the tapered portion are engaged with the engaging recess, and to include at least part of the surface of the annular portion. supplying a predetermined coolant from the coolant supply device to the channel;
When the coolant channel is the first coolant channel,
The cavity mold is
a second coolant channel formed including at least a portion of the surface of the cavity mold;
At least a part of the first coolant channel and the second coolant channel overlap
An injection molding method characterized by:

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