JP3281073B2 - Injection stretch blow molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection method in which at least one cycle of a molding process such as injection molding, stretch blow molding and mold release is continuously performed by moving a lip mold holding a preform. The present invention relates to a stretch blow molding machine, and particularly to an injection stretch blow molding machine in which cooling of a lip mold is devised.

[0002]

2. Description of the Related Art Conventionally, as this kind of injection stretch blow molding machine, a preform is manufactured by injection molding a plastic, and the preform is supercooled to an amorphous state during the injection molding, and then the preform is formed. A two-stage injection stretch blow molding machine that pre-heats to the stretch molding temperature and then performs blow molding with another device, and an injection molded preform in the same device while retaining the heat during the injection molding. There is known a one-stage injection-stretch blow molding machine for performing blow molding at a time.

[0003] Of these injection stretch blow molding machines, one-
Stage injection stretch blow molding machine has a small installation area,
In addition, since it is advantageous in terms of thermal efficiency and productivity, it has been widely used in the production of plastic containers.

More specifically, this one-stage injection stretch blow molding machine realizes one cycle of a molding process at least in an injection molding station, a stretch blow molding station and a molded product release station. In the station, the cavity mold and the core mold are cooled when the preform is injection-molded, and the lip mold for forming the lip portion of the preform is brought into contact with the cavity mold and the core mold to be cooled.

After the injection molding, the preform is moved to a blow mold of a stretch blow molding station while holding the lip portion of the preform by a lip mold, stretch blow-molded, and the lip portion is formed by a lip mold. In this state, the molded product is moved from the stretch blow molding station to the molded product release station, the lip is opened, and the molded product is taken out.

In some cases, a temperature control station for controlling the temperature of a preform to a temperature suitable for stretch blow molding is provided between the injection molding station and the stretch blow molding station. In some cases, in order to improve the heat resistance of a molded article, a blow cavity mold is heated in a stretch blow molding station, and the blow-molded article is heat-set.

[0007]

In the conventional one-stage injection stretch blow molding machine, the lip mold is cooled only when the lip mold is in contact with the cavity mold or the core mold in the injection molding station. In such a state, when trying to shorten the molding cycle, there is not enough cooling time between the previous injection molding and the next injection molding, and the lip type If the next injection molding is performed as it is, insufficient cooling of the lip may cause voids in the thick lip, deformation at the time of release, or near the lip. However, there is a problem that a whitening phenomenon occurs.

Also, when the preform is heated at a temperature control station other than the injection molding station, or when the blow cavity mold of the stretch blow molding station is heated, the lip portion is also heated, thereby shortening the cycle. As in the case of the formation, there is a problem that the generation, deformation or whitening of the void may occur.

Therefore, an object of the present invention is to reduce the occurrence of voids, deformation or whitening in the neck even when shortening the molding cycle or reheating the preform after the injection molding station. An object of the present invention is to provide a one-stage injection stretch blow molding machine capable of preventing the occurrence.

[0010]

An injection stretch blow molding machine according to a first aspect of the present invention includes at least an injection molding station, a stretch blow molding station, and a molded article release station, each of which includes a lip portion of a preform. and a lip mold by circulating movement for holding, in an injection stretch blow molding machine for carrying out the molding process of a cycle, the
Blow cavity mold installed in stretch blow molding station
The lip mold is used as a refrigerant at the contact portion with the lip mold.
A cooling block for cooling the blow cavity;
Heating means for heat setting is built in the mold,
Form a heat insulating part between the lock and the blow cavity mold.
It is characterized by having achieved.

[0011] An injection stretch blow molding machine according to a second aspect of the present invention comprises:
At least an injection molding station, a temperature control station,
Stretch blow molding station and molded product release station
Each of these stations has a preform
Circulates the lip that holds the
In the injection stretch blow molding machine to carry out the molding process, prior to
The lip type of temperature control pot provided at the temperature control station
Cooling to cool the lip type with a refrigerant
Providing a block, the cooling block and the temperature control pot,
A heat insulating portion is formed between the two.

[0012]

[0013]

[0014]

[0015]

In the injection stretch blow molding machine according to the first aspect of the present invention, after the injection molding of the preform in the injection molding station, the lip mold for holding the lip portion of the preform is formed by the stretch blow molding station and the molded product release. during the circulating movement of the station, placed <br/> the stretch blow molding station Te, by cooling the cooling block said lip mold, it is possible to cool the lip mold to return to the injection molding station for the next cycle . Therefore, even if the molding cycle is shortened, the lip mold can be sufficiently cooled before reaching the injection molding station of the next cycle, and the occurrence and deformation of the lip portion due to insufficient cooling of the lip mold can be achieved. Alternatively, the occurrence of the whitening phenomenon can be prevented.

In the stretch blow molding station,
A cooling block is provided in the contact portion with the blow cavity type lip mold, and the coolant is supplied to this cooling block. Blow cavity
Type contacting the lip mold to the cooling block when installing the preform can be cooled. Therefore, cooling can be performed simply and inexpensively.

Furthermore , when heat-setting the preform with a blow cavity mold to improve the heat resistance of the molded article, heat is conducted from the blow cavity mold to the lip mold to reheat the lip. However, by providing a cooling block as described above, the lip mold is kept in a cooled state, even if heat setting is performed, and the occurrence of voids, deformation or whitening of the lip portion is prevented. It is possible to do.

Further, between the cooling block and the blow cavity mold, by forming the heat-insulating portion, minimizing heat transfer to the blow cavity mold or et cooling block during heat setting process, the lip mold in the cooling block It is possible to improve the cooling efficiency, thereby making it possible to further prevent the generation, deformation or whitening of the lip portion.

[0019] In the injection stretch blow molding machine according to the second invention, the contact portion of the lip-type temperature regulating pot in temperature control station, a cooling block, supplies a coolant to the cooling block. Therefore, even when the preform is installed in the temperature control pot and preheating is performed, the cooling can be performed by bringing the lip into contact with the cooling block, thereby generating voids, deformation, or whitening of the lip portion. Can be prevented from occurring.

Further, between the cooling block and the temperature control pot, by forming the heat-insulating portion, minimizing heat transfer to the temperature control pot or et cooling block, thereby improving the cooling efficiency of the lip mold in the cooling block Accordingly, it is possible to further prevent the generation, deformation, or whitening of voids in the lip portion.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments to which the present invention is applied will be specifically described below with reference to the drawings.

1 to 6 show an injection stretch blow molding machine according to one embodiment of the present invention.

This injection stretch blow molding machine is for molding a plastic container made of, for example, polyethylene terephthalate (PET). As shown in FIG. 1, an injection molding station 10 for performing injection molding of a preform.
A stretch blow molding station 12 for performing stretch blow molding of a preform to form a plastic container having a predetermined shape; and a molded product release station 14 for releasing a plastic container, which is a molded product, from the mold. 3
It belongs to the station.

In addition, the injection molding station 10, the stretch blow molding station 12, and the molded article release station 1
Three lip-type transfer plates 16 are provided corresponding to the four stations. A lip-type support plate 18 is attached to each lip-type transfer plate 16, and a lip 20 is attached to the lip-type support plate 18, so that the lip portions of the preform are held by these lip-types. . Then, the lip mold 20 holding the preform is rotated by the rotation of the lip mold transfer plate 16 so that each of the stages 10, 12,
14 is circulated to perform one cycle of the molding process.

As shown in FIG. 2, the lip-type support plate 18 is formed in a rectangular shape in which two elongated divided plates 22 are joined in the width direction. In addition, each divided plate 2
Two support portions 24 of the lip mold 20 are formed at the positions corresponding to the two mating surfaces, and the split lip molds 20 are mounted in the support portions 24, respectively. further,
Wedge holes 26 are formed in the mating surfaces of both ends of the split plate 22 for inserting an ejection cam (not shown) for separating the lip mold 20.

In the injection molding station 10, as shown in the mold clamping state in FIG. 3, the lower part of the injection cavity mold 28 in which the split mold is clamped is brought into close contact with a hot runner mold (not shown).
The mold is clamped in a state of being in close contact with the injection molded core mold 30 with the lip mold 20 supported on the lip mold support plate 18 at the upper part therebetween.

Further, cooling water channels 32 and 34 are formed in the injection cavity mold 28 and the injection core mold 30. By supplying cooling water into the channels 32 and 34, the injection cavity mold 28 and the injection core mold 30 are cooled. The injection core mold 30 is cooled.

Then, the molten resin is injected into the mold from the injection machine through a hot runner mold, and rapidly cooled with the cooling water to form a bottomed cylindrical shape having a lip portion 36 at an upper portion and a predetermined thickness. The preform 38 is formed. The lip portion 36 is also cooled and maintains a predetermined shape because the lip mold 20 is in contact with the injection cavity mold 28 and the injection core mold 30.

At the stretch blowing station 12, as shown in FIG. 4, the preform 38 molded at the injection molding station 10 is moved with the lip portion 36 held by the lip mold 20 and the lip support plate 18 and the lip. It is transferred via the mold transfer plate 16 and inserted into the blow cavity mold 40 from above. In the blow cavity mold 40, a split mold 46 is divided so as to be able to be divided into right and left, and an upper bottom mold 41 is combined with a bottom portion.

A blow core mold and a stretch rod (not shown) are clamped from above the lip mold 20 so as to be positioned inside the preform 38, and the stretch rod is used to extend the preform 38 in the longitudinal axis direction. Compressed air is blown into the preform 38 by the mold to extend in the horizontal axis direction, and the preform 38 is formed into a predetermined container shape along the shape of the blow cavity mold.

Further, a heater 42 is incorporated in the blow cavity mold 40. The heater 42 heats the preform 38 at the time of blow molding, thereby making the preform 38 uniform in thickness and storing the heated filling in a container. A heat-setting process is performed to prevent deformation of the container when filled into the inside and to improve heat resistance.

For this heat setting process, the heater 4
When the blow cavity mold 40 is heated in step 2, the lip mold 20 that is in contact with the blow cavity mold 40 is heated by heat conduction, and the thick lip portion 36 is heated. Is likely to occur.

Therefore, a cooling block 44 is provided at a contact portion of the blow cavity mold 40 with the lip mold 20, and
The lip mold 20 is cooled.

Specifically, at the center of the upper surface of the split mold 46,
A rectangular concave portion 48 is formed, and a rectangular cooling block 44 formed in a divided shape like the split mold 46 is fitted in the rectangular concave portion 48.

At the center of the cooling block 44, as shown in FIGS. 5 and 6, a through-hole 50 for inserting a preform corresponding to the shape of the lip 20 is formed. It comes in contact with.

A cooling water passage 54 is formed in a substantially rectangular shape around the through hole 50 of each cooling block 44. To cool the lip mold 20 and also to prevent the lip portion 36 from being affected by heating during the heat setting process.

Further, a heat insulating groove 56 is formed on the bottom surface of the cooling block 44 along the outer periphery of the through hole 50 and in a cross shape outward from the outer periphery. The cooling section 44 is configured to improve the cooling efficiency of the cooling block 44. by this,
It is possible to further prevent the lip portion 36 from being affected by heating during the heat setting process.

As described above, by utilizing the contact of the lip mold 20 with the blow cavity mold 40 during blow molding,
Since the lip portion 36 is cooled, it is not necessary to newly provide a cooling device, and the existing blow cavity mold 4 can be cooled.
It is only necessary to add the cooling block 44 to 0, the structure is simple, and the cost can be reduced.

In the molded article releasing station 14, the plastic container having a predetermined shape molded in the stretch blow molding station 12 is moved to the lip portion 36 by the lip mold 2.
After being transported via the lip-type support plate 18 and the lip-type transport plate 16 while being held at 0, when reaching a predetermined position, an eject rod (not shown) is inserted into the plastic container from above the lip type 20 and The eject cam descends into the wedge hole 26 of the lip-type support plate 18 to separate the split plate 22 of the lip-type support plate 18 and the lip 20 together. Then, the lip portion 36 whose position is regulated by the eject rod is released from the lip mold 20, dropped and taken out. Then, the empty lip mold 20 is transferred to the injection molding station 10, and the same operation as described above is repeated.

FIGS. 7 and 8 show an injection stretch blow molding machine according to another embodiment of the present invention.

In this embodiment, as shown in FIG. 7, the injection molding station 10, the stretch blow molding station 1
2. In addition to the molded article release station 14, a four-station one having a temperature control station 60 between the injection molding station 10 and the stretch blow molding station 12 for preheating the preform so that it can be blow molded. I have. In this embodiment, the injection molding station 10, the stretch blow molding station 12, and the molded article release station 14 are the same as those in the above embodiment except that the heat setting process is not performed in the stretch blow molding station 12. It has a similar configuration.

Then, at the temperature control station 60, FIG.
As shown in FIG. 3, the preform 38 molded in the injection molding station 10 has a lip 36
Is transported through the lip-type support plate 18 and the lip-type transfer plate 16 while being held at the temperature adjusting station 60, and inserted into the temperature adjusting pot 62 installed at the temperature adjusting station 60 from above.

The temperature control pot 62 has a plurality of heating blocks 66, 6 inside which a flow path 64 for hot water, heating oil or the like is formed.
8, 70 are stacked and a plurality of upper and lower heating blocks 66, 6 are stacked.
Hot water or heating oil at different temperatures is supplied to each of the preforms 8 and 70 to heat the internal preform 38 in the axial direction with an optimum temperature distribution for blow molding.

As described above, when the preform 38 is heated after the lip portion 36 is cooled in the injection molding station 10, the lip portion 36 is also heated via the lip mold 20 in contact with the temperature control pot 62, and the generation and deformation of voids Or it may cause the whitening phenomenon.

Therefore, a cooling block 72 is provided on the uppermost heating block 66, which is the contact portion of the temperature control pot 62 with the lip mold 20, so that the lip mold 20 is cooled.

A through hole 74 corresponding to the shape of the lip 20 is formed at the center of the cooling block 72.
It comes in contact with.

A cooling water flow path 76 is formed around the through hole 74 of each cooling block 72.
By supplying cooling water to the inside, the lip mold 20 is cooled via the cooling block 72, and the influence on the lip portion 36 due to heating during temperature control is prevented.

Further, a heat insulating material 78 is provided between the cooling block 72 and the heating block 66,
2 to improve the cooling efficiency. This makes it possible to further prevent the lip portion 36 from being affected by heating during temperature control. In addition, as the heat insulating material 78,
For example, a synthetic resin plate such as bakelite, a polyamide-based synthetic polymer (trade name: Nomex), or the like can be used.

As described above, the temperature control pot 6 during the temperature control is used.
The cooling of the lip portion 36 is performed by utilizing the contact of the lip mold 20 with the lip 2, so that it is not necessary to provide a new cooling device, and only the cooling block 72 is added to the existing temperature control pot 62. And the structure is simple, and the cost can be kept low.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

For example, in the embodiment shown in FIGS. 1 to 6, the case where the heat setting process is performed in the stretch blow molding station 12 has been described. However, the present invention is not limited to this case.
Blow cavity mold 4 without heat setting
0 may be provided with a cooling block 44. In this case, the molding cycle can be shortened by cooling the lip mold 20 before the next injection molding.

Further, in each of the above embodiments, the case where the lip mold is cooled only at one of the stretch blow molding station and the temperature control station has been described. However, the present invention is not limited to this example. Can cool the lip mold in both the stretch blow molding station and the temperature control station, and this is particularly effective when the heat setting process is performed in the stretch blow molding station.

Further, the present invention is not limited to the case where the lip mold is cooled at the temperature control station or the stretch blow molding station. The lip mold is cooled by blowing cooling air to the lip mold using an air nozzle or the like at the molded product release station. In this case, the lip mold can be cooled immediately before the next injection molding, which is useful for shortening the molding cycle.

[0054]

As described above, according to the injection stretch blow molding machine of the first invention, even if the molding cycle is shortened, it is sufficient to reach the injection molding station in the next cycle. The lip mold can be cooled, and it is possible to prevent the occurrence of voids, deformation or whitening of the lip due to insufficient cooling of the lip mold.

Further, when the preform is installed in the blow cavity mold , the lip mold can be cooled by contacting the cooling block, so that cooling can be performed simply and inexpensively. Further
In addition, even when the heat setting process is performed in the blow cavity mold , there is an effect that the lip mold can be kept in a cooled state and the occurrence of voids, deformation or whitening of the lip portion can be prevented.

[0056] Further, to suppress the thermal conduction from the blow cavity mold during heat setting process to the cooling block as much as possible, it is possible to improve the cooling efficiency of the lip mold in the cooling block, more generation and deformation or whitening of the void of the lip There is an effect that occurrence of the phenomenon can be prevented.

According to the injection stretch blow molding machine of the second invention, even when the preform is installed in the temperature control pot and preheating is performed, the cooling can be performed by bringing the lip mold into contact with the cooling block. Thus, there is an effect that generation, deformation, or whitening of the lip portion can be prevented.

[0058] In addition, minimizing heat transfer to the temperature control pot or et cooling block, it is possible to improve the cooling efficiency of the lip mold in the cooling block, the occurrence of generation or deformation or whitening of voids further lip There is an effect that it can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a schematic configuration of an injection stretch blow molding machine according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a lip type support plate for holding a lip type in the injection stretch blow molding machine shown in FIG.

FIG. 3 is a cross-sectional view showing a state of an injection mold of the injection stretch blow molding machine shown in FIG.

FIG. 4 is a sectional view showing a state of a blow cavity type of the injection stretch blow molding machine shown in FIG. 1;

FIG. 5 is an enlarged cross-sectional view of a stretch blow type cooling block shown in FIG. 4;

FIG. 6 is a bottom view showing a heat insulating structure of the cooling block of FIG. 5;

FIG. 7 is an explanatory diagram showing a schematic configuration of an injection stretch blow molding machine according to another embodiment of the present invention.

FIG. 8 is a sectional view showing a state of the temperature control pot of FIG. 8;

DESCRIPTION OF SYMBOLS 10 injection molding station 12 stretch blow molding station 14 molded product release station 20 lip mold 36 lip part 38 preform 40 blow cavity mold 44 cooling block 46 split mold 56 heat insulating groove 60 temperature control station 72 cooling block 78 Insulation

Claims (2)

(57) [Claims] 1. A molding machine comprising at least an injection molding station, a stretch blow molding station, and a molded article release station, in each of which a lip mold holding a lip portion of a preform is circulated to perform a one-cycle molding process. In the injection stretch blow molding machine to be implemented, a blow cavity provided in the stretch blow molding station is provided.
The lip mold is cooled at the contact portion of the lip mold with the lip mold.
A cooling block for cooling with a medium is provided, and a heating means for heat setting is provided on the blow cavity mold.
Built-in, the cooling block and the blow cavity mold
Injection stretching characterized by forming a heat insulating part between
Blow molding machine. 2. At least an injection molding station, temperature control
Station, stretch blow molding station and molded product release
Mold stations, each of which has a pre-
Circulate the lip that holds the lip of the foam
Injection-stretch blow-molding to carry out one cycle of molding process
A lip of a temperature control pot provided at the temperature control station.
Cooling the lip mold with a refrigerant at the contact portion with the mold
A cooling block is provided, and a heat insulating portion is provided between the cooling block and the temperature control pot.
An injection stretch blow molding machine characterized by being formed.