JP2021137965A - Preform molding apparatus - Google Patents

Abstract

To manufacture a hollow molded body with no whitening at a gate part and no stringing, by a preform molding apparatus in which disk-shaped heat insulating paper having a simple shape is sandwiched between a circular recess on a cavity mold side and a tip of a hot runner nozzle to be inserted into the circular recess, and a space between a resin part of the gate part of a preform and a resin part located on the heat insulating paper side is properly divided so that the preform in a state capable of being blow-molded can be released from the mold.SOLUTION: A thickness of heat insulating paper 12 is set to a thickness at which a resin melt layer 18 and a resin heat insulating layer 19 are formed in an aperture 15 of the heat insulating paper 12, and a circular opening of the aperture 15 is set into width enough to exchange heat to maintain in a solidified state in which a resin located in the resin heat insulating layer 19 that exchanges heat with the resin molten layer 18 is in contact with a recess inner top surface 10 of a circular recess 6 of a cavity mold 5.SELECTED DRAWING: Figure 1

Description

The present invention relates to a preform molding apparatus in an injection stretch blow molding machine in which an injection-molded preform is released from a mold and then stretch-blow molded to obtain a hollow molded body, and the hollow molded body is taken out.

In the injection stretch blow molding machine, a resin is injected from an injection device to inject and mold a preform, and a preform released from the injection mold of the injection molding part is stretch blown by a blow molding die. A stretch blow molding section for obtaining a hollow molded body by molding, and a take-out section for removing the hollow molded body from the blow molding die of the stretch blow molding section and taking it out so that it can be sent out of the molding machine. Some have two stages.

In the injection molding section of the injection stretch blow molding machine, a hot runner device that branches the molten resin sent from the injection device into a plurality of runners and a hot runner device located above the hot runner device, and preforms corresponding to each runner are provided. A preform molding apparatus is composed of an injection molding die composed of a mold for injection molding.

The injection molding mold in this preform molding device includes a lip mold that forms the shape of the outer peripheral surface of the mouth of the preform and also serves to convey the injection-molded preform, and the outer peripheral surface shape and bottom of the body of the preform. The cavity type that forms the outer surface shape and the core type that forms the inner surface shape from the mouth to the bottom of the preform are combined.

As shown in FIG. 2, the hot runner device 2 of the preform molding device 1 has a hot runner nozzle 3 erected, and although not shown, the hot runner nozzles 3 are arranged in a state where a plurality of the hot runner nozzles 3 are erected. ing. The cavity mold 5 of the injection molding mold 4 is mounted on the hot runner device 2 via a connecting plate 2a, and the tip of the hot runner nozzle 3 is formed in a circular recess 6 recessed in the lower surface of the cavity mold 5. Part 7 is intruded. A cavity gate 8 that tapers downward reaches the center of the circular recess 6.

A heat insulating member 9 having an opening 15 (see FIG. 3) is sandwiched between the circular recess 6 on the lower surface of the cavity type 5 and the tip portion 7 of the hot runner nozzle 3. The heat insulating member 9 is used for the purpose of making it difficult for heat to propagate between the high temperature hot runner nozzle 3 and the cavity type 5, and also serves as a sealing member for preventing resin leakage.

That is, in the injection stretch blow molding machine, high-temperature molten resin is injected from the injection device into the injection molding mold through the hot runner device, and the hot runner nozzle portion is also heated to a high temperature in order to maintain the molten state of the resin. It is maintained, but on the other hand, the cavity mold is cooled in order to quickly mold the resin fed into the injection mold from the nozzle port of the hot runner nozzle into a preform.

Then, the cooling on the injection molding die side does not affect the tip of the hot runner nozzle, and the heat from the hot runner nozzle side does not impair the cooling of the molten resin injected into the injection molding die. There is a need to. Therefore, the heat insulating member is sandwiched between the cavity-type circular recess and the tip of the hot runner nozzle.

The injection stretch blow molding machine is a molding machine that manufactures a hollow molded body by a hot parison type molding method in which a preform released from an injection molding die is stretch blow molded by a blow molding die as described above. Is. Therefore, the preform is released from the injection molding mold at the timing when the mold does not lose its shape even when the mold is released and the blow molding can be performed.

Further, as a technique using a heat insulating member, as shown in FIG. 4 of Patent Document 1, which is an earlier application of the applicant of the present application, between the recess on the lower surface of the cavity type and the tip of the hot runner nozzle. A technique is shown in which a disk-shaped heat insulating member is sandwiched between the two.

Further, as a technique using a heat insulating member, the document is that a bowl-shaped heat insulating member is sandwiched between a concave curved surface portion of a concave portion on the lower surface of a cavity type and a convex curved surface portion of a tip portion of a hot runner nozzle. There is Patent Document 2 shown as FIG. 2 in the inside.

Similarly, as a technique using a heat insulating member, Patent Document 3 shows that a shallow pot-shaped heat insulating member is sandwiched between a concave portion of a concave portion on the lower surface of a cavity type and a tip portion of a hot runner nozzle. There is.

Japanese Unexamined Patent Publication No. 2004-025812 (Fig. 4) Japanese Unexamined Patent Publication No. 2000-351151 (Fig. 2) Japanese Unexamined Patent Publication No. 2002-316342

In the cap-shaped heat insulating member shown in Patent Document 2 and the shallow pot-shaped heat insulating member shown in Patent Document 3, the shape of the heat insulating member is complicated, and the manufacturing of the heat insulating member itself is costly. There is.

The heat insulating member shown in Patent Document 1 has a disk shape, and if the shape is compared with that of the heat insulating member shown in Patent Documents 2 and 3, it has a simple shape and can be produced with a good yield. It is a heat insulating member that can be used.

In the above-mentioned preform forming apparatus 1 shown in FIGS. 2 and 3, the inner top surface 10 of the circular hole-shaped concave portion 6 of the cavity type 5 is a flat surface, and the hot runner nozzle 3 of the hot runner apparatus 2 has a flat surface. The tip end surface 11 of the tip portion 7 is a flat surface.

Then, as shown in FIG. 3, in the preform molding apparatus 1, a disk-shaped heat insulating member 9 is formed between the concave inner top surface 10 on the cavity mold 5 side and the tip end surface 11 on the hot runner nozzle 3 side. The heat insulating paper 12 is placed on the lower side, and the stainless steel heat insulating plate 13 is placed on the upper side in a superposed state.

Of course, the heat insulating paper 12 and the heat insulating plate 13 used in the above combination have an opening 15 corresponding to the gate opening 14 (diameter about 2 mm) at the lower end of the cavity gate 8. The diameter of the opening 15 of the heat insulating plate 13 is set to, for example, the same diameter as or smaller than the diameter of the gate opening 14, and the diameter of the opening 15 of the heat insulating paper 12 is set to be smaller than, for example, the diameter of the gate opening 14. It was about 4 mm. Then, the inner top surface 10 of the recess on the cavity type 5 side and the tip end surface 11 on the hot runner nozzle 3 side are arranged so that the thickness t of the heat insulating paper 12 and the heat insulating plate 13 is about 0.4 mm. It is compressed by two flat surfaces.

The reason why the heat insulating paper 12 and the heat insulating plate 13 are overlapped to form the heat insulating member 9 is that when the heat insulating paper 12 is used alone, the molten resin repeatedly passes through the heat insulating paper 12 to open holes 15. This is because the diameter is gradually increased, and the expansion of the opening 15 of the heat insulating paper 12 is prevented by superimposing the metal heat insulating plate 13 on the heat insulating paper 12.

In the preform molding apparatus in which the preform is injection-molded in this way and the preform is released so that the preform can be transferred to the stretch blow molding mold in a short time, the heat insulating member 9 is formed in a disk shape. board.

However, in the preform molding apparatus 1, when the preform is released at the timing when blow molding becomes possible, the resin at the gate portion of the preform and the resin in the opening 15 of the heat insulating member 9 are properly used. There was a case where stringing occurred at the gate part without separating.

Under the condition that the mold can be released in a state where blow molding is possible, as a measure to prevent the stringing itself, the opening 15 of the heat insulating member 9 is made small in diameter, but the opening is made. When the diameter of 15 was reduced, it became difficult for the molten resin to be sent from the hot runner nozzle to the injection molding die. In addition, there is a problem that the gate portion of the preform is whitened.

Therefore, in view of the above circumstances, in view of the above circumstances, a disc-shaped heat insulating paper having a simple shape is sandwiched between the circular recess on the cavity type side and the tip of the hot runner nozzle to be inserted into the circular recess. With the preform molding device, the preform that can be blow-molded can be separated properly between the resin part of the gate part of the preform and the resin part located on the heat insulating paper side so that the preform can be separated. An object of the present invention is to produce a hollow molded product in which the gate portion is not whitened and there is no stringing.

(Invention of claim 1)
The present invention has been made in consideration of the above problems, and is tapered downward into a hot runner device in which a plurality of hot runner nozzles are erected and a circular concave portion into which the tip of the hot runner nozzles enters. It has a cavity type that the cavity gate has reached, and the resin injected from the hot runner nozzle side through the cavity gate is molded into a preform, and after the injection molding, the preform is released in a state where blow molding is possible. In a preform molding apparatus including an injection molding mold to be molded,
The inner top surface of the cavity-shaped circular recess is a flat surface, and the end surface of the tip of the hot runner nozzle is a flat surface.
A disk-shaped heat insulating paper having a hole in the center is fitted into the cavity-shaped circular hole-shaped recess, and the gate opening of the cavity gate is located at the center of the hole in the heat insulating paper.
The heat insulating paper is sandwiched between the flat surface of the inner top surface of the cavity-shaped circular recess and the flat surface of the tip end surface of the tip of the hot runner nozzle so as to be compressible and deformable.
The heat insulating paper sandwiched between the cavity-type circular recess and the tip of the hot runner nozzle that has entered the circular recess is
The nozzle port of the hot runner nozzle and the cavity gate are surrounded by the flat surface of the inner top surface of the cavity type circular recess, the opening of the heat insulating paper, and the flat surface of the tip end surface of the tip of the hot runner nozzle. In the space facing the gate entrance of
A resin molten layer formed of molten resin from a hot runner nozzle,
The molten resin can be solidified by overlapping with the resin melt layer and exchanging heat with the resin melt layer, and by contacting the inner top surface of the concave portion of the cavity type circular recess and exchanging heat with the cavity type. It is compressed and deformed to a thickness that forms two layers with the resin heat insulating layer.
The opening of the heat insulating paper is
Release of the preform in a state where the resin located in the resin heat insulating layer that exchanges heat with the resin molten layer is blow-molded by the contact with the inner top surface of the concave portion of the cavity type circular recess. It maintains a solidified state in which breakage separation occurs between the resin and the resin located at the gate opening of the cavity gate during molding.
The circular opening of the opening is
The resin located in the resin heat insulating layer that exchanges heat with the resin molten layer comes into contact with the inner top surface of the recess of the cavity-type circular recess, and is wide enough to exchange heat to maintain the solidified state. It is a preform molding apparatus characterized by the above, and provides this preform molding apparatus to solve the above-mentioned problems.

(Invention of claim 2)
The ratio of the circular opening area ratio of the opening of the heat insulating paper to the gate opening of the cavity gate is
The resin located in the resin heat insulating layer that exchanges heat with the resin melt layer is released from the preform in a state where the blow molding is possible by the contact with the inner top surface of the concave portion of the cavity type circular recess. It is preferable that the ratio is a circular opening area ratio that enables heat exchange to maintain a solidified state in which breakage separation occurs with the resin located at the gate opening of the cavity gate at the time of molding.

(Invention of claim 1)
According to the invention of claim 1, the heat insulating paper which is a disk-shaped heat insulating member is a flat surface which is a flat surface of the inner top surface of the recess of the cavity type circular hole-shaped recess and a flat surface which is the tip end surface of the tip portion of the hot runner nozzle. By sandwiching with the surface, the resin melt layer formed of the molten resin from the hot runner nozzle and the resin melt layer are overlapped on the resin melt layer to exchange heat with the resin melt layer, and the cavity is exchanged. The thickness is provided so as to form two layers with a resin heat insulating layer that can be solidified by heat exchange with the cavity mold in contact with the inner top surface of the concave portion of the mold.

In this way, two layers, a resin melt layer and a resin heat insulating layer that overlaps the resin melt layer, are formed in the perforated portion of the heat insulating paper, so that the preform is in a state where blow molding is possible. At the time of mold release, breakage occurs between the resin of the gate portion of the preform and the resin of the resin heat insulating layer, and stringing does not occur. Therefore, even if the preform is pulled up from the cavity mold at the timing when blow molding can be performed, it is possible to perform an appropriate mold release without stringing.

Further, since the resin molten layer into which the molten resin flows from the hot runner nozzle is provided as the lower layer of the resin heat insulating layer, the hot runner can be easily operated by adjusting the thickness of the heat insulating paper. By feeding the molten resin from the nozzle side, it is possible to break through the resin heat insulating layer without resistance and secure a state in which the molten resin can be fed to the injection molding mold side.

Further, when the opening is a small hole, whitening is likely to occur in the gate portion of the preform, but in the present invention, the circular opening of the opening is located in the resin heat insulating layer that exchanges heat with the resin molten layer. Since the resin to be used is wide enough to allow heat exchange to come into contact with the inner top surface of the cavity-shaped circular hole-shaped recess and maintain the solidified state, the size of the opening is widened to allow the preform. Whitening of the gate portion can be prevented.

(Invention of claim 2)
According to the invention of claim 2, it is sufficient to provide the holes of the heat insulating paper from the ratio based on the circular opening area of the gate opening of the cavity type cavity gate, which is excellent in that the heat insulating paper can be easily produced. It is effective.

It is explanatory drawing which shows the tip side of the hot runner nozzle in the expanded state in embodiment of the preform molding apparatus which concerns on this invention. It is explanatory drawing which shows the conventional preform molding apparatus. Similarly, it is explanatory drawing which shows the tip side of the hot runner nozzle in the expanded state in the embodiment of the conventional preform molding apparatus.

Next, the present invention will be described in detail based on the embodiment shown in FIG. The parts whose configurations overlap with those of the conventional examples shown in FIGS. 2 and 3 are designated by the same reference numerals, and the description thereof will be omitted.

The preform molding apparatus 1 of the present invention includes a hot runner apparatus 2 and an injection molding die 4 configured on the upper portion of the hot runner apparatus 2. As described above, in the hot runner device 2, a plurality of hot runner nozzles 3 are erected according to the number of molds.

Further, in the injection molding die 4, a preform molding space is formed in a portion above the hot runner nozzle 3, and the tip 7 of the hot runner nozzle 3 is directed downward into the circular recess 6. It has a cavity mold 5 reached by a tapered cavity gate 8. As described above, the injection molding mold 4 forms the cavity mold 5, the core mold that can be vertically arranged inside the cavity mold 5, and the shape of the outer peripheral surface of the mouth of the preform. It is composed of a lip mold that also serves to convey a hollow molded body that has been conveyed and blow-molded.

Then, the injection molding die 4 molds the resin injected from the hot runner nozzle 3 side through the cavity gate 8 into a preform, and after the injection molding, the preform is released in a state where blow molding is possible. It is something that is. The injection molding mold 4 is composed of a cavity mold 5, a core mold, and a lip mold. In order to clearly explain the points of the present invention, in FIG. 1, the lower portion of the injection molding mold 4 is shown. Shown. Further, in FIGS. 2 and 3, the lower portion of the injection molding mold 4 is shown.

(Insulated paper)
A disk-shaped heat insulating paper 12 is fitted on the inner top surface 10 side of the concave portion 6 of the circular hole-shaped concave portion 6 of the cavity type 5. Then, the heat insulating paper 12 is sandwiched between the concave inner top surface 10 on the cavity type 5 side and the tip end surface 11 on the hot runner nozzle 3 side.

An opening 15 is punched out in the center of the heat insulating paper 12, and the opening 15 is a circular opening concentric with the center of the heat insulating paper 15. The center of the opening 15 is located at a position corresponding to the gate opening 14 of the cavity gate 8, and is opened with a larger diameter than the gate opening 14.

The top surface 10 of the recess on the cavity type 5 side is a flat surface, and the end surface 11 of the tip portion on the hot runner nozzle 3 side is also a flat surface. The heat insulating paper 12 is not simply sandwiched between the flat surface of the concave inner top surface 10 on the cavity type 5 side and the flat surface of the tip end surface 11 on the hot runner nozzle 3 side, but the two flat surfaces. It is compressed and deformed so that the thickness of the heat insulating paper 12 is reduced by being sandwiched between the two.

(Adjusting the thickness of heat insulating paper by compression deformation)
Regarding the degree of compression deformation in which the thickness of the heat insulating paper 12 becomes smaller, for example, when the thickness when not receiving compression pressure in the thickness direction is 100, the thickness of the heat insulating paper 12 after compression deformation is described above. It is good to make it about 92 with respect to 100. In addition, it is a condition that two layers made of resin described later are formed in the opening 15 at the time of injection molding.

The heat insulating paper 12 is not limited to one sheet, and a plurality of sheets can be stacked and used as needed. As a specific example, two sheets of heat insulating paper 12 having a hole 15 having a diameter of 8 mm and a thickness of 0.76 mm are prepared and fitted into the circular recess 6 in a superposed state. Then, the two sheets of the heat insulating paper 12 which is overlapped with each other are compressed and deformed so as to have a thickness of 1.40 mm by sandwiching the two flat surfaces.

(Space in the center of the heat insulating paper)
As described above, the heat insulating paper 12 is sandwiched between the circular recess 6 of the cavity type 5 and the tip portion 7 of the hot runner nozzle 3. In the central portion of the heat insulating paper 12, the inner top surface of the recess, which is the flat surface of the circular recess 6 of the cavity type 5, the inner peripheral surface of the opening 15 of the heat insulating paper 12, and the tip of the hot runner nozzle 3 A space 16 is formed which is surrounded by the tip end surface 11 which is a flat surface of 7.

The nozzle port 17 of the hot runner nozzle 3 faces the space 16 from below, and the gate port 14 of the cavity gate 8 faces from above. Then, the injection gossip blow molding machine equipped with the preform molding device 1 operates, and the molten resin is supplied from the injection device side to the injection molding mold 4 via the hot runner device 2, so that the space 16 is always occupied. It will be filled with resin.

The thickness of the heat insulating paper 12 can be changed by applying pressure from above and below as described above. Then, the state of the resin filling the space 16 changes depending on the thickness of the heat insulating paper 12. That is, the state of the resin inside the space 16 is different depending on whether the upper and lower dimensions of the space 16 are increased or decreased.

Then, in the present embodiment, the heat insulating paper 12 is sandwiched between the inner top surface 10 of the circular hole-shaped recess 6 of the cavity type 5 and the tip end surface 11 of the tip 7 of the hot runner nozzle 3. The space 16 of the opening 15 of the heat insulating paper 12 is filled with a molten resin that passes through a resin path from the nozzle opening 17 to the gate opening 14 when the preform molding apparatus 1 is in operation, and the molten resin is used to fill the resin molten layer. It is compression-deformed to a thickness forming two layers of 18 and the resin heat insulating layer 19.

(Resin melt layer)
The resin molten layer 18 is a layer formed of the molten resin from the hot runner nozzle 3, and is a portion in which the molten resin at a high temperature can flow.

(Resin insulation layer)
Further, the resin heat insulating layer 19 is overlapped on the resin molten layer 18 to exchange heat with the molten resin of the resin molten layer 18, and is in contact with the concave inner top surface 10 of the circular recess 6 of the cavity type 5. This is a layer in which the molten resin can be solidified by heat exchange with the cavity type 5.

In addition, in the space 16 when the upper and lower dimensions of the space 16 are set so that the thickness of the heat insulating paper 12 after compression deformation is further smaller than about 92 with respect to the thickness 100 at the time of non-compression, the space 16 is It is likely to be filled with molten resin. On the other hand, when the upper and lower dimensions of the space 16 are made to be significantly larger than the above value of 1.40 mm (for example, when the upper and lower dimensions of the space 16 are increased by stacking three sheets of heat insulating paper 12). The thickness of the solidified resin layer formed on the inner top surface 10 side of the concave recess 6 of the cavity type 5 increases, and the resistance when the molten resin is sent to the cavity type 5 side increases.

(Size of circular opening of opening)
As described above, the preform molding apparatus 1 is designed to release the preform in a state where it can be blow molded. The opening 15 of the heat insulating paper 12 is devised so that when the preform is released, a resin that is stretched into a thin thread is not generated between the resin at the gate and the resin located at the opening 15. However, it is implemented with a simple configuration.

That is, the opening 15 of the heat insulating paper 12 is made of the resin located in the resin heat insulating layer 19 that constantly exchanges heat with the resin molten layer 18 and is formed on the inner top surface 10 of the concave portion 6 of the circular hole-shaped concave portion 6 of the cavity type 5. By contact with the resin, the preform is maintained in a solidified state in which break separation occurs from the resin located at the gate port 14 of the cavity gate 8 when the preform is released in a state where blow molding is possible.

Then, in the circular opening of the opening 15, the resin located in the resin heat insulating layer 19 that exchanges heat with the resin melting layer 18 comes into contact with the concave inner top surface 10 on the cavity type 5 side and is maintained in the solidified state under the above conditions. It is provided in a size that allows heat exchange.

Further, both the gate opening 14 and the opening 15 are circular openings and are arranged so as to be concentric, and the ratio of the circular opening area ratio of the opening 15 of the heat insulating paper 12 to the gate opening 14 of the cavity gate 8 is as follows. I am trying to do it. That is, the resin located in the resin heat insulating layer 19 that exchanges heat with the resin molten layer 18 with respect to the circular opening area ratio is brought into contact with the concave inner top surface 10 of the circular hole-shaped concave portion 6 of the cavity type 5. Circular opening area ratio that enables heat exchange to maintain a solidified state in which break separation occurs with the resin located at the gate port 14 of the cavity gate 8 when the preform is released in a state where blow molding is possible. It is said.

As a specific example, the cavity type 5 having a gate opening 14 having a diameter of 2 mm, and the resin heat insulating layer that exchanges heat with the concave inner top surface 10 on the cavity type 5 side. In order to preferably obtain 19, the diameter of the circular opening of the opening 15 is preferably about 8 mm, and the ratio of the circular opening area of the gate opening 14 to the circular opening area of the opening 15 is about. It is good to set it to 3:50.

By setting the circular area ratio, the resin heat insulating layer 19 that is in contact with the cavity mold 5 and exchanges heat is maintained in a solidified state similar to the resin at the gate portion of the preform that is released at the timing when blow molding is possible. Will be done. Then, when the preform is released from the mold, break separation occurs between the resin at the gate portion of the preform and the resin maintained in the solidified state of the resin heat insulating layer 19. Therefore, stringing does not occur at the gate portion of the preform that has been released at the timing when blow molding is possible.

Assuming that the diameter of the circular opening of the opening 15 of the heat insulating paper 12 whose thickness has been compressed and deformed as described above is about 4 mm, and the ratio of the circular opening area of the gate opening 14 to the opening 15 is about 3:13. , It is not preferable because the possibility of stringing occurs.

The above-mentioned heat insulating paper is a name that refers to a paper-like sheet having high heat insulating properties, and does not consist of 100% pulp. The heat insulating paper 12 used in the above embodiment is a heat insulating paper made of meta-aramid fiber, and Nomex paper manufactured by DuPont (Nomex registered trademark) was used.

1 ... Preform molding device 2 ... Hot runner device 3 ... Hot runner nozzle 4 ... Injection molding type 5 ... Cavity type 6 ... Cavity type circular recess 7 ... Hot runner nozzle tip 8 ... Cavity gate 10 ... Inside the recess Top surface 11 ... Tip end surface 12 ... Insulation paper 14 ... Gate opening 15 ... Opening 16 ... Space 17 ... Nozzle opening 18 ... Resin molten layer 19 ... Resin insulation layer

Claims (2)

It has a hot runner device in which a plurality of hot runner nozzles are erected, and a cavity type in which a cavity gate tapered downward reaches a circular concave portion into which the tip of the hot runner nozzle enters. In a preform molding apparatus including an injection molding mold that molds a resin injected from the hot runner nozzle side through a cavity gate into a preform and then releases the preform in a state where blow molding is possible after the injection molding.
The inner top surface of the cavity-shaped circular recess is a flat surface, and the end surface of the tip of the hot runner nozzle is a flat surface.
A disk-shaped heat insulating paper having a hole in the center is fitted into the cavity-shaped circular hole-shaped recess, and the gate opening of the cavity gate is located at the center of the hole in the heat insulating paper.
The heat insulating paper is sandwiched between the flat surface of the inner top surface of the cavity-shaped circular recess and the flat surface of the tip end surface of the tip of the hot runner nozzle so as to be compressible and deformable.
The heat insulating paper sandwiched between the cavity-type circular recess and the tip of the hot runner nozzle that has entered the circular recess is
The nozzle port of the hot runner nozzle and the cavity gate are surrounded by the flat surface of the inner top surface of the cavity type circular recess, the opening of the heat insulating paper, and the flat surface of the tip end surface of the tip of the hot runner nozzle. In the space facing the gate entrance of
A resin molten layer formed of molten resin from a hot runner nozzle,
The molten resin can be solidified by overlapping with the resin melt layer and exchanging heat with the resin melt layer, and by contacting the inner top surface of the concave portion of the cavity type circular recess and exchanging heat with the cavity type. It is compressed and deformed to a thickness that forms two layers with the resin heat insulating layer.
The opening of the heat insulating paper is
Release of the preform in a state where the resin located in the resin heat insulating layer that exchanges heat with the resin molten layer is blow-molded by the contact with the inner top surface of the concave portion of the cavity type circular recess. It maintains a solidified state in which breakage separation occurs between the resin and the resin located at the gate opening of the cavity gate during molding.
The circular opening of the opening is
The resin located in the resin heat insulating layer that exchanges heat with the resin molten layer comes into contact with the inner top surface of the concave portion of the cavity type circular recess, and is wide enough to exchange heat to maintain the solidified state. A preform molding device characterized by being The ratio of the circular opening area ratio of the opening of the heat insulating paper to the gate opening of the cavity gate is
The resin located in the resin heat insulating layer that exchanges heat with the resin molten layer is released from the preform in a state where the blow molding is possible by the contact with the inner top surface of the concave portion of the cavity type circular recess. The preform molding apparatus according to claim 1, which is a circular opening area ratio that enables heat exchange to maintain a solidified state in which breakage separation occurs between the resin and the resin located at the gate opening of the cavity gate at the time of molding.

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