WO2019225062A1

WO2019225062A1 - Preform molding device

Info

Publication number: WO2019225062A1
Application number: PCT/JP2019/003323
Authority: WO
Inventors: 町田　敏宏
Original assignee: 株式会社青木固研究所
Priority date: 2018-05-24
Filing date: 2019-01-31
Publication date: 2019-11-28
Also published as: TW202003200A; JP2021137965A

Abstract

The purpose of the present invention is to manufacture a hollow molded body in which whitening does not occur in a gate part and which is free from stringiness in such a manner that a preform capable of being blow-molded is properly divided between a resin portion of the gate part and a resin portion on a heat insulation sheet side of the preform to allow mold release by a preform molding device in which a disc-shaped heat insulation sheet having a simple shape is held between a circular-hole-shaped concave part on a cavity mold side and a tip end of a hot runner nozzle that is inserted into the circular-hole-shaped concave part. The thickness of a heat insulation sheet 13 is set at a thickness at which a resin melting layer 20 and a resin heat insulation layer 21 are formed in an opening 16 of the heat insulation sheet 13, and the circular opening of the opening 16 is set at a width at which a resin in the resin heat insulation layer 21 that performs heat exchange with the resin melting layer 20 is allowed to come in contact with an inter-concave part top surface 10 of a circular-hole-shaped concave part 6 of a cavity mold 5 and perform heat exchange to maintain a solidified state.

Description

Preform molding equipment

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

In an injection stretch blow molding machine, a blow molding die is used to stretch and blow an injection molding part in which a resin is injected from an injection device and injection molding a preform and a preform released from the injection mold of the injection molding part. A stretch blow molding section that performs molding to obtain a hollow molded body, and a take-out section that takes out the hollow molded body from the blow mold of the stretch blow molding section 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 fed from the injection device into a plurality of runners, and a hot runner device that is located above the hot runner device, a preform corresponding to each runner is provided. A preform molding apparatus is composed of an injection mold composed of a mold for injection molding.

The injection mold in this preform molding apparatus is a lip mold that forms the mouth outer peripheral surface shape of the preform and also serves to carry the injection molded preform, and the outer peripheral surface shape and bottom of the preform body A cavity mold that forms the outer surface shape and a core mold that forms the inner surface shape from the mouth to the bottom of the preform are combined.

As shown in FIG. 3, the hot runner device 2 of the preform molding apparatus 1 has a hot runner nozzle 3 standing upright, and although not shown, the hot runner nozzles 3 are arranged in a state where a plurality of the hot runner nozzles 3 are upright. ing. A cavity mold 5 of an injection 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 inserted into a circular recess 6 formed in the lower surface of the cavity mold 5. Part 7 has entered. A cavity gate 8 that tapers downward reaches the center of the circular recess 6.

A heat insulating member 9 having an opening 16 (see FIG. 4) at the center is sandwiched between the circular recess 6 on the lower surface of the cavity mold 5 and the tip 7 of the hot runner nozzle 3. The heat insulating member 9 is used for the purpose of making it difficult for heat propagation to occur between the high temperature hot runner nozzle 3 and the cavity mold 5, and also serves as a sealing member for preventing resin leakage.

In other words, in the above-described injection stretch blow molding machine, high temperature molten resin is injected from the injection device into the injection mold through the hot runner device, and the hot runner nozzle portion is also kept at a high temperature in order to maintain the molten state of the resin. 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.

The cooling on the injection mold side does not affect the tip of the hot runner nozzle, and the cooling from the molten resin injected into the injection mold is not impaired by the heat from the hot runner nozzle side. There is a need to. For this purpose, the heat insulating member is sandwiched between the cavity-shaped circular recess and the tip of the hot runner nozzle.

The injection stretch blow molding machine is a molding machine for producing a hollow molded body by a hot parison type molding method in which a preform released from an injection mold as described above is stretch blow molded with a blow mold. It is. Therefore, the preform is released from the injection mold at a timing at which the mold does not lose its shape even when it is released and is ready for blow molding.

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, a gap between the concave portion on the lower surface of the cavity mold and the tip of the hot runner nozzle is used. Shows a technique in which a disk-shaped heat insulating member is sandwiched.

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

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

Japanese Patent Laying-Open No. 2004-025812 (FIG. 4) Japanese Unexamined Patent Publication No. 2000-351151 (FIG. 2) JP 2002-316342 A

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

The heat insulating member shown in Patent Document 1 has a disk shape, and if it is compared with the heat insulating members shown in

Patent Documents

2 and 3, the shape is simple and can be made with high yield. It is a heat insulating member that can be made.

In the preform molding apparatus 1 shown in FIG. 3 and FIG. 4, the concave top surface 10 of the circular recess 6 of the cavity mold 5 is a flat surface, and the hot runner nozzle 3 of the hot runner apparatus 2 The distal end portion end surface 11 of the distal end portion 7 is a flat surface, and the entire end portion end surface 11 serves as a heat insulating member contact surface 12.

And in the said preform shaping | molding apparatus 1 as shown in FIG. 4, between the top surface 10 of a recessed part by the side of the cavity type | mold 5, and the said heat insulation member contact surface 12 by the side of the hot runner nozzle 3, it is a disk-shaped heat insulation member. 9 was sandwiched in a superposed state with the heat insulating paper 13 being the lower side and the stainless steel heat insulating plate 14 being the upper side.

Of course, the heat insulating paper 13 and the heat insulating plate 14 used in the above combination have an opening 16 corresponding to the gate port 15 (diameter of about 2 mm) at the lower end of the cavity gate 8. The diameter of the opening 16 of the heat insulating plate 14 is, for example, the same as or smaller than the diameter of the gate opening 15, and the diameter of the opening 16 of the heat insulating paper 13 is about 1 smaller than the diameter of the gate opening 15, for example. About 4 mm. The concave inner surface 10 on the cavity mold 5 side and the heat insulating member contact surface 12 on the hot runner nozzle 3 side so that the thickness t of the heat insulating paper 13 and the heat insulating plate 14 overlapped is about 0.4 mm. It is compressed by two flat surfaces.

The reason why the heat insulating member 9 is configured by superposing the heat insulating paper 13 and the heat insulating plate 14 is that when the heat insulating paper 13 is used alone, the opening 16 of the heat insulating paper 13 is caused by repeated passage of the molten resin. This is because the diameter of the heat insulating paper 14 is gradually increased and the metal heat insulating plate 14 is overlapped with the heat insulating paper 13 to prevent the opening 16 of the heat insulating paper 13 from spreading.

In this way, in the preform molding apparatus in which the preform is injection-molded and released so that the preform can be transferred to the stretch blow mold without taking time, the heat insulating member 9 is formed in a disk shape. It was.

However, in the preform molding apparatus 1, when the preform is released at a timing at which blow molding is possible, the resin of the gate portion of the preform and the resin in the opening 16 of the heat insulating member 9 are appropriately set. There was a case where stringing occurred at the gate portion without separation.

Under the condition that the mold can be released in a state where blow molding is possible, as a measure for preventing the above-described stringing itself from occurring, the opening 16 of the heat insulating member 9 is made to have a small diameter. When the diameter of 16 is reduced, it is difficult for molten resin to be fed from the hot runner nozzle to the injection mold. Moreover, the malfunction of whitening the gate part of a preform arises.

Therefore, in view of the above circumstances, the present invention sandwiches a disk-shaped heat-insulating paper having a simple shape between the circular hole-shaped concave portion on the cavity mold side and the tip of the hot runner nozzle inserted into the circular hole-shaped concave portion. In a preform molding apparatus, a preform that can be blow-molded can be released by properly dividing the resin part of the gate part of the preform and the resin part located on the heat insulating paper side. The object is to produce a hollow molded body in which no whitening occurs in the gate portion and no stringing occurs.

(Invention of Claim 1)
The present invention has been made in consideration of the above-mentioned problems, and is tapered downward in a hot runner device in which a plurality of hot runner nozzles are erected and a circular hole-like concave portion into which the tip of the hot runner nozzle enters. The cavity mold has reached the cavity gate, the resin injected from the hot runner nozzle side through the cavity gate is molded into a preform, and the preform is released in a state where blow molding is possible after the injection molding. In a preform molding apparatus comprising an injection mold for molding,
The top surface in the concave portion of the cavity-shaped circular concave portion is a flat surface, and the heat insulating member contact surface at the tip of the hot runner nozzle is a flat surface,
A disk-shaped heat insulating paper having an opening at the center is fitted into the cavity-shaped circular hole-shaped concave portion, and the gate port of the cavity gate is located at the center of the opening of the heat-insulating paper,
The heat insulating paper is sandwiched between the flat surface of the top surface of the concave portion of the cavity-shaped circular hole-shaped concave portion and the heat insulating member contact surface of the front end portion of the hot runner nozzle so as to be compressively deformable,
The heat insulating paper sandwiched between the cavity-shaped circular recess and the tip of the hot runner nozzle that has entered the circular recess,
Surrounded by the flat surface of the top surface of the cavity-shaped circular hole-shaped recess, the opening of the heat insulating paper, and the tip of the hot runner nozzle, the nozzle port of the hot runner nozzle and the gate port of the cavity gate face each other. In the space
A resin melt layer formed of a molten resin from a hot runner nozzle,
The resin melt layer overlaps with the resin melt layer and heat exchange with the resin melt layer is possible. The melt resin can be solidified by contact with the top surface of the cavity mold circular recess and heat exchange with the cavity mold. It is compressed and deformed to a thickness that forms two layers with the resin heat insulation layer,
The hole in the heat insulating paper is
The resin positioned in the resin heat insulating layer that exchanges heat with the resin melt layer is separated from the preform in a state in which the blow molding is enabled by the contact with the top surface of the cavity-shaped circular recess. Maintaining a solidified state in which fracture separation occurs between the resin located at the gate opening of the cavity gate at the time of molding,
The circular opening of the opening is
The resin positioned in the resin heat insulating layer that exchanges heat with the resin melt layer is in contact with the top surface of the cavity of the cavity-shaped circular recess so that heat exchange can be performed to maintain the solidified state. The preform molding apparatus is characterized by providing the preform molding apparatus to solve the above-mentioned problems.

(Invention of Claim 2)
The ratio of the circular opening area of the opening of the heat insulating paper to the gate opening of the cavity gate is:
The resin positioned in the resin heat insulating layer that exchanges heat with the resin melt layer is separated from the preform in a state in which the blow molding is enabled by the contact with the top surface of the cavity-shaped circular recess. It is favorable that the ratio of the circular opening area is such that heat exchange can be performed while maintaining a solidified state in which fracture separation occurs between the resin located at the gate port of the cavity gate during molding.

(Effect of the invention of claim 1)
According to invention of Claim 1, the heat insulation paper which is a disk-shaped heat insulation member is the heat insulation member which is the flat surface of the top surface of a recessed part of a cavity type | mold circular hole-shaped recessed part, and the flat surface of the front-end | tip part of a hot runner nozzle. Resin melting formed by the molten resin from the hot runner nozzle in the space surrounded by the top surface of the concave portion of the circular hole-shaped concave portion, the opening of the heat insulating paper and the tip of the hot runner nozzle by sandwiching with the contact surface Heat exchange between the layer and the resin melt layer overlaps with the resin melt layer, and can be solidified by contact with the top surface of the cavity-shaped concave recess and heat exchange with the cavity mold It is provided in a thickness so that two layers with a resin heat insulating layer are formed.

Thus, in the space surrounded by the top surface of the concave portion of the circular concave portion, the opening of the heat insulating paper, and the tip of the hot runner nozzle, the resin molten layer and the resin heat insulating layer overlapping the resin molten layer are formed. Since two layers are formed, at the time of release of the preform in a state where blow molding is possible, a break occurs between the resin of the gate part of the preform and the resin of the resin heat insulating layer, Stringing does not occur. Therefore, even if the preform is pulled up from the cavity mold at a timing at which blow molding can be performed, there is an effect that an appropriate mold release without stringing can be performed.

In addition, since the resin melt layer in which the molten resin flows from the hot runner nozzle is provided as a lower layer of the resin heat insulating layer, the hot runner can be easily operated by adjusting the thickness of the heat insulating paper. There is an effect that it is possible to secure a state in which the molten resin can be fed to the injection mold side by breaking through the resin heat insulation layer without resistance by feeding the molten resin from the nozzle side.

Further, when the opening was a small hole, whitening was likely to occur in the gate portion of the preform. However, in the present invention, the opening is a circular opening, and this circular opening is the thermal contact with the resin melt layer. Since the resin located in the resin heat insulating layer to be exchanged is in contact with the top surface of the cavity-shaped circular recess, the heat exchange to maintain the solidified state is possible. The width can be increased to prevent whitening of the gate portion of the preform.

(Effect of the invention of claim 2)
According to the second aspect of the present invention, it is only necessary to provide the opening of the heat insulating paper from the ratio based on the circular opening area of the gate opening of the cavity type cavity gate, and it is excellent in that the heat insulating paper can be easily manufactured. There is an effect.

It is explanatory drawing shown in the state which expanded the front-end | tip part side of the hot runner nozzle in embodiment of the preform shaping | molding apparatus which concerns on this invention. It is explanatory drawing which shows the example of another implementation. It is explanatory drawing which shows the conventional preform shaping | molding apparatus. Similarly, it is explanatory drawing shown in the state which expanded the front-end | tip part side of the hot runner nozzle in embodiment of the conventional preform shaping | molding apparatus.

Next, the present invention will be described in detail based on the embodiment shown in FIGS. 3 and 4 are denoted by the same reference numerals, and the description thereof is omitted.

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

In addition, in the injection mold 4, a preform molding space is formed in a portion above the hot runner nozzle 3, and directed downward into the circular recess 6 into which the tip 7 of the hot runner nozzle 3 enters. It has a cavity mold 5 which is reached by a tapered gate 8 which is tapered. As described above, the injection mold 4 forms the cavity mold 5, a core mold that can be arranged inside the cavity mold 5 up and down, and the shape of the outer peripheral surface of the mouth of the preform. It is comprised from the lip type | mold which also serves as the role which conveys the hollow molded object conveyed and blow molded.

The injection mold 4 molds the resin injected through the cavity gate 8 from the hot runner nozzle 3 side into a preform, and releases the preform in a state where blow molding is possible after the injection molding. It is what. The injection 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, the lower part of the injection mold 4 is shown in FIGS. The part is illustrated. 3 and 4, the lower part of the injection mold 4 is shown.

(Insulated paper)
A disc-shaped heat insulating paper 13 is fitted into the concave inner surface 10 side of the circular hole-shaped concave portion 6 of the cavity mold 5. The heat insulating paper 13 is sandwiched between the top surface 10 of the concave portion on the cavity mold 5 side and the heat insulating member contact surface 12 formed on the tip end surface 11 of the tip 7 of the hot runner nozzle 3.

An opening 16 is punched and formed in the center of the heat insulating paper 13, and this opening 16 is a circular opening (circular opening) concentric with the center of the heat insulating paper 13 itself. The center of the opening 16 is positioned corresponding to the gate port 15 of the cavity gate 8 and is opened with a larger diameter than the gate port 15.

The top surface 10 in the recess on the cavity mold 5 side is a flat surface. Moreover, the front end portion end surface 11 on the hot runner nozzle 3 side is also a flat surface, and the heat insulating member contact surface 12 formed on the front end portion end surface 11 is also a flat surface. The heat insulating paper 13 is not only positioned between the flat surface of the concave top surface 10 on the cavity mold 5 side and the flat surface of the heat insulating member contact surface 12 on the hot runner nozzle 3 side. The heat insulating paper 13 is compressed and deformed so that the thickness of the heat insulating paper 13 is reduced by being sandwiched between the flat surfaces.

(Adjustment of insulation paper thickness by compression deformation)
With respect to the degree of compression deformation in which the thickness of the heat insulating paper 13 is reduced, for example, when the thickness when the pressure of compression is not applied in the thickness direction is 100, the thickness of the heat insulating paper 13 after the compression deformation is It is preferable that the ratio is about 92 with respect to 100. It is to be noted that two layers of resin, which will be described later, are formed in the opening 16 during injection molding.

It is not limited that the heat insulating paper 13 is a single sheet, and a plurality of sheets can be used by overlapping as necessary. As a specific example, two sheets of heat insulating paper 13 having an opening 16 with a diameter of 8 mm and a thickness of 0.76 mm are prepared and fitted into the circular hole-shaped recess 6 in a superposed state. Then, the heat insulating paper 13 superposed on the two sheets is compressed and deformed so as to have a thickness of 1.40 mm by sandwiching the two flat surfaces.

(space)
As described above, the heat insulating paper 13 is sandwiched between the circular recess 6 of the cavity mold 5 and the tip 7 of the hot runner nozzle 3. The central portion of the heat insulating paper 13 includes a concave inner surface 10 which is a flat surface of the circular concave portion 6 of the cavity mold 5, an inner peripheral surface of the opening 16 of the heat insulating paper 13, and a tip portion of the hot runner nozzle 3. A space 18 is formed that is surrounded by a nozzle port peripheral surface 17 (a portion that becomes a heat insulating member non-contact region in the tip end surface 11) that is a part of the tip end surface 11 that is a flat surface 7. .

In the space 18, a nozzle port 19 of the hot runner nozzle 3 faces from below, and a gate port 15 of the cavity gate 8 faces from above. Then, the injection stretch blow molding machine equipped with the preform molding apparatus 1 is operated and molten resin is supplied from the injection apparatus side to the injection mold 4 through the hot runner apparatus 2, so that the space 18 is always resin. It will be filled with.

As described above, the thickness of the heat insulating paper 13 can be changed by applying pressure from above and below. The state of the resin filled in the space 18 changes depending on the thickness of the heat insulating paper 13. That is, the state of the resin inside the space 18 differs between when the upper and lower dimensions of the space 18 are increased and when the dimension is decreased.

In the present embodiment, the heat insulating paper 13 is formed by filling the space 18 with molten resin passing through a resin path from the nozzle port 19 toward the gate port 15 when the preform molding apparatus 1 is in operation. The space 18 is compressed and deformed to a thickness that forms two layers of the resin melt layer 20 and the resin heat insulation layer 21 in the space 18.

(Resin melt layer)
The resin melt layer 20 is a layer formed of the melt resin from the hot runner nozzle 3 and is a portion where the high temperature melt resin can flow.

(Resin insulation layer)
The resin heat insulation layer 21 is superimposed on the resin melt layer 20 to exchange heat with the molten resin of the resin melt layer 20 and is in contact with the top surface 10 in the recess of the circular recess 6 of the cavity mold 5. Thus, the molten resin can be solidified by heat exchange with the cavity mold 5.

It should be noted that the space 18 has an upper and lower dimension such that the thickness of the heat insulating paper 13 after being compressed and deformed is smaller than about 92 with respect to the thickness 100 at the time of non-compression. It is likely to be filled with molten resin. On the other hand, when the vertical dimension of the space 18 is made to be significantly larger than the value of 1.40 mm (for example, when the vertical dimension of the space 18 is increased by stacking three sheets of heat insulating paper 13 or the like), The thickness of the solidified resin layer formed on the concave inner surface 10 side of the circular hole-like concave portion 6 of the cavity mold 5 is increased, and the resistance when the molten resin is fed to the cavity mold 5 side is increased.

(Size of circular opening of opening)
As described above, the preform molding apparatus 1 is configured to release the preform in a state where blow molding is possible. The opening 16 of the heat insulating paper 13 is devised so that when the preform is released from the resin in the gate portion and the resin positioned in the opening 16, a resin that is stretched into a thin thread is not generated. However, it is implemented with a simple configuration.

That is, the opening 16 of the heat insulating paper 13 is made of resin located in the resin heat insulating layer 21 that constantly performs the heat exchange with the resin melt layer 20, and the top surface 10 in the concave portion of the circular concave portion 6 of the cavity mold 5. The solidified state in which breakage separation occurs between the resin located at the gate port 15 of the cavity gate 8 when the preform in a state where blow molding is possible is brought into contact with the resin.

The circular opening (circular opening) of the opening 16 is such that the resin located in the resin heat insulating layer 21 that exchanges heat with the resin melt layer 20 comes into contact with the top surface 10 in the recess on the cavity mold 5 side. It is provided in a size that allows heat exchange to maintain the solidified condition.

Further, the gate opening 15 and the opening 16 are both circular openings and are arranged so as to be concentric. The ratio of the circular opening area of the opening 16 of the heat insulating paper 13 to the gate opening 15 of the cavity gate 8 is expressed as follows. I am doing so. That is, the resin located in the resin heat insulating layer 21 that performs the heat exchange with the resin melt layer 20 is in contact with the top surface 10 in the concave portion of the circular concave portion 6 of the cavity mold 5. 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 port 15 of the cavity gate 8 when the preform in a state in which blow molding is enabled is released. It is said.

As a specific example, the resin mold heat insulating layer is a cavity mold 5 in which the diameter of the gate port 15 is 2 mm, and heat exchange is performed between the cavity mold 5 side and the top surface 10 in the recess. 21 is preferably about 8 mm, and the ratio of the circular opening area of the gate port 15 to the circular opening area of the opening 16 is about It is good to set it as 3:50.

By setting the circular area ratio, the resin heat insulating layer 21 in contact with the cavity mold 5 and exchanging heat is maintained in a solidified state similar to that of the resin of the gate portion of the preform that is released at a timing at which blow molding is possible. Is done. When the preform is released from the mold, fracture 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 21. For this reason, stringing does not occur at the gate portion of the preform that has been released at the timing when blow molding is possible.

In addition, when the diameter of the circular opening of the opening 16 of the heat insulating paper 13 whose thickness is compressed and deformed as described above is about 4 mm, and the circular opening area ratio between the gate port 15 and the opening 16 is about 3:13. This is not preferable because the possibility of stringing increases.

The above-mentioned heat insulating paper refers to a highly heat-insulating paper sheet, and is not made of 100% pulp. The heat insulating paper 13 used in the above embodiment is a heat insulating paper made from a meta-aramid fiber, and Nomex paper (Nomex registered trademark) manufactured by DuPont was used.

(Other examples)
In the above embodiment, the tip end surface 11 of the tip portion 7 of the hot runner nozzle 3 is a flat surface, and the tip end surface 11 is the peripheral surface of the nozzle port with the nozzle port 19 in the center. 17 and the heat insulating member contact surface 12 located continuously outside the nozzle port peripheral surface 17 are formed. However, in the present invention, the entire tip end surface 11 is a flat surface. It is not limited to.

FIG. 2 shows another example of implementation. In this example, the entire surface of the end face 11 of the tip is not a flat face, and the nozzle port peripheral face 17 is made a paragraph so as to be lower than the height position of the heat insulating member contact face 12. A circular tip recess 22 is formed in the center of the tip end surface 11 with the nozzle port peripheral surface 17 as a bottom surface and the nozzle port 19 being opened at the center thereof.

In the embodiment shown in FIG. 2, the flat surface of the concave top surface 10 on the cavity mold 5 side and the flat surface of the heat insulating member contact surface 12 which is the uppermost surface at the tip 7 of the hot runner nozzle 3 The heat insulating paper 13 is positioned between them. The heat insulating paper 13 is compressed so that the thickness of the heat insulating paper 13 is reduced by being sandwiched between the two upper and lower flat surfaces (the top surface 10 in the recess and the heat insulating member contact surface 12), as in the above-described embodiment. It is deformed.

(Adjustment of insulation paper thickness by compression deformation)
(In the case of the previous implementation example)
In the degree of compression deformation in which the thickness of the heat insulating paper 13 is reduced, as described above, the diameter of the aperture 16 is 8 mm and the thickness is 0.76 mm (when not compressed) as described above. Paper 13 (Nomex paper) is used, and the two heat insulating papers 13 are overlapped and sandwiched, and compressed and deformed to a thickness of 1.40 mm by sandwiching the two flat surfaces. That is, the upper and lower dimensions of the space 18 are 1.40 mm.

In the case of the previous embodiment, the thickness of the heat insulating paper 13 after being compressed and deformed when the thickness of the heat insulating paper 13 (two-layered state) is not subjected to compression pressure in the thickness direction is defined as 100. Is about 92 with respect to 100, so that two layers of resin (resin melt layer 20 and resin heat insulation layer 21) are formed in the opening 16 during injection molding.

(In the case of other implementation examples)
As shown in FIG. 2, another embodiment in which the heat insulating paper 13 is sandwiched between the top and bottom surfaces of the cavity inner surface 10 on the cavity mold 5 side and the heat insulating member contact surface 12 around the circular tip recess 22. In the example, the insulating paper 13 is a single sheet. And in the heat insulation paper 13, the inside surface 10 of a recessed part and a heat insulation member contact surface are used using the thing (Nomex paper) whose diameter of the opening 16 is 5 mm and thickness is 0.5 mm (at the time of non-compression). It is preferable to make the thickness 0.3 mm by sandwiching with 12.

(space)
The embodiment shown in FIG. 2 is an example in which a single heat insulating paper 13 is compressed and deformed to have a thickness of 0.3 mm as described above. A circular tip recess 22 is formed.

The space 18 in this example is surrounded by the concave top surface 10 of the circular recess 6 of the cavity mold 5, the inner peripheral surface of the opening 16 of the heat insulating paper 13, and the inner surface of the tip recess 22. Part. Further, the depth of the tip recess 22 is preferably 1.6 mm, the depth of the tip recess 22 (1.6 mm), and the thickness (0.3 mm) of the heat-insulated paper 13 compressed and deformed. Therefore, it is preferable that the vertical dimension of the space 18 is 1.9 mm.

Also in the space 18, the nozzle port 19 of the hot runner nozzle 3 faces from below, and the gate port 15 of the cavity gate 8 faces from above. The injection stretch blow molding machine is operated, and the molten resin is supplied from the injection device side to the injection mold 4 through the hot runner device 2, so that the space 18 is always filled with the resin.

The hot runner nozzle 3 has the tip recess portion 22 of the tip portion 7 thereof, and the compressive deformation of the heat insulating paper 13 by the concave top surface 10 and the heat insulating member contact surface 12 on the cavity mold 5 side is also the same as the above embodiment. Similarly, when the preform molding apparatus 1 is in operation, the molten resin passing through the resin path from the nozzle port 19 to the gate port 15 fills the space 18, and the molten resin fills the space 18 with the molten resin 20 and the resin heat insulating layer. 21 to form a two-layer thickness.

(Size of circular opening of opening)
In the embodiment shown in FIG. 2 as well, the opening 16 of the heat insulating paper 13 is made of resin located in the resin heat insulating layer 21 that always performs heat exchange with the resin molten layer 20, and the top surface 10 in the recess on the cavity mold 5 side. In this contact, when the preform in a state in which blow molding is enabled is released, it is maintained in a solidified state in which fracture separation occurs between the resin located at the gate port 15 of the cavity gate 8.

The circular opening of the opening 16 is also wide enough to allow heat exchange in which the resin located in the resin heat insulation layer 21 is in contact with the top surface 10 of the concave portion on the cavity mold 5 side and is maintained in a solidified state that does not cause stringing. That's it.

Furthermore, the gate opening 15 and the opening 16 are both circular openings and are arranged so as to be concentric. The ratio of the circular opening area of the opening 16 of the heat insulating paper 13 to the gate opening 15 is the same as that of the resin melt layer 20. The resin located in the resin heat insulating layer 21 for heat exchange is in contact with the top surface 10 of the recess on the cavity mold 5 side, and when the preform is released from the preform in a state where blow molding is possible, the gate port 15 of the cavity gate 8 This is also the same as the above example in that the ratio of the circular opening area is such that heat exchange is possible to maintain a solidified state in which breakage separation occurs between the resin and the resin located at the position.

DESCRIPTION OF SYMBOLS 1 ... Preform molding apparatus 2 ... Hot runner apparatus 3 ... Hot runner nozzle 4 ... Injection mold 5 ... Cavity mold 6 ... Cavity mold circular recessed part 7 ... Hot runner nozzle tip part 8 ... Cavity gate 10 ... In the recessed part Top surface 11 ... End surface 12 of the tip part 12 ... Heat insulation member contact surface 13 ... Heat insulation paper 14 ... Heat insulation plate 15 ... Gate port 16 ... Opening 17 ... Nozzle port peripheral surface 18 ... Space 19 ... Nozzle port 20 ... Resin melt layer 21 ... Resin Heat insulation layer 22 ... Columnar tip recess

Claims

A hot runner device in which a plurality of hot runner nozzles are erected, and a cavity mold in which a cavity gate tapered downward is reached in a circular hole-like concave portion into which the tip of the hot runner nozzle enters. In a preform molding apparatus including an injection mold for molding a resin injected from a hot runner nozzle side through a cavity gate into a preform, and releasing the preform in a state where blow molding is possible after the injection molding,
The top surface in the concave portion of the cavity-shaped circular concave portion is a flat surface, and the heat insulating member contact surface at the tip of the hot runner nozzle is a flat surface,
A disk-shaped heat insulating paper having an opening at the center is fitted into the cavity-shaped circular hole-shaped concave portion, and the gate port of the cavity gate is located at the center of the opening of the heat-insulating paper,
The heat insulating paper is sandwiched between the flat surface of the top surface of the concave portion of the cavity-shaped circular hole-shaped concave portion and the heat insulating member contact surface of the front end portion of the hot runner nozzle so as to be compressively deformable,
The heat insulating paper sandwiched between the cavity-shaped circular recess and the tip of the hot runner nozzle that has entered the circular recess,
Surrounded by the flat surface of the top surface of the cavity-shaped circular hole-shaped recess, the opening of the heat insulating paper, and the tip of the hot runner nozzle, the nozzle port of the hot runner nozzle and the gate port of the cavity gate face each other. In the space
A resin melt layer formed of a molten resin from a hot runner nozzle,
The resin melt layer overlaps with the resin melt layer and heat exchange with the resin melt layer is possible. The melt resin can be solidified by contact with the top surface of the cavity mold circular recess and heat exchange with the cavity mold. It is compressed and deformed to a thickness that forms two layers with the resin heat insulation layer,
The hole in the heat insulating paper is
The resin positioned in the resin heat insulating layer that exchanges heat with the resin melt layer is separated from the preform in a state in which the blow molding is enabled by the contact with the top surface of the cavity-shaped circular recess. Maintaining a solidified state in which fracture separation occurs between the resin located at the gate opening of the cavity gate at the time of molding,
The circular opening of the opening is
The resin positioned in the resin heat insulating layer that exchanges heat with the resin melt layer is in contact with the top surface of the cavity of the cavity-shaped circular recess so that heat exchange can be performed to maintain the solidified state. A preform molding apparatus.
The ratio of the circular opening area of the opening of the heat insulating paper to the gate opening of the cavity gate is:
The resin positioned in the resin heat insulating layer that exchanges heat with the resin melt layer is separated from the preform in a state in which the blow molding is enabled by the contact with the top surface of the cavity-shaped circular recess. The preform molding apparatus according to claim 1, wherein the ratio of the circular opening area is such that heat exchange is possible to maintain a solidified state in which fracture separation occurs between the resin located at the gate port of the cavity gate at the time of molding.