Temperature adjustment mold, and manufacturing device and manufacturing method for resin container

Abstract

The present invention relates to a temperature adjustment mold for adjusting the temperature of a bottomed cylindrical preform made of resin, the temperature adjustment mold being provided with: a heat absorption rod which is inserted into the preform in a state of having a gap with the inner periphery of the preform, and which cools the preform from the inside in a non-contact manner; and the more than one heat absorption block is detachably mounted on the heat absorption rod in a manner of partially covering the heat absorption rod, and is used for adjusting the radial clearance between the heat absorption rod and the preformed blank. The heat-absorbing block is thermally connected to the heat-absorbing rod when the heat-absorbing rod is installed, and partially cools the preform in a non-contact manner.

Description

Technical Field

[0001] This invention relates to a mold for temperature regulation, an apparatus for manufacturing resin containers, and a method for manufacturing them. Background Technology

[0002] Previously, hot preform blow molding apparatuses were known as one type of equipment for manufacturing resin containers. Hot preform blow molding apparatuses utilize the residual heat from the injection molding of the preform to blow mold the structure of the resin container. Compared to cold preform blow molding apparatuses, they have an advantage in being able to manufacture a variety of resin containers with excellent appearance.

[0003] Typically, the preform immediately after injection molding does not have a suitable temperature distribution for shaping into a container. Therefore, in the hot preform container manufacturing cycle, a preform temperature adjustment process is performed between the injection molding and blow molding processes to suppress temperature deviations (temperature inconsistencies) in the preform or to impart the desired temperature distribution suitable for shaping into a container.

[0004] For example, from the perspective of shortening the manufacturing cycle of resin containers and promoting high-speed molding of containers, it is necessary to minimize the cooling time of the preform within the injection mold during the injection molding process. In order to ensure the quality of the container during such high-speed molding, it becomes more important to properly adjust the temperature distribution of the preform during the temperature conditioning process.

[0005] In this temperature adjustment process, a temperature-regulating mold is sometimes inserted into the inside of the preform to adjust the temperature of the inner circumference of the preform. For example, as in Patent Document 1, it is also proposed that in the temperature adjustment process, a temperature-regulating mold with a circumferentially non-uniform shape is inserted into the inside of the preform to partially cool the preform that is in contact with the mold.

[0006] Existing technical documents Patent documents Patent Document 1: Japanese Patent Publication No. 7-61675 Summary of the Invention

[0007] The technical problem that the invention aims to solve In the temperature conditioning process, when the preform is cooled by contact with the temperature conditioning mold, the temperature of the preform may drop excessively due to heat conduction to the low-temperature mold, sometimes resulting in poor wall thickness distribution of the container. In addition, depending on the material of the preform, problems such as resin sticking (adhesion, adhesion) to the temperature conditioning mold or deformation of the preform may occur during demolding.

[0008] Furthermore, when compressed air is introduced into the inside of the preform to cool it during the temperature adjustment process, it is difficult to generate localized temperature differences in the circumferential and axial directions, making it difficult to eliminate temperature deviations or achieve the desired uneven temperature distribution. Additionally, when using compressed air for cooling, the preform is compressed from the inside and comes into contact with the outer periphery of the mold cavity. Therefore, depending on the material of the preform, there are situations where cooling with compressed air itself is difficult to achieve.

[0009] Therefore, the present invention was made in view of such problems, and its object is to provide a temperature adjusting mold that can cool the preform without contacting the mold and appropriately adjust the temperature distribution on the inner periphery of the preform.

[0010] Technical solutions for solving technical problems One aspect of the present invention is a temperature adjustment mold for adjusting the temperature of a bottomed cylindrical preform made of resin. The temperature adjustment mold includes: a heat-absorbing rod inserted into the interior of the preform with a gap between it and the inner circumference, for cooling the preform from the inside in a non-contact manner; and one or more heat-absorbing blocks detachably mounted to the heat-absorbing rod, partially covering it, for adjusting the radial gap between the heat-absorbing rod and the preform. The heat-absorbing blocks are thermally connected to the heat-absorbing rod during installation, partially cooling the preform in a non-contact manner.

[0011] Invention Effects According to one aspect of the present invention, a temperature-adjusting mold can be provided, which can cool the preform without contacting the mold and appropriately adjust the temperature distribution on the inner periphery of the preform. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating the configuration of the blow molding apparatus of this embodiment.

[0013] Figure 2 This is a longitudinal cross-sectional view showing an example of the configuration of the temperature adjustment unit in this embodiment.

[0014] Figure 3 This is a perspective view showing an example of the configuration of the heat-absorbing rod in this embodiment.

[0015] Figure 4 This diagram shows a state in which heat-absorbing blocks are partially installed in the circumferential direction of the rod body.

[0016] Figure 5 This is a flowchart illustrating the process of manufacturing the container.

[0017] Figure 6 This is a longitudinal cross-sectional view showing a modified example of the temperature adjustment unit in this embodiment. Detailed Implementation

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0019] In the embodiments, for ease of understanding, the structures and elements of the present invention, except for the main parts, are simplified or omitted in the description. Furthermore, in the accompanying drawings, the same reference numerals are used for the same elements. It should be noted that the shapes, dimensions, etc., of the various elements shown in the drawings are schematic representations and do not represent actual shapes, dimensions, etc.

[0020] Figure 1 This diagram schematically illustrates the configuration of the blow molding apparatus 10 of this embodiment, used for the manufacture of resin containers (hereinafter, also simply referred to as containers). The blow molding apparatus 10 is an example of a container manufacturing apparatus that does not blow the preform 1 ( Figure 1 (Not shown in the figure) The hot preform is cooled to room temperature and then blow-molded into a container using the residual heat (internal heat) from the injection molding process (also known as the one-stage process).

[0021] The blow molding apparatus 10 includes an injection molding section 11, a temperature adjustment section 12, a blow molding section 13, a take-out section 14, and a conveying mechanism 16. The injection molding section 11, the temperature adjustment section 12, the blow molding section 13, and the take-out section 14 are arranged at positions that rotate by a given angle (e.g., 90 degrees) around the conveying mechanism 16 each time.

[0022] (Conveying mechanism 16) The conveying mechanism 16 includes a transfer plate (not shown), which is used for conveying... Figure 1 The paper moves in a rotational direction centered on the axis perpendicular to the paper surface. The transfer plate consists of a single disc-shaped flat plate component or multiple generally fan-shaped flat plate components divided according to each forming station. On the transfer plate, at given angles, one or more neck molds 17 are respectively arranged to hold the neck 2 (or the neck of the container) of the preform 1. Figure 1 (Not shown in the image).

[0023] The conveying mechanism 16 has a rotating mechanism (not shown) that moves the transfer plate to convey the preform 1 (or container) with the neck 2 held by the neck mold 17 in the order of injection molding section 11, temperature adjustment section 12, blow molding section 13, and take-out section 14. It should be noted that the conveying mechanism 16 also has a lifting mechanism (a longitudinal mold opening and closing mechanism) and a neck mold opening mechanism, and performs actions related to lifting the transfer plate, closing the mold of the injection molding section 11, and opening the mold (demolding).

[0024] (Injection molding section 11) The injection molding unit 11 includes an injection cavity mold and an injection core mold (not shown in the figure), and is manufactured as described later. Figure 2 The preform 1 is shown. An injection device 15 for supplying resin material, which is the raw material for the preform 1, is connected to the injection molding unit 11.

[0025] In the injection molding section 11, the aforementioned injection cavity mold, injection core mold, and neck mold 17 of the conveying mechanism 16 are closed to form a mold space in the shape of a preform. Furthermore, by injecting molten resin material from the injection device 15 into such a mold space in the shape of a preform, the preform 1 is manufactured using the injection molding section 11.

[0026] Here, the preform 1 has an overall shape that is a bottomed cylindrical shape with one end open and the other end closed. As described later. Figure 2 As shown, the preform 1 has: a neck 2 formed at one end and having an opening; a main body 3 connected to the neck 2 and formed in a cylindrical shape; and a bottom 4 connected to the main body 3 and closing the other end.

[0027] In addition, the materials for the container and preform 1 are thermoplastic synthetic resins, which can be appropriately selected according to the intended use of the container. Specific types of materials include, for example: PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexanediol terephthalate), Tritan (Tritan (registered trademark): a copolyester manufactured by Eastman Chemical Company, a polyester copolymer using cyclobutanediol as a monomer), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPSU (polyphenylsulfone), PS (polystyrene), COP / COC (cyclic olefin polymer), PMMA (polymethyl methacrylate: acrylic acid), PLA (polylactic acid), etc.

[0028] Although not specifically limited, the preform 1 in this embodiment corresponds to, for example, a large container suitable for a water dispenser. Furthermore, the material of the preform 1 in this embodiment can also be polyethylene terephthalate (PET), polycarbonate (PC), Tritan, etc. It should be noted that the capacity of the large container is, for example, 2 liters to 20 liters, preferably 12 liters to 20 liters.

[0029] It should be noted that even after the injection molding section 11 is opened, the neck mold 17 of the conveying mechanism 16 is not opened, but the preform 1 is kept as is and conveyed. The number of preforms 1 formed simultaneously in the injection molding section 11 (i.e., the number of containers that can be formed simultaneously by the blow molding device 10) can be appropriately set.

[0030] (Temperature adjustment unit 12) The temperature adjustment unit 12 homogenizes and removes temperature deviations from the preform 1 conveyed from the injection molding unit 11, and further adjusts the temperature distribution to bring the temperature of the preform 1 to a suitable temperature for final blow molding (e.g., approximately 170°C to 180°C if the material is PC). In addition, the temperature adjustment unit 12 also cools the preform 1 at its high temperature after injection molding.

[0031] Figure 2 This is a longitudinal cross-sectional view showing an example of the configuration of the temperature adjustment unit 12 in this embodiment. The temperature adjustment unit 12 includes: a temperature regulating chamber mold (heating tank mold or temperature regulating tank mold) 21, which can accommodate the preform 1; and a heat-absorbing rod (generally a temperature regulating rod) 22, which is inserted into the interior of the preform 1.

[0032] The temperature-regulating cavity mold 21 is an example of a temperature-regulating mold, and it is a mold having a temperature-regulating space capable of accommodating the preform 1 held by the neck mold 17. The temperature-regulating space is formed as a bottomed cylindrical shape that is open at the top and corresponds to the shape of the preform 1. The inner diameter of the temperature-regulating cavity mold 21 is set to be larger than the outer diameter (or maximum outer diameter) of the preform, and the axial length of the temperature-regulating cavity mold 21 is set to be longer than the length of the preform 1. Thus, the preform 1 can be inserted from the top into the space of the temperature-regulating cavity mold 21, and the preform 1 can be accommodated in a manner that does not contact the inner surface of the temperature-regulating cavity mold 21.

[0033] The temperature-regulating cavity mold 21 is, for example, a heating tank mold in which one or more sections are provided along the axial direction of the preform 1 to heat the preform 1 in a non-contact manner. The temperature-regulating cavity mold 21 is preferably composed of block members stacked in multiple segments (e.g., eight segments) along the axial direction of the preform 1. Each block member is equipped with a heating element such as a belt heater (not shown). The temperature of each block member is maintained at a given temperature by the heating element, enabling non-contact heating of the main body 3 and bottom 4 of the preform 1 contained therein via radiant heat. It should be noted that the temperature of the heating element is appropriately set within the range of 150 to 275°C. For example, when the material of the preform 1 is PC, it is appropriately set between 150 and 200°C; when the material is PET or Tritan, it is appropriately set between 200 and 275°C.

[0034] It should be noted that, without causing adhesion between the outer surface of the preform 1 and the cavity surface, the temperature-regulating cavity mold 21 can also be a temperature-regulating tank type with a flow path for the flow of a temperature-regulating medium (cooling medium) inside. The temperature of the temperature-regulating cavity mold 21 is maintained at a given temperature by the temperature-regulating medium flowing inside the mold. Thus, the temperature-regulating cavity mold 21 can adjust the temperature of the preform 1 it contains by contacting its outer surface. It should be noted that the temperature of the temperature-regulating medium is not particularly limited; for example, when the material of the preform 1 is PC, it can be appropriately set within the range of 100°C to 200°C, preferably 140°C to 180°C. It should also be noted that the temperature-regulating cavity mold 21 can also be constructed by dividing it into multiple layers in the axial direction and stacking multiple block components, with each block component set to a different temperature.

[0035] The heat-absorbing rod 22 is an example of a temperature-adjusting mold, configured to be retractable within the temperature-adjusting section 12 relative to the neck mold 17 that holds the preform 1. Figure 2 The image shows the state in which the heat-absorbing rod 22 descends to the lower side and is inserted into the interior of the neck mold 17.

[0036] Figure 3 This is a perspective view showing an example of the configuration of the heat-absorbing rod 22 according to this embodiment. The heat-absorbing rod 22 has a core (rod base end) 23, a rod body 24, and a heat-absorbing block (metal component for heat absorption) 25.

[0037] The core 23 is located at the base end (upper side) of the heat absorber 22 and has a tapered shape with a diameter that gradually decreases towards the front end. The shape of the front end of the core 23 corresponds to the inner circumferential shape of the neck mold 17, and a rod body 24 is mounted at the front end of the core 23. When the heat absorber 22 descends, the core 23 is inserted into the inner side of the neck mold 17, serving to guide the descending heat absorber 22 while simultaneously positioning the rod body 24 relative to the preform 1.

[0038] The rod body 24 is, for example, a hollow, rod-shaped mold component formed from a mold material with high thermal conductivity such as carbon steel or stainless steel, extending axially from the front end of the core 23 along the preform 1. Figure 2 As shown, the rod body 24 is formed to be smaller than the inner diameter of the preform 1 and shorter than the axial length of the preform 1. Thus, the rod body 24 can be disposed within the preform 1 at intervals relative to the inner circumference of the preform 1.

[0039] The rod body 24 can be configured without an internal flow path for circulating the cooling medium, as long as it can be cooled by releasing heat to the outside while the heat-absorbing rod 22 is rising. It should be noted that, to avoid temperature rise due to heat accumulation in the heat-absorbing rod 22, an internal flow path for circulating the cooling medium may be included. Thus, the temperature of the rod body 24 is maintained at a given temperature by the cooling medium flowing inside the rod body 24, enabling uniform cooling of multiple preforms 1 even when the blow molding apparatus 10 is operated for extended periods.

[0040] The rod body 24 is formed as a prism (e.g., a prismatic or inverted frustum pyramid) with a cross-sectional shape of a regular polygon orthogonal to the axial direction. The regular polygon can be, for example, a square, a regular hexagon, or a regular octagon. Multiple elongated rectangular circumferential portions (planar portions) 24b (the same number as the number of faces of the regular polygon) are continuously provided along the circumferential direction on the outer surface of the rod body 24. A hollow cylindrical through hole is provided on the inner surface of the rod body 24. Figure 3 As an example, the structure of the rod body 24, with a regular hexagonal cross-section, is shown. Figure 3 As shown, the rod body 24 is configured to allow the heat absorber block 25 to be installed and removed from any area of ​​its peripheral surface 24b. It should be noted that bolt holes (heat absorber block connecting parts) 24a are provided on the surface (peripheral surface 24b) of the rod body 24. The heat absorber block 25 is installed on the rod body 24 using bolts (heat absorber block connecting structural members) 26 that can be screwed into the bolt holes 24a of the rod body 24.

[0041] The heat-absorbing block 25 is a mold piece that is detachably installed on any side (peripheral part 24b) of the outer periphery of the rod body 24 and partially covers the outer periphery of the rod body 24. The heat-absorbing block 25 adjusts the radial distance between the preform 1 and the heat-absorbing rod 22 and performs the function of achieving the desired temperature distribution of the preform 1. More specifically, the heat-absorbing block 25 performs the following functions: absorbing heat radiated (emitted) from the inner periphery of the main body 3 of the preform 1 and transferring the heat to the rod body 24, thereby cooling the main body 3.

[0042] The heat absorber block 25 is formed from a mold material with high thermal conductivity, such as carbon steel or stainless steel, similar to the rod body 24, and is in a state of thermal connection with the rod body 24 when installed on it (e.g., the rod body 24 is in contact with the heat absorber block 25). It should be noted that the heat absorber block 25 can be formed from the same material as the rod body 24 or from a different material.

[0043] Each heat-absorbing block 25 has a curved surface facing the outer periphery of the preform 1, mimicking the inner periphery of the preform 1, while its surface facing the inner periphery of the rod body 24 is flat. The heat-absorbing blocks 25 correspond to the cross-sectional shape of the rod body 24 and are constructed as strips with an arc-shaped outer periphery when viewed from above. Thus, each heat-absorbing block 25 can cover 1 / 6 of the circumferential surface area 24b (i.e., 1 / 1 / the number of faces or angles of the regular polygon of the rod body 24) of the inner periphery of the preform 1. For example, if the cross-section of the rod body 24 is a regular hexagon, the heat-absorbing blocks 25 are arc-shaped strips forming a sixth circle, and each heat-absorbing block 25 covers 1 / 6 of the inner periphery of the preform 1.

[0044] Furthermore, the maximum radial thickness of the heat-absorbing block 25 is set to be smaller than the distance from the surface of the rod body 24 to the inner circumference of the preform 1. Therefore, when the heat-absorbing block 25 is installed, a gap is created between the heat-absorbing block 25 and the inner circumference of the preform 1. Thus, when the heat-absorbing block 25 is installed, the heat-absorbing rod 22 can cool the inner circumference of the preform 1 in a non-contact manner.

[0045] In the heat-absorbing rod 22 of this embodiment, the mounting portion of the heat-absorbing block 25 is provided on each surface (peripheral surface 24b) of the columnar body 24, preferably multiple portions, in the axial direction. For example, in Figure 3 In the heat-absorbing rod 22, the mounting portions of the heat-absorbing blocks 25 are provided at seven locations on each peripheral surface 24b. Therefore, the heat-absorbing blocks 25 can be mounted on any mounting portion arranged circumferentially and axially on the rod body 24.

[0046] It should be noted that the inner circumferential surface of the preform 1 is conical (tapered). Therefore, if all the heat-absorbing blocks 25 have the same thickness, the gap between the inner circumferential surface of the preform 1 and the heat-absorbing blocks 25 will be different in the vertical (axial) direction. To make the gap approximately the same, the thickness of the heat-absorbing blocks 25 connected to the rod body 24 (or the circumferential surface 24b) can be changed in the vertical direction. For example, the thickness of the heat-absorbing blocks 25 in the vertical direction can be set such that the neck 2 side > the body 3 side (or the bottom 4 side). That is, the thickness of the heat-absorbing blocks 25 located on the neck 2 side (the upper end side of the rod body 24) can be greater than the thickness of the heat-absorbing blocks located on the body 3 side (or the bottom 4 side, the lower end side of the rod body 24).

[0047] Figure 4 This indicates that heat-absorbing blocks 25 are partially installed around the circumference of the rod body 24, which has a regular hexagonal cross-section. Figure 4 The image shows an example where two heat-absorbing blocks 25 are arranged circumferentially and mounted on the rod body 24, with the heat-absorbing blocks 25 partially covering one-third of the outer perimeter of the rod body 24. It should be noted that, for simplicity, in... Figure 4The illustration of the temperature-regulating cavity mold 21 is omitted.

[0048] like Figure 4 As shown, in the preform 1 with the heat-absorbing rod 22 inserted, in the first region in the circumferential direction where the heat-absorbing block 25 is installed ( Figure 4 In the area enclosed by the dashed line, the radial gap S1 between the inner circumferential surface of the preform 1 and the mold is narrowed by the heat-absorbing block 25. In the first region described above, the radiant heat from the preform 1 is easily absorbed by the nearby heat-absorbing block 25, thus the temperature of the preform 1 in the first region is easily reduced.

[0049] On the other hand, in the preform 1 with the heat-absorbing rod 22 inserted, in the second circumferential region where the heat-absorbing block 25 is not installed ( Figure 4 In the region not enclosed by the dashed line, the inner circumferential surface of the preform 1 faces the rod body 24, thus the radial gap S2 between the inner circumferential surface of the preform 1 and the mold is wider than in the first region. In the second region described above, the radiant heat from the preform 1 is absorbed by the rod body 24, which is located further inside than the heat absorber 25, thus the temperature of the preform 1 is difficult to decrease in the second region compared to the first region.

[0050] As described above, by adjusting the installation position of the heat-absorbing block 25 in the heat-absorbing rod 22, the cooling intensity of various parts of the preform 1 can be selectively adjusted, making it easy to make the temperature distribution of the preform 1 approach the desired state. It should be noted that... Figure 4 In the example, the circumferential temperature adjustment of the preform 1 was explained, but the axial temperature of the preform 1 can also be adjusted in the same way.

[0051] (Blow Molding Section 13) The blow molding section 13 performs biaxial stretch blow molding on the preform 1, which has been temperature-adjusted by the temperature adjustment section 12, to manufacture a container.

[0052] The blow molding section 13 includes a blow molding cavity mold, a bottom mold, a stretching rod, and air inlet / outlet components (not shown) that serve as a pair of half-molds corresponding to the shape of the container. The blow molding section 13 performs blow molding while stretching the preform 1. As a result, the preform 1 can be shaped into the shape of the blow molding cavity mold to manufacture a container.

[0053] (Removal section 14) The removal section 14 is configured to release the neck of the container manufactured by the blow molding section 13 from the neck mold 17 and remove the container to the outside of the blow molding apparatus 10.

[0054] <Description of the manufacturing method of the container> Next, the method for manufacturing a container using the blow molding apparatus 10 according to this embodiment will be described. Figure 5 This is a flowchart illustrating the process of manufacturing a container. In this embodiment, a mold adjustment process (S100) is performed before each process (S101 to S104) of the container manufacturing cycle described later.

[0055] (Step S100: Mold adjustment process) The mold adjustment process involves adjusting the installation position of the heat absorber block 25 in the heat absorber rod 22 based on the temperature deviation of the preform 1. As an example, the following operations are performed in the mold adjustment process. In the following explanation, adjustments are made to reduce the deviations in the temperature distribution of the preform 1 and the wall thickness distribution of the container in the circumferential direction. It should be noted that the idea for adjusting the installation position of the heat absorber block 25 in the axial direction is the same as the circumferential direction.

[0056] First, the blow molding device 10 is tested to obtain information on the temperature distribution of the preform 1 before adjustment or the wall thickness distribution of the container.

[0057] For example, if there is uneven temperature distribution in the circumferential direction of the preform 1, the operator installs heat-absorbing blocks 25 in the high-temperature areas facing the preform 1 on the circumferential direction of the rod body 24. As a result, in the circumferential direction of the preform 1, at the high-temperature areas during trial operation, the radiant heat from the preform 1 is easily absorbed by the heat-absorbing blocks 25, thus lowering the temperature. Therefore, the circumferential temperature deviation of the preform 1 is reduced after adjustment.

[0058] Furthermore, when adjusting the installation position of the heat absorber block 25 based on the wall thickness distribution of the container manufactured during trial operation, it can be done in the following manner.

[0059] In a one-stage blow molding process, the high-temperature portion of the preform 1 has significant residual heat, making it easy to stretch. That is, the thinner-walled portions of the container correspond to the high-temperature portions of the preform 1. Conversely, the low-temperature portion of the preform 1 has less residual heat compared to its high-temperature portions, making it difficult to stretch. That is, the thicker-walled portions of the container correspond to the low-temperature portions of the preform 1.

[0060] Therefore, when adjusting the temperature adjustment mold 30 based on the wall thickness distribution of the container, the thinner part of the container wall is regarded as the high temperature part of the preform 1, and the thicker part of the container wall is regarded as the low temperature part of the preform 1. The installation position of the heat absorption block 25 can be adjusted in the same way as above.

[0061] If the above mold adjustment process is completed, then proceed with the various processes of the container manufacturing cycle as shown below.

[0062] (Step S101: Injection molding process) First, in the injection molding section 11, resin is injected from the injection device 15 into the mold space forming the shape of the preform, which is formed by the injection cavity mold, the injection core mold, and the neck mold 17 of the conveying mechanism 16, to produce the preform 1. Then, after the injection (filling and holding pressure) of the resin material is completed, or after a minimum or given cooling time set after the injection is completed, the injection mold of the injection molding section 11 is opened.

[0063] Although there are no particular limitations, from the viewpoint of manufacturing containers with a high-speed molding cycle, it is preferable that in step S101, after the injection (filling and holding) of the resin material is completed, the mold is opened without setting a cooling time for the preform 1 in the injection mold.

[0064] On the other hand, when the preform 1 is cooled to a minimum within the injection mold, it is preferable that the time for cooling the resin material after injection molding 11 has completed the injection of the resin material (cooling time) is less than 1 / 2 of the time for injecting the resin material (injection time). Furthermore, depending on the weight of the resin material, the cooling time relative to the injection time can be set even shorter. For example, the cooling time relative to the injection time is more preferably less than 2 / 5, further preferably less than 1 / 4, and particularly preferably less than 1 / 5.

[0065] In this embodiment, there is no cooling time for the preform 1 in the injection mold (or the cooling time is very short). Therefore, compared with the case where the preform is fully cooled in the injection mold, the skin layer (the surface layer in a solidified state) of the preform is formed thinner, and the core layer (the inner layer in a softened or molten state) is formed thicker. That is, in this embodiment, a preform 1 is formed with a large thermal gradient between the skin layer and the core layer and high residual heat at high temperature.

[0066] Once the injection molding of the preform 1 is completed, the mold of the injection molding section 11 is opened, and the preform 1 is demolded from the injection cavity mold and the injection core mold. Then, the transfer plate of the conveying mechanism 16 moves by rotating a given angle, and the preform 1 held by the neck mold 17 is conveyed to the temperature adjustment section 12 while still containing the residual heat from the injection molding.

[0067] (Step S102: Temperature adjustment process) Next, in the temperature adjustment unit 12, temperature adjustment is performed to bring the temperature of the preform 1 close to the temperature suitable for final blow molding.

[0068] In the temperature adjustment process, the preform 1 held by the neck mold 17 is received in the temperature-regulating cavity mold 21 by the descent of the transfer plate, and the heat-absorbing rod 22 is inserted into the preform 1. Gaps are formed between the temperature-regulating cavity mold 21, the heat-absorbing rod 22 and the preform 1, respectively, and the temperature-regulating cavity mold 21 and the heat-absorbing rod 22 adjust the temperature of the preform 1 to a temperature suitable for blow molding in a non-contact manner.

[0069] As described above, a heat-absorbing block 25 is installed on the main body 24 of the heat-absorbing rod 22, corresponding to the high-temperature portion of the preform 1. Therefore, the high-temperature portion of the preform 1 is cooled more intensely by the heat-absorbing block 25 than other parts, and the temperature deviation of the preform 1 generated during injection molding is also reduced.

[0070] After the temperature adjustment process, the transfer plate of the conveying mechanism 16 moves by rotating a given angle, and the temperature-adjusted preform 1, held by the neck mold 17, is conveyed to the blow molding section 13. It should be noted that, without circulating the cooling medium in the rod body 24 of the heat absorber 22, the rod body 24 and the heat absorber block 25 of the heat absorber 22 are cooled to the outside before being inserted into the preform 1.

[0071] (Step S103: Blow molding process) Next, the container is blow-molded in the blow molding section 13.

[0072] First, the blow molding cavity mold is closed, housing the preform 1 within the mold space. An air inlet / outlet component (e.g., a blow molding core) is lowered, bringing it into contact with the neck 2 of the preform 1. Simultaneously, a tension rod (longitudinal tensioning component) is lowered, pressing against the bottom 4 of the preform 1 from its inner surface, and longitudinal tensioning is performed as needed. At the same time, blow molding air is supplied from the air inlet / outlet component, causing transverse tensioning of the preform 1. Thus, the preform 1 bulges out and is shaped to fit tightly against the mold space of the blow molding cavity mold, forming a container through blow molding. It should be noted that the bottom mold is controlled to remain in a position below the bottom 4 of the preform 1 before the blow molding cavity mold closes, and then rapidly rises to the forming position before or after mold closing.

[0073] (Step S104: Container removal process) Once blow molding is complete, the blow molding cavity is opened. The container can then be moved from the blow molding section 13.

[0074] Next, the transfer plate of the conveying mechanism 16 moves by a given angle and a corresponding amount, and the container is conveyed to the take-out section 14. In the take-out section 14, the neck of the container is released from the neck mold 17, and the container is taken out of the blow molding apparatus 10.

[0075] The above completes one container manufacturing cycle in the container manufacturing method. Afterwards, by moving the transfer plate of the conveying mechanism 16 by a given angle, the steps S101 to S104 described above are repeated. It should be noted that while the blow molding apparatus 10 is operating, the manufacturing of four sets of containers, each with a time difference of one step, is performed in parallel.

[0076] Furthermore, in the structure of the blow molding apparatus 10, the injection molding process, temperature adjustment process, blow molding process, and container removal process each have the same duration. Similarly, the conveying time between each process is also the same duration.

[0077] The effects of this embodiment will be explained below.

[0078] In the temperature adjustment unit 12 of this embodiment, the preform 1 can be cooled from the inside in a non-contact manner by means of a heat-absorbing rod 22 inserted into the preform 1. In addition, the temperature of the preform 1 can also be adjusted from the outside in a non-contact manner by means of a temperature-regulating cavity mold 21.

[0079] In this embodiment, the heat-absorbing rod 22 used for cooling does not contact the preform 1. Therefore, in this embodiment, it is possible to suppress defects such as poor wall thickness distribution of the container caused by excessive cooling of the preform 1, resin sticking (adhesion, adhesion) on the mold during demolding, and deformation of the preform 1 during demolding caused by this.

[0080] For example, materials such as polycarbonate and Tritan are known to have lower strain hardening characteristics compared to materials like PET, making it difficult to adjust wall thickness during blow molding. Strain hardening refers to the characteristic that during the blow molding process, the weakest part of the preform (usually the part with the highest temperature) first reaches its yield point, and then the weaker parts begin to elongate, increasing its strength through molecular orientation until the wall thickness becomes uniform. Therefore, when blow molding preforms 1 made of polycarbonate or Tritan, temperature adjustment before blow molding is crucial. However, according to this embodiment, temperature adjustment of the preform 1 suitable for container molding using polycarbonate or Tritan can be easily performed.

[0081] Furthermore, when the preform 1 is made of PET, during high-cycle molding and shaping into a specific container shape, there are sometimes situations where the PET preform 1 is demolded from the injection molding section 11 (injection molding process) at a high temperature, or the PET preform 1 is heated to a high temperature in the temperature adjustment section 12 (temperature adjustment process). In these cases, a heat absorber 22 can be used to reduce the temperature of the preform 1 as a whole or in a specific area from its inner surface.

[0082] Furthermore, heat-absorbing blocks 25 can be partially installed on the rod body 24 of the heat-absorbing rod 22, corresponding to the high-temperature portion of the preform 1. Within the preform 1, in the area where the heat-absorbing blocks 25 are installed, the radial gap between the inner circumferential surface of the preform 1 and the mold narrows, making it easier to absorb radiant heat from the preform 1. On the other hand, within the preform 1, in the area where the heat-absorbing blocks 25 are not installed, the radial gap between the inner circumferential surface of the preform 1 and the mold widens, making it difficult to absorb radiant heat from the preform 1. The cooling intensity of each part of the preform 1 can be selectively adjusted according to the installation position of the heat-absorbing blocks 25 on the heat-absorbing rod 22, thus allowing for appropriate adjustment of the temperature distribution on the inner circumferential side of the preform.

[0083] This invention is not limited to the above-described embodiments. Various improvements and design changes can be made without departing from the spirit of this invention.

[0084] For example, the configuration of the mounting portion of the heat-absorbing block 25 in the rod body 24 is not limited to the embodiment described above, and the number in the circumferential and axial directions can be arbitrarily changed. For example, when the main body 3 of the preform 1 after injection molding is at a high temperature, the heat-absorbing block 25 can be installed in all the bolt holes (heat-absorbing block connection portions) 24a of the rod body 24.

[0085] Furthermore, in the above embodiment, the radial gap between the preform 1 and the heat absorber 25 can be adjusted by preparing various heat absorber blocks 25 with different radial thicknesses and selecting the type of heat absorber block 25 installed on the rod body 24. Additionally, protrusions or recesses can be formed on the outer peripheral surface of the heat absorber block 25.

[0086] Furthermore, the heat absorber 22 described in the above embodiment is not limited to temperature adjustment of the preform 1, but can also be applied to situations where the stretching ratio of the preform 1 is set differently in the circumferential and axial directions. When the stretching ratio of the preform 1 is set differently, the heat absorber block 25 can be installed at the part where the stretching ratio of the preform 1 is set lower, thereby increasing the cooling intensity of the heat absorber 22 at that part.

[0087] Furthermore, the heat absorber 22 of the above embodiment can also be applied, for example, to the temperature adjustment of a preform 1 formed from a material with lower strain hardening characteristics than PET, such as polyethylene (PE) or high-density polyethylene (HDPE). Alternatively, the heat absorber 22 of the above embodiment can also be applied to the temperature adjustment of a preform 1 formed from PET.

[0088] In the above embodiment, a configuration in which the rod body 24 of the heat-absorbing rod 22 is disposed within the preform 1 at a distance from the inner circumference of the preform 1, and the rod body 24 does not contact the preform 1, has been described. However, as a variation of the above embodiment, such as Figure 6As shown, a front end piece 27 that can abut against the bottom 4 of the preform 1 can also be arranged at the lower end of the rod body 24.

[0089] The preform 1 made of synthetic resins such as polycarbonate shrinks as the temperature decreases. In particular, as described above, the preform 1 used for large containers has a large axial dimension and a thick wall in the main body, therefore, compared to a standard-sized preform, it tends to have a larger axial shrinkage. Therefore, in Figure 6 In this example, a front end piece 27 is positioned at the lower end of the rod body 24, so that the front end piece 27 abuts against the bottom 4 of the axially shrinking preform 1, thereby restricting the axial shrinkage of the preform 1. As a result, the parts cooled by the heat-absorbing block 25 of the heat-absorbing rod 22 and the parts heated by the heating tank are less likely to shift axially from the parts where the temperature of the preform 1 is adjusted, and the temperature adjustment of the preform 1 in the temperature adjustment section 12 can be performed with higher precision.

[0090] The material of the front end piece 27 is not particularly limited, but to prevent the bottom 4 of the preform 1 from overcooling, the front end piece 27 is preferably made of a material with lower thermal conductivity than the material of the rod body 24, such as a resin material. Furthermore, if the front end piece 27 is in contact with the bottom 4 from the very beginning when the heat absorber rod 22 is inserted relative to the preform 1, the bottom 4 of the preform 1 may be overcooled. Therefore, it is preferable to adjust the mounting position of the front end piece 27 so that a given gap is formed between the front end piece 27 and the bottom 4 of the preform 1 when the heat absorber rod 22 is inserted.

[0091] Furthermore, the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the invention is defined not by the foregoing description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0092] Explanation of reference numerals in the attached figures 1: Preform, 2: Neck, 3: Main body, 4: Bottom, 10: Blow molding device, 11: Injection molding part, 12: Temperature adjustment part, 13: Blow molding part, 14: Take-out part, 15: Injection device, 16: Conveying mechanism, 17: Neck mold, 21: Temperature regulating cavity mold, 22: Heat absorber, 23: Core, 24: Rod body, 24a: Bolt hole, 25: Heat absorber block, 26: Bolt, 27: Front end piece.

Claims

1. A mold for temperature adjustment, characterized in that, Used for temperature control of resin-made bottomed cylindrical preforms. The temperature adjustment mold includes: A heat-absorbing rod is inserted into the interior of the preform with a gap from the inner circumference of the preform, for cooling the preform from the inside in a non-contact manner; as well as One or more heat-absorbing blocks are detachably mounted to the heat-absorbing rod in a manner that partially covers it, and the radial gap between the heat-absorbing rod and the preform is adjusted. The heat-absorbing block is thermally connected to the heat-absorbing rod during installation, thereby partially cooling the preform in a non-contact manner.

2. The temperature adjustment mold according to claim 1, wherein, The heat-absorbing rod has multiple mounting parts arranged in the axial and circumferential directions for mounting the heat-absorbing block.

3. The temperature adjustment mold according to claim 1, wherein, A front end piece is installed at the axial front end of the heat absorber rod, which abuts against the bottom of the preform and restricts the axial shrinkage of the preform.

4. The temperature adjustment mold according to claim 1, wherein, The temperature adjustment mold also includes a cavity mold that houses the preform with a gap from the outer periphery of the preform, and adjusts the temperature of the preform from the outside in a non-contact manner.

5. An apparatus for manufacturing resin containers, characterized in that, have: An injection molding section, wherein injection molding yields a resin-made bottomed cylindrical preform. A temperature adjustment unit, wherein the temperature of the preform after injection molding is adjusted; and The blow molding section, wherein the preformed preform, after temperature adjustment, is blow molded while incorporating the residual heat from injection molding, to manufacture resin containers. The temperature adjustment unit has a temperature adjustment mold according to any one of claims 1 to 4, and cools the preform from the inside in a non-contact manner by inserting the heat-absorbing rod on which the heat-absorbing block is mounted into the preform.

6. The apparatus for manufacturing resin containers according to claim 5, wherein, In the injection molding section, the time for cooling the resin material in the injection mold after the injection of the resin material is completed is less than 1 / 2 of the time for injecting the resin material into the injection mold.

7. The apparatus for manufacturing resin containers according to claim 5, wherein, The material of the preform is any one of polycarbonate, Tritan, polyethylene, high-density polyethylene, and polyethylene terephthalate.

8. A method for manufacturing a resin container, characterized in that, have: Injection molding process, wherein injection molding yields a resin preform with a bottomed cylindrical shape; The temperature adjustment process includes adjusting the temperature of the preform after injection molding; and The blow molding process involves blow molding the preformed section after temperature adjustment, while still containing the residual heat from injection molding, to manufacture a resin container. In the temperature adjustment process, the heat-absorbing rod with the heat-absorbing block installed is inserted into the preform using the temperature adjustment mold according to any one of claims 1 to 4, thereby cooling the preform from the inside in a non-contact manner.

9. The method for manufacturing a resin container according to claim 8, wherein, The method for manufacturing the resin container further includes: In the mold adjustment process, the installation position of the heat-absorbing block is adjusted based on information about the temperature distribution of the preform or the wall thickness distribution of the container. After the mold adjustment process, the injection molding process, the temperature adjustment process, and the blow molding process are performed.

10. The method for manufacturing a resin container according to claim 8, wherein, In the injection molding process, the time for cooling the resin material in the injection mold after the injection of the resin material is completed is less than 1 / 2 of the time for injecting the resin material into the injection mold.

11. The method for manufacturing a resin container according to claim 8, wherein, The material of the preform is any one of polycarbonate, Tritan, polyethylene, high-density polyethylene, and polyethylene terephthalate.

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