Temperature adjustment mold, resin container manufacturing apparatus, and manufacturing method

Abstract

Provided is a temperature adjustment mold capable of adjusting the temperature of a preform from the inside of the preform while restricting the shrinkage deformation of the preform. A temperature adjustment mold for adjusting the temperature of a bottomed preform made of resin after injection molding includes a rod portion inserted into the inside of the preform and extending in the axial direction of the preform. The rod portion has a ring-shaped protrusion portion protruding in the radial direction of the rod portion and contacting the inner peripheral surface of the preform. The rod portion contacts the bottom of the preform to restrict the axial shrinkage of the preform. The protrusion portion restricts the radial shrinkage of the preform and conducts heat between the rod portion and the preform to adjust the temperature at a given position in the axial direction of the preform.

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 of the manufacturing devices for resin containers. Hot preform blow molding apparatuses utilize the heat retained during the injection molding of a preform to blow mold resin containers. Compared to cold preform blow molding apparatuses, they are advantageous in that they can 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 the container. Therefore, in a hot preform blow molding cycle, a preform temperature adjustment process is performed between the injection molding and blow molding processes to suppress excessive preform temperature or to impart the desired temperature distribution to the preform suitable for shaping the container.

[0004] In this temperature adjustment process, a temperature adjustment rod mold that mimics the internal shape of the pre-plasticized blank is sometimes inserted into the inside of the pre-plasticized blank, so that the inner circumferential surface of the pre-plasticized blank is in close contact with the temperature adjustment rod mold for temperature adjustment.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 3330677

[0008] Patent Document 2: Japanese Patent No. 3255485 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] Conventional temperature control rods, being in close contact with the inner circumferential surface of the preform, are unsuitable for temperature control that imparts an axial temperature difference. Therefore, for example, it is difficult to simultaneously limit the shrinkage and deformation of the preform while locally cooling the portion corresponding to the thin-walled section of the container from the inside of the preform, thereby improving the container's wall thickness distribution.

[0011] Methods for solving problems

[0012] One aspect of the invention is a temperature adjusting mold for adjusting the temperature of a bottom-shaped resin preform for injection molding. The temperature adjusting mold includes a rod that is inserted into the interior of the preform and extends axially along the preform. The rod has an annular protrusion that projects radially from the rod and contacts the inner circumferential surface of the preform. The rod contacts the bottom of the preform, thus restricting axial shrinkage of the preform. The protrusion restricts radial shrinkage of the preform and conducts heat between the rod and the preform, adjusting the temperature at a given location along the axial direction of the preform.

[0013] Invention Effects

[0014] According to one aspect of the invention, it is possible to limit the shrinkage deformation of the preform while simultaneously performing axial localized temperature adjustment from the inside of the preform. Attached Figure Description

[0015] Figure 1 This is a diagram schematically illustrating the structure of the blow molding apparatus of this embodiment.

[0016] Figure 2 This is a longitudinal cross-sectional view showing a structural example of the temperature adjustment unit.

[0017] Figure 3 This is a cross-sectional view near the protrusion of the temperature adjustment section.

[0018] Figure 4 It means Figure 2 A diagram of a variation.

[0019] Figure 5 It means Figure 4 A diagram of a variation.

[0020] Figure 6 It means Figure 2 Figures of other variations.

[0021] Figure 7 This is a flowchart illustrating the steps involved in the blow molding process. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0023] In the embodiments, to facilitate understanding, structures and elements other than the main parts of the invention are simplified or omitted in the description. Furthermore, in the accompanying drawings, the same symbols are used to denote the same elements. It should be noted that the shapes, dimensions, etc., of the elements shown in the drawings are schematic representations and do not represent actual shapes, dimensions, etc.

[0024] Figure 1This is a schematic diagram illustrating the structure of the blow molding apparatus 20 of this embodiment. The blow molding apparatus 20 of this embodiment is a hot preform method (also known as a one-stage method) that uses the heat retained during injection molding (internal heat) to blow mold a container without cooling the preform 10 to room temperature.

[0025] The blow molding apparatus 20 includes an injection molding section 21, a temperature adjustment section 22, a blow molding section 23, a take-out section 24, and a conveying mechanism 26. The injection molding section 21, the temperature adjustment section 22, the blow molding section 23, and the take-out section 24 are positioned at a position that rotates by a given angle (e.g., 90 degrees) around the conveying mechanism 26 each time.

[0026] (Conveying mechanism 26)

[0027] Conveying mechanism 26 is equipped with Figure 1 The transfer plate 28 moves by rotating around an axis perpendicular to the paper plane. Figure 1 (Not shown in the figure). On the transfer plate 28, one or more neck molds 27 are arranged at given angles to hold the neck of the preform 10 or the resin container (hereinafter referred to as the container). Figure 1 (Not shown in the figure). The conveying mechanism 26 moves the transfer plate 28 by 90 degrees each time, thereby conveying the preform 10 (or container) held by the neck mold 27 in the order of injection molding section 21, temperature adjustment section 22, blow molding section 23, and take-out section 24. It should be noted that the conveying mechanism 26 also has a lifting mechanism (a longitudinal mold opening and closing mechanism), a mold opening mechanism for the neck mold 27, and performs actions involved in lifting the transfer plate 28, closing the mold of the injection molding section 21, and opening the mold (demolding).

[0028] (Injection Molding Section 21)

[0029] Injection molding section 21 includes an injection cavity mold and an injection core mold (not shown in the figure), for manufacturing... Figure 2 The preform 10 is shown. An injection device 25 for supplying resin material, which serves as the raw material for the preform 10, is connected to the injection molding section 21.

[0030] In the injection molding section 21, the aforementioned injection cavity mold, injection core mold, and neck mold 27 of the delivery mechanism 26 are closed to form a mold space in the shape of a preform. Then, by flowing resin material from the injection device 25 into such a preform-shaped mold space, a preform 10 is manufactured in the injection molding section 21.

[0031] For example, the preform 10 has an overall shape that is a bottomed cylindrical shape with one end open and the other end closed. A neck is formed at the end of the preform 10 on the open side.

[0032] Furthermore, the materials for the container and the preform 10 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), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPSU (polyphenylsulfone), PS (polystyrene), COP / COC (cyclic olefin polymer), PMMA (polymethyl methacrylate: propylene), PLA (polylactic acid), etc.

[0033] It should be noted that even when the injection molding section 21 is opened, the neck mold 27 of the conveying mechanism 26 remains closed and continues to hold and convey the preform 10 unchanged. The number of preforms 10 simultaneously molded in the injection molding section 21 (i.e., the number of containers that can be simultaneously molded by the blow molding device 20) can be appropriately set.

[0034] (Temperature adjustment unit 22)

[0035] The temperature adjustment unit 22 homogenizes and removes temperature deviations in the preform 10 manufactured in the injection molding unit 21, adjusting the temperature of the preform 10 to a temperature suitable for blow molding (e.g., approximately 90°C to 105°C) and a temperature distribution suitable for the shape of the container to be formed. In addition, the temperature adjustment unit 22 also has the function of cooling the preform 10 at a high temperature after injection molding.

[0036] Figure 2 This is a longitudinal cross-sectional view showing a structural example of the temperature adjustment unit 22. The temperature adjustment unit 22 includes a cavity mold (temperature adjustment tank mold, heating tank mold) 31 capable of accommodating the pre-plasticized blank 10 and a mold component, namely a temperature adjustment rod 32, inserted into the inside of the pre-plasticized blank.

[0037] The cavity mold 31 has a temperature adjustment space with a shape that is substantially the same as that of the preform 10 manufactured in the injection molding section 21. The cavity mold 31 is divided into at least three parts in the axial direction of the preform 10, including an upper mold 31a, a middle mold 31b, and a lower mold 31c.

[0038] The upper die 31a is a die facing the outer peripheral surface near the neck of the preformed parison 10. The middle die 31b is a die facing the outer peripheral surface of the main body of the preformed parison 10. The lower die 31c is a die facing the outer peripheral surface of the bottom of the preformed parison 10. The bottom surface of the upper die 31a and the upper surface of the middle die 31b, as well as the bottom surface of the middle die 31b and the upper surface of the lower die 31c, are respectively engaged by a fitting structure (Japanese original text: インロー構造) in such a way that a heat insulating member is sandwiched between them.

[0039] Heating members (not shown), such as belt heaters (ring heaters) and rod heaters, are respectively installed in the upper die 31a, the middle die 31b, and the lower die 31c of the cavity die 31. The upper die 31a, the middle die 31b, and the lower die 31c are respectively maintained at a given temperature by the heating members. Then, by heating the outer peripheral side of the preformed parison 10 using the heat from the cavity die 31, the temperature of the preformed parison 10 is adjusted. The main body of the heated preformed parison 10 contracts and deforms toward the inner diameter side and the neck side. It should be noted that by changing the temperature of the heating members of the upper die 31a, the middle die 31b, and the lower die 31c, the temperature distribution in the axial direction of the preformed parison 10 can also be changed.

[0040] The temperature adjustment rod 32 is an example of a rod portion (rod member) and is configured to be able to advance and retreat axially (the vertical direction in the figure) with respect to the neck die 27 holding the preformed parison 10 in the temperature adjustment portion 22. In Figure 2 it shows the state where the temperature adjustment rod 32 moves downward (descends) in the figure through a rod drive mechanism (not shown) and is inserted into the inside of the neck die 27 and the preformed parison 10.

[0041] The diameter of the temperature adjustment rod 32 is set to a size smaller than the inner diameter of the preformed parison 10. In addition, the front end of the temperature adjustment rod 32 inserted into the inside of the preformed parison 10 contacts the bottom of the preformed parison 10. The axial length of the temperature adjustment rod 32 is set to a length assuming the shrinkage amount of the preformed parison 10 from when it is removed from the injection molding portion 21 until the temperature adjustment rod 32 is inserted. Thus, the temperature adjustment rod 32 has the function of maintaining the axial length of the preformed parison 10 at a specified size during temperature adjustment and restricting unnecessary shrinkage of the preformed parison 10.

[0042] In addition, inside the temperature adjustment rod 32, a flow path (not shown) for the temperature adjustment medium to flow is formed along the axial direction. Therefore, the temperature adjustment rod 32 is maintained at a given temperature by the temperature adjustment medium flowing inside. In this embodiment, the case where the temperature adjustment rod 32 is set to a lower temperature than the preformed parison 10 and the preformed parison 10 is cooled by the temperature adjustment rod 32 is described, but the preformed parison 10 can also be heated by the temperature adjustment rod 32.

[0043] In addition, the temperature adjustment lever 32 has an annular protrusion 33 that protrudes radially outward. Figure 3 This is a cross-sectional view near the protrusion of the temperature adjustment section 22. Additionally, in Figure 3 The flow path diagram inside the temperature adjustment lever 32 is also omitted.

[0044] Figure 2 , Figure 3 The protrusion 33 shown is composed of a pair of semi-segmented rings 34, which are detachable from the temperature adjustment rod 32 and are made of a material with good thermal conductivity. Each semi-segmented ring 34 has a large-diameter annular portion (protrusion 33) on its outer periphery and its mounting position can be adjusted axially with the temperature adjustment rod 32. The pair of semi-segmented rings 34 (protrusions 33) are fixed to the temperature adjustment rod 32 by a fixing unit (not shown).

[0045] The protrusion 33 functions to adjust the temperature of a given portion of the preform 10 by contacting it axially from the inside. At the portion of the preform 10 that contacts the protrusion 33, heat is conducted between the protrusion 33 and the temperature adjustment rod 32. Conversely, at the portion of the preform 10 that does not contact the protrusion 33, heat from the temperature adjustment rod 32 is difficult to transfer because air is between the temperature adjustment rod 32 and the preform 10. Therefore, the axial temperature distribution of the preform 10 can be adjusted by the position of the protrusion 33.

[0046] Furthermore, as described above, by having the protrusion 33 contact the inner circumference of the pre-plasticized blank 10, the pre-plasticized blank 10 becomes less likely to shrink towards the inner diameter side than the protrusion 33. Therefore, the protrusion 33 also serves to limit the shrinkage of the pre-plasticized blank 10 beyond what is necessary by maintaining the radial dimension of the pre-plasticized blank 10 during temperature adjustment.

[0047] Furthermore, the outer diameter of the protrusion 33 is appropriately set based on the temperature settling time of the protrusion 33, taking into account the shrinkage amount of the pre-plasticized blank 10. If the outer diameter of the protrusion 33 is increased, the shrinking pre-plasticized blank 10 contacts the protrusion 33 more quickly, and the temperature settling time based on the contact with the protrusion 33 becomes longer. On the other hand, if the outer diameter of the protrusion 33 is decreased, the contact between the shrinking pre-plasticized blank 10 and the protrusion 33 becomes slower compared to the case with a larger outer diameter of the protrusion 33, and the aforementioned temperature settling time becomes shorter. Therefore, by adjusting the outer diameter of the protrusion 33, the contact time between a given part of the pre-plasticized blank 10 and the protrusion 33 changes, and the temperature settling time for a given part of the pre-plasticized blank 10 can be adjusted. The above adjustment can be performed, for example, by preparing various semi-segmented rings 34 with different outer diameters of the protrusion 33, and appropriately changing the semi-segmented rings 34 according to the specifications such as the shape of the manufactured container and the material of the pre-plasticized blank 10.

[0048] exist Figure 2 The image shows an example where a protrusion 33 is positioned at the axial center of a temperature adjustment rod 32 to cool a corresponding portion of the preform 10 that forms the shoulder of the container. By locally cooling the portion of the preform 10 corresponding to the shoulder of the container, the heat retention is reduced, which allows for thickening of the container shoulder wall during blow molding and improves the container wall thickness distribution.

[0049] Figure 4 yes Figure 2 A modified example shows an instance where the protrusion 33 is used to cool the area near the boundary between the neck mold 27 and the upper mold 31a (the corresponding portion below the neck of the preform 10). Figure 4 In, also with Figure 2 Similarly, in this example, the protrusion 33 is formed by a pair of semi-divided rings 34. According to... Figure 4 For example, by locally cooling the area below the neck to reduce the fluidity of the resin in that area, it is possible to suppress the formation of burrs in the gap between the neck mold 27 and the upper mold 31a or between the neck mold 27 and the upper surface of the blow mold.

[0050] Figure 5 yes Figure 4 A variation is shown where a protrusion 33 is integrally formed on the temperature adjustment lever 32 at a location below the neck. Figure 5 In the example, we can also obtain the same Figure 4 The same effect.

[0051] Figure 6 yes Figure 2 Other variations show a structure in which an annular contact ring 35 constituting the protrusion 33 and a cylindrical spacer 36 cover the temperature adjustment rod 32. Additionally, Figure 6 The structure and function of cavity mold 31 Figures 2 to 5 Since they are the same, repeated descriptions are omitted.

[0052] The inner diameters of the annular contact ring 35 and the cylindrical spacer 36 are respectively set to dimensions through which the temperature adjustment rod 32 can be inserted. At least one contact ring 35 and at least one (more preferably two) spacer 36 are inserted into the temperature adjustment rod 32, concentrically arranged on the outer periphery of the rod body 32b of the temperature adjustment rod 32. It should be noted that... Figure 6 The image shows an example where two contact rings 35 and spacers 36 are installed on each of the temperature adjustment rods 32.

[0053] The outer diameter of the contact ring 35 is set to be larger than the outer diameter of the spacer 36. The contact ring 35, mounted on the temperature adjustment rod 32, protrudes outward from the spacer 36 and contacts the inner side of the preform 10, conducting heat from the preform 10 to the temperature adjustment rod 32. Therefore, the contact ring 35 functions as a protrusion 33 that contacts a given axial portion of the preform 10 from the inside to adjust (cool) the temperature of that given portion.

[0054] The spacer 36 is mounted on the temperature adjustment rod 32 to position the contact ring 35 axially. Furthermore, the spacer 36, for example, does not contact the preform 10, but functions to form an air layer between itself and the inner circumference of the preform 10. As described above, the axial temperature distribution of the preform 10 can be adjusted by the position of the contact ring 35.

[0055] Additionally, the temperature adjustment lever 32 has a front end member 32a. The diameter of the front end member 32a is larger than the diameter of the lever body 32b, and the front end member 32a can be attached and detached relative to the front end of the lever body 32b. The contact ring 35 and the spacer 36 are inserted into the lever body 32b with the front end member 32a removed. The front end member 32a is installed at the front end of the lever body 32b after the contact ring 35 and the spacer 36 have been inserted into the lever body 32b, preventing the contact ring 35 and the spacer 36 from falling off. More specifically, after the stepped portion of the lower end (front end) of the temperature adjustment lever 32 is received in the recess at the upper end of the front end member 32a, a stop pin (not shown) is inserted into the through holes formed in the temperature adjustment lever 32 and the front end member, respectively, to prevent the contact ring 35 and the spacer 36 from falling off. The spacer 36 and the front end member 32a function as fixing units to fix the contact ring 35 (protrusion 33) to the temperature adjustment lever 32.

[0056] exist Figure 6 In the example, we can also obtain the same Figure 2 The same effect. It should be noted that, in Figure 6 In the example, the outer diameter and number of contact rings 35, and the axial position of the contact rings 36 as specified by the spacer 36, can be appropriately changed by replacing the contact rings 35 and the spacer 36.

[0057] (Blow Molding Section 23)

[0058] return Figure 1 The blow molding section 23 stretches and blow molds the pre-plasticized blank 10, which has been temperature-adjusted by the temperature adjustment section 22, to manufacture a container.

[0059] The blow molding section 23 includes a blow molding cavity mold, a bottom mold, a stretching rod, and an air inlet component (blow molding core mold, not shown) that serve as a pair of parting molds corresponding to the shape of the container. The blow molding section 23 performs blow molding while stretching the pre-plasticized preform 10. As a result, the pre-plasticized preform 10 can be shaped into the shape of the blow molding cavity mold to manufacture a container.

[0060] (Removal section 24)

[0061] The removal section 24 is configured to open the neck of the container manufactured by the blow molding section 23 from the neck mold 27 and remove the container to the outside of the blow molding apparatus 20.

[0062] (Explanation of blow molding method)

[0063] Next, the blow molding method of the blow molding apparatus 20 based on this embodiment will be described.

[0064] Figure 7 This is a flowchart illustrating the steps of the blow molding method. In this embodiment, a mold adjustment step (S100) is performed before each step (S101 to S104) of the blow molding method described later.

[0065] (Step S100: Mold Adjustment Process)

[0066] The mold adjustment process involves adjusting the position of the protrusion 33 of the temperature adjustment rod 32 according to the shape of the container to be shaped. As an example, the following operations are performed in the mold adjustment process.

[0067] First, the blow molding apparatus 20 is tested to obtain information about the container shape before adjustment. Next, based on the container shape information, the axial position of the protrusion 33 of the temperature adjustment rod 32 is adjusted. At this time, the outer diameter of the protrusion 33 can also be changed by modifying components, thereby altering the temperature adjustment time based on the temperature adjustment rod 32.

[0068] For example, in the case where there is a thin-walled portion in the axial direction of the container, the operator adjusts the position of the protrusion 33 of the temperature adjustment rod 32 so that the portion of the pre-plasticized blank 10 corresponding to the thin-walled portion of the container comes into contact with the protrusion 33. As a result, the portion of the pre-plasticized blank 10 corresponding to the thin-walled portion of the container comes into contact with the protrusion 33 and is locally cooled, thereby improving the wall thickness distribution of the adjusted container.

[0069] Additionally, for example, if burrs are generated below the neck of the container, the operator adjusts the temperature adjustment rod 32 so that the protrusion 33 is located near the boundary between the neck mold 27 and the upper mold 31a (the corresponding part below the neck of the preform 10). As a result, the part below the neck of the preform 10 is locally cooled, thereby suppressing the generation of burrs below the neck of the container.

[0070] Once the above mold adjustment process is completed, proceed with the blow molding cycle processes shown below.

[0071] (Step S101: Injection Molding Process)

[0072] In step S101, in the injection molding section 21, resin is injected from the injection device 25 into the mold space of the preform shape formed by the injection cavity mold, the injection core mold and the neck mold 27 of the conveying mechanism 26 to produce the preform 10.

[0073] In step S101, when the injection molding of the preform 10 is completed, the injection molding section 21 opens the mold, and the preform 10 is demolded from the injection cavity mold and the injection core mold. Then, the transfer plate 28 of the conveying mechanism 26 moves by rotating a given angle, and the preform 10 held in the neck mold 27 is conveyed to the temperature adjustment section 22.

[0074] (Step S102: Temperature Adjustment Process)

[0075] Next, in the temperature adjustment unit 22, temperature adjustment is performed to bring the temperature of the preform 10 close to the temperature suitable for final blow molding.

[0076] During the temperature adjustment process, the preform 10, which is held in the neck mold 27, is received in the cavity mold 31 by the descent of the transfer plate 28. In addition, the temperature adjustment rod 32 is lowered and inserted into the preform 10.

[0077] In the temperature adjustment section 22, the preform 10 is heated from the outside in a non-contact state using the cavity mold 31. This adjusts the temperature of the preform 10 to a level suitable for blow molding, thereby reducing overheating during injection molding. Furthermore, due to the shrinkage of the preform 10, its inner circumferential surface contacts the protrusion of the temperature adjustment rod 32, thereby locally cooling a specific area of ​​the preform 10.

[0078] After the temperature adjustment process, the transfer plate 28 of the conveying mechanism 26 moves by rotating a given angle, and the pre-plasticized preform 10, which has been temperature adjusted and is held in the neck mold 27, is conveyed to the blow molding section 23.

[0079] (Step S103: Blow molding process)

[0080] Next, the container is blow-molded in the blow molding section 23.

[0081] First, the blow molding cavity is closed, housing the preform 10 within the mold space. The air inlet member (blow molding core) is lowered, bringing it into contact with the neck of the preform 10. Then, the tension rod (longitudinal tension member) is lowered, pressing the bottom of the preform 10 from its inner surface. Simultaneously, longitudinal tension is applied as needed, while blow molding air is supplied from the air inlet member, thereby stretching the preform 10 laterally. As a result, the preform 10 bulges out and is shaped to fit tightly against the mold space of the blow molding cavity, thus blow molding it into a container. It should be noted that the bottom mold remains in a position below the preform 10 before the blow molding cavity is closed, not in contact with the bottom of the preform 10, and rapidly rises to the molding position before or after mold closure.

[0082] (Step S104: Container Removal Process)

[0083] When blow molding is complete, the blow molding cavity mold and bottom mold are opened. This allows the container to move from the blow molding section 23.

[0084] Next, the transfer plate 28 of the conveying mechanism 26 moves by a given rotation angle, and the container is conveyed to the take-out section 24. In the take-out section 24, the neck of the container opens from the neck mold 27, and the container is taken out of the blow molding apparatus 20.

[0085] The above completes the series of processes in the blow molding cycle. Then, by moving the transfer plate 28 of the conveying mechanism 26 by a given rotation angle, the processes S101 to S104 described above are repeated. While the blow molding apparatus 20 is operating, the manufacturing of four sets of containers, each with a time difference of one process, is performed in parallel.

[0086] The effects of this embodiment will be explained below.

[0087] In this embodiment, the temperature adjustment rod 32 has an annular protrusion 33 that protrudes radially and contacts the inner circumferential surface of the preform 10. The protrusion 33 conducts heat between the temperature adjustment rod 32 and the preform 10. Therefore, in this embodiment, the temperature can be adjusted by cooling a given portion of the preform 10 axially from the inside using the protrusion 33, thereby improving the wall thickness distribution of the blow-molded container.

[0088] Furthermore, the front end of the temperature adjustment rod 32 contacts the bottom of the preform 10, thus limiting the axial shrinkage of the preform 10. Additionally, the protrusion 33 contacts the inner circumferential surface of the preform 10, thereby limiting the radial shrinkage of the preform 10. As a result, deviations in the shape of the preform 10 during temperature adjustment can be suppressed, and an appropriate temperature distribution can be easily imparted to the preform 10 in each blow molding cycle.

[0089] Furthermore, in this embodiment, the protrusion 33 is provided on the semi-segmented ring 34 or contact ring 35, which can be attached to and detached from the temperature adjustment rod 32, allowing for axial position adjustment. This enables easy adjustment of the position for temperature adjustment of the pre-plasticized preform 10 according to container specifications, etc.

[0090] Alternatively, the radial protrusion of the protrusion 33 can be changed by replacing the semi-segmented ring 34 or the contact ring 35. This allows for variation in the timing of contact between the shrinking preform 10 and the protrusion 33, thus adjusting the temperature settling time of the protrusion 33.

[0091] Here, when the material of the preform 10 is polyethylene (PE) or high-density polyethylene (HDPE), it has a higher thermal shrinkage rate compared to PET and the like, making it prone to shrinkage and deformation during temperature adjustment. Furthermore, these materials are known to lack strain hardening characteristics compared to PET, making wall thickness adjustment during blow molding difficult. 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 PE or HDPE preforms, it is crucial to perform appropriate temperature adjustment before blow molding while suppressing shrinkage and deformation of the preform. According to this embodiment, temperature adjustment of the preform suitable for PE or HDPE container molding can be easily performed.

[0092] 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.

[0093] For example, in the above embodiment, multiple protrusions 33 may be provided in the axial direction of the temperature adjustment rod 32.

[0094] Furthermore, the embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. 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.

[0095] Symbol Explanation

[0096] 10…Pre-plastic preform, 20…Blow molding device, 21…Injection molding section, 22…Temperature adjustment section, 23…Blow molding section, 31…Cavity mold, 32…Temperature adjustment rod, 33…Protrusion, 34…Semi-segmented ring.

Claims

1. A temperature-adjusting mold for adjusting the temperature of a bottom-shaped resin preform after injection molding, wherein, The temperature adjustment mold includes a rod portion that is inserted into the interior of the pre-plasticized preform and extends along the axial direction of the pre-plasticized preform. The rod portion has an annular protrusion that projects radially toward the rod portion and contacts the inner circumferential surface of the preform. The rod portion contacts the bottom of the preform to restrict the axial shrinkage of the preform. The protrusion restricts the radial shrinkage of the preform and conducts heat between the rod and the preform, adjusting the temperature at a given location in the axial direction of the preform. The protrusion can adjust the position of the axial direction.

2. The temperature adjustment mold according to claim 1, wherein, The protrusion can be attached to or detached from the rod.

3. The temperature adjustment mold according to claim 1 or 2, wherein, The temperature adjustment mold also includes a cavity mold for receiving the pre-plasticized blank and heating the pre-plasticized blank from the outer peripheral side.

4. An apparatus for manufacturing a resin container, comprising: The injection molding section performs injection molding on a resin preform with a bottom shape. A temperature adjustment unit, which uses a temperature adjustment mold according to any one of claims 1 to 3 to adjust the axial temperature distribution for the preform containing heat retained during injection molding; and The blow molding section blow molds the pre-plasticized preform after temperature adjustment to manufacture resin containers.

5. A method for manufacturing a resin container, comprising: The injection molding process involves injection molding a resin preform with a bottom shape. In the temperature adjustment process, for the preform containing heat retained during injection molding, the axial temperature distribution is adjusted using a temperature adjustment mold according to any one of claims 1 to 3; and The blow molding process involves blow molding the pre-plasticized preform after temperature adjustment to manufacture resin containers.

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