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

Abstract

A temperature adjustment mold for temperature adjustment of a bottomed tubular preform used for blow molding of a resin-made container, and having: a cavity mold that houses the preform inside and contacts an outer surface of the preform; and a cooling mold that is inserted into the preform, and performs cooling by introducing compressed air into the preform. The cavity mold houses a ring-shaped heat insulating member having a heat insulating region with a lower thermal conductivity than that of the cavity mold in a replaceable manner. The heat insulating member is arranged at an outer periphery of a target site of the preform corresponding to a grounding portion of the container, and abuts against the target site to adjust a temperature of the target site to a higher temperature than other sites.

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 heat retained during the injection molding of a preform to blow mold the structure of the resin container. Compared to cold preform blow molding apparatuses, they have an advantage 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 into a container. Therefore, in the hot preform container manufacturing cycle, in order to suppress temperature deviations (temperature inconsistencies) in the preform or to impart the desired temperature distribution to the preform suitable for shaping into a container, a preform temperature adjustment process is performed between the injection molding and blow molding processes.

[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 in 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, for example, as in Patent Document 1 and Patent Document 2, it is proposed to introduce compressed air into the inside of the preform and press the outer periphery of the preform onto the mold surface, thereby cooling the preform from the inside and outside.

[0006] Prior art literature Patent documents Patent Document 1: Japanese Patent No. 6778355 Patent Document 2: Japanese Patent No. 6505344 Summary of the Invention

[0007] The problem that the invention aims to solve For example, in the manufacture of large containers ranging from 12L to 20L using hot preform blow molding, the preform is characterized by its slender shape, thick walls, and heavy weight. It also retains a large amount of heat and is easy to stretch. On the other hand, in large containers, to ensure specifications such as flexural strength and drop resistance, the outer edge (heel) of the bottom needs to be thickened. Therefore, the temperature control of the preform must address the thickening of the heel.

[0008] Furthermore, the preform used for large containers is approximately the same length as the container, and during blow molding, it is generally only stretched along the transverse axis. Therefore, in the blow molding of large containers, the bottom of the preform easily contacts the bottom mold shortly after the blow molding process begins. Consequently, due to this contact with the bottom mold, the bottom contact area of ​​the container becomes a wall thickness exceeding what is necessary. On the other hand, it is difficult for the base of the container to become a thick wall, and there is still room for improvement in this regard.

[0009] Therefore, the present invention was made in view of such problems, and its object is to provide a temperature adjustment mold that can appropriately adjust the temperature of a preform corresponding to the thickening of the base of a resin container.

[0010] Technical solutions for solving the problem One aspect of the present invention provides a temperature-adjusting mold for adjusting the temperature of a bottomed cylindrical preform used in blow molding for a resin container. The temperature-adjusting mold comprises: a cavity mold that houses the preform and contacts its outer surface; and a cooling mold inserted into the preform to cool it by introducing compressed air. The cavity mold replaceably houses an annular heat-insulating member having an insulating region with a lower thermal conductivity than that of the cavity mold. The heat-insulating member is disposed on the outer periphery of a target portion of the preform corresponding to the grounding portion of the container, and abuts against the target portion to adjust its temperature to be higher than that of other portions.

[0011] Invention Effects According to one aspect of the present invention, a temperature-adjusting mold is provided that can appropriately adjust the temperature of a preform corresponding to the thickening of the base portion of a resin container. Attached Figure Description

[0012] Figure 1 This is a diagram showing an example of a preform used in the manufacture of a container in this embodiment.

[0013] Figure 2 It means to Figure 1 An example of a container manufactured by shaping a pre-plasticized preform.

[0014] Figure 3 This is a schematic diagram illustrating the structure of the blow molding apparatus of this embodiment.

[0015] Figure 4 This is a longitudinal sectional view showing a structural example of the temperature adjustment unit in this embodiment.

[0016] Figure 5 It means Figure 4 The diagram shows a structural example of the base block component.

[0017] Figure 6 It is a flowchart illustrating the process of manufacturing a container. Detailed Implementation

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

[0019] 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 drawings, the same symbols are used to denote the same elements. Additionally, the shapes, dimensions, etc., of the elements shown in the drawings are schematic and do not represent actual shapes, dimensions, etc.

[0020] Figure 1 This is a diagram showing an example of a preform 1 used in the manufacture of a resin container (hereinafter also simply referred to as a container) in this embodiment. Figure 2 It means to Figure 1 A figure shows an example of a resin container manufactured by molding a pre-plasticized preform 1.

[0021] like Figure 1 As shown, the preform 1 has an overall shape of a bottomed cylindrical shape with one end open and the other end closed. The preform 1 has: a neck 2 formed on one end and having an opening, a main body 3 connected to the neck 2 and formed into a cylindrical shape, and a bottom 4 connected to the main body 3 and closing the other end.

[0022] in addition, Figure 2 The container 10 shown in this embodiment is, for example, a large container used in water dispensers, with a capacity of 12 to 20 liters. Furthermore, the container 10 is reusable and rebottled.

[0023] The container 10 is common to the preform 1 and has: a neck 2 formed on one end side and having an opening, a shoulder 11 that expands from the neck 2, a main body 12 connected to the shoulder 11 and formed into a cylindrical shape, and a bottom 13 connected to the main body 12 and closing the other end side.

[0024] Additionally, the bottom 13 of the container 10 has a base portion 13a, a grounding portion 13b, and an upper bottom portion 13c. The base portion 13a is formed on the outer edge of the bottom 13 and is connected to the main body portion 12. The grounding portion 13b is formed in a ring shape on the inner circumferential side of the base portion 13a. The upper bottom portion 13c is formed in the central portion of the container, which is closer to the inner circumference of the grounding portion 13b than the grounding portion 13b, and is further inward of the container 10 than the grounding portion 13b. Figure 2 (Upper side) Recessed. In addition, in order to ensure the bending strength and drop resistance of the container 10, the wall thickness of the heel 13a is set to be thicker than that of the ground part 13b and the upper bottom 13c.

[0025] Here, the materials for the preform 1 and the container 10 are thermoplastic synthetic resins, which can be appropriately selected according to the application of the container 10. 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: acrylic acid), PLA (polylactic acid), etc. Although not particularly limited, the materials for the preform 1 and the container 10 in this embodiment are, for example, polyethylene terephthalate (PET), polycarbonate (PC), or Tritan.

[0026] Figure 3 This is a schematic diagram illustrating the structure of the blow molding apparatus 20 of this embodiment, which is suitable for the manufacture of containers. The blow molding apparatus 20 is an example of a container manufacturing apparatus, which employs a hot preform method (also known as a one-stage method) to blow mold a container using the heat retained during injection molding (internal heat) without cooling the preform 1 to room temperature.

[0027] 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 each positioned at a given rotation angle (e.g., 90 degrees) about the conveying mechanism 26.

[0028] (Conveying mechanism 26) Conveying mechanism 26 is equipped with the ability to... Figure 3 A transfer plate (not shown) moves in a rotational direction centered on an axis perpendicular to the paper surface. The transfer plate consists of a single disc-shaped flat plate member or multiple generally fan-shaped flat plate members divided according to each forming station. On the transfer plate, at given angles (e.g., 90°) relative to the center of the transfer plate, one or more neck molds 27 are respectively arranged to hold the neck 2 (or neck 2 of container 10) of the preform 1. Figure 3 (Not shown in the image).

[0029] The conveying mechanism 26 has a rotating mechanism (not shown) that, by moving the transfer plate, sequentially conveys the preform 1 (or container 10) with the neck 2 held by the neck mold 27 to the injection molding section 21, the temperature adjustment section 22, the blow molding section 23, and the take-out section 24. In addition, the conveying mechanism 26 also has a lifting mechanism (a longitudinal mold opening and closing mechanism), a neck mold opening mechanism, and performs actions such as lifting the transfer plate, closing the mold of the injection molding section 21, and opening the mold (demolding).

[0030] (Injection molding section 21) Injection molding section 21 includes an injection cavity mold and an injection core mold (not shown in the figure), for manufacturing... Figure 1 The preform 1 is shown. An injection device 25 for supplying resin material, which serves as the raw material for the preform 1, is connected to the injection molding section 21.

[0031] In the injection molding section 21, the aforementioned injection cavity mold, injection core mold, and neck mold 27 of the conveying mechanism 26 are closed to form a mold space in the shape of a preform. Then, molten resin material is injected from the injection device 25 into such a preform-shaped mold space, thereby manufacturing the preform 1 using the injection molding section 21.

[0032] Furthermore, when the injection molding section 21 is opened, the neck mold 27 of the conveying mechanism 26 is not opened and the pre-plasticized preform 1 is directly conveyed. The number of pre-plasticized preforms 1 simultaneously molded by 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.

[0033] (Temperature adjustment unit 22) The temperature adjustment unit 22 homogenizes, removes temperature deviations, and adjusts the temperature distribution of the preform 1 conveyed from the injection molding unit 21, adjusting the temperature of the preform 1 to a temperature suitable for final blow molding (e.g., approximately 90°C to 110°C for PET material, and approximately 170°C to 180°C for PC material). In addition, the temperature adjustment unit 22 also cools the preform 1 at its high temperature after injection molding.

[0034] Figure 4 This is a longitudinal sectional view showing a structural example of the temperature adjustment unit 22 in this embodiment. The temperature adjustment unit 22 is a structure composed of a temperature-regulating cavity mold 31 capable of housing the pre-plasticized blank 1, a cooling core (air inlet and outlet core for cooling) 32, and a cylindrical cooling rod 33.

[0035] The temperature-regulating cavity mold 31 is an example of a temperature-adjusting mold, having a space for accommodating the pre-plasticized parison 1 held by the neck mold 17. To accommodate the pre-blow molding process described later, the temperature-regulating cavity mold 31 consists of an upper first portion and a lower second portion. The upper first portion is composed of a pair of parting molds divided along the axial direction (vertical direction), while the lower second portion is not a parting mold. The first and second portions in the closed state form the temperature-adjusting space of the temperature-regulating cavity mold 31.

[0036] The temperature adjustment space of the temperature-regulating cavity mold 31 is formed as a bottomed cylindrical shape with an open top. The inner diameter of the temperature-regulating cavity mold 31 is larger than the outer diameter of the preform, and the axial length of the temperature-regulating cavity mold 31 is set to be approximately the same as the size of the preform 1. Since the parting mold at the upper first part can be opened and closed in the horizontal direction, the preform 1 can be inserted from the top into the temperature-regulating cavity mold 31 and housed, and the expanded preform 1 after preparation for blow molding or cooling blow molding can be pulled out from the top.

[0037] The temperature-regulating cavity mold 31 is composed of, for example, multiple block components 34 stacked in a multi-layered manner along the axial direction of the pre-plasticized blank 1. Figure 4 The illustration shows an example where the temperature-regulating cavity mold 31 is constructed by stacking four layers of block components 34. However, the number of divisions in the temperature-regulating cavity mold 31 is not limited to the above and can be appropriately changed. The uppermost block component 34 constitutes the first part of the temperature-regulating cavity mold 31. The block components 34 located below the uppermost layer constitute the second part of the temperature-regulating cavity mold 31.

[0038] Each component 34 of the temperature-regulating cavity mold 31 has an opening (inner peripheral surface, cavity) 35 on its inner side to form a space for temperature adjustment. Furthermore, each component 34 has a flow path 36 for the flow of a temperature-regulating medium (cooling medium) and multiple ports 37 for the flow of the temperature-regulating medium from the outside to the flow path 36. The temperature of each component 34 is maintained at a given temperature by the temperature-regulating medium flowing inside the mold. Thus, the temperature of the temperature-regulating cavity mold 31 can be adjusted by contacting the outer surface of the housed preform 1. The temperature of the temperature-regulating medium is not particularly limited; for example, when the material of the preform 1 is PET, it is appropriately set in the range of 50°C to 100°C, preferably 60°C to 90°C; when the material is PC, it is appropriately set in the range of 100°C to 200°C, preferably 140°C to 180°C. Additionally, in order to form a desired temperature distribution along the axial direction of the preform 1, the temperature of each component 34 can be adjusted to a different temperature.

[0039] Furthermore, the bottom block member 34A, which is located at the lowest layer of the temperature-regulating cavity mold 31 and faces the bottom 4 of the preform 1, has a heat-insulating member 41 arranged in a ring on a portion of the mold surface of the opening 35. The heat-insulating member 41 of the bottom block member 34A is located at a position opposite to the area in the preform 1 where the grounding portion 13b will be formed (an example of the target area), and has a heat-insulating region formed of a material with a lower thermal conductivity than the material of the block member 34.

[0040] Figure 5 Figures (a) and (b) are structural examples of the base component 34A. The base component 34A is symmetrical from left to right. Figure 5 Only half of the base member 34A is shown in (a) and (b). The base member 34A is composed of an upper part 42 and a lower part 43 that can be divided vertically along the axial direction, and a heat insulation member 41. In the upper part 42 and the lower part 43, cylindrical stepped portions (42a and 43a) are respectively provided on the inner periphery near the dividing surface. The stepped portions 42a and 43a are recessed from the adjacent inner periphery surfaces in the outward diameter direction, and the inner periphery (horizontal inner diameter) of the stepped portions 42a and 43a is larger than the diameter of the mold surface (opening) of the base member 34A. The heat insulation member 41 can be accommodated inside the stepped portions 42a and 43a.

[0041] The heat insulation member 41 is held in the axial direction by the upper part 42 and the lower part 43 and nested in the stepped parts 42a and 43a, and can be replaced relative to the upper part 42 and the lower part 43. In addition, the inner peripheral surface of the heat insulation member 41 is configured to be coplanar with the mold surface of the bottom block member 34A and to contact the outer periphery (outer surface) of the preform 1 after cooling and blow molding.

[0042] Here, the heat insulation member 41 is constructed by stacking multiple annular mold components axially. In this embodiment, an example is shown where three mold components 41a, 41b, and 41c are sequentially combined from the top to form the heat insulation member 41, but the number of mold components constituting the heat insulation member 41 may be more than three. At least one of the multiple mold components 41a, 41b, and 41c is made of a component with low thermal conductivity (e.g., a resin material such as polyetheretherketone (PEEK) or a ceramic such as cordierite). Furthermore, the heat insulation member 41 (or at least one of the multiple annular mold components) preferably has a low thermal conductivity in the range of 0.25 to 8.0 (W / m·K), preferably 0.25 to 3.0 (W / m·K), and more preferably 0.25 to 1.5 (W / m·K).

[0043] The axial lengths of each mold component 41a, 41b, and 41c can be appropriately varied within a range where the axial length of the heat insulation member 41 remains constant. By changing the axial lengths of each mold component 41a, 41b, and 41c, the contact positions between the mold components 41a, 41b, and 41c and the preform 1 can be adjusted. Furthermore, the heat insulation member 41 or each mold component 41a, 41b, and 41c is opposite to the outer peripheral surface (outer surface) of the corresponding area (object portion) of the preform 1 (more specifically, the bottom 4 of the preform 1) forming the grounding portion 13b of the container 10.

[0044] For example, in Figure 5 In (b), with Figure 5 Compared to (a), the axial length of mold component 41a is shorter, and the axial length of mold component 41b is longer. Therefore, in Figure 5 In the bottom block component 34A of (a) and (b), the contact positions of the mold components 41a and 41b with the pre-plasticized blank 1 change respectively.

[0045] That is, when one of the multiple mold components is a component with low thermal conductivity, and the remaining part is composed of components with relatively high thermal conductivity such as the upper part 42 and the lower part 43 (for example, when there are 3 mold components, one or two are components with low thermal conductivity, and the remaining two or one are components with relatively high thermal conductivity), the contact position between the mold component with low thermal conductivity and the preform 1 can be changed.

[0046] For example, in Figure 5 (b) and Figure 5 In embodiment (a), when either mold component 41a or mold component 41b is a component with low thermal conductivity, the position of the portion of the bottom of the preform 1 where high heat retention is desired (the portion where temperature reduction is not desired) can be changed respectively. When mold component 41a is the component with low thermal conductivity, heat retention reduction (temperature reduction) in the upper portion of the bottom 4 of the preform 1 can be suppressed. When mold component 41b is the component with low thermal conductivity, heat retention reduction in the lower portion of the bottom 4 of the preform 1 can be suppressed. Furthermore, as... Figure 5 As shown in (b), when the component with low thermal conductivity is mold component 41b and has a long axial length, heat retention reduction for the wider portion of the bottom 4 of the preform 1 can be suppressed. When the component with low thermal conductivity is mold component 41a and has a short axial length, heat retention reduction for the narrower portion (local portion) of the bottom 4 of the preform 1 can be suppressed.

[0047] Furthermore, the mold components of the heat insulation member 41 can be stacked axially with mold components of the same material, or they can be made of materials with different thermal conductivity. By changing the materials of the mold components 41a, 41b, and 41c, the cooling intensity of the mold components 41a, 41b, and 41c on the preform 1 can be adjusted. In addition, any one of the mold components can also be a spacer made of the same material as the block member 34 and arranged to adjust the position of the heat insulation material. The mold component that serves as the spacer is preferably made of a component having the same thermal conductivity as the upper layer 42 and the lower layer 43.

[0048] Here, if the thermal conductivity of mold components 41a, 41b, and 41c is high, the heat of the preform 1 is easily transferred to mold components 41a, 41b, and 41c. In the above case, at the contact points of mold components 41a, 41b, and 41c, the heat retention of the preform 1 is reduced, making it difficult to stretch during blow molding, and the wall thickness in the container 10 tends to increase.

[0049] On the other hand, if the thermal conductivity of mold components 41a, 41b, and 41c is low, the heat of the preform 1 is difficult to transfer to the mold components 41a, 41b, and 41c. In the above case, the heat retention of the preform 1 is difficult to reduce at the contact points of mold components 41a, 41b, and 41c, and it is easy to stretch during blow molding. Therefore, the wall thickness in the container 10 is easy to become thinner.

[0050] In this embodiment, the temperature distribution of the pre-plasticized blank 1 relative to the area where the grounding portion 13b is formed is adjusted by using the combination of mold components 41a, 41b, and 41c.

[0051] In addition, to facilitate demolding of the preform 1 from the mold surface, an air inlet 44 is provided in the bottom block member 34A. The air inlet 44 is disposed between the upper part 42 and the lower part 43, and sprays compressed air toward the opening 35 of the bottom block member 34A. Furthermore, the compressed air sprayed from the air inlet 44 is introduced into the opening 35 through the gap between the upper part 42 and the lower part 43, for example, through the slit 44a formed in the heat insulation member 41, and sprayed onto the preform 1.

[0052] return Figure 4 The cooling core 32 is a cylindrical mold inserted into the inner side of the neck mold 27. Cooling rods 33 are concentrically arranged inside the cooling core 32, spaced annularly. When inserted into the neck mold 27, the cooling core 32 is in close contact with the inner circumference or upper end face of the neck 2 of the preform 1, maintaining an airtight seal. Furthermore, the inner side of the cooling rods 33 and the gap between the cooling rods 33 and the cooling core 32 respectively constitute the compressed air supply path and exhaust path. Figure 4The diagram shows an example where the inner side of the cooling rod 33 is connected to the compressed air supply path, and the gap between the cooling rod 33 and the cooling core 32 is connected to the compressed air exhaust path. However, the compressed air supply path and exhaust path can also be in the opposite relationship. As described above, the temperature adjustment unit 22 can cool the preform 1 by blowing compressed air into it, through cooling based on compressed air and heat exchange based on contact with the temperature-regulating cavity mold 31.

[0053] When compressed air is introduced into the preform 1 using the temperature adjustment unit 22, pre-blow molding of the preform 1 is performed using the temperature adjustment unit 22 before blow molding to form an intermediate molded body (not shown) with an enlarged main body compared to the preform 1. Then, compressed air is introduced into the intermediate molded body for cooling blow molding. Furthermore, the cooling rod 33 can also be a concentric, multi-tubular (e.g., double-tubular, triple-tubular) structure, and the compressed air ejection position can be set at the main body 3 of the preform 1.

[0054] (Blow Molding Section 23) The blow molding section 23 stretches and blow molds the preform 1 (intermediate molded body) whose temperature has been adjusted by the temperature adjustment section 22 to manufacture a container.

[0055] The blow molding section 23 has a pair of parting dies corresponding to the shape of the container, namely a blow molding cavity mold, a bottom mold, a stretching rod, and an air inlet / outlet component (all not shown). The blow molding section 23 performs blow molding while stretching the pre-plasticized preform 1. As a result, the pre-plasticized preform 1 is shaped into the shape of the blow molding cavity mold, thereby enabling the manufacture of the container 10.

[0056] (Removal section 24) The removal section 24 is configured to release the neck 2 of the container 10 manufactured by the blow molding section 23 from the neck mold 27 and remove the container 10 to the outside of the blow molding apparatus 20.

[0057] <Description of the manufacturing method of the container> Next, the method for manufacturing a container using the blow molding apparatus 20 of this embodiment will be described. Figure 6 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.

[0058] (Step S100: Mold adjustment process) The mold adjustment process is a preparation process for adjusting the combination of mold components 41a, 41b, and 41c of the heat insulation component 41 of the bottom block component 34A according to the specifications of the blow-molded container 10.

[0059] Specifically, in the heat insulation member 41, the combination of mold members 41a, 41b, and 41c is adjusted according to the specifications of the blow-molded container 10, such that the thermal conductivity of the mold member opposite to the area of ​​the preform 1 where the grounding portion 13b will be formed is relatively lower. Alternatively, in order to adjust the cooling intensity of the preform 1, mold members 41a, 41b, and 41c can be changed to mold members made of materials with different thermal conductivity.

[0060] If the above mold adjustment process is completed, then proceed with the various processes of the container manufacturing cycle as shown below.

[0061] (Step S101: Injection molding process) First, 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 1. Then, after the injection (filling and holding pressure) of the resin material is completed, or after the minimum cooling time set after the injection is completed, the injection mold of the injection molding section 21 is opened.

[0062] 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.

[0063] 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 (cooling time) after the injection molding section 21 completes the injection of the resin material (including the speed-controlled filling process and the pressure-controlled holding process) 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 aforementioned cooling time relative to the injection time can be set even shorter. For example, the cooling time relative to the injection time of the resin material is more preferably less than 2 / 5, further preferably less than 1 / 4, and particularly preferably less than 1 / 5.

[0064] 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 to be thinner, and the core layer (the inner layer in a softened or molten state) is formed to be 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 retains high heat at high temperatures.

[0065] If the injection molding of the preform 1 is completed, the mold of the injection molding section 21 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 26 moves by rotating a given angle, and the preform 1 held in the neck mold 27 is conveyed to the temperature adjustment section 22 in a state of heat retention during injection molding.

[0066] (Step S102: Temperature adjustment process) Next, in the temperature adjustment unit 22, temperature adjustment is performed to bring the temperature of the preform 1 close to the temperature suitable for final blow molding.

[0067] In the temperature adjustment process, the preform 1 held in the neck mold 27 is placed into the temperature-regulating cavity mold 31 by the descent of the transfer plate, and the cooling core 32 and cooling rod 33 are inserted into the preform 1. Then, after preparing the blow-molded preform 1, compressed air is introduced into the intermediate molding body to perform cooling blow molding.

[0068] In the cooling blow molding process of the temperature adjustment step, the preform 1 is cooled by internal cooling based on compressed air and by heat exchange based on contact with the temperature-adjusting cavity mold 31. Furthermore, in the bottom block member 34A of the temperature-adjusting cavity mold 31, the area of ​​the preform 1 where the grounding portion 13b will be formed contacts the mold components 41a, 41b, and 41c of the heat insulation member 41. Thus, the area of ​​the preform 1 where the grounding portion 13b will be formed is temperature-adjusted to a state where its heat is relatively higher than other parts. Moreover, since the above-mentioned temperature adjustment is performed simultaneously during pre-blow molding and cooling blow molding, the blow molding cycle time is not prolonged, which also helps to shorten the blow molding cycle. Furthermore, since the mold components 41a, 41b, and 41c of the heat insulation member 41 can be manufactured at a lower cost, the manufacturing cost of the mold can also be reduced.

[0069] When the blow molding process in the temperature adjustment section 22 is completed, the temperature-adjusting cavity mold 31 opens, and air is introduced from the air inlet section 44 of the bottom block member 34A, causing the pre-plasticized blank 1 to be demolded from the mold surface of the temperature-adjusting cavity mold 31. By introducing air from the air inlet section 44, deformation during demolding caused by the pre-plasticized blank 1 sticking to the mold can be suppressed.

[0070] Subsequently, the transfer plate of the conveying mechanism 26 moves by rotating a given angle, and the pre-plasticized preform 1, which has been kept in the neck mold 27 after temperature adjustment, is conveyed to the blow molding section 23.

[0071] (Step S103: Blow molding process) Next, in the blow molding section 23, the container 10 is blow molded.

[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. Then, a tension rod (longitudinal tensioning component) is lowered, pressing against the bottom 4 of the preform 1 from its inner surface. Longitudinal tension is applied as needed, and transverse tension is applied by supplying blow molding air through the air inlet / outlet component. Thus, the preform 1 bulges out and is shaped to fit tightly against the mold space of the blow molding cavity mold, and is blow molded into a container 10. Furthermore, 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, rapidly rise to the forming position before or after mold closing, and descend to a standby position after blow molding, before or after mold opening.

[0073] Here, in this embodiment, the area of ​​the preform 1 where the grounding portion 13b is to be formed is temperature-adjusted through a temperature adjustment process (S102) to achieve a state where the heat retention is relatively higher than that of other parts. Therefore, in the blow molding process, the area where the grounding portion 13b is formed in the preform 1 (more specifically, the bottom 4 of the preform 1) is more easily stretched than other areas. That is, in the blow-molded container 10, the thickness of the grounding portion 13b becomes thinner, and through horizontal axis stretching, the thickness of the heel portion 13a located on the outer periphery of the grounding portion 13b correspondingly becomes thicker. Therefore, in this embodiment, a large container with a preferred wall thickness distribution, in which the thickness of the grounding portion 13b is thinner and the thickness of the heel portion 13a is thicker, can be obtained.

[0074] (Step S104: Container removal process) Once blow molding is complete, the blow molding cavity is opened. This allows the container to move from the blow molding section 13.

[0075] Next, the transfer plate of the conveying mechanism 26 moves by a given angle, and the container 10 is conveyed to the take-out section 24. In the take-out section 24, the neck 2 of the container 10 is released from the neck mold 27, and the container 10 is taken out of the blow molding apparatus 20.

[0076] The above completes one container manufacturing cycle in the container manufacturing method. Afterwards, by moving the transfer plate of the conveying mechanism 26 by a given angle, the processes S101 to S104 described above are repeated. Furthermore, while the blow molding apparatus 20 is operating, the manufacturing of four batches of containers 10, each with a time difference of one process, is performed in parallel.

[0077] Furthermore, in the structure of the blow molding apparatus 20, 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.

[0078] 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.

[0079] Furthermore, the embodiments disclosed herein are illustrative in all respects and should not be considered restrictive. The scope of the invention is defined not by the foregoing description but by the scope of the patent claims, and is intended to include the meaning equivalent to the scope of the patent claims and all modifications within that scope.

[0080] Symbol Explanation 1: Preform; 2: Neck; 3: Main body; 4: Bottom; 10: Container; 11: Shoulder; 12: Main body; 13: Bottom; 13a: Heel; 13b: Grounding part; 13c: Upper bottom; 20: Blow molding device; 21: Injection molding part; 22: Temperature adjustment part; 23: Blow molding part; 24: Take-out part; 25: Injection device; 26: Conveying mechanism; 27: Neck mold; 31: Temperature-regulating cavity mold; 32: Cooling core; 33: Cooling rod; 34: Block component; 34A: Bottom block component; 35: Opening; 36: Flow path; 37: Port; 41: Heat insulation component; 41a, 41b, 41c: Mold components; 42: Upper layer; 42a: Stepped part; 43: Lower layer; 43a: Stepped part; 44: Air inlet; 44a: Slit.

Claims

1. A temperature-adjusting mold for adjusting the temperature of a bottomed cylindrical preform used in blow molding for a resin container, the temperature-adjusting mold comprising: A cavity mold that houses the preform inside and contacts the outer surface of the preform; and A cooling mold is inserted into the pre-plasticized preform, and compressed air is introduced into the pre-plasticized preform for cooling. The cavity mold can accommodate an annular heat-insulating member in a replaceable manner. The heat-insulating member has an insulating region with a lower thermal conductivity than the cavity mold. The heat insulation component is disposed on the outer periphery of the target portion of the preform corresponding to the grounding portion of the container, and abuts against the target portion to adjust the temperature of the target portion to a higher temperature than other portions.

2. The temperature adjustment mold according to claim 1, wherein, The heat insulation component includes a first mold component and a second mold component, which are respectively formed in annular shape and have different thermal conductivity. The heat insulation component is formed by stacking the first mold component and the second mold component along the axial direction.

3. The temperature adjustment mold according to claim 2, wherein, The first mold component and the second mold component can be replaced with components with different axial dimensions.

4. The temperature adjustment mold according to claim 1, wherein, The cavity mold has an air inlet section that sprays compressed air onto the outer periphery of the pre-plasticized blank, causing the pre-plasticized blank to be demolded from the cavity mold.

5. An apparatus for manufacturing a resin container, comprising: The injection molding section performs injection molding on a resin-made bottomed cylindrical preform. A temperature adjustment unit that adjusts the temperature of the preform after injection molding; and The blow molding section blow molds the pre-plasticized preform after temperature adjustment while it is still heated, as included in injection molding, to manufacture resin containers. The temperature adjustment unit includes a temperature adjustment mold according to any one of claims 1 to 4, which causes the heat insulation member to abut against the target portion of the pre-plasticized blank corresponding to the ground portion of the container, thereby adjusting the temperature of the target portion to a higher temperature than other portions.

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. A method for manufacturing a resin container, comprising: The injection molding process involves injection molding a resin-made, bottomed, cylindrical preform. The temperature adjustment process involves adjusting the temperature of the preform after injection molding; and The blow molding process involves blow molding a pre-plasticized preform, after temperature adjustment, while it is still heated as in injection molding, to manufacture resin containers. In the temperature adjustment process, the temperature adjustment mold according to any one of claims 1 to 4 is used to bring the heat insulation member against the target part of the pre-plasticized blank corresponding to the ground part of the container, and adjust the temperature of the target part to a higher temperature than other parts.

8. The method for manufacturing a resin container according to claim 7, wherein, The method for manufacturing the resin container further includes a mold adjustment step for adjusting the position and thermal conductivity of the heat-insulating region in the heat-insulating component. After the mold adjustment process, the injection molding process, the temperature adjustment process, and the blow molding process are performed.

9. The method for manufacturing a resin container according to claim 7, 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.

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