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

Abstract

This temperature adjustment mold for adjusting the temperature of a bottomed cylindrical preform made of a resin comprises a rod member including: a cylindrical rod body that is inserted into the preform and extends in the axial direction of the preform; and a tip member that is attached to the tip side of the rod body and comes into contact with the bottom inner circumferential surface of the preform. The tip member comprises an air intake hole communicating with an internal space of the rod body. The rod member suctions air from the air intake hole via the rod body, thereby causing the bottom inner circumferential surface of the preform to be suctioned onto the tip member and supported.

Description

Mold for Temperature Adjustment, Manufacturing Apparatus and Manufacturing Method for Resin Container

[0001] The present invention relates to a mold for temperature adjustment, a manufacturing apparatus, and a manufacturing method for a resin container.

[0002] Conventionally, as one of the manufacturing apparatuses for resin containers, a hot parison type blow molding apparatus is known. The hot parison type blow molding apparatus is configured to blow-mold a resin container using the retained heat during injection molding of a preform, and is advantageous in that it can manufacture resin containers that are diverse and have an excellent aesthetic appearance as compared with the cold parison type.

[0003] Generally, a preform immediately after injection molding has a high retained heat and is likely to deform. Also, depending on the type of resin material used for the container and the specifications of the container to be blow-molded, it is necessary to adjust the temperature of the preform before blow molding to a high temperature. Therefore, in the heating process, temperature adjustment process, etc. of the container manufacturing cycle, the preform may deform and sag due to its own weight, resulting in drawdown.

[0004] For example, when the container to be blow-molded is large, the preform also becomes large and heavy, so drawdown of the preform is more likely to occur. Also, for example, in the molding of a hollow handle container, it is necessary to adjust the preform to a higher temperature, and drawdown of the preform is likely to occur.

[0005] When the preform undergoes drawdown, it becomes impossible to shape the preform into a container having an appropriate wall thickness distribution and appearance in the blow molding process, and the molding of the container becomes unstable. Also, when the drawn-down resin contacts the mold, it becomes necessary to stop the container manufacturing cycle, which may hinder the manufacture of the container. For example, Patent Documents 1 and 2 disclose a configuration in which a support member for supporting the lower end of the preform is provided in a blow molding machine, and the preform is lowered together with the support member to suppress blowdown in the blow molding process.

[0006] Japanese Patent No. 2798160, Japanese Patent No. 3677741

[0007] However, while Patent Documents 1 and 2 can address the blowdown of preforms in the blow molding process, they have difficulty adequately addressing the blowdown of preforms in the temperature control process, which adjusts the temperature of the preform before blow molding.

[0008] Therefore, the present invention has been made in view of these problems, and aims to provide a temperature control mold that can appropriately handle the blowdown of the preform in the temperature control process, which adjusts the temperature of the preform before blow molding.

[0009] One aspect of the present invention is a temperature-regulating mold for regulating the temperature of a bottomed cylindrical preform made of resin. The temperature-regulating mold comprises a rod member having a cylindrical rod body inserted into the preform and extending in the axial direction of the preform, and a tip member attached to the tip side of the rod body and in contact with the inner circumferential surface of the bottom of the preform. The tip member has an air intake hole that communicates with the internal space of the rod body. The rod member supports the inner circumferential surface of the bottom of the preform by drawing air in through the air intake hole via the rod body, thereby adhering to and supporting the tip member.

[0010] According to one aspect of the present invention, a temperature control mold is provided that can appropriately handle the blowdown of a preform during a temperature control process in which the temperature of the preform is adjusted before blow molding.

[0011] This is a schematic diagram showing the configuration of the blow molding apparatus of this embodiment. This is a longitudinal cross-sectional view showing an example of the configuration of the temperature control section of this embodiment. (a) is an enlarged view of the longitudinal cross-section of the tip piece, and (b) is a view of the tip piece from the bottom side. This is a perspective view showing an example of the configuration of the rod member of this embodiment. This is a diagram showing the state in which a spacer member is partially attached in the circumferential direction of the rod body. This is a flowchart showing the process of the container manufacturing method. This is a longitudinal cross-sectional view showing a modified example of the temperature control section of this embodiment.

[0012] Embodiments of the present invention will be described below with reference to the drawings. In the embodiments, for the sake of clarity, structures and elements other than the main parts of the present invention will be simplified or omitted in the description. Also, the same elements will be denoted by the same reference numerals in the drawings. Note that the shapes and dimensions of each element shown in the drawings are schematic representations and do not represent the actual shapes and dimensions.

[0013] Figure 1 is a schematic diagram showing the configuration of the blow molding apparatus 10 of this embodiment, which is applied to 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 and employs a hot parison method (also referred to as a one-stage method) in which the container is blow-molded by utilizing the heat retained during injection molding (internal heat quantity) without cooling the preform 1 (not shown in Figure 1) to room temperature.

[0014] The blow molding apparatus 10 comprises an injection molding unit 11, a temperature control unit 12, a blow molding unit 13, a removal unit 14, and a transport mechanism 16. The injection molding unit 11, the temperature control unit 12, the blow molding unit 13, and the removal unit 14 are positioned at predetermined angles (for example, 90 degrees) around the transport mechanism 16.

[0015] (Transport mechanism 16) The transport mechanism 16 includes a transport plate (not shown) that moves in a rotational direction about an axis perpendicular to the plane of the paper in Figure 1. The transport plate is composed of a single disc-shaped flat plate member or a plurality of substantially fan-shaped flat plate members divided for each molding station. One or more neck-shaped members 17 (not shown in Figure 1) for holding the neck portion 2 of the preform 1 (or the neck portion of the container) are arranged on the transport plate at predetermined angles.

[0016] The transport mechanism 16, equipped with a rotating mechanism (not shown), moves a transport plate to transport the preform 1 (or container) whose neck portion 2 is held by the neck mold 17, in the order of injection molding section 11, temperature control section 12, blow molding section 13, and removal section 14. The transport mechanism 16 is further equipped with a lifting mechanism (vertical mold opening and closing mechanism) and a mold opening mechanism for the neck mold, and also performs operations related to lifting and lowering the transport plate, as well as mold closing and mold opening (release) in the injection molding section 11, etc.

[0017] (Injection Molding Section 11) The injection molding section 11 includes an injection cavity mold and an injection core mold, which are not shown in the illustration, and manufactures the preform 1 shown in Figure 2, which will be described later. An injection device 15 is connected to the injection molding section 11 to supply the resin material, which is the raw material for the preform 1.

[0018] In the injection molding section 11, the injection cavity mold, injection core mold, and the neck mold 17 of the transport mechanism 16 are closed to form a mold space in the shape of a preform. Then, molten resin material is injected from the injection device 15 into this preform-shaped mold space, thereby manufacturing the preform 1 in the injection molding section 11.

[0019] Here, the overall shape of the preform 1 is a bottomed cylindrical shape with one end open and the other end closed. As shown in Figure 2, which will be described later, the preform 1 has a neck portion 2 formed at one end and having an opening, a body portion 3 connected to the neck portion 2 and formed in a cylindrical shape, and a bottom portion 4 connected to the body portion 3 and closing the other end.

[0020] Furthermore, the materials for the container and preform 1 are thermoplastic synthetic resins, which can be appropriately selected depending on the application of the container. Specific examples of materials include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexanedimethylene terephthalate), Tritan (Tritan®: a polyester copolymer using cyclobutanediol monomers, manufactured by Eastman Chemical), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPSU (polyphenylsulfone), PS (polystyrene), COP / COC (cyclic olefin polymer), PMMA (polymethyl methacrylate: acrylic), and PLA (polylactic acid).

[0021] While not particularly limited, the preform 1 in this embodiment corresponds to the manufacture of a hollow handle container having, for example, an opening (through hole) or recess on the inner diameter side of the container that functions as a gripping part, but the shape of the container manufactured from the preform 1 is not particularly limited. Furthermore, the material of the preform 1 in this embodiment may be, for example, PET, Tritan, PE, PC, PP, COC, biodegradable resin, etc.

[0022] Furthermore, even when the mold of the injection molding unit 11 is opened, the neck mold 17 of the transport mechanism 16 remains closed and continues to hold and transport the preform 1. The number of preforms 1 that are simultaneously molded in the injection molding unit 11 (i.e., the number of containers that can be simultaneously molded in the blow molding apparatus 10) can be set as appropriate.

[0023] (Temperature control unit 12) The temperature control unit 12 is responsible for equalizing the temperature of the preform 1 transported from the injection molding unit 11, removing uneven temperature distribution, and adjusting the temperature of the preform 1 to a temperature suitable for the final blowing.

[0024] Figure 2 is a longitudinal cross-sectional view showing an example of the configuration of the temperature control unit 12 in this embodiment. The temperature control unit 12 comprises a temperature control cavity type (heating pot type) 21 capable of housing the preform 1, and a rod member 22 inserted into the interior of the preform 1.

[0025] The temperature-controlled cavity mold 21 is an example of an element of a temperature-controlled mold, and is a mold having a temperature-controlled space capable of accommodating the preform 1 held in the neck mold 17. The temperature-controlled space is open at the top and is formed in a bottomed cylindrical shape corresponding to the shape of the preform 1. The inner diameter of the space in the temperature-controlled cavity mold 21 is larger than the outer diameter of the preform 1, and the axial length of the space in the temperature-controlled cavity mold 21 is set to be longer than the length of the preform 1. As a result, the preform 1 can be inserted into the space in the temperature-controlled cavity mold 21 from the top and accommodated without the preform 1 coming into contact with the inner surface of the temperature-controlled cavity mold 21.

[0026] The temperature-controlled cavity type 21 is, for example, a heating pot type that is provided in one or more stages in the axial direction of the preform 1 and heats the preform 1 without contact. Preferably, the temperature-controlled cavity type 21 is composed of block members stacked in multiple stages (for example, 8 stages) in the axial direction of the preform 1. Each block member is fitted with a heating element (not shown), such as a band heater. The temperature of each block member is maintained at a predetermined temperature by the heating element, and the body 3 and bottom 4 of the contained preform 1 can be heated without contact by radiant heat. The temperature of the heating element is appropriately set in a range of, for example, between 200°C and 400°C.

[0027] The rod member 22 is an example of an element of the temperature control mold, and is a shaft-shaped member whose tip is inserted into the inside of the preform 1 in the temperature control section 12. The axial length of the portion of the rod member 22 that is inserted into the preform 1 corresponds to the length from the body 2 to the bottom 3 of the preform 1 housed in the temperature control cavity mold 21 (for example, the same as, or slightly shorter than, the axial length of the inner circumference from the body 2 to the bottom 3 of the preform 1).

[0028] The rod member 22 is positioned to move back and forth relative to the neck mold 17 that holds the preform 1 in the temperature control unit 12. Figure 2 shows the state in which the rod member 22 has moved downward in the figure and is inserted into the neck mold 17 and the preform 1.

[0029] The rod member 22 comprises at least a rod body 24, a tip piece 25, and a spacer member 26. The rod member 22 may further have a core portion (rod base end) 23 surrounding the rod member 22 above the tip piece 25.

[0030] The core portion 23 is a cylindrical part provided at the base end (upper side) of the rod member 22, and has a tapered outer shape that narrows in diameter towards the tip. The shape of the tip of the core portion 23 corresponds to the inner circumference shape of the neck mold 17, and the rod body 24 is attached to the tip of the core portion 23. The core portion 23 is inserted into the neck mold 17 when the rod member 22 descends, and serves to guide the descending rod member 22 and position the rod body 24 relative to the preform 1.

[0031] The rod body 24 is a hollow cylindrical mold member formed from a highly heat-conductive mold material such as carbon steel or stainless steel. The rod body 24 extends along the axial direction of the preform 1, penetrating the inner circumference of the core portion 23. Although not particularly limited, the portion of the rod body 24 inserted into the preform 1 may be formed as a columnar body with a cross-sectional shape perpendicular to the axial direction that is a regular polygon (for example, a regular hexagonal cross-section), as shown in Figure 4 described later.

[0032] As shown in Figure 2, the outer diameter of the rod body 24 is formed to be smaller than the inner diameter of the preform 1. This allows the rod body 24 to be positioned inside the preform 1 with a gap between it and the inner circumferential surface of the preform 1 in a cross section perpendicular to the axial direction.

[0033] Furthermore, the internal space of the rod body 24 is connected to an intake mechanism (exhaust pump, etc. (not shown)) at the base end, which is located above the core portion 23. By driving (starting) the intake mechanism, an airflow can be formed inside the rod body 24 from the tip side to the base end side of the rod member 22.

[0034] Figure 3(a) is an enlarged view of the longitudinal cross-section of the tip piece 25, and Figure 3(b) is a view of the tip piece 25 from the bottom side. The tip piece 25 is an example of a tip member, which is attached to the tip side (lower end side) of the rod body 24 and is a member that can come into contact with the bottom 4 of the preform 1. The tip piece 25 in Figure 2 is formed in a bottomed cylindrical shape and is inserted into the tip side of the rod body 24 and connected.

[0035] The tip surface 25a of the tip piece 25 faces the bottom surface of the preform 1. The tip surface 25a of the tip piece 25 is formed in a curved shape corresponding to the bottom surface on the inner circumference of the preform 1. In addition, an intake hole 25b is formed on the tip surface 25a of the tip piece 25, which penetrates the tip piece 25 axially and communicates with the internal space of the rod body 24.

[0036] When the intake mechanism connected to the rod member 22 is driven (started), air is drawn into the rod body 24 from the intake hole 25b of the tip piece 25 at the bottom 4 of the preform 1. This creates a negative pressure between the bottom 4 of the preform 1 and the tip piece 25, causing the bottom 4 of the preform 1 to move upward toward the tip piece 25. As a result, the intake hole 25b of the tip piece 25 is blocked by the bottom 4 of the preform 1, and the bottom 4 of the preform 1 comes into contact with the tip surface 25a of the tip piece 25 and is attracted (suctioned), and the bottom 4 of the preform 1 is supported from the inside by the rod member 22. Alternatively, after bringing the tip piece 25 into contact with the inner surface of the bottom 4 of the preform 1, the intake mechanism may be started to create a negative pressure between the bottom 4 and the tip piece 25, causing the preform 1 to be attracted (suctioned) toward the tip piece 25. The negative pressure of the air supply mechanism (the pressure that sucks the bottom 4 of the preform 1) is set to a pressure that does not cause deformation of the bottom 4 while the preform 1 is being held in place by suction (for example, 0.05 MPa to 0.1 MPa). After the temperature of the preform 1 reaches a temperature suitable for blow molding, the air supply mechanism is stopped, and the negative pressure between the bottom 4 and the tip piece 25 is released, thereby releasing the support of the bottom 4 of the preform 1 by the rod member 22.

[0037] As described above, the rod member 22 can support the bottom 4 of the preform 1 by adsorption (suction). Since the inner circumferential surface of the bottom 4 of the preform 1 is adsorbed (suctioned) by the rod member 22 and supported from above, the outer circumferential surface of the bottom 4 of the preform 1 faces the bottom of the temperature-controlled cavity type 21 with a gap between them.

[0038] As an example, the shape of the tip surface 25a and the intake hole 25b of the tip piece 25 are preferably formed as follows. As shown in Figures 3(a) and (b), a counterbore-like, shallow recess 25c is formed in the central part of the tip surface 25a of the tip piece 25. In addition, one intake hole 25b is formed concentrically with the recess 25c, penetrating the tip piece 25 axially and communicating with the internal space of the rod body 24. As shown in Figure 3(a), the shape of the recess 25c and the intake hole 25b are circular when viewed from below. The inner diameter of the intake hole 25b is formed to be smaller than the inner diameter of the recess 25c. A step is formed between the recess 25c and the intake hole 25b of the tip piece 25, connecting them radially.

[0039] While not particularly limited, the axial dimension (depth) of the recess 25c is approximately 0.5 mm to 2.0 mm, preferably 0.7 mm to 1.2 mm. The axial dimension (depth) of the recess 25c may also be 1 / 40 to 1 / 20 of the diameter of the tip piece 25. The inner diameter of the intake hole 25b is approximately 0.5 mm to 10 mm, preferably 1 mm to 3 mm. The inner diameter of the intake hole 25b may also be approximately 1 / 5 to 1 / 20 of the diameter of the tip piece 25. Furthermore, the radial dimension (diameter) of the recess 25c is approximately 5 mm to 30 mm, preferably 7 mm to 12 mm. The radial dimension of the recess 25c may also be approximately 1 / 5 to 4 / 5 of the diameter of the tip piece 25. The ratio of the inner diameter of the intake hole 25b to the radial dimension (diameter) of the recess 25c may be approximately 1 / 10 to 1 / 3.

[0040] For example, in a structure in which multiple air intake holes 25b are formed in the tip piece 25, a drawdown may occur as the suction force of the preform 1 by the tip piece 25 gradually decreases while the preform 1 is being heated in the heating pot. This is presumed to be because when the preform 1 is heated by the heat of the temperature-controlled cavity type 21, the bottom becomes hot and gradually deforms, causing some of the air intake holes 25b to separate from the inner surface of the bottom of the preform 1, gradually reducing the sealing performance and thus decreasing the suction force. Furthermore, in a structure in which multiple air intake holes 25b are formed in the tip piece 25, if the diameter of the air intake holes 25b becomes large, multiple convex transfer marks corresponding to the air intake holes 25b may be formed on the inner surface of the bottom of the preform 1 or the container because the preform 1 is soft at high temperatures.

[0041] Furthermore, if the intake hole 25b of the tip piece 25 is made into a single through-hole, and a bush member having multiple fine vent holes (air supply holes) is provided at the tip of the intake hole 25b, the formation of the above-mentioned transfer marks can be suppressed. However, in the case of the structure with the above-mentioned bush member, cleaning of the bush member becomes complicated, and the cost increases due to the bush member. Moreover, if the tip surface 25a of the tip piece 25 is flush, the bottom of the preform 1 is more likely to stick to the tip piece 25 when the suction of the preform 1 is released.

[0042] On the other hand, in the case of the tip piece 25 shown in Figures 3(a) and 3(b), by making it a single air intake hole 25b, the sealing performance between the preform 1 and the tip piece 25 during heating in the heating pot is less likely to decrease compared to the case where multiple air intake holes are formed. Therefore, with the tip piece 25 shown in Figures 3(a) and 3(b), sufficient suction force of the preform 1 can be maintained during heating in the heating pot, and the drawdown of the preform 1 during heating can be more easily suppressed. In addition, with the tip piece 25 shown in Figures 3(a) and 3(b), the occurrence of multiple convex transfer marks on the preform 1 and container, as occurs when multiple air intake holes are formed, can also be suppressed. Furthermore, with the tip piece 25 shown in Figures 3(a) and 3(b), even if a transfer mark corresponding to the air intake hole 25b occurs in the center of the bottom of the preform 1, the transfer mark will be pressed down by the tip of the stretching rod during blow molding and will become less noticeable, so the aesthetic appearance of the container will not be affected. Furthermore, in the case of the tip piece 25 shown in Figures 3(a) and 3(b), the recess 25c formed on the tip side of the single-hole intake hole 25b prevents the bottom of the preform 1 from sticking to the tip piece 25 when the suction of the preform 1 is released.

[0043] The material of the tip piece 25 is not particularly limited, and the tip piece 25 may be made of, for example, aluminum. Furthermore, the tip piece 25 may be made of a material with higher thermal insulation properties than the rod body 24 in order to suppress excessive heat conduction from the rod body 24 to the bottom 4 of the preform 1. For example, the tip piece 25 may be made of a resin material or ceramic, each with excellent thermal insulation and heat resistance. When the tip piece 25 is made of a material with higher thermal insulation properties than the rod body 24, the risk of excessive cooling of the inner circumference of the bottom 4 of the preform 1 due to contact with the tip piece 25 can be suppressed. In addition, to prevent the bottom of the preform 1 from sticking to the tip piece 25, the tip surface 25a of the tip piece 25 may be formed to a predetermined or higher surface roughness by Yepco treatment or the like.

[0044] The spacer member 26 is one or more detachably attached to any surface (circumferential surface portion 24b) of the outer periphery of the rod body 24, and is a mold piece that partially covers the outer periphery of the rod body 24. The spacer member 26 is attached to an arbitrary region of the circumferential surface of the rod body 24, and is fixed to the rod body 24 by, for example, a bolt (connecting member) 28 that is screwed into the bolt hole 24a of the rod body 24.

[0045] The spacer member 26 functions to adjust the radial interval between the preform 1 and the rod body 24 and to realize a desired temperature distribution of the preform 1. More specifically, the rod body 24 and the spacer member 26 of the present embodiment are relatively lower in temperature than the preform 1, and receive radiant heat from the body portion 3 of the preform 1, and function to lower the temperature on the inner peripheral side of the body portion 3 of the preform 1 (lower the temperature of the body portion 3 of the preform 1 from the inner peripheral surface side). Thereby, it is possible to suppress an excessive increase in temperature of the body portion 3 of the preform 1 and to impart a desired temperature distribution to the body portion 3 of the preform 1. Note that the rod body 24 may be cooled, for example, by the flow of air inside the rod body 24.

[0046] The spacer member 26 is formed of a mold material having high heat conductivity such as carbon steel or stainless steel, for example, in the same manner as the rod body 24, and is in a state of being thermally connected to the rod body 24 when attached to the rod body 24. Note that the spacer member 26 may be formed of the same material as the rod body 24 or may be formed of a different material.

[0047] As an example, each spacer member 26 has a curved surface on the outer peripheral side facing the preform 1 formed following the inner peripheral surface of the preform 1, and a flat surface on the inner peripheral side facing the rod body 24. Each spacer member 26 can cover a range of 1 / the number of circumferential directions of the circumferential surface portion 24b (that is, 1 / the number of faces of the regular polygon of the rod body 24) on the inner periphery of the preform 1. For example, when the cross section of the rod body 24 is a regular hexagon, the spacer member 26 is a strip-shaped piece having an arc shape of a sixth of a circle, and each spacer member 26 covers a range of 1 / 6 of the inner periphery of the preform 1.

[0048] Further, the maximum thickness in the radial direction of the spacer member 26 is set to be smaller than the interval between the surface of the rod body 24 and the inner circumference of the preform 1. Thereby, in a state where the spacer member 26 is attached, a gap is generated between the spacer member 26 and the inner circumference of the preform 1. Therefore, in a state where the spacer member 26 is attached, the rod member 22 receives radiant heat from the inner circumference of the body portion 3 of the preform 1 and absorbs heat, and can reduce the temperature of the inner circumference of the body portion 3 of the preform 1 in a non-contact manner (that is, the rod member 22 can reduce the temperature of the body portion 3 of the preform 1 from the inner circumference side in a non-contact manner).

[0049] In the portion of the rod member 22 of the present embodiment inserted into the preform 1, one or more, preferably a plurality of attachment portions of the spacer member 26 are provided in the axial direction on each surface (each circumferential surface portion 24b) of the columnar body of the rod body 24. For example, as shown in FIGS. 2 and 4, four attachment portions of the spacer member 26 are provided in the axial direction on each surface of the columnar body of the rod body 24. Therefore, the spacer member 26 can be attached to any attachment portion arranged in the circumferential direction and the axial direction of the rod body 24.

[0050] FIG. 5 shows a state in which the spacer member 26 is partially attached in the circumferential direction of the rod body 24 having a regular hexagonal cross section. In FIG. 5, an example in which two spacer members 26 are arranged in the circumferential direction and attached to the rod body 24 is shown, and the spacer member 26 partially covers 1 / 3 of the outer circumference of the rod body 24. For simplicity, the illustration of the temperature control cavity mold 21 is omitted in FIG. 5.

[0051] As shown in FIG. 5, in the preform 1 into which the spacer member 26 is inserted, in the first region in the circumferential direction (the region surrounded by the broken line in FIG. 5) where the spacer member 26 is attached, the radial gap S1 between the inner circumferential surface of the preform 1 and the mold becomes narrow due to the spacer member 26. In the above-described first region, radiant heat from the preform 1 easily reaches the spacer member 26, so the amount of heat absorption increases, and the temperature on the inner circumferential side of the preform 1 easily decreases (that is, the temperature of the body portion 3 of the preform 1 easily decreases).

[0052] On the other hand, in the second circumferential region (the region not enclosed by the dashed line in Figure 5) within the preform 1 into which the rod member 22 is inserted, where the spacer member 26 is not installed, the inner circumferential surface of the preform 1 and the rod body 24 face each other, so the radial gap S2 between the inner circumferential surface of the preform 1 and the mold becomes wider compared to the first region. In the second region, radiant heat from the preform 1 does not easily reach the rod body 24, so the amount of heat absorbed is reduced, and the temperature on the inner circumferential side of the preform 1 does not decrease as easily compared to the first region (i.e., the temperature of the body 3 of the preform 1 does not decrease as easily).

[0053] As described above, with the rod member 22, the degree of temperature reduction (cooling intensity) at each part of the inner circumference of the preform 1 can be selectively adjusted by adjusting the mounting position of the spacer member 26, making it easy to bring the temperature distribution of the preform 1 closer to a desired state. In the example in Figure 5, the temperature adjustment in the circumferential direction of the preform 1 was explained, but the temperature in the axial direction of the preform 1 can also be adjusted using the same method.

[0054] (Blow molding section 13) The blow molding section 13 manufactures a container by performing biaxial stretch blow molding on the preform 1 whose temperature has been controlled by the temperature control section 12. The blow molding section 13 includes a blow cavity mold, which is a pair of split molds corresponding to the shape of the container, a bottom mold, a stretching rod, and an air introduction / exit member (neither of which are shown). The blow molding section 13 blow molds the preform 1 while stretching it. This allows the preform 1 to be shaped into the shape of the blow cavity mold, thereby manufacturing a container.

[0055] (Removal section 14) The removal section 14 is configured to release the neck portion of the container manufactured in the blow molding section 13 from the neck mold 17 and remove the container to the outside of the blow molding apparatus 10.

[0056] <Explanation of the method for manufacturing the container> Next, the method for manufacturing the container using the blow molding apparatus 10 of this embodiment will be explained. Figure 6 is a flowchart showing the steps of the method for manufacturing the container. In this embodiment, a mold adjustment step (S100) is performed before each step (S101 to S104) of the container manufacturing cycle described later is carried out.

[0057] (Step S100: Mold adjustment process) The mold adjustment process is a process of adjusting the mounting position of the spacer member 26 on the rod member 22 according to the temperature variation of the preform 1. As an example, the following work is performed in the mold adjustment process. In the following explanation, the adjustment is made so that the temperature distribution of the preform 1 in the circumferential direction and the thickness distribution of the container are reduced. The concept for adjusting the mounting position of the spacer member 26 in the axial direction is the same as for the circumferential direction.

[0058] First, the blow molding apparatus 10 is test-run to obtain information on the temperature distribution of the preform 1 or the wall thickness distribution of the container before adjustment. For example, if there is a temperature bias in the circumferential direction of the preform 1, the operator attaches a spacer member 26 to the area of ​​the rod body 24 facing the high-temperature part of the preform 1 (or the part where the heat retention is to be reduced) in the circumferential direction. As a result, in the part of the preform 1 that is hot during the test run (or the part where the heat retention is to be reduced), radiant heat from the preform 1 can more easily reach the spacer member 26 and be absorbed, causing the temperature of the inner circumference of the preform 1 in that part to decrease (i.e., the temperature of the body 3 of the preform 1 in that part to decrease). Therefore, the adjusted preform 1 can be brought closer to the desired temperature distribution.

[0059] Furthermore, when adjusting the mounting position of the spacer member 26 based on the wall thickness distribution of the container manufactured during the test run, the following procedure can be followed. In a one-stage blow molding process, the high-temperature areas of the preform 1 retain a large amount of heat, making the preform 1 more easily stretched. In other words, the areas of the container with thin walls correspond to the high-temperature areas of the preform 1. On the other hand, the low-temperature areas of the preform 1 retain less heat compared to the high-temperature areas, making the preform 1 less easily stretched. In other words, the areas of the container with thick walls correspond to the low-temperature areas of the preform 1.

[0060] Therefore, when adjusting the temperature control mold based on the thickness distribution of the container, the areas with thin walls of the container are considered high-temperature areas of the preform 1, and the areas with thick walls of the container are considered low-temperature areas of the preform 1, and the mounting position of the spacer member 26 can be adjusted in the same manner as described above.

[0061] Furthermore, the adjustment of the mounting position of the spacer member 26 can also be applied when creating differences in wall thickness (thickness of the resin wall) in the circumferential or axial direction of the container body. When creating differences in wall thickness of the container, the spacer member 26 is attached to the part of the body 3 of the preform 1 corresponding to the part of the container body to be thickened, thereby increasing the cooling strength (amount of heat absorbed) by the rod member 22 at that part and reducing the amount of stretching of the preform 1 at that part. Once the above mold adjustment process is completed, each step of the container manufacturing cycle shown below is executed.

[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, which is shaped like a preform and formed by the injection cavity mold, the injection core mold, and the neck mold 17 of the transport mechanism 16, thereby manufacturing a preform 1. Then, after the injection (filling and holding pressure) of the resin material is completed, or after a minimum cooling time provided after the completion of injection, the injection mold of the injection molding section 11 is opened.

[0063] While not particularly limited, from the viewpoint of manufacturing containers in a high-speed molding cycle, it is preferable to open the mold in step S101 without allowing a cooling time for the preform 1 in the injection mold after the injection (filling and holding pressure) of the resin material is completed. On the other hand, if minimal cooling of the preform 1 is performed in the injection mold, it is preferable that the time for cooling the resin material after the injection of the resin material is completed in the injection molding section 11 (cooling time) is 1 / 2 or less of the time for injecting the resin material (injection time).

[0064] In this embodiment, since there is no (or very short) cooling time for the preform 1 in the injection mold after holding pressure, the skin layer (solidified surface layer) and core layer (softened or molten inner layer) of the preform are formed to be thinner and thicker compared to when the preform is sufficiently cooled in the injection mold. In other words, in this embodiment, the thermal gradient between the skin layer and the core layer is large, and a preform 1 with high temperature and high heat retention is molded.

[0065] Once the injection molding of the preform 1 is complete, the mold in the injection molding section 11 opens, and the preform 1 is released from the injection cavity mold and the injection core mold. Next, the transfer plate of the transport mechanism 16 moves to rotate by a predetermined angle, and the preform 1, held in the neck mold 17, is transported to the temperature control section 12 while still retaining the heat from the injection molding process.

[0066] (Step S102: Temperature adjustment process) Next, the temperature adjustment unit 12 adjusts the temperature of the preform 1 to bring it closer to a temperature suitable for the final blowing.

[0067] In the temperature control process, the preform 1 held in the neck mold 17 is housed in the temperature-controlled cavity mold 21 as the transfer plate descends, and the rod member 22 is inserted into the preform 1. If the preform 1 released from the injection mold in the injection molding process is hot and heavy, when it is adjusted to a temperature suitable for blow molding in the temperature-controlled cavity mold 21, the blow-molded parts (body 3 and bottom 4) may draw down or deform. Also, when blow-molding a container with a hollow handle as disclosed in international patent application WO2025-084330, the optimal blow-molding temperature for the preform 1 is considerably higher than the glass transition temperature of the resin material and the normal optimal blow-molding temperature, so draw-down may occur.

[0068] With the rod member 22 inserted into the preform 1, when the intake mechanism is activated (started), air is drawn into the rod body 24 from the intake hole 25b of the tip piece 25 at the bottom 4 of the preform 1. As a result, the bottom 4 of the preform 1 is supported from above by the suction of the rod member 22, and the drawdown of the preform 1 in the temperature control unit 12 is suppressed.

[0069] In the temperature control unit 12, the outer circumferences of the body 3 and bottom 4 of the preform 1 are heated non-contact by radiant heat from the temperature control cavity mold 21. The inner circumference of the body 3 of the preform 1 absorbs heat when the rod member 22 receives radiant heat from the preform 1, and the temperature can be reduced non-contact by the rod member 22. The bottom 4 of the preform 1 is in contact with the tip piece 25 of the rod member 22, but the tip piece 25 is made of a material with higher thermal insulation properties than the rod body 24. Therefore, the inner circumference of the bottom 4 of the preform 1 is less affected by the heat from the rod member 22.

[0070] Furthermore, a spacer member 26 is attached to the rod body 24 of the rod member 22 to match the high-temperature areas (or areas where heat retention is to be reduced) of the preform 1. As a result, the high-temperature areas (or areas where heat retention is to be reduced) of the preform 1 are cooled (heat absorbed) more strongly than other areas by the spacer member 26, allowing the preform 1 to approach the desired temperature distribution. When the preform 1 reaches a temperature suitable for blow molding due to the heat treatment from the temperature-controlled cavity mold 21 and the heat absorption treatment of the rod member 22, the intake mechanism is stopped and the support of the bottom 4 of the preform 1 by the rod member 22 is released.

[0071] After the temperature adjustment process, the transfer plate of the transport mechanism 16 moves to rotate by a predetermined angle, and the temperature-adjusted preform 1 held in the neck mold 17 is transported to the blow molding section 13.

[0072] (Step S103: Blow molding process) Next, blow molding of the container is performed in the blow molding section 13. First, the blow cavity mold, which is in an open state, is closed to house the preform 1 in the mold space, and the air introduction / exit member (e.g., blow core) is lowered so that it comes into contact with the neck portion 2 of the preform 1. Then, the stretching rod (vertical axis stretching member) is lowered to press down on the bottom portion 4 of the preform 1 from the inside, and while stretching along the vertical axis as needed, blow air is supplied from the air introduction / exit member to stretch the preform 1 along the horizontal axis. As a result, the preform 1 expands and is shaped to closely fit into the mold space of the blow cavity mold and blow molded into a container. The bottom mold waits in a lower position that does not come into contact with the bottom portion 4 of the preform 1 before the blow cavity mold is closed, and is controlled to quickly rise to the molding position before or after the mold is closed.

[0073] (Step S104: Container removal process) When blow molding is complete, the blow cavity mold is opened. This allows the container to be moved out of the blow molding section 13. Next, the transfer plate of the transport mechanism 16 moves by a predetermined angle, and the container is transported to the removal section 14. In the removal section 14, the neck of the container is released from the neck mold 17, and the container is removed to the outside of the blow molding apparatus 10.

[0074] This completes one container manufacturing cycle in the container manufacturing method. Subsequently, by moving the transfer plate of the transport mechanism 16 by a predetermined angle, each of the steps S101 to S104 described above is repeated. When the blow molding apparatus 10 is in operation, the manufacturing of four sets of containers, each with a time difference between each step, is performed in parallel. Also, due to the structure of the blow molding apparatus 10, the injection molding step, temperature adjustment step, blow molding step, and container removal step are all the same length. Similarly, the transport time between each step is also the same length.

[0075] The effects of this embodiment are described below. In the temperature control unit 12 of this embodiment, a rod member 22 is inserted into the preform 1. The rod member 22 supports the inner circumferential surface of the bottom 4 of the preform 1 by attracting (being attracted) to the tip piece 25 by drawing air in through the intake hole 25b via the rod body 24. Therefore, according to this embodiment, the bottom 4 of the preform 1 is supported from above by the attraction of the rod member 22, so that the drawdown of the preform 1 in the temperature control unit 12 can be suppressed.

[0076] Furthermore, since the rod member 22 adsorbs and supports the bottom 4 of the preform 1 from above, the outer circumferential surface of the bottom 4 of the preform 1 faces the bottom of the temperature-controlled cavity mold 21 with a gap between them. Therefore, according to this embodiment, while suppressing the drawdown of the preform 1, the outer circumferential surface of the bottom 4 of the preform 1 can also be heated by radiant heat using the temperature-controlled cavity mold 21.

[0077] Furthermore, the rod body 24 of the rod member 22 is inserted into the preform 1 with a gap between it and the inner circumference of the preform 1, allowing the temperature of the inner circumference of the preform 1 to be reduced without contact. Also, by attaching the spacer member 26 to the rod body 24, the high-temperature area of ​​the preform 1 (or the area where the heat retention is to be reduced) can be cooled more strongly in a localized area than other areas. Therefore, according to this embodiment, the inner circumference of the preform 1 can be brought closer to a desired temperature distribution.

[0078] In this embodiment, one intake hole 25b is formed at the axial center of the tip piece 25. Compared to the case where multiple intake holes are formed, this makes it less likely for the sealing performance between the preform 1 and the tip piece 25 to deteriorate when heating in the heating pot, making it easier to suppress the drawdown of the preform 1 during heating, and also suppressing the occurrence of multiple convex transfer marks on the preform 1 and the container. In addition, in this embodiment, a recess 25c is formed on the tip side of the intake hole 25b that faces the inner circumferential surface of the bottom of the preform 1, and this recess is larger in the radial dimension than the intake hole 25b. This suppresses the phenomenon of the bottom of the preform 1 sticking to the tip piece 25 when the suction of the preform 1 is released.

[0079] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention.

[0080] In the above embodiment, the temperature control unit 12 was described in an example where the inner circumference of the preform 1 is cooled non-contact by the rod member 22. However, the inner circumference of the preform 1 may also be heated non-contact by the rod member 22.

[0081] Figure 7 is a longitudinal cross-sectional view showing a modified example of the temperature control unit 12 of this embodiment. In the description of Figure 7, elements common to the above embodiment are denoted by the same reference numerals, and redundant explanations are omitted as appropriate.

[0082] The temperature control unit 12a shown in Figure 7 comprises a temperature control cavity type (heating pot type) 21 capable of housing the preform 1, and a rod member (heating rod type) 22a inserted into the interior of the preform 1.

[0083] The rod member 22a is an example of an element of a temperature-controlling mold and includes a core portion (rod base end) 23, a rod body 24, a tip piece 25, a spacer member 26, and a heating portion 27. The heating portion 27 is, for example, positioned above the core portion 23 on the base end side and is thermally connected to the rod body 24. The heating portion 27 is composed of, for example, a band heater and heats the inner circumference of the preform 1 by radiant heat via the rod body 24.

[0084] As shown in the example in Figure 7, the inner circumference of the preform 1 can be heated non-contactually by radiant heat from the rod member 22a. In the case of the rod member 22a in Figure 7, when the spacer member 26 is attached, the distance between the inner circumference of the preform 1 and the spacer member 26 becomes smaller, so the radiant heat from the rod member 22a heated by the heating unit 27 can more easily reach the inner circumference of the preform 1. As a result, the inner circumference of the preform 1 can be heated more strongly at the position where the spacer member 26 is attached than at other parts. Therefore, in the example in Figure 7, it is preferable to attach the spacer member 26 to a position corresponding to a low-temperature area of ​​the preform 1 (or an area where it is desired to increase the heat retention).

[0085] Furthermore, the arrangement of the mounting portions for the spacer members 26 on the rod body 24 is not limited to the above embodiment, and the number of mounting portions in the circumferential and axial directions can be arbitrarily changed. Alternatively, the rod body 24 in the above embodiment may not be provided with mounting portions for the spacer members 26, and the temperature control function provided by the spacer members 26 may be omitted in the rod member 22.

[0086] Furthermore, in the above embodiment, multiple types of spacer members 26 with different radial thicknesses may be prepared, and the size of the radial gap between the preform 1 and the spacer member 26 may be adjusted by selecting the type of spacer member 26 to be attached to the rod body 24. Also, protrusions and recesses may be formed on the outer circumferential surface of the spacer member 26.

[0087] Furthermore, the shape of the rod body 24 and the shape of the spacer member 26 are not limited to the above embodiment. For example, the rod body 24 may be formed in a cylindrical shape, and the shape of the spacer member 26 may be formed as a strip-shaped piece with both the inner and outer circumferences being arc-shaped.

[0088] Furthermore, in the above embodiment, an example was described in which the rod member 22 is applied to the temperature control unit 12 of a hot parison type (one-stage type) blow molding apparatus. However, the rod member 22 may also be applied to the heating unit of a cold parison type (two-stage type) blow molding apparatus that heats a preform cooled to room temperature for blow molding.

[0089] Furthermore, in the above embodiment, one intake hole 25b is formed in the axial center of the tip piece 25, and an example was described in which a recess 25c with a radial dimension larger than the intake hole 25b is formed on the tip side of the intake hole 25b. However, multiple intake holes 25b may be formed on the tip surface 25a of the tip piece 25. Also, a recess 25c is not necessarily formed on the tip side of the intake hole 25b.

[0090] Furthermore, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

[0091] 1...Preform, 2...Neck section, 3...Body section, 4...Bottom section, 10...Blow molding apparatus, 11...Injection molding section, 12, 12a...Temperature control section, 13...Blow molding section, 14...Removal section, 15...Injection device, 16...Transfer mechanism, 17...Neck type, 21...Temperature control cavity type, 22, 22a...Rod member, 23...Core section, 24...Rod body, 24a...Bolt hole, 24b...Circumferential surface section, 25...Tip piece, 25a...Tip surface, 25b...Air intake hole, 25c...Recess, 26...Spacer member, 27...Heating section, 28...Bolt

Claims

1. A temperature control mold for controlling the temperature of a bottomed cylindrical preform made of resin, comprising a rod member having a cylindrical rod body inserted into the preform and extending in the axial direction of the preform, and a tip member attached to the tip side of the rod body and in contact with the bottom inner surface of the preform, wherein the tip member has an air intake hole communicating with the internal space of the rod body, and the rod member supports the bottom inner surface of the preform by drawing air in through the air intake hole via the rod body, thereby adhering to the tip member.

2. The temperature control mold according to claim 1, wherein the rod member is detachably attached to the rod body so as to partially cover the rod body and further comprises one or more spacer members for adjusting the radial gap between the rod body and the preform, and the spacer members are thermally connected to the rod body when the rod body is installed.

3. The temperature control mold according to claim 1, wherein one intake hole is formed in the axial center of the tip member, and a recess is formed in the intake hole on the tip side facing the inner circumferential surface of the bottom of the preform, with a radial dimension larger than the intake hole.

4. The temperature control mold according to claim 1, wherein the rod member further has a heating part for heating the rod body, and the rod body is inserted into the preform with a gap between it and the inner circumference of the preform, and the inner circumference of the preform is heated without contact.

5. The temperature control mold according to claim 1, further comprising a cavity mold that houses the preform with a gap between the outer circumference of the preform and the cavity mold, and heats the temperature of the preform from the outside in a non-contact manner.

6. A resin container manufacturing apparatus comprising: a temperature adjustment unit having a temperature adjustment mold for adjusting the temperature of a bottomed cylindrical preform made of resin; and a blow molding unit for blow molding the temperature-adjusted preform to manufacture a resin container, wherein the temperature adjustment mold has a rod member having a cylindrical rod body inserted into the preform and extending in the axial direction of the preform, and a tip member attached to the tip side of the rod body and in contact with the inner circumferential surface of the bottom of the preform, the tip member having an air intake hole communicating with the internal space of the rod body, and the rod member supporting the inner circumferential surface of the bottom of the preform by adsorption to the tip member by drawing air from the air intake hole via the rod body.

7. The apparatus for manufacturing a resin container according to claim 6, further comprising an injection molding unit for injection molding the preform, wherein the temperature adjustment unit adjusts the temperature of the preform, which has retained heat during injection molding.

8. A method for manufacturing a resin container, comprising: a temperature adjustment step of adjusting the temperature of a bottomed cylindrical preform made of resin by applying a temperature adjustment mold; and a blow molding step of blow molding the temperature-adjusted preform to manufacture a resin container, wherein the temperature adjustment mold has a rod member having a cylindrical rod body inserted into the preform and extending in the axial direction of the preform, and a tip member attached to the tip side of the rod body and in contact with the bottom inner surface of the preform, the tip member having an air intake hole communicating with the internal space of the rod body, and the rod member supporting the bottom inner surface of the preform by adsorption to the tip member by drawing air from the air intake hole via the rod body.

9. The method for manufacturing a resin container according to claim 8, further comprising an injection molding step of injection molding the preform, wherein the temperature adjustment step adjusts the temperature of the preform having retained heat during injection molding.

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