Manufacturing method of resin container and temperature control device

Abstract

This method for producing a resin container has: a first step for accommodating an injection-molded bottomed resin preform in a temperature-controlled mold and controlling the temperature of the preform by using the mold; a second step for moving the mold a prescribed amount in the axial direction relative to the preform by using a lifting device, then stopping the mold and causing an air injection part arranged on the upper-surface side of the mold to face the portion of the preform that is to be cooled; a third step for injecting air from the air injection part and locally cooling the portion of the axially positioned preform that is to be cooled; and a blow-molding step for blow-molding the preform that has been temperature-controlled through each of the first to third steps to produce a resin container.

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a resin container and a temperature adjustment device. [Background technology]

[0002] A hot parison type blow molding machine has been known as one of the conventional manufacturing devices for resin containers. The hot parison type blow molding machine is configured to blow mold a resin container by utilizing the heat retained during injection molding of a preform, and is advantageous in that it can manufacture a variety of resin containers with excellent aesthetic appearance compared to the cold parison type.

[0003] Furthermore, when manufacturing containers of special shapes, such as stackable containers or containers with handles, there is a demand for forming specific portions of the container with a large wall thickness in order to ensure the rigidity of the container. When manufacturing this type of container, it is necessary to locally cool the portions of the preform that correspond to the thick portions of the container.

[0004] For example, Patent Document 1 discloses a configuration in which, in forming a container with a triangular cross section, a cooling air nozzle is provided at the upper end of a temperature adjustment pot that pre-blows a preform, and air is blown onto the preform after the pre-blow at locations corresponding to the corners of the container to cool it. In Patent Document 1, the blowing of air is controlled by a timer so that it is timed to coincide with the preform passing through the temperature adjustment pot when the preform is removed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3893067 [Patent Document 2] Patent No. 3340183 Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 discloses a technology in which a cooling means for locally cooling a desired position of a preform is provided in a temperature adjustment pot, and the preform is locally cooled while the temperature adjustment pot is moving downward at a predetermined speed. In Patent Document 1, the timing of the blowing of air, which is the cooling means, is controlled by a timer, but if the conditions such as the specifications of the shape and dimensions of the preform and the moving speed of the preform are different, the cooling part will change significantly even if the timer time is set to the same. Therefore, in the technology of Patent Document 1, the adjustment of parameters for appropriately blowing air is very complicated. For example, when locally cooling a desired position in the axial direction of the preform with pinpoint accuracy, it is very difficult to intuitively set the timing for appropriately blowing air using a timer. Moreover, when manufacturing a variety of containers, it becomes necessary to set optimal parameters for each container, which increases the workload of maintenance. Furthermore, the position of the cooling part is fixed for each mold. Therefore, in the above case, multiple mold parts (position adjustment parts) are required to adjust the position of the cooling part of the preform, and the manufacturing cost of the container becomes very high.

[0007] On the other hand, as disclosed in Patent Document 2, there are cases where a cooling device (accessory device) for locally cooling a desired position on the preform is provided separately on the blow molding machine. However, cooling devices are not cheap, which increases the manufacturing cost of the container. Moreover, in order to avoid extending the molding cycle, the cooling device needs to be provided in the temperature adjustment section of the blow molding machine, but in some cases, the temperature adjustment section must also be provided with other mechanisms (such as a gate cut device) in addition to the temperature adjustment pot. In the above case, since the arrangement space for the cooling device is restricted, which places a limit on the parts where the preform can be cooled, it may be difficult to locally cool the desired position on the preform with the temperature adjustment section. [Means for solving the problem]

[0008] A method for producing a resin container according to one embodiment of the present invention includes the steps of: By driving the lifting device to move the die to one side in the axial direction,A first step of placing an injection-molded resin preform having a bottom in a temperature-controlled mold and controlling the temperature of the preform using the mold; After temperature adjustment For preforms , by driving the lifting device The die is rotated in the axial direction. The other side of a second step of moving the mold a predetermined distance and then stopping the mold so that an air ejection section disposed on the upper surface side of the mold faces a portion of the preform to be cooled; and a third step of ejecting air from the air ejection section to locally cool the portion of the preform to be cooled that is positioned in the axial direction. A fourth step of further moving the mold to the other side in the axial direction by driving the lifting device to move the mold away from the preform; 1st to 5th 4 and a blow molding process for producing a resin container by blow molding the preform that has been temperature-controlled through each of the processes mentioned above. Effect of the Invention

[0009] According to one aspect of the present invention, a desired position of the preform can be locally cooled by the cooling section in the temperature adjustment step, and the position of the cooling section can be easily adjusted. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view of the container of the present embodiment. [Diagram 2] 1 is a diagram showing a schematic configuration of a blow molding device according to an embodiment of the present invention; [Diagram 3] FIG. 4 is a vertical cross-sectional view showing a configuration example of a temperature adjustment unit. [Figure 4] FIG. 4 is a diagram showing a state in which the cavity mold is lowered from the position shown in FIG. [Diagram 5] 13A and 13B are diagrams illustrating examples of the arrangement of air ejection parts of the temperature adjustment part. [Figure 6] 1 is a flow chart showing steps of a blow molding method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiments, in order to make the description easier to understand, structures and elements other than the main parts of the present invention will be described in a simplified or omitted manner. In addition, in the drawings, the same elements are given the same reference numerals. Note that the shapes, dimensions, etc. of each element shown in the drawings are shown only for illustrative purposes, and do not represent the actual shapes, dimensions, etc.

[0012] (Explanation of resin containers) First, a configuration example of a resin container (hereinafter, also simply referred to as a container) according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a perspective view of a container 10 according to this embodiment.

[0013] Container 10 shown in Fig. 1 is a large-capacity (e.g., 15 L to 20 L) stackable container used to store, for example, mineral water, edible oil, etc., and is manufactured by blow molding a resin preform 40 described below. The overall shape of container 10 shown in Fig. 1 is a prismatic column with rounded corners, and its cross section is approximately rectangular. Container 10 has a neck 11 with an open top, a shoulder 12 connected below neck 11, a body 13 connected below shoulder 12, and a bottom 14 closing the bottom end of body 13. Bottom 14 is formed with a recess 15 for receiving neck 11 of container 10 placed below when stacked.

[0014] The containers 10 can be stacked independently with part of the bottom 14 in contact with part of the shoulder 12 of another container 10. At this time, the neck 11 of the lower container 10 sealed with a cap (not shown) is accommodated in the recess 15 in the bottom 14 of the upper container 10. This makes it possible to reduce the storage space for the containers 10 and to increase the stability of the containers 10 when stacked.

[0015] In a rectangular and large-capacity container 10 as shown in Fig. 1, the corner portion (heel portion 16) of the bottom portion 14 where the draw ratio from the preform 40 is maximized is likely to have a reduced wall thickness in the container 10. When the heel portion 16 in this type of container 10 has a reduced wall thickness, the container 10 may not withstand the load and may deform, and particularly the posture during stacking may become unstable. In order to suppress such an event, it is required to locally cool the corresponding portion of the heel portion 16 in the preform 40 before blow molding to make it less likely to be drawn than other portions and make the heel portion 16 thicker.

[0016] (Description of Blow Molding Apparatus) Next, the configuration of the blow molding apparatus of the present embodiment will be described. Fig. 2 is a diagram schematically showing the configuration of the blow molding apparatus 20 of the present embodiment. The blow molding apparatus 20 of the present embodiment is an apparatus of a hot parison method (also referred to as a one-stage method) that blow-molds the container 10 by utilizing the retained heat (internal heat quantity) during injection molding without cooling the preform 40 to room temperature.

[0017] 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 transport mechanism 26. The injection molding section 21, the temperature adjustment section 22, the blow molding section 23, and the take-out section 24 are arranged at positions rotated by a predetermined angle (for example, 90 degrees) around the transport mechanism 26.

[0018] (Transport Mechanism 26) The transport mechanism 26 includes a transfer plate (not shown in Fig. 2) that moves so as to rotate around an axis perpendicular to the plane of the paper in Fig. 2. One or more neck molds 27 (not shown in Fig. 1) for holding the neck of the preform 40 or the container 10 are arranged on the transfer plate 28 at predetermined angles. The transport mechanism 26 transports the preform 40 (or the container 10) with its neck held by the neck mold 27 in the order of the injection molding section 21, the temperature adjustment section 22, the blow molding section 23, and the take-out section 24 by moving the transfer plate 28 by 90 degrees at a time. Note that the transport mechanism 26 further includes a mold opening mechanism for the neck mold 27 and the like.

[0019] (Injection Molding Section 21) The injection molding section 21 includes an injection cavity mold and an injection core mold (not shown), and manufactures a preform 40 shown in Fig. 3 described below. An injection device 25 that supplies a resin material, which is a raw material of the preform 40, is connected to the injection molding section 21.

[0020] In the injection molding section 21, the injection cavity mold, the injection core mold, and the neck mold 27 of the transport mechanism 26 are closed to form a mold space having a preform shape. Then, a resin material is poured from the injection device 25 into the mold space having the preform shape, whereby the preform 40 is manufactured in the injection molding section 21.

[0021] Here, the overall shape of the preform 40 is a cylindrical shape with one end open and the other end closed at its bottom. The preform 40 has a neck portion formed at one end with an opening, a body portion connected to the neck portion and formed into a cylindrical shape, and a bottom portion connected to the body portion and closing the other end.

[0022] Furthermore, the material of the container 10 and the preform 40 is a thermoplastic synthetic resin, and can be appropriately selected depending on the application of the container 10. Specific types of materials include, for example, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexane dimethylene terephthalate), Tritan (Tritan (registered trademark): a copolyester manufactured by Eastman Chemical Co.), 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).

[0023] Incidentally, even when the injection molding section 21 is opened, the neck mold 27 of the transport mechanism 26 is not opened, but continues to hold and transport the preforms 40. The number of preforms 40 that are molded simultaneously in the injection molding section 21 (i.e., the number of containers 10 that can be molded simultaneously by the blow molding device 20) can be set appropriately.

[0024] (Temperature adjustment section 22) The temperature adjustment unit 22 cools or heats the preform 40 in a high temperature state after injection molding in the mold to adjust the temperature, and has the function of uniformly heating and removing temperature deviation of the preform 40. Moreover, the temperature adjustment unit 22 in this embodiment has the function of locally cooling a desired portion of the preform 40 by blowing air onto the preform 40 after the temperature has been adjusted in the mold.

[0025] Fig. 3 is a vertical cross-sectional view showing a configuration example of the temperature adjustment section 22. The temperature adjustment section 22 shown in Fig. 3 is configured to pre-blow the preform 40 manufactured in the injection molding section 21, and mold an intermediate molded body 41 having a bottomed cylindrical shape with a body portion larger in diameter than the preform 40. The intermediate molded body 41 is an example of the preform 40 when pre-blow is performed.

[0026] The temperature adjustment section 22 includes a cavity mold (temperature-controlled pot mold) 31 capable of accommodating the preform 40 produced in the injection molding section 21, an upper support plate 32 which is an example of a plate, a lower support plate 33, a movable table 34, a shaft (guide member) 35, a drive cylinder 36, an air ejection section 37, and a lower fixed plate 38.

[0027] The cavity mold 31 is a mold that is open on the upper side and has an internal mold space that corresponds to the shape of the intermediate molded body 41. The cavity mold 31 uniformly heats the intermediate molded body 41 and removes temperature deviations, and adjusts the temperature of the intermediate molded body 41 to a temperature suitable for blow molding (for example, about 90°C to 105°C) and to have a temperature distribution suitable for the container shape to be formed. The temperature adjustment unit 22 also has the function of cooling the intermediate molded body 41 in a high-temperature state.

[0028] The cavity mold 31 is configured to allow different temperature settings in the axial direction of the preform. For example, the cavity mold 31 is divided into at least two or more parts, an upper cavity mold and a lower cavity mold, in the axial direction of the preform. As an example, the cavity mold 31 is configured as a four-part mold, and in FIG. 3, the first mold 31a, which is the upper cavity mold, and the second mold 31b, the third mold 31c, and the fourth mold 31d, which are the lower cavity molds, are stacked in this order from the top side in the figure. An upper support plate 32 is arranged on the upper surface side of the first mold 31a, and a lower support plate 33 is arranged between the lower surface of the outer periphery of the first mold 31a and the upper surface of the outer periphery of the second mold 31b. More specifically, the lower support plate 33 is preferably arranged in a state in which it abuts on a step portion formed on the outer periphery of the second mold 31b and is not in contact with the lower end of the outer periphery of the first mold 31a. Moreover, it is preferable that the upper support plate 32 is arranged in a state of not contacting the upper surface of the first mold 31a. Moreover, the fourth mold 31d is placed on the upper surface of the movable table 34 (or a spacer 34a described later). Note that a spacer 34a is arranged between the cavity mold 31 and the movable table 34 to adjust the axial position of the cavity mold 31.

[0029] The lower support plate 33 and the movable table 34 are connected and integrated by a plurality of support columns (not shown) extending in the axial direction of the preform 40. The second mold 31b to the fourth mold 31d are connected and integrated, or are fixed to the movable table 34 by being sandwiched between the lower support plate 33 and the movable table 34. The lower support plate 33 has two block-shaped members 33a at opposing positions on the upper surface. The upper support plate 32 is fixed to the upper surface of the block-shaped members 33a by connecting members 32c such as bolts.

[0030] The first mold 31a is a mold facing the outer peripheral surface of the preform 40 near the neck portion. The first mold 31a is composed of a pair of split molds, and can be opened and closed in the depth direction in the figure by a driving mechanism (e.g., an air cylinder) not shown. For example, the pair of first molds 31a are supported by a guide mechanism provided on a block-shaped member 33a so as to be movable in the horizontal direction between a mold closing position and a mold opening position. By opening and closing the first mold 31a, it is possible to remove the intermediate molded body 41 after the preliminary blow from the cavity mold 31.

[0031] The second mold 31b and the third mold 31c are molds that face the outer peripheral surface of the body part of the preform 40. The fourth mold 31d is a mold that faces the outer peripheral surface of the bottom part of the preform 40. The bottom surface of the second mold 31b and the top surface of the third mold 31c, and the bottom surface of the third mold 31c and the top surface of the fourth mold 31d are engaged by a spigot structure with, for example, a heat insulating member sandwiched between the molds.

[0032] In addition, a flow path (not shown) through which a temperature control medium (coolant) flows is formed in each of the first mold 31a to the fourth mold 31d of the cavity mold 31. Therefore, the temperature of the first mold 31a to the fourth mold 31d is maintained at a predetermined temperature by the temperature control medium. The temperature of the temperature control medium is not particularly limited, but can be appropriately selected within a range of, for example, 5°C to 80°C, preferably 30°C to 60°C. The temperature distribution in the axial direction of the intermediate molded body 41 can also be changed by changing the temperatures of the first mold 31a to the fourth mold 31d, respectively.

[0033] Furthermore, the temperature adjustment unit 22 has a core member (not shown) that supplies and exhausts compressed air into the preform 1. The core member is inserted from above into the inside of the neck mold 27 and the preform 40, and in the state inserted into the neck mold 27, is abutted airtightly against the neck portion of the preform 40. During the preliminary blow, compressed air is introduced into the preform 40 from the core member, causing the preform 40 to expand so as to come into close contact with the cavity mold 31, and is shaped into the shape of the intermediate molded body 41.

[0034] The movable base 34, the shaft 35, the drive cylinder 36, and the lower fixed plate 38 are each disposed below the machine base 29 of the blow molding apparatus 20. Four shafts 35 are provided. Only a pair of shafts 35, one on the left and one on the right, are shown in Fig. 3. These shafts 35 extend in parallel in the vertical direction, and connect the machine base 29 and the lower fixed plate 38. When the preform 40 is short or when the rotating plate (transfer plate) supporting the neck mold 27 moves up and down, at least the movable table 34 may be disposed, for example, above the machine base 29 of the blow molding device 20 at the standby position (lowest position). If there is sufficient space in the blow molding device 20, the shaft 35, the drive cylinder 36 and the lower fixed plate 38 may also be disposed above the machine base 29.

[0035] A movable table 34 disposed between the machine base 29 and a lower fixed plate 38 is loosely fitted on each shaft 35. This allows the movable table 34 to translate vertically along the shaft 35 below the machine base 29.

[0036] The drive cylinder 36 is an example of a lifting device and is constituted, for example, by an air cylinder, which is attached to the underside of the lower fixed plate 38 facing upward and moves a piston rod 36a connected to the underside of the movable base 34 forward and backward. The drive cylinder 36 moves the movable base 34 up and down via the piston rod 36a. When the piston rod 36a extends relative to the drive cylinder 36, the movable base 34 moves upward, and when the piston rod 36a contracts relative to the drive cylinder 36, the movable base 34 moves downward. The lifting device may be constituted by using an electric motor (for example, a servo motor, etc.).

[0037] FIG. 4 shows a state in which the cavity mold 31 is lowered from the first position (upper end position, temperature adjustment position) in FIG. 3 to the second position (middle position, local cooling position) after the temperature adjustment in the cavity mold 31. The drive cylinder 36 or the lifting device also has the function of adjusting the axial position of the air ejection part 37 relative to the intermediate molded body 41 by positioning and stopping the movable table 34 in the vertical direction. Specifically, the drive cylinder 36 or the lifting device is provided with a rod fixing mechanism (or a position fixing mechanism of the lifting device) that can fix the piston rod 36a at any lifting position and make the position immovable. After the intermediate molded body 41 is locally cooled by the air ejection part 37 described later, the rod fixing mechanism (or the position fixing mechanism of the lifting device) is released, and the cavity mold 31 is lowered to a position (lower end position, standby position) where it does not interfere with the intermediate molded body 41.

[0038] The air ejection unit 37 is attached to the upper side of the upper support plate 32, and has the function of locally cooling the intermediate molded body 41 by ejecting air. As shown in FIG. 5, at least one air ejection unit 37 is provided around the opening 32b (or the opening of the cavity mold 31) of the upper support plate 32, and for example, four air ejection units are attached at intervals of 90 degrees. Each air ejection unit 37 is arranged facing inward so that a surface 37a on which an air ejection port is provided faces the opening 32b. In addition, the air ejection ports of the multiple (for example, four) air ejection units 37 are each arranged at a position corresponding to the heel portion 16 of the container 10 in the circumferential direction of the intermediate molded body 41. The opening 32b is a through hole through which the intermediate molded body 41 can move up and down without interference, and is formed, for example, in a circular shape when viewed from above. The air ejection unit 37 is arranged outside the opening 32b.

[0039] Moreover, one or more arc-shaped grooves 32a are formed in the upper support plate 32 so as to form an annular shape around the opening 32b, for example, four grooves 32a are formed. The grooves 32a formed in the upper support plate 32 extend along a circumference centered on the preform 40 (intermediate molded body 41) or a circumference centered on the opening 32b. The air blowing part 37 is attached to the groove 32a and positioned. The circumferential attachment position of the air blowing part 37 relative to the preform or opening 32b can be adjusted along the groove 32a.

[0040] (Blow molding section 23) Returning to FIG. 2, the blow molding section 23 performs stretch blow molding on the preform 40 (intermediate molded body 41) whose temperature has been adjusted in the temperature adjustment section 22, to manufacture a container. The blow molding section 23 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 member (blow core mold, neither of which are shown). The blow molding section 23 blow molds the intermediate molded body 41 while stretching it. This allows the intermediate molded body 41 to be shaped into the shape of the blow cavity mold to manufacture the container 10.

[0041] (Removal part 24) The removal section 24 is configured to release the neck portion 11 of the container 10 manufactured in the blow molding section 23 from the neck mold 27 and remove the container 10 to the outside of the blow molding apparatus 20.

[0042] (Explanation of the blow molding method) Next, a blow molding method using the blow molding apparatus of this embodiment will be described below. Fig. 6 is a flow chart showing the steps of the blow molding method.

[0043] (Step S101: Injection molding process) In step S101, in the injection molding section 21, resin is injected from the injection device 25 into a preform-shaped mold space formed by the injection cavity mold, the injection core mold, and the neck mold 27 of the transport mechanism 26, and the preform 40 is manufactured.

[0044] In step S101, when the injection molding of the preform 40 is completed, the injection molding section 21 opens the mold, and the preform 40 is demolded from the injection cavity mold and the injection core mold. Next, the transfer plate 28 of the transfer mechanism 26 moves so as to rotate by a predetermined angle, and the preform 40 held by the neck mold 27 is transferred to the temperature adjustment section 22.

[0045] (Step S102: Temperature adjustment process) Subsequently, in the temperature adjustment section 22, temperature adjustment is performed to bring the temperature of the preform 40 close to the temperature suitable for the final blow. In the temperature adjustment section 22 of the present embodiment, pre-blowing of the preform 40 and temperature adjustment of the intermediate molded body 41 after the pre-blowing are performed.

[0046] In the initial state of the temperature adjustment process, the cavity mold 31 is in a position (standby position) retracted downward with respect to the preform 40. First, by driving the drive cylinder 36, the cavity mold 31 rises together with the movable table 34 to a predetermined position (temperature adjustment position). As a result, as shown in FIG. 3, the preform 40 held by the neck mold 27 is accommodated in the cavity mold 31.

[0047] Then, a core member is inserted into the neck portion of the preform 40 accommodated in the cavity mold 31, and the neck portion of the preform 40 and the core member are in close contact with each other to maintain airtightness between the two. Thereafter, by introducing compressed air from the core member into the preform 40, pre-blowing of the preform 40 is performed (S102a: First step).

[0048] In the preform 40 into which compressed air is introduced by pre-blowing, the body portion bulges out so as to be in close contact with the mold space of the cavity mold 31, and is shaped into the shape of the intermediate molded body 41. The intermediate molded body 41 continues to be in contact with the cavity mold 31 maintained at a predetermined temperature until demolding. Therefore, in the temperature adjustment section 22, the temperature of the intermediate molded body 41 is adjusted so as not to fall below the temperature suitable for blow molding from the outside, and the temperature deviation generated during injection molding is further reduced (S102a).

[0049] When the preliminary blow and the temperature adjustment in the cavity mold 31 are completed, the core member rises and retreats, and the first mold 31a slides to be released from the intermediate molded body 41. This allows the cavity mold 31 to move downward without interfering with the shoulder of the intermediate molded body 41. Thereafter, the drive cylinder 36 drives the cavity mold 31 together with the movable table 34 to descend a predetermined height and stop at a predetermined position (local cooling position) (S102b: second step). This brings the air ejection part 37 into a state facing the vicinity of the bottom of the intermediate molded body 41, as shown in FIG. 4. At this time, the rod fixing mechanism (or the position fixing mechanism of the lifting device) operates to fix the movable table 34, the cavity mold 31, or the upper support plate 32 in an immovable position.

[0050] 4, air is sprayed from the air spraying part 37 toward the intermediate molded body 41. As a result, a desired position, such as the vicinity of the bottom of the intermediate molded body 41, is locally cooled by the air spraying (S102c: third step). The part of the intermediate molded body 41 cooled by the air spraying part 37 corresponds to, for example, the heel part 16 of the container 10.

[0051] After the intermediate molded body 41 is locally cooled, the position fixing by the rod fixing mechanism (or the position fixing mechanism of the lifting device) is released, and the cavity mold 31 is further lowered by the drive cylinder 36 to retreat to the initial state position (standby position). Thereafter, the transfer plate 28 of the conveying mechanism 26 moves so as to rotate by a predetermined angle, and the temperature-adjusted intermediate molded body 41 held by the neck mold 27 is conveyed to the blow molding section 23.

[0052] (Step S103: Blow molding process) Next, in the blow molding section 23, the container 10 is blow molded. First, the blow cavity mold is closed to accommodate the intermediate molded body 41 in the mold space, and the air introduction member (blow core) is lowered to contact the neck of the intermediate molded body 41. Then, a stretching rod (vertical axis stretching member) is lowered to hold the bottom of the intermediate molded body 41 from the inside, and while performing vertical axis stretching as necessary, blow air is supplied from the air introduction member to stretch the intermediate molded body 41 in the horizontal axis. As a result, the intermediate molded body 41 is shaped by swelling so as to be in close contact with the mold space of the blow cavity mold, and is blow molded into the container 10. Note that the bottom mold waits at a lower position where it does not come into contact with the bottom of the intermediate molded body 41 before the blow cavity mold is closed, and quickly rises to the molding position before or after the mold is closed.

[0053] (Step S104: container removal process) When the blow molding is completed, the blow cavity mold and the bottom mold are opened, so that the container 10 can be removed from the blow molding section 23. Next, the transfer plate 28 of the conveying mechanism 26 moves so as to rotate a predetermined angle, and the container 10 is conveyed to the removal section 24. In the removal section 24, the neck portion 11 of the container 10 is released from the neck mold 27, and the container 10 is removed to the outside of the blow molding apparatus 20.

[0054] This completes the series of steps in the blow molding cycle. Thereafter, the transfer plate 28 of the conveying mechanism 26 is moved so as to rotate by a predetermined angle, and the above steps S101 to S104 are repeated. When the blow molding apparatus 20 is in operation, four sets of containers 10 are produced in parallel, with a time difference between each step.

[0055] The effects of this embodiment will be described below. In the temperature adjustment section 22 of the blow molding device 20, temperature bias is reduced in the cavity mold 31, the temperature of which is adjusted for the preform (intermediate molded body 41, as an example) (S102a). After that, the drive cylinder 36 is driven to move the cavity mold 31 a predetermined amount in the axial direction relative to the intermediate molded body 41, and then stopped (S102b). As a result, the air ejection section 37 arranged on the upper surface side of the cavity mold 31 faces the part of the intermediate molded body 41 that should be cooled. Then, air is ejected from the air ejection section 37 to locally cool the part of the intermediate molded body 41 that is positioned in the axial direction and should be cooled (S102c).

[0056] According to this embodiment, the piston rod 36a (or the lifting device) of the drive cylinder 36 is positioned by the rod fixing mechanism (or the position fixing mechanism of the lifting device), so that the air ejection part 37 is positioned in the axial direction at the part of the intermediate molded body 41 to be cooled. This allows air to be ejected at the part of the intermediate molded body 41 to be cooled, thereby locally cooling it. Since the drive cylinder 36 or the lifting mechanism moves the movable table 34 or the cavity mold 31 in the axial direction of the preform, the axial positioning of the air ejection part 37 can be intuitively performed, and the positional accuracy of the part of the intermediate molded body 41 (preform 40) to be locally cooled in the axial direction can also be easily improved. Therefore, the operator can easily perform the work of adjusting the drive amount of the drive cylinder 36 so that the air ejection part 37 faces the part of the preform 40 to be locally cooled. Furthermore, by stopping and positioning the drive cylinder 36, the desired part of the preform can be pinpoint-cooled.

[0057] Furthermore, in this embodiment, the device for localized cooling of the preform, which is provided outside the cavity mold 31, is space-saving, so that the bottom of the preform can be locally cooled without any problems even if a gate cut device or the like is placed near the cavity mold 31 in the temperature adjustment section.

[0058] Furthermore, in this embodiment, the position of the air ejection portion 37 can be adjusted circumferentially along the groove 32a formed in the upper support plate 32, making it easy to precisely adjust the area of ​​the preform to be locally cooled in the circumferential direction.

[0059] The present invention is not limited to the above-described embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.

[0060] In the above embodiment, an example has been described in which the vicinity of the bottom of the preform is locally cooled with air, but the portion of the preform that is locally cooled by the temperature adjustment unit 22 is not limited to the above. For example, when manufacturing a container with a handle, air may be blown onto a portion of the preform that corresponds to the base of the handle in the axial direction of the preform to locally cool it.

[0061] In the above embodiment, after the preliminary blow for shaping the preform 40 into the intermediate molded body 41, a cooling blow (cooling blow) for cooling the intermediate molded body 41 may be performed. When the cooling blow is performed by the temperature adjustment unit 22, the intermediate molded body 41 in a high temperature state is rapidly cooled, which makes it easier to suppress whitening (whitening turbidity) due to spherulite generation crystallization that may occur when the intermediate molded body is slowly cooled.

[0062] In the above embodiment, a configuration example in which the temperature adjustment unit 22 performs preliminary blowing has been described, but the temperature adjustment unit 22 may apply a heating pot mold as the cavity mold 31 without performing preliminary blowing. The heating pot mold is temperature-adjusted by a heating member (not shown) such as a band heater (ring-shaped heater) or a rod-shaped heater, and the preform is heated from the outer periphery side by heat from the heating pot mold without contacting the heating pot mold, and the temperature is adjusted (S102a: first step when preliminary blowing is not performed). Furthermore, when preliminary blowing is not performed, a mold member for temperature adjustment inserted inside the preform, such as a temperature adjustment rod (a member that directly contacts the inner peripheral surface of the preform to adjust the temperature: not shown) or a heating rod (a member that does not contact the inner peripheral surface of the preform to adjust the temperature by radiant heating), may be applied instead of a core member that ejects air. Furthermore, the lower support plate 33 may be omitted from the cavity mold 31 that does not perform preliminary blowing. In this case, the upper support plate 32 and the movable table 34 (or spacer 34a) may be connected together with multiple pillars (not shown) to form an integrated structure, and an upper cavity mold (first mold 31a) and a lower cavity mold (first mold 31b, etc.) may be stacked between them to form the cavity mold 31.

[0063] In addition, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0064] Reference Signs List 10: container, 20: blow molding device, 21: injection molding section, 22: temperature adjustment section, 23: blow molding section, 31: cavity mold, 32: upper support plate, 32a: groove, 34: movable table, 36: drive cylinder, 37: air ejection section, 40: preform, 41: intermediate molded body

Claims

1. A first step of axially moving a mold to one side by driving a lifting device to accommodate an injection-molded resin preform having a bottom in a temperature-controlled mold, and adjusting the temperature of the preform by the mold; a second step of moving the die by a predetermined amount to the other axial direction by driving the lifting device with respect to the preform after the temperature adjustment, and then stopping the die, and bringing an air ejection portion disposed on the upper surface side of the die into opposition to a portion of the preform to be cooled; a third step of blowing air from the air blowing portion to locally cool the portion of the preform that is positioned in the axial direction and that is to be cooled; A fourth step of further moving the mold to the other side in the axial direction by driving the lifting device to move the mold away from the preform; and a blow molding process for producing a resin container by blow molding the preform whose temperature has been adjusted through each of the first to fourth processes. A method for manufacturing a resin container.

2. The air ejection portion is disposed in a circumferential direction of the preform. The method for producing the resin container according to claim 1.

3. The air ejection unit is disposed on a plate having an arc-shaped groove along a circumference centered on the preform, and the circumferential position of the air ejection unit relative to the preform can be adjusted along the groove. The method for producing the resin container according to claim 1.

4. The method further includes an injection molding step of injection molding the preform, The first step of adjusting the temperature of the preform using a mold and the third step of locally cooling the preform are performed on the preform containing the heat retained during injection molding between the injection molding step and the blow molding step. The method for producing the resin container according to claim 1.

5. The resin container is a stackable container that can be stacked with other containers with the bottom of the container in contact with the shoulder of the other container. The method for producing a resin container according to any one of claims 1 to 4.

6. A resin container manufacturing apparatus applicable to the resin container manufacturing method according to claim 1, The apparatus includes at least a temperature adjustment unit that adjusts the temperature of the preform, and a blow molding unit that blow molds the temperature-adjusted preform, The temperature adjustment unit is A lifting device that drives a mold that accommodates the preform in an axial direction; an air ejection unit attached to a plate arranged on the upper surface side of the mold; The plate has an arc-shaped groove along a circumference centered on the preform, The air ejection portion is capable of adjusting a circumferential position with respect to the preform along the groove. Plastic container manufacturing equipment.

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