Manufacturing apparatus for resin containers

Abstract

A production device (1) produces a resin container having a two-layer structure configured from an inner layer constituted of a first resin material, and an outer layer constituted of a second resin material. The production device (1) comprises an injection molding unit (100) and a blow molding unit (500). The injection molding unit (100) molds, by injection, N preforms (N is a natural number of 2 or more) at a time, the preforms each having a two-layer structure comprising an internal layer constituted of the first resin material, and an external layer constituted of the second resin material. The blow molding unit (500) molds, by blowing, M resin containers at a time, from the N preforms, in n batches (n is a natural number of 2 or more), where M is N / n and is a natural number.

Description

Resin container manufacturing device and resin container manufacturing method

[0001] The present disclosure relates to a resin container manufacturing apparatus and a resin container manufacturing method.

[0002] Patent Document 1 discloses a method for manufacturing a resin container from a preform having a two-layer structure consisting of an inner layer made of unused resin material and an outer layer made of recycled material prepared by reusing used resin material.

[0003] International Publication No. 2020 / 251035

[0004] In recent years, there has been growing momentum toward promoting the use of recycled plastic materials. Plastic containers and packaging account for a large proportion of plastic production and have a short life cycle before becoming waste. Therefore, increasing the utilization rate of recycled materials in their production is anticipated. Meanwhile, demand for containers and packaging remains strong, and the production of two-layer containers, which use recycled materials laminated onto virgin resin materials, is expected to increase the production volume per hour. Furthermore, two-layer containers composed of different resin materials are primarily manufactured using the extrusion blow molding method. However, this method generally tends to produce a large amount of waste material (waste material) and requires post-processing such as burr removal and trimming. These issues could be resolved if two-layer containers could be manufactured productively using the injection stretch blow molding method (hot parison blow molding).

[0005] An object of the present disclosure is to provide a new resin container manufacturing device and method that can manufacture two-layered containers at a high production rate per hour.

[0006] A resin container manufacturing apparatus according to one aspect of the present disclosure is an apparatus for manufacturing a resin container having a two-layer structure made up of an inner layer made of a first resin material and an outer layer made of a second resin material, and includes: an injection molding unit that injection-moldes N (N is a natural number of 2 or more) preforms each time, each preform having a two-layer structure made up of an inner layer made of the first resin material and an outer layer made of the second resin material; and a blow molding unit that divides the N preforms into n (n is a natural number of 2 or more) blow moldings and blow-moldes M (M=N / n: M is a natural number) resin containers each time from the preforms.

[0007] A method for manufacturing a resin container according to one aspect of the present disclosure is a method using the above-described manufacturing apparatus.

[0008] According to the present disclosure, it is possible to provide a resin container manufacturing device and a resin container manufacturing method that can manufacture two-layer containers at a high production volume per hour.

[0009] Fig. 1 is a schematic plan view showing a resin container manufacturing apparatus. Fig. 2 is a schematic side view showing a resin container manufacturing apparatus. Fig. 3 is a schematic view showing an embodiment in which an inner layer is injection molded in an injection molding unit. Fig. 4 is a schematic view showing an embodiment in which an outer layer is injection molded outside the inner layer in an injection molding unit. Fig. 5 is a plan view of a conveying unit according to an embodiment.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that, for the sake of convenience of explanation, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0011] Furthermore, in the description of this embodiment, for convenience of explanation, the terms "left-right direction," "front-rear direction," and "up-down direction" will be referred to as appropriate. These directions are relative directions set for the manufacturing apparatus shown in FIGS. 1 and 2. Here, the "up-down direction" is a direction that includes the "upward direction" and the "downward direction." The "front-rear direction" is a direction that includes the "forward direction" and the "rearward direction." The "left-right direction" is a direction that includes the "leftward direction" and the "rightward direction."

[0012] Fig. 1 is a schematic plan view showing the overall appearance of a resin container manufacturing apparatus 1 according to an embodiment. Fig. 2 is a schematic side view showing the overall appearance of the manufacturing apparatus 1 according to an embodiment. The manufacturing apparatus 1 has an injection molding section 100 that molds a resin preform 10, and a blow molding section 500 that blow molds the preform 10 to form a container 20. The manufacturing apparatus 1 further has a conveying section 300 that conveys the preform 10 molded in the injection molding section 100 to the blow molding section 500 (Fig. 1). In the manufacturing apparatus 1, the injection molding section 100, the conveying section 300, and the blow molding section 500 are arranged in this order along a rear direction (an example of a first direction).

[0013] The manufacturing apparatus 1 is a hot parison (1.5-stage) manufacturing apparatus that performs blow molding on N (where N is a natural number greater than or equal to 2) preforms 10 that are simultaneously injection-molded in n (where n is a natural number greater than or equal to 2) batches to produce M (where M = N / n: M is a natural number) preforms at a time. The container 20 manufactured by the manufacturing apparatus 1 has a two-layer structure consisting of an inner layer made of a first resin material and an outer layer made of a second resin material. For example, the first resin material (synthetic resin) may be a virgin resin material, and the second resin material may be a recycled material prepared by reusing used resin material. The first resin material and the second resin material may be the same type of resin material or different types of resin materials. When the first resin material and the second resin material are the same type of resin material, examples of the first resin material and the second resin material include polyethylene terephthalate, polyethylene, and polypropylene. When the first resin material and the second resin material are the same type of resin material, both the first resin material and the second resin material may be recycled materials as long as there are no hygiene issues for the human body (for example, the contents are liquid detergent, etc.) When the first resin material and the second resin material are different types of resin materials, it is desirable to select the first resin material and the second resin material so that the melting point of the first resin material is higher than the melting point of the second resin material.

[0014] The manufacturing apparatus 1 includes a take-out device 150 that takes out the preforms 10 from the injection molding section 100, a preform transfer device 220 that transfers the preforms 10 from the take-out device 150, and a first reversing section (post-cooling section) 200 that sends the preforms 10 from the preform transfer device 220 to a conveying section 300 (FIG. 2). The manufacturing apparatus 1 also includes a second reversing section 400 that sends the preforms 10 from the conveying section 300 to a blow molding section 500 (FIG. 2).

[0015] The injection molding unit 100 injection-moldes N preforms 10 (N is a natural number equal to or greater than 2) at a time. Specifically, the injection molding unit 100 is configured to simultaneously injection-mold N preforms 10 in n (n is an integer equal to or greater than 2) parallel rows parallel to the left-right direction, with M preforms (M=N / n: M is a natural number) in each row. The preforms 10 manufactured by the injection molding unit 100 have a two-layer structure consisting of an inner layer made of virgin resin material and an outer layer made of recycled material. FIG. 3 is a schematic diagram showing how the inner layer 10a is injection-molded in the injection molding unit 100. FIG. 4 is a schematic diagram showing how the outer layer 10b is injection-molded outside the inner layer 10a in the injection molding unit 100. The injection molding unit 100 will be described in detail below with reference to FIGS. 1 to 4.

[0016] The injection molding unit 100 includes a first injection molding unit and a second injection molding unit. The first injection molding unit includes a first injection unit 110a for injecting a first layer of resin material and a first cavity mold 112a connected to the first injection unit 110a (FIG. 1). The second injection molding unit includes a second injection unit 110b for injecting a second layer of resin material and a second cavity mold 112b connected to the second injection unit 110b (FIG. 1). In this embodiment, the first injection unit 110a is configured to inject a first resin material (e.g., virgin resin material 12a), and the second injection unit 110b is configured to inject a second resin material (e.g., recycled material) 12b (FIGS. 3 and 4). In this embodiment, the first layer corresponds to the inner layer 10 a of the preform 10 , and the second layer corresponds to the outer layer 10 b of the preform 10 .

[0017] In this embodiment, the first cavity mold 112a and the second cavity mold 112b are arranged in this order along a rear direction (an example of a first direction) (FIG. 1). In this embodiment, the first cavity mold 112a is arranged rearward relative to the first injection unit 110a, and the second cavity mold 112b is arranged rightward relative to the second injection unit 110b (an example of a second direction intersecting the first direction) (FIG. 1). The first cavity mold 112a and the second cavity mold 112b are each fixed to a base plate 100b on a machine stand, and are cooled by flowing cooling water at a predetermined temperature (e.g., 10°C to 20°C).

[0018] The injection molding unit 100 includes a rotating member (rotating platen) 120 intermittently rotatably mounted on a movable platen 120a, an upper base 100a located above the rotating member, a pair of neck dies 114 and a pair of core dies 116 attached to the rotating member 120, four tie bars 140 fixed to the upper base 100a, an elevation drive unit 120b that drives the rotating member 120 up and down via the movable platen 120a along the tie bars 140, a mold clamping mechanism 100d that drives the movable platen 120a or the rotating member 120 to clamp, and a lower base 100c fixed to the lower ends of the tie bars 140. The pair of neck dies 114 and the pair of core dies 116 are configured to be movable to positions where the first cavity die 112a and the second cavity die 112b are respectively provided by the rotation of the rotating member 120. The pair of core dies 116 are cooled by flowing cooling water at a predetermined temperature (e.g., 10°C to 20°C). The rotating member 120 has a rotation drive unit 120c and is configured to be able to rotate 180° intermittently. The rotating member 120 also has a pair of demolding drive units 120e that demold the preform 10 from the pair of neck dies 114 and the pair of core dies 116. The operation during molding of the preform 10 is, for example, as follows. First, the lift drive unit 120b lowers the movable platen 120a (or the rotating member 120) along the tie bars 140 from an upper standby position, thereby closing the pair of neck dies 114, the pair of core dies 116, and the pair of cavity dies (first cavity dies 112a and second cavity dies 112b). At this time, the movable platen 120a (or the rotating member 120) stops at a mold clamping position lower than the standby position, and the pressure-receiving member 120d provided on the upper surface of the movable platen 120a is positioned below the lower surface of the upper base 100a through a through-hole (not shown) in the upper base 100a. Next, a shutter member (not shown) provided on the lower surface of the upper base 100a is closed, and the mold clamping mechanism 100d is driven to abut the upper end of the pressure-receiving member 120d against the shutter member (not shown) to perform mold clamping. Thereafter, the first injection unit 110a injects the molten first resin material into the first cavity mold 112a.After the first injection molding is completed, the mold clamping mechanism 100d is depressurized, the shutter member (not shown) is opened, the movable platen 120a (or the rotating member 120) is raised and returned to the standby position, and the rotating member 120 is rotated 180° by the rotation drive unit 120c. At this time, the neck mold 114 and core mold 116 holding the first layer are moved from the first injection molding unit to the position of the second injection molding unit. At the same time, another set of neck mold 114 and core mold 116 is moved from the second injection molding unit to the first injection molding unit. Thereafter, the movable platen 120a (or the rotating member 120) is lowered to clamp the mold, as described above, and the second injection unit 110b injects the molten second resin material into the second cavity mold 112b (at the same time, the first injection molding is also performed). After the second injection molding is completed, the movable platen 120a (or the rotating member 120) is raised to open the mold in the same manner as described above, and the mold release drive unit 120e of the movable platen 120a is driven to drop the preform 10 onto the holding member 152, which will be described later. After the mold release, the rotating member 120 is rotated to move the empty neck mold 114 and core mold 116 from the position of the second injection molding unit to the position of the first injection molding unit.

[0019] 1, the number N of preforms simultaneously injection molded in the injection molding section 100 may be, for example, a maximum of 24 (3 rows x 8). If the preform diameter is large, four preforms may be arranged in each row, for a total of N = 12 in three rows. Furthermore, the number N of preforms simultaneously injection molded in the injection molding section 100 may be, for example, a maximum of 36 (3 rows x 12).

[0020] Returning now to the description of other components of the manufacturing apparatus 1, the removal device 150 is configured to remove N preforms 10 molded using the second cavity mold 112b of the injection molding section 100. The removal device 150 is configured to be able to horizontally move N (e.g., 3 rows x 8) holding members 152 (e.g., pots) between a receiving position P1 below the core mold 116 and a delivery position P2 outside the space surrounded by the tie bars 140. The receiving position P1 may be the position where the second cavity mold 112b is provided.

[0021] The preform transfer device 220 transfers N preforms 10 held by the three rows of holding members 152 of the take-out device 150 located at the delivery position P2 shown in Fig. 2 to the first reversal section 200. The preform transfer device 220 has a preform holder 222, a first transfer mechanism 224 that raises and lowers the preform holder 222 in the vertical direction, and a second transfer mechanism 226 that horizontally moves the preform holder 222 and the first transfer mechanism 224 in the front-to-rear direction. The drive sources for the first transfer mechanism 224 and the second transfer mechanism 226 are, for example, air cylinders or servo motors.

[0022] The first inversion unit 200 is a section for post-cooling (additional cooling) the preforms 10. It is configured to invert the upright preforms 10 molded in the injection molding unit 100 into an inverted position with the necks facing downward, and deliver them to the conveying unit 300. The first inversion unit 200 includes a first inversion member 210. The first inversion member 210 has N first inversion pots 212 and N second inversion pots 214 arranged opposite the first inversion pots 212. The first inversion pots 212 and the second inversion pots 214 (first inversion member 210) are configured to be intermittently inverted 180° around their axes. The first inversion member 210 is configured to be raised and lowered by a ball screw or the like driven by a drive source 216 (e.g., a servo motor). The first inversion pots 212 and the second inversion pots 214 are configured to cool the preforms 10 contained therein.

[0023] The conveying section 300 conveys N preforms 10 injection-molded in the injection molding section 100 to the blow molding section 500 in n batches, M at a time. Specifically, the conveying section 300 is configured to convey the preforms 10 conveyed from the injection molding section 100 to the conveying section 300 via the first reversing section 200 to the blow molding section 500. FIG. 5 is a plan view showing one embodiment of the conveying section 300. The conveying section 300 includes a plurality of first conveying members 310 configured to be able to support the preforms 10. The M first conveying members 310 are connected by connecting members to form a set of first conveying members 310. The connecting members of the set of first conveying members 310 are configured to be driven by a first conveying drive section 320 and a second conveying drive section 330, which will be described later. In Figure 5, the position of the leading first conveying member 310 (or preform 10) in a set of first conveying members 310 is marked with a double circle to distinguish it from the other seven. Each first conveying member 310 is configured to be rotatable about its axis. Note that the first conveying members 310 do not have to be connected. In this case, each first conveying member 310 is provided with a member that meshes with a continuously and intermittently driven member such as a sprocket. The conveying section 300 is configured to be able to convey or hold preforms 10 for multiple injection molding batches (for example, 24 (36) x 5 preforms 10 for five injection molding runs).

[0024] The transport unit 300 has a looped transport path formed by guide rails and the like, and is configured to circulate and transport the first transport member 310 along the transport path. The transport unit 300 includes a first transport drive unit 320 (sprockets 320a, 320b, 320c, and 320d) that continuously drives the first transport member 310, and a second transport drive unit 330 (sprockets 330a, 330b, and 330c) that intermittently drives the first transport member 310. In the first transport drive unit 320, sprocket 320d, sprocket 320c, sprocket 320b, and sprocket 320a are arranged in this order from the upstream side. In the second transport drive unit 330, sprocket 330a, sprocket 330b, and sprocket 330c are arranged in this order from the upstream side.

[0025] The region where the first conveying member 310 is continuously driven by the first conveying drive unit 320 is the continuous conveying region T1. The region where the first conveying member 310 is intermittently driven by the second conveying drive unit 330 is the intermittent conveying region T2. ​​The continuous conveying region T1 is located upstream of the intermittent conveying region T2 in the conveying unit 300. The continuous conveying region T1 is provided with a heating unit 360 that heats the preforms 10 to a temperature suitable for blow molding. The heating unit 360 is disposed on a path extending from sprockets 320c, 320b, and 320a in the continuous conveying region T1. The heating unit 360 can be configured by arranging heaters (e.g., quartz heaters) and reflectors spaced apart in the conveying direction in multiple stages in the height direction (vertical direction) on both sides of the conveying unit 300 in the continuous conveying region T1. Air may be blown out from the back of the heater within the heating unit 360. The conveying section 300 can convey or hold multiple injection batches of preforms 10. Therefore, while a preform 10 is being molded in the injection molding section 10, the preforms 10 molded previously can be heated or temperature-controlled for a time longer than the injection molding time (for example, if the heating section 360 can accommodate first conveying members 310 for two injection batches, for a time twice the injection molding time).

[0026] The transport section 300 also includes a parallel drive device 370 (FIG. 2) located below the first reversing section 200, which drives a set of (n+1) or more (e.g., four (four rows)) first transport members 310 in parallel. The parallel drive device 370 is configured by attaching both ends of multiple transport rails to two chains 374 stretched over two sprockets 372a, 372b at each end in the front and rear directions. When one of the sprockets 372a, 372b rotates by one step, the transport rail is moved by one step. The leading row of the set of first transport members 310 arranged on the parallel drive device 370 is configured to be pushed leftward by a carry-out device (not shown) comprised of, for example, an air cylinder. As a result, the set of first transport members 310 carrying preforms 10 sequentially engage with the continuously driven sprocket 320d and are continuously transported. The parallel drive device 370 transports one set of first transport members 310 leftward and then moves another set of first transport members 310 forward by one step. The rearmost row of the parallel drive device 370 is configured to receive the set of first transport members 310 that is not carrying preforms 10 and is sent from the sprocket 330c.

[0027] The leading first conveying member 310 of the set of first conveying members 310 in the leading row is carried out by the carry-out device and engages with the most upstream sprocket 320d, and a continuous conveying force is applied from sprocket 320d to the set of first conveying members 310. The driving force applied to each set of first conveying members 310 that engages with the four continuously driven sprockets 320a, 320b, 320c, and 320d present in the continuous conveying region T1 pushes another set of first conveying members 310 that is not engaged with a continuously driven sprocket further upstream. As a result, multiple sets of first conveying members 310 are continuously conveyed along the conveying direction in the continuous conveying region T1.

[0028] The second reversing unit 400 is disposed between sprockets 330a and 330b in the intermittent conveying region T2 of the conveying unit 300 (FIGS. 1 and 2). The second reversing unit 400 includes a second reversing member (not shown) that reverses the preforms 10 conveyed by the conveying unit 300 to the position of the second reversing unit 400 from an inverted state to an upright state and delivers them to the blow molding unit 500. The set of first conveying members 310 is intermittently driven by the second conveying drive unit 330 so that the set of first conveying members 310 stops at the position of the second reversing unit 400 for a predetermined period of time.

[0029] The blow molding unit 500 is configured to divide N preforms 10 into n runs (n ​​is a natural number greater than or equal to 2) and blow-mold M (M = N / n: M is a natural number) containers 20 from the preforms 10 per run. The blow molding unit 500 includes a split blow cavity mold that can be opened and closed in the left-right direction and defines the shape of the body of the container 20, a bottom mold that can be raised and lowered and defines the bottom of the container 20, and a second conveying member 530 for conveying the preforms 10 and the containers 20 in the front-to-rear direction. The blow molding unit 500 may also include a stretch rod, a blow core mold, a neck mold, etc. When a stretch rod is included, the container 20 is formed by biaxial stretching using blown air and vertical axis drive of the stretch rod. The number of blow cavity molds required to produce N preforms 10 is M, which is smaller than N. This reduces mold costs and further reduces the space required for the manufacturing apparatus 1.

[0030] The second conveying member 530 is a chuck member that grips and intermittently conveys M preforms 10 or containers 20 by their neck portions. The second conveying member 530 has a holding arm that grips the neck portions of the preforms 10 or containers 20. The second conveying member 530 has an inlet section 534 and an outlet section 536 integrally formed therewith and configured to reciprocate back and forth. This reciprocating drive is realized, for example, by a servo motor. The inlet section 534 reciprocates between the preform receiving position B1 and the blow molding position B2, and the outlet section 536 reciprocates between the blow molding position B2 and the removal position B3. The holding arms are driven to open and close together in the left-right direction by, for example, the driving force of an air cylinder. Furthermore, the pitch of each holding arm of the inlet section 534 (the distance between each preform) is configured to be convertible from a narrow pitch at the preform receiving position B1 to a wide pitch at the blow molding position B2 when moving from the preform receiving position B1 to the blow molding position B2.

[0031] The following describes a method for manufacturing a resin container using the manufacturing apparatus 1 according to this embodiment. The manufacturing method includes a step of injection-molding a preform 10 in the injection molding section 100, and a step of blow-molding the transported preform 10 into a container 20 in the blow molding section 500. The manufacturing method also includes a step of transporting the preform 10 molded in the injection molding section 100 to the blow molding section 500, and a step of heating the preform 10 while transporting it to the blow molding section 500.

[0032] The process for injection molding the preform 10 will be described below. First, in the injection molding section 100, the neck mold 114 and core mold 116 are clamped to the first cavity mold 112a, and a first resin material (e.g., virgin resin material) 12a is injected from the first injection unit 110a into the formed cavity to injection-mold the inner layer 10a (FIG. 3). The neck mold 114 and core mold 116 holding the inner layer 10a are then rotated by the rotating member 120 and moved to a position where the second cavity mold 112b is located. The neck mold 114 and core mold 116 holding the inner layer 10a are then clamped to the second cavity mold 112b, and a second resin material (e.g., recycled material) 12b is injected from the second injection unit 110b into the formed cavity to injection-mold the outer layer 10b around the inner layer 10a (FIG. 4). As a result, N preforms 10 each having a two-layer structure composed of an inner layer 10a and an outer layer 10b are molded.

[0033] The process of transporting the preforms 10 molded in the injection molding section 100 to the blow molding section 500 includes a transfer process, a first transfer process, a transport process, and a second transfer process. The transfer process is a process in which the preforms 10 are removed from the injection molding section 100 by the removal device 150, and then the preforms are transported from the removal device 150 to the first reversal section 200 by the preform transport device 220 (FIG. 2). The first transfer process is a process in which the first reversal section 200 inverts the preforms 10 from an upright position to an inverted position and delivers them to the transport section 300 (FIG. 2).

[0034] The conveying step is a step of conveying the preforms 10 in the conveying section 300 to the second reversing section 400 (FIG. 1). In the conveying step, the set of first conveying members 310 in the leading row of the parallel drive device 370 is conveyed leftward by the carry-out device, and the preforms 10 are conveyed to the second reversing section 400 via the continuous conveying region T1 and the intermittent conveying region T2 (FIGS. 1 and 2).

[0035] The second transfer step is a step in which the second reversing section 400 inverts the preforms 10 from an inverted state to an upright state and transfers them to the second conveying member 530 of the blow molding section 500 (FIG. 2). The first conveying member 310, which does not carry any preforms 10, is sent to the parallel drive device 370 by the sprocket 330c (FIGS. 1 and 2).

[0036] The process of heating the preform 10 involves heating the preform 10 during transport by the heating unit 360 provided in the continuous transport region T1 of the transport unit 300. The two-layer preform 10 comes into contact with the low-temperature injection molding molds (the first cavity mold 112a, the second cavity mold 112b, and the core molds 116 corresponding to each cavity mold) twice during molding, and is also held in the first reversal unit 200, so it is prone to becoming low-temperature (the heat retained in the preform 10 is easily released). In the manufacturing apparatus 1 of this embodiment, the heating unit 360 heats the preform 10 to replenish the heat. This allows the temperature of the preform 10 to be adjusted to a temperature suitable for blow molding, even if the two-layer preform 10 molded in the injection molding unit 100 is in a low-temperature state.

[0037] The process of blow-molding the preform 10 into the container 20 involves transporting the preform 10 from the preform receiving position B1 to the blow molding position B2 by the second transport member 530, clamping the blow cavity mold and the bottom mold, and blowing air into the preform 10 to mold the container 20 having a two-layer structure. Through these processes, the container 20 is manufactured.

[0038] According to the manufacturing apparatus 1 configured as described above, containers 20 having a two-layer structure can be blow-molded in the blow molding section 500 in n batches of M pieces each from N preforms 10 having a two-layer structure molded in the injection molding section 100. During the injection molding process of the preforms 10, which is the rate-determining step, the heating process and blow molding process of the preforms 10 molded earlier can be performed in parallel and continuously. This allows two-layer containers 20 to be manufactured at a high production rate per hour.

[0039] According to the manufacturing apparatus 1 having the above configuration, N preforms 10 having a two-layer structure molded using the second cavity mold 112b can be transported in n trips, M pieces at a time, by the transport unit 300 to the blow molding unit 500. As a result, M pieces of containers 20 having a two-layer structure can be blow-molded in n trips in the blow molding unit 500, and two-layer containers 20 can be manufactured at a high production rate per hour.

[0040] According to the manufacturing apparatus 1 having the above configuration, the inner layer 10a can be injection-molded by injecting a first resin material (e.g., virgin resin material) 12a from a first injection unit 110a into a cavity formed by clamping a pair of neck dies 114 and a pair of core dies 116 to a first cavity die 112a (FIG. 3). Next, the pair of neck dies 114 and a pair of core dies 116 holding the inner layer 10a into a cavity formed by clamping a second cavity die 112b, and the second injection unit 110b injects a second resin material (e.g., recycled material) 12b into a cavity formed by clamping a pair of neck dies 114 and a pair of core dies 116 holding the inner layer 10a, thereby injection-molding a two-layer preform 10 having an outer layer 10b on the outside of the inner layer 10a (FIG. 4). The pair of neck dies 114 and the pair of core dies 116 are configured to be movable to the positions where the first cavity die 112a and the second cavity die 112b are provided, respectively, by rotation of the rotating member 120, thereby enabling repeated injection molding of two-layer preforms 10. This allows two-layer preforms 10 to be injection molded at a high production rate per hour, and further allows for the manufacture of containers 20 at a high production rate per hour. It is desirable to set the weight ratio of the outer layer 10b (recycled material) to the preform 10 to 20% or more, preferably 30% or more, and more preferably 35% or more. Furthermore, if both the inner layer 10a and the outer layer 10b are made of recycled material, the weight ratio of the recycled material to the two-layer preform 10 is 100%. Even if both the inner layer 10a and the outer layer 10b of the preform 10 are molded from recycled PET material, the use of the two-layer molding method described above allows the body of the preform manufactured in a single injection molding run to be thin-walled and sufficiently cooled. Therefore, even if the recycled material is prone to whitening due to crystallization, whitening in the body of the preform 10 can be suppressed.

[0041] According to the manufacturing apparatus 1 configured as described above, the injection molding section 100, the conveying section 300, and the blow molding section 500 are arranged in this order along the first direction (rearward direction), and in the injection molding section 100, the first cavity mold 112a and the second cavity mold 112b are arranged in this order along the first direction (rearward direction). This allows the two-layer preform 10 to be easily moved to the conveying section 300 after being formed in the second cavity mold 112b. In particular, the preform 10 formed in the second cavity mold 112b can be moved to the conveying section 300 without being obstructed by components or the like present at the position where the first cavity mold 112a is provided. This allows the preforms to be moved efficiently, enabling the containers 20 to be manufactured at a high production rate per hour.

[0042] According to the manufacturing apparatus 1 having the above configuration, the first cavity mold 112a is arranged in a first direction (rearward) relative to the first injection device 110a, and the second cavity mold 112b is arranged in a second direction (rightward) relative to the second injection device 110b that intersects with the first direction (rearward), so that the two-layer preform 10 can be injection molded suitably without interference between the first injection device 110a and the second injection device 110b.

[0043] The present disclosure is not limited to the above-described embodiments and may be freely modified, improved, etc. The material, shape, dimensions, numerical values, form, number, location, etc. of each component in the above-described embodiments are arbitrary and not limited as long as the present disclosure can be achieved.

[0044] In the above embodiment, an embodiment of injection molding of a preform in which the first layer is the inner layer and the second layer is the outer layer has been described, but it is also possible to first injection mold the outer layer as the first layer, and then injection mold the inner layer as the second layer inside the outer layer.

[0045] In the above embodiment, the first cavity mold 112a and the second cavity mold 112b are arranged in this order along the first direction (rear direction) in the injection molding unit 100. However, the first cavity mold 112a and the second cavity mold 112b may be arranged at the same position in the first direction and side-by-side. In this case, the first cavity mold may be arranged in the first direction relative to the first injection device, and the second cavity mold may be arranged in the first direction relative to the second injection device.

[0046] In the above embodiment, a rotating member 120 is described in which a pair of neck dies 114 and a pair of core dies 116 are attached and which can rotate 180° intermittently. However, modifications are possible, such as a rotating member that can rotate 120° intermittently and in which three sets of neck dies and core dies are attached.

[0047] This application appropriately incorporates the contents disclosed in the Japanese patent application (Patent Application No. 2021-120798) filed on July 21, 2021.

[0048] 1: manufacturing apparatus, 10: preform, 10a: inner layer, 10b: outer layer, 20: container, 100: injection molding section, 110a: first injection device, 110b: second injection device, 112a: first cavity mold, 112b: second cavity mold, 114: neck mold, 116: core mold, 120: rotating member, 300: conveying section, 360: heating section, 500: blow molding section

Claims

1. A manufacturing apparatus for a resin container having a two-layer structure composed of an inner layer made of a first resin material and an outer layer made of a second resin material, an injection molding section that injection-molds, one by one, N (N is a natural number of 2 or more) preforms having a two-layer structure composed of an inner layer made of the first resin material and an outer layer made of the second resin material, and a blow molding section that blow-molds, from the preforms, M (M = N / n: M is a natural number) resin containers one by one, dividing the N preforms into n (n is a natural number of 2 or more) times.

2. The injection molding section includes a first cavity mold connected to a first injection device that injects a resin material for the first layer, and a second cavity mold connected to a second injection device that injects a resin material for the second layer. The manufacturing apparatus further has a transport section that transports the preform molded using the second cavity mold to the blow molding section, wherein the transport section transports the N preforms injection-molded in the injection molding section to the blow molding section, M at a time, dividing them into n times. The manufacturing apparatus according to claim 1.

3. The injection molding section includes a first cavity mold connected to a first injection device that injects the first resin material, a second cavity mold connected to a second injection device that injects the second resin material, a rotating member configured to be intermittently rotatable, and a pair of neck molds and a pair of core molds attached to the rotating member. The pair of neck molds and the pair of core molds are configured to be movable to positions where the first cavity mold and the second cavity mold are respectively provided by the rotation of the rotating member. The manufacturing apparatus according to claim 1 or claim 2.

4. The manufacturing apparatus further has a transport section that transports the preform molded in the injection molding section to the blow molding section, wherein the injection molding section, the transport section, and the blow molding section are arranged in this order along a first direction, and in the injection molding section, the first cavity mold and the second cavity mold are arranged in this order along the first direction. The manufacturing apparatus according to claim 3.

5. ​ ​ The manufacturing apparatus according to claim 4, wherein the first cavity mold is arranged in the first direction with respect to the first injection device, and the second cavity mold is arranged in a second direction intersecting the first direction with respect to the second injection device.

6. The first resin material is an unused resin material, and the second resin material is a recycled material prepared by recycling a used resin material. The manufacturing apparatus according to claim 1.