Method and device for manufacturing peeling container

Abstract

The invention relates to a method and an apparatus for manufacturing a peeling container. In a second injection molding step in which a second layer is laminated on the inner peripheral side of a first layer of a bottomed cylindrical preform, a second resin material is guided from an opening formed in the first layer toward the inner peripheral side of the first layer, and an engagement portion protruding from the opening is formed on the outer peripheral side of the first layer so as to be integrated with the second layer.

Description

[0001] This application is a divisional application of the original PCT international application filed on April 6, 2021, which entered the Chinese national phase with application number 202180030109.8 and the invention title "Method and apparatus for manufacturing a stripping container". Technical Field

[0002] This invention relates to a method and apparatus for manufacturing a stripping container. Background Technology

[0003] Previously, a type of resin-based release container was known, which had a double-layered structure with an inner and outer layer, the inner layer gradually peeling off from the outer layer as the contents were discharged. This type of release container was also called a layered bottle or vacuum bottle, and was used, for example, as a container for condiments such as soy sauce or cosmetic liquids.

[0004] Currently, in the manufacturing of such peelable containers, extrusion blow molding is commonly used, while stretch blow molding is less frequently used (see Patent Document 1).

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 5267901 Summary of the Invention The problem that the invention aims to solve For example, from the perspective of improving the appearance, dimensional accuracy, and physical strength of the release container, and reducing the environmental impact by suppressing unnecessary materials, the application of a hot preform blow molding method in the manufacture of release containers, which involves a one-step process from injection molding to blow molding, is being studied.

[0006] However, in most cases, the melting point of the resin material used for the outer layer of the release container is set higher than that of the resin material used for the inner layer. In the injection molding process of forming a preform with a double-layer structure, if the high-temperature resin material of the outer layer is filled after the inner layer has been formed, the surface of the inner layer in contact with the outer resin material will melt and undergo thermal deformation. Therefore, it is extremely difficult to manufacture the release container itself using a hot preform blow molding method.

[0007] Furthermore, if the fusion properties between the outer and inner layers in the preform of the release container are low, unexpected separation or displacement of the outer and inner layers may occur. For example, if the inner layer is fixed to the mandrel and rolled up when the mandrel inserted into the double-layer preform is pulled out, unexpected separation or displacement of the outer layer may occur. Additionally, for example, it is also possible that during blow molding of the double-layer preform, the inner and outer layers slide against each other, resulting in displacement of the outer and inner layers, and the release container is formed in this state.

[0008] Therefore, the present invention was made in view of such a problem, and its object is to provide a manufacturing method that can suppress accidental separation and positional displacement of the outer and inner layers when manufacturing a release container using a hot preform blow molding method.

[0009] Technical solutions for solving the problem A method for manufacturing a release container according to one aspect of the present invention includes: a first injection molding step in which a first layer of a bottomed cylindrical preform is injection molded using a first resin material; a second injection molding step in which a second resin material different from the first resin material is injected and a second layer is laminated on the inner circumferential side of the first layer; and a blow molding step in which the preform obtained by the second injection molding step is blow molded in a state of being heated during injection molding to manufacture a release container. In the second injection molding step, the second resin material is guided from an opening formed in the first layer toward the inner circumferential side of the first layer, and a locking portion bulging out from the opening is integrally formed on the outer circumferential side of the first layer and the second layer.

[0010] Invention Effects According to one aspect of the present invention, when manufacturing a release container using a hot preform blow molding method, it is possible to suppress accidental separation and positional displacement of the outer and inner layers. Attached Figure Description

[0011] Figure 1 This is a longitudinal sectional view of the preform of the first embodiment.

[0012] Figure 2 This is a longitudinal sectional view of the peeling container according to the first embodiment.

[0013] Figure 3 This is a diagram schematically showing the structure of the blow molding apparatus of the first embodiment.

[0014] Figure 4 This is a diagram showing the manufacturing process of the preform according to the first embodiment.

[0015] Figure 5 (a) is a view showing the area near the bottom of the first layer in the first injection molding section of the first embodiment, and (b) is a view showing the area near the bottom of the preform in the second injection molding section of the first embodiment.

[0016] Figure 6 This is a perspective view showing an example of the structure of the second cavity mold of the first injection molding part.

[0017] Figure 7 This is a flowchart illustrating the process of manufacturing a stripping container.

[0018] Figure 8 This is a longitudinal sectional view of the preform of the second embodiment.

[0019] Figure 9 This is a diagram showing the manufacturing process of the preform according to the second embodiment.

[0020] Figure 10 (a) is a view showing the area near the bottom of the first layer in the first injection molding section of the second embodiment, and (b) is a view showing the area near the bottom of the preform in the second injection molding section of the second embodiment. Detailed Implementation

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0022] In the embodiments, for ease of understanding and explanation, structures and elements other than the main parts of the invention are simplified or omitted in the description. Furthermore, in the accompanying drawings, the same elements are labeled with the same reference numerals. Additionally, the shapes, dimensions, etc., of the elements shown in the drawings are schematic representations and do not represent actual shapes, dimensions, etc.

[0023] (First Embodiment) <Structural Example of a Preform> First, refer to Figure 1 This section describes a structural example of the pre-plasticized blank for the peeling container according to the first embodiment. Figure 1 This is a longitudinal sectional view of the preform 10 according to the first embodiment. The preform 10 has an overall shape of a bottomed cylindrical shape with an opening at one end and a closed end. The preform 10 includes: a main body portion 14 formed in a cylindrical shape, a bottom portion 15 that closes the other end of the main body portion 14, and a neck portion 13 with an opening formed at one end of the main body portion 14.

[0024] The preform 10 has a double-layer structure in which a second layer (inner layer) 12 is laminated inside a first layer (outer layer) 11. The first layer 11 and the second layer 12 are formed using different thermoplastic resin materials through a two-stage injection molding process, as described later. The first layer 11 is made of a synthetic resin with excellent moldability and transparency. On the other hand, the second layer 12 is made of a synthetic resin with properties that can stably retain the contents of the container and inhibit deterioration (oxidation) (e.g., moisture resistance, gas barrier properties, heat resistance, and chemical resistance). Furthermore, the resin material for the first layer 11 is selected to have a higher melting point than the resin material for the second layer 12.

[0025] Hereinafter, the resin material of the first layer 11 will also be referred to as the first resin material, and the resin material of the second layer 12 will also be referred to as the second resin material.

[0026] The combination of the first and second resin materials can be appropriately selected according to the specifications of the peeling container. Specific types of materials include, for example, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexanediol terephthalate), Tritan (Tritan (registered trademark): a copolyester manufactured by Eastman Chemical Company), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPSU (polyphenylsulfone), PS (polystyrene), COP / COC (cyclic olefin polymer), PMMA (polymethyl methacrylate; acrylic acid), PLA (polylactic acid), etc.

[0027] As an example, the first resin material is PET (polyethylene terephthalate), and the second resin material is PP (polypropylene). PP has a melting point of 160~170℃, while PET has a higher melting point of 245~260℃.

[0028] Furthermore, in the main body 14 of the preform 10, the ratio (t1 / t2) of the thickness t1 of the first layer 11 to the thickness t2 of the second layer 12 is preferably 1.5 or more. From the viewpoint of ensuring the transparency of the release container to be formed, this thickness ratio is preferably 3.0 or less.

[0029] Furthermore, in the bottom 15 of the preform 10, an opening 16 is formed through the center of the bottom of the first layer 11. The opening 16 of the first layer 11 is blocked from the inside by the second layer 12. On the outside of the first layer 11, the second layer 12 has a locking portion 19 that bulges radially outward from the opening 16. The locking portion 19 can be formed in a ring shape along the periphery of the opening 16, or multiple portions can be formed at intervals in the circumferential direction.

[0030] Additionally, a recess 17 for forming an air inlet hole in the peeling container is formed on the bottom 15 of the preform 10. The recess 17 may have a circular cross-section, and at least one recess is formed radially spaced from the center of the bottom 15 of the preform 10; however, multiple recesses 17 may be formed along the circumference of the bottom 15. The depth of the recess 17 in the thickness direction of the preform is set such that at least one recess 17 penetrates the first layer 11, exposing the surface of the second layer 12 within the recess 17. Furthermore, the recess 17 formed in the double-layered preform 10 may be distinguished from the recess formed only in the first layer 11 (described later) and referred to as a second recess. Additionally, the cross-section of the recess 17 may be elliptical, polygonal, slit-shaped, or a combination thereof, other than circular.

[0031] <Example of a peeling container structure> Next, refer to Figure 2The following describes a structural example of the resin-made peeling container 20 according to the first embodiment. Figure 2 This is a longitudinal sectional view of the stripping container 20 according to the first embodiment.

[0032] The release container 20 is a bottle-shaped resin container obtained by stretch blow molding a preform 10, for example, for holding condiments such as soy sauce. Furthermore, the release container 20 can also be used to hold other contents such as cosmetic liquids.

[0033] Like the preform 10, the release container 20 has a double-layer structure in which a second layer 12 is stacked inside the first layer 11. In the main body 22 of the release container 20, the ratio of the thickness t11 of the first layer 11 to the thickness t12 of the second layer 12 (t11 / t12) is almost the same as the ratio of the thicknesses in the main body 14 of the preform 10 (t1 / t2).

[0034] The release container 20 has: a neck 21 with an opening at the upper end, a cylindrical body portion 22 continuous from the neck 21, and a bottom portion 23 continuous from the body portion 22. In the manufacture of the release container 20, the body portion 14 and bottom portion 15 of the preform 10 are expanded by stretch blow molding, thereby being shaped into the body portion 22 and bottom portion 23 of the release container 20. Furthermore, during stretch blow molding, the preform 10 is stretched through the recess 17, thereby forming an air inlet hole 24 through which the first layer 11 passes in the bottom portion 23 of the release container 20.

[0035] In the peeling container 20, contents are filled into the space inside the second layer 12. In the peeling container 20, as the contents are discharged from the second layer 12, air gradually flows into the space between the first layer 11 and the second layer 12 through the air inlet 24, causing the first layer 11 and the second layer 12 to gradually peel apart. Thus, without allowing the contents of the second layer 12 to come into contact with air, the volume occupied by the contents within the container is replaced with air, and the contents filled into the second layer 12 can be discharged out of the container.

[0036] Furthermore, similar to the preform 10, an opening 25 (non-laminated, single-layer portion) penetrating the first layer 11 is formed at the center of the bottom 23 of the peeling container 20. The material of the second layer 12 fills the opening 25 by blocking it, resulting in the second layer 12 being exposed outside the first layer 11 near the opening 25 of the bottom 23 of the peeling container 20. Additionally, a locking portion 26 (bulge 26) for the second layer 12 is formed at the bottom 23 of the peeling container 20, bulging radially outward from the opening 25 of the first layer 11. The locking portion 26 is formed by stretching the locking portion 19 of the preform 10. By exposing the second layer 12 outside the first layer 11 at the opening 25 of the peeling container 20, the second layer 12 is partially fixed to the first layer 11, and positional displacement of the second layer 12 relative to the first layer 11 is suppressed.

[0037] <Description of the manufacturing apparatus for the stripping container> Figure 3 This is a schematic diagram showing the structure of the blow molding apparatus 30 of the first embodiment. The blow molding apparatus 30 of the first embodiment is an example of a manufacturing apparatus for a release container 20, which employs a hot preform method (also called a one-step method) to blow mold the release container 20 without cooling the preform 10 to room temperature and effectively utilizing the heat retained during injection molding (internal heat).

[0038] The blow molding apparatus 30 includes a first injection molding unit 31, a first temperature adjustment unit 32, a second injection molding unit 33, a second temperature adjustment unit 34, a blow molding unit 35, a take-out unit 36, and a conveying mechanism 37. The first injection molding unit 31, the first temperature adjustment unit 32, the second injection molding unit 33, the second temperature adjustment unit 34, the blow molding unit 35, and the take-out unit 36 ​​are positioned at a position that rotates by the same predetermined angle (e.g., 60 degrees) around the conveying mechanism 37 each time. Alternatively, the blow molding apparatus 30 may be configured to omit the first temperature adjustment unit 32 (in which case, each molding station is positioned at a position that rotates by 72 degrees around the conveying mechanism 37 each time). Furthermore, a core mold lifting mechanism (not shown) is provided above the conveying mechanism 37 in the first injection molding unit 31 and the second injection molding unit 33.

[0039] (Conveying mechanism 37) Conveying mechanism 37 is equipped with Figure 3 A rotating plate (transfer plate) 37a rotates around an axis perpendicular to the paper surface. On the rotating plate 37a, a neck mold 37b holds the neck 13 (or the neck 21 of the peeling container 20) of the preform 10. Figure 3(Not shown in the diagram) One or more are arranged at predetermined angles. The conveying mechanism 37, by rotating the rotating plate 37a, sequentially conveys the preform 10 (or stripping container 20) held by the neck mold 37b to the first injection molding section 31, the first temperature adjustment section 32, the second injection molding section 33, the second temperature adjustment section 34, the blow molding section 35, and the take-off section 36. In addition, the conveying mechanism 37 can also raise and lower the rotating plate 37a, and also perform the actions involved in mold closing and mold opening (demolding) in the first injection molding section 31 and the second injection molding section 33.

[0040] (First Injection Molding Section 31) The first injection molding unit 31 includes a cavity mold 40, a core mold 41, and a hot runner mold 42, and cooperates with the neck mold 37b conveyed during molding to manufacture the first layer 11 of the preform 10. The cavity mold 40 is composed of a first cavity mold 40A on the opening side (upper side) and a second cavity mold 40B on the bottom side (lower side). A first injection device 38 that supplies the first resin material to the hot runner mold 42 is connected to the first injection molding unit 31. The cavity mold 40 and the hot runner mold 42 are fixed to the machine base of the blow molding apparatus 30 in an integrated state. The core mold 41 is fixed to the core mold lifting mechanism.

[0041] Figure 4 (a) and (b) show the first injection molding section 31 that shapes the first layer 11 of the preform 10 of the first embodiment. Figure 5 (a) is a diagram showing the area near the bottom of the first layer 11 in the first injection molding section 31 of the first embodiment. Figure 6 (a) is a perspective view showing a structural example of the cavity mold 40 (second cavity mold 40B) of the first injection molding part 31.

[0042] Cavity mold 40 defines the shape of the outer periphery of the first layer 11. First cavity mold 40A is the mold facing the opening side of cavity mold 40 (the side that abuts against neck mold 37b when closed), defining the shape of the outer periphery of the main body of the first layer 11. Second cavity mold 40B is the mold facing the bottom side of cavity mold 40 (the side that abuts against hot runner mold 42), defining the shape of the bottom outer periphery of the first layer 11. Second cavity mold 40B also includes a gate portion 40Ba for guiding resin material from hot runner mold 42 to the cavity surface. Additionally, hot runner mold 42 has a resin supply portion 42a (resin flow path 42a) for introducing the first resin material, plasticized (molten) in the first injection device 38, into second cavity mold 40B. Core mold 41 is the mold defining the shape of the inner periphery of the first layer 11, inserted from above into the inner periphery of cavity mold 40. The neck mold 37b specifies the shape of the neck 13 of the preform 10 (first layer 11).

[0043] like Figure 4As shown in (a) and (b), in the first injection molding section 31, the cavity mold 40, the core mold 41, and the neck mold 37b of the conveying mechanism 37 are closed to form a mold space for the first layer 11. Then, by allowing the first resin material to flow in from the bottom of the mold space through the hot runner mold 42, the first layer 11 of the preform 10 is manufactured in the first injection molding section 31.

[0044] On the upper surface (cavity side) of the second cavity mold 40B facing the bottom outer periphery of the first layer 11, a first protrusion 44, which is cylindrical, conical cylindrical, or prismatic, is provided at a predetermined position. For example... Figure 6 As shown in (a), at least one first protrusion 44 is arranged radially spaced from the center of the bottom where the resin supply portion 42a is located. Figure 5 As shown in (a), the protrusion h1 of the first protrusion 44 from the cavity reference surface of the second cavity mold 40B (the cavity surface that defines the shape of the lower end of the bottom outer peripheral surface of the first layer 11) is approximately the same as the thickness of the first layer 11. Therefore, when the first injection molding section 31 is closed, the top end of the first protrusion 44 faces the surface of the core mold 41 (located near the surface of the core mold 41). Thus, during the injection molding of the first injection molding section 31, a circular or other recess 11a is formed in the first layer 11 at a position corresponding to the recess 17 of the preform 10 via the first protrusion 44. The recess 11a of the first layer 11 can either penetrate the first layer 11 or have a thin film formed by the core mold 41 and the first protrusion 44. Furthermore, the recess 11a of the first layer 11 formed by the first injection molding section 31 is also referred to as the first recess.

[0045] In addition, such as Figure 4 As shown in (b), a valve pin (a rod-shaped component for opening and closing the resin supply section 42a) 43 is provided in the resin supply section 42a of the hot runner mold 42, which can move axially upwards to a position close to the core mold 41. The valve pin 43 is housed inside the hot runner mold 42 before the first resin material is filled into the mold space, and after the first resin material is filled into the mold space, it protrudes to a position closer to the core mold 41 than the cavity-side opening end of the gate section 40Ba. Through this movement of the valve pin 43 during injection molding, a thin film portion 18 of resin material with a wall thickness thinner than the peripheral portion can be formed at the bottom center of the first layer 11.

[0046] Furthermore, when the first injection molding section 31 is opened, the neck mold 37b of the conveying mechanism 37 remains closed and is kept in place to convey the first layer 11 of the preform 10. The number of preforms 10 simultaneously formed by the first injection molding section 31 (i.e., the number of release containers 20 that can be simultaneously formed by the blow molding device 30) can be appropriately set.

[0047] (First temperature adjustment unit 32) The first temperature adjustment unit 32 includes a temperature adjustment mold (not shown) for adjusting the temperature of the first layer 11 from the outside, and a heating rod, temperature adjustment rod, or air inlet rod for adjusting the temperature of the first layer 11 from the inside. The first temperature adjustment unit 32 cools (or heats) the first layer 11, which is in a high-temperature state after injection molding, by placing it in the temperature adjustment mold and maintaining it at a predetermined temperature. In addition, the first temperature adjustment unit 32 also functions to adjust the temperature distribution of the first layer 11 to a predetermined state before it is conveyed to the second injection molding unit 33.

[0048] (Second Injection Molding Section 33) The second injection molding unit 33 includes a cavity mold 50, a core mold 51, and a hot runner mold 52. It cooperates with the neck mold 37b, which is conveyed during molding, to injection mold the second layer 12 onto the inner circumferential side of the first layer 11. The cavity mold 50 is composed of a first cavity mold 50A on the opening side (upper side) and a second cavity mold 50B on the bottom side (lower side). A second injection device 39 is connected to the second injection molding unit 33 to supply the second resin material to the hot runner mold 52.

[0049] Figure 4 (c) shows the second injection molding section 33 that shapes the second layer 12 of the preform 10. Figure 5 (b) is a diagram showing the area near the bottom of the preform 10 in the second injection molding section 33.

[0050] Cavity mold 50 is a mold that houses the first layer 11. First cavity mold 50A is the mold facing the opening side of cavity mold 50, housing the main body of the first layer 11. Second cavity mold 50B is the mold facing the bottom side of cavity mold 50, housing the bottom of the first layer 11. Second cavity mold 50B also includes a gate portion 50Ba for guiding resin material from hot runner mold 52 to the cavity surface. Additionally, hot runner mold 52 has a resin supply portion 52a (resin flow path 52a) at the center of its bottom for introducing the second resin material plasticized (molten) in the second injection device 39. Core mold 51 is a mold that defines the shape of the inner circumference of the second layer 12, inserted from above into the inner circumference of cavity mold 50. Neck mold 37b defines the upper end face (top surface) of the neck 13 of the preform 10 (second layer 12). Furthermore, hot runner mold 52 can also have a valve pin structure like hot runner mold 42. However, the position of the valve pin when the second resin material is sealed is set to a position that does not protrude beyond the opening end on the cavity side of the gate portion 50Ba.

[0051] like Figure 4As shown in (c), the second injection molding section 33 houses the first layer 11 of the preform 10 after injection molding through the first injection molding section 31. With the second injection molding section 33 closed, a mold space is formed between the inner circumferential side of the first layer 11 and the surface of the core mold 51. In the second injection molding section 33, by allowing the second resin material to flow in from the bottom of the mold space via the hot runner mold 52, a preform 10 with a second layer 12 stacked on the inner circumferential side of the first layer 11 is formed.

[0052] Furthermore, on the upper surface (cavity side) of the second cavity mold 50B facing the bottom outer periphery of the first layer 11, a second protrusion 54, such as a cylinder, corresponding to the shape of the recess 17 of the preform 10, is provided at a predetermined position corresponding to the first protrusion 44 of the first injection molding part 31. When the second injection molding part 33 is received in the first layer 11, the second protrusion 54 is inserted into the recess 11a of the first layer 11. Thus, the basic structure of the protrusion, etc., in the second cavity mold 50B is almost the same as that of the second cavity mold 40B of the first injection molding part 31.

[0053] Here, as Figure 5 As shown in (b), the protrusion h2 of the second protrusion 54 from the cavity reference surface of the second cavity mold 50B (the cavity surface that abuts against the lower end side region of the bottom outer peripheral surface of the first layer 11) is a dimension larger than the thickness of the first layer 11. That is, the protrusion h2 of the second protrusion 54 is larger than the protrusion h1 of the first protrusion 44 (h2>h1). Therefore, when the second injection molding section 33 is closed, the top end of the second protrusion 54 penetrates the recess 11a of the first layer 11 and protrudes to the inner peripheral side of the first layer 11. By providing the second protrusion 54 in the second cavity mold 50B of the second injection molding section 33, a recess 17 can be formed in the bottom 15 of the preform 10.

[0054] Furthermore, the protrusion amount h2 of the second protrusion 54 is set to be smaller than the thickness of the preform 10. That is, during injection molding in the second injection molding section 33, the second resin material flows between the core mold 51 and the second protrusion 54, so a hole that penetrates the second layer 12 will not be formed due to the second protrusion 54.

[0055] In addition, such as Figure 5 As shown in (b), in the cavity mold 50, the cavity end 53 connected to the gate portion 50Ba has a curved, expanded diameter portion (bulge) that expands toward the mold space. Therefore, near the center of the bottom of the second injection molding portion 33, a gap is created between the curved surface of the cavity end 53 of the cavity mold 50 and the outer peripheral surface of the first layer 11. During injection molding, the second resin material flows into this gap. Consequently, on the outer side of the first layer 11, a locking portion 19, bulging radially outward from the opening 16, can be integrally formed with the second layer 12.

[0056] (Second temperature adjustment unit 34) The second temperature adjustment unit 34 includes a temperature adjustment mold unit (not shown) for adjusting the temperature of the preform 10 from the outside (a heating tank or temperature adjustment tank (temperature regulating tank) and a heating rod, temperature regulating rod (temperature regulating rod) or air inlet rod for adjusting the temperature of the preform 10 from the inside). The second temperature adjustment unit 34 adjusts the temperature of the preform 10 to a temperature suitable for final blow molding (e.g., about 90°C to 105°C) by homogenizing and removing temperature deviations of the preform 10 conveyed from the second injection molding unit 33 by housing it in the mold unit and maintaining it at a predetermined temperature. In addition, the second temperature adjustment unit 34 also has the function of cooling the preform 10 in a high-temperature state after injection molding.

[0057] (Blow molding section 35) The blow molding section 35 blow molds the pre-plasticized preform 10 after the temperature is adjusted by the second temperature adjustment section 34 to manufacture the release container 20.

[0058] The blow molding section 35 includes a pair of parting dies corresponding to the shape of the release container 20, namely a blow molding cavity mold, a bottom mold, a stretching rod, and an air inlet component (all not shown). The blow molding section 35 performs blow molding while stretching the pre-plasticized preform 10. Thus, the pre-plasticized preform 10 can be shaped into the shape of the blow molding cavity mold to manufacture the release container 20.

[0059] (Removal section 36) The removal section 36 is configured to open the neck 21 of the release container 20 manufactured by the blow molding section 35 from the neck mold 37b, and remove the release container 20 to the outside of the blow molding apparatus 30.

[0060] <Description of the container manufacturing method> Next, the manufacturing method of the stripping container 20 based on the blow molding apparatus 30 of the first embodiment will be described. Figure 7 This is a flowchart illustrating the process of manufacturing the stripping container 20.

[0061] (Step S101: First injection molding process) First, such as Figure 4 As shown in (a), in the first injection molding section 31, the first resin material is injected from the first injection device 38 into the mold space formed by the cavity mold 40, the core mold 41 and the neck mold 37b, and the first layer 11 of the preform 10 is formed. At this time, a recess 11a is formed at the bottom of the first layer 11 through the first protrusion 44.

[0062] In the first injection molding section 31, such as Figure 4As shown in (b), after the first layer 11 of the preform 10 is formed, a process is performed to make the valve pin 43 protrude to a position close to the core mold 41. As a result, a thin film portion 18 with a wall thickness thinner than the periphery is formed at the bottom center of the first layer 11.

[0063] Then, the first injection molding section 31 is opened to demold the first layer. When the first injection molding section 31 is opened, the rotating plate 37a of the conveying mechanism 37 rotates by a predetermined angle, and the first layer 11 of the preform 10 held in the neck mold 37b is conveyed to the first temperature adjustment section 32 while retaining heat during injection molding.

[0064] (Step S102: First temperature adjustment process) Next, in the first temperature adjustment section 32, the first layer 11 of the preform 10 is housed in a temperature adjustment mold, and the first layer 11 is cooled and its temperature distribution is adjusted (equalization and removal of temperature deviation). Alternatively, the first temperature adjustment process can be omitted.

[0065] After the first temperature adjustment process (or the first injection molding process), the rotating plate 37a of the conveying mechanism 37 rotates by a predetermined angle, and the first layer 11, which is held in the neck mold 37b after temperature adjustment, is conveyed to the second injection molding section 33.

[0066] (Step S103: Second injection molding process) Next, the second layer 12 is injection molded in the first layer 11 of the preform 10 housed in the second injection molding section 33.

[0067] In the second injection molding section 33, such as Figure 4 As shown in (c), a mold space is formed between the inner circumferential side of the first layer 11 and the surface of the core mold 51 facing the inner circumference of the first layer 11, and a second resin material is filled into the mold space from the hot runner mold 52. Furthermore, although a thin film portion 18 is formed at the bottom of the first layer 11, the thin film portion 18 ruptures due to the injection pressure of the second resin material, forming an opening 16 at the bottom, and the second resin material is guided from the opening 16 to the inner circumferential side of the first layer 11.

[0068] Here, the temperature of the second resin material filled in the second injection molding section 33 is set to a temperature lower than the melting point of the first resin material. In addition, the surface temperature of the first layer 11 when the second resin material is filled in the second injection molding section 33 is cooled to a temperature below the melting point of the second resin material.

[0069] In the second injection molding section 33, the cavity mold 50 faces the outer peripheral side of the first layer 11, and the shape of the first layer 11 is maintained from the outer peripheral side by the cavity mold 50. Therefore, even if the second resin material comes into contact with the first layer 11, thermal deformation of the first layer 11 can be suppressed.

[0070] Furthermore, in the second injection molding section 33, the second protrusion 54 penetrates and blocks the recess 11a of the first layer 11, so the recess 17 of the preform 10 is not blocked by the second resin material. In addition, the top of the second protrusion 54 in the second injection molding section 33 protrudes to the inner circumference of the first layer, so the recess 17 of the preform 10 formed by the second protrusion 54 has a shape that penetrates the first layer 11 and exposes the surface of the second layer 12 within the recess 17.

[0071] Furthermore, in the second injection molding section 33, by allowing the second resin material to flow into the gap between the curved surface of the cavity end 53 adjacent to the gate portion 50Ba of the cavity mold 50B and the outer peripheral surface of the first layer 11, a locking portion 19 is integrally formed on the outer side of the first layer 11 and the second layer 12. By locking the second layer 12 on the outer side of the first layer 11 with the locking portion 19, it is prevented from falling off relative to the first layer 11.

[0072] As described above, a preform 10 with a second layer 12 stacked on the inner periphery of the first layer 11 is manufactured through the first injection molding process and the second injection molding process.

[0073] Subsequently, when the second injection molding section 33 opens the mold, the rotating plate 37a of the conveying mechanism 37 rotates by a predetermined angle, and the preform 10 held in the neck mold 37b is conveyed to the second temperature adjustment section 34 while retaining heat during injection molding.

[0074] (Step S104: Second temperature adjustment process) Next, in the second temperature adjustment unit 34, the preform 10 is housed in the temperature adjustment mold unit, and temperature adjustment is performed to bring the temperature of the preform 10 close to the temperature suitable for final blow molding. Afterward, the rotating plate 37a of the conveying mechanism 37 rotates by a predetermined angle, and the temperature-adjusted preform 10 held in the neck mold 37b is conveyed to the blow molding unit 35.

[0075] (Step S105: Blow molding process) Next, in the blow molding section 35, the release container 20 is blow molded.

[0076] First, the blow molding cavity is closed, housing the preform 10 within the mold space. An air inlet component (blow molding core) is lowered, bringing it into contact with the neck 13 of the preform 10. Then, a stretching bar is lowered, pressing down on the bottom 15 of the preform 10 from the inside, stretching it longitudinally as needed, and supplying the blow molding core from the air inlet component, thereby stretching the preform 10 transversely. As a result, the preform 10 bulges and is shaped to fit tightly against the mold space of the blow molding cavity, blow-molding it into a release container 20.

[0077] (Step S106: Container removal process) After blow molding is completed, the blow molding cavity mold is opened. As a result, the release container 20 can be moved from the blow molding section 35.

[0078] Next, the rotating plate 37a of the conveying mechanism 37 rotates by a predetermined angle, and the peeling container 20 is conveyed to the take-out section 36. In the take-out section 36, the neck 21 of the peeling container 20 opens from the neck mold 37b, and the peeling container 20 is taken out of the blow molding apparatus 30.

[0079] This concludes one cycle of the method for manufacturing the release container. Afterwards, by rotating the rotating plate 37a of the conveying mechanism 37 by a predetermined angle, the aforementioned steps S101 to S106 are repeated. Furthermore, while the blow molding apparatus 30 is operating, the manufacturing of six sets of release containers 20, each with a time difference of one step, is performed in parallel.

[0080] Furthermore, in the structure of the blow molding apparatus 30, the standby time for the first injection molding process, the first temperature adjustment process, the second injection molding process, the second temperature adjustment process, the blow molding process, and the container removal process is the same length. Similarly, the conveying time between each process is also the same length.

[0081] The effects of the blow molding apparatus and blow molding method of the first embodiment will be described below.

[0082] In the first embodiment, the first layer 11 (outer layer) of the preform 10 is molded in the first injection molding step, and the second layer 12 (inner layer) is injection molded from the opening 16 of the first layer 11 inside the first layer 11 in the second injection molding step to produce a preform 10 with a double-layer structure. According to the first embodiment, the outer layer can be formed first using a resin material with a high melting point, and then the inner layer can be formed using a resin material with a lower melting point than the outer layer. That is, the inner layer can be continuously injection molded while the outer layer is in a state of heat retention during injection molding, thereby producing a preform 10 with a double-layer structure suitable for the specifications of the release container 20. In the first embodiment, since the preform 10 with a double-layer structure is demolded while both the outer and inner layers are in a state of heat retention during injection molding, a suitable preform 10 can be obtained when manufacturing the release container 20 using a hot preform blow molding method.

[0083] Furthermore, in the first embodiment, the release container 20 is manufactured by stretch blow molding the preform 10 with the double-layer structure while it is still hot from injection molding. Therefore, in the first embodiment, a release container 20 with a beautiful appearance and excellent physical properties such as strength can be manufactured using a hot preform blow molding method. Compared to cold preform blow molding, in the first embodiment, it is not necessary to cool the manufactured preform 10 to near room temperature, nor is a reheating process for the preform 10 required. Therefore, according to the first embodiment, a series of processes from injection molding of the preform 10 to blow molding of the release container 20 can be completed in a shorter time, enabling the release container 20 to be manufactured in a shorter cycle.

[0084] In addition, in the first embodiment, during the second injection molding process, a locking portion 19 is integrally formed on the outer side of the first layer 11 by the second resin material forming the second layer 12, to prevent the second layer 12 from falling off relative to the first layer 11.

[0085] Therefore, when a pulling force is applied to the second layer 12 toward the neck, the locking part 19 abuts against the first layer 11, thus resisting the pulling force, making it difficult for the outer and inner layers of the preform 10 to separate. Therefore, in the first embodiment, it is possible to suppress accidental separation and positional displacement of the outer and inner layers during processes such as core mold pulling in the second injection molding process or blow molding, thereby improving the yield rate of the release container 20.

[0086] (Second Implementation) Next, the second embodiment will be described. In the following description, elements identical to those in the first embodiment described above will be labeled with the same reference numerals, and all repeated descriptions will be omitted.

[0087] For example, when molding a preform with a double-layer structure, if the outer layer is molded first and then the inner layer is molded, and the resin material of the inner layer is accidentally wrapped around to the outer periphery and covers the outside of the preform, the aesthetics of the blow-molded container will be greatly compromised.

[0088] In the second embodiment, a structure is described to prevent the resin material of the inner layer from accidentally wrapping around to the outer periphery when manufacturing a release container using a hot preform blow molding method.

[0089] Figure 8 This is a longitudinal sectional view of the pre-plasticized preform 10 according to the second embodiment. The following is a description... Figure 1 The differences between the pre-plasticized preform 10 of the first embodiment and that of the second embodiment are shown. Figure 8The bottom 15 of the preform 10 of the second embodiment shown has a raised portion 12a that protrudes in a curved shape toward the inner periphery of the second layer 12. The raised portion 12a is formed by resin accumulation during the injection molding of the second resin material and is located opposite the opening 16 of the first layer 11.

[0090] Furthermore, since the structure of the peeling container 20 in the second embodiment is the same as that in the first embodiment, repeated descriptions are omitted.

[0091] Furthermore, the basic structure of the blow molding apparatus 30 in the second embodiment is the same as... Figure 3 The blow molding apparatus 30 shown in the first embodiment is the same. Hereinafter, the differences in the second embodiment will be explained.

[0092] Figure 9 This is a diagram showing the manufacturing process of the preform according to the second embodiment. Figure 10 (a) is a diagram showing the area near the bottom of the first layer in the first injection molding section of the second embodiment. Figure 10 (b) is a diagram showing the area near the bottom of the preform in the second injection molding section of the second embodiment. Figure 9 Corresponding to the first embodiment Figure 4 , Figure 10 Corresponding to the first embodiment Figure 5 .

[0093] In the first injection molding section 31 of the second embodiment, as Figure 9 As shown in (a), the axial length of the inner periphery of the cavity mold 40, which corresponds to the bottom surface of the main body of the first layer 11, is set to L1.

[0094] Additionally, in the second injection molding section 33 of the second embodiment, such as Figure 9 As shown in (c), the axial length (depth) of the inner periphery of the cavity mold 50, which houses the upper end of the main body of the first layer 11 to the bottom surface, is set to L2 (L1>L2), which is shorter than L1. For example, L2 is set to be shorter than L1 by the amount of deformation of the first layer 11 (the amount of compression of the first layer 11 caused by the upward push of the cavity mold 50 or the amount of shrinkage of the first layer 11 due to heat dissipation, etc., before the second injection molding process). In other words, the depth of the mold space of the cavity mold 50 housing the first layer 11 is shorter than the axial length of the first layer 11.

[0095] In addition, such as Figure 9 (c) Figure 10As shown in (b), a curved recess 51a is formed at the top of the core mold 51 in the second embodiment. When the mold is closed, the recess 51a faces the outlet of the second resin material located at the center of the second cavity mold 50B, forming a space for resin accumulation between it and the opening 16 of the first layer 11. Through this resin accumulation, a raised portion 12a is formed on the inner peripheral side of the second layer 12.

[0096] In addition, such as Figure 10 As shown in (b), for example, in the second injection molding section 33 of the second embodiment, the diameter d2 (diameter of the valve pin) of the top end of the hot runner mold 52 is set to be smaller than the diameter d1 of the opening 16 of the first layer 11 and the diameter of the top end of the hot runner mold 42 of the first injection molding section 31 (diameter of the valve pin 43). By narrowing the diameter d2 of the top end of the hot runner mold 52 to be smaller than the diameter d1 of the opening 16, the flow rate of the second resin material injected into the mold space of the second injection molding section 33 can be increased.

[0097] The manufacturing process of the stripping container 20 in the second embodiment is as follows: Figure 7 As shown, the process includes a first injection molding process (S101), a first temperature adjustment process (S102), a second injection molding process (S103), a second temperature adjustment process (S104), a blow molding process (S105), and a container removal process (S106). The first injection molding process (S101) and the first temperature adjustment process (S102) in the second embodiment are the same as those in the first embodiment.

[0098] In the second injection molding process (S103) of the second embodiment, the second layer 12 is injection molded in the first layer 11 of the preform 10 housed in the second injection molding section 33.

[0099] In the second injection molding section 33, such as Figure 9 As shown in (c), a mold space is formed between the inner circumferential side of the first layer 11 and the surface of the core mold 51 facing the inner circumference of the first layer 11, and a second resin material is filled into the mold space from the hot runner mold 52. Furthermore, although a thin film portion 18 is formed at the bottom of the first layer 11, the thin film portion 18 ruptures due to the injection pressure of the second resin material, forming an opening 16 at the bottom, and the second resin material is guided from the opening 16 to the inner circumferential side of the first layer 11.

[0100] As described above, the depth of the mold space of the cavity mold 50 that houses the first layer 11 is shorter than the axial length of the first layer 11. Therefore, when the first layer 11 is housed in the cavity mold 50, the bottom of the first layer 11 is pushed against the bottom surface of the cavity mold 50 to make them contact each other, which can suppress the generation of gaps between the bottom of the first layer 11 and the cavity mold 50.

[0101] Furthermore, a resin accumulation space is formed between the opening 16 of the first layer 11 and the recess 51a of the core mold 51. The second resin material passing through the opening 16 impacts the recess 51a of the core mold 51 and is stirred within the resin accumulation space before flowing into the mold space between the inner periphery of the first layer 11 and the surface of the core mold 51. By stirring the second resin material within the resin accumulation space, fragments of the film portion 18 of the first layer 11 mix and dissolve with the high-temperature second resin material. This allows the fragments of the film portion 18 to dissipate to a level that is no longer visually apparent.

[0102] Furthermore, the diameter d2 of the top of the hot runner mold 52 is narrowed to be smaller than the diameter d1 of the opening 16 of the first layer 11. By increasing the flow rate of the second resin material from the top of the hot runner mold 52 to the recess 51a, sufficient agitation of the second resin material is generated in the resin accumulation space, making it easier to dissipate fragments of the film portion 18. Moreover, it is easier to break the film portion 18.

[0103] Furthermore, a portion of the second resin material, after impacting the recess 51a, is guided outwards through the opening 16 towards the first layer 11, circulating near the opening 16. This flow also agitates the second resin material, promoting the dissipation of debris from the film portion 18.

[0104] Here, the temperature of the second resin material filled in the second injection molding section 33 is set to a temperature lower than the melting point of the first resin material. In addition, the surface temperature of the first layer 11 when the second resin material is filled in the second injection molding section 33 is cooled to a temperature below the melting point of the second resin material.

[0105] In the second injection molding section 33, the cavity mold 50 faces the outer peripheral side of the first layer 11, and the shape of the first layer 11 is maintained from the outer peripheral side by the cavity mold 50. Therefore, even if the second resin material comes into contact with the first layer 11, thermal deformation of the first layer 11 can be suppressed.

[0106] Furthermore, in the second injection molding section 33, the second protrusion 54 penetrates and blocks the recess 11a of the first layer 11, so the recess 17 of the preform 10 will not be blocked by the second resin material. In addition, the tip of the second protrusion 54 in the second injection molding section 33 protrudes to the inner circumference of the first layer, so the recess 17 of the preform 10 formed by the second protrusion 54 has a shape that penetrates the first layer 11 and exposes the surface of the second layer 12 into the recess 17.

[0107] As described above, a preform 10 with a second layer 12 stacked on the inner periphery of the first layer 11 is manufactured through the first injection molding process and the second injection molding process.

[0108] Subsequently, when the second injection molding section 33 opens, the rotating plate 37a of the conveying mechanism 37 rotates by a predetermined angle, and the preform 10 held in the neck mold 37b is conveyed to the second temperature adjustment section 34 while retaining heat during injection molding.

[0109] Furthermore, the second temperature adjustment process (S104), blow molding process (S105), and container removal process (S106) of the second embodiment are the same as those of the first embodiment.

[0110] The effects of the blow molding apparatus and blow molding method of the second embodiment will be explained below.

[0111] In the second embodiment, in the second injection molding section 33, the depth of the mold space of the cavity mold 50 that houses the first layer 11 is shorter than the axial length of the first layer 11. Therefore, the bottom of the first layer 11 is pushed against the bottom surface of the cavity mold 50, suppressing the formation of a gap between the bottom of the first layer 11 and the cavity mold 50. Thus, according to this embodiment, the second resin material is less likely to flow into the space between the first layer 11 and the cavity mold 50, suppressing molding defects such as the second resin material covering the outer periphery of the first layer 11.

[0112] Furthermore, in the second embodiment, by providing a recessed portion 51a at the top of the core mold 51, the fragments of the film portion 18 are stirred and dissolved with the high-temperature second resin material during injection molding, making it easier for the fragments of the film portion 18 to dissipate. As a result, the possibility of aesthetic damage due to the fragments of the film portion 18 remaining in the inner layer can be reduced in the preform 10 and the release container 20.

[0113] This invention is not limited to the above-described embodiments. Various improvements and design changes can be made without departing from the spirit of this invention.

[0114] In the above embodiment, an example is described in which a recess 17 is provided at the bottom 15 of the pre-plasticized blank 10, but for example, the number of recesses 17 can also be multiple. Figure 6 (b) shows an example in which two first protrusions 44 are provided in the second cavity mold 40B of the first injection molding section 31. Figure 6 In example (b), the two first protrusions 44 are spaced 180° apart and arranged in a point-symmetrical position with respect to the central axis. Furthermore, the number of first protrusions 44 can be three or more. In this case, each first protrusion 44 is preferably arranged in a point-symmetrical position with respect to the central axis.

[0115] According to the above structure, circumferential unevenness in the flow of resin during injection molding is reduced. Furthermore, in the case of the above structure, in the second injection molding section 33, the second protrusion 54 also needs to be positioned at the same location as the first protrusion 44.

[0116] Furthermore, it should be considered that the embodiments disclosed herein are illustrative rather than restrictive in all respects. The scope of the invention is set forth in the claims rather than in the foregoing description, and is intended to include all modifications of the same meaning and scope as the claims.

[0117] Explanation of reference numerals in the attached figures 10…Pre-plastic preform, 11…First layer, 11a…Recess, 12…Second layer, 16…Opening, 17…Recess, 18…Film part, 19, 26…Catching part, 20…Peeling container, 24…Air inlet hole, 30…Blow molding device, 31…First injection molding part, 33…Second injection molding part, 35…Blow molding part, 38…First injection device, 39…Second injection device, 40B, 50B…Cavity mold, 44…First protrusion, 54…Second protrusion.

Claims

1. A method for manufacturing a peeling container, comprising: In the first injection molding process, the first layer of the bottomed cylindrical preform is injection molded using the first resin material. In the second injection molding process, a second resin material different from the first resin material is injected, and the second layer is laminated on the inner peripheral side of the first layer; and The blow molding process involves blow molding the preform obtained from the second injection molding process while retaining the heat from the injection molding process to manufacture a release container. In the second injection molding process, the first layer is housed in the mold space of the first mold and the second mold is inserted into the interior of the first layer. The second resin material is then injected between the first layer and the second mold. The depth of the mold space of the first mold is shorter than the axial length of the first layer obtained through the first injection molding process.

2. The method for manufacturing the stripping container according to claim 1, wherein, In the first injection molding process, a thin-walled film portion is formed in a part of the first layer. In the second injection molding process, the second resin material is guided to the inner peripheral side of the first layer through the opening formed by the rupture of the film portion.

3. The method for manufacturing the stripping container according to claim 2, wherein, In the second mold, a recess is formed at the location opposite the injection port of the second resin material.

4. The method for manufacturing the stripping container according to claim 3, wherein, In the second injection molding process, the size of the injection port of the second resin material is smaller than the size of the opening of the first layer formed by the rupture of the film portion.

5. The method for manufacturing the stripping container according to any one of claims 1 to 4, wherein, The melting point of the first resin material is higher than that of the second resin material.

6. An apparatus for manufacturing a peeling container, comprising: The first injection molding section uses the first resin material to injection mold the first layer of the bottomed cylindrical preform. The second injection molding section injects a second resin material different from the first resin material, and stacks the second layer on the inner peripheral side of the first layer; and The blow molding section blow molds the pre-plasticized preform obtained from the second injection molding section while retaining the heat from the injection molding process to manufacture a release container. The second injection molding unit has a first mold for housing the first layer in a mold space and a second mold for inserting into the interior of the first layer, and injects the second resin material between the first layer and the second mold. The depth of the mold space of the first mold is shorter than the axial length of the first layer obtained through the first injection molding section.

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