Method for manufacturing a peel container and manufacturing device

Abstract

The present application relates to a manufacturing method and a manufacturing apparatus of a peelable container. The manufacturing method of the peelable container includes a second injection molding process of laminating a second layer on an inner peripheral side of a first layer of a bottomed tubular pre-molded blank, guiding a second resin material from an opening portion formed in the first layer to the inner peripheral side of the first layer, and integrally forming a locking portion protruding from the opening portion on the outer peripheral side of the first layer with the second layer.

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method and manufacturing apparatus for a peelable container. BACKGROUND

[0002] Conventionally, a peelable container made of resin has been known, which has a double-layer structure of an inner layer and an outer layer, and the inner layer is gradually peeled from the outer layer according to discharge of contents. Such a peelable container is also called a layered bottle or a vacuum bottle, and is utilized as a container for a seasoning liquid such as soy sauce, a cosmetic liquid, and the like.

[0003] At present, in the manufacturing of such a peelable container, an extrusion blow molding method is generally used, and a stretch blow molding method is less used (see Patent Document 1).

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent No. 5267901 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] For example, from the viewpoint of improving the appearance, dimensional accuracy, physical strength, and the like of the peelable container, reducing environmental load by suppressing unnecessary materials, and the like, a blow molding method of the hot parison type, which continuously performs from an injection molding step to a blow molding step in one step, is being studied for application to the manufacturing of the peelable container.

[0009] However, in most cases, the melting point of the resin material for the outer layer of the peelable container is set higher than the melting point of the resin material for the inner layer. In the injection molding step of molding the pre-plastic parison of the double-layer structure, if the resin material for the outer layer at a high temperature is filled after the inner layer is formed, the surface of the inner layer that contacts the resin material for the outer layer is melted and thermally deformed. Thus, it is extremely difficult to manufacture the peelable container by applying the blow molding method of the hot parison type.

[0010] In addition, if the wettability of the outer layer and the inner layer is low in the pre-plastic parison of the peelable container, unexpected separation and positional displacement of the outer layer and the inner layer can occur. For example, if the inner layer is stuck to the core mold and is rolled up when the core mold inserted into the pre-plastic parison of the double-layer structure is pulled out, unexpected separation and positional displacement of the outer layer can occur. In addition, for example, a phenomenon in which the inner layer and the outer layer slide with respect to each other and the peelable container is molded in a state where the positional displacement of the outer layer and the inner layer has occurred can occur when the pre-plastic parison of the double-layer structure is blow molded.

[0011] Thus, the present application has been achieved in view of such problems, and has an object to provide a manufacturing method capable of suppressing unexpected separation and positional deviation of an outer layer from an inner layer when a peelable container is manufactured by applying a hot parison type blow molding method.

[0012] Technical solution for solving the problems

[0013] The manufacturing method of the peelable container according to one aspect of the present application includes a first injection molding step of injection molding a first layer of a bottomed tubular pre-plastic parison using a first resin material, a second injection molding step of injection molding a second layer on an inner peripheral side of the first layer using a second resin material different from the first resin material, and a blow molding step of blow molding the pre-plastic parison obtained by the second injection molding step in a state where heat remaining at the time of injection molding is retained, to manufacture the peelable container. In the second injection molding step, the second resin material is guided from an opening portion formed in the first layer to the inner peripheral side of the first layer, and a locking portion protruding from the opening portion is integrally formed with the second layer on an outer peripheral side of the first layer.

[0014] Effects of the invention

[0015] According to one aspect of the present application, when a peelable container is manufactured by applying a hot parison type blow molding method, it is possible to suppress unexpected separation and positional deviation of an outer layer from an inner layer. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a longitudinal sectional view of a pre-plastic parison of the first embodiment.

[0017] Figure 2 is a longitudinal sectional view of a peelable container of the first embodiment.

[0018] Figure 3 is a diagram schematically showing a structure of a blow molding device of the first embodiment.

[0019] Figure 4 is a diagram showing a manufacturing step of a pre-plastic parison of the first embodiment.

[0020] Figure 5 (a) is a diagram showing a vicinity of a bottom of a first layer in a first injection molding portion of the first embodiment, and (b) is a diagram showing a vicinity of a bottom of a pre-plastic parison in a second injection molding portion of the first embodiment.

[0021] Figure 6 is a perspective view showing a structure example of a second cavity mold of the first injection molding portion.

[0022] Figure 7 is a flowchart showing a step of a manufacturing method of a peelable container.

[0023] Figure 8It is a longitudinal sectional view of a preform according to the second embodiment.

[0024] Figure 9 It is a figure which shows the manufacturing process of the preform in 2nd Embodiment.

[0025] Figure 10 (a) is a diagram showing the vicinity of the bottom of the first layer in the first injection molded portion of the second embodiment, and (b) is a diagram showing the vicinity of the bottom of the preform in the second injection molded portion of the second embodiment. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0027] In the embodiments, for ease of understanding, the structures and elements other than the essential parts of the present invention are simplified or omitted for illustration. In the accompanying drawings, identical elements are denoted by the same reference numerals. Furthermore, the shapes, dimensions, etc. of the elements shown in the accompanying drawings are schematic and do not represent actual shapes, dimensions, etc.

[0028] (First embodiment)

[0029] <Example of the structure of the preform>

[0030] First, refer to Figure 1 , a structural example of a preform for a peelable container according to the first embodiment will be described. Figure 1 This is a longitudinal cross-sectional view of a preform 10 according to the first embodiment. The overall shape of the preform 10 is a bottomed cylinder with one end open and the other closed. The preform 10 includes a cylindrical body 14, a bottom 15 that closes the other end of the body 14, and a neck 13 that is open at one end of the body 14.

[0031] The preform 10 has a two-layer structure in which a second layer (inner layer) 12 is laminated on the inner side of a first layer (outer layer) 11. The first layer 11 and the second layer 12 are formed from different thermoplastic resin materials by two-stage injection molding, as described below. The first layer 11 is formed from a synthetic resin having excellent moldability and transparency. On the other hand, the second layer 12 is formed from a synthetic resin having properties (e.g., moisture resistance, gas barrier properties, heat resistance, and chemical resistance) that allow the contents of the container to be stably stored and inhibits degradation (oxidation). 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.

[0032] Hereinafter, the resin material of the first layer 11 is also referred to as a first resin material, and the resin material of the second layer 12 is also referred to as a second resin material.

[0033] The combination of the first and second resin materials can be appropriately selected depending on the specifications of the peelable container. Specific examples of the materials include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexanedimethylene 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 polymers), PMMA (polymethyl methacrylate; acrylic acid), and PLA (polylactic acid).

[0034] For example, the first resin material is PET (polyethylene terephthalate) and the second resin material is PP (polypropylene). The melting point of PP is about 160-170°C, while the melting point of PET is higher than that of PP, about 245-260°C.

[0035] 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 greater. From the perspective of ensuring the transparency of the peelable container to be molded, this thickness ratio is preferably 3.0 or less.

[0036] Furthermore, in the bottom portion 15 of the preform 10, an opening 16 is formed at the center of the bottom portion of the first layer 11, penetrating 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 protrudes radially outward from the opening 16. The locking portion 19 may be formed in an annular shape along the periphery of the opening 16, or may be formed in a plurality at intervals in the circumferential direction.

[0037] Furthermore, a recess 17 is formed in the bottom 15 of the preform 10 to form an air inlet hole in the peeling container. Recess 17 may have a circular cross-section, for example, and may be formed at least once 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 recess 17 in the thickness direction of the preform is set to a dimension sufficient to allow recess 17 to penetrate the first layer 11 and expose the surface of the second layer 12 within recess 17. Furthermore, recess 17 formed in the two-layer preform 10 may be distinguished from recesses formed only in the first layer 11 (described later) and referred to as second recesses. Furthermore, the cross-section of recess 17 may be elliptical, polygonal, slit-shaped, or a combination thereof, in addition to a circular shape.

[0038] <Example of the structure of the peelable container>

[0039] Next, refer to Figure 2 , a structural example of the resin peelable container 20 according to the first embodiment will be described. Figure 2 It is a longitudinal sectional view of the peelable container 20 of the first embodiment.

[0040] The peelable container 20 is a bottle-shaped resin container obtained by stretch-blow molding the preform 10, and is used to store, for example, a seasoning liquid such as soy sauce.

[0041] Like the preform 10, the peelable container 20 has a two-layer structure in which the second layer 12 is laminated on the inner side of the first layer 11. In the main body 22 of the peelable 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 substantially the same as the ratio of the thicknesses (t1 / t2) in the main body 14 of the preform 10.

[0042] The peelable container 20 includes a neck portion 21 having an opening at its upper end, a cylindrical body portion 22 continuous from the neck portion 21, and a bottom portion 23 continuous from the body portion 22. During the manufacture of the peelable 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 peelable container 20. Furthermore, during the stretch blow molding, the recessed portion 17 of the preform 10 is stretched, thereby forming an air inlet hole 24 penetrating the first layer 11 in the bottom portion 23 of the peelable container 20.

[0043] In the peelable container 20, the space inside the second layer 12 is filled with the contents. In the peelable container 20, as the contents are discharged from the second layer 12, air gradually flows through the air inlet holes 24 into the space between the first layer 11 and the second layer 12, gradually separating the first layer 11 and the second layer 12. This allows the volume occupied by the contents within the container to be replaced with air without allowing the contents of the second layer 12 to come into contact with air, allowing the contents filled in the second layer 12 to be discharged from the container.

[0044] In addition, similar to the preform 10, an opening 25 (non-laminated portion, single-layer portion) is formed at the center of the bottom 23 of the peelable container 20, penetrating the first layer 11. The material of the second layer 12 is filled into the opening 25 so as to block the opening 25, so that the second layer 12 is exposed outside the first layer 11 near the opening 25 of the bottom 23 of the peelable container 20. Furthermore, a locking portion 26 (bulging portion 26) of the second layer 12 is formed at the bottom 23 of the peelable 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 peelable container 20, the second layer 12 is partially fixed to the first layer 11, thereby suppressing positional displacement of the second layer 12 relative to the first layer 11.

[0045] <Description of the Peelable Container Manufacturing Apparatus>

[0046] Figure 3 This figure schematically shows the structure of a blow molding device 30 according to the first embodiment. The blow molding device 30 according to the first embodiment is an example of an apparatus for manufacturing a peelable container 20. It adopts a hot parison method (also called a one-step method) in which the preform 10 is blow-molded into the peelable container 20 by effectively utilizing the heat retained during injection molding (internal heat) without cooling the preform 10 to room temperature.

[0047] The blow molding apparatus 30 includes a first injection molding section 31, a first temperature regulating section 32, a second injection molding section 33, a second temperature regulating section 34, a blow molding section 35, a take-out section 36, and a conveying mechanism 37. The first injection molding section 31, the first temperature regulating section 32, the second injection molding section 33, the second temperature regulating section 34, the blow molding section 35, and the take-out section 36 are arranged at positions rotated by the same predetermined angle (e.g., 60 degrees) about the conveying mechanism 37. Alternatively, the blow molding apparatus 30 may be configured to omit the first temperature regulating section 32 (in which case, each molding station is arranged at a position rotated by 72 degrees about the conveying mechanism 37). Furthermore, a core mold lifting mechanism (not shown) is provided above the conveying mechanism 37 in the first and second injection molding sections 31 and 33.

[0048] (Conveying mechanism 37)

[0049] The conveying mechanism 37 has Figure 3 A rotating plate (transfer plate) 37a is provided which rotates about an axis perpendicular to the paper surface. On the rotating plate 37a, a neck mold 37b (in the Figure 3(Not shown) One or more of these are arranged at predetermined angles. The conveying mechanism 37 rotates the rotating plate 37a to sequentially convey the preform 10 (or peeling 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 removal section 36. Furthermore, the conveying mechanism 37 is capable of raising and lowering the rotating plate 37a and also performs operations related to mold closing and mold opening (mold removal) in the first injection molding section 31 and the second injection molding section 33.

[0050] (First Injection Molded Part 31)

[0051] The first injection molding section 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 produce 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). The first injection molding section 31 is connected to the first injection device 38 that supplies the first resin material to the hot runner mold 42. The cavity mold 40 and the hot runner mold 42 are fixed to the machine table of the blow molding device 30 in an integrated state. The core mold 41 is fixed to the core mold lifting mechanism.

[0052] Figure 4 (a) and (b) show the first injection molded portion 31 that molds the first layer 11 of the preform 10 according to the first embodiment. Figure 5 (a) is a diagram showing the vicinity of the bottom of the first layer 11 in the first injection molded part 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 molded part 31 .

[0053] The cavity mold 40 defines (defines) the shape of the outer periphery of the first layer 11. The first cavity mold 40A is a mold facing the opening side of the cavity mold 40 (the side that abuts the neck mold 37b when the mold is closed), and defines the shape of the outer periphery of the main body of the first layer 11. The second cavity mold 40B is a mold facing the bottom side of the cavity mold 40 (the side that abuts the hot runner mold 42), and defines the shape of the bottom outer periphery of the first layer 11. The second cavity mold 40B also has a gate portion 40Ba that guides the resin material from the hot runner mold 42 to the cavity surface. In addition, the hot runner mold 42 has a resin supply portion 42a (resin flow path 42a) that introduces the first resin material plasticized (melted) in the first injection device 38 to the second cavity mold 40B. The core mold 41 is a mold that defines the shape of the inner periphery of the first layer 11 and is inserted from the upper side to the inner periphery of the cavity mold 40. The neck mold 37b defines the outer shape of the neck 13 of the preform 10 (first layer 11).

[0054] like Figure 4As shown in (a) and (b) of FIG, 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, the first resin material is flowed from the bottom of the mold space through the hot runner mold 42 to produce the first layer 11 of the preform 10 in the first injection molding section 31.

[0055] On the upper surface side (cavity surface side) of the second cavity mold 40B facing the bottom periphery of the first layer 11, a first protrusion 44 in a cylindrical, tapered cylindrical or prism shape is provided at a predetermined position. Figure 6 As shown in (a), at least one first protrusion 44 is arranged at intervals in the radial direction from the center of the bottom where the resin supply portion 42a is located. Figure 5 As shown in (a), the amount h1 by which the first protrusion 44 protrudes from the cavity reference surface (the cavity surface that defines the lower end shape of the bottom outer peripheral surface of the first layer 11) of the second cavity mold 40B is approximately the same as the thickness of the first layer 11. Therefore, when the first injection molded part 31 is closed, the tip of the first protrusion 44 faces the surface of the core mold 41 (is located near the surface of the core mold 41). Thus, during the injection molding of the first injection molded part 31, the first protrusion 44 forms a circular or other concave portion 11a in the first layer 11 at a position corresponding to the concave portion 17 of the preform 10. The concave portion 11a of the first layer 11 may penetrate the first layer 11 or may comprise a thin film sandwiched between the core mold 41 and the first protrusion 44. Furthermore, the concave portion 11a of the first layer 11 formed by the first injection molded part 31 is also referred to as the first concave portion.

[0056] In addition, if Figure 4 As shown in (b), a valve pin (a rod-shaped member that opens and closes the resin supply portion 42a) 43 is provided in the resin supply portion 42a of the hot runner mold 42, capable of axial movement until it approaches the core mold 41. Before the first resin material is filled into the mold space, the valve pin 43 is housed within the hot runner mold 42. After the first resin material has been filled into the mold space, the valve pin 43 protrudes to a position closer to the core mold 41 than the cavity-side opening of the gate portion 40Ba. This movement of the valve pin 43 during injection molding allows the formation of a thin film portion 18 of resin material at the bottom center of the first layer 11, where the wall thickness is thinner than that of the surrounding portions.

[0057] Furthermore, when the first injection molding section 31 is opened, the neck mold 37b of the conveying mechanism 37 is not opened, but is held and conveyed while the first layer 11 of the preforms 10 is held. The number of preforms 10 that can be simultaneously molded by the first injection molding section 31 (that is, the number of peelable containers 20 that can be simultaneously molded by the blow molding device 30) can be appropriately set.

[0058] (First Temperature Adjustment Unit 32)

[0059] The first temperature adjustment unit 32 includes a temperature adjustment mold (not shown) (a heating tank or a temperature adjustment tank (temperature adjustment tank) for adjusting the temperature of the first layer 11 from the outside, and a heating rod, a temperature adjustment rod (temperature adjustment rod) or an air introduction 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 accommodating it in a temperature adjustment mold maintained at a predetermined temperature. In addition, the first temperature adjustment unit 32 also has the function of adjusting the temperature distribution of the first layer 11 to a predetermined state before conveying it to the second injection molding unit 33.

[0060] (Second injection molded portion 33)

[0061] 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 transported during molding, to injection mold the second layer 12 on the inner circumference 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). The second injection molding unit 33 is connected to a second injection device 39 that supplies the second resin material to the hot runner mold 52.

[0062] Figure 4 (c) shows the second injection molded portion 33 that molds the second layer 12 of the preform 10 . Figure 5 (b) is a diagram showing the vicinity of the bottom of the preform 10 in the second injection molding section 33 .

[0063] The cavity mold 50 is a mold that houses the first layer 11. The first cavity mold 50A is a mold facing the opening side of the cavity mold 50 and houses the main body of the first layer 11. The second cavity mold 50B is a mold facing the bottom side of the cavity mold 50 and houses the bottom of the first layer 11. The second cavity mold 50B also has a gate portion 50Ba that guides the resin material from the hot runner mold 52 to the cavity surface. In addition, the hot runner mold 52 has a resin supply portion 52a (resin flow path 52a) at the center of the bottom to introduce the second resin material plasticized (melted) in the second injection device 39. The core mold 51 is a mold that defines the shape of the inner circumference of the second layer 12 and is inserted from the upper side into the inner circumference of the cavity mold 50. The neck mold 37b defines the upper end surface (top surface) of the neck 13 of the preform 10 (second layer 12). In addition, the hot runner mold 52 can also be a structure with a valve pin like the 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 from the opening end of the gate portion 50Ba on the cavity side.

[0064] like Figure 4As shown in (c) of FIG, the second injection molding section 33 accommodates the first layer 11 of the preform 10 injection-molded by the first injection molding section 31. When the second injection molding section 33 is closed, a mold space is formed between the inner circumference of the first layer 11 and the surface of the core mold 51. In the second injection molding section 33, the second resin material flows from the bottom of the mold space through the hot runner mold 52, forming a preform 10 in which the second layer 12 is laminated on the inner circumference of the first layer 11.

[0065] Furthermore, on the upper surface (cavity surface) of the second cavity mold 50B, which faces the outer periphery of the bottom portion of the first layer 11, a second protrusion 54, such as a cylindrical shape, 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 molded part 31. The second protrusion 54 is inserted into the recess 11a of the first layer 11 when the first layer 11 is accommodated in the second injection molded part 33. Thus, the basic structure of the protrusion and the like in the second cavity mold 50B is substantially the same as that of the second cavity mold 40B of the first injection molded part 31.

[0066] Here, if Figure 5 As shown in (b), the amount h2 by which the second protrusion 54 protrudes from the cavity reference surface of the second cavity mold 50B (the cavity surface that contacts the lower end region of the bottom outer peripheral surface of the first layer 11) is greater than the thickness of the first layer 11. In other words, the amount h2 of protrusion 54 protrudes is greater than the amount h1 of protrusion 44 protrudes (h2 > h1). Therefore, when the second injection-molded part 33 is closed, the tip 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. Providing the second protrusion 54 in the second cavity mold 50B of the second injection-molded part 33 allows the recess 17 to be formed in the bottom 15 of the preform 10.

[0067] 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 that the second protrusion 54 does not form a hole that penetrates the second layer 12.

[0068] In addition, if Figure 5 As shown in (b), in the cavity mold 50, the cavity end portion 53 connected to the gate portion 50Ba is formed with a curved expanded diameter portion (bulging portion) that expands toward the mold space. Therefore, near the center of the bottom of the second injection molded portion 33, a gap is generated between the curved surface of the cavity end portion 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 the above-mentioned gap. As a result, on the outside of the first layer 11, a locking portion 19 that bulges radially outward from the opening portion 16 can be formed integrally with the second layer 12.

[0069] (Second Temperature Adjustment Unit 34)

[0070] The second temperature adjustment section 34 includes a mold unit (not shown) for temperature adjustment (a heating tank or a temperature adjustment tank (temperature regulating tank) for adjusting the temperature of the preform 10 from the outside, and a heating rod, a temperature adjustment rod (temperature regulating rod) or an air introduction rod for adjusting the temperature of the preform 10 from the inside). The second temperature adjustment section 34 equalizes the temperature of the preform 10 conveyed from the second injection molding section 33 and eliminates temperature deviations by accommodating the preform 10 in a mold unit maintained at a predetermined temperature, thereby adjusting the temperature of the preform 10 to a temperature suitable for final blow molding (e.g., approximately 90°C to 105°C). In addition, the second temperature adjustment section 34 also has the function of cooling the preform 10 in a high-temperature state after injection molding.

[0071] (Blow molding section 35)

[0072] The blow molding section 35 blow-moldes the preform 10 whose temperature has been adjusted by the second temperature adjustment section 34 , thereby manufacturing the peelable container 20 .

[0073] The blow molding unit 35 includes a pair of split molds corresponding to the shape of the peelable container 20, namely, a blow cavity mold, a bottom mold, a stretch rod, and an air introduction member (none of which are shown). The blow molding unit 35 performs blow molding while stretching the preform 10. This allows the preform 10 to be shaped into the shape of the blow cavity mold to produce the peelable container 20.

[0074] (Removal portion 36)

[0075] The take-out unit 36 ​​is configured to open the neck portion 21 of the peelable container 20 manufactured by the blow molding unit 35 from the neck mold 37 b and take the peelable container 20 out of the blow molding device 30 .

[0076] <Description of Container Manufacturing Method>

[0077] Next, a method for manufacturing the peelable container 20 using the blow molding device 30 according to the first embodiment will be described. Figure 7 1 is a flowchart showing the steps of a method for manufacturing the peelable container 20 .

[0078] (Step S101: First Injection Molding Process)

[0079] First, if Figure 4 As shown in FIG. 5 (a), in the first injection molding section 31, a first resin material is injected from the first injection unit 38 into the mold space formed by the cavity mold 40, the core mold 41, and the neck mold 37b, thereby molding the first layer 11 of the preform 10. At this time, a recessed portion 11a is formed at the bottom of the first layer 11 by the first protrusion 44.

[0080] In the first injection molding part 31, as Figure 4 As shown in (b), after the first layer 11 of the preform 10 is formed, the valve pin 43 is protruded to a position close to the core mold 41. As a result, a thin film portion 18 having a thinner wall thickness than the peripheral portion is formed at the bottom center of the first layer 11.

[0081] After that, the first injection molding section 31 is opened to release 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 control section 32 while retaining the heat from the injection molding process.

[0082] (Step S102: First Temperature Adjustment Step)

[0083] Next, in the first temperature adjustment section 32, the first layer 11 of the preform 10 is accommodated in a temperature adjustment mold, and the first layer 11 is cooled and its temperature distribution is adjusted (temperature uniformization and temperature deviation elimination).

[0084] After the first temperature adjustment step (or the first injection molding step), the rotating plate 37 a of the conveying mechanism 37 rotates by a predetermined angle, and the temperature-adjusted first layer 11 held by the neck mold 37 b is conveyed to the second injection molding unit 33 .

[0085] (Step S103: Second Injection Molding Process)

[0086] Next, the first layer 11 of the preform 10 is accommodated in the second injection molding section 33 , and the second layer 12 is injection-molded.

[0087] In the second injection molded portion 33, as shown in FIG. Figure 4 As shown in (c), a mold space is formed between the inner circumference of the first layer 11 and the surface of the core mold 51 facing the inner circumference of the first layer 11, and the second resin material is filled into the above-mentioned mold space from the hot runner mold 52. In addition, although a thin film portion 18 is formed at the bottom of the first layer 11, the injection pressure of the second resin material causes the thin film portion 18 to rupture and form an opening 16 at the bottom. The second resin material is guided from the above-mentioned opening 16 to the inner circumference of the first layer 11.

[0088] Here, the temperature of the second resin material filled in the second injection molded portion 33 is set to a temperature lower than the melting point of the first resin material. In addition, when the second resin material is filled in the second injection molded portion 33, the surface temperature of the first layer 11 is cooled to a temperature below the melting point of the second resin material.

[0089] In the second injection molded portion 33, the cavity mold 50 faces the outer periphery of the first layer 11, and the shape of the first layer 11 is maintained from the outer periphery by the cavity mold 50. Therefore, even if the second resin material contacts the first layer 11, thermal deformation of the first layer 11 can be suppressed.

[0090] Furthermore, in the second injection molded portion 33, the second protrusions 54 penetrate and block the recesses 11a of the first layer 11, thereby preventing the recesses 17 of the preform 10 from being blocked by the second resin material. Furthermore, since the tips of the second protrusions 54 in the second injection molded portion 33 protrude toward the inner circumference of the first layer, the recesses 17 of the preform 10 formed by the second protrusions 54 have a shape that penetrates the first layer 11 and exposes the surface of the second layer 12 within the recesses 17.

[0091] Furthermore, in the second injection molded portion 33, the second resin material flows into the gap between the curved surface of the cavity end portion 53 adjacent to the gate portion 50Ba of the cavity mold 50B and the outer peripheral surface of the first layer 11, thereby forming a locking portion 19 integrally with the second layer 12 outside the first layer 11. The locking portion 19 is locked outside the first layer 11, thereby preventing the second layer 12 from falling off relative to the first layer 11.

[0092] As described above, the preform 10 in which the second layer 12 is laminated on the inner peripheral side of the first layer 11 is manufactured through the first injection molding step and the second injection molding step.

[0093] Thereafter, when the second injection molding section 33 is opened, 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 regulating section 34 while retaining the heat from the injection molding.

[0094] (Step S104: Second Temperature Adjustment Process)

[0095] Next, in the second temperature adjustment section 34, the preform 10 is received in the temperature adjustment mold unit and temperature adjustment is performed to bring the temperature of the preform 10 close to a temperature suitable for final blow molding. Thereafter, the rotating plate 37a of the conveying mechanism 37 rotates a predetermined angle, and the temperature-adjusted preform 10 held in the neck mold 37b is conveyed to the blow molding section 35.

[0096] (Step S105: Blow Molding Process)

[0097] Next, in the blow molding section 35 , the peelable container 20 is blow-molded.

[0098] First, the blow cavity mold is closed to house the preform 10 in the mold space, and the air introduction member (blow pin) is lowered so that the air introduction member abuts against the neck portion 13 of the preform 10. Then, the stretch rod is lowered to press the bottom portion 15 of the preform 10 from the inner face, longitudinal axis stretching is performed as necessary, and the blow pin is supplied from the air introduction member, whereby the preform 10 is subjected to transverse axis stretching. Thus, the preform 10 is blown out in a manner to tightly adhere to the mold space of the blow cavity mold, and is shaped into the peeled container 20.

[0099] (Step S106: container taking-out process)

[0100] When the blow molding is completed, the blow cavity mold is opened. Thus, the peeled container 20 can be moved from the blow molding portion 35.

[0101] Next, the rotating plate 37a of the conveyance mechanism 37 is rotated by a predetermined angle, and the peeled container 20 is conveyed toward the taking-out portion 36. In the taking-out portion 36, the neck portion 21 of the peeled container 20 is opened from the neck mold 37b, and the peeled container 20 is taken out to the outside of the blow molding device 30.

[0102] Thus, one cycle in the manufacturing method of the peeled container is completed. Thereafter, the above-described processes S101 to S106 are repeatedly performed by rotating the rotating plate 37a of the conveyance mechanism 37 by a predetermined angle. Further, during the operation of the blow molding device 30, the manufacturing of six sets of the peeled containers 20 having a time difference of one process each is performed in parallel.

[0103] In addition, in the blow molding device 30, the standby times of 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 taking-out process are each made the same length. Also, the conveyance times between the processes are each made the same length.

[0104] Hereinafter, the effects of the blow molding device and the blow molding method of the first embodiment will be described.

[0105] In the first embodiment, a first layer 11 (outer layer) of a preform 10 is molded in a first injection molding step, and a second layer 12 (inner layer) is injection molded inside the first layer 11 through the opening 16 of the first layer 11 in a second injection molding step, thereby producing a two-layer preform 10. According to the first embodiment, the outer layer can be formed first using a resin material with a higher melting point, and then the inner layer can be formed using a resin material with a lower melting point than the outer layer. In other words, the inner layer can be continuously injection molded while the outer layer remains hot during injection molding, thereby producing a two-layer preform 10 suitable for the specifications of a peelable container 20. In the first embodiment, since the two-layer preform 10 is demolded while both the outer and inner layers remain hot during injection molding, a suitable preform 10 can be obtained when manufacturing a peelable container 20 using a hot parison blow molding method.

[0106] Furthermore, in the first embodiment, the preform 10 having the above-described two-layer structure is stretch-blow molded while still hot from injection molding to produce the peelable container 20. Thus, in the first embodiment, a peelable container 20 having a beautiful appearance and excellent physical strength can be produced using a hot-parison blow molding method. Compared to cold-parison blow molding, the first embodiment eliminates the need to cool the produced preform 10 to near room temperature, nor does it require a reheating step. Therefore, according to the first embodiment, the series of steps from injection molding of the preform 10 to blow molding of the peelable container 20 can be completed in a shorter time, enabling the peelable container 20 to be produced in a shorter cycle.

[0107] Furthermore, in the first embodiment, in the second injection molding step, the 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 , thereby preventing the second layer 12 from falling off relative to the first layer 11 .

[0108] Thus, when a force in the pulling direction acts on the second layer 12 toward the neck, the locking portion 19 contacts the first layer 11, resisting the pulling force, and thus preventing the outer layer and the inner layer of the preform 10 from shifting. Therefore, in the first embodiment, it is possible to suppress unintended separation or positional shifting of the outer layer and the inner layer, for example, during the pulling of the core mold in the second injection molding step or during the blow molding step, thereby improving the yield rate of the peelable container 20.

[0109] (Second embodiment)

[0110] In the following description, the same elements as those in the first embodiment are denoted by the same reference numerals, and any duplicate descriptions are omitted.

[0111] For example, in the case where the outer layer is molded first and then the inner layer is molded in molding a preform of a double-layered structure, if the resin material of the inner layer filled afterward unexpectedly goes around to the outer peripheral side to cover the outside of the preform, the appearance of the container after blow molding will be greatly damaged.

[0112] In the second embodiment, a structure for suppressing molding defects in which the resin material of the inner layer unexpectedly goes around to the outer peripheral side when a hot preform type blow molding method is applied to manufacture a peel container is described.

[0113] Figure 8 is a longitudinal sectional view of the preform 10 of the second embodiment. Hereinafter, the differences between the preform 10 of the first embodiment and the second embodiment are described. Figure 1 The preform 10 of the first embodiment shown in FIG. 1 is different from the second embodiment. In the second embodiment, the preform 10 is formed by the first injection molding section 31 and the second injection molding section 33. Figure 8 The bottom 15 of the preform 10 of the second embodiment shown in FIG. 2 is formed with a protruding portion 12a that protrudes in a curved shape toward the inner peripheral side of the second layer 12. The protruding portion 12a is a resin accumulation formed at the time of injection molding of the second resin material, and is formed at a position opposite to the opening portion 16 of the first layer 11.

[0114] Further, since the structure of the peel container 20 in the second embodiment is the same as that of the first embodiment, the repeated description is omitted.

[0115] In addition, the basic structure of the blow molding apparatus 30 of the second embodiment is the same as that of the first embodiment shown in FIG. 3. Hereinafter, the differences in the second embodiment are described. Figure 3

[0116] Figure 9 is a view showing the manufacturing process of the preform of the second embodiment. Figure 10 (a) of FIG. 4 is a view showing the vicinity of the bottom of the first layer in the first injection molding section of the second embodiment, Figure 10 (b) of FIG. 4 is a view showing the vicinity of the bottom of the preform in the second injection molding section of the second embodiment. Figure 9 Corresponding to the first embodiment of Figure 4 , Figure 10 Corresponding to the first embodiment of Figure 5 .

[0117] In the first injection molding section 31 of the second embodiment, as shown in (a) of FIG. 4, the axial length of the inner peripheral portion of the cavity mold 40 corresponding to the first layer 11 from the upper end of the main body portion to the bottom surface is set to L1. Figure 9

[0118] In addition, in the second injection molding section 33 of the second embodiment, as shown in (a) of FIG. 5, the axial length of the inner peripheral portion of the cavity mold 40 corresponding to the second layer 12 from the upper end of the main body portion to the bottom surface is set to L2. Figure 9 ​​As shown in (c), the axial length (depth) of the inner circumference of the cavity mold 50 from the upper end of the main body portion to the bottom surface that accommodates the first layer 11 is set to L2, which is shorter than L1 (L1>L2). For example, L2 is set to be shorter than L1 by the 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 before the second injection molding step). In other words, the depth of the mold space of the cavity mold 50 that accommodates the first layer 11 is shorter than the axial length of the first layer 11.

[0119] In addition, if Figure 9 (c) Figure 10 As shown in FIG. 5( b ), a curved recessed portion 51 a is formed at the tip of the core mold 51 in the second embodiment. When the mold is closed, the recessed portion 51 a faces the outlet of the second resin material located at the center of the second cavity mold 50B, and forms a space for resin accumulation between the recessed portion 51 a and the opening 16 of the first layer 11. This resin accumulation forms a raised portion 12 a on the inner circumference of the second layer 12.

[0120] In addition, if Figure 10 As shown in (b), for example, in the second injection molded part 33 of the second embodiment, the diameter d2 of the tip of the hot runner mold 52 (the diameter of the valve pin) is set to be smaller than the diameter of the tip of the hot runner mold 42 of the first injection molded part 31 (the diameter of the valve pin 43) and the diameter d1 of the opening 16 of the first layer 11. By narrowing the diameter d2 of the tip 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 molded part 33 can be increased.

[0121] The steps of the method for manufacturing the peelable container 20 in the second embodiment are as follows: Figure 7 As shown, the second embodiment includes a first injection molding step (S101), a first temperature adjustment step (S102), a second injection molding step (S103), a second temperature adjustment step (S104), a blow molding step (S105), and a container removal step (S106). The first injection molding step (S101) and the first temperature adjustment step (S102) of the second embodiment are the same as those of the first embodiment.

[0122] In the second injection molding step ( S103 ) of the second embodiment, the first layer 11 of the preform 10 is accommodated in the second injection molding section 33 , and the second layer 12 is injection molded.

[0123] In the second injection molded portion 33, as shown in FIG. Figure 9As shown in (c), a mold space is formed between the inner periphery of the first layer 11 and the surface of the core mold 51 facing the inner periphery of the first layer 11, and the second resin material is filled into the mold space from the hot runner mold 52. Further, although the film portion 18 is formed at the bottom of the first layer 11, the film portion 18 is broken by the injection pressure of the second resin material to form the opening portion 16 at the bottom, and the second resin material is guided from the opening portion 16 to the inner periphery side of the first layer 11.

[0124] As described above, 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. Thus, 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 contact therebetween, and a gap between the bottom of the first layer 11 and the cavity mold 50 can be suppressed.

[0125] Further, a resin accumulation space is formed between the opening portion 16 of the first layer 11 and the recessed portion 51a of the core mold 51. The second resin material that has passed through the opening portion 16 is stirred in the resin accumulation space after hitting the recessed portion 51a of the core mold 51, and then flows 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 in the resin accumulation space, the fragments of the film portion 18 of the first layer 11 are mixed with the high-temperature second resin material and dissolved. Thus, the fragments of the film portion 18 can be made to dissipate to an extent that cannot be visually confirmed.

[0126] Further, the caliber d2 of the tip end of the hot runner mold 52 is narrowed to be smaller than the diameter dl of the opening portion 16 of the first layer 11. By increasing the flow rate of the second resin material that hits the recessed portion 51a through the tip end of the hot runner mold 52, sufficient stirring of the second resin material is generated in the resin accumulation space, and the fragments of the film portion 18 can be more easily made to dissipate. Also, the film portion 18 can be more easily broken.

[0127] Further, a part of the second resin material is guided to the outside of the first layer 11 after hitting the recessed portion 51a through the opening portion 16, and circulates in the vicinity of the opening portion 16. By such a flow, the second resin material is also stirred, and the dissipation of the fragments of the film portion 18 is promoted.

[0128] Here, the temperature of the second resin material filled in the second injection-molded portion 33 is set to a temperature lower than the melting point of the first resin material. Further, the surface temperature of the first layer 11 at the time of filling the second resin material in the second injection-molded portion 33 is cooled to a temperature below the melting point of the second resin material.

[0129] In the second injection molded portion 33, the cavity mold 50 faces the outer periphery of the first layer 11, and the shape of the first layer 11 is maintained from the outer periphery by the cavity mold 50. Therefore, even if the second resin material contacts the first layer 11, thermal deformation of the first layer 11 can be suppressed.

[0130] Furthermore, in the second injection molded portion 33, the second protrusions 54 penetrate and block the recesses 11a of the first layer 11, thereby preventing the recesses 17 of the preform 10 from being blocked by the second resin material. Furthermore, since the tips of the second protrusions 54 in the second injection molded portion 33 protrude toward the inner circumference of the first layer, the recesses 17 of the preform 10 formed by the second protrusions 54 have a shape that penetrates the first layer 11 and exposes the surface of the second layer 12 within the recesses 17.

[0131] As described above, the preform 10 in which the second layer 12 is laminated on the inner peripheral side of the first layer 11 is manufactured through the first injection molding step and the second injection molding step.

[0132] Thereafter, when the second injection molding section 33 is opened, 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 regulating section 34 while retaining the heat from the injection molding.

[0133] In addition, the second temperature adjustment step ( S104 ), the blow molding step ( S105 ), and the container removal step ( S106 ) of the second embodiment are the same as those of the first embodiment.

[0134] Hereinafter, effects of the blow molding apparatus and the blow molding method according to the second embodiment will be described.

[0135] In the second embodiment, in the second injection molding section 33, the depth of the mold space of the cavity mold 50 that accommodates the first layer 11 is made shorter than the axial length of the first layer 11. Consequently, the bottom of the first layer 11 is pressed against the bottom surface of the cavity mold 50, thereby suppressing the formation of a gap between the bottom of the first layer 11 and the cavity mold 50. Therefore, according to this embodiment, the second resin material is less likely to flow between the first layer 11 and the cavity mold 50, and molding defects such as the second resin material covering the outer periphery of the first layer 11 can be suppressed.

[0136] Furthermore, in the second embodiment, by providing the recessed portion 51a at the tip of the core mold 51, the fragments of the film portion 18 are stirred and dissolved with the hot second resin material during injection molding, thereby facilitating the dissolution of the fragments of the film portion 18. This reduces the possibility of the fragments of the film portion 18 remaining in the inner layer of the preform 10 or the peelable container 20, thereby reducing the possibility of the aesthetics being impaired due to the fragments remaining in the inner layer.

[0137] The present invention is not limited to the above-described embodiment, and various improvements and design changes are possible without departing from the spirit of the present invention.

[0138] In the above embodiment, an example in which one recess 17 is provided in the bottom 15 of the preform 10 has been described. However, for example, a plurality of recesses 17 may be provided. Figure 6 (b) shows an example in which two first protrusions 44 are provided in the second cavity mold 40B of the first injection molded part 31. Figure 6 In the example (b), the two first protrusions 44 are arranged at a point-symmetrical position with an interval of 180° about the central axis. Alternatively, the number of first protrusions 44 may be three or more. In this case, the first protrusions 44 are preferably arranged in a point-symmetrical positional relationship about the central axis.

[0139] According to the above structure, the circumferential unevenness in the flow of the resin during injection molding is further reduced. In addition, in the case of the above structure, the second protrusion 54 needs to be arranged at the same position as the first protrusion 44 in the second injection molded part 33.

[0140] The present invention is intended to be understood as being illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the foregoing description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0141] Description of Reference Numerals

[0142] 10…preform, 11…first layer, 11a…recess, 12…second layer, 16…opening, 17…recess, 18…film portion, 19, 26…locking portion, 20…peeling container, 24…air inlet hole, 30…blow molding device, 31…first injection molding portion, 33…second injection molding portion, 35…blow molding portion, 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 peelable container, comprising: A first injection molding step of injection molding a first layer of a bottomed cylindrical preform using a first resin material; a second injection molding step of injecting a second resin material different from the first resin material to laminate a second layer on the inner peripheral side of the first layer; and A blow molding step of blow molding the preform obtained in the second injection molding step while retaining the heat during injection molding to produce a peelable container. In the first injection molding step, a thin film portion is formed on a portion of the first layer, which is recessed toward the second layer relative to the outer surface of the first layer and has a thin wall thickness. In the second injection molding step, the film portion is ruptured to guide the second resin material from the opening formed in the first layer toward the inner peripheral side of the first layer, and a locking portion bulging from the opening is formed integrally with the second layer on the outer peripheral side of the first layer.

2. The method for manufacturing a peelable container according to claim 1, wherein: In the second injection molding step, 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, and the second resin material is 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 by the first injection molding step.

3. The method for manufacturing a peelable container according to claim 2, wherein: The second mold has a recessed portion formed at a portion facing an injection port for the second resin material.

4. The method for manufacturing a peelable container according to claim 3, wherein: In the second injection molding step, a size of an injection port for the second resin material is smaller than a size of an opening of the first layer formed by rupturing the thin film portion.

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

6. A device for manufacturing a peelable container, comprising: a first injection molding section for injection molding a first layer of a bottomed cylindrical preform using a first resin material; a second injection molding portion for injecting a second resin material different from the first resin material to laminate a second layer on the inner peripheral side of the first layer; and The blow molding section blows the preform obtained by the second injection molding section while it is still hot during injection molding to produce a peelable container. The first injection molded portion forms a thin film portion on a portion of the first layer that is recessed toward the second layer relative to the outer surface of the first layer and has a thin wall thickness. The second injection molded portion guides the second resin material from the opening formed in the first layer toward the inner circumference of the first layer by rupturing the film portion, and forms a locking portion bulging from the opening on the outer circumference of the first layer integrally with the second layer.

7. The manufacturing apparatus for a peelable container according to claim 6, wherein: The second injection molding part includes a first mold for accommodating the first layer in a mold space and a second mold for inserting into the interior of the first layer, and injecting 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 by the first injection molded portion.

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