Container manufacturing method, mold, and container

Abstract

A frame mold having an upper mold and a lower mold provided with a mold core (20) is used to mount a cylindrical trunk film (10) made of a laminate of plastic films in the mold core (20). A molten resin material is injected into the frame mold by an insert injection molding means to form a bottom member at the upper end of the trunk film (10), and form a frame member at the lower end of the trunk film (10). A concave portion (24) extending in the up-down direction is formed at least in the upper and lower ends of a mounting surface of the trunk film (10) in the mold core (20), and a convex portion (25) is formed at a position corresponding to the concave portion (24) in the frame mold. The bottom member and the frame member are formed in a state in which the trunk film (10) is sandwiched between the concave portion (24) and the convex portion (25).

Description

Container manufacturing method, mold and container

[0001] The present invention relates to a method for manufacturing a container, a mold, and a container. This application claims priority based on Japanese Patent Application No. 2023-108395, filed on June 30, 2023, the contents of which are incorporated herein by reference.

[0002] BACKGROUND ART Conventionally, cylindrical plastic containers made of a laminate of thin plastic films have been used as containers for storing contents for which shelf life is important, such as powdered infant formula, powdered coffee, coffee beans, and powdered supplements. These containers are easily disposable and can be reduced in volume after use.

[0003] For such plastic containers, a method is known in which a body film is inserted into an injection molding mold when molding the plastic container using a film insert method (see, for example, Patent Document 1). That is, the plastic container has a cylindrical, bottomed body formed from a plastic film and molded portions joined to one end and the other end of the body by insert injection molding. Patent Document 1 describes a method in which a laminated tubular member is pushed into the tip of a mold core, and the laminated tubular member is guided toward the base end of the mold core while gas is ejected between the mold core and the laminated tubular member, and the laminated tubular member is attached to the outer surface of the mold core.

[0004] Japanese Patent Application Publication No. 2011-189682

[0005] However, conventional plastic containers have the following problems: In conventional plastic container manufacturing methods such as those described in Patent Document 1, the circumferential length of the laminated tubular member (body film) made of a plastic laminate film that is attached (inserted) to the mold core is the same as the circumferential length of the mold core, which can make it difficult to attach the laminated tubular member to the mold core.

[0006] Therefore, if the circumference of the body film is increased (lengthened) to make it easier to attach the body film to the mold, when the mold is closed, the excess circumference of the body film that adheres to the mold core will be pushed into the gap between the molds, and the excess part of the body film will be pinched between the molds, causing wrinkles, which is a quality issue and leaves room for improvement.

[0007] The present invention was made in consideration of these circumstances, and its purpose is to provide a method for manufacturing a container, a mold, and a container that allows the body film to be easily attached to the mold core, and prevents the film from getting pinched when the mold is closed, thereby suppressing a decrease in appearance quality.

[0008] Aspect 1 of the container manufacturing method of the present invention is a container manufacturing method that uses a frame mold having an upper mold and a lower mold equipped with a mold core, attaches a tubular body film to the mold core, and injects molten resin material into the frame mold by insert injection molding means to form an upper molded portion at the upper end of the body film and a lower molded portion at the lower end of the body film, in which a recess extending in the vertical direction is formed at least at the upper and lower ends of the attachment surface of the body film on the mold core, and a convex portion is formed at a position on the frame mold corresponding to the concave portion, and the upper molded portion and the lower molded portion are formed with the body film sandwiched between the concave portion and the convex portion.

[0009] According to the first aspect of the container manufacturing method of the present invention, the circumferential length of the body film is greater than the circumferential length of the mold core excluding the recessed portion, which makes it easy to attach the body film to the mold core. Furthermore, when the mold is closed, the recessed portion of the mold core and the protruding portion on the frame mold engage with each other via the body film, so that the body film adheres closely to the recessed portion, and the entire body film adheres closely to the mold core without any excess body film in the circumferential direction. This prevents the body film from being pinched when the mold is closed, which allows high-quality upper and lower molded portions to be formed at the top and bottom ends of the body film, thereby preventing a decrease in the appearance quality of the container.

[0010] In a second aspect of the present invention, in the container manufacturing method of the first aspect, the recess is provided over the entire length of the mold core in the vertical direction.

[0011] In this case, the body film of the formed container can be easily removed from the mold core in the vertical direction, which allows for a simple configuration in which the body film is removed from the mold core in one direction, thereby simplifying the mold and reducing manufacturing costs.

[0012] Aspect 3 of the present invention is the method for manufacturing a container according to Aspect 1 or Aspect 2, wherein the mold surface on which the convex portion is formed moves in a direction perpendicular to the mounting surface.

[0013] In this case, the convex portion of the frame mold can be abutted against the concave portion extending in the vertical direction of the mold core from a direction perpendicular to the concave portion, so that the body film can be securely attached to the concave portion when the mold is closed.

[0014] A fourth aspect of the present invention is the method for manufacturing a container according to any one of the first to third aspects, wherein the mold core has a rectangular cross section.

[0015] In this case, the mounting surface of the rectangular mold core for the body film is flat, and recesses can be formed on this flat mounting surface, so that the protrusions of the frame mold can be easily and reliably engaged with the recesses when the mold is closed.

[0016] A fifth aspect of the mold according to the present invention is a method for manufacturing a container according to any one of aspects 1 to 4, in which the recesses are formed in two side surfaces located opposite each other among the four mounting surfaces.

[0017] In this case, with a simple structure in which the convex portions of the frame mold are engaged with the concave portions of the two side portions located on opposite sides of the mold core from both sides, the body film can be attached uniformly around the circumferential direction of the mold core, and high-quality containers with excellent appearance can be produced.

[0018] A sixth aspect of the present invention is the method for manufacturing a container according to any one of the first to fourth aspects, wherein the recesses are formed on each of the four mounting surfaces.

[0019] In this case, the convex portions of the frame mold engage with the concave portions of all four mounting surfaces, so the body film can be attached uniformly around the circumferential direction to the mold core, allowing for the production of high-quality containers with excellent appearance.

[0020] A seventh aspect of the present invention is a method for manufacturing a container according to any one of the first to sixth aspects, wherein the upper molding portion is formed with a bottom film placed on the top surface of the mold core.

[0021] In this case, the upper mold can be closed to attach the bottom film to the top surface of the mold core, thereby forming the upper forming portion.

[0022] In an eighth aspect of the present invention, in the method for manufacturing a container according to any one of the first to seventh aspects, the connection portion connecting the body film in the circumferential direction and the recessed portion are arranged at positions offset from each other in the circumferential direction.

[0023] In this case, the connection portion of the body film and the recess do not overlap, so the convex portion can be engaged with the body film sandwiched in the recess, and the body film can be attached to the mold core over the entire circumferential direction.

[0024] A ninth aspect of the mold according to the present invention comprises a frame mold having an upper mold and a lower mold, the lower mold comprising a mold core onto which a tubular body film is attached, the frame mold comprising a resin injection section which injects molten resin material by insert injection molding means to form an upper molding section at the upper end of the body film and a lower molding section at the lower end of the body film, the mold core having a recess extending in the vertical direction at least at the upper and lower ends of the attachment surface of the body film, and the frame mold having a protrusion at a position corresponding to the recess, so that the upper molding section and the lower molding section can be formed with the body film sandwiched between the recess and the protrusion.

[0025] According to the ninth aspect of the mold of the present invention, when inserting the body film into the mold core, the body film is formed with a circumferential length that does not fit into the mold core along the recess. In other words, the circumferential length of the body film is greater than the circumferential length of the mold core excluding the recess, making it easy to insert the film into the mold core. Furthermore, when closing the mold, the body film is sandwiched between the protrusions on the frame side of the recess in the mold core, thereby closely adhering the body film to the recess, eliminating excess body film in the circumferential direction and ensuring that the entire body film is closely adhered to the mold core. This prevents the body film from being pinched during mold closing as in the past, allowing for high-quality upper and lower molded portions to be formed at the upper and lower ends of the body film, thereby minimizing deterioration in the appearance quality of the container. A container that achieves the above-mentioned effects can be provided.

[0026] A tenth aspect of the container according to the present invention is produced by the method for producing a container according to any one of the first to eighth aspects.

[0027] According to the tenth aspect of the method for manufacturing a container according to the present invention, a container that can achieve the above-mentioned effects can be provided.

[0028] An eleventh embodiment of the container according to the present invention is produced using the mold of the ninth embodiment.

[0029] According to the eleventh aspect of the method for manufacturing a container of the present invention, a container that can achieve the above-mentioned effects can be provided.

[0030] The container manufacturing method, mold, and container of the present invention allow for easy film insertion into the mold core, and prevent the film from being pinched when the mold is closed, thereby minimizing deterioration in appearance quality.

[0031] 1 is a perspective view showing an example of a container body of a container according to an embodiment of the present invention. FIG. 1 is a perspective view of the container body shown in FIG. 1, seen from the bottom side. FIG. 2 is a view taken along the line III-III in FIG. 1, showing a side view of the container body. FIG. 3 is a view taken along the line IV-IV in FIG. 1, showing a side view of the container body. FIG. 1 is a plan view of the container body shown in FIG. 1, seen from the upper end. FIG. 2 is a side view of a mold for manufacturing the container body, showing a mold closed state. FIG. 3 is a plan view showing a slide mold opened state. FIG. 4 is a plan view showing a state in which only the slide insert portion of the slide mold is closed. FIG. 4 is a plan view showing a state in which the slide insert portion and the slide mold closing portion of the slide mold are closed. FIG. 5 is a side view showing a process of attaching a body film to the mold shown in FIG. 6. FIG. 6 is a side view showing a process of attaching a body film to the mold shown in FIG. 6. FIG. 7 is a side view of the mold shown in FIG. 6, showing a mold opened state.

[0032] Hereinafter, embodiments of a method for manufacturing a container, a mold, and a container according to the present invention will be described with reference to the drawings.

[0033] The method for manufacturing the container 1 of this embodiment shown in Figures 1 to 5 uses a frame mold 2A having an upper mold 21 and a lower mold 22 equipped with a mold core 20, as shown in Figures 6 to 11, in which a tubular body film 10 made of a laminate of plastic films is attached to the mold core 20, and molten resin material is injected into the frame mold 2A (upper mold 21 and lower mold 22) by insert injection molding means to form a bottom member 13 (upper molded portion) at the upper end (upper opening edge 10a) of the body film 10 and a frame member 12 (lower molded portion) at the lower end (lower opening edge 10b).

[0034] <Container Structure> Here, the container 1 to be manufactured will be described with reference to Figures 1 to 5. The container 1 comprises a container body 1A and a lid member (not shown) fitted to the upper open end 10a of the container body 1A. The body portion of the container 1 is formed from a body film 10 made of a laminated film made of a plastic film or the like.

[0035] Container 1 is a container for storing powders such as powdered infant formula, powdered coffee, and powdered supplements, or granular materials such as rice and coffee beans. Container 1 may also be a container for storing paste-like contents such as miso paste or jam, or liquids. Furthermore, the contents of container 1 are not limited to food, and may also be everyday items such as detergents and caulking materials.

[0036] The container 1 is substantially rectangular parallelepiped (quadrature) in shape. However, the shape of the container 1 is not limited to a cuboid, and may be, for example, cylindrical or a polygonal prism other than a quadrangular prism.

[0037] In this embodiment, the mold core 20 of the mold 2 is formed into a cylindrical shape with a rectangular cross section, and the mold axis passing through the center of the cross section is called the mold axis O, the direction along the mold axis O is called the axial direction, and along the mold axis O, the lower mold 22 side is called the downward direction, and the upper mold 21 side is called the upward direction. In addition, in a plan view seen from the axial direction, the direction perpendicular to the mold axis O is called the radial direction, and the direction going around the mold axis O is called the circumferential direction.

[0038] 1 and 2 , the container body 1A includes a body member 11, a frame member 12 provided at the upper end of the body member 11, and a bottom member 13 provided at the lower end of the body member 11. The container body 1A has a lower opening end 10b that is open at the top end, and an upper opening end 10a that is closed at the bottom end by the bottom member 13. The upper end (lower opening end 10b) of the body member 11 corresponds to the lower end of the body film 10 attached to the mold core 20, closer to the lower mold 22, and the lower end (upper opening end 10a) of the body member 11 corresponds to the upper end of the body film 10 attached to the mold core 20, closer to the upper mold 21.

[0039] The body member 11 is a cylindrical body having an upper opening end 10 a and a lower opening end 10 b. As will be described later in the manufacturing method of the container body 1A, the body member 11 is formed into a cylindrical shape by, for example, enveloping the rectangular body film 10 by overlapping the inner surface of one circumferential end with the outer surface of the other circumferential end.

[0040] Furthermore, body member 11 can stand on its own in a cylindrical state when upper open end 10 a or lower open end 10 b is placed on a flat surface. Here, "stand-alone" means that body member 11 is formed into a cylindrical or bag-like shape using body film 10, and has sufficient rigidity to maintain a self-standing state without buckling or deforming under its own weight.

[0041] The body film 10 is composed of a laminate having, for example, a heat-sealed layer that forms the outer peripheral surface of the body member 11, an intermediate layer that imparts predetermined strength and gas barrier properties to the body film 10, and a heat-sealed layer that forms the inner peripheral surface of the body member 11. The layers of this laminate are bonded together by an adhesive layer. This laminate structure of the body film 10 is one example and can be modified as appropriate.

[0042] The heat-sealable layer is a layer that can be heat-sealed. This allows the heat-sealable layer to adhere to the frame member 12 and the bottom member 13. The heat-sealable layer is a plastic film formed from a resin material such as low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (L-LDPE), or polypropylene (PP). The heat-sealable layer is preferably an unstretched film made from these resin materials. Alternatively, the heat-sealable layer may be a multilayer film co-extruded with a combination of these resin materials or other resin materials. The thickness of the heat-sealable layer is preferably in the range of 10 to 200 μm, more preferably 20 to 150 μm.

[0043] The intermediate layer is provided between the heat-sealable layers and preferably has excellent printability as well as puncture strength, tensile strength, and impact resistance. The intermediate layer is a plastic film formed from a resin material such as polyester, such as medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), or polybutylene terephthalate (PBT), polypropylene (PP), polyamide (PA), or ethylene-vinyl alcohol copolymer (EVOH). The intermediate layer may be either a stretched or unstretched film made from the above materials. The thickness of the intermediate layer is preferably in the range of 4 to 50 μm, more preferably 7 to 30 μm.

[0044] The intermediate layer may be, for example, a metal foil made of aluminum, magnesium, iron, copper, or the like; a vapor-deposited film on which a metal such as aluminum or magnesium or an oxide such as silicon oxide is vapor-deposited; or a coated film coated with a barrier coating agent such as polyvinylidene chloride. By providing any of these as the intermediate layer, gas barrier properties can be imparted to the body film 10. The intermediate layer may also be a multilayer plastic film obtained by co-extrusion of a combination of multiple resin materials. The intermediate layer may be composed of a single layer, or two or more layers.

[0045] The body member 11 is not limited to a single body film 10 formed into a cylindrical shape by enveloping or the like. For example, the body member 11 may be formed into a cylindrical shape by bending a back-bonded portion formed by heat-sealing the back surfaces (inner surfaces) of the left and right ends of a single rectangular body film toward the body member, or by heat-sealing the opposing edges of two rectangular body films, or by cutting a tube made of a blown-film-molded single-layer or multi-layer plastic film to a desired length.

[0046] The body member 11 has a rectangular cross section. A pair of side surfaces of the body member 11 extending in the long side direction X2 along the long side of the rectangle are provided with a plurality of grooves 14 spaced apart in the circumferential direction (long side direction X2), the grooves 14 extending the entire length in the vertical direction (axial direction). In this embodiment, four grooves 14 are formed on each side surface. In the formed container body 1A, by providing the grooves 14 extending the entire length in the vertical direction in the body member 11, it is expected that the compressive strength of the body member 11 in the direction along the mold axis O will be improved.

[0047] Note that the above-described recessed grooves 14 are not formed in the cylindrical body film 10 before it is manufactured into the container 1 using the mold 2. The circumferential length of the body film 10 is set to be, for example, about 1.2 mm larger than the circumferential length not including the length of the concave inner surface of a recess 24 (described later) of the mold core 20 (in other words, the circumferential length of the mold core 20 assuming that the recess 24 is not formed in the mold core 20). The circumferential length of the body film 10 is set to be approximately the same dimension as the overall circumferential length of the mold core 20, including the length of the concave inner surface of the recess 24. In other words, the circumferential length of the body film 10 is approximately equal to the length at which the body film 10 adheres tightly to the mold core 20 with no gaps when the mold is closed and the body film 10 is in close contact with the recess 24 of the mold core 20. If the circumference of the body film 10 is too long compared to the overall circumference of the mold core 20, the excess portion of the body film 10 that has become loose and non-adhered may gather together in the area between the split slide dies 23A and 23B described below, i.e., in the center of the short side direction X1 of the mold core 20, and may be cut off by the split slide dies 23A and 23B, causing a hole to form.

[0048] The frame member 12 is provided so as to be connected to the outer peripheral surface of the lower opening end 10b of the body member 11. The frame member 12 reinforces the edge of the lower opening end 10b so that the lower opening end 10b maintains a predetermined opening shape (rectangle, polygon, circle, etc.). The frame member 12 is formed in a first molding space S1 of the mold 2, which will be described later.

[0049] As shown in Figures 1, 3, and 4, the frame member 12 is composed of a reinforcing portion 121, a flange portion 122, and a fitting portion 123. The reinforcing portion 121 is arranged to cover the lower open end 10b of the body member 11 from the outside and reinforces the lower open end 10b. The fitting portion 123 is fitted into a fitting portion (not shown) formed on the lid member when attaching the lid member (not shown) to the container body 1A. The flange portion 122 is arranged between the reinforcing portion 121 and the fitting portion 123 and holds the lid member fitted into the fitting portion 123. The frame member 12 is made of a material such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, or polypropylene.

[0050] 2 and 5, the bottom member 13 is joined to the inner peripheral surface of the lower end of the body member 11 and is formed to close the upper open end 10a of the body member 11. The bottom member 13 closes the lower open end 10b of the body member 11 in an airtight or liquid-tight manner depending on the type and properties of the contents of the container 1. The material of the bottom member 13 is, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, or the like.

[0051] <Mold> Next, the mold 2 will be described with reference to Figures 6 to 11. As shown in Figure 6, the mold 2 has an upper mold 21 and a lower mold 22 that partially includes a mold core 20. Here, the upper mold 21 and the lower mold 22 correspond to a frame mold 2A. The lower mold 22 includes a slide mold 23. In the mold 2, with the body film 10 attached to the mold core 20, the upper mold 21 and the lower mold 22 that includes the slide mold 23 are closed together, and resin is then filled into desired locations, thereby integrally forming the frame member 12 and bottom member 13 shown in Figures 1 and 2 on the body film 10.

[0052] The slide die 23 provided on the lower die 22 is provided so as to be able to advance and retreat by being guided by the upper surface 22a of the lower die 22. The upper surface 22a of the lower die 22 is in contact with the lower surface of the slide die 23 at least around the periphery of the mold core 20.

[0053] The mold core 20 is located at the center of the upper surface 22a of the lower mold 22 in a plan view. "Plan view" refers to a view from the mold axis O. The mold core 20 has a substantially rectangular cross section (a cross section perpendicular to the mold axis O) from the base end to the tip end, and the outer periphery of the mold core 20 is the same throughout the axial direction. The cylindrically formed body film 10 is attached to the peripheral wall 20a of the mold core 20 using a transfer jig (not shown). A method for transferring the body film 10 to the mold core 20 using the transfer jig will be described later.

[0054] The mold core 20 has a cylindrical peripheral wall 20a (side surfaces 20aA, 20aB, 20aC, and 20aD) with four sides, and a top surface 20b covering the tip of the peripheral wall 20a. A pair of first side surfaces 20aA and 20aB, which form the long sides of the peripheral wall 20a of the mold core 20 and are located opposite each other, each have a plurality of recesses 24 formed circumferentially, extending over the entire vertical (axial) direction. Here, four recesses 24 are formed on each of the first side surfaces 20aA and 20aB. Furthermore, a pair of second side surfaces 20aC and 20aD, which form the short sides of the peripheral wall 20a and are located opposite each other, are formed as flat surfaces without any irregularities. The recesses 24 are provided to form the recessed grooves 14 (see FIGS. 1 and 2 ) formed in the body film 10 described above.

[0055] The total circumferential length, including the length of the concave inner surfaces of the recesses 24 in the mold core 20, is set to approximately the same dimension as the circumferential length of the body film 10. In other words, the total length in the circumferential direction of the lengths of the concave inner surfaces of all (eight in this case) recesses 24 formed in the mold core 20 and the lengths of the parts other than the recesses 24 is set to the same dimension as the circumferential length including the above-mentioned excess length (for example, about 1.2 mm) of the body film 10. This ensures that the body film 10 is attached in close contact with the mold core 20 when the body film 10 is closed.

[0056] The slide die 23 has split slide dies 23A and 23B that are split in two in the short side direction X1 of the mold core 20 across the mold axis O of the mold core 20. That is, the split slide dies 23A and 23B are provided so as to be movable forward and backward in the short side direction X1. When the mold is closed, the slide die 23 covers the entire peripheral wall portion 20a of the mold core 20 from the outside.

[0057] As shown in FIGS. 7 to 9, each of the divided slide molds 23 A and 23 B has a slide insert portion 231 and a slide mold closing portion 232 .

[0058] The slide insert portion 231 is disposed at the center of the slide mold closing portion 232 in the long side direction X2 of the mold core 20, and is provided so as to be movable relative to the slide mold closing portion 232 in the short side direction X1. The slide insert portion 231 has a first mold closing surface 231a that faces only the first side surfaces 20aA, 20aB of the mold core 20. A plurality of protrusions 25 (the same number as the recesses 24) are formed on the first mold closing surface 231a at intervals in the long side direction X2 and are provided so as to be engageable with a plurality of recesses 24 formed on the first side surfaces 20aA, 20aB. The protrusion height of the protrusions 25, similar to the recess depth of the recesses 24, is, for example, preferably 0.5 to 2.5 mm, more preferably 0.7 to 1.5 mm, and even more preferably 1.0 to 1.2 mm. During mold closing, the slide insert portion 231 abuts the first mold closing surface 231 a against the first side surfaces 20 aA, 20 aB of the mold core 20 before the slide mold closing portion 232 does so.

[0059] The sliding mold closing portion 232 is movable in the short side direction X1 relative to the sliding insert portion 231. The sliding mold closing portion 232 has a second mold closing surface 232a that contacts the corner portion of the mold core 20 and the second side surfaces 20aC and 20aD. During mold closing, after the mold is closed by the sliding insert portion 231, the sliding mold closing portion 232 a abuts the second mold closing surface 232a from the corner portion of the mold core 20 against the second side surfaces 20aC and 20aD to close the mold.

[0060] As shown in Figures 6 and 7, the inner surfaces of the slide insert portions 231 of the split slide molds 23A, 23B are formed with spaces corresponding to the shape of the frame member 12 (see Figure 1) to be molded around the lower opening edge 10b of the body film 10. When the slide molds 23 are in the mold-closed position relative to the lower mold 22 (mold core 20), a first molding space S1 for forming the frame member 12 is formed between the base end of the mold core 20 and the upper surface 22a of the lower mold 22. This first molding space S1 is connected to a resin injection section (not shown) provided in the slide mold 23 for filling with molten resin. This allows molten resin to flow into the first molding space S1. When the molten resin is filled into the first molding space S1 and hardens, the frame member 12 is integrally bonded to the lower opening edge 10b of the body film 10.

[0061] As shown in Figures 6 and 10A to 10C, the outer periphery of each split slide mold 23A, 23B is formed with a tapered surface 23b that gradually reduces in diameter from bottom to top. Furthermore, the upper surfaces 23c of each split slide mold 23A, 23B are formed with positioning holes 233 that are aligned with the tapered surface 23b. Positioning pins 213 provided on the upper mold 21 can be inserted into the positioning holes 233. When the upper mold 21 approaches the lower mold 22 in the axial direction and the positioning pins 213 of the upper mold 21 are inserted into the positioning holes 233, the pair of split slide molds 23A, 23B move in a direction approaching each other (the mold closing direction). In other words, the slide mold 23 is closed simultaneously with the movement of the upper mold 21.

[0062] The upper mold 21 is provided so as to be movable axially back and forth relative to the mold core 20 of the lower mold 22. The upper mold 21 has a base portion 211 and an outer peripheral frame 212 that protrudes downward from the base portion 211. The outer peripheral frame 212 is an outer peripheral side wall formed around the entire circumferential direction. A tapered surface 21b that gradually increases in diameter from top to bottom is formed on the inner peripheral portion of the outer peripheral frame 212. A bottom surface (lower surface) 212a is formed inside the outer peripheral frame 212.

[0063] Furthermore, a positioning pin 213 is formed on the lower surface of the base portion 211, and is aligned with the tapered surface 21b. The positioning pin 213 is provided so as to be insertable into a positioning hole 233 formed in the slide mold 23. When the upper mold 21 approaches the lower mold 22 in the axial direction and the positioning pin 213 of the upper mold 21 is inserted into the positioning hole 233, the pair of split slide molds 23A, 23B move in a direction approaching each other (in the mold closing direction).

[0064] As shown in Figure 6, when the upper mold 21 is in the mold closed position relative to the mold core 20, a second molding space S2 corresponding to the shape of the bottom member 13 (see Figure 2) to be molded on the upper open end 10a of the body film 10 is formed between the top surface 20b of the mold core 20 and the lower surface 212a of the outer peripheral frame 212 of the upper mold 21. This second molding space S2 communicates with a resin injection section (not shown) provided in the upper mold 21 for filling with molten resin. This allows molten resin to flow into the second molding space S2. When the molten resin is filled into the second molding space S2 and hardens, the bottom member 13 is integrally bonded to the upper open end 10a of the body film 10.

[0065] <Container Manufacturing Method> Next, a method for manufacturing the container 1 using the above-described mold 2 will be specifically described with reference to Figures 1 to 11. First, a laminate film is used to form a cylindrical body film 10. For example, the body film 10 is formed by overlapping the ends of a rectangular laminate film and sealing them together to form an envelope.

[0066] 10A to 10C are side views showing the process of attaching the body film 10 to the mold 2. Fig. 10A shows the mold open state in which the upper mold 21 and the lower mold 22 are separated. Fig. 10B shows the state in which the body film 10 is waiting above the mold core 20, held by a delivery jig (not shown). Fig. 10C shows the state in which the body film 10 has been attached to the mold core 20.

[0067] Next, as shown in Figure 10A, the mold 2 is placed in an open state. That is, in the open state, the upper mold 21 and slide mold 23 are separated from the lower mold 22 having the mold core 20. Then, as shown in Figure 10B, with the mold 2 in the open state, a tubular body film 10 held by a transfer jig (not shown) is placed on standby above the mold core 20. Thereafter, as shown in Figure 10C, the waiting body film 10 is attached so as to cover the mold core 20. In this case, if the body film 10 is pre-formed into a rectangular cylindrical shape, attachment to the mold core 20 can be carried out smoothly, but pre-forming the body film 10 into a rectangular cylindrical shape is not essential. As long as the body film 10 is at least formed into a cylindrical shape, attachment to the mold core 20 can be carried out smoothly.

[0068] At this time, the body film 10 does not have the recessed grooves 14 formed therein, and therefore is attached to the mold core 20 with a slight gap therebetween. In other words, the circumferential length of the body film 10 is set to be slightly larger than the circumferential length of only the outer periphery, excluding the inner periphery of the recessed portion 24 of the mold core 20, and therefore the body film 10 can be easily attached to the mold core 20.

[0069] Next, as shown in Figures 7, 8, and 11, the upper mold 21 is lowered and the positioning pins 213 of the upper mold 21 are inserted into the positioning holes 233 of the slide mold 23, thereby moving the pair of split slide molds 23A, 23B in the short side direction X1 toward the mold core 20. Specifically, as shown in Figure 8, the slide insert 231 is first moved toward the mold core 20, and the first mold closing surface 231a is brought into contact with the first side surfaces 20aA, 20aB of the mold core 20 with the body film 10 sandwiched between them. At this time, the convex portions 25 of the first mold closing surface 231a engage with the concave portions 24 of the first side surfaces 20aA, 20aB. As a result, grooves 14 are formed in the body film 10 located on the first side surfaces 20aA, 20aB.

[0070] 9, the slide mold closing portion 232 is moved toward the mold core 20, and the second mold closing surface 232a is brought into contact with the second side surfaces 20aC, 20aD of the mold core 20 with the body film 10 sandwiched between them. At the same time, the upper mold 21 also moves downward, as shown in FIG. 6, and mold closing is completed.

[0071] After the mold is closed, molding spaces S1 and S2 are formed between the body film 10 and the mold 2. Specifically, a first molding space S1 is formed between the base end of the mold core 20 and the upper surface 22a of the lower mold 22. A second molding space S2 is formed between the lower surface 212a of the outer frame 212 of the upper mold 21 and the top surface 20b of the mold core 20. In the next step, a synthetic resin material is injected in a molten state into the first molding space S1 and the second molding space S2 by insert injection molding means through a filling channel (not shown) provided in the mold 2. This forms the frame member 12 and the bottom member 13, which are integrally joined to the body film 10. This completes the manufacture of the container body 1A.

[0072] Next, a method for manufacturing the container 1 configured as above, and the functions of the mold 2 and the container 1 will be described in detail.

[0073] The method for manufacturing a container 1 according to this embodiment uses a frame mold 2A having an upper mold 21 and a lower mold 22 equipped with a mold core 20, attaches a tubular body film 10 made of a laminate of plastic films to the mold core 20, and injects molten resin material into the frame mold by insert injection molding to form a bottom member 13 at the upper end of the body film 10 and a frame member 12 at the lower end. In the method for manufacturing container 1, recesses 24 extending in the vertical direction are formed on at least the upper and lower ends of the attachment surface of the body film 10 on the mold core 20, and protrusions 25 are formed in the frame mold at positions corresponding to the recesses 24, and the bottom member 13 and frame member 12 are formed with the body film 10 sandwiched between the recesses 24 and the protrusions 25.

[0074] Moreover, the mold 2 according to this embodiment includes a frame mold 2A having an upper mold 21 and a lower mold 22. The lower mold 22 includes a mold core 20 to which a tubular body film 10 made of a laminate of plastic films is attached. The frame mold 2A includes a resin injection section that injects molten resin material by insert injection molding to form a bottom member 13 at the upper end of the body film 10 and a frame member 12 at the lower end. The mold core 20 has recesses 24 extending in the vertical direction at least at the upper and lower ends of the attachment surface for the body film 10, and protrusions 25 are formed in the frame mold at positions corresponding to the recesses, so that the bottom member 13 and the frame member 12 can be formed with the body film 10 sandwiched between the recesses 24 and the protrusions 25.

[0075] According to the container manufacturing method of this embodiment, the body film 10 is attached to the mold core 20, and when mold closing is not complete, the body film 10 is formed with a circumferential length that does not adhere to the mold core 20 along the recess 24. That is, the circumferential length of the body film 10 is greater than the circumferential length of the mold core 20 excluding the recess 24, making it easy to attach the body film 10 to the mold core 20. Furthermore, when the mold 2 is closed, the recess 24 of the mold core 20 and the protrusion 25 on the frame mold side fit together via the body film 10, so that the body film 10 adheres closely to the recess 24, and no excess body film 10 remains in the circumferential direction, allowing the entire body film 10 to adhere closely to the mold core 20. This prevents wrinkles from occurring in the body film 10 due to pinching during mold closing as in the conventional method, allows the bottom member 13 and frame member 12 to be formed with high quality at the upper and lower ends of the body film 10, and prevents deterioration in the appearance quality of the container 1.

[0076] In addition, in this embodiment, the recesses 24 are provided over the entire length of the mold core 20 in the vertical direction, which makes it easier to remove the body film 10 of the formed container 1 in the vertical direction from the mold core 20. This allows for a simple configuration in which the mold core 20 is removed from the body film 10 in one direction, which simplifies the mold 2 and reduces manufacturing costs.

[0077] Furthermore, in this embodiment, the first mold closing surface 231a (mold surface) on which the convex portion 25 of the frame mold 2A is formed can be moved in a direction perpendicular to the attachment surface, thereby allowing the convex portion 25 of the frame mold to abut from a direction perpendicular to the concave portion 24 extending in the vertical direction of the mold core 20, so that the body film 10 can be securely attached to the concave portion 24 when the mold is closed.

[0078] Furthermore, in this embodiment, by using a mold core 20 having a rectangular cross section, the mounting surface of the rectangular mold core 20 onto which the body film 10 is attached becomes flat, and the recesses 24 can be formed on this flat mounting surface. Therefore, the protrusions 25 of the frame mold can be easily and reliably engaged with the recesses 24 when the mold is closed.

[0079] In this embodiment, the recesses 24 are formed on two side surfaces (first side surfaces 20aA, 20aB) that are located on opposite sides of the four attachment surfaces. Therefore, with a simple structure in which the frame-shaped protrusions 25 are engaged with the recesses 24 on the two side surfaces that are located on opposite sides of the mold core 20 from both sides thereof, the body film 10 can be attached uniformly in the circumferential direction to the mold core 20, and a high-quality container 1 with excellent appearance can be manufactured.

[0080] Furthermore, in this embodiment, the connection portions that connect the laminate in the body film 10 in the circumferential direction and the recesses 24 are positioned at positions that are offset in the circumferential direction. Therefore, the connection portions of the body film 10 do not overlap with the recesses 24, and the protrusions 25 can be engaged with the recesses 24 while the body film 10 is sandwiched between them, allowing the body film 10 to be attached to the mold core 20 over the entire circumferential direction.

[0081] Furthermore, in this embodiment, since the container 1 is manufactured by the manufacturing method described above, it is possible to provide the container 1 that can achieve the effects described above.

[0082] Furthermore, in this embodiment, since the container 1 is manufactured using the mold 2 described above, it is possible to provide the container 1 that can achieve the effects described above.

[0083] The container manufacturing method, mold, and container of this embodiment configured as described above allow the tubular body film to be easily attached to the mold core 20, and prevents the film from getting pinched when the mold is closed, thereby suppressing a decrease in appearance quality.

[0084] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and their modifications include, for example, those that can be easily imagined by a person skilled in the art, those that are substantially the same, those that are equivalent, etc.

[0085] For example, in the above embodiment, an example is shown in which the shape of the body film 10 is a tube with a substantially rectangular cross section, but the cross-sectional shape is not limited to a substantially rectangular shape and may be, for example, circular.

[0086] Furthermore, the mold 2 of this embodiment is configured such that the lower mold 22 is provided with the slide mold 23, and the divided slide molds 23A and 23B slide in the short side direction X1 relative to the lower mold 22, but is not limited to this type of mold 2. For example, a mold may be configured such that the slide mold 23 is omitted. In this case, it is sufficient that a convex portion 25 is provided on a part of the upper mold, and that the convex portion 25 is configured to approach and move away from the concave portion 24 of the mold core 20.

[0087] In this embodiment, the recesses 24 may be formed on each of the four mounting surfaces of the mold core 20. In this case, the protrusions 25 of the frame mold are engaged with the recesses 24 on all four mounting surfaces, so that the body film 10 can be attached uniformly around the circumferential direction of the mold core 20, improving the quality of the container.

[0088] Furthermore, the recess 24 may be provided on only one of the multiple mounting surfaces of the mold core 20.

[0089] In addition, in this embodiment, the recesses 24 are configured to be provided over the entire vertical direction of the mold core 20, but this is not limited to the entire configuration. In short, it is sufficient that recesses extending in the vertical direction are formed at least at the upper and lower ends of the attachment surface of the mold core 20 to which the body film 10 is attached.

[0090] Furthermore, the shape (depth, width (circumferential length)) and number of the recesses 24, and the shape (height, width (circumferential length)) and number of the protrusions 25, etc. can be set to any desired configuration.

[0091] In addition, in this embodiment, a bottom film made of a laminated film having the same configuration as the body film 10 can be placed on the top surface 20b of the mold core 20, and the upper mold 21 can be closed, and a molten resin material can be injected into the second molding space S2 by insert injection molding means to form a bottom member 13 (upper molding portion) integrated with the bottom of the body film 10.

[0092] With regard to the components of the body film 10, from the viewpoint of material recyclability, the higher the mono-material ratio (the proportion of a single material) of the body film 10, the better, with 80% or more being preferred, and 90% or more being more preferred. Specifically, polyethylene, polypropylene, a mixture of polyethylene and polypropylene, or the like can be used as the resin material constituting the body film 10. A high mono-material ratio is preferable in that it leaves less residue during material recycling, enables more efficient recycling, and reduces the environmental burden.

[0093] DESCRIPTION OF SYMBOLS 1 Container 1A Container body 2 Mold 2A Frame mold 10 Body film (mounting surface) 10a Upper opening edge 10b Lower opening edge 11 Body member 12 Frame member (lower forming portion) 13 Bottom member (upper forming portion) 14 Groove 20 Mold core 20a Peripheral wall portion 20aA, 20aB First side surface 20aC, 20aD Second side surface 20b Top surface 21 Upper mold 22 Lower mold 23 Slide mold 23A, 23B Divided slide mold 231 Slide insert portion 231a First mold closing surface (mold surface) 232 Slide mold closing portion 232a Second mold closing surface 24 Concave portion 25 Convex portion O Mold axis S1 First molding space S2 Second molding space X1 Short side direction X2 Long side direction

Claims

1. A method for manufacturing a container, using a frame mold having an upper mold and a lower mold equipped with a mold core, attaching a tubular body film to the mold core, and injecting molten resin material into the frame mold by insert injection molding means to form an upper molded portion at the upper end of the body film and a lower molded portion at the lower end of the body film, wherein a recess extending in the vertical direction is formed at least at the upper and lower ends of the attachment surface of the body film on the mold core, a protrusion is formed in the frame mold at a position corresponding to the recess, and the upper molded portion and the lower molded portion are formed with the body film sandwiched between the recess and the protrusion.

2. A method for manufacturing a container as described in claim 1, wherein the recess is provided over the entire vertical length of the mold core.

3. The method for manufacturing a container according to claim 1, wherein the mold surface on which the convex portion is formed moves in a direction perpendicular to the mounting surface.

4. A method for manufacturing a container according to claim 1, wherein the mold core has a rectangular cross section.

5. The method for manufacturing a container according to claim 4, wherein the recesses are formed in two side surfaces located opposite each other among the four mounting surfaces.

6. The method for manufacturing a container according to claim 4, wherein the recess is formed on each of the four mounting surfaces.

7. The method for manufacturing a container according to claim 1, wherein the upper molding portion is formed with a bottom film placed on the top surface of the mold core.

8. The method for manufacturing a container according to claim 1, wherein the connection portion that connects the body film in the circumferential direction and the recess are positioned at positions offset in the circumferential direction.

9. A mold comprising a frame mold having an upper mold and a lower mold, the lower mold having a mold core onto which a tubular body film is attached, the frame mold having a resin injection section for injecting molten resin material by insert injection molding means to form an upper molded portion at an upper end of the body film and a lower molded portion at a lower end of the body film, the mold core having recesses extending in the vertical direction at least at the upper and lower ends of the attachment surface for the body film, the frame mold having protrusions at positions corresponding to the recesses, and the mold is configured so that the upper molded portion and the lower molded portion can be formed with the body film sandwiched between the recesses and the protrusions.

10. A container manufactured by the method for manufacturing a container according to any one of claims 1 to 8.

11. A container manufactured using the mold of claim 9.

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