JP7664151B2 - Composite container and method for manufacturing the same - Google Patents

Description

The present invention relates to a composite container and a method for manufacturing a composite container.

In recent years, efforts have been made to reduce the amount of resin used in disposable containers in order to curb the burden on the natural environment caused by plastic waste, including microplastics. Specific efforts include reducing the amount of resin used in plastic containers and replacing plastic products with paper products. In addition, composite containers that combine plastic containers with paper components have also been proposed.

For example, Patent Document 1 proposes a composite container that combines a resin container with a paper sleeve (reinforcing member). In this composite container, the amount of resin is reduced by providing a thin-walled portion with a thickness of 0.01 mm to 0.09 mm in the body of the resin container. However, when such a thin-walled portion is provided in the body, the body is easily deformed and cannot be gripped. Therefore, in this resin container, a flange portion connected to the body, a thick-walled portion connected to the flange portion in the body, and a protrusion that protrudes radially outward from the thick-walled portion are provided, and the thin-walled portion is located on the bottom side of the thick-walled portion. Then, the body of the resin container is inserted into a cylindrical paper sleeve and the sleeve is supported by the protrusion, so that the resin container and the paper sleeve can be easily attached, and the rigidity of the resin container, which is reduced by the thin-walled portion, is reinforced by the sleeve.

JP 2021-116122 A

According to the composite container disclosed in Patent Document 1, the amount of resin in the body is reduced by obtaining rigidity with a paper sleeve. However, a thick-walled section is provided at the top of the body, and the bottom is also made thicker than the thin-walled section in order to maintain a certain level of strength. As a result, there is still a large amount of resin, and a further reduction in the amount of resin used is required.

Furthermore, with the above composite container, the resin container and the paper sleeve must be prepared separately, and then the paper sleeve must be attached to the resin container. The resin container is produced by blow molding using a preform, and the paper sleeve is produced by rolling up a piece of paperboard or the like that has been cut into a predetermined shape including a main body and a margin, and then gluing the main body and margin with an adhesive or the like. As such, the manufacturing process for the above conventional composite containers is complicated, and there is a demand for improved manufacturing efficiency.

The paper sleeve is made of laminated paper with a functional film having functions such as water resistance laminated on the surface. The composite container contains food and other moisture-containing contents. The cut surface of the paper sleeve is not covered with a functional film, so moisture may penetrate through the cut surface and cause the paper sleeve to become swollen due to moisture. In such cases, the paper sleeve may not be able to maintain the rigidity required for the paper sleeve. If the cut surface is exposed, the laminated structure may not be maintained, for example, the functional film on the surface may peel off from the edge, and the paper sleeve may not be able to maintain the rigidity and appearance required for the paper sleeve.

The objective of the present invention is to provide a composite container and a manufacturing method thereof that can significantly reduce the amount of resin and improve manufacturing efficiency by combining a resin framework with a paper tubular body, while maintaining the functionality required of the paper tubular body.

In order to solve the above problems, the composite container of the present invention has a bottom and sides, and has a storage section constructed using a resin framework and a paper tubular body, the paper tubular body being one or more paper face pieces formed into a cylindrical shape, the framework having a joint portion interposed between one end edge portion and the other end edge portion of the paper face piece and covering the entire end faces of the one end edge portion and the other end edge portion , the one end edge portion and the other end edge portion being folded to protrude from the outer surface of the tubular body and embedded within the joint portion .

In the composite container, the framework comprises a bottom framework that forms the outer edge of the bottom surface, a top framework that forms the outer edge of the top surface of the storage section, and a side framework that includes the joint and is connected to the bottom framework and the top framework, the side surface of the storage section is formed by the side framework and a side paper panel that forms a cylinder by joining the one end edge and the other end edge to the joint, the bottom surface of the storage section is formed by the bottom framework and a bottom paper panel whose outer edge is joined to the bottom framework, and it is preferable that the bottom edge of the paper tube is joined to the bottom framework and the top edge is joined to the top framework.

In order to solve the above problem, the manufacturing method of the composite container according to the present invention is a method for manufacturing the composite container, and is characterized in that a mold is used that has one mold member and the other mold member that are divided via a dividing surface, and that by combining the one mold member and the other mold member, a resin-filled portion having a shape corresponding to the framework is formed, and the paper face piece is placed between the one mold member and the other mold member so that an edge portion of the paper face piece is inserted into a joint-forming area in the resin-filled portion that has a shape corresponding to the joint, and is sandwiched between the two mold members, and resin is filled into the resin-filled portion, whereby the one edge portion and the other edge portion of the paper face piece are joined by the joint, and the composite container in which the framework and the tubular body are integrated is obtained.

In the manufacturing method of the composite container according to the present invention, it is preferable that a convex portion is provided in the joint forming region, protruding from the parting surface of the one mold member toward the other mold member, and resin is filled into the resin filling portion while the edge portion of the paper face body is pushed up toward the other mold member by the convex portion.

In the manufacturing method of the composite container according to the present invention, at the position where the edge portion is located within the joint forming region, a recess is provided near the protrusion on the parting surface of one of the mold members, and the protrusion and the recess are arranged in this order from the end face side of the edge portion, and when the resin is filled in the resin filling portion, the edge portion is preferably folded by the resin filling pressure and the recess and the protrusion.

According to the composite container of the present invention, the storage section is constructed using a resin framework and a paper tubular body, which allows for a significant reduction in the amount of resin used compared to when the entire storage section is constructed from resin. Furthermore, the framework only needs to be made thick enough to compensate for the strength deficiencies of the paper tubular body alone, so less resin is required for the framework.

Here, the paper tubular body is one or more paper face pieces made into a cylindrical shape, and a joint of the framework is interposed between one end edge and the other end edge of the paper face piece, and the entire end faces of each end edge are covered and joined by the joint. When the composite container is used as a container for storing contents containing moisture such as food or liquid, moisture may adhere to the joint of the paper face piece. In such a case, since the entire end faces of the one end edge and the other end edge are covered in the present invention, it is possible to prevent moisture, etc. from entering the joint from the end face. Therefore, even if the end face of the paper face piece is a cut surface, it is possible to suppress defects such as moisture, etc. entering from the end face to reduce rigidity, and when the paper face piece is made of laminated paper in which multiple sheets are stacked, it is possible to suppress defects such as the laminated sheets peeling off from the surface and the joint strength between the end edges being reduced. As a result, the rigidity required for the paper tubular body and the appearance of the composite container can be maintained well, and the functions required for the paper tubular body can be maintained.

Furthermore, according to the manufacturing method of the composite container of the present invention, the insert molding method can be applied. That is, by placing the paper facepiece at a predetermined position in the mold and filling the resin filling portion of the mold with resin, the edge portion of the paper facepiece is inserted into the joint forming area, and at the same time as forming the framework, one edge portion of the paper facepiece and the other edge portion are joined by the joint to obtain an integrated composite container. This eliminates the need to manufacture and assemble the resin and paper portions separately, improving manufacturing efficiency.

As described above, the composite container and the manufacturing method for the composite container according to the present invention can reduce the amount of resin and improve manufacturing efficiency by combining a resin framework with a paper tubular body, while maintaining the functionality required of the paper tubular body.

1A and 1B are diagrams for explaining a composite container according to an embodiment of the present invention, in which FIG. 1A is a front view (partial cross-sectional view) of the composite container, and FIG. 1B is a bottom view of the composite container. 2A and 2B are diagrams showing the composite container shown in FIG. 1, in which FIG. 2A is a top view and FIG. 2B is a side view (partially cross-sectional view). 2A and 2B are diagrams showing the paper face pieces that make up the cylindrical body of the composite container shown in FIG. 1, where (a) shows the side paper face piece that makes up the side of the storage section, and (b) shows the bottom paper face piece that makes up the bottom of the storage section. With regard to the composite container shown in FIG. 1, (a) is a cross-sectional view taken along the line A-A in FIG. 1(a), (b) is a schematic diagram showing a side cross-sectional structure of a mold used to mold the relevant portion, and (c) is a schematic diagram for explaining a molding method. Regarding a comparative example for comparison with the composite container shown in FIG. 1, (a) is a diagram corresponding to FIG. 4(a) in the comparative example, (b) is a schematic diagram showing the side cross-sectional structure of a mold used to mold the relevant part, and (c) is a schematic diagram for explaining the molding method. 1A and 1B are diagrams for explaining a modified example of a composite container according to an embodiment of the present invention, in which (a) is a diagram corresponding to FIG. 4A in the modified example, (b) is a schematic diagram showing the side cross-sectional structure of a mold used to mold the relevant part, and (c) is a schematic diagram for explaining the molding method.

The composite container and the manufacturing method of the composite container according to the embodiment of the present invention will be described below with reference to the drawings.

1. Composite Container First, a schematic configuration of a composite container 100 of this embodiment will be described with reference to Figures 1 to 3. Note that Figure 1(a) is a front view (partial cross-sectional view) of the composite container 100, Figure 1(b) is a bottom view, Figure 2(a) is a top view, and Figure 2(b) is a side view (partial cross-sectional view). Note that the hatched portion in Figure 2(a) indicates an annular protruding rib 23f described later, and does not indicate a cross section.

As shown in FIG. 1(a), the composite container 100 has a bottom surface 11 and side surfaces 12, and is provided with a storage section 10 with an open top surface 13. The composite container 100 is a hybrid container made of different materials, with the storage section 10 being composed of a resin framework 20 and a paper tubular body 30. As shown in FIG. 1(b) and FIG. 2(a), the storage section 10 is configured in a cup shape, with the bottom surface 11 and top surface 13 each being a coaxial circle, and the top surface 13 having a larger diameter than the bottom surface 11.

The paper tubular body 30 is formed by joining the paper side panel 31 and the paper bottom panel 32 shown in FIG. 3 to the framework 20 to form the bottomed tubular storage section 10. Hereinafter, the line passing through the center of the bottom panel 11 and the top panel 13 is referred to as the central axis O, the direction along the central axis O is referred to as the axial direction, the direction perpendicular to the central axis O is referred to as the radial direction, and the direction around the central axis O is referred to as the circumferential direction. In addition, when the composite container 100 is placed in the state shown in FIG. 1, the bottom panel 11 side is referred to as the "lower" side, and the top panel 13 side is referred to as the "upper" side in the axial direction. Note that in FIG. 1(a) and FIG. 2(a), the cross-sectional view is taken from the right side of the central axis O as you face the figure. Below, the configuration of the framework 20 and the tubular body 30 will be described in order.

As shown in Figures 1(a) and 1(b) and 2(a) and 2(b), the framework 20 includes a side framework 21 that constitutes the framework of the side portion of the storage section 10, a bottom framework 22 that constitutes the framework of the bottom portion, and a top framework 23 that constitutes the framework of the top portion.

As shown in Figs. 1(a) and (b), the side frame 21 is composed of two support columns 21a and 21b, one end of which is connected to the bottom frame 22 and the other end of which is connected to the top frame 23. The two support columns 21a and 21b are arranged opposite each other across the central axis O. The connecting support column 21a and the reinforcing support column 21b protrude radially outward from the outer surface of the cylindrical body 30, i.e., the outer surface of the side paper panel 31, and are provided as convex ribs that extend from the bottom frame 22 to the top frame 23 along the axial direction.

Of the two support pillars 21a, 21b, the support pillar 21a corresponds to the joint portion in the present invention. The other support pillar 21b functions as a reinforcing portion for supplementing the strength (rigidity) of the storage portion 10. Hereinafter, the support pillar 21a is referred to as the joint support pillar 21a, and the other support pillar 21b is referred to as the reinforcing support pillar 21b. In the joint support pillar 21a, one end edge portion 31a and the other end edge portion 31b of the paper side panel 31 constituting the cylindrical body 30 are joined. In addition, the reinforcing support pillar 21b is joined (attached) to the outer surface of the cylindrical body 30 (paper side panel 31).

The bottom frame 22 forms the outer edge of the bottom surface 11 of the storage section 10. As shown in Figures 1 (a) and (b), the bottom frame 22 comprises a bottom annular frame 22a arranged on the bottom surface 11 side and a side annular frame 22b arranged on the side surface 12 side. The bottom annular frame 22a is configured as a flat ring with a thin axial thickness. The side annular frame 22b is thin in the radial direction and has a ring frame shape with a predetermined length in the axial direction. The bottom frame 22 has an approximately L-shaped cross section because the outer edge of the bottom annular frame 22a and the lower end of the side annular frame 22b are connected by the bottom bone joint 22c (see Figure 1 (a)).

The bottom frame 22 is connected to the joint support 21a and reinforcing support 21b of the side frame 21 by the connecting portion 22d. As shown in Figs. 1(a) and (b), the connecting portion 22d is provided from the bottom surface 11 side of the storage section 10 to the side surface 12 side of the bottom bone joint portion 22c, and is integrated with the joint support 21a on the side surface 12 of the storage section 10. Furthermore, as shown in Figs. 1 and 2, the outer edge of the bottom paper face body 32 is joined to the inner edge portion of the bottom annular frame 22a from the inner side of the bottom annular frame 22a, and the bottom end portion 31c of the side paper face body 31 is joined to the upper end portion of the side annular frame 22b from the outer surface side of the side annular frame 22b.

The top frame 23 forms the outer edge of the top surface 13 of the storage section 10. As shown in Figures 1(a) and 2(b), the top frame 23 comprises an inner frame 23a joined to the top edge 31d of the side paper panel 31, a flange 23b protruding outward at the upper end of the inner frame 23a, and an outer frame 23c suspended from the outer edge of the flange 23b. The inner frame 23a and the outer frame 23c each have a predetermined length in the axial direction and are configured as a ring frame with a thin radial thickness. In other words, the top frame 23 has a U-shaped cross-sectional shape that opens downward due to the inner frame 23a, the flange 23b, and the outer frame 23c. In the composite container 100 of this embodiment, the top frame 23 is configured to have a U-shape in cross section, which allows the thicknesses of the inner frame 23a, flange portion 23b, and outer frame 23c to be thin, making it easier to maintain the necessary strength even when the amount of resin is reduced.

In this embodiment, as shown in Figs. 1(a) and 1(b), four inner peripheral ribs 23d are provided at equal intervals along the inner peripheral surface at the lower end of the inner peripheral surface of the outer frame body 23c. The inner peripheral ribs 23d protrude radially inward from the inner peripheral surface of the outer frame body 23c and have a predetermined width in the circumferential direction. By providing the inner peripheral ribs 23d on the inner peripheral surface of the outer frame body 23c, the strength of the top frame body 23 can be increased. In addition, an outer peripheral rib 23e is provided around the entire circumference at the lower end of the outer peripheral surface of the outer frame body 23c so as to protrude radially outward. By providing these inner peripheral ribs 23d and outer peripheral ribs 23e, the strength required for the top surface 13 of the storage section 10 can be better maintained even when the thickness of the inner frame body 23a, the flange portion 23b, and the outer frame body 23c is reduced.

Furthermore, in this embodiment, as shown in Figs. 1(a), 2(a), and (b), an annular convex rib 23f that protrudes axially upward is provided on the top surface 13 of the flange portion 23b. The annular convex rib 23f is used as a contact ring for packing seal. In addition, when the composite container 100 is used as a refill container, the annular convex rib 23f can also be used to fit into an undercut provided at the joining portion for joining the composite container 100.

Next, the joining state between the framework 20 and the tubular body 30 (paper face pieces (31, 32)) will be described. In this embodiment, the tubular body 30 is formed by rolling a side paper face piece (paper face piece) 31 cut into a predetermined shape such as a sector as shown in FIG. 3(a) and joining one end edge 31a to the other end edge 31b with a joining support 21a to form a tube. The bottom paper face piece 32 has a shape (circular in this embodiment) that corresponds to the bottom shape of the storage section 10.

First, the joining state between both end edge portions 31a, 31b of the side paper face body 31 and the joining support portion 21a will be described. FIG. 4(a) is a diagram showing the joining state of the part, and is a cross-sectional view of the arrows A-A in FIG. 1(a). As shown in FIG. 4(a), the joining support portion 21a is interposed between one end edge portion 31a and the other end edge portion 31b of the side paper face body 31, and joins them. In this embodiment, the one end edge portion 31a and the other end edge portion 31b are embedded in the joining support portion 21a in a state where they are folded so as to protrude radially outward from the outer surface of the cylindrical body 30. By joining the two in this way, the inner and outer sides of each end edge portion 31a, 31b of the side paper face body 31 can also be covered with resin, and the entire end surface of the side paper face body 31 can be completely covered with resin.

In this embodiment, as shown in FIG. 4(a), one end edge 31a and the other end edge 31b of the paper side panel 31 are provided with a first fold 31e that forms a mountain fold when viewed from the outer surface side of the composite container 100, and a second fold 31f that forms a valley fold. In the paper side panel 31, the first fold 31e is disposed inside the second fold 31f with respect to the end faces of the end edges 31a and 31b. The first fold 31e and the second fold 31f are disposed approximately parallel to each other at a predetermined distance from the end faces (end edges) of the end edges 31a and 31b. By providing these first fold 31e and second fold 31f, the end edges 31a and 31b of the paper side panel 31 are folded so as to protrude radially outward from the outer surface of the cylindrical body 30 as described above.

In addition, in this embodiment, when the side paper panel 31 is unfolded (see FIG. 3(a)), the reinforcing support 21b is joined to the outer surface of the side paper panel 31 at approximately the midpoint between one end edge 31a and the other end edge 31b in the width direction (circumferential direction).

As shown in FIG. 1B, the bottom edge 31c of the side paper panel 31 is joined to the upper end of the side annular frame 22b of the bottom frame 22. The top edge 31d of the side paper panel 31 is joined to the lower end of the inner frame 23a of the top frame 23. In this embodiment, the four corners of the side paper panel 31 are rounded to form a so-called rounded corner shape. In this embodiment, the bottom edge 31c and the top edge 31d of the side paper panel 31 are joined to the bottom frame 22 and the top frame 23 without bending, unlike the one edge 31a and the other edge 31b. If the four corners of the side paper panel 31 have corners, they may peel off from the corners when the outer surface of the side paper panel 31 is joined to the inner surface of the side annular frame 22b of the bottom frame 22 and the inner frame 23a of the top frame 23. In this embodiment, by making the four corners rounded, the corners are less likely to peel off even when the paper side panel 31 is joined to the framework 20 on only one side.

The inner edge of the bottom annular frame 22a of the bottom frame 22 is joined to the outer edge of the circular bottom paper panel 32 shown in FIG. 3(b). The bottom frame 22 and top frame 23 are each joined to the outer side of the side paper panel 31. The bottom frame 22 is also joined to the outer side of the bottom paper panel 32.

In the composite container 100, the type of resin constituting the framework 20 is not particularly limited, but a wide variety of general-purpose resins, such as polypropylene (homopolymer, block copolymer, random copolymer), polyethylene (high density polyethylene, low density polyethylene, etc.), and polyethylene terephthalate resins, which are used as packaging container materials, can be used. In particular, when employing the manufacturing method described below, olefin-based resins such as polypropylene and polyethylene are more preferable.

The paper face (31, 32) constituting the cylindrical body 30 may be formed thin and flat by bonding together plant fibers or other fibers, and may be a laminated paper or composite paper made by laminating multiple sheets of so-called synthetic paper, gravure paper, or various plastics, or may be functional paper that has been given properties such as water resistance or oil resistance. The basis weight of the paper used can be designed as appropriate. In particular, when adopting the manufacturing method described below, it is more preferable to use a laminated paper that has been given properties such as water resistance or oil resistance by laminating an olefin resin sheet such as polyethylene resin or a polyethylene terephthalate resin sheet on the surface.

2. Manufacturing method of the composite container Next, a manufacturing method of the composite container 100 will be described. When manufacturing the composite container 100, the so-called insert molding method can be applied. A mold 50 (see FIG. 4(b)) corresponding to the framework 20 and a paper side panel 31 and a paper bottom panel 32 that have been cut to a predetermined shape in advance are prepared. Then, the paper side panel 31 and the paper bottom panel 32 are placed in the mold 50 as inserts at predetermined positions, and the mold 50 is filled with resin. The composite container 100 can be obtained by this method.

As shown in FIG. 4(b), the mold 50 has one mold member 51 and the other mold member 52 that are divided via a dividing surface, and the one mold member 51 and the other mold member 52 are combined to form a resin-filled portion that corresponds to the shape of the framework 20. FIG. 4(b) shows a side cross-sectional structure of the mold 50 near the joint support portion forming region 53 that has a shape corresponding to the joint support portion 21a as the resin-filled portion. Although not shown, the mold 50 also has other resin-filled portions, such as a reinforcing support portion forming region that has a shape corresponding to the reinforcing support portion 21b, a bottom frame body forming region that has a shape corresponding to the bottom frame body 22, and a top frame body forming region that has a shape corresponding to the top frame body 23.

As shown in FIG. 4(b), a paper face piece (31, 32) is placed at a predetermined position on the parting surface between one mold member 51 and the other mold member 52. Note that FIG. 4(b) shows the side paper face piece 31 placed at a predetermined position. The paper face pieces (31, 32) set at a predetermined position in the mold 50 are clamped between both mold members 51, 52.

At this time, as shown in Figure 4 (b), one end edge 31a and the other end edge 31b of the side paper panel 31 are each inserted into the joint support formation area 53. With one end edge 31a and the other end edge 31b of the side paper panel 31 inserted into the joint support formation area 53, resin is filled into the mold 50, whereby the one end edge 31a and the other end edge 31b of the side paper panel 31 are joined by the joint support 21a, and the side paper panel 31 is made into a cylindrical shape. Similarly, the bottom edge 31c, top edge 31d, and outer edge of the side paper panel 31 and bottom paper panel 32 are inserted into the bottom frame formation area and top frame formation area, respectively, and the side paper panel 31 is inserted into the reinforcing column formation area. When the mold 50 is filled with resin, these are joined together to obtain the composite container 100 in which the cylindrical body 30 and frame 20 are integrated.

As shown in FIG. 4(b), in this embodiment, in the joint support forming region 53, a convex portion 51a that protrudes toward the other mold member 52 is provided on the dividing surface of one mold member 51. In addition, a concave portion 51b is provided near the convex portion 51a on the dividing surface of one mold member 51. The convex portion 51a and the concave portion 51b are arranged in this order from the end face side of the end edges 31a and 31b with respect to both end edge portions 31a and 31b of the side paper panel 31.

Next, we will explain with reference to Figure 4(c). In Figure 4(c), the part below the dashed line shows the state in which the paper side panel 31 is placed on the mold 50, and the part above the dashed line shows the state in which the mold 50 has been filled with resin and the mold 50 has been removed. These correspond to Figures 4(b) and (a), respectively.

As shown in Figure 4(c), when the side paper panel 31 is placed in the mold 50, one end edge 31a of the side paper panel 31 is pushed up by the convex portion 51a toward the other mold member 52 (see the white arrow A in Figure 4(c)). A space is also created between the one end edge 31a of the side paper panel 31 and the concave portion 51b (see the white arrow B in Figure 4(c)). The same is true for the other end edge 31b. When resin is filled into the mold 50 in this state, the one end edge 31a and the other end edge 31b of the side paper panel 31 are pressed toward the dividing surface of one mold member 51 at the position indicated by the white arrow B by the resin filling pressure. At this time, since the dividing surface is provided with a convex portion 51a and a concave portion 51b, one end portion 31a and the other end portion 31b of the side paper panel 31 are folded into the concave portion 51b to form the first folded portion 31e having a mountain fold shape when viewed from the outer surface side. Also, the one end portion 31a and the other end portion 31b of the side paper panel 31 are folded by the concave portion 51b and the convex portion 51a to form the second folded portion 31f having a valley fold shape when viewed from the outer surface side (see the outlined arrow C in FIG. 4(c)). By providing such a convex portion 51a and a concave portion 51b on one of the mold members 51 of the mold 50, the side paper panel 31 cut into a predetermined shape such as a sector shape as shown in FIG. 3(a) is simply placed in the mold 50, and both end portions 31a, 31b of the side paper panel 31 are joined to the joint support portion 21a in a folded state. In other words, there is no need to fold both edge portions 31a, 31b of the side paper panel 31 into a specified shape and place it in the mold 50 in advance.

Here, polyolefin resins such as polypropylene or polyethylene terephthalate resins are used as the resin filling material to be filled into the mold 50, and laminated paper with a polyolefin resin sheet such as a polyethylene layer or a polyethylene terephthalate resin sheet is used as the paper side panels 31 and the paper bottom panel 32 on at least the surface that is joined to the framework 20. This allows the framework 20 and each paper panel (31, 32) to be thermally fused together during molding, and allows the framework 20 and each paper panel (31, 32) to be joined without the use of adhesives or the like.

According to the composite container 100 described above, the storage section 10 is mainly constituted by the paper tubular body 30, which is formed into a bottomed tubular shape by cutting the paper side panels 31 into a predetermined shape and providing a bottom paper panel 32, while the strength of the tubular body 30 is supplemented by the resin framework 20. Therefore, compared to when the entire storage section 10 is made of resin, the amount of resin used can be greatly reduced. Furthermore, the framework 20 only needs to be made thick enough to supplement the strength that is lacking with the paper tubular body 30 alone, so the amount of resin required for the framework 20 can be reduced.

In the above embodiment, one end edge 31a and the other end edge 31b of the side paper face 31 are interposed between them, and are joined so that the inner and outer sides of the end edges 31a and 31b are covered by the joint support 21a. Since the entire end faces of the end edges 31a and 31b are completely covered in this way, even when the composite container 100 is applied to a container for storing contents containing moisture such as food or liquid, it is possible to prevent moisture and the like from entering through the end face portion of the side paper face 31. Therefore, even if the end face portion of the side paper face 31 is a cut surface obtained by cutting a laminated paper, it is possible to prevent moisture and the like from entering through the cut surface and reducing the rigidity. In addition, even if the side paper face 31 is made of laminated paper in which multiple sheets are stacked, since the entire end face is completely covered, it is possible to suppress problems such as the laminated sheets easily peeling off from the surface and the joint strength between the one end edge 31a and the other end edge 31b and the joint support 21a being reduced. This allows the rigidity required for the paper tubular body 30 and the appearance of the composite container 100 to be maintained in a good condition, and the functionality required for the paper tubular body 30 to be maintained.

Furthermore, the composite container 100 can be manufactured by applying the insert molding method as described above. That is, the side paper panel 31 and bottom paper panel 32 of a predetermined shape are placed as inserts in the mold 50 for manufacturing the framework 20 at predetermined positions, and the resin filling section of the mold 50 is filled with resin, thereby manufacturing the composite container 100 having the integrated storage section 10 in which the resin framework 20 and the paper tubular body 30 are joined together.

In addition, in this embodiment, as described above, by simply providing a convex portion 51a and a concave portion 51b on the divided surface of one of the mold members 51 that constitutes the mold 50, one end edge portion 31a and the other end edge portion 31b of the side paper panel 31 can be folded by placing one end edge portion 31a and the other end edge portion 31b at a predetermined position on the divided surface of the mold 50 and filling it with resin, and the inner and outer surfaces of each end edge portion 31a, 31b can be covered from both sides by the joint support portion 21a. Thus, according to this embodiment, even when each end edge portion 31a, 31b is joined by the joint support portion 21a in a folded state, there is no need to fold each end edge portion 31a, 31b in advance, which improves manufacturing efficiency.

Therefore, according to the composite container 100 and the manufacturing method of the composite container 100 of the above embodiment, by combining the resin framework 20 and the paper tubular body 30, it is possible to reduce the amount of resin and improve manufacturing efficiency, and also to maintain a good joint state between the resin framework 20 and the top edge portion 31d of the paper tubular body 30.

Here, for example, the mold 60 shown in Fig. 5(b) and (c) is configured with a resin-filled portion corresponding to the shape of the framework 20, such as the joint support portion forming region 63, by combining one mold member 61 and the other mold member 62. The mold 60 has a configuration substantially similar to that of the mold 50 shown in Fig. 4(b) and (c), except that the one mold member 61 does not have the above-mentioned convex portion 51a and concave portion 51b. When such a mold 60 is used, the side paper panel 31 and the bottom paper panel 32 are placed in predetermined positions, and the resin-filled portion of the mold 60 is filled with resin, as in the above embodiment, to manufacture the composite container 100 having the storage portion 10 in which the resin framework 20 and the paper tubular body 30 are joined together and integrated.

However, in this case, as shown in FIG. 5(b), the side paper panel 31 is filled with resin in the joint support forming region 63 with the entire inner surface abutted against the divided surface of one of the mold members 61. Therefore, the outer surface of one end edge 31a and the other end edge 31b of the side paper panel 31 are covered with the resin filler that constitutes the joint support 64, but the resin filler does not sufficiently wrap around the inner surface as shown by the white arrow D in FIG. 5(c), making it difficult to cover the entire end surface of each end edge 31a, 31b with the resin filler. As a result, in the obtained composite container 100, the end surfaces of one end edge 31a and the other end edge 31b of the side paper panel 31 may be exposed and not covered with resin on the inner surface. If even a part of the end surface is exposed, if moisture adheres to the end surface, moisture, etc. may enter the inside of the side paper panel 31 from the end surface, causing a decrease in rigidity. Furthermore, if the side paper panel 31 is made of laminated paper made of multiple sheets, there is a risk of problems such as the laminated sheets peeling off from the surface or the joint strength of both end edges 31a, 31b decreasing. In contrast, in the composite container 100 of the above embodiment, both end edges 31a, 31b are joined in a state in which each end edge 31a, 31b is embedded in the joint support 21a, so such problems can be prevented.

The composite container 100 and the manufacturing method of the composite container 100 described above are merely one aspect of the composite container and the manufacturing method of the composite container according to the present invention, and the present invention is not limited to the above embodiment, and can be appropriately modified within the scope of the present invention. For example, in the above embodiment, the framework 20 is mainly joined to the outer surface side of the cylindrical body 30 (side paper face body 31, bottom paper face body 32), but the composite container according to the present invention is not limited to this aspect. For example, the framework 20 may be mainly joined to the inner surface side of the cylindrical body 30, and the framework 20 may not be arranged on the outer surface side of the storage section 10, or a part of the framework 20 may be joined from the outer surface side of the cylindrical body 30, and the rest may be joined from the inner surface side of the cylindrical body 30, and various other aspects can be applied.

By joining the framework 20 mainly to the outer surface of the tubular body 30 as in the above embodiment, the framework 20 does not protrude from the inside of the storage section 10. This prevents, for example, the contents from adhering to the joint between the framework 20 and the tubular body 30 when cosmetics such as yogurt, pudding, or cream are stored in the storage section 10, making it difficult to remove the contents cleanly.

On the other hand, if the framework 20 is joined mainly from the inner surface side of the cylindrical body 30 and configured so that the framework 20 is covered by the cylindrical body 30, it is possible to make the framework 20 invisible from the outside.
In the above embodiment, the side framework 21 is composed of the joint support parts 21a and the reinforcing support parts 21b, but if the number of reinforcing support parts 21b constituting the side framework 21 is increased in accordance with the strength (rigidity) required for the cylindrical body 30, the appearance may be impaired if the number of framework bodies 20 on the outer surface of the cylindrical body 30 increases. In such a case, it is preferable to join the two together so that the framework bodies 20 are disposed mainly inside the cylindrical body 30.
Furthermore, when the composite container 100 is used as a container for use in a bathroom or the like, water droplets may adhere to the outer surface of the composite container 100 due to condensation or the like. If the framework 20 is disposed on the outside of the composite container 100, water droplets adhering to the framework 20 may remain attached to the outer surface of the composite container 100, which may facilitate water infiltration from the edge portions 31a, 31b of the paper side panel 31, etc. Therefore, for containers used in environments where water droplets may adhere, such as a bathroom, or where condensation is likely to occur due to the influence of atmospheric humidity, it is preferable to dispose the framework 20 inside the cylindrical body 30.

In this way, depending on the contents and the desired appearance of the composite container 100, it is possible to appropriately select whether to place the framework body 20 inside or outside the cylindrical body 30.

In the above embodiment, one end edge 31a and the other end edge 31b of the side paper panel 31 are folded so as to protrude radially outward, and both end edges 31a, 31b are joined by the joining support 21a so as to cover the outer and inner surfaces. However, if the framework 20 is to be joined so as to be positioned mainly inside the cylindrical body 30, for example, one end edge 31a and the other end edge 31b of the side paper panel 31 can be folded so as to protrude radially inward, and joined from the inner side of the side paper panel 31 by the joining support 21a so as to cover the outer and inner surfaces.

Furthermore, when folding one end edge portion 31a and the other end edge portion 31b of the side paper panel 31, for example, as shown in Figure 6 (a), a folding portion 31g may be formed at a position spaced a predetermined distance from each end edge portion 31a, 31b, and the folding portion may be folded so as to protrude from the outer surface of the tubular body 30 approximately parallel to each end edge portion 31a, 31b. In this case, as shown in FIG. 6(b), a mold 70 having one mold member 71 and the other mold member 72 is used, and as in the above embodiment, one end portion 31a and the other end portion 31b of the side paper panel 31 are inserted into the joint support forming region 73, and the protrusion 71a provided on the dividing surface of the one mold member 71 in the joint support forming region 73 pushes the one end portion 31a and the other end portion 31b toward the other mold member 72, and resin is filled in the state in which both end portions 31a, 31b of the side paper panel 31 are joined to the joint support 21a in a folded state.

In the above embodiment, an example was described in which both end edges 31a, 31b of the side paper panel 31 are folded and both the inner and outer sides are covered by the joint support 21a to join the two, but in the above composite container 100, both end edges 31a, 31b of the side paper panel 31 do not necessarily need to be folded. When the side paper panel 31 is rolled into a cylindrical shape, any form is acceptable as long as one end edge 31a and the other end edge 31b are interposed therebetween and are joined by a joint (joint support 21a) that covers the entire end surface of the side paper panel 31 at the one end edge 31a and the other end edge 31b.

In addition, in the above embodiment, the rounded corners of the paper side panel 31 and the circular bottom panel 32 are joined to the bottom frame 22 and top frame 23, respectively, making the paper side panel 31 and the bottom panel 32 less likely to come off at the joints with the bottom frame 22 and top frame 23. However, it is also preferable to join these parts so that their inner and outer sides are covered by each frame (22, 23) in the same way as the one end 31a and the other end 31b. In addition, the joint end may be folded and embedded in the frame to join and integrate the frame 20 and each paper panel (31, 32).

In the above embodiment, the storage section 10 is formed in a cup shape with its bottom surface 11 and top surface 13 being circular, but the specific shape of the storage section 10 is not particularly limited. For example, it may be formed in a deep dish shape or a bottle shape, and the shapes of the bottom surface 11 and top surface 13 are not limited to circles, but may be square, rectangular, polygonal, etc.

In the above embodiment, one side paper panel 31 is rolled and one end 31a is joined to the other end 31b, but the number of side paper panels 31 used to form the side 12 of the storage section 10 is not particularly limited, and two or more sheets may be used and the ends of each side paper panel 31 joined to obtain a tubular body 30. Also, one side paper panel 31 may have a cut portion, and the cut edges may be joined using a part of the side framework 21 as in the above embodiment. In this way, storage sections 10 of various shapes can be formed.

In addition, in the above embodiment, the bottom surface 11 of the storage section 10 is formed using the bottom frame assembly 22 and the bottom paper panel 32, but the shape of the bottom frame assembly 22 is not particularly limited. The bottom frame assembly 22 may be provided with reinforcing ribs such as a cross, and the entire bottom surface 11 may be formed from a resin bottom material, and the configuration of the bottom surface 11 is not particularly limited. When the entire bottom surface 11 is formed from a resin bottom material, there is no need to use the bottom paper panel 32, and such an embodiment is also included in the composite container of the present invention.

In the above embodiment, the side framework 21 is composed of the connecting support 21a and the reinforcing support 21b, but in the composite container of the present invention, it is sufficient that the framework has a joint between one end edge and the other end edge of the paper panel to join them, and the rest is optional. In other words, if the cylindrical body 30 itself meets the required strength, the reinforcing support 21b is not necessary, and the side framework 21 may be composed only of the connecting support 21a. In addition, the specific configurations of the side framework 21, bottom framework 22, and top framework 23 are also optional, as long as any of them has the joints referred to in the present invention.

10: Storage section 11: Bottom surface 12: Side surface 13: Top surface 20: Frame body 21: Side frame body 21a: Joint support section (joint section)
21b : Reinforcing support section 22 : Bottom frame body 22a : Bottom annular frame 22b : Side annular frame 22c : Bottom frame joint section 22d : Connection section 23 : Top frame body 23a : Inner frame body 23b : Flange section 23c : Outer frame body 23d : Inner peripheral rib 23e : Outer peripheral rib 23f : Annular convex rib 30 : Cylindrical body 31 : Side paper panel 31a : Edge 31b : Edge 31c : Bottom edge 31d : Top edge 31e : First folded section 31f : Second folded section 31g : Folded section 32 : Bottom paper panel 50 : Mold 51 : Mold member 51a : Convex section 51b : Concave section 52 : Mold member 53 : Joint support section forming area 60 : Mold 61 : Mold member 62 : Mold member 63 : Joint support formation area (joint formation area)
64: Joint support portion 70: Mold 71: Mold member 71a: Convex portion 72: Mold member 100: Composite container O: Central axis

Claims (5)

The container has a bottom surface and a side surface, and is configured using a resin framework and a paper tubular body.
The paper cylinder is one or more paper faces formed into a cylindrical shape,
The framework has a joint portion interposed between one end edge portion and another end edge portion of the paper panel and covering the entire end faces of the one end edge portion and the other end edge portion,
A composite container , wherein the one end portion and the other end portion are folded to protrude from the outer surface of the cylindrical body and are embedded within the joint portion . The framework includes a bottom framework that constitutes an outer edge of the bottom surface, a top framework that constitutes an outer edge of the top surface of the storage section, and a side framework that includes the joint and is connected to the bottom framework and the top framework,
The side surface of the storage section is composed of the side framework and a side paper panel that is cylindrical in shape by joining the one end portion and the other end portion to the joint portion,
The bottom surface of the storage section is composed of the bottom frame and a bottom paper surface body whose outer edge portion is joined to the bottom frame,
2. The composite container according to claim 1 , wherein the bottom edge of said paper tube is joined to said bottom frame body, and the top edge is joined to said top frame body. A method for producing the composite container according to claim 1 or 2 , comprising the steps of:
A mold has one mold member and another mold member that are separated via a separation surface, and the one mold member and the other mold member are combined to form a resin-filled portion having a shape corresponding to the framework body,
A method for manufacturing a composite container in which the paper face piece is placed between one of the mold members and the other of the mold members so that the edge portion of the paper face piece is inserted into a joint forming area in the resin filled portion having a shape corresponding to the joint, and the paper face piece is clamped between both mold members, and resin is filled into the resin filled portion, thereby joining the one edge portion and the other edge portion of the paper face piece at the joint, thereby obtaining the composite container in which the framework and the tubular body are integrated. a protrusion protruding from the parting surface of the one mold member toward the other mold member is provided within the joint formation region,
The method for manufacturing a composite container according to claim 3 , wherein the resin is filled in the resin filling section while the edge portion of the paper surface piece is pushed up toward the other mold member by the convex portion. a recess is provided in the parting surface of the one mold member near the protrusion at a position where the edge portion is disposed in the joint formation region, and the protrusion and the recess are disposed in this order from the end face side of the edge portion,
The method for manufacturing a composite container according to claim 4 , wherein when the resin is filled into the resin filling section, the edge section is bent by a resin filling pressure and the concave and convex sections.

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