Composite container and method of manufacturing the composite container

Abstract

To maintain a function required for a storage part while remarkably reducing a resin amount and improving manufacturing efficiency, and to provide a new container having the storage part whose face is joined by a resin rib and a new manufacturing method related to the container.SOLUTION: A composite container 100 has a storage part 10 constituted by joining one end part 31a and the other end part 32c of paper faces 31, 32 by a resin joining rib 21. At least one out of the one end part 31a and the other end part 32c has a recessed part 31b recessed toward the inside of the face. The joining rib 21 has a predetermined width (Wn), and is provided with a normal width region AN where the one end part 31a and the other end part 32c are joined so that both faces of them are covered in a state where they are separated from each other by a predetermined distance D1 in the part other than the recessed part 31b, and a widened region AW where both the faces of them are covered in the recessed part 31b and they are widened corresponding to a recessed amount of the recessed part 31b with respect to the predetermined width (Wn).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a composite container and a method for manufacturing a composite container. [Background technology]

[0002] 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. Furthermore, composite containers that combine plastic containers with paper components have also been proposed.

[0003] For example, Patent Document 1 proposes a composite container that combines a resin container with a paper sleeve (reinforcing member). In this composite container, a thin-walled portion having a thickness of 0.01 mm to 0.09 mm is provided in the body of the resin container to reduce the amount of resin. However, providing such a thin-walled portion in the body makes the body easily deformed and difficult to grip. Therefore, this resin container is provided with 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, with the thin-walled portion positioned closer to the bottom than the thick-walled portion. The body of the resin container is then inserted into a cylindrical paper sleeve, and the sleeve is supported by the protrusion. This allows for easy attachment of the resin container and the paper sleeve, and the sleeve reinforces the rigidity of the resin container, which is reduced by the thin-walled portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-116122 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the composite container disclosed in Patent Document 1, the amount of resin in the body is reduced by providing rigidity with a paper sleeve. However, the body has a thick-walled portion at the top, and the bottom is also thicker than the thin-walled portion to maintain a certain level of strength. Therefore, the resin portion is still large, and further reduction in the amount of resin used is required.

[0006] Furthermore, the composite container requires the resin container and the paper sleeve to be prepared separately, and then the paper sleeve must be attached to the resin container. The resin container is produced by blow molding a preform, and the paper sleeve is produced by rolling a piece of paperboard or the like cut into a predetermined shape including a main body and a margin, and then bonding the main body and the margin with an adhesive or the like. As such, the manufacturing process for the conventional composite container is complicated, and improvements in manufacturing efficiency are required.

[0007] Furthermore, the paper sleeve uses laminated paper or the like, on the surface of which a functional film having functions such as water resistance is laminated. Such composite containers contain contents containing moisture, such as food. Because the cut surface of the paper sleeve is not covered with a functional film, moisture may penetrate through the cut surface, causing the paper sleeve to become swollen. In such cases, the paper sleeve may not be able to maintain the rigidity required. Furthermore, 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.

[0008] Therefore, the object of the present invention is to provide a composite container and a manufacturing method thereof that can significantly reduce the amount of resin used and improve manufacturing efficiency while maintaining the functionality required for the container portion. Also, to provide a new container having a container portion in which the face piece is joined with a resin rib, and a new manufacturing method for the container. [Means for solving the problem]

[0009] In order to solve the above problems, the composite container of the present invention is a composite container having a storage section formed by joining one end and the other end of a paper panel with a resin joining rib, and at least one of the one end and the other end has a recess that is recessed into the inside of the surface, and the joining rib has a predetermined width and has a constant width region that joins the one end and the other end so as to cover both sides with a predetermined distance D1 between them in the part other than the recess, and a widened region that covers both sides in the recess and is widened from the predetermined width in accordance with the amount of recess of the recess, and the joining rib has a top surface rib that forms the outer edge of the top surface of the storage section, and the top surface rib has an inner frame body that is joined to the top end of the side paper panel that forms the side of the storage section, a flange portion that protrudes outward at the upper end of the inner frame body, and an outer frame body that hangs down from the outer edge of the flange portion. An inner peripheral rib is provided along the inner peripheral surface at a lower end of the inner peripheral surface of the outer frame body. Characterized by 。 Ma In the composite container according to the present invention, it is preferable that a peripheral rib be provided at the lower end of the outer peripheral surface of the outer frame so as to protrude radially outward.

[0010] In the composite container of the present invention, it is preferable that the one end is the outer peripheral end of a bottom paper face piece that constitutes the bottom surface of the storage section, the other end is the bottom end of a side paper face piece that constitutes the side surface of the storage section, the recess is provided on the outer peripheral end of the bottom paper face piece or the bottom end of the side paper face piece, and the joining rib is a bottom rib that joins the outer peripheral end of the bottom paper face piece and the bottom end of the side paper face piece to form the outer edge of the bottom surface.

[0011] In the composite container of the present invention, the side of the storage section has a side rib that joins one side end and the other side end of one or more of the side paper face pieces from both sides while the two sides are spaced a predetermined distance D2 apart, and it is preferable that the side rib and the bottom rib are joined in the widened region.

[0012] In the composite container according to the present invention, the joining rib is preferably an injection-molded member formed by injecting a resin material from a position corresponding to the widened region.

[0014] In order to solve the above problems, the manufacturing method of the composite container of the present invention is a manufacturing method of a composite container for manufacturing a composite container having a storage section configured by joining one end and the other end of a paper panel with a joining rib made of resin, at least one of the one end and the other end has a recess that is recessed into the inside of the surface, the joining rib has a predetermined width and has a constant width region that joins the one end and the other end so that both sides are covered with a predetermined distance D1 between them in the part other than the recess, and a widened region that covers both sides in the recess and is widened from the predetermined width in accordance with the amount of recess of the recess, the joining rib has a top surface rib that forms the outer edge of the top surface of the storage section, the top surface rib has an inner frame body that is joined to the top end of the side paper panel that forms the side of the storage section, a flange portion that protrudes outward at the upper end of the inner frame body, and an outer frame body that hangs down from the outer edge of the flange portion, an inner peripheral rib is provided along a lower end of an inner peripheral surface of the outer frame body, A mold is used in which a resin filling portion having a shape corresponding to the joining rib is formed, the paper face piece is placed at a predetermined position in the mold with the one end and the other end spaced a predetermined distance D1 apart, a position corresponding to the widened region of the resin filling portion is designated as a gate portion, and resin material is filled into the resin filling portion from the gate portion. [Effects of the Invention]

[0016] According to the composite container of the present invention, the storage section is composed of a paper facepiece and a resin joining rib, which allows for a significant reduction in the amount of resin used compared to when the entire storage section is composed of resin. Furthermore, the joining rib joins one end of the paper facepiece to the other end so as to cover both sides. Therefore, even when the composite container is used as a container for storing contents containing moisture, such as food, or liquid, it is possible to prevent moisture from penetrating the inside of the paper facepiece through the joint between the one end and the other end, which would cause problems such as a decrease in the rigidity of the paper facepiece.

[0017] Furthermore, when manufacturing the composite container according to the present invention, for example, an injection molding method (insert molding method) can be applied. That is, by placing the paper face piece at a predetermined position in a mold, inserting one end and the other end to be joined into the resin-filled portion of the mold, and then filling the mold with resin material, the two can be joined and integrated while covering both sides of the ends.

[0018] In this case, as in the composite container of the present invention, by providing a widened region in the joining rib and a recess in the paper face piece, and by designing the position of the mold corresponding to the widened region as a gate portion, it becomes easy to design the gate diameter so that the resin material can be injected smoothly into the resin filling portion, even when the constant width region is narrow. Furthermore, by applying the manufacturing method for a composite container of the present invention, by positioning one end and the other end of the paper face piece at a position spaced a predetermined distance D3 or more from the gate portion, it is possible to prevent the filling pressure of the resin material from being directly applied to these ends, thereby preventing problems such as bending of these ends during molding. Therefore, the manufacturing method for a composite container of the present invention allows for the production of composite containers made of different materials with high yield using a method similar to conventional injection molding (insert molding).

[0019] As described above, the composite container and the manufacturing method of the composite container according to the present invention can reduce the amount of resin used and improve manufacturing efficiency, while maintaining the functionality required for the container. Also, a new container having a container part in which the face pieces are joined with resin ribs and a new manufacturing method for the container are provided. [Brief explanation of the drawings]

[0020] [Figure 1] 1A and 1B are diagrams showing a composite container according to an embodiment of the present invention, in which (a) is a top view and (b) is a front view, part of which shows the cross section taken along line BB in FIG. 1A (and FIG. 3A). [Figure 2] 2A and 2B are plan views showing the paper face pieces that make up the storage section of the composite container shown in FIG. 1, where (a) shows the bottom paper face piece that makes up the bottom surface of the storage section, and (b) shows the side paper face piece that makes up the side surface of the storage section. [Figure 3] 2A and 2B are diagrams for explaining the composite container shown in FIG. 1, where (a) is a cross-sectional view taken along line AA in FIG. 1, and (b) is a bottom view of the composite container. [Figure 4] 2 is a diagram for explaining the constant width region AN and the widened width region AW, etc., referred to in the present invention, and is a diagram showing a part of the bottom surface of the composite container shown in FIG. 1. FIG. [Figure 5] 3(a) is a cross-sectional view taken along CC in FIG. 3(a), and FIG. 3(b) is a cross-sectional view taken along DD in FIG. 3(a), with respect to the composite container shown in FIG. [Figure 6] 2A and 2B are schematic diagrams for explaining the manufacturing method of the composite container shown in FIG. 1, in which (a) shows the state before the resin material is filled into the mold, and (b) shows the state when the resin material is filled into the mold. [Figure 7] 1(a) and 1(b) are diagrams showing a composite container as a comparative example of the present invention, in which (a) is a side view thereof, part of which shows a cross section at the same position as in FIG. 1(b), and (b) is a top view thereof. [Figure 8] FIG. 7 is a view showing a part of the bottom surface of the composite container shown in FIG. 6 as a comparative example. [Figure 9] 10A and 10B are schematic diagrams for explaining a manufacturing method of a composite container of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0021] A composite container and a method for manufacturing a composite container according to an embodiment of the present invention will be described below with reference to the drawings.

[0022] 1. Composite containers First, the schematic configuration of a composite container 100 of this embodiment will be described with reference to FIGS. 1 to 3. As shown in FIG. 1(b), the composite container 100 includes a storage section 10 having a bottom surface 11 and side surfaces 12 and an open top surface 13. The storage section 10 is configured into a bottomed, cylindrical cup-like shape by joining the ends of the paper panels (bottom paper panel 31, side paper panel 32) that should be joined (the outer peripheral edge 31a of the bottom paper panel 31 and the bottom edge 32c of the side paper panel 32, and one side edge 32a and the other side edge 32b of the side paper panel 32 (see also FIGS. 2(a) and 2(b))) with joining ribs 20 so as to cover both sides. In this way, the composite container 100 is configured as a hybrid container made of different materials, namely, a resin material and a paper material.

[0023] As shown in FIGS. 1(a) and 3(b), the bottom surface 11 and the top surface 13 each have a coaxial circular shape, and as shown in FIGS. 1(a) and 1(b), the top surface 13 has a larger diameter than the bottom surface 11. Hereinafter, a line passing through the centers of the bottom surface 11 and the top surface 13 is referred to as the central axis O, a direction along the central axis O is referred to as the axial direction, a direction perpendicular to the central axis O is referred to as the radial direction, and a direction circumferentially around the central axis O is referred to as the circumferential direction. The vertical direction refers to the axial direction. Furthermore, when the composite container 100 is placed in the state shown in FIG. 1, the bottom surface 11 side is referred to as the "lower" side, and the top surface 13 side is referred to as the "upper" side in the axial direction. Note that FIG. 1(b) shows a cross section to the right of the central axis O.

[0024] First, the paper face piece will be described. The bottom surface 11 of the storage section 10 includes a bottom paper face piece 31 shown in FIG. 2(a), and the side surface 12 includes a side paper face piece 32 shown in FIG. 2(b). As shown in FIG. 2(a), the bottom paper face piece 31 has a roughly circular shape corresponding to the shape of the bottom surface 11, and a recess 31b is provided at a portion of the bottom paper face piece 31 at the outer peripheral edge 31a, recessed into the inside of the face. FIG. 2(a) illustrates the recess 31b as having a roughly semicircular shape cut out from the outer peripheral edge 31a of the bottom paper face piece 31, but the recess 31b may have a roughly V-shaped cutout at the inner side of the face at the outer peripheral edge 31a, for example, or a roughly rectangular cutout; the shape of the recess 31b is not particularly limited.

[0025] On the other hand, the side paper face piece 32 has a roughly fan-shaped configuration as shown in Fig. 2(b). As shown in Fig. 3(a), one side end 32a and the other side end 32b of the side paper face piece 32 are joined by the side rib 22, thereby forming a cylindrical shape as shown in Fig. 1(b).

[0026] Next, the joining rib 20 will be described. In this embodiment, the joining rib 20 is joined to at least one of the bottom paper panel 31 and the side paper panel 32, and has a bottom rib 21, a side rib 22, a top rib 23, and a reinforcing rib 24, as shown in Figure 1(b). The joining rib referred to in the present invention mainly corresponds to the bottom rib 21 in the composite container 100 of this embodiment.

[0027] As shown in Figures 1(a) and (b), the bottom rib 21 forms the outer edge of the bottom surface 11 of the storage section 10, and joins the outer peripheral edge 31a of the bottom paper panel 31 and the bottom edge 32c of the side paper panel 32. As shown in Figure 1(b), the bottom rib 21 has a bottom annular frame 21a provided on the bottom surface 11 side, which covers both sides of the outer peripheral edge 31a of the bottom paper panel 31, and a side annular frame 21b provided on the side surface 12 side, which covers both sides of the bottom edge 32c of the side paper panel 32. The bottom annular frame 21a and the side annular frame 21b are connected together by connecting portions 21c, and are configured as a ring-shaped frame with a generally L-shaped cross section as a whole.

[0028] Next, the bottom rib 21 will be further described with reference to Figure 4. Figure 4 is a bottom view showing a part of the bottom surface 11 of the storage section 10. In Figure 4, the outer peripheral edge 31a of the bottom paper panel 31 and the bottom edge 32c of the side paper panel 32 are indicated by dashed lines. As shown in Figure 4, the bottom rib 21 has a constant width region A having a predetermined width Wn along the outer edge of the bottom surface 11. N and a widened region A having a width widened at a position corresponding to the recess 31b provided on the bottom paper surface body 31. W The bottom rib 21 has a constant width region A between the vicinity of one side end 32a of the side paper face body 32 and the other side end 32b. N The steady width region A N In the case of the present invention, the outer peripheral edge 31a of the bottom paper panel 31 and the bottom edge 32c of the side paper panel 32 are covered and joined together with a predetermined distance D1 between them.

[0029] Widening area A W is the constant width region A N and widening area A W and steady-state width region A N Widening area A is integrated with W The constant width region A is determined depending on the amount of depression of the recess 31b into the surface. N Insert an area wider than the above. Widened area A W In the widened region A, both sides of the recess 31b are covered. W In this case, the outer peripheral edge 31a of the recess 31b and the bottom edge 32c (one side edge 32a or the other side edge 32b) of the paper side panel 32 are spaced apart by more than the above-mentioned predetermined distance D1.

[0030] By the way, in FIG. 4, this widening region A WThe approximate circle shown in the figure is a gate mark 40 that was created when the joining rib 20 was manufactured by injection molding (insert molding). In an injection-molded product, a mark of a gate portion 54 (see FIG. 6) for injecting a resin material into a mold 50 during injection molding remains as the gate mark 40. Note that FIG. 3(b) also shows the gate mark 40. However, although the gate mark 40 is shown by a solid line in FIGS. 3(b) and 4, in an actual composite container 100 or a composite container according to the present invention, the gate mark 40 does not have to be circular and may have another shape, such as a square, and does not necessarily have to be clearly visible.

[0031] As shown in Figure 4, in the composite container 100 of this embodiment, the outer peripheral edge 31a of the bottom paper face piece 31 and the bottom edge 32c of the side paper face piece 32 are not positioned inside the gate mark 40 when viewed from the bottom, and each edge (31a, 32c) of these paper face pieces (31, 32) is positioned outside the outer edge of the gate mark 40. In this embodiment, each edge (31a, 32c) of the paper face pieces (31, 32) is positioned at a distance of at least a predetermined distance D3. However, D4 in Figure 4 indicates the distance between the gate mark 40 and the other side edge 32b of the side paper face piece 32, and the distance between the gate mark 40 and one side edge 32a of the side paper face piece 32 is also the same distance as D4, so an example has been shown where D4 ≥ D3. However, the separation distance D4 may be less than the predetermined distance D3, and although there are no particular limitations on the relationship between the separation distance D4 and the predetermined distance D3, it is preferable that D4≧D3 as shown in Fig. 4. However, if the separation distance D4 is too large, the amount of resin required for the side rib 22 increases, so the separation distance D4 is preferably within a range of 0.1 mm to 2.5 mm, and more preferably within a range of 0.5 mm to 2.0 mm.

[0032] As shown in Figures 1(b) and 5(a), one end of the side rib 22 is connected to the bottom rib 21, and the other end is connected to the top rib 23. However, Figure 5(a) is a cross-sectional view taken along CC in Figure 3(a). As shown in Figure 3(a), one side end 32a and the other side end 32b of the side paper face piece 32 are joined by the side rib 22, with a predetermined distance D2 between them as shown in Figure 4. Furthermore, both sides of one side end 32a and the other side end 32b of the side paper face piece 32 are covered by the side rib 22. Furthermore, as shown in Figures 1(b) and 5(a), the side rib 22 is connected to the widened region A of the bottom rib 21. W In addition, the side ribs 22 are disposed outside the gate marks 40 when viewed from the bottom.

[0033] As shown in Figure 3(a) and other figures, a reinforcing rib 24 is provided on the side surface 12 of the storage section 10 at a position opposite the side rib 22 across the central axis O. In the example shown in Figure 3(a) and other figures, the reinforcing rib 24 is joined by being adhered to the outer surface of the side paper face piece 32, and like the side rib 22, one end is connected to the bottom rib 21 and the other end is connected to the top rib 23. However, the reinforcing rib 24 may also be adhered to the inner surface of the side paper face piece 32 instead of the outer surface of the side paper face piece 32.

[0034] In the example shown in FIG. 3(a), the side ribs 22 and the reinforcing ribs 24 protrude radially outward from the outer surface of the paper side panel 32, forming convex ribs extending from the bottom rib 21 to the top rib 23. As shown in FIG. 3(a), the side ribs 22 also protrude radially inward. However, this is not limited to the illustrated example, and the side ribs 22 may be arranged to protrude only radially outward from the outer surface of the paper side panel 32, or may be arranged to protrude only radially inward from the inner surface. The reinforcing ribs 24 are also not limited to the illustrated example, and may be arranged on the inner surface of the paper side panel 32 and protrude radially inward from the inner surface, or may be arranged on both sides of the paper side panel 32. In the example shown in FIG. 3(a), the reinforcing ribs 24 may be replaced with the side ribs 22, and the storage section 10 may be constructed by joining two paper side panels 32. In this case, too, as shown in Figure 3(a), the side ribs 22 may be used on both the outer and inner sides of the side paper panel 32, protruding radially inward and outward, or may protrude only on one side.

[0035] As shown in Figure 3(a) and Figures 5(a) and (b), the side surface 12 of the storage section 10 is composed only of the side paper panel 32 except for the positions where the side ribs 22 and reinforcing ribs 24 are provided.

[0036] By joining the side ribs 22 as described above when forming the paper side face piece 32 into a cylindrical shape, the side ribs 22 can function not only as a simple joining member but also as a reinforcing member for supplementing the strength (rigidity) of the storage section 10. Furthermore, by providing the reinforcing ribs 24 as in this embodiment, the strength of the storage section 10 can be further improved. The reinforcing ribs 24 are joined (adhered) to the outer surface of the paper side face piece 32 at a position approximately midway between one side end 32a and the other side end 32b of the paper side face piece 32.

[0037] The top rib 23 forms the outer edge of the top surface 13 of the storage section 10. As shown in Figures 1(a), (b), and 3(b), the top rib 23 comprises an inner frame 23a joined to the top end 32d of the side paper panel 32, a flange 23b protruding outward from 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 ring frames with a thin radial thickness. In other words, the top rib 23 has a generally U-shaped cross section that is open downwards and is formed by the inner frame 23a, the flange 23b, and the outer frame 23c. In the composite container 100 of this embodiment, the top surface rib 23 is configured to have an approximately U-shaped cross section, which allows the thickness of the inner frame body 23a, flange portion 23b, and outer frame body 23c to be made thin, making it easier to maintain the required strength even when the amount of resin is reduced.

[0038] In this embodiment, as shown in FIGS. 1(b) and 3(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 rib 23 can be increased. Furthermore, when the composite container 100 is used as a refill container, the inner peripheral ribs 23d can be used to fit into undercuts provided at the joint portion. Furthermore, an outer peripheral rib 23e is provided around the entire 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, flange portion 23b, and outer frame body 23c is reduced.

[0039] 1(a) and 1(b), an annular convex rib 23f that protrudes upward in the axial direction is provided on the top surface 13 of the flange portion 23b. The annular convex rib 23f is used as a contact ring for a packing seal.

[0040] Next, the constituent materials of the composite container 100 will be described. In the composite container 100, the type of resin constituting the joining rib 20 is not particularly limited, but a wide variety of general-purpose resins used as packaging container materials, such as polypropylene (homopolymer, block copolymer, random copolymer), polyethylene (high-density polyethylene, low-density polyethylene, etc.), and polyethylene terephthalate resin, can be used. In particular, when employing the manufacturing method described below, it is more preferable to use an olefin resin such as polypropylene or polyethylene as the constituent material of the joining rib 20.

[0041] The paper face pieces (31, 32) that make up the storage section 10 may be thin and flat formed by agglutinating plant fibers or other fibers, and may be laminated or composite paper made by laminating multiple sheets of synthetic paper, gravure paper, or various plastics, or functional paper that has been given properties such as water resistance or oil resistance. The basis weight of the paper used can be designed appropriately. In particular, when using the manufacturing method described below, it is more preferable to use 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.

[0042] In the present invention, the container 10 is constructed by primarily joining paper face pieces (31, 32) with the joining rib 20 to reduce the amount of resin. However, the paper face pieces (31, 32) can also be replaced with resin face pieces, such as the film used to package each main container. In this case, the amount of resin can also be reduced by replacing most of the bottom surface 11 and side surfaces 12 of the container 10 with thin resin films. In this case, a multilayer film can be used in which a barrier layer (such as an EVOH layer) is used as an intermediate layer and an olefin-based resin sheet such as a polyethylene resin or a polyethylene terephthalate resin sheet is laminated on the inner and outer surfaces of the barrier layer. This can also be manufactured using a method similar to the composite container manufacturing method described below. Furthermore, since barrier layers generally contain hydrophilic groups such as OH groups, contact with moisture (including water vapor) is undesirable. In this case, covering the end surfaces with the joining rib 20 as described above can prevent the barrier layer from coming into contact with moisture.

[0043] 2. Manufacturing method of composite container Next, a method for manufacturing the composite container 100 will be described. When manufacturing the composite container 100, an injection molding method can be used, and a so-called insert molding method can be applied. A mold 50 (see FIG. 6(a)) having a resin-filled portion 51 corresponding to the shape of the joining rib 20 and a clamping portion 52 for clamping the paper face pieces (31, 32) is prepared, along with the bottom paper face piece 31 and the side paper face pieces 32 (see FIG. 2) that have been pre-cut to a predetermined shape. The bottom paper face piece 31 is provided with the recess 31b. The mold 50 is configured to be separable as needed, and the clamping portion 52 may be formed using a dividing surface other than the resin-filled portion 51 of the mold 50.

[0044] 6(a) shows a side cross section of the mold 50, which corresponds to the cross section BB in FIG. 3(a). The mold 50 is provided with a runner portion 53 for injecting molten resin material into the resin filling portion 51, and a gate portion 54 which serves as an inlet for the resin material from the runner portion 53 to the resin filling portion 51. In this embodiment, the widened region A of the bottom rib 21 WA runner portion 53 and a gate portion 54 are provided at positions corresponding to the above. The runner portion 53 is connected to an injection molding machine (not shown) and a distribution path for the resin material via a spool portion (also not shown).

[0045] The bottom paper face piece 31 and the side paper face pieces 32 are placed in predetermined positions in the mold 50 as inserts, and are clamped by the clamping section 52. Figures 6(a) and (b) show the state in which the bottom paper face piece 31 is placed in a predetermined position in the mold 50. As shown in Figure 6(a), the outer peripheral end 31a of the bottom paper face piece 31 is inserted to a predetermined insertion depth into the resin-filled section 51. At this time, the outer peripheral end 31a of the bottom paper face piece 31 is positioned in the axial direction at approximately the center in the thickness direction of the resin-filled section 51, and is positioned so that the distance from the gate section 54 is the same as the predetermined distance D3 shown in Figure 4.

[0046] Although not shown in the figure, each end of the paper-made side panel 32 (bottom end 32c, one side end 32a, the other side end 32b, and top end 32d) is also inserted to a predetermined insertion depth into the resin-filled portion 51. At this time, the constant width region A of the bottom rib 21 N In the area corresponding to this, the outer peripheral edge 31a of the bottom paper face piece 31 and the bottom edge 32c of the side paper face piece 32 are positioned so that they are spaced apart by the specified distance D1 as shown in Figure 4. Similarly, within the resin-filled section 51, one side edge 32a and the other side edge 32b of the side paper face piece 32 are positioned so that they are spaced apart by the specified distance D2 as shown in Figure 4, and the top edge 32d of the side paper face piece 32 is also positioned so that it has a specified insertion depth.

[0047] After each paper face piece (31, 32) is placed in a predetermined position relative to the mold 50, molten resin material is injected from the injection molding machine. The resin material passes through the runner section 53 and flows into the resin-filled section 51 from the gate section 54, as shown by the arrows in FIG. 6(b). The resin material that flows into the resin-filled section 51 flows toward the area for molding the bottom rib 21 and the area for molding the side rib 22, and then toward the area for molding the reinforcing rib 24 and the area for molding the top rib 23. During this process, the resin material flows around both sides of each end section (31a, 32a-32d) of the paper face pieces (31, 32), filling each area within the resin-filled section 51. As a result, both sides of each end section (31a, 32a-32d) of each paper face piece (31, 32) are covered with the resin material, and the joining rib 20 is molded into a predetermined shape. Then, the molded product is removed from the mold 50, and the gate portion 54 is cut off, whereby both surfaces of each end portion (31a, 32a to 32d) of each paper face piece (31, 32) are covered with the joining rib 20 and joined to the joining rib 20, thereby obtaining the composite container 100 having the storage portion 10 having a bottomed cylindrical shape. Note that when the gate portion 54 is cut off, the gate mark 40 is formed in the widened region A of the bottom annular frame 21a of the bottom rib 21. W remains.

[0048] Here, the above-mentioned predetermined width Wn and each predetermined distance D1, D2, D3, and D4 can be appropriately set based on the size of the composite container 100, the strength required for the storage section 10, the type and thickness of the paper face pieces (31, 32), the type and physical properties such as viscosity of the resin material constituting the joining rib 20, etc.

[0049] For example, the predetermined distance D1 is required to be a distance between the outer peripheral edge 31a of the bottom paper panel 31 and the bottom edge 32c of the side paper panel 32 that can bond them with sufficient bonding strength and ensure a sufficient amount of resin to completely cover both end faces with resin material. The same applies to the predetermined width Wn and the predetermined distance D2. In this case, even if the two can be bonded sufficiently, in theory, if it is difficult to get enough resin material to flow between the outer peripheral edge 31a of the bottom paper panel 31 and the bottom edge 32c of the side paper panel 32 in the mold 50, the composite container 100 cannot be manufactured with a good yield. Therefore, the widened region A W It is preferable to take these points into consideration and set the width of the recess 31b and the recess depth of the recess 31b to appropriate sizes.

[0050] On the other hand, it is preferable to set the predetermined distance D3 to a distance that prevents each end (31a, 32c) inserted into the resin filling section 51 from being bent due to the influence of the filling pressure when the resin material is poured into the resin filling section 51 from the gate section 54. The separation distance D4 is preferably set to, for example, the predetermined distance D3 or more, but may be set to an appropriate value, being less than the predetermined distance D3 as described above.

[0051] Here, a polyolefin resin such as polypropylene or polyethylene terephthalate resin is used as the filling resin material to be filled into the mold 50, and a laminated paper having a polyolefin resin sheet such as a polyethylene layer or a polyethylene terephthalate resin sheet or the like laminated on at least the surface that is to be joined to the joining rib 20 is used as the bottom paper face piece 31 and the side paper face pieces 32, so that the joining rib 20 and each paper face piece (31, 32) are thermally fused together during molding, and the joining rib 20 and each paper face piece (31, 32) can be joined well without using adhesives or the like.

[0052] According to the composite container 100 described above, the bottom surface 11 and most of the side surfaces 12 of the storage section 10 are made up of paper panels (31, 32), and the outer peripheral edge 31a of the bottom paper panel 31 and the bottom edge 32c of the bottom paper panel 31, and one side edge 32a and the other side edge 32b of the side paper panel 32 are joined by a resin bottom rib 21 or a resin side rib 22, respectively, to form a bottomed tubular shape. Therefore, compared to when the entire storage section 10 is made up of resin, the composite container 100 can significantly reduce the amount of resin used, while the joining rib 20 allows the strength required of the storage section 10 to be maintained.

[0053] In this embodiment, each end (31a, 32a-32d) of each paper face piece (31, 32) cut to a predetermined shape is joined with a joining rib 20. If moisture or the like adheres to the cut end surface, moisture may penetrate into the interior of each paper face piece (31, 32), reducing the rigidity of each paper face piece (31, 32). If the paper face piece is made of laminated paper, the laminated sheets may peel off from the surface. However, as in the above embodiment, by joining each end (31a, 32a-32d) of the paper face pieces (31, 32) so that both sides are covered with the joining rib 20, it is possible to prevent moisture from penetrating into the interior of the paper face pieces (31, 32) through each end (31a, 32a-32d). Therefore, the composite container 100 can also be suitably used as a container for storing moist contents such as food or liquid. Furthermore, since the joining rib 20 is joined so as to cover each end (31a, 32a-32d) of each paper face piece (31, 32) from both sides, the joining strength between the joining rib 20 and each paper face piece (31, 32) can be ensured satisfactorily.

[0054] Furthermore, the composite container 100 can be manufactured by applying the insert molding method as described above. That is, the bottom paper face piece 31 and the side paper face pieces 32, which have been cut to a predetermined shape, are placed in predetermined positions as inserts in the mold 50 for manufacturing the joining rib 20, and resin is filled into the resin filling section 51 of the mold 50 from the gate section 54, thereby manufacturing the composite container 100 having the storage section 10 in which the resin joining rib 20 and the paper face pieces (31, 32) are joined together and integrated.

[0055] 7(a), (b) and 8 show a comparative composite container 200 for comparison with the composite container 100 of the above embodiment. In the composite container 200, the bottom paper panel 201 does not have the recess 31b, and the bottom rib 202 is formed in the widened region A. W 8 indicates a gate mark, and symbol 201b in FIG. 8 indicates a side annular frame, which has the same structure and function as the side annular frame 21b of the composite container 100 of the above embodiment, and symbol 201c indicates a connecting portion, which has the same structure and function as the connecting portion 21c of the composite container 100 of the above embodiment. In the composite container 200 of the comparative example, the same reference numerals as those in the composite container 100 of the above embodiment indicate the same structure, and therefore their description will be omitted here. Also, in FIGS. 7(a) and 7(b), only some of the reference numerals are shown. Also, symbol 203 in FIGS. 7(b) and 8 indicates a gate mark, symbol 201b in FIG. 8 indicates a side annular frame, which has the same structure and function as the side annular frame 21b of the composite container 100 of the above embodiment, and symbol 201c indicates a connecting portion, which has the same structure and function as the connecting portion 21c of the composite container 100 of the above embodiment.

[0056] In the composite container 200 of this comparative example, as shown in FIG. 7(b) and FIG. 8, the bottom rib 202 is formed in the widened region A W Therefore, the bottom annular frame 202a of the bottom rib 202 does not have the constant width region A N Also, the gate portion 213 (see FIG. 9) of the mold 210 is provided only in this constant width region A N Since gate marks remain on injection molded products, the gate is generally located in a place on the molded product where it is difficult to see, and the gate is generally located on the bottom side of the container.

[0057] In the composite container 200 of this comparative example, as shown in Figure 8(b), the outer peripheral edge 201a of the bottom paper panel 201 is located axially below the gate mark 203 in the bottom rib 202. Therefore, when a mold 210 shown in Figure 9(a) is used and resin material is filled into the resin filling section 211 from an injection molding machine via the runner section 212 and gate section 213 in the same manner as in the above embodiment, the filling pressure is directly applied to the outer peripheral edge 201a of the bottom paper panel 201. Therefore, as shown in Figure 9(b), there is a risk that the outer peripheral edge 201a of the bottom paper panel 201 will bend.

[0058] On the other hand, as in the composite container 100 of the above embodiment, the bottom rib 21 has the widened region A W and a recess 31b is provided in the bottom paper surface 31, and the widened region A of the mold 50 W If the position corresponding to this is the gate portion 54, then the constant width region A N This makes it easy to ensure the gate diameter of the gate portion 54 while narrowing the width to reduce the amount of resin used, etc. Furthermore, when designing the composite container 100 (and the mold 50), it also becomes easy to position the ends (31a, 32a-32d) of the paper face pieces (31, 32) so that they are not positioned axially below the gate portion 54. This makes it easy to design the gate diameter to achieve a flow rate and volume that will allow the resin material to be injected satisfactorily throughout the resin-filled portion 51. Furthermore, by positioning the ends (31a (32a, 32b)) of the paper face pieces (31, 32) to be joined at least the predetermined distance D3 from the gate portion 54, it is possible to prevent the filling pressure of the resin material from being directly applied to these ends, thereby preventing problems such as bending of these ends during molding. Therefore, according to the manufacturing method of the composite container of the present invention, the composite container made of different materials, in which a paper face piece (31, 32) and a joining rib 20 are joined, can be manufactured with a high yield using a method similar to a conventional injection molding method (insert molding method).

[0059] As described above, according to the composite container 100 and the manufacturing method of the composite container 100 of the above embodiment, the storage section 10 can be constructed by combining a resin joining rib 20 with a paper storage section 10, while reducing the amount of resin and improving manufacturing efficiency, and the functions required of the storage section 10 can be well maintained.

[0060] The composite container 100 and the method for manufacturing the composite container 100 in the above embodiment are merely one aspect of the composite container and the method for manufacturing the composite container according to the present invention, and the present invention is not limited to the above embodiment, and can be modified as appropriate within the scope that does not deviate from the spirit of the present invention.

[0061] For example, in the above embodiment, the bottom paper sheet 31 has a recess 31b at the outer peripheral edge 31a, and the bottom annular frame 21a of the bottom rib 21 has an enlarged area A W However, in the composite container according to the present invention, the one end and the other end to be joined are joined with a predetermined distance D1 apart from each other in the constant width region A. N And this steady width region A N Widened area A, which is wider than W Therefore, it is sufficient that at least one of the end portions to be joined has a recessed portion recessed inward on the surface. Therefore, in the composite container 100 of the above embodiment, for example, the widened region A is provided on the side annular frame 21b instead of the bottom annular frame 21a. W may be provided.

[0062] In addition, instead of the bottom rib 21, the side rib 22 is provided with the widened region A W In this case, for example, a constant width region A may be provided in which one side end portion 32a and the other side end portion 32b are joined together with a predetermined distance D1 therebetween. N A part of it is the constant width region A N Widened area A, which is wider than W A recess is provided in at least one of the side end portion 32a and the other side end portion 32b, and the widened region A W As described above, when the composite container 100 is manufactured, the widened region A WIf the gate is located at the position corresponding to the constant width region A, a sufficient gate diameter is ensured. N It is preferable to narrow the width of the gate 54 so that the amount of resin used can be reduced. Depending on the use mode of the composite container 100, it may be preferable to arrange the gate 54 on the side surface 12 (for example, the back surface) rather than on the bottom surface 11. Therefore, depending on the use mode and shape of the composite container 100, the recess 31b provided in the paper face pieces (31, 32) and the widened region A of the joining rib 20 may be W The position of is not particularly limited.

[0063] Furthermore, in the above embodiment, the joining ribs 20 (bottom ribs 21, side ribs 22, top ribs 23) excluding the reinforcing ribs 24 are joined to the respective ends (outer peripheral end 31a, bottom end 32c, one side end 32a, the other side end 32b, top end 32d) so as to cover both sides of each paper face piece (bottom paper face piece 31, side paper face piece 32), and these joining ribs 20 protrude from the inner and outer sides of the storage section 10. However, depending on the contents of the composite container 100 and the mode of use, for example, each end may be bent from the inner side or the outer side of the storage section 10 so that the joining ribs 20 protrude only from the inner side or the outer side of the storage section 10.

[0064] For example, when the contents are liquid or food containing a large amount of water, it may be preferable that these joining ribs 20 do not protrude from the inner surface of the storage section 10. Furthermore, when the composite container 100 is used as a container for use in a bathroom, etc., water droplets may adhere to the outer surface of the composite container 100 due to condensation, etc., and it may be preferable that the joining ribs 20 do not protrude from the outer surface of the storage section 10. As described above, the manner in which the joining ribs 20 are provided can be determined arbitrarily depending on the contents and usage of the composite container 100. It is sufficient that the ends (31a, 32c, etc.) of each paper face piece (31, 32) are covered from both sides by the joining ribs 20, and that, when the ends (31a, 32c, etc.) of each paper face piece (31, 32) have cut end surfaces, the entire cut end surfaces are covered by the joining ribs 20. Note that the joining ribs 20 referred to in the present invention mainly refer to the bottom ribs 21 or the side ribs 22, and the top ribs 23 and the reinforcing ribs 24 are optional components in the present invention.

[0065] In the above embodiment, side ribs 22 and reinforcing ribs 24 are provided on the side surface 12 of the storage section 10, but the number of reinforcing ribs 24 constituting the side ribs 22 can be increased or decreased depending on the strength (rigidity) required for the storage section 10. When the strength required for the storage section 10 is ensured by the side ribs 22, etc., there is no need to provide the reinforcing ribs 24.

[0066] In the above embodiment, an example has been shown in which 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.

[0067] In the above embodiment, the side surface 12 of the storage unit 10 is formed by rolling one paper side panel 32 and joining one side end 32a and the other side end 32b with the side rib 22, but the number of paper side panels 32 used to form the side surface 12 of the storage unit 10 is not particularly limited. For example, two or more paper side panels 32 may be used and the ends of each paper side panel 32 may be joined together to form a cylindrical shape. Furthermore, one paper side panel 32 may have a cut portion, and the cut edges may be joined together using a part of the side rib 22 as in the above embodiment. In this way, storage units 10 of various shapes can be formed. [Explanation of symbols]

[0068] 10: Storage section 11: Bottom 12: Side 13: Top 20: Joint rib 21: Bottom rib 21a: Bottom ring frame 21b: Side ring frame 21c: Continuous part 22: Side rib 23: Top rib 23a: Inner frame 23b: Flange part 23c: Outer frame 23d: Inner rib 23e: Peripheral rib 23f: Circular convex rib 24: Reinforcing rib 31: Paper bottom faceplate 31a: Outer edge 31b: recess 32: Paper faceplate 32a: Side end 32b: Side edge 32c: Bottom end 32d: Top end 40: Gate marks 50: Mold 51: Resin filling section 52: Holding part 53: Runner Club 54: Gate section 100: Composite container 200: Composite container 201: Paper bottom faceplate 201a: Outer edge 202: Bottom rib 202a: Bottom ring frame 210: Mold 211: Resin filling section 213: Gate section A N :Constant width region A W : Widening area O: Center axis line

Claims

1. A composite container having a storage section formed by joining one end and the other end of a paper face piece with a resin joining rib, At least one of the one end and the other end is provided with a recess recessed inward of a surface, The joining rib has a constant width region having a predetermined width and joining the one end and the other end so that both surfaces are covered with a state in which the one end and the other end are separated by a predetermined distance D1 in a portion other than the recess, and a widened width region that covers both surfaces of the recess and is widened from the predetermined width in accordance with the recess amount of the recess, The joining rib has a top surface rib that forms an outer edge of the top surface of the storage section, The top surface rib has an inner frame body joined to the top end of the side paper surface body that constitutes the side surface of the storage section, a flange portion that protrudes outward at the upper end of the inner frame body, and an outer frame body that hangs down from the outer edge of the flange portion, The composite container has an inner peripheral rib provided along the inner peripheral surface of the outer frame at a lower end of the inner peripheral surface.

2. A peripheral rib is provided at a lower end of the outer peripheral surface of the outer frame so as to protrude radially outward. The composite container according to claim 1.

3. The one end is an outer peripheral end of a bottom paper surface body that constitutes the bottom surface of the storage section, The other end is a bottom end of a paper side surface that constitutes a side surface of the storage section, The recess is provided on the outer peripheral edge of the bottom paper face piece or the bottom edge of the side paper face piece, 2. The composite container according to claim 1, wherein the joining rib is a bottom rib that joins the outer peripheral edge of the bottom paper panel and the bottom end of the side paper panel to form the outer edge of the bottom surface.

4. The side surface of the storage section has a side rib that joins one side end and the other side end of one or more of the side paper face bodies from both sides, with the one side end and the other side end being spaced apart by a predetermined distance D2, 4. The composite container according to claim 3, wherein the side ribs and the bottom rib are joined at the widened region.

5. 5. The composite container according to claim 3, wherein the joining rib is an injection-molded member formed by injecting a resin material from a position corresponding to the widened region.

6. A method for manufacturing a composite container having a storage section formed by joining one end and the other end of a paper face piece with a resin joining rib, a recessed portion recessed inwardly of a surface of at least one of the one end portion and the other end portion; The joining rib has a predetermined width and includes a constant width region that joins the one end and the other end so as to cover both surfaces of the one end and the other end in a state where the two ends are spaced apart by a predetermined distance D1 in a portion other than the recess, and an expanded width region that covers both surfaces of the recess and is expanded from the predetermined width in accordance with the recess amount of the recess, The joining rib has a top surface rib that forms an outer edge of the top surface of the storage section, The top surface rib has an inner frame body joined to the top end of the side paper surface body that constitutes the side surface of the storage section, a flange portion that protrudes outward at the upper end of the inner frame body, and an outer frame body that hangs down from the outer edge of the flange portion, an inner peripheral rib is provided along a lower end of an inner peripheral surface of the outer frame body, A mold is used to form a resin filling portion having a shape corresponding to the joining rib, A method for manufacturing a composite container, in which the paper face piece is placed at a predetermined position in the mold with the one end and the other end spaced a predetermined distance D1 apart, a position corresponding to the widened region of the resin filling section is designated as a gate section, and resin material is filled into the resin filling section from the gate section.

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