An assembled paper container, a method of manufacturing an assembled paper container, and a manufacturing apparatus for an assembled paper container

Abstract

Provided is an assembled paper container capable of inhibiting leakage of contents from a storage portion of a container body or seepage of contents. An assembled paper container (1) has a container body (11) having a storage portion (12), and a resin film (3) covering an inner surface of the container body (11), characterized in that the container body (11) has a bottom surface (121), a plurality of side surfaces (122), and a flange portion (13), a step (22) extending from the storage portion (12) side toward the outside is provided on an upper surface (131) of the flange portion (13), the step (22) is produced by a first fold-back piece (13a) and a second fold-back piece (13b) being adhered to each other in a superimposed manner after assembly, and the resin film (3) has a protruding portion (31) that crosses the step (22) above the step (22) in a portion covering the upper surface (131) of the flange portion (13) of the container body (11).

Description

TECHNICAL FIELD

[0001] The present application relates to an assembled paper container, a manufacturing method of the assembled paper container, and a manufacturing apparatus of the assembled paper container. BACKGROUND

[0002] In the past, an assembled paper container has been known in which a tray-shaped container main body having a flange portion at an upper end is assembled from a blank sheet of which a main raw material is paper. In this assembled paper container, a film of a thermoplastic resin having a resin property is sometimes pasted on an inner surface of the container main body including an upper surface of the flange portion (see Patent Documents 1, 2, etc.). This assembled paper container with the film of the thermoplastic resin has a resin property, and thus is mainly used as a tray or a bowl for storing food, etc.

[0003] Further, compared with a plastic container, the assembled paper container is a product that can consider the environment, for example, by suppressing the generation of secondary microplastics generated in the environment, etc. Moreover, it is also possible to peel the film of the thermoplastic resin from the container main body, to perform classification of the film of the thermoplastic resin and the container main body made of paper, and to perform recycling of each of the film of the thermoplastic resin and the container main body. In view of these advantages, it is also expected to apply, for example, MAP (Modified Atmosphere Packaging) to the assembled paper container to be used as a packaging container for food, etc. and a storage container for food, etc.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. H6-293334

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2019-172339 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] Regarding the container main body of such a conventional assembled paper container, in terms of molding, a gap generated by the end surfaces of the blank sheet approaching each other is formed on the upper surface of the flange portion. The current situation is that even if the inner surface of the container main body including the upper surface of the flange portion is covered with the film of the thermoplastic resin, it is difficult to completely fill the gap. Moreover, the film of the thermoplastic resin is thin, and in the case where the film of the thermoplastic resin is covered on the inner surface of the container main body including the upper surface of the flange portion by, for example, vacuum pressure, the film of the thermoplastic resin is attracted into the gap, and thus it is difficult to plug the gap with only the film of the thermoplastic resin.

[0010] Further, a packaging method (for example, MAP) is developed in which air in the accommodation portion of the container body is replaced with food gas suitable for food and the food is packaged. In the case where such a packaging method is applied to the assembled paper container with the resin film, the top seal is attached to the resin film on the upper surface of the flange portion. However, since the top seal is also thin, even if the top seal is attached to the resin film, a cavity along the gap is formed between the upper surface of the resin film and the lower surface of the top seal. That is, even with the top seal, it is difficult to completely block the cavity. Moreover, both ends of the cavity are open. Therefore, the accommodation portion of the container body communicates with the outside of the container body via the cavity.

[0011] According to the above, in the assembled paper container with the resin film, even if the accommodation portion is covered with the top seal, there is a possibility that the leakage of the accommodated object or the exudation of the accommodated object from the accommodation portion via the cavity.

[0012] Therefore, the present application is proposed in view of the above-described problems, and aims to provide an assembled paper container capable of inhibiting the leakage of an accommodated object from an accommodation portion of a container body or the exudation of an accommodated object, a manufacturing method of the assembled paper container, and a manufacturing apparatus of the assembled paper container.

[0013] Means for solving the problem

[0014] The assembled paper container of the first aspect has a container body assembled from a blank in which a paper is a main material, and the container body has an accommodation portion, and a resin film covering an inner surface of the container body, characterized in that the container body has a bottom surface, a plurality of side surfaces rising from the bottom surface, and a flange portion continuous with upper end portions of the plurality of side surfaces and extending toward an outside of the accommodation portion after assembly, and a step extending toward the outside from the accommodation portion side is provided on an upper surface of the flange portion, the step being generated by the first return sheet and the second return sheet of the blank after assembly being attached to each other in a superimposed manner, and the resin film has a protruding portion across the step above the step in a portion covering the upper surface of the flange portion of the container body.

[0015] The assembled paper container of the second aspect is based on the first aspect, and characterized in that the container body is assembled from one blank.

[0016] The assembled paper container of the third aspect is based on the first or second aspect, and characterized in that the protruding portion of the resin film has a cross-sectional shape having at least one corner portion or a circular arc portion across the step above the step.

[0017] The assembled paper container of the fourth aspect is based on any of the first to third aspects, and is characterized in that the assembled paper container further has a top seal adhered to the resin film covering the upper surface of the flange portion, covering the storage portion, the top seal being adhered to the resin film above the upper surface of the flange portion, flattening the protruding portion and adhering to the resin film across the step.

[0018] The assembled paper container of the fifth aspect is based on the fourth aspect, and is characterized in that the resin film is folded into three or more layers including the peripheral portion of the protruding portion being flattened by the top seal.

[0019] The manufacturing method of the assembled paper container of the sixth aspect is a manufacturing method of an assembled paper container having a container body assembled from a blank mainly made of paper, the container body having a storage portion, and a resin film covering an inner surface of the container body, and is characterized by comprising: a box-making step of forming the storage portion of the container body by standing a plurality of side surfaces from a bottom surface of the blank, folding back upper portions of the plurality of side surfaces, and adhering a first folded-back piece and a second folded-back piece of the blank to each other in a superimposed manner, thereby assembling the container body to have a step extending outward from the storage portion on an upper surface thereof and a flange portion extending outward toward the storage portion; and a protruding portion forming and resin film covering step of disposing the resin film to the inner surface of the container body assembled by the box-making step, attracting a surface of a protruding portion forming region of the resin film across the step, forming a protruding portion across the step above the step of the resin film, and extracting air between the container body and the resin film from a gap around both the container body and the resin film, thereby covering the resin film to the inner surface of the container body.

[0020] The manufacturing method of the assembled paper container of the seventh aspect is based on the sixth aspect, and is characterized in that, in the protruding portion forming and resin film covering step, an attracting start timing of attracting the surface of the protruding portion forming region of the resin film across the step is earlier than an extraction start timing of extracting the air between the container body and the resin film.

[0021] The manufacturing method of the assembled paper container of the eighth aspect is based on the sixth or seventh aspect, and is characterized in that the manufacturing method of the assembled paper container further comprises a top seal adhering step of adhering a top seal to the resin film covering the upper surface of the flange portion after the protruding portion forming and resin film covering step, such that the top seal flattens the protruding portion above the upper surface of the flange portion and adheres to the resin film across the step.

[0022] In the manufacturing apparatus for an assembled paper container according to the ninth embodiment, the assembled paper container includes: a container body assembled from paper-based preforms, the container body having a receiving portion; and a resin film covering the inner surface of the container body. The apparatus is characterized by comprising: a lower mold holding the container body; a suction covering portion disposed in the lower mold to suction air between the container body and the resin film, thereby covering the inner surface of the container body with the resin film; and an upper mold. The upper mold is opposite to the lower mold and sandwiches the resin film between them; the upper mold has a flange pressing part that is housed therein and presses the flange of the container body and the resin film on the flange; and the upper mold has a forming part that is disposed on the flange pressing part and attracts the protrusion forming area of ​​the resin film on the flange to form a protrusion that crosses a step on the resin film. The step is formed by the first folding piece and the second folding piece of the blank being attached to each other in an overlapping manner and extends outward from the housing part side.

[0023] The assembly paper container manufacturing apparatus of the tenth embodiment is based on the ninth embodiment, characterized in that the assembly paper container manufacturing apparatus is configured such that in the region where the protrusions of the resin film are formed, the attraction direction of the forming part is opposite to the attraction direction of the attraction covering part, and the attraction force of the forming part is greater than the attraction force of the attraction covering part.

[0024] The assembly paper container manufacturing apparatus of the 11th embodiment is based on the 9th or 10th embodiment, characterized in that the attraction start timing of the forming part is set earlier than the attraction start timing of the attraction covering part.

[0025] Invention Effects

[0026] According to the present invention with the above-described structure, an assembled paper container can be provided that can prevent the contents from leaking out of the storage section of the container body or from seeping out. Attached Figure Description

[0027] Figure 1 (a) is a top view illustrating an assembly paper container according to an embodiment of the present invention. Figure 1 (b) is shown Figure 1 (a) Side view of the assembled paper container. Figure 1 (c) is shown Figure 1 (a) A three-dimensional view of an assembled paper container.

[0028] Figure 2 It is shown Figure 1 The unfolded diagram of the blank used in the assembly of paper containers.

[0029] Figure 3 is an enlarged sectional view of a portion along Figure 1 the arrow of A-A line, and is a schematic sectional view showing an example of the protruding portion.

[0030] Figure 4 is a plan view showing a state in which the receiving portion of the assembled paper container of Figure 1 is covered with a top seal.

[0031] Figure 5 (a) of Figure 4 is a sectional view of a theoretically assumed flattened protruding portion periphery in the assembled paper container of Figure 5 (b) is a sectional view of an actual flattened protruding portion periphery.

[0032] Figure 6 is a flowchart showing a process of a manufacturing method of the assembled paper container of the embodiment of the present application.

[0033] Figure 7 (a) of Figure 7 and (b) of are schematic sectional views showing an example of a manufacturing apparatus of the assembled paper container of the embodiment of the present application.

[0034] Figure 8 (a) of Figure 8 and (b) of are schematic sectional views showing a situation of forming the protruding portion.

[0035] Figure 9 is a schematic block diagram showing an example of a manufacturing system of the assembled paper container of the embodiment of the present application.

[0036] Figure 10 (a) of Figure 10 is a plan view showing the assembled paper container of the embodiment of the prior application, Figure 10 (b) is a side view of the assembled paper container of Figure 10 (a), Figure 10 (c) is a perspective view of the assembled paper container of (a).

[0037] Figure 11 is a table of comparison results of experimental verification of the assembled paper container of the present application and the assembled paper container of the prior application. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments exemplified by applying the present application will be described with reference to the drawings.

[0039] EMBODIMENT

[0040] As shown in (a) to Figure 1 of the drawings, the assembled paper container of the present application is a container having a receiving portion 1 in which a product is received, and a protruding portion 2 which is provided on the receiving portion 1 and protrudes from the receiving portion 1.Figure 1 As shown in (c), the assembled paper container 1 of the embodiment of the present invention has a container body 11 and a resin film 3 covering the inner surface of the container body 11.

[0041] The container body 11 has a storage portion 12 and a flange portion 13. Furthermore, the container body 11 is... Figure 2 The image shows a blank sheet 2 made primarily of paper, assembled from these materials. Figure 2 In the diagram, dashed lines represent "valley folds," and single-dot dashed lines represent "peak folds." Valley fold lines and peak fold lines are formed, for example, by perforation lines, half-cuts, or grid lines. Furthermore, solid lines within the blank sheet 2 represent "cuts." The container body 11 is constructed by applying "valley folds" and "peak folds" to the blank sheet 2 and by attaching the first folded piece 13a and the second folded piece 13b to each other in a mutually overlapping manner.

[0042] In this embodiment, the storage section 12 has eight side surfaces 122 that rise from the bottom surface 121. Furthermore, the storage section 12 can be constructed as long as there are three or more side surfaces 122.

[0043] The flange portion 13 is continuous with the upper ends of each side 122 and extends outward toward the storage portion 12. At each of the four corners of the upper surface 131 of the flange portion 13, there are two steps 22 extending outward from the storage portion 12 side. These steps 22 are formed by attaching the first folded piece 13a and the second folded piece 13b of the assembled blank 2 in a manner that they overlap each other.

[0044] A resin film 3 covers the inner surface of the container body 11, including the upper surface 131 of the flange portion 13. The portion of the resin film 3 covering the upper surface 131 of the flange portion 13 of the container body 11 has a protrusion 31 that crosses the step 22 above it. In the assembled paper container 1 of this embodiment, there are eight steps 22, and a protrusion 31 is formed for each step 22. Alternatively, multiple protrusions 31 can be provided for each step 22.

[0045] like Figure 3 As shown in one example, the protrusion 31 has a quadrilateral cross-sectional shape with two corners, a first corner 31a and a second corner 31b, at both ends of the upper surface 313 above the step 22. Furthermore, the cross-sectional shape of the protrusion 31 is not limited to such a quadrilateral shape; it can also be implemented in any shape, such as a triangle or a semicircle.

[0046] Furthermore, examples of resins used for the resin film 3, which is suitable for covering the inner surface of the container body 11 and capable of forming the protrusions 31, include thermoplastic resins such as polyethylene (PE), polypropylene (PP), and other polyolefins; polyvinyl chloride; polyethylene terephthalate (PET), and other polyesters; ethylene-vinyl acetate copolymer (EVA); ethylene-acrylic acid copolymer; polyamide; polyvinylidene chloride; polystyrene; polycarbonate; polybutene; and polyvinyl alcohol. The resin film 3 can be a single film of any of the above materials, or a film mixed with multiple of the above materials. Furthermore, the resin film 3 can be a single-layer film or a multi-layered film.

[0047] Next, based on the above method, the assembled paper container 1 using the top seal 4 to cover the storage part 12 will be described.

[0048] like Figure 4 As shown, the assembled paper container 1 can package and store food and other items by covering the storage portion 12 with a top seal 4. The top seal 4 is adhered to a resin film 3 on the upper surface 131 of the flange portion 13. Thus, the top seal 4 covers the storage portion 12. In this embodiment, the top seal 4, above the upper surface 131 of the flange portion 13, crosses the step 22, flattens the protrusion 31, and adheres it to the resin film 3. When the top seal 4 is adhered to the resin film 3, the top seal 4 is pressed by a press while heated in the pressing area 32 shown by the dashed line. In this embodiment, the protrusion 31 is designed so that the entire protrusion 31 converges within the width of the pressing area 32. Thus, the protrusion 31 can be reliably flattened by the press.

[0049] Here, theoretically, the cross-section around the protrusion 31 is envisioned as... Figure 5 As shown in (a), but the actual confirmed result is Figure 5 As shown in (b).

[0050] However, it was confirmed that: even for Figure 5 As shown in (b), the lower surface 41 of the top seal 4 can also be fully heat-pressed onto the upper surface of the resin film 3 above the step 22, so that the top seal 4 can be attached to the upper surface of the resin film 3 in a way that covers the hole 5 created by the step 22.

[0051] Furthermore, it was confirmed that when the protrusion 31 is flattened and folded into a multilayered resin film 3 with three or more layers, it will exert a reaction force on the top seal 4 during pressing, making it easy to heat-press the lower surface 41 of the top seal 4 onto the upper surface of the resin film 3.

[0052] Next, use Figure 6A manufacturing method of the assembled paper container 1 of the embodiment of the present application will be described.

[0053] First, in the manufacturing method of the assembled paper container 1 of the embodiment of the present application, a blank cutting step S1 of forming the above-mentioned blank 2 in a cut-off manner is performed, and the blank 2 is manufactured.

[0054] Next, a box making step S2 is performed, in which the container body 11 is assembled from the blank 2 cut out and manufactured by the blank cutting step S1.

[0055] Next, a protrusion portion forming and resin film covering step S3 is performed, in which, to the inner surface of the container body 11 assembled by the box making step S2, the resin film 3 is arranged, the surface of the protrusion portion forming region of the resin film 3 across the step 22 is sucked, the protrusion portion 31 across the step 22 is formed above the step 22 of the resin film 3, and, while air between the container body 11 and the resin film 3 is drawn from the gap around both the container body 11 and the resin film 3 by, for example, vacuum pressure, the resin film 3 is covered on the inner surface of the container body 11 by pressurizing from the upper portion of the resin film 3. Further, as the method of covering the resin film 3 on the container body 11, vacuum pressure is exemplified, but it is also possible to draw air between the container body 11 and the resin film 3 only by sucking from the gap around both the container body 11 and the resin film 3, or only by pressurizing from the upper portion of the resin film 3.

[0056] At this time, in the protrusion portion forming and resin film covering step, the suction start timing of sucking the surface of the protrusion portion forming region of the resin film 3 across the step 22 is earlier than the drawing start timing of drawing air between the container body 11 and the resin film 3.

[0057] Next, an article storing step S4 is performed, in which an article such as food is stored in the storage portion 12 of the assembled paper container 1 in a state where the top seal 4 is not attached, which is manufactured by the protrusion portion forming and resin film covering step S3.

[0058] Next, a top seal attaching step S5 is performed, in which, using a press machine, the top seal 4 is attached to the resin film 3 covering the upper surface of the flange portion 13 of the assembled paper container 1 in which the article such as food is stored in the storage portion 12 by the article storing step S4, in a manner such that the protrusion portion 31 is flattened above the upper surface of the flange portion 13 and across the step 22.

[0059] Finally, a trimming process S6 is performed in which the excess resin film 3 around the assembled paper container 1 is trimmed away, thereby manufacturing the assembled paper container 1, and the manufacturing method of the assembled paper container 1 of the present embodiment is completed.

[0060] Next, the manufacturing device 600 of the assembled paper container 1 of the present embodiment is described. Figure 7

[0061] As shown in (a) of FIG. 1 and (b) of FIG. 2, the manufacturing device 600 of the assembled paper container 1 of the present embodiment is a new manufacturing device capable of manufacturing the assembled paper container 1 of the present embodiment. The manufacturing device 600 is capable of covering the resin film 3 to the container body 11 of the flange portion 13, and at the time of covering, forming the protrusion portion 31 in the resin film 3. Figure 7 Figure 7 As shown in (a) of FIG. 1 and (b) of FIG. 2, the manufacturing device 600 of the assembled paper container 1 of the present embodiment is a new manufacturing device capable of manufacturing the assembled paper container 1 of the present embodiment. The manufacturing device 600 is capable of covering the resin film 3 to the container body 11 of the flange portion 13, and at the time of covering, forming the protrusion portion 31 in the resin film 3.

[0062] The manufacturing device 600 has a lower mold 610, a suction covering portion 611, an upper mold 620, a flange pressing portion 630, and a molding portion 631.

[0063] The container body 11 is placed on the lower mold 610.

[0064] The suction covering portion 611 is provided to the lower mold 610, and is connected to a vacuum pump 640. The suction covering portion 611 is configured to suck the resin film 3 through the container body 11 placed on the lower mold 610, thereby discharging air from the gap between the container body 11 and the surroundings.

[0065] The upper mold 620 is opposed to the lower mold 610, and is capable of moving up and down. The resin film 3 is sandwiched between the lower mold 610 and the upper mold 620, and when the upper mold 620 and the lower mold 610 are tightly closed with the resin film 3 sandwiched therebetween, a processing space in a substantially airtight state is formed. In this processing space, the resin film 3 is covered to the receiving portion 12 and the flange portion 13 by, for example, vacuum pressure.

[0066] The flange pressing portion 630 is housed in the upper mold 620. The flange pressing portion 630 is supported to the top plate portion 621 of the upper mold 620 by an elastic member 632 such as a spring, which is stretchable and contractible. The flange pressing portion 630 presses the flange portion 13 and the resin film 3 on the flange portion 13, for example, during vacuum pressure.

[0067] ​​A forming part 631 is provided on the flange pressing part 630 and connected to the vacuum pump 640. The forming part 631 attracts the protrusion forming area of ​​the resin film 3 on the flange part 13. The protrusion forming area is set to cross the step 22. The formation of the protrusion 31 is performed, for example, during the process of covering the inner surface of the container body 11 with the resin film 3. The attraction direction of the forming part 631 is opposite to the attraction direction of the attraction covering part 611. In this embodiment, the attraction covering part 611 attracts the resin film 3 in the direction toward the container body 11. The forming part 631 attracts the resin film 3 in the direction away from the container body 11.

[0068] Here, the situation in which the protrusion 31 is formed will be explained.

[0069] like Figure 8 (a) and Figure 8 As shown in (b), when the protrusion 31 is formed by suction, the thickness T of the resin film 3 changes before and after suction. For example, after suction, the thickness T of the resin film 3 of the protrusion 31 becomes thinner. When the thickness T of the resin film 3 of the protrusion 31 becomes thinner, it is easier to fold or flatten the protrusion 31 compared to the case where the thickness T is thicker. This is one of the advantages of forming the protrusion 31 by suction of the resin film 3.

[0070] Here, an example of the operation of the manufacturing apparatus 600 will be explained.

[0071] like Figure 7 (a) and Figure 7 As shown in (b), with the upper mold 620 separated from the lower mold 610, the heated resin film 3 is guided between the upper mold 620 and the lower mold 610.

[0072] Next, the container body 11 is placed in the lower mold 610.

[0073] Next, the upper mold 620 is lowered, and the upper mold 620 is used to press the resin film 3. Furthermore, the flange pressing part 630 is used to press the flange part 13 and the resin film 3 on the flange part 13.

[0074] Next, the resin film 3 is attracted by the suction covering part 611 and the forming part 631 respectively. As a result, the resin film 3 covers the bottom surface 121 of the receiving part 12, the side surface 122 of the receiving part 12, and the upper surface 131 of the flange part 13 respectively. Moreover, on the flange part 13, a protrusion 31 protruding relative to the flange part 13 is formed above the step 22.

[0075] Furthermore, the suction start time of the molding section 631 can be set earlier than the suction start time of the suction covering section 611. When the suction start times are staggered in this way, the protrusion 31 can be formed before the resin film 3 covers the upper surface 131 of the flange section 13. Therefore, the advantage of easy forming of the protrusion 31 can be obtained.

[0076] Furthermore, the attraction direction of the forming part 631 can be set to be opposite to the attraction direction of the covering part 611, and the attraction force of the forming part 631 is greater than that of the covering part 611. When the attraction forces are made to be different in this way, the protrusion forming area is easily attracted outward, thus achieving the advantage of easy formation of the protrusion 31.

[0077] Then, the upper mold 620 is raised, causing the assembled paper container 1 to detach from the manufacturing device 600.

[0078] After the final trimming to remove excess resin film 3 around the assembled paper container 1, the assembled paper container 1 is complete.

[0079] Thus, the assembly paper container 1 manufacturing apparatus 600 according to this embodiment can manufacture the assembly paper container 1.

[0080] Next, use Figure 9 The manufacturing system 700 of the assembled paper container 1 according to an embodiment of the present invention will be described.

[0081] The assembly paper container 1 manufacturing system 700 of the present invention uses a take-up roller 720 to take up the resin film 3 wound on the feed roller 710, and covers the container body 11 with flange portion 13 with the resin film 3.

[0082] like Figure 9 As shown, the manufacturing system 700 includes a feed roller 710, a take-up roller 720, a heater 730, a manufacturing apparatus 600, and a shearing machine 740.

[0083] A roll of resin film 3 is mounted on the feed roller 710.

[0084] One end of the strip-shaped resin film 3 is mounted on the take-up roller 720, which takes up the strip-shaped resin film 3. The strip-shaped resin film 3 moves forward from the feed roller 710 toward the take-up roller 720 along the feed direction W.

[0085] The heating unit 730 is positioned between the feed roller 710 and the take-up roller 720 to heat the strip-shaped resin film 3.

[0086] As described above, the manufacturing apparatus 600 is disposed between the heating machine 730 and the winding roller 720.

[0087] The cutting machine 740 is arranged between the manufacturing device 600 and the winding roller 720, and cuts the assembled paper container 1 manufactured by the manufacturing device 600. Thereby, the assembled paper container 1 is separated from the resin film 3 in the form of a tape.

[0088] Thus, the manufacturing system 700 of the assembled paper container 1 of the present embodiment has the manufacturing device 600. Therefore, according to the manufacturing system 700, it is possible to manufacture the assembled paper container 1. Moreover, according to the manufacturing system 700, it is possible to continuously manufacture the assembled paper container 1 from the resin film 3 in the form of a tape.

[0089] According to the above-described embodiment of the present application, it is possible to heat-press the top seal 4 to the upper surface of the resin film 3 above the step 22, and to cover the top seal 4 to the upper surface of the resin film 3 above the step 22 in a manner to cover the hollow 5 generated by the step 22.

[0090] Moreover, as a result of the protruding portion 31 being flattened, the side wall of the protruding portion 31 of the resin film 3 is folded and stacked in multiple layers, and it is easy to heat-press the top seal 4 to the upper surface of the resin film 3 even above the step 22.

[0091] Thus, according to the present embodiment, it is possible to provide the assembled paper container 1 that can suppress the leakage of the contents from the storage portion 12 of the container body 11 or the seepage of the contents using the resin film 3 and the top seal 4. Example

[0092] Hereinafter, the results of the experimental verification performed in order to confirm the effects of the present application will be described.

[0093] In this experimental verification, for the assembled paper container 1 of the present application and the assembled paper container 100 of the prior application (Japanese Patent Application No. 2019-235300) of the present applicant, a plurality of conditions were changed, the top seal 4 was attached, the leakage confirmation inspection of the contents inside was performed, and they were compared.

[0094] Here, as in (a) to Figure 10 of FIG. 10, the results of the leakage confirmation inspection of the contents inside are shown in Table 1. Figure 10As shown in (c), the prior art assembled paper container 100 has a container body 11 assembled from a blank mainly made of paper, the container body 11 having a storage portion 12, and a resin film 3 covering the inner surface of the storage portion 12, wherein the assembled paper container 100 is configured such that the container body 11 has a bottom surface 121, a plurality of side surfaces 122 rising from the bottom surface 121, and a flange portion 13 connected to the plurality of side surfaces 122, the upper surfaces of the flange portion 13 after assembly become the same surface, and the gap 220 generated by the end surfaces of the blank approaching each other on the upper surface of the flange portion 13 extends from the storage portion 12 toward the outside of the container body 11, and the resin film 3 covers the upper surface of the flange portion 13, and the protrusion portion 31 across the gap 220 is provided above the gap 220.

[0095] As conditions for comparing the assembled paper container 1 of the present application with the prior art assembled paper container 100, the cross-sectional shape of the protrusion portion 31 was set to five types of quadrangular shape, trapezoidal shape, triangular shape, M-shaped shape, and semicircular shape. Also, regarding the width of the protrusion portion 31, in the case of the quadrangular shape, it was set to 2 mm, in the case of the trapezoidal shape, it was set to 2 mm and 3 mm, in the case of the triangular shape, it was set to 2 mm, in the case of the M-shaped shape, it was set to 2 mm, and in the case of the semicircular shape, it was set to 2 mm. Also, the height of the protrusion portion 31 was set to 1 mm and 2 mm.

[0096] As a result, as shown in Figure 11 , it was confirmed that the assembled paper container 1 of the present application did not leak under any conditions.

[0097] On the other hand, regarding the prior art assembled paper container 100, as shown in Figure 11 , the assembled paper container 100 having the cross-sectional shape of the protrusion portion 31 set to quadrangular shape, width of 1 mm, and height of 1 mm, and the assembled paper container 100 having the cross-sectional shape of the protrusion portion 31 set to semicircular shape, width of 2 mm, and height of 2 mm leaked.

[0098] From this, it was found that the assembled paper container 1 of the present application has an advantage over the prior art assembled paper container 100.

[0099] Also, five samples of the assembled paper container 1 of the present application were prepared in which the cross-sectional shape of the protrusion portion 31 was set to quadrangular shape, the width of the protrusion portion 31 was set to 2 mm, and the height of the protrusion portion 31 was set to 2 mm, the protrusion portion 31 being provided at a position deviated from the pressing region 32 of the top seal 4, and the same leakage confirmation test was performed.

[0100] As a result, three out of the five samples leaked.

[0101] Therefore, as to the assembled paper container 1 of the present application, the position where the protrusion 31 is provided is preferably converged in the pressing area 32 of the top seal 4, as in the assembled paper container 100 of the prior art.

[0102] The above-described embodiments are illustrative and do not restrict the scope of the application. These new embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made thereto without departing from the scope and spirit of the application. These embodiments and modifications thereof are included within the scope and spirit of the application, and are included within the scope of the present application and the equivalent thereof recited in the claims.

[0103] Explanation of Reference Numerals

[0104] 1: assembled paper container; 11: container body; 12: storage portion; 121: bottom surface; 122: side surface; 13: flange portion; 131: upper surface; 13a: first return piece; 13b: second return piece; 2: blank; 22: step; 3: resin film; 31: protrusion; 31a: first corner portion; 31b: second corner portion; 313: upper surface; 32: pressing area; 4: top seal; 41: lower surface; 5: hollow; 600: manufacturing device; 610: lower mold; 611: suction cover portion; 620: upper mold; 621: top plate portion; 630: flange pressing portion; 631: molding portion; 632: elastic member; 640: vacuum pump; 700: manufacturing system; 710: feed roller; 720: take-up roller; 730: heating machine; 740: cutting machine; S1: blank cutting process; S2: box making process; S3: protrusion forming and resin film covering process; S4: storage storage process; S5: top seal pasting process; S6: cutting process; T: thickness; W: feed direction.

Claims

1. An assembled paper container having: a container body assembled from a blank of a paper-based material, the container body having a storage portion; and a resin film covering an inner surface of the container body, characterized in that the container body has: a bottom surface; a plurality of side surfaces rising from the bottom surface; and a flange portion continuous with upper end portions of the plurality of side surfaces and extending toward an outer side of the storage portion after assembly, a step extending toward an outer side from the storage portion side is provided on an upper surface of the flange portion, the step being generated by the first and second return pieces of the blank being adhered to each other in a superimposed manner after assembly, and the resin film has a protruding portion across the step above the step on a portion covering the upper surface of the flange portion of the container body.

2. The assembled paper container according to claim 1, characterized in that the container body is assembled from one blank.

3. The assembled paper container according to claim 1 or 2, characterized in that the protruding portion of the resin film has a cross-sectional shape having at least one corner portion or a circular-arc portion across the step above the step.

4. The assembled paper container according to claim 1 or 2, characterized in that the assembled paper container further has a top seal adhered to the resin film covering the upper surface of the flange portion, covering the storage portion, the top seal being adhered to the resin film across the step, flattening the protruding portion above the upper surface of the flange portion.

5. The assembled paper container according to claim 4, characterized in that the resin film is folded into three or more layers including a peripheral portion of the protruding portion, the protruding portion being flattened by the top seal.

6. A manufacturing method of an assembled paper container having: a container body assembled from a blank of a paper-based material, the container body having a storage portion; and a resin film covering an inner surface of the container body, characterized in that the manufacturing method of the assembled paper container has the following steps: a box-making step of forming the storage portion of the container body by rising a plurality of side surfaces from a bottom surface of the blank, returning upper portions of the plurality of side surfaces, and adhering a first return piece and a second return piece of the blank to each other in a superimposed manner, thereby assembling the container body, the container body having a flange portion extending toward an outer side of the storage portion and having a step extending toward an outer side from the storage portion on an upper surface thereof; and ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The protrusion forming and resin film covering step is performed by arranging the resin film on the inner surface of the container body assembled by the box making step, sucking the surface of the protrusion forming region of the resin film that crosses the step, forming a protrusion that crosses the step on the resin film on the step, and extracting air between the container body and the resin film from the gap around the container body and the resin film, and covering the resin film on the inner surface of the container body.

7. The method of manufacturing an assembled paper container according to claim 6, wherein In the protrusion forming and resin film covering step, the sucking start timing of the surface of the protrusion forming region of the resin film that crosses the step is earlier than the extraction start timing of the air between the container body and the resin film.

8. The method of manufacturing an assembled paper container according to claim 6 or 7, wherein The method of manufacturing an assembled paper container further has a top seal pasting step of pasting a top seal to the resin film covering the upper surface of the flange portion in such a manner that the top seal flattens the protrusion on the upper surface of the flange portion and crosses the step after the protrusion forming and resin film covering step.

9. A manufacturing apparatus of an assembled paper container having a container body assembled from a blank of a paper-based material, the container body having a storage portion, and a resin film covering an inner surface of the container body, characterized by The manufacturing apparatus of an assembled paper container has a lower mold on which the container body is placed, a suction covering portion provided to the lower mold, which sucks air between the container body and the resin film to cover the resin film on the inner surface of the container body, an upper mold opposed to the lower mold, which sandwiches the resin film between the lower mold, a flange pressing portion housed in the upper mold, which presses a flange portion of the container body and the resin film on the flange portion, and a molding portion provided to the flange pressing portion, which sucks a protrusion forming region of the resin film on the flange portion to form a protrusion that crosses a step on the resin film, the step being generated by the first and second return pieces of the blank being adhered to each other in a superimposed manner and extending from the storage portion side to the outside.

10. The manufacturing apparatus of an assembled paper container according to claim 9, wherein the manufacturing apparatus of an assembled paper container is configured so that the suction direction of the molding portion is in the opposite direction to the suction direction of the suction covering portion in the protrusion forming region of the resin film, and the suction force of the molding portion is greater than the suction force of the suction covering portion.

11. The manufacturing apparatus of an assembled paper container according to claim 9 or 10, wherein the suction start timing of the molding portion is configured to be earlier than the suction start timing of the suction covering portion.

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