Assembled paper container manufacturing method and assembled paper container manufacturing device

Abstract

[Problem] To provide an assembled paper container that can suppress leaking or oozing of accommodated contents from an accommodation part of a container body. [Solution] An assembled paper container 1 comprises a container body 11 having an accommodation part 12, and a resinous film 3 coated on an inner surface of the container body 11, the assembled paper container 1 being characterized in that: the container body 11 has a bottom surface 121, a plurality of lateral surfaces 122, and a flange part 13; on an upper surface of the flange part 13, an upper folded-back piece 13a configuring a tip part of a step 22 is pressed on the upper surface of a lower folded-back piece 13b, the step 22 being generated when the folded-back pieces 13a and 13b are bonded so as to overlap each other after assembly, and extending outward from the accommodation part 12 side; a rear end that continues to this tip part has the upper folded-back piece 13a pushed into the lower folded-back piece 13b side, shrinking the step 22; and the resinous film 3 is also roughly flat above the step 22.

Description

[Technical Field]

[0001] This invention ,set The present invention relates to a method for manufacturing a stand-up paper container and an apparatus for manufacturing this stand-up paper container. [Background technology]

[0002] Conventionally, there has been known a knockdown paper container in which a tray-shaped container body having a flange portion at the upper end is assembled from blank sheets made primarily of paper. Some of these knockdown paper containers have a thermoplastic resin film with resin properties attached to the inner surface of the container body, including the upper surface of the flange portion (see Patent Documents 1 and 2, etc.). Because of their resin properties, knockdown paper containers with resin films are primarily used as trays or bowls for holding food, etc.

[0003] Furthermore, compared to plastic containers, prefabricated paper containers are environmentally friendly products, for example, because they can suppress the generation of secondary microplastics in the environment. Furthermore, the resin film can be peeled off from the container body, and the resin film and the paper container body can be separated, allowing the resin film and the container body to be recycled separately. Due to these advantages, it is expected that prefabricated paper containers will be used as packaging containers for food and other items and storage containers for food and other items by applying, for example, Modified Atmosphere Packaging (MAP). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-293334 [Patent Document 2] Japanese Patent Application Publication No. 2019-172339 Summary of the Invention [Problem to be solved by the invention]

[0005] In the container body of such conventional assembled paper containers, a gap is formed on the upper surface of the flange portion due to the proximity of the end faces of the blank sheets. Currently, it is difficult to completely fill this gap even if the inner surface of the container body, including the upper surface of the flange portion, is covered with a resin film. Furthermore, because the resin film is thin, if this resin film is applied to the inner surface of the container body, including the upper surface of the flange portion, for example, by vacuum pressure, the resin film is sucked into the gap, making it difficult to close the gap with this resin film alone.

[0006] Furthermore, packaging methods have been developed that replace the air in the container body's storage compartment with a food gas suitable for food packaging (e.g., MAP). When this packaging method is applied to a prefabricated paper container with a resin film, a top seal is attached to the resin film on the upper surface of the flange. However, because the top seal is also thin, even when the top seal is attached to the resin film, a cavity is created along the gap between the upper surface of the resin film and the lower surface of the top seal. In other words, it is difficult to completely seal the cavity even with the top seal. Moreover, both ends of the cavity are open. Therefore, the storage compartment of the container body is connected to the outside of the container body through this cavity.

[0007] For the reasons described above, even if the storage section of an assembled paper container with a resin film is covered with a top seal, there is a risk that the contents may leak or seep out of the storage section through the cavity.

[0008] The present invention has been devised in view of the above-mentioned problems, and its object is to provide a device capable of preventing leakage or seepage of the contents from the storage portion of the container body. Group The present invention provides a method for manufacturing a stand-up paper container and an apparatus for manufacturing the stand-up paper container. [Means for solving the problem]

[0013] The manufacturing method of an assembled paper container according to the first invention is a manufacturing method of an assembled paper container which is assembled from blank sheets whose main material is paper and which includes a container body having a storage section and a resin film coated on the inner surface of the container body, and which includes the steps of: raising a plurality of side surfaces from the bottom surface of the blank sheet to form the storage section of the container body; folding back the upper portions of the plurality of side surfaces; and bonding the folded-back pieces of the blank sheet together so that they overlap each other; The folded piece a box-making process for assembling the container body by forming a flange portion extending outward from the containing portion on the upper surface thereof; a lower mold for placing the resin film on the inner surface of the container body assembled in the box-making process, and the container body being placed thereon; a suction covering portion provided in the lower mold for sucking air between the resin film and the resin film to cover the inner surface of the container body with the resin film; an upper mold facing the lower mold and sandwiching the resin film between the lower mold and the resin film; a flange pressing portion received in the upper mold for pressing the flange portion of the container body and the resin film on the flange portion; and a step-reducing recess provided in the lower mold below the flange pressing portion of the upper mold. the surface of the area crossing the step is sucked by the suction covering part, the upper folded piece forming the tip of the step is pressed toward the lower mold with the upper side surface of the lower folded piece via the flange pressing part, and the rear end part continuous with the tip part is pushed together with the lower folded piece via the flange pressing part toward the step reduction recess which is arranged on the side of the lower folded piece and has a width less than the length between the edges of the upper folded piece, causing the lower folded piece to bulge downward in the area contacting the upper folded piece, thereby reducing the step, and also removing air between the container body and the resin film from the gap around both, and covering the inner surface of the container body with the resin film.

[0014] No. 2 The method for manufacturing an assembled paper container according to the present invention is as follows: 1The invention is characterized in that after the step reduction / resin film covering step, a top seal attaching step is further provided, in which a top seal is attached to the resin film covering the upper surface of the flange portion above the upper surface of the flange portion so as to cross the step while pressing the upper portions of the leading and trailing ends of the step.

[0015] The manufacturing device for assembled paper containers according to the third invention is a manufacturing device for assembled paper containers that is assembled from blank sheets whose main material is paper and includes a container body having a storage section, and a resin film covering the inner surface of the container body, and includes a lower mold on which the container body is placed, a suction covering section that is provided in the lower mold and sucks air between the resin film and the container body, causing the resin film to cover the inner surface of the container body, an upper mold that faces the lower mold and sandwiches the resin film between it and the lower mold, and a suction covering section that is accommodated in the upper mold and holds the container body. The folded pieces are folded at the upper portions of the side surfaces that form the storage section, and overlap each other, so that there are steps on the upper surfaces of the folded pieces that extend outward from the storage section. a flange pressing portion that presses the flange portion and the resin film on the flange portion; and a step reduction recess that is provided in the lower mold below the flange pressing portion of the upper mold, and the resin film is placed on the resin film to reduce the thickness of the container body. The aforementioned Flange part The aforementioned When the surface of the area crossing the step is sucked by the suction covering portion, the upper folded piece forming the tip of the step is crushed by the upper side of the lower folded piece toward the lower mold via the flange pressing portion, and the rear end portion continuous with the tip is pressed together with the lower folded piece via the flange pressing portion toward the step reduction recess which is arranged on the side of the lower folded piece and has a width less than the length between the edges of the upper folded piece, thereby causing the lower folded piece to bulge downward in the area where it contacts the upper folded piece, thereby reducing the step.

[0016] No. 4 The manufacturing device for assembled paper containers according to the present invention is 3This is an apparatus for manufacturing assembled paper containers that covers the storage section by attaching a top seal to the resin film that covers the upper surface of the flange portion of an assembled paper container manufactured by the apparatus for manufacturing assembled paper containers of the invention, and is characterized in that it comprises a seal head that is arranged above the top seal and a seal bucket that is arranged below the assembled paper container, and the upper part of the seal bucket is made of an elastic material and the lower part of the seal bucket is made of a hard material. [Effects of the Invention]

[0017] According to the present invention having the above-mentioned configuration, it is possible to provide a knockdown paper container that can prevent the contents from leaking or seeping out from the storage section of the container body. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1(a) is a plan view showing an assembly-type paper container according to an embodiment of the present invention, FIG. 1(b) is a side view showing the assembly-type paper container of FIG. 1(a), and FIG. 1(c) is a perspective view showing the assembly-type paper container of FIG. 1(a). [Figure 2] FIG. 2 is a development view showing a blank sheet used in the assembly-type paper container of FIG. [Figure 3] FIG. 3 is an enlarged cross-sectional view of the portion seen from the arrow AA in FIG. [Figure 4] FIG. 4 is a plan view showing an aspect in which the storage section of the assembly-type paper container of FIG. 1 is covered with a top seal. [Figure 5] 5(a) is an enlarged cross-sectional view of the portion viewed from the arrow BB in FIG. 4, and FIG. 5(b) is an enlarged view of a portion C in FIG. 5(a). [Figure 6] FIG. 6 is a flowchart showing steps in a method for manufacturing a prefabricated paper container according to an embodiment of the present invention. [Figure 7] 7(a) and 7(b) are schematic cross-sectional views showing an example of an apparatus for manufacturing an assembly-type paper container according to an embodiment of the present invention. [Figure 8]8(a) to 8(c) are explanatory views for explaining the main parts of the manufacturing apparatus of FIG. 7 in an enlarged manner. [Figure 9] FIG. 9 is a schematic block diagram showing an example of a manufacturing system for assembly-type paper containers according to an embodiment of the present invention. [Figure 10] Figures 10(a) to 10(c) are explanatory diagrams for enlarging and explaining the main parts of a press machine as a manufacturing device for assembly-type paper containers that attaches top seals to assembly-type paper containers in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

[0020] [Embodiment] As shown in Figs. 1(a) to 1(c), the collapsible paper container 1 according to the embodiment of the present invention comprises a container body 11 and a resin film 3 covering the inner surface of the container body 11.

[0021] The container body 11 has a storage section 12 and a flange section 13. The container body 11 is assembled from a single blank sheet 2 made primarily of paper, as shown in FIG. 2. In FIG. 2, dotted lines indicate "valley folds" and dashed lines indicate "mountain folds." The valley folds and mountain folds are formed, for example, by perforations, half cuts, or ruled lines. The solid lines in the blank sheet 2 indicate "slits." The container body 11 is constructed by making "valley folds" and "mountain folds" in the blank sheet 2 and bonding the folded pieces 13a and 13b together so that they overlap each other.

[0022] In this embodiment, the storage section 12 has eight side surfaces 122 rising from the bottom surface 121. The storage section 12 can be configured with three or more side surfaces 122.

[0023] The flange portion 13 is continuous with the upper end of each side surface 122 and extends outward from the storage portion 12. The upper surface 131 of this flange portion 13 has two steps 22 at each of the four corners, which extend outward from the storage portion 12 side and are formed when the folded pieces 13a, 13b of the blank sheet 2 are attached to each other so that they overlap after assembly.

[0024] 3, the step 22 is reduced by the upper surface of the lower folded piece 13b squashing the area of ​​the edge 31 of the upper folded piece 13a on the step 22 side, and the lower folded piece 13b squashing toward the upper folded piece 13a. In addition, in FIGS. 1 and 4, a dotted line is provided inside the edge 31 of the upper folded piece 13a to indicate the range of the rear end portion squashed by the upper surface of the lower folded piece 13b.

[0025] The resin film 3 covers the inner surface of the container body 11, including the upper surface 131 of the flange portion 13. As shown in FIG. 3 , the resin of the resin film 3 flows into a step 22, filling the step 22.

[0026] Examples of resins suitable for use in the resin film 3 for covering the inner surface of the container body 11 include thermoplastic resins such as polyolefins such as polyethylene (PE) and polypropylene (PP), polyesters such as polyvinyl chloride and polyethylene terephthalate (PET), ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer, polyamide, polyvinylidene chloride, polystyrene, polycarbonate, polybutene, and polyvinyl alcohol. The resin film 3 may be a single film made of any of the above materials, or may be a film made of a mixture of two or more of the above materials. The resin film 3 may also be a single-layer film or a laminate film made of two or more layers.

[0027] Next, a description will be given of the knockdown paper container 1 in which the container section 12 is covered with a top seal 4, in addition to the above-mentioned embodiments.

[0028] As shown in Fig. 4, the collapsible paper container 1 can package and store food or other contents by covering the storage section 12 with the top seal 4. The top seal 4 is attached to the resin film 3 on the upper surface 131 of the flange section 13. In this way, the top seal 4 covers the storage section 12. In this embodiment, the top seal 4 is attached to the resin film 3 above the upper surface 131 of the flange section 13, crossing the step 22. When attaching the top seal 4 to the resin film 3, the top seal 4 is pressed while being heated by a press in a pressing area 32 indicated by a dotted line.

[0029] Here, as shown in Figures 5(a) and 5(b), above the step 22, the lower surface of the top seal 4 can be sufficiently thermocompressed to the upper surface of the resin film 3, and the top seal 4 can be firmly attached to the upper surface of the resin film 3.

[0030] In addition, the resin film 3 is formed so as to be folded in three or more layers at the step 22, which applies a reaction force to the top seal 4 during pressing, making it easier to thermocompress the lower surface of the top seal 4 to the upper surface of the resin film 3.

[0031] Next, a method for manufacturing the assembly-type paper container 1 according to the embodiment of the present invention will be described with reference to FIG.

[0032] First, in the manufacturing method of the assembly type paper container 1 according to the embodiment of the present invention, the blank sheet 2 is manufactured by performing the blank sheet cutting step S1 of cutting and forming the above-mentioned blank sheet 2.

[0033] Subsequently, a box-making process S2 is carried out in which the container body 11 is assembled from the blank sheets 2 manufactured by cutting in the blank sheet cutting process S1.

[0034] Next, a resin film 3 is placed on the inner surface of the container body 11 assembled in the box-making process S2, the surface of the area of ​​the resin film 3 that crosses the step 22 is sucked, the upper folded piece 13a that forms the tip of the step 22 is crushed by the upper surface of the lower folded piece 13b, and the rear end part that is continuous with this tip part is pushed toward the lower folded piece 13b to reduce this step 22, and at the same time, the air between the container body 11 and the resin film 3 is extracted from the gap around them using, for example, vacuum compressed air, while pressurizing the resin film 3 from above, thereby performing the step reduction / resin film covering process S3 in which the resin film 3 is covered on the inner surface of the container body 11. Although vacuum compressed air has been exemplified as a method for covering the container body 11 with the resin film 3, the air between the container body 11 and the resin film 3 may be removed simply by sucking it through the gap between the two or by applying pressure from above the resin film 3.

[0035] Next, a trimming process S4 is carried out to remove excess resin film 3 from around the assembled paper container 1 to which the top seal 4 produced in the step reduction / resin film covering process S3 has not yet been attached.

[0036] Subsequently, an article accommodating step S5 is carried out in which an article such as food is accommodated in the accommodating section 12 of the assemblable paper container 1 from which the excess peripheral resin film 3 has been removed in the trimming step S4.

[0037] Finally, a top seal attachment process S6 is carried out in which a top seal 4 is attached to the resin film 3 coated on the upper surface of the flange portion 13 of the assembled paper container 1 in a state in which food or other contents are contained in the storage portion 12 in the content storage process S5, using a pressing machine to press the upper parts of the front and rear ends of the step 22 above the upper surface of the flange portion 13 and across this step 22.

[0038] In this way, the assembly-type paper container 1 is manufactured, and the method for manufacturing the assembly-type paper container 1 according to this embodiment is completed.

[0039] Next, a manufacturing apparatus 600 for a prefabricated paper container 1 according to an embodiment of the present invention will be described with reference to FIG.

[0040] As shown in Figures 7(a) and 7(b), the manufacturing apparatus 600 for the assembly-type paper container 1 according to an embodiment of the present invention is a novel manufacturing apparatus capable of manufacturing the assembly-type paper container 1 according to this embodiment. This manufacturing apparatus 600 coats the resin film 3 on the container body 11 with the flange portion 13, and can reduce the step 22 during coating.

[0041] This manufacturing apparatus 600 includes a lower mold 610, a suction covering portion 611, an upper mold 620, a flange pressing portion 630, and a step reducing recess 610a (see FIGS. 8(a) to 8(c)).

[0042] The container body 11 is placed on the lower mold 610.

[0043] The suction covering part 611 is provided on the lower mold 610 and connected to a vacuum pump 640. The suction covering part 611 is configured to suck the resinous film 3 through the container body 11 placed on the lower mold 610 so that air escapes from the gap between the resinous film 3 and the periphery of the container body 11.

[0044] The upper mold 620 faces the lower mold 610 and is movable 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 is brought into close contact with the lower mold 610 with the resin film 3 sandwiched therebetween, a nearly sealed processing space is formed. In this processing space, the resin film 3 covers the housing portion 12 and the flange portion 13 by, for example, vacuum compressed air.

[0045] Flange pressing portion 630 is housed in upper mold 620. Flange pressing portion 630 is supported on top plate portion 621 of upper mold 620 by an expandable elastic member 632 such as a spring. Flange pressing portion 630 presses flange portion 13 and resin film 3 on flange portion 13, for example, under vacuum pressure.

[0046] Here, the manner in which the step 22 is reduced will be described.

[0047] As shown in Figures 8(a) to 8(c), the step-reducing recess 610a is provided in the lower mold 610 below the flange presser 630 of the upper mold 620, and has a width less than the distance between the edges 31, 31 of the upper folded piece 13a of the container body. First, a resin film 3 is placed, and the surface of the resin film 3 in the area that crosses the step 22 of the flange 13 of the container body 11 is suctioned by the suction covering part 611. At the same time, the area near the edge 31 of the upper folded piece 13a is crushed by the upper surface of the lower folded piece 13b and the flange presser 630, and the area inside the crushed edge 31 is pressed into the lower folded piece 13b, reducing the step 22. This reduces the thickness of the upper folded piece 13a and the lower folded piece 13b near the step 22 from their original thicknesses. Furthermore, by compressing the resin film 3 near the step 22 with the lower mold 610 and the flange pressing portion 630, the resin film 3 is poured into the step 22 side, filling the step 22 with resin. At this time, the step 22 does not need to be completely filled with the resin film 3, and some space may be left empty. In this embodiment, the suction covering portion 611 sucks the resin film 3 in the direction toward the container body 11.

[0048] Then, the container body 11 and the resin film 3 are placed and attached between the lower mold 610 having the step-reducing recess 610a and the flange pressing portion 630 so as to cross the step 22 of the flange portion 13.

[0049] Then, the flange pressing portion 630 is raised, and the assembly type paper container 1 is removed from the manufacturing apparatus 600.

[0050] Finally, excess resin film 3 is removed from the periphery of the assembly-type paper container 1 by trimming, and the assembly-type paper container 1 shown in Figs. 1 and 3 is completed.

[0051] In this way, the manufacturing device 600 for the assembly type paper container 1 according to this embodiment makes it possible to manufacture the assembly type paper container 1.

[0052] Next, a manufacturing system 700 for a prefabricated paper container 1 according to an embodiment of the present invention will be described with reference to FIG.

[0053] The manufacturing system 700 for an assembled paper container 1 according to an embodiment of the present invention coats the container body 11 with a flange portion 13 with the resin film 3 while winding the resin film 3 wound around a feed roller 710 with a winding roller 720.

[0054] As shown in FIG. 9, this manufacturing system 700 includes a feed roller 710, a take-up roller 720, a heater 730, the manufacturing device 600, and a trimming machine 740.

[0055] A roll of strip-shaped resin film 3 is attached to the feed roller 710.

[0056] One end of the strip-shaped resin film 3 is attached to the winding roller 720, which winds up the strip-shaped resin film 3. The strip-shaped resin film 3 advances along the feed direction W from the feed roller 710 toward the winding roller 720.

[0057] The heater 730 is disposed between the feed roller 710 and the take-up roller 720 and heats the strip-shaped resin film 3 .

[0058] The manufacturing apparatus 600 is the one described above and is disposed between the heater 730 and the take-up roller 720 .

[0059] The trimming machine 740 is disposed between the manufacturing device 600 and the take-up roller 720, and trims the assemblable paper container 1 manufactured by the manufacturing device 600. In this way, the assemblable paper container 1 is separated from the strip-shaped resin film 3.

[0060] As described above, the manufacturing system 700 for the assembly-type paper container 1 according to this embodiment includes the manufacturing device 600. Therefore, the manufacturing system 700 can manufacture the assembly-type paper container 1. Moreover, the manufacturing system 700 can continuously manufacture the assembly-type paper container 1 from the strip-shaped resin film 3.

[0061] Finally, using Figures 10(a) to 10(c), we will explain a pressing machine as a manufacturing apparatus according to an embodiment of the present invention, which attaches a top seal 4 to the resin film 3 covering the upper surface of the flange portion 13 of the assembled paper container 1 manufactured by the above-mentioned manufacturing apparatus 600, thereby covering the storage portion 12.

[0062] As shown in Figures 10(a) to 10(c), this pressing machine is equipped with a seal head 810 arranged above the top seal 4, and seal buckets 820, 830 arranged below the assembled paper container 1. The seal bucket upper part 820 is made of an elastic material such as rubber, and the seal bucket lower part 830 is made of a hard material such as metal.

[0063] Then, the seal head 810 is lowered and heated to attach the top seal 4 to the flange portion 13 of the assemblable paper container 1, resulting in the usage form shown in Figures 4, 5(a) and 5(b).

[0064] Furthermore, since the seal bucket upper part 820 is made of an elastic material such as rubber, the elastic deformation of this seal bucket upper part 820 allows the outer part of the step 22 to be reliably pressed by a pressing machine when the top seal 4 is attached, as described above, and the step 22 can be further reduced as shown in Figures 5(a) and 5(b).

[0065] According to the embodiment of the present invention described above, the top seal 4 can be thermocompressed onto the upper surface of the resin film 3 above the step 22, and the top seal 4 can easily cover the upper surface of the resin film 3 above the step 22 even if there is a step 22.

[0066] Thus, according to this embodiment, an assembly-type paper container 1 can be provided that can prevent the contents from leaking or seeping out from the storage section 12 of the container body 11 by using the resin film 3 and the top seal 4.

[0067] Here, an experimental verification was carried out by preparing the same number of samples under the same conditions as possible for a prefabricated paper container not to which the present invention is applied and a prefabricated paper container 1 to which the present invention is applied, and comparing them. The verification results showed that in the prefabricated paper container not to which the present invention is applied, most samples suffered from leakage or seepage of the contained contents, but in the prefabricated paper container 1 to which the present invention is applied, no samples suffered from leakage or seepage of the contained contents from the container section 12 of the container body 11.

[0068] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0069] 1. Assembled paper container 11 Container body 12 Storage section 121 bottom 122 Side 13 Flange 131 Top surface 13a Folding piece 13b Folding piece 2 blank sheets 22 steps 3. Resin film 31 Edge of upper folded piece 32 Pressed Area 4 Top seal 600 Manufacturing equipment 610 Lower mold 610a Step reduction recess 611 Suction covering part 620 upper mold 621 Top plate 630 Flange holder 632 Elastic Members 640 Vacuum Pump 700 Manufacturing System 710 Feeding roller 720 Winding roller 730 heating machine 740 Trimming Machine 810 Seal Head 820 Seal bucket upper part 830 Seal bucket bottom S1 Blank sheet cutting process S2 Box manufacturing process S3 Step reduction and resin film coating process S4 Trimming process S5 Storage process S6 Top seal attachment process W Feed direction

Claims

1. A method for manufacturing an assembly-type paper container, which includes a container body having a storage section and assembled from blank sheets made mainly of paper, and a resin film coated on the inner surface of the container body, a box-making process in which a plurality of side surfaces are raised from the bottom surface of the blank sheet to form the storage section of the container body, and the upper portions of the plurality of side surfaces are folded back, and the folded pieces of the blank sheet are attached together so that they overlap, so that the upper surfaces of the folded pieces have steps extending outward from the storage section and flanges extending outward from the storage section, thereby assembling the container body; The resin film is placed on the inner surface of the container body assembled in the box-making process, and the surface of the region of the resin film that crosses the step is sucked by the suction covering part using a manufacturing device that includes: a lower mold on which the container body is placed; a suction covering part that is provided in the lower mold and sucks air between the resin film and the inner surface of the container body so that the resin film covers the inner surface of the container body; an upper mold that faces the lower mold and sandwiches the resin film between the lower mold and the upper mold; a flange pressing part that is housed in the upper mold and presses the flange part of the container body and the resin film on the flange part; and a step-reducing recess that is provided in the lower mold below the flange pressing part of the upper mold. and a step reducing / resin film covering step in which the upper folded piece forming the tip portion of the container body is crushed by the upper side surface of the lower folded piece toward the lower mold via the flange pressing portion, and the rear end portion continuous with the tip portion is pressed together with the lower folded piece via the flange pressing portion toward the step reducing recess that is disposed on the side of the lower folded piece and has a width less than the length between the edges of the upper folded piece, thereby causing the lower folded piece to bulge downward in an area where it contacts the upper folded piece, thereby reducing the step and also allowing air between the container body and the resin film to escape from a gap around both, thereby covering the inner surface of the container body with the resin film. A method for manufacturing an assembled paper container, characterized by:

2. After the step reducing / resin film covering step, the method further includes a top seal attaching step of attaching a top seal to the resin film covering the upper surface of the flange portion above the upper surface of the flange portion so as to cross the step while pressing upper portions of the leading and trailing ends of the step. The method for manufacturing an assembled paper container according to claim 1,

3. A manufacturing device for an assembled paper container, which includes a container body having a storage section and assembled from blank sheets made primarily of paper, and a resin film coated on the inner surface of the container body, a lower mold on which the container body is placed; a suction covering portion provided in the lower mold for sucking air between the resin film and the resin film to cover the inner surface of the container body; an upper mold that faces the lower mold and has the resin film sandwiched between the upper mold and the lower mold; a flange portion that is accommodated in the upper mold and has folded pieces that are folded at the upper portions of the side surfaces of the container body and that form the accommodation portion overlap each other, and that has a step on the upper surface of the folded piece that extends outward from the accommodation portion; and a flange pressing portion that presses the resin film on the flange portion; a step-reducing recess provided in the lower mold below the flange pressing portion of the upper mold; Equipped with When the resin film is placed and the surface of the region of the resin film that crosses the step of the flange portion of the container body is suctioned by the suction covering portion, the upper folded piece that forms the tip end of the step is crushed by the upper side surface of the lower folded piece toward the lower mold via the flange pressing portion, and the rear end portion that is continuous with the tip end is pressed together with the lower folded piece via the flange pressing portion toward the step reducing recess that is arranged on the side of the lower folded piece and has a width less than the length between the edges of the upper folded piece, thereby causing the lower folded piece to bulge downward in the region that contacts the upper folded piece, thereby reducing the step. An apparatus for manufacturing assembled paper containers, characterized by:

4. A manufacturing apparatus for assembled paper containers, which covers the containing portion by attaching a top seal to the resin film covering the upper surface of the flange portion of the assembled paper container manufactured by the manufacturing apparatus for assembled paper containers according to claim 3, a seal head disposed above the top seal; a seal bucket disposed below the assembled paper container; The upper part of the seal bucket is made of an elastic member, The lower part of the seal bucket is made of a hard material. An apparatus for manufacturing assembled paper containers, characterized by:

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