paper container

Abstract

To provide a paper container that can improve the adhesion between the container body and the resin film. [Solution] The paper container 100 according to the present invention is a paper container comprising a tray-shaped paper base material 110 and a resin film 120 attached to the inner surface of the paper base material 110, wherein the paper base material 110 includes a bottom portion 10, a plurality of side wall portions 20 provided along the periphery of the bottom portion 10, and a flange portion 60 provided along the upper end of the plurality of side wall portions 20, wherein the first side wall portion 20a of the plurality of side wall portions 20 is connected to the bottom portion 10 via a straight first fold portion 30a, the first fold portion 30a has a first portion 33 having a first through portion 31 and a first non-through portion 32, and a second portion 36 having a second through portion 34 that is longer than the first through portion 31, and the end of the first fold portion 30a is composed of the first non-through portion 32.

Description

Technical Field

[0001] The present invention relates to a paper container.

Background Art

[0002] Conventionally, a paper container formed by molding a paper base material into a tray shape and attaching a resin film to the molded paper base material is known. Such a paper container is used, for example, for storing foods and the like.

[0003] For example, Patent Document 1 describes a method for manufacturing an assembled paper container including a box-making process of assembling a tray-shaped container body from a blank sheet mainly made of paper, and a resin film coating process of coating the inner surface of the assembled container body with a resin film. In the box-making process, a plurality of side surfaces are raised from the bottom surface of the blank sheet, and a gap is formed at the inner corner where the plurality of side surfaces are close to or in contact with each other. In the resin film coating process, air is sucked from the gap to coat the resin film.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the assembled paper container as described above, it is desired to improve the adhesion between the container body and the resin film.

[0006] One of the objects according to some aspects of the present invention is to provide a paper container capable of improving the adhesion between a paper base material and a resin film.

Means for Solving the Problems

[0007] One aspect of the paper container according to the present invention is A paper container comprising a tray-shaped paper substrate and a resin film attached to the inner surface of the paper substrate, The aforementioned paper substrate is The bottom and, Multiple side wall portions provided along the periphery of the bottom portion, A flange portion provided along the upper end of the plurality of side wall portions, Includes, The first side wall portion of the plurality of side wall portions is connected to the bottom portion via a straight first folded line portion. The first folded section is, A first part having a first penetrating portion and a first non-penetrating portion, A second portion having a second through-hole that is longer than the first through-hole, It has, The end of the first folded portion is composed of the first non-penetrating portion.

[0008] In one embodiment of the paper container according to the present invention, The ratio of the sum of the length of the portion where the first through-section is formed and the length of the portion where the second through-section is formed to the length of the first folded portion may be 60% or more and 90% or less. .

[0009] In one embodiment of the paper container according to the present invention, The aforementioned ratio may be between 75% and 85%.

[0010] In one embodiment of the paper container according to the present invention, In the first folded portion, the first portion and the second portion may be arranged alternately.

[0011] In one embodiment of the paper container according to the present invention, A first projection that protrudes outward from the first side wall, Of the plurality of side wall portions, a second projection protrudes outward from the second side wall portion connected to the bottom portion via a second fold line portion facing the first fold line portion, Includes, The lower end of the first projection and the lower end of the second projection may be parallel to the bottom.

[0012] In one aspect of the paper container according to the present invention, The flange portion is connected to the first side wall portion via a linear third fold line portion. The third fold line portion has a third through portion and a second non-through portion. The thickness of the second non-through portion may be half or less of the thickness of the flange portion.

[0013] In one aspect of the paper container according to the present invention, The width of the flange portion may be 5.0 mm or more and 10.0 mm or less.

[0014] In one aspect of the paper container according to the present invention, Among the plurality of side wall portions, the third side wall portion is adjacent to the first side wall portion. The flange portion is connected to the first side wall portion via a linear third fold line portion. The upper end of the third side wall portion contacts the flange portion. The difference between the distance between the upper end and the lower end of the first side wall portion and the distance between the upper end and the lower end of the third side wall portion may be the same as the thickness of the flange portion.

[0015] In one aspect of the paper container according to the present invention, including flap portions provided at both edge portions of the third side wall portion among the plurality of side wall portions The third side wall portion is adjacent to the first side wall portion. The flap portion overlaps the first side wall portion and constitutes the inner surface of the paper base material. The flap portion may contact the lower end of the third side wall portion.

Advantages of the Invention

[0016] According to the paper container of the present invention, the first side wall portion among the multiple side wall portions is connected to the bottom portion via a straight first fold line portion, and the first fold line portion has a first part having a first through portion and a first non-through portion, and a second part having a second through portion that is longer than the first through portion, and the end of the first fold line portion is made up of the first non-through portion, so that the adhesion between the container body and the resin film can be improved. [Brief explanation of the drawing]

[0017] [Figure 1] A schematic plan view of a paper container according to the first embodiment. [Figure 2] A schematic bottom view of a paper container according to the first embodiment. [Figure 3] A schematic plan view showing a paper container according to the first embodiment. [Figure 4] A schematic side view showing a paper container according to the first embodiment. [Figure 5] A schematic cross-sectional view showing a paper container according to the first embodiment. [Figure 6] A schematic diagram showing the unfolded view of the paper substrate of the paper container according to the first embodiment. [Figure 7] A schematic cross-sectional view showing the manufacturing process of a paper container according to the first embodiment. [Figure 8] A schematic cross-sectional view showing the manufacturing process of a paper container according to the first embodiment. [Figure 9] A schematic cross-sectional view showing the manufacturing process of a paper container according to the first embodiment. [Figure 10] A schematic cross-sectional view showing the manufacturing process of a paper container according to the first embodiment. [Figure 11] A schematic cross-sectional view showing the manufacturing process of a paper container according to the first embodiment. [Figure 12] A schematic plan view of a paper container according to the second embodiment. [Figure 13] A schematic bottom view perspective showing a paper container according to the second embodiment. [Figure 14] A schematic plan view showing a paper container according to the second embodiment. [Figure 15]A schematic side view showing a paper container according to the second embodiment. [Figure 16] A schematic diagram showing the unfolded view of the paper substrate of the paper container according to the second embodiment. [Figure 17] A schematic bottom view perspective showing a paper container according to the third embodiment. [Figure 18] A schematic plan view showing a paper container according to the third embodiment. [Figure 19] A schematic diagram showing the unfolded view of the paper substrate of a paper container according to the third embodiment. [Modes for carrying out the invention]

[0018] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. The embodiments described below are not intended to unduly limit the scope of the present invention as described in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0019] 1. First Embodiment 1.1. Structure First, the paper container according to the first embodiment will be described with reference to the drawings. Figure 1 is a schematic plan view perspective of the paper container 100 according to the first embodiment. Figure 2 is a schematic bottom view perspective of the paper container 100 according to the first embodiment. Figure 3 is a schematic plan view of the paper container 100 according to the first embodiment. Figure 4 is a schematic side view of the paper container 100 according to the first embodiment. Figure 5 is a schematic cross-sectional view of the paper container 100 according to the first embodiment along line VV in Figure 1. Figure 6 is a schematic diagram showing the unfolded view of the paper base material 110 of the paper container 100 according to the first embodiment.

[0020] As shown in Figure 5, the paper container 100 includes a paper base material 110 and a resin film 120. For convenience, the resin film 120 is not shown in Figures 1 to 4.

[0021] The paper substrate 110 has a tray-like shape. The thickness of the paper substrate 110 is, for example, 0.2 mm or more and 2.0 mm or less, preferably 0.5 mm or more and 1.5 mm or less. The material of the paper substrate 110 is paper. The paper substrate 110 is composed of pulp. The material of the paper substrate 110 may be paper to which additives have been added.

[0022] As shown in Figures 1 to 6, the paper substrate 110 includes, for example, a bottom portion 10, a side wall portion 20, a fold line portion 30, a first projection portion 40, a second projection portion 42, a flap portion 50, a flange portion 60, and a fold line portion 70.

[0023] The bottom portion 10 forms the base of the tray-shaped paper substrate 110. In a plan view, the shape of the bottom portion 10 is, for example, a rectangle. In the illustrated example, the shape of the bottom portion 10 in a plan view is a rectangle. Although not shown in the illustration, the shape of the bottom portion 10 in a plan view may also be a square.

[0024] Multiple side wall sections 20 are provided. The multiple side wall sections 20 are provided along the periphery of the bottom section 10. An opening 22 is formed by multiple side wall portions 20. The opening 22 is located on the opposite side of the bottom portion 10. As shown in Figure 5, the angle θ of the side wall portion 20 with respect to the bottom portion 10 is obtuse, as shown in Figure 5. The angle θ is, for example, greater than 90° and less than or equal to 135°. In the examples shown in Figures 3 and 6, there are four side wall portions 20. Of the multiple side wall portions 20, side wall portions 20a and 20b face each other. Side wall portions 20a and 20b have the same shape as each other. Of the multiple side wall portions 20, side wall portions 20c and 20d face each other. Side wall portions 20c and 20d have the same shape as each other. The side wall portions 20 are connected to the bottom portion 10 via folded line portions 30.

[0025] The fold line portion 30 is provided between the bottom portion 10 and the side wall portion 20. The fold line portion 30 is straight. In the paper substrate 110 before molding shown in Figure 6, the side wall portion 20 is bent relative to the bottom portion 10 by valley folding the paper substrate 110 along the fold line portion 30. Multiple fold line portions 30 are provided, corresponding to multiple side wall portions 20. In the illustrated example, four fold line portions 30 are provided.

[0026] One of the multiple folded line sections 30, folded line section 30a is provided between the bottom section 10 and the side wall section 20a. The side wall section 20a is connected to the bottom section 10 via folded line section 30a. One of the multiple folded line sections 30, folded line section 30b is provided between the bottom section 10 and the side wall section 20b. Folded line section 30b faces folded line section 30a. The side wall section 20b is connected to the bottom section 10 via folded line section 30b. One of the multiple folded line sections 30, folded line section 30c is provided between the bottom section 10 and the side wall section 20c. Folded line section 30c connects folded line section 30a and folded line section 30b. The side wall section 20c is connected to the bottom section 10 via folded line section 30c. One of the multiple folded line sections 30, folded line section 30d, is provided between the bottom section 10 and the side wall section 20d. The folded line portion 30d faces the folded line portion 30c and connects the folded line portions 30a and 30b. The side wall portion 20d is connected to the bottom portion 10 via the folded line portion 30d. The length of the folded line portion 30a is smaller than the lengths of the folded line portions 30c and 30d. The length of the folded line portion 30b is smaller than the lengths of the folded line portions 30c and 30d. Although not shown in the figures, the length of the folded line portion 30a may be the same as the lengths of the folded line portions 30c and 30d, and the length of the folded line portion 30b may be the same as the lengths of the folded line portions 30c and 30d.

[0027] As shown in Figure 6, the folded portion 30 has, for example, a first portion 33 having a through portion 31 and a non-through portion 32, and a second portion 36 having a through portion 34 and a non-through portion 35. The folded portion 30 is composed of, for example, the first portion 33 and the second portion 36.

[0028] In the first portion 33 of the fold line section 30, through-sections 31 and non-through-sections 32 are provided alternately. In the illustrated example, in the first portion 33, there are two through-sections 31 and three non-through-sections 32. In the first portion 33, the multiple through-sections 31 are arranged at predetermined intervals. The first portion 33 constitutes a perforation. The through-sections 31 penetrate the paper substrate 110. The through-sections 31 are provided in a straight line. The length of the through-sections 31 is, for example, 1.0 mm or more and 5.0 mm or less, preferably 2.0 mm or more and 4.0 mm or less.

[0029] In the second portion 36 of the folded line portion 30, for example, multiple through portions 34 are provided. In the illustrated example, in the second portion 36, two through portions 34 are provided and one non-through portion 35 is provided. In the second portion 36, the non-through portion 35 is provided between the two through portions 34. The through portions 34 penetrate the paper substrate 110. The through portions 34 are provided in a straight line. The length of the through portion 34 is greater than the length of the through portion 31. The length of the through portion 34 is greater than the length of the non-through portion 35. The length of the through portion 34 is, for example, 10 mm or more and 50 mm or less, preferably 20 mm or more and 40 mm or less.

[0030] The ratio of the total length of the portion where the through portion 31 is formed and the portion where the through portion 34 is formed to the length of the folded portion 30 is, for example, 60% to 90%, and preferably 75% to 85%. Specifically, this ratio is the ratio of the total length of the multiple through portions 31 and the multiple through portions 34 to the length of one folded portion 30.

[0031] In the folded section 30, the first section 33 and the second section 36 are arranged alternately. The ends of the folded section 30 are composed of non-penetrating sections 32. Specifically, both ends of the folded section 30 are composed of non-penetrating sections 32. The corners of the bottom section 10 are composed of non-penetrating sections 32 of the folded sections 30 that are connected to each other.

[0032] The first projection 40 is provided on the side wall portion 20a. The first projection 40 protrudes outward from the side wall portion 20a. Two first projections 40 are provided on the side wall portion 20a. In the illustrated example, the first projection 40 protrudes outward from the edge connecting the upper end and lower end of the side wall portion 20a. The second projection 42 is provided on the side wall portion 20b. The second projection 42 protrudes outward from the side wall portion 20b. Two second projections 42 are provided on the side wall portion 20b. In the illustrated example, the second projection 42 protrudes outward from the edge connecting the upper end and lower end of the side wall portion 20b.

[0033] The lower end 41 of the first projection 40 and the lower end 43 of the second projection 42 are parallel to the bottom 10. Specifically, the lower ends 41 and 43 are parallel to the upper surface of the bottom 10. The lower ends 41 and 43 may extend horizontally.

[0034] The flap portion 50 is provided on the side wall portion 20c via the fold line portion 52. Furthermore, the flap portion 50 is provided on the side wall portion 20d via the fold line portion 52. Two flap portions 50 are provided on each of the side wall portions 20c and 20d. In the paper substrate 110 before molding shown in Figure 6, the flap portion 50 is bent relative to the side wall portions 20c and 20d by valley folding the paper substrate 110 along the fold line portion 52.

[0035] As shown in Figures 1 and 3, the flap portion 50 overlaps with the side walls 20a and 20b when the paper substrate 110 is molded into a tray shape. This increases the strength of the tray-shaped paper substrate 110. The flap portion 50 constitutes the inner surface of the tray-shaped paper substrate 110.

[0036] For example, an opening 54 is formed in the flap portion 50. The opening 54 penetrates the flap portion 50. The opening 54 increases the contact area between the side walls 20a, 20b and the resin film 120. This increases the strength of the tray-shaped paper substrate 110.

[0037] The flange portion 60 is provided along the upper ends of the multiple side wall portions 20. In other words, the flange portion 60 is provided along the opening 22 formed by the multiple side wall portions 20. The flange portion 60 surrounds the opening 22. The upper surface of the flange portion 60 is parallel to, for example, the upper surface of the bottom portion 10. In the illustrated example, the flange portion 60 is connected to the side wall portions 20a, 20b, 20c, and 20d via the folded line portion 70.

[0038] The width W of the flange portion 60 is, for example, 5.0 mm or more and 10.0 mm or less, preferably 7.5 mm or more and 9.5 mm or less. The width W of the flange portion 60 is the shortest distance between the upper end of the side wall portion 20a and the outer circumference of the flange portion 60.

[0039] The fold line portion 70 is straight. In the paper substrate 110 before molding shown in Figure 6, by mountain folding the paper substrate 110 along the fold line portion 70, the flange portion 60 is formed by the side wall portions 20a, 20b, 2 It is bent at 0c and 20d. In the illustrated example, there are four bent sections 70. Of the multiple bent sections 70, bent section 70a is provided between the side wall section 20a and the flange section 60. The flange section 60 is connected to the side wall section 20a via the bent section 70a.

[0040] As shown in Figure 6, the folded portion 70 has, for example, a through portion 71 and a non-through portion 72. The folded portion 70 is composed of, for example, a through portion 71 and a non-through portion 72. The through portions 71 and the non-through portions 72 are provided alternately. Multiple through portions 71 are arranged at predetermined intervals. The through portions 71 penetrate the paper substrate 110. The through portions 71 are provided in a straight line. In the non-through portions 72, the paper substrate 110 is half-cut. The thickness of the non-through portion 72 is less than half the thickness of the flange portion 60.

[0041] As shown in Figure 5, the resin film 120 is attached to the inner surface of the tray-shaped paper substrate 110. Specifically, the resin film 120 is attached to the bottom 10, the side wall 20, the flap 50, and the flange 60. The adhesive force of the resin film 120 to the paper substrate 110 allows the paper substrate 110 to maintain its tray shape. The thickness of the resin film 120 is less than the thickness of the flap 50. In a plan view, the resin film 120 has a non-overlapping portion 122 that does not overlap with the paper substrate 110. The non-overlapping portion 122 protrudes from the flange 60. When disposing of a used paper container 100, the user can pinch the non-overlapping portion 122 and peel the resin film 120 from the paper substrate 110. This allows the paper substrate 110 and the resin film 120 to be disposed of separately. Note that the non-overlapping portion 122 is not required. In other words, in a plan view, the resin film 120 may be provided so as not to protrude from the paper substrate 110.

[0042] The material of the resin film 120 is a thermoplastic resin. Examples of thermoplastic resins include polypropylene, polyethylene, polyvinyl chloride, polystyrene, acrylic resin, polyester resin, polyethylene terephthalate, polyphenylene ether, polybutylene terephthalate, nylon, polyamide, polycarbonate, polyacetal, polyphenylene sulfide, and polyether ether ketone. These resins may be used individually or in appropriate mixtures. The resin film 120 may be colorless and transparent. The resin film 120 may be formed by laminating multiple resin films or by co-extruding resin.

[0043] 1.2. Manufacturing method Next, the manufacturing method of the paper container 100 according to the first embodiment will be described with reference to the drawings. Figures 7 to 11 are schematic cross-sectional views showing the manufacturing process of the paper container 100 according to the first embodiment.

[0044] As shown in Figure 6, the base paper is punched out to form fold lines 30, 52, and 70, thereby creating a paper substrate 110.

[0045] As shown in Figure 7, the paper substrate 110 is placed in the mold 130. Specifically, the bottom portion 10 and the side wall portion 20 are placed in the recess 132 of the mold 130, and the flange portion 60 is placed on the upper surface of the mold 130. This allows the paper substrate 110 to be molded into a tray shape.

[0046] As shown in Figure 8, the resin film 120 is placed on top of the paper substrate 110, and the resin film 120 is heated to a stretchable softness. The heating method is not particularly limited.

[0047] As shown in Figure 9, the heated resin film 120 is pressed against the flange portion 60 with the sealing bar 134. Alternatively, the resin film 120 may be pressed against the flange portion 60 while being sucked.

[0048] As shown in Figure 10, the resin film 120 is sucked in through a suction hole 133 formed on the bottom surface of the recess 132. The resin film 120 is sucked in through the through-holes 31 and 34 of the folded portion 30. This allows the resin film 120 to be welded to the inner surface of the tray-shaped paper substrate 110. In a plan view, the suction hole 133 overlaps, for example, with the folded portion 30.

[0049] As shown in Figure 11, the sealing bar 134 is pulled upward to peel the paper container 100 from the sealing bar 134. The resin film 120 is then cut into a predetermined shape.

[0050] Through the above process, paper container 100 can be manufactured.

[0051] 1.3. Effects The paper container 100 includes a tray-shaped paper substrate 110 and a resin film 120 attached to the inner surface of the paper substrate 110. The paper substrate 110 includes a bottom portion 10, a plurality of side wall portions 20 provided along the periphery of the bottom portion 10, and a flange portion 60 provided along the upper ends of the plurality of side wall portions 20. One of the plurality of side wall portions 20, the side wall portion 20a (first side wall portion), is connected to the bottom portion 10 via a straight folded portion 30a (first folded portion). The folded portion 30a has a first part 33 having a through portion 31 (first through portion) and a non-through portion 32 (first non-through portion), and a second part 36 having a through portion 34 (second through portion) that is longer than the through portion 31. The end of the folded portion 30a is composed of the non-through portion 32.

[0052] As described above, in the paper container 100, the folded portion 30a has a second portion 36 having a through portion 34 that is longer than the through portion 31. Therefore, compared to the case where the second portion is not present, for example, the resin film 120 can be sufficiently sucked when it is sucked from the suction hole 133 formed on the bottom surface of the recess 132 and attached to the paper substrate 110. This improves the adhesion between the paper substrate 110 and the resin film 120. Furthermore, when molding the paper substrate 110, the side wall portion 20 can be easily bent relative to the bottom portion 10.

[0053] Furthermore, in the paper container 100, the end of the folded portion 30a is made of a non-penetrating portion 32, thus ensuring strength. For example, if the end of the folded portion is made of a penetrating portion, the strength will be reduced due to the presence of a penetrating portion at the corner of the bottom. Moreover, if a penetrating portion is present at the corner of the bottom, the contents of the paper container may be visible.

[0054] As described above, the paper container 100 can improve the adhesion between the paper substrate 110 and the resin film 120 while maintaining strength even with the penetrations 31 and 34 provided.

[0055] In the paper container 100, the ratio of the length of the portion with the through-hole 31 and the length of the portion with the through-hole 34 to the length of the folded portion 30a is 60% or more and 90% or less, preferably 75% or more and 85% or less. If this ratio is 60% or more, the resin film 120 can be sufficiently drawn in through the through-holes 31 and 34. If this ratio is 90% or less, the strength of the paper container 100 can be ensured.

[0056] In the paper container 100, the first portion 33 and the second portion 36 are arranged alternately in the folded portion 30a. Therefore, the paper container 100 can uniformly draw in the resin film 120 through the through portions 31 and 34.

[0057] The paper container 100 includes a first projection 40 that protrudes outward from the side wall portion 20a, and a second projection 42 that protrudes outward from a side wall portion 20b (second side wall portion) that is connected to the bottom portion 10 via a fold line portion 30b (second fold line portion) that faces the fold line portion 30a among the multiple side wall portions 20, and the lower end 41 of the first projection 40 and the lower end 43 of the second projection 42 are parallel to the bottom portion 10. Therefore, in the paper container 100, when multiple paper containers 100 are stacked, it is possible to prevent the upper paper container 100 from becoming stuck against the lower paper container 100 and becoming impossible to remove. In particular, since the lower ends 41 and 43 are parallel to the bottom 10, the contact area between the lower ends 41 and 43 of the upper paper container 100 and the flange portion 60 of the lower paper container 100 can be increased, and the force applied to the flange portion 60 of the lower paper container 100 can be distributed. As a result, it is possible to prevent the upper paper container 100 from becoming stuck against the lower paper container 100 and becoming impossible to remove.

[0058] In the paper container 100, the flange portion 60 is connected to the side wall portion 20a via a straight folded portion 70a (third folded portion). The folded portion 70a has a through portion 71 (third through portion) and a non-through portion 72 (second non-through portion), and the thickness of the non-through portion 72 is less than half the thickness of the flange portion 60. Therefore, in the paper container 100, the paper base material 110 before molding can be easily bent at the folded portion 70a.

[0059] In the paper container 100, the width W of the flange portion 60 is 5.0 mm or more and 10.0 mm or less. If the width W is 5.0 mm or more, the contact area between the flange portion 60 and the resin film 120 can be increased, and the adhesion force of the resin film 120 to the paper substrate 110 can be increased. If the width W is 10.0 mm or less, the flange portion 60 can be kept parallel to the bottom portion 10.

[0060] 2. Second Embodiment 2.1. Structure Next, the paper container according to the second embodiment will be described with reference to the drawings. Figure 12 is a schematic plan view perspective showing the paper container 200 according to the second embodiment. Figure 13 is a schematic bottom view perspective showing the paper container 200 according to the second embodiment. Figure 14 is a schematic plan view showing the paper container 200 according to the second embodiment. Figure 15 is a schematic side view showing the paper container 200 according to the first embodiment. Figure 16 is a schematic diagram showing the unfolded view of the paper base material 110 of the paper container 200 according to the second embodiment. For convenience, the resin film 120 is not shown in Figures 12 to 15.

[0061] Hereinafter, in the paper container 200 according to the second embodiment, components having the same function as the components of the paper container 100 according to the first embodiment described above will be denoted by the same reference numerals, and their detailed descriptions will be omitted.

[0062] In the paper container 100 described above, the shape of the bottom 10 was rectangular, as shown in Figures 1 to 3. In contrast, in the paper container 200, the shape of the bottom 10 is octagonal, as shown in Figures 12 to 14.

[0063] The paper container 200 includes eight side wall sections 20. Of the eight side wall sections 20, side wall sections 20a, 20b, 20c, and 20d are connected to the bottom section 10 via fold lines 30. A third projection 44 is provided on side wall section 20c. The third projection 44 protrudes outward from side wall section 20c. A fourth projection 46 is provided on side wall section 20d. The fourth projection 46 protrudes outward from side wall section 20d. The lower ends of the third projection 44 and the fourth projection 46 are parallel to the bottom section 10.

[0064] Of the eight side wall sections 20, side wall sections 20e, 20f, 20g, and 20h are connected to the bottom section 10 via folded line sections 80. The folded line sections 80 are composed of a plurality of through sections formed at predetermined intervals. Side wall sections 20e and 20f face each other. Side wall sections 20g and 20h face each other. Side wall sections 20e, 20f, 20g, and 20h have the same shape as each other. Each of the side wall sections 20e, 20f, 20g, and 20h is provided with a flap section 50. The flap section 50 is connected to side wall sections 20e, 20f, and 20g via folded line sections 52. It is connected to 20h. Note that in the illustrated example, no opening 54 is formed in the flap portion 50.

[0065] The upper ends of the side wall portions 20e, 20f, 20g, and 20h are in contact with the flange portion 60. The side wall portions 20e, 20f, 20g, and 20h are not connected to the flange portion 60 via the folded line portion. Side wall portion 20e is adjacent to side wall portion 20a. As shown in Figure 16, the difference between the distance D1 between the upper and lower ends of side wall portion 20a and the distance D2 between the upper and lower ends of side wall portion 20e is the same as the thickness of the flange portion 60.

[0066] The length of the upper end of the side wall sections 20e, 20f, 20g, and 20h is equal to the length of the lower end of the side wall sections 20e, 20f, 20g, and 20h, respectively. This prevents the upper paper container 200 from becoming stuck to the lower paper container 200 when multiple paper containers 200 are stacked. The shape of the side wall sections 20e, 20f, 20g, and 20h is rectangular. Although not shown in the illustration, the shape of the side wall sections 20e, 20f, 20g, and 20h may also be square.

[0067] The flange portion 60 has a connecting portion 62 connected to the folded line portion 70, and an extending portion 64 extending from the connecting portion 62 in the direction of extension of the folded line portion 70. The upper ends of the side wall portions 20e, 20f, 20g, and 20h are in contact with the flange portion 60 at the extending portion 64. The side wall portions 20e, 20f, 20g, and 20h support the extending portion 64. As shown in Figure 14, the extending portions 64 extending from adjacent connecting portions 62 are, for example, in contact with each other.

[0068] 2.2. Manufacturing method Next, a method for manufacturing the paper container 200 according to the second embodiment will be described. The method for manufacturing the paper container 200 according to the second embodiment is basically the same as the method for manufacturing the paper container 100 according to the first embodiment described above. Therefore, a detailed explanation will be omitted.

[0069] 2.3. Effects In the paper container 200, one of the multiple side wall portions 20, side wall portion 20e (third side wall portion), is adjacent to side wall portion 20a (first side wall portion), and the flange portion 60 is connected to side wall portion 20a via a straight folded line portion 70a (third folded line portion). The upper end of side wall portion 20e is in contact with the flange portion 60, and the difference between the distance D1 between the upper and lower ends of side wall portion 20a and the distance D2 between the upper and lower ends of side wall portion 20e is the same as the thickness of the flange portion 60. Therefore, in the paper container 200, the flange portion 60 can be supported by the side wall portion 20e. This allows the flange portion 60 to be kept parallel to the bottom portion 10.

[0070] Furthermore, the paper container 200 can have essentially the same effects as the paper container 100 described above.

[0071] 3. Third Embodiment 3.1. Structure Next, the paper container according to the third embodiment will be described with reference to the drawings. Figure 17 is a schematic bottom perspective view showing the paper container 300 according to the third embodiment. Figure 18 is a schematic plan view showing the paper container 300 according to the third embodiment. Figure 19 is a schematic diagram showing the unfolded view of the paper base material 110 of the paper container 300 according to the third embodiment. For convenience, the resin film 120 is omitted from Figures 17 and 18.

[0072] Hereinafter, in the paper container 300 according to the third embodiment, components having the same function as the components of the paper container 100 according to the first embodiment described above will be denoted by the same reference numerals, and their detailed descriptions will be omitted.

[0073] As shown in Figures 2 and 6, the paper container 100 described above was provided with protrusions 40 and 42.

[0074] In contrast, the paper container 300 does not have the protrusions 40 and 42, as shown in Figures 17 and 19.

[0075] The flap portion 50 is provided on both sides of the edges of a pair of side wall portions 20 among the multiple side wall portions 20. The flap portion 50 overlaps with the pair of side wall portions 20 and the adjacent side wall portion 20 to form the inner surface of the paper substrate 110. Of the multiple side wall portions 20, the side wall portions 20 other than the pair of side wall portions 20 are not provided with the flap portion 50. The pair of side wall portions 20 are connected to the bottom portion 10 via opposing fold lines 30.

[0076] Specifically, as shown in Figures 18 and 19, the paper substrate 110 includes a first flap portion 50a, a second flap portion 50b, a third flap portion 50c, and a fourth flap portion 50d as the flap portion 50.

[0077] The first flap portion 50a is provided on the first edge portion 90a of the side wall portion 20c. The first edge portion 90a connects the upper end and the lower end of the side wall portion 20c. The first flap portion 50a overlaps with the side wall portion 20a.

[0078] The second flap portion 50b is provided on the second edge portion 90b of the side wall portion 20c. The second edge portion 90b is the edge opposite to the first edge portion 90a and connects the upper end and lower end of the side wall portion 20c. The second flap portion 50b overlaps with the side wall portion 20b. The flap portions 50a and 50b are in contact with the lower end of the side wall portion 20c. The flap portions 50a and 50b are in contact with the folded line portion 30c. Although not shown in the illustration, the flap portions 50a and 50b do not have to be in contact with the lower end of the side wall portion 20c and the folded line portion 30c. In the illustrated example, the flap portions 50a and 50b are not in contact with the upper end of the side wall portion 20c.

[0079] The third flap portion 50c is provided on the third edge portion 90c of the side wall portion 20d. The third edge portion 90c connects the upper end and the lower end of the side wall portion 20d. The third flap portion 50c overlaps with the side wall portion 20b.

[0080] The fourth flap portion 50d is provided on the fourth edge portion 90d of the side wall portion 20d. The fourth edge portion 90d is the edge opposite to the third edge portion 90c and connects the upper and lower ends of the side wall portion 20d. The fourth flap portion 50d overlaps with the side wall portion 20b. The flap portions 50c and 50d are in contact with the lower end of the side wall portion 20d. The flap portions 50c and 50d are in contact with the folded line portion 30d. The flap portions 50a, 50b, 50c, and 50d are spaced apart from each other. The flap portions 50a, 50b, 50c, and 50d have the same shape as each other. Although not shown in the figures, the flap portions 50c and 50d do not necessarily have to be in contact with the lower end of the side wall portion 20d and the folded line portion 30d. In the illustrated example, the flap portions 50c and 50d are not in contact with the upper end of the side wall portion 20d.

[0081] 3.2. Manufacturing method Next, a method for manufacturing the paper container 300 according to the third embodiment will be described. The method for manufacturing the paper container 300 according to the third embodiment is basically the same as the method for manufacturing the paper container 100 according to the first embodiment described above. Therefore, a detailed explanation will be omitted.

[0082] 3.3. Effects The paper container 300 includes flap portions 50 provided on both edges of a pair of side wall portions 20 among a plurality of side wall portions 20, and the pair of side wall portions 20 are connected by opposing fold lines 30 to the bottom The flap portion 50 is connected to the portion 10 and overlaps with the pair of side wall portions 20 and adjacent side wall portions 20 to form the inner surface of the paper substrate 110. Of the multiple side wall portions 20, the flap portion 50 is not provided on the side wall portions 20 other than the pair of side wall portions 20.

[0083] Specifically, in the paper container 300, the paper base material 110 includes a plurality of side wall portions 20, namely side wall portion 20a, side wall portion 20b, side wall portion 20c, and side wall portion 20d, and a flap portion 50, namely a first flap portion 50a, a second flap portion 50b, a third flap portion 50c, and a fourth flap portion 50d. The side wall portion 20a is connected to the bottom portion 10 via a fold line portion 30a, the side wall portion 20b is connected to the bottom portion 10 via a fold line portion 30b opposite to the fold line portion 30a, the side wall portion 20c is connected to the bottom portion 10 via a fold line portion 30c connecting the fold line portion 30a and the fold line portion 30b, and the side wall portion 20d is connected to the bottom portion 10 via a fold line portion 30d opposite to the fold line portion 30b. The first flap portion 50a is provided on the first edge 90a of the side wall portion 20c and overlaps with the side wall portion 20a; the second flap portion 50b is provided on the second edge 90b of the side wall portion 20c opposite to the first edge 90a and overlaps with the side wall portion 20b; the third flap portion 50c is provided on the third edge 90c of the side wall portion 20d and overlaps with the side wall portion 20a; and the fourth flap portion 50d is provided on the fourth edge 90d of the side wall portion 20d opposite to the third edge 90c and overlaps with the side wall portion 20b.

[0084] Therefore, when stacking paper containers 300, it is possible to suppress the difficulty in separating the paper containers 300. Specifically, when stacking paper containers 300, the flap portions 50a, 50b, 50c, and 50d of the lower paper container 300 come into contact with the surface of the side wall portion 20 of the upper paper container 300. The lower paper container 300 does not come into contact with the upper paper container 300 in any part other than the flap portions 50a, 50b, 50c, and 50d. In other words, the lower paper container 300 sandwiches the upper paper container 300 in the direction from the side wall portion 20a to the side wall portion 20b, but does not sandwich the upper paper container 300 in the direction from the side wall portion 20c to the side wall portion 20d. This suppresses the difficulty in separating the paper containers 300 when stacking them.

[0085] For example, if the upper paper container is sandwiched between the lower paper containers from both the first direction and the second direction perpendicular to the first direction, the lower and upper paper containers will fit together firmly, making it difficult for the paper containers to come apart.

[0086] In the paper container 300, the first flap portion 50a, the second flap portion 50b, the third flap portion 50c, and the fourth flap portion 50d are separated from each other. Therefore, when the paper containers 300 are stacked, a gap is created between the flap portions 50a and 50c, the side wall portion 20 of the lower paper container 300, and the side wall portion 20 of the upper paper container 300. Similarly, a gap is created between the flap portions 50b and 50d, the side wall portion 20 of the lower paper container 300, and the side wall portion 20 of the upper paper container 300. This prevents the paper containers 300 from becoming difficult to separate when stacked.

[0087] In the paper container 300, the length of the folded portion 30a is smaller than the lengths of the folded portions 30c and 30d, and the length of the folded portion 30b is smaller than the lengths of the folded portions 30c and 30d. That is, the flap portion 50 is provided on the side wall portion 20 which is connected to the bottom portion 10 via the folded portion 30 along the short side. Therefore, in the paper container 300, when the paper containers 300 are stacked, a gap can be secured enclosed by the flap portion 50, the side wall portion 20 of the lower paper container 300, and the side wall portion 20 of the upper paper container 300.

[0088] For example, if the flap portion is provided on the side wall portion connected to the bottom via a fold line along the long side, the side wall portion is prone to bending, and when paper containers are stacked, the side wall portion of the lower paper container and the side wall portion of the upper paper container may come into contact, making it impossible to secure a gap enclosed by the flap portion, the side wall portion of the lower paper container, and the side wall portion of the upper paper container.

[0089] In the paper container 300, the first flap portion 50a and the second flap portion 50b are in contact with the lower end of the side wall portion 20c, and the third flap portion 50c and the fourth flap portion 50d are in contact with the lower end of the side wall portion 20d. Therefore, in the paper container 300, the contact area between the flap portions 50a, 50c and the side wall portion 20a, and the contact area between the flap portions 50b, 50d and the side wall portion 20b can be increased. This makes it possible to increase the strength of the tray-type paper substrate 110. In the paper container 300, as described above, a through portion 34 is formed in the fold line portion 30 that is longer than the through portion 31, so even if the flap portions 50a, 50b are extended to the lower end of the side wall portion 20c, the resin film 120 can be sufficiently sucked when attaching the resin film 120 to the paper substrate 110.

[0090] In the paper container 300, the thickness of the resin film 120 is less than the thickness of the flap portion 50. Therefore, when stacking paper containers 300, a gap can be secured between the flap portion 50, the side wall portion 20 of the lower paper container 300, and the side wall portion 20 of the upper paper container 300. For example, if the thickness of the resin film is greater than the thickness of the flap portion, the gap may be narrowed by the resin film, and it may not be possible to secure the gap.

[0091] In the paper container 300, the angle θ between the side wall 20 and the bottom 10 is obtuse. Therefore, when stacking the paper containers 300, it is possible to prevent them from becoming difficult to separate.

[0092] The embodiments and variations described above are examples only and are not limited thereto. For example, each embodiment and each variation can be combined as appropriate.

[0093] The present invention is not limited to the embodiments described above, and various further modifications are possible. For example, the present invention includes configurations that are substantially identical to those described in the embodiments. A substantially identical configuration is, for example, a configuration that has the same function, method, and result, or a configuration that has the same purpose and effect. The present invention also includes configurations in which non-essential parts of the configuration described in the embodiments are replaced. Furthermore, the present invention includes configurations that produce the same effects or achieve the same purpose as the configuration described in the embodiments. Furthermore, the present invention includes configurations that add known technology to the configuration described in the embodiments. [Explanation of Symbols]

[0094] 10...bottom, 20,20a,20b,20c,20d,20e,20f,20g,20h...side wall part, 22...opening, 30,30a,30b,30c,30d...broken line part, 31...penetrating part, 32...non-penetrating part, 33...first part, 34...penetrating part, 35...non-penetrating part, 36...second part, 40...first protrusion, 41...bottom end, 42...second protrusion, 43...bottom end, 44...third protrusion, 46...fourth protrusion, 50...flap part, 50a...first flap part, 50b...second Flap section, 50c...Third flap section, 50d...Fourth flap section, 52...Folded line section, 54...Opening, 60...Flange section, 62...Connecting section, 64...Extended section, 70, 70a, 80...Folded line section, 90a...First edge section, 90b...Second edge section, 90c...Third edge section, 90d...Fourth edge section, 100...Paper container, 110...Paper base material, 120...Resin film, 122...Non-overlapping section, 130...Mold, 132...Recess, 133...Suction hole, 134...Seal bar, 200, 300...Paper container

Claims

1. A paper container comprising a tray-shaped paper substrate and a resin film attached to the inner surface of the paper substrate, The aforementioned paper substrate is The bottom and, Multiple side wall portions provided along the periphery of the bottom portion, A flange portion provided along the upper end of the plurality of side wall portions, Includes, The first side wall portion of the plurality of side wall portions is connected to the bottom portion via a straight first folded line portion. The first folded portion is, A first portion having a first penetrating portion and a first non-penetrating portion, A second portion having a second through-hole that is longer than the first through-hole, It has, A paper container in which the end of the first folded portion is formed by the first non-penetrating portion.

2. The paper container according to claim 1, wherein the ratio of the sum of the length of the portion in which the first through-hole is formed and the length of the portion in which the second through-hole is formed to the length of the first fold line portion is 60% or more and 90% or less.

3. The paper container according to claim 2, wherein the ratio is 75% or more and 85% or less.

4. The paper container according to claim 1 or 2, wherein in the first fold line portion, the first portion and the second portion are provided alternately.

5. The first projection protruding outward from the first side wall portion, Of the plurality of side wall portions, a second projection protrudes outward from the second side wall portion connected to the bottom portion via a second fold line portion facing the first fold line portion, Includes, The paper container according to claim 1 or 2, wherein the lower end of the first projection and the lower end of the second projection are parallel to the bottom.

6. The flange portion is connected to the first side wall portion via a straight third folded portion. The third folded portion has a third through portion and a second non-through portion, The paper container according to claim 1 or 2, wherein the thickness of the second non-penetrating portion is half or less the thickness of the flange portion.

7. The paper container according to claim 1 or 2, wherein the width of the flange portion is 5.0 mm or more and 10.0 mm or less.

8. The third side wall portion among the plurality of side wall portions is adjacent to the first side wall portion, The flange portion is connected to the first side wall portion via a straight third folded portion. The upper end of the third side wall portion is in contact with the flange portion, The paper container according to claim 1 or 2, wherein the difference between the distance between the upper and lower ends of the first side wall and the distance between the upper and lower ends of the third side wall is the same as the thickness of the flange.

9. This includes flap portions provided on both edges of the third side wall portion among the plurality of side wall portions. The third side wall portion is adjacent to the first side wall portion, The flap portion overlaps with the first side wall portion and constitutes the inner surface of the paper substrate. The paper container according to claim 1 or 2, wherein the flap portion is in contact with the lower end of the third side wall portion.

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