Paper container

Abstract

To provide a technique for improving the strength of a paper container.SOLUTION: A paper container comprises: a bottom face part; a side face part in which plural side face part panels extended from the bottom face part are folded up along an end part of the bottom face part; a flange part in which plural flange pieces extended from each of the plural side face part panels are folded at a fold line along an outer end part of the side face part; and a curl part which is provided at the outer end part side of the flange part, and in which the adjacent flange pieces are overlapped each other. The flange part has a flat part which is connected with the side face part via the fold line and is extended toward the curl part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to paper containers. [Background technology]

[0002] Currently, due to environmental concerns, efforts to reduce or eliminate the use of plastic are accelerating worldwide. Plastic materials have been mainly used for packaging containers such as food trays, but research is being conducted into packaging container materials that use paper instead of plastic materials. For example, Patent Document 1 discloses a drawn paper container manufactured by drawing a blank sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-262484 A Summary of the Invention [Problem to be solved by the invention]

[0004] Paper containers have the problem that their strength decreases when the paper base absorbs moisture from the contents or condensation water when the contents are thawed. The present disclosure aims to provide a technique for improving the strength of paper containers. [Means for solving the problem]

[0005] That is, the present disclosure provides the following <1> ~ <4> Regarding. <1> A bottom portion and a side portion in which a plurality of side panels extending from the bottom portion are folded up along an edge of the bottom portion; a flange portion in which a plurality of flange pieces extending from each of the plurality of side panel portions are bent along a folding line along an outer end portion of the side portion; A curl portion is provided on the outer end side of the flange portion and is wound in a state where adjacent flange pieces overlap each other; Equipped with The flange portion has a flat portion connected to the side surface portion via the folding line and extending toward the curled portion. Paper container. <2> The container has a water-resistant resin layer provided on at least the inner surface side of the container. <1> A paper container as described in claim 1. <3> The corners of the side surface are curved. <1> or <2> A paper container as described in claim 1. <4> The bottom surface portion is rectangular, At least a portion of the two side panels overlap with each other so that the side panel extending from the long side of the bottom portion faces outward and the side panel extending from the short side of the bottom portion faces inward, forming a corner of the side surface. <1> from <3> The paper container according to any one of claims 1 to 5. Effect of the Invention

[0006] According to the present disclosure, the strength of paper containers can be improved. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an external perspective view of a paper container according to an embodiment. [Diagram 2] FIG. 2 is a plan view of the paper container according to the embodiment, seen from above. [Diagram 3] FIG. 3 is a perspective view of a corner of the paper container according to the embodiment, seen from the outside. [Figure 4] FIG. 4 is a plan view of the blank sheet according to the embodiment as viewed from the inside. [Diagram 5] FIG. 5 is a perspective view of a paper container according to an embodiment. [Figure 6] FIG. 6 is a front view of the paper container according to the embodiment. [Figure 7]FIG. 7 is a rear view of the paper container according to the embodiment. [Figure 8] FIG. 8 is a plan view of the paper container according to the embodiment. [Figure 9] FIG. 9 is a bottom view of the paper container according to the embodiment. [Figure 10] FIG. 10 is a right side view of the paper container according to the embodiment. [Figure 11] FIG. 11 is a left side view of the paper container according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the configurations of the following embodiments are merely examples, and the present invention is not limited to the configurations of these embodiments.

[0009] <Embodiment> Fig. 1 is an external perspective view of a paper container according to an embodiment. Fig. 2 is a plan view of the paper container according to an embodiment, seen from above. The paper container 1 according to this embodiment is produced by folding and assembling a single blank sheet (an example of the "paper container base paper" of the present disclosure). The paper container 1 is used, for example, as a food container containing moisture, such as refrigerated foods.

[0010] As shown in FIG. 1 and FIG. 2, the paper container 1 includes a bottom portion 2 on which food or the like is placed, and a side portion 3 that surrounds the bottom portion 2 to form a space for accommodating the food together with the bottom portion 2. The bottom portion 2 has a rectangular planar shape, and a plurality of side portion panels 3A to 3D extend from each side of the rectangular bottom portion 2. The plurality of side portion panels are divided into side portion panels 3A and 3B extending from the long sides of the rectangular shape and side portion panels 3C and 3D extending from the short sides of the rectangular shape. The side portion panels 3A and 3B are disposed opposite each other, and the side portion panels 3C and 3D are disposed opposite each other. The side portion panels 3A to 3D are folded at the end of the bottom portion to form the side portion 3 standing upright from the bottom portion 2. One end side of the side portion panel 3A is joined to the side portion panel 3C, and the other end side of the side portion panel 3A is joined to the side portion panel 3D. Similarly, one end of the side panel 3B is joined to the side panel 3C, and the other end of the side panel 3B is joined to the side panel 3D. The side panels can be joined together by heat sealing or hot melt adhesive. Joining by heat sealing is used. A heat seal layer for thermoforming is provided on the inside, outside, or both sides of the paper container 1. In the paper container 1, adjacent side panels are joined together to form the side portion 3 that surrounds the periphery of the bottom portion 2. The method of joining the side panels together is not particularly limited, and the side panels may be joined together by hot melt adhesive.

[0011] The paper container 1 also has a flange portion 4 extending outward from the side portion 3. The flange portion 4 is formed by folding a plurality of flange pieces 4A-4D extending from each of the plurality of side portion panels 3A-3D at fold lines 6 along the outer end portion of the side portion 3, so that the flange portions 4 extend outward from the side portion 3. The flange pieces 4A and 4B are provided at positions corresponding to the long sides of the rectangular bottom portion 2, and the flange pieces 4C and 4D are provided at positions corresponding to the short sides of the rectangular bottom portion 2. More specifically, the flange piece 4A extends from the side portion panel 3A, the flange piece 4B extends from the side portion panel 3B, and the flange piece 4C extends from the side portion panel 3C. Extending from the side panel 3D is a flange piece 4A, and a flange piece 4D extends from the side panel 3D. Also, one end of the flange piece 4A is joined to the flange piece 4C, and the other end of the flange piece 4A is joined to the flange piece 4D. Similarly, one end of the flange piece 4B is joined to the flange piece 4C, and the other end of the flange piece 4B is joined to the flange piece 4D. In this manner, the flange portion 4 that completely surrounds the side panel 3 is formed by joining the adjacent flange pieces together.

[0012] The paper container 1 also has a curled portion 5 provided on the outer end side of the flange portion 4. The curled portion 5 is formed by winding the flange pieces 4A to 4D all around with adjacent flange pieces overlapping at the corners. Therefore, the curled portion 5 is provided all around the paper container 1.

[0013] Here, Fig. 3 is a perspective view of the paper container 1 as seen from the outside. Fig. 3 shows the vicinity of the corner where the side panel 3A and the side panel 3C are connected. The curled portion 5 is formed by rolling the flange pieces 4A to 4D inward on the bottom portion 2 side. The curled portion 5 reinforces the flange portion 4. Furthermore, at the four corners of the paper container 1, adjacent flange pieces are overlapped and rolled, thereby making the curled portion 5 stronger.

[0014] For example, the molded paper container disclosed in the above-mentioned Patent Document 1 is produced by drawing a blank sheet, but the press-formed flange portion is not reinforced in any way. Therefore, there is a problem that the strength of the flange portion decreases when the flange portion becomes soft due to absorption of moisture such as condensation water from the outer end side of the flange portion. Paper containers for food are generally stacked during transportation or when sold at retail stores, and if the strength of the flange portion decreases, there is a risk that the stacked paper containers will collapse or break from the flange portion.

[0015] On the other hand, the paper container 1 according to this embodiment has the outer end side of the flange portion 4 reinforced by the curled portion 5. This makes it difficult for the curled portion 5 to absorb moisture from the outer end side of the flange portion 4, and prevents the flange portion 4 from becoming soggy. Because the strength of the flange portion 4 is improved, the paper container 1 can be suitably used as a container for refrigerated or frozen foods, which are prone to condensation at room temperature. In this way, the paper container 1 according to this embodiment has improved strength.

[0016] Furthermore, in the paper container 1 according to this embodiment, the flange portion 4 is reinforced, so that the flange portion 4 can better withstand a load when another paper container 1 is stacked on top of the flange portion 4. Furthermore, because the curled portion 5 is provided on the outer end side of the flange portion 4, a step is formed by the curled portion 5 on the outer end side of the flange portion 4. This step makes it possible to form a gap between the upper and lower flange portions 4 when multiple paper containers 1 are stacked. For example, multiple paper containers 1 before food is stored are stacked, and in this case, a gap is formed between the upper and lower flange portions 4, making it easier to remove one paper container 1.

[0017] As described above, the paper container 1 according to this embodiment can easily take out one paper container 1 when multiple containers are stacked while achieving an improvement in strength. Furthermore, the paper container 1 can easily attach a lid by providing the curled portion 5. For example, when a lid that fits to the flange portion 4 is used, the lid can be easily opened and closed by fitting the lid to the strong curled portion 5. Furthermore, when a seal-type lid is used, the curled portion 5 prevents the flange portion 4 from becoming soft even if a seal is applied to the flange portion 4, so a suitable sealed state can be maintained.

[0018] As shown in Figs. 1 and 2, the flange portion 4 has a flat portion 40 that is connected to the side portion 3 via a folding line 6 and extends toward the curled portion 5. The flat portion 40 is provided around the entire circumference of the flange portion 4. The paper container 1 has the flat portion 40. , the moment of area becomes larger and the bending rigidity improves, so that the strength in the vertical direction improves. Furthermore, the flat portion 40 of the paper container 1 makes it easy to stack multiple paper containers. Furthermore, when paper containers without curled portions are stacked, the flanges of each paper container are in close contact with each other, making it difficult to remove one paper container. In contrast, when multiple paper containers 1 according to this embodiment are stacked, gaps are generated between the overlapping curled portions 5 because each paper container 1 has a curled portion 5. Because of this gap, the paper containers 1 can be easily removed one by one even when multiple paper containers 1 are stacked. This makes it easy to handle the paper container 1 according to this embodiment using an automatic tray feeder of a food manufacturer.

[0019] 1 and 3, the four corners of the side surface portion 3 are curved. This prevents stress from concentrating on the four corners of the side surface portion 3 of the paper container 1, improving impact resistance.

[0020] 3, the corners of the side portion 3 are formed by overlapping parts of the two side panels such that the side panel 3A extending from the long side of the bottom portion 2 is on the outside and the side panel 3C extending from the short side of the bottom portion 2 is on the inside. Although not shown, the corners of the side portion 3 are also formed by overlapping parts of the two side panels such that the side panels 3A and 3B extending from the long side of the bottom portion 2 are on the outside and the side panels 3C and 3D extending from the short side of the bottom portion 2 are on the inside at the other three corners. Note that the corners of the side portion 3 of the paper container 1 may be formed by overlapping parts of the two side panels such that the side panels 3C and 3D extending from the short side of the bottom portion 2 are on the outside and the side panels 3A and 3B extending from the long side of the bottom portion 2 are on the inside.

[0021] Next, the material of the paper container 1 will be described. The paper container 1 according to this embodiment is produced by assembling blank sheets formed from paper base materials containing pulp. Examples of pulp constituting the paper base material include hardwood kraft pulp such as hardwood unbleached kraft pulp (LUKP) and hardwood bleached kraft pulp (LBKP); softwood kraft pulp such as softwood unbleached kraft pulp (NUKP) and softwood bleached kraft pulp (NBKP); mechanical pulp such as groundwood pulp (GP), pressurized groundwood pulp (PGW), refiner mechanical pulp (RMP), thermomechanical pulp (TMP), chemi-thermomechanical pulp (CTMP), chemi-mechanical pulp (CMP), and chemi-ground pulp (CGP); recycled paper pulp; non-wood fiber pulp such as kenaf, bagasse, bamboo, and cotton; and synthetic pulp. These pulps can be used in a wide range of applications. The polymers may be used alone or in combination of two or more.

[0022] Furthermore, the paper container 1 has a water-resistant resin layer 7 provided at least on the inner surface side of the container. This improves the paper container 1's resistance to moisture. There are no particular limitations on the resin used for the water-resistant resin layer 7. The water-resistant resin is preferably a thermoplastic resin. Specifically, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polylactic acid, and polybutylene succinate, polyvinyl chloride, polyvinylidene chloride, polybutene, polybutadiene, ethylene-vinyl acetate copolymer, polyethylene, polypropylene, and ethylene-propylene copolymer are preferred. Examples of the polymerizable compound include polyolefin resins such as polymethylpentene; polycarbonate; polyurethane; polyamide; polyacrylonitrile; and poly(meth)acrylate.

[0023] Among these, polyethylene, polypropylene, ethylene-propylene copolymer, etc. Preferred are polyolefins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polylactic acid, and polyesters such as polybutylene succinate, more preferred are polyethylene, polypropylene, polyethylene terephthalate, polylactic acid, and polybutylene succinate, and further preferred are polyethylene and polypropylene. Ethylene is even more preferred. In addition to the above materials, biomass resins and biodegradable resins may be used as the resin. These resins may be used alone or in combination of two or more.

[0024] Next, a blank sheet used to create the paper container 1 according to this embodiment will be described. FIG. 4 is a plan view of the blank sheet 100 according to this embodiment, seen from the inside. The blank sheet 100 includes a bottom portion 2 and side panels 3A to 3D extending from the bottom portion 2. The side panel 3A is folded along the end of the bottom portion 2 to form the side portion 3 shown in FIG. 1 and FIG. 2. The blank sheet 100 also includes a plurality of flange pieces 4A to 4D forming the flange portion 4 shown in FIG. 1 and FIG. 2. The flange pieces 4A to 4D are configured as a contiguous part with the side panels 3A to 3D, and are folded along the fold lines 6 to form the flange portion 4. The flange pieces 4A to 4D have a width sufficient to form the flat portion 40 and the curl portion 5 on the tip side thereof shown in FIG. 1 and FIG. 2. The flange pieces 4A to 4D on the tip side of the flat portion 40 are rolled to form the curl portion 5 shown in FIG. 1 to FIG. 3.

[0025] 4, the blank sheet 100 includes a plurality of intermediate panels 8A-8D that connect adjacent side panels together. The intermediate panels 8A-8D are provided between adjacent side panels 3A-3D and connect these side panels together. The blank sheet 100 is folded and the intermediate panels 8A-8D are inserted between the adjacent side panels to produce the paper container 1.

[0026] Further, the intermediate panels 8A-8D have a shape in which the outer end is cut inward with respect to the adjacent side panel 3A-3D. As a result, when the blank sheet 100 rolls the flange pieces 4A-4D to form the curled portion 5, the curled portion 5 can be formed at the four corners where two adjacent flange pieces overlap, without the intermediate panels 8A-8D being included in the curled portion 5. The curled portion 5 becomes stronger as the number of overlapping sheets increases, but it becomes more difficult to roll the sheets and form the curled portion 5. In the blank sheet 100 according to this embodiment, the curled portion 5 can be formed at the corners where two flange pieces overlap, so that the strength at the corners is improved and the curled portion 5 can be formed more easily than in the case where three sheets overlap.

[0027] This application describes a perspective view and six-side views of a paper container 1 according to this embodiment. Fig. 5 is a perspective view of the paper container 1 according to this embodiment, and Figs. 6 to 11 are six-side views of the paper container 1 according to this embodiment. Fig. 6 is a front view, Fig. 7 is a rear view, Fig. 8 is a plan view, Fig. 9 is a bottom view, Fig. 10 is a right side view, and Fig. 11 is a left side view.

[0028] <Other embodiments> Although the embodiments of the present invention have been described above, the above-mentioned various embodiments and modifications can be combined as much as possible. In the above-mentioned embodiments, the bottom surface portion 2 is rectangular, but the shape of the bottom surface portion 2 is not limited to this. The bottom surface portion 2 may be a quadrangular shape such as a square or a rhombus, a polygonal shape such as a hexagonal shape or an octagonal shape, or an elliptical or oblong shape.

[0029] In the above embodiment, the water-resistant resin layer 7 is made of a thermoplastic resin, but the paper container 1 according to this embodiment is not limited to this. For example, the resin layer 7 may be made of a thermosetting resin. [Explanation of symbols]

[0030] 1. Paper container 2...Bottom part 3...Side part 3A,3B,3C,3D...Side panel 4. Flange section 4A, 4B, 4C, 4D Flange pieces 40...Flat area 5. Curl section 6. Fold line 7. Resin layer 8A, 8B, 8C, 8D Middle Panel 100 Blank Sheet

Claims

1. A bottom portion and a side portion in which a plurality of side panels extending from the bottom portion are folded up along an edge of the bottom portion; a flange portion in which a plurality of flange pieces extending from each of the plurality of side panel portions are bent along a folding line along an outer end portion of the side portion; A curl portion is provided on the outer end side of the flange portion and is wound in a state where adjacent flange pieces overlap each other; Equipped with The flange portion has a flat portion connected to the side surface portion via the folding line and extending toward the curled portion. Paper container.

2. The container has a water-resistant resin layer provided on at least the inner surface side of the container. The paper container according to claim 1.

3. The corners of the side surface are curved. The paper container according to claim 1 or 2.

4. The bottom surface portion is rectangular, At least a portion of the two side panels overlap with each other so that the side panel extending from the long side of the bottom portion faces outward and the side panel extending from the short side of the bottom portion faces inward, forming a corner of the side surface. The paper container according to claim 1 or 2.

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