Container made of curled fiber material

Abstract

[Problem] To provide a curled container made of a fiber material, the container being such that sealability can be ensured while maintaining an aesthetic appearance and ease of molding. [Solution] A curled container made of a fiber material comprises: a polygonal bottom panel partitioned by a border; a side wall section formed from a first side surface panel and a second side surface panel respectively continuous with the bottom panel via the border, and inclined so as to expand in an open-fan shape toward an opening edge from the border; and a curled opening part in which an upper end of the side wall section is wound in a curl shape. The side wall section has corner parts where both ends of the first side surface panel and the second side surface panel overlap each other. A missing region is provided in at least one of the end faces of the first side surface panel and the second side surface panel constituting the corner parts, and the end surface of the first side surface panel or the end surface of the second side surface panel constitutes the curled opening part. From among the first and second side surface panels, the panel positioned on the outside at the corner parts is provided with a projection part accommodated in the curled opening part.

Description

Technical Field

[0001] The present invention relates to a container made of a curled fiber material formed from a fiber material such as a paper material.

Background Art

[0002] As containers for storing foods, medical products, etc., shallow dish-shaped trays or boxes having an opening with an open upper surface are widely used. In recent years, from the viewpoints of environmental protection and recycling, containers made of fiber materials mainly composed of paper have been proposed.

[0003] Fiber material containers can be used together with a lid material capable of closing the opening. Therefore, as such fiber material containers, for example, as exemplified in Patent Document 1 and Patent Document 2, a structure having a top curl shape in which the opening edge of the container is curled has also been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] In containers having a conventional structure including the above-mentioned patent documents, there are still points to be improved. That is, by providing a top curl shape as exemplified in the above-mentioned patent documents, the adhesion to the lid and the strength at the opening edge of the container can be improved.

[0006] Generally, when forming the above-mentioned containers, a single blank is folded along the scribed lines to form side walls that are inclined relative to the container's bottom surface (also called the bottom panel). At this time, the curl shape applied to the opening edge of the container is desired not only for sufficient adhesion to the lid, but also for excellent aesthetics and ease of molding at the opening edge.

[0007] In this regard, the method proposed in Patent Document 1 results in numerous wrinkles at the corners of the container, which can be said to detract from the product's aesthetic appeal. On the other hand, the method proposed in Patent Document 2, for example, involves curling the corners, which involves layering two blanks, making it difficult to curl them. This can make container molding difficult, and there is still considerable room for improvement.

[0008] The present invention has been made in view of the above-mentioned problems, and aims to provide a bottomed container made of a fibrous material, mainly made of paper, that can be fitted with a seal lid or a slip lid, and that can maintain aesthetics and ease of molding while also ensuring airtightness. [Means for solving the problem]

[0009] A container made of a curled fiber material in one embodiment of the present invention is (1) a container made of a curled fiber material having an open top surface and a curled opening edge, comprising a polygonal bottom panel demarcated by a score line, a first side panel and a second side panel that are continuous with the bottom panel via the score line, a side wall portion that slopes to widen from the score line to the opening edge, and a curled opening portion in which the upper end of the side wall portion is curled, wherein the side wall portion has a corner portion where both ends of the first side panel and the second side panel overlap, a missing area is provided on at least one of the end faces of the first side panel and the second side panel that constitute the corner portion, and either the end face of the first side panel or the second side panel becomes the curled opening portion, and the panel of the first side panel and the second side panel that is located on the outside at the corner portion has a projection portion that is contained within the curled opening portion Multiple discontinuous segments on the outer edge end face that demarcates the missing region Established The paper material constituting the curled fiber material container has a paper thickness of 225 μm to 555 μm, and a paper density of 0.55 g / cm³. 3 ~0.85g / cm 3 That is, It is characterized by the following:

[0010] Furthermore, in the container made of curled fiber material described in (1) above, (2) the projection at least one of Preferably, it is positioned towards the center of the outer edge end face that demarcates the missing region.

[0012] Also, the above ( 1 In the container made of curled fiber material described in ), 3 ) The width of the projection located in the center of the missing area is Among the missing areas It is preferable that the width is greater than or equal to the width of the projection located on the end side.

[0013] Also, the above (1)~( 3 In a container made of curled fiber material as described in any of the following, 4 The bottom panel is divided by the rectangular grid lines, and the protrusions are provided corresponding to the corner portions located at the four corners of the bottom panel. Furthermore, at least one of the end faces of the first side panel and the second side panel constituting the corner portion has a side overhang that is positioned adjacent to the grid line of the bottom panel and extends outwards to the other end face of the first side panel and the second side panel, and at the corner bottom of the corner portion, the paper material having the paper thickness and paper density is condensed by the side overhang as it moves from the inside to the outside of the container. It is preferable.

[0014] In addition, in the container made of the curled fiber material according to any one of the above (1) to ( 3 ), it is preferable that the height from the outer edge side end surface of the protrusion is set to a size that fits within the missing region. 5

[0015] In addition, in the container made of the curled fiber material according to the above (1), 6 it is preferable that the missing region is provided on either the end surface of the first side panel or the second side panel, and the panel provided with the missing region is positioned outside at the corner portion.

Advantages of the Invention

[0016] According to the container made of the curled fiber material of the present invention, by forming the side wall by sharing between the short side panel and the long side panel, it is possible to secure the sealing property at the side wall portion while achieving both the strength of the curled mouth portion and the ease of molding.

Brief Description of the Drawings

[0017] [Figure 1] It is a perspective view of the container made of the curled fiber material according to the embodiment as seen from obliquely above. [Figure 2] It is a perspective view of the container made of the curled fiber material according to the embodiment as seen from obliquely below. [Figure 3] It is a side view of the container made of the curled fiber material according to the embodiment as seen from the side of the short side panel. [Figure 4] It is a side view of the container made of the curled fiber material according to the embodiment as seen from the side of the long side panel. [Figure 5] It is a schematic view showing the blank of the container made of the curled fiber material according to the embodiment. [Figure 6] It is a schematic view showing an enlarged view of the vicinity of the corner portion of the blank of the container made of the curled fiber material according to the embodiment. [Figure 7]These are schematic diagrams showing the cross-sectional state at predetermined height intervals from the bottom panel at the corner bottom of a container made of curled fiber material according to the embodiment. [Figure 8] These are schematic diagrams showing the cross-sectional state at the corner bottom of a container made of curled fiber material according to the embodiment. [Figure 9] This is a schematic diagram showing the main parts of a container made of curled fiber material according to Modification Example 1. [Figure 10] This is a schematic diagram showing the main parts of a container made of curled fiber material according to Modification 2. [Figure 11] This is a schematic diagram showing the main parts of a container made of curled fiber material according to Modification 3. [Figure 12] This is a schematic diagram showing the main parts of a container made of curled fiber material according to Modification 4. [Modes for carrying out the invention]

[0018] Hereinafter, the container made of curled fiber material according to this embodiment will be described in detail with reference to the drawings as appropriate. The following embodiments describe one example to which the present invention is applied and are not intended to limit the present invention in any way, and may be implemented by appropriately supplementing other known configurations, including the above-mentioned patent documents. For the sake of explanation, in the following, the height direction of the container made of curled fiber material 100 with the bottom panel 10 placed with the opening facing vertically upward will be set as the Z direction, the direction in which the long line RL2 extends will be set as the X direction, and the direction in which the short line RL1 extends will be set as the Y direction.

[0019] [Container made of curled fiber material] The curled fiber material container 100 in this embodiment will be described with reference to Figures 1 to 4 and others. As shown in these figures, the curled fiber material container 100 in this embodiment is, for example, mainly made of paper, and is a curled bottom container with an open top and a curled opening edge OE. Here, "primarily paper-based" refers to a manufacturing method in which the paper is molded using, for example, known paper made of fibrous material, or composite materials based on fibrous material and resin, such as when known resin material (e.g., polyethylene) is coated on the inner or outer surface of the paper.

[0020] The paper thickness of the curled fiber material container 100 is preferably 225 μm to 555 μm, and more preferably 310 μm to 555 μm from the viewpoint of preventing leakage. The paper density of the curled fiber material container 100 is 0.55 g / cm³. 3 ~0.85g / cm 3 The following is preferable, of which 0.55 g / cm³ is preferred. 3 More than 0.70g / cm 3 The following is even more preferable:

[0021] The curled fiber material container 100 may have a base paper having the above-described paper thickness and density, and a known resin material (e.g., LDPE) laminated to the inner surface of the container. Alternatively, the curled fiber material container 100 of this embodiment may have a known resin material laminated to both the inner and outer surfaces of the base paper.

[0022] Furthermore, the curled fiber material container 100 of this embodiment can be covered with a known overlay lid or sheet-like lid on the opening edge OE, for example. As an example, the overlay lid may be a known lid made of heat-resistant OPS (biaxially oriented polystyrene), amorphous polyethylene terephthalate resin, polystyrene, polypropylene, etc. The curled fiber material container 100 can be filled with known contents, such as food containing soup or seasonings.

[0023] More specifically, the curled fiber material container 100 of this embodiment is composed of a bottom panel 10, a side wall portion 20, and a curled opening portion 30, as shown in Figures 1 to 4.

[0024] The bottom panel 10 is a polygonal area demarcated by the grid lines RL. As can be seen from Figures 1 and 2, the bottom panel 10 in this embodiment is preferably rectangular in shape, for example, having a pair of short grid lines RL1 and a pair of long grid lines RL2. That is, the bottom panel 10 in this embodiment may be demarcated by rectangular grid lines RL.

[0025] In this embodiment, a rectangular bottom panel 10 is shown as an example, but the present invention is not limited to this form. Insofar as it is covered by a cover such as the above-mentioned overlapping lid or sheet-like lid, it may be any polygon other than a rectangle, such as a triangular or pentagonal shape, in addition to a horizontally elongated octagonal shape with chamfered corners.

[0026] The side wall portion 20 is composed of a first side panel 21 (short side panel in this example) and a second side panel 22 (long side panel in this example) which are continuous with the bottom panel 10 via the aforementioned grid line RL. As shown in Figure 3 and other figures, the first side panel 21 and the second side panel 22 are configured to be bent from the bottom panel 10 via the grid lines to give them an inclination. In this example, since the bottom panel 10 is rectangular, the first side panel 21 and the second side panel 22 are panels that protrude from the bottom panel 10 so as to be perpendicular to each other when blank. The first side panel 21 and the second side panel 22 may have the same width (length in the direction parallel to their respective grid lines) and height (corresponding to H1 and H2 in Figure 6), or one of them may be wider than the other. As described above, in the following description, the first side panel 21 will be described as a short side panel with a relatively narrower width than the second side panel 22, while the second side panel will be described as a long side panel with a relatively wider width. More specifically, in this embodiment, the short side panel 21 is connected to the bottom panel 10 with the aforementioned short ruled line RL1, which serves as the first ruled line, as the boundary, as shown in Figure 3. Also, in this embodiment, the long side panel 22 is connected to the bottom panel 10 with the aforementioned long ruled line RL2, which serves as the second ruled line, as the boundary, as shown in Figure 4.

[0027] Thus, the grid line RL of this embodiment is composed of a short grid line RL1 that separates the bottom panel 10 and the short side panel 21, and a long grid line RL2 that separates the bottom panel 10 and the long side panel 22. As can be seen from Figures 5 and 6, the height H1 of the short side panel 21 (the size from the short grid line RL1 to the outer end face ES1) and the height H2 of the long side panel 22 (the length from the long grid line RL2 to the outer end face ES2) may be defined to be approximately the same size.

[0028] Furthermore, as can be seen from Figure 1 and other figures, the side wall portion 20 of this embodiment is inclined to expand outwards from the aforementioned grid line RL to the opening edge OE and is connected to the bottom panel 10. In other words, in the curled fiber material container 100 of this embodiment, the opening area at the opening edge OE and the area of ​​the lid are larger than the area of ​​the bottom panel 10.

[0029] <Side protrusion corresponding to the corner bottom> As can be seen from Figures 1, 2, and 5, the side wall portion 20 has a corner portion 23 where both ends of the short side panel 21 and the long side panel 22 overlap. A side overhang portion 24 is formed on at least one of the end faces of the short side panel 21 and the long side panel that constitute the corner portion 23, positioned adjacent to the grid line RL of the bottom panel 10 (i.e., adjacent to the intersection IP of the short grid line RL1 and the long grid line RL2) and extending outwards to the other end face of the short side panel 21 and the long side panel 22.

[0030] In this embodiment, the container 100 made of curled fiber material is provided with the side protrusions 24 adjacent to the intersection IP, so that when the container is assembled from the blank BK (see Figure 5), the paper material is condensed at the corner bottoms 23b located at the four corners of the container, thereby preventing gaps from forming at the corner bottoms 23b and leakage of contents when the container is in use.

[0031] It is preferable that the above-mentioned side protrusions 24 are provided corresponding to each corner bottom 23b of the corner portion 23 of the curled fiber material container 100. Since the bottom panel 10 of the curled fiber material container 100 is rectangular, the side protrusions 24 in this embodiment are provided at the corner portions 23 located at the four corners of the bottom panel 10. In other words, if the bottom panel 10 is a polygonal shape other than a rectangle, the side protrusions 24 will be provided in a number other than four, corresponding to each corner.

[0032] As shown in Figures 1, 2, and 6, the side projection 24 of this embodiment is formed on the end portion 22e of the long side panel 22, and the side projection 24 overlaps with the outer surface of the short side panel 21 and is fixed in place via a known adhesive or the like. More specifically, as shown in Figure 6, the side projection 24 of this embodiment is a triangular portion including a base point 24a that substantially coincides with the intersection IP, a vertex 24b that becomes a branching point that separates from the short side panel 21 when blank, and the outermost end point 24c of the end portion 22e of the long side panel 22 that is furthest from the intersection IP.

[0033] The present invention is not limited to this embodiment, and as will be described later, the side overhang 24 may be formed at the end 21e of the short side panel 21, and the side overhang 24 may be fixed to overlap with the outer surface of the long side panel 22.

[0034] As can also be seen from the figure, the side wall portion 20 does not have a crease line RL, and at the corner portion 23, at least a part of the short side panel 21 and the long side panel 22 are fixed together with a known adhesive so as to overlap each other. In other words, in the container 100 made of curled fiber material of this embodiment, the absence of a crease line RL on the side wall portion 20 results in a good appearance, and furthermore, wrinkles are less likely to form on the inner side, making it possible to suppress leakage of contents due to capillary action caused by such wrinkles. Furthermore, in this embodiment, since the aforementioned grid line RL is not provided on the side wall portion 20, the degree of inclination of the side wall portion 20 relative to the bottom panel 10 can be set to any angle by adjusting the overlap between the short side panel 21 and the long side panel 22. For example, if the overlap between the short side panel 21 and the long side panel 22 is increased, the degree of inclination of the side wall portion 20 relative to the bottom panel 10 increases, resulting in a steep slope where the side wall rises from the bottom surface. Conversely, if this overlap is reduced, the degree of inclination decreases, resulting in a gentle slope where the side wall rises.

[0035] The curled mouth portion 30 is formed by curling the upper ends of the aforementioned side wall portions (short side panel 21 and long side panel 22). The specific shape of the curled mouth portion 30 is not particularly limited as long as it is possible to form a top curl; for example, known top curl shapes exemplified in Japanese Patent Application Publication No. 2022-82965 can be applied. Such a curled mouth portion 30 can be formed using a known molding machine capable of forming a curled mouth portion of a container.

[0036] <Reinforcement and improved moldability at the curled end> In the curled mouth portion 30, as shown in Figures 5 and 6, a missing region MA is provided on either the end face (outer edge end face) of the short side panel 21 or the long side panel 22 that constitute the corner portion 23, and the other end face of the short side panel 21 or the long side panel 22 that corresponds to this missing region MA (i.e., overlaps with the missing region during molding) forms the curled mouth portion 30. In this embodiment, the missing area MA is provided on either the short side panel 21 or the long side panel 22, but it is also possible to provide missing area MA on both the short side panel 21 and the long side panel 22 such that one complements the missing area MA of the other. In other words, in this embodiment, it is sufficient that the missing area MA is provided on at least one of the end faces of the short side panel 21 and the long side panel 22 that constitute the corner portion 23, and that either the end face of the short side panel 21 or the long side panel 22 forms a curled opening portion 30. Furthermore, if the missing area MA is provided on either the short side panel 21 or the long side panel 22, it is preferable that the panel on which the missing area MA is provided (the long side panel 22 in this example) is located on the outside (outer surface) of the container in the corner portion 23, from the viewpoint of the appearance of the container and the penetration of contents through the end face.

[0037] The missing region MA is defined as the region formed at the upper end of the side wall portion 20 where the end regions of the short side panel 21 and the long side panel 22 overlap radially during molding from the blank BK into a container, as illustrated in Figure 6, etc., to form the curled mouth portion 30 described above.

[0038] The extent to which the ends of the short side panel 21 and the long side panel 22 are stacked radially at the corner portion 23 (for example, the stacking region 21x of the short side panel 21 is shown in Figure 6) can be appropriately defined according to, for example, the degree of inclination of the side wall portion 20 relative to the bottom panel 10, or the size of the buffer 21y that extends beyond the missing region MA to prevent a step from occurring in the curled opening portion 30.

[0039] More specifically, in the curled mouth portion 30 of this embodiment, the above-mentioned missing region MA is provided at the end 22e of the long side panel 22 that constitutes the corner portion 23, and the upper end of the short side panel 21 corresponding to the portion overlapping with this missing region MA is configured to become the curled mouth portion 30. In the curled fiber material container 100 of this embodiment, by providing the above-mentioned curled mouth portion 30 at the corner portion 23, it is possible to form the curled mouth portion 30 in a more stable shape without requiring excessive load during molding from the blank BK to the container.

[0040] Furthermore, as shown in Figures 5 and 6, in the curled fiber material container 100 of this embodiment, it is preferable that the outer edge end face ES3 of the short side panel 21 and long side panel 22 on the side with the missing region MA is provided with a projection PP that is enclosed in the curled mouth portion 30 during molding. In this case, it is preferable that the projection PP is located near the center MAc of the missing region MA. Also, it is preferable that the height H3 (see Figure 6) of the projection PP from the outer edge end face ES3 is set to a size that fits within the missing region MA. Thus, the projection PP of this embodiment may be located towards the center of the outer edge end face ES3 that demarcates the missing region MA. This appropriately increases the strength of the curled mouth portion 30 while maintaining ease of molding, thereby ensuring durability that can withstand repeated attachment and detachment by the lid portion, for example. Furthermore, by providing the projection PP enclosed within the curled opening 30 as described above, it becomes possible to ensure the thickness of the curled opening 30, especially at the corner 23. That is, at the corner 23, tensile forces can occur on both the long and short sides of the curled opening 30, making the central part particularly prone to becoming thinner (the diameter of the curl smaller). In contrast, as in this embodiment, by having the projection PP inside the curled opening 30 at the corner 23, the projection PP can prevent the curl from becoming smaller in diameter.

[0041] Figure 7 shows the cross-sectional state at predetermined height intervals from the bottom panel 10 at the corner bottom 23b of the curled fiber material container 100 according to the embodiment. As can be seen from the figure, at the corner portion 23, the cross section near the corner bottom 23b is cut at EE, and the cross sections cut upward in the Z direction from this cross section EE at predetermined height intervals are shown as DD, CC, BB, and AA.

[0042] For example, in section AA located at approximately the midpoint of the corner section 23, it can be seen that the area including the end 21e of the short side panel 21 and the area including the end 22e of the long side panel 22 overlap. In this embodiment, since the blank BK shown in Figure 5 is used, the area where the short side panel 21 and the long side panel 22 overlap gradually decreases as you move downward from section AA.

[0043] On the other hand, in the cross-section EE showing the area near the corner bottom 23b, it can be seen that the paper material is condensed near the corner bottom 23b due to the action of the aforementioned side protrusion 24, thereby suppressing the generation of pores and other defects.

[0044] Furthermore, Figure 8 shows the state of several cross-sections from the inside to the outside at the corner bottom 23b of the curled fiber material container 100 according to the embodiment. As can be seen from Figure 8, in the inner cross-section ii near the corner bottom 23b where the contents are stored, the degree of aggregation of the paper material is not very strong and pores are formed.

[0045] On the other hand, in the MM section, which is shifted outward from the ii section, the width of the pores described above is significantly narrower, and in the OO section, which is located further outward, it can be seen that the pores are completely closed.

[0046] As described above, in the container 100 made of curled fiber material of this embodiment, the upper end of either the short side panel 21 or the long side panel 22 that constitute the corner portion 23 becomes the curled opening portion 30 during molding, and the upper end of the other corresponding portion of the curled opening portion 30 is provided with the aforementioned missing region MA and projection PP. This makes it possible to improve the moldability of the curled shape while reinforcing the curled opening portion 30 with the projection PP.

[0047] The embodiments described above are examples that embody the spirit of the present invention, and may be modified as appropriate without departing from the spirit of the present invention. Furthermore, known structures and methods may be added and modified as appropriate without departing from the spirit of the present invention.

[0048] The following describes preferred modifications of this embodiment. In the various modifications described below, configurations that have the same functions and operations as those described in the above-described embodiment are given the same reference numerals, and their descriptions are omitted as appropriate.

[0049] <Example 1> Figure 9 shows a container 110 made of curled fiber material according to Modification 1. In the container 100 made of curled fiber material according to the above embodiment, the side protrusion 24 was provided at the end 22e of the long side panel 22. In contrast, in the container 110 made of curled fiber material according to Modification 1, the side protrusion 24 is provided at the end 21e of the short side panel 21.

[0050] More specifically, as shown in Figure 9, the side projection 24 in the modified example 1 is a triangular portion that includes a base point 24a which is approximately coincident with the intersection IP described above, a vertex 24b which is a branching point that separates from the long side panel 22 when blank, and the outermost endpoint 24c of the end 21e of the short side panel 21 that is furthest from the intersection IP. In the container 110 made of curled fiber material according to the modified example 1 described above, it is possible to enjoy the same effects as those shown in the above embodiment.

[0051] <Modification 2> Figure 10 shows a container 120 made of curled fiber material according to Modification 2. In the above-described containers 100 and 110 made of curled fiber material, the side overhang 24 was formed on either the short side panel 21 or the long side panel 22. In contrast, in the container 120 made of curled fiber material according to Modification 2, the side overhang 24 is provided extending across both the end 21e of the short side panel 21 and the end 22e of the long side panel 22.

[0052] More specifically, as shown in Figure 10, the side projection 24 in the modified example 2 has a base point 24a that is approximately the same as the intersection IP described above, vertices 24s and 24t which are branching points that are separated from the long side panel 22 when blank, and two symmetrical triangular portions that include two outer endpoints 24c (the outer endpoint of the end 21e of the short side panel 21 that is furthest from the intersection IP, and the outer endpoint of the end 22e of the long side panel 22 that is furthest from the intersection IP).

[0053] Thus, the side projection 24 in the present invention only needs to be provided at least one of the end 21e of the short side panel 21 and the end 22e of the long side panel 22. The container 120 made of curled fiber material according to the modified example 2 described above can also enjoy the same effects as those shown in the above embodiment and modified example 1. The two triangular shapes that constitute the side projection 24 in modified example 2 may be the same shape as the other so as to be symmetrical, or they may be different shapes.

[0054] <Variation 3> Figure 11(a) shows a container 130 made of curled fiber material according to Modification 3. In the curled fiber material containers according to the above-described embodiment, Modification 1 and Modification 2, the base point 24a of the side projection 24 was positioned so as to substantially coincide with the intersection IP. In contrast, in the curled fiber material container 130 according to Modification 3, the base point 24a is positioned in close proximity to the intersection IP of the short line RL1 and the long line RL2, rather than coinciding with it.

[0055] More specifically, as shown in Figure 11(b), in Modification 3, the long line RL2 has an extension line RLL that extends from the intersection IP with the short line RL1 at the corner portion 23. The base point 24a of the side projection portion 24 in Modification 3 is positioned to start from the end of this extension line RLL.

[0056] Thus, in the present invention, the base point 24a of the side projection 24 does not necessarily have to coincide with the intersection IP, and the base point 24a may be positioned close to the intersection IP, as in this modified example 3. In modified example 3, the long ruled line RL2 had an extension line RLL, but instead of this embodiment, the short ruled line RL1 may have an extension line RLL. In the container 130 made of curled fiber material according to the modified example 3 described above, it is possible to enjoy the same effects as those shown in the above-described embodiment.

[0057] <Modification 4> Figure 12 shows a container 140 made of curled fiber material according to Modification 4. In the curled fiber material container 100 according to the above embodiment, a single projection PP was located near the center MAc on the outer edge end face ES3 of the side with the missing region MA among the short side panel 21 and the long side panel 22. In contrast, in the curled fiber material container 140 according to Modification 4, multiple projections PP are formed on the outer edge end face ES3 within the missing region MA.

[0058] More specifically, the projection PP in the modified example 4 is composed of a first projection PP1 and a second projection PP2 which is the same width as or narrower than the first projection PP1. The first projection PP1 has the first width W1 described above and is positioned on the outer edge end face ES3 near the center MAc of the missing region MA. On the other hand, the second projection PP2 has a second width W2 which is less than or equal to the first width W1 and is positioned on the outer edge end face ES3 separated from the first projection PP1 by a predetermined gap on the end MAe side of the missing region MA. Thus, the width W1 of the projection located in the center MAc of the missing region MA (first projection PP1) may be set to be greater than or equal to the width W2 of the projection located on the end MAe side (second projection PP2).

[0059] As also shown in the figure, multiple second protrusions PP2 may be arranged on the outer edge end face ES3 within the missing region MA, sandwiching the first protrusion PP1. When multiple second protrusions PP2 are arranged, the widths W2 of the multiple second protrusions PP2 may be the same, or they may have different widths. Furthermore, although the first projection PP1 is shown as a single form in the illustration, multiple projections PP1 may be arranged on the outer edge end face ES3 within the missing region MA, similar to the second projection PP2. When multiple first projections PP1 are arranged, from the viewpoint of reinforcing the curled opening 30, the multiple first projections PP1 may have the same width or different widths, as long as their width is greater than or equal to the width W2 of the second projection PP2.

[0060] Thus, multiple protrusions PP may be intermittently arranged from the central MAc toward the end MAe of the missing region MA. In the curled fiber material container 140 according to the modified example 4 described above, in addition to enjoying the same effects as shown in the above embodiment, the strength of the curled mouth portion 30 can be further increased while maintaining the ease of molding into a curled shape. [Industrial applicability]

[0061] This invention can be used, for example, to manufacture a curled-bottom container that is primarily made of paper and can ensure even sealing even if the bottom surface (bottom panel) has a polygonal shape. [Explanation of symbols]

[0062] 100-140 Curly Fiber Material Containers 10 Bottom panel 20 Side wall section 21 Short side panel 22 Long side panels 23 Corner section 24 Side overhang 30 Curly opening

Claims

1. A container made of curled fiber material, having an open top surface and a curled opening edge, A polygonal bottom panel divided by grid lines, It is composed of a first side panel and a second side panel that are continuous with the bottom panel via the aforementioned grid lines, and has a side wall portion that is inclined to widen towards the opening edge from the grid lines, The upper end of the side wall portion is curled up to form a curled opening portion, The side wall portion has a corner portion where both ends of the first side panel and the second side panel overlap. A missing area is provided on at least one of the end faces of the first side panel and the second side panel that constitute the corner portion, and either the end face of the first side panel or the second side panel becomes the curled opening portion. The first side panel and the second side panel, the panel positioned on the outside at the corner portion, have multiple projections intermittently provided on the outer edge end face that demarcates the missing area, with the projections contained within the curled opening portion. A container made of curled fiber material, characterized in that the paper material constituting the curled fiber material container has a paper thickness of 225 μm to 555 μm and a paper density of 0.55 g / cm³ to 0.85 g / cm³.

2. The container made of curled fiber material according to claim 1, wherein at least one of the protrusions is positioned toward the center of the outer edge end face that demarcates the missing area.

3. The container made of curled fiber material according to claim 1, wherein the width of the projection located in the center of the missing region is greater than or equal to the width of the projection located on the edge side of the missing region.

4. The bottom panel is divided by the rectangular grid lines, The aforementioned protrusions are provided corresponding to the corner portions located at the four corners of the bottom panel. At least one of the end faces of the first side panel and the second side panel constituting the corner portion has a side overhang that is positioned adjacent to the grid line of the bottom panel and extends outwards to the other end face of the first side panel and the second side panel. A container made of curled fiber material according to any one of claims 1 to 3, wherein at the corner bottom of the corner portion, the paper material having the paper thickness and paper density is condensed by the side protrusion as it moves from the inside to the outside of the container.

5. The height of the projection from the outer edge end face is set to a size that fits within the missing area, as described in any one of claims 1 to 3.

6. The container made of curled fiber material according to claim 1, wherein the missing area is provided on either the end face of the first side panel or the second side panel, and the panel on which the missing area is provided is positioned outward at the corner.

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