Rolled rim container made of fibrous material

Abstract

[Problem] To provide a bottomed, rolled rim container made of fibrous material to which, for example, a covering lid can be mounted, and which has an opening and is mainly made of paper, the rolled rim container made of fibrous material being capable of securing uniform sealing performance even if the outer shape of the container is polygonal. [Solution] A rolled rim container made of fibrous material, including: a bottom panel having a polygonal shape and defined by ruled lines; a side wall part inclined in a spreading manner and constituted from first side panels and second side panels that are continuous from the bottom panel with the ruled lines therebetween; and a rolled rim opening part in which the upper end of the side wall part wraps around in a rolled configuration, wherein the side wall part has corner parts where respective ends of a first side panel and a corresponding second side panel overlap, and at least one of the end surfaces of the first side panel and the second side panel constituting a corner part has formed therein a side extension part that is disposed adjacent to the ruled line of the bottom panel and that extends over the other of the end surfaces of the first side panel and the second side panel.

Description

Curled fiber container

[0001] The present invention relates to a curled fibrous container formed from a fibrous material, such as paper.

[0002] For example, shallow dish-shaped trays and boxes are widely used as containers for storing food, medical supplies, etc. In recent years, from the viewpoint of environmental protection and recycling, fibrous containers made of fibrous materials, mainly paper, have been proposed.

[0003] On the other hand, the above-mentioned fibrous material containers may contain foods containing liquid seasonings such as soups and sauces, and ensuring airtightness more reliably is an important factor in increasing the competitiveness of the product. For example, Patent Document 1 proposes a tray-shaped container having a bottom and side walls rising from the bottom, in which a paper substrate is used and a plastic film is laminated and bonded to the paper substrate on the inner and outer surfaces of the bottom and side walls by a forming method using vacuum forming or a combination of vacuum forming and pressure forming.

[0004] Japanese Patent Application Laid-Open No. 2001-114261

[0005] Conventional containers, including those described in the above-mentioned patent documents, still have the following points that need to be improved: As proposed in Patent Document 1, laminating plastic films on both the inner and outer surfaces of the container can certainly ensure airtightness for a certain range of contents.

[0006] However, when storing liquid or semi-liquid contents such as soup or seasoning in a container, it is desirable to be able to prevent leakage from the bottom of the container without vacuum-pressure molding a plastic film as disclosed in the above-mentioned patent documents onto the paper base material of a tray-shaped paper container.

[0007] The present invention has been made in consideration of the above-mentioned problems as an example, and aims to provide a curled fiber material container that can ensure uniform sealing even when the container has a rectangular outer shape, for example, a bottomed fiber material container that is mainly made of paper and can be fitted with a sealing lid or a cover lid.

[0008] A curled fiber material container in one embodiment of the present invention is characterized in that (1) it is a curled fiber material container whose top surface is open and whose opening edge is curled, and which is composed of a polygonal bottom panel defined by a line, and a first side panel and a second side panel each continuous with the bottom panel via the line, and which includes a side wall portion that is inclined so as to expand in a fan-shaped manner from the line to the opening edge, and a curled mouth portion where the upper end of the side wall portion is rolled up in a curled shape, and the side wall portion has a corner portion where both ends of the first side panel and the second side panel overlap, and at least one of the end surfaces of the first side panel and the second side panel that constitute the corner portion is formed with a side extension portion that is positioned adjacent to the line of the bottom panel and extends to the other of the end surfaces of the first side panel and the second side panel.

[0009] In the curled fiber material container described above in (1), (2) the thickness of the bottom panel and the side wall portion is 225 μm to 555 μm, and the paper density is 0.55 g / cm ３ ~0.85g / cm ３ It is preferable that:

[0010] Furthermore, in the curled fiber material container described in (1) above, it is preferable that (3) the bottom panel is divided by the rectangular lines, and the side protrusions are provided at the corner portions located at the four corners of the bottom panel.

[0011] Furthermore, in the curled fiber material container described in any of (1) to (3) above, (4) it is preferable that the side protrusion is formed on the end surface of the panel located on the outer side of the first side panel and the second side panel at the corner portion, and that the side protrusion is fixed to the outer surface of the panel located on the inner side of the corner portion of the first side panel and the second side panel.

[0012] Furthermore, in the curled fiber material container described in (4) above, (5) it is preferable that no lines are provided on the side wall portion and that at least a portion of the first side panel and the second side panel are fixed to each other so as to overlap each other at the corner portion.

[0013] Furthermore, in the curled fiber material container described in (4) above, (6) it is preferable that one of the end faces of the first side panel and the second side panel that have the side protrusion portion and form the corner portion has a missing area, and the outer edge side end face on the side that has the missing area has a protrusion that is contained within the curled mouth portion, and that the other of the first side panel and the second side panel that corresponds to the missing area becomes the curled mouth portion.

[0014] Furthermore, in the curled fiber material container described in (4) above, (7) it is preferable that the lines include a first line that separates the bottom panel from the first side panel and a second line that separates the bottom panel from the second side panel, and that the second line has an extension line extending from the intersection with the first line at the corner portion, and that the side protrusion portion is positioned based on the end of the extension line.

[0015] According to the curled fiber material container of the present invention, the opening edge is curled, thereby improving the sealing performance with the sealing lid, and the formation of a side protrusion on at least one of the end faces of the short side panel and the long side panel also makes it possible to improve the sealing performance at the corners.

[0016] 1 is a perspective view of a curled fiber material container according to an embodiment, viewed from diagonally above; FIG. 2 is a perspective view of a curled fiber material container according to an embodiment, viewed from diagonally below; FIG. 3 is a side view of a curled fiber material container according to an embodiment, viewed from the side of a short side panel; FIG. 4 is a side view of a curled fiber material container according to an embodiment, viewed from the side of a long side panel; FIG. 5 is a schematic view of a blank of a curled fiber material container according to an embodiment; FIG. 6 is a schematic view of an enlarged view of the vicinity of a corner portion of a blank of a curled fiber material container according to an embodiment; FIG. 7 is a schematic view of cross-sectional states at predetermined heights from the bottom panel at a corner bottom of a curled fiber material container according to an embodiment; FIG. 8 is a schematic view of cross-sectional states at a corner bottom of a curled fiber material container according to an embodiment; FIG. 9 is a schematic view of a main part of a curled fiber material container according to a first modification; FIG. 10 is a schematic view of a main part of a curled fiber material container according to a second modification; FIG. 11 is a schematic view of a main part of a curled fiber material container according to a third modification; FIG. 12 is a schematic view of a main part of a curled fiber material container according to a fourth modification.

[0017] Hereinafter, the curled fiber material container according to this embodiment will be specifically described with reference to the drawings as appropriate. Note that the following embodiment describes one example to which the present invention is applied, and does not unintentionally limit the present invention, and may be implemented by appropriately supplementing other known configurations including those described in the above-mentioned patent documents. For the sake of convenience of description, the height direction of the curled fiber material container 100 in a state in which the bottom panel 10 is placed with the opening facing vertically upward is referred to as the Z direction, and the long ruled line RL is referred to as the ２ The direction in which the line extends is called the X direction, and the short ruled line RL １ The direction in which each of the arrows extends is set as the Y direction.

[0018] [Curled Fiber Material Container] A curled fiber material container 100 according to this embodiment will be described with reference to Figures 1 to 4. As shown in these figures, the curled fiber material container 100 according to this embodiment is a bottomed container made primarily of, for example, paper, with an open top and a curled opening edge OE. Here, "mainly made of paper" refers to a manufacturing form in which the container is molded using, for example, known paper made of a fiber material, or a composite material containing a fiber-based resin, such as paper coated on the inner or outer surfaces with a known resin material (e.g., polyethylene).

[0019] The paper thickness of the curled fibrous material container 100 is preferably 225 μm to 555 μm, and more preferably 310 μm or more and 555 μm or less from the viewpoint of preventing leakage. The paper density of the curled fibrous material container 100 is 0.55 g / cm ３ ~0.85g / cm ３ is preferable, and 0.55 g / cm ３ 0.70g / cm or more ３ It is more preferable that:

[0020] The curled fibrous material container 100 may be formed by laminating a known resin material (such as LDPE) on the inside of the base paper having the above-mentioned thickness and density, which will become the inner surface of the container. Also, the curled fibrous material container 100 of this embodiment may be formed in such a way that a known resin material is laminated on both the inner and outer surfaces of the base paper.

[0021] The opening edge OE of the curled fiber material container 100 of this embodiment can be covered with a known flap or sheet-like lid. For example, the flap may be a known lid made of heat-resistant OPS (biaxially oriented polystyrene), amorphous polyethylene terephthalate resin, polystyrene, polypropylene, or the like. The curled fiber material container 100 can be filled with known contents, such as soup or food containing seasonings.

[0022] More specifically, the curled fiber material container 100 of this embodiment includes a bottom panel 10, a side wall portion 20, and a curled opening portion 30, as shown in FIGS.

[0023] The bottom panel 10 is a polygonal portion defined by ruled lines RL. As can be seen from FIGS. 1 and 2, the bottom panel 10 of the present embodiment is, for example, a pair of short ruled lines RL. １ and a pair of long ruled lines RL ２ That is, the bottom panel 10 of this embodiment may be divided by rectangular ruled lines RL.

[0024] Although a rectangular bottom panel 10 is exemplified in this embodiment, the present invention is not limited to this form, and as long as it is covered by a lid body such as the above-mentioned cover lid or sheet-like lid, it may have various polygonal shapes other than a rectangle, such as a horizontally elongated octagonal shape with chamfered corners, a triangular shape, or a pentagonal shape.

[0025] The side wall portion 20 is composed of a first side panel 21 (in this example, a short side panel) and a second side panel 22 (in this example, a long side panel), each of which is continuous with the bottom panel 10 via the aforementioned crease line RL. As shown in FIG. 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 along the crease line to impart an inclination to each other. 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 intersect perpendicularly with each other when blank. The first side panel 21 and the second side panel 22 may have the same width (length in a direction parallel to the respective crease lines) and height (corresponding to H1 and H2 in FIG. 6 ), or one of the widths may be wider than the other. As described above, the following description will be given assuming that the first side panel 21 is a short side panel that is relatively narrower than the second side panel 22, and the second side panel is a long side panel that is relatively wider.

[0026] More specifically, in the short side panel 21 of this embodiment, as shown in FIG. 3, the short crease RL is formed as the first crease. １4, the long side panel 22 in this embodiment is connected to the bottom panel 10 at the boundary of the long crease line RL. ２ The bottom panel 10 is connected to the bottom panel 10 at the boundary.

[0027] In this way, the crease RL of this embodiment is the short crease RL that separates the bottom panel 10 and the short side panel 21. １ and the long crease RL that separates the bottom panel 10 and the long side panel 22. ２ 5 and 6, the height H1 of the short side panel 21 (the short ruled line RL １ From the outer end surface ES １ The height H2 of the long side panel 22 (the length of the long ruled line RL) ２ and outer end surface ES ２ The length from the center to the center of the periphery ...

[0028] 1 and the like, the side wall portion 20 of this embodiment is inclined so as to expand in a fan-like manner from the crease line RL toward 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 extension portion 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. At least one of the end faces of the short side panel 21 and the long side panel that constitute the corner portion 23 is disposed adjacent to the crease line RL of the bottom panel 10 (i.e., the short crease line RL １ and long ruled line RL ２ A side extension 24 is formed on the other end surface of the short side panel 21 and the long side panel 22, adjacent to the intersection IP of the short side panel 21 and the long side panel 22.

[0030] The curled fiber material container 100 of this embodiment is provided with this side protrusion 24 adjacent to the intersection IP, so that when assembling the container from the blank BK (see Figure 5), the paper material (fiber) 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 when the container is in use, which could cause the contents to leak.

[0031] The side projections 24 are preferably provided corresponding to the corner bottoms 23b of the corner portions 23 of the curled fiber material container 100. Since the bottom panel 10 of the curled fiber material container 100 of this embodiment is rectangular, the side projections 24 of 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 has a polygonal shape other than a rectangle, the side projections 24 will be provided in a number other than four to correspond to the corners.

[0032] 1, 2, 6, etc., the side projection 24 of this embodiment is formed on the end 22e of the long side panel 22, and the side projection 24 overlaps the outer surface of the short side panel 21 and is fixed thereto using a known adhesive or the like. More specifically, as shown in Fig. 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 serves as a branch point separating from the short side panel 21 when blank, and an outer end point 24c of the end 22e of the long side panel 22 that is the farthest from the intersection IP.

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

[0034] As can be seen from the figure, the side wall 20 does not have any crease lines RL that would serve as folds, and at the corners 23, the short side panel 21 and the long side panel 22 are at least partially overlapping and bonded together with a known adhesive. In other words, the curled fiber material container 100 of this embodiment has a good appearance because the side wall 20 does not have any crease lines RL that would serve as folds. Furthermore, since the container is less likely to wrinkle on the inside, leakage of contents due to capillary action caused by wrinkles can be suppressed. Furthermore, in this embodiment, the absence of the crease lines RL on the side wall 20 allows the inclination of the side wall 20 relative to the bottom panel 10 to be set at any angle by adjusting the overlap between the short side panel 21 and the long side panel 22. For example, if the short side panel 21 and the long side panel 22 overlap more, the degree of inclination of the side wall portion 20 relative to the bottom panel 10 increases, and the side wall becomes a steep slope rising from the bottom surface, while if this overlap is reduced, the degree of inclination decreases, and the side wall becomes a gentle slope.

[0035] The curled mouth portion 30 is formed by curling the upper ends of the side wall portions (the short side panel 21 and the long side panel 22). The specific shape of the curled mouth portion 30 is not particularly limited as long as it can form a top curl, and known top curl shapes such as those exemplified in JP 2022-82965 A can be applied. Such curled mouth portion 30 can be formed using a known forming machine capable of forming the mouth of a container into a curled shape.

[0036] <Reinforcement and Formability Improvement of Curled Mouth Portion> In the curled mouth portion 30, as shown in Figures 5 and 6, a missing region MA is provided in one of the end faces (outer edge end faces) of the short side panel 21 or the long side panel 22 that constitute the corner portion 23, and the other of the end faces 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 region MA is provided in one of the short side panel 21 or the long side panel 22, but it is also possible to provide missing regions MA in both the short side panel 21 and the long side panel 22, with one panel complementing the other's missing region MA. In other words, in this embodiment, it is sufficient that a missing region MA is provided in at least one of the end faces of the short side panel 21 or the long side panel 22 that constitute the corner portion 23, and that one of the end faces of the short side panel 21 or the long side panel 22 forms the curled mouth portion 30. Furthermore, when a missing area MA is provided in either the short side panel 21 or the long side panel 22, it is preferable that the panel in which the missing area MA is provided (in this example, the long side panel 22) be positioned on the outside (outer surface) of the container at the corner portion 23, from the standpoint of the appearance of the container and the penetration of the contents into the edge surfaces.

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

[0038] The degree to which the ends of the short side panel 21 and the long side panel 22 are radially stacked at the corner portion 23 (as an example, Figure 6 illustrates the stacked area 21x of the short side panel 21) can be appropriately determined depending on, for example, the degree of inclination of the side wall portion 20 relative to the bottom panel 10 and the size of the buffer 21y that extends beyond the missing area MA to prevent a step from occurring in the curled mouth portion 30.

[0039] More specifically, in the curled mouth portion 30 of this embodiment, the aforementioned missing area 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 that corresponds to the portion overlapping with this missing area MA is configured to become the curled mouth portion 30. In the curled fiber material container 100 of this embodiment, by providing the aforementioned 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 when molding the blank BK into a container.

[0040] 5 and 6, in the curled fiber material container 100 of this embodiment, the outer edge side end surface ES of the short side panel 21 and the long side panel 22 on the side having the missing area MA is ３ It is preferable that the protrusion PP is provided on the outer edge side of the missing area MA, and the protrusion PP is included in the curled opening 30 during the molding process. In this case, the protrusion PP is preferably disposed near the center MAc of the missing area MA. ３ The height H3 (see FIG. 6) from the outer edge side end surface ES that defines the missing area MA is preferably set to a size that fits within the missing area MA. ３ The protrusions PP may be positioned toward the center of the curled mouth portion 30. 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 using a lid, for example. Furthermore, by providing the protrusions PP contained within the curled mouth portion 30 as described above, it is possible to ensure the thickness of the curled mouth portion 30, particularly at the corner portions 23. That is, since tension can occur on both the long and short sides of the curled mouth portion 30 at the corner portions 23, the central portion is particularly likely to become thinner (the curl diameter becomes smaller). In contrast, by having the protrusions PP enter the curled mouth portion 30 at the corner portions 23 as in this embodiment, the protrusions PP can prevent the curl diameter from becoming smaller.

[0041] 7 shows cross-sectional views of the corner bottom 23b of the curled fiber material container 100 according to the embodiment taken at predetermined heights from the bottom panel 10. As can be seen from the figure, the cross-section of the corner portion 23 near the corner bottom 23b is taken along the line E-E, and the cross-sections taken at predetermined heights upward in the Z direction from this line E-E are shown as D-D, C-C, B-B, and A-A.

[0042] For example, in cross section A-A, which is located at approximately the midpoint of corner portion 23, it can be seen that the area including end 21e of short side panel 21 overlaps with the area including end 22e of long side panel 22. In this embodiment, since blank BK shown in Figure 5 is used, the overlapping area between short side panel 21 and long side panel 22 gradually decreases as one moves downward from cross section A-A.

[0043] On the other hand, in cross section E-E, which shows the vicinity of the corner bottom 23b, it can be seen that the action of the side protrusion 24 described above causes the paper material (fibers) to condense near the corner bottom 23b, thereby preventing the formation of pores, etc.

[0044] 8 shows several cross-sectional views from the inside to the outside of the corner bottom 23b of the curled fiber material container 100 according to the embodiment. As can be seen from Fig. 8, in the inner cross section taken along line ii near the corner bottom 23b where the contents are stored, the degree of aggregation of the paper material is not so strong and pores are formed.

[0045] On the other hand, in the M-M cross section, which is shifted outward from the i-i cross section, the width of the pores is significantly narrowed, and it can be seen that in the O-O cross section, which is located even further outward, the pores are completely blocked.

[0046] In this way, in the curled fiber material container 100 of this embodiment, the upper end of either the short side panel 21 or the long side panel 22 that make up the corner portion 23 becomes the curled mouth portion 30 during the above-mentioned molding, and the upper end of the other panel that corresponds to the location of this curled mouth portion 30 is provided with the above-mentioned missing area MA and protrusion PP. This makes it possible to reinforce the curled mouth portion 30 with the protrusion PP and improve the moldability of the curled shape.

[0047] The embodiment described above is an example that embodies the gist of the present invention, and appropriate modifications may be made without departing from the gist of the present invention. Furthermore, known structures and methods may be appropriately added and modified without departing from the gist of the present invention.

[0048] In the following, preferred modifications of this embodiment will be described. In the various modifications described below, components having the same functions and actions as those already described in the above embodiment will be assigned the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0049] <Modification 1> Fig. 9 shows a curled fiber material container 110 according to Modification 1. In the curled fiber material container 100 according to the embodiment described above, the side protrusions 24 are provided at the ends 22e of the long side panels 22. In contrast, in the curled fiber material container 110 according to Modification 1, the side protrusions 24 are provided at the ends 21e of the short side panels 21.

[0050] 9, the side protrusion 24 in the first modification is a triangular portion including a base point 24a that substantially coincides with the intersection IP described above, a vertex 24b that serves as a branch point that separates from the long side panel 22 when the container is blank, and an outer end point 24c of the end 21e of the short side panel 21 that is the farthest from the intersection IP. The curled fiber material container 110 according to the first modification described above can also achieve the same effects as those shown in the above embodiment.

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

[0052] More specifically, as shown in Figure 10, the side protrusion portion 24 in variant example 2 is two line-symmetric triangular portions including a base point 24a that approximately coincides with the above-mentioned intersection point IP, vertices 24s and 24t that become branch points that move away from the long side panel 22 when blank, and two outer end points 24c (the outer end point of the end 21e of the short side panel 21 that is farthest from the intersection point IP, and the outer end point of the end 22e of the long side panel 22 that is farthest from the intersection point IP).

[0053] In this way, the side projection 24 of the present invention may be provided on at least one of the end 21 e of the short side panel 21 and the end 22 e of the long side panel 22. The curled fiber material container 120 according to the modified example 2 described above can also achieve the same effects as those shown in the above-described embodiment and modified example 1. Note that the two triangular shapes constituting the side projection 24 in modified example 2 may be the same shape as each other so as to be line-symmetrical, or may be different shapes.

[0054] <Modification 3> Fig. 11(a) shows a curled fibrous material container 130 according to Modification 3. In the curled fibrous material containers according to the above-described embodiment, Modification 1 and Modification 2, the base points 24a of the side projections 24 are arranged so as to substantially coincide with the intersection points IP. In contrast, the curled fibrous material container 130 according to Modification 3 has a short ruled line RL １ and long ruled line RL ２ The intersection IP and the base point 24a are not coincident with each other, but are located close to each other.

[0055] More specifically, as shown in FIG. 11B, the long ruled line RL in Modification 3 ２The short ruled line RL is formed at the corner portion 23. １ The side projection 24 in the third modification has a base point 24a that is located at the end of the extension line RLL.

[0056] In this way, in the side projection portion 24 of the present invention, the base point 24a does not necessarily have to coincide with the intersection point IP, and the base point 24a may be located close to the intersection point IP as in the present modified example 3. ２ The ruled line RL has an extension line RLL. １ The curled fiber material container 130 according to the third modification described above can also achieve the same effects as those achieved in the above-described embodiment.

[0057] 12 shows a curled fibrous material container 140 according to Modification 4. In the curled fibrous material container 100 according to the embodiment described above, the outer edge side end surface ES of the short side panel 21 and the long side panel 22 on the side having the missing area MA is ３ In contrast to this, in the curled fiber material container 140 according to the fourth modification, a single protrusion PP is arranged near the center MAc of the missing region MA. ３ A plurality of protrusions PP are formed on the surface.

[0058] More specifically, the protrusion PP in the fourth modification includes a first protrusion PP1 and a second protrusion PP2 having a width equal to or narrower than that of the first protrusion PP1. The first protrusion PP1 has the first width W1 and is spaced apart from the outer edge end surface ES near the center MAc of the missing area MA. ３ On the other hand, the second protrusion PP2 has a second width W2 that is equal to or smaller than the first width W1, and is disposed on the outer edge side end surface ES at a predetermined gap on the end MAe side of the missing region MA relative to the first protrusion PP1. ３In this way, the width W1 of the protrusion (first protrusion PP1) located at the center MAc of the missing area MA may be set to be equal to or greater than the width W2 of the protrusion (second protrusion PP2) located on the end MAe side.

[0059] As shown in the figure, the second protrusions PP2 are located on the outer edge side end surface ES in the missing area MA so as to sandwich the first protrusions PP1. ３ In the case where a plurality of second protrusions PP2 are arranged, the width W2 of the plurality of second protrusions PP2 may be the same or may have different widths. In addition, although the first protrusion PP1 is shown as a single protrusion in the drawing, it may be formed on the outer edge side end surface ES in the missing region MA, similar to the second protrusion PP2. ３ When a plurality of first protrusions PP1 are arranged, the plurality of first protrusions PP1 may have the same width or different widths from each other, as long as the width is equal to or greater than the width W2 of the second protrusions PP2 from the viewpoint of reinforcing the curled mouth portion 30.

[0060] In this way, a plurality of protrusions PP may be arranged intermittently from the center MAc toward the end MAe of the missing region MA. In the curled fiber material container 140 according to the fourth modification described above, the same effects as those shown in the above embodiment can be obtained, and in addition, the strength of the curled opening 30 can be further increased while maintaining the ease of forming into a curled shape.

[0061] The present invention can be used to manufacture, for example, a curled bottomed container that can ensure uniform sealing even if the container is made primarily of paper and has a polygonal bottom surface (bottom panel).

[0062] 100-140 Curled fiber material container 10 Bottom panel 20 Side wall portion 21 Short side panel 22 Long side panel 23 Corner portion 24 Side overhang portion 30 Curled mouth portion

Claims

1. A curled fiber material container having an open top and curled edges, comprising: a polygonal bottom panel defined by a line; a first and a second side panel each connected to the bottom panel via the line, said side wall portions being inclined so as to expand in a fan-like manner from the line to the edge of the opening; and a curled mouth portion where the upper end of the side wall portion is rolled up in a curl; said side wall portions have a corner portion where both ends of the first and second side panels overlap, and at least one of the end faces of the first and second side panels constituting the corner portion is formed with a side protrusion portion that is positioned adjacent to the line of the bottom panel and protrudes toward the other of the end faces of the first and second side panels.

2. The thickness of the bottom panel and the side wall is 225 μm to 555 μm, and the paper density is 0.55 g / cm ３ ~0.85g / cm ３ 2. The container made of curled fiber material according to claim 1, wherein 3. A curled fiber material container as described in claim 1, wherein the bottom panel is divided by rectangular lines, and the side projections are provided at the four corner portions of the bottom panel.

4. A curled fiber material container as described in any one of claims 1 to 3, wherein the side protrusion is formed on the end face of one of the first and second side panels that is located on the outside at the corner portion, and the side protrusion is fixed to the outer face of the one of the first and second side panels that is located on the inside at the corner portion.

5. A container made of curled fiber material as described in claim 4, wherein no lines are provided on the side wall portion and at least a portion of the first side panel and the second side panel are fixed to each other so as to overlap each other at the corner portions.

6. A curled fiber material container as described in claim 4, wherein one of the end faces of the first side panel and the second side panel which have the side protrusion and constitute the corner portion has a missing area and the outer edge side end face on the side having the missing area has a protrusion which is contained within the curled mouth portion, and the other of the first side panel and the second side panel which corresponds to the missing area becomes the curled mouth portion.

7. A curled fiber material container as described in claim 4, wherein the lines include a first line that separates the bottom panel from the first side panel and a second line that separates the bottom panel from the second side panel, the second line having an extension line extending from an intersection with the first line at the corner portion, and the side protrusion portion is positioned based on an end of the extension line.

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