Paper container

Abstract

To provide an art for overcoming a difficulty in opening which can be observed in parts of products.SOLUTION: A paper container of the application comprises: a bottom part 2; a body part 3 erected from the bottom part by curling a blank 30 formed by lamination of a paper base material 36 and resin covers 37, 38, and joining both side ends 31, 32 to each other; a flange part 4 extending outward from an upper part of the body part 3 forming an upper part of the blank 30; and a lid part 6 joined to the flange part 4 through a seal surface 60. The paper container includes a protection tape 50 which covers an end surface of an end 31 located at the inner side of both side ends of the blank to protect the end surface. An upper part 51 of the protection tape 50 comprises: a seal surface corresponding part 53 corresponding to the seal surface 60; and a seal surface outside part 53 located at the outer side (the upper side) of the seal surface corresponding part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a paper container having a body formed by rolling a blank, a flange extending outward from the upper part of the body, and a lid sealed to the flange. [Background technology]

[0002] In recent years, from the viewpoint of environmental conservation, the use of paper containers instead of plastic containers has been considered. A paper container has, for example, a circular bottom, a body part extending upright from the bottom in an inverted truncated cone shape or a cylindrical shape, a flange part extending outward from the upper part of the body part, and a lid part sealed to the flange part.

[0003] The body is formed from a sector-shaped blank. The blank is rolled, one end is placed underneath the other end, and the other end is placed on top of it so that the joining surfaces face each other. The two ends are then overlapped and joined (for example, by heat welding) to a predetermined joining width.

[0004] Paper containers are used to store food products, including beverages and oils. For this reason, at least the sides corresponding to the inside of the body and bottom are coated with resin. This prevents liquids, oils, etc. from seeping out of the container. The sides corresponding to the outside are generally also coated with resin.

[0005] However, the blank end faces are not resin-coated at the joint (seam), which means that liquids, oils, etc. may leak out of the container from the body joint through the blank end faces.In addition, oxygen and water vapor may enter from the outside through the blank end faces, which may be an indirect cause of deterioration of the contents.

[0006] In response to this, a skive hemming process may be performed in which a predetermined length of the blank end is shaved off, half the blank thickness, and the remaining shaved off portion is folded back so that the cut surface is on the inside, preventing the blank end surface from being exposed (for example, Patent Document 1).

[0007] In addition, edge protection treatment is sometimes performed in which protective tape is applied to the end of the blank to cover the blank end face (for example, Patent Document 2). When the body portion is formed, the upper part of the blank is extended outward to form a flange portion. Therefore, the joint portion of the body portion extends to the flange portion. The protective tape in edge protection treatment also extends to the flange portion. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-312636 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-215249 Summary of the Invention [Problem to be solved by the invention]

[0009] When eating the contents of the container, the user pulls up the tab provided on the outer edge of the lid, peels off the seal on the lid, and opens the container.

[0010] In some cases, however, it has been found that some products are difficult to open, or that the resin coating on the inner surface of the container is peeled off when the container is forcibly opened. The peeled off area can become soiled by the contents and is also unsightly in appearance.

[0011] The present invention is intended to solve the above-mentioned problems, and aims to provide a technology that eliminates the difficulty in opening that is often found in some products. [Means for solving the problem]

[0012] The above problem does not always occur, but has been found in some products. When the inventor investigated the cause of the problem, he found that it occurs when the position of the tab on the lid and the joint (seam) of the body are roughly aligned. He further inferred that the cause may be the protective tape that extends to the flange. After such trial and error, the inventor came up with the idea for the present invention.

[0013] The paper container of the present invention, which achieves the above-mentioned object, comprises a bottom, a body portion erected from the bottom by rolling a blank made of a laminate of a paper base material and a resin coating and joining both side edges, a flange portion extending outward from the upper part of the body portion at the top of the blank, and a lid portion joined to the flange portion via a sealing surface. Furthermore, the container comprises a protective tape that covers and protects the inner end faces of both side edges of the blank. The upper part of the protective tape comprises a sealing surface equivalent portion that corresponds to the sealing surface, and an outer sealing surface portion located outside (above) the sealing surface equivalent portion.

[0014] The inventors discovered that when the distal corner of the protective tape is located within the sealing surface, the distal corner becomes the peeling starting point, causing problems. In the present invention, the distal corner of the protective tape, i.e., the outer corner of the sealing surface, does not become the peeling starting point, so problems do not occur. There is also no difficulty in opening the package.

[0015] In the above invention, the shortest length of the outer seal surface is preferably 20% or more of the longest length of the seal surface equivalent portion.

[0016] This ensures the effect of the present invention. [Effects of the Invention]

[0017] The paper container of the present invention can prevent the problem of being difficult to open, which has been observed with some products. Since there is no need to forcefully open the container, the resin coating on the inner surface of the container will not peel off. [Brief explanation of the drawings]

[0018] [Figure 1] Overall view of blank and protective tape [Figure 2] Detailed drawing of blank and protective tape [Figure 3] Schematic diagram of edge protection processing [Figure 4] Overall view of the container body and lid [Figure 5] Explanation of the malfunction [Figure 6] Explanation of the malfunction [Figure 7] Detailed configuration comparison diagram between the conventional example and the embodiment [Figure 8] Cross-sectional view of an embodiment DETAILED DESCRIPTION OF THE INVENTION

[0019] ~General configuration~ The overall schematic configuration of a typical paper container will be described using Figures 1 to 4. Figure 1 is a plan view showing the overall configuration of the blank and protective tape. Figure 2 is a perspective view showing the detailed configuration of the blank and protective tape. Figure 3 is a cross-sectional view explaining the outline of edge protection processing. Figure 4 is a perspective view showing the schematic relationship between the container body and the lid. In addition to the general configuration, Figures 1 to 4 also show configurations specific to this application.

[0020] The lidded container consists of a container body 1 and a lid 6. The container body 1 is made of paper and is generally laminated. The container body 1 has a bottom 2 (not shown), a body 3, and a flange 4. The bottom 2 is circular in plan view. The body 3 is roughly in the shape of an inverted truncated cone in side view and stands upright from the bottom 2. The flange 4 is formed so as to extend outward from the upper end of the body 3.

[0021] The body 3 is formed by overlapping both ends of a roughly fan-shaped paper blank 30. The blank is rolled up, with one end 31 facing downward (inside) and the other end 32 facing upward (outside), so that the joining surfaces of the one end and the other end face each other, and the two ends are overlapped and joined at a predetermined joining width. This forms the body joint 33.

[0022] The flange portion 4 is formed so as to extend outward from the upper end of the body portion 3. When the body portion 3 is formed from the main portion of the paper blank 30, the flange portion 4 is formed from the upper portion of the paper blank 30.

[0023] The paper blank 30 may have both ends 41, 42 cut out at the location corresponding to the flange 4. The upper part of the paper blank 30 is rolled or folded back to form the flange 4. The cut out portion can suppress excess material at the joint. The cross-sectional shape of the flange can be curled or flat.

[0024] The joint 33 in the body 3 extends to the flange 4, and a joint 43 of the flange 4 is formed.

[0025] At least the inside of the paper blank 30 is resin coated (laminated). The inside 37 and outside 38 of the base material 36 may be resin coated. Polyethylene, polyethylene terephthalate, or the like is used as the resin. The resin layer may be multi-layered. For the sake of convenience, the areas corresponding to the flanges are referred to as the base material 46 and the resin coatings 47 and 48, but they are continuous with the base material 36 and the resin coatings 37 and 38, respectively.

[0026] The lid 6 has a shape (generally circular) corresponding to the opening formed by the flange portion 4. The lid material is made of, for example, a laminate of polyethylene, polyethylene terephthalate, aluminum, polyethylene, and a sealant, but is not limited to these.

[0027] The outer periphery of the lid 6 and the flange 4 are bonded via the sealing surface 60. More specifically, the sealant on the back of the lid 6 and the resin coating 47 of the flange 4 are heat-sealed together, thereby sealing the contents.

[0028] The outer periphery of the lid 6 is partially extended to form a tab 7. The seal can be peeled off by pulling up the tab 7, making it possible to open the container. Therefore, the tab 7 is not sealed.

[0029] At least one end 31 of the paper blank 30 is covered with a protective tape 50 for edge protection. The protective tape 50 extends along the blank end and is folded back at the central axis of the tape. This prevents the contents from seeping through the end of the base material 36.

[0030] For example, the thickness of the paper blank 30 is 0.4 mm, and the thickness of the protective tape 50 is 50 μm.

[0031] ~ Knowledge gained in the process of arriving at this invention ~ When the contents of the container are to be eaten, the container is opened by pulling up the tab 7 provided on the outer edge of the lid 6 and peeling off the sealing surface 60. At this time, some defects have been found in some products.

[0032] The above-mentioned problem does not always occur, and when the inventor investigated the cause of the problem, he found that the problem occurs when the position of the handle portion 7 of the lid 6 and the position of the body joint (seam portion) 33 roughly coincide in a plan view, and as a result, the position of the handle portion 7 and the position of the flange joint 43 roughly coincide.

[0033] It is possible to recognize the positions of the knob 7 and the flange joint 43 and place them on opposite sides, but this would require improving the existing device for position recognition. If possible, it is preferable to continue using the existing device.

[0034] 5 is an explanatory diagram of the occurrence of a malfunction. It shows a comparison image of a case where the position of the knob 7 does not match the position of the flange joint 43 (normal, no malfunction) and a case where the position of the knob 7 matches the position of the flange joint 43 (malfunction).

[0035] The sealing surface 60 in the normal area is formed by heat welding the sealant on the back of the lid 6 to the resin coating 47 on the flange portion 4, whereas the sealing surface 60 in the defective area is formed by heat welding part of the sealant on the back of the lid 6 to the upper end of the protective tape 50.

[0036] Furthermore, the cross-sectional thickness of the normal portion is the thickness of one blank, whereas the cross-sectional thickness of the defective portion is slightly thicker because two blanks are compressed. As a result, the rigidity of the defective portion is higher than that of the normal portion. In addition, the amount of resin coating 47 is also increased, and the resin density is also increased due to compression.

[0037] 6A and 6B are diagrams illustrating the mechanism behind the occurrence of the defect. The knob 7 is pulled up to peel off the sealing surface 60 (FIG. 6A).

[0038] At this time, the flange portion 4 has high rigidity, and the protective tape 50 and the resin coating 47 are strongly welded to the lid 6, making them difficult to peel at the sealing surface 60. If further force is applied, peeling will occur between the base material 46 and the resin coating 47 (FIG. 6B).

[0039] If the lid 6 is forcibly peeled off, peeling occurs between the base material 36 that is continuous with the base material 46 and the resin coating 37 that is continuous with the resin coating 47. The inner resin coating becomes peeled off.

[0040] That is, it was inferred that the cause of the defect was the extension of the protective tape 50 to the flange portion 4. However, if the protective tape 50 does not extend to the flange portion 4 and completely cover the blank end surface, there is a risk of leakage from the inside or intrusion from the outside through the body joint portion 33.

[0041] ~Comparison between conventional example and practical example~ Furthermore, the inventors have investigated the causes of the above-mentioned problems.

[0042] Figure 7 shows a comparison image of the conventional example and the improved example (embodiment). The upper image shows the top surface of the flange, and the lower image shows the corresponding blank end. Figure 8 is a cross-sectional view of the embodiment of the present invention.

[0043] In the conventional example, the protective tape 50 extends along the blank end face to the flange portion 4. The upper portion 51 of the protective tape 50 is included in the sealing surface 60. As a result, the corner portion 52 of the protective tape distal to the end face is located within the sealing surface.

[0044] It is presumed that the corner 52 is the starting point for peeling between the substrate 46 and the resin coating 47, causing the above-mentioned problem.

[0045] In contrast, in the embodiment, the protective tape 50 extends up to the flange portion 4 near the end face, but the upper portion 51 of the protective tape 50 extends to a position that completely includes the sealing surface 60.

[0046] The upper portion 51 of the protective tape is composed of a sealing surface equivalent portion 53 that corresponds to the sealing surface 60 and an outer sealing surface portion 54 that is located outside (above) the sealing surface equivalent portion 53. As a result, a corner portion 55 of the protective tape distal to the end face is located outside the sealing surface 60.

[0047] In the illustrated example, a notch is provided at the end of the blank, and therefore the seal surface 60 is formed to correspond to the shape of the blank notch. As a result, the upper side of the seal surface equivalent portion 53 near the end face is scraped away, and the seal surface outer portion 54 near the end face protrudes below the illustration.

[0048] For convenience, the longest length of the seal surface equivalent portion 53 (i.e., the length of the range that has not been cut off) is considered to be the length of the seal surface equivalent portion 53, and the shortest length of the seal surface exterior 54 (i.e., the length of the range that has not protruded) is considered to be the length of the seal surface exterior 54.

[0049] The length of the seal surface outer portion 54 must be more than 0% of the length of the seal surface equivalent portion 53, but in practice, the effect of the present invention will be more certain if it is 10% or more, or even 20% or more.

[0050] However, it is undesirable for the upper end of the protective tape 50 to protrude beyond the upper end of the blank. In practice, the length of the outer sealing surface 54 is preferably less than 100%, and more preferably less than 70%, of the length of the portion 53 corresponding to the sealing surface.

[0051] When the tab 7 is pulled up to peel off the sealing surface 60, the corner 55 of the protective tape does not become the peeling starting point, preventing the occurrence of defects.

[0052] A prototype model corresponding to the above embodiment was created, and the tab 7 was pulled up to peel off the sealing surface 60. It was found that it could be opened with 70 to 80 percent of the force required for the conventional example, and no problems such as peeling occurred.

[0053] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the technical concept of the present invention.

[0054] For example, the upper edge line of the protective tape 50 is formed in a straight line in a direction perpendicular to the extending direction of the blank end face, but it may also be cut obliquely or in a curved line. [Explanation of symbols]

[0055] 1 Container body 2 bottom 3. Torso 4 Flange 6 Lid 7. Knob 30 paper blanks 31,32 Blank end 33 Body joint 36 Blank substrate 37,38 Resin coating 41,42 Blank end 43 Flange joint 46 Blank substrate 47,48 Resin coating 50 protective tape 51 Top of the tape 52 Tape corner 53 Seal surface equivalent part 54 Seal surface exterior 55 Tape corner

Claims

1. The container comprises a bottom portion, a trunk portion formed by rolling a blank made of a laminate of a paper base material and a resin coating and joining both side ends thereof to form an upright container from the bottom portion, a flange portion formed at the top of the blank and extending outward from the top of the trunk portion, and a lid portion joined to the flange portion via a sealing surface, A protective tape is provided to cover and protect the inner end faces of both side ends of the blank, The upper portion of the protective tape is composed of a sealing surface equivalent portion corresponding to the sealing surface and an outer sealing surface portion located outside (above) the sealing surface equivalent portion. A paper container characterized by:

2. In the upper portion of the protective tape, the shortest length outside the sealing surface is 20% or more of the longest length of the portion corresponding to the sealing surface.

2. The paper container according to claim 1.

3. The paper container according to claim 1 is formed using Covered and protected by the protective tape A blank characterized by:

Images