container

Abstract

To provide a container which prevents propagation of a crack to an opening even if a crack is generated in a flange part, and can suppress extension of breakage.SOLUTION: A container 1 includes a container body 2 having an opening M, a lid boy 3 closing the opening M, and a joint part 13 where the container body 2 and the lid body 3 are joined to each other, wherein the container body 2 includes a body side flange 5 provided along a peripheral edge Ma of the opening M, the lid body 3 includes a lid side flange 6 stacked on the body side flange 5, the joint part 13 is provided in a stacked area A of the body side flange 5 and the lid side flange 6, and the stacked area A of the body side flange 5 and the lid side flange 6 is provided with a first rib 71 and a third rib 81 which are arranged between the joint part 13 and the opening M, and are provided along the peripheral edge Ma of the opening M.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a container for storing contents such as food.

Background Art

[0002] As a container for storing and packaging contents such as food, for example, a container made of foamed resin or a container formed from a resin sheet material is known. This container includes a container body having an opening for taking in and out food and the like, and a lid body attached to the container body to close the opening. The lid body and the container body are provided with flange portions that overlap each other. The flange portions are fusion-bonded by heat generation using, for example, ultrasonic vibration (see Patent Documents 1 to 4).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described container, since the flat surfaces of the flange portions are fusion-bonded, the bonding force becomes strong and it becomes difficult to open. As a result, when trying to peel the flange portions apart with force to open the lid body, the flange portion tears, and furthermore, the tear propagates and the damage is likely to expand.

[0005] The present invention aims to solve the above problems and to provide a container that can prevent a crack from propagating to the opening even if a crack occurs in the flange portion, thereby suppressing the expansion of damage. [Means for solving the problem]

[0006] The present invention comprises a container body having an opening, a lid that closes the opening, and a joint that joins the container body and the lid. The container body has a body-side flange provided along the periphery of the opening, the lid has a lid-side flange laminated on the body-side flange, and the joint is provided in the laminated region between the body-side flange and the lid-side flange. The laminated region is provided with a damming rib positioned between the joint and the opening and along the periphery of the opening.

[0007] In the container described above, a damming rib is provided in the laminated region of the main body flange and the lid flange where the joint is located. The damming rib is positioned between the joint and the opening and is provided along the periphery of the opening. In other words, even if a tear occurs when opening the lid from the container body, the propagation of the tear is prevented by the damming rib before it reaches the opening, and does not reach the opening. As a result, the expansion of damage can be prevented.

[0008] In the above container, the damming rib may be provided in the laminated region of the lid-side flange. If a crack occurs in the lid, the damming rib can prevent the propagation of the crack.

[0009] In the above-described container, the damming ribs may be provided on the lid-side flange and the body-side flange. If a crack occurs in one or both of the lid and / or container body, the damming ribs can prevent the crack from spreading.

[0010] In the above container, the lid-side flange comprises a lid-side laminated inner surface facing the body-side flange and a lid-side laminated outer surface opposite to the lid-side laminated inner surface, and the body-side flange comprises a body-side laminated inner surface facing the lid-side flange and a body-side laminated outer surface opposite to the body-side laminated inner surface, and the damming rib may be provided so as to protrude from at least one of the lid-side laminated outer surface and the body-side laminated outer surface. By providing the damming rib so as to protrude from the lid-side laminated outer surface or the body-side laminated outer surface, rather than from the lid-side laminated inner surface or the body-side laminated inner surface, the joining of the lid-side laminated inner surface and the body-side laminated inner surface becomes less affected, which is advantageous in terms of joinability.

[0011] In the above container, the lid flange and the body flange may be provided with reinforcing ribs connected to the damming ribs. Providing reinforcing ribs makes it easier to prevent the lid from tearing when opening it.

[0012] In the above container, the lid flange comprises a first flange portion extending along the periphery of the opening, a second flange portion extending along the periphery of the opening, and a handle portion positioned between the first and second flange portions. The damming ribs may be provided on both the first and second flange portions. Even if a tear occurs when the lid is peeled off the container body by grasping the handle portion, the tear is prevented by the damming ribs on both the first and second flange portions, thereby suppressing the propagation of the tear and preventing the damage from spreading.

[0013] The present invention relates to a container comprising a lid that closes the opening of the container body, wherein the container body comprises a body-side flange provided along the periphery of the opening, and the lid comprises a lid-side flange that is laminated on the body-side flange, and at least one of the planned lamination region of the body-side flange that is to be laminated on the lid-side flange and the planned lamination region of the lid-side flange that is to be laminated on the body-side flange is provided with a damming rib provided along the periphery of the opening.

[0014] In the above-described container, a retaining rib is provided in at least one of the planned lamination regions of the main body side flange and the lid side flange. That is, when the main body side flange and the lid side flange are joined in the planned lamination region so that the retaining rib is arranged between the joint and the opening, even if a tear occurs when the lid is opened from the container body, the propagation of the tear is blocked by the retaining rib before reaching the opening and does not reach the opening. As a result, the expansion of damage can be prevented.

Advantages of the Invention

[0015] According to the present invention, even if a tear occurs during opening, the propagation of the tear to the opening can be prevented, and the expansion of damage can be suppressed.

Brief Description of the Drawings

[0016] [Figure 1] It is a perspective view showing a container in which a lid is joined to a main body container according to the first embodiment of the present invention. [Figure 2] It is a plan view showing a container in which a lid is joined to a main body container. [Figure 3] It is a plan view showing an enlarged part of the container shown in FIG. 2 and showing a part of the lid broken. [Figure 4] It is a cross-sectional view taken along line IV-IV of FIG. 3. [Figure 5] It is a perspective view showing a container with the lid open. [Figure 6] It is a plan view showing a container with the lid open. [Figure 7] Modification examples of the main body side flange and the lid side flange are shown. FIG. (a) is a cross-sectional view of the main body side flange and the lid side flange according to the first modification example, and FIG. (b) is a cross-sectional view of the main body side flange and the lid side flange according to the second modification example. [Figure 8] A container according to the second embodiment is shown. FIG. (a) is a plan view of the container with the lid open, and FIG. (b) is a plan view of the container with the lid closed. [Figure 9]Shows the container according to the third embodiment. Figure (a) is a plan view of the container with the lid open, and Figure (b) is a side view of the container with the lid open. [Figure 10] It is an explanatory diagram schematically showing an example of an ultrasonic sealing machine.

Mode for Carrying Out the Invention

[0017] Hereinafter, the container according to the embodiment of the present invention will be described while referring to the drawings. Note that the container of the present invention is not limited to this embodiment only.

[0018] The container 1 of the first embodiment is a food packaging container mainly for storing and packaging food. However, the contents of the container 1 are not limited to food, and include utensils such as chopsticks and spoons used when eating and other objects. Note that the containers 1A and 1B according to the second and third embodiments described later are the same, and the contents are not limited to food, but include other objects.

[0019] As shown in FIGS. 1 and 5, the container 1 includes a container body 2, a lid 3, and a hinge portion 4 that connects the container body 2 and the lid 3 so as to be openable and closable. The container body 2 has an opening M for taking in and out the contents. The lid 3 is connected to the container body 2 via the hinge portion 4 so as to be able to open and close the opening M. That is, the container 1 is a resin-made hood pack in which the lid 3 and the container body 2 are integrally sheet-molded by the hinge portion 4.

[0020] In this embodiment, the depth of the lid 3 is shallower than the depth of the container body 2, and the contents cannot be held by the lid 3 substantially. Therefore, the container body 2 and the lid 3 can be clearly distinguished. However, it is also possible to adopt a form in which the contents can be held by both the container body 2 and the lid 3. In that case, one can be regarded as the container body 2 and the other as the lid 3.

[0021] Container 1 is made of a synthetic resin sheet and is manufactured by vacuum forming using a predetermined mold. Preferably, the synthetic resin used for container 1 is transparent so that the contents inside the container can be visually inspected. Examples of transparent synthetic resins include polystyrene-based, polyethylene-based, polypropylene-based, and polyester-based synthetic resins. In this embodiment, for example, a polystyrene sheet is used. Note that container 1 may be semi-transparent or opaque.

[0022] Furthermore, it is preferable that the synthetic resin sheet used in the container 1 is a stretched sheet manufactured by stretching the synthetic resin so that the molecules of the synthetic resin are oriented, in terms of the mechanical strength of the molded container 1. Also, a biaxially oriented sheet is more preferable than a uniaxially oriented sheet because it has a better balance of physical properties. In particular, a biaxially oriented sheet of polystyrene resin has well-balanced performance in terms of rigidity, heat resistance, transparency, environmental friendliness, and processability, making it suitable as a material for the container 1. In this embodiment, for example, a biaxially oriented sheet of polystyrene resin is used.

[0023] Next, the structure of the container body 2 and the lid 3 will be described. As shown in Figures 5 and 6, the general shape of the container body 2 when open is a roughly rectangular shape when viewed from above. The top of the container body 2 is open, forming an opening M. The container body 2 has a bottom 21 provided at the bottom opposite to the opening M, and side walls 22 erected from the periphery of the bottom 21. The bottom 21 has irregularities to support the contents such as food stored inside in a slightly elevated position. The side walls 22 are provided with a plurality of vertical ribs 22a.

[0024] The container body 2 is equipped with a body-side flange 5 that is joined to the lid 3. The body-side flange 5 is bent from the upper end of the side wall 22 and is provided to protrude outward. Here, "outward" refers to the direction opposite to the inside (inner side) where the contents are contained, with respect to the opening M. The body-side flange 5 is provided to follow a part of the periphery Ma of the opening M, avoiding the hinge portion 4. For example, the periphery Ma of the opening M in this embodiment is substantially rectangular. The hinge portion 4 is provided along one of the four sides of the periphery Ma of the opening M, and the body-side flange 5 is provided along the other sides.

[0025] As shown in Figures 1, 2, 5, and 6, the lid 3 comprises a cover portion 31 and a lid-side flange 6 that extends from the peripheral edge 31a of the cover portion 31. The cover portion 31 covers the opening M when the lid 3 is folded back at the hinge portion 4 and attached to the container body 2. The lid-side flange 6 is stacked on the body-side flange 5 when the opening M is covered by the cover portion 31, that is, when the opening M is closed with the lid 3. Therefore, the open lid-side flange 6 has a stacking area Ay that is to be stacked on the body-side flange 5, and the body-side flange 5 has a stacking area Ax that is to be stacked on the lid-side flange 6. The area formed by the overlap of the stacking area Ay and the stacking area Ax is the stacking area A.

[0026] The cover portion 31 has a shape that conforms to the shape of the opening M in a plan view, and in this embodiment, it is a roughly rectangular shape that conforms to the roughly rectangular opening M. The cover portion 31 is formed into a three-dimensional surface shape that has depth (bulge) on the opposite side from the container body 2 when the opening M is closed.

[0027] The lid-side flange 6 is positioned to follow a portion of the peripheral edge 31a of the cover portion 31, avoiding the hinge portion 4. The peripheral edge 31a of the cover portion 31 is roughly rectangular, following the shape of the peripheral edge Ma of the opening M, and the hinge portion 4 is connected to one of its four sides. The lid-side flange 6 is stacked on the body-side flange 5 when the opening M is covered by the cover portion 31. In other words, when the opening M is closed with the lid 3, the lid-side flange 6 is positioned to follow a portion of the peripheral edge Ma of the opening M, similar to the body-side flange 5.

[0028] Next, the structure of the main body flange 5 and the lid flange 6 will be described with reference to Figures 3 and 4. Figure 3 is a plan view showing an enlarged portion of the container 1, mainly showing a part of the stacked region A of the main body flange 5 and the lid flange 6. Figure 4 is a cross-sectional view of the container 1 shown in Figure 3.

[0029] When the opening M is closed with the lid 3, the main body flange 5 and the lid flange 6 are stacked on top of each other. The main body flange 5 has an inner surface facing the lid flange 6 (main body stacked inner surface 5a) and an outer surface opposite to the main body stacked inner surface 5a (main body stacked outer surface 5b). The lid flange 6 has an inner surface facing the main body flange 5 (lid stacked inner surface 6a) and an outer surface opposite to the lid stacked inner surface 6a (lid stacked outer surface 6b).

[0030] The region where the inner surface 5a of the main body side laminate and the inner surface 6a of the lid side laminate overlap is the laminate region A of the main body side flange 5 and the lid side flange 6. As a result of fusion bonding or the like being performed within the laminate region A, a joint portion 13 is formed that joins the main body side flange 5 and the lid side flange 6.

[0031] The main body side flange 5 is provided with a rib structure 7 that protrudes from the main body side laminated outer surface 5b. The rib structure 7 comprises a plurality of first ribs 71 provided along the periphery Ma of the opening M, and a plurality of second ribs 72 provided connected to the first ribs 71. Assuming the container 1 is in an open state, the first ribs 71 and second ribs 72 are provided in the planned laminated area Ax. Assuming the container 1 is in a closed state, the first ribs 71 and second ribs 72 are provided in the laminated area A. The second ribs 72 are an example of reinforcing ribs that prevent tearing when opening. The first ribs 71 are an example of damming ribs that prevent the propagation of tearing if a tear occurs. In this embodiment, the rib structure 7 is provided to protrude from the main body side laminated outer surface 5b, but it is also possible to provide the rib structure 7 to protrude from the main body side laminated inner surface 5a so as to avoid the joint 13.

[0032] The first rib 71 is a protruding portion that extends in one direction. The first rib 71 extends along the periphery Ma in its longitudinal direction. Multiple first ribs 71 are arranged linearly along the periphery Ma of the opening M, and are provided to surround the periphery Ma except for the portion along the hinge portion 4 (see Figures 1 and 2). For example, of the rectangular periphery Ma, a single first rib 71 is provided on each of the opposing short sides, and multiple first ribs 71 are provided on the long side opposite the hinge portion 4. Also, no first ribs 71 are provided at the corners of the periphery Ma. These first ribs 71 are provided in the laminated region A and are provided close to the periphery Ma so as to be between the joint portion 13 and the opening M.

[0033] Each first rib 71 is provided with multiple second ribs 72 branching off from it. The second ribs 72 are protruding portions extending in one direction, and the longitudinal direction of the second ribs 72 is inclined with respect to the longitudinal direction of the first rib 71. The inclination angle α of the second ribs 72 with respect to the first rib 71 is preferably 30° or more and 70° or less, and more preferably 40° or more and 50° or less.

[0034] The lid-side flange 6 is provided with a rib structure 8 that protrudes from the outer surface 6b of the lid-side laminate. The rib structure 8 includes a plurality of third ribs 81 provided along the periphery Ma of the opening M when the lid 3 is closed, and a plurality of fourth ribs 82 provided to be connected to the third ribs 81. Assuming the container 1 is in an open state, the third ribs 81 and fourth ribs 82 are provided in the planned laminate region Ay. Assuming the container 1 is in a closed state, the third ribs 81 and fourth ribs 82 are provided in the laminate region A. The fourth rib 82 is an example of a reinforcing rib that prevents the occurrence of tearing when opening. The third rib 81 is an example of a damming rib that prevents the propagation of tearing if a tear occurs. In this embodiment, the rib structure 8 is provided to protrude from the outer surface 6b of the lid-side laminate, but it is also possible to provide the rib structure 8 to protrude from the inner surface 6a of the lid-side laminate, avoiding the joint 13.

[0035] Figure 3 shows a portion of the lid 3 broken, revealing the third rib 81 and fourth rib 82 provided on the main body side flange 5 from the main body side laminated inner surface 5a. As shown in Figure 3, the third rib 81 is a unidirectional protrusion, and when the lid 3 is closed, its longitudinal direction extends along the peripheral edge Ma. Multiple third ribs 81 are provided to correspond to multiple first ribs 71, and when the lid 3 is closed, they are arranged to overlap each of the first ribs 71. The third ribs 81 are provided in the laminated region A, and when the lid 3 is closed, they are positioned between the joint 13 and the opening M.

[0036] Each third rib 81 is provided with multiple fourth ribs 82 branching off from it. The fourth ribs 82 are protruding portions extending in one direction, and the longitudinal direction of the fourth ribs 82 is inclined with respect to the longitudinal direction of the third rib 81. The inclination angle α of the fourth ribs 82 with respect to the third rib 81 is preferably 30° or more and 70° or less, and more preferably 40° or more and 50° or less. When the lid 3 is closed, the fourth ribs 82 and the second ribs 72 are arranged to intersect in a plan view, for example, in an X shape.

[0037] Container 1 is formed by vacuum forming of a synthetic resin sheet. Corresponding to the rib structure 7 formed on the outer surface 5b of the main body side laminated flange 5, a recessed structure 9 is formed on the inner surface 5a of the main body side laminated surface (see Figure 4). In other words, the back surface of the rib structure 7 is the recessed structure 9. Similarly, corresponding to the rib structure 8 formed on the outer surface 6b of the lid side laminated flange 6, a recessed structure 10 is formed on the inner surface 6a of the lid side laminated surface. In other words, the back surface of the rib structure 8 is the recessed structure 10.

[0038] In the container 1 according to the above embodiment, the first rib 71 or third rib 81, which functions as a damming rib, is provided on both the body side flange 5 and the lid side flange 6. In contrast, the damming rib can also be provided on either the body side flange 5 or the lid side flange 6. For example, Figure 7(a) is a cross-sectional view showing a first modified example of the body side flange 5 and the lid side flange 6, and Figure 7(b) is a cross-sectional view showing a second modified example. As shown in the first modified example, the rib structure 8 with the third rib 81 may be provided on the lid side flange 6 without providing the rib structure 7 on the body side flange 5. Also, as shown in the second modified example, the rib structure 7 with the first rib 71 may be provided on the body side flange 5 without providing the rib structure 8 on the lid side flange 6.

[0039] As shown in Figures 3 and 4, multiple joints 13 are provided in a spot manner in the laminated region A of the main body flange 5 and the lid flange 6. The joints 13 are formed, for example, by fusion welding. Now, referring to Figure 10, the method of joining the main body flange 5 and the lid flange 6 will be described. Figure 10 is a schematic explanatory diagram showing an ultrasonic sealing machine 100.

[0040] The ultrasonic sealing machine 100 includes a conveyor section 101, a pressure roller 102, and an ultrasonic horn 103. The container 1, with the lid 3 attached to the container body 2 so as to close the opening M, is conveyed in one direction by the conveyor section 101. The pressure roller 102 and the ultrasonic horn 103 are positioned on the movement trajectory of the body-side flange 5 and lid-side flange 6 of the container 1. The pressure roller 102 and the ultrasonic horn 103 are positioned opposite each other, with the overlapping body-side flange 5 and lid-side flange 6 in between.

[0041] The ultrasonic horn 103 has a vibrating surface 103a that vibrates in contact with the lid-side flange 6. The pressing roller 102 has a gear portion 102a that rotates while in contact with the main body-side flange 5. The gear portion 102a and the vibrating surface 103a sandwich the lid-side flange 6 and the main body-side flange 5. The ultrasonic vibrations applied from the vibrating surface 103a to the lid-side flange 6 and the main body-side flange 5 propagate into the interior of the lid-side flange 6 and the main body-side flange 5, causing the joining surfaces to heat up, resulting in a softening and melting phenomenon, which joins the lid-side flange 6 and the main body-side flange 5 together.

[0042] The shape of the joint surfaces of the main body flange 5 and the lid flange 6 depends, for example, on the shape of the gear portion 102a of the pressing roller 102, and can be formed in various ways. For example, the size and range of the joint surface depends on the size and shape of the protrusion facing the vibrating surface 103a of the gear portion 102a. Also, the spacing between multiple joint surfaces depends on the pitch of the gear portion 102a.

[0043] Next, with reference to Figure 8, the container 1A according to the second embodiment will be described. Container 1A has a structure common to container 1 according to the first embodiment. Therefore, in the following description, the differences will be the main focus, and for structures that are substantially common to container 1, the same reference numerals will be used and detailed descriptions will be omitted. Figure 8(a) shows the lid 3A in the open state, and Figure 8(b) shows the opening M closed with the lid 3A.

[0044] Container 1A comprises a container body 2A having a substantially circular opening M in plan view, a lid 3A that closes the opening M, and a hinge portion 4 connecting the container body 2A and the lid 3A. The container body 2A has a body-side flange 5A provided along the periphery Ma of the opening M, and the lid 3A has a lid-side flange 6A that is stacked on the body-side flange 5A. The joint portion 13A is provided in the stacked region A between the body-side flange 5A and the lid-side flange 6A.

[0045] A first rib 71A is provided on the main body flange 5A. The first rib 71A is provided so as to protrude from the main body side laminated outer surface 5b of the main body flange 5A. Note that in Figure 8(a), for convenience, the first rib 71A is shown from the main body side laminated inner surface 5a of the main body flange 5A. The first rib 71A is provided in the laminated region A of the main body flange 5A and the lid flange 6A. The first rib 71A is positioned between the joint 13 and the opening M and extends along the periphery Ma of the opening M.

[0046] A third rib 81A is provided on the lid-side flange 6A. The third rib 81A is provided so as to protrude from the outer laminated surface 5b on the body side of the lid-side flange 6A. In Figure 8(a), for convenience, the third rib 81A is shown from the inner laminated surface 6a on the lid side of the lid-side flange 6A. The third rib 81A is provided in the laminated region A of the body-side flange 5A and the lid-side flange 6A. When the lid 3 is closed, the third rib 81A is positioned between the joint 13 and the opening M and extends along the periphery Ma of the opening M. In this embodiment, reinforcing ribs are not provided on the body-side flange 5A and the lid-side flange 6A, but reinforcing ribs connected to the first rib 71A or the third rib 81A can be provided on either one or both.

[0047] The lid-side flange 6A includes a first flange portion 61 that curves and extends along the periphery Ma of the opening M, a second flange portion 62 that curves and extends along the periphery Ma of the opening M, and a knob portion 63 positioned between the first flange portion 61 and the second flange portion 62. The knob portion 63 is positioned opposite the hinge portion 4. One end of the first flange portion 61 is connected to the knob portion 63, and the other end reaches the hinge portion 4 and is connected to the second flange portion 62. One end of the second flange portion 62 is connected to the knob portion 63, and the other end reaches the hinge portion 4 and is connected to the first flange portion 61. A third rib 81A, which functions as a damming rib, is provided on the first flange portion 61 and the second flange portion 62.

[0048] In the container 1A, when the lid 3A is open, i.e., before joining, the main body flange 5 has a planned stacking region Ax, and the lid flange 6 has a planned stacking region Ay. A first rib 71A is provided in the planned stacking region Ax so as to follow the periphery Ma of the opening M, and a first rib 71A is provided in the planned stacking region Ay so as to follow the periphery Ma of the opening M when the lid 3A is closed. In addition, a second rib 72A is provided in the planned stacking region Ax, connected to the first rib 71A, and a fourth rib 82A is provided in the planned stacking region Ay, connected to the third rib 81A.

[0049] Next, with reference to Figure 9, a container 1B according to the third embodiment will be described. Container 1B has a structure common to container 1 according to the first embodiment. Therefore, in the following description, the differences will be the focus, and the same reference numerals will be used for structures common to container 1, and detailed explanations will be omitted. In Figure 9(a), for convenience, the first rib 71, second rib 72, third rib 81, and fourth rib 82 are shown from the inner surface 5a of the main body side and the inner surface 6a of the lid side.

[0050] Container 1B comprises a container body 2B having an opening M, a lid 3B that closes the opening M, and a hinge portion 4 connecting the container body 2B and the lid 3B. The container body 2B and the lid 3B are substantially the same shape. In other words, it can be considered to have two container parts of the same shape, in which case one container part that contains food, etc., becomes the container body 2B and the other becomes the lid 3B. Even when no food, etc. is contained, if one can be conveniently designated as the container body 2B, the other is the lid 3B. In this embodiment, the container part on the left shown in Figure 9 is the container body 2B, and the container part on the right is the lid 3B.

[0051] The container body 2B is provided with a body-side flange 5B, and the lid 3B is provided with a lid-side flange 6B. The body-side flange 5B is provided with a rib structure 7 that protrudes from the outer surface 5b of the laminated body. The rib structure 7 comprises a plurality of first ribs 71 provided along the periphery Ma of the opening M, and a plurality of second ribs 72 provided connected to the first ribs 71. The second ribs 72 are an example of reinforcing ribs that prevent tearing when opening. The first ribs 71 are an example of damming ribs that prevent the propagation of tearing when a tear occurs. Although not shown in the illustration, the region formed by the lamination of the body-side flange 5B and the lid-side flange 6B is the laminated region A, and the first ribs 71 and the second ribs 72 are formed in positions within the laminated region A.

[0052] The lid-side flange 6B is provided with a rib structure 8 that protrudes from the outer surface 6b of the lid-side laminate. The rib structure 8 includes a plurality of third ribs 81 provided along the periphery Ma of the opening M when the lid 3 is closed, and a plurality of fourth ribs 82 provided connected to the third ribs 81. The fourth ribs 82 are an example of reinforcing ribs that prevent tearing when opening. The third ribs 81 are an example of damming ribs that prevent the propagation of tearing if it occurs. Although not shown in the figures, the region formed by the lamination of the main body-side flange 5B and the lid-side flange 6B is the laminate region A, and the third ribs 81 and fourth ribs 82 are formed in positions within the laminate region A.

[0053] In the container 1B, with the lid 3B open, i.e., before joining, the main body flange 5B has a planned stacking region Ax, and the lid flange 6B has a planned stacking region Ay. A first rib 71 is provided in the planned stacking region Ax so as to follow the periphery Ma of the opening M, and a third rib 81 is provided in the planned stacking region Ay so as to follow the periphery Ma of the opening M when the lid 3 is closed. Furthermore, a second rib 72 is provided in the planned stacking region Ax connected to the first rib 71, and a fourth rib 82 is provided in the planned stacking region Ay connected to the third rib 81.

[0054] Next, the function and effect of containers 1, 1A, and 1B will be explained. Containers 1, 1A, and 1B are equipped with body-side flanges 5, 5A, and 5B and lid-side flanges 6, 6A, and 6B. Joints 13 and 13A are provided in the stacked region A between the body-side flanges 5, 5A, and 5B and the lid-side flanges 6, 6A, and 6B. First ribs 71, 71A and third ribs 81, 81A, which function as damming ribs, are provided in the stacked region A. The first ribs 71, 71A and third ribs 81, 81A are positioned between the joints 13, 13B and the opening M, and are provided along the periphery Ma of the opening M. In other words, even if a tear occurs when opening the lid 3 from the container body 2, the propagation of the tear is blocked by the first ribs 71, 71A or the third ribs 81, 81A before reaching the opening M, and does not reach the opening M. As a result, the expansion of damage can be prevented.

[0055] Furthermore, since the first ribs 71 and 71A are provided on the main body side flanges 5 and 5A, the propagation of cracks that occur on the main body side flanges 5 and 5A can be prevented by the first ribs 71 and 71A. Also, since the third ribs 81 and 81A are provided on the lid side flanges 6 and 6A, the propagation of cracks that occur on the lid side flanges 6 and 6A can be prevented by the third ribs 81 and 81A.

[0056] Furthermore, the third ribs 81 and 81A are provided to protrude from the outer surface 6b of the lid-side laminate, and the first ribs 71 and 71A are provided to protrude from the outer surface 5b of the main body-side laminate. In other words, the bonding between the inner surface 6a of the lid-side laminate and the inner surface 5a of the main body-side laminate is less affected, which is advantageous in terms of bonding performance.

[0057] Furthermore, containers 1 and 1B are equipped with second ribs 72 and fourth ribs 82 that function as reinforcing ribs. By providing multiple second ribs 72 or fourth ribs 82, it becomes easier to prevent tearing when opening the lid 3.

[0058] Furthermore, the lid-side flange 6B of the container 1B according to the second embodiment includes a first flange portion 61, a second flange portion 62, and a handle portion 63. The handle portion 63 is positioned between the first flange portion 61 and the second flange portion 62. The third rib 81A is provided on both the first flange portion 61 and the second flange portion 62. Therefore, even if a tear occurs when the lid 3 is pulled away from the container body 2 by grasping the handle portion 63, the tear is prevented by the third rib 81 provided on both the first flange portion 61 and the second flange portion 62. As a result, the propagation of the tear caused by pulling at the handle portion 63 is suppressed, and the expansion of damage can be prevented.

[0059] Furthermore, the containers 1, 1A, and 1B with the lid 3 open, that is, the containers 1, 1A, and 1B before joining, are equipped with a body-side flange 5 and a lid-side flange 6. The body-side flange 5 is equipped with a planned stacking region Ax that will be stacked on the lid-side flange 6, and the lid-side flange 6 is equipped with a planned stacking region Ay that will be stacked on the body-side flange 5. The planned stacking region Ax is provided with first ribs 71, 71A that follow the periphery Ma of the opening M, and the planned stacking region Ay is provided with third ribs 81, 81A that follow the periphery Ma of the opening M when the lid 3 is closed. For example, the body-side flange 5 and the lid-side flange 6 are joined in the planned stacking regions Ax and Ay, and the first ribs 71, 71A and the third ribs 81, 81A are positioned between the joint 13 and the opening M. In this case, even if a tear occurs when opening the lid 3 from the container body 2, the propagation of the tear is blocked by the first ribs 71, 71A and the third ribs 81, 81A before it reaches the opening M, and does not reach the opening M. As a result, the expansion of the damage can be prevented.

[0060] Furthermore, the containers 1, 1A, and 1B described above can be formed from, for example, stretched polystyrene sheets. When polystyrene sheets are used, a good balance of properties such as transparency, rigidity, and heat resistance is achieved. On the other hand, stretched polystyrene sheets are rigid and therefore prone to cracking, so preventing the propagation of cracks is highly beneficial. [Examples]

[0061] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In each example and comparative example, a sample of the container was prepared and its openability was evaluated.

[0062] (Example 1) The container according to Example 1 was basically formed based on the container according to the first embodiment, except that reinforcing ribs were not provided on the lid-side flange. The container according to Example 1 was formed by vacuum forming a polystyrene sheet. The container comprises a container body having an opening, a lid that closes the opening, and a joint that joins the container body and the lid. The container body has a body-side flange provided along the periphery of the opening, and the lid has a lid-side flange laminated on the body-side flange. The joint is provided in the laminated region between the body-side flange and the lid-side flange. In Example 1, damming ribs were provided on both the body-side flange and the lid-side flange. In Example 1, reinforcing ribs were provided on the body-side flange, but not on the lid-side flange.

[0063] (Example 2) The container according to Example 2 was formed based on the container according to the first embodiment. In other words, it had the same structure as Example 1, except that reinforcing ribs were provided on both the main body side flange and the lid side flange.

[0064] (Comparative Example 1) The container in Comparative Example 1 had the same structure as in Example 1, except that it did not have damming ribs and reinforcing ribs.

[0065] Multiple containers according to Example 1 were prepared and opened by peeling the lids off the container bodies. Multiple containers according to Example 2 were prepared and opened by peeling the lids off the container bodies. Multiple containers according to Comparative Example 1 were prepared and opened by peeling the lids off the container bodies. As a result, as shown in Table 1, there was no effect on the jointability of Example 1 and Example 2 compared to Comparative Example 1, and good jointability was confirmed. In other words, it was confirmed that the provision of damming ribs and reinforcing ribs does not negatively affect the jointability.

[0066] In the case of the container according to Example 1, even if a tear occurred in the lid-side flange when the lid was opened, the propagation of the tear was suppressed by the damming rib, so the tear prevention performance was evaluated as "good". In the case of the container according to Example 2, even if a tear occurred in either the lid-side flange or the container-side flange, the propagation of the tear was suppressed by the damming rib, so the tear prevention performance was evaluated as "excellent". On the other hand, in the case of the container according to Comparative Example 1, the propagation of the tear that occurred when the lid was opened could not be suppressed, so the tear prevention performance was evaluated as "poor".

[0067] [Table 1]

[0068] Although the present invention has been described above based on embodiments and examples, the present invention is not limited to the above embodiments and examples, and other forms are also possible. For example, reinforcing ribs may not be provided on both the lid-side flange and the body-side flange, and only damming ribs may be provided on one or both. Furthermore, in each of the above embodiments, examples were given of damming ribs and reinforcing ribs being provided so as to protrude from the outer surface of the body-side laminate, or so as to protrude from the outer surface of the lid-side laminate, but for example, they can also be provided so as to protrude from the inner surface of the body-side laminate or the inner surface of the lid-side laminate, avoiding the joint. [Explanation of Symbols]

[0069] 1,1A,1B...Container, 2,2A,2B...Container body, 3,3A,3B...Lid, 5,5A,5B...Body side flange, 5a...Body side laminated inner surface, 5b...Body side laminated outer surface, 6,6A,6B...Lid side flange, 6a...Lid side laminated inner surface, 6b...Lid side laminated outer surface, 13,13A,13B...Joint, 61...First flange piece, 62...Second flange piece, 63...Tap, 71,71A...First rib (damming rib), 72,72A...Second rib (reinforcement rib), 81,81A...Third rib (damming rib), 82,82A...Fourth rib (reinforcement rib), A...Laminated area, Ay...Laminated area, Ax...Laminated area, M...Opening, Ma...Periphery.

Claims

1. A container body having an opening, A lid that closes the aforementioned opening, The container body and the lid are joined by melting, The container body is provided with a body-side flange along the periphery of the opening, The lid comprises a lid-side flange that is stacked on the main body-side flange, The joint portion is provided in the stacked region between the main body side flange and the lid side flange. The laminated region is provided with a damming rib positioned between the joint and the opening, and along the periphery of the opening. The damming rib is provided on at least one of the main body side flange and the lid side flange. A container in which the main body side flange and the lid side flange are spaced apart from each other in the aforementioned damming rib.

2. The container according to claim 1, wherein the damming rib is provided with a recessed structure that is spaced apart from each other between the main body side flange and the lid side flange.

3. The aforementioned damming ribs are provided on both the lid-side flange and the body-side flange. The damming rib of the lid-side flange protrudes in a direction away from the main body-side flange. The container according to claim 1, wherein the damming rib of the main body side flange protrudes in a direction away from the lid side flange.

4. The lid-side flange comprises a lid-side laminated inner surface facing the body-side flange and a lid-side laminated outer surface opposite to the lid-side laminated inner surface, The main body side flange comprises a main body side laminated inner surface facing the lid side flange, and a main body side laminated outer surface opposite to the main body side laminated inner surface. The container according to any one of claims 1 to 3, wherein the damming rib is provided so as to protrude from at least one of the outer surface of the lid-side laminate and the outer surface of the body-side laminate.

5. The container according to any one of claims 1 to 4, wherein the lid-side flange and the body-side flange are provided with reinforcing ribs connected to the damming ribs.

6. The lid-side flange comprises a first flange portion extending along the periphery of the opening, a second flange portion extending along the periphery of the opening, and a handle portion positioned between the first flange portion and the second flange portion. The container according to any one of claims 1 to 5, wherein the damming rib is provided on the first flange portion and the second flange portion.

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