JP7803573B2 - Container body of packaging container - Google Patents

Description

The present invention relates to a lid or container body for a packaging container made of a resin sheet, suitable for stacking.

Boxed lunches, side dishes, salads, noodles, etc. are often packed in packaging containers made of thin plastic sheets and stacked on display in supermarkets, convenience stores, and other stores.
Such packaging containers are made of thin resin sheets and are designed to have sufficient rigidity to prevent deformation even when stacked.

For example, Patent Document 1 below discloses a packaging container that comprises a container body and a lid, and in which a recess is formed on the top surface of the lid to accommodate a protrusion formed on the bottom surface of the container body, allowing the container body to be stacked in multiple layers so that the protrusion on the container body fits into the recess in the lid. The packaging container is characterized in that a bent portion consisting of a protrusion that protrudes into the lid is formed around the periphery of the recess in the lid, making the lid less likely to be crushed even when stacked in multiple layers.

JP 2010-52789 A

As disclosed in Patent Document 1 above, a preferred embodiment of the packaging container is that ribs are formed at appropriate intervals in the circumferential direction on the peripheral wall extending downward from the outer periphery of the top surface of the lid, and it is common to provide ribs to increase the rigidity of the peripheral wall.
However, providing many ribs on the peripheral wall obstructs the view and makes it difficult to see the contents stored inside. In particular, when the containers are stacked, the top surface is covered and the only visible area inside is the peripheral wall, so providing many ribs here can make it difficult to see what the contents are.

The object of the present invention is to provide a lid for a packaging container that is rigid enough to be stacked without the need for numerous ribs or the like on the peripheral wall, and also to provide a container body with a similar structure.

The lid body of a packaging container in a reference form is a lid body of a packaging container made of a resin sheet having a top surface portion and a side wall portion extending downward from its periphery, and is characterized in that the connecting portion between the top surface portion and the side wall portion is a concave portion that is recessed toward the inside of the lid body, and the concave portion is provided along all or part of the circumferential direction of the lid body.

In this way, by creating a recessed portion at the connecting portion between the top surface and side wall of a thin-walled packaging container lid made from a resin sheet, the recessed portion bends even when another packaging container is placed on the top surface, absorbing external forces appropriately, making it less likely that the side wall will be crushed even when stacked.

In the above embodiment, the recessed portion may be curved in cross section.
This allows the recessed portion to more easily absorb external forces and to more easily restore its original shape due to its elasticity.

In the above embodiment, the top surface and the side wall can each be flat.
By doing so, if the lid is made transparent, the inside of the container can be easily seen because there are no ribs on the top surface or side wall. When the containers are stacked, the contents can be seen through the side wall.

Furthermore, the container body of a packaging container of one embodiment of the present invention has a bottom surface portion and a side wall portion extending upward from the periphery of the bottom surface portion, and is made of a resin sheet, wherein the connecting portion between the bottom surface portion and the side wall portion is a concave portion recessed toward the inside of the body, the concave portion is provided around all or part of the circumference of the body, and the radius of curvature on the surface side of a first connecting portion which is the connecting portion between the bottom surface portion and the concave portion and a second connecting portion which is the connecting portion between the side wall surface portion and the concave portion are formed so that the radius of curvature of the surface side is 1.0 mm or less.
Even in this case, as with the lid body, the recessed portions bend even when stacked and absorb external forces appropriately, making it difficult for the side walls and the like to be crushed.

1 is a perspective view of a lid of a packaging container according to an embodiment of the present invention. 2 is a side view of the cover of FIG. 1 as viewed from the longitudinal side wall portion side. FIG. 2 is a side view of the cover of FIG. 1 as viewed from the shorter side wall portion side. FIG. FIG. 2 is a plan view of the lid of FIG. 1 . 2 is a partially enlarged end view of the cover shown in FIG. 1 with a side wall portion cut away. FIG. 2 is a perspective view showing an example of a container body fitted to the lid body shown in FIG. 1 . FIG. 2 is a diagram illustrating a state in which the top surface of the lid is pressed down.

Below, one embodiment of the lid for a packaging container of the present invention will be described with reference to the drawings.

As shown in Figure 1, the lid 1 of a packaging container according to one embodiment of the present invention comprises a top surface 11, a side wall 12, and a recessed portion 13.

2 to 4, the top surface 11 is formed as a horizontal surface that is a flat, rectangular surface in a plan view. By making it a flat surface, it is easy to stack the containers, and if it is made transparent, it is easy to see inside.
In this embodiment, the shape is rectangular in plan view, but is not limited to this, and may be rectangular in plan view such as a square or rhombus, polygonal in plan view such as a hexagon or octagon, circular, oval, etc. Also, in this embodiment, the surface is flat, but the shape may be a curved surface (dome) that bulges near the center, a curved arch shape in side view, or a wavy shape with repeated concave and convex shapes.

5, the side wall portion 12 is formed as a flat surface that slopes downward from the periphery of the top surface portion 11. By making the surface flat, if the side wall portion 12 is made transparent, the inside can be easily seen.
In this embodiment, the surface is an inclined flat surface, but the present invention is not limited to this, and the surface may be a drooping surface, a convex curved surface, or a concave curved surface.
The angle (θ in FIG. 5) between the top surface 11 and the side wall 12 is not particularly limited, but is preferably 90° or more, with the upper limit being preferably 110° or less.

The recessed portion 13 is formed around the entire circumferential circumference by recessing the area near the connection between the top surface 11 and the side wall 12. In this embodiment, the recessed portion 13 is formed around the entire circumferential circumference of the lid body. However, this is not limited to this. The recessed portion 13 may be formed only in a portion and intermittently. It is preferable that the other portions be bent at right or obtuse angles. Providing the recessed portion 13 around the entire circumferential circumference maximizes the external force absorption function, but may reduce the rigidity of the lid body 1. Furthermore, forming the recessed portion 13 in a square shape rather than a square shape can increase the rigidity of the lid body 1. Furthermore, a square shape may be preferable from a design perspective. It is preferable to design the lid body 1 while balancing the external force absorption and rigidity, taking design into consideration. From this perspective, it is preferable to form the recessed portion 13 over at least about half, particularly at least about 70%, and even more preferably at least about 80% of the entire circumferential length around the connection between the top surface 11 and the side wall 12.
The cross section of the recessed portion 13 is curved. This cross section does not have to be an arc shape with a constant radius as long as it is curved. By doing so, the load on the top surface portion 11 can be absorbed by the recessed portion 13, making it easier to restore its original shape.
In this embodiment, the cross section is curved, but this is not limiting, and it is sufficient that the cross section is recessed, and it may be recessed in a broken line shape.

The first connecting portion 14, which is the connecting portion between the top surface portion 11 and the recessed portion 13, is not particularly limited, but it is preferable that the radius of curvature R on the surface side of the lid 1 is 1.0 mm or less. Furthermore, the second connecting portion 15, which is the connecting portion between the side wall portion 12 and the recessed portion 13, is not particularly limited, but it is preferable that the radius of curvature R on the surface side of the lid 1 is 1.0 mm or less. This allows the recessed portion 13 to efficiently absorb loads.

The recessed portion 13 is preferably formed with a constant width, and is preferably formed narrow. More specifically, as shown in Figure 2, the width W of the recessed portion 13 in a plan view is preferably 8% or less of the width W' of the top surface portion 11 and recessed portion 13. If the width is too wide, the recessed portion 13 will bend too much, causing the top surface portion 11 to sink significantly when stacked. Note that width W' indicates the maximum width of the top surface portion 11 and recessed portion 13.

A flange 16 is formed at the lower end of the side wall 12, facing outward from the lid body, and a fitting portion 17 is provided at the tip of the flange 16 as a hanging surface.
The fitting portion 17 is formed with engagement portions 18 that protrude toward the inside of the lid body so that it can fit into the container body 2. The engagement portions 18 are formed intermittently with an appropriate length in the circumferential direction. The lid body 1 is provided with tongue-shaped tabs 19 at its four corners.

The container body 2 to be covered with the lid body 1 may have any shape as long as it is designed so that the lid body 1 can be covered.
As shown in Figure 6, the container body 2 is a so-called "hakama" type, and has a rectangular shape in a plan view and a side wall portion 22 that rises upward from the periphery of a horizontal bottom surface portion 21.The upper end of the wall portion 22 is folded back to the outside of the body to form a fitting portion 23, and the lower end of the fitting portion 23 extends downward to form legs 24.

The mating portion 23 is designed so that the mating portion 17 of the lid 1 can be fitted onto it from the outside, and has a locking portion 25 formed around the entire periphery that protrudes outward from the main body, with which the engaging portion 18 can be engaged.
In this embodiment, the lid body 1 is configured to be externally fitted to the container body 2, but this is not limited to this and may be a fitting structure such as internal fitting or internal/external fitting, or a structure in which the lid body 1 is placed on the container body 2.

A packaging container consisting of a lid 1 and a container body 2 can hold, for example, food items, and more specifically, bento boxes, side dishes, sushi, salads, etc.

The lid 1 and the container body 2 can be manufactured by thermoforming a synthetic resin sheet, although there are no particular limitations on the material. The synthetic resin sheet may be either a non-foamed resin sheet or a foamed resin sheet, with a non-foamed resin sheet being preferred.
In the case of a non-foamed resin sheet, it is preferable to use a so-called thin resin sheet, specifically a sheet having a thickness in the range of 0.1 mm to 2.0 mm, particularly 0.2 mm to 1.2 mm.
In the case of a foamed resin sheet, it is preferable to use a sheet having a thickness of 0.5 mm to 4.0 mm, particularly 0.7 mm to 2.2 mm, and it is also preferable to use a foamed resin sheet having an expansion ratio of 1.05 to 20.0 times, particularly 1.5 to 15.0 times.

Examples of non-foamed resin sheets that can be used include thermoplastic resin sheets, such as polyolefin resin sheets (e.g., polyethylene resin sheets, polypropylene resin sheets), and polyester resin sheets (e.g., polystyrene resin sheets, polyethylene terephthalate resin sheets, and heat-resistant modified polyethylene terephthalate resin sheets). Materials that can withstand heating in a microwave oven, such as heat-resistant polystyrene resin sheets, polypropylene resin sheets, and heat-resistant modified polyethylene terephthalate resin sheets, can also be used.

Examples of foamed resin sheets that can be used include foamed polyolefin resin sheets, foamed polystyrene resin sheets, and foamed polyester resin sheets such as foamed polyethylene terephthalate.
A laminated sheet obtained by laminating synthetic resin sheets can also be used. Examples of the laminated sheet include a laminated sheet obtained by thermally laminating a resin film onto a non-foamed resin sheet or a foamed resin sheet, a laminated sheet obtained by a co-extrusion method, and a laminated sheet obtained by an extrusion lamination method.

Examples of thermoforming include vacuum forming, pressure forming, vacuum pressure forming, and hot plate forming. When thermoforming the lid 1, it is preferable to use a male mold. Using a male mold makes it easier to increase the thickness of the top surface 11 and improve its rigidity.

The lid 1 and container body 2 may be colored, such as black or white, but are preferably transparent or translucent so that the interior can be seen. In particular, it is preferable that the lid 1 be transparent or translucent, and the container body 2 be opaque, such as black. Furthermore, the surface of the lid 1 may be printed or engraved with letters, pictures, etc., to the extent that visibility is not impaired, and ribs may be provided for reinforcement or textured for anti-slip properties. Stacking protrusions S, which bulge out in the shape of a rectangular parallelepiped, may also be provided to prevent the lids 1 from sticking together when stacked.

Although not shown, as another embodiment of the present invention, a structure in which a recessed portion is provided in the container body can also be used.
This container body can have a structure in which the lid 1 is turned upside down, and more specifically, it has side walls extending upward from the periphery of the flat bottom, and the connecting portion between the bottom and side walls can be formed as a recessed portion recessed toward the inside of the body. In this case, too, it is preferable that the recessed portion be curved in cross section, and that the bottom and side walls each be flat.
In such a container body, the recessed portion can absorb the load on the container body, making the side wall portion less likely to be crushed.

The lid 1 and container body 2 may be integrally connected by a hinge to form a so-called food pack.

The packaging container of this embodiment can be used, for example, by placing food in the container body 2 and then fitting the lid 1.

When these packaging containers are stacked, even if the top surface 11 is pressed down, the recessed portion 13 bends as shown in Figure 7, reducing the load on the side wall 12 and making it less likely for the side wall 12 to be crushed. This means that there is no need to provide ribs or other reinforcing features on the side wall 12. In particular, if the lid 1 is transparent, there are no ribs or other features on the side wall 12 even when stacked, providing good visibility and allowing the contents inside to be checked.

When the load on the top surface 11 is removed, the elastic force of the recessed portion 13 allows it to return to its original shape.

The configuration aspects of the above-described embodiments are not intended to limit the scope of the present invention; modifications are possible as long as the technical objectives are shared, and the present invention includes such modifications.

1 Lid 11 Top surface 12 Side wall 13 Recessed portion 14 First connecting portion 15 Second connecting portion 16 Flange portion 17 Fitting portion 18 Engagement portion 19 Handle portion 2 Container body 21 Bottom surface 22 Side wall 23 Fitted portion 24 Leg portion 25 Locking portion S Stacking protrusion

Claims (5)

A container body of a packaging container made of a resin sheet, having a bottom surface and a side wall portion extending upward from the periphery of the bottom surface, wherein the connecting portion between the bottom surface and the side wall portion is a concave portion recessed toward the inside of the body, and the concave portion is provided along all or part of the circumference of the body, and the container body of the packaging container is formed so that the radius of curvature on the surface side of a first connecting portion which is the connecting portion between the bottom surface and the concave portion and a second connecting portion which is the connecting portion between the side wall surface and the concave portion is 1.0 mm or less. 2. The container body of a packaging container according to claim 1 , wherein the recessed portion has a curved cross section. 3. The container body of a packaging container according to claim 1, wherein the bottom surface and the side wall are each flat. A packaging container using the container body of the packaging container according to any one of claims 1 to 3 . A method for manufacturing a container body of a packaging container, which comprises manufacturing the container body of the packaging container according to any one of claims 1 to 3 using a male mold.