Packaging container

Abstract

To provide a packaging container made of a synthetic resin sheet, particularly a flat dish-type packaging container not having a height of a side wall, which is thin walled part but hardly deforms when a content is placed on it or when it is lifted up.SOLUTION: A packaging container 1 has an outer edge having a quadrangular shape in a plane view made of a synthetic resin sheet, and has a placing surface part 21a formed in a horizontal plane shape on a bottom surface 21, wherein the placing surface part 21a is provided with at least one recessed grooved rib 25 recessed in an X-shape where two straight lines intersect, and the recessed grooved rib 25 is arranged at each corner part 11 of the outer edge at a position where a virtual line W extending one or both of the straight lines forming the recessed grooved rib 25 passes through a range of the corner part 11 in a plane view.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a packaging container made of a synthetic resin sheet. [Background technology]

[0002] In supermarkets, convenience stores, and other retailers, bento boxes, fruits and vegetables, fresh fish, side dishes, desserts, sushi, and other foods are packaged in packaging containers made from thin-walled synthetic resin sheets and displayed in stores. In consideration of the environment and to conserve resources, these packaging containers are being made even thinner.

[0003] As packaging containers become thinner, they lose strength and rigidity, increasing the risk of them being crushed when stacked or deformed when lifted. In particular, packaging containers with thin side walls (such as flat or shallow dish-type containers) may have their bottoms bent or twisted when lifted, causing the contents to shift.

[0004] Therefore, in packaging containers made of thin synthetic resin sheets, recessed grooves or protruding ribs are provided on the bottom and side walls to increase strength and rigidity. For example, containers have been developed that are less likely to deform by providing a large number of ribs on the bottom wall or side wall (see Patent Documents 1 and 2 below).

[0005] In addition, a packaging container has been developed that has been designed with an improved arrangement of ribs on the bottom surface, and has deep grooves extending in the longitudinal direction of the bottom surface and shallow grooves extending in the lateral direction of the bottom surface that are shallower than the deep grooves, so that the shallow grooves do not intersect with the deep grooves, making it less likely to bend or twist when food is placed on it (see Patent Document 3 below). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-108820 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-184983 [Patent Document 3] Japanese Patent Publication No. 2023-178553 Summary of the Invention [Problem to be solved by the invention]

[0007] As synthetic resin sheets for packaging containers become thinner, research and development is being conducted to ensure the strength and rigidity of packaging containers so that they are less likely to deform. The inventors have thoroughly studied the shape and arrangement of the ribs and have developed a packaging container that is less likely to warp or twist, even if it is a packaging container, particularly a flat or shallow dish-type container with low height (a container with a low side wall height).

[0008] Therefore, an object of the present invention is to provide a packaging container made of a synthetic resin sheet, particularly a flat dish-shaped packaging container with low side walls, which is thin but does not easily deform when contents are placed on it or when it is lifted. [Means for solving the problem]

[0009] One form of packaging container of the present invention is a packaging container made of a synthetic resin sheet and having an outer edge that is rectangular in plan view, and has a mounting surface portion formed in a horizontal plane on the bottom surface, and is provided with at least one grooved rib that is recessed in an X-shape where two straight lines intersect on the mounting surface portion, and the grooved rib is arranged at each corner portion of the outer edge at a position where an imaginary line extending one of the straight lines that forms the grooved rib passes through the range of the corner portion in plan view.

[0010] The packaging container of the above embodiment may include at least two of the recessed groove ribs, and a linearly bulging convex rib may be provided between the recessed groove ribs.

[0011] In the packaging container of the above form, it is preferable that the packaging container has a peripheral wall portion provided around the packaging container and a flange portion extending from the upper end thereof to the outside of the container, and that the boundary between the peripheral wall portion and the flange portion has a bent portion with a cross section that is recessed in a square-bent shape.

[0012] In the packaging container of the above aspect, the placement surface portion and the upper end portion of the peripheral wall portion may be at substantially the same height.

[0013] In the packaging container of the above embodiment, the convex rib may be formed in a diamond shape in a plan view.

[0014] The packaging container of the above-mentioned form has an X-shaped groove rib on the placing surface of the bottom part, and the groove rib is arranged in a position where an imaginary line extending from the straight line forming the groove rib passes through the range of the corner part of the outer edge, so that the groove rib and the corner part work together to make it less likely for the bottom part to deform, such as bending or twisting. Furthermore, by providing convex ribs or bent portions, deformation can be made even less likely to occur, particularly in flat or shallow dish-type packaging containers in which the placing surface and the upper end of the peripheral wall are at approximately the same height. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a packaging container of one embodiment of the present invention in an open state. [Figure 2] 2 is a front view of a container body and a lid body of the packaging container of FIG. 1. FIG. [Figure 3] 2 is a side view of a container body and a lid body of the packaging container of FIG. 1. FIG. [Figure 4] FIG. 2 is a plan view of a container body of the packaging container of FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. [Figure 6] FIG. 6 is an enlarged view of part D in FIG. 5. [Figure 7] FIG. 5 is a cross-sectional view taken along line BB in FIG. 4. [Figure 8] FIG. 5 is a cross-sectional view taken along line CC in FIG. 4. [Figure 9] 10 is a diagram for explaining the relationship in height between the mounting surface portion and the peripheral wall portion. FIG. [Figure 10] 10A and 10B are diagrams for explaining the positional relationship between a recessed groove rib and a corner portion. [Figure 11] FIG. 2 is a plan view of a first modified example of the packaging container of the present invention. [Figure 12] FIG. 10 is a plan view of a second modified example of the packaging container of the present invention. [Figure 13] FIG. 10 is a plan view of a third modified example of the packaging container of the present invention. [Figure 14] FIG. 10 is a plan view of a fourth modified example of the packaging container of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a packaging container according to one embodiment of the present invention will be described with reference to the drawings.

[0017] A packaging container 1 according to one embodiment of the present invention includes a container body 2 and a lid body 3 that covers the container body 2, as shown in FIGS.

[0018] Packaging container 1 comprises a container body 2 and a lid 3 that fits over it, and in this embodiment, container body 2 is rectangular in shape when viewed from above, and lid 3 is formed to have a horizontally elongated rectangular parallelepiped shape when fitted over container body 2. Packaging container 1 can be sized to have a height of approximately 30 mm to 70 mm, a length of 200 mm to 300 mm, and a width of 70 mm to 150 mm, although there are no particular limitations on the size, and is suitable for storing food and beverages such as boxed lunches, bread, fruits and vegetables, fresh fish, side dishes, desserts, and sushi.

[0019] In this embodiment, the packaging container 1 is provided with a lid body 3, but the packaging container 1 may also have only the container body 2 without the lid body 3, and is not limited to the above shape. For example, when viewed from above, it may have a quadrangular shape such as a square, rectangle, parallelogram, or trapezoid, and it is preferable that the corners are rounded or chamfered.

[0020] As shown in FIG. 4 or 5, the container body 2 is in the shape of a horizontally long rectangular flat plate, and each corner 11 of the outer edge is formed into a rounded corner. 1, the device includes a bottom surface 21 made up of a mounting surface 21a and a peripheral trench 21b, a peripheral wall 22 rising upward from the outer periphery of the bottom surface 21, and a flange 23 extending outward from the upper end of the peripheral wall 22. Part or all of the peripheral trench 21b also serves as leg 24.

[0021] As shown in Figure 4 or Figure 5, the bottom surface portion 21 consists of a mounting surface portion 21a which is a horizontal rectangular surface in a plan view on which contents can be placed, and a groove-shaped surrounding trench portion 21b provided around the mounting surface portion 21a, and groove ribs 25 are provided at predetermined positions on the mounting surface portion 21a. The recessed groove rib 25 is formed by recessing the mounting surface portion 21a into an X-shape formed by the intersection of two straight lines. In this embodiment, three such recessed grooves are provided at equal intervals in the horizontal direction. The straight lines forming the recessed groove rib 25 are not particularly limited, but may be formed as semicircular or U-shaped grooves, square grooves with a U-shape or an inverted trapezoidal shape, or V-shaped grooves in cross section. In this embodiment, the recessed groove rib 25 is formed as a square groove with a width of 2 to 3 mm relative to a depth of 1 mm. The length, width, and depth of each straight line are determined appropriately according to the size of the container 1. For example, the length may be 20 mm to 70 mm, the width 1 mm to 5 mm, and the depth 0.5 mm to 3 mm. The depth may be constant along the entire length of the straight lines, but it is preferable for the depth to gradually increase from the intersection of the straight lines outward to enhance the rigidity of the container body 2. The angle at which the two straight lines intersect is not particularly limited, but is preferably 120° to 90°, and more preferably approximately 90°.

[0022] Between each of the recessed ribs 25, a protruding rib 26 can be provided. The convex ribs 26 are formed in a linear shape by bulging the mounting surface portion 21a, and in this embodiment, as shown in Fig. 4 or 8, are arranged in the middle positions separating the respective concave ribs 25, and are formed in a long and narrow diamond shape (length 5 to 8 with width 1). The shape of the convex ribs 26 is not particularly limited, and may be a long and narrow rectangle, a long and narrow oval, or an ellipse in a plan view.

[0023] As shown in FIG. 1, 4, or 5, a vertical wall 27 is provided at the outer edge of the mounting surface 21a, i.e., at the boundary with the peripheral trench 21b, to surround the mounting surface 21a. Providing the vertical wall 27 makes it difficult for the container body 2 to deform. The vertical wall 27 may be provided along the entire periphery of the mounting surface 21a, or may be omitted in a portion thereof, forming a cut-out opening 21c. The opening 21c connects the mounting surface 21a and the peripheral trench 21b, allowing liquids such as juices that ooze out when food or the like is placed on the mounting surface 21a to pass through. In this embodiment, as shown in FIG. 4, three pairs of openings 21c are formed facing each other in the front-to-back direction.

[0024] The peripheral trench portion 21b is formed by recessing the outer periphery of the bottom surface portion 21 and also serves as the legs 24 of the container 1. Providing the peripheral trench portion 21b can make the container body 2 less likely to deform. The peripheral trench portion 21b may be formed with the same depth all around, or the depth may be varied, with a shallower bottom portion and a trapezoidal protrusion 21d, as shown in FIG. 1 or 4. By providing the protrusion 21d in the peripheral trench portion 21b with different depths, the container body 2 can be made even less likely to deform than when the entire periphery is the same depth. The protrusion 21d is preferably provided at the position where the opening 21c is provided. Furthermore, it is preferable to form a stepped surface 21e, which is an inclined plane, between the protrusion 21d and the opening 21c, as shown in FIG. 7. As a result, when food or the like is placed on the placing surface portion 21a, the liquid content such as juice that seeps out passes through the opening portion 21c, the stepped surface portion 21e, and the raised portion 21d in this order, and can be collected in the surrounding trench portion 21b.

[0025] As shown in FIG. 1, FIG. 5 or FIG. 6, the surface of the peripheral trench portion 21b positioned on the outside of the main body is a peripheral wall portion 22 that rises upward. The peripheral wall portion 22 is formed in an inclined plane shape that extends upward from the bottom surface portion 22 and widens outward from the main body, and a flange portion 23 that projects outward from the main body is provided at the upper end portion. As shown in FIG. 6, the upper side of the peripheral wall 22 is formed in a stepped shape, and in this embodiment, it is formed in two steps. The corner of the boundary between the peripheral wall 22 and the flange 23 is formed as a bent portion 22a, which is formed in a stepped shape by being recessed with a bent cross section. The provision of the bent portion 22a makes it possible to make the container body 2 less likely to deform. The bent portion 22a is preferably provided around the entire circumference, but may also be provided partially or intermittently. The bent portion 22a is preferably formed to have a width of 0.2 mm to 1.5 mm and a depth of 0.2 mm to 1.5 mm, and the inner radius of the bent portion is preferably 1.0 mm or less, and more preferably 0.5 mm or less.

[0026] In this embodiment, as shown in Figure 6, the flange portion 23 comprises a flat portion 23a that extends horizontally with a constant width, a skirt portion 23b that is an inclined flat surface extending downward from the leading edge of the flat portion 23a, and a small protrusion 23c that protrudes a small width from the lower end of the skirt portion 23b to the outside of the main body.

[0027] The upper end of the peripheral wall 22 (corresponding to the upper surface of the flat portion 23a of the flange 23 in this embodiment) is preferably formed at approximately the same height as the mounting surface 21a. In other words, the packaging container 1 is preferably a flat dish-shaped container in which the peripheral wall 22 is not high relative to the mounting surface 21a, or a shallow dish-shaped container in which the peripheral wall 22 is low relative to the mounting surface 21a. More specifically, as shown in FIG. 9 , the height (Hb) of the peripheral wall 22 and the height (Ha) of the mounting surface 21a preferably satisfy the relationship 0.8Hb≦Ha, and more preferably satisfy the relationship Hb≦Ha≦1.2Hb. Furthermore, the height (Hb) of the peripheral wall 22 and the height (Ha′) of the upright wall 27 preferably satisfy the relationship Ha′≦1.2Hb, and more preferably satisfy the relationship 0.8Hb≦Ha′≦1.2Hb.

[0028] The packaging container 1 has an outer edge (corresponding to the tip of the minute protrusion 23c in this embodiment) that is rectangular with rounded corners 11, and for each corner 11 of this outer edge, an imaginary line extending one of the straight lines forming the recessed groove rib 25 passes through the range of the corner 11 in a plan view. Note that the range of the corner 11 refers to the range between the inflection points where a straight line changes to a curve in the case of a rounded corner 11, and the range between the bending points where the straight line bends in the case of a chamfered corner 11. Furthermore, the imaginary line extending a straight line refers to the center line of that straight line.

[0029] 10, in this embodiment, an imaginary line W extending one straight line of the left-side recessed groove rib 25 passes through the upper left corner 11, and an imaginary line X extending the other straight line passes through the lower left corner 11. Also, an imaginary line Y extending one straight line of the right-side recessed groove rib 25 passes through the upper right corner 11, and an imaginary line Z extending the other straight line passes through the lower right corner 11.

[0030] In this way, by arranging the groove rib 25 at each corner 11 of the outer edge of the packaging container 1 at a position where an imaginary line extending from any of the straight lines forming the groove rib 25 passes through the range of the corner 11 in a plan view, the packaging container 1 is less likely to bend or twist when lifted. This is because, while a flat packaging container is prone to bending inward or outward at the corners when lifted, the provision of the groove rib 25 on the bending line in the packaging container 1 makes the bottom portion 21 less likely to deform.

[0031] As shown in Figures 1 to 3, the lid body 3 is placed over the container body 2 and is formed in the shape of a horizontally elongated trapezoid. It includes a top surface 31, a side wall portion 32 extending downward from the periphery of the top surface 31, a flange portion 33 extending from the lower edge of the side wall portion 32 to the outside of the lid body, and a fitting portion 34 that fits onto the outer edge of the container body 2.

[0032] 1, the top surface 31 has a horizontal surface that is a horizontally elongated rectangle in plan view. The side wall 32 is formed as an inclined plane that slopes downward from the periphery of the top surface 31.

[0033] As shown in Figure 1, in this embodiment, the flange portion 33 comprises a flat portion 33a that extends horizontally at a constant width, a skirt portion 33b that is an inclined flat surface extending downward from the leading edge of the flat portion 33a, and an engaging portion 34 provided on the skirt portion 33b that protrudes inside the lid body 3 and engages with the outer edge of the container body 2. The flat surface portion 33a is arranged to rest on the flat surface portion 23a of the container body 2 when the lid body 3 is fitted to the container body 2. The fitting portion 34 protrudes inward from the lid body 3 and is formed with an appropriate length extending intermittently in the circumferential direction to enable so-called external fitting. In this embodiment, an external fitting structure is used in which the lid body 3 fits into the container body 2 from the outside, but this is not limited to this, and any fitting structure such as an internal fitting structure or an internal / external fitting structure may be used. Also, a structure in which the lid body 3 rests on the container body 2 without fitting may be used.

[0034] An example of a method for manufacturing a packaging container 1 consisting of a container body 2 and a lid 3 will be described below. Although there are no particular limitations on the container body 2 and the lid 3, they can be manufactured by thermoforming a synthetic resin sheet. The synthetic resin sheet may be formed from either a non-foamed resin sheet or a foamed resin sheet, but it is preferable to form the container body 2 and the lid 3 from a thin non-foamed resin sheet.

[0035] In the case of a non-foamed resin sheet, it is preferable to use a sheet having a thickness in the range of 0.1 mm to 2.0 mm, particularly in the range of 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 in the range 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.

[0036] Examples of non-foamed resin sheets that can be used include thermoplastic resin sheets such as polyolefin resin sheets, such as polyethylene resin sheets and polypropylene resin sheets, and polyester resin sheets, such as polystyrene resin sheets, polyethylene terephthalate resin sheets, and heat-resistant modified polyethylene terephthalate resin sheets. Furthermore, 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, may also be used.

[0037] 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.

[0038] Biomass plastics such as biodegradable resins may be used for the non-foamed resin sheet, foamed resin sheet, and laminated sheet. Biomass plastics are polymeric materials obtained by chemical or biological synthesis using renewable organic resources as raw materials. Compared to petroleum-derived resins, biomass plastics can reduce carbon dioxide emissions into the atmosphere, thereby reducing the burden on the environment. Examples of biomass plastics include polylactic acid resin, biomass polyethylene, and biomass polyethylene terephthalate.

[0039] Examples of thermoforming include vacuum forming, pressure forming, vacuum pressure forming, and hot plate forming.

[0040] The container body 2 and the lid body 3 may be colored, such as black or white, but are preferably transparent or semi-transparent so that the inside can be seen. If the container body 2 and the lid body 3 are transparent or semi-transparent, the surfaces thereof may be printed or engraved with letters, pictures, etc., as long as the visibility is not impaired. Furthermore, the flanges 23, 33 may be textured to prevent slipping. Also, the container body 2 and the lid 3 may be provided with stacking protrusions in the shape of a cube or a rectangular parallelepiped at appropriate positions.

[0041] An example of how to use the packaging container 1 will be described below. By placing the contents, such as food, on the mounting surface 21a of the container body 2, placing the lid body 3 over the container body 2, and pressing the lid body 3 from above, the fitting portion 34 fits into the outer edge of the container body 2, and the contents can be packaged in the packaging container 1. To open the packaging container 1, for example, the user may hook the fingertips under the lower end of the skirt portion 33b of the lid body 3 and spread it, release the engagement of the engagement portion 34, and lift the lid body 3.

[0042] As shown in FIG. 4, the packaging container 1 has grooved ribs 25 at appropriate positions on the placement surface 21a, so that the container 1 is less likely to bend, twist or deform when lifted, and the contents are less likely to shift. Furthermore, by providing a plurality of recessed groove ribs 25 and providing convex ribs 26 having a diamond shape in plan view or the like between the recessed groove ribs 25, the bottom surface portion 21 becomes even more resistant to deformation.

[0043] In addition, by providing a bent portion 22a that is recessed in a square shape at the boundary between the peripheral wall portion 22 and the flange portion 23, the container 1 can be made less likely to bend, twist, or deform, making it less likely for the contents contained therein to shift or move.

[0044] The packaging container 1 is particularly suitable as a container in which the height of the placing surface portion 21a and the peripheral wall portion 22 are substantially the same, that is, a flat dish-type or shallow dish-type container.

[0045] In this embodiment, the groove ribs 25 are arranged in three horizontal rows, but this is not limited to this. For example, they can be arranged in two horizontal rows as in the first modified packaging container 1A shown in Figure 11, in two horizontal rows and two vertical rows as in the second modified packaging container 1B shown in Figure 12, or in three horizontal rows and two vertical rows as in the third modified packaging container 1C shown in Figure 13. Also, like a packaging container 1D of a fourth modified example shown in FIG. 14, it is possible to provide the standing wall portion 27 along the entire periphery of the placement surface portion 21a, and not provide the opening portion 21c.

[0046] The configurations of the above-described embodiments are not intended to limit the present invention, and modifications are possible as long as the technical purpose is the same, and the present invention includes such modifications. [Explanation of symbols]

[0047] 1 Packaging container 11 Corner section 2 Container body 21 Bottom part 21a Placement surface section 21b Surrounding trench 21c opening 21d ridge 21e Step surface part 22 Side wall 22a Bend part 23 Flange 23a Flat part 23b Skirt section 23c Micro protrusion 24 Legs 25 Concave rib 26 Convex rib 27 Vertical wall 3 Lid 31 Top section 32 Side wall 33 Flange 33a Flat part 33b Skirt section 34 Fitting part

Claims

1. A packaging container made of a synthetic resin sheet and having a rectangular outer edge in a planar view, the packaging container having a horizontally formed base surface on the bottom, and at least one grooved rib recessed in an X-shape where two straight lines intersect on the base surface, the grooved rib being arranged at each corner of the outer edge such that an imaginary line extending from one of the straight lines forming the grooved rib passes through the area of ​​the corner in a planar view.

2. 2. The packaging container according to claim 1, comprising at least two of said grooved ribs, and a linearly bulging convex rib provided between said grooved ribs.

3. 3. The packaging container according to claim 1, further comprising a peripheral wall portion provided around the packaging container and a flange portion extending from the upper end of the peripheral wall portion to the outside of the container, and a bent portion having a cross section that is recessed in a square-bent shape at the boundary between the peripheral wall portion and the flange portion.

4. The packaging container according to claim 3 , wherein the placement surface and the upper end of the peripheral wall are at substantially the same height.

5. 3. The packaging container according to claim 2, wherein the protruding ribs are formed in a diamond shape in a plan view.

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