JP2023092362A - package for microwave oven - Google Patents

Abstract

To provide a package for a microwave oven, which can suppress the inside of the package from being brought into a decompression state, after the package using a container made of paper materials is heated in the microwave oven.SOLUTION: The package for a microwave oven is provided with a film-shaped lid part and a container sealed with the lid. The container is constituted of paper raw material layers and laminated resin layers made to adhere to the paper raw material layers. The container has a container main body formed in a concave shape which can store contents, an annular flange part provided to extend outward from an upper end of the container main body, and a heat-welded part in which the flange part is heat-welded to the lid part. The heat-welded part is provided across a whole circumference of the flange part. The heat-welded part comprises a vapor discharge part for discharging vapor. With respect to a vapor discharge flange part which is a site at which the vapor discharge part is provided of the flange part, a warpage generation structure configured to generate warpage in the vapor discharge flange part, during heating.SELECTED DRAWING: Figure 1

Description

The present invention relates to a package for microwave ovens.

The package for microwave ovens of Patent Document 1 is configured such that when the internal pressure of the package rises due to heating in the microwave oven, the lid and the flange are separated at the steam discharge part, and the steam is discharged.

JP-A-2008-290738

By the way, it may be desired to use a paper material container in which a paper material layer and a resin layer are laminated as a container for a package for a microwave oven. When the present inventor conducted a heating test in a microwave oven on a package for a microwave oven constructed using a container made of a paper material, a steam flow path was formed as the internal pressure inside the package rose, and the steam flowed properly. It was found that, even though the steam was discharged, the lid and the flange would then come into close contact with each other, closing the steam flow path, and as the package cooled, the inside of the package would become decompressed. . In addition, it has been found that when the inside of the package is decompressed, the resin layer and the paper material layer of the container separate and the resin layer floats up toward the package, which significantly impairs the appearance of the package.

The present invention has been made in view of such circumstances, and a microwave oven that suppresses the inside of the package from becoming decompressed after heating the package using a paper material container in a microwave oven. It provides a package for

According to the present invention, there is provided a microwave package for storing contents in a sealed state, comprising a film lid and a container sealed by the lid, wherein the container includes a paper material layer. and a resin layer adhered to the paper material layer is laminated, and the container includes a container body formed in a concave shape and capable of containing contents, and a container body extending outward from the upper end of the container body. The flange portion is provided with a heat-sealed portion in which the flange portion and the lid portion are heat-sealed, and the heat-sealed portion extends along the entire circumference of the flange portion. The heat-sealed portion includes a steam discharge portion for discharging steam generated by heating the contents in a microwave oven, and the steam discharge portion is provided in the flange portion If a portion between the inner edge and the outer edge of the flange portion is a steam discharge flange portion, a warp generation structure is provided so that the steam discharge flange portion is warped during the heating. A package is provided.

The inventor of the present invention conducted extensive research into the cause of the tendency of the steam flow path to close in a package using a paper material container, and found the following. In the case of a resin container, since it softens when heated, the flange tends to warp when the package expands due to the internal pressure (in other words, the flange tends to deform so that the outer edge of the flange becomes higher). It has been found that such deformation tends to form a gap between the flange portion and the lid portion even during cooling, making it difficult to close the steam flow path. On the other hand, a container made of paper material hardly softens when heated, or rather hardens due to a decrease in water content, so that the flange portion is less likely to deform when the package expands due to the internal pressure. For this reason, it has been found that a gap is less likely to be formed between the flange portion and the lid portion, making it easier to close the steam flow path.

Then, based on such knowledge, by providing the package with a warp generating structure configured so that the steam discharge flange portion warps when heated, even in the package using the paper material container, The inventors have found that it is possible to warp the steam discharge flange portion, and that the inside of the package can be prevented from being decompressed after being heated in a microwave oven, thereby completing the present invention.

Various embodiments of the present invention are illustrated below. The embodiments shown below can be combined with each other.
Preferably, in the package described above, the steam exhaust portion is configured by curving a part of the heat-welded portion toward the inner edge of the flange portion, and the heat-welded portion is combined with the first heat-welded portion. Then, the warp generation structure is a packaging bag including a second heat-sealed portion in which the steam discharge flange portion and the lid portion are heat-sealed between the outer edge of the steam discharge portion and the outer edge of the steam discharge flange portion. be.
Preferably, in the package described above, the second heat-sealed portion is provided between the tip of the outer edge of the steam discharge portion and the outer edge of the steam discharge flange portion.
Preferably, the package as described above, wherein the second heat weld is configured to narrow the steam discharge path towards the outer edge of the steam discharge flange.
Preferably, in the package described above, the warp generating structure includes a folding line structure provided along the boundary between the steam discharge flange portion and the container body.
Preferably, in the package described above, in the warp-generating structure, the sloped portion that slopes downward along the outer edge of the flange portion extends at least one side of the outer edge of the steam discharge flange portion. The package body includes a structure provided in at least a part of a portion other than the steam discharge flange portion, but not provided in the steam discharge flange portion.
Preferably, in the package described above, in the warping structure, the angle between the steam discharge flange and the container body at the boundary between the steam discharge flange and the container body is 120 degrees or less. A package including a structure that is
Preferably, the package as described above, wherein the heat-sealed portion is flat.
Preferably, in the package described above, the lid portion is heat-shrinkable.
Preferably, it is the package described above, wherein an opening is provided in the lid portion or the steam exhaust flange portion between the outer edge of the steam exhaust portion and the outer edge of the steam exhaust flange portion.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view of the package 1 for microwave ovens of 1st Embodiment of this invention. The dashed-dotted line in the drawing represents a boundary line along which the curvature of the surface forming the surface shape changes. The same applies to other figures. 2A is a plan view of package 1 in FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB in FIG. 2A. 3 is an enlarged view of area A in FIG. 2; FIG. FIG. 4A is a perspective view of a portion near the steam discharge part 7, and FIG. 4B shows a state in which a region 7c near the steam discharge part 7 expands as the internal pressure of the package 1 rises. FIG. 4B is a diagram corresponding to FIG. 4A; FIG. 5A is a perspective view of the package 1 of FIG. 1 as viewed obliquely from below, and FIG. 5B is an enlarged view of region B in FIG. 5A. 6A is a CC cross-sectional view in FIG. 3, FIG. 6B shows the state immediately after the package 1 expands from the state of FIG. 6A and peeling occurs at the steam discharge part 7, and FIG. 6B is an enlarged view of area C in FIG. 6A; FIG. FIG. 3 is a perspective view for explaining a method of manufacturing the package 1; 8A is a perspective view of the seal bar 9 in FIG. 7, and FIG. 8B is an enlarged view of area B in FIG. 8A. It is an enlarged view corresponding to FIG. 3 about the packaging body 1 for microwave ovens of 2nd Embodiment of this invention.

Embodiments of the present invention will be described below. Various features shown in the embodiments shown below can be combined with each other. In addition, the invention is established independently for each characteristic item.

1. Basic Configuration of Microwave Package 1 As shown in FIGS. 1 to 6, a microwave package 1 according to a first embodiment of the present invention is used to store contents F in a sealed state. The packaging body 1 includes a film-like lid portion 2 and a container 3 sealed by the lid portion 2 . Contents F include foods that contain moisture and can be heated or cooked in a microwave oven, such as retort foods.

The container 3 is a container made of paper material, which is formed by laminating a paper material layer and a resin layer adhered thereto. The paper material layer can be composed of a paper material such as pulp. The resin layer can be made of any resin that can be heat-sealed with the lid 2. For example, the resin layer can be made of polyolefin resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, and ethylene-propylene block copolymer. Can be configured. The resin layer can be adhered to the paper stock layer with an adhesive.

The container 3 has a container main body 4 formed in a concave shape and capable of containing the contents F, and an annular flange portion 5 provided so as to extend outward from an upper end 4 a of the container main body 4 . The flange portion 5 is provided with a thermally welded portion 6 in which the flange portion 5 and the lid portion 2 are thermally welded. The thermally welded portion 6 is annular and provided along the entire circumference of the flange portion 5 . Therefore, the contents F are hermetically sealed in the package 1 by heat-sealing the flange portion 5 and the lid portion 2 at the heat-sealing portion 6 .

The heat-sealing part 6 includes a steam discharge part 7 for discharging steam generated by heating the contents F in the microwave oven. The steam discharge portion 7 is a portion that is easier to peel off than the other portion 6a of the heat-sealed portion 6, and when the internal pressure of the package 1 increases as the contents F are heated, the lid portion of the steam discharge portion 7 is opened. 2 and the flange portion 5 are separated preferentially, steam can be discharged through the steam discharge portion 7 . According to such a configuration, it is possible to prevent the steam from leaking from an unintended portion, or to prevent the package 1 from bursting without discharging the steam.

The steam discharge portion 7 is preferably configured by curving a portion of the heat-welded portion 6 toward the inner edge 5 a of the flange portion 5 . In this case, the steam discharge part 7 has a substantially V shape. According to such a shape, the peeling force generated as the internal pressure of the package 1 rises tends to be concentrated on the tip A of the steam discharging portion 7, so that the peeling at the steam discharging portion 7 becomes easier.

As shown in FIG. 3 , the vapor discharge portion 7 is located on the tip A side of a first line segment 7 e connecting a pair of roots 7 a on the inner edge side of the vapor discharge portion 7 . It is preferable that the average line width of the steam discharge portion 7 is smaller than the average line width of the other portion 6 a of the thermally welded portion 6 . The average line width of the steam exhaust portion 7 is calculated by dividing the area of the portion on the tip A side of the line segment 7e by the length of the steam exhaust portion 7 in the longitudinal direction. The average line width of the other portion 6a is calculated by dividing the area of the portion on the side farther from the tip A than the root 7a by the length of the other portion 6a in the longitudinal direction. The length in the longitudinal direction is, in other words, the length of the central line in the line width direction. The value of {average line width of steam discharge portion 7/average line width of other portion 6a} is, for example, 0.01 to 0.9 (0.20 in this embodiment), and 0.05 to 0.05. 5 is preferred, and 0.1 to 0.4 is more preferred. Specifically, this value is, for example, 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, and may be in the range between or less than any two of the values exemplified herein.

As shown in FIG. 3, the length of the first line segment 7e connecting the pair of roots 7a is L1, and the point where the straight line passing through the tip A and parallel to the first line segment 7e reaches the inner edge of the thermally welded portion 6. is B and the length of the second line segment 7f connecting the tip A and the point B is L2, then L2/L1≧1.0 (1.3 in this embodiment). As the value of L2/L1≧1.0 increases, as shown in FIGS. 4A and 4B, the region 7c adjacent to the steam discharge portion 7 tends to swell due to the internal pressure caused by the steam from the contents F. As a result, The peeling force generated as the internal pressure of the package 1 rises tends to be concentrated on the tip A of the steam discharge portion 7, and the peeling at the steam discharge portion 7 becomes easier. L2/L1 is, for example, 1.0 to 3.0, preferably 1.1 to 1.8, more preferably 1.2 to 1.6. Specifically, this value is, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, 3.0, and may be in the range between or above any two of the values exemplified herein.

As shown in FIG. 3, the angle formed by the line segment S1 connecting the tip A and the root 7a and the line segment S2 connecting the root 7a and the point B is preferably 91 to 120 degrees (102 degrees in this embodiment). In this case, the peeling force generated as the internal pressure of the package 1 rises tends to be concentrated on the tip A of the steam discharge portion 7, and the peeling at the steam discharge portion 7 becomes easier. Specifically, this angle is, for example, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120 degrees, and may be in the range between any two of the values exemplified herein.

The angle between a pair of line segments S1 connecting the tip A and the root 7a (90 degrees in this embodiment) is preferably 60 to 120 degrees, more preferably 80 to 110 degrees. Specifically, the angles are, for example, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, and 120 degrees. may be within the range of

It is preferable that the vapor discharge portion 7 is curved such that a portion 7b between the tip A and the base 7a is convex toward the outer edge 7d of the vapor discharge portion 7. As shown in FIG. In this case, in the vicinity of the tip A, the gap between the pair of parts 7b is narrowed and the gap between the pair of roots 7a is widened. The steam exhaust path after peeling is widened.

The tip A of the steam discharge part 7 is preferably sharp. In this case, peeling at the tip A becomes easier.

Preferably, the heat welded portion 6 has a transition portion 8 at a position adjacent to the vapor discharge portion 7 , the line width of which gradually narrows toward the vapor discharge portion 7 . The transition portion 8 is preferably formed by the inner edge of the transition portion 8 approaching the outer edge of the flange portion 5 . In this case, since the region 7c adjacent to the vapor discharge portion 7 becomes wider, the peeling at the vapor discharge portion 7 becomes easier. Note that the transition portion 8 is part of the other portion 6a.

The maximum value of the angle between the outer edge and the inner edge of the transition portion 8 is, for example, 5 to 30 degrees (12 degrees in this embodiment), preferably 8 to 15 degrees. Specifically, this maximum value is, for example, , 25, 26, 27, 28, 29, 30 degrees, and may be in the range between any two of the values exemplified herein.

It is preferable that the thermally welded portion 6 is provided on the flat surface of the flange portion 5 . The container 3 is made of a material containing a paper material such as pulp, but such a material is less moldable than resin, and it is difficult to form ribs on the flange portion 5 with high precision. Sometimes. Therefore, by providing the thermally welded portion 6 on the flat surface of the flange portion 5, the thermally welded portion 6 can be accurately formed regardless of the material forming the container 3. FIG.

It is preferable that the flange portion 5 is provided with a wide portion 5b. The wide portion 5b is a portion whose width (the distance between the inner edge and the outer edge of the flange portion 5) is wider than the average value of the flange portion 5 as a whole. The steam discharge portion 7 is preferably provided in the wide portion 5b. It is possible to provide the steam discharge part 7 without widening the width of the entire flange part 5 to match the steam discharge part 7 or protruding the inner edge 5a of the flange part 5 toward the inside of the container 3. . Further, the outer edge 5c of the flange portion 5 preferably has a rectangular shape in which the corners may be chamfered in plan view, and the wide portion 5b is preferably provided at the corners of the rectangle. In addition, planar view means that the package 1 for microwave ovens is seen from above in the vertical direction.

The lid portion 2 is preferably made of a film having an outer edge approximately the same size as the outer edge of the flange portion 5 . The lid 2 preferably comprises a base layer and a sealant layer. The lid portion 2 preferably has heat shrinkability. In one example, the lid portion 2 can be heat-shrinkable by configuring the base layer with a shrink film (heat-shrinkable film). After the steam is discharged from the steam discharge part 7, when the lid part 2 and the flange part 5 are in close contact with each other at the steam discharge part 7, the inside of the package 1 is decompressed when the package 1 cools down. However, if the lid portion 2 is heat-shrinkable, the shrinkage of the lid portion 2 makes it difficult for the lid portion 2 and the flange portion 5 to come into close contact with each other. It is possible to prevent the lid portion 2 and the flange portion 5 from coming into close contact with each other by warping the flange portion 5 due to the shrinkage force of .

A shrink film is a resin film that is heat-shrinkable by, for example, stretching (uniaxial stretching or biaxial stretching). A resin, such as an olefin resin such as polyethylene or polypropylene, can be used. In addition, the cover part 2 may laminate|stack outer layers, such as a printing layer, on the outer side of a base material layer.

The sealant layer can be formed of, for example, polyolefin resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-propylene block copolymer, and more specifically non-stretched polypropylene or linear Low density polyethylene can be used. More preferably, an easy-peel sealant obtained by mixing polyethylene and polypropylene in a predetermined ratio may be used. By doing so, it becomes easy to peel off the lid portion 2 from the flange portion 5 .

Here, it is also possible to adjust the peel strength by changing the ratio of the mixed resins. For example, when the container body 4 is made of polypropylene, the adhesive strength can be increased by increasing the proportion of polypropylene contained in the mixed resin, and conversely, the peelability can be increased by decreasing the proportion of polypropylene contained in the mixed resin.

2. Warpage generation structure If the portion between the inner edge 5a and the outer edge 5c of the flange portion 5 in the portion where the steam discharge portion 7 is provided in the flange portion 5 is the steam discharge flange portion 5d, the package 1 of this embodiment has A warp generation structure is provided so that the steam discharge flange portion 5d is warped during heating (that is, the flange portion is deformed so that the outer edge 5d1 side of the steam discharge flange portion 5d becomes higher). ing. Examples of the warping structure include the structures shown below, and at least one of these structures is included in the package 1 . If the lid portion 2 has heat shrinkability, the steam discharge flange portion 5d is particularly likely to warp. Therefore, it is not essential for the lid portion 2 to have heat-shrinkability.

Regarding the magnitude of the warp, the value of {height of the outer edge 5d1 - height of the inner edge 5d2 of the steam discharge flange 5d} at the point/location where the warp becomes the largest during heating is 0.5 mm or more. is preferably 1 mm or 2 mm or more. This value is, for example, 0.5 to 5 mm. 0, 4.5, 5.0 mm, and may be in the range between any two of the values exemplified herein, or any or more. Further, it is more preferable that the warp value at the portion where the warp is greatest immediately after the steam escapes from the package 1 or after the package 1 is cooled is the above value.

(1) Second Thermal Welding Part 11
Assuming that the thermally welded portion 6 is the first thermally welded portion, the warpage generating structure is such that the steam discharge flange portion 5d and the lid portion 2 are thermally welded between the outer edge 7d of the steam discharge portion 7 and the outer edge 5d1 of the steam discharge flange portion 5d. It is preferable to include the second thermally welded portion 11 . If the second heat-sealed portion 11 is provided at such a position, the package 1 expands as shown in FIG. 2 pulls the position near the outer edge 5d1 of the steam discharge flange portion 5d, the steam discharge flange portion 5d is likely to be warped.

The second heat-welded portion 11 is preferably provided between the tip A1 of the outer edge 7d of the steam discharge portion 7 and the outer edge 5d1 of the steam discharge flange portion 5d. In this case, the second thermally welded portion 11 serves as a point seal portion away from the steam discharge portion 7 . Moreover, it is preferable to provide the second heat-welded portion 11 so that the line connecting the center of the second heat-welded portion 11 and the tip A becomes the axis of symmetry of the vapor discharge portion 7 .

Further, the second heat-welded portion 11 may be configured to narrow the steam discharge path toward the outer edge 5d1 of the steam discharge flange portion 5d, as in the second embodiment shown in FIG. In this case, the second thermally welded portion 11 is composed of a pair of portions 11a. The portions 11a are preferably connected to the base 7a of the steam discharge portion 7 respectively. In such a configuration, steam is accumulated between the pair of portions 11a, and the steam discharge flange portion 5d is more likely to warp.

(2) polygonal line structure 12
The warping structure preferably includes a fold line structure 12 provided along the boundary between the steam discharge flange portion 5d and the container body 4, as shown in FIGS. The bent line structure 12 is a linear structure for facilitating the bending deformation of the steam discharge flange portion 5d with respect to the container body 4, and in one example, is composed of a groove 12a. By providing the folding line structure 12, bending deformation of the steam discharge flange portion 5d with respect to the container body 4 is facilitated, so that the steam discharge flange portion 5d is likely to be warped. Warp is likely to occur in the steam discharge flange portion 5d.

(3) Notch 5e1 in inclined portion 5e
In order to increase the rigidity of the flange portion 5, the paper material container is generally provided with an inclined portion 5e that is inclined downward from the flange portion 5 along the outer edge 5c of the flange portion 5. As shown in FIG. The inclined portion 5 e contributes to strengthening the rigidity of the flange portion 5 , but on the other hand, it suppresses warping of the flange portion 5 .

In the present embodiment, as shown in FIG. 5, the warp generation structure is such that the inclined portion 5e is at least part of the outer edge 5d1 of the steam discharge flange portion 5d (preferably 50%, 60%, 70, 80%, 70%, 80%, 70%, 80%, 70%, 80%, and 80%) of the outer edge 5d1 of the steam discharge flange portion 5d. 90% or more or 100%), and at least a portion of the portion other than the steam discharge flange portion 5d (preferably 50%, 60%, 70, 80% of the outer edge 5c of the portion other than the steam discharge flange portion 5d) , more than 90% or 100%) preferably include structures provided. That is, a structure in which a local notch 5e1 is provided in the inclined portion 5e at the outer edge 5d1 of the steam discharge flange portion 5d is preferable. In this case, since warping of the steam discharge flange portion 5d is less likely to be suppressed by the inclined portion 5e, the steam discharge flange portion 5d is more likely to warp.

(4) Angle between flange portion 5 and container body 4 As shown in FIG. Includes structures where the angle α between them is less than or equal to 120 degrees (108 degrees in this embodiment). The smaller the angle α, the easier it is for the steam discharge flange portion 5d to warp. The angle α is preferably 115 degrees or less, more preferably 110 degrees or less. This angle is, for example, 90 to 120 degrees, specifically, for example, 90, 95, 100, 105, 110, 115, 120 degrees, within a range between any two of the numerical values exemplified here, or may be less than or equal to

3. opening 13
An opening 13 is preferably provided in the lid portion 2 or the steam discharge flange portion 5d between the outer edge 7d of the steam discharge portion 7 and the outer edge 5d1 of the steam discharge flange portion 5d. It is preferable that the opening 13 is configured by a notch or a notch. Since the lid portion 2 and the steam discharge flange portion 5d are particularly likely to come into close contact at the outer edge 5d1 of the steam discharge flange portion 5d, outside air is introduced into the package 1 by providing the opening 13 between the outer edge 5d1 and the outer edge 7d. easier to be Although the opening 13 is provided in the lid portion 2 in this embodiment, the opening 13 may be provided in the steam discharge flange portion 5d. Moreover, when the second heat-welding portion 11 is provided, the opening 13 is preferably provided in a region between the outer edge 7d of the steam discharge portion 7 and the inner edge of the second heat-welding portion 11, for example.

4. Method for manufacturing microwave package 1 As shown in FIG. 7, microwave package 1 is prepared by disposing lid 2 on flange 5 while container 3 is filled with contents F. can be manufactured by pressing the seal bar 9 against the lid portion 2 to form the heat-sealed portion 6 .

As shown in FIG. 8, the seal bar 9 is provided with protruding portions 9a and 9b having shapes corresponding to the shapes of the thermally welded portions 6 and 11, and the heated protruding portion 9a is attached to the lid portion 2. By pressing, the lid portion 2 and the flange portion 5 can be thermally welded.

Further, by providing the cutter 14 on the seal bar 9 and placing it, the opening 13 can be formed by pressing the cutter 14 against the lid portion 2 when forming the thermally welded portion 6 .

1: Package for microwave oven 2: Lid 3: Container 4: Container main body 4a: Upper end 5: Flange 5a: Inner edge 5b: Wide portion 5c: Outer edge 5d: Steam discharge flange 5d1: Outer edge 5d2: Inner edge 5e: Inclined Part 5e1 : Notch 6 : Thermally welded part 6a : Part 7 : Steam discharge part 7a : Root 7b : Part 7c : Area 7d : Outer edge 7e : First line segment 7f : Second line segment 8 : Transition part 9 : Seal bar 9a: Protruding portion 9b: Protruding portion 11: Second heat-sealed portion 11a: Site 12: Folded line structure 12a: Grooved line 13: Opening portion 14: Cutter A: Tip A1: Tip F: Contents

Claims (10)

A package for a microwave oven for storing contents in a sealed state,
A film-like lid and a container sealed by the lid,
The container is configured by laminating a paper material layer and a resin layer adhered to the paper material layer,
The container has a container body formed in a concave shape and capable of containing contents, and an annular flange portion provided to extend outward from the upper end of the container body,
The flange portion is provided with a heat-sealed portion in which the flange portion and the lid portion are heat-sealed,
The heat-sealed portion is provided over the entire circumference of the flange portion,
The heat-sealing part includes a steam discharge part for discharging steam generated by heating the contents in a microwave oven,
If the part between the inner edge and the outer edge of the flange part where the steam discharge part is provided in the flange part is defined as the steam discharge flange part,
A package, further comprising a warp generating structure configured to warp the steam discharge flange portion during the heating. The package according to claim 1,
The steam discharge portion is configured by curving a part of the thermally welded portion toward the inner edge of the flange portion,
Assuming that the thermally welded portion is the first thermally welded portion,
The warpage generating structure includes a second heat-sealed portion in which the steam discharge flange portion and the lid portion are heat-sealed between the outer edge of the steam discharge portion and the outer edge of the steam discharge flange portion. A package according to claim 2,
The package body, wherein the second heat-sealed portion is provided between the tip of the outer edge of the steam discharge portion and the outer edge of the steam discharge flange portion. A package according to claim 2,
The package, wherein the second heat weld is configured to narrow the steam discharge path toward the outer edge of the steam discharge flange. The package according to any one of claims 1 to 4,
The package, wherein the warping structure includes a fold line structure provided along a boundary between the steam discharge flange portion and the container body. The package according to any one of claims 1 to 5,
In the warpage generating structure, a sloped portion that slopes downward along the outer edge of the flange portion is not provided in at least a part of the outer edge of the steam discharge flange portion, and the steam discharge flange portion is A package including a structure provided in at least a part of a part other than the part. The package according to any one of claims 1 to 6,
The package, wherein the warping structure includes a structure in which an angle between the steam discharge flange and the container body at a boundary between the steam discharge flange and the container body is 120 degrees or less. The package according to any one of claims 1 to 7,
The package, wherein the heat-sealed portion is flat. The package according to any one of claims 1 to 8,
The package body, wherein the lid portion is heat-shrinkable. The package according to any one of claims 1 to 9,
A package, wherein an opening is provided in the lid or the steam exhaust flange between the outer edge of the steam exhaust and the outer edge of the steam exhaust flange.

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