JP2024079534A - How to prepare packaged foods - Google Patents

Abstract

A method for cooking packaged food is provided that can increase the uniformity of heating of the contents when the contents, such as food, are stored and cooked in a microwave oven.
[Solution] According to the present invention, there is provided a cooking method for packaged food, which includes a heating step, wherein the packaged food comprises a packaging bag and food contained in the packaging bag, the packaging bag having a bottom portion and a peripheral portion arranged to rise from the bottom portion, and wherein, in the heating step, heating of the food contained in the packaging bag is started in a microwave oven with the peripheral portion inclined at an angle of 30° or less with respect to the horizontal plane, and when heating is completed, the peripheral portion is in an upright position.
[Selected Figure] Figure 1

Description

The present invention relates to a method for cooking packaged foods.

As a packaging bag for containing food or other contents, a packaging bag that can be heated in a microwave oven is known. For example, the packaging bag disclosed in Patent Document 1 can be heated in a microwave oven in a self-supporting state, and can release steam from a steam release means when heated.

JP 2005-306426 A

When cooking food in a microwave oven, it is desirable for the entire contents to be heated evenly. However, there are areas inside the microwave oven that are easily hit by microwaves and areas that are not, so it is not easy to heat the contents evenly.

The present invention was made in consideration of these circumstances, and provides a method for cooking packaged food that can increase the uniformity of heating of the contents when the contents, such as food, are stored and cooked in a microwave oven.

According to the present invention, the following inventions are provided.
[1] A cooking method for a packaged food, comprising a heating step, the packaged food comprising a packaging bag and food contained in the packaging bag, the packaging bag having a bottom surface and a peripheral surface extending upward from the bottom surface, and in the heating step, heating of the food contained in the packaging bag is commenced in a microwave oven with the peripheral surface inclined at an angle of 30° or less with respect to the horizontal plane, and when heating is completed, the peripheral surface is in an upright position.
[2] The method according to [1], further comprising a containing step, in which a cooking liquid is contained in the packaging bag so as to come into contact with the food and the packaging bag is sealed, and in which the heating step heats the food and the cooking liquid contained in the packaging bag in a microwave oven.
[3] The method according to [1] or [2], wherein the bottom portion is expandable, and the heating step is initiated in a state where the bottom portion is expanded and in contact with the ground.
[4] A method according to any one of [1] to [3], wherein the bottom portion is constituted by a bottom film, and the heating process is initiated in a state in which a reinforcing member is provided on the bottom portion to reinforce the bottom portion so as to suppress curvature of the bottom film.

In the present invention, heating is started with the peripheral surface lying down (i.e., tilted at an angle of 30° or less with respect to the horizontal plane), and the heating process is performed so that the peripheral surface is in an upright state when heating is completed. In this process, the peripheral surface changes from a lying down state to an upright state during heating. This change also causes the contents to change, stirring the contents and changing the distribution of microwaves irradiated to the contents, thereby improving the uniformity of heating.

Fig. 1 is a perspective view of a packaging bag 1 according to a first embodiment of the present invention with contents stored therein. For convenience of illustration, the steam release seal portion 11 is omitted as appropriate. The same applies to Figs. 2 and onwards. Fig. 2A is a perspective view showing a state in which the packaging bag 1 in Fig. 1 is opened at an upper opening portion 26. Fig. 2B is a perspective view showing a state in which the packaging bag 1 in Fig. 2A is opened at an opening portion 24 after being expanded by heating. Fig. 3A is a plan view of the packaging bag 1 in Fig. 1 in a flattened state. Fig. 3B is a rear view of the packaging bag 1 in Fig. 1 in a flattened state. 2 is a perspective view of a bottom film 20a that constitutes the bottom portion 2 of the packaging bag 1. FIG. Figures 5A to 5C are explanatory diagrams of the manner in which the opening 22 of the packaging bag 1 is opened and closed by the opening/closing member 23. Figure 5A is a cross-sectional view taken along line A-A in Figure 3A. Figure 5B is an enlarged view of region B in Figure 5A. Figure 5C shows the state in which the opening/closing member 23 in Figure 5B is open. 2B is a perspective view of the packaging bag 1 of FIG. 2A, in which the front portion 3 and the back portion 4 are integrally tilted rearward, as viewed from the back portion 4 side. Fig. 7A is a plan view of the packaging bag 1 in Fig. 1 in a flattened state, and Fig. 7B is a perspective view of the packaging bag 1 with contents contained therein. Figures 8A to 8C are explanatory diagrams of a method for cooking a packaged food in which food is contained in a packaging bag 1, and are schematic cross-sectional views taken along line D-D in Figure 6. Figure 8A shows the state of the packaging bag 1 at the start of heating in the heating step of the cooking method. Figure 8B shows the state of the packaging bag 1 after it has expanded due to heating, as shown in Figure 8A. Figure 8C shows the state of the packaging bag 1 after it has expanded further due to heating, as shown in Figure 8B. Fig. 9A is a side view of the peripheral wall film 20b, and Fig. 9B is a diagram showing a state in which a part of the peripheral wall film 20b has been cut and the bottom film 20a has been inserted into the cut portion. FIG. 10A is a diagram showing how the peripheral wall film 20b and the bottom film 20a are welded together to produce the packaging bag 1, and FIG. 10B is a diagram showing the state in which the opening/closing member 23 has been inserted between the front portion 3 and the back portion 4. Figures 11A to 11C are explanatory diagrams of a cooking method for a packaged food in which food is accommodated in a packaging bag 1 according to the second embodiment, and are schematic cross-sectional views taken along line D-D in Figure 6. Figure 11A shows the state of the packaging bag 1 at the start of heating in the heating step of the cooking method. Figure 11B shows the state of the packaging bag 1 after it has expanded due to heating, as shown in Figure 11A. Figure 11C shows the state of the packaging bag 1 after it has expanded further due to heating, as shown in Figure 11B. 10 is a perspective view of a packaging bag 1 according to a second embodiment of the present invention, showing the state after it has been opened at an opening portion 24 after it has expanded due to heat. FIG. Figure 13 is a bottom view showing the state in which a reinforcing member 27 is attached to the bottom portion 2, where Figure 13A shows the state in which an elliptical reinforcing member 27 is attached, Figure 13B shows the state in which a pair of reinforcing members 27 are attached near both ends in the left-right direction of the packaging bag 1, Figure 13C shows the state in which a reinforcing member 27 is attached to the center in the left-right direction of the packaging bag 1, and Figure 13D shows the state in which a reinforcing member 27 is attached to the center in the front-to-back direction of the packaging bag 1. This is a bottom view of the state in which a reinforcing member 27 shaped to fit the inner edge 2j of the lower end welded portion 13 is attached. 15A is an oblique view showing the state in which disposable chopsticks 27a are attached to the bottom portion 2 as reinforcing members 27, FIG. 15B is an enlarged view of region B in FIG. 15A, and FIG. 15C shows the state in which disposable chopsticks 27a have been removed from FIG. 15B. Figure 16A is an oblique view showing the state in which a disposable chopstick 27a is inserted into an opening 2f provided in the lower end welded portion 13 of the bottom portion 2 as a reinforcing member 27 and attached to the bottom portion 2, Figure 16B is an enlarged view of area B in Figure 16A, and Figure 16C shows the state from Figure 16B with the disposable chopstick 27a removed. 13 is a perspective view showing an example of a method for fixing a reinforcing member 27 to a bottom portion 2 using a fixing means 29. FIG. Fig. 18A is a perspective view showing a state in which bottom film 20a and reinforcing member film 20d are joined, and corresponds to Fig. 4. Fig. 18B is a perspective view of packaging bag 1 manufactured using the film of Fig. 18A. 8B is a cross-sectional view corresponding to FIG. 8A, showing a state in which a reinforcing member 27 protrudes from a bottom surface portion 2. FIG. 8B is a perspective view corresponding to FIG. 8A, showing a state in which the packaging bag 1 is attached to a plate 30a with double-sided tape 29a. FIG. 21A shows a process of fixing the lower end 20j of the peripheral wall film 20b to a plate-like member 42, and FIG. 21B shows a process of fixing the bottom film 20a to the back surface of the plate-like member 42 of FIG. 21A. Figure 22A shows the state in which the steam release seal portion 11 is provided at the upper end welded portion 19, Figure 22B shows the state in which the steam release seal portion 11 is provided at the side end welded portion 12, and Figure 22C is a plan view corresponding to Figure 3A, showing the state in which the steam release seal portion 11 is provided so as to protrude from the inner edge 12a of the side end welded portion 12. 1 is a plan view showing a state in which a doughnut-shaped steam release seal portion 11a is provided. FIG. Fig. 24A is a perspective view showing a state in which an overlapping portion 28 is formed on the film 20c. Fig. 24B is a perspective view showing a state after a first bottom surface portion 2a is formed on the overlapping portion 28 from the state of Fig. 24A. 24C is a perspective view showing the state after the second bottom surface portion 2b and the side end welded portion 12 have been formed from the state shown in FIG. 24B. 26A shows a state in which the packaging bag 1 is contained in a cylindrical outer wrapping body 32a, and FIG. 26B shows a state in which the outer wrapping body 32a has been folded back in a band shape from the state shown in FIG. 26A. 27A shows a state in which the packaging bag 1 is contained in a box-shaped outer wrapping body 32b, and FIG. 27B shows a state in which the outer wrapping body 32b has been opened from the state shown in FIG. 27A.

The following describes an embodiment of the present invention with reference to the drawings. The features of the following embodiment can be combined with each other. Each feature can also be used as an invention independently.

The following embodiments disclose the first to seventh aspects of the invention, and the claims relate to at least a portion of them.

(First viewpoint)
In this aspect, there is provided a packaging bag for a microwave oven in which a flexible film is formed into a bag shape, the packaging bag having a bottom portion and a peripheral portion, the bottom portion being constituted by a bottom film, the peripheral portion having a front portion and a back portion which face each other and are arranged to rise from the bottom portion, the front portion and the back portion being configured so as to be integrally inclined toward the front or rear side of the packaging bag relative to the bottom portion, and the bottom portion being provided with a reinforcing member which reinforces the bottom portion so as to suppress bending of the bottom film.

(Second viewpoint)
In this aspect, there is provided a cooking method for packaged food, comprising a heating step, wherein the packaged food comprises a packaging bag and food contained in the packaging bag, the packaging bag having a bottom portion and a peripheral portion arranged to rise from the bottom portion, and wherein, in the heating step, heating of the food contained in the packaging bag is started in a microwave oven with the bottom portion grounded and the peripheral portion inclined at an angle of 30° or less with respect to the horizontal plane, and when heating is completed, the peripheral portion is in an upright state.

(Third Viewpoint)
In this aspect, there is provided a packaging bag for a microwave oven in which a flexible film is formed into a bag shape, the packaging bag having a bottom portion and a peripheral portion, the peripheral portions facing each other and having front and rear portions arranged to rise from the bottom portion, the front and rear portions being configured so as to be integrally tiltable toward the front or rear side of the packaging bag relative to the bottom portion, and the bottom portion being unfoldable.

(Fourth viewpoint)
In this aspect, there is provided a cooking method for a packaged food, comprising a heating step, the packaged food comprising the packaging bag described in the third aspect and food contained in the packaging bag, and in the heating step, heating of the food contained in the packaging bag is commenced in a microwave oven with the bottom portion unfolded and grounded and the peripheral portion inclined so that the inclination angle with respect to the horizontal plane is 30° or less.

(Fifth viewpoint)
In this aspect, there is provided a packaging bag for a microwave oven in which a flexible film is formed into a bag shape, the packaging bag having a bottom portion and a peripheral portion, the peripheral portion having a front portion and a back portion opposed to each other and rising from the bottom portion, the front portion and the back portion being configured to be integrally tiltable, the front portion being provided with a steam release seal portion which forms a steam flow path as the internal pressure of the packaging bag increases, the bottom portion being unfoldable, and the peripheral portion being inclined such that when the bottom portion is unfolded, the bottom portion and the back portion form a valley fold, and the inclination angle relative to the bottom portion is 30° or less.

(Sixth viewpoint)
In this aspect, there is provided a cooking method for packaged food, comprising a heating step, wherein the packaged food comprises a packaging bag and food contained in the packaging bag, the packaging bag having a bottom portion and a peripheral portion arranged to rise from the bottom portion, and wherein, in the heating step, heating of the food contained in the packaging bag is started in a microwave oven with the peripheral portion inclined at an angle of 30° or less with respect to the horizontal plane, and when heating is completed, the peripheral portion is in an upright state.

(Seventh Viewpoint)
In this aspect, there is provided a method for manufacturing a packaging bag with a reinforcing member for use in a microwave oven, the method comprising: a reinforcing member attachment step, in which a reinforcing member is attached to the bottom portion of the packaging bag in an unfolded state; the packaging bag is formed by forming a flexible film into a bag shape; the packaging bag has a bottom portion and a peripheral portion, the bottom portion is formed by a bottom film, the peripheral portion has front and back portions opposed to each other and arranged to rise from the bottom portion, the front portion and the back portion are configured to be integrally inclined toward the front or rear side of the packaging bag relative to the bottom portion; and the reinforcing member is configured to be capable of reinforcing the bottom portion so as to suppress curvature of the bottom film.

1. First embodiment 1.1. Configuration of packaging bag 1 As shown in Fig. 1, the packaging bag 1 of the first embodiment of the present invention is a packaging bag for use in a microwave oven, in which a flexible film is formed into a bag shape. The packaging bag 1 has an enclosed space S therein, and contents are contained in the enclosed space S. The packaging bag 1 is preferably used when the contents are food to be cooked in a microwave oven, and is particularly preferably used when the contents are instant noodles.

As shown in Figs. 1 to 3B, the packaging bag 1 has a bottom portion 2 and a peripheral portion 21. The bottom portion 2 is made of a bottom film 20a shown in Fig. 4, and is provided with a reinforcing member 27 as shown in Fig. 1. The peripheral portion 21 is provided so as to rise from the bottom portion 2, and has a front portion 3 and a back portion 4 that face each other in the front-to-rear direction.

The front portion 3 and the back portion 4 are welded (heat sealed) to each other at their left and right ends (hereinafter also referred to as side ends). The bottom film 20a of the bottom portion 2 is welded to the front portion 3 and the back portion 4. The bottom portion 2, the front portion 3, and the back portion 4 are welded to each other, so that the film is bag-shaped. The front portion 3 and the back portion 4 are welded above the folds 31 and 41 shown in Figures 1 and 6, and the bottom portion 2 and the front portion 3 are welded and the bottom portion 2 and the back portion 4 are welded below the folds 31 and 41. Below the folds 31 and 41, the front portion 3 and the back portion 4 are not welded, and the bottom portions 2 are not welded to each other. Therefore, the bottom portion 2 is unfoldable, and the bottom portion 2 can be spread out to a flat state.

3A and 3B are diagrams showing the packaging bag 1 of FIG. 1 in plan view and back view, respectively. Plan view means that the packaging bag 1 is flattened without any contents and viewed in a direction perpendicular to the front portion 3. Back view means that the packaging bag 1 in the same state is viewed in a direction perpendicular to the back portion 4. In this disclosure, the top, bottom, left, and right of FIG. 3A are described as the top, bottom, left, and right of the packaging bag 1. Specifically, the bottom side is the bottom side, and the direction in which the front portion 3 (and the back portion 4) rises from the bottom portion 2 is the top side. The left and right sides when the front portion 3 is placed in front are the left and right sides of the packaging bag 1. Furthermore, the front portion 3 side is the front side, and the back portion 4 side is the back side. In the following description, the top and bottom direction may be referred to as the height direction. As shown in FIGS. 3A and 3B, the packaging bag 1 is formed to be linearly symmetrical with respect to a center line in the left-right direction.

As shown in Figures 1 to 2B, the packaging bag 1 can stand on its own with the bottom part 2 facing down. In this configuration, compared to a flat bag-shaped packaging bag in which the front part 3 and the back part 4 are welded at the bottom without the bottom part 2, a larger volume can be secured inside the packaging bag 1, and when the contents are food, the packaging bag 1 can stand on its own after heating and be used as tableware.

The front surface 3 has a lower front surface 3a and an upper front surface 3b. The lower front surface 3a is welded to the bottom film 20a of the bottom surface 2. The lower front surface 3a and the upper front surface 3b are welded at a seam 10 formed by overlapping the inner surfaces of these surfaces. By providing the seam 10, a large volume can be secured inside the packaging bag 1.

The peripheral surface 21 of the packaging bag 1 is provided with an upper opening portion 26, an opening/closing member 23, and an opening portion 24. The upper end of the packaging bag 1 is sealed by providing an upper end welding portion 19 that welds the front surface 3 and the back surface 4 along the left-right direction. The upper opening portion 26 is a portion for opening the upper end of the packaging bag 1, and an opening 22 that opens upward is formed as shown in FIG. 2A by tearing the peripheral surface 21 along the left-right direction at the upper opening portion 26 and cutting off the upper end side portion of the peripheral surface 21 including the upper end welding portion 19. This configuration is preferable from a hygienic point of view because the inner surface of the packaging bag 1 is not exposed to the outside before opening.

The upper opening section 26 has a tear initiation section 26a which is the starting point for tearing the peripheral section 21, and a cut line 26b on which a line indicating the portion to be cut out for opening is printed. The packaging bag 1 may be opened by tearing the peripheral section 21 starting from the tear initiation section 26a, or by cutting the peripheral section 21 along the cut line 26b using a cutting tool such as scissors. The tear initiation section 26a is formed, for example, by a notch or cut. Also, instead of the cut line 26b, a half-cut line extending in the circumferential direction of the peripheral section 21 may be provided, or a strip-shaped film may be arranged by welding so as to extend in the circumferential direction of the peripheral section 21, and the peripheral section 21 may be configured to be tearable along the strip-shaped film by pulling the strip-shaped film from the end.

The packaging bag 1 may be configured without the upper end welded portion 19 and the upper opening portion 26. In this case, the front portion 3 and the back portion 4 are not welded to each other at the upper end of the packaging bag 1, and an opening 22 is formed, so there is no need to open the upper end of the packaging bag 1.

The opening/closing member 23 is configured to be able to open and close the opening 22 in the packaging bag 1 when the upper end of the upper opening portion 26 is opened. Figures 5A to 5C are explanatory diagrams of the manner in which the opening 22 of the packaging bag 1 is opened and closed by the opening/closing member 23, and the upper ends of the front portion 3 and the back portion 4 in the figures coincide with the formation location of the cut line 26b. Position J shown in Figure 5B indicates the position of the lower end of the upper opening portion 26 in the vertical direction (in this embodiment, position J of the lower end of the tear start portion 26a shown in Figure 3A). The opening/closing member 23 includes a front side engaging member 23a and a back side engaging member 23b that can engage with each other. The base 23a1 of the front side engaging member 23a and the base 23b1 of the back side engaging member 23b are fixed by welding to the inner surfaces of the front portion 3 and the back portion 4, respectively. As shown in FIG. 5B, the hook portion 23a2 of the front side engaging member 23a and the hook portion 23b2 of the rear side engaging member 23b are engaged to close the opening 22, and as shown in FIG. 5C, the engagement is released to open the opening 22.

The entire surfaces of the bases 23a1 and 23b1 may be welded to the front portion 3 and the rear portion 4, respectively, but it is preferable that the surfaces located above and below the hook portions 23a2 and 23b2 are welded to the inner surface of the rear portion 4. Furthermore, it is more preferable that the base 23b1 of the rear side engaging member 23b is welded to the inner surface of the rear portion 4 at the surfaces located above and below the hook portions 23b2, and that the front side engaging member 23a welded to the front portion 3 where the joint portion 10 is provided is welded to the inner surface of the front portion 3 at the surface above the hook portions 23a2, and that the surface below the hook portions 23a2 is not welded to the front portion 3. In other words, it is more preferable to provide an unwelded portion with the front portion 3 so as to extend from the lower end of the base 23a1 to the upper end of the hook portions 23a2. In this case, when the internal pressure of the heated packaging bag 1 rises and the bag expands, force in the direction of opening the opening/closing member 23 is less likely to be applied to the opening/closing member 23, suppressing leakage of contents and steam from the opening/closing member 23.

As shown in FIG. 5B, the vertical distance H5 between the upper end of the upper one of the hook portions 23a2, 23b2 (in this embodiment, the upper end of the hook portion 23b2 of the rear side engagement member 23b) and the periphery of the opening 22 (in other words, the cut line 26b of the upper opening portion 26) is, for example, 3 mm to 20 mm, and preferably 5 mm or more, and can be, for example, 10 mm. The vertical distance H6 between the upper end of the opening/closing member 23 (in other words, the upper end of the base portion 23a1, 23b1) and the lower end of the upper opening portion 26 (in this embodiment, the lower end of the tear start portion 26a) is, for example, 0.5 mm to 7 mm, and preferably 1 mm or more, and can be, for example, 2 mm. By setting the distances H5 and H6 as described above, a sufficiently large gripping margin for placing fingers on the upper end of the packaging bag 1 when opening the opening 22 with the opening/closing member 23 can be secured.

The opening portion 24 is a portion for opening the packaging bag 1, and in this embodiment, the opening portion 24 includes a tear initiation portion 24a which is a starting point for tearing the peripheral portion 21, and a cut line 24b on which a line indicating the portion to be cut out for opening is printed. The packaging bag 1 may be opened by tearing the peripheral portion 21 starting from the tear initiation portion 24a, or by cutting the peripheral portion 21 along the cut line 24b using a cutting tool such as scissors. The tear initiation portion 24a is formed, for example, by a notch or a cut. Also, instead of the cut line 24b, a half-cut line extending in the circumferential direction of the peripheral portion 21 may be provided, or a strip-shaped film may be arranged by welding so as to extend in the circumferential direction of the peripheral portion 21, and the peripheral portion 21 may be configured to be tearable along the strip-shaped film by pulling the strip-shaped film from the end.

As shown in Figs. 1 and 2A, the packaging bag 1 has an upper cutout portion 5 and a lower main body portion 6 in the vertical direction, with the opening portion 24 as the boundary. By tearing the peripheral surface portion 21 in the circumferential direction at the opening portion 24 and removing the cutout portion 5 above the opening portion 24, the main body portion 6 having an opening 7 is obtained as shown in Fig. 2B. The main body portion 6 is used as a dish when eating the contents in the packaging bag 1.

As shown in FIG. 2A, the opening/closing portion 24 is provided at a position closer to the bottom portion 2 than the opening/closing member 23. In other words, the opening/closing member 23 is provided at the cutout portion 5. Therefore, when the cutout portion 5 is removed during opening, the opening/closing member 23 is also removed. Therefore, the opening/closing member 23 does not get in the way when eating the contents.

The opening section 24 is located closer to the bottom section 2 than the joint section 10. In other words, the joint section 10 is located at the cutout section 5. Therefore, when the cutout section 5 is removed during opening, the joint section 10 is also removed. Therefore, the joint section 10 does not get in the way when eating the contents.

As shown in FIG. 3A, a steam release seal portion 11 is formed on the peripheral portion 21 of the packaging bag 1. In this embodiment, the steam release seal portion 11 is provided on the joint portion 10. The steam release seal portion 11 is a welded portion having a lower weld strength than other welded portions. When the internal pressure of the packaging bag 1 increases due to steam generated inside the packaging bag 1 by heating the packaging bag 1, a steam flow path is formed in the steam release seal portion 11. Steam inside the packaging bag 1 is discharged to the outside through the steam release seal portion 11.

1 and 3B, the bottom portion 2 is provided with a reinforcing member 27 that reinforces the bottom portion 2 so as to suppress curvature of the bottom film 20a. In this embodiment, as shown in FIG. 4, the bottom film 20a is folded into a V shape at the center line E1 and inserted between the front portion 3 and the back portion 4 to form a bag shape, and then the bottom film 20a is unfolded, and a plate-shaped reinforcing member 27 is attached to the entire underside 20a2 of the bottom film 20a (the surface facing the outside of the packaging bag 1 out of the two opposing surfaces of the bottom film 20a) as shown in FIG. 1 and 3B.

As shown in Figures 1 and 3, when the bottom film 20a is unfolded and the reinforcing member 27 is attached, a valley fold 31 is formed in the front portion 3, and the inner surface of the portion below the fold 31 in the front lower portion 3a in the vertical direction of the packaging bag 1 approaches the upper surface 20a1 of the bottom film 20a. In addition, a valley fold 41 (see Figure 6) is formed in the back portion 4, and the inner surface of the portion (back lower portion 4a) below the fold 41 in the back portion 4 in the vertical direction of the packaging bag 1 approaches the upper surface 20a1 of the bottom film 20a.

It is preferable that the reinforcing member 27 has a higher rigidity than the bottom film 20a. In this disclosure, rigidity indicates the difficulty of bending a member when a force is applied to bend the member, and can be expressed, for example, by indices such as bending rigidity, elastic modulus (flexural modulus, Young's modulus), and bending strength. By providing the reinforcing member 27, which has a higher rigidity than the bottom film 20a, on the bottom surface portion 2, it is possible to effectively prevent the bottom film 20a from bending in the front-to-rear direction (short direction) so that the bottom surface portion 2 moves away from the grounded surface as the packaging bag 1 expands when heating is performed in a microwave oven with the bottom surface portion 2 grounded and the peripheral surface portion 21 inclined, as described below.

Furthermore, the reinforcing member 27 of this embodiment has flexibility to the extent that it allows the bottom film 20a to bend or bend in the left-right direction (longitudinal direction) as the packaging bag 1 expands and the front portion 3 and the back portion 4 move away from each other in the front-to-back direction. By bending the bottom film 20a in the left-to-right direction, the fold 31 in the front portion 3 and the fold 41 in the back portion 4 can be unfolded as shown in FIG. 2B, and the volume of the sealed space S of the packaging bag 1 expands near the bottom portion 2, improving the self-supporting stability of the packaging bag 1.

The material of the reinforcing member 27 may be any material capable of realizing a high degree of rigidity capable of suppressing the bending of the bottom film 20a, and may be, for example, paper, synthetic paper, plastic, cardboard, nonwoven fabric, foam (e.g., sponge), or a composite material of paper and plastic. Since cardboard and foam have excellent heat insulating properties, when the reinforcing member 27 is made of cardboard or foam, the packaging bag 1 is easy to place on the palm of the hand when used as tableware. When paper is used as the material, it is preferable to use paperboard such as paperboard for paper containers or corrugated board. The thickness of the paper constituting the reinforcing member 27 is, for example, 0.2 mm to 5 mm, preferably 0.3 mm to 3 mm, and more preferably 0.4 mm to 2 mm. Specifically, the thickness may be, for example, any one of 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2.5, 3, 3.5, 4, 4.5, 5 (unit: mm), or may be within a range between any two of the numerical values exemplified here, for example, 0.68 mm. The basis weight of the paper constituting the reinforcing member 27 is, for example, 200 g/ ^m2 or more and 900 g/ ^m2 or less, preferably 250 g/ ^m2 or more and 800 g/ ^m2 or less, and more preferably 300 g/ ^m2 or more and 600 g/m2 or less. Specifically, this basis weight may be, for example, any of the values of 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, or ⁹⁰⁰ (unit: g/m2), or may be within a range between any two of the numerical values exemplified here, for example, 415 g/ ^m2 .

The reinforcing member 27 may be processed to suppress bending of the bottom film 20a in the front-to-rear direction while allowing bending in the left-to-right direction. For example, if paper is used as the material for the reinforcing member 27, creases may be applied near both left and right edges to facilitate mountain folds along the front-to-rear direction, so that the bottom film 20a is bent in the left-to-right direction as the packaging bag 1 expands.

The reinforcing member 27 may be attached to the bottom film 20a with an adhesive. Alternatively, when the reinforcing member 27 is made of plastic or paper with a resin film coated on the attachment surface, it may be attached by welding. The adhesive is preferably a heat-resistant adhesive. In this case, even if the contents become hot due to heating and the heat is transferred to the adhesive, the reinforcing member 27 is prevented from peeling off.

The reinforcing member 27 may be provided on the lower surface 20a2 side of the bottom film 20a as in this embodiment, or on the upper surface 20a1 side (the surface facing the inside of the packaging bag 1 out of the two opposing surfaces of the bottom film 20a). When the reinforcing member 27 is provided on the lower surface 20a2 side, the reinforcing member 27 does not come into contact with the contents, so a wider variety of materials can be used. When the reinforcing member 27 is provided on the upper surface 20a1 side, the reinforcing member 27 may be attached to the bottom film 20a by adhesive or welding, but depending on the shape of the reinforcing member 27, it may be simply placed on the bottom portion 2 without being attached.

The reinforcing member 27 may be provided to cover the entire lower surface 20a2 or the upper surface 20a1 of the bottom film 20a, or may be provided to cover a portion of the lower surface 20a2 or the upper surface 20a1 of the bottom film 20a. From the viewpoint of effectively suppressing the curvature of the bottom film 20a, it is preferable that the reinforcing member 27 is provided at least near both ends of the bottom portion 2 in the left-right direction of the packaging bag 1, and it is more preferable that the reinforcing member 27 is provided at least along the left and right edges of the bottom portion 2.

Furthermore, the reinforcing member 27 is preferably arranged to cover 20% or more of the area of the lower surface 20a2 or the upper surface 20a1 of the bottom film 20a, and more preferably to cover 40% or more. More specifically, the reinforcing member 27 may be any of the values of 20, 30, 40, 50, 60, 70, 80, 90, or 100 (unit: %), or may be within a range between any two of the numerical values exemplified here.

As shown in Figures 3A and 3B, the side ends of the packaging bag 1 are provided with side end welds 12 that weld the front portion 3 and the back portion 4 together. This fixes the front portion 3 and the back portion 4 in the front-to-rear direction. Furthermore, the lower end of the packaging bag 1 is provided with bottom end welds 13 that weld the bottom portion 2 and the front portion 3, and the bottom portion 2 and the back portion 4 together. The bottom end welds 13 weld the bottom portion 2 and the front portion 3, and the bottom portion 2 and the back portion 4 together at the side ends and lower ends of the packaging bag 1 (areas surrounded by dashed lines in Figure 3A).

In the packaging bag 1 shown in FIG. 3A, the vertical length H1 of the cutout portion 5 can be, for example, 6 to 14 cm, and is 10 cm in this embodiment. The vertical length H2 of the main body portion 6 is, for example, 4 to 20 cm, and preferably 6 to 18 cm, and is 7 cm in this embodiment. If the length H2 is too small, the contents may overflow from the main body portion 6 when adding cooking liquid during heating and cooking the food in the packaging bag 1 (for example, when adding water and seasonings to instant noodles and cooking them), and if it is too large, it becomes difficult to remove the contents.

The length H2 is preferably longer than the length H3 (see Figures 3A and 4) from the center line E1 to the bottom end of the bottom film 20a, and more preferably 2 cm or more longer than H3. The value of (H2-H3) is, for example, 2 to 14 cm, and more specifically, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or 14 cm, and may be within a range between any two of the values exemplified here. If the value of (H2-H3) is less than 2 cm, the height of the peripheral wall will be low when the packaging bag 1 is opened, limiting the amount of contents.

Length H3 is preferably 3 to 6 cm, and more specifically, may be any of the values 3, 3.5, 4, 4.5, 5, 5.5, or 6 (unit: cm), or may be within a range between any two of the values exemplified here, for example, 4.5 cm. Since main body 6 is also used as tableware, it is preferable for it to be of this size.

The front portion 3 and back portion 4 constituting the peripheral portion 21 are configured to be inclined integrally to the front or rear side of the packaging bag 1 with respect to the bottom portion 2. With this configuration, the packaging bag 1 can be heated in a microwave oven with the bottom portion 2 on the ground and the peripheral portion 21 inclined, as described below. In this embodiment, as shown in FIG. 6, the front portion 3 and back portion 4 can be inclined integrally to the rear side of the packaging bag 1. At this time, the back portion 4 is folded so that the lower back portion 4a and the upper back portion 4b, which are located respectively below and above the fold line 41, approach each other.

In one example, the front portion 3 is provided with a steam release seal portion 11 (shown in FIG. 3), the bottom portion 2 is unfoldable, and as shown in FIGS. 6 and 8, the peripheral portion 21 is in a state where the bottom portion 2 and the back portion 4 are folded in a valley and laid flat against the bottom portion 2 when the bottom portion 2 is unfolded (i.e., inclined so that the inclination angle with respect to the bottom portion 2 is 30° or less). With this configuration, when the packaging bag 1 is placed in the microwave oven so that the bottom portion 2 is on the ground, the steam release seal portion 11 provided on the front portion 3 is necessarily placed on the upper side of the packaging bag 1, so that the leakage of the contents through the steam flow path formed in the steam release seal portion 11 is suppressed and the contents can be efficiently heated. This inclination angle is, for example, 0° to 30°, preferably 0° to 20°, and more preferably 0° to 10°. More specifically, this inclination angle may be any of the values 0, 5, 10, 15, 20, 25, or 30 (unit: degrees), and may also be within a range between any two of the values exemplified here.

In this embodiment, by closing the opening/closing member 23, the packaging bag 1 is sealed to form a sealed space S inside, and the contents are accommodated in the sealed space S. The upper end E2 of the sealed space S is located near the opening/closing member 23 as shown in FIG. 7A. For example, when the entire surfaces of the bases 23a1 and 23b1 of the opening/closing member 23 are welded to the front part 3 and the back part 4, respectively, the lower ends of the hook parts 23a2 and 23b2 of the opening/closing member 23 become the upper end of the sealed space S. Alternatively, when an unwelded part with the front part 3 is provided from the lower end of the base 23a1 to the upper end of the hook part 23a2 as described above, the sealed space S extends to the unwelded part as the packaging bag 1 expands, so that the upper end of the hook part 23a2 becomes the upper end E2 of the sealed space S. On the other hand, the lower end E3 of the sealed space S is located at the upper end of the part of the lower end welded part 13 provided at the lower end of the packaging bag 1 (in other words, the lower end of the unwelded part of the inner surface of the front part 3) as shown in FIG. 7A.

7A, E4 indicates the center line of the sealed space S in the vertical direction of the packaging bag 1. The packaging bag 1 of this embodiment is configured so that the sum of the weight of the portion of the peripheral surface portion 21 below the center line E4 of the sealed space S and the weight of the bottom surface portion 2 (the weight of the second portion P2 shown in FIG. 7B) is greater than the weight of the portion of the peripheral surface portion 21 above the center line E4 (the weight of the first portion P1 shown in FIG. 7B). In this embodiment, the weight of the bottom surface portion 2 is the sum of the weight of the bottom film 20a and the weight of the reinforcing member 27. If the weight of the first portion P1 is W1 and the weight of the second portion P2 is W2, W2/W1 is, for example, 1.1 to 10, preferably 1.5 to 7, and more specifically, for example, any of the values 1.1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, and 10, or may be within a range between any two of the numerical values exemplified here.

Moreover, it is more preferable that the sum of the weight of a part of the front surface portion 3 located below the center line E1 of the bottom film 20a in a plan view of the packaging bag 1 and the weight of a part of the bottom surface portion 2 located below the center line E1 of the bottom film 20a in a plan view of the packaging bag 1 (the weight of the third portion P3 shown in FIG. 7A) is greater than the weight of the part of the peripheral surface portion 21 above the center line E4 (the weight of the first portion P1). If the weight of the third portion P3 is W3, W3/W1 is, for example, 1.1 to 8, preferably 1.5 to 5, and more specifically, for example, any of the values 1.1, 1.5, 2, 3, 4, 5, 6, 7, and 8, or may be within a range between any two of the numerical values exemplified here.

By configuring the packaging bag 1 so that the first portion P1, the second portion P2, and the third portion P3 have the above-mentioned size relationship, when the packaging bag 1 expands and is heated in a microwave oven with the bottom portion 2 on the ground and the peripheral portion 21 inclined, as described below, it is possible to effectively prevent the bottom portion 2 from bending away from the grounded surface.

By adjusting the weight of the reinforcing member 27, it is possible to configure the packaging bag 1 so that the first portion P1, the second portion P2, and the third portion P3 have the above-mentioned size relationship. In such a configuration, the reinforcing member 27 reinforces the bottom surface portion so as to suppress the curvature of the bottom film 20a by its weight. In this case, the reinforcing member 27 may have a higher rigidity than the bottom film 20a as described above, or may have a rigidity equal to or less than that of the bottom film 20a.

The bottom film 20a and the peripheral wall film 20b constituting the peripheral portion 21 are preferably laminated films having a base layer and a sealant layer, and more preferably have an adhesive layer and a printed layer between the base layer and the sealant layer. In addition, films having the same configuration and physical properties may be used for the bottom film 20a and the peripheral wall film 20b, or films having different configurations and physical properties may be used.

The base layer is arranged so as to be exposed on the outer surface of the packaging bag 1, and the sealant layer is arranged so as to be exposed on the inner surface of the packaging bag 1. The sealant layers are welded (heat sealed) together to form a welded portion.

The substrate layer is formed of a material having excellent strength and high impact resistance. For example, polyamide, polyolefin, polyethylene, polyester, etc. can be used as the substrate layer. More specifically, stretched polyethylene terephthalate film, silica-deposited stretched polyethylene terephthalate film, alumina-deposited stretched polyethylene terephthalate film, stretched nylon film, stretched polypropylene film, polypropylene/ethylene-vinyl alcohol copolymer co-extruded co-stretched film, etc. can be used. As the film constituting the substrate layer, one having linear cutability in the MD direction (the direction in which the film flows during production) is preferable. The substrate layer, which is the outermost layer, may contain an antibacterial or antiviral agent (silver ions, etc.). In particular, by kneading a bleed-out antibacterial or antiviral agent into the substrate layer, the antibacterial or antiviral treatment of the surface of the substrate layer progresses when it is heated in a microwave oven and reaches a high temperature, making it hygienic to remove from the microwave oven.

The adhesive layer is a layer for bonding the base layer and the sealant layer together. The bonding method may be, for example, extrusion lamination using polyethylene or the like as an adhesive layer, or dry lamination using a polyvinyl acetate adhesive, a polyacrylic ester adhesive, a cyanoacrylate adhesive, an ethylene copolymer adhesive, a cellulose adhesive, a polyester adhesive, a polyamide adhesive, an amino resin adhesive, an epoxy adhesive, a polyurethane adhesive, or the like as an adhesive.

The sealant layer can be formed from a resin with excellent weldability. The sealant layer can be formed from a polyolefin resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, or ethylene-propylene block copolymer, and more specifically, unstretched polypropylene or linear low-density polyethylene can be used. The film constituting the sealant layer is preferably one that has linear cutability in the MD direction.

It is preferable to use a film in which the first and second base material layers as base material layers and a sealant or the like are laminated in this order via an adhesive layer as the peripheral wall film 20b, and to apply an easy-tear treatment to the entire second base material layer and part of the sealant layer in at least one of the opening portion 24 and the upper opening portion 26. This makes it easier to tear the packaging bag 1 straight at the opening portion 24 and the upper opening portion 26. In particular, even when a peripheral wall film 20b with linear cutting properties is used for the opening portion 24, the problem of it being easier to tear straight due to heating in a microwave oven is likely to occur. By applying the easy-tear treatment as described above, it is possible to eliminate such a problem even after heating in a microwave oven.

The easy-tear processing is, for example, perforation processing. When perforation processing is performed, perforations are formed in the entire second base material layer and part of the sealant layer along the extension direction (left-right direction) of the opening portion 24 and the upper opening portion 26. In this case, it is preferable that the sealant layer is cut from the surface of the second base material layer side of the sealant layer to 5 to 80% of the thickness of the sealant layer in the thickness direction of the film, and it is more preferable that the sealant layer is cut to 30 to 60%. The shape of the perforation may be a broken line parallel to the extension direction of the opening portion 24 and the upper opening portion 26, a curved shape extending along the extension direction, or a shape in which multiple straight lines inclined with respect to the extension direction are aligned along the extension direction. Also, multiple rows of perforations may be formed along the extension direction.

The length H4 in the left-right direction at the bottom end of the packaging bag 1 shown in Figure 3A is preferably 10 to 25 cm, and more preferably 18 cm or more, from the viewpoint of a size that can be placed on the turntable of a microwave oven. More specifically, it may be any of the values 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25 (unit: cm), for example, or may be within a range between any two of the values exemplified here, for example, 20 cm.

1.2. Cooking method of packaged food Next, a cooking method of packaged food in which food is contained in the packaging bag 1 of this embodiment will be described with reference to Figures 8A to 8C. Packaged foods include (1) foods that are pre-packaged in the packaging bag 1 at a factory and can be cooked without the consumer having to put additional ingredients in the packaging bag 1 (such as retort foods and frozen foods), (2) foods that are pre-packaged in the packaging bag 1 at a factory and can be cooked after the consumer has put additional ingredients in the packaging bag 1, and (3) foods that do not contain a product in the packaging bag 1 and can be cooked after the consumer puts the food in the packaging bag 1. In the case of (1) above, it is preferable to seal the packaging bag 1 after putting the food in the packaging bag 1 at a factory. In this case, the opening and closing member 23 can be omitted.

The cooking method includes a heating step. In the case of (2) or (3) above, a containing step is included before the heating step. Figures 8A to 8C are explanatory diagrams of a cooking method for a packaged food in which food is contained in a packaging bag 1, and are schematic diagrams of the D-D cross section in Figure 6 (a cross section passing through the center of the packaging bag 1 in the left-right direction and parallel to the front-rear direction).

In the containing step, food or additional ingredients are contained in the packaging bag 1. The food is, for example, instant noodles, and the additional ingredient is, for example, cooking liquid. In this case, in the containing step, the cooking liquid is contained in the packaging bag 1 so that it comes into contact with the food, and the packaging bag 1 is sealed. For example, if the food is instant noodles, water or liquid seasoning is contained as the cooking liquid so that it comes into contact with the instant noodles. In this embodiment, the opening and closing member 23 of the packaging bag 1 is opened and the cooking liquid is contained in the packaging bag 1 through the opening 22. After the cooking liquid is contained, the opening and closing member 23 is closed to seal the packaging bag 1. Note that if there is no need to add cooking liquid when cooking the food, the containing step does not need to be performed.

In the heating step, the packaged food is heated in a microwave oven. If cooking liquid is added in the containing step, the food and cooking liquid contained in the packaging bag 1 are heated in the microwave oven. At this time, as shown in FIG. 8A, the bottom surface 2 is grounded in the microwave oven and the peripheral surface 21 is inclined (i.e., laid down) so that the inclination angle θ with respect to the horizontal plane is 30° or less, and heating of the food contained in the packaging bag 1 is started in the microwave oven. In this embodiment, the bottom surface 2 is grounded on a substantially horizontal surface G such as a turntable inside the microwave oven. Microwave ovens are generally designed to concentrate microwaves in the lower center of the oven, and by starting heating with the peripheral surface 21 laid down, it is possible to efficiently heat the food in the packaging bag 1.

The inclination angle θ refers to the smaller angle between the peripheral portion 21 and the horizontal plane. In addition, when the peripheral portion 21 is inclined and the front portion 3 and the back portion 4 constituting the peripheral portion 21 are separated due to the presence of contents, the inclination angle θ refers to the angle between the lower one of the front portion 3 and the back portion 4 and the horizontal plane. In this embodiment, the inclination angle θ is the angle between the upper back portion 4b of the back portion 4 and the horizontal plane, and specifically, as shown in FIG. 8A, the inclination angle θ is the angle between the horizontal plane and a straight line L connecting the upper end of the back portion 4 and the fold 41 in the vertical direction of the packaging bag 1. In addition, the state in which the peripheral portion 21 is inclined so that the inclination angle θ is 30° or less also includes a state in which the peripheral portion 21 is completely laid down so that the inclination angle is 0° (in other words, so that the peripheral portion 21 is horizontal).

The inclination angle θ is, for example, 0° or more and 30° or less, preferably 0° or more and 20° or less, and more preferably 0° or more and 10° or less. More specifically, the inclination angle θ may be, for example, any of the values 0, 5, 10, 15, 20, 25, and 30 (unit: degrees), and may be within a range between any two of the numerical values exemplified here.

The peripheral surface portion 21 may be inclined toward either the front or rear side of the packaging bag 1, but is preferably inclined toward the side of the front portion 3 or rear portion 4 where the steam release seal portion 11 is not provided (the rear portion 4 side in this embodiment). In this case, the peripheral surface portion 21 is inclined so that the steam release seal portion 11 faces upward, so that the release of steam from the steam release seal portion 11 during heating is less likely to be hindered.

In this embodiment, the front portion 3 and the back portion 4 are integrally inclined rearward relative to the bottom portion 2. By inclining the peripheral portion 21, the food in the packaging bag 1 can come into contact with the cooking liquid over a wider area, enabling efficient cooking. In particular, in the case of food that has a relatively flat shape, such as instant noodles, a wider area can come into contact with the cooking liquid compared to when the peripheral portion 21 is not inclined.

When heating is started, the packaging bag 1 expands as the internal pressure of the packaging bag 1 increases, and a steam flow path is formed in the steam release seal portion 11 to discharge steam. At this time, the internal pressure increases from the state shown in FIG. 8A, and the front portion 3 is pressed upward from the inside, applying a force to the bottom film 20a constituting the bottom portion 2 to bend its front end portion upward. In this embodiment, the reinforcing member 27 provided on the bottom portion 2 suppresses the bending of the bottom film 20a in the front-to-rear direction, and the bottom portion 2 is maintained in a state where it is grounded on the surface G during the heating process. In addition, the peripheral portion 21 rises as the packaging bag 1 expands, and the contents gradually gather near the bottom portion 2, so that the weight of the contents further suppresses the bending of the bottom portion 2 in the front-to-rear direction.

When steam is generated near the bottom portion 2 of the packaging bag 1 due to heating, the portion of the front portion 3 on the bottom portion 2 side expands, which applies a force that bends the front end side of the bottom portion 2 upward. In this embodiment, in addition to the reinforcing member 27 suppressing the bending of the bottom film 20a, the weight of the second portion P2 located below the center line E4 of the sealed space S in the packaging bag 1 is greater than the weight of the first portion P1 located above the center line E4, so that the front end side of the bottom portion 2 is suppressed from floating upward. In addition, as the packaging bag 1 expands, the peripheral portion 21 rises, the contents gradually gather near the bottom portion 2, and the steam moves toward the upper part of the packaging bag 1, which further suppresses the bending of the bottom portion 2 as described above.

When the packaging bag 1 further expands, the front portion 3 and the back portion 4 move away from each other in the front-rear direction and the side ends approach each other, so that a force is applied to the bottom film 20a to bend both its left and right edges upward. In this embodiment, the reinforcing member 27 has a degree of flexibility that allows the bottom film 20a to bend in the left and right direction, so that the bottom film 20a bends in the left and right direction, and the fold 31 of the front portion 3 and the fold 41 of the back portion 4 unfold as shown in FIG. 8B. As a result, the peripheral portion 21 rises upward from a state inclined toward the rear. Then, when heating is completed, the peripheral portion 21 becomes upright relative to the bottom portion 2 as shown in FIG. 8C. In this way, the peripheral portion 21 is displaced during heating, and the contents are also displaced during this displacement, so that the contents are stirred and the distribution of the microwaves irradiated to the contents changes, thereby improving the uniformity of heating.

After heating is complete, the packaging bag 1 preferably stands on its own with the bottom portion 2 facing down. In this case, after heating is complete, the packaging bag 1 can be easily removed from the microwave oven in a self-supporting state. In addition, by opening the self-supporting packaging bag 1 at the opening portion 24, the food inside can be eaten using the packaging bag 1 as a dish.

1.3 Manufacturing Method of Packaging Bag Next, a manufacturing method of the packaging bag 1 with the reinforcing member 27 of this embodiment will be described. The manufacturing method includes a reinforcing member attachment step. In the reinforcing member attachment step, the reinforcing member 27 is attached to the bottom portion 2 of the packaging bag 1 in a state where the bottom portion 2 is unfolded.

The packaging bag 1 can be manufactured by a bag-making process. In the bag-making process, the packaging bag 1 is manufactured from a flexible film. First, as shown in FIG. 9A, the inner faces of the ends of one peripheral wall film 20b are overlapped to form an overlapping portion 10a, and as shown in FIG. 9B, the overlapping portion 10a is welded to form a seam portion 10, and the remaining portion forms an elliptical ring C.

Next, as shown in Figures 9A to 9B, one end C1 of the ring C is cut and a bottom film 20a bent into a V shape at the center line E1 is inserted. Next, as shown in Figures 9B to 10A, the bottom film 20a and the peripheral wall film 20b are welded together and the other end C2 of the ring C is cut off to form the bottom portion 2, the front portion 3, and the back portion 4.

Next, as shown in FIG. 10B, near the other end C2 of the ring C (near the upper ends of the front portion 3 and the back portion 4), an opening/closing member 23 is inserted between the front portion 3 and the back portion 4, and the opening/closing member 23 is welded to the inner surfaces of the front portion 3 and the back portion 4, and the upper ends of the front portion 3 and the back portion 4 are welded together, thereby producing the packaging bag 1. Note that the contents, such as food, may be filled during the bag making process, or may be filled into the packaging bag 1 after the bag is made.

In the reinforcing member attachment process, a reinforcing member 27 is provided on the bottom surface 2 of the manufactured packaging bag 1. In the present embodiment, which is an example, the folded bottom film 20a is unfolded, and the reinforcing member 27 is attached to the lower surface 20a2 side by adhesive or welding. When the reinforcing member 27 is provided on the upper surface 20a1 side of the bottom film 20a, the reinforcing member 27 may be attached by adhesive or welding to the bottom film 20a of the packaging bag 1 after the bag is manufactured and before the contents are filled, or the reinforcing member 27 may be inserted into the packaging bag 1 without being attached and placed on the bottom surface 2.

It is preferable that the reinforcing member attachment process is performed after the bag making process. It is possible to attach the reinforcing member 27 to the bottom film 20a before the bag making process and then perform the bag making process, but in that case, the bag making process may become difficult to perform, so it is preferable that the reinforcing member attachment process is performed after the bag making process. In addition, when attaching the reinforcing member 27, it is preferable that the bottom surface portion 2 is unfolded and the peripheral surface portion 21 is laid down. In this case, it is easier to attach the reinforcing member 27.

In addition, if the process includes a content filling step in which the contents are filled and sealed in the packaging bag 1, the reinforcing member attachment step may be performed before or after the content filling step. Performing the reinforcing member attachment step before the content filling step has the advantage that the reinforcing member 27 is easier to attach. On the other hand, if the reinforcing member 27 is attached before the content filling step, it may be difficult to fill the contents depending on the device used in the content filling step. In that case, it is preferable to perform the reinforcing member attachment step after the content filling step.

2. Second embodiment Next, a packaging bag 1 according to a second embodiment of the present invention will be described with reference to Figures 11A to 12. The packaging bag 1 according to the second embodiment differs from the first embodiment in that the reinforcing member 27 has a high rigidity sufficient to suppress curvature of the bottom film 20a in the left-right direction in addition to the front-rear direction. The following description will focus on the differences from the first embodiment.

Figures 11A to 11C are explanatory diagrams of a method for cooking a packaged food in which food is contained in a packaging bag 1 according to the second embodiment. When the packaging bag 1 expands due to heating from the state shown in Figure 11A, the reinforcing member 27 suppresses the bending of the bottom film 20a in the front-to-rear direction, as in the first embodiment. When the packaging bag 1 expands further and the front portion 3 and the back portion 4 move away from each other in the front-to-rear direction and the side ends approach each other, a force is applied to the bottom film 20a to bend both left and right edges upward.

At this time, in this embodiment, the reinforcing member 27 suppresses the left-right curvature of the bottom film 20a, and the bottom portion 2 is maintained in contact with the surface G. Therefore, as shown in FIG. 11B, the front portion 3 and the back portion 4 expand above the folds 31, 41 of the packaging bag 1 while maintaining the folds 31, 41, and the peripheral portion 21 rises upward from its rearward inclined state. Then, when heating is completed, the portion of the peripheral portion 21 above the folds 31, 41 stands upright relative to the bottom portion 2, as shown in FIG. 11C.

After heating, the peripheral portion 21 is torn in the circumferential direction at the opening portion 24 to remove the cut-out portion 5, thereby obtaining the main body portion 6 having the opening 7 as shown in FIG. 12. The reinforcing member 27 suppresses the bending of the bottom film 20a in the front-rear and left-right directions, allowing the entire underside of the bottom portion 2 to be placed on the ground and the packaging bag 1 to stand on its own. When using the packaging bag 1 as tableware to eat the contents, the reinforcing member 27 may be bent or folded in the left-right direction (longitudinal direction) to unfold the creases 31, 41. This expands the volume inside the packaging bag 1 near the bottom portion 2, improving its stability.

3. Third embodiment The shape and arrangement of the reinforcing member 27 are not limited to those in the above-described embodiment. Modifications of the reinforcing member 27 will now be described.

The shape of the reinforcing member 27 is arbitrary, and can be, for example, a plate, a film, a rod, a tube, etc. The planar shape of the reinforcing member 27 in the case of a plate or film shape, and the cross-sectional shape of the outer surface of the reinforcing member 27 in the case of a rod or tube shape, can be polygonal (e.g., quadrilateral such as a rectangle, a square, or a trapezoid) or curved (elliptical, oval, circular, etc.). In one example, the reinforcing member 27 can be elliptical as shown in FIG. 13A. The reinforcing member 27 can also be shaped to follow the inner edge 2j of the lower end welded portion 13 provided on the bottom surface portion 2 as shown in FIG. 14.

The arrangement of the reinforcing member 27 and the number of members can be changed as appropriate. As an example, the reinforcing member 27 may be a rectangular frame shape arranged along the periphery of the bottom film 20a. As another example, the reinforcing member 27 may be composed of multiple members. For example, as shown in FIG. 13B, the reinforcing member 27 may be composed of two long plate-shaped members arranged along the left and right edges of the bottom portion 2, or three long plate-shaped members arranged along the left and right edges of the bottom portion 2 and the center of the bottom portion 2 in the left and right direction. In addition, the reinforcing member 27 may be provided near the center of the bottom portion 2 in the left and right direction of the packaging bag 1, as shown in FIG. 13C. Furthermore, the reinforcing member 27 may be provided near the center of the bottom portion 2 in the front-rear direction of the packaging bag 1, as shown in FIG. 13D. In this case, it is preferable that the reinforcing member 27 has an elongated shape extending in the left-right direction of the packaging bag 1. In this case, the balance of the front-rear direction of the packaging bag 1 is improved, so that the self-supporting property of the packaging bag 1 is easily improved.

Also, eating utensils such as chopsticks (e.g., disposable chopsticks), spoons, and forks may be used as the reinforcing member 27. In this case, after cooking the food in the packaging bag 1, the eating utensils can be removed from the packaging bag 1 and used to eat the food. In one example, the reinforcing member 27 is disposable chopsticks 27a, as shown in FIG. 15, and openings 2f may be provided in the protruding pieces 2e provided on the front edge 2c and the rear edge 2d of the bottom part 2, and the disposable chopsticks 27a may be inserted into the pair of openings 2f to be placed on the bottom part 2. In this case, the disposable chopsticks 27a are detachable from the bottom part 2, and for example, when the contents of the packaging bag 1 are heated, the disposable chopsticks 27a are inserted into the openings 2f to function as the reinforcing member 27, and after heating is completed, the disposable chopsticks 27a can be removed from the openings 2f and used to eat the contents. Instead of providing the openings 2f on the protruding pieces 2e, the openings 2f may be provided by forming cuts or holes in the lower end welding part 13, as shown in FIG. 16. The method of holding the disposable chopsticks 27a shown here can also be applied to reinforcing members 27 other than the disposable chopsticks 27a.

The reinforcing member 27 can be attached by any method. Methods for attaching the reinforcing member 27 to the bottom surface portion 2 include adhesion, bonding, welding, clamping, engagement, and the like. In one example, the reinforcing member 27 can be attached to the bottom surface portion 2 using a fixing means 29 such as adhesive tape, adhesive, or clips, as shown in FIG. 17.

In one example, the reinforcing member 27 can be formed of a reinforcing member film 20d having the same structure as the bottom film 20a, as shown in FIG. 18A. In this case, the reinforcing member film 20d as the reinforcing member 27 and the bottom film 20a can be attached to the bottom surface portion 2 by joining the reinforcing member film 20d as the reinforcing member 27 and the bottom film 20a at the welding portions 20i provided at the front edge 20f and the rear edge 20g, respectively. As a result, as shown in FIG. 18B, a packaging bag 1 is obtained in which the reinforcing member film 20d is superimposed on the bottom film 20a constituting the bottom surface portion 2. In this case, a pocket 20h is formed between the bottom film 20a and the film 20d, and another reinforcing member may be inserted into this pocket 20h. Note that the tubular film may be flattened and treated as a film in which the bottom film 20a and the reinforcing member film 20d are joined at the front edge 20f and the rear edge 20g.

The reinforcing member 27 may be pre-attached to the bottom portion 2 at the factory, or the reinforcing member 27 and the packaging bag 1 may be separate at the time of factory shipment, and the consumer may attach the reinforcing member 27 to the bottom portion 2. In the latter case, there is an advantage that the consumer can choose whether or not to attach the reinforcing member 27 to the bottom portion 2. The packaging bag 1 and the reinforcing member 27 can be packaged together using an outer packaging body 32 as shown in Figures 26 to 27.

In one example, retort food or frozen food in which food is sealed in a packaging bag 1 may be cooked in a water bath in addition to a microwave oven. In such a case, if the reinforcing member 27 is made of a material that is not water resistant, there is a problem that the food cannot be cooked in a water bath if the reinforcing member 27 is pre-attached to the bottom part 2. On the other hand, if the reinforcing member 27 is configured to be selectable by the consumer as to whether or not to attach the reinforcing member 27 to the bottom part 2, cooking in a water bath can be performed even if the reinforcing member 27 is made of a material that is not water resistant by choosing not to attach the reinforcing member 27 to the bottom part 2. From another perspective, if the reinforcing member 27 is pre-attached to the bottom part 2, it is necessary to form the reinforcing member 27 from a material that is water resistant in order to enable cooking in a water bath. However, by making the reinforcing member 27 separate from the packaging bag 1, it becomes possible to form the reinforcing member 27 from a material that is not water resistant, and the manufacturing cost of the reinforcing member 27 can be reduced.

In addition, it is preferable that the reinforcing member 27 is detachable from the packaging bag 1. In this case, the food in the packaging bag 1 can be cooked with the reinforcing member 27 attached to the packaging bag 1, and then the reinforcing member 27 can be removed and attached to another packaging bag 1, and the food in the packaging bag 1 can be cooked. By repeatedly using the reinforcing member 27, it is possible to reduce the manufacturing cost of the packaging bag 1 with the reinforcing member 27. Examples of a configuration for making the reinforcing member 27 detachable from the packaging bag 1 include a method of attaching the reinforcing member 27 to the packaging bag 1 with a releasable adhesive tape, holding the reinforcing member 27 to the packaging bag 1 using an openable and closable holding member such as a clip, and engaging the reinforcing member 27 with an engaging portion provided on the packaging bag 1. Examples of a configuration for engaging the reinforcing member 27 with the engaging portion include a configuration in which the reinforcing member 27 is accommodated in a pocket (such as the pocket 20h in FIG. 18) provided on the bottom surface portion 2, and a configuration in which the reinforcing member 27 is inserted through the opening 2f as shown in FIG. 15 or FIG. 16.

Furthermore, the reinforcing member 27 may be provided so as to be contained within the bottom surface portion 2, or may be provided so as to protrude from the bottom surface portion 2 as shown in FIG. 19. When the reinforcing member 27 protrudes from the bottom surface portion 2, it is preferable that the reinforcing member 27 protrudes on the side where the peripheral surface portion 21 is inclined. In this case, since the reinforcing member 27 overlaps the peripheral surface portion 21 in a plan view, the overall size of the packaging bag 1 with the reinforcing member 27 is unlikely to increase even if the reinforcing member 27 protrudes. In addition, when the packaging bag 1 is heated in a sealed state with food placed therein, the inclined peripheral surface portion 21 tends to stand up. At that time, a downward torque is applied to the portion 2g of the bottom surface portion 2 on the side where the peripheral surface portion 21 is inclined, which tends to rotate the bottom surface portion 2, but by having the reinforcing member 27 protrude from the bottom surface portion 2, the downward torque can be easily withstood, and the peripheral surface portion 21 is more likely to stand upright when heated. Furthermore, the protruding portion does not heat up easily even after the contents are heated, making it easy to grasp the protruding portion and pull the packaging bag 1 out of the microwave oven.

Furthermore, as shown in FIG. 20, fixing means 29 (e.g., adhesive means such as double-sided tape 29a) may be provided on the bottom portion 2, and the fixing means 29 may be used to fix the bottom portion 2 to a general-purpose member 30 (a member that is not prepared as the reinforcing member 27), and this general-purpose member 30 may be used as the reinforcing member 27. Examples of the general-purpose member 30 include tableware such as a plate 30a, a plate placed inside the microwave oven, or the floor surface of the oven.

4. Fourth embodiment Among various aspects constituting the present invention, in a viewpoint where the reinforcing member 27 is not essential, the reinforcing member 27 may be omitted. In the above-described embodiment, the reinforcing member 27, which is a separate member, is provided by, for example, attaching it to the bottom film 20a constituting the bottom portion 2, but in a viewpoint where the reinforcing member 27 is not essential, the reinforcing member 27 may be omitted.

In this case, the bottom part 2 itself may be made of a member having a rigidity such that it does not bend at least in the front-rear direction as the packaging bag 1 expands. For example, as shown in FIG. 21A, the bottom part 2 can be made of a plate-like member 42 having a relatively high rigidity. In this case, in the bag-making process of the manufacturing method of the packaging bag 1, in the peripheral wall film 20b in which one end C1 of the ring C is cut as shown in FIG. 9B, as shown in FIG. 21A, the lower end parts 20j of the two films facing each other at the cut point are folded outward by 90 degrees by a length H3. Then, by folding, both inner surfaces of the two films face downward, and the plate-like member 42 constituting the bottom part 2 is fixed to these inner surfaces, so that the packaging bag 1 can be made into a bag shape. The two films become the front part 3 and the back part 4, respectively. The plate-like member 42 is preferably made of resin. In addition, the plate-like member 42 can be fixed to the film by welding. In addition, as shown in FIG. 21B, the bottom film 20a may be fixed to the back side of the plate-like member 42. In this case, the plate-like member 42 functions as a reinforcing member that suppresses bending of the bottom film 20a.

5. Fifth Embodiment In the fifth embodiment, a modified example of the steam release seal portion 11 will be described.

The steam release seal portion 11 may have any configuration that forms a steam flow path as the internal pressure of the packaging bag 1 increases. In the first embodiment, the steam release seal portion 11 is provided at the gable portion 10, but it is not essential to provide the gable portion 10 on the packaging bag 1. The steam release seal portion 11 may be provided, for example, at the upper end welded portion 19 as shown in FIG. 22A, or at the side end welded portion 12 as shown in FIG. 22B. The steam release seal portion 11 may also be provided so as to protrude from the inner edge 12a of the side end welded portion 12 as shown in FIG. 22C. When the steam release seal portion 11 is provided at the upper end welded portion 19, it is preferable that the opening and closing member 23 is left open or that the packaging bag 1 does not have an opening and closing member 23. When the steam release seal portion 11 is provided at the upper end welded portion 19 or the side end welded portion 12, the shape of the steam release seal portion 11 may be a substantially V-shape tapered toward the inside of the packaging bag 1, as in the first embodiment, or may be another shape.

The steam release seal portion 11 may also be provided at a location other than the upper end welded portion 19 or the side end welded portion 12. For example, as shown in FIG. 23, the front portion 3 and the back portion 4 may be welded into a doughnut shape to form a doughnut-shaped steam release seal portion 11a, and a ventilation portion 11c such as a cut or notch may be provided in the unwelded portion 11b in the center of the doughnut-shaped steam release seal portion 11a. In this case, as the internal pressure of the packaging bag 1 increases, the doughnut-shaped steam release seal portion 11a at least partially peels off to form a steam flow path, and steam is discharged to the outside through the ventilation portion 11c.

In addition, instead of providing the steam release seal portion 11, an opening that prevents the contents from leaking but allows steam to escape may be provided in the packaging bag 1. Such an opening may be formed, for example, by slightly tearing the peripheral portion 21 before heating begins.

6. Sixth Embodiment In the sixth embodiment, a modified example of the method for cooking prepackaged food will be described.

In the above embodiment, the case where the peripheral portion 21 stands upright when heating is complete has been described, but from the viewpoint of various aspects constituting the present invention, where the peripheral portion 21 standing upright is not essential, the peripheral portion 21 does not have to stand upright when heating is complete, but it is preferable that the bottom portion 2 is unfoldable. When the bottom portion 2 is unfoldable, heating with the bottom portion 2 unfolded and in contact with the ground makes it easier for the food contents to move within the packaging bag 1, making it easier to reduce uneven heating. In addition, after heating is complete, the bottom portion 2 can be unfolded and in contact with the ground to make it easier to use the packaging bag 1 as tableware.

Furthermore, among the various aspects constituting the present invention, in the viewpoint that it is not essential to ground the bottom surface portion 2 when heating starts, it is not necessary to ground the bottom surface portion 2 when heating starts, but it is preferable that the peripheral surface portion 21 is upright when heating is completed. Even in this case, uneven heating of the food contents is likely to be reduced by the displacement of the peripheral surface portion 21 during heating.

7. Seventh Embodiment In the seventh embodiment, a modified example of the method for manufacturing the packaging bag 1 will be described.

In the first embodiment, the packaging bag 1 was manufactured using a bottom film 20a and a peripheral wall film 20b, but in the method of this embodiment, the packaging bag 1 can be manufactured using a single film 20c.

First, as shown in FIG. 24A, the inner faces of the ends of one film 20c are overlapped to form an overlapping portion 28, and as shown in FIG. 24B, the inner faces of the overlapping portion 28 are welded to form a first bottom portion 2a, and the remaining portion forms a ring D.

Next, as shown in Figures 24B to 25, the inner surfaces of the film 20c are welded together at a portion D1 of the ring D adjacent to the first bottom portion 2a to form the second bottom portion 2b, and the portion corresponding to the side end weld portion 12 is welded. In addition, the film 20c is cut at an end D2 of the ring D opposite the second bottom portion 2b.

The above steps result in the packaging bag 1. If the film 20c is long, a step of separating the packaging bag 1 from the film 20c is performed to obtain a separated packaging bag 1. The packaging bag 1 can be separated from the film 20c, for example, by cutting the film 20c along the side end welded portion 12. The first bottom portion 2a and the second bottom portion 2b may be formed simultaneously, and then the side end welded portion 12 may be formed.

In the packaging bag 1 obtained by the method of the first embodiment, the bottom film 20a is folded in half immediately after production, so the bottom portion 2 needs to be unfolded in order to attach the reinforcing member 27. On the other hand, in the packaging bag 1 obtained by the method of this embodiment, the bottom portion 2 composed of the first and second bottom portions 2a, 2b is in an unfolded state, so there is an advantage in that the work of unfolding the bottom portion 2 is not necessary. In addition, with the method of this embodiment, the packaging bag 1 can be produced using a single film 20c, so the production equipment can be simplified compared to the method of the first embodiment.

In the above description, the steam release seal portion 11 is omitted, but the steam release seal portion 11 can be formed in the same manner as in the first and fifth embodiments. In addition, it is preferable that the steam release seal portion 11 is provided in a portion other than the joint portion 10, as described in the fifth embodiment.

8. Eighth Embodiment In the eighth embodiment, an outer wrapping body and its modified examples will be described.

An outer packaging body may be provided so as to cover at least a part of the outer surface of the packaging bag 1. For example, the packaging bag 1 may be contained inside an outer packaging body made of a material such as paper or resin and having an overall box shape. By providing the outer packaging body, the packaging bag 1 can be made to stand upright more stably. After cooking, the outer packaging body covering the outer surface of the packaging bag 1 functions as an insulator to prevent the food from cooling down, and the outer packaging body can be easily held in the hand and tilted or lifted even if the food inside the packaging bag 1 is hot. When cooking the packaged food, the food contained in the packaging bag 1 may be heated with the outer packaging body removed, or the food contained in the packaging bag 1 together with the outer packaging body may be heated.

Furthermore, as shown in Figures 26 and 27, an outer packaging body 32 that covers the packaging bag 1 in which the food is enclosed can be used as a reinforcing member 27. Examples of the outer packaging body 32 include a cylindrical outer packaging body 32a as shown in Figure 26A and a box-shaped outer packaging body 32b as shown in Figure 27A.

The cylindrical outer packaging body 32a includes a first covering portion 32a1 that covers the bottom portion 2, and a second covering portion 32a2 that faces the first covering portion 32a1. The bottom portion 2 is fixed to the first covering portion 32a1, or is configured so that it can be fixed by the consumer. The first covering portion 32a1 and the second covering portion 32a2 are connected at both left and right end edges 32a3 to form a cylindrical shape. By cutting the outer packaging body 32a, for example, at the end edge 32a3, the tube opens and the outer packaging body 32a becomes strip-shaped. It is preferable to provide an easy-to-tear portion 32a4 such as a perforation at the portion where the outer packaging body 32a is to be cut.

As shown in FIG. 26B, the strip-shaped outer packaging body 32a can be, for example, folded back at the edge 32a3 to overlap the first covering portion 32a1. In this case, the overlapping first covering portion 32a1 and second covering portion 32a2 can be used as the reinforcing member 27, making it easier to make the packaging bag 1 stand stably. Note that only the first covering portion 32a1 may be used as the reinforcing member 27, without using the second covering portion 32a2.

In another embodiment, the first covering portion 32a1 and the second covering portion 32a2 may be connected at one edge 32a3 and not connected at the other edge 32a3. In this case, the outer packaging body 32a is originally belt-shaped. In this case, it is preferable that the second covering portion 32a2 is fixed to the packaging bag 1 to prevent the second covering portion 32a2 from dangling. In this case, the second covering portion 32a2 can be folded back by releasing the fixation between the second covering portion 32a2 and the packaging bag 1.

The box-shaped outer packaging body 32b contains the packaging bag 1 therein. The bottom part 2 of the packaging bag 1 is preferably fixed to the bottom surface of the outer packaging body 32b or configured to be fixed by the consumer. The outer packaging body 32b is preferably provided with an easy-to-tear part 32b1 such as a perforation, which makes it easy to open the outer packaging body 32b as shown in FIG. 27B. Since the outer packaging body 32b functions as a reinforcing member 27, the outer packaging body 32b can be opened and placed in a microwave oven with the upper part 32b2 open for heating and cooking.

1. Manufacturing method of packaging bag According to the method shown in the first embodiment, a packaging bag 1 having the shape shown in Figures 1 to 3 was manufactured. The dimensions H1 to H4 in Figure 3 were 95 mm, 75 mm, 45 mm, and 20 mm, respectively. The reinforcing member 27 was made of paper with the same shape as the bottom surface portion 2 and a thickness of 0.68 mm, and was attached to the bottom surface portion 2 with double-sided tape.

2. Heating test of water After 200 ml of water at 5°C was put in the packaging bag 1 and sealed, it was heated at 500 W in a microwave oven, and the time before boiling was measured. The time was measured for each of the following cases: the packaging bag 1 was always kept standing ("vertical"), the packaging bag 1 was always kept lying down ("horizontal"), and the bottom part 2 of the packaging bag 1 was placed on the ground and the peripheral part 21 was kept lying down, and the peripheral part 21 was made to stand upright as the packaging bag 1 expanded ("rise"). For the "horizontal" case, the heating time was measured for both the packaging bag 1 placed directly on the plate inside the microwave oven ("normal") and the packaging bag 1 placed on a pedestal with a height of 60 mm provided on the plate ("60 mm above"). The results are shown in Table 1.

As shown in Table 1, in the "normal" position, the "vertical" position took much longer to heat up to boiling than the "horizontal" and "Rise" positions. This result shows that the "vertical" position has inferior heating efficiency compared to the "horizontal" and "Rise" positions. Also, the "60 mm above" position took much longer to heat up to boiling than the "normal" position. This result shows that the microwave oven has particularly excellent heating efficiency near the plate.

3. Food Heating Test Next, a hamburger steak (180 g) or fried rice (130 g) was placed in the packaging bag 1 and stored at the storage temperature shown in Table 2, and then heated in a microwave oven at 500 W for the heating time shown in Table 2. The time until steam escaped from the steam release seal portion 11 ("de-steaming") was measured. In addition, after heating was completed, the temperatures of the parts shown in Table 2 were measured using a thermograph. "Surface (high)" indicates the temperature of the part with the highest temperature on the surface of the food. "Surface (low)" indicates the temperature of the part with the lowest temperature on the surface of the food. "Inside (low)" indicates the temperature of the part with the lowest temperature on a cross section of the hamburger steak when it is divided in two. "Temperature unevenness" indicates the difference between the highest and lowest temperatures among the measured temperatures.

As shown in Table 2, the time until desteaming was much longer in "vertical placement" than in "horizontal placement" and "Rise". This result indicates that "vertical placement" has inferior heating efficiency compared to "horizontal placement" and "Rise". In addition, "horizontal placement" and "Rise" took the same time until desteaming, and "Rise" had smaller temperature unevenness than "horizontal placement". This result shows that "Rise" can reduce temperature unevenness without reducing heating efficiency.

1: Packaging bag 2: Bottom surface portion 2a: First bottom surface portion 2b: Second bottom surface portion 2c: Front edge 2d: Rear edge 2e: Projecting piece 2f: Opening 2g: Part 2j: Inner edge 3: Front surface portion 3a: Front lower portion 3b: Front upper portion 4: Back surface portion 4a: Back lower portion 4b: Back upper portion 5: Cut-out portion 6: Main body portion 7: Opening 10: Joint portion 10a: Overlap portion 11: Steam release seal portion 11a: Donut-shaped steam release seal portion 11b: Unsealed portion 11c: Ventilation portion 12: Side end welded portion 12a: Inner edge 13: Lower end welded portion 19: Upper end welded portion 20a: Bottom film 20a1: Upper surface 20a2: Lower surface 20b: Peripheral wall film 20c: Film 20d: Reinforcing member film 20f : Front edge 20g : Rear edge 20h : Pocket 20i : Welded portion 20j : Lower end 21 : Peripheral surface portion 22 : Opening 23 : Opening/closing member 23a : Front side engaging member 23a1 : Base portion 23a2 : Hook portion 23b : Rear side engaging member 23b1 : Base portion 23b2 : Hook portion 24 : Opening portion 24a : Tear initiation portion 24b : Cut line 26 : Upper side opening portion 26a : Tear initiation portion 26b : Cut line 27 : Reinforcing member 27a : Chopstick 28 : Overlapping portion 29 : Fixing means 29a : Double-sided tape 30 : General-purpose member 30a : Plate 31 : Fold 32 : Outer wrapping body 32a : Outer wrapping body 32a1 : First covering portion 32a2 : Second covering portion 32a3 : Edge 32a4 : Easy to tear portion 32b : Outer wrapping body 32b1 : Easy to tear portion 32b2 : Upper portion 41 : Fold 42 : Plate-like member B : Region C : Ring C1 : One end C2 : Other end P1 : First portion P2 : Second portion P3 : Third portion S : Sealed space D : Ring D1 : Part D2 : End

Claims (4)

1. A method for preparing a packaged food product, comprising:
A heating process is provided.
The packaged food product includes a packaging bag and food contained in the packaging bag.
The packaging bag includes a bottom surface portion and a peripheral surface portion provided so as to rise from the bottom surface portion,
In the heating process, heating of the food contained in the packaging bag is started using a microwave oven with the peripheral portion inclined at an angle of 30° or less with respect to the horizontal plane, and when heating is completed, the peripheral portion is in an upright position. 2. The method of claim 1 ,
Further comprising a containing step,
In the containing step, a cooking liquid is contained in the packaging bag so as to come into contact with the food, and the packaging bag is sealed;
In the heating step, the food and the cooking liquid contained in the packaging bag are heated in a microwave oven. 3. The method of claim 1 or claim 2,
The bottom surface portion is expandable,
The method, wherein the heating step is initiated with the bottom portion deployed and grounded. 3. The method of claim 1 or claim 2,
The bottom surface portion is constituted by a bottom film,
The method, wherein the heating step is initiated with the bottom portion being provided with a reinforcing member that reinforces the bottom portion to inhibit curling of the bottom film.