Packaging bag, and cooking method for packaged food product

Abstract

To provide a packaging bag, invented in consideration of such a circumstance, which can store contents such as a food product, can be heated in a microwave oven easily and efficiently, and can be utilized as a dish after the bag is heated.SOLUTION: A packaging bag according to the present invention is a packaging bag for a microwave oven having a film with flexibility formed therein in a bag shape, which comprises a bottom surface part and a peripheral surface part. The peripheral surface part comprises a front surface part and a back surface part arranged to oppose to each other to stand up from the bottom surface part, where the front surface part and the back surface part are constituted to be able to incline integrally toward a front side or a rear side of the packaging bag with respect to the bottom surface part. The bottom surface part can be expanded.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a packaging bag and a method for preparing a packaged food. [Background technology]

[0002] Packaging bags that can be heated in a microwave oven are known as packaging bags for containing contents such as food. 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 venting means when heated. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-306426 A Summary of the Invention [Problem to be solved by the invention]

[0004] If the packaging bag stands upright, it becomes easier to remove it from the microwave after heating, and the packaging container can be used as tableware. However, microwave ovens are generally designed to concentrate microwaves in the lower center of the oven, so cooking is more efficient when the packaging bag is laid down rather than standing upright.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a packaging bag that can contain food or other contents and be easily and efficiently heated in a microwave oven, and that can be easily used as tableware after heating. [Means for solving the problem]

[0006] According to the present invention, the following inventions are provided. [1] A packaging bag for use in a microwave oven, made of a flexible film 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 extending upward from the bottom portion, the front and rear portions being configured so as to be integrally tiltable toward the front or rear of the packaging bag relative to the bottom portion, and the bottom portion being unfoldable. [2] The packaging bag according to [1], comprising a steam release seal portion that forms a steam flow path as the internal pressure of the packaging bag increases. [3] A packaging bag as described in [1] or [2], comprising an internally sealed space for accommodating contents, and configured such that the sum of the weight of the peripheral portion below the center line of the sealed space in the vertical direction of the packaging bag and the weight of the bottom portion is greater than the weight of the peripheral portion above the center line of the sealed space. [4] A packaging bag according to any one of [1] to [3], wherein the bottom portion is made of a bottom film, and the bottom portion is provided with a reinforcing member that reinforces the bottom portion so as to suppress curvature of the bottom film. [5] The packaging bag according to [4], wherein the reinforcing member can be attached to the bottom portion of another packaging bag after being removed from the bottom portion. [6] A method for cooking a packaged food, comprising a heating step, the packaged food comprising the packaging bag described in any one of [1] to [5] 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 placed on the ground and the peripheral portion inclined so that the inclination angle with respect to the horizontal plane is 30° or less. Effect of the Invention

[0007] The packaging bag according to the present invention is configured such that the front and back parts constituting the peripheral part can be integrally tilted forward or backward with respect to the bottom part. With such a configuration, the packaging bag can be placed in a microwave oven with the peripheral part laid down, and by starting heating in this state, the contents can be efficiently heated. After heating, the bottom part can be unfolded and placed on the ground, making it easy to use as tableware. [Brief description of the drawings]

[0008] [Figure 1] 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 Fig. 2 and subsequent figures. [Diagram 2] 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. [Diagram 3] Fig. 3A is a plan view of the packaging bag 1 in Fig. 1 in a flattened state, and Fig. 3B is a rear view of the packaging bag 1 in Fig. 1 in a flattened state. [Figure 4] 2 is a perspective view of a bottom film 20a that constitutes the bottom portion 2 of the packaging bag 1. FIG. [Diagram 5] Figures 5A to 5C are explanatory diagrams of an aspect 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 AA in Figure 3A. Figure 5B is an enlarged view of region B in Figure 5A. Figure 5C shows a state in which the opening / closing member 23 in Figure 5B is open. [Figure 6] 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. [Figure 7] 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. [Figure 8]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 diagrams of the DD cross section 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 from the state shown in Figure 8A. Figure 8C shows the state of the packaging bag 1 after it has further expanded due to heating from the state shown in Figure 8B. [Figure 9] 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. [Figure 10] 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. [Figure 11] 11A to 11C are explanatory diagrams of a method for cooking a packaged food in which food is accommodated in a packaging bag 1 according to a second embodiment, and are schematic diagrams of the DD cross section in FIG. 6. FIG. 11A shows the state of the packaging bag 1 at the start of heating in the heating step of the cooking method. FIG. 11B shows the state of the packaging bag 1 from FIG. 11A after it has expanded due to heating. FIG. 11C shows the state of the packaging bag 1 from FIG. 11B after it has further expanded due to heating. [Figure 12] FIG. 11 is a perspective view of a packaging bag 1 according to a second embodiment of the present invention, showing the state after it has expanded due to heat and then opened at an opening portion 24. [Figure 13] 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. [Figure 14] 13 is a bottom view of a state in which a reinforcing member 27 shaped to fit the inner edge 2j of the lower end welded portion 13 is attached. [Figure 15]FIG. 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 16] Figure 16A is an oblique view showing the state in which disposable chopsticks 27a are 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 chopsticks 27a removed. [Figure 17] 13 is a perspective view showing an example of a method for fixing a reinforcing member 27 to a bottom surface portion 2 using a fixing means 29. FIG. [Figure 18] 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. [Figure 19] 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. [Figure 20] 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 a double-sided tape 29a. [Figure 21] FIG. 21A shows a process of fixing the lower end 20j of the peripheral wall film 20b to a plate-shaped member 42, and FIG. 21B shows a process of fixing the bottom film 20a to the back surface of the plate-shaped member 42 of FIG. 21A. [Figure 22] 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. [Figure 23] FIG. 2 is a plan view showing a state in which a doughnut-shaped steam release seal portion 11a is provided. [Figure 24]Fig. 24A is a perspective view showing a state in which overlapping portion 28 is formed on film 20c. Fig. 24B is a perspective view showing a state after first bottom surface portion 2a is formed on overlapping portion 28 from the state of Fig. 24A. [Diagram 25] 24C is a perspective view showing the state after second bottom surface portion 2b and side end welded portion 12 have been formed from the state shown in FIG. 24B. [Figure 26] FIG. 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 strip shape from the state shown in FIG. 26A. [Figure 27] FIG. 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. [Figure 28] 2 is a perspective view showing a state in which a reinforcing member 27 is arranged along a front edge 2c and a rear edge 2d of the bottom portion 2 so as to reinforce the bottom portion 2. FIG. [Figure 29] Figure 29A shows a state in which a reinforcing member 27 is placed along the leading edge 20a3 and trailing edge 20a4 of the bottom film 20a, and a cover film 20k is placed above it, and Figure 29B shows a state in which the bottom film 20a and the cover film 20k are overlapped to form a welded portion 20l around the reinforcing member 27. [Diagram 30] The figure shows a state in which an opening 13b communicating with the inside of the packaging bag 1 is provided in an unsealed portion 13a provided in a lower end welded portion 13 of the packaging bag 1. [Diagram 31] 3 shows a state in which the reinforcing member 27 is fixed only to the front edge 2c of the bottom portion 2. [Diagram 32] Fig. 32A is a schematic plan view of a step of attaching reinforcing member 27 to bottom surface portion 2. Figs. 32B to 32D are schematic cross-sectional views of a cross section perpendicular to the conveyance direction at first to third positions, respectively. [Diagram 33] Figure 33A shows a configuration in which reinforcing member 27 is fixed by fixing extensions 3a1, 4a1 of the front lower part 3a and the back lower part 4a to the bottom part 2 while surrounding reinforcing member 27 with extensions 3a1, 4a1, and Figure 33B is an enlarged view of area B in Figure 33A. [Diagram 34] Figure 34A shows a configuration in which overlapping portions 3a2, 4a2 are formed with extensions 3a1, 4a1 of the front lower portion 3a and the back lower portion 4a surrounding reinforcing member 27, and reinforcing member 27 is fixed by forming welding portions at overlapping portions 3a2, 4a2, and Figure 34B is an enlarged view of area B in Figure 34A. [Diagram 35] 1 is a perspective view showing a state in which the packaging bag 1 is fixed to a general-purpose member 30 by using a fixing means 29. FIG. [Diagram 36] Figure 36A is an oblique view of the outer packaging body 32b having first and second easy-to-tear portions 32b3, 32b4, Figure 36B shows the state after the outer packaging body 32b has been cut and opened along the first easy-to-tear portion 32b3 from Figure 36A, and Figure 36C shows a reinforcing member 27 formed into a triangular prism shape by folding the cut-out piece 32b5 obtained by cutting the outer packaging body 32b along the second easy-to-tear portion 32b4 from the state of Figure 36B. [Figure 37] Figure 37A is an oblique view of another form of outer packaging body 32b having first and second easy-to-tear portions 32b3, 32b4, Figure 37B shows the state after the outer packaging body 32b has been cut and opened along the first easy-to-tear portion 32b3 from Figure 37A, and Figure 37C shows a cut-out piece 32b5 obtained by cutting the outer packaging body 32b along the second easy-to-tear portion 32b4 from the state of Figure 37B. [Figure 38] Figure 38A is an oblique view of a packaging bag 1 with the bottom portion 2 facing upward and a reinforcing member 27 made of cut-out piece 32b5, and Figure 38B shows the state after the reinforcing member 27 has been fixed to the bottom portion 2 from the state shown in Figure 38A. [Figure 39] FIG. 39A is a plan view of the packaging bag 1 contained in the outer wrapping body 32c, and FIG. 39B is a cross-sectional view taken along line BB in FIG. 39A. [Diagram 40] Fig. 40A shows the state after the lid portion 32c5 is opened from the state of Fig. 39B. Fig. 40B shows the state in which the peripheral portion 21 rises from the state of Fig. 40A due to heating, and the front portion 3 abuts against the edge 32c2. Fig. 40C shows the state in which the peripheral portion 21 rises further from the state of Fig. 40B, and the front facing portion 3c abuts against the edge 32c2, suppressing the lifting of the front edge 2c. [Diagram 41] Figures 41A and 41B are perspective views of the holding jig 44. Figures 41A and 41B show the first support portion 44a in a held state and a released state, respectively. [Diagram 42] Figure 42A shows the state after a portion of the bottom portion 2 has been inserted into gap 44g from the state shown in Figure 41B, and Figure 42B shows the state after the bottom portion 2 has been further inserted from the state shown in Figure 42A and three sides of the bottom portion 2 are supported by the second to fourth support portions 44b to 44d. [Diagram 43] 42B, the first support portion 44a is put into a holding state, and the four sides of the bottom surface portion 2 are supported by the first to fourth support portions 44a to 44d. [Diagram 44] Fig. 44A is a perspective view showing a state after the holding jig 44 is attached to the adhesive application device 45. Fig. 44B shows a state after the transport platform 45c has been moved from the state of Fig. 44A to a first position. Fig. 44C shows a state after the transport platform 45c has been moved from the state of Fig. 44B to a second position. [Diagram 45] Fig. 45A shows the state after holding jig 44 has been removed from adhesive application device 45 from the state shown in Fig. 44C, and reinforcing member 27 has been placed on bottom portion 2 so as to overlap it. Fig. 45B shows the state after reinforcing member 27 has been pressed against bottom portion 2 by pressing portion 46 from the state shown in Fig. 45A. [Figure 46] FIG. 46A is a plan view of a state in which a packaging bag 1 is contained in an outer wrapping body 8 with a pattern 8j, and FIG. 46B is a cross-sectional view taken along line BB in FIG. 46A. [Figure 47] A sheet 8a for forming the outer wrapper 8 of FIG. 46 is shown. [Figure 48] Figure 48 shows the state in which the peripheral surface portion 21 rises up from the state shown in Figure 46 upon heating and pushes up the first and second upper surface portions 8e1, 8e2, Figure 48A is a cross-sectional view corresponding to Figure 46B, and Figure 48B is a right side view of Figure 48A. [Figure 49] 48A, showing a state in which peripheral portion 21 is further raised from the state in FIG. 48. FIG. [Figure 50]FIG. 50A is a perspective view of the vicinity of bottom portion 2 of packaging bag 1, and FIG. 50B is a bottom view of packaging bag 1 of FIG. 50A. [Figure 51] 51 is a schematic cross-sectional view of the packaging bag 1 of Fig. 50. The contents are not shown. [Figure 52] 52A and 52B correspond to FIGS. 50A and 50B, respectively, and show modified examples of bottom end welded portion 13. FIG. [Figure 53] 53A to 53C show a process of laying the peripheral portion 21 down on the rear edge 2d side after the packaging bag 1 is filled with the contents W. [Figure 54] FIG. 54A shows a packaging bag 1 in which a bottom end welded portion 13 having an angular intersection 13f is formed, and FIG. 54B shows a packaging bag 1 in which a bottom end welded portion 13 having a curved inner edge 13c2 is formed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Each feature described in the following embodiment can be combined with each other. Also, each feature can be an invention independently.

[0010] In the embodiments shown below, the invention of first to seventh aspects shown below is disclosed, and the claims relate to at least a part of them.

[0011] (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.

[0012] (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.

[0013] (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.

[0014] (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 placed on the ground and the peripheral portion inclined at an angle of 30° or less relative to a horizontal plane.

[0015] (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 front and back portions facing each other and rising from the bottom portion, the front and back portions being integrally configured to be 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.

[0016] (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.

[0017] (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.

[0018] 1. First embodiment 1.1. Structure of packaging bag 1 As shown in Fig. 1, a packaging bag 1 according to a first embodiment of the present invention is a packaging bag for use in a microwave oven, which is made of a flexible film 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.

[0019] As shown in Figures 1 to 3B, the packaging bag 1 has a bottom surface portion 2 and a peripheral surface portion 21. The bottom surface portion 2 is formed of a bottom film 20a shown in Figure 4, and is provided with a reinforcing member 27 as shown in Figure 1. The peripheral surface portion 21 is provided so as to rise from the bottom surface portion 2, and has a front surface portion 3 and a back surface portion 4 that face each other in the front-rear direction.

[0020] 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 be flat.

[0021] 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 part 3. Back view means that the packaging bag 1 in the same state is viewed in a direction perpendicular to the back part 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 part 3 (and the back part 4) rises from the bottom part 2 is the top side. Also, the left and right sides when the front part 3 is placed in front are the left and right sides of the packaging bag 1. Furthermore, the front part 3 side is the front side, and the back part 4 side is the back side. Also, in the following description, the top and bottom direction may be referred to as the height direction. As shown in FIG. 3A and FIG. 3B, the packaging bag 1 is formed to be linearly symmetrical with respect to a center line in the left-right direction.

[0022] 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 ensured inside the packaging bag 1, and in the case where the contents are food, the packaging bag 1 can stand on its own after heating and be used as tableware.

[0023] The front surface portion 3 includes a lower front surface portion 3a and an upper front surface portion 3b. The lower front surface portion 3a is welded to the bottom film 20a of the bottom surface portion 2. The lower front surface portion 3a and the upper front surface portion 3b are welded to each other at a seam portion 10 formed by overlapping the inner surfaces of these portions. By providing the seam portion 10, a large volume can be secured inside the packaging bag 1.

[0024] The peripheral surface portion 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 portion 3 and the back surface portion 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 portion 22 that opens upward is formed as shown in FIG. 2A by tearing the peripheral surface portion 21 along the left-right direction at the upper opening portion 26 and cutting off the upper end side portion of the peripheral surface portion 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.

[0025] In one example, the upper end welded portion 19 is not formed before the contents are filled into the packaging bag 1, and the contents are filled into the packaging bag 1 through the opening 22 shown in FIG. 2. In this case, the contents are likely to adhere to the inner surface of the packaging bag 1, and in particular, it is unhygienic for the contents to adhere to the opening / closing member 23. To solve this problem, in a modified example shown in FIG. 30, an opening 13b communicating with the inside of the packaging bag 1 is provided in the bottom surface portion 2 by providing an unwelded portion 13a in the lower end welded portion 13. In this case, the contents can be filled into the packaging bag 1 through the opening 13b, and the adhesion of the contents to the opening / closing member 23 is suppressed. After the contents are filled, the opening 13b is welded and sealed. In the case where the opening / closing member 23 is not present, the upper end welded portion 19 is formed before the contents are filled through the opening 13b, and the upper end of the packaging bag 1 is sealed. On the other hand, when the opening / closing member 23 is present, the upper end welded part 19 may be formed either before or after the filling of the contents through the opening 13b, and it is not necessary to form the upper end welded part 19. Furthermore, when the packaging bag 1 has a seam 10, the opening 13b is preferably provided on the seam 10 side. In other words, it is preferable to form the opening 13b by providing an unwelded part 13a between the front part 3 and the bottom part 2 where the seam 10 is provided.

[0026] The upper opening portion 26 includes a tear initiation portion 26a which is a starting point for tearing the peripheral portion 21, and a cut line 26b on which a line indicating a portion to be cut to open is printed. The packaging bag 1 may be opened by tearing the peripheral portion 21 starting from the tear initiation portion 26a, or by cutting the peripheral portion 21 along the cut line 26b using a cutting tool such as scissors. The tear initiation portion 26a is formed by, for example, a notch or a cut. Also, instead of the cut line 26b, 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 an end portion.

[0027] 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 that it is not necessary to open the upper end of the packaging bag 1.

[0028] The opening / closing member 23 is configured to be able to open and close the opening 22 in the packaging bag 1 in a state in which the upper end of the upper opening portion 26 is opened. FIGS. 5A to 5C are explanatory views of a mode in which the opening / closing member 23 opens and closes the opening 22 of the packaging bag 1, 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 FIG. 5B indicates the position of the lower end of the upper opening portion 26 in the up-down direction (in this embodiment, position J of the lower end of the tear start portion 26a shown in FIG. 3A). The opening / closing member 23 includes a front side engaging member 23a and a back side engaging member 23b that can be engaged with each other. A base 23a1 of the front side engaging member 23a and a 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 opening 22 is closed by engaging the hook portion 23a2 of the front side engaging member 23a with the hook portion 23b2 of the rear side engaging member 23b, and as shown in FIG. 5C, the opening 22 is opened by releasing the engagement.

[0029] The bases 23a1 and 23b1 may be welded to the front part 3 and the rear part 4 over their entire surfaces, respectively, but it is preferable that they are welded to the surfaces located above and below the hook parts 23a2 and 23b2. 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 part 4 at the surfaces located above and below the hook parts 23b2, and that the front side engaging member 23a welded to the front part 3 where the joining part 10 is provided is welded to the inner surface of the front part 3 at the surface above the hook parts 23a2, and that the surface below the hook parts 23a2 is not welded to the front part 3. In other words, it is more preferable to provide an unwelded portion with the front part 3 so as to extend from the lower end of the base 23a1 to the upper end of the hook parts 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, thereby preventing leakage of contents and escape of steam from the opening / closing member 23.

[0030] 5B, the vertical distance H5 between the upper end of the hook portion 23a2, 23b2 located at the upper side (in this embodiment, the upper end of the hook portion 23b2 of the back 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 or more and 20 mm or less, 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 or more and 7 mm or less, and preferably 1 mm or more, and can be, for example, 2 mm. By setting the distances H5 and H6 as described above, it is possible to secure a sufficiently large holding margin for putting a finger on the upper end of the packaging bag 1 when opening the opening 22 by the opening / closing member 23.

[0031] The tearing portion 24 is a portion for opening the packaging bag 1, and in this embodiment, the tearing portion 24 includes a tearing initiation portion 24a which is a starting point when tearing the peripheral portion 21, and a cut line 24b on which a line indicating a 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 tearing initiation portion 24a, or by cutting the peripheral portion 21 along the cut line 24b using a cutting tool such as scissors. The tearing initiation portion 24a is formed by, for example, 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 an end portion.

[0032] 1 and 2A, the packaging bag 1 has an upper cutout portion 5 and a lower main body portion 6 in the up-down 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.

[0033] 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.

[0034] The opening portion 24 is provided at a position closer to the bottom portion 2 than the joining portion 10. In other words, the joining portion 10 is provided at the cutout portion 5. Therefore, when the cutout portion 5 is removed during opening, the joining portion 10 is also removed. Therefore, the joining portion 10 does not get in the way when eating the contents.

[0035] As shown in Fig. 3A, a steam release seal portion 11 is formed on the peripheral surface 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 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.

[0036] 3A and 3B, a side end weld 12 is provided at the side end of the packaging bag 1 to weld the front portion 3 and the back portion 4 together. This allows the front portion 3 and the back portion 4 to be fixed in the front-to-rear direction. Furthermore, a bottom end weld 13 is provided at the bottom end of the packaging bag 1 to weld the bottom portion 2 and the front portion 3, and the bottom portion 2 and the back portion 4 together. The bottom end weld 13 welds the bottom portion 2 and the front portion 3, and the bottom portion 2 and the back portion 4 together at the side end and bottom end of the packaging bag 1 (areas surrounded by dashed lines in FIG. 3A).

[0037] As shown in FIG. 3A, the lower end welded portion 13 has a pair of sloped portions 13c and a central portion 13d. The sloped portions 13c are welded at an incline (diagonally) from the side ends of the packaging bag 1 toward the lower end of the central portion. The central portion 13d is provided between the pair of sloped portions 13c and is formed in a straight line. By providing the central portion 13d in a straight line, the main body portion 6 can be easily used as tableware. An air pocket 14 is provided on the outside of the sloped portions 13c. The air pocket 14 is formed in a triangular shape, and is a space in which air that could not be completely discharged to the outside by welding at the lower end welded portion 13 remains. By providing the air pocket 14, the remaining air in the lower end welded portion 13 is collected in the air pocket 14, improving the strength of the weld.

[0038] As shown in Figures 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 Figure 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 lower surface 20a2 of the bottom film 20a (the surface facing the outside of the packaging bag 1, of the two opposing surfaces of the bottom film 20a), as shown in Figures 1 and 3B.

[0039] 1 and 3, in a state where 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 FIG. 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.

[0040] The reinforcing member 27 preferably has a higher rigidity than the bottom film 20a. In the present disclosure, rigidity refers to the difficulty of bending a member when a force is applied to bend the member, and can be expressed by, for example, an index such as bending rigidity, elastic modulus (flexural elastic modulus, Young's modulus), and bending strength. By providing the reinforcing member 27 having 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 curving in the front-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.

[0041] Furthermore, the reinforcing member 27 of this embodiment has flexibility to the extent that it allows bending such as curvature or bending in the left-right direction (longitudinal direction) of the bottom film 20a as the packaging bag 1 expands and the front portion 3 and the back portion 4 move away from each other in the front-rear direction. By bending the bottom film 20a in the left-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.

[0042] The material of the reinforcing member 27 may be any material that can realize a high degree of rigidity that can suppress 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, if the reinforcing member 27 is made of cardboard or foam, the packaging bag 1 can be easily placed 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, or 5 (unit: mm), or may be within a range between any two of the values ​​exemplified here, for example, 0.68 mm. The basis weight of the paper constituting the reinforcing member 27 is, for example, 200 g / m 2 More than 900g / m 2 Less than or equal to 250 g / m 2 More than 800g / m 2 Less than 300 g / m is preferable. 2 More preferably, the basis weight is 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900 (unit: g / m 2 ), or may be within a range between any two of the values ​​exemplified herein, for example 415 g / m2 It can be said that:

[0043] In addition, the reinforcing member 27 may be processed to suppress the curvature of the bottom film 20a in the front-rear direction while allowing bending in the left-right direction. For example, when the reinforcing member 27 is made of paper, it may be processed to form folds 27b near both left-right edges so that the bottom film 20a can be easily folded in a mountain fold along the front-rear direction, so that the bottom film 20a can be bent in the left-right direction as the packaging bag 1 expands. It is preferable that the folds 27b are offset from the start point 13c1 of the gradient portion 13c on the central portion 13d side by 0 to 3 cm in the left-right direction. Specifically, this offset may be, for example, 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0 cm, or may be in a range between any two of the values ​​exemplified here. Furthermore, if the vertical distance between inner edge 13e of bottom end welded portion 13 and fold 31 is H7, then fold 27b is preferably provided at a position α×H7 from inner edge 12a of side end welded portion 12. α is, for example, 0.7 to 1.3, and specifically, for example, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, or 1.3, and may be within a range between any two of the numerical values ​​exemplified here.

[0044] The reinforcing member 27 may be attached to the bottom film 20a with an adhesive. Alternatively, when plastic or paper coated with a resin film on the attachment surface is used as the reinforcing member 27, the reinforcing member 27 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. From the viewpoint of rigidity, it is preferable that the reinforcing member 27 or the bottom film 20a is attached to the bottom film 20a over the entire surface or the entire periphery. On the other hand, the reinforcing member 27 may be locally attached to the bottom film 20a at the four corners of the reinforcing member 27 or the bottom film 20a, as shown by the attachment parts 27c illustrated in FIG. 3B. This form is preferable from the viewpoints of productivity and material cost, and is also preferable from the viewpoint that heat from the packaging bag 1 is less likely to be transferred to the reinforcing member 27.

[0045] 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 disposed on the bottom portion 2 without being attached.

[0046] The reinforcing member 27 may be provided so as to cover the entire lower surface 20a2 or the upper surface 20a1 of the bottom film 20a, or may be provided so as to cover a part of it. From the viewpoint of effectively suppressing the curvature of the bottom film 20a, the reinforcing member 27 is preferably provided at least near both ends of the bottom portion 2 in the left-right direction of the packaging bag 1, and more preferably provided at least along the left and right edges of the bottom portion 2.

[0047] Furthermore, the reinforcing member 27 is preferably arranged to cover 20% or more of the area of ​​the lower surface 20a2 or upper surface 20a1 of the bottom film 20a, and more preferably to cover 40% or more, and more specifically 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.

[0048] In the packaging bag 1 shown in Fig. 3A, the vertical length H1 of the cut-out 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 6 is, for example, 4 to 20 cm, 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 6 when adding cooking liquid during cooking of 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.

[0049] Moreover, the length H2 is preferably longer than the length H3 (see Figs. 3A and 4) from the center line E1 to the lower 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, 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 when the packaging bag 1 is opened becomes low, limiting the amount of the contents.

[0050] The length H3 is preferably 3 to 6 cm, and more specifically, may be any value of 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 the main body 6 is also used as tableware, it is preferable that the main body 6 is of this size.

[0051] The front portion 3 and the 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 the 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 on the lower and upper sides, respectively, of the fold 41, approach each other.

[0052] In one example, the front surface portion 3 is provided with a steam release seal portion 11 (shown in FIG. 3), the bottom surface portion 2 is unfoldable, and as shown in FIGS. 6 and 8, the peripheral surface portion 21 is in a state where the bottom surface portion 2 and the back surface portion 4 are in a valley fold and laid down relative to the bottom surface portion 2 when the bottom surface portion 2 is unfolded (i.e., inclined so that the inclination angle with respect to the bottom surface portion 2 is 30° or less). With this configuration, when the packaging bag 1 is placed in the microwave oven so that the bottom surface portion 2 is in contact with the ground, the steam release seal portion 11 provided on the front surface portion 3 is necessarily placed on the upper side of the packaging bag 1, so that 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° 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, this inclination angle may be any of the values ​​0, 5, 10, 15, 20, 25, and 30 (unit: degrees), for example, and may be within a range between any two of the numerical values ​​exemplified here.

[0053] 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, and therefore 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 portion of the lower end welded portion 13 that is provided at the lower end of the packaging bag 1 (in other words, the lower end of the unwelded portion of the inner surface of the front portion 3), as shown in FIG. 7A.

[0054] In Fig. 7A, E4 indicates the center line of the sealed space S in the up-down 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 value of 1.1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, or 10, or may be within a range between any two of the numerical values ​​exemplified here.

[0055] Furthermore, 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 one of the values ​​1.1, 1.5, 2, 3, 4, 5, 6, 7, and 8, and may be within a range between any two of the numerical values ​​exemplified here.

[0056] 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, it is possible to effectively prevent the bottom portion 2 from curving away from the grounded surface as the packaging bag 1 expands when heating is performed in a microwave oven with the bottom portion 2 grounded and the peripheral portion 21 inclined, as described below.

[0057] 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.

[0058] 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, the bottom film 20a and the peripheral wall film 20b may be films having the same structure and physical properties, or films having different structures and physical properties.

[0059] The base layer is disposed so as to be exposed on the outer surface of the packaging bag 1, and the sealant layer is disposed so as to be exposed on the inner surface of the packaging bag 1. The sealant layers are welded (heat sealed) to each other to form a welded portion.

[0060] 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. The substrate layer may include a paper layer, may be composed of only a paper layer, or may be composed of a paper layer and the above-mentioned resin layer laminated together. As a film constituting the substrate layer, one having linear cut properties 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 (such as silver ions). 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, and it is hygienic when removed from the microwave oven.

[0061] The adhesive layer is a layer for bonding the base layer and the sealant layer so as to be laminated 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 acid 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.

[0062] The sealant layer can be formed of a resin having excellent weldability. The sealant layer can be formed of a polyolefin resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, or ethylene-propylene block copolymer, and more specifically, non-oriented polypropylene or linear low-density polyethylene can be used. The film constituting the sealant layer is preferably one having linear cutability in the MD direction.

[0063] It is preferable to use a film in which a first base material layer and a second base material layer, and a sealant, etc., 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 a 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 the opening portion 24 uses a peripheral wall film 20b with linear cutting properties, the opening portion 24 is prone to problems such as being easily torn straight due to heating in a microwave oven. By applying the easy-tear treatment as described above, such problems can be eliminated even after heating in a microwave oven.

[0064] The easy-tear processing is, for example, perforation processing. When perforation processing is performed, perforations are formed by cutting into the entire second base material layer and a 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. In addition, multiple rows of perforations may be formed along the extension direction.

[0065] From the viewpoint of a size that can be placed on a turntable of a microwave oven, the length H4 in the left-right direction at the bottom end of the packaging bag 1 shown in Fig. 3A is preferably 10 to 25 cm, and more preferably 18 cm or more. More specifically, the length H4 is, for example, any of the values ​​10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25 (unit: cm), and may be within a range between any two of the values ​​exemplified here, for example, 20 cm.

[0066] 1.2.How to prepare packaged foods Next, a cooking method for a 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 puts 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 the food is placed in the packaging bag 1 at the factory. In this case, the opening and closing member 23 can be omitted.

[0067] 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 DD cross section in Figure 6 (a cross section passing through the center in the left-right direction of the packaging bag 1 and parallel to the front-rear direction).

[0068] 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 as to come 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 as to come into contact with the instant noodles. In this embodiment, the opening / 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 / 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.

[0069] 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 part 2 is grounded in the microwave oven and the peripheral part 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 part 2 is grounded on a substantially horizontal surface G such as a turntable in the microwave oven. Microwave ovens are generally designed so that microwaves are concentrated in the lower center of the interior, and by starting heating with the peripheral part 21 laid down, it is possible to efficiently heat the food in the packaging bag 1.

[0070] The inclination angle θ refers to the smaller angle between the peripheral portion 21 and the horizontal plane. In addition, when the front portion 3 and the back portion 4 constituting the peripheral portion 21 are separated due to the presence of contents in a state in which the peripheral portion 21 is inclined, 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).

[0071] The inclination angle θ is, for example, 0° to 30°, preferably 0° to 20°, and more preferably 0° to 10°. More specifically, the inclination angle θ may be 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 values ​​exemplified here.

[0072] The peripheral surface portion 21 may be inclined toward either the front side or the rear side of the packaging bag 1, but is preferably inclined toward the side of the front surface portion 3 or the rear surface portion 4 on which the steam release seal portion 11 is not provided (the rear surface 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.

[0073] In this embodiment, the front surface portion 3 and the back surface portion 4 are integrally inclined rearward relative to the bottom surface portion 2. By inclining the peripheral surface 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 having a relatively flat shape such as instant noodles, a wider area can be brought into contact with the cooking liquid compared to when the peripheral surface portion 21 is not inclined.

[0074] When heating is started, the packaging bag 1 expands with an increase in the internal pressure of the packaging bag 1, 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, so that a force is applied 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-rear direction, and the bottom portion 2 is maintained in a state of being grounded on the surface G during the heating process. In addition, the peripheral portion 21 rises with the expansion of the packaging bag 1, 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-rear direction.

[0075] Furthermore, 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 curves the front end side of the bottom portion 2 upward. In this embodiment, in addition to the curvature of the bottom film 20a being suppressed by the reinforcing member 27, 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. Furthermore, 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 curvature of the bottom portion 2 as described above.

[0076] 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 such left-right bending of the bottom film 20a, so the left and right directions of the bottom film 20a are bent, and the fold 31 of the front portion 3 and the fold 41 of the back portion 4 are unfolded 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 with respect 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 is changed, thereby improving the uniformity of heating.

[0077] After the heating is completed, the packaging bag 1 preferably stands on its own with the bottom part 2 facing downward. In this case, after the heating is completed, the packaging bag 1 can be easily removed from the microwave oven in the standing state. Moreover, by opening the standing packaging bag 1 at the opening part 24, the food inside can be eaten using the packaging bag 1 as a dish.

[0078] As described above, when the packaging bag 1 expands, the portion of the front portion 3 on the bottom portion 2 side expands, and a force is applied to bend the front end side of the bottom portion 2 upward. On the other hand, little or no force is applied to the rear end side of the bottom portion 2 to bend it upward. For this reason, as shown in FIG. 31, the reinforcing member 27 may be fixed to the bottom portion 2 only on the front edge 2c side of the bottom portion 2 by a fixing means 29 provided along the front edge 2c of the bottom portion 2, and the rear edge 2d side may be left unfixed. Of the pair of edges in the front-rear direction of the bottom portion 2, the one that is below the back portion 4 when the peripheral portion 21 is laid down before heating is the rear edge 2d, and the other edge is the front edge 2c.

[0079] 1.3. Manufacturing method of packaging bags Next, a method for manufacturing 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 an unfolded state.

[0080] 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.

[0081] 9A to 9B, one end C1 of the ring C is cut, and the bottom film 20a folded in a V shape at the center line E1 is inserted. Then, as shown in Figs. 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, thereby forming the bottom portion 2, the front portion 3, and the back portion 4.

[0082] 10B, an opening / closing member 23 is inserted between the front portion 3 and the back portion 4 near the other end C2 of the ring C (near the upper ends of 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 to produce the packaging bag 1. 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.

[0083] In the reinforcing member attachment step, a reinforcing member 27 is provided on the bottom surface 2 of the completed 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 thereof by adhesive or welding. This step can be performed using a conveyor 43 having a gap 43b between a pair of conveying parts 43a, as shown in FIG. 32. Specifically, first, in the first position shown in FIGS. 32A and 32B, the packaging bag 1 is placed on the conveyor 43 so that the bottom surface 2 faces upward, the peripheral surface part 21 is placed in the gap 43b, and the front lower part 3a and the back lower part 4a of the front surface part 3 and the back surface part 4 that face the bottom surface part 2 face the conveying part 43a. The conveyor 43 conveys the packaging bag 1 toward the right side of FIG. 32A. In the second position shown in FIGS. 32A and 32C, the reinforcing member 27 is attached to the bottom surface part 2 of the packaging bag 1. 32A and 32D, the packaging bag 1 with the reinforcing member 27 attached thereto is transported by conveyor 43 to a third position downstream of the second position. When reinforcing member 27 is provided on the upper surface 20a1 side of bottom film 20a, reinforcing member 27 may be attached by adhesive or welding to bottom film 20a of packaging bag 1 after bag production and before the contents are filled therein, or reinforcing member 27 may be inserted into packaging bag 1 without being attached and disposed on bottom portion 2.

[0084] The reinforcing member attachment step is preferably performed after the bag making step. It is possible to attach the reinforcing member 27 to the bottom film 20a before the bag making step, and then perform the bag making step. However, in that case, the bag making step may become difficult to perform, so the reinforcing member attachment step is preferably performed after the bag making step. 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 preferably in a lying state. In this case, the reinforcing member 27 is easily attached.

[0085] Furthermore, when the process includes a content filling step of filling and sealing the contents in the packaging bag 1, the reinforcing member attachment step may be performed before or after the content filling step. If performed before the content filling step, there is an advantage that the reinforcing member 27 is easily attached. 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.

[0086] 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 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.

[0087] 11A to 11C are explanatory diagrams of a method for cooking a packaged food in which food is accommodated in a packaging bag 1 according to the second embodiment. When the packaging bag 1 expands due to heating from the state shown in Fig. 11A, the reinforcing member 27 suppresses bending of the bottom film 20a in the front-rear direction, as in the first embodiment. When the packaging bag 1 further expands and 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, a force is applied to the bottom film 20a to bend both left and right edges upward.

[0088] At this time, in this embodiment, the reinforcing member 27 suppresses the bending of the bottom film 20a in the left-right direction, 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 a state inclined backward. Then, when the 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.

[0089] 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 lower surface of the bottom portion 2 to be placed on the ground and the packaging bag 1 to stand on its own. When the packaging bag 1 is used 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 the stability of the bag in a self-supporting state.

[0090] 3. Third embodiment The shape and arrangement of the reinforcing member 27 are not limited to the examples of the above-mentioned embodiment. Modifications of the reinforcing member 27 will now be described.

[0091] The shape of the reinforcing member 27 is arbitrary, and can be, for example, a plate, a film, a rod, a tube, or the like. 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. Furthermore, the reinforcing member 27 may 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.

[0092] 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 formed of a plurality of members. For example, as shown in FIG. 13B, the reinforcing member 27 may be formed of two long plate-shaped members arranged along the left and right edges of the bottom portion 2, respectively, 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, respectively. 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, the reinforcing member 27 is preferably 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, and the self-supporting ability of the packaging bag 1 is likely to be improved.

[0093] 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 the food in the packaging bag 1 is cooked, 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. Openings 2f may be provided in protruding pieces 2e provided on the front edge 2c and the rear edge 2d of the bottom portion 2, and the disposable chopsticks 27a may be inserted into the pair of openings 2f to be disposed on the bottom portion 2. In this case, the disposable chopsticks 27a are detachable from the bottom portion 2. 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 the 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 welded portion 13 as shown in FIG. 16.

[0094] The method of holding the disposable chopsticks 27a shown here can also be applied to reinforcing members 27 other than the disposable chopsticks 27a. Figure 36A shows a box-shaped outer packaging body 32b that houses the packaging bag 1. The outer packaging body 32b is provided with first and second easy-to-tear parts 32b3 and 32b4 formed by perforations or the like. The outer packaging body 32b is cut along the first easy-to-tear part 32b3 to open the outer packaging body 32b as shown in Figure 36B, and then the outer packaging body 32b is cut along the second easy-to-tear part 32b4 to partially cut out the outer packaging body 32b. The cut-out piece 32b5 is folded along the folding line 32b6 shown by the dotted line, for example, into a triangular prism shape as shown in Figure 36C, to create an elongated reinforcing member 27. The reinforcing member 27 created in this way can be inserted through the opening 2f and placed on the bottom part 2, as shown in Figures 15 and 16, in the same way as the disposable chopsticks 27a.

[0095] Also, the outer packaging body 32b may be provided with first and second easy-to-tear portions 32b3 and 32b4 as shown in FIG. 37A. In this case, the outer packaging body 32b is cut along the first easy-to-tear portion 32b3, and the outer packaging body 32b is opened as shown in FIG. 37B. Then, the outer packaging body 32b is cut along the second easy-to-tear portion 32b4, and the outer packaging body 32b is partially cut away to form a cut-away piece 32b5 as shown in FIG. 37C. The cut-away piece 32b5 can be used as the reinforcing member 27 as it is, and can be fixed to the bottom portion 2 of the packaging bag 1 as shown in FIG. 38A to FIG. 38B. It is preferable to provide a fixing means such as double-sided tape on either the bottom portion 2 or the cut-away piece 32b5 (preferably the one having the smaller area). In this case, the user can easily attach the reinforcing member 27 to the bottom portion 2.

[0096] Also, as shown in FIG. 28, a reinforcing member 27 may be attached so as to reinforce the bottom portion 2 along the front edge 2c and the rear edge 2d of the bottom portion 2. In this case, the reinforcing member 27 may be a columnar member such as a straw. The reinforcing member 27 can be attached so as to reinforce the bottom portion 2 along the front edge 2c and the rear edge 2d by providing a pocket 2k extending along the front edge 2c and the rear edge 2d in the lower end welded portion 13 and inserting the reinforcing member 27 into the pocket 2k after the packaging bag 1 is manufactured. When the packaging bag 1 tries to rise up as shown in FIG. 8 during heating, the bottom portion 2 is likely to bend so that both ends in the left and right direction of the bottom portion 2 are pushed up as shown in FIG. 2B. If the bottom portion 2 is excessively curved, the contact with the bottom portion 2 becomes unstable and the packaging bag 1 is difficult to rise up. On the other hand, if the front edge 2c and the rear edge 2d of the bottom portion 2 are reinforced as shown in FIG. 28, the bending of both ends in the left and right direction of the bottom portion 2 is suppressed, so that the packaging bag 1 is easy to rise up.

[0097] 33, the reinforcing member 27 may be fixed to the bottom surface portion 2 in a state where the reinforcing member 27 is surrounded by the extensions 3a1, 4a1 that extend the front lower portion 3a and the back lower portion 4a below the fold 31 of the front surface portion 3 and the back surface portion 4 beyond the bottom surface portion 2. Furthermore, the reinforcing member 27 may be fixed to the bottom surface portion 2 in a state where the reinforcing member 27 is surrounded by the extensions 3a1, 4a1, by forming overlapping portions 3a2, 4a2 on the extensions 3a1, 4a1, respectively, and forming welding portions on the overlapping portions 3a2, 4a2, as shown in FIG. Since the sealant layers of the films face each other at the overlapping portions 3a2, 4a2, it is easy to form welding portions.

[0098] The reinforcing member 27 that reinforces the bottom portion 2 along the leading edge 2c and the trailing edge 2d may be attached to the bottom film 20a as shown in FIG. 29B. In this case, the packaging bag 1 is manufactured using the bottom film 20a to which the reinforcing member 27 is attached, thereby obtaining a packaging bag 1 in which the bottom portion 2 is reinforced by the reinforcing member 27 along the leading edge 2c and the trailing edge 2d. As a method for attaching the reinforcing member 27 to the bottom film 20a, as shown in FIG. 29A, the reinforcing member 27 is disposed along each of the leading edge 20a3 and the trailing edge 20a4 of the bottom film 20a, and the bottom film 20a and the cover film 20k are overlapped, and a welding portion 20l is formed around the reinforcing member 27 as shown in FIG. 29B. Although the cover film 20k is strip-shaped in FIG. 29A, the cover film 20k may have any shape that allows the reinforcing member 27 to be fixed to the bottom film 20a.

[0099] 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, etc. In one example, the reinforcing member 27 can be attached to the bottom surface portion 2 using fixing means 29 such as adhesive tape, adhesive, clips, etc., as shown in FIG. 17.

[0100] 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 to the bottom film 20a at the welding parts 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.

[0101] The reinforcing member 27 may be attached to the bottom portion 2 in advance at a 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 select 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 packed together using an outer packaging body 32 as shown in Figs. 26 to 27.

[0102] In one example, retort food or frozen food in which food is sealed in the packaging bag 1 may be cooked by boiling water other than in 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 by boiling water if the reinforcing member 27 is previously attached to the bottom portion 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 portion 2, cooking by boiling water can be performed even if the reinforcing member 27 is made of a material that is not water resistant by selecting not to attach the reinforcing member 27 to the bottom portion 2. From another perspective, if the reinforcing member 27 is previously attached to the bottom portion 2, it is necessary to form the reinforcing member 27 from a material that is water resistant in order to enable cooking by boiling water. 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.

[0103] In addition, the reinforcing member 27 is preferably 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 (for example, one configured like 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.

[0104] 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 from the side where the peripheral surface portion 21 is inclined. In this case, since the reinforcing member 27 overlaps with 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 after a food is placed in it, 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. However, by having the reinforcing member 27 protrude from the bottom surface portion 2, the portion 2g can withstand this downward torque more easily, and the peripheral surface portion 21 tends to stand upright when heated. Furthermore, since the protruding portion does not heat up easily even after the contents are heated, the packaging bag 1 can be easily pulled out of the microwave oven by grasping the protruding portion.

[0105] 20, fixing means 29 (e.g., adhesive means such as double-sided tape 29a) may be provided on bottom portion 2, and bottom portion 2 may be fixed to a general-purpose member 30 (a member not prepared as reinforcing member 27) using fixing means 29, and this general-purpose member 30 may be used as reinforcing member 27. Examples of general-purpose member 30 include tableware such as dish 30a, plates placed inside the microwave oven, and the floor surface of the oven. Fixing means 29 may be provided, for example, in a portion including the center of bottom portion 2 in the left-right direction.

[0106] Furthermore, as shown in FIG. 35, the fixing means 29 may be provided so as to straddle the front facing portion 3c of the front portion 3 facing the bottom portion 2 and the general-purpose member 30. The fixing means 29 is preferably a means capable of fixing the front edge 2c of the bottom portion 2 to the general-purpose member 30 by attaching it to both the front facing portion 3c and the general-purpose member 30, such as an adhesive tape 29b. The fixing means 29 is preferably attached to a portion including the center in the left-right direction of the front facing portion 3c, for example. When the packaging bag 1 expands, the portion of the front portion 3 on the bottom portion 2 side expands, which causes the front edge 2c of the bottom portion 2 to rise up and tends to inhibit the rising of the peripheral portion 21. However, by fixing the front facing portion 3c to the general-purpose member 30 with the fixing means 29, the rising of the front edge 2c can be suppressed and the rising of the peripheral portion 21 can be promoted. The adhesive tape 29b is preferably a reattachable tape. In this case, for example, if an adhesive tape 29b is attached to the packaging bag 1, the user can peel off the adhesive tape 29b from the packaging bag 1 and use it as the fixing means 29. Also, a locking member may be abutted against the front facing portion 3c to suppress lifting of the front edge 2c. The locking member need only be capable of abutting against the front facing portion 3c to suppress lifting of the front edge 2c, and does not need to be fixed to the front facing portion 3c. As will be described later, the outer wrapping body 32c shown in Figs. 39 to 40 is configured to suppress lifting of the front edge 2c by abutting the edge 32c2 of the opening 32c1 against the front facing portion 3c, thereby promoting the rising of the peripheral portion 21. Therefore, the outer wrapping body 32c functions as a locking member.

[0107] 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 surface portion 2, but in a viewpoint where the reinforcing member 27 is not essential, the reinforcing member 27 can be omitted.

[0108] 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, the lower end parts 20j of the two films facing each other at the cut part are folded outward by 90 degrees by a length H3 as shown in FIG. 21A. Then, the inner surfaces of the two films are both facing downward by folding, 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. 9B, the plate-like member 42 may be folded in half and inserted between two opposing films of the peripheral wall film 20b, and the plate-like member 42 may be welded to the peripheral wall film 20b to produce a packaging bag 1 in which the plate-like member 42 is fixed to the front part 3 and the back part 4. The plate-like member 42 is preferably made of resin. The plate-like member 42 can be fixed to the film by welding.

[0109] It is preferable that plate-like member 42 has a rigidity sufficient to allow peripheral portion 21 to stand up when packaging bag 1 containing the contents is started to be heated in a microwave oven with peripheral portion 21 of packaging bag 1 lying down as shown in Fig. 8A, and packaging bag 1 expands with an increase in internal pressure of packaging bag 1 due to heating in a microwave oven as shown in Figs. 8B and 8C. This makes it possible to allow peripheral portion 21 to stand up during heating without separately providing reinforcing member 27. If plate-like member 42 does not easily bend in the front-rear direction, the force generated when packaging bag 1 expands tends to act in a direction that causes peripheral portion 21 to stand up, so it is particularly preferable that plate-like member 42 does not easily bend in the front-rear direction.

[0110] The thickness of the plate-like member 42 is, for example, 0.3 to 5 mm, preferably 0.5 to 3 mm, and more preferably 0.7 to 2 mm. Specifically, the thickness may be, for example, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0 mm, or may be within a range between any two of the numerical values ​​exemplified here.

[0111] Examples of the layer configuration of the plate-like member 42 include (a) a single-layer configuration of resin, (b) a laminated configuration having a sealant layer and a resin layer, and (c) a laminated configuration having a sealant layer and a paper layer. In the cases of (b) and (c), a laminated configuration further including a barrier layer may be used. The configurations (a) to (c) will be described in detail below.

[0112] (a) Single layer of resin In one example, the plate-like member 42 may have a single layer structure of resin. This resin is preferably a resin with excellent weldability, and is preferably a polyolefin resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, or ethylene-propylene block copolymer, and more preferably unstretched polypropylene or linear low-density polyethylene.

[0113] (b) Laminated structure having a sealant layer and a resin layer In one example, the plate-like member 42 may have a laminated structure having a sealant layer and a resin layer. The sealant layer may be made of a resin having excellent weldability, and the provision of the sealant layer allows the plate-like member 42 to be easily welded to the front part 3 and the back part 4. Examples of resins constituting the sealant layer include polyolefin resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, and ethylene-propylene block copolymer, and more specifically, non-oriented polypropylene and linear low-density polyethylene. The resin layer is a layer made of a resin other than the sealant layer, and may be made of, for example, a resin having excellent strength and high impact resistance. Examples of resins constituting the resin layer include polyamide, polyolefin, polyethylene, polyester, and the like.

[0114] The laminated structure having the sealant layer and the resin layer can be formed by extrusion lamination or dry lamination of the film constituting the sealant layer and the film constituting the resin layer. Such a laminated structure may also be formed by coating the resin constituting the sealant layer on the film constituting the resin layer.

[0115] The thickness of the sealant layer is, for example, 10 to 100 μm, specifically, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 μm, and may be in a range between any two of the numerical values ​​exemplified here.

[0116] (c) Laminated structure with a sealant layer and a paper layer In one example, the plate-like member 42 may have a laminated structure having a sealant layer and a paper layer. The explanation of the sealant layer is the same as that of "(b) Laminated structure having a sealant layer and a resin layer." The basis weight of the paper layer is, for example, 50 g / m 2 More than 80g / m is preferable. 2 More preferably, the basis weight of the paper layer is, for example, 300 g / m 2 Less than or equal to 300 g / m 2 Less than 250 g / m is preferable. 2More preferably, 200 g / m 2 More preferably, the basis weight is, for example, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 350, 400, 450, 500 g / m 2 and may be in a range between any two of the numerical values ​​exemplified herein or any value equal to or greater than the range.

[0117] The paper layer has a Taber stiffness (bending moment) of, for example, 2 mN·m or more, and preferably 4 mN·m or more. In this case, the rigidity of the plate-like member 42 increases, and the peripheral surface portion 21 is more likely to rise when heated in a microwave oven. The Taber stiffness is, for example, 2 to 20 mN·m, specifically, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 mN·m, and may be in a range between any two of the numerical values ​​exemplified here, or any one of them or more.

[0118] The laminated structure having the sealant layer and the paper layer can be formed by extrusion lamination or dry lamination of the film constituting the sealant layer and the paper constituting the paper layer. Such a laminated structure may also be formed by coating the resin constituting the sealant layer on the paper constituting the paper layer.

[0119] 21B, the bottom film 20a may be fixed to the back surface side of the plate-shaped member 42. In this case, the plate-shaped member 42 functions as a reinforcing member that suppresses bending of the bottom film 20a.

[0120] 5. Fifth embodiment In the fifth embodiment, a modified example of the steam release seal portion 11 will be described.

[0121] 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 seam portion 10, but it is not essential to provide the seam 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 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 / closing member 23 is left open, or the packaging bag 1 does not have the opening / 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 approximately V-shaped tapering toward the inside of the packaging bag 1, as in the first embodiment, or may be another shape.

[0122] Furthermore, the steam release seal portion 11 may be provided at a position 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 is at least partially peeled off to form a steam flow path, and steam is discharged to the outside through the ventilation portion 11c.

[0123] Also, an opening configured to allow steam to be discharged without leaking the contents may be provided in the packaging bag 1 without providing the steam release seal portion 11. Such an opening may be formed, for example, by slightly tearing the peripheral portion 21 before the start of heating.

[0124] 6. Sixth embodiment In the sixth embodiment, a modified example of the cooking method for prepackaged food will be described.

[0125] In the above embodiment, the case where the peripheral portion 21 stands upright when heating is completed has been described, but from the viewpoint of not requiring the peripheral portion 21 to stand upright among various aspects constituting the present invention, the peripheral portion 21 does not have to stand upright when heating is completed, but it is preferable that the bottom portion 2 is unfoldable. When the bottom portion 2 is unfoldable, heating is performed with the bottom portion 2 unfolded and in contact with the ground, which makes it easier for the food contents to move within the packaging bag 1 and reduces uneven heating. Furthermore, after heating is completed, 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.

[0126] Furthermore, from the viewpoint of various aspects constituting the present invention, in the viewpoint that it is not essential to ground the bottom surface portion 2 at the start of heating, the bottom surface portion 2 does not have to be grounded at the start of heating, but it is preferable that the peripheral surface portion 21 stands upright at the end of heating. Even in this case, the peripheral surface portion 21 is displaced during heating, which tends to reduce uneven heating of the food contents.

[0127] 7. Seventh embodiment In the seventh embodiment, a modified example of the method for producing the packaging bag 1 will be described.

[0128] In the first embodiment, the packaging bag 1 is manufactured using the bottom film 20a and the peripheral wall film 20b, but in the method of the present embodiment, the packaging bag 1 can be manufactured using a single film 20c.

[0129] First, as shown in FIG. 24A, the inner faces of the ends of a single film 20c are overlapped to form an overlapped portion 28, and as shown in FIG. 24B, the inner faces of the overlapped portion 28 are welded to form a first bottom portion 2a, and the remaining portion forms a ring D.

[0130] 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 welded 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.

[0131] The packaging bag 1 is obtained by the above steps. When 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. Note that the first bottom surface portion 2a and the second bottom surface portion 2b may be formed simultaneously, and then the side end welded portion 12 may be formed.

[0132] 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 that 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 that the work of unfolding the bottom portion 2 is not required. In addition, in the method of this embodiment, the packaging bag 1 can be produced using a single film 20c, so that the production equipment can be simplified compared to the method of the first embodiment.

[0133] 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, the steam release seal portion 11 is preferably provided in a portion other than the joint portion 10 as described in the fifth embodiment.

[0134] 8. Eighth embodiment In the eighth embodiment, an outer wrapping body and its modified examples will be described.

[0135] 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 housed 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 a heat 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 housed in the packaging bag 1 may be heated with the outer packaging body removed, or the food housed in the packaging bag 1 together with the outer packaging body may be heated.

[0136] 26 to 27, an outer packaging body 32 that covers the packaging bag 1 in which the food is enclosed can be used as the reinforcing member 27. Examples of the outer packaging body 32 include a cylindrical outer packaging body 32a as shown in Fig. 26A and a box-shaped outer packaging body 32b as shown in Fig. 27A.

[0137] The cylindrical outer wrapping 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 ends 32a3 in the left-right direction to form a cylindrical shape. The outer wrapping body 32a is cut, for example, at the end edge 32a3, so that the cylinder opens and the outer wrapping body 32a becomes a strip. It is preferable to provide an easy-to-tear portion 32a4 such as a perforation at the portion where the outer wrapping body 32a is to be cut.

[0138] 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 for the packaging bag 1 to 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.

[0139] 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.

[0140] The box-shaped outer packaging body 32b accommodates 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 the 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.

[0141] The packaging bag 1 may be accommodated in an outer packaging body 32c having a shape shown in FIG. 39. The outer packaging body 32c is rectangular, and the packaging bag 1 is accommodated in the outer packaging body 32c without being fixed to the outer packaging body 32c. An easy-to-tear portion 32c4 such as a perforation is provided on the upper surface portion 32c3 of the outer packaging body 32c. By cutting the upper surface portion 32c3 along the easy-to-tear portion 32c4, as shown in FIG. 40A, the lid portion 32c5 surrounded by the easy-to-tear portion 32c4 can be opened. The portion of the upper surface portion 32c3 other than the lid portion 32c5 becomes a covering portion 32c9 that covers the packaging bag 1. It is preferable that the lid portion 32c5 is connected to one side portion 32c7 of the outer packaging body 32c at one side edge 32c6 of the upper surface portion 32c3.

[0142] In the outer packaging body 32c, the bottom surface portion 2 is in a state in which it is shifted toward the other side surface portion 32c8 side in the outer packaging body 32c. The other side surface portion 32c8 is a side surface portion facing the one side surface portion 32c7. The peripheral surface portion 21 is in a state in which it is laid down toward the rear edge 2d side. The contents W are arranged in a position shifted toward the other side surface portion 32c8 side. A folded-back portion 21a is provided in the vicinity of the upper end of the peripheral surface portion 21, where the peripheral surface portion 21 is folded back, and the packaging bag 1 is compactly accommodated in the outer packaging body 32c.

[0143] When heating, as shown in FIG. 40A, the lid portion 32c5 is opened to provide the opening 32c1, and the packaging bag 1 and the outer wrapping body 32c are placed in a microwave oven to start heating. When the packaging bag 1 expands due to steam generated from the contents W, as shown in FIG. 40B, the fold-back portion 21a unfolds and the peripheral portion 21 rises and tries to go out of the outer wrapping body 32c through the opening 32c1. At this time, the front portion 3 abuts against the edge 32c2 of the opening 32c1, and the packaging bag 1 further expands in this state, so that a force acts to move the bottom portion 2 toward the one side portion 32c7 (the right side in FIG. 40B), and the bottom portion 2 moves toward the one side portion 32c7 due to the force. As a result, most of the bottom portion 2 is positioned in a position facing the opening 32c1, and only a part of the bottom portion 2 near the front edge 2c is covered with the covering portion 32c9. Preferably, the bottom portion 2 moves until the rear edge 2d of the bottom portion 2 reaches the one side surface portion 32c7. Moreover, the packaging bag 1 expands while the bottom portion 2 curves so that both ends in the left and right direction are lifted as shown in FIG. 2B.

[0144] 40C, when the packaging bag 1 further expands, the peripheral portion 21 tries to rise further, and at that time, the front edge 2c tries to rise. However, since the front edge 2c is disposed at a position covered by the covering portion 32c9, when the front edge 2c rises, a portion of the front surface portion 3 adjacent to the front edge 2c (e.g., the front facing portion 3c) abuts against the edge 32c2 of the opening 32c1, suppressing the lifting of the front edge 2c and promoting the rising of the peripheral portion 21.

[0145] In this manner, according to the present embodiment, the outer packaging body 32c can promote the rising of the peripheral portion 21 without fixing the packaging bag 1 to the outer packaging body 32c. In addition, since the outer packaging body 32c promotes the rising of the peripheral portion 21, it is not necessary to attach the reinforcing member 27 to the packaging bag 1.

[0146] The packaging bag 1 may be housed in an outer packaging body 8 having a shape shown in FIG. 46. The outer packaging body 8 is a rectangular parallelepiped, and the packaging bag 1 is housed in the outer packaging body 8 without being fixed to the outer packaging body 8. The outer packaging body 8 can be made from a sheet 8a shown in the development view of FIG. 47. The outer packaging body 8 has a bottom surface portion 8b, a long side surface portion 8c, a short side surface portion 8d, and an upper surface portion 8e. The bottom surface portion 8b is connected to the long side surface portion 8c and the short side surface portion 8d. The bottom surface portion 8b and the upper surface portion 8e are connected via the short side surface portion 8d. A pair of first overlap margins 8f are connected to each short side surface portion 8d. A second overlap margin 8g is connected to each long side surface portion 8c. A third overlap margin 8h is connected to the upper surface portion 8e. The long side portion 8c and the short side portion 8d can be joined to each other by adhering them at the first overlap margin 8f. The top surface portion 8e can be joined to the long side portion 8c by adhering them at the second overlap margin 8g. The top surface portion 8e can be joined to the short side portion 8d at the third overlap margin 8h. In this manner, the outer packaging body 8 can be manufactured from the sheet 8a by adhering them at the first to third overlap margins 8f, 8g, 8h.

[0147] As described later, it is assumed that the upper surface portion 8e will peel off from the second overlap 8g as the contents in the packaging bag 1 are heated. For this reason, it is preferable that the adhesive member (adhesive, adhesive, double-sided tape, etc.) for adhering the upper surface portion 8e to the second overlap 8g has an adhesive strength that does not peel off during transportation but peels off as the packaging bag 1 expands. In addition, it is preferable that this adhesive member has an adhesive strength that decreases at high temperatures and contains a component that generates heat in microwaves. Examples of such components include inorganic materials such as indium oxide, aluminum, tin, nickel, and carbon, and conductive organic compounds such as polyanilines and polypyrroles.

[0148] The upper surface portion 8e of the outer packaging body 8 is provided with an easy-to-tear portion 8i such as a perforation, and the upper surface portion 8e can be divided into first and second upper surface portions 8e1, 8e2 by cutting the upper surface portion 8e along the easy-to-tear portion 8i. In this embodiment, a pair of easy-to-tear portions 8i is provided, and the strip portion 8e3 between the pair of easy-to-tear portions 8i can be removed by cutting the upper surface portion 8e along the pair of easy-to-tear portions 8i. Before heating, the first and second upper surface portions 8e1, 8e2 are in a state of being adhered to the second overlapping portion 8g.

[0149] As shown in Fig. 46, the bottom surface portion 2 is disposed so as to cover almost the entire bottom surface portion 8b within the outer packaging body 8. The peripheral surface portion 21 is in a state of being laid down towards the rear edge 2d side.

[0150] When heating, the upper surface portion 8e is cut along the easy-to-tear portion 8i to remove the belt-shaped portion 8e3, and then the packaging bag 1 and the outer packaging body 8 are placed in a microwave oven and heating is started. When the packaging bag 1 expands due to steam generated from the contents W, as shown in FIG. 48, the peripheral surface portion 21 rises and pushes up the first and second upper surface portions 8e1, 8e2, thereby peeling the first and second upper surface portions 8e1, 8e2 from the second overlapping portion 8g. In the initial stage of expansion, the front edge 2c of the packaging bag 1 tends to rise and fall over, but in the initial stage of expansion, the first and second upper surface portions 8e1, 8e2 prevent the front edge 2c from rising up, so that the configuration of this embodiment prevents the packaging bag 1 from falling over when heated. As shown in FIG. 49, when the packaging bag 1 further expands, the peripheral surface portion 21 rises further and the back surface portion 4 opens.

[0151] Incidentally, in the packaging bag 1 in which the peripheral portion 21 is folded down toward the rear edge 2d side, the back portion 4 is not visible before heating, but becomes visible when the back portion 4 is unfolded following heating. For this reason, by printing a pattern on the back portion 4 or attaching a sheet 47 having such a pattern to the back portion 4, the pattern can be made to appear on the back portion 4 side as the peripheral portion 21 rises up, and the appeal of the packaging bag 1 can be enhanced.

[0152] Furthermore, the pattern that appears on the back part 4 can be linked to the pattern 8j displayed on the outer wrapping body 8. For example, if the pattern 8j on the outer wrapping body 8 is an animal (e.g., a dinosaur) egg and the pattern that appears on the back part 4 is an animal hatching from the egg, it is possible to present a story in which an animal hatches from an egg as the product is heated, which is highly creative.

[0153] 9. Ninth embodiment In the ninth embodiment, a method and device for attaching a reinforcing member 27 will be described with reference to FIGS.

[0154] The packaging bag 1 to which the reinforcing member 27 is attached can be manufactured, for example, by the method described in "1.3. Manufacturing method of packaging bag". In this method, as shown in Fig. 4 and Figs. 9 to 10, the bottom film 20a is folded into a V-shape at the center line E1 and inserted between the film to be the front part 3 and the film to be the back part 4 and welded, so that a crease due to the center line E1 is easily formed in the bottom part 2. Although this method has an advantage such as being easy to form the gradient part 13c shown in Fig. 3, it is easy to cause a problem that it is difficult to attach the reinforcing member 27 if there is a crease in the bottom part 2. In this embodiment, in order to solve such a problem, the reinforcing member 27 is attached in a state in which the four sides of the bottom part 2 are supported using a holding jig 44 shown in Fig. 41, so that even if there is a crease in the bottom part 2, it is possible to attach the reinforcing member 27 with high precision and high efficiency.

[0155] FIG. 41 shows a holding jig 44 that holds the packaging bag 1 when attaching the reinforcing member 27. The holding jig 44 includes first to fourth support parts 44a to 44d, a base 44e, and a hinge 44f. The first support part 44a is rotatable about the hinge 44f, and the first support part 44a can be displaced between a held state shown in FIG. 41A and a released state shown in FIG. 41B. The second to fourth support parts 44b to 44d are fixed to the base 44e such that a gap 44g is provided between the base 44e and the first support part 44a. As shown in FIGS. 42A to 42B, the bottom part 2 of the packaging bag 1 can be inserted into the gap 44g. The second and third support parts 44b and 44c are arranged to extend parallel to each other with a gap therebetween, and are configured to be able to support a pair of short side parts 2l of the bottom part 2. The fourth support portion 44d is disposed between the second and third support portions 44b, 44c so as to extend perpendicularly to the second and third support portions 44b, 44c. The fourth support portion 44d is configured to be able to support one of the long side portions 2m of the bottom portion 2. The other of the long side portions 2m of the bottom portion 2 is configured to be able to be supported by the first support portion 44a in a holding state as shown in Figs. 41A and 43. The short side portion 2l and the long side portion 2m are portions adjacent to the short side and long side of the periphery of the rectangular bottom portion 2, respectively.

[0156] As shown in FIG. 42A, the packaging bag 1 is held by the holding jig 44 with the peripheral portion 21 folded down toward the rear edge 2d and the bottom portion 2 facing upward. When the bottom portion 2 of the packaging bag 1 is held by the holding jig 44, first, as shown in FIG. 42A, the first support portion 44a is released, and in this state, the bottom portion 2 is pushed into the gap 44g from the ends of the second and third support portions 44b, 44c, so that three sides of the bottom portion 2 are supported by the second to fourth support portions 44b to 44d, as shown in FIG. 42B. Next, as shown in FIG. 43, the first support portion 44a is rotated to be held. As a result, the four sides of the bottom portion 2 are supported by the first to fourth support portions 44a to 44d. The bottom portion 2 is exposed from an opening 44h surrounded by the first to fourth support portions 44a to 44d. The overlap width between the first to fourth support parts 44a to 44d and the bottom part 2 is, for example, 1 to 10 mm, and preferably 2 to 8 mm (5 mm in this embodiment). This value is specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm, and may be in the range between any two of the values ​​exemplified here. The opening 44h has a shape in which the bottom part 2 is narrowed by the overlap width.

[0157] Next, as shown in Fig. 44A, the holding jig 44 holding the packaging bag 1 is placed on an adhesive application device 45. The adhesive application device 45 includes a nozzle 45a capable of discharging adhesive 45d, a guide rail 45b, and a transport table 45c. The transport table 45c is configured to be movable along the guide rail 45b. The holding jig 44 is placed on the transport table 45c. The holding jig 44 can be fixed to the transport table 45c by, for example, a clamp mechanism.

[0158] In the adhesive application process, first, the conveyance table 45c to which the holding jig 44 is fixed is moved to a first position shown in FIG. 44B, and the adhesive 45d is discharged from the nozzle 45a at the first position to apply it to the bottom surface portion 2. In this embodiment, the adhesive 45d is applied from the two nozzles 45a to two locations adjacent to one of the short sides 2l of the bottom surface portion 2. Positioning at the first position is preferably performed by a positioning mechanism (not shown). As the positioning mechanism, for example, a mechanism that engages with a concave-convex shape when the conveyance table 45c reaches the first position is preferable. In addition, this concave-convex engagement is preferably disengaged when a force exceeding a predetermined threshold value is applied to the conveyance table 45c. With this configuration, after application of the adhesive 45d at the first position is completed, the conveyance table 45c can be quickly moved to the second position.

[0159] Next, the conveyor 45c is moved along the guide rail 45b to a second position shown in FIG. 44C, and at the second position, the adhesive 45d is discharged from the nozzle 45a to apply it to the bottom surface portion 2. In this embodiment, the adhesive 45d is applied from the two nozzles 45a to two locations adjacent to the other short side portion 2l of the bottom surface portion 2. In the above process, the adhesive 45d can be applied to the four corners of the bottom surface portion 2. The positioning at the second position is preferably performed by a positioning mechanism (not shown). As the positioning mechanism, for example, a mechanism that abuts against the conveyor 45c when the conveyor 45c reaches the second position to prevent further movement can be mentioned.

[0160] After that, the conveyor 45c is moved from the second position to the installation position shown in FIG. 44A, and then the holding jig 44 is removed from the adhesive application device 45. If the adhesive 45d has a high viscosity such as a hot melt adhesive, stringiness may occur in the adhesive 45d when the holding jig 44 is moved from the first position to the second position or from the second position to the installation position. If the stringy resin generated by this stringiness protrudes from the bottom surface portion 2, the appearance of the packaging bag 1 will be significantly deteriorated. However, in this embodiment, the nozzle 45a moves relatively toward the center in the longitudinal direction of the bottom surface portion 2 both in the movement from the first position to the second position and in the movement from the second position to the installation position, so that even if stringiness occurs, the stringy resin generated by the stringiness is prevented from protruding from the bottom surface portion 2.

[0161] The adhesive 45d may be applied by another method. For example, the adhesive 45d may be applied to two locations adjacent to one long side 2m of the bottom surface portion 2, and then the adhesive 45d may be applied to two locations adjacent to the other long side 2m of the bottom surface portion 2. In this case, the nozzle 45a moves relatively toward the center of the short side of the bottom surface portion 2 both when moving from the first position to the second position and when moving from the second position to the installation position. Even in this case, the resin threads are prevented from spilling out of the bottom surface portion 2.

[0162] Next, as shown in FIG. 45A, reinforcing member 27 is placed on bottom surface portion 2 after adhesive 45d has been applied. Reinforcing member 27 preferably has the same shape as opening 44h, or a shape in which opening 44h is slightly narrowed (for example, 0.1 to 5 mm). The width by which opening 44h is narrowed is specifically, for example, 0.1, 0.5, 1.0, 1.5, 2, 3, 4, or 5 mm, and may be within a range between any two of the numerical values ​​exemplified here. Reinforcing member 27 is preferably placed so as to overlap adhesive 45d applied on bottom surface portion 2.

[0163] 45B, a pressing portion 46 is placed on the reinforcing member 27, and the reinforcing member 27 is pressed against the bottom surface portion 2 by the pressing portion 46. This spreads the adhesive 45d and increases the adhesion between the reinforcing member 27 and the bottom surface portion 2, completing the attachment process of the reinforcing member 27. This process is preferably performed before the adhesive 45d hardens. The description of the shape of the pressing portion 46 is the same as the description of the shape of the reinforcing member 27.

[0164] 10. Tenth embodiment In the tenth embodiment, a modified example of the lower end welded portion 13 will be described with reference to Figs.

[0165] FIG. 50 shows a packaging bag 1 having a bottom end welded portion 13 of the same shape as in the first embodiment. In FIG. 50, the reinforcing member 27 is not provided, but the reinforcing member 27 may be provided. In this embodiment, in both the gradient portion 13c on the leading edge 2c side and the gradient portion 13c on the trailing edge 2d side, the inner edge 13c2 of the gradient portion 13c reaches the side end welded portion 12 at the position of the fold 31. That is, in the side end welded portion 12, the end points 13c3 of the inner edges 13c2 of the gradient portions 13c on the leading edge 2c side and the trailing edge 2d side are aligned. Therefore, in the vicinity of the side end welded portion 12, the gap 2n in the front-rear direction between the inner edges 13c2 of the gradient portions 13c on the leading edge 2c side and the trailing edge 2d side is very narrow.

[0166] 51, the packaging bag 1 is configured such that the peripheral portion 21 is tilted toward the rear edge 2d side, and the peripheral portion 21 rises when steam enters the space 2o between the bottom film 20a and the lower back surface 4a during heating. However, if the reinforcing member 27 is not provided, the contents are solid, or the contents are arranged in an unfavorable state for the peripheral portion 21 to rise, sufficient steam may not enter the space 2o, making it difficult for the peripheral portion 21 to rise.

[0167] The embodiment in Fig. 52 solves this problem, and in at least one of the gradient portions 13c on the leading edge 2c side and the trailing edge 2d side, the end point 13c3 reaches the side end welded portion 12 just before the fold 31. Therefore, in the vicinity of the side end welded portion 12, the gap 2n in the front-to-rear direction between the inner edges 13c2 of the gradient portions 13c on the leading edge 2c side and the trailing edge 2d side is larger than in the embodiment in Fig. 50, and steam flows through the gap 2n, making it easier for steam to enter the space 2o. Therefore, according to the embodiment in Fig. 52, the peripheral portion 21 is more likely to rise.

[0168] 11. Eleventh embodiment In the eleventh embodiment, another modified example of the bottom end welded portion 13 will be described with reference to FIGS.

[0169] Immediately after forming the welds other than the upper end weld 19, the packaging bag 1 is in the state shown in Figure 53A, and from this state, the contents W are filled as shown in Figure 53B, and then the peripheral portion 21 is folded down toward the rear edge 2d, thereby making it possible to manufacture the bag.

[0170] When filling the container with the contents W, the lower end welded portion 13 faces downward as shown in Fig. 53B, and when the peripheral portion 21 is tilted toward the rear edge 2d, it is necessary to invert (i.e. rotate the lower end welded portion 13 outward) so that the lower end welded portion 13 faces horizontally as shown in Fig. 53C. It is desirable for this inversion to be performed smoothly, but as shown in Fig. 54A, when the inner edge 13c2 of the sloped portion 13c of the lower end welded portion 13 is linear, the intersection 13f of the sloped portion 13c and the inner edge of the central portion 13d may have an angular shape, making it difficult for the lower end welded portion 13 to be inverted.

[0171] The embodiment in Fig. 54B solves such a problem, and inner edge 13c2 of gradient portion 13c has a downwardly convex curved shape. Therefore, there is no angular shape in bottom end welded portion 13, and bottom end welded portion 13 can be smoothly inverted. Also, it is preferable that inner edge 13c2 has a downwardly convex curved shape over the entire inner edge 13c2 of bottom end welded portion 13. In this case, there is no straight central portion 13d, and the entire inner edge 13c2 of bottom end welded portion 13 becomes gradient portion 13c.

[0172] If the length of the inner edge 13c2 of the lower end welded portion 13 in the left-right direction is L1, and the length of the linear center portion 13d in the left-right direction is L2, then L2 / L1 is, for example, 0 to 0.5, and more preferably 0 to 0.4. In the embodiment of FIG. 54A, L2 / L1 is about 0.6, and the larger L2 / L1 is, the steeper the gradient of the gradient portion 13c becomes, making it more difficult to invert the lower end welded portion 13. In the embodiment of FIG. 54B, since the center portion 13d does not exist, L2 / L1=0. The value of L2 / L1 is specifically, for example, 0.0, 0.1, 0.2, 0.3, 0.4, or 0.5, and may be within a range between any two of the numerical values ​​exemplified here.

[0173] In the embodiment of FIG. 54A, the outer edge 13c4 of the inclined portion 13c is parallel to the inner edge 13c2, and the air pocket 14 is triangular with a sharp apex, but such a shape also tends to prevent the lower end welded portion 13 from turning over. For this reason, as shown in FIG. 54B, it is preferable that the lower end welded portion 13 does not have an outer edge parallel to the inner edge 13c2 of the inclined portion 13c, and it is preferable that the air pocket 14 has a curved shape at the lower end side of the packaging bag 1. It is more preferable that the air pocket 14 has an arc-shaped lower end side of the packaging bag 1. It is also preferable that the air pocket 14 has a shape without a sharp apex, and it is more preferable that the air pocket 14 is circular, elliptical, or oval. It is preferable to provide a plurality of air pockets 14 at positions adjacent to the left and right ends of the packaging bag 1. EXAMPLES

[0174] 1. Heating test 1-1. Manufacturing method of packaging bags According to the method shown in the first embodiment, a packaging bag 1 having the shape shown in Fig. 1 to Fig. 3 was manufactured. The dimensions H1 to H4 in Fig. 3 were 95 mm, 75 mm, 45 mm, and 200 mm, respectively. The reinforcing member 27 was made of paper having 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.

[0175] 1-2.Water heating test After 200 ml of water at 5°C was placed 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.

[0176] As shown in Table 1, in the "normal" position, the heating time until boiling was much longer in the "vertical" position than in the "horizontal" position and "Rise" position. This result shows that the heating efficiency of the "vertical" position is inferior to that of the "horizontal" and "Rise" positions. In addition, the heating time until boiling was much longer in the "60 mm above" position than in the "normal" position. This result shows that the microwave oven has particularly excellent heating efficiency near the plate.

[0177] [Table 1]

[0178] 1-3. Food heating test Next, hamburger steak (180g) or fried rice (130g) was placed in the packaging bag 1 and stored at the storage temperature shown in Table 2, after which it was heated in a microwave oven at 500W 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 points shown in Table 2 were measured using a thermograph. "Surface (high)" indicates the temperature of the hottest point on the surface of the food. "Surface (low)" indicates the temperature of the coldest point on the surface of the food. "Inside (low)" indicates the temperature of the coldest point 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.

[0179] 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.

[0180] [Table 2]

[0181] 2. Standing up test 2-1. Manufacturing method of packaging bag 1 <Test Examples 1 to 3> According to the method shown in the first embodiment, a packaging bag 1 having a seam 10 of the shape shown in Figures 1 to 3 was manufactured. The internal dimensions of the welded part in the X, Y, and Z directions in Figure 1 were respectively the vertical dimension a, the horizontal dimension b, and the height dimension c of the packaging bag 1, and the packaging bags 1 of Test Examples 1 to 3 were manufactured with these dimensions having the values ​​shown in Table 3.

[0182] <Test Examples 4 to 6> A packaging bag 1 was manufactured in which the structure above the opening portion 24 of the packaging bag 1 having the shape shown in Figures 1 to 3 was changed to the structure shown in Figure 22C. The dimensions of this packaging bag 1 were as shown in Table 3. This packaging bag 1 does not have a seam 10, and has a side end welded portion 12 and an upper end welded portion 19 between the front portion 3 and the back portion 4, and has a steam release seal portion 11 at the side end welded portion 12.

[0183] [Table 3]

[0184] 2-2. Details of the start-up test The packaging bag 1 of each test example was filled with 200 ml of water, and placed in a microwave oven with the peripheral portion 21 lying down as shown in Fig. 8A. It was then heated at 500 W until the bag expanded and steam began to escape, and it was checked whether the peripheral portion 21 would rise up. The rise up test was carried out without the reinforcing member 27 attached to the bottom portion 2.

[0185] For each test example, ten samples were prepared, and each of the ten samples was evaluated according to the following criteria based on whether it stood up or not. ◯: The peripheral surface portion 21 rose in all of the 10 samples. Δ: In samples 1 to 9, the peripheral surface portion 21 rose up. ×: The peripheral portion 21 did not rise in any of the samples.

[0186] As shown in Table 3, it has been found that in a packaging bag 1 having a seam 10, it is preferable that the value V1 calculated by {vertical dimension [a] / height dimension [c]} is 0.82 or more. This value V1 is, for example, 0.82 to 1.50, and specifically, for example, 0.82, 0.85, 0.90, 0.91, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.30, 1.40, 1.50, and may be in a range between any two of the numerical values ​​exemplified here or equal to or greater than any one of them.

[0187] As shown in Table 3, it has been found that the value V1 is preferably 0.55 or more for packaging bags 1 that do not have the joint portion 10. This value V1 is, for example, 0.55 to 1.50, and specifically, for example, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.91, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.30, 1.40, and 1.50, and may be in a range between any two of the numerical values ​​exemplified here or equal to or greater than any one of them.

[0188] The preferable lower limit of value V1 differs depending on whether or not there is a seam 10 for the following reason. When there is a seam 10, the area where the seam 10 is located is less likely to expand, so that the bottom portion 2 of the packaging bag 1 selectively expands and is more likely to float up in the early stage of the expansion of the packaging bag 1, whereas when there is no seam 10, the upper part of the packaging bag 1 also expands, so that the entire packaging bag 1 expands uniformly and the bottom portion 2 is prevented from floating up. For this reason, in order to improve the stand-up ability of a packaging bag 1 with a seam 10, it is necessary to make the vertical dimension [a] larger or the height dimension [c] smaller compared to a packaging bag 1 without a seam 10, and the preferable lower limit of value V1 becomes larger.

[0189] Furthermore, regardless of the presence or absence of the palm portion 10, in consideration of the stability after the peripheral portion 21 stands up, it is preferable that the value V2 calculated by {width dimension [b] / height dimension [c]} is 1.0 or more. This value V2 is, for example, 1.0 to 2.5, specifically, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, and may be in the range between any two of the numerical values ​​exemplified here or equal to or greater than any one of them.

[0190] 3. Standing test of packaging bag 1 containing solids 3-1. Manufacturing method of packaging bag 1 <Test Examples 7 to 9> According to the method shown in the first embodiment, a packaging bag 1 having a seam portion 10 in the shape shown in Figures 1 to 3 was manufactured. The internal dimensions of the welded portion in the X, Y, and Z directions in Figure 1 were the vertical dimension a, horizontal dimension b, and height dimension c of the packaging bag 1, respectively, and the packaging bags 1 of Test Examples 7 to 9 were manufactured with these dimensions having the values ​​shown in Table 4. When the packaging bag 1 of Test Example 8 was filled with water and the volume was measured, it was about 800 mL.

[0191] [Table 4]

[0192] 3-2. Details of the start-up test A hamburger steak (135 g) and sauce (55 g) measuring 8 cm in length, 10 cm in width, and 3.5 cm in thickness were placed in the packaging bag 1 of each test example, and the same test as in "2-2. Details of the rise test" was conducted and evaluated according to the same criteria. The rise test was conducted without attaching the reinforcing member 27 to the bottom portion 2. The results are shown in Table 4.

[0193] As shown in Table 4, it was found that the value V1 calculated by {vertical dimension [a] / height dimension [c]} is preferably 1.15 or more, and more preferably 1.25 or more. This value V1 is, for example, 1.15 to 2.00, specifically, for example, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, and may be in the range between any two of the numerical values ​​exemplified here.

[0194] Comparing Test Examples 1 to 3 and 7 to 9, when the contents contained solid matter, the peripheral surface portion 21 was less likely to rise up, so the preferable lower limit value of V1 in Test Examples 7 to 9 was larger than that in Test Examples 1 to 3.

[0195] In Test Examples 7 to 9, the ratio of the contents to the content volume was about 24% by mass, and the ratio of the solid content to the entire contents was about 71% by mass. The ratio of the contents to the content volume is, for example, 10 to 50% by mass, and preferably 15 to 40% by mass. This ratio is specifically, for example, 10, 15, 20, 25, 30, 35, 40, 45, or 50% by mass, and may be in a range between any two of the numerical values ​​exemplified here. The ratio of the solid content to the entire contents is, for example, 50 to 100% by mass, and preferably 60 to 80% by mass. This ratio is specifically, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be in a range between any two of the numerical values ​​exemplified here. The solid content contained in the contents may be one or divided into multiple parts. When the solid content is divided into a plurality of portions, it is preferable that the proportion of the largest of the plurality of portions is the above-mentioned proportion of solid content relative to the entire content.

[0196] In addition, all of the above test examples 1 to 9 were performed without attaching the reinforcing member 27 to the bottom portion 2, and the rise-up property was evaluated in the absence of the reinforcing member 27. On the other hand, when the rise-up test was performed with a paper reinforcing member 27 having a thickness of 0.68 mm attached to the bottom portion 2 of the packaging bags 1 in test examples 1 to 9, the evaluation results were all good. [Explanation of symbols]

[0197] 1: Packaging bag 2: Bottom part 2a: 1st bottom part 2b: 2nd bottom part 2c: Leading edge 2d: trailing edge 2e:Protruding piece 2f: Opening 2g: part 2j: Inner rim 2k :Pocket 2l:Short side 2m: Long side 2n: gap 2o :Space 3: Front part 3a: lower front 3a1 :Extension part 3a2: overlapping part 3b: Upper front 3c: Front facing part 4: Back part 4a: Lower back 4a1: Extension 4a2: overlapping part 4b: Upper back 5: Cut-out section 6: Main body 7:Aperture 8: Outer packaging 8a:Sheet 8b: Bottom part 8c:Long side part 8d:Short side part 8e:Top part 8e1: 2nd top surface part 8e2: 2nd top surface part 8e3: Belt 8f: First overlap 8g: Second glue margin 8h: 3rd margin 8i: Easy cutting part 8j:Picture 10: Gassho part 10a: overlapping part 11: Steam release seal 11a: Donut-shaped steam release seal 11b: Unwelded area 11c: Ventilation section 12: Side end welding part 12a: Inner border 13: Lower end welding part 13a: Unwelded area 13b: Opening 13c: Gradient section 13c1 :Starting point 13c2: Common-law marriage 13c3: End point 13c4: Outer edge 13d: Center 13e: Common Marriage 13f: Intersection 14: Air pocket 19: Upper end welding part 20a: Bottom film 20a1:Top surface 20a2: Bottom surface 20a3: Leading edge 20a4 : Trailing edge 20b: Peripheral wall film 20c: Film 20d: Reinforcement film 20f: Leading edge 20g: trailing edge 20h:Pocket 20i: Welded part 20j: Bottom end 20k : Cover film 20l: Welded part 21: Peripheral part 21a: Folded part 22: Opening 23: Opening and closing parts 23a: Front side engagement member 23a1: Base 23a2: Hook part 23b: Rear side engagement member 23b1 : Base 23b2: Hook section 24: Opening section 24a:Tear start part 24b: Cutting line 26: Upper opening part 26a:Tear start part 26b: Cutting line 27: Reinforcement member 27a: Chopsticks 27b: Fold 27c: Attachment part 28: Overlapped section 29: Fixing means 29a: Double-sided tape 29b: Adhesive tape 30: General-purpose materials 30a: Plate 31: Fold 32: Outer packaging 32a: Outer packaging 32a1: First covering part 32a2: Second covering part 32a3:Edge 32a4: Easy cutting part 32b: Outer packaging 32b1: Easy cutting part 32b2: Upper part 32b3: 1st easy cutting part 32b4: 2nd easy cutting part 32b5: Cutting piece 32b6: Fold line 32c:Outer packaging 32c1 :Opening 32c2 : Edge 32c3:Top part 32c4: Easy cutting part 32c5: Lid part 32c6 :One side edge 32c7: One side part 32c8: Other side part 32c9: Covering part 41: Fold 42: Plate-shaped member 43: Conveyor 43a: Transport section 43b: Gap 44: Holding jig 44a: 1st support part 44b: Second support part 44c: Third support part 44d: 4th support part 44e: Bass 44f: Hinge 44g : Gap 44h: opening 45: Adhesive application device 45a: Nozzle 45b: Guide rail 45c: Transport platform 45d: Adhesive 46: Pressing part B :Area 47:Sheet C: ring C1: One end C2: Other end D : Ring D1: Location D2: End P1 : Part 1 P2 : Part 2 P3 : Part 3 S : Confined space W: Contents

Claims

1. A packaging bag for a microwave oven, in which a flexible film is formed into a bag shape, A bottom surface portion and a peripheral surface portion, The peripheral surface portion includes a front surface portion and a rear surface portion that face each other and are provided so as to rise from the bottom surface portion, The front surface and the rear surface are configured to be inclined integrally toward the front or rear of the packaging bag relative to the bottom surface, The packaging bag has a bottom portion that is expandable.

2. A packaging bag as described in claim 1, The packaging bag is configured to have an enclosed space inside by welding the bottom portion, the front portion, and the back portion to each other, the front surface portion includes a front surface lower portion and a front surface upper portion, the front surface lower portion is welded to the bottom surface portion, and the front surface lower portion and the front surface upper portion are welded to each other at a joint portion formed by overlapping inner surfaces of these portions, The front-to-rear direction of the bottom surface portion is the X direction, the height direction of the peripheral surface portion is the Z direction, and the dimensions of the sealed space in the X direction and the Z direction are the vertical dimension [a] and the height dimension [c], respectively. A packaging bag in which the value V1 calculated by {the vertical dimension [a] / the height dimension [c]} is 0.82 or more.

3. A packaging bag as described in claim 2, The packaging bag, wherein V1 is 0.82 to 1.

50.

4. A packaging bag as described in claim 1, The packaging bag is configured to have an enclosed space inside by welding the bottom portion, the front portion, and the back portion to each other, the front surface is made of a single film, The front-to-rear direction of the bottom surface portion is the X direction, the height direction of the peripheral surface portion is the Z direction, and the dimensions of the sealed space in the X direction and the Z direction are the vertical dimension [a] and the height dimension [c], respectively. A packaging bag in which the value V1 calculated by {the vertical dimension [a] / the height dimension [c]} is 0.55 or more.

5. A packaging bag according to claim 4, The packaging bag, wherein V1 is 0.55 to 1.

50.

6. The packaging bag according to any one of claims 1 to 5, A packaging bag comprising a steam release seal portion that forms a steam flow path as the internal pressure of the packaging bag increases.

7. The packaging bag according to any one of claims 1 to 5, It has an enclosed space inside to store the contents, The packaging bag is configured so that the sum of the weight of the portion of the peripheral portion below the center line of the sealed space in the vertical direction of the packaging bag and the weight of the bottom portion is greater than the weight of the portion of the peripheral portion above the center line of the sealed space.

8. The packaging bag according to claim 1, the bottom surface portion is constituted by a bottom film, The packaging bag has a bottom portion provided with a reinforcing member that reinforces the bottom portion so as to suppress bending of the bottom film.

9. A packaging bag according to claim 8, The packaging bag, wherein the reinforcing member can be attached to the bottom portion of another packaging bag after being removed from the bottom portion.

10. 1. A method for preparing a packaged food product, comprising: A heating process is provided. The packaged food comprises the packaging bag according to any one of claims 1 to 5 and food contained in the packaging bag, In the heating step, the bottom surface is unfolded and placed on the ground, and the peripheral surface is tilted at an angle of 30° or less relative to the horizontal plane, and heating of the food contained in the packaging bag is then started in a microwave oven.

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