JP2022118996A - Packaging bag and packaged food - Google Patents

Abstract

To provide a standing-type packaging bag capable of properly discharging steam generated by microwave heating while having a simple and easily-manufacturable structure, and packaged food.SOLUTION: A standing-type packaging bag 101 of the invention has: a front sheet 1A; a back sheet 1B; and a bottom sheet 1C constituting a two-folded gusset section. Only the front sheet 1A has a steam opening forming resin layer 4 for adjusting lamination strength so that a steam opening 11 for discharging steam generated by microwave heating of food F from an accommodation space 7 is formed in part of a gusset seal portion 9. The bottom sheet 1C has punched holes 9a so that the front sheet 1A and the back sheet 1B are heat-sealed in an overlap region 12 between a side seal portion 8 and the gusset seal portion 9.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a packaging bag and a packaged food, and for example, relates to a microwave heating packaging bag made of a heat-sealed laminated film and a microwave heating packaged food in which food is sealed and packaged in the packaging bag. is.

BACKGROUND ART Packaged foods for heating in a microwave oven, which contain retort foods, frozen foods, and the like, are widely used. When this packaged food is microwave-heated, the moisture contained in the contents evaporates with the heating, and the generated steam increases the pressure inside the packaging bag. If the pressure inside the packaging bag increases, there is a risk that the packaging bag will tear and the contents will scatter and contaminate the inside of the microwave oven. Therefore, a standing-type packaging bag having a steam release mechanism has been proposed in order to release the steam generated by microwave heating to the outside of the packaging bag (see, for example, Patent Documents 1 and 2).

WO2013133092 A1 JP 2004-250046 A

A standing-type packaging bag such as that proposed in Patent Document 1 is designed to be heated in a microwave oven in a standing state. However, if a solid content such as a hamburger is stuck in the middle of the packaging bag or the like, it may tip over when the packaging bag swells during microwave heating. Moreover, since the vapor release mechanism is constructed by protruding a part of the side seal portion toward the accommodation space, it is difficult to fill the accommodation space with a large solid object.

In the standing-type packaging bag proposed in Patent Document 2, since the gusset portion forming the bottom surface is provided with a vapor release mechanism, even large solids can be easily filled. In addition, since the packaged food is placed horizontally and heated in the microwave, there is no need to worry about tipping over. However, since the vapor release mechanism is constructed by using the easily peelable tape-like film as a separate member, the structure of the gusset portion and its manufacturing process are complicated. As a result, the possibility of liquid leakage from the steam port during or after microwave heating also increases.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a standing structure that has a simple and easy-to-manufacture structure and that can properly discharge steam generated during microwave heating. To provide a type of packaging bag and packaged food.

In order to achieve the above object, the packaging bag of the first invention is a standing type microwave heating bag made by heat-sealing laminated films so that a storage space for storing contents is formed inside the packaging bag. A packaging bag for
The laminated film includes a front sheet, a back sheet facing the front sheet through the accommodation space, and a bottom sheet forming a double-fold gusset between the front sheet and the back sheet. death,
The seal portions formed by the heat sealing include a side seal portion formed by the front sheet and the back sheet, and a gusset seal portion formed by each of the front sheet and the back sheet and the bottom sheet; has
A steam port-forming resin layer for adjusting lamination strength is formed on the front sheet so that a steam port for discharging steam generated by microwave heating of the contents from the accommodation space is formed in a part of the gusset seal portion. and on only one of said backsheets,
A hole is formed in the bottom sheet so that the front sheet and the back sheet are heat-sealed in an overlapping region between the side seal portion and the gusset seal portion.

A packaging bag according to a second invention is the packaging bag according to the first invention, wherein the steam port forming resin layer is formed so as to cross the gusset seal portion from the inner side of the inner edge of the gusset seal portion to the outer edge of the gusset seal portion. characterized by being formed

A packaging bag of a third invention is the packaging bag of the first or second invention, wherein the laminated film has a laminated structure including a substrate layer, an adhesive layer and a sealant layer, and the steam port forming resin layer comprises the The laminate strength between the base material layer and the sealant layer is high under room temperature environment and low under high temperature environment.

A packaging bag according to a fourth invention, in any one of the first to third inventions, has a length in the width direction of the packaging bag of 130 to 160 mm, and a seal width of the side seal portion of 10 mm or more, The seal width at the widthwise center of the gusset seal portion is less than 10 mm, and the steam port forming resin layer has a rectangular coating shape and is positioned at the widthwise center of the gusset seal portion. and

A packaging bag according to a fifth invention is the packaging bag according to any one of the first to fourth inventions, in which the steam bag is placed horizontally in a state in which the front sheet is positioned on the upper side and the back sheet is positioned on the lower side. A mouth-forming resin layer is positioned on the front sheet.

A packaged food according to a sixth aspect of the invention is a packaged food for heating in a microwave oven, and includes a packaging bag according to any one of the first to fifth aspects of the invention, and a state in which the content is accommodated in the accommodation space. and a food hermetically packaged with

According to the present invention, only one of the front sheet and the back sheet has a steam port forming resin layer for adjusting lamination strength so that the steam port is formed in a part of the gusset seal portion. Therefore, the steam generated by microwave heating of the contents is discharged from the steam port located on one side of the gusset seal portion. Therefore, it is possible to properly discharge the steam generated by microwave heating, while having a simple and easy-to-manufacture configuration that does not require separate members. For example, if the packaged food is arranged so that the front sheet having the steam port forming resin layer is positioned on the upper side and the back sheet is positioned on the lower side, the contents below are placed on the upper side of the steam port. will be located away from Therefore, even if the content contains a large amount of liquid, it is possible to prevent the liquid from leaking from the steam port during or after microwave heating.

In addition, in the overlapping region of the side seal portion and the gusset seal portion, the bottom sheet has a hole so that the front sheet and the back sheet are heat-sealed, so the packaging bag swelled due to microwave heating. At this time, it is possible to avoid concentration of the internal pressure at the intersection of the side seal portion and the gusset seal portion. Therefore, it is possible to set the concentration position of the internal pressure to the position of the steam port forming resin layer. It is possible to smoothly discharge from the steam port.

BRIEF DESCRIPTION OF THE DRAWINGS The external view which shows one embodiment of the packaging bag for a microwave oven heating, and a packaged food. FIG. 1(A) is a cross-sectional view taken along the line L1-L1′ and a cross-sectional view showing a portion D thereof. Fig. 1(B) is a cross-sectional view of a main part showing the state of the packaged food in Fig. 1(B) being microwave-heated.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, packaging bags, packaged foods, etc. according to embodiments of the present invention will be described with reference to the drawings. In addition, the same reference numerals are given to the same parts or corresponding parts in each embodiment, specific example, etc., and duplication of explanation will be omitted as appropriate.

FIG. 1 schematically shows schematic structures of a packaging bag 101 and a packaged food 201 according to the embodiment, and FIG. 2 schematically shows a cross-sectional structure of the packaging bag 101. As shown in FIG. In FIG. 1, (A) is a plan view showing a standing-type packaging bag 101 in a folded state, and (B) is a front view showing a packaged food 201 in which food F is sealed in the packaging bag 101. . In FIG. 2, (A) is a cross-sectional view taken along line L1-L1' of FIG. 1(A), and (B) is a cross-sectional view showing part D in FIG. 2(A).

The packaging bag 101 is composed of three sheets, a front sheet 1A, a back sheet 1B, and a bottom sheet 1C, all of which are made of laminated films. Then, the laminated film is heat-sealed (thermally bonded) to form a standing pouch so that a storage space 7 for storing food F as a content is formed inside the packaging bag. Therefore, it is possible to manufacture using a general standing pouch bag making machine, and the heat seal is within a range that does not impair the properties and functions of the product when making bags with a continuous bag making machine that manufactures actual products. It is performed under sealing temperature conditions.

The front sheet 1A and the back sheet 1B are arranged so as to face each other with an accommodation space 7 interposed therebetween, and are heat-sealed at the left and right peripheries in a superimposed state. A bottom sheet 1C forming a two-fold gusset portion between the sheets is heat-sealed at the peripheries thereof to the lower ends of the front sheet 1A and the back sheet 1B. However, the upper edges of the front sheet 1A and the back sheet 1B are not sealed. That is, in the packaging bag 101, the side seal portions 8 are formed by heat-sealing the front sheet 1A and the back sheet 1B, and the gussets are formed by heat-sealing the front sheet 1A and the back sheet 1B with the bottom sheet 1C. An accommodation space 7 is formed by the sealing portion 9, and an opening 10h is formed above the accommodation space 7. As shown in FIG.

In the lower portion of the side seal portion 8 (upper side of the gusset seal portion 9), linear cuts 8a are formed on the left and right peripheral edges to serve as starting points for unsealing. The shape of the cut 8a is not limited to a linear shape, and may be V-shaped, U-shaped, or the like. Moreover, the position of the cut 8a is preferably set so that the tearing direction from the cut 8a coincides with the easy-to-tear linear direction of the laminated film.

The laminated film (the front sheet 1A, the back sheet 1B, and the bottom sheet 1C) constituting the packaging bag 101 includes a base material layer 2 as an outer layer and a sealant layer 6 as an inner layer, as shown in FIG. and a printing ink layer 3, an adhesive layer 5 and the like provided therebetween. That is, the laminated film has a laminated structure including the substrate layer 2, the printing ink layer 3, the adhesive layer 5, and the sealant layer 6 from the outside of the packaging bag to the inside of the packaging bag. Further, in the front sheet 1A, inside the printing ink layer 3, a vapor port forming resin layer 4 for lamination strength adjustment is formed so as to straddle the gusset seal portion 9 (FIG. 1), and the content (food F) is formed. A steam port 11 for discharging (steaming) steam generated by microwave heating from the housing space 7 is formed in a part of the gusset seal portion 9 . In other words, the steam port forming resin layer 4 corresponds to the area where the steam port 11 is to be formed.

The base material layer 2 is required to have strength to withstand loads such as printing work, refrigerated storage, microwave heating, etc. Therefore, it is possible to use a synthetic resin film having excellent mechanical, physical and chemical properties. preferable. From such a point of view, specific examples of the substrate layer 2 include polyamide films such as biaxially oriented nylon (ONY) films (those having oxygen barrier properties as necessary).

The sealant layer (thermoadhesive resin layer) 6 is provided for bonding two laminated films together to form a storage space 7 and for sealing the food F therein. The bonding is performed by bringing the sealant layers 6 into contact with each other and heating (melting point: about 120° C.). Therefore, the sealant layer 6 is located at the innermost side of the packaging bag 101 when the bag is manufactured (FIG. 2(B)). As the sealant layer 6, a material suitable for the physical properties required for the packaging bag 101 can be appropriately selected and used. However, in the region where the steam port forming resin layer 4 is located, it is necessary to use a material that causes breakage for steaming, which will be described later. From this point of view, specific examples of the sealant layer 6 include polyethylene films such as linear low-density polyethylene (LLDPE) films and low-density polyethylene (LDPE) films.

The printing ink layer 3 is formed of colored inks, and specific examples thereof include a pattern layer and a white ink layer. The adhesive layer 5 is formed of, for example, a dry lamination adhesive generally used in the dry lamination method. Specific examples of adhesives include polyvinyl acetate adhesives, polyacrylate adhesives, cyanoacrylate adhesives, ethylene copolymer adhesives, cellulose adhesives, polyester adhesives, and polyamide adhesives. , amino resin-based adhesives, epoxy-based adhesives, polyurethane-based adhesives, and the like.

The steam port forming resin layer 4 is a heat-softening resin layer having a property that it has a predetermined lamination strength at an environmental temperature of room temperature (about 30° C.) or lower, but the strength decreases at a high environmental temperature. The environmental temperature at which the above-mentioned predetermined strength is obtained is usually the environmental temperature in the packaging process for packaging the contents, the environmental temperature in the process of refrigerating or freezing the packaging bag containing the contents, and the transportation/storage in a refrigerated/frozen state. At such an environmental temperature, the vapor port forming resin layer 4 maintains a predetermined strength. In addition, the high environmental temperature at which the predetermined strength decreases is the temperature generated when the packaging bag 101 in which the contents are sealed and packaged is heated and cooked in a microwave oven. 4 strength will decrease. Therefore, by forming the vapor port forming resin layer 4, the lamination strength between the base material layer 2 and the sealant layer 6 in the forming region increases under room temperature environment and decreases under high temperature environment.

As the material for the vapor port forming resin layer 4 having the properties described above, it is preferable to use a thermosoftening resin (such as release varnish) having a melting point of 60 to 90°C. Specific examples thereof include nitrocellulose-polyamide resin, polyamide-nitrocellulose-polyethylene wax resin, ethylene-vinyl acetate copolymer resin, and the like. By using a heat-softening resin having a melting point of 60 to 90° C., delamination due to steaming, which will be described later, can easily occur in the vapor port forming resin layer 4 when the resin is heated and cooked in a microwave oven. Therefore, the coating amount of the material used for the vapor port forming resin layer 4 can be extremely small. Since a separate member such as an easily peelable tape is not required, the structure is simple and easy to manufacture, and the cost can be reduced.

The steam port forming resin layer 4 is formed so as to straddle the gusset seal portion 9 as described above. That is, the steam port forming resin layer 4 is applied to the gusset seal portion 9 from the inside of the inner edge of the gusset seal portion 9 in a portion of the gusset seal portion 9 between the printing ink layer 3 and the adhesive layer 5 of the front sheet 1A. It is formed so as to cross the gusset seal portion 9 to the outer edge. A vapor port forming resin layer 4 may be provided on the backsheet 1B in a similar formation area. However, the vapor port forming resin layer 4 is formed only on one of the front sheet 1A and the back sheet 1B.

When cooking is performed in a microwave oven, the internal pressure rises due to steam (eg, water vapor) generated from the contents (food F), and the packaging bag 101 is strongly swollen. Due to the decrease in strength of the vapor port forming resin layer 4 due to the above-described high temperature environment, the adjacent sealant layer 6 receives a large load, stretches and breaks. This is the boundary between the region where the steam port forming resin layer 4 is provided and the region where it is not provided, or the region where the sealant layers 6 are bonded to each other in the region where the steam port forming resin layer 4 is provided. This is because cracks are likely to occur at the boundary with the non-bonded area. Delamination progresses from this fractured portion due to the internal pressure. In other words, the peeling between the layers of the steam port forming resin layer 4 progresses from the inner edge of the gusset seal portion 9 or the inside thereof to the outer edge of the gusset seal portion 9 . When the delamination reaches the outer edge of the gusset seal portion 9, the steam in the housing space 7 is released from the steam port 11 to the outside, and the internal pressure of the packaging bag 101 is reduced.

Punched holes 9a are provided in the bottom sheet 1C so that the front sheet 1A and the back sheet 1B are heat-sealed in the overlap region 12 (FIG. 1) between the side seal portions 8 and the gusset seal portions 9. As shown in FIG. Therefore, when the packaging bag 101 expands due to microwave heating, it is possible to avoid concentration of the internal pressure at the intersection of the side seal portion 8 and the gusset seal portion 9 . Therefore, it is possible to set the concentration position of the internal pressure to the position of the vapor port forming resin layer 4 .

In this packaging bag 101, as shown in FIG. 1A, the length X in the width direction of the packaging bag is 130 to 160 mm, the seal width d of the side seal portion 8 is 10 mm or more, and the gusset seal portion 9 is It is assumed that the sealing width y2 at the center in the width direction is less than 10 mm, the vapor port forming resin layer 4 has a rectangular coating shape, and is positioned at the center in the width direction of the gusset seal portion 9. When the steam port forming resin layer 4 is arranged in the center of the width direction of the gusset seal portion 9 in this way, the internal pressure is concentrated at the position of the steam port forming resin layer 4 , so that the steam in the accommodation space 7 can be smoothly discharged from the steam port 11 . Ejection becomes possible. The seal width y2 at the center of the gusset seal portion 9 in the width direction is preferably less than 10 mm, but more preferably 2 to 7 mm from the balance between the time required for steaming and the seal strength during transportation and storage.

The formation of the steam port forming resin layer 4 is preferably performed by gravure printing, and it is preferable to form the steam port forming resin layer 4 simultaneously with the printing ink layer 3 inline. Since the vapor port forming resin layer 4 is formed on the front sheet 1A or the back sheet 1B, which is the body material, it can be formed simultaneously with the printing ink layer 3 in the printing process. Positioning of the bottom sheet 1C with respect to is also easy.

The display (characters, patterns, etc.) formed by the printing ink layer 3 is preferably printed in such a direction that the gusset seal portion 9 is positioned on the upper side. If the display is printed in that direction, the display will be upside down when the packaging bag 101 is placed in a stand state with the gusset portion made of the bottom sheet 1C facing downward. For this reason, when the packaged food 202 is set in the microwave oven in the stand state, the misplacement is noticed and the correct horizontal placement state (the front sheet 1A is positioned on the upper side and the back sheet 1B is positioned on the lower side). status).

The film thickness of the vapor port forming resin layer 4 is preferably 1 μm or more and 5 μm or less. If the film thickness is less than 1 μm, separation between the steam port forming resin layers 4 is less likely to occur during microwave heating. Usually, the laminated film 1 before bag making is supplied in a roll state and bag-shaped by a packaging machine. In the laminated film 1 in a rolled state, the part where the steam port forming resin layer 4 is formed swells, and as a result, the part is stretched, which causes bag-making defects and causes a decrease in yield, and the appearance of the finished bag after bag-making is not good. It could turn out to be bad.

The laminate strength (laminate strength between the base material layer 2 and the sealant layer 6) in the region where the steam port forming resin layer 4 is provided is preferably 0.3 to 2 N/15 mm width at the environmental temperature below room temperature, and is high. It is preferably 0.3 N/15 mm width or less at ambient temperature (environmental temperature of 90° C. or higher). The lamination strength of the region where the steam port forming resin layer 4 is not provided is preferably 1.5 N/15 mm width or more at the environmental temperature below room temperature, and 0.5 N/width at high environmental temperature (environmental temperature of 90° C. or higher). A width of 15 mm or more is preferred.

When an LLDPE film (thickness of 30 μm) is used as the sealant layer 6, the heat seal strength of the region in which the steam port forming resin layer 4 is provided is preferably 7 N/15 mm width or more at the ambient temperature below the room temperature, and at a high ambient temperature. It is preferably 4 N/15 mm width or less at (environmental temperature of 90° C. or higher). In addition, the heat seal strength of the region where the steam port forming resin layer 4 is not provided is preferably 7.0 N/15 mm width or more at the environmental temperature below room temperature, and 3 N/15 mm width at high environmental temperature (environment temperature of 90 ° C. or higher). Width or more is preferable. Under high environmental temperature (environmental temperature of 90° C. or higher), the heat seal strength of the region without the vapor port forming resin layer 4 is 1 N/15 mm compared to the heat seal strength of the region with the vapor port forming resin layer 4. It is preferable to design it to be larger than the width.

When manufacturing the packaged food 201, the food F (assumed contents: frozen/chilled products, fried chicken, etc. ). Then, as shown in FIG. 1B, the front sheet 1A and the back sheet 1B are heat-sealed to form a top seal portion 10, and if necessary, a treatment such as retort heating is performed. A packaged food 201 for heating in a microwave oven, which is hermetically packaged while being housed inside, is obtained. Note that the use of the packaging bag 101 is not limited to retort packaging. Depending on the specific sterilization process and distribution mode, it is for boiling sterilization at a lower temperature (100°C or less) than for retort packaging, for hot packs that sterilize the inner surface of the packaging bag only by raising the temperature of the contents, and for distribution without heat treatment. Applications include refrigeration.

FIG. 3 shows the cross-sectional structure of the main part of the packaged food 201 during microwave heating. When the food F is to be eaten, the packaged food 201 is set in a microwave oven and heated with the front sheet 1A positioned on the upper side and the back sheet 1B positioned on the lower side. The packaging bag 101 has an internal pressure opening type steam release mechanism formed by the steam port forming resin layer 4 located on the front sheet 1A, and the steam V (FIG. 3) in the accommodation space 7 is released from the packaging bag during microwave heating. Since it can escape to the outside, the packaged food 201 before microwave heating is sealed and packaged.

When steam V is generated from food F by microwave heating, the internal pressure of packaging bag 101 increases. The sealant layer 6 stretches and breaks due to the synergistic action (decrease in lamination strength) with the vapor port forming resin layer 4, and delamination progresses starting from this broken portion. When the delamination reaches the outer edge of the gusset seal portion 9, the high-temperature, high-pressure steam V in the accommodation space 7 is exhausted from the steam port 11 to the outside of the packaging bag 101 (arrow mv in FIG. 3), 7 is decompressed. When the heating in the microwave oven is finished, the packaged food 201 is opened by breaking the upper portion of the packaging bag 101 from the notch 8a (FIG. 1), and the food F in the accommodation space 7 is transferred to the tableware.

As described above, only one of the front sheet 1A and the back sheet 1B has the steam port forming resin layer 4 for lamination strength adjustment so that the steam port 11 is formed in a part of the gusset seal portion 9. Then, the steam V generated by microwave heating of the contents is discharged from the steam port 11 located on one side of the gusset seal portion 9 . Therefore, it is possible to appropriately discharge the steam V generated by microwave heating, while having a simple and easy-to-manufacture configuration that does not require separate members. For example, if the packaged food 201 is arranged so that the front sheet 1A having the steam port forming resin layer 4 is positioned on the upper side and the back sheet 1B is positioned on the lower side (FIG. 3), , the food F will be located away from the upper steam port 11 . Therefore, even if the food F contains a large amount of liquid, it is possible to prevent the liquid from leaking from the steam port 11 during or after microwave heating. Moreover, it is possible to easily fill the storage space 7 with a large-sized solid object, and to maintain the sealing strength during transportation, storage, and the like.

Hereinafter, the packaging bag etc. which implemented this invention are demonstrated more concretely.

The general laminated structure of the laminated film to be used (front sheet 1A, back sheet 1B, bottom sheet 1C) is
ONY (25)/color ink, nitrocellulose-polyamide resin/adhesive/LLDPE (40)
is. however,
base material layer 2/printing ink layer 3, steam port forming resin layer 4/adhesive layer 5/sealant layer 6,
ONY (25): biaxially oriented nylon film, thickness 25 μm,
LLDPE (40): linear low density polyethylene film, thickness 40 μm,
is.

The vapor port forming resin layer 4 has a rectangular coating shape and a thickness of 1 to 5 μm. formed in the center. At that time, a part of the gusset seal portion 9 between the printing ink layer 3 and the adhesive layer 5 in the pouched front sheet 1A (central position in the pouch width direction) is gusseted from the inside of the inner edge of the gusset seal portion 9. The steam port forming resin layer 4 was arranged so as to cross the gusset seal portion 9 up to the outer edge of the seal portion 9 .

A packaging bag 101 was produced by bag making as a standing pouch using the sheets 1A, 1B, and 1C. The pouch dimensions are (Fig. 1(A)),
X=140 mm (width), Y=180 mm (height), y1=25 mm (gusset width),
X=160 mm (width), Y=180 mm (height), y1=30 mm (gusset width),
d=10 mm (seal width of the side seal portion 8) and y2=5 mm (seal width at the center of the width direction of the gusset seal portion 9).

After forming the gusset seal portion 9 and the side seal portion 8 (FIG. 1(A)), a predetermined amount of food F is filled into the packaging bag 101 from the opening 10h, and the opening 10h is heat-sealed (top seal portion 10) was sealed (FIG. 1(B)). The packaged food 201 was set in a microwave oven in a horizontal position so that the back sheet 1B was positioned on the lower side (FIG. 3), and when microwave heating was performed, normal steaming from the steam port 11 was confirmed. did it.

1A front sheet (laminated film)
1B back sheet (laminated film)
1C bottom sheet (laminated film, gusset part)
2 base material layer 3 printing ink layer 4 vapor port forming resin layer 5 adhesive layer 6 sealant layer 7 housing space 8 side seal portion 8a notch 9 gusset seal portion 9a punch hole 10 top seal portion 10h opening 11 vapor port 12 overlapping region 101 Packaging bag 201 Packaged food F Food (contents)
V steam

Claims (6)

A standing type packaging bag for microwave heating, which is made by heat-sealing a laminated film so that a storage space for storing contents is formed inside the packaging bag,
The laminated film includes a front sheet, a back sheet facing the front sheet through the accommodation space, and a bottom sheet forming a double-fold gusset between the front sheet and the back sheet. death,
As the seal portions formed by the heat sealing, side seal portions formed by the front sheet and the back sheet, and gusset seal portions formed by the front sheet and the back sheet and the bottom sheet; has
A steam port-forming resin layer for adjusting lamination strength is formed on the front sheet so that a steam port for discharging steam generated by microwave heating of the contents from the accommodation space is formed in a part of the gusset seal portion. and on only one of said backsheets,
A packaging bag, wherein holes are formed in the bottom sheet so that the front sheet and the back sheet are heat-sealed in an overlapping region between the side seal portions and the gusset seal portions. 2. The packaging bag according to claim 1, wherein the steam port-forming resin layer is formed so as to cross the gusset seal portion from the inner side of the inner edge of the gusset seal portion to the outer edge of the gusset seal portion. . The laminated film has a laminated structure including a substrate layer, an adhesive layer, and a sealant layer, and the vapor port forming resin layer increases the lamination strength between the substrate layer and the sealant layer to 3. The packaging bag according to claim 1, wherein the height is increased and the height is decreased in a high temperature environment. The length in the width direction of the packaging bag is 130 to 160 mm, the seal width of the side seal portion is 10 mm or more, the seal width at the center of the width direction of the gusset seal portion is less than 10 mm, and the steam port forming resin 4. The packaging bag according to any one of claims 1 to 3, wherein the layer has a rectangular coating shape and is positioned at the center in the width direction of the gusset seal portion. 5. The steam vent-forming resin layer is positioned on the front sheet in a laterally placed state in which the front sheet is positioned on the upper side and the back sheet is positioned on the lower side. or the packaging bag according to item 1. A packaged food for heating in a microwave oven, comprising: the packaging bag according to any one of claims 1 to 5; A packaged food characterized by

Images