JP5751612B2 - Microwave packaging bag - Google Patents

Description

  The present invention relates to a microwave packaging bag that hermetically wraps food to be cooked in a microwave oven. More specifically, food packaging containing a large amount of juice is circulated and distributed, and the impact and the like during distribution and storage. Even if it receives, the internal juice does not leak to the outside, and the bag can not be torn or ruptured when heated in the microwave, so it can be used safely and safely, and the bag can be easily put into the microwave oven to make steamed vegetables etc. The present invention relates to a microwave packaging bag.

In recent years, microwave ovens have a variety of ingredients such as cooked processed foods, foods (hereinafter collectively referred to as “food”), and can be cooked quickly in a short time. It has become widespread. With this spread, foods cooked in a microwave oven have become various and diverse. These foods are generally distributed in a state of being sealed and packaged in plastic packaging bags, displayed in stores, and bought by general consumers. The purchased food is cooked in a microwave oven, but when heated while sealed, the internal pressure in the bag rises due to water vapor generated from the food inside, and the bag body expands. At that time, if the internal pressure exceeds a predetermined level, the packaging bag will be torn or ruptured, and the food inside will be scattered in the microwave oven, contaminating the inside of the oven and destroying the prototype of the cooked food. It will be lost.

  In the past, in order to prevent such breakage or rupture of the packaging bag, a method of cutting a part of the packaging bag in advance with a scissors or the like before heating with a microwave oven, A method of drilling a needle hole or the like in a part was adopted. However, both of these methods are cumbersome and sometimes forgotten. Therefore, recently, a packaging bag has been proposed that is designed so that when the vapor pressure in the packaging bag exceeds a certain level, the bag mouth is automatically opened to prevent tearing or bursting.

  For example, the following Patent Document 1 describes a bag produced using a gas venting functional film material. Hereinafter, the bag described in Patent Document 1 will be described with reference to FIG. 11 shows a bag described in Patent Document 1 below, FIG. 11A is a cutaway front view of the main part, and FIG. 11B is an enlarged plan view of the main part of FIG. 11A. This bag 30 includes a gas passage 31 provided with two stages of liquid stoppers 32 that are intermittently thermally welded laterally at predetermined intervals in the vertical direction, and the upper and lower liquid stoppers are displaced. A welded portion 33 that is partially welded on the gas passing zone and communicates with the exhaust hole portion 34, and a closed portion 37 that releases the internal pressure by bringing the films on both sides into close contact with each other on the welded portion. It has become a thing.

  When the internal container is heated in the microwave oven, gas is generated from the container and the pressure inside the bag is increased. Due to this pressure increase, the generated gas enters the gas flow zone 31 and passes through the exhaust hole 34 from the inner edge 36 of the nonwoven fabric 35 provided long inward and into the closed part 37 to push the film 38. Open and discharged from the exhaust opening 39 to the outside air. Further, if the contained material contains a large amount of liquid, the liquid enters the gas passage 31. The liquid that has entered the lower surface of the lower liquid stopper 32 falls downward, and Even if the liquid further rises with a strong internal pressure, it falls down by hitting the upper liquid stopper, so that leakage to the outside is prevented. In particular, since both side ends of the liquid stopper 32 are inclined downward, the liquid component hitting the liquid stopper 32 is deflected downward and blocked by a passage between the lower liquid stoppers. Since the upper liquid stopper is arranged as described above, it does not go up as it is. Therefore, according to the bag described in the following Patent Document 1, when heated in a microwave oven, only the gas is released to the outside, and the liquid component does not leak to the outside, so it can be used with confidence. is there.

  Patent Document 2 below also describes a similar packaging bag. The packaging bag described in Patent Document 2 below forms a cylindrical body by heat-sealing the back seal part in a palm seal type, and heat-sealing the openings at both ends of the cylindrical body, and a pillow pouch type. In addition, in order to adjust the internal pressure in the bag that rises when the food stored in the bag is heated together with the bag at the back seal part or at the top, bottom, left, or right edge part of the bag to a certain range An exhaust passage having a bent structure is provided.

  Furthermore, the following patent documents 3 and 4 also describe similar packaging bags. The packaging bag described in the following Patent Document 3 has a heat seal portion, and in an easily peelable packaging body filled with contents, a recess is provided on the outer edge of the heat seal portion, and the inner edge of the seal portion is straight. Further, an easily peelable packaging body is formed with an interlayer peelable film. Moreover, the packaging bag described in the following Patent Document 4 is such that, in the top seal portion, the deepest portion of the V-shaped portion is positioned closer to the contents than the inner edge portion of the heat seal portion.

  All of the packaging bags described in Patent Documents 1 to 4 have the seasoning liquid (material) and ingredients together, that is, the ingredients seasoned with the seasoning liquid (material) are packed in the bag. Have been used. However, if the ingredients seasoned with the seasoning liquid (material) are packaged in this way, the seasoning liquid (material) may soak into the ingredients excessively, and the taste of the ingredients themselves may be erased. Therefore, the following patent document 5 describes a packaging bag in which the inside of a bag is divided into two chambers, seasoning liquid (material) is packed in one chamber, ingredients are packed in the other chamber, and mixed during cooking. Yes. As shown in FIG. 12, the packaging bag 40 described in the following Patent Document 5 was an easily peelable film in which the inside of the substantially rectangular shape whose periphery was sealed was substantially parallel to any side edge of the periphery. A partition seal portion 41 is provided, the interior is divided into two chambers, and a vent 42 is formed around a part of the packaging bag.

JP-A-11-240579 (paragraphs [0005] to [0008], FIG. 1) JP 2000-327047 A (paragraphs [0034] to [0036], FIG. 1) JP 10-147371 A (paragraph [0036], FIG. 1) JP-A-8-276966 (paragraphs [0028] to [0030], FIG. 1) JP 2009-214982 (paragraph [0005], FIG. 1)

  Since the microwave oven packaging bags described in Patent Documents 1 to 4 are partially opened when the vapor pressure in the bag exceeds a certain level during cooking, the bag body is torn. However, these packaging bags have some problems due to their structure. That is, the packaging bag described in Patent Document 1 includes a gas passage having a two-stage liquid stop portion, a welded portion having an exhaust hole portion, and a closed portion having an exhaust opening portion from the inside toward the outside. However, since the opening of the exhaust opening is opened, if for some reason the internal gas and liquid juice pass through the gas passing zone and the welded portion, the liquid juice will open to the exhaust opening. In addition, there is a possibility that various germs and the like enter the inside through the opening of the exhaust opening. In addition, in the packaging bag described in Patent Document 1, a two-stage liquid stopper is provided in the gas passing zone in order to eliminate the ejection of the liquid juice. Leakage may occur, and it is necessary to provide a two-stage liquid stopper, non-woven fabric, exhaust hole, and exhaust opening in the gas flow zone, welded part, and closed part. Is cumbersome and expensive.

  Moreover, although the packaging bag described in the said patent document 2 makes the exhaust path bend | folded structure, this packaging bag also has the subject similar to the said patent document 1. FIG. Furthermore, the packaging bag described in Patent Documents 3 and 4 has a simple structure because the opening location becomes a recess or a V-shaped part, but a special delamination film must be used. There is a risk of high costs. In addition, the packaging bag described in Patent Document 5 below has a partition seal portion made of an easily peelable film, and since the material is different from the bag body, two types of materials are required, and the production is troublesome. Moreover, since the easily peelable film of the partition seal part is different in material from the bag body, it becomes a weak seal part between the bag body, and when the internal pressure in the bag becomes high, gas leakage from this part occurs simultaneously. Liquid juice may erupt.

  Furthermore, since the packaging bag described in the following Patent Document 5 has a part of the central portion of the partition seal portion as an unsealed portion, when liquid such as seasoning is put into the upper chamber, the liquid is placed in the lower chamber. May fall and be mixed into ingredients in the lower chamber. Furthermore, in the packaging bag described in Patent Document 5 below, when the internal pressure in the bag becomes high during cooking, the unsealed portion opens and the opening is enlarged. Since the seasoning enters the lower chamber through the narrow opening, the seasoning is not well dispersed in the ingredients in the lower chamber, so that the seasoning is not well mixed and the taste is biased. For example, when salt is packed in the upper chamber and green beans are packed in the lower chamber, the opening is narrow, so that the salt is difficult to disperse evenly and is not evenly attached to the surface of the green beans. In addition, after cooking, it is necessary to transfer the ingredients from the packaging bag to a dish, etc., but the ingredients are hot, and there is a danger of the transfer work, and it takes time and effort, and after washing the dishes etc. Is essential.

  The present invention was made to solve the problems of these conventional techniques, and has an object to provide a packaging bag for a microwave oven that is excellent in safety, hygiene, and productivity, and that can be used with confidence. And Specifically, the object of the present invention is excellent in safety because there is no tearing or rupture of the bag body during transportation or cooking, and there is no invasion of bacteria from outside into the bag even during distribution and storage. Another object of the present invention is to provide a packaging bag for a microwave oven that can be manufactured with ease and at low cost, is excellent in productivity, and can be used with peace of mind without leakage or ejection of liquid juice.

  In addition, another object of the present invention is to have the above object, and further can automatically reduce the internal pressure without causing a tear or rupture in a state where the bag body is self-supporting during cooking, Ingredients and seasoning liquid (material) can be packaged separately, and during cooking, the seasoning liquid (material) is widely dispersed and mixed in the ingredients, and it is easily steamed vegetables in the microwave oven together with the bag. It is in providing the packaging bag for microwave ovens which can cook etc. and can use a bag body as a simple dish as it is after cooking.

In order to solve the above-described problem, the packaging bag for a microwave oven according to the first aspect of the present invention includes a pair of first and second plastic films having a predetermined area extending a predetermined length from the bottom portion, The package having a bag mouth having a bag mouth sealing portion that is sealed after the bottom portion and both side edges connected to the bottom portion are sealed and the article to be packaged is packed on one side facing the remaining bottom portion In a microwave packaging bag consisting of a bag body for hermetically wrapping things,
The bag body is in the vicinity of the bag mouth and is raised in a state in which the bag mouth is sealed when the internal pressure of the bag body rises in order from the bag mouth toward the bottom. A gas discharge part for discharging the internal pressure to the outside, and a liquid leakage block part for blocking leakage of the liquid from the package to the gas discharge part,
The liquid leakage block portion includes a weak heat welding seal band in which the first and second plastic films are thermally welded with a predetermined width and weak sealing strength across the both side edges, and the weak heat welding seal is formed. The seal strength of the belt is weaker than the heat welding seal strength of the side edges and the bag mouth ,
The gas discharge part is formed of a continuous or discontinuous slit formed in at least one of the first and second plastic films, and the slit is recessed from the inner wall surface of the film toward the outer surface. The top part protrudes thinly outwardly, It is characterized by the above-mentioned.

  Moreover, the packaging bag for microwave ovens of a 2nd aspect is a packaging bag for microwave ovens of a 1st aspect, The said gas discharge | release part is between the location which seals the said bag mouth, and the said liquid leak block part. It is characterized by being provided across.

  Further, the microwave oven packaging bag of the third aspect is the microwave oven packaging bag of the first aspect, wherein a predetermined gap is provided between the bag mouth seal portion and the liquid leakage block portion, and the gap The gas discharge part is provided in the structure.

  Moreover, the microwave oven packaging bag according to the fourth aspect is the microwave oven packaging bag according to any one of the first to third aspects, wherein the weak heat welding seal band crosses the width or reduces the width. At least one weak welding location close to welding or non-welding is provided.

  Further, the microwave packaging bag of the fifth aspect is the microwave packaging bag of any one of the first to fourth aspects, wherein the low heat welding seal band has a low sealing strength on the bottom side of the bag body, The gas discharge part side is high.

Moreover, the microwave oven packaging bag according to the sixth aspect is the microwave oven packaging bag according to any one of the first to fifth aspects, wherein the bag body is covered between the liquid leakage block portion and the bottom portion. A partition portion for separately storing the package is provided, and the partition portion is formed of a weakly heat-sealed seal band in which the first and second plastic films are thermally welded with a predetermined width across the both side edges. The seal strength of the weak heat welding seal band is weaker than the heat welding seal strength of the side edges and the bag mouth.

Further, the microwave oven packaging bag according to the seventh aspect is the microwave oven packaging bag according to the sixth aspect, wherein the weak heat welding seal band crosses the width or does not weld or reduces the width. It is characterized in that at least one near weak welding location is provided.

Further, the microwave packaging bag according to the eighth aspect is the microwave packaging bag according to the sixth or seventh aspect, wherein the weak heat welding seal band has a low sealing strength on the bottom side of the bag body, and the gas The discharge part side is high.

In addition, the microwave packaging bag according to the ninth aspect is the microwave packaging bag according to the eighth aspect, wherein the bag body has a notch on at least one side of the both sides on the bottom side of the intermediate partition portion. It is formed.

The microwave oven packaging bag according to a tenth aspect is the microwave oven packaging bag according to any one of the first to ninth aspects, wherein the bottom portion is folded when the article to be packaged is not accommodated. It is characterized by the structure that the area is expanded to a size that can be self-supported when it is housed.

The microwave oven packaging bag according to an eleventh aspect is the microwave oven packaging bag according to any one of the first to tenth aspects, wherein the bag mouth seal portion is sealed in a wave shape so as to straddle the gas discharge portion. It is characterized by being.

Moreover, the microwave oven packaging bag of the twelfth aspect is the microwave oven packaging bag of any one of the first to eleventh aspects, wherein the bag mouth seal portion is from a portion that is thermally welded and sealed on both side edges. It is characterized by being provided wide.

The microwave oven packaging bag according to a thirteenth aspect is characterized in that, in the microwave oven packaging bag according to the twelfth aspect, at least one hole is formed in the bag mouth seal portion.

According to the microwave packaging bag of the first to fifth aspects of the present invention, the bag body is not torn or ruptured during transportation or heating, and is excellent in safety. There is no invasion of the product, it is hygienic, it can be manufactured easily and inexpensively, it is excellent in productivity, and it can be used safely without leakage of liquid juice. In particular, since the gas discharge part and the liquid leakage block part are provided separately in the vicinity of the bag mouth, each part can exhibit its function. That is, the liquid leakage block portion can block the leakage of the liquid in the bag body, and the gas discharge portion can release the increased internal pressure to the outside when the pressure in the bag body rises above a predetermined value. In addition, these gas discharge part and liquid leak block part are provided in the liquid leak block part inside the bag body because the former is located near the bag mouth and the latter is located behind the gas discharge part. The leak block portion can be easily formed as having each function. In particular, the formation of the gas discharge part is facilitated.

Moreover, according to the packaging bag for microwave ovens of the sixth to tenth aspects of the present invention, the internal pressure can be automatically reduced without causing tearing or rupture in a state where the bag body is self-supporting during cooking, Moreover, the ingredients and the seasoning liquid (material) can be separated and packaged so that the seasoning liquid (material) is widely dispersed and mixed in the ingredients at the time of cooking. It can be used as a simple dish.

In addition, according to the microwave packaging bag of the eleventh aspect of the present invention, the ratio of the seal part to be thermally welded of the bag mouth and the gas discharge part is increased, and the bag is generated more efficiently in the bag. The internal pressure can be released.

Moreover, according to the microwave packaging bag of the twelfth aspect of the present invention, the bag mouth portion can be provided with a portion that allows the user to grasp the packaging bag heated in the microwave oven with bare hands, The user can safely remove it from the microwave and carry it safely.

In addition, according to the microwave packaging bag of the thirteenth aspect of the present invention, the user can grip the opening through a finger or the like, and can insert chopsticks or the like. The packaged bag can be taken out and carried.

1 shows a microwave packaging bag according to Embodiment 1 of the present invention, FIG. 1A is a front view, FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A, and FIG. 1C is a cross-sectional view taken along line IC-IC in FIG. It is sectional drawing. 2 shows a liquid leakage block part in the packaging bag of FIG. 1, FIG. 2A is a front view of the liquid leakage block part, FIG. 2B is a graph of the degree of joining of the liquid leakage block part, and FIGS. 2C to 2G are liquids of FIG. It is a front view of the modification of a leak block part. FIG. 3 is a cross-sectional view illustrating the operation of the liquid leakage block portion of the packaging bag of FIG. 4 shows the gas permeation part of FIG. 1, FIG. 4A is an enlarged view of the IVA portion of FIG. 1A, and FIG. 4B is a cross-sectional view taken along line IVB-IVB of FIG. 4A. 5A is a schematic view of a slit forming apparatus for forming the gas permeable portion (slit) of FIGS. 1 and 4, FIG. 5B is an enlarged view of a VB portion of FIG. 5A, and FIG. 5C is an enlarged view of a VC portion of FIG. is there. 6 is a diagram for explaining the gas permeation action of the slit of FIG. 1, FIG. 6A is a cross-sectional view of the slit, FIG. 6B is a cross-sectional view of the slit shape at the time of gas permeation, and FIG. It is sectional drawing of a slit shape. FIG. 7 is a front view of a modification of the microwave packaging bag according to the first embodiment. 8 shows a packaging bag for a microwave oven according to Embodiment 2 of the present invention, FIG. 8A is a front view, and FIG. 8B is a cross-sectional view taken along the line VIIIB-VIIIB of FIG. 8A. FIG. 9 is a front view of a microwave packaging bag according to Modification 1 of the present invention. FIG. 10 is a front view of a microwave oven packaging bag according to Modification 2 of the present invention. FIG. 11 shows a prior art bag, FIG. 11A is a cutaway front view of the main part of the bag, and an enlarged plan view of the main part of FIG. 11B. FIG. 12 is a plan view of another prior art bag.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment shown below exemplifies a microwave packaging bag for embodying the technical idea of the present invention, and is not intended to specify the present invention. The present invention can be equally applied to other embodiments included in the scope.

[Embodiment 1]
With reference to FIG. 1, the whole structure of the packaging bag for microwave ovens concerning Embodiment 1 of this invention is demonstrated. 1 shows a microwave packaging bag according to Embodiment 1 of the present invention, FIG. 1A is a front view, FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A, and FIG. 1C is an IC-IC in FIG. It is sectional drawing of a line.

  A microwave packaging bag (hereinafter referred to as a packaging bag) 10 according to Embodiment 1 of the present invention, as shown in FIG. The two sides of the width direction are aligned, and both sides are joined (heat-sealed seal), and the other side is opened and the bottom is used as a bag mouth. In the vicinity of the opening, a bag mouth seal portion 11c, a gas discharge portion 12L, and a liquid leakage block portion 14 are provided in this order from the bag mouth to the bottom. That is, the packaging bag 10 has a predetermined width and length, a bottom 10a that can be enlarged to a relatively large area, and a pair of opposing ends that are extended a predetermined length upward from both bottom side edges in the longitudinal direction of the bottom. Films, front and back films 10b and 10c, respectively, front and back films 10b and 10c, side heat seal portions 11a and 11b in which both side edges of the front and back films 10b and 10c are heat-welded and sealed with a predetermined width W1, and upper ends The bag mouth seal portion 11c that is heat-sealed and sealed with a width of W2 after the package is opened as a bag mouth and the packaged article is stored, and when the internal pressure rises above a predetermined level adjacent to the bag mouth seal portion 11c There is a gas discharge part 12L for releasing the internal pressure to the outside, and a liquid leakage block part 14 for preventing leakage of the liquid contained in the packaged object adjacent to the gas discharge part, and the packaged article is stored inside Size Consists bag member space S is formed, it is made of a plastic film.

  The packaging bag 10 is a rectangular bag body having a width W and a length L. And the gas discharge | release part 12L consists of the several slit 12, and these slits 12 are formed ranging over the bag mouth seal | sticker part 11c and the liquid leak block part 14. FIG. The liquid leakage block portion 14 is provided at a position adjacent to the bag mouth seal portion 11c. If there is a liquid leakage block portion 14 at this position, the liquid leakage block portion 14 is at a high position in a state where the bag body is self-supporting, so that the internal volume of the bag body is not reduced and it is difficult to be immersed in the juice. Due to the increase in internal pressure in the bag, it is peeled off quickly. Of course, no liquid leaks even if the bag body is turned sideways. The bag is made of a single plastic film, but may be made using a plurality of different films. Moreover, it is preferable to provide a notch 13 on at least one side of the side heat seal portions 11a and 11b.

  This plastic film consists of polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyamide (PA), laminated film with polyethylene terephthalate (PET) on the front side and polyethylene (PE) on the front side, and polyamide (PA) on the front side A laminated film having polyethylene (PE) on the back side and a laminated film of polyethylene (PE) and polypropylene (PP) are used. This polypropylene may be either stretched (OPP) or non-stretched (CPP). The total thickness is 15 to 100 μm.

  The bottom portion 10a is folded inward, and when the article to be packaged is stored in the internal space S, the bottom portion 10a has a shape in which the folded portion is enlarged, for example, a gusset bag (folded bottom portion 10a ′), It is a so-called standing pouch.

  The front and back films 10b and 10c are also plastic film front and back faces 10b1, 10c1 and 10b2, 10c2. Although the films 10b and 10c are front and back films, any of them may be front and back when using a packaging bag. In addition, one of the front and back films 10b and 10c is expressed as a first or second plastic film in the claims.

  As shown in FIG. 1, the packaging bag 10 is joined to the outer peripheral side edge and the bag mouth by thermal welding with a predetermined width W1 to form side heat seal portions 11a and 11b and a bag mouth seal portion 11c. The side heat seal portions 11a, 11b and the bag mouth seal portion 11c have a bonding strength, so-called seal strength, which is higher than that of the liquid leakage block portion 14 by heat welding and sealing. This thermal welding sealing condition is performed by setting the welding temperature relatively high, for example, 120 ° C., and applying the predetermined pressing force for a period of time, for example, several seconds. Under these conditions, when the side heat seal portions 11a, 11b and the bag mouth seal portion 11c are heat-sealed and sealed, the bonding becomes firm, even if the packaged item is heavy or subjected to impact such as transportation, There is no peeling from these seals. As a result, the side heat seal portions 11a and 11b and the bag mouth seal portion 11c are not peeled off and the contents do not pop out.

The liquid leakage block unit 14 will be described with reference to FIGS. 2 shows a liquid leakage block portion in the packaging bag of FIG. 1, FIG. 2A is a front view of the liquid leakage block portion, FIG. 2B is a graph of the degree of joining of the liquid leakage block portion, and FIGS. 2C to 2G are FIG. FIG. 3 is a cross-sectional view for explaining the operation of the liquid leakage block portion of the packaging bag of FIG. 1.
It is.

  As shown in FIG. 1A and FIG. 2A, the liquid leakage block portion 14 has a predetermined width, for example, a band shape of several millimeters to several tens of millimeters, and a heat welding seal band that connects the heat seal portions 11a and 11b on both sides. Form with. The seal strength of the heat-welded seal band is a heat-welded seal that is weaker than the side heat seal portions 11a and 11b and the bag mouth seal portion 11c as described above. This weak heat welding seal band has a welding temperature lower than the welding temperature 120 ° C. of the side heat seal portions 11a and 11b and the bag mouth seal portion 11c, for example, 100 to 110 ° C., and a time of 0.3 to 0.5, for example. Apply a given pressure in seconds. This heat welding condition is lower than the welding temperature of the side heat seal portions 11a and 11b and the bag mouth seal portion 11c and the time is also short. According to this sealing method, it is possible to easily perform a predetermined function by adjusting the welding temperature or the pressing force as described later, without using a special film material, for example, a laminated film provided with an easily peelable layer. A seal with

  If the sealing strength of the liquid leakage block part 14 is weakly sealed as compared with the side heat seal parts 11a and 11b and the bag mouth seal part 11c, the liquid leakage is prevented in the packaged state of the package, while the internal pressure is reduced. If it exceeds a predetermined level, it peels easily and the gas exceeding the predetermined level is released from the gas discharge part, so that it is possible to prevent tearing or bursting.

  The weak heat welding seal band constituting the liquid leakage block portion 14 has substantially uniform overall seal strength, but the seal strength may be partially changed. For example, it is preferable to make the side close to the gas discharge part 12L strong and weaken as the distance from the gas discharge part increases. That is, as shown in FIG. 2B, the seal strength is such that the side b close to the gas discharge portion 12L is strong, weakens as it is separated from the gas discharge portion, and the side a farthest from the gas discharge portion becomes weakest. When the seal strength is changed in this way, when the pressure in the bag rises, the peeling starts from the inner side “a” of the bag body as the pressure rises, and the peeling phenomenon smoothly spreads to the gas discharge part 12L side “b”. It migrates and peels off. As a result, liquid leakage is prevented during transportation, storage, etc., and when the water vapor pressure generated from the packaged food exceeds a predetermined level during cooking, it peels more easily and the internal pressure is released from the gas discharge section. As a result, tearing and rupture can be prevented.

  The seal strength is adjusted by adjusting the pressure applied under the above-mentioned heat welding seal condition, for example, a strong pressing pressure on the gas discharge portion 12L side, and a heat welding seal having a shape in which the pressing pressure decreases with increasing distance from the gas discharge portion. Use the bar. As the heat welding seal bar, a pressing surface whose inclined surface is inclined at a predetermined angle or a stepped shape is used. Note that this bonding may be performed by other bonding means, such as gluing, instead of the heat welding seal.

  With reference to FIG. 3, the operation of the liquid leakage block portion will be described. Since this packaging bag 10 generates little or no water vapor from a packaged object (not shown) before non-heating cooking, the liquid leakage block portion 14 maintains a joined state ( (See FIG. 3A). When cooking starts and water vapor is generated from the package, the pressure in the bag rises and the bag body expands (see FIG. 3B). In this state, the pressure in the bag is low and the liquid leakage block part 14 is not peeled off. When heated and the pressure inside the bag exceeds a predetermined level, the heat welded portion of the liquid leakage block portion 14 begins to peel off. At this time, as shown in FIG. 2B, the sealing strength of the liquid leakage block portion 14 is stronger on the side b close to the gas discharge portion 12L, weaker as it is away from the gas discharge portion 12L, and the side a farthest from the gas discharge portion is set. 3C, as shown in FIG. 3C, the inner side of the bag body, that is, the side a farthest from the gas discharge portion 12L starts to peel off quickly following the increase in the pressure inside the bag, and further, As it rises, this peeling speed is accelerated and peeled (see FIG. 3D). Furthermore, when the pressure in the bag rises, the heat-welded part of the liquid leakage block part 14 is completely peeled off. As a result, the water vapor (gas) that has risen inside is discharged from the gas discharge portion (see FIG. 3E). At the time of the gas discharge, the bag mouth seal portion is firmly sealed, so that the seal portion does not open, and only the water vapor whose pressure has increased is ejected from the gas discharge portion.

  As shown in FIG. 2A, the weak heat-welding seal band constituting the liquid leakage block portion 14 is formed by a heat-welding pattern in which the entire surface of a predetermined width is heat-welded and sealed, but is not limited thereto. However, the thermal welding pattern may be variously changed. 2C to 2G show modified examples of the liquid leakage block unit. 2C, FIG. 2D and FIG. 2F have liquid leakage block portions 14A, 14B and 14D having predetermined shapes of non-welded portions, that is, slit shapes, triangular shapes and substantially S-shapes, in the predetermined positions of the heat welding pattern of FIG. 2A. A non-welded part is provided. According to these liquid leakage block portions 14A, 14B, and 14D, the slits, triangles, and substantially S-shaped non-welded portions serve as passages to facilitate gas passage. That is, in the liquid leakage block portion having these weak heat welding patterns, when the internal pressure in the bag rises during cooking, the raised gas first reaches the gas discharge portion through the passage of the above shape first. When the internal pressure further increases, the heat welded portion in the vicinity of the passage is peeled off, and the pressurized gas reaches the gas discharge portion.

  Note that slits, triangles, and substantially S-shaped attachment points may be replaced with non-welding, and weak seals close to non-welding may be used. In the following description, the liquid leakage block portions 14 and 14A to 14E may be referred to as weak heat welding pattern portions 14 and 14A to 14E. Moreover, the weak heat welding pattern part 14C, 14E of FIG. 2E and FIG. 2F makes a semicircular notch-like non-thermal welding location and a heat welding part corrugated. As shown in FIG. 2B, the sealing strength may be increased or decreased in the heat welding patterns of these liquid leakage block portions 14 </ b> A to 14 </ b> E. According to the liquid leakage block portion having these weak heat welding patterns, the action of FIG. 3 can be adjusted more finely.

  The gas discharge part 12L is demonstrated with reference to FIGS. 4 shows the gas permeation section of FIG. 1, FIG. 4A is an enlarged view of the IVA portion of FIG. 1A, and FIG. 4B is a cross-sectional view taken along line IVB-IVB of FIG. 4A.

  As shown in FIG. 1A, the gas discharge part 12L is formed on the film surface by a slit group including a plurality of slits 12 having a high gas permeability from one direction and a low gas permeability from the opposite direction. In the following description, the gas discharge part 12L is also referred to as a slit group 12L. Since this slit group 12L should just be formed in at least any one of the front and back films 10b and 10c, it demonstrates in this embodiment what was provided in the front film 10b part. Although the above-mentioned film is used, the thickness is preferably a predetermined thickness, for example, in the range of 15 to 100 μm in consideration of slit formation. If the thickness is less than 15 μm, it is difficult to form slits and sufficient strength may not be obtained. Moreover, when it exceeds 100 micrometers or more, a process will become difficult. Therefore, the thickness of the film material is appropriately selected depending on the kind of film resin, the use, and the like within these ranges.

  The slit group 12L is formed by arranging a plurality of slits 12 having a predetermined length in the film portion 10b at substantially equal intervals or non-uniform intervals, and these slits have the same configuration. As shown in FIG. 4B, the slit 12 is configured by a concave portion in which the bottom portion bulges from the other surface by indenting a predetermined depth from one surface to the other surface in the width direction of the film 10 b. Yes. That is, the recess is formed such that the thickness gradually decreases from the upper opening toward the bottom, and the bottom is formed to be the thinnest.

  The slit 12 is a non-through hole groove made of a narrow groove, and as shown in FIG. 4B, the wall thickness gradually swells from the upper opening groove 12a toward the bottom portion, and the bottom portion is expanded. The bottom surface 12c is swelled outward from the other surface, and the bottom 12c is thinnest, so that the cross-sectional shape is substantially U-shaped. Specifically, as shown in FIG. 4A and FIG. 4B, it has a width length s1, a length s2, and a predetermined depth. The width, length, and depth are not particularly limited, but the width is preferably 100 to 500 μm and the length is preferably 1.2 to 2.6 mm. The depth is preferably 1.2 to 2.2 times the film thickness as measured from the film surface. Furthermore, it is preferable that the thinnest wall thickness of the bottom 12c is 3 μm to 70 μm. Moreover, although the space | interval between the adjacent slits of the slit group 12L is not specifically limited, About 1.5-3.0 mm is preferable. Therefore, this slit is appropriately selected depending on the type and use of the film resin.

  The slit 12 has a substantially U-shaped cross-section, but is not limited to this, and may have another shape, for example, a V-shaped cross-section or other shapes. In the slit group 12L, a plurality of slits having a predetermined length are arranged discontinuously, but may be made continuous. Furthermore, you may provide in arbitrary places not only in the width direction. The slit and the slit group can adjust the gas permeation amount by changing the shape and the thickness of the bottom. In place of the slit, a recessed hole may be used.

  Next, a method for forming a slit will be described with reference to FIG. 5 shows a slit forming apparatus, FIG. 5A is a schematic view of the slit forming apparatus for forming the gas permeable portion (slit) of FIGS. 1 and 4, and FIG. 5B is an enlarged view of the VB portion of FIG. 5A. 5C is an enlarged view of a VC portion in FIG. 5B.

  As shown in FIG. 5A, the processing device 15 includes a pretreatment device 16 that pretreats a long film, and a slit forming device 17 that forms a slit group 12L on the film. Although the slit group 12L is formed on the front film 10b of a long film, hereinafter, the film forming the slit group 12L is represented by 10f. The pretreatment device 16 is a temperature adjustment device that treats the film so that the temperature exceeds the glass transition point of the film material and is lower than the melting point. The temperature adjustment in the pretreatment device 16 is important for forming a slit in the film 10f. The film 10f is made of the above-described plastic film, that is, a polymer material. This polymer material is in a state where a crystalline portion and an amorphous portion coexist at a low temperature, and is in a glass state with a small molecular motion. . When heated from this state and the temperature rises, the molecular motion increases to become a rubber state, and when further heated, it becomes a molten state. The boundary from the glass state to the rubber state is the glass transition point, and the boundary from the rubber state to the molten state is the melting point. Therefore, by heating the film material to a temperature exceeding the glass transition point and softening, the slit can be rolled and the bottom can be rolled thinnest.

  Further, at this temperature, rolling can be performed while maintaining gas barrier properties, so that a thin slit can be formed without impairing the properties of the film. In addition, a slit having no pinholes can be formed. The glass transition point and melting point vary depending on the material of the film. When PP is used as a film material, the PP has a glass transition point of minus 18 ° C. and a melting point of 163 ° C., so the temperature is adjusted to 40 to 120 ° C., which is higher than normal temperature. Similarly, since PET has a glass transition point of 81 ° C. and a melting point of 264 ° C., the temperature is about 85 to 200 ° C., while LDPE has a glass transition point of −125 ° C. and a melting point of 115 ° C. Since it is ° C., the temperature is adjusted to 20 to 100 ° C. higher than normal temperature. Moreover, in the multilayer structure film which laminated PET and LDPE, it adjusts to the range of temperature 85-100 degreeC.

  PP and PE already exceed the glass transition point at room temperature, but the melting point is 120 ° C., so the degree of processing is adjusted within that range. Even with the same film material, since the softness of the film varies depending on the temperature in the range exceeding the glass transition point and less than the melting point, the slit can be easily formed by raising the temperature even with light pressing in the next slit forming apparatus.

  The slit forming device 17 includes a disc-shaped pressing roll 17A in which a plurality of slit forming teeth 18 are arranged at predetermined intervals around the outer periphery, and a receiving roll 17B that sandwiches the film 10f between the pressing rolls. have. The pressing roll 17A is formed of a metallic disk-shaped gear having a predetermined diameter, thickness, and hardness. The pressing roll 17A rotates around a shaft 17a, and forms a slit 12 so that a long film 10f is moved in the X direction. To send. As shown in FIG. 5B, the plurality of slit forming teeth 18 are substantially saw-toothed teeth having a predetermined pitch p and a height h. The slit forming teeth 18 have a predetermined R1 on the bottom 18a and an R2 R on the top tip 18b. The pitch p is not particularly limited, but is 2.0124 mm and the height h is 2.0 mm. R2 is in the range of 0.05 to 1.0 mm, and even in this range, 0.1 to 0.2 mm is preferable. If the thickness is 0.1 mm or less, the film material is damaged and the pinhole is easily opened when mechanical wear is severe. If it is 1.0 mm or more, the pressing area can be widened. R1 is 0.5 mm. Note that the teeth may be continuous with a pitch of zero. In this case, the width is narrowed to ensure a sufficient pressing force. That is, when the number of teeth is increased, the number of teeth increases, and as a result, the unit area increases and the overall pressing force decreases. Therefore, the desired pressing force is ensured by reducing the width and reducing the area.

  The pressing roll 17A is a disc-shaped gear, but may be a roll, that is, a cylindrical body or a cylindrical body. By making it into a roll shape, a long slit and a continuous slit can be formed. Although the gear provided with the slit forming teeth is not particularly limited, for example, it is preferable to use a gear provided with spur teeth. The flat teeth are rectangular in a plan view, have a length of 1.5 to 2.6 mm, a width of 30 to 500 μm, and 1.2 to 2.4 times the film thickness in an elevation view. Use one. When this flat tooth is used, if the total thickness of the film material is 50 μm, it is 60 to 120 μm from the bottom of the film material to the top of the mountain. This degree is determined by the amount of gas to be permeated.

  Similarly to the pressing roll 17A, the receiving roll 17B receives pressure when the slit 12 is formed in the film 10f by the pressing roll 17A while rotating about the shaft 17b, and sends the film 10f in the X direction. The pressure roll 17A has a hardness of 60 to 63 and is formed of a metal material having a hardness lower than that of the receiving roll 17B. The receiving roll 17B is formed of a metallic cylindrical body or cylindrical body having a predetermined diameter and hardness, and the hardness is set to 63 to 67. The pressing roll 17A is not scraped even if it is processed by, for example, 1 million m when the receiving roll 17B is pressed by the pressing roll 17A by making the hardness lower than that of the roll 17B.

  The processing device 15 processes the long film 10f to a temperature exceeding the glass transition point by the pre-processing device 16 and sends it to the slit forming device 17, and the film having a predetermined temperature by the slit forming device 17 is pressed by the press roll. The film material is rolled between 17A and the receiving roll 17B and a predetermined pressing force is applied to the pressing roll 17A to form a slit (see FIG. 5C). This slit is formed by adjusting the pretreatment temperature of the material and the pressing force of the pressing roll according to the type and thickness of the film material. When the bottom of the slit is thinned, the gas permeability is increased by the thinned portion, but the strength is decreased. The degree is determined by adjusting at least one of the pretreatment temperature and the pressing force. For example, if the glass transition point of the film material is 50 ° C. and the melting point is 125 ° C., if the pretreatment temperature is 60 ° C. or 120 ° C., the latter is softer than the former, while the pressing force is lower than the former. It can be formed with a light pressing force. This pressing degree is adjusted, for example, between 0 and 0.5 MPa. About 0.2 MPa is preferable. In addition, 0.5 Mpa is about 5 kg / square centimeter.

  With reference to FIG. 6, the gas (gas) permeation | transmission effect | action of a slit is demonstrated. 6 is a diagram for explaining the gas permeation action of the slit of FIG. 1. FIG. 6A is a sectional view of the slit, FIG. 6B is a sectional view of the slit shape during gas permeation, and FIG. It is sectional drawing of the slit shape at the time of permeation | transmission.

  When an internal pressure is applied to the slit 12 from the direction of the arrow A, as shown in FIG. 6B, the bottom of the slit is stretched and expanded by the pressure and expands into a balloon shape, and the thickness is further reduced. Gas passes through. The slit 12 has gas permeation that is easier to adjust the amount of permeation than the prior art and has other effects. Specifically, since the thickness of the bottom of the conventional technology is almost uniform, it cannot be made as thin as possible, and the current processing technology has a limit of about 8 μm. Since the thickness can be reduced to almost the limit (about 3.0 μm), the amount of permeation can be easily adjusted.

  Further, as shown in FIG. 6C, when pressure is applied from the reverse direction (arrow A ′ direction), the bottom 12c1 of the slit is pressed in the reverse direction, but the gas permeation amount is significantly smaller than that in the direction of FIG. 8B. Become. This phenomenon has been confirmed by experiments. When the transmission amount is 10 from the opening side, the transmission amount from the reverse direction is about 1-2. As a result, the film 10f has good gas permeability from one direction and is difficult to perform gas permeability from the opposite direction, so that it is possible to prevent intrusion of unnecessary substances such as bacteria.

  Since the packaging bag 10 demonstrated above provided the gas discharge part and the liquid leak block part separately in the vicinity of the bag mouth, each part can exhibit each function. That is, the liquid leakage block part can block the liquid in the bag body from leaking to the outside, and the gas discharge part is not immersed in the liquid when the pressure in the bag body is low, and when it rises above a predetermined value This increased internal pressure can be released to the outside. In addition, these gas discharge part and liquid leak block part are provided in the liquid leak block part inside the bag body because the former is located near the bag mouth and the latter is located behind the gas discharge part. The leak block portion can be easily formed as having each function. In particular, the formation of the gas discharge part is facilitated. As a result, this packaging bag has excellent safety with no tearing or rupture of the bag body during transportation or heating, and excellent hygiene with no invasion of bacteria from outside into the bag during distribution and storage, In addition, it can be manufactured easily and inexpensively, has excellent productivity, and can be used safely without leakage of liquid juice.

  The packaging bag 10 has the gas discharge portion and the liquid leakage block portion adjacent to each other, that is, a plurality of slits constituting the gas discharge portion 12L are formed across the bag mouth seal portion 11c and the liquid leakage block portion 14. However, like the packaging bag 10A, a predetermined gap L0 may be provided between the location where the bag mouth is sealed and the liquid leakage block part, and the gas discharge part may be provided in this gap (see FIG. 7). ). According to this packaging bag 10A, gas can be discharged between the gaps L0. In particular, when the weak welding patterns 14A, 14B, and 14D shown in FIG. 2 are used for the liquid leakage block portion, the gas is released by inflating between the gaps L0, and the discharge becomes easy.

[Embodiment 2]
With reference to FIG. 8, the packaging bag for microwave ovens concerning Embodiment 2 of this invention is demonstrated. 8 shows a microwave packaging bag according to Embodiment 2 of the present invention, FIG. 8A is a front view, and FIG. 8B is a sectional view taken along line VIIIB-VIIIB in FIG. 8A. The microwave oven packaging bag 10B according to the second embodiment of the present invention is partitioned by a partition seal portion so that the inside of the bag body of the packaging bag 10, 10A according to the first embodiment is vertically formed with a predetermined size chamber. It is a thing. Therefore, portions common to both are denoted by the same reference numerals, and redundant description will be omitted, and different configurations will be described in detail.

  The packaging bag 10B is formed by dividing the inside of the packaging bag 10, 10A, that is, between the bottom 10a of the bag and the liquid leakage block portion 14 by a partition seal portion 19, and using the partition seal portion as a boundary. An upper chamber S1 is formed above, and a lower chamber S2 is formed below. The size (volume) of the upper and lower chambers S1, S2 is determined by the type and size of the articles to be packaged stored in the respective chambers. For example, when a foodstuff is put into the lower chamber S2 and a seasoning seasoning this foodstuff is put into the upper chamber S1, the type and amount of the foodstuff and the amount of seasoning necessary for this foodstuff are taken into consideration. Moreover, the partition seal | sticker part 19 is joined by the heat welding pattern of the liquid leak block part 14 used by the packaging bags 10 and 10A. These thermal welding patterns are selected by selecting a thermal welding pattern 14, 14C, 14E (see FIG. 2A, FIG. 2E, FIG. 2E) without a passage when a liquid material is put into the upper chamber S1. In the case of putting in, the heat welding patterns 14A, 14B, and 14D having passages (see FIGS. 2C, 2D, and 2F) are selected.

  Moreover, even in these heat welding patterns, when partition sealing is performed with a seal strength changed, the internal pressure of the lower chamber increases, and the seal is peeled off at a predetermined level, for example, when the food in the lower chamber is cooked. The seasoning in the upper chamber is mixed and dropped on the substantially entire surface without being biased toward the food in the lower chamber. For example, when asparagus, potatoes, green soybeans, etc. are stored in the lower chamber S2, a seasoning that seasons these ingredients, such as salt, is put in the upper chamber S1 and heated in a microwave oven in a short time. Moreover, the salt is sprinkled on the whole and you can cook deliciously. That is, steamed vegetables etc. can be easily made by putting the whole packaging bag in a microwave oven. In particular, by making the welding force of the partition seal part 19 lower than the welding force of the liquid leakage block part 14, the internal pressure increases after being applied to the microwave oven, so that the partition seal part 19 is first peeled off and seasoned with the ingredients. Since the internal pressure is further increased by further heating in the mixed state, the liquid leakage block part 14 is peeled off, and the internal pressure can be released from the gas discharge part 12L. It becomes possible to cook efficiently. In addition, although the welding force of the partition seal | sticker part 14 at this time peels with the internal pressure by the heating in a microwave oven, it is preferable to adjust so that it may not peel with the load added by transportation etc. Furthermore, since the bag body bottom portion 10a has a large area and can be erected, the bag body can be used as a simple dish by tearing from the notch 13 ′. The weak heat welding seal band is characterized in that the seal strength on the bottom side of the bag body is low and the gas discharge side is high.

[Modification 1]
With reference to FIG. 9, the packaging bag for microwave ovens which concerns on the modification 1 of this invention is demonstrated. In addition, FIG. 9 is a front view of the packaging bag for microwave ovens which concerns on the modification 1 of this invention. The microwave packaging bag 10C according to the first modified example of the present invention is such that the portion to be heat-sealed and sealed at the bag mouth of the packaging body 10, 10A, and 10B of Embodiments 1 and 2 straddles the gas discharge portion. It is formed so as to be sealed in a wave shape. Therefore, common portions are denoted by the same reference numerals, and redundant description is omitted, and different configurations are described in detail.

  As shown in FIG. 9, the portion to be heat-sealed and sealed of the bag mouth seal portion 10c ′ of the packaging bag 10C is formed and sealed so as to have a wave shape. By adopting such a configuration, the ratio of the seal portion of the bag mouth seal portion 10c ′ that is thermally welded to the gas discharge portion 12L increases, and the internal pressure generated in the bag body is discharged more efficiently. Will be able to.

[Modification 2]
With reference to FIG. 10, the packaging bag for microwave ovens which concerns on the modification 2 of this invention is demonstrated. In addition, FIG. 10 is a front view of the packaging bag for microwave ovens which concerns on the modification 2 of this invention. The microwave oven packaging bag 10D according to the second modified example of the present invention is such that the portions to be heat-sealed and sealed at the bag mouths of the packaging bags 10, 10A to 10C of the first and second embodiments and the modified example 1 are on both sides. It is provided wider than the portion of the edge that is heat-sealed and sealed. Therefore, common portions are denoted by the same reference numerals, and redundant description is omitted, and different configurations are described in detail.

  As shown in FIG. 10, the width W2 ′ of the portion to be heat welded and sealed of the bag mouth seal portion 10c ″ of the packaging bag 10D is the width length of the portions to be heat welded and sealed of the side heat seal portions 11a and 11b. It is wider than W1. By adopting such a configuration, the bag mouth seal portion 10c ″ can be provided with a portion that allows the user to grasp the packaging bag 10D heated by the microwave oven with bare hands. It can be taken out of the microwave and carried again. In addition, by forming an opening 20 in the wide bag mouth seal portion 10c '', a user can hold the opening 20 with a finger or the like, or insert chopsticks or the like. Therefore, the heated packaging bag can be taken out and carried more safely. In addition, in FIG. 10, although demonstrated using the packaging bag 10 which concerns on Embodiment 1, it is not restricted to this, The packaging bag 10A which concerns on Embodiment 1, the packaging bag 10B which concerns on Embodiment 2, and the packaging which concerns on the modification 1 The same can be applied to the bag 10C.

10, 10A-10D Packaging bags for microwave ovens (packaging bags)
10a Bottom portion 10b, 10c Front and back films (first and second plastic films)
11a, 11b Side heat seal part 11c-11c '' Bag mouth seal part 12L Gas discharge part 12 Slit 13, 13 'Notch 14, 14A-14E Liquid leak block part (weak heat welding seal zone)
DESCRIPTION OF SYMBOLS 15 Processing apparatus 16 Pre-processing apparatus 17 Slit formation apparatus 18 Slit tooth | gear 19 Partition seal part 20 Open hole S Space S1 Upper chamber S2 Lower chamber

Claims (13)

A pair of first and second plastic films extending a predetermined length from the bottom and having a predetermined area are overlaid, the bottom and both side edges connected to the bottom are sealed, and face the remaining bottom. In a microwave oven packaging bag consisting of a bag body that hermetically wraps a packaged article having a bag mouth sealing part sealed after packing the packaged article on one side,
The bag body is in the vicinity of the bag mouth and is raised in a state in which the bag mouth is sealed when the internal pressure of the bag body rises in order from the bag mouth toward the bottom. A gas discharge part for discharging the internal pressure to the outside, and a liquid leakage block part for blocking leakage of the liquid from the package to the gas discharge part,
The liquid leakage block portion includes a weak heat welding seal band in which the first and second plastic films are thermally welded with a predetermined width and weak sealing strength across the both side edges, and the weak heat welding seal is formed. The seal strength of the belt is weaker than the heat welding seal strength of the side edges and the bag mouth ,
The gas discharge part is formed of a continuous or discontinuous slit formed in at least one of the first and second plastic films, and the slit is recessed from the inner wall surface of the film toward the outer surface. A packaging bag for a microwave oven, characterized in that the top part protrudes thinly outward .   The packaging bag for a microwave oven according to claim 1, wherein the gas discharge part is provided across a portion where the bag mouth is sealed and the liquid leakage block part.   The microwave oven packaging bag according to claim 1, wherein a predetermined gap is provided between the bag mouth seal part and the liquid leakage block part, and the gas discharge part is provided in the gap. .   The at least one weak welding location which crosses the said width | variety or narrows this width | variety, or the weak welding location close | similar to this non-welding is provided in the said weak heat welding seal | sticker band. The packaging bag for microwave ovens of description.   The microwave oven packaging bag according to any one of claims 1 to 4, wherein the weak heat-welded seal band has a seal strength that is low on the bottom side of the bag body and high on the gas discharge side. The bag body is provided with a partition part for separately storing the packaged object between the liquid leakage block part and the bottom part, and the partition part is configured to attach the first and second plastic films to the both sides. It consists of a weakly welded seal band that is heat welded with a predetermined width across the edges, and the seal strength of the weakly welded seal band is weaker than the heat welded seal strength of the side edges and the bag mouth. The packaging bag for microwave ovens in any one of Claims 1-5 characterized by the above-mentioned. 7. The microwave oven according to claim 6 , wherein the weak heat welding seal band is provided with at least one non-welding portion that crosses the width or narrows the width or a weak welding portion close to the non-welding. 8. Packaging bag. The packaging bag for a microwave oven according to claim 6 or 7 , wherein the weak heat welding seal band has a low sealing strength on the bottom side of the bag body and a high level on the gas discharge portion side. The said bag body is a packaging bag for microwave ovens of Claim 8 by which the notch is formed in at least one side of the said both sides at the said bottom part side of the said intermediate partition part. The bottom portion is folded during non-receiving of the packaged articles, according to claim 1 to 9, characterized in that there is a structure in which the area sized to self is expanded when it is accommodated in the material to be packaged The packaging bag for microwave ovens in any one of. The packaging bag for a microwave oven according to any one of claims 1 to 10 , wherein the bag mouth seal portion is sealed in a wave shape so as to straddle the gas discharge portion. The packaging bag for a microwave oven according to any one of claims 1 to 11 , wherein the bag mouth seal portion is provided wider than a portion to be heat-sealed and sealed on both side edges. The packaging bag for a microwave oven according to claim 12 , wherein at least one opening is formed in the bag mouth seal portion.

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