JP2010100326A - Packaging bag for microwave heating and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packaging bag for microwave heating and its manufacturing method for preventing the packaging bag itself from falling down when it is heated and expanded. <P>SOLUTION: This packaging bag 1 for microwave heating made of rectangular resin films and formed by sealing both end sides 3 includes a steam releasing part 13 for releasing steam by separating the sealed part by inner pressure when it is microwave-heated, a bottom surface facing the part 13 and a pair of side seal parts 12 provided along the longitudinal direction on both end sides in the width direction of the bottom surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a bag for hermetically storing contents such as food to be cooked in a microwave oven, and more particularly, an electronic device provided with a vapor venting section that escapes steam and prevents bursting when the internal pressure rises due to heating of the microwave oven. The present invention relates to a packaging bag for range heating and a method for producing the same.

  Contents such as cooked or semi-cooked food stored in a sealed state in a plastic packaging bag are cooked in a microwave when eating. When heated in a microwave oven, the internal pressure of the packaging bag rises due to the thermal expansion of the steam and internal air generated from the contents, and the packaging bag expands. However, if it expands too much, the packaging bag may break and the contents stored in the packaging bag may scatter.

  For this reason, conventional microwave heating packaging bags have been provided with a steam venting means that vents steam during range heating so that when the internal pressure of the packaging bag increases due to heating of the microwave oven, the internal pressure is automatically released to prevent bursting. ing.

  FIG. 8 is a perspective view showing a conventional packaging bag 100 for heating a microwave oven. In this microwave heating packaging bag 100, the left and right ends of a single synthetic resin film are joined together to form a joined part 101, the film is formed into a cylindrical shape, and the joined part 101 is in the center. The opening at the upper end and the opening at the lower end of the cylinder are heat sealed so as to be arranged. Here, the steam venting means is formed by weakening a part or all of the joints.

  When the microwave heating packaging bag 100 containing the contents such as food is heated in the microwave oven, the microwave heating packaging bag 100 expands as shown in FIG. As a result, peeling occurs in the palm portion 101, and gas such as water vapor and expanded air inside escapes out of the bag through the resulting hole.

As described above, Patent Literatures 1 to 3 disclose microwave oven heating packaging bags provided with vapor venting means for preventing the bag from overexpanding and bursting due to heating of the microwave oven.
Also, Patent Documents 4 and 5 disclose packaging bags for heating a microwave oven in which when the internal pressure at the time of expansion is released to the outside of the bag, the vapor venting means is moved upward to prevent leakage of contents from the vent hole of the vapor venting means. Is disclosed.
Japanese Patent No. 3035484 JP 2000-159276 A Japanese Unexamined Patent Publication No. 2000-168851 Japanese Patent No. 3597656 JP 2005-59870 A

  However, in the microwave oven heating packaging bags shown in Patent Documents 4 and 5, the position of the vapor removal means moves upward during heating expansion, but the packaging bag rolls over because the packaging bag approaches a spherical shape as it expands. There is a possibility that the steam venting means moves to the side or downward and the contents leak from the steam venting means.

  The present invention has been created in view of the above points, and has an object to provide a microwave heating packaging bag and a method for manufacturing the same, which can prevent the packaging bag from overturning when heated and inflated. .

  In order to achieve the above object, the microwave oven heating packaging bag of the present invention is made of a rectangular resin film and is formed by sealing two opposite sides of the resin film, and this seal is peeled off by internal pressure during microwave heating. A steam vent part through which steam escapes, a bottom surface facing the steam vent part, a pair of side seal parts provided along the longitudinal direction at both ends in the width direction of the bottom face, the steam vent part and the pair of side parts And a pair of pleat portions provided between the seal portion.

  The pleat part is configured, for example, by bending a resin film positioned between the vapor vent part and the pair of side seal parts so as to protrude outward by a fold line along the longitudinal direction.

  In addition, it is desirable that the microwave heating packaging bag is folded flat and the pleat portion is positioned on the inner side in the width direction than the side seal portion.

  It is desirable that the seal strength of the steam vent is weaker than the seal strength of the side seal.

  In the unfolded state, the distance between the side seal part and the steam vent part is preferably longer than the distance between the side seal parts.

  The microwave oven heating packaging bag is desirably folded in a flat state, and the number of overlapping resin films is preferably 4 or less at any position.

  The end side of the pleat part may be sealed.

  It is desirable that the pleat part and the side seal part do not overlap in a state where the pleat part is folded flat.

  The first method for manufacturing a microwave heating packaging bag according to the present invention includes a step of heat-sealing two opposing sides of a single rectangular synthetic resin film to form a vapor vent, and a vertical center of a side surface. The steps of forming the pleat by folding the upper part inward and the step of heat-sealing the left and right end points of the bottom surface to form the side seal portion are included in the above order.

  The second method for manufacturing a microwave heating packaging bag according to the present invention includes a step of bending a side of a rectangular synthetic resin film into a U-shaped cross section and then folding the side surface inward to form pleats; The steps of forming the steam vent by heat-sealing the left and right edges and the step of heat-sealing the left and right end points of the bottom surface to form the side seal portion are included in the above order.

  According to the microwave oven heating packaging bag of the present invention, when the microwave oven is heated, the vapor escapes from the vapor vent and the bottom surface expands, while the entire microwave heating packaging bag expands, so that the pair of side seal portions are left and right. Projects downward and prevents rollover of the microwave heating packaging bag.

  When it has a pleat part, while being able to keep the height of a steam vent part enough, a side seal part protrudes further and the rollover of the microwave oven heating packaging bag is stopped.

  When the pleat part is formed by bending a resin film located between the vapor vent part and the pair of side seal parts so as to protrude outward by a fold line along the longitudinal direction, microwave heating Sometimes, the folded surface is expanded by the internal pressure, and the side seal portion further protrudes to prevent the microwave heating packaging bag from overturning.

  When the microwave oven packaging bag is folded flat and the number of overlapping resin films is 4 or less at any position, the sealing strength is increased.

  When the seal strength of the steam vent is weaker than the seal strength of the side seal, only the seal of the steam vent is peeled without peeling the seal of the side seal.

  When the distance between the side seal part and the steam vent part is longer than the distance between the side seal parts in the unfolded state, the height of the steam vent part can be kept sufficiently and the side seal part protrudes further. Prevents rollover of packaging bags for microwave oven heating.

  According to the method for manufacturing a packaging bag for heating a microwave oven of the present invention, a packaging bag for heating a microwave oven that prevents rollover can be manufactured.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a packaging bag for heating a microwave oven according to the present invention, in which (A) shows a state before storing contents, and (B) shows after storing contents and heating them in a microwave oven. Each state is shown. FIG. 2 is a cross-sectional view schematically showing an AA portion in FIG. FIG. 3 is an enlarged view of a portion C in FIG. FIG. 4 is a development view of the microwave oven heating packaging bag of FIG. 1. FIG. 5 is an arrow view showing a state viewed in the direction of arrow B in FIG. In the figure, arrow W indicates the width direction, arrow L indicates the longitudinal direction, and arrow H indicates the height direction.

  The microwave heating packaging bag 1 is configured by folding one rectangular synthetic resin film 1A shown in FIG. 4 and joining the portions shown shaded in FIG. 4 by heat sealing. As shown in FIG. 3, each synthetic resin film 1 </ b> A is configured as a laminate of a base material layer 11 </ b> A and a sealant layer 11 </ b> B provided on the entire surface of one surface, that is, a heat-sealing layer. It is configured with the surface facing the inside of the bag. In FIG. 3, the thickness of the synthetic resin film 1A is shown to be thicker than the actual thickness.

  The material of the synthetic resin film 1A is not particularly limited as long as it has the sealant layer 11B on one side of the base material layer 11A, but for the base material layer 11A, for example, polyester, polypropylene, polyamide, or the like can be used. Further, as a multilayer film or sheet, in addition to a laminate of a plurality of different resins, a film or sheet with a metal or a vapor deposition layer such as a metal oxide such as alumina or silica is used as the base layer 11A. Can do. For example, an intermediate layer may be provided between the base material layer 11A and the sealant layer 11B. As the intermediate layer, a film of polyethylene terephthalate, polyamide, polyethylene, polypropylene, polyolefin or the like can be used.

  The resin constituting the sealant layer 11B can be selected from general heat-sealable resins in consideration of the melting point and the seal strength. Specifically, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, An ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, an ionomer resin, or the like can be used.

  As shown in FIGS. 1 and 2, the microwave heating packaging bag 1 has a steam vent 13 at the upper center in the width direction and side seals 12 at the left and right ends. The steam vent 13 is formed by stacking and heat-sealing the left and right edges 3 of one rectangular synthetic resin film 1A. The heat seal of this part is joined by a method different from other heat seal parts so that a part or all of the joints become brittle. Therefore, when the microwave oven heating packaging bag 1 containing the contents such as food is heated in the microwave oven, the microwave oven heating packaging bag 1 expands as shown in FIG. Then, the synthetic resin films 1A forming the vapor vents 13 are separated from each other by the internal pressure, and gas such as internal water vapor and inflated air escapes out of the bag through the resulting holes. In FIG. 1, the heat seal portion is represented by a cross hatch.

  As shown in FIG. 2, the side seal portion 12 is formed by folding the synthetic resin film 1 </ b> A at the left and right positions. More specifically, the side seal portion 12 is formed by mountain-folding the side seal end side 2 as a turning point and heat-sealing the overlapped side portions. Unlike the steam release part 13, the side seal part 12 is firmly joined so that peeling does not easily occur even when the microwave heating packaging bag 1 is heated in a microwave oven. As shown in FIG. 4, in the unfolded state, the distance from the left and right side seal edges 2 to the left and right edges 3 constituting the steam vent is slightly longer than the distance between the left and right side seal edges 2. For this reason, in the expansion | swelling state of the packaging bag 1 for microwave oven heating, the height of the steam extraction part 13 can fully be maintained. 2 shows a state in which the microwave heating packaging bag 1 is slightly expanded in the height direction for the sake of clarity, but in actuality, when the contents are not accommodated, FIG. ) Becomes flat.

  As shown in FIG. 2, the microwave heating packaging bag 1 has a pleat portion 7 between the left and right side seal portions 12 and the steam vent portion 13. The pleat part 7 is a part generally called a gusset or a gusset part, and the pleat edge 5 formed by folding the film in a mountain and the film is valley-folded closer to the center in the width direction than the pleat edge 5. The pleat folding side 6 formed in this way, the pleat lower surface 15 located between these, and the part which faces the pleat lower surface 15 among the 1st upper surfaces 14 mentioned later are included. A first upper surface 14, a pleat lower surface 15, and a second upper surface 16 are formed between the steam vent 13, the pleat end side 5, the pleat folding side 6, and the side seal portion 12, respectively. A bottom surface 11 is formed between the side seal portions 12.

  As shown in FIG. 2, the microwave heating packaging bag 1 has a middle side 4 generated by folding back the steam vent 13 on either the left or right side at a substantially central portion in the width direction in the vicinity of the steam vent 13. The microwave heating packaging bag 1 is folded flat, and the pleat folding side 6, the pleat end side 5, and the side seal end side 2 are located in order from the middle side 4 to the outside, and either the left or right side In the right side in the figure, the end side 3 is located between the middle side 4 and the pleated folded side 6. Further, the side seal part 12 and the steam vent part 13 do not overlap any of the middle side 4, the pleat end side 5, and the pleat folding side 6. However, since the pleat folding side 6 and the end side 3 are located as close as possible so as not to contact each other, and the pleat end side 5 is located as close as possible so as not to contact the side seal portion 12, the content is particularly solid. In some cases, the filling operation becomes easy. Here, a portion including the portion between the end side 3 and the middle side 4 on the first upper surface 14 and the vapor venting portion 13 is referred to as a palm portion 8. A portion including the second upper surface 16, the side seal portion 12, and a portion of the bottom surface 11 facing the second upper surface 16 is referred to as a leg portion 9.

  Moreover, it is good also as the pleat end side 25 which sealed the pleat end side like the packaging bag 21 for microwave oven heating of the modification shown in FIG.2 (B). In this case, the seal width of the pleat end side 25 is desirably narrower than the seal width of the side seal portion 12. This is because, when the microwave oven heating packaging bag 21 is inflated, its shape is easily maintained. Since the microwave heating packaging bag 21 is the same as the microwave heating packaging bag 1 except that the pleat edge 25 is sealed, the same reference numerals as those of the microwave heating packaging bag 1 are attached. The description is omitted.

  As shown in FIG. 1 (A), one end in the longitudinal direction of the microwave heating packaging bag 1 is joined by heat sealing to form an end seal portion 20. As with the side seal portion 12, the end seal portion 20 is firmly bonded so that no peeling occurs even when heated in a microwave oven. The microwave heating packaging bag 1 is sold to a food manufacturer or the like with an end seal portion 20 formed at one end in the longitudinal direction and the other end opened. The contents are stored, and then the other end is joined by heat sealing. In this way, the end seal portion at the other end (not shown) provided at the other end is firmly joined so that peeling does not occur even when heated in a microwave oven, like the end seal portion 20.

  In addition, although illustration is abbreviate | omitted, as a modification of the packaging bag 1 for microwave oven heating, you may heat-seal for chamfering in the four corners produced by an end seal part and a side seal part. The heat seal for chamfering may be a straight line that skews with respect to the end seal part and the side seal part, or may be a round shape with an inner edge bulging outward. By applying such heat sealing for chamfering, the internal angle of the figure formed by each seal part in a plan view is not a right angle but an obtuse or rounded shape, so the contents are in the internal corner part when opening. It can be prevented from remaining. Moreover, since the heat seal width at the four corners is wider than the other parts, this part can also be used as a handle. Such a heat seal part for chamfering can be provided when the end seal part is sealed or when the side seal part is sealed.

  The microwave heating packaging bag 1 configured as described above has an end seal portion 20 in a state of being folded flat as shown in FIGS. 1 (A) and 2. In the end seal portion 20, two or four synthetic resin films 1A overlap each other. However, since the inner surface of the synthetic resin film 1A is the sealant layer 11B, the portion where the sealant layers 11B face each other. All can be joined simultaneously by a single heat sealing process. Here, heat sealing melts the sealant layer 11B with heat and applies pressure to bond them, so that the synthetic resin film 1A has higher sealing strength as the number of overlapping sheets decreases.

  In the microwave oven packaging bag 1, the maximum number of overlapping films is four. Therefore, when heating is performed from above and below the microwave heating packaging bag 1 to form the above-described end seal portion 20, heat and pressure are efficiently transmitted to the sealant layer 11B. Accordingly, the occurrence of pinholes or the like in the end seal portion 20 at one end and the end seal portion at the other end can be suppressed, and bonding can be performed reliably.

  The microwave heating packaging bag 1 is configured such that the side seal portion 12 does not overlap any of the middle side 4, the pleat end side 5, and the pleat folded side 6. As shown in FIGS. 6 (E) and 7 (F), when the side seal portion 12 is formed, the pleat edge 5 is not sealed, and any of the films is used to prevent the pleat edge 5 from being sealed. There is no need to wrap the face. Therefore, the microwave heating packaging bag 1 can be easily formed. By not sealing the pleat edge 5, the amount of the synthetic resin film 1 </ b> A used can be reduced, and the microwave heating packaging bag 1 can be sufficiently expanded during heating.

[Behavior during heating]
Next, the behavior when the contents are stored in the microwave heating packaging bag 1 and heated in the microwave will be described. As shown in FIG. 1 (B) and FIG. 5 (A), when the microwave heating packaging bag 1 containing contents such as food is heated in a microwave oven, the internal water vapor or expanded air causes the internal The volume of the gas increases, and the microwave heating packaging bag 1 expands to have a rounded shape. Moreover, a side seal part and a steam vent part protrude in the outer side direction of the packaging bag 1 for microwave oven heating, and stand up gradually. By further heating, the microwave heating packaging bag 1 is further expanded, and the volume of the gas in the microwave heating packaging bag 1 becomes equal to the volume of the microwave heating packaging bag 1. Then, as shown in FIG. 5 (B), the longitudinal direction or the cross-sectional shape approaches a so-called rouleau triangular shape. Further, in the end seal portion 20, an angle θ formed between the pleat end side 5 and the side seal end side 2 with respect to the pleat folding side 6 is increased, and an angle θ2 with respect to the horizontal of the left and right side seal portions 12 is also increased. When further heated, the volume of the gas in the microwave heating packaging bag 1 exceeds the volume of the microwave heating packaging bag 1, and tension is applied to the synthetic resin film 1 </ b> A to form the vapor vent 13. The side 3 is pulled in the left-right direction, and coupled with the weakening of the seal strength of the steam vent 13 due to heat, peeling of the heat seal occurs in the steam vent 13 and a hole is formed. On the other hand, since the side seal part 12 is firmly welded, the shape before heating is maintained.

  As shown in FIGS. 1B and 5, even when the microwave heating packaging bag 1 approaches a circular cross section and the bottom surface 11 bulges and easily rolls over, the side seal portion 12 is left and right downward. The side seal portion 12 acts like a foot by protruding and pleating the lower surface 15 of the pleat 15 and the second upper surface 16 and stretching in the vertical direction, so that the rollover of the packaging bag 1 for heating a microwave oven is prevented. Therefore, the steam vent 13 is always located at the upper part, and is not located on the side or below, so that the contents can be prevented from overflowing from the steam vent 13. Here, even if the pleat portion 7 is not provided, the side seal portion 12 protrudes in the left-right downward direction. However, when the pleat portion 7 is provided, the pleat folding side 6 is particularly connected to the pleat portion 7 and the end seal portion 20. Since the leg portion 9 moves upward as the leg portion 9 bulges, the angle of the side seal portion 12 approaches vertically. This is because the base portion between the leg portion 9 and the pleat portion 7 is joined at the pleat folding side 6 in the end seal portion 20, and the pleat portion 7 and the leg portion 9 are expanded as the pleat portion 7 and the leg portion 9 swell. This is because the pleat edge 5 and the side seal edge 2 positioned at the tip act in a direction away from each other, and the angle θ1 gradually opens as shown in FIG.

  Further, as shown in FIG. 5, the pleat portion 7 is unfolded by the expansion of the microwave heating packaging bag 1, and the distance between the left and right side seal edges 2 and the left and right side seal edges 2 are The distance to the edge 3 is substantially the same. Then, as shown in FIG. 5, the angle θ2 gradually opens, and the side seal portion 12 rises in a leg shape with respect to the floor surface. Therefore, the side seal portion 12 protrudes from the microwave heating packaging bag 1 in the lower left and lower right directions, and can further prevent the microwave heating packaging bag 1 from overturning than when the pleat portion 7 is not provided.

  Further, as shown in FIGS. 1B and 5, when the microwave heating packaging bag 1 is heated and expanded, the palm portion 8 and the steam vent portion 13 are pushed upward and perpendicular to the bottom surface 11. Stand up. Therefore, the steam vent 13 is positioned above the contents, and the steam vent 13 can be broken and opened. The microwave heating packaging bag 1 has a pleat portion 7, and the total length of the left and right first upper surfaces 14, the pleated lower surface 15, and the second upper surface 16 is longer than the bottom surface 11. Thus, by having the pleat part 7, the steam venting part 13 becomes a position higher than the case where the pleat part 7 is not provided.

  When opening the packaging bag 1 for heating a microwave oven by breaking the steam vent 13 and the contents and the steam vent 13 are close to each other, the heat of the contents is transmitted and is difficult to open. However, when the microwave heating packaging bag 1 is heated, the steam vent 13 rises to a high position away from the contents, and the steam vent 13 is separated from the contents. Moreover, the packaging bag 1 for microwave heating once expanded substantially maintains its shape until the steam vent 13 is broken and opened even after the heating is finished. Therefore, it is easy to break the steam vent 13, and when taking out the heated contents, it is possible to prevent the contents from being touched by mistake.

[Method of manufacturing packaging bag for heating]
Next, the manufacturing method of the packaging bag 1 for microwave oven heating is demonstrated. The packaging bag 1 for heating a microwave oven flows into the line process from the end without cutting a long synthetic resin film wound in a roll shape, and is cross-sectioned by gradually adding a folding process and a heat seal process in the line process. The shape is changed, and finally, it is cut into an appropriate length, and the end seal part 20 at one end in the length direction is joined by heat sealing, and the other end is opened in a shipped state. Hereinafter, the change of the cross-sectional shape in the manufacturing method of this packaging bag 1 for microwave oven heating is demonstrated in order.

[First production method]
FIG. 6 is a diagram schematically showing a first manufacturing method of the microwave heating packaging bag 1.
First, the left and right edges 3 of one rectangular synthetic resin film 1A shown in FIG. 6A are overlapped with each other as shown in FIG. 6B, and an appropriate width is indicated by an arrow. The steam vent 13 is formed by heat sealing. Here, as described above, part or all of the steam vent 13 is weakly sealed. Specifically, such a heat seal can be obtained by lowering the temperature at the time of heat sealing of this part or by sandwiching another sealant agent in this part. Next, as shown in FIG. 6 (C), after forming the side surface 7a as a pretreatment for forming the pleats 7 on the left and right sides of the film, as shown in FIG. 6 (D), from the center in the vertical direction of the side surface 7a. The upper part is folded inward by the top K to form the pleats 7. And as shown to FIG.6 (E), it heat-seals as shown by the arrow by appropriate width | variety at the left and right end points outside a pleat, and forms a side seal part.

[Second production method]
FIG. 7 is a view schematically showing a second manufacturing method of the microwave heating packaging bag 1. The second manufacturing method of the microwave heating packaging bag 1 is different from the first manufacturing method shown in FIG. 6 in that the steam vent 13 is formed after the pleat portion 7 is formed.

  First, a rectangular synthetic resin film 1A as shown in FIG. 7A is valley-folded from the right and left so as to form a bottom surface 11 at the center as shown in FIG. After forming the pleat 7, a part of the side surface 7 a is folded inward by the top K as shown in FIG. Next, as shown in FIG. 7 (D), the left and right sides of the film are overlapped and overlapped, and the steam vent 13 is formed by heat-sealing by an appropriate width. Subsequently, as shown in FIG. 7E, a mountain fold is formed between the pleat 7 and the steam vent 13 to form a first upper surface 14 and a pleat folding surface 15. Then, as shown in FIG. 7 (F), heat sealing is performed to form side seal portions as indicated by arrows with appropriate widths at the left and right end points outside the pleats.

  After the cross-sectional shape is formed by the first or second manufacturing method described above, the end synthetic resin film 1A is formed in the end seal portion 20 by performing heat sealing perpendicularly to the length direction at appropriate intervals. Is done. Subsequently, the synthetic resin film 1 </ b> A is cut along the end seal portion 20 so as not to overlap the end seal portion 20. At this time, the cutting line may be a straight line, but notches are formed at both ends in the length direction by cutting with a zigzag line. The microwave heating packaging bag 1 is sold to a food manufacturer or the like with the end seal portion 20 formed at one end in the longitudinal direction and the other end opened through the above process. The contents are stored through the opening, and then the other end is joined by heat sealing and sold.

  As mentioned above, although the microwave oven packaging bag of this invention and its manufacturing method were demonstrated, this invention is not limited to the dimension and shape of said structure, A suitable change can be made. For example, even if the pleat portion is not provided, rollover can be prevented, and a plurality of pleat portions may be provided in order to increase the height during expansion. Although the middle side 4 is shown in FIG. 2, the middle side may be biased to either the left or right side. Moreover, you may comprise the pleat part 7 so that it may become asymmetrical.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows typically embodiment of the packaging bag for microwave oven heating of this invention, (A) shows the state before content storage, (B) shows the state after heating with a microwave oven, respectively. . 2A is a cross-sectional view taken along line AA in FIG. 1A, and FIG. 2B is a diagram showing a microwave heating packaging bag according to a modified example from the same viewpoint as FIG. It is an enlarged view of the C section of FIG. It is an expanded view of the packaging bag for microwave oven heating of this invention. (A) is a B direction arrow line view in FIG. 1 (B), (B) is a figure which shows the subsequent state in the same viewpoint as (A). It is a figure which shows typically the 1st manufacturing method of the packaging bag 1 for microwave oven heating. It is a figure which shows typically the 2nd manufacturing method of the packaging bag 1 for microwave oven heating. It is a perspective view which shows the conventional packaging bag for microwave oven heating. It is a figure which shows the use condition of the packaging bag for microwave ovens of FIG.

Explanation of symbols

1,21 Microwave oven packaging bag 1A Synthetic resin film 2 Side seal edge 3 Edge 4 Middle 5,25 Pleated edge 6 Pleated folding edge 7 Pleated part 7a Side surface 11 Bottom surface 11A Base material layer 11B Sealant layer 12 Side Seal portion 13 Vapor vent portion 14 First upper surface 15 Pleated lower surface 16 Second upper surface 20 End seal portion

Claims (10)

A microwave oven packaging bag made of a rectangular resin film,
Formed by sealing two opposite sides of the resin film, and a steam vent from which the steam escapes when the seal peels off during microwave heating,
A bottom surface facing the steam vent, and
A pair of side seal portions provided along the longitudinal direction at both ends in the width direction of the bottom surface;
A pair of pleats provided between the steam vent and the pair of side seals;
A packaging bag for heating a microwave oven.   The pleat portion is configured by bending a resin film positioned between the vapor vent portion and the pair of side seal portions so as to protrude outward by a fold line along a longitudinal direction. A packaging bag for heating a microwave oven as described in 1.   The packaging bag for heating a microwave oven according to claim 1 or 2, wherein the pleat portion is positioned inward in the width direction from the side seal portion in a state of being folded flat.   The packaging bag for heating a microwave oven according to any one of claims 1 to 3, wherein a seal strength of the steam vent is weaker than a seal strength of the side seal.   The packaging bag for heating a microwave oven according to any one of claims 1 to 4, wherein a distance between the side seal part and the vapor vent part is longer than a distance between the side seal parts in the unfolded state.   The packaging bag for heating a microwave oven according to any one of claims 1 to 5, wherein the number of overlapping resin films is 4 or less at any position in a state of being folded flat.   The packaging bag for heating a microwave oven according to any one of claims 1 to 6, wherein an end side of the pleat portion is sealed.   The packaging bag for heating a microwave oven according to any one of claims 1 to 7, wherein the pleat part and the side seal part do not overlap in a state of being folded flat. Heat-sealing two opposite sides of one rectangular synthetic resin film to form a vapor vent;
Folding the part above the vertical center of the side surface inward to form pleats;
Heat sealing the left and right edges of the bottom to form a side seal part;
The manufacturing method of the packaging bag for microwave oven heating containing these in the above order. After bending one rectangular synthetic resin film into a U-shaped cross-sectional shape, folding the side face inward to form pleats;
Heat sealing the left and right edges to form a vapor vent; and
Heat sealing the left and right edges of the bottom to form a side seal part;
The manufacturing method of the packaging bag for microwave oven heating containing these in the above order.