Automatic Ventilated Packaging Bag

Abstract

To provide a vertical stand-up, automatically gas-releasable packaging bag allowed to favorably discharge gas with a simpler structure as compared with the conventional one and easy and clear to grasp an opening position for opening with safety.SOLUTION: An automatically gas-releasable packaging bag comprises a side edge-gradually reducing sealed portion 20, in a release-sided side edge 12, that has a heat-seal width W1 decreasing in a direction toward a top opening 15 from a bottom edge 14 side, a to-be-released portion 30 that has a heat seal width W5 narrower than the heat-seal width of the side edge-gradually reducing sealed portion and is heat-sealed with an arcuate protrusion directed toward a central portion of a packaging bag 10, a discharge gas-passing portion 40 that is provided not heat-sealed between film bodies on the back side of the to-be-released portion, and a protruding portion 50, in a release-sided side edge 13, that is provided heat-sealed with a protrusion directed toward a central portion in the vicinity of an opposed position to the to-be-released portion. In the protruding portion, an open-instruction point 51 is formed specifying an open-start point for tearing an upper side of the packaging bag in removing the content.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vertically-positioned automatic ventilation packaging bag that prevents the packaging bag from bursting by automatically venting water vapor generated from the contents when the contents are heated together with the packaging bag. [Background technology]

[0002] In recent years, pre-cooked or partially pre-cooked processed foods have become widely used and distributed to simplify meal preparation and serving. Demand for these foods has increased, particularly due to a decline in the number of people per household and the need to reduce cooking costs at restaurants. For convenience, these pre-cooked foods are packaged in various plastic film containers and packaging bags. Pre-cooked foods are often heated in two ways: in a hot water bath or in a microwave oven (high-frequency range). Microwave heating is particularly popular due to its reduced cooking time and simplified operation. Therefore, plastic film food packaging has been designed with improved heat and pressure resistance to accommodate microwave heating. When heated in a microwave oven, the container expands due to the vapor generated by evaporation of the food contents. However, there is a limit to the container's expansion. When a certain internal pressure is reached, the container (packaging bag) can burst, posing a serious risk. This also contaminates the microwave oven.

[0003] Previously, to prevent the container (packaging bag) from bursting due to water vapor, users had to puncture the container (packaging bag) before heating, which was time-consuming. While some containers (packaging bags) exist with pre-made holes, the airtightness of the container itself is not very good, and they are primarily limited to packaging frozen foods and the like. Therefore, to improve the airtightness of the container itself and ensure an escape route for water vapor, packaging bags equipped with an automatic vent in part of the container or packaging bag have been proposed. Although the automatic vent is always closed, it is the first to open when heated due to the expansion pressure of water vapor generated by the contents. The filled water vapor is released to the outside of the packaging bag, acting as a safety valve to reduce the pressure inside the container.

[0004] The present inventors have developed an automatic venting packaging bag that has a simpler structure than conventional bags and is capable of venting water vapor appropriately and safely (see, for example, Patent Document 1). This automatic venting packaging bag has side constant-width sealed portions at its side edges where the heat-seal width is constant from the open-mouth side to the bottom edge, and side gradually tapering sealed portions where the heat-seal width decreases from the side constant-width sealed portions to the bottom edge, and the bottom edge has bottom gradually tapering sealed portions where the heat-seal width decreases from both ends of the bottom edge to the center, and the center of the bottom edge has a ventilation portion that has a heat-seal width narrower than the heat-seal width of the bottom gradually tapering sealed portion and is heat-sealed to protrude in an arc toward the center of the packaging bag, and an exhaust passage portion that is not heat-sealed between the film bodies is provided behind the ventilation portion in the bottom edge.

[0005] In the above-mentioned automatic venting packaging bag, the entire bag expands due to the steam generated from the contents when heated in a microwave oven, and the expansion force of this steam is used to collect the steam in the ventilation section, causing it to break and vent the steam. At this time, when the ventilation section is broken, the exhaust passage allows the steam inside the bag to pass through and be vented to the outside of the bag.

[0006] In recent years, there has been an increasing demand for vertically-positioned, so-called self-standing packaging bags to reduce the effort required for product display and improve visibility in convenience stores and other locations. These vertically-positioned packaging bags are placed in a microwave oven in an upright position for heating. After cooking, the top of the packaging bag is cut open and the contents are transferred to a dish, or the bag is cut open and eaten directly from the bag. In particular, vertically-positioned packaging bags for microwave heating require a steam vent position at the top, which poses a risk of bringing fingers close to the vent position when opening the bag. For this reason, although the opening position is clearly indicated, problems such as limitations on package design have arisen. Therefore, there is a need for an automatically vented vertically-positioned packaging bag that is simple in structure and does not require a complex structure, yet is capable of good ventilation and allows the opening position to be easily identified. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6561035 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above points, and provides an automatic ventilation packaging bag of a vertical type that is capable of performing good ventilation with a simpler structure than conventional bags, and that can be opened safely because the opening position can be easily and clearly identified. [Means for solving the problem]

[0009] That is, the first invention is a vertically placed packaging bag formed by heat-sealing both side edges and the bottom edge of a laminated film body, and having an upper opening that is heat-sealed to become the upper edge after the contents are placed inside, and on one of the both side edges, the exhaust side edge, 、 The heat seal width from the bottom side to the top opening side (W1) is reduced and The tilt angle 3 to 11 degrees The tapered seal portion has a minimum heat seal width of the side edge. (W3) Narrower heat seal width (W5) The packaging bag has a heat-sealed ventilation section that protrudes in an arc shape toward the center of the packaging bag, and an exhaust passage section that is not heat-sealed between the film bodies is provided behind the ventilation section in the exhaust side edge section, and the other of the both side sections, the open side edge section, has a protrusion that protrudes toward the center near a position facing the ventilation section and is heat-sealed, and the open side edge section is connected to the protrusion from the bottom side. hand Heat Seal Width (W6) increases and Inclination angle: 15 to 21 degrees isThe present invention relates to an automatically ventilated packaging bag characterized by having a gradually increasing seal portion on the side edge, and an opening instruction portion formed on the protruding portion that specifies the starting position for opening the upper side of the packaging bag when removing the contents.

[0010] (delete)

[0011] The second invention relates to an automatically ventilated packaging bag in accordance with the first invention, which is provided with upper side gradually increasing seal portions on both side edges that are connected from the upper opening side to the ventilation portion and the protruding portion, respectively, and which increase the heat seal width.

[0012] A third invention relates to the automatic ventilation packaging pouch of the first invention, wherein the protruding portion has an uneven portion formed thereon to indicate the opening indication portion.

[0013] A fourth aspect of the present invention relates to the automatic ventilation packaging pouch of the third aspect, in which a Braille display portion is formed by the concave-convex portion. [Effects of the Invention]

[0014] The automatic ventilation packaging bag according to the first aspect of the present invention is a vertically placed packaging bag having an upper opening formed by heat-sealing both side edges and a bottom edge of a stacked film body, and heat-sealing the upper edge after the contents are placed inside the bag, and the exhaust side edge, which is one of the both side edges, has a 、 The heat seal width from the bottom side to the top opening side (W1) is reduced and The tilt angle 3 to 11 degrees The tapered seal portion has a heat seal width of 20 mm. Minimum side heat seal width The packaging bag has a ventilation section that has a narrower heat seal width and is heat-sealed so as to protrude in an arc shape toward the center of the packaging bag, and an exhaust passage section that is not heat-sealed between the film bodies is provided behind the ventilation section in the exhaust side edge section, and a protrusion that protrudes toward the center and is heat-sealed in the vicinity of the opposing position of the ventilation section is provided on the open side edge section, which is the other of the both side edges, and is connected to the protrusion from the bottom edge side to the open side edge section. handHeat seal width inclination angle 15 to 21 degrees is It is equipped with a gradually increasing seal portion on the side edge, and the protruding portion is formed with an opening indicator portion that specifies the starting position for opening the upper side of the packaging bag when removing the contents.As a result, it is possible to achieve good ventilation with a simpler structure than conventional ones, and the opening position can be easily and clearly grasped, allowing for safe opening.

[0015] (delete)

[0016] According to the second invention, the automatic ventilation packaging bag of the first invention is provided with an upper side gradually increasing seal portion on both side edges that is connected from the upper opening side to the ventilation portion and the protrusion portion, respectively, and increases the heat seal width, so that the contents do not accumulate above the ventilation portion or the protrusion portion, making it less likely to spill when opened.

[0017] According to the third invention, the automatic ventilation packaging bag of the first invention has an uneven portion formed on the protruding portion to indicate the opening instruction portion, making it easier and clearer to grasp the opening start position.

[0018] According to the automatic ventilation packaging bag of the fourth invention, in the third invention, the Braille display portion is formed by the uneven portion, making it easier and clearer for visually impaired people in particular to understand the starting position for opening. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a front view of an automatic ventilation packaging bag according to an embodiment of the present invention; [Figure 2] 1 is an overall perspective view of an automatic ventilation packaging bag according to an embodiment of the present invention in which an upper side portion is formed. FIG. [Figure 3] 1 is a schematic diagram of the area around the exhaust side edge of the automatic ventilation packaging bag. FIG. [Figure 4] 1 is a schematic diagram of the opening side edge portion of an automatic ventilation packaging bag. [Figure 5] 1 is a schematic diagram of an automatic ventilation packaging bag having an upper gradually increasing seal portion formed therein. [Figure 6] FIG. 1 is a conceptual diagram of the expansion of an automatic ventilated packaging bag. DETAILED DESCRIPTION OF THE INVENTION

[0020] 1 and 2, an automatic ventilation packaging bag 10 according to one embodiment of the present invention is a vertically-positioned packaging bag produced by heat-sealing a film body. This automatic ventilation packaging bag 10 is suitable for use as a packaging bag for foods such as retort foods and frozen foods, and can be heated and cooked together with the packaging bag 10 in a microwave oven (high-frequency range, microwave oven). After the contents are filled into this packaging bag 10, it is retort sterilized. Because the automatic ventilation packaging bag 10 of the present invention is a self-standing, so-called vertically-positioned packaging bag, the contents to be filled are not particularly limited, and it can also be used for foods with a lot of liquid.

[0021] The film body is a known film material for retort packaging. Examples of the film body include biaxially oriented films made of polypropylene film, polyamide film, polyester film, ethylene-vinyl alcohol copolymer, etc., biaxially oriented polyester film vapor-deposited with aluminum oxide, biaxially oriented polyester film vapor-deposited with silica, oriented polymetaxylylene adipamide-based polyamide film, and heat-resistant films compatible with microwave ovens (high-frequency ranges), such as co-extruded laminate films of these with nylon 6 or the like. Typically, the films listed above are two-layer or three-layer or more laminate films formed by laminating a sealant film that contacts the contents and is the surface that is fused together by heat sealing, and a polyamide resin or polyester resin film that protects the sealant film. The film body is selected taking into consideration a comprehensive range of factors, such as the thickness of each film layer, the number of layers, the resin composition, the properties of the contents, the heat resistance temperature, the heat sealing temperature, the strength as a packaging bag, the distribution route, the distribution form, etc. For example, a polypropylene film such as ZK93KM manufactured by Toray Advanced Film Co., Ltd. is used, and a polymetaxylylene adipamide-based stretched polyamide film such as SP-R manufactured by Mitsubishi Plastics, Inc. is used.

[0022] As shown in Fig. 1, the automatic ventilation packaging bag 10 has both side edges 11, 11 and a bottom edge 14 of overlapping film bodies heat-sealed, and has an upper opening 15 on the other side (top edge) that is not heat-sealed. Then, as shown in Fig. 2, after the contents are placed (filled), the upper opening 15 is heat-sealed to form an upper edge 16, resulting in a vertically placed packaging bag. In this automatic ventilation packaging bag 10, one of the heat-sealed both side edges 11, 11 is configured as an exhaust side edge 12, and the other as an open side edge 13.

[0023] As shown in Figure 3, the exhaust side edge portion 12 comprises a side edge tapering seal portion 20, a ventilation portion 30, and an exhaust passage portion 40. The side edge tapering seal portion 20 is a portion that is heat-sealed so that the heat seal width W1 decreases from the bottom edge portion 14 toward the top opening 15. The shape of the side edge tapering seal portion 20, in which the heat seal width W1 decreases toward the top opening 15, acts to concentrate the internal pressure during thermal expansion upward (particularly toward the ventilation portion 30, which will be described later). The inclination angle of the side edge tapering seal portion 20 is desirably approximately 3 to 11 degrees, and preferably approximately 8 degrees.

[0024] Furthermore, a fixed-width side seal portion 21 is formed on the bottom 14 side of the tapered side seal portion 20 in accordance with the vertical scale of the packaging bag 10. The fixed-width side seal portion 21 is a portion that is heat-sealed so that the heat seal width W2 between the tapered side seal portion 20 and the bottom 14 is constant. The heat seal width W2 of the fixed-width side seal portion 21 is determined appropriately depending on the contents, but is preferably approximately 8 to 10 mm. If the heat seal width W1 is too narrow, it may be difficult to form the tapered side seal portion 20. Conversely, if the heat seal width is too wide, the fusion margin will be large, which will impair the appearance and increase the amount of film used.

[0025] As shown in FIGS. 1 to 3, the ventilation section 30 extends upward from the center of the exhaust side edge 12 to the width of the heat seal of the gradually tapering seal section 20. W1This heat-sealed section has a heat-seal width W5 narrower than the minimum heat-seal width W3 of the side edge and protrudes in an arc shape toward the center of the packaging bag 10. This ventilation section 30 allows water vapor inside the bag to be released when the automatic venting packaging bag 10 expands due to water vapor generated from the contents during cooking.

[0026] As shown in Figure 3, the ventilation section 30 has a flat trapezoidal shape. When the ventilation section 30 is heated and expanded, the adhesion between the heat-sealed films is first broken (ruptured), and the water vapor inside the bag is released. The ventilation section 30 is an intentionally formed weak section, and has the smallest heat-seal width of any section of the automatically ventilated packaging bag 10. In addition, the ventilation section 30 has a maximum protruding position that is equal to or greater than the maximum width of the side gradually tapering seal section 20 (maximum side heat-seal width W4 ) toward the center of the packaging bag 10. As a result, the ventilation portion 30 is more likely to be subjected to the internal pressure during thermal expansion first. In other words, it is the first to be subjected to the force that tries to separate the heat-sealed side portions from each other. Therefore, the adhesion between the films of the ventilation portion 30 is efficiently broken.

[0027] As shown in FIG. 3 , the exhaust passage section 40 is a portion of the exhaust-side edge section 12 behind (outside of) the ventilation section 30 where the film bodies are not heat-sealed to each other. When the ventilation section 30 is destroyed, the exhaust passage section 40 allows water vapor inside the bag to pass through and be exhausted to the outside of the bag. The exhaust passage section 40 may also include a pressure-sealed section 41 that presses the overlapping film bodies together. The pressure-sealed section 41 seals the overlapping film bodies without heat sealing, thereby closing the exhaust passage section 40 before thermal expansion. This makes it difficult for foreign matter to enter the exhaust passage section 40. Furthermore, the pressure-sealed section 41 is easily released from the pressure when the ventilation section 30 is destroyed by thermal expansion. Therefore, the exhaust passage section 40 is opened in conjunction with the destruction of the ventilation section 30, allowing efficient exhaust.

[0028] As shown in FIG. 4 , the open-side edge portion 13 includes a protrusion 50 and an opening indication portion 51. The protrusion 50 is formed by heat-sealing and protruding in an arc shape toward the center in a shape corresponding to the ventilation portion 30 and the exhaust passage portion 40 of the exhaust-side edge portion 12. The protrusion 50 is formed to concentrate the internal pressure during thermal expansion toward the opposing exhaust-side edge portion 12. To effectively concentrate the internal pressure, the protrusion 50 is formed near the opposing position of the ventilation portion 30. If the protrusion 50 is formed downward from the opposing position, internal pressure will be more likely to be applied to the downward side of the ventilation portion 30, causing the ventilation portion 30 to break more quickly. If the protrusion 50 is formed symmetrically to the ventilation portion 30, the appearance will be better.

[0029] The opening instruction portion 51 is a portion for identifying the opening start position for cutting open the upper side of the packaging bag 10 when opening it to remove the contents. The opening instruction portion 51 is formed of an appropriate easy-opening means such as a cut or a notch. When opening the packaging bag 10, the upper part of the packaging bag 10 is cut open and the upper opening 15 is opened by pinching the top and bottom of the opening instruction portion 51 with the left and right fingers and tearing it. Furthermore, the opening instruction portion 51 is not formed on the exhaust side edge portion 12, but is formed on the protruding portion 50 of the opposing open side edge portion 13. This is because steam is discharged through the exhaust passage portion 40 of the exhaust side edge portion 12 when heated, so by forming the opening instruction portion 51 on the open side edge portion 13, it is made clear that opening should be done while avoiding the exhaust passage portion 40, and this prevents fingers from being exposed to steam passing through the exhaust passage portion 40, allowing the packaging bag 10 to be opened safely and easily.

[0030] Furthermore, as shown in FIG. 4, it is preferable to form a concave-convex portion 70 on the protrusion 50 to indicate the opening instruction portion 51. The concave-convex portion 70 can be formed by creating a depression or piercing the overlapping film body with a needle or the like, or by molding it with a stamping die such as an embossing process. By forming the concave-convex portion 70, the position of the opening instruction portion 51 can be easily and clearly grasped. It is also more preferable to make the concave-convex portion 70 into a Braille display portion 80 that displays "cut" or "cut edge" in Braille. The Braille display portion 80 allows visually impaired people to easily and clearly grasp the opening start position indicated by the opening instruction portion 51, thereby improving handling safety.

[0031] Additionally, a side gradually increasing seal portion 22 is formed on the open-side side edge portion 13. The side gradually increasing seal portion 22 is a heat-sealed portion that increases in heat seal width W6 from the bottom edge portion 14 toward the upper opening 15, connecting to the protrusion 50. The side gradually increasing seal portion 22 has a shape in which the heat seal width W6 increases as it connects to the protrusion 50, and therefore acts to concentrate the internal pressure during thermal expansion toward the opposing exhaust-side side edge portion 12. The inclination angle of the side gradually increasing seal portion 22 is desirably approximately 15 to 21 degrees, and preferably approximately 19 degrees.

[0032] In addition, as shown in FIG. 5, the ventilation portions 30 of the both side portions 11 and the protruding portions 50 are connected to the upper opening 15 side. Heat seal width The automatically ventilated packaging bag 10A can be formed with gradually increasing upper side edge seal portions 60, 60. In the gradually increasing upper side edge seal portion 60, an inner edge portion 61 extending from the side of the upper opening 15 to the ventilation portion 30 (protrusion 50) protruding into the bag is formed in an inclined shape toward the inside of the bag. Therefore, when the packaging bag 10A is placed upright, the contents do not accumulate above the ventilation portion 30 or the protrusion 50 but fall into the bag, preventing some of the contents from spilling or sticking to fingers when the top of the packaging bag 10 is torn open.

[0033] Next, using Figure 6, we will explain how the automatic venting packaging bag 10 of the present invention deforms when heated and expanded. When the automatic venting packaging bag 10 of the present invention is heated, water vapor Vp (indicated by the bold dotted arrow) generated from the contents of the packaging bag 10 fills the bag, causing it to expand. At this time, because the side edge tapering seal portion 20 and the side edge gradually increasing seal portion 22 are formed on both side edges 11 of the packaging bag 10, the amount of pressure applied to the film varies depending on the heat seal width. Therefore, the volume of the side edge tapering seal portion 20 side is larger than the volume of the side edge gradually increasing seal portion 22 side. Therefore, expansion on the exhaust side edge portion 12 side is more pronounced. On the exhaust side edge portion 12 side of the automatic venting packaging bag 10, the ventilation portion 30 is the portion that is most inward. Therefore, water vapor pressure is easily applied to the ventilation portion 30. Because the internal pressure generated by water vapor at this point is lower than the heat seal strength of each portion, the heat seal portion does not break.

[0034] The ventilation section 30 has the narrowest heat seal width of any section of the automatically ventilated packaging bag 10, intentionally weakening the heat seal strength. When the internal pressure concentrated around the ventilation section 30 increases and exceeds the heat seal strength of the ventilation section 30, the heat seal (welding) of the ventilation section 30 breaks, opening the ventilation section 30 and connecting it to the exhaust passage section 40. Once the ventilation section 30 is opened, the pressure inside the bag increases and expands, allowing water vapor to be smoothly exhausted from the ventilation section 30 through the exhaust passage section 40, immediately reducing the internal pressure. Water vapor continues to be exhausted until the internal pressure is approximately balanced with the external air pressure. This reduction in the internal pressure within the packaging bag 10 prevents the internal pressure from exceeding the heat seal strength of sections other than the ventilation section 30, and therefore the heat seals of sections other than the ventilation section 30 are not broken.

[0035] Furthermore, the protrusions 50 formed on the open-side side edge 13 are heat-sealed so as to protrude toward the center at a position opposite the vent section 30, thereby guiding the increased internal pressure toward the vent section 30. This provides an additional internal pressure induction in addition to the internal pressure induction by the side tapering seal section 20, so that the internal pressure is well concentrated around the vent section 30. Therefore, the automatically venting packaging bag 10 of the present invention can smoothly and safely achieve expansion due to the generation of steam and then exhaust when cooked.

[0036] In this way, the automatic venting packaging bag 10 of the present invention has a structure in which the configuration of both side edges 11 causes significant expansion on the exhaust side edge 12 side, so excessive expansion and bursting are avoided and the internal water vapor is safely exhausted.

[0037] As shown and described above, the automatic venting packaging bag of the present invention is a vertically-positioned packaging bag having a tapered seal portion, a vent portion, and an exhaust passage portion formed on the exhaust-side side edge, and a protrusion and an opening indicator portion formed on the open-side side edge. Therefore, the structure is significantly simpler than conventional bags, making manufacturing easier, improving manufacturing efficiency, and reducing manufacturing costs. Furthermore, the tapered seal portion on the exhaust-side side edge and the protrusion or increasing seal portion on the open-side side edge allow water vapor generated during thermal expansion to be efficiently concentrated toward the vent portion. This allows water vapor to be properly and safely vented from the vent portion.

[0038] Furthermore, the protrusions are formed with uneven surfaces by embossing, making it easier to grasp the position of the opening instruction section, so that the package can be opened without bringing fingers close to the exhaust passage section, allowing for safe and secure opening and not restricting package design. [Industrial Applicability]

[0039] The automatic venting packaging bag of the present invention is a vertically placed packaging bag that has a simpler structure than conventional bags, is capable of improving manufacturing efficiency and cost, is capable of properly and effectively venting water vapor when heated and expanded, and makes it easy to determine the opening start position. Therefore, it is a promising alternative to commercially available cooking-compatible packaging bags. [Explanation of symbols]

[0040] 10 Automatic ventilated packaging bag 11 Side part 12 Exhaust side edge 13 Open side side part 14 Bottom 15 Top opening 16 Top 20 Side tapering seal 21 Side edge fixed width seal 22 Side edge gradual increase seal part 30 Ventilation section 40 Exhaust passage 41 Crimp sealing part 50 protruding part 51 Opening instruction section 60 Upper side gradual increase seal part 61 Inner edge of upper incremental seal 70 Uneven part 80 Braille display unit W1 Heat seal width of tapered seal on side W2 Heat seal width of fixed width seal on side edge W3 Minimum heat seal width of tapered seal on side W4 Maximum heat seal width of tapered seal on side W5 Heat seal width of ventilation area W6 Heat seal width of gradually increasing side seal

Claims

1. A vertically placed packaging bag is formed by heat-sealing both side edges and a bottom edge of overlapping film bodies, and has a top opening that is heat-sealed to form the top edge after the contents are placed inside, The exhaust side edge portion, which is one of the both side edges, has The packaging bag is provided with a side edge tapering seal portion having a shape in which the heat seal width (W1) decreases from the bottom edge side toward the top opening and an inclination angle of 3 to 11 degrees, and a ventilation portion having a heat seal width (W5) narrower than the side edge minimum heat seal width (W3) of the heat seal width of the side edge tapering seal portion and heat-sealed in an arc shape protruding toward the center of the packaging bag, and an exhaust passage portion that is not heat-sealed between the film bodies is provided behind the ventilation portion in the exhaust side side portion, The other of the two side portions, that is, the open side portion, is A protruding portion is provided near the opposing position of the intended ventilation portion and is heat-sealed so as to protrude toward the center, and a side gradually increasing seal portion is provided at the side edge of the open side, which is connected to the protruding portion from the bottom edge side and has a shape in which the heat seal width (W6) increases and has an inclination angle of 15 to 21 degrees, and an opening instruction portion is formed on the protruding portion to specify the opening start position for cutting open the upper side of the packaging bag when removing the contents. An automatic ventilation packaging bag characterized by the above.

2. 2. The automatic ventilation packaging bag according to claim 1, further comprising upper side gradually increasing seal portions on both side edges, each of which is connected to the ventilation portion and the protruding portion from the upper opening side and has a heat seal width that increases.

3. 2. The automatic ventilation packaging bag according to claim 1, wherein the protruding portion has a concave-convex portion formed thereon to indicate the opening indication portion.

4. 4. The automatic ventilation packaging bag according to claim 3, wherein the concave and convex portions form a Braille display portion.

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