JP7758911B2 - Automatic Ventilated Packaging Bag - Google Patents

Description

This invention relates to a vertically placed, automatically ventilated packaging bag that automatically releases water vapor generated from the contents when the contents are heated together with the packaging bag, preventing the packaging bag from bursting.

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 grown even more than before, particularly due to a decline in the number of people per household and calls for restaurants to reduce cooking costs. 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 containers have 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.

Previously, to prevent the container (packaging bag) from bursting due to water vapor, users had to puncture it before heating, which was time-consuming. While some containers (packaging bags) exist with pre-made holes, the airtightness of the container itself is not particularly good, and they are primarily used to package 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 automatic vents in part of the container or packaging bag have been proposed. Although the automatic vents are always closed, they are the first to open when heated due to the expanding 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.

The inventor has developed an automatic venting packaging bag that has a simpler structure than conventional bags and is capable of properly and safely venting water vapor (see, for example, Patent Document 1). This automatic venting packaging bag has side edges with fixed-width sealed sections where the heat seal width is constant from the open mouth to the bottom, and side edges with gradually tapering sealed sections where the heat seal width decreases from the fixed-width sealed sections to the bottom. The bottom edge has a gradually tapering bottom sealed section where the heat seal width decreases from both ends of the bottom edge to the center. The center of the bottom edge has a ventilation section that is heat-sealed in an arc shape toward the center of the packaging bag and has a heat seal width narrower than the heat seal width of the gradually tapering bottom sealed section. Additionally, an exhaust passage section that is not heat-sealed between the film bodies is provided behind the ventilation section at the bottom edge.

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. The expansion force of this steam is used to concentrate 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 outside the bag.

In recent years, there has been growing 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 upright in a microwave oven 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 creates a risk of people bringing their fingers close to the vent position when opening the bag. While the opening position is clearly indicated, this has led to problems such as limitations on package design. Therefore, there is a need for an automatically vented vertically-positioned packaging bag that is simple and does not require a complex structure, yet is capable of good ventilation and allows the opening position to be easily identified.

Patent No. 6561035

The present invention has been developed in consideration of the above points, and provides a vertically-positioned automatic venting packaging bag that is capable of effective ventilation with a simpler structure than conventional bags, and that allows the opening position to be easily and clearly identified, making it safe to open.

That is, the first invention is a vertical-type packaging bag having an upper opening formed by heat-sealing both side edges and a bottom edge of overlapping film bodies, and heat-sealed to form the upper edge after the contents are placed inside, and the exhaust side edge, which is one of the both side edges , is provided with a side edge gradually tapering seal part having a shape in which the heat seal width (W1) decreases from the bottom edge side toward the upper opening and an inclination angle of 3 to 11 degrees , and a ventilation section which is heat-sealed and protrudes in an arc shape toward the center of the packaging bag and has a heat seal width (W5) narrower than the side edge minimum heat seal width (W3) of the heat seal width of the side edge gradually tapering seal part, and an exhaust passage section which is not heat-sealed between the film bodies is provided behind the ventilation section at the exhaust side edge, The automatic ventilation packaging bag is characterized in that the other of the two side edges, the open side edge, is provided with a protrusion that protrudes toward the center near the opposing position of the intended ventilation section and is heat-sealed, and the open side edge is provided with a side edge gradually increasing seal section that is connected to the protrusion from the bottom edge side and has a shape that increases the heat seal width (W6) and has an inclination angle of 15 to 21 degrees, and the protrusion is formed with an opening instruction section that specifies the opening start position for cutting open the upper side of the packaging bag when removing the contents.

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The second invention relates to the first invention, an automatically ventilated packaging bag having 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 that increase the heat seal width.

The third invention relates to an automatic ventilation packaging bag according to the first invention, in which the protruding portion has an uneven portion formed thereon to indicate the opening indication portion.

The fourth invention relates to an automatic ventilation packaging bag according to the third invention, in which the braille display is formed by the uneven portion.

According to a first aspect of the present invention, the automatic ventilation packaging bag is a vertically placed packaging bag having an upper opening formed by heat-sealing both side edges and a bottom edge of overlapping film bodies, and which is heat-sealed to form the upper edge after the contents are placed inside, and the exhaust side edge, which is one of the both side edges , is provided with a side edge tapering seal part having a shape in which the heat seal width (W1) decreases from the bottom edge side toward the upper opening and an inclination angle of 3 to 11 degrees , and a ventilation section which has a heat seal width narrower than the minimum side heat seal width of the side edge tapering seal part and is heat-sealed in an arc shape protruding 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 intended ventilation section, and the other of the two side sections, the open side section, is provided with a protrusion that protrudes toward the center near the opposing position of the intended ventilation section and is heat-sealed, and the open side section is provided with a side gradually increasing seal section that is connected to the protrusion from the bottom side and has a heat seal width inclination angle of 15 to 21 degrees, and the protrusion is formed with an opening indicator section that specifies the opening start position for cutting open the upper side of the packaging bag when removing the contents, so that it is possible to achieve good exhaust with a simpler structure than conventional ones, and the opening position can be easily and clearly grasped, allowing for safe opening.

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According to the second aspect of the invention, the automatic venting packaging bag is similar to the first aspect in that it is provided with upper side gradually increasing seal sections on both sides that are connected from the upper opening side to the ventilation section and the protruding section, respectively, and that increase the heat seal width. This prevents the contents from accumulating above the ventilation section or the protruding section, making it less likely to spill when opened.

According to the third aspect of the invention, the automatic venting packaging bag is similar to the first aspect in that the protruding portion is formed with an uneven portion that indicates the opening instruction portion, making it easier and clearer to determine the opening start position.

According to the fourth invention, the automatic ventilation packaging bag of the third invention has a Braille display area formed by the uneven portion, making it easier and clearer for visually impaired people in particular to determine the opening start position.

1 is a front view of an automatic ventilation packaging bag according to an embodiment of the present invention; 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. 1 is a schematic diagram of the area around the exhaust side edge of the automatic ventilation packaging bag. FIG. 1 is a schematic diagram of the opening side edge portion of an automatic ventilation packaging bag. 1 is a schematic diagram of an automatic ventilation packaging bag having an upper gradually increasing seal portion formed therein. FIG. 1 is a conceptual diagram of the expansion of an automatic ventilated packaging bag.

The automatic ventilation packaging bag 10 according to one embodiment of the present invention shown in Figures 1 and 2 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 in a microwave oven (high-frequency range, microwave oven) as a whole. 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, there are no particular restrictions on the contents that can be filled, and it can also be used for foods with a lot of liquid.

The film body is typically a well-known retort packaging material. Examples of film bodies include biaxially oriented films made of polypropylene film, polyamide film, polyester film, ethylene-vinyl alcohol copolymer, etc., biaxially oriented polyester film with aluminum oxide vapor deposition, biaxially oriented polyester film with silica vapor deposition, oriented polymetaxylylene adipamide polyamide film, and microwave-safe heat-resistant films such as co-extruded laminates of these with nylon 6 or similar. These films are typically two- or three-layer laminates formed by laminating a sealant film, which contacts the contents and forms a mutually fused bond via heat sealing, with a polyamide or polyester resin film protecting the sealant film. The film body is selected based on a comprehensive consideration 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 of the packaging bag, the distribution route, and the distribution method. For example, for polypropylene films, products such as ZK93KM manufactured by Toray Advanced Film Co., Ltd. are used, and for polymetaxylylene adipamide-based polyamide stretched films, products such as SP-R manufactured by Mitsubishi Plastics, Inc. are used.

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

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

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 heat-sealed area 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 detract from the appearance and increase the amount of film used.

1 to 3, the ventilation section 30 is a heat-sealed section that extends upward from the center of the exhaust-side side edge 12 and has a heat-seal width W5 that is narrower than the minimum side heat-seal width W3 of the heat-seal width W1 of the side edge tapering seal section 20, and that protrudes in an arc shape toward the center of the packaging bag 10. When the automatically venting packaging bag 10 expands due to steam generated from the contents during cooking, the ventilation section 30 allows steam within the bag to be released.

As shown in FIG. 3 , the ventilation section 30 has a flat, trapezoidal shape. The ventilation section 30 is the first to break (rupture) the heat-sealed film seal during thermal expansion, allowing water vapor inside the bag to escape. The ventilation section 30 is an intentionally formed weak section, with the smallest heat-sealed width of any section of the automatically ventilated packaging bag 10. Furthermore, the ventilation section 30 is formed so that its maximum protrusion point is closer to the center of the packaging bag 10 than the maximum width of the gradually tapered side seal section 20 (maximum side heat-sealed width W4 ). This makes the ventilation section 30 the first to be subjected to internal pressure during thermal expansion. In other words, it is the first to experience the force that separates the heat-sealed edges. Therefore, the film seal at the ventilation section 30 is efficiently broken.

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

As shown in Figure 4, the open-side edge portion 13 has a protrusion 50 and an opening indicator 51. The protrusion 50 is heat-sealed to protrude in an arc toward the center in a shape corresponding to the ventilation section 30 and exhaust passage section 40 of the exhaust-side edge portion 12. The protrusion 50 is formed to concentrate internal pressure toward the opposing exhaust-side edge portion 12 during thermal expansion. To ensure good internal pressure concentration, the protrusion 50 is formed near the opposing position of the ventilation section 30. If the protrusion 50 is formed below the opposing position, internal pressure will be more likely to be applied to the downward side of the ventilation section 30, causing the ventilation section 30 to break more quickly. Forming the protrusion 50 symmetrically to the ventilation section 30 results in a better appearance.

The opening instruction section 51 is a section that identifies the opening start position for cutting open the upper side of the packaging bag 10 when opening it to remove the contents. This opening instruction section 51 is made of an appropriate easy-to-open means such as a cut or notch. When opening the packaging bag 10, the top 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 section 51 with the left and right fingers and tearing it. Furthermore, the opening instruction section 51 is not formed on the exhaust side edge section 12, but on the protrusion 50 of the opposing open side edge section 13. This is because steam is released through the exhaust passage section 40 of the exhaust side edge section 12 when heated. Therefore, by forming the opening instruction section 51 on the open side edge section 13, it is clear that opening should be done while avoiding the exhaust passage section 40. This prevents fingers from being exposed to steam passing through the exhaust passage section 40, allowing for safe and easy opening of the packaging bag 10.

Furthermore, as shown in Figure 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 using 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.

In addition, a gradually increasing side seal portion 22 is formed on the open side edge portion 13. The gradually increasing side 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 gradually increasing side 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 edge portion 12. The inclination angle of the gradually increasing side seal portion 22 is desirably approximately 15 to 21 degrees, and preferably approximately 19 degrees.

5, the automatically ventilated packaging bag 10A may have upper side gradually increasing seal portions 60 , 60 formed on the upper opening 15 sides of the ventilation portion 30 and the protruding portion 50 of both side edges 11. The upper side gradually increasing seal portion 60 has an inner edge 61 that slopes toward the inside of the bag and extends from the side of the upper opening 15 to the ventilation portion 30 (protruding portion 50). When the packaging bag 10A is placed upright, the contents do not accumulate above the ventilation portion 30 or the protruding portion 50 but fall into the bag, preventing the contents from spilling or sticking to fingers when the top of the packaging bag 10 is torn open.

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 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. As a result, 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 is not destroyed.

The ventilation section 30 has the narrowest heat seal width of any section of the automatically ventilated packaging bag 10, intentionally weakening its 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 via 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 prevents the heat seals of sections other than the ventilation section 30 from breaking.

In addition, the protrusion 50 formed on the open-side edge 13 is heat-sealed and protrudes toward the center at a position opposite the intended ventilation section 30, thereby guiding the increased internal pressure toward the intended ventilation section 30. This provides additional internal pressure guidance in addition to the internal pressure guidance provided by the side tapering seal section 20, effectively concentrating the internal pressure around the intended ventilation section 30. Therefore, the automatically venting packaging bag 10 of the present invention can smoothly and safely achieve both expansion due to the generation of steam and exhaustion during cooking.

In this way, the automatic venting packaging bag 10 of the present invention is designed so that the configuration of both side edges 11 allows for significant expansion on the exhaust side edge 12 side, preventing excessive expansion and bursting and allowing the internal water vapor to be safely vented.

As shown and described above, the automatic venting packaging bag of the present invention is a vertically-positioned packaging bag that has a tapered seal portion, a vent portion, and an exhaust passage portion formed on the exhaust side edge, and a protrusion portion and an opening indicator portion formed on the open 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 edge and the protrusion portion or increasing seal portion on the open 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.

Furthermore, the protruding portion is embossed to form unevenness, making it easier to identify the location of the opening instruction area. This means that the package can be opened without bringing your fingers close to the exhaust passage, allowing for safe and secure opening and eliminating restrictions on package design.

The automatic venting packaging bag of the present invention is a vertically placed packaging bag that has a simpler structure than conventional bags, improving manufacturing efficiency and costs. It can properly and effectively vent water vapor when heated and expanded, and the opening start position can be easily determined. Therefore, it is a promising alternative to commercially available cooking-compatible packaging bags.

10 Automatic ventilating packaging bag 11 Side edge portion 12 Exhaust side edge portion 13 Opening side edge portion 14 Bottom edge portion 15 Upper opening portion 16 Upper edge portion 20 Side edge gradual decrease seal portion 21 Side edge fixed width seal portion 22 Side edge gradual increase seal portion 30 Ventilation portion 40 Exhaust air passing portion 41 Pressure-sealed portion 50 Protruding portion 51 Opening indication portion 60 Upper side gradual increase seal portion 61 Inner edge portion of upper side gradual increase seal portion 70 Concave and convex portion 80 Braille display portion W1 Heat seal width of side edge gradual decrease seal portion W2 Heat seal width of side edge fixed width seal portion W3 Minimum heat seal width of side edge gradual decrease seal portion W4 Maximum heat seal width of side edge gradual decrease seal portion W5 Heat seal width of ventilation portion W6 Heat seal width of side edge gradual increase seal portion

Claims (4)

A vertically placed packaging bag having a top opening formed by heat-sealing both side edges and a bottom edge of overlapping film bodies, which 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
an automatically ventilated packaging bag comprising: a protruding portion that protrudes toward the center near a position facing the intended ventilation portion and is heat-sealed; a side edge gradually increasing seal portion that is connected to the protruding portion from the bottom edge side of the open side and has a shape that increases the heat seal width (W6) and has an inclination angle of 15 to 21 degrees; and an opening indicator portion that specifies the opening start position for cutting open the upper side of the packaging bag when removing the contents. The automatically ventilated packaging bag according to claim 1, further comprising upper side gradually increasing seal portions on both sides that are connected from the upper opening side to the ventilation portion and the protruding portion, respectively, and that increase the heat seal width. The automatic ventilation packaging bag according to claim 1, wherein the protruding portion has an uneven portion formed thereon to indicate the opening indication portion. The automatic ventilation packaging bag according to claim 3, wherein the uneven portion forms a Braille display portion.