Packaging bags

Abstract

To provide a back-sealed bag-shaped packaging bag having an automatic steaming function that prevents a steaming portion from being unintentionally broken during distribution and that can smoothly release steam when heated. [Solution] A packaging bag 1 in the form of a back-sealed bag has a bag body 10 formed by laminating a plastic resin film or a laminate thereof and having a storage section 15 formed inside, and an arch-shaped non-sealed section 13 connected to the storage section is formed in the back-sealed section 11, and a section intended for steam passage is formed on the side of the non-sealed section that faces the bag body when the back-sealed section covers the bag body.

Description

[Technical Field]

[0001] The present invention relates to a back-sealed bag-shaped packaging bag having an automatic steam-passing function that automatically releases steam generated when the contents are heated. [Background technology]

[0002] Packaging bags used for heating contents are known. These packaging bags may be provided with a steam passage section for discharging water vapor generated from the contents when heated to the outside of the packaging bag. Patent Document 1 discloses an example of a packaging bag including a steam passage section. A sheet constituting this packaging bag is provided with a steam passage section having low strength so that it breaks when pressure inside the packaging bag increases. When this packaging bag is heated by a heating means such as a microwave oven, the sheet expands due to water vapor generated from the contents, and the steam passage section breaks as the sheet expands, allowing water vapor inside the packaging bag to be discharged from the broken section.

[0003] However, in the packaging bag of Patent Document 1, if an external force is applied to the packaging bag during the distribution process, such as during transportation, or if the packaging bag is pulled by a consumer when handling it, the intended steam-passing portion may be unintentionally ruptured, and the function of the intended steam-passing portion may be impaired.

[0004] One type of packaging bag known as a back-sealed bag 4 is shown in Figure 7, which is made by sealing a single piece of film back to back to form a tube, then gluing and cutting both ends of the tube to a specified length. This type of packaging bag is also called a palm-sealed bag or a pillow bag. The back-sealed portion becomes a back-sealed portion 21, which protrudes from the bag body across the bonded seal portions 12 at both ends. In its normal state, the protruding back-sealed portion 21 folds along the bag body and covers it in a configuration 21'.

[0005] When forming a steam-passing portion in such a back-sealed bag, in order to prevent the above-mentioned unintended rupture, the steam-passing portion 14 is formed in an area of ​​the bag body 20 that is covered by the back seal portion 21 so that the steam-passing portion 14 is not exposed. However, with this structure, when the bag is heated by a heating means such as a microwave oven to heat the contents 16 and the bag expands, the back seal portion 21 is pressed tightly against the bag body 20 without any gaps, as shown in Figure 8, a schematic cross-sectional view taken along line DD, and the expansion causes the steam-passing portion 14 to rupture, forming an opening 14' that is blocked by the back seal portion 21. This prevents the smooth release of steam 17 generated from the contents 16, etc., and can cause the internal pressure to increase too much, potentially resulting in the bag bursting. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3942709 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, an object of the present invention is to provide a packaging bag having a back-sealed bag shape, which has an automatic steam-passing function that prevents the steam-passing portion from being unintentionally ruptured during distribution, etc., and allows smooth release of steam when heated. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a packaging bag in the form of a back-sealed bag, which has a bag body formed with a storage section inside by laminating a plastic resin film or a laminate thereof, and is characterized in that an arch-shaped non-sealed section communicating with the storage section is formed in the back-sealed section, and a section intended for steam passage is formed in the part of the bag body that is covered by the back-sealed section.

[0009] The present invention also provides a packaging bag in the form of a back-sealed bag, having a bag body formed with a storage compartment inside by laminating a plastic resin film or a laminate thereof, characterized in that an arch-shaped non-sealed section communicating with the storage compartment is formed in the back-sealed section, and a steam-passing section is formed in the non-sealed section on the side facing the bag body when the back-sealed section is placed over the bag body.

[0010] The present invention also provides a packaging bag in the form of a back-sealed bag, having a bag body formed with a storage section inside by laminating a plastic resin film or a laminate thereof, characterized in that the back seal is embossed and a steam-passing section is formed in the area of ​​the bag body that is covered by the back seal.

[0011] In the packaging bag, the portion intended for steam passage may be formed by scratching. [Effects of the Invention]

[0012] According to the present invention, [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic external view of an embodiment of a packaging bag of the present invention. [Figure 2] 1 is a cross-sectional schematic view of one embodiment of a packaging bag of the present invention. [Figure 3] FIG. 2 is a schematic external view of a second embodiment of the packaging bag of the present invention. [Figure 4] FIG. 2 is a cross-sectional schematic view of a second embodiment of the packaging bag of the present invention. [Figure 5] FIG. 10 is a schematic external view of a third embodiment of the packaging bag of the present invention. [Figure 6] FIG. 4 is a cross-sectional schematic view of a third embodiment of the packaging bag of the present invention. [Figure 7] FIG. 1 is a schematic view showing the appearance of a conventional packaging bag. [Figure 8] FIG. 1 is a cross-sectional view of a conventional packaging bag. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments described below. Note that, in the following, the same reference numerals will be used to designate equivalent components, and their description may be omitted.

[0015] Fig. 1 is a schematic external view of one embodiment of the packaging bag of the present invention. Fig. 2 is a cross-sectional schematic view taken along line AA. The packaging bag 1 of the present invention has a shape generally referred to as a back-sealed bag, in which a single plastic film or a laminate thereof is sealed back to back to form a tube, and a predetermined length of the tube is bonded at seals 12 at both ends to form a bag body 10 having a storage compartment 15 inside. The back-sealed portion becomes back-sealed portion 11, which protrudes from bag body 10 across both bonded ends. In its normal state, the protruding back-sealed portion 11 falls along bag body 10 and covers the bag body 10 in a configuration 11'.

[0016] An arch-shaped non-sealed portion 13 is formed in a portion of the back seal portion 11 that is not sealed. There is no boundary or the like between the internal space of the non-sealed portion 13 and the storage portion 15, and the vapor passage portion 14 is formed in a portion of the bag body 10 that is covered by the back seal portion 11. Therefore, the vapor passage portion 14 is normally covered by the back seal portion 11. The vapor passage portion 14 can be formed by applying any known flaw processing method without any particular limitation, and is a weakened portion formed, for example, by blade processing, laser processing, half-cut processing, or the like.

[0017] Therefore, under normal conditions, the portion intended for steam passage, which is a fragile processed portion, is not exposed, and there is no risk of it coming into contact with other items and being torn during the distribution process, etc. Furthermore, even if, for example, adhesive tape is wrapped around multiple packaging bags 1 to bundle them together, the adhesive tape is not attached directly to the portion intended for steam passage, and there is no risk of the consumer accidentally torn the portion intended for steam passage when peeling off the adhesive tape.

[0018] The plastic film constituting the packaging bag 1 is not particularly limited, but examples include biaxially oriented nylon film (ONY), biaxially oriented polypropylene film (OPP), biaxially oriented polyester film (PET), unstretched nylon film (NY), and unstretched polypropylene film (PP). When a laminate is used, for example, a sealant layer may be laminated on each of the above plastic films. The sealant layer may be a layer of various resins with heat-sealing properties, such as polyolefin (polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), ethylene-acrylate copolymer, ionomer, ethylene-propylene copolymer, etc.), polyester, or acrylic copolymer. Suitable examples include, but are not limited to, low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE). The above films may be used alone or in various combinations.

[0019] Furthermore, layers other than those described above may be provided depending on the properties and use of the contents, and examples thereof include, but are not limited to, a barrier layer, a light-shielding layer, a stain-proof layer, and a printed layer.

[0020] When contents 16 are placed in packaging bag 1 and heated in a microwave oven, as shown in the lower diagram of Figure 2, the moisture in the contents etc. evaporates, generating steam 17, which causes storage section 15 to expand and the internal pressure to increase. As a result, the internal space of non-sealed section 13 also expands together with storage section 15, causing back-attached sealed section 11 to naturally rise and exposing steam-passing section 14. As the internal pressure increases further, steam-passing section 14, which is a weakened section, automatically ruptures to form opening 14', and steam 17 is released, reducing the internal pressure and preventing packaging bag 1 from bursting, while maintaining an appropriate internal pressure for steam cooking.

[0021] By forming the arch-shaped non-sealed portion 13, the back-attached sealed portion 11 rises up properly when heated in a microwave oven, and the opening 14' is exposed, allowing the steam 17 to be smoothly discharged.

[0022] Fig. 3 is a schematic external view of a second embodiment of the packaging bag of the present invention. Fig. 4 is a cross-sectional schematic view taken along line BB. The packaging bag 2 in this embodiment can be equivalent to the above-described embodiments in terms of basic configuration and materials, but the intended steam passage portion 14 is formed on the side of the non-sealed portion 13 that falls along the bag body 10 and covers the bag body 10 in a normal state. In other words, the intended steam passage portion 14 is provided on the side that faces the bag body 10 when the back seal portion 11 is in the state 11' that covers the bag body 10.

[0023] When contents 16 are placed in packaging bag 2 and heated in a microwave oven, similar to the above-described embodiment, the moisture in the contents etc. evaporates, generating steam 17, causing storage section 15 to expand, expanding the internal space of non-sealed section 13 and causing back-attached sealed section 11 to rise, exposing steam-passing section 14 formed in non-sealed section 13. As the internal pressure further increases, steam-passing section 14 automatically ruptures to form opening 14', and steam 17 is released to reduce the internal pressure, preventing packaging bag 1 from bursting and maintaining an appropriate internal pressure for steam cooking.

[0024] The steam passage portion 14 formed in the arch-shaped non-sealed portion 13 is exposed when the back-attached sealed portion 11 stands up during heating in a microwave oven, and remains exposed even when it becomes an opening 14', allowing the steam 17 to be smoothly discharged.

[0025] Fig. 5 is a schematic external view of a third embodiment of the packaging bag of the present invention. Fig. 6 is a cross-sectional schematic view taken along line CC. The packaging bag 3 in this embodiment can be equivalent to the above-described embodiments in terms of basic configuration and materials, but the back seal portion 11 is embossed to have an uneven shape. The steam-passing portion 14 is formed in a portion of the bag body 10 that is covered by the back seal portion 11. Therefore, the steam-passing portion 14 is normally covered by the back seal portion 11.

[0026] When contents 16 are stored in packaging bag 3 and heated in a microwave oven, as in the above-described embodiment, the moisture in the contents etc. evaporates, generating steam 17, causing storage section 15 to expand and enlarge, and as the internal pressure increases further, fragile processed section 14, which is intended for steam passage, automatically breaks to form opening 14', and steam 17 is released, reducing the internal pressure and preventing packaging bag 3 from bursting, while maintaining an appropriate internal pressure to allow steam cooking.

[0027] Unlike the above-described embodiments, the back seal portion 11 does not clearly stand up, but since the back seal portion 11 is embossed to form the unevenness 18, the back seal portion is not pressed tightly against the bag body, as in conventional packaging bags, leaving no gaps, and the water vapor 17 that sprays out from the opening 14' is released by passing through the spaces created in the recesses of the unevenness 18, allowing the water vapor 17 to be smoothly discharged.

[0028] As described above, in the packaging bag of the present invention, the steam-passing portion, which is a fragile processed portion, is normally covered by the back seal portion, so there is no risk of it being unintentionally ruptured during distribution or when handled by consumers.On the other hand, when heated in a microwave oven, the opening formed by the rupture of the steam-passing portion is not blocked by the back seal portion, so a packaging bag can be provided that allows water vapor to be released smoothly. [Example]

[0029] The present invention will be described in more detail below with reference to examples.

[0030] <Packaging bag composition> Laminate: Outer: PET (12 μm) / Inner: LLDPE (40 μm) Size: 140mm high, 100mm wide Sealing section: Heat seal both ends in the vertical direction at a width of 10 mm. -Spine sticker: Stick it on with a width of 10 mm so that it is roughly in the center of the left and right directions. - Steam passage area: Scratches are made in the specified shape at the specified location on the PET film.

[0031] <Evaluation method> (1) Distribution Test -One commercially available hamburger steak (80g) was filled into each packaging bag, sealed, and 50 bags were packed into a cardboard box and cooled to -15°C. The four cardboard cases were subjected to a vibration test (JIS Z0232:2004 (Level 1)) and a drop test (JIS Z0200:2013 (Level 1)). Count the number of damaged packaging bags. (2) Range up test 20 bags were made by filling one commercially available hamburger steak (80g) into each bag and sealing it. These were then heated in a microwave oven (500W) for 3 minutes and visually inspected to ensure they had been properly steamed.

[0032] Example 1 -Type of back seal: There is an arched non-sealed section. Location of scratch processing: The area that is covered by the back seal of the bag body. Scratch shape: 20mm long, straight line. The results are summarized in Table 1.

[0033] <Example 2> -Type of back seal: There is an arched non-sealed section. Location of scratch processing: The side of the back seal facing the non-sealed part of the bag body. Scratch shape: 20mm long, straight line. The results are summarized in Table 1.

[0034] Example 3 -Back seal: Embossed, no non-sealed areas. Location of scratch processing: The area that is covered by the back seal of the bag body. Scratch shape: 20mm long, straight line. The results are summarized in Table 1.

[0035] <Comparative Example 1> -Type of back seal: No non-sealed areas. Location of scratch processing: The area that is covered by the back seal of the bag body. Scratch shape: 20mm long, straight line. The results are summarized in Table 1.

[0036] <Comparative Example 2> -Type of back seal: No non-sealed areas. Location of scratch processing: Approximately in the center of the bag body (opposite the side covered by the back seal). - Shape of scratch processing: 5mm diameter holes. The results are summarized in Table 1.

[0037] [Table 1]

[0038] In each example, there was no breakage in the flow test, and good results were obtained. Steaming by microwave heating was also performed properly. On the other hand, in Comparative Example 1, breakage occurred in the flow test, and some samples could not be properly steamed, resulting in poor results overall. In Comparative Example 2, steaming was performed properly, but many breakages occurred in the flow test. [Explanation of symbols]

[0039] 1, 2, 3...Packaging bag 10. Bag body 11 Back sticker 12 Seal part 13. Non-sealed part 14. Steam passage section 14´··· opening 15 Storage area 16...Contents 17. Water vapor 18...Unevenness

Claims

1. A packaging bag in the form of a back-sealed bag having a bag body formed by laminating a plastic resin film or a laminate thereof and having a storage section formed inside, characterized in that an arch-shaped non-sealed section communicating with the storage section is formed in the back-sealed section, and a steam-passing section is formed on the side of the non-sealed section that faces the bag body when the back-sealed section is placed over the bag body.

2. 2. The packaging bag according to claim 1, wherein the steam passage portion is formed by scratching.

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