Microwave packaging bag, method for manufacturing the same, and method for heating the same in a microwave oven.

Abstract

The present invention provides a microwave-safe packaging bag that prevents the opening and closing mechanism from being soiled by the contents before the packaging bag is opened, and also prevents leakage of the contents when the bag is tipped over during microwave heating. [Solution] A microwave-safe packaging bag 1 comprises a circumferential portion having a front portion and a back portion facing each other, and an opening / closing member 26 that reseals the contents by engaging a front-side engaging member and a back-side engaging member, wherein the front-side engaging member and the back-side engaging member are fixed to the inside of the front portion and the back portion, respectively, and are provided with an easy-peel portion 27 that seals the contents below the opening / closing member and prevents the contents from adhering to the opening / closing member, the front portion is provided with a gusset portion 10 formed by overlapping the inner surfaces of both side edges of the film, and the gusset portion is provided with a steam-venting seal portion 11 through which steam generated inside the packaging bag during heating is released.

Description

Technical Field

[0004] , , ,

[0006] , , ,

[0005] , , , ,

[0007] , , ,

[0001] The present invention relates to a packaging bag for a microwave oven, a method for manufacturing the same, and a method for heating the same in a microwave oven.

Background Art

[0002] Patent Document 1 discloses a retort pouch in which a zipper (opening / closing member) is not soiled when opened, the contents can be filled quickly, and further, the contents do not leak.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the retort pouch of Patent Document 1, the zipper (opening / closing member) is configured to continuously include a non-sealing portion that allows steam to pass in the vertical direction without being fixed to the side surface portion at one end in the width direction of the retort pouch.

[0005] However, in the retort pouch of Patent Document 1, since the retort pouch is not sealed at the non-sealing portion when heated in a microwave oven, there is a problem that liquid leakage easily occurs from the non-sealing portion when the retort pouch is laid on its side. <舍

[0006] The present invention has been made in view of such circumstances, and provides a packaging bag for a microwave oven in which the opening / closing member is not soiled by the contents before the packaging bag is opened, and further, leakage of the contents is suppressed when the packaging bag is laid on its side during microwave heating.

Means for Solving the Problems

[0007] According to the present invention, the following inventions are provided. [1] A microwave oven packaging bag made of a flexible film formed into a bag shape, the packaging bag comprising a circumferential portion having a front portion and a back portion facing each other, and an opening / closing member that reseals the contents by engaging a front-side engaging member and a back-side engaging member, the front-side engaging member and the back-side engaging member are fixed to the inside of the front portion and the back portion, respectively, and are provided with an easy-peel portion that seals the contents below the opening / closing member and prevents the contents from adhering to the opening / closing member, the front portion is provided with a gusset portion formed by overlapping the inner surfaces of both side edges of the film, and the gusset portion is provided with a steam-venting seal portion that releases steam generated inside the packaging bag when heated. A packaging bag according to [2][1], wherein the easy-peel portion is formed continuously with the front engagement member or the rear engagement member, and is joined at a heat-seal portion provided on the inside of the front portion and the rear portion that does not have the easy-peel portion continuously attached. A packaging bag according to [3] [1] or [2], wherein, in a cross-sectional view along the vertical direction of the packaging bag, the distance d4-d5, which is the distance d4 between the lower end of the easy-peel portion and the base of the gusset portion minus the length d5 ​​of the gusset portion, is 5 mm or less. A packaging bag according to any one of [4][1] to [3], wherein the circumferential portion is provided with an opening portion for opening the packaging bag by tearing the circumferential portion, and the opening / closing member is configured to open and close the opening formed when the packaging bag is opened at the opening portion. [5] A method for manufacturing a microwave oven packaging bag, the packaging bag comprising a circumferential portion having a front portion and a back portion facing each other, and an opening / closing member that reseals the contents by engaging a front-side engaging member and a back-side engaging member, wherein the front-side engaging member and the back-side engaging member are fixed to the inside of the front portion and the back portion, respectively, and are provided with an easy-peel portion that seals the contents below the opening / closing member and prevents the contents from adhering to the opening / closing member, the method comprising a sealing step of sealing the opening / closing member after filling the packaging bag with the contents, and an easy-peel portion joining step of joining the easy-peel portion at a heat-seal portion provided on the inside of the circumferential portion, wherein the sealing step and the easy-peel portion joining step are performed simultaneously. [6] A method for manufacturing a microwave oven packaging bag, wherein the packaging bag comprises a circumferential portion having a front portion and a back portion facing each other, and an opening / closing member that reseals the contents by engaging a front-side engaging member and a back-side engaging member, the front-side engaging member and the back-side engaging member are fixed to the inside of the front portion and the back portion, respectively, and are provided with an easy-peel portion that seals the contents below the opening / closing member and prevents the contents from adhering to the opening / closing member, the method comprising a filling step of filling the packaging bag with the contents, a sealing step of sealing the opening / closing member after the filling step, an easy-peel portion joining step of joining the easy-peel portion at a heat-seal portion provided on the inside of the circumferential portion, and an upper end joining step of joining the front portion and the back portion at the upper end of the packaging bag, the method wherein in the filling step, the tip of a filling nozzle that discharges the contents is positioned below the opening / closing member. A method for heating a packaging bag in a microwave oven as described in any one of items [7][1] to [4], wherein the packaging bag containing the contents is sealed at the start of microwave heating of the packaging bag. [Effects of the Invention]

[0008] In the packaging bag of the present invention, when unopened, an easy-peel section is provided continuously with the opening / closing member and positioned between the opening / closing member and the contents, thereby preventing the opening / closing member from becoming soiled by the contents. Furthermore, a steam-venting seal section is provided in the gusset section on the front, which allows steam generated inside the packaging bag during heating to be released. This prevents leakage of contents from the opening / closing member even when the bag is tipped over during microwave heating. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1A is a perspective view of the packaging bag 1 with its contents contained inside. Figure 1B is a perspective view of the packaging bag 1 when opened at the upper opening 25, and Figure 1C is a perspective view of the packaging bag 1 when opened at the lower opening 24. [Figure 2] This is a diagram showing packaging bag 1 in a plan view. [Figure 3] This is a perspective view of the bottom film 20a that constitutes the bottom surface 2. [Figure 4] Figures 4A to 4C are explanatory diagrams illustrating how the opening 22 of the packaging bag 1 is opened and closed by the opening / closing member 26. Figure 4A is a cross-sectional view of AA in Figure 2, Figure 4B is an enlarged view of area F in Figure 4A, and Figure 4C shows the opening / closing member 26 in Figure 4B in the open state. [Figure 5] Figure 5A is a side view of the peripheral wall film 40. Figure 5B shows the state after a portion of the peripheral wall film 40 has been cut. [Figure 6] Figure 6A shows the state after inserting the V-shaped bottom film 42 between the front film 43 and the back film 44. Figure 6B shows the state after welding the bottom film 42 to the front film 43 and the back film 44, respectively. [Figure 7] Figure 7A is a plan view showing that the contents Q are filled into the packaging bag 1, and Figure 7B is a plan view showing that the packaging bag 1 has been heat-sealed after the contents Q have been filled into it. [Figure 8] Figure 8A is a cross-sectional view of AA in Figure 7A, and Figure 8B is a cross-sectional view of BB in Figure 7B. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below. The various features shown in the embodiments below can be combined with each other. Furthermore, each feature can constitute an invention independently. In addition, any element not specified in the claims in the embodiments below is an optional element and can be omitted. Any number of zeros (for example, one or two) may be added to the end of the numerical values ​​disclosed in the following description. For example, one or two zeros may be added after "1.4" to make it "1.40" or "1.400".

[0011] 1. First Embodiment 1-1. Packaging bag 1

[0012] As shown in Figure 1A, the microwave packaging bag 1 of the first embodiment of the present invention is a microwave packaging bag made of a flexible film formed into a bag shape. The packaging bag 1 has a circumferential portion 21 having a front portion 3 and a back portion 4 that face each other and constitute the circumferential surface of the bag shape. The packaging bag 1 also has a bottom portion 2, and the circumferential portion 21 is provided so as to rise from the bottom portion 2.

[0013] Figure 2 shows the packaging bag 1 in a plan view. A plan view means that the packaging bag 1 is laid flat when it does not contain any contents, and is viewed from a direction perpendicular to the front portion 3 of the packaging bag 1. As shown in Figure 2, the packaging bag 1 is formed to be symmetrical with respect to the center line in the left-right direction. In this disclosure, the top, bottom, left, and right of Figure 2 are described as the top, bottom, left, and right of the packaging bag 1. Specifically, the bottom portion 2 side is the bottom, and the front portion 3 (and back portion 4) side relative to the bottom portion 2 is the top. Also, the left and right when the front portion 3 is positioned towards the viewer are the left and right of the packaging bag 1. Furthermore, the front portion 3 side is the front, and the back portion 4 side is the rear.

[0014] The front face portion 3 and the back face portion 4 are welded (heat-sealed) to each other at their left and right ends (hereinafter also referred to as side ends). The bottom face portion 2 is welded to the front face portion 3 and the back face portion 4. In this way, by welding the bottom face portion 2, the front face portion 3, and the back face portion 4 to each other, the film is formed into a bag shape. Further, the packaging bag 1 can stand on its own with the bottom face portion 2 facing downward.

[0015] More specifically, a side end welding portion 12 for welding the front face portion 3 and the back face portion 4 is provided at the side end of the packaging bag 1. Thereby, the front face portion 3 and the back face portion 4 are fixed in the front-rear direction. Further, a lower end welding portion 13 for welding the bottom face portion 2 and the front face portion 3, and the bottom face portion 2 and the back face portion 4 is provided at the lower end of the packaging bag 1. The lower end welding portion 13 is a welding portion provided on the lower end side of the center line E, and welds the bottom face portion 2 and the front face portion 3, and the bottom face portion 2 and the back face portion 4 at the side end and the lower end of the packaging bag 1.

[0016] As shown in FIG. 3, the packaging bag 1 is manufactured by inserting a bottom face film 20a bent in a V shape at the center line E between the front face portion 3 and the back face portion 4. Cutouts R are formed at both ends of the bottom face film 20a. At the cutouts R, the front face portion 3 and the back face portion 4 are directly welded, and a fixing portion 15 for fixing the front face portion 3 and the back face portion 4 in the front-rear direction is formed as shown in FIG. 2.

[0017] As shown in FIG. 2, an air pocket 14 is provided outside the gradient portion 13a of the lower end welding portion 13. The air pocket 14 is formed in a triangular shape and is a space where air that could not be completely discharged outside during the welding at the lower end welding portion 13 remains. By providing the air pocket 14, the residual air in the lower end welding portion 13 gathers in the air pocket 14, improving the welding strength.

[0018] As shown in FIG. 1A, when the contents are contained inside, the easy peel portion 27 is joined at the heat seal portion 28 inside the front face portion 3 or the back face portion 4, the opening and closing member 26 is closed, and the upper end welding portion 16 is provided at the upper end of the packaging bag 1, thereby sealing the packaging bag 1.

[0019] When opening the packaging bag 1, as shown in Figure 1B, the front portion 3 and back portion 4 can be torn in the left-right direction at the upper opening portion 25 to form the opening 22. Next, by opening the opening / closing member 26, the easy-peel portion 27, which is continuously formed on the opening / closing member 26, is pulled, and the joint between the front portion 3 and the easy-peel portion 27 at the heat-seal portion 28 is peeled away. Next, the necessary ingredients are placed into the contents Q inside the packaging bag 1. After that, the opening / closing member 26 is engaged to close the opening of the packaging bag 1, and the packaging bag 1 may be placed in a microwave oven for heating and cooking.

[0020] The packaging bag 1 comprises an upper cut-off section 5 and a lower main body section 6, with the lower opening section 24 as the boundary. By tearing the front section 3 and back section 4 in the left-right direction at the lower opening section 24 and separating the cut-off section 5, an opening 7 is formed as shown in Figure 1C. The main body section 6 can also be used as tableware when eating the contents of the packaging bag 1.

[0021] As shown in Figure 1A, the front portion 3 is provided with a gable portion 10. The gable portion 10 is formed by overlapping and welding the inner surfaces of both side edges of the film that make up the upper and lower parts of the front portion 3. In this embodiment, the lower opening portion 24 and the upper opening portion 25 are provided on both the front portion 3 and the back portion 4 so as to extend across the packaging bag 1 in the left-right direction, at positions closer to and further from the bottom portion 2 than the gable portion 10, respectively.

[0022] In this embodiment, the lower opening section 24 includes a tear-start section 24a, which serves as the starting point for tearing the front section 3 and the back section 4, and an easy-tear section 24b. Similarly, the upper opening section 25 includes a tear-start section 25a and an easy-tear section 25b. The tear-start sections 24a and 25a are parts that facilitate tearing the front section 3 and the back section 4, and are formed, for example, by notches or cuts. The tear-start section 24a may be provided at one end of the lower opening section 24, or at both ends. Similarly, the tear-start section 25a may be provided at one end of the upper opening section 25, or at both ends. Note that the tear-start sections 24a and 25a are optional.

[0023] In the easy-tear sections 24b and 25b, for example, a portion of the film constituting the front section 3 and the back section 4 is treated with an easy-tear process. In this embodiment, perforations are applied as the easy-tear process in the easy-tear sections 24b and 25b. The perforations may be formed along the extending direction of the lower opening section 24 and the upper opening section 25.

[0024] As shown in Figure 2, a steam vent seal portion 11 is formed in the packaging bag 1. The steam vent seal portion 11 is provided in the girth portion 10. The steam vent seal portion 11 is a welded portion with lower welding strength compared to the side end weld portion 12, the lower end weld portion 13, and the upper end weld portion 16. When the packaging bag 1 is heated, the steam generated inside increases the internal pressure inside the packaging bag 1, and a steam passage is formed accordingly. The steam inside the packaging bag 1 is discharged to the outside through the steam vent seal portion 11.

[0025] The packaging bag 1 is provided with an easy-peel section 27 continuously below the opening / closing member 26, and the sealant layer of the easy-peel section 27 (in this embodiment, the layer located closest to the heat-seal section 28) may be made of, for example, an easy-peel resin. The easy-peel resin preferably has cohesive failure properties. The easy-peel resin is made of, for example, two or more heat-sealable resins and is a resin capable of forming a weak seal such that the peel strength according to JIS K6854 is generally less than 10 N / 15 mm width. In one example, the easy-peel resin is made of a mixed resin of polyethylene (PE) resin and polypropylene (PP) or polybutene (PB) resin. The easy-peel section 27 is for sealing the cooking liquid below the opening / closing member 26 in order to prevent the cooking liquid inside the packaging bag 1 from coming into contact with the opening / closing member 26. Therefore, the easy-peel portion 27 is formed, for example, continuously from the lower end of the base portion 26a1 of the front engaging member 26a, and is joined by a wavy heat-seal portion 28 located inside the rear portion 4 and below the lower end of the base portion 26b1 of the rear engaging member 26b. Alternatively, the easy-peel portion 27 may be formed continuously from the lower end of the base portion 26b1 of the rear engaging member 26b, and is joined by a wavy heat-seal portion 28 located inside the front portion 3 and below the lower end of the base portion 26a1 of the front engaging member 26a. Furthermore, the heat-seal portion 28 is not limited to being formed in a wavy shape, but may be formed continuously, for example, in a straight line.

[0026] The heat-sealed portion 28 is located, for example, on the side of the front portion 3 and the back portion 4 where the girdle portion 10 is not provided (in this embodiment, the back portion 4). That is, the heat-sealed portion 28 is formed by heat sealing from the side where the girdle portion 10 is not provided (in this embodiment, the back portion 4 side).

[0027] The opening / closing member 26 is configured to open and close the opening 22 formed when the packaging bag 1 is opened at the upper opening portion 25. The opening / closing member 26 is located between the opening 22 and the grommet portion 10 in the vertical direction. Figures 4A to 4C are explanatory diagrams of how the opening 22 of the packaging bag 1 is opened and closed by the opening / closing member 26, and the upper ends of the front portion 3 and the back portion 4 in the figures coincide with the location where the easy-tear portion 25b is formed. Also, the position J shown in Figure 4B indicates the position of the lower end of the upper opening portion 25 in the vertical direction (in this embodiment, the position J of the lower end of the tear-start portion 25a shown in Figure 2). The opening / closing member 26 includes a front-side engaging member 26a and a back-side engaging member 26b that can engage with each other. The base portion 26a1 of the front-side engaging member 26a and the base portion 26b1 of the back-side engaging member 26b are fixed by welding to the inner surfaces of the front portion 3 and the back portion 4, respectively. As shown in Figure 4B, the opening 22 is closed when the hook portion 26a2 of the front engaging member 26a and the hook portion 26b2 of the rear engaging member 26b are engaged, and the opening 22 is opened when the engagement is released, as shown in Figure 4C.

[0028] Furthermore, while the entire surfaces of the base portions 26a1 and 26b1 may be welded to the front portion 3 and the back portion 4, respectively, it is preferable that they be welded to the surfaces located above and below the hook portions 26a2 and 26b2, respectively. Moreover, it is even more preferable that the base portion of one of the front engaging member 26a and the back engaging member 26b (hereinafter referred to as "one engaging member") has a surface below the hook portion of that one engaging member that is not welded to the surface of the front portion 3 and the back portion 4 to which that one engaging member is fixed. For example, the base portion 26b1 of the back engaging member 26b may be welded to the inner surface of the back portion 4 on surfaces located above and below the hook portion 26b2, and the front engaging member 26a, which is welded to the front portion 3, may have its surface above the hook portion 26a2 welded to the inner surface of the front portion 3, while its surface below the hook portion 26a2 is not welded to the front portion 3. In other words, an unwelded portion with the front portion 3 may be provided, extending from the lower end of the base portion 26a1 to the upper end of the hook portion 26a2. In this case, when the internal pressure of the heated packaging bag 1 rises and it expands, it becomes more difficult for a force to be applied to the opening / closing member 26 in the direction of opening it, thereby suppressing leakage of contents and steam from the opening / closing member 26.

[0029] Furthermore, as shown in Figure 4B, the vertical distance d1 between the upper end of the hook portion 26a2 and the upper end of the hook portion 26b2 (in this embodiment, the upper end of the hook portion 26b2) and the periphery of the opening 22 (in other words, the easily tearable portion 25b of the upper opening portion 25) is preferably 5 mm or more, and can be, for example, 10 mm. Also, the vertical distance d2 between the upper end of the opening / closing member 26 (in other words, the upper ends of the base portions 26a1 and 26b1) and the lower end of the upper opening portion 25 (in this embodiment, the lower end of the tearing start portion 25a) is preferably 1 mm or more, and can be, for example, 2 mm. By setting the distances d1 and d2 as described above, a sufficiently large grip area can be secured for placing fingers on the upper end of the packaging bag 1 when opening the opening 22 with the opening / closing member 26.

[0030] The vertical length H1 of the cut-out section 5 can be, for example, 60 to 140 mm, and from the viewpoint of ease of removing the contents, it is preferable to be 120 mm or less, and more preferably 100 mm or less (93 mm in this embodiment). Specifically, H1 can be, for example, 60, 70, 80, 90, 93, 100, 110, 120, 130, 140 mm, and may be within the range of any two of the values ​​exemplified here. The vertical length H2 of the main body section 6 can be, for example, 40 to 200 mm, and is preferably 60 to 180 mm (77 mm in this embodiment). Specifically, H2 can be, for example, 40, 50, 60, 70, 77, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200 mm, and may be within the range of any two of the values ​​exemplified here. Furthermore, from the viewpoint of ensuring sufficient volume to accommodate the contents, it is preferable that the length H2 is longer than the length H3 from the center line E to the bottom end of the bottom film 20a. The value of H2-H3 is, for example, 20 to 80 mm (30 mm in this embodiment), and specifically, for example, 20, 30, 40, 50, 60, 70, 80 mm, and may be within the range of any two of the values ​​exemplified here.

[0031] As shown in Figure 2, the length L1 in the left-right direction at the bottom of the packaging bag 1 is preferably 150 to 250 mm, and more preferably 180 mm or more (200 mm in this embodiment), from the viewpoint of making it a size that can be placed on the turntable of a microwave oven. More specifically, for example, it is 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250 mm, and may be within the range of any two of the values ​​exemplified here. The left-right distance inside the packaging bag 1 (i.e., the inner width of the packaging bag 1) L2 is preferably 100 to 230 mm (180 mm in this embodiment), and more specifically, for example, it is 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230 mm, and may be within the range of any two of the values ​​exemplified here. Furthermore, the vertical distance H4 between the lower end of the hook portion 26a2 and the lower end of the hook portion 26b2 (in this embodiment, the lower end of the hook portion 26a2) and the upper end of the lower end welded portion 13 (i.e., the inner height of the packaging bag 1) is, for example, 100 to 160 mm (130 mm in this embodiment), specifically, for example, 100, 110, 120, 130, 140, 150, 160 mm, and may be within the range of any two of the values ​​exemplified here.

[0032] As shown in Figure 4A, in a cross-sectional view of the packaging bag 1 along the vertical direction, the vertical distance d3 between the base of the gusset portion 10 and the lower end of the lower end of the hook portion 26a2 and the lower end of the hook portion 26b2 (in this embodiment, the lower end of the hook portion 26a2) (i.e., the distance d3 from the lowest end of the hook portion to the base of the gusset portion) is, for example, 20 to 50 mm (35 mm in this embodiment), specifically, for example, 20, 25, 30, 35, 40, 45, 50 mm, and may be within the range of any two of the values ​​exemplified here.

[0033] As shown in Figure 4A, in a cross-sectional view of the packaging bag 1 along the vertical direction, the distance d4-d5, which is the distance d4 between the lower end of the easy-peel portion 27 and the base of the grommet portion 10 minus the length d5 ​​of the grommet portion 10, is, for example, 10 mm or less, and preferably 5 mm or less (4 mm in this embodiment). From the viewpoint of ease of bag making and ease of sealing after filling with contents, a larger value for d4-d5 is preferable, but if it is too large, the distance d3 will also increase, and the position of the base of the grommet portion 10 will move closer to the center of the inner height H4. In that case, when the packaging bag 1 expands, the grommet portion 10 will not stand up easily, pressure will not be applied to the steam vent seal portion 11 easily, and steam may not be able to escape from the steam vent seal portion 11 easily.

[0034] The ratio of the internal height H4 to the internal width L2 (H4 / L2) is, for example, 0.5 to 0.8 (approximately 0.72 in this embodiment), and specifically, for example, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, and may also be within the range of any two of the values ​​exemplified here. Furthermore, the ratio (d3 / H4) of the distance d3 from the lowest end of the hook portion to the base of the gusset portion to the inner height H4 is, for example, 0.2 to 0.4 (approximately 0.27 in this embodiment), and specifically, for example, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, and may be within the range between any two of the values ​​exemplified here. It is preferable that the values ​​of H4 / L2 and d3 / H4 are within the above ranges, from the viewpoint of how easily the gusset portion 10 stands up when the packaging bag 1 expands.

[0035] The films constituting the front portion 3 and the back portion 4 (i.e., the front film 43 and the back film 44) and the bottom film 20a may be composed of multiple layers. For example, a laminated film is constructed by laminating a first substrate layer, a second substrate layer, and a sealant layer in this order with an adhesive layer in between. A printing layer may be further provided between the first substrate layer and the second substrate layer.

[0036] For example, polyamide, polyolefin, polyethylene, polyester, etc., can be used as the base material. More specifically, stretched polyethylene terephthalate film, resin-deposited stretched polyethylene terephthalate film with a barrier resin vapor-deposited, silica-deposited stretched polyethylene terephthalate film, alumina-deposited stretched polyethylene terephthalate film, stretched nylon film, stretched polypropylene film, or polypropylene / ethylene-vinyl alcohol copolymer co-extruded co-stretched film can be used. The film constituting the base layer is preferably one that has linear cutability in the MD direction (the direction in which the film flows during manufacturing).

[0037] The adhesive layer is a layer for bonding the first substrate layer and the second substrate layer, and the second substrate layer and the sealant layer to each other in a laminated manner. The bonding method may be, for example, extruded lamination using polyethylene as the adhesive layer, or dry lamination using polyvinyl acetate adhesive, polyacrylic acid ester adhesive, cyanoacrylate adhesive, ethylene copolymer adhesive, cellulose adhesive, polyester adhesive, polyamide adhesive, amino resin adhesive, epoxy adhesive, polyurethane adhesive, etc. as the adhesive material.

[0038] The sealant layer is positioned so as to be exposed on the inner surface of the packaging bag 1. A welded portion is formed by welding (heat sealing) the sealant layers together. The sealant layer can be formed from a resin with excellent weldability. For example, the sealant layer can be made from polyolefin resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, or ethylene-propylene block copolymer. More specifically, unoriented polypropylene or linear low-density polyethylene can be used. The film constituting the sealant layer is preferably one that has linear cutability in the MD direction.

[0039] 1-2. Manufacturing method of packaging bag 1 The following outline of the manufacturing method for packaging bag 1 will be explained with reference to Figures 5A to 6B.

[0040] The packaging bag 1 is manufactured, for example, using a single peripheral film 40. In this film, the portions 24c and 25c corresponding to the easily tearable portions 24b of the lower opening 24 and 25b of the upper opening 25 are treated with an easily tearable finish. Next, as shown in Figure 5A, the inner surfaces of the ends of the single peripheral film 40 are overlapped to form an overlapping portion 10a. At this time, the peripheral film 40 is formed so that the portion 24c on the front portion 3 side and the portion 24c on the back portion 4 side overlap in the front-to-back direction of the packaging bag 1, and the portion 25c on the front portion 3 side and the portion 25c on the back portion 4 side overlap in the front-to-back direction of the packaging bag 1. Then, as shown in Figure 5B, the overlapping portion 10a is welded to form a gusset portion 10, and the remaining portion forms an elliptical ring C. This gives the front film 43 and back film 44 facing each other. The peripheral film 40 is a long film that extends continuously in the direction perpendicular to the plane of the paper (conveying direction) as shown in Figure 5A, and is supplied from a film roll. The front film 43 and the back film 44 are long films that extend continuously in the direction perpendicular to the plane of the paper (conveying direction) as shown in Figure 5B. Next, as shown in Figure 5B, the lower end C1 of the ring C is cut.

[0041] Alternatively, instead of processing the peripheral wall film 40 to obtain the front film 43 and back film 44, the front film 43 and back film 44 may be supplied from separate film rolls. In this case, portions 24c and 25c corresponding to the easily tearable portions 24b and 25b on the front portion 3 side and back portion 4 side are formed on the front film 43 and back film 44, respectively, and the front film 43 and back film 44 are overlapped so that the portions 24c and 25c on the front portion 3 side and back portion 4 side overlap in the front-to-back direction of the packaging bag 1.

[0042] Next, as shown in Figure 6A, the bottom film 42 is inserted between the front film 43 and the back film 44 from the lower end C1 side. The bottom film 42 is a long film that extends continuously in the direction perpendicular to the plane of the paper (conveying direction) as shown in Figure 5B. Then, the front film 43 and the back film 44 are separated at the upper end C2, and the upper end is opened. Subsequently, as shown in Figure 6B, the opening / closing member 26 is inserted between the front film 43 and the back film 44 from the opened upper end. Then, the bases 26a1 and 26b1 of the opening / closing member 26 are welded to the front film 43 and the back film 44, respectively, and the bottom film 42 is also welded to the front film 43 and the back film 44 (not shown). Then, a horizontal seal portion (not shown) is formed that extends in a direction perpendicular to the conveying direction so that the front film 43 and the back film 44 are welded to each other at the same pitch as the length L1 in Figure 2. When forming the lateral seal portion, a portion of the opening / closing member 26 that is located within the lateral seal portion is crushed and becomes part of the lateral seal portion. Next, the front film 43, the back film 44, and the bottom film 42 are separated along the lateral seal portion. In this embodiment, the welding of the opening / closing member 26 and the welding of the bottom film 42 are performed at the same time, but one of the welding of the opening / closing member 26 or the welding of the bottom film 42 may be performed before the other. For example, the welding of the bottom film 42 may be performed before the welding of the opening / closing member 26. Furthermore, in this embodiment, the step of inserting the bottom film 42 between the front film 43 and the back film 44 from the lower end C1 side is performed before the step of inserting the opening / closing member 26 between the front film 43 and the back film 44 from the upper end C2 side, but these steps may be performed together at the same time, or the latter step may be performed before the former step.

[0043] Here, as shown in Figures 7A and 8A, before forming the upper end welded portion 16 and the heat-sealed portion 28 of the easy-peel portion 27 (i.e., before heat sealing is applied to the upper ends of the front film 43 and back film 44 and the heat-sealed portion 28 of the easy-peel portion 27), the hook portions 26a2 and 26b2 of the opening / closing member 26 are disengaged, the filling nozzle 30 is inserted, and the cooking liquid (contents) Q is filled. Here, in this filling process, it is preferable that the tip of the filling nozzle 30 that discharges the contents Q is positioned below the opening / closing member 26 in the vertical direction of the packaging bag 1, as shown in Figure 8A. This makes it possible to suppress the contents Q from adhering to the opening / closing member 26. Furthermore, it is preferable that the contents Q is filled into the packaging bag 1 with the tip of the filling nozzle 30 positioned below the lower end of the area where the heat-sealed portion 28 is to be formed in the vertical direction of the packaging bag 1. This prevents the contents Q from adhering to the heat-seal portion 28, which would hinder the bonding of the easy-peel portion 27 to the heat-seal portion 28.

[0044] Next, after the filling process, as shown in Figures 7B and 8B, it is preferable that a sealing process is performed in which the hook portions 26a2 and 26b2 of the opening / closing member 26 are engaged to seal the opening / closing member 26, and at the same time, an easy-peel portion joining process is performed in which the easy-peel portion 27 is joined (for example, welded) to the heat-seal portion 28. It is preferable that the upper end joining process for forming the upper end welded portion 16 is performed simultaneously with or after the easy-peel portion joining process. After the sealing process, the easy-peel portion joining process, and the upper end joining process, the packaging bag 1 is heated and retort sterilized. As a result, the packaging bag 1 shown in Figure 1 is obtained.

[0045] As described above, the timing of (1) the formation of the heat-seal portion 28 (i.e., the easy-peel portion joining process), (2) the engagement of the hook portions 26a2 and 26b2 (i.e., the sealing process), and (3) the formation of the upper end welded portion 16 (i.e., the upper end joining process) can also be performed in the order of (1) → (2) → (3). This suppresses the retention of excess air inside the packaging bag 1 and facilitates the formation of the heat-seal portion 28 and / or the engagement of the hook portions 26a2 and 26b2. In this embodiment, (1) and (2) are performed simultaneously before (3) is performed (i.e., (1) and (2) → (3)), which makes it possible to combine the device for forming the heat-seal portion 28 and the device for engaging the hook portions 26a2 and 26b2 into one, thereby improving manufacturing efficiency. Furthermore, since the heat-sealed portion 28 has a weaker welding strength compared to the upper end welded portion 16, welding does not take much time and can be done simultaneously with the engagement of the hook portions 26a2 and 26b2.

[0046] 1-3. Heating method for packaging bag 1 A method for heating and pressurizing food using packaging bag 1 will be described. First, the packaging bag 1 is torn in the left-right direction along the upper opening portion 25. Then, the opening / closing member 26 is opened. By opening the opening / closing member 26, the easy-peel portion 27, which is formed continuously with the opening / closing member 26, is pulled, and the easy-peel portion 27 peels off from the film (in this embodiment, the back film 44 (back portion 4)) to which it is joined at the heat-seal portion 28. At this time, the heat-seal portion 28 is a seal with weaker welding strength compared to the side-end welding portion 12, the lower end welding portion 13, and the upper end welding portion 16, so it can be easily peeled off. In addition, because it is easy to peel off, the easy-peel portion 27 can be peeled off without damaging the film (in this embodiment, the back film 44 (back portion 4)) to which the easy-peel portion 27 is joined at the heat-seal portion 28.

[0047] Next, the necessary vegetables and other ingredients may be added to the contents Q inside the packaging bag 1. Then, the opening and closing member 26 is engaged to close the opening of the packaging bag 1, and the packaging bag 1 is placed in a microwave oven and heated for a certain period of time. At the start of heating, the packaging bag 1 containing the contents Q (and ingredients) is sealed (that is, the opening and closing member 26 is closed along its entire length, and no steam passage is formed in the steam vent seal portion 11. It is obvious that no steam passages are formed in the other joints of the packaging bag 1 (side end weld portion 12, bottom end weld portion 13, top end weld portion 16)). The packaging bag 1 may be placed in the microwave oven in either an upright or lying position.

[0048] Since the opening / closing member 26 is closed, the contents Q (and ingredients) are heated and the inside of the packaging bag 1 becomes high pressure. However, the high-temperature air (steam) inside the packaging bag 1 is released from the steam vent seal 11 provided in the grommet portion 10, allowing the inside of the packaging bag 1 to be maintained at a constant pressure (steam venting). Because the steam vent seal 11 is provided, the packaging bag 1, when the contents Q (and ingredients) are heated, becomes high pressure inside and swells up, preventing it from bursting from the opening / closing member 26 and scattering the contents, while still allowing for heating and pressurized cooking. After cooking is finished, the contents Q (and ingredients) can be transferred from the packaging bag 1 to a plate or other container, or the packaging bag 1 can be used as tableware as is. Furthermore, because the opening / closing member 26 is provided, it is convenient that the packaging bag can be resealed with some of the contents Q (and ingredients) remaining inside. Furthermore, if the amount of contents Q (and ingredients) remaining decreases, the packaging bag 1 can be torn from side to side along the lower opening 24 to make it easier to remove the contents Q (and ingredients), or the packaging bag 1 can be used as tableware.

[0049] 3. Other Embodiments While embodiments have been described above, the technical concept in this disclosure can also be adopted in the following embodiments.

[0050] The packaging bag 1 does not necessarily have to have a bottom portion 2 made of a bottom film 20a. In that case, the front portion 3 and the back portion 4 can be welded together on the underside of the packaging bag 1 to form the bottom of the packaging bag 1. The steam vent seal portion 11 may be provided in a part other than the gable portion 10. The method for manufacturing the packaging bag 1 is not limited to the method described in the embodiments above.

[0051] Although various embodiments of the present invention have been described above, these are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0052] 1: Packaging bag 2: Bottom part 3: Front part 4: Back part 5: Cut-off section 6: Main body 7:Aperture 10: Gassho part 10a: Joint part 11: Steam vent seal section 12: Side end welding part 13: Lower end welding part 13a: Sloping section 14: Air pocket 15:Fixed part 16: Upper end welding part 20a: Bottom film 21: Peripheral part 22: Opening 24: Lower opening part 24a:Tear start part 24b: Easy tearing part 24c: part 25: Upper opening part 25a:Tear start part 25b: Easy tearing part 25c: part 26: Opening / closing member 26a: Front side engagement member 26a1: Base 26a2: Hook part 26b: Rear side engagement member 26b1: Base 26b2: Hook part 27: Easy Peel Section 28: Heat seal section 30: Filling nozzle 40: Peripheral wall film 42: Bottom film 43: Front film 44: Back film C: ring C1: Bottom end C2:Top edge E: Chuo Line F :Area H1: Length H2: Length H3: Length H4: Internal height J:Position L1: Length L2:Inner width Q:Contents R: Notch d1: distance d2: distance d3: distance d4: distance d5: Length

Claims

1. A microwave packaging bag made of a flexible film formed into a bag shape, The aforementioned packaging bag is A circumferential surface having a front portion and a back portion that face each other, An opening / closing member that reseals the contents by engaging a front-side engaging member and a rear-side engaging member, Equipped with, The front engagement member and the rear engagement member are fixed to the inside of the front and rear portions, respectively. The easy-peel section is provided below the opening / closing member to seal the contents and prevent the contents from adhering to the opening / closing member. The front portion is provided with a girdle portion formed by overlapping the inner surfaces of both side edges of the film. A packaging bag, wherein the gusset portion is provided with a steam vent seal portion through which steam generated inside the packaging bag during heating is released.

2. A packaging bag according to claim 1, A packaging bag in which the easy-peel portion is formed continuously with the front engagement member or the rear engagement member, and is joined at a heat-seal portion provided on the inside of the front portion and the rear portion that does not have the easy-peel portion continuously attached.

3. A packaging bag according to claim 1, A packaging bag in which, in a cross-sectional view along the vertical direction of the packaging bag, the distance d4-d5, which is the distance d4 between the lower end of the easy-peel portion and the base of the gusset portion and the length d5 ​​of the gusset portion, is 5 mm or less.

4. A packaging bag according to claim 1, The circumferential portion is provided with an opening portion for opening the packaging bag by tearing the circumferential portion. The opening / closing member is configured to open and close the opening formed when the packaging bag is opened at the opening portion of the packaging bag.

5. A method for manufacturing microwave packaging bags, The aforementioned packaging bag is A circumferential surface having a front portion and a back portion that face each other, An opening / closing member that reseals the contents by engaging a front-side engaging member and a rear-side engaging member, Equipped with, The front engagement member and the rear engagement member are fixed to the inside of the front and rear portions, respectively. The easy-peel section is provided below the opening / closing member to seal the contents and prevent the contents from adhering to the opening / closing member. The aforementioned method, The process includes a sealing step of sealing the opening / closing member after filling the contents into the packaging bag, and an easy-peel portion joining step of joining the easy-peel portion to a heat-seal portion provided on the inside of the circumferential portion. A method wherein the sealing step and the easy-peel portion joining step are performed simultaneously.

6. A method for manufacturing microwave packaging bags, The aforementioned packaging bag is A circumferential surface having a front portion and a back portion that face each other, An opening / closing member that reseals the contents by engaging a front-side engaging member and a rear-side engaging member, Equipped with, The front engagement member and the rear engagement member are fixed to the inside of the front and rear portions, respectively. The easy-peel section is provided below the opening / closing member to seal the contents and prevent the contents from adhering to the opening / closing member. The aforementioned method, The process comprises a filling step of filling the contents into the packaging bag, a sealing step of sealing the opening and closing member after the filling step, an easy-peel portion joining step of joining the easy-peel portion at a heat-seal portion provided on the inside of the circumferential portion, and an upper end joining step of joining the front portion and the back portion at the upper end of the packaging bag. In the filling step, the tip of the filling nozzle that dispenses the contents is positioned below the opening / closing member.

7. A method for heating a packaging bag in a microwave oven according to any one of claims 1 to 4, A method wherein the packaging bag containing the contents is sealed at the start of microwave heating of the packaging bag.

Images