Packaging bags, sealing strips, and manufacturing methods of packaging bags

Abstract

A packaging bag is provided that can suppress the formation of openings in areas other than the vapor release seal. According to the present invention, a packaging bag is provided that is formed by heat-sealing a film at a sealing portion, wherein the sealing portion has a vapor release seal that forms a vapor flow path as internal pressure increases, the vapor release seal having a curved shape bending toward the inside of the packaging bag, the vapor release seal including a first region and a second region, the first region including the front end of the curved shape, the second region being adjacent to the first region, and the sealing strength of the first region being higher than the sealing strength of the second region.

Description

Technical Field

[0001] This invention relates to a packaging bag suitable for microwave heating of contents. Background Technology

[0002] Patent Document 1 discloses a packaging bag constructed by heat-sealing a flexible membrane at a sealing portion. To allow steam generated during microwave heating of the contents to escape, the packaging bag is provided with a steam release sealing portion.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: WO2013 / 100058 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In Patent Document 1, the vapor release seal has a curved shape that bends towards the inside of the packaging bag. As the internal pressure of the packaging bag increases, the front end of the curved shape peels off, thereby forming an opening through which vapor is released. Ideally, for vapor to be released quickly from the packaging bag, the peeling, which begins at the front end of the curved shape, should proceed rapidly beyond the front end, causing the opening to widen. However, there are cases where the peeling is not rapid. If the peeling is not rapid, for example, in the case of rapid heating, the internal pressure of the packaging bag may become too high, potentially causing an opening to form in areas other than the vapor release seal, allowing vapor to escape.

[0008] The present invention was made in view of this situation, and provides a packaging bag that can suppress the formation of openings in areas other than the vapor release seal.

[0009] means for solving problems

[0010] According to the present invention, a packaging bag is provided, which is formed by heat-sealing a film at a sealing portion, the sealing portion having a vapor release sealing portion that forms a vapor flow path as the internal pressure rises, the vapor release sealing portion having a curved shape that bends toward the inside of the packaging bag, the vapor release sealing portion including a first region and a second region, the first region including the front end of the curved shape, the second region being adjacent to the first region, and the sealing strength of the first region being higher than the sealing strength of the second region.

[0011] In the packaging bag of the present invention, the sealing strength of the first region, including the curved front end constituting the vapor release seal, is higher than the sealing strength of the second region adjacent to the first region. Therefore, if peeling begins in the first region, peeling will proceed rapidly in the second region. Consequently, the opening formed in the vapor release seal rapidly expands, thus preventing the formation of openings in locations other than the vapor release seal.

[0012] The following examples illustrate various embodiments of the present invention. These embodiments can be combined with each other.

[0013] Preferably, in the described packaging bag, the packaging bag has a front portion, the front portion having a lower front portion and a upper front portion, and in the clamming portion formed by the partial overlap of the lower front portion and the upper front portion, the lower front portion and the upper front portion are heat-sealed at a pair of side sealing portions, a pair of end sealing portions and the vapor release sealing portion, the side sealing portions being disposed along the side edges of the clamming portion and connected to the vapor release sealing portion via the end sealing portion, the sealing strength of the end sealing portion being higher than the sealing strength of the first region.

[0014] Preferably, in the described packaging bag, the vapor release seal has an inner region and an outer region, which are formed by dividing the vapor release seal by a boundary line disposed between the inner edge and the outer edge of the vapor release seal, and the sealing strength of the inner region and the outer region are different from each other.

[0015] Preferably, a sealing strip for manufacturing the described packaging bag has a vapor release seal forming portion for forming the vapor release seal portion, the vapor release seal forming portion having a first region forming portion for forming a first region and a second region forming portion for forming a second region, the protrusion of the first region forming portion being greater than the protrusion of the second region forming portion.

[0016] Preferably, the sealing strip described herein has an end seal forming portion for forming the end seal portion, the protrusion of the end seal forming portion being greater than the protrusion of the first region forming portion.

[0017] Preferably, the sealing strip described herein has a first sealing unit and a second sealing unit. When the vapor release sealing forming portion is used as the first vapor release sealing forming portion, the first sealing unit has the first vapor release sealing forming portion, and the second sealing unit has the second vapor release sealing forming portion for forming the vapor release sealing portion. The line widths of the first vapor release sealing forming portion and the second vapor release sealing forming portion are different from each other.

[0018] Preferably, a method for manufacturing the described packaging bag includes a step of forming the vapor release seal portion by a sealing step including a first sealing step and a second sealing step. In the first sealing step, the film is heat-sealed using a first sealing unit having a first vapor release seal forming portion, and in the second sealing step, the film is heat-sealed using a second sealing unit having a second vapor release seal forming portion. The line widths of the first vapor release seal forming portion and the second vapor release seal forming portion are different from each other. Attached Figure Description

[0019] Figure 1 This is a perspective view of the packaging bag 1 according to the first embodiment of the present invention.

[0020] Figure 2A This is a top view of the packaging bag 1 according to the first embodiment of the present invention. Figure 2B yes Figure 2A A magnified view of region B in the image.

[0021] Figure 3 yes Figure 2A AA section view in the image.

[0022] Figure 4 This is a side view showing the state in which the film 9 is folded while the packaging bag 1 can be manufactured by heat sealing.

[0023] Figure 5A This is a perspective view of the sealing strip 20 according to the first embodiment of the present invention. Figures 5B-5C They are Figure 5A Enlarged views of regions B and C in the image.

[0024] Figure 6A This is a top view of the packaging bag 1 according to the second embodiment of the present invention. Figure 6B yes Figure 6A A magnified view of region B in the image.

[0025] Figure 7A This is a perspective view of the sealing strip 20 according to the second embodiment of the present invention. Figures 7B-7C They are Figure 7A Enlarged views of regions B and C in the image. Detailed Implementation

[0026] The following describes embodiments of the present invention. The various features shown in the embodiments described below can be combined with each other. Alternatively, each feature can independently constitute an invention.

[0027] 1. First Implementation Method

[0028] 1-1. Structure of Packaging Bag 1

[0029] like Figures 1-3As shown, the packaging bag 1 of the first embodiment of the present invention is constructed by heat-sealing the sealing portion 4 with a film 9. The packaging bag 1 has a front portion 2 and a back portion 3. The sealing portion 4 has a top sealing portion 4t formed along the upper edge 1t of the packaging bag 1 and a pair of side sealing portions 4s formed along the right side edge 1r or the left side edge 1l. Moreover, in the sealing portion 4, there is a pair of side sealing portions 6, a pair of end sealing portions 7, and a vapor release sealing portion 8 in the clamshell portion 5. The lower edge 1b of the packaging bag 1 is not heat-sealed before the contents are contained, but is heat-sealed after the contents are contained in the packaging bag 1 to form a bottom sealing portion. Thus, the sealing portion 4 is provided around the entire circumference of the packaging bag 1, and the interior of the packaging bag 1 is sealed.

[0030] like Figure 3 As shown, the film 9 is preferably a laminated film having a substrate layer 9a and a sealant layer 9b, and more preferably has an adhesive layer and a printing layer between the substrate layer 9a and the sealant layer 9b.

[0031] The substrate layer 9a is configured to be exposed on the outer surface of the packaging bag 1, and the sealant layer 9b is configured to be exposed on the inner surface of the packaging bag 1. The sealant layers 9b are heat-sealed together to form a sealed portion 4.

[0032] The substrate layer 9a is formed of a material with excellent strength and high impact resistance. Polyamide, polyolefin, polyethylene, polyester, etc., can be used as the substrate layer 9a. More specifically, stretched polyethylene terephthalate film, 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, etc., can be used. The film constituting the substrate layer 9a is preferably a film with linear shear properties in the MD direction (the flow direction of the film during manufacturing). Antibacterial and antiviral agents (such as silver ions) can be mixed into the outermost substrate layer 9a. In particular, by incorporating exudative antibacterial and antiviral agents into the substrate layer 9a, the antibacterial and antiviral treatment of the surface of the substrate layer 9a is promoted when heated to a high temperature in a microwave oven, resulting in good hygiene when removed from the microwave oven.

[0033] The adhesive layer is used to bond the substrate layer 9a and the sealant layer 9b in a stacked manner. As an adhesive method, for example, it can be extrusion lamination using polyethylene or the like as the adhesive layer, or dry lamination using adhesives such as polyvinyl acetate adhesives, polyacrylate adhesives, cyanoacrylate adhesives, ethylene copolymer adhesives, cellulose adhesives, polyester adhesives, polyamide adhesives, amino resin adhesives, epoxy adhesives, and polyurethane adhesives as adhesive materials.

[0034] The sealant layer 9b can be formed from a resin with excellent heat-sealing properties. As the sealant layer 9b, it can be formed from polyolefin resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, and ethylene-propylene block copolymer. More specifically, unstretched polypropylene or linear low-density polyethylene can be used.

[0035] like Figures 1-3 As shown, the front portion 2 has a lower front portion 2d and an upper front portion 2u. The lower front portion 2d and the upper front portion 2u are heat-sealed to the back portion 3, respectively. In the clammed portion 5 formed by the partial overlap of the lower front portion 2d and the upper front portion 2u, the lower front portion 2d and the upper front portion 2u are heat-sealed at a pair of side sealing portions 6, a pair of end sealing portions 7, and a vapor release sealing portion 8. In the clammed portion 5, the side sealing portions 6 are provided along the right side edge 1r and the left side edge 1l. The end sealing portions 7 are configured to connect the side sealing portions 6 and the vapor release sealing portions 8. The end sealing portions 7 preferably extend to the right side edge 1r or the left side edge 1l and overlap with the side sealing portions 6. The width of the end sealing portions 7 narrows from the side sealing portions 6 toward the vapor release sealing portions 8. The upper edge 5t of the clammed portion 5 is parallel to the upper edge 1t of the packaging bag 1, and the outer edge 7b of the end sealing portions 7 is parallel to the upper edge 5t. The inner edge 7a of the end seal 7 faces the vapor release seal 8 and is close to the outer edge 7b. An unsealed portion 10, where the membranes are not heat-sealed, is provided between the outer edge 7b and the upper edge 5t of the end seal 7. Alternatively, the unsealed portion 10 may be omitted, and the outer edge 7b may be aligned with the upper edge 5t.

[0036] The vapor release seal 8 is configured to form a vapor flow path as the internal pressure of the packaging bag 1 increases. The vapor release seal 8 has a curved shape formed by bending towards the inside of the packaging bag 1. The inner edge 8a of the vapor release seal 8 is preferably generally V-shaped, and the outer edge 8b of the vapor release seal 8 is also preferably generally V-shaped. The inner edge 8a and the outer edge 8b are preferably parallel, and preferably entirely parallel. The distance between the inner edge 8a and the outer edge 8b (i.e., the line width of the vapor release seal 8) is, for example, 1 to 5 mm, preferably 2 to 4 mm. Specifically, this distance is, for example, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0 mm, or may be within any two of the values ​​exemplified herein.

[0037] The vapor release seal 8 has a first region 8d including a curved front end 8c and a second region 8e adjacent to the first region. The second region 8e is the region of the vapor release seal 8 other than the first region 8d. The inner edge 8a and the outer edge 8b may be parallel to the first region 8d or parallel to the second region 8e. An unsealed portion 10 is preferably provided between the outer edge 8b and the upper edge 5t. A cutout 12 is preferably provided between the outer edge 8b and the upper edge 5t.

[0038] The sealing strength of the first region 8d is higher than that of the second region 8e. The vapor release seal 8 is designed to peel off starting from the front end 8c; however, if peeling from the front end 8c is too easy, peeling at the front end 8c may begin unexpectedly, such as when an impact is applied to the packaging bag 1. On the other hand, if the overall sealing strength of the vapor release seal 8 is increased to prevent accidental opening, peeling may not proceed quickly even if it begins at the front end 8c the next time. Therefore, in this embodiment, the sealing strength of the first region 8d is higher than that of the second region 8e. In this structure, because the sealing strength of the first region 8d is higher, peeling at the front end 8c is suppressed from starting unexpectedly. On the other hand, because the sealing strength of the second region 8e is lower, if peeling begins in the first region 8d, peeling will proceed rapidly in the second region 8e. Therefore, because the opening formed in the vapor release seal 8 expands rapidly, the formation of openings outside the vapor release seal is suppressed. Furthermore, in this specification, unless otherwise specified, sealing strength refers to sealing strength per unit area.

[0039] When the overall width (length in the left-right direction) of the vapor release sealing part 8 is set as W, and the width of the first region 8d is set as W1, W1 / W is preferably 0.05 to 0.5, more preferably 0.1 to 0.3. Specifically, W1 / W can be, for example, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50, or it can be within any two of the values ​​shown in this example.

[0040] The vapor release seal 8 preferably has an inner region 8g and an outer region 8h, which are formed by dividing the vapor release seal 8 by a boundary line 8f disposed between the inner edge 8a and the outer edge 8b of the vapor release seal 8. Preferably, the sealing strengths of the inner region 8g and the outer region 8h are different, and preferably the sealing strength of the inner region 8g is higher than that of the outer region 8h. By increasing the sealing strength of a portion of the linewidth direction of the vapor release seal 8, it is possible to suppress the vapor release seal 8 from peeling off unexpectedly. The boundary line 8f is preferably parallel to at least one of the inner edge 8a and the outer edge 8b. The ratio of the linewidth of the inner region 8g to the overall linewidth of the vapor release seal 8 is, for example, 0.1 to 0.9, preferably 0.2 to 0.8. Specifically, the ratio can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9, or it can be within any two of the values ​​shown in this example. In this embodiment, the line width ratio of the inner region 8g is 0.5.

[0041] 1-2. How to use packaging bag 1

[0042] After the contents are filled into the packaging bag 1, a bottom sealing portion is formed at the lower edge of the packaging bag 1. Thus, the packaging bag 1 is sealed.

[0043] If the packaging bag 1 filled with contents is heated in a microwave oven, the internal pressure of the packaging bag 1 increases due to the steam generated by the moisture contained in the contents. As a result, if peeling begins in the first region 8d, including the curved front end 8c of the steam release seal 8, the peeling proceeds rapidly in the second region 8e. Consequently, the steam flow path formed in the steam release seal 8 rapidly expands, and the steam is quickly discharged to the outside. The steam is discharged to the outside from the upper edge 5t of the clasped portion 5 and the cut 12, respectively.

[0044] 1-3. Manufacturing method of packaging bag 1

[0045] The packaging bag 1 can be formed by forming a sealing portion 4 in the film 9. In one example, by folding it as shown... Figure 4 The film 9, as shown in the figure, can be heat-sealed to form a sealing part 4. Figure 4 The membrane 9 in its current state has a front portion 2 and a back portion 3, with the upper and lower edges of the front portion 2 and the back portion 3 connected to each other. The front portion 2 and the back portion 3 may also be separated at one or both of their upper and lower edges. The front portion 2 has a lower front portion 2d and a higher front portion 2u, with the lower front portion 2d and the upper front portion 2u partially overlapping to form a clasped portion 5. In one example, after forming a pair of end seals 7 and a vapor release seal 8 in the clasped portion 5, by forming a top seal 4t, a side seal 4s, and a side seal 6, a... Figure 1 The packaging bag 1 with the structure shown.

[0046] Able to use Figures 5A-5C The sealing strip 20 shown forms an end sealing portion 7 and a vapor release sealing portion 8.

[0047] The sealing strip 20 has a first sealing unit 21 and a second sealing unit 22. The first sealing unit 21 has a vapor release sealing forming portion 21a for forming a vapor release sealing portion 8 and an end sealing forming portion 21b for forming an end sealing portion 7. The vapor release sealing forming portion 21a has a first region forming portion 21a1 for forming a first region 8d and a second region forming portion 21a2 for forming a second region 8e. The protrusion of the first region forming portion 21a1 is greater than that of the second region forming portion 21a2. The protrusion of the end sealing forming portion 21b is greater than that of the first region forming portion 21a1. That is, the protrusion is second region forming portion 21a2 < first region forming portion 21a1 < end sealing forming portion 21b. During heat sealing, the portion with a larger protrusion is pressed more forcefully onto the membrane 9, and the sealing strength of the membrane 9 is higher. Therefore, when the sealing strip 20 with the above structure is used to form the end sealing part 7 and the vapor release sealing part 8, the sealing strength can be set to the second region 8e < the first region 8d < the end sealing part 7.

[0048] The difference in the amount of protrusion between the second region forming portion 21a2 and the first region forming portion 21a1 is, for example, 1 to 100 μm, preferably 5 to 30 μm. Specifically, it is, for example, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 μm, or it can be within any two of the values ​​shown in this example. The difference in the amount of protrusion between the first region forming portion 21a1 and the end sealing forming portion 21b is similar.

[0049] The basic structure of the second sealing unit 22 is the same as that of the first sealing unit 21. The reference numerals for various parts of the second sealing unit 22 are the reference numerals after changing "21" to "22" for the corresponding parts of the first sealing unit 21. The first sealing unit 21 and the second sealing unit 22 are connected to each other at the end sealing forming portions 21b and 22b.

[0050] Regarding the vapor release sealing forming portions 21a and 22a of the first sealing unit 21 and the second sealing unit 22, the distance between the inner and outer edges of the vapor release sealing forming portions 21a and 22a (i.e., the line width of the vapor release sealing forming portion) is different from each other. The value of (line width of the larger portion) / (line width of the smaller portion) is, for example, 1.1 to 5, preferably 1.5 to 3. Specifically, this value is, for example, 1.1, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, or it can be within any two of the values ​​exemplified here. In this embodiment, the above value is 2. In this embodiment, in Figures 5A-5C In this case, the line width of the vapor release seal forming portion 21a is smaller than the line width of the vapor release seal forming portion 22a, or the line width of the vapor release seal forming portion 22a is smaller than the line width of the vapor release seal forming portion 21a.

[0051] The vapor release seal 8 can be formed by a sealing process including a first sealing process and a second sealing process. In the first sealing process, the membrane 9 is heat-sealed using a first sealing unit 21 having a first vapor release seal forming part 21a, and in the second sealing process, the membrane 9 is heat-sealed using a second sealing unit 22 having a second vapor release seal forming part 22a.

[0052] In one example, after the first sealing step, the membrane 9 can be moved to move the end sealing portion 7 and the vapor release sealing portion 8 formed in the first sealing step to a position facing the second sealing unit 22, and then the second sealing step is performed. Regarding the sealing strip 20, since the first sealing unit 21 and the second sealing unit 22 are adjacent, the first sealing step can be performed on the upstream second packaging bag 1 while the second sealing step is performed on the first packaging bag 1. Therefore, when multiple packaging bags 1 are manufactured sequentially, the manufacturing time for each packaging bag can be shortened.

[0053] The line widths of the vapor release sealing portions 21a and 22a are different, and the sealing width of the membrane 9 is also different. Through this process, by forming the vapor release sealing portion 8, the sealing strengths of the inner region 8g and the outer region 8h can be made different. In one example, only the inner region 8g is heat-sealed in the first sealing process, and both the inner region 8g and the outer region 8h are heat-sealed in the second sealing process. As a result, the sealing strength of the inner region 8g can be made higher than that of the outer region 8h.

[0054] Furthermore, this example illustrates a case where a sealing strip 20 has a first sealing unit 21 and a second sealing unit 22, but the first sealing unit 21 and the second sealing unit 22 can also be disposed on different sealing strips.

[0055] 2. Second Implementation Method

[0056] use Figures 6A to 7C The second embodiment of the present invention will be described below. This embodiment is similar to the first embodiment, and the following description focuses on the differences.

[0057] 2-1. Structure of Packaging Bag 1

[0058] In the packaging bag 1 of the first embodiment, depending on the resin composition of the sealant layer, the sealing strength at the first region 8d becomes too high, and the vapor release becomes slow. As a result, sometimes a loud noise is made when the vapor release seal 8 is opened. For example, when the sealant layer is made of LLDPE (Linear low-density polyethylene), the phenomenon of excessively high sealing strength at the first region 8d is more likely to occur compared to the case where the sealant layer is made of unstretched polypropylene.

[0059] To reduce the sealing strength at the first region 8d, the pressure of pressing the sealing strip 20 can be reduced. However, fine-tuning the pressure of pressing the sealing strip 20 is not easy. Therefore, if the pressure of pressing the sealing strip 20 is reduced, the deviation of the sealing strength of each product is likely to increase.

[0060] In this embodiment, to solve this problem, a protrusion 8d2 is provided in the first region 8d, thereby improving the peelability of the first region 8d. As a result, regardless of the resin composition of the sealant layer, loud noises can be suppressed when the vapor release seal 8 is opened.

[0061] Specifically, in this embodiment, such as Figure 6A , Figure 6B As shown, the first region 8d has a base portion 8d1 and a protrusion 8d2. The protrusion 8d2 protrudes from the base portion 8d1 toward the inside of the packaging bag 1. A stepped portion 8i is provided on the inner edge 8a of the base portion 8d1. In the stepped portion 8i, a direction perpendicular to the lower edge (root) 5b of the clasped portion 5 (…) Figure 6B The angle (hereinafter referred to as the "tilt angle") of the protrusion 8d2 in the vertical direction is larger than that of the second region e and the protrusion 8d2. In this embodiment, the tilt angle is 90 degrees. By providing the stepped portion 8i, a step is formed between the second region e and the protrusion 8d2. As a result, the width of the protrusion 8d2 at the lower end 8j of the protrusion 8d2 becomes smaller, and the protrusion 8d2 is inverted triangular in shape. The tilt angle of the inner edge 8a of the protrusion 8d2 with the largest tilt angle is the same as or smaller than the tilt angle of the inner edge 8a of the second region 8e with the largest tilt angle. As a result, the protrusion 8d2 protrudes steeply, and pressure becomes more easily concentrated at the front end of the protrusion 8d2.

[0062] A weak sealing region 8d3 is provided at the front end of the protrusion 8d2. The weak sealing region 8d3 is a part where the sealing strength is weaker than that of the protrusion 8d2. By providing the weak sealing region 8d3, peeling at the protrusion 8d2 becomes easier to initiate.

[0063] Alternatively, in this embodiment, the linewidth of the inner region 8g is approximately 0.8 times the overall linewidth of the vapor release seal 8. This further suppresses the possibility of accidental peeling of the second region 8e.

[0064] 2-2. Manufacturing method of packaging bag 1

[0065] In this embodiment, using Figures 7A to 7C The sealing strip 20 shown forms an end sealing portion 7 and a vapor release sealing portion 8.

[0066] In the first sealing unit 21 of the sealing strip 20 of this embodiment, the first region forming portion 21a1 for forming the first region 8d has a base portion 21a3 and a protrusion 21a4. A chamfered portion 21a5 is provided at the front end of the protrusion 21a4. The chamfered portion 21a5 is formed by chamfering the front end of the protrusion 21a4. This chamfer can be an R-angle (rounded corner) or a C-angle (45-degree chamfer). By providing the chamfered portion 21a5, damage to the membrane caused by the protrusion 21a4 is suppressed. The base portion 21a3, the protrusion 21a4, and the chamfered portion 21a5 form the base portion 8d1, the protrusion 8d2, and the weak sealing region 8d3 of the first region 8d, respectively. The second sealing unit 22 has the same structure, and the reference numerals for various parts of the second sealing unit 22 are changed from "21" to "22" in the reference numerals for the parts corresponding to the first sealing unit 21.

[0067] Alternatively, in this embodiment, the distance between the inner and outer edges of the vapor release sealing portions 21a and 22a (i.e., the line width of the vapor release sealing portion) is different from each other. The value of (line width of the larger portion) / (line width of the smaller portion) is 1.25.

[0068] Alternatively, in this embodiment, the end sealing forming portion 21b and the first region forming portion 21a1 protrude by the same amount, and their protrusion amount is greater than that of the second region forming portion 21a2. Therefore, when the end sealing portion 7 and the vapor release sealing portion 8 are formed using the sealing strip 20 of this embodiment, the sealing strength is: second region 8e < first region 8d = end sealing portion 7.

[0069] Example

[0070] <Example 1>

[0071] A packaging bag 1 with a vapor release seal 8 having the shape of the first embodiment is made by laminating a membrane 9, which is formed by stacking a 15 μm thick polyamide layer and a 60 μm thick unstretched polypropylene layer. The packaging bag 1 is filled with water.

[0072] The packaging bag 1 was heated in a microwave oven to test whether the steam release seal 8 functioned properly (steam release test). It was confirmed that no loud noise was made and steam was released from the steam release seal 8.

[0073] <Example 2>

[0074] Except for changing the unstretched polypropylene layer to an LLDPE layer, the packaging bag 1 was manufactured in the same manner as in Example 1, and a vapor release test was conducted. Sometimes a loud sound was heard when the vapor release seal 8 was opened.

[0075] <Example 3>

[0076] Except for changing the shape of the steam release seal 8 to the second embodiment, the packaging bag 1 was manufactured in the same manner as in Embodiment 2, and a steam discharge test was conducted to confirm that no loud noise was emitted and steam was discharged from the steam release seal 8.

[0077] Explanation of reference numerals in the attached figures

[0078] 1: Packaging bag, 1b: Lower edge, 1l: Left side edge, 1r: Right side edge, 1t: Upper edge, 2: Front part, 2d: Lower front part, 2u: Upper front part, 3: Back part, 4: Sealing part, 4s: Side sealing part, 4t: Top sealing part, 5: Clasping part, 5b: Lower edge (root), 5t: Upper edge, 6: Side sealing part, 7: End sealing part, 7a: Inner edge, 7b: Outer edge, 8: Vapor release sealing part, 8a: Inner edge, 8b: Outer edge, 8c: Front end, 8d: First area, 8d1: Base part, 8d2: Protrusion, 8d3: Weak sealing area, 8e: Second area, 8f: Boundary line, 8g: Inner area, 8h: Outer area, 8i : Stepped portion, 8j: Lower end, 9: Membrane, 9a: Substrate layer, 9b: Sealant layer, 10: Unsealed portion, 12: Cutout, 20: Sealing strip, 21: First sealing unit, 21a: First vapor release seal forming portion, 21a1: First region forming portion, 21a2: Second region forming portion, 21a3: Base portion, 21a4: Protrusion, 21a5: Chamfered portion, 21b: End seal forming portion, 22: Second sealing unit, 22a: Second vapor release seal forming portion, 22a1: First region forming portion, 22a2: Second region forming portion, 22a3: Base portion, 22a4: Protrusion, 22a5: Chamfered portion, 22b: End seal forming portion.

Claims

1. A sealing strip for manufacturing packaging bags, characterized in that, The packaging bag is constructed by heat-sealing a film at the sealing portion. The sealing part has a vapor release sealing part that forms a vapor flow path as the internal pressure rises. The vapor release seal has a curved shape that bends toward the inside of the packaging bag. The vapor release seal includes a first region and a second region. The first region includes the curved front end. The second region is adjacent to the first region. The sealing strength of the first region is higher than that of the second region. The sealing strip has a vapor release seal forming portion for forming the vapor release seal. The vapor release seal forming portion has a first region forming portion for forming a first region and a second region forming portion for forming a second region, wherein the protrusion of the first region forming portion is greater than the protrusion of the second region forming portion.

2. The sealing strip according to claim 1, characterized in that, The packaging bag has a front section, which includes a lower front section and an upper front section. In the clasped portion formed by the partial overlap of the lower front portion and the upper front portion, the lower front portion and the upper front portion are heat-sealed at a pair of side sealing portions, a pair of end sealing portions, and the vapor release sealing portion. The side sealing portion is provided along the side edge of the clasped portion and is connected to the vapor release sealing portion via the end seal. The sealing strength of the end seal is higher than that of the first region. The sealing strip has an end seal forming portion for forming the end seal portion. The protrusion of the end seal forming portion is greater than the protrusion of the first region forming portion.

3. The sealing strip according to claim 1 or 2, characterized in that, It has a first sealing unit and a second sealing unit. When the vapor release sealing forming part is used as the first vapor release sealing forming part The first sealing unit has a first vapor release sealing forming part. The second sealing unit has a second vapor release seal forming portion for forming the vapor release seal portion. The line widths of the first vapor release seal forming part and the second vapor release seal forming part are different.

4. A method for manufacturing a packaging bag, characterized in that, The packaging bag is constructed by heat-sealing a film at the sealing portion. The sealing part has a vapor release sealing part that forms a vapor flow path as the internal pressure rises. The vapor release seal has a curved shape that bends toward the inside of the packaging bag. The vapor release seal includes a first region and a second region. The first region includes the curved front end. The second region is adjacent to the first region. The sealing strength of the first region is higher than that of the second region. The method for manufacturing the packaging bag includes a step of forming the vapor release seal by a sealing step comprising a first sealing step and a second sealing step. In the first sealing process, the membrane is heat-sealed using a first sealing unit having a first vapor release seal forming portion. In the second sealing process, the membrane is heat-sealed using a second sealing unit having a second vapor release seal forming portion. The line widths of the first vapor release seal forming part and the second vapor release seal forming part are different.

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