Method for making resealable packaging bags

Abstract

To enable a resealable packaging bag to be prepared by a simpler method.SOLUTION: A bag-making method of a resealable packaging bag provided with a font face part and a rear face part that is constituted by being connected in such a manner that at least one packaging film is bag-shaped and that overlap to be opposed to each other comprises the steps of: preparing the packaging film; sealing a side of the packaging film so as to be cylindrical; sealing an end on an opposite side of an end on a side where a resealable part is formed according to a cylindrical packaging film; and connecting the packaging film of the front face part with the packaging film of the rear face part by welding resin layers of the resealable film to form the resealable part. The packaging bag includes the resealable part provided near an opening formed during opening and having the resealable film including an adhesive layer and a pair of resin layers sandwiching a pair of main faces of the adhesive layer sandwiched between the front face part and the rear face part before opening.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a resealable packaging bag.

Background Art

[0002] Conventionally, resealable packaging bags have been studied. For example, in Patent Document 1, a method of manufacturing a strip film in which a chuck tape is welded to a packaging material film and manufacturing a resealable flat bag provided with a chuck tape near an opening from this strip film is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventionally studied methods, in order to reliably perform resealing with the chuck tape, it is necessary to accurately set the attachment position of the chuck tape. Further, since it is necessary to weld the chuck tape to both the front packaging material film and the back packaging material film, the manufacturing process may become complicated.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a technique capable of manufacturing a resealable packaging bag by a simpler method.

Means for Solving the Problems

[0006] To achieve the above objective, a method for making a resealable packaging bag according to one embodiment of the present disclosure is a method for making a resealable packaging bag comprising one or more packaging films joined together to form a bag, and including a front portion and a back portion that are superimposed facing each other, wherein the packaging bag includes a reseal portion provided near an opening formed when opened, in which a resealing film comprising an adhesive layer and a pair of resin layers sandwiching a pair of main surfaces of the adhesive layer is sandwiched between the front portion and the back portion before opening, and comprises preparing a packaging film, sealing the sides of the packaging film to form a tube, sealing the end of the tube-shaped packaging film opposite to the end on which the resealing portion is formed, and forming the resealing portion by welding the resin layers of the resealing film to join the packaging film of the front portion and the packaging film of the back portion.

[0007] According to the above method for manufacturing resealable packaging bags, a packaging bag with a resealable portion can be created by sealing the sides of the packaging film to form a tube, sealing the end of the tubular packaging film opposite to the end on which the resealable portion is formed, and welding the resin layer of the resealable film at the resealable portion to join the front packaging film and the back packaging film. Therefore, it becomes possible to manufacture resealable packaging bags in a simpler way.

[0008] Here, the packaging film includes a base film and a resealing film laminated over the entire surface of one main surface of the base film, and in forming the packaging film into a tubular shape, the packaging film may be formed into a tubular shape such that the resealing film is on the inside.

[0009] By adopting the above configuration, it becomes possible to form a resealable portion by welding without requiring precise positional adjustment of the welding location for forming the resealable portion. This makes it possible to manufacture resealable packaging bags in a simpler way.

[0010] The packaging film includes a base film and a resealing film welded to one main surface of the base film at a position corresponding to the resealing portion, which is at least one of the packaging films that are facing each other when resealed. In forming the packaging film into a tubular shape, the packaging film may be formed into a tubular shape such that the resealing film is on the inside.

[0011] As described above, when creating a packaging bag using a packaging film that includes a resealing film welded to a position corresponding to the resealing portion, which is at least one of the packaging films that are arranged opposite each other when resealed, it becomes possible to form the resealing portion while suppressing the amount of resealing film used, thus making it possible to manufacture resealable packaging bags simply and inexpensively.

[0012] The embodiment may further include sealing the end on the side where the resealing portion is formed. In this embodiment, forming the resealing portion may be performed after sealing the end on the side where the resealing portion is formed and sealing the end on the opposite side from the end on the side where the resealing portion is formed.

[0013] With this configuration, after sealing both ends of the tubular packaging film, welding is performed to form a resealing section. By manufacturing the packaging bag in this order, the contents scattered This allows for the proper formation of the resealed portion while suppressing the possibility of deformation. [Effects of the Invention]

[0014] This disclosure provides a technology that enables the manufacture of resealable packaging bags in a simpler manner. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a diagram illustrating the schematic configuration of a packaging bag according to one embodiment. [Figure 2] Figure 2 is a diagram illustrating the layer structure of the packaging bag. [Figure 3]Figs. 3(a) and 3(b) are diagrams for explaining the opened state of the packaging bag. [Figure 4] Fig. 4 is a flowchart for explaining the bag-making method of the packaging bag according to one embodiment. [Figure 5] Fig. 5 is a schematic diagram of an example of a bag-making machine. [Figure 6] Fig. 6 is a diagram for explaining the evaluation result of the resealing strength. [Figure 7] Fig. 7 is a diagram for explaining the evaluation result of the resealing strength. [Figure 8] Fig. 8 is a diagram for explaining another example of the packaging bag. [Figure 9] Fig. 9 is a diagram for explaining an example of a packaging film for manufacturing the packaging bag shown in Fig. 8. [Figure 10] Fig. 10 is a diagram for explaining another example of the packaging bag. [Figure 11] Fig. 11 is a diagram for explaining another example of the packaging bag.

Embodiments for Carrying out the Invention

[0016] Hereinafter, embodiments for implementing the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted.

[0017] In the following embodiments, a bag-making method for a resealable packaging bag will be described. First, a typical resealable packaging bag will be described, and then the bag-making method of the packaging bag will be described.

[0018] [Resealable Packaging Bag] Referring to Figs. 1 and 2, the configuration of an example of the resealable packaging bag 1 will be described. The packaging bag 1 is a so-called pillow bag, which is a bag formed in a tubular shape by bonding the ends of one packaging film. The packaging bag 1 is formed by arranging a packaging film 10 composed of a base film 11 and a resealing film 20 in a tubular shape with the resealing film 20 on the inside. Further, as shown in Fig. 2, the packaging bag 1 has a front surface portion 1a and a back surface portion 1b.

[0019] The packaging bag 1 has a main body portion 2 in which the contents are contained, an upper end seal portion 3 formed at the upper end of the main body portion 2, a lower end seal portion 4 formed at the lower end of the main body portion 2, a back seal portion 5 extending in the vertical direction, and a reseal portion 6 formed above the main body portion 2 and below the upper end seal portion 3.

[0020] The shape of the main body 2 is not particularly limited, and for example, it may be rectangular when viewed from a predetermined direction. At least a portion of the outer surface of the main body 2 is printed (not shown). The main body 2 may contain, for example, a specific gas such as nitrogen in addition to the contents. The upper end seal portion 3, the lower end seal portion 4, and the back seal portion 5 are the parts where a part of the packaging film 10 is bonded to another part. In the upper end seal portion 3, the lower end seal portion 4, and the back seal portion 5, a part of the packaging film 10 and another part are in close contact with each other. The upper end seal portion 3, the lower end seal portion 4, and the back seal portion 5 are formed, for example, by heating and compressing a part of the packaging film 10 and another part (i.e., heat sealing). The reseal portion 6 is sealed before the packaging bag 1 is opened, but it is easier for the user to open than the seal portion described above. This point will be described later.

[0021] The packaging film 10 is a film constructed by laminating a base film 11 and a resealing film 20.

[0022] The base film 11 is, for example, a flexible, substantially rectangular sheet. The thickness of the base film 11 may be, for example, about 9 μm to 200 μm.

[0023] Although not shown, the base film 11 may be constructed by laminating a base layer and an intermediate layer in that order from the outside to the inside of the packaging bag 1.

[0024] The base layer may consist of, for example, a plastic film, paper, or nonwoven fabric, either alone or in combination of two or more of these. The plastic film may be, for example, a polyester film, polypropylene (PP) film, polystyrene film, nylon film, polycarbonate film, polyethylene terephthalate (PET) film, polyacrylonitrile film, or polyimide film. As long as the plastic film exhibits the required mechanical strength and dimensional stability, there are no particular limitations on its material, composition, or manufacturing method. For example, the plastic film may be made of a biaxially oriented film. A metal vapor-deposited layer, such as aluminum, may be formed on the surface of the plastic film. The paper may be, for example, fine paper, single-sided art paper, coated paper, cast-coated paper, or imitation paper. The paper used for the base layer may be appropriately selected based on its mechanical strength and suitability for bag making.

[0025] The intermediate layer may be arranged, for example, to improve the various physical properties of the base film 11. These properties include, for example, rigidity, drop strength, puncture strength, gas (e.g., water vapor, oxygen gas, etc.) barrier properties, and aesthetic properties. To improve rigidity, drop strength, puncture strength, etc., the intermediate layer may be composed of, for example, a nylon film or a polyester film. To improve water vapor barrier properties, the intermediate layer may be composed of, for example, aluminum foil or other metal foil, a plastic film with a metal such as aluminum vapor-deposited on it (e.g., a polyester film), or a plastic film with an inorganic oxide vapor-deposited on it (e.g., a polyester film). The inorganic oxide may be, for example, a metal oxide such as silicon oxide, aluminum oxide, magnesium oxide, calcium oxide, potassium oxide, tin oxide, sodium oxide, boron oxide, titanium oxide, lead oxide, zirconium oxide, or yttrium oxide. Of these, silicon oxide, aluminum oxide, magnesium oxide, etc. may be selected as the inorganic oxide, taking into consideration productivity and cost. To improve aesthetic properties, the intermediate layer may be composed of, for example, a polyester film having an aluminum vapor-deposited layer.

[0026] The base layer and the intermediate layer may be joined by an adhesive. The adhesive may be, for example, a dry laminating adhesive. Examples of adhesive types include two-component curing urethane adhesives, polyester urethane adhesives, polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, and epoxy adhesives. When a dry laminating adhesive is used, the two layers may be bonded together using the dry lamination method.

[0027] The resealable film 20 is provided on the inner surface of the base film 11, as illustrated in Figure 2. In the packaging bag 1 illustrated in Figures 1 and 2, the resealable film 20 is provided over the entire inner surface of the base film 11. The resealable film 20 is constructed by laminating a polyolefin layer 21, an adhesive layer 22, and a polyolefin layer 23 in this order from the outside to the inside of the packaging bag 1. The polyolefin layer 21, the adhesive layer 22, and the polyolefin layer 23 may be laminated. Various known lamination methods (e.g., dry lamination, extrusion lamination) may be used. The resealable film 20 may be, for example, "Diamilon® MF-RE" manufactured by Mitsubishi Chemical Corporation. The thickness of the resealable film 20 may be, for example, 40 μm to 80 μm, of which the adhesive layer 22 may be 5 μm to 35 μm thick.

[0028] Furthermore, the resealable film 20 may have layers made of other resins, such as polyethylene, instead of the polyolefin layers 21 and 23. Also, the type of adhesive used in the adhesive layer 22 is not particularly limited, and various adhesives can be used as long as the resealability described later is achieved.

[0029] The packaging bag 1 is manufactured by forming a pillow bag from a packaging film 10 which is formed by laminating the above-mentioned base film 11 and resealing film 20. The bonding state at the resealing part 6 at this time will be explained. In Figure 2, the packaging film 10 that constitutes the front side will be described as packaging film 10A, and the packaging film 10 that constitutes the back side will be described as packaging film 10B.

[0030] As shown in Figure 2, in the resealing section 6, the resealing film 20 of the front packaging film 10A is joined to the resealing film 20 of the back packaging film 10B near the upper end seal section 3. The upper end seal section 3 is the location that becomes the opening when the packaging bag 1 is opened. Therefore, the resealing section 6 is provided near the opening when the packaging bag 1 is opened. In the resealing section 6, for example, the polyolefin layer 23 of the resealing film 20 provided on the inner surface of the packaging film 10A and the polyolefin layer 23 of the resealing film 20 provided on the inner surface of the packaging film 10B are joined by heat fusion.

[0031] As described above, the resealable portion 6, formed by heat-sealing the two polyolefin layers 23, extends from the left end to the right end along the left-right direction of the packaging bag near the upper end seal portion 3, as shown in Figure 1. The width (size in the vertical direction) of the resealable portion 6 may be, for example, 3 mm or more, or 20 mm or less. The width of the resealable portion 6 can be appropriately changed considering the shape and size of the bag.

[0032] Furthermore, the joining state of the upper end seal portion 3 and the lower end seal portion 4 is the same as that of the reseal portion 6 described above. That is, the polyolefin layer 23 of the reseal film 20 provided on the inner surface of the packaging film 10A and the polyolefin layer of the reseal film 20 provided on the inner surface of the packaging film 10B 23 The two are joined together by heat fusion.

[0033] As shown in Figure 1, the upper end seal portion 3 is sealed when the packaging bag 1 is made. However, depending on the bag-making method, the upper end seal portion 3 may not be provided, and the area above the reseal portion 6 may be open. When the upper end seal portion 3 and the reseal portion 6 are provided, an area is secured between the upper end seal portion 3 and the reseal portion 6 in which the packaging film 10A and the packaging film 10B are not heat-sealed. This makes it easy to re-open the reseal portion 6.

[0034] When opening the above-mentioned packaging bag 1, the user grasps the packaging films 10A and 10B sealed at the upper end seal portion 3 and applies force to pull them apart. At this time, first, the upper end seal portion 3 breaks, separating the upper end seal portion 3 into packaging film 10A and packaging film 10B. Subsequently, if force is continued to be applied, the reseal portion 6 also separates into packaging film 10A and packaging film 10B in the same way as the upper end seal portion 3. The separation of packaging film 10A and packaging film 10B at the reseal portion 6 will be explained with reference to Figure 3(a).

[0035] As shown in Figure 3(a), when a force is applied to the resealing portion 6 that pulls the packaging films 10A and 10B apart, the polyolefin layer 23 of the packaging film 10A ruptures at the upper end X1 of the resealing portion 6. Subsequently, the polyolefin layer 23 peels away from the adhesive layer 22 (so-called interlayer delamination) between the adhesive layer 22 and the polyolefin layer 23 of the packaging film 10A, exposing the adhesive layer 22 from the polyolefin layer 23. Furthermore, the polyolefin layer 23 of the packaging film 10A ruptures near the edge X2 on the lower side of the resealing portion 6 (the side of the main body 2 of the packaging bag 1). As a result, the packaging films 10A and 10B separate, and the packaging bag 1 is opened.

[0036] On the other hand, after opening the packaging bag 1, when the user presses the packaging film 10A and packaging film 10B together in the resealing section 6, the adhesive layer 22 of the exposed packaging film 10A adheres to the polyolefin layer 23. This reseals the resealing section 6 of the packaging bag 1. In other words, the portion of the resealing film 20 that was initially heat-sealed as the resealing section 6 functions as a resealing section that reseals the packaging bag 1. Subsequently, the adhesive layer 22 of the exposed packaging film 10A separates from or adheres to the polyolefin layer 23, making it possible to repeatedly open and reseal the packaging bag 1.

[0037] Note that the state of the resealing portion 6 and upper end seal portion 3 shown in Figure 3(a) is just an example and is not limited to this configuration. For example, when opening the packaging bag 1, the polyolefin layer 21 of the packaging film 10B may rupture near the edge X1 of the resealing portion 6. In this case, the adhesive layer 22 of the packaging film 10B may peel off from the polyolefin layer 21 (so-called interlayer delamination), exposing the adhesive layer 22 from the polyolefin layer 21. Furthermore, the polyolefin layer 21 of the packaging film 10B may rupture near the edge X2.

[0038] Furthermore, as shown in Figure 3(b), the adhesive layer 22 of the packaging film 10A or packaging film 10B may be exposed by agglomeration and peeling within its own layer. Even in such a case, similar to the state shown in Figure 3(a), the packaging bag 1 can be opened and resealed repeatedly after opening due to the separation and adhesion of the peeled adhesive layer 22.

[0039] As mentioned above, the upper end seal portion 3 is also sealed by heat fusion, so structurally it is possible to repeatedly open and reseal it. However, as mentioned above, by ensuring an area on the end side from the reseal portion 6 where the packaging film 10A and packaging film 10B are not heat-fused, it is possible to easily reopen it.

[0040] [Method for making packaging bags] Next, the method for making packaging bags will be explained with reference to Figures 4 and 5. Figure 4 is a flowchart illustrating the overview of the bag-making method, and Figure 5 is a perspective view illustrating the overview of the packaging machine used for bag making.

[0041] As shown in Figure 4, the method for making a packaging bag includes preparing a packaging film (step S01), sealing the sides of the packaging film to form a cylindrical shape (step S02), sealing the ends of the packaging film (step S03), welding the resealing portion (step S04), and cutting the packaging bag (step S05).

[0042] Preparing the packaging film (S01) involves preparing the film to be used for packaging bag 1. Specifically, this is the process of preparing a packaging film 10 in which the base film 11 and the resealing film 20 described above are laminated. The packaging film 10 is prepared, for example, in roll form. Note that preparing the packaging film (S01) may also include, for example, creating the packaging film 10 by laminating the base film 11 and the resealing film 20 together. Thus, preparing the packaging film (S01) is not limited to attaching the roll-shaped packaging film 10 to the packaging machine 90, but may also include creating the packaging film 10 from the base film 11 and the resealing film 20.

[0043] The sealing of the sides of the packaging film (S02), sealing of the edges of the packaging film (S03), welding of the resealing portion (S04), and cutting of the packaging bag (S05) are performed by the packaging machine shown in Figure 5. The packaging machine 90 shown in Figure 5 is a modified version of a so-called vertical pillow filling packaging machine.

[0044] The packaging machine 90 consists of a film unwinding section 91, a conveying section 92, a bag-making section 93, a filling section 94, and a separation section 95.

[0045] The unwinding unit 91 unwinds the packaging film 10, which is wound into a roll. The transport unit 92 has a guide roll 92a, which transports the packaging film 10 to the bag-making unit 93. The packaging film 10, which is wound into a roll, is attached to a predetermined position on the packaging machine 90 and supplied to the packaging machine 90 by being unwound by the unwinding unit 91. In other words, the method for making a packaging bag may include supplying the packaging film 10 by unwinding the roll of packaging film 10 and transporting the packaging film 10 in the packaging machine 90, in addition to preparing the packaging film (S01).

[0046] The bag-making section 93 has a mechanism for forming a cylindrical packaging bag body by joining the widthwise ends of the packaging film 10 conveyed by the conveying section 92 to form a back seal section 5 that extends in the longitudinal direction as shown in the figure, and a mechanism for sealing the cylindrical plastic film in the transverse direction (widthwise). Specifically, the vertical sealing is performed by a vertical seal bar 93a, and the transverse sealing is performed by a transverse (widthwise) seal bar 93b. The bag-making section 93 may also be provided with guide bars to deform the packaging film 10 in order to weld the widthwise ends together with the vertical seal bar 93a. The sealing by the seal bar 93a corresponds to sealing the sides of the packaging film (S02). Since the packaging film 10 becomes cylindrical by forming the back seal section 5, the sides of the packaging bag are substantially sealed.

[0047] The seal bar 93b, which seals laterally, is formed by sealing the lower end seal portion 4 at the bottom of the packaging bag before the contents are filled, and after the contents are filled, it seals the top of the packaging bag to form the upper end seal portion 3. When welded by the seal bar 93b, the lower end seal portion 4 of the upper bag and the upper end seal portion 3 of the bag below it are in a continuous state. The sealing by the seal bar 93b corresponds to sealing the end of the packaging film 10 (S03).

[0048] Furthermore, the bag-making section 93 is provided with a seal bar 93c below the seal bar 93b for forming a resealing section 6. The seal bar 93b seals the upper end seal section 3 and Upper bag The lower end seal portion 4 is sealed and the lower part of the upper end seal portion 3 is welded at the same time. This forms a resealed portion 6. The length of the seal bar 93c is set according to the shape of the resealed portion 6 (especially the width in the vertical direction). The seal by the seal bar 93c corresponds to welding the resealed portion (S04).

[0049] The filling section 94 has the function of inserting a predetermined amount of contents into the inside of a packaging bag, which has a back seal section 5 welded by a seal bar 93a and a lower end seal section 4 welded by a seal bar 93b.

[0050] The separation unit 95 separates the sealed portion welded by the seal bar 93b, thereby separating the packaging bags 1 individually. This forms the packaging bags. The method for separating the sealed portion is not particularly limited, but known cutting and separation methods can be used.

[0051] [Heat seal strength of packaging bags] When the packaging bag 1 is opened, the strength at which the base film 11 and the polyolefin layer 21 of the packaging film 10A and 10B separate at the resealing portion 6 will be referred to as the heat seal strength SH1. The heat seal strength SH1 is the sum of the interlayer adhesion strength between the base film 11 and the polyolefin layer 21 of the outer packaging film 10A, and the rupture strength of the polyolefin layers 21, 23 and the adhesive layer 22 in the thickness direction. When the packaging bag 1 is opened, the strength at which the polyolefin layer 21 and the adhesive layer 22 separate at the resealing portion 6 will be referred to as the heat seal strength SH2. That is, the heat seal strength SH2 is the sum of the interlayer adhesion strength between the polyolefin layer 21 and the adhesive layer 22, and the rupture strength of the polyolefin layer 23 and the adhesive layer 22 in the thickness direction. Furthermore, when the packaging bag 1 is opened, the strength at which the adhesive layer 22 and the polyolefin layer 23 separate at the resealing portion 6 will be referred to as the heat seal strength SH3. In other words, the heat seal strength SH3 is the sum of the interlayer adhesion strength between the adhesive layer 22 and the polyolefin layer 23, and the breaking strength of the polyolefin layer 23 in the thickness direction. In this specification, "heat seal strength" refers to the value measured in accordance with the "heat seal strength test of bags" as defined in JIS Z 0238:1998 "Test methods for heat-sealable flexible packaging bags and semi-rigid containers".

[0052] Here, the heat seal strengths SH2 and SH3 (heat seal strength of the adhesive layer 22 in the resealed portion 6) may be smaller than the heat seal strength SH1 (heat seal strength of layers other than the adhesive layer 22 in the resealed portion). In this case, when opening the resealed portion 6, the adhesive layer 22 is more likely to peel off first in the bonding region R, making it easier to open near the adhesive layer 22.

[0053] The heat seal strengths SH2 and SH3 may be, for example, 0.5N / 15mm to 20N / 15mm, 0.5N / 15mm to 15N / 15mm, or 0.5N / 15mm to 10N / 15mm. When the heat seal strengths SH2 and SH3 are 0.5N / 15mm or higher, the adhesion between the adhesive layer 22 and the polyolefin layers 21 and 23 tends to be maintained. When the heat seal strengths SH2 and SH3 are 20N / 15mm or lower, the user tends to be able to open the resealed portion 6 with moderate force by pinching the area near the upper seal portion 3 of the packaging bag 1.

[0054] Furthermore, the heat seal strengths SH2 and SH3 may differ between the region R1 (see Figure 2) below the resealing portion 6 (on the main body 2 side) and the region R2 (see Figure 2) above it. Specifically, the heat seal strengths SH2 and SH3 in region R2 are greater than those in region R2. For example, the heat seal strengths SH2 and SH3 in region R1 may be 5N / 15mm or more and 20N / 15mm or less. For example, the heat seal strengths SH2 and SH3 in region R2 may be 0.5N / 15mm or more and less than 5N / 15mm. When the heat seal strengths SH2 and SH3 in region R1 are 5N / 15mm or more, unintended leakage of the contents of the packaging bag 1 tends to be prevented. When the heat seal strengths SH2 and SH3 in region R1 are 20N / 15mm or less, the user tends to be able to open the resealing portion 6 by pinching the packaging bag 1 with moderate force. When the heat seal strengths SH2 and SH3 in region R2 are 0.5 N / 15 mm or higher, the sealing state of region R1 in the resealed area tends to be maintained more easily. When the heat seal strengths SH2 and SH3 in region R2 are 5 N / 15 mm or lower, users tend to be able to open region R2 in the resealed area with light force.

[0055] The difference between the heat seal strengths SH2 and SH3 and the heat seal strength of the other layers (e.g., heat seal strength SH1) may be, for example, 5N / 15mm or more, 10N / 15mm or more, or 15N / 15mm or more. Note that the heat seal strengths SH2 and SH3 may decrease with repeated opening and resealing of the resealing section 6 of the packaging bag 1. Therefore, at least at the first resealing, the heat seal strengths SH2 and SH3 may meet the above numerical range (0.5N / 15mm to 20N / 15mm). The heat seal strengths SH2 and SH3 at the first opening of the packaging bag 1 may be, for example, 3N / 15mm to 20N / 15mm. The heat seal strengths SH2 and SH3 at the time of resealing may be, for example, 0.5N / 15mm to 10N / 15mm. Having the heat seal strength within the above range allows for proper sealing at the resealing section 6 and facilitates opening by the user. Furthermore, if the heat seal strength during resealing is maintained even after opening and resealing approximately five times, then the packaging bag can be considered resealable and highly convenient for the user.

[0056] [Reseal strength after repeated use] The reseal strength of the above-mentioned packaging bag was evaluated. Reseal strength represents the load exerted by the user when opening the resealable portion 6 of the packaging bag 1, and corresponds to the heat seal strengths SH2 and SH3 described above.

[0057] For evaluation purposes, a flat pillow bag measuring 230 mm in length and 100 mm in width was prepared, with a resealable section 6 width (vertical length) set to 5 mm. The packaging film 10 constituting the packaging bag was prepared as a multilayer film containing a transparent vapor-deposited PET film (thickness 12 μm) and nylon (thickness 15 μm) as the base film 11, and B-pack's "51900RC" (thickness 60 μm) was prepared as the resealable film 20. These were laminated together to create a packaging film 10 with a thickness of 90 μm.

[0058] A sample piece measuring 15 mm horizontally was cut from the packaging bag described above, and the reseal strength when the unopened resealable section 6 was opened was defined as the reseal strength for the 0th attempt. Subsequently, the resealable section 6 of the sample piece was repeatedly sealed by pressing it, and then opened again. The amount of force required to open it each time was measured as the reseal strength from the 1st attempt onward. The pressing force when sealing the resealable section 6 was 66 gf / mm². 2 The value was fixed at ×5sec. Note that "reseal strength" is the value measured in accordance with the "heat seal strength test of bags" as defined in JIS Z 0238:1998 "Test methods for heat-sealable flexible packaging bags and semi-rigid containers". In other words, "reseal strength" in this evaluation is the value measured using the same method as the "heat seal strength" described above.

[0059] The measurement results obtained by the above procedure are shown in Table 1. The unit of reseal strength shown in Table 1 is "N / 15mm". Figure 6 shows the measurement results of reseal strength from the 0th to the 6th time, and Figure 7 shows the change in reseal strength from the 0th to the 30th time when resealing and opening were repeated up to 30 times.

[0060] [Table 1]

[0061] As shown in Figure 6, the seal strength was high during the first opening (0 times), but it was confirmed that the seal strength decreased to 1.1 N / 15 mm or less after the first opening, i.e., after the package had been sealed once.

[0062] On the other hand, as shown in Figure 7, although the reseal strength gradually decreases with repeated resealing and opening, the seal strength remained above 0.5 N / 15 mm even after 30 repetitions, confirming that stable seal strength can be obtained even with repeated resealing.

[0063] [Effect] According to the above method for manufacturing resealable packaging bags, a packaging bag with a resealable portion 6 can be created by sealing the sides of the packaging film 10 to form a tube, sealing the lower end seal portion 4, which is the end opposite to the end on which the resealable portion 6 is formed, and welding the polyolefin layer 23, which is the resin layer of the resealable film 20, to join the front packaging film 10 and the back packaging film 10. Therefore, it is possible to manufacture resealable packaging bags in a simpler way.

[0064] In this case, the packaging film 10 may include a base film 11 and a resealable film 20 laminated over the entire surface of one main surface of the base film 11. Furthermore, when forming a cylindrical shape, the packaging film 10 may be made cylindrical such that the resealable film 20 is on the inside. This configuration eliminates the need for precise positional adjustments regarding the welding location for forming the resealable portion 6, making it possible to form the resealable portion 6 by welding, thus enabling the manufacture of resealable packaging bags in a simpler manner.

[0065] [Effect] Furthermore, as with the packaging bag described above, the end on the side where the resealable portion 6 is formed may be sealed. In this case, forming the resealable portion 6 may be performed after sealing the end on the side where the resealable portion 6 is formed and sealing the end on the opposite side from the end on which the resealable portion 6 is formed. With this configuration, welding to form the resealable portion is performed after sealing both ends of the tubular packaging film. By manufacturing the packaging bag in this order, the contents scattered This allows for the proper formation of the resealing portion 6 while suppressing the possibility of deformation.

[0066] [Differentiation] The disclosures herein should be considered in all respects to be illustrative and not restrictive. Various omissions, substitutions, and modifications may be made to the above examples without departing from the claims and the gist thereof.

[0067] For example, the resealing film 20 may be provided in the region of the inner surface of the packaging film 10 that will become the resealing portion 6. In this case as well, the adhesive layer 22 may be exposed by peeling between the polyolefin layer 21 or polyolefin layer 23, or it may be exposed by agglomeration and peeling within its own layer. In the packaging bag 1A illustrated in Figure 8, the resealing film 20 may be provided only in the bonding region R on the inner surface of the base film 11. In this case, since the resealing portion is provided in the minimum necessary area, it is possible to manufacture a resealable packaging bag 1 at low cost. When the resealing film 20 is provided on a part of the inner surface of the base film 11, the base film 11 constituting the packaging films 10A and 10B may further include a sealant layer 11a provided on the inner surface of the base layer or intermediate layer, as illustrated in Figure 8.

[0068] As shown in Figure 8, if the resealable film 20 is formed only in the region that becomes the resealable portion 6, the packaging film 10X shown in Figure 9 can be used. Figure 9 shows a state in which a portion of the rolled packaging film 10X has been pulled out.

[0069] The packaging film 10X has a base film 11 covering its entire surface. On top of that, the resealing film 20 is placed only in the area that constitutes the resealing section 6. With the packaging film 10X, the length L1 in the vertical direction (up and down direction) of the packaging bag to be manufactured using this film is predetermined, as is the placement of the resealing section 6 in the vertical direction (up and down direction) of the packaging bag. The resealing film 20 is then placed at a predetermined length L2 from the top edge of the packaging bag. The placement of the resealing film 20 is also determined considering the molding process during packaging. In the example shown in Figure 9, the dashed lines s1 and s2 shown in the length direction of the packaging film 10X represent the folded parts at the lateral edges of the packaging bag. Therefore, as shown in Figure 9, by placing the resealing film 20 in the area between the dashed lines s1 and s2 within the area that will become the resealing section 6 and fixing it to the base film 11, it is possible to create a packaging bag 1A in which the resealing film 20 is placed only in the position that will become the resealing section 6, as shown in Figure 8, using the packaging machine 90 described above.

[0070] As described above, when creating a packaging bag using a packaging film 10X that includes a resealing film 20 welded to a position corresponding to the resealing portion 6, which is at least one of the packaging films that are arranged opposite each other when resealing, it becomes possible to form the resealing portion 6 while suppressing the amount of resealing film 20 used, thus making it possible to manufacture resealable packaging bags simply and inexpensively.

[0071] Furthermore, although the above embodiment described the case where the packaging bag 1 is a so-called pillow bag, the type of resealable packaging bag is not limited to pillow bags and can be applied to other packaging bags that can be manufactured with the vertical pillow packaging machine shown in Figure 5, etc. Also, resealable packaging bags can be created by using a horizontal pillow packaging machine instead of a vertical pillow packaging machine. The resealable packaging bag described in this embodiment requires the resealable portion to be welded and sealed once, and by opening the resealable portion, the adhesive layer 22 is exposed and it becomes possible to reseal it. In other words, whether it is the vertical pillow packaging machine or the horizontal pillow packaging machine described above, as long as it has a mechanism that can seal the resealable portion in the same way as sealing the ends, it is possible to create a packaging bag that has the same function as the packaging bag 1 described in this embodiment. Moreover, even with a three-side seal packaging machine or the like, which is not a so-called pillow packaging machine, packaging bags with a resealable portion can be manufactured in the same way as the above-described packaging bag.

[0072] Referring to Figures 10 and 11, an example of a packaging bag with a different structure from the packaging bag 1 described in the above embodiment will be explained. Figures 10 and 11 show typical examples of packaging bags that can be manufactured with a general vertical pillow packaging machine.

[0073] The packaging bag 1B shown in Figure 10 is an example of a so-called three-side seal bag, in which the top and bottom of the packaging bag are sealed, and instead of a back seal, there is a pair of side seals 7 on the sides of the main body 2. Furthermore, there is no top seal 3, and only a bottom seal 4 is provided. Thus, there may be cases where the top seal 3 is not provided.

[0074] In this type of packaging bag 1B, the same functionality as packaging bag 1 is achieved by providing a resealing section 6. Furthermore, packaging bag 1B can be manufactured using a vertical pillow packaging machine, just like packaging bag 1. Additionally, by adjusting the number and arrangement of seal bars 93a, a side seal section 7 can be provided, and by using seal bar 93c, a resealing section 6 can be formed. Furthermore, by changing the configuration of the separation section 95, a configuration without an upper end seal section 3 above the resealing section 6 can be realized. However, the shape of packaging bag 1B, which is a three-sided bag, may be changed to a four-sided bag that also includes an upper end seal section 3.

[0075] The packaging bag 1C shown in Figure 11 is a so-called gusseted bag (a bag with a folded gusset). The packaging bag 1C consists of a surface part 10a and packaging bag 1 C The back surface portion 10b that constitutes the back surface, and the packaging bag 1 C The left side portion 10c that constitutes the left side of the packaging bag 1 C It may also include a right side portion 10d that constitutes the right side of the packaging bag 1C. The packaging bag 1C may also be provided with a lower end seal portion 4 and a back seal portion 5. The lower end seal portion 4 may extend in the left-right direction at the bottom and join the front portion 10a, the back portion 10b, the left side portion 10c and the right side portion 10d.

[0076] In this case, the resealing portion 6 may extend around the entire circumference of the front portion 10a, back portion 10b, left side portion 10c, and right side portion 10d on the upper end side of the packaging bag 1C. Alternatively, the resealing portion 6 may extend at least upward along the left-right direction from the left side portion 10c to the right side portion 10d on the inner surface of the packaging film 10, and also along the left-right direction on the inner surface of the packaging film 10 from the left side portion 10c to the right side portion 10d.

[0077] When opening the above packaging bag 1C, the user grasps the front part 10a and the back part 10b and applies force to pull them apart. This separates the front part 10a and the back part 10b, and the packaging bag 1C is opened. CWhen resealing, the left side portion 10c and the right side portion 10d are folded inward, and the front portion 10a and the back portion 10b are pressed against each other. This causes the exposed adhesive layer 22 to adhere to the other, and the resealing portion 6 of the packaging bag 1 is resealed. As a result, the packaging bag 1C can be resealed including the left side portion 10c and the right side portion 10d that have been folded inward. 、 Compared to gusseted bags with a zipper near the opening, this design allows for a larger opening when opened.

[0078] Furthermore, the method for manufacturing the packaging bags can also be modified as appropriate. For example, in the above embodiment, the formation of the resealing portion 6 by welding was described as being performed after the formation of the upper end seal portion 3 and the lower end seal portion 4, but this order can be changed as appropriate. For example, in a horizontal pillow packaging machine, the end sealing process may be performed later. The order of the procedure for forming the resealing portion 6 and the end sealing may also be changed. [Explanation of Symbols]

[0079] 1, 1A, 1B, 1C... Packaging bag, 3... Top seal, 4... Bottom seal, 5... Back seal, 6... Re-sealing section, 10, 10A, 10B, 10X... Packaging film, 10a... Front surface, 10b... Back surface, 11... Base film, 20... Re-sealing film, 21, 23... Polyolefin layer, 22... Adhesive layer.

Claims

1. A method for making a resealable packaging bag, comprising a packaging film joined together to form a bag shape, and including a front portion and a back portion that are overlapped and facing each other, The packaging bag includes a resealing portion provided near the opening formed when opened, in which, before opening, a resealing film comprising an adhesive layer and a pair of resin layers sandwiching a pair of main surfaces of the adhesive layer is sandwiched between the front portion and the back portion. The preparation of the aforementioned packaging film, The sides of the aforementioned packaging film are sealed to form a cylindrical shape, In the aforementioned tubular packaging film, the end opposite to the end on which the resealing portion is formed is sealed, After sealing the opposite end, the resealing portion is formed by welding the resin layer of the resealing film to join the packaging film on the front surface and the packaging film on the back surface. A method for manufacturing packaging bags, including the method for manufacturing packaging bags.

2. The packaging film comprises a base film and a resealing film laminated over the entire surface of one main surface of the base film. The method for making a packaging bag according to claim 1, wherein the packaging film is made into a cylindrical shape such that the resealing film is on the inside.

3. The packaging film includes a base film and a resealing film welded to one main surface of the base film at a position corresponding to the resealing portion, which is at least one of the packaging films that are arranged facing each other when resealed. The method for making a packaging bag according to claim 1, wherein the packaging film is made into a cylindrical shape such that the resealing film is on the inside.

4. The method further includes sealing the end on the side where the resealing portion is formed, The method for making a packaging bag according to any one of claims 1 to 3, wherein forming the resealable portion is performed after sealing the end on the side where the resealable portion is formed and sealing the end on the opposite side from the end on the side where the resealable portion is formed.

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