JP7830902B2 - Resealable packaging bags - Google Patents

Description

This disclosure relates to resealable packaging bags.

Packaging bags that can be repeatedly opened and closed are known for purposes such as maintaining the condition of the contents contained inside the packaging bag. For example, Patent Document 1 discloses a packaging bag with a pair of male and female plastic zippers provided near the opening. Patent Document 2 discloses a packaging bag equipped with an adhesive seal portion for resealing an opened opening. This adhesive seal portion consists of an adhesive seal portion body and a release paper covering the seal portion body. When resealing an opened opening, the user peels the release paper from the seal portion body and attaches the exposed seal portion body to the surface of the packaging bag.

Japanese Patent Publication No. 2016-055902 Japanese Patent Publication No. 2014-205498

This disclosure describes a packaging bag that allows the user to easily open the resealed portion.

An example of a packaging bag is a resealable packaging bag constructed by joining one or more packaging films to form a bag shape, and including a front portion and a back portion that are overlapped and facing each other. The example packaging bag comprises a pair of first and second sides, a bottom connecting the first and second sides, an entrance located opposite the bottom, and a resealable joint area extending along a first direction from the first side to the second side near the entrance, where the first and second sides are aligned. The resealable joint area includes a first portion sandwiched between the front and back portions in the joint area when the entrance is sealed, and a second portion located in the joint area closer to the entrance than the first portion and adjacent to the first portion. The heat seal strength of the first portion is greater than that of the second portion.

The packaging bag described herein allows the user to easily open the resealed portion.

Figure 1 is a front view showing an example of a packaging bag. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. Figure 3 is a cross-sectional view showing an example of the packaging bag shown in Figure 1 with the opening opened. Figure 4 is a perspective view showing an example of a heat-sealing unit for a bag-making machine. Figure 5 is a perspective view showing another example of a heat-sealing unit for a bag-making machine. Figure 6 is a perspective view showing another example of a heat-sealing unit for a bag-making machine. Figure 7 is a cross-sectional view showing another example of the packaging bag from Figure 1 with the opening opened. Figure 8 is a cross-sectional view showing another example of a packaging bag. Figure 9 is a cross-sectional view showing another example of a packaging bag. Figures 10(a) to 10(f) are front views showing other examples of packaging bags. Figure 11 is a front view showing another example of a packaging bag. Figure 12 is a perspective view showing another example of a packaging bag. Figure 13 is a perspective view showing an example of the packaging bag from Figure 12 with the opening opened. Figure 14 is a perspective view showing another example of a packaging bag. Figure 15 is a perspective view showing an example of the packaging bag from Figure 14 with the opening opened.

In the following descriptions, the same reference numeral will be used for elements that are identical or have the same function, and redundant explanations will be omitted. Furthermore, in this specification, when referring to the top, bottom, right, and left of a figure, the direction of the reference numeral in the figure is used as the reference point.

[Composition of resealable packaging bags]
Referring to Figures 1 and 2, an example of the configuration of a resealable packaging bag 1 will be described. The packaging bag 1 is composed of multiple packaging films. In the example shown in Figures 1 and 2, the packaging bag 1 is constructed by overlapping a front packaging film 11 (front surface) and a back packaging film 12 (back surface) so that they face each other, with a resealing film 20 (resealing portion) sandwiched between them. The packaging bag 1 may, for example, have a rectangular shape overall.

As illustrated in Figure 1, the packaging bag 1 includes a left side portion 1L (first side portion), a right side portion 1R (second side portion), a bottom portion 1B, and an upper portion 1T. The left side portion 1L extends along the left edge of the packaging bag 1 in the vertical direction Ar1 (second direction). The right side portion 1R extends along the right edge of the packaging bag 1 in the vertical direction. The left side portion 1L and the right side portion 1R face each other in the left-right direction Ar2 (first direction), which is perpendicular to the vertical direction Ar1. The bottom portion 1B extends along the left-right direction Ar2 at the bottom edge of the packaging bag 1, connecting the lower end of the left side portion 1L and the lower end of the right side portion 1R. The upper portion 1T extends along the left-right direction Ar2 at the top edge of the packaging bag 1, connecting the upper end of the left side portion 1L and the upper end of the right side portion 1R. The bottom portion 1B and the upper portion 1T face each other in the vertical direction Ar1.

The front packaging film 11 and the back packaging film 12 are, for example, flexible, substantially rectangular sheets. The thickness of the front packaging film 11 and the back packaging film 12 may be, for example, about 30 μm to 200 μm. The front packaging film 11 and the back packaging film 12 are sealed (e.g., heat-sealed) to each other at the left side 1L, the right side 1R, and the bottom 1B. Specifically, the front packaging film 11 and the back packaging film 12 are provided with a sealed portion 31 (first sealed portion) at the left side 1L where they are sealed to each other, a sealed portion 32 (second sealed portion) at the right side 1R where they are sealed to each other, and a sealed portion 33 at the bottom 1B where they are sealed to each other.

As illustrated in Figures 1 and 2, the front packaging film 11 and the back packaging film 12 do not necessarily have to be sealed at the top 1T. Alternatively, as will be described later, the front packaging film 11 and the back packaging film 12 may be sealed at the top 1T (see Figure 11). The top 1T of the packaging bag 1 is provided with an opening OP that connects the inside and outside of the packaging bag 1 when it is opened. That is, the opening OP is located on the opposite side of the bottom 1B of the packaging bag 1 and functions as an outlet for removing the contents of the packaging bag 1 when it is opened.

The outer packaging film 11, although not shown in the figure, 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.

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 materials. The plastic film may be, for example, polyester film, polypropylene (PP) film, polystyrene film, nylon film, polycarbonate film, polyethylene terephthalate (PET) film, polyacrylonitrile film, or polyimide film. The material, composition, and manufacturing method of the plastic film are not particularly limited, as long as it exhibits the required mechanical strength and dimensional stability. 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.

The intermediate layer may be arranged, for example, to improve the various physical properties of the outer packaging film 11. These properties include, for example, rigidity, drop strength, puncture strength, gas (e.g., water vapor, oxygen gas) barrier properties, and aesthetic appeal. 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 (e.g., a polyester film), or a plastic film with an inorganic oxide vapor-deposited (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 productivity and cost into consideration. To improve aesthetic appeal, the intermediate layer may be composed of, for example, a polyester film having an aluminum vapor-deposited layer.

The base layer and the intermediate layer may be joined by an adhesive. The adhesive may be, for example, a dry lamination 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 using a dry lamination adhesive, the two layers may be bonded together using the dry lamination method.

The back packaging film 12, although not shown, may be constructed similarly to the front packaging film 11, with a base layer and an intermediate layer laminated in that order from the outside to the inside of the packaging bag 1. As illustrated in Figure 2, the back packaging film 12 may further include a sealant layer 12a provided on the inner surface of the base layer or intermediate layer. The sealant layer 12a may be provided over the entire inner surface of the base layer or intermediate layer, or it may be provided in the region where the seal portions 31-33 are formed. The sealant layer 12a may be bonded to the base layer or intermediate layer by the adhesive described above.

The sealant layer 12a may be configured to melt and fuse to other sheets upon heat. That is, the sealant layer 12a may be heat-sealable. The sealant layer 12a may be composed of, for example, a polyolefin resin. Examples of polyolefin resins include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate copolymer (EAA), ionomer, and polypropylene. When the above resins are used as the material for the sealant layer 12a, the sealant layer 12a may be formed by extruding the resin into a film. The sealant layer 12a may be a single layer or a multi-layered layer.

The resealing film 20 is provided on the inner surface of the outer packaging film 11, as illustrated in Figure 2. In the packaging bag 1 illustrated in Figures 1 and 2, the resealing film 20 is provided over the entire inner surface of the outer packaging film 11. The resealing film 20 is constructed by laminating a polyolefin layer 21 (first polyolefin layer), an adhesive layer 22, and a polyolefin layer 23 (second polyolefin layer) in this order from the outside to the inside of the packaging bag 1. That is, the polyolefin layer 21 is laminated to the outer packaging film 11. The adhesive layer 22 is laminated to the polyolefin layer 21. The polyolefin layer 21, the adhesive layer 22, and the polyolefin layer 23 may be laminated together by lamination. Various known lamination methods (e.g., dry lamination, extrusion lamination) may be used as the lamination method. The polyolefin layer 23 is laminated to the adhesive layer 22. The resealing film 20 may be, for example, "Diamilon® MF-RE" manufactured by Mitsubishi Chemical Corporation.

The resealing film 20 is joined to the back packaging film 12 in a joining region R near the entrance OP, as illustrated in Figure 2. For example, the polyolefin layer 23 and the sealant layer 12a of the resealing film 20 may be heat-sealed in the joining region R. The heat sealing of the polyolefin layer 23 and the sealant layer 12a may be performed after the contents are placed inside the packaging bag 1 through the entrance OP. In this case, the contents are sealed inside the packaging bag 1.

The joint region R extends along the left-right direction Ar2 from the left side 1L to the right side 1R near the entrance portion OP. The joint region R may also extend linearly along the left-right direction Ar2 from the left side 1L to the right side 1R near the entrance portion OP, as illustrated in Figure 1. The width of the joint region R (size in the vertical direction Ar1) may be, for example, approximately 5 mm or more, or approximately 20 mm or less.

The joining region R includes, as illustrated in Figures 1 to 3, region R1 (first region) extending along the left-right direction Ar2 and located on the bottom 1B side (opposite the entrance OP), and region R2 (second region) extending along the left-right direction Ar2 and located on the upper 1T side (entrance OP side). The width of region R1 (size in the vertical direction Ar1) may be greater than the width of region R2 (size in the vertical direction Ar1).

When opening the packaging bag 1 described above, the user grasps the front packaging film 11 and the back packaging film 12 at the opening OP and applies force to pull them apart. As illustrated in Figures 2 and 3, this first causes the polyolefin layer 23 to rupture near the edge X1 on the opening OP side of the joining region R. Subsequently, the polyolefin layer 23 delaminates from the adhesive layer 22 (so-called interlayer delamination), exposing the adhesive layer 22 from the polyolefin layer 23. Furthermore, the polyolefin layer 23 ruptures near the edge X2 on the opposite side of the opening OP (the side facing the internal space of the packaging bag 1). As a result, the front packaging film 11 and the back packaging film 12 separate at the opening OP, and the packaging bag 1 is opened. This makes it possible to remove the contents of the packaging bag 1 from the opening OP.

On the other hand, after opening the packaging bag 1, when the user presses the front packaging film 11 and the back packaging film 12 together at the opening OP, the exposed adhesive layer 22 adheres to the polyolefin layer 23. This reseals the opening OP of the packaging bag 1 at the joining region R. That is, the portion of the resealing film 20 in the joining region R functions as a resealing portion that reseals the opening OP of the packaging bag 1. Subsequently, the exposed adhesive layer 22 separates from or adheres to the polyolefin layer 23, allowing the opening OP of the packaging bag 1 to be opened and resealed repeatedly.

[Heat seal strength]
Here, the strength at which the outer packaging film 11 and the polyolefin layer 21 peel off at the resealing portion when the inlet OP is opened will be referred to as the heat seal strength SH1. That is, the heat seal strength SH1 is the sum of the interlayer adhesion strength between the outer packaging film 11 and the polyolefin layer 21, and the breaking strength of the polyolefin layers 21, 23 and the adhesive layer 22 in the thickness direction. The strength at which the polyolefin layer 21 and the adhesive layer 22 peel off at the resealing portion when the inlet OP is opened 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 breaking strength of the polyolefin layer 23 and the adhesive layer 22 in the thickness direction.

The strength at which the adhesive layer 22 and the polyolefin layer 23 separate at the resealing portion when the inlet OP is opened will be referred to as the heat seal strength SH3. That is, 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 rupture strength of the polyolefin layer 23 in the thickness direction. The strength at which the polyolefin layer 23 and the sealant layer 12a separate at the resealing portion when the inlet OP is opened will be referred to as the heat seal strength SH4. That is, the heat seal strength SH4 is the bonding strength between the polyolefin layer 23 and the sealant layer 12a.

The strength at which the sealant layer 12a and the back packaging film 12 (base layer or intermediate layer) separate at the resealing portion when the opening of the inlet OP is opened is referred to as the heat seal strength SH5. That is, the heat seal strength SH5 is the sum of the interlayer adhesion strength between the sealant layer 12a and the back packaging film 12, and the breaking strength of the sealant layer 12a 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."

Here, the heat seal strengths SH2 and SH3 (heat seal strength of the adhesive layer 22 in the resealed area) may be smaller than the heat seal strengths SH1, SH4, and SH5 (heat seal strength of layers other than the adhesive layer 22 in the resealed area). In this case, when opening the entrance portion OP, the adhesive layer 22 is more likely to peel off first in the bonding region R. Therefore, it becomes possible to open the entrance portion OP more reliably.

In configurations where the back packaging film 12 does not contain a sealant layer 12a, the strength at which the polyolefin layer 23 and the back packaging film 12 (base layer or intermediate layer) separate at the resealing portion when the inlet portion OP is opened is referred to as the heat seal strength SH6. That is, the heat seal strength SH6 is the interlayer adhesion strength between the polyolefin layer 23 and the back packaging film 12. Even in this case, the heat seal strengths SH2 and SH3 (heat seal strength of the adhesive layer 22 at the resealing portion) may be smaller than the heat seal strengths SH1 and SH6 (heat seal strength of layers other than the adhesive layer 22 at the resealing portion).

The heat seal strengths SH2 and SH3 may be, for example, 0.5 N/15 mm to 20 N/15 mm, 0.5 N/15 mm to 15 N/15 mm, or 0.5 N/15 mm to 10 N/15 mm. When the heat seal strengths SH2 and SH3 are 0.5 N/15 mm or higher, the adhesion between the adhesive layer 22 and the polyolefin layers 21 and 23 tends to be easily maintained. When the heat seal strengths SH2 and SH3 are 20 N/15 mm or lower, users tend to be able to open the opening OP by pinching it with their fingers and applying moderate force.

The heat seal strengths SH2 and SH3 in region R1 are greater than the heat seal strengths SH2 and SH3 in region R2. The heat seal strengths SH2 and SH3 in region R1 may be, for example, 5 N/15 mm or more and 20 N/15 mm or less. The heat seal strengths SH2 and SH3 in region R2 may be, for example, 0.5 N/15 mm or more and less than 5 N/15 mm. When the heat seal strengths SH2 and SH3 in region R1 are 5 N/15 mm 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 20 N/15 mm or less, the user tends to be able to open the opening OP by pinching it with their hand and applying 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 within the resealed area tends to be easily maintained. When the heat seal strengths SH2 and SH3 in region R2 are 5 N/15 mm or lower, the user tends to be able to open region R2 within the resealed area with light force.

The difference between the heat seal strengths SH2 and SH3 and SH1, SH4 to SH6 may be, for example, 5 N/15 mm or more, 10 N/15 mm or more, or 15 N/15 mm or more. Note that the heat seal strengths SH2 and SH3 may decrease with repeated opening and resealing of the opening OP 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 (0.5 N/15 mm to 20 N/15 mm). The heat seal strengths SH2 and SH3 at the first opening of the packaging bag 1 may be, for example, 3 N/15 mm to 20 N/15 mm. The heat seal strengths SH2 and SH3 at resealing may be, for example, 0.5 N/15 mm to 10 N/15 mm.

[Method for forming a resealed portion]
Next, an example of a method for forming the resealable portion described above on the packaging bag 1 will be explained with reference to Figure 4.

The heat-sealing unit 100 of the bag-making machine illustrated in Figure 4 includes a pair of dispensing units (not shown), a heating unit 110, and a cooling unit 120. The pair of dispensing units are configured to continuously or intermittently dispensing the overlapping front-side packaging film 11 and back-side packaging film 12 in a predetermined conveying direction (see arrow Ar3 in Figure 4). The pair of dispensing units are arranged such that the heating unit 110 and the cooling unit 120 are positioned between them in the conveying direction of the films 11 and 12.

The heating unit 110 includes a pair of sealing bars 111 and a pair of sealing bars 112. The pair of sealing bars 111 are positioned above and below the films 11 and 12 so that the films 11 and 12 are located between them. The pair of sealing bars 112 are also positioned above and below the films 11 and 12 so that the overlapping films 11 and 12 are located between them. The sealing bars 112 are located downstream of the sealing bars 111 in the direction of film 11 and 12 transport.

The sealing bars 111 and 112 are rod-shaped members extending along the conveying direction of the films 11 and 12. At least one of the pair of sealing bars 111 is configured to be heated by a heating source (not shown), such as a heater. At least one of the pair of sealing bars 111 is configured to move closer to or further away from the other by a drive source (not shown). At least one of the pair of sealing bars 112 is configured to be heated by a heating source (not shown), such as a heater. At least one of the pair of sealing bars 112 is configured to move closer to or further away from the other by a drive source (not shown). In the example in Figure 4, the temperatures of sealing bar 111 and sealing bar 112 may be set to approximately the same temperature.

The cooling unit 120 is located downstream of the heating unit 110 in the conveying direction. The cooling unit 120 consists of a pair of cooling bars. The pair of cooling bars are positioned above and below the films 11 and 12, with the films 11 and 12 positioned between them. The pair of cooling bars are rod-shaped members extending along the conveying direction of the films 11 and 12. At least one of the pair of cooling bars is configured to move closer to or further away from the other by a drive source (not shown).

In the example shown in Figure 4, when a predetermined region of the films 11 and 12 reaches the pair of sealing bars 111, the delivery unit stops operating. In this state, the pair of sealing bars 111 move close to each other and sandwich the films 11 and 12, causing the polyolefin layer 23 and the sealant layer 12a to be heat-fused. As a result, only the region R3 corresponding to region R1 of the joining region R of the films 11 and 12 is heat-fused. Subsequently, the pair of sealing bars 111 separate from each other, and the delivery unit feeds the films 11 and 12 downstream in the transport direction.

When the region R3 formed by the seal bar 111 reaches the pair of seal bars 112, the delivery unit stops operating. In this state, the pair of seal bars 112 move close to each other and sandwich the films 11 and 12, causing the polyolefin layer 23 and the sealant layer 12a to be heat-sealed again. As a result, the region of the films 11 and 12 corresponding to the joining region R is heat-sealed. That is, because region R3 is heat-sealed multiple times by the seal bars 111 and 112, region R3 becomes region R1 of the joining region R. On the other hand, the region of the films 11 and 12 that is heat-sealed only by the seal bar 112 becomes region R2 of the joining region R. As a result, the heat seal strengths SH2 and SH3 in region R1, which is heat-sealed twice, are greater than the heat seal strengths SH2 and SH3 in region R2, which is heat-sealed only once. After that, the pair of seal bars 112 move apart from each other, and the delivery unit sends the films 11 and 12 downstream in the transport direction.

When the bonding region R formed by the sealing bar 112 reaches the pair of cooling bars, the dispensing unit stops operating. In this state, the pair of cooling bars move close to each other and sandwich the films 11 and 12, thereby cooling the bonding region R. In this way, a resealed portion is formed on the packaging bag 1.

Furthermore, in the example of the heat-sealing unit 100 in Figure 4, the seal bar 112 may be located upstream of the seal bar 111. Also, the heat-sealing unit 100 in Figure 4 may include sets of three or more seal bars. In this case, a bonding region R may be formed that includes multiple regions where the heat seal strengths SH2 and SH3 decrease as you move towards the inlet OP side.

The bonding region R formed on films 11 and 12 may be clamped once or multiple times by each bar of the sealing bars 111 and 112 of the heating unit 110 and the cooling bar of the cooling unit 120. For example, when forming the bonding region R on films 11 and 12, the films 11 and 12 may be intermittently moved by the feeding unit, while each bar clamps the region that will become the bonding region R one or more times.

[Effect]
As shown in the above example, when opening the resealed portion, the region R2 with relatively low heat seal strengths SH2 and SH3 is opened first, followed by the region R1 with relatively high heat seal strengths SH2 and SH3. In other words, a user attempting to open the packaging bag 1 will first apply a relatively small force to the resealed portion, followed by a larger force. Therefore, compared to the case where the resealed portion is composed only of the region R1 with relatively high heat seal strengths SH2 and SH3, the user does not need to suddenly apply a large force to the resealed portion. Consequently, the user can easily open the resealed portion. Furthermore, since it is less likely for a large force to be suddenly applied to the resealed portion, the heat seal strengths SH2 and SH3 of the resealed portion tend to stabilize. Therefore, it is possible to maintain good strength in the resealed portion when resealing the packaging bag 1.

As shown in the above example, the exposed adhesive layer 22 adheres to the mating surface (polyolefin layer 23), thereby resealing the opening OP. Since the resealing portion extends along the left-right direction Ar2 from the left side 1L to the right side 1R near the opening OP, virtually no gap is created in the opening OP when it is resealed by the exposed adhesive layer 22. Therefore, in a so-called three-side seal bag (a bag formed by bonding the bottom and sides of two films together), it is possible to improve the preservation of the contents during resealing. Alternatively, although not shown in the figures, by applying the technology of this disclosure to a so-called standing pouch (a bag that can stand on its own because its bottom expands when contents are placed inside), it is possible to improve the preservation of the contents during resealing even in a standing pouch. Note that the standing pouch may further include a bottom packaging film that joins the front packaging film 11 and the back packaging film 12 at their bottoms 1B, as described above in the packaging bag 1.

In the above example, the resealable film 20 is provided on the outer packaging film 11 so as to cover the entire inner surface of the outer packaging film 11. Therefore, the resealable film 20 can be formed on the entire inner surface of the outer packaging film 11 in the same process as forming the outer packaging film 11. In a configuration where the resealable film 20 is formed on only a portion of the outer packaging film 11, it is necessary to prepare the resealable film 20 and the outer packaging film 11 separately and then bond them together. However, in the above example, such a bonding process is unnecessary, making it possible to efficiently manufacture a resealable packaging bag 1.

In the above example, the resealable film 20 is formed on the inner surface of the outer packaging film 11, and the resealable film 20 has a three-layer structure (polyolefin layer 21, adhesive layer 22, and polyolefin layer 23). Therefore, while simplifying the structure of the resealable film 20, functions such as barrier properties, pinhole resistance, and aesthetic appeal can be imparted to the outer packaging film 11. Thus, by combining an outer packaging film 11 whose material is selected according to the specific contents with a resealable film 20 with a simple structure, it becomes possible to provide a variety of packaging bags 1 that can accommodate various contents.

[Variations]
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.

(1) When forming the resealable portion on the packaging bag 1, the heat-sealing unit 100 of the bag-making machine illustrated in Figure 5 may be used. This heat-sealing unit 100 differs from the heat-sealing unit 100 illustrated in Figure 4 in that it includes a seal bar 111 that heat-seals only the region R1 of the joining region R of the films 11 and 12, and a seal bar 112 that heat-seals only the region R2 of the joining region R of the films 11 and 12.

In the example shown in Figure 5, the temperature of the sealing bar 111 is set to be higher than that of the sealing bar 112. Therefore, the heat seal strengths SH2 and SH3 in the region clamped by the sealing bar 111 are greater than the heat seal strengths SH2 and SH3 in the region clamped by the sealing bar 112. That is, the region clamped by the sealing bar 111 becomes region R1 of the bonding region R, and the region clamped by the sealing bar 112 becomes region R2 of the bonding region R.

Furthermore, in the example of the heat-sealing unit 100 in Figure 5, the seal bar 112 may be located upstream of the seal bar 111. Also, the heat-sealing unit 100 in Figure 5 may include sets of three or more seal bars, each set to a different temperature. In this case, a bonding region R may be formed that includes multiple regions where the heat seal strengths SH2 and SH3 decrease as you move towards the inlet OP.

(2) As illustrated in Figure 6, the sealing bar of the heating unit 110 and the cooling bar of the cooling unit 120 may be arranged to intersect along the transport direction of the films 11 and 12. In this case as well, as illustrated in Figure 6(a), similar to the example in Figure 4, the region of the films 11 and 12 corresponding only to region R1 of the joining region R may be heat-sealed by the sealing bar 111, while the region of the films 11 and 12 corresponding to the joining region R may be heat-sealed by the sealing bar 112.

As illustrated in Figure 6(b), similar to the example in Figure 5, the region of films 11 and 12 corresponding only to region R1 of the joining region R may be heat-sealed by the sealing bar 111, while the region of films 11 and 12 corresponding only to region R2 of the joining region R may be heat-sealed by the sealing bar 112. In this case as well, the temperature of the sealing bar 111 is set to be higher than the temperature of the sealing bar 112.

(3) Although not shown in the figures, when the packaging bag 1 is opened, the adhesive layer 22 and the polyolefin layer 23 may rupture near the edge X1 on the entrance OP side of the bonding region R. In this case, the adhesive layer 22 may peel off from the polyolefin layer 21 (so-called interlayer delamination), and the adhesive layer 22 may be exposed from the polyolefin layer 21. Furthermore, the adhesive layer 22 and the polyolefin layer 23 may rupture near the edge X2 on the side of the bonding region R opposite to the entrance OP (the side facing the internal space of the packaging bag 1).

(4) As illustrated in Figure 7, the adhesive layer 22 may be exposed by coagulation and peeling within its own layer.

(5) The resealing film 20 may be provided in the region of the inner surface of the outer packaging film 11 that includes the bonding region R. In this case as well, the adhesive layer 22 may be exposed by peeling between the polyolefin layers 21 or 23, or by agglomeration and peeling within its own layer. As illustrated in Figure 8, the resealing film 20 may be provided only in the bonding region R on the inner surface of the outer packaging film 11. In this case, since the resealing portion is provided in the minimum necessary area, it becomes 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 outer packaging film 11, the outer packaging film 11 may further include a sealant layer 11a provided on the inner surface of the base layer or intermediate layer, as illustrated in Figure 8. The configuration of the sealant layer 11a may be the same as that of the sealant layer 12a.

(6) As illustrated in Figure 9, a resealing film 20 may also be provided on the inner surface of the back packaging film 12. In this case, the heat seal strength between the polyolefin layer 23 of the resealing film 20 provided on the inner surface of the front packaging film 11 and the polyolefin layer 21 of the resealing film 20 provided on the inner surface of the back packaging film 12 may be greater than the heat seal strengths SH2 and SH3.

(7) As illustrated in Figure 10, the bonding region R may extend non-linearly along the left-right direction Ar2 from the left side 1L to the right side 1R near the entrance portion OP. In other words, the bonding region R may include a curved portion Ra that protrudes in the vertical direction Ar1. In this case, when opening the entrance portion OP, the adhesive layer 22 of the resealing portion peels off from the top or base end of the curved portion Ra. Therefore, compared to a configuration where the bonding region R is linear, the user can open the entrance portion OP with moderate force without requiring excessive force.

In the example shown in Figure 10(a), the joining region R includes a V-shaped bend Ra that folds outwards from the opening OP towards the internal space of the packaging bag 1. In the example shown in Figure 10(b), the joining region R includes a V-shaped bend Ra that folds outwards from the internal space of the packaging bag 1 towards the opening OP. In the example shown in Figure 10(c), the joining region R includes a U-shaped bend Ra that curves outwards from the opening OP towards the internal space of the packaging bag 1. In the example shown in Figure 10(d), the joining region R includes a U-shaped bend Ra that curves outwards from the internal space of the packaging bag 1 towards the opening OP. In the example shown in Figure 10(e), the joining region R exhibits a sinusoidal wave shape. In the example shown in Figure 10(f), the joining region R exhibits a triangular wave shape. The joining region R may also exhibit other wave shapes (e.g., sawtooth wave shape).

(8) As illustrated in Figure 11, the front packaging film 11 and the back packaging film 12 may be provided with a sealing portion 34 at the upper part 1T where they are sealed to each other. In this case, the sealing portions 31 and 32 may each be provided with a tear-start portion 40. The tear-start portion 40 may be, for example, a notch. The shape of the notch may be, for example, a triangular shape, a home plate shape (unequal-sided pentagon shape), an I-shape, a rectangular shape, a semicircular shape, or various other shapes. The tear-start portion 40 may be, for example, an easy-open processing portion in which the outer surface of the front packaging film 11 or the back packaging film 12 is removed and thinned, or an easy-open processing portion in which a large number of fine holes are provided in the sealing portions 31 and 32. The outer surfaces of the front packaging film 11 and the back packaging film 12 may each be provided with a half-cut line 50 (opening guide line). The half-cut line 50 may extend to connect the tear-starting portions 40 provided in the seal portions 31 and 32, respectively. The half-cut line 50 may be linear or non-linear (e.g., V-shaped, U-shaped, wavy, etc.).

(9) As illustrated in Figures 12 and 13, the technology of this disclosure may be applied to a so-called four-sided sealed bag with a folded gusset (a bag with all four sides sealed). In this case, the packaging bag 1 may consist of a front packaging film 11, a back packaging film 12, a side packaging film 13 (first side packaging film), a side packaging film 14 (second side packaging film), and a bottom packaging film 15. The side packaging films 13 and 14 are each folded inward near the opening OP.

The front packaging film 11 and the side packaging film 13 may be provided with a column seal portion 61 (first column seal portion) sealed at the side edges where they meet. The front packaging film 11 and the side packaging film 14 may be provided with a column seal portion 62 (second column seal portion) sealed at the side edges where they meet. The back packaging film 12 and the side packaging film 13 may be provided with a column seal portion 63 (third column seal portion) sealed at the side edges where they meet. The back packaging film 12 and the side packaging film 14 may be provided with a column seal portion 64 (fourth column seal portion) sealed at the side edges where they meet. Each of the films 11 to 15 may be provided with a seal portion 65 sealed at the lower edge and peripheral edge where they meet.

The bonding region R may extend around the entire circumference of each film 11-14 near the entrance portion OP, as shown in Figures 12 and 13. The bonding region R may extend along the left-right direction Ar2 from the left side 1L to the right side 1R near the entrance portion OP along the inner surface of the front packaging film 11, and also along the left-right direction Ar2 from the left side 1L to the right side 1R near the entrance portion OP along the inner surface of the back packaging film 12. In this case, the resealing portion may include a first portion (first resealing portion) provided on the inner surface of the front packaging film 11 and a second portion (second resealing portion) provided on the inner surface of the back packaging film 12.

When opening the packaging bag 1 illustrated in Figures 12 and 13, the user grasps the front packaging film 11 and the back packaging film 12 at the opening OP and applies force to pull them apart. As a result, as illustrated in Figure 13, the adhesive layer 22 is exposed through interlayer delamination or cohesive delamination, and the front packaging film 11 and the back packaging film 12 separate at the opening OP, opening the packaging bag 1. On the other hand, when resealing the packaging bag 1 illustrated in Figures 12 and 13, as illustrated in Figure 12, the side packaging films 13 and 14 are folded inward, respectively, while pressing the front packaging film 11 and the back packaging film 12 at the opening OP against each other. As a result, the exposed adhesive layer 22 adheres to the other, and the opening OP of the packaging bag 1 is resealed in the joining region R. According to the packaging bag 1 illustrated in Figures 12 and 13, the resealing section reseals the opening OP, including the side packaging films 13 and 14 that are folded inward. Therefore, when opening the opening OP, it is possible to ensure a larger opening size for the opening OP (see Figure 13).

(10) As illustrated in Figures 14 and 15, the technology of the present disclosure may be applied to so-called gusseted bags (bags with folded gussets). In this case, the packaging bag 1 may be made of a single packaging film 10. The packaging film 10 may include a surface portion 10a that constitutes the surface of the packaging bag 1, a back portion 10b that constitutes the back surface of the packaging bag 1, a left side portion 10c (first gusset portion) that constitutes the left side of the packaging bag 1, and a right side portion 10d (second gusset portion) that constitutes the right side of the packaging bag 1. The packaging film 10 may be provided with a column seal portion 71 whose side edges are sealed together and a seal portion 72 that seals the bottom portion 1B. The column seal portion 71 may extend in the vertical direction Ar1 on the back portion 10b. The sealing portion 72 may be formed by joining the surface portion 10a, the back portion 10b, the left side portion 10c, and the right side portion 10d so as to extend in the left-right direction Ar2 at the bottom portion 1B.

The bonding region R may extend around the entire circumference of the front surface 10a, back surface 10b, left side surface 10c, and right side surface 10d in the vicinity of the entrance portion OP, as shown in Figures 14 and 15. The bonding region R may extend along the left-right direction Ar2 to the inner surface of the packaging film 10 from the left side surface 10c to the right side surface 10d in the vicinity of the entrance portion OP, and may also extend along the left-right direction Ar2 to the inner surface of the packaging film 10 from the left side surface 10c to the right side surface 10d in the vicinity of the entrance portion OP. In this case, the resealing portion may include a first portion (first resealing portion) provided on the inner surface of the front surface 10a of the packaging film 10, and a second portion (second resealing portion) provided on the inner surface of the back surface 10b of the packaging film 10.

When opening the packaging bag 1 illustrated in Figures 14 and 15, the user grasps the front surface 10a and back surface 10b at the opening OP and applies force to pull them apart. As a result, as illustrated in Figure 15, the adhesive layer 22 is exposed through interlayer delamination or cohesive delamination, and the front surface 10a and back surface 10b at the opening OP are separated, opening the packaging bag 1. On the other hand, when resealing the packaging bag 1 illustrated in Figures 14 and 15, as illustrated in Figure 14, the left side surface 10c and right side surface 10d are folded inward, and the front surface 10a and back surface 10b at the opening OP are pressed together. As a result, the exposed adhesive layer 22 adheres to the other, and the opening OP of the packaging bag 1 is resealed in the joining region R. According to the packaging bag 1 illustrated in Figures 14 and 15, the resealing portion reseals the opening portion OP, including the left side portion 10c and the right side portion 10d that are folded inward. Therefore, compared to gusseted bags with a zipper near the opening (see Patent Document 1), it is possible to ensure a larger opening size for the opening portion OP when opening the opening portion OP (see Figure 15).

[Other examples]
Example 1. An example of a packaging bag is a resealable packaging bag constructed by joining one or more packaging films to form a bag shape, and including a front portion and a back portion that are overlapped and facing each other. The example of a packaging bag includes a pair of first and second sides, a bottom connecting the first and second sides, an entrance located on the opposite side of the bottom, and a resealable joint area extending along a first direction from the first side to the second side near the entrance, where the first and second sides are aligned. The resealable joint area includes a first portion sandwiched between the front portion and the back portion in the joint area when the entrance is sealed, and a second portion located in the joint area closer to the entrance than the first portion and adjacent to the first portion. The heat seal strength of the first portion is greater than the heat seal strength of the second portion. In this case, when opening the resealed portion, the second portion with relatively low heat seal strength is opened first, followed by the first portion with relatively high heat seal strength. That is, the user attempting to open the packaging bag applies a relatively small force to the resealed portion first, and then a larger force. Therefore, compared to the case where the resealed portion is composed only of the second portion with relatively high heat seal strength, the user does not need to suddenly apply a large force to the resealed portion. Consequently, the user can easily open the resealed portion. Also, since it is less likely for a large force to be suddenly applied to the resealed portion, the peeling of the resealed portion becomes more stable. Therefore, it is possible to maintain good strength in the resealed portion when resealing the packaging bag.

Example 2. In the packaging bag of Example 1, the heat seal strength of the first portion may be 5 N/15 mm or more and 20 N/15 mm or less, and the heat seal strength of the second portion may be 0.5 N/15 mm or more and less than 5 N/15 mm. When the heat seal strength of the first portion is 5 N/15 mm or more, unintended leakage of the contents of the packaging bag tends to be prevented. When the heat seal strength of the first portion is 20 N/15 mm or less, users tend to be able to open the opening with moderate force by pinching the opening with their fingers. When the heat seal strength of the second portion is 0.5 N/15 mm or more, the sealed state of the first portion tends to be easily maintained. When the heat seal strength of the second portion is 5 N/15 mm or less, users tend to be able to open the second portion with light force.

Example 3. In the packaging bag of Example 1 or Example 2, one or more packaging films include a front packaging film corresponding to the front surface and a back packaging film corresponding to the back surface. The front and back packaging films are provided with a first seal portion sealed at the first side and a second seal portion sealed at the second side. The resealing portion may extend along the first direction from the first seal portion to the second seal portion near the opening. In this case, it becomes possible to improve the preservation of the contents during resealing in so-called three-side seal bags (bags made by bonding the bottom and sides of two films) and so-called standing pouches (bags that can stand on their own when the bottom expands when contents are stored inside).

Example 4. In the packaging bag of Example 1 or Example 2, one or more packaging films include a front packaging film corresponding to the front surface, a back packaging film corresponding to the back surface, a first side packaging film corresponding to the first side and folded inward near the opening, and a second side packaging film corresponding to the second side and folded inward near the opening, wherein the front packaging film and the first side packaging film are provided with a first column seal portion sealed at the side edges where they meet, and the front packaging film and the second side packaging film are provided with a second column seal portion sealed at the side edges where they meet, and the back packaging film The front packaging film and the first side packaging film are provided with a third column seal portion sealed at the side edges where they meet, and the back packaging film and the second side packaging film are provided with a fourth column seal portion sealed at the side edges where they meet. The resealing portion may include a first resealing portion provided on the inner surface of the front packaging film so as to extend along a first direction from the first column seal portion to the second column seal portion near the entrance, and a second resealing portion provided on the inner surface of the back packaging film so as to extend along a first direction from the third column seal portion to the fourth column seal portion near the entrance. In this case, it is possible to improve the preservation of the contents when resealing a so-called four-sided column seal bag with a folded gusset (a bag with all four sides sealed). Furthermore, since the resealing section includes a first resealing section extending along the first direction from the first column seal section to the second column seal section near the entrance, and a second resealing section extending along the first direction from the third column seal section to the fourth column seal section near the entrance, the resealing section reseals the entrance section, including each side packaging film folded inward. Therefore, when opening the entrance section, it is possible to ensure a larger opening size.

Example 5. In the packaging bag of Example 1 or Example 2, one or more packaging films include one packaging film formed in a tubular shape, and one packaging film includes a front portion, a back portion, a first gusset portion corresponding to a first side portion and extending integrally to connect the front portion and the back portion, with the vicinity of the opening portion folded inward, and a second gusset portion corresponding to a second side portion and extending integrally to connect the front portion and the back portion, with the vicinity of the opening portion folded inward, and one packaging film is provided with column seal portions where the side edges of one packaging film are sealed together, and the reseal portion may include a first reseal portion provided on the inner surface of the front portion so as to extend along a first direction from the first gusset portion to the second gusset portion near the opening portion, and a second reseal portion provided on the inner surface of the back portion so as to extend along a first direction from the first gusset portion to the second gusset portion near the opening portion. In this case, it becomes possible to improve the preservation of the contents when resealing a so-called gusseted bag (a bag with folded gussets). Furthermore, since the resealing section includes a first resealing section extending along the first direction from the first gusset to the second gusset near the opening, and a second resealing section extending along the first direction from the third gusset to the fourth gusset near the opening, the resealing section reseals the opening, including each side packaging film folded inward. Therefore, it becomes possible to ensure a larger opening when opening the opening.

Example 6. In any of the packaging bags of Examples 1 to 5, the resealable portion may include a first polyolefin layer, an adhesive layer laminated on the first polyolefin layer, and a second polyolefin layer laminated on the adhesive layer.

Example 7. In the packaging bag of Example 6, the heat seal strength of the adhesive layer at the resealing portion may be lower than the heat seal strength of the layers other than the adhesive layer at the resealing portion. In this case, when opening the opening, the adhesive layer at the resealing portion is more likely to peel off first. Therefore, it becomes possible to open the opening more reliably.

Example 8. In the packaging bag of Example 7, the heat seal strength of the adhesive layer at the resealing portion may be 0.5 N/15 mm to 20 N/15 mm. When the heat seal strength of the adhesive layer at the resealing portion is 0.5 N/15 mm or higher, the adhesion between the adhesive layer and the first or second polyolefin layer tends to be easily maintained. When the heat seal strength of the adhesive layer at the resealing portion is 20 N/15 mm or lower, the user tends to be able to open the opening with moderate force by pinching the opening with their fingers.

Example 9. In any of the packaging bags of Examples 6 to 8, the adhesive layer may be configured to peel off and be exposed between the first polyolefin layer and the second polyolefin layer when the opening is made.

Example 10. In any of the packaging bags from Examples 6 to 8, the adhesive layer may be configured to aggregate and peel off within its own layer and be exposed when the opening at the entrance is opened.

Example 11. In any of the packaging bags from Examples 1 to 10, the resealing portion may be located only within the joining area. In this case, since the resealing portion is provided in the minimum necessary area, it becomes possible to manufacture resealable packaging bags at a low cost.

Example 12. In any of the packaging bags from Examples 1 to 10, the resealable portion may be provided on the surface so as to cover the entire inner surface of the surface. In this case, since the resealable portion can be formed on the entire inner surface of the surface in the same process as forming the surface, it becomes possible to efficiently manufacture resealable packaging bags.

Example 13. In any of the packaging bags of Examples 1 to 12, the joining region may include a curved portion that protrudes in a second direction where the opening and bottom portions are aligned. In this case, when the opening is opened, the adhesive layer of the resealing portion peels off from the top or base of the curved portion. Therefore, compared to a configuration where the joining region is straight, the user can open the opening with moderate force without requiring excessive force.

Example 14. In the packaging bag of Example 13, the joining region may have a V-shape, a U-shape, or a wave-like shape.

1…Packaging bag, 1L…Left side (first side), 1R…Right side (second side), 1B…Bottom, 10…Packaging film, 10a…Front side, 10b…Back side, 10c…Left side (first gusset), 10d…Right side (second gusset), 11…Front packaging film (front side), 12…Back packaging film (back side), 13…Side packaging film (first side packaging film), 14…Side packaging film (second side packaging film), 20…Resealing film (resealing part), 21…Polyolefin layer (first polyolefin layer) ), 22...Adhesive layer, 23...Polyolefin layer (second polyolefin layer), 31...Sealing section (first sealing section), 32...Sealing section (second sealing section), 61...Column sealing section (first column sealing section), 62...Column sealing section (second column sealing section), 63...Column sealing section (third column sealing section), 64...Column sealing section (fourth column sealing section), Ar1...Vertical direction (second direction), Ar2...Left-right direction (first direction), OP...Entrance section, R...Jointing area, R1...Area (first part), R2...Area (second part), Ra...Bend section.

Claims (14)

A resealable packaging bag is constructed by joining one or more packaging films together to form a bag, and includes a front portion and a back portion that are overlapped and facing each other,
A pair of first and second side portions,
A bottom portion connecting the first side portion and the second side portion,
An entrance located on the opposite side of the bottom,
The device includes a resealable portion configured to reseal a joint region extending along a first direction in which the first side portion and the second side portion are aligned, from the first side portion to the second side portion in the vicinity of the entrance portion,
The resealing portion is
With the entrance portion sealed, the joint region is sandwiched between the surface portion and the back portion.
The first portion arranged in the joining region,
The joining region includes a second portion which is located closer to the entrance than the first portion and adjacent to the first portion,
A packaging bag in which the heat seal strength of the first portion is greater than the heat seal strength of the second portion. The heat seal strength of the first portion is 5 N/15 mm or more and 20 N/15 mm or less.
The packaging bag according to claim 1, wherein the heat seal strength of the second portion is 0.5 N/15 mm or more and less than 5 N/15 mm. The aforementioned single or more packaging films are
A front packaging film corresponding to the aforementioned surface portion,
Includes a back packaging film corresponding to the back surface,
The front packaging film and the back packaging film include:
The first sealing portion sealed on the first side,
A second sealing portion is provided on the second side,
The packaging bag according to claim 1 or 2, wherein the resealing portion extends along the first direction from the first sealing portion to the second sealing portion near the entrance portion. The aforementioned single or more packaging films are
A front packaging film corresponding to the aforementioned surface portion,
A back packaging film corresponding to the back surface,
A first side packaging film corresponding to the first side portion and with the vicinity of the entrance portion folded inward,
It includes a second side packaging film corresponding to the second side portion and having the vicinity of the entrance portion folded inward,
The front packaging film and the first side packaging film are provided with a first column seal portion that is sealed at the side edges where they meet.
The front packaging film and the second side packaging film are provided with a second column seal portion that is sealed at the side edge where they meet.
The aforementioned back packaging film and the aforementioned first side packaging film are provided with a third column sealing portion sealed at the side edge where they meet.
The aforementioned back packaging film and the aforementioned second side packaging film are provided with a fourth column sealing portion sealed at the side edge where they meet.
The resealing portion is
A first resealing portion is provided on the inner surface of the outer packaging film so as to extend along the first direction from the first column sealing portion to the second column sealing portion near the entrance portion,
The packaging bag according to claim 1 or 2, further comprising a second resealing portion provided on the inner surface of the back packaging film so as to extend along the first direction from the third column sealing portion to the fourth column sealing portion near the entrance portion. The aforementioned single or more packaging films include a single packaging film formed in a tubular shape.
The aforementioned single packaging film is
The aforementioned surface portion and,
The aforementioned back surface and,
A first gusset portion, corresponding to the first side portion, extending integrally to connect the front portion and the back portion, and having the vicinity of the entrance portion folded inward,
It includes a second gusset portion that corresponds to the second side portion, extends integrally to connect the front portion and the back portion, and has the vicinity of the opening portion folded inward,
The aforementioned single packaging film is provided with a columnar sealing portion where the side edges of the single packaging film are sealed together.
The resealing portion is
A first resealing portion is provided on the inner surface of the surface portion so as to extend along the first direction from the first gusset portion to the second gusset portion in the vicinity of the entrance portion,
The packaging bag according to claim 1 or 2, further comprising a second resealing portion provided on the inner surface of the back portion so as to extend along the first direction from the first gusset portion to the second gusset portion in the vicinity of the opening portion. The resealing portion is
A first polyolefin layer,
The adhesive layer laminated on the first polyolefin layer,
A packaging bag according to any one of claims 1 to 5, comprising a second polyolefin layer laminated on the adhesive layer. The packaging bag according to claim 6, wherein the heat seal strength of the adhesive layer in the resealing portion is less than the heat seal strength of the layers other than the adhesive layer in the resealing portion. The packaging bag according to claim 7, wherein the heat seal strength of the adhesive layer in the resealable portion is 0.5 N/15 mm to 20 N/15 mm. The packaging bag according to any one of claims 6 to 8, wherein the adhesive layer is configured to peel off and be exposed between the first polyolefin layer and the second polyolefin layer when the inlet is opened. The packaging bag according to any one of claims 6 to 8, wherein the adhesive layer is configured to aggregate and peel off within its own layer and be exposed when the inlet is opened. The packaging bag according to any one of claims 1 to 10, wherein the resealing portion is located only within the joining region. The packaging bag according to any one of claims 1 to 10, wherein the resealing portion is provided on the surface portion so as to cover the entire inner surface of the surface portion. The packaging bag according to any one of claims 1 to 12, wherein the joining region includes a curved portion that curves so as to protrude in a second direction in which the entrance portion and the bottom portion are aligned. The packaging bag according to claim 13, wherein the joining region exhibits a V-shape, U-shape, or wave-like shape.