Packaging bag

Abstract

To provide a packaging bag which can maintain high reseal strength even after repeated opening and resealing while improving initial ease of opening.SOLUTION: A packaging bag 100 is configured by joining one or more packaging films together to form a bag type having a storage part 102, and includes: a first side part 1L and a second side part 1R which are a pair of side parts; a bottom part 1B connecting the first side part 1L and the second side part 1R; an entrance part OP located on the opposite side to the bottom part 1B; and a belt-like resealable part R that is resealably sealed so as to traverse between the first side part 1L and the second side part 1R, a boundary line K between the resealable part R and a non-sealed part on an entrance part OP side of the resealable part R is recessed toward the storage part 102 in a central part, the width of the resealing part R is narrower in the center part than near the side part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a packaging pouch. [Background technology]

[0002] There are known packaging bags that can be repeatedly opened and sealed in order to maintain the state of the contents contained therein, etc. For example, Patent Document 1 discloses a resealable packaging bag that has an adhesive film on the opening part in order to improve the preservation of the contents. Patent Document 2 discloses a packaging bag in which the resealable part can be easily opened by making the seal strength different between the top and bottom of the resealable part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-090613 [Patent Document 2] Patent Publication No. 2022-090620 Summary of the Invention [Problem to be solved by the invention]

[0004] In a resealable packaging bag, the ease of opening a sealed resealable portion improves as the seal strength of the sealed portion decreases. On the other hand, the reseal strength of such a packaging bag after it has been opened once decreases with each repeated opening and resealing, and there is a concern that the resealable portion may not be sufficiently sealed. Thus, there is a trade-off between the initial ease of opening the resealable portion and the sealability after opening. The present disclosure provides a packaging bag that can maintain high reseal strength even after repeated opening and resealing while improving the initial ease of opening. [Means for solving the problem]

[0005] One aspect of the present disclosure provides a packaging bag comprising one or more packaging films joined together to form a bag having a storage portion, the packaging bag comprising a pair of sides, a first side and a second side, a bottom connecting the first side and the second side, an entrance portion located opposite the bottom, and a strip-shaped resealable portion that is resealably sealed so as to traverse between the first side and the second side, wherein the boundary line between the resealable portion and an unsealed portion on the entrance side of the resealable portion is recessed in the central portion toward the storage portion, and the width of the resealable portion is narrower in the central portion than in the portions near the sides.

[0006] In the above packaging bag, the boundary between the sealed portion and the non-sealed portion in the resealing portion on the entrance side is recessed toward the storage portion in the center. Since the resealing portion has a recess in this manner, the force of pulling apart when opening the resealing portion acts effectively on the boundary forming the recess, so that peeling of the sealed portion proceeds smoothly and the initial opening strength can be reduced. This also allows the sealed portion of the resealing portion to be peeled off smoothly, and the adhesive surface of the resealing portion can be neatly exposed. Therefore, the adhesive surface effective for re-adhesion when resealing is widened, and the resealing strength can be maintained high even if opening and resealing are repeated. In addition, the appearance of the resealing portion after opening can be improved. Effect of the Invention

[0007] The present disclosure can provide a packaging bag that is easy to open initially while maintaining high reseal strength even after repeated opening and resealing. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a plan view showing an example of a packaging bag. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 4 is an enlarged view of the resealable portion of the packaging bag. [Figure 4] FIG. 2 is a perspective view showing an example of a processed seal bar. [Diagram 5] 5(a) to 5(d) are diagrams showing modified examples of the resealing portion. [Figure 6] FIG. 11 is a plan view showing another example of a packaging bag. [Figure 7] 1 is a photograph of the exposed adhesive layer in the test film of Example 8. [Figure 8] 1 is a photograph of the exposed adhesive layer in the test film of Example 9. [Figure 9] 1 is a photograph of the exposed adhesive layer in the test film of Example 10. [Figure 10] 1 is a photograph of the exposed adhesive layer in the test film of Example 11. [Figure 11] 1 is a photograph of the exposed adhesive layer in the test film of Comparative Example 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described. However, the following embodiment is an example for explaining the present disclosure, and is not intended to limit the present disclosure to the following contents. The upper or lower limit of the numerical range specified in this disclosure may be replaced with any value shown in the examples. In addition, the upper and lower limits described individually may be arbitrarily combined. Unless otherwise specified, the materials or components exemplified in this disclosure may be used alone or in combination of two or more types. In the description, the same elements or elements having the same functions are given the same reference numerals, and duplicated descriptions are omitted. In addition, the positional relationships such as up, down, left, and right used in the description are based on the positional relationships shown in the drawings, unless otherwise specified.

[0010] Fig. 1 is a plan view showing an example of a packaging bag. The packaging bag 100 is composed of multiple packaging films. In Fig. 1, the packaging bag 100 is overlapped so that a front packaging film 11 (front surface) and a back packaging film 12 (back surface) face each other. The packaging bag 100 may have, for example, a rectangular shape as a whole.

[0011] The packaging bag 100 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 vertical direction Ar1 at the left edge of the packaging bag 100. The right side portion 1R extends along the vertical direction at the right edge of the packaging bag 100. The left side portion 1L and the right side portion 1R face each other in a horizontal direction Ar2 perpendicular to the vertical direction Ar1. The bottom portion 1B extends along the horizontal direction Ar2 at the lower edge of the packaging bag 100 so as to connect 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 horizontal direction Ar2 at the upper edge of the packaging bag 100 so as to connect 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.

[0012] 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 (for example, heat-sealed) to each other at the left side portion 1L, the right side portion 1R, and the bottom portion 1B. That is, the front packaging film 11 and the back packaging film 12 are provided with a sealed portion 31 where they are sealed to each other at the left side portion 1L, a sealed portion 32 where they are sealed to each other at the right side portion 1R, and a sealed portion 33 where they are sealed to each other at the bottom portion 1B. In addition, a storage portion 102 is provided in a portion surrounded by the sealed portions 31, 32, and 33.

[0013] From the viewpoint of ensuring a sufficient volume for putting contents inside, the volume of the storage section 102 may be 1 to 500 mL, 5 to 200 mL, 10 to 100 mL, or 15 to 50 mL.

[0014] The front packaging film 11 may be configured by laminating a base layer and an intermediate layer in this order from the outside to the inside of the packaging bag 100.

[0015] The substrate layer may be, for example, a plastic film, paper, nonwoven fabric, or the like, or may be a combination of two or more of these. The plastic film may be, for example, a polyester film, a polypropylene (PP) film, a polystyrene film, a nylon film, a polycarbonate film, a polyethylene terephthalate (PET) film, a polyacrylonitrile film, a polyimide film, or the like. As long as the plastic film exhibits a predetermined mechanical strength and dimensional stability, its material, quality, manufacturing method, and the like are not particularly limited. For example, the plastic film may be a biaxially stretched film. A vapor deposition layer of a metal such as aluminum may be formed on the surface of the plastic film. The paper may be, for example, fine paper, one-sided art paper, coated paper, cast coated paper, imitation paper, or the like. The paper used for the substrate layer may be appropriately selected based on the mechanical strength and bag-making suitability of the paper.

[0016] The intermediate layer may be arranged, for example, for the purpose of improving various physical properties of the front packaging film 11. Examples of the various physical properties include rigidity, drop strength, puncture strength, gas (e.g., water vapor, oxygen gas, etc.) barrier properties, and cosmetic properties. When rigidity, drop strength, puncture strength, etc. are to be improved, the intermediate layer may be made of, for example, a nylon film, a polyester film, etc. When the barrier properties against water vapor are to be improved, the intermediate layer may be made of, for example, an aluminum foil or other metal foil, a plastic film (e.g., a polyester film) on which a metal such as aluminum is vapor-deposited, or a plastic film (e.g., a polyester film) on which an inorganic oxide is vapor-deposited. 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. Among these, silicon oxide, aluminum oxide, magnesium oxide, etc. may be selected as the inorganic oxide in consideration of productivity and cost. When cosmetic properties are to be improved, the intermediate layer may be made of, for example, a polyester film having an aluminum vapor-deposited layer.

[0017] The base layer and the intermediate layer may be bonded by an adhesive. The adhesive may be, for example, a dry lamination adhesive. The type of adhesive may be, for example, a two-component curing urethane adhesive, a polyester urethane adhesive, a polyether urethane adhesive, an acrylic adhesive, a polyester adhesive, a polyamide adhesive, or an epoxy adhesive. When a dry lamination adhesive is used as the adhesive, the two layers may be bonded together by a dry lamination method. The front packaging film 11 may be composed of three or more layers.

[0018] The back packaging film 12 may be configured by laminating a base material layer and an intermediate layer in this order from the outside to the inside of the packaging bag 100, similarly to the front packaging film 11. The base material layer and intermediate layer of the back packaging film 12 may be the same as those described for the front packaging film 11 above.

[0019] The front packaging film 11 and the back packaging film 12 may not be sealed at the upper portion 1T. Alternatively, as described later, the front packaging film 11 and the back packaging film 12 may be sealed at the upper portion 1T (see FIG. 6). The upper portion 1T of the packaging bag 100 is provided with an entrance portion OP that communicates between the inside and the outside of the packaging bag 100 when the packaging bag 100 is opened. That is, the entrance portion OP is located on the opposite side to the bottom portion 1B of the packaging bag 100, and functions as an opening for removing the contents of the packaging bag 100 from the storage portion 102 when the packaging bag 100 is opened. The entrance portion OP also functions as an entrance for storing the contents in the storage portion 102.

[0020] Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. As shown in Fig. 2, the front packaging film 11 and the back packaging film 12 have a resealable film 20 on the inside. In the packaging bag 100 illustrated in Fig. 1 and Fig. 2, the resealable film 20 is provided on the entire inner surfaces of the front packaging film 11 and the back packaging film 12. The resealable film 20 may be provided only partially in the front packaging film 11 and the back packaging film 12.

[0021] The resealable film 20 is configured by laminating a first sealant layer 21, an adhesive layer 22, and a second sealant layer 23 in this order from the outside to the inside of the packaging bag 100. That is, the first sealant layer 21 is laminated on the front packaging film 11 and the back packaging film 12. The adhesive layer 22 is laminated on the first sealant layer 21. The second sealant layer 23 is laminated on the adhesive layer 22. The first sealant layer 21, the adhesive layer 22, and the second sealant layer 23 may be laminated by lamination. The lamination method may be any of various known methods (e.g., dry lamination, extrusion lamination). The resealable film 20 may also be a commercially available resealable film.

[0022] When the resealable film 20 is laminated to the front packaging film 11 or the back packaging film 12, the first sealant layer 21 may be laminated to the front packaging film 11 or the back packaging film 12, and then the adhesive layer 22 and the second sealant layer 23 may be laminated thereto. Alternatively, a commercially available or previously prepared resealable film 20 may be directly laminated to the front packaging film 11 or the back packaging film 12.

[0023] The first sealant layer 21 may be configured to melt by heat and fuse to another sheet. That is, the first sealant layer 21 may be configured to be heat-sealable. The first sealant layer 21 may be configured, for example, of a polyolefin resin. The polyolefin resin may be, for example, 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, polypropylene, or the like. When the above-mentioned resin is used as the material of the first sealant layer 21, the first sealant layer 21 may be configured by forming the above-mentioned resin into a film shape by an extruder. The first sealant layer 21 may be a single layer or a multilayer.

[0024] The second sealant layer 23 can be made of the same material as the above-mentioned first sealant layer 21. The materials of the first sealant layer 21 and the second sealant layer 23 may be the same as or different from each other.

[0025] A modified example of the packaging bag 100 may be configured such that, unlike that shown in Figure 2, one of the front packaging film 11 and the back packaging film 12 has a resealable film 20, and the other has only the first sealant layer 21 or the second sealant layer 23.

[0026] Another modified example of the packaging bag 100 may be configured such that the adhesive layer 22 is directly laminated to the front packaging film 11. That is, only the adhesive layer 22 may be laminated on the inside of the front packaging film 11 (or the back packaging film 12). In this case, the above-mentioned resealable film 20 may be laminated to the back packaging film 12 (or the front packaging film 11), or the adhesive layer 22 may be directly laminated and then the sealant layer 23 may be laminated.

[0027] In yet another modified example, the adhesive layer 22 may be directly laminated to the front packaging film 11 (or the back packaging film 12), and the sealant layer 23 may be further laminated thereon. That is, the adhesive layer 22 and the sealant layer 23 may be laminated in this order from the outside to the inside of the front packaging film 11 (or the back packaging film 12). In this case, the resealable film 20 may be laminated to the back packaging film 12 (or the front packaging film 11), or the adhesive layer 22 may be directly laminated thereon, and the sealant layer 23 may be further laminated thereon.

[0028] The packaging bag 100 has a strip-shaped resealable portion R that is resealably sealed so as to cross between the left side portion 1L and the right side portion 1R. The strip-shaped resealable portion R can be formed by heat-sealing the front packaging film 11 and the back packaging film 12, including the resealable film 20 described above. When opening the packaging bag 100, the front packaging film 11 and the back packaging film 12 are pulled apart from each other to open the heat-sealed resealable portion R. At this time, the second sealant layer 23 breaks at the upper end portion X1 and the lower end portion X2 of the resealable portion R shown in FIG. 2, and the adhesive layer 22 is peeled off from the second sealant layer 23, exposing the adhesive layer 22. After opening, the exposed adhesive layer 22 can be pressed against the opposing second sealant layer 23 to reseal the resealable portion R by adhesion. This allows the packaging bag 100 to be repeatedly opened and resealed. The pressure-sensitive adhesive layer 22 may be exposed by interlayer peeling between the pressure-sensitive adhesive layer 22 and the first sealant layer 21. Alternatively, a portion of the pressure-sensitive adhesive layer 22 may be cohesively peeled off to expose the pressure-sensitive adhesive layer 22.

[0029] As shown in FIG. 1, the resealable portion R is partitioned from the non-sealable portion by two boundary lines K1 and K2. The boundary line K1 between the sealed portion and the non-sealable portion on the entrance OP side is recessed toward the storage portion 102 side, and the width of the resealable portion R is narrower in the center than in the side portions. In other words, when an imaginary straight line P is drawn to connect both ends of the boundary line K1 in the left-right direction Ar2, there is a non-sealable portion N surrounded by the imaginary straight line P and the boundary line K1. By having the non-sealable portion N in the packaging bag 100, when the front packaging film 11 and the back packaging film 12 are pulled apart from each other to open the packaging bag 100, the resealable portion R that is heat-sealed starting from the non-sealable portion N can be opened. As a result, a force is applied from the recessed portion of the boundary line K1 toward the resealable portion R in the diagonal direction M, so that the resealable portion R is pulled apart along the diagonal direction M. Therefore, the force for peeling off the heat-sealed portion of the resealable portion R can be efficiently transmitted to the sealing surface. Therefore, the initial opening strength of the packaging bag 100 can be reduced, and the initial ease of opening can be improved.

[0030] In addition, by having the non-sealed portion N, the packaging bag 100 can improve the uniformity in the left-right direction of the force applied to the resealable portion R at the time of initial opening, and can suppress peeled off materials such as polyolefin of the sealant layers 21 and 23 from remaining on the adhesive layer 22. This allows the adhesive layer 22 to be cleanly exposed. Therefore, the effective adhesive area of ​​the adhesive layer 22 can be sufficiently maintained, and the reseal strength of the adhesive surface can be maintained high even when opening and resealing are repeated. Furthermore, the appearance of the resealable portion R after opening can be improved.

[0031] The boundary line K2 extends in a straight line, which allows the reseal strength of the adhesive surface to be maintained sufficiently high when the resealable portion is repeatedly opened and resealed.

[0032] As shown in FIG. 3, in the non-sealed portion N, the length (width W) of the virtual straight line P at the portion where the virtual straight line P and the boundary line K1 deviate from each other may be 10 to 40 mm, 15 to 35 mm, or 20 to 30 mm. By using such a non-sealed portion N, the force applied when the user holds the inlet portion OP with his / her fingers to open the package is more easily transmitted to the boundary line K1 between the non-sealed portion N and the resealed portion R, and the initial ease of opening can be further improved. In addition, the reseal strength of the adhesive surface can be maintained sufficiently high when the package is repeatedly opened and resealed. In addition, the size of the non-sealed portion N is close to the size of the user's finger, and the feeling of use when opening the package can be improved.

[0033] The maximum distance between the imaginary line P and the boundary line K1 in the direction perpendicular to the imaginary line P (height D of the non-sealed portion N) may be 2.0 to 4.0 mm, or 2.0 to 3.5 mm. Such a non-sealed portion N allows the force applied when the inlet portion OP is gripped with a finger to be more easily transmitted to the boundary line K1 between the non-sealed portion N and the resealed portion R, thereby improving initial ease of opening. In addition, the reseal strength of the adhesive surface can be maintained sufficiently high even when the opening and resealing are repeated. In addition, the size of the non-sealed portion N is closer to the size of the user's finger, improving the usability when opening.

[0034] The boundary line K1 between the non-sealed portion N and the resealable portion R has a V-shape at the center that narrows toward the storage portion 102. The V-shape can further improve the initial ease of opening of the packaging bag 100 while maintaining a higher reseal strength of the adhesive surface when opening and resealing are repeated. The apex of the V at the boundary line K1 may be pointed. From the viewpoint of further improving the initial ease of opening and maintaining a higher reseal strength of the adhesive surface when opening and resealing are repeated, the angle θ at the apex of the V may be 45 to 170°, 90 to 165°, or 120 to 160°.

[0035] The non-sealed portion N can be formed by using, for example, a seal bar 120 having a shape as shown in FIG. 4 when the front packaging film 11 and the back packaging film 12 are bonded together by heat sealing to form a strip-shaped resealed portion R. The seal bar 120 shown in FIG. 4 has a shape in which a part of a rod-shaped seal bar is cut out. The resealed portion R can be formed by using one or two seal bars 120 as shown in FIG. 4, sandwiching the front packaging film 11 and the back packaging film 12 between them and heat sealing them. On the other hand, since the cut-out portion of the seal bar 120 is not heat-sealed, a boundary line between the resealed portion R and the non-sealed portion N is formed along the cut-out portion. In FIG. 4, the cut-out portion is V-shaped, but is not limited thereto, and the cut-out portion may be U-shaped, for example. In addition, when it is V-shaped, it does not need to be a complete V-shape, and the vertices of the V-shape do not need to coincide. The shape of the cut-out portion of the seal bar 120 can be adjusted to adjust the shape of the non-sealed portion N.

[0036] 5(a) to (d) show modified examples of the resealable portion R. In FIG. 5(a), the tip is not sharp, and the non-sealable portion N1 surrounded by the imaginary straight line P and the boundary line K1 has a trapezoidal shape. In FIG. 5(b), the non-sealable portion N2 has a curved V-shaped apex at the boundary line K1. In FIG. 5(c), the line of the boundary line K1 toward the apex of the V-shape is not straight, but curved in an arc so as to be warped upward from the imaginary straight line P. In FIG. 5(d), the line of the boundary line K1 toward the apex of the V-shape is curved so that the non-sealable portion N bulges out, which is the opposite to FIG. 5(c). Even with these modified examples, the force to peel off the heat-sealed portion of the resealable portion R can be efficiently transmitted to the sealed surface, improving the initial ease of opening while maintaining high reseal strength of the adhesive surface when opening and resealing are repeated.

[0037] The heat seal strength of the resealable portion R and the reseal strength after resealing can be measured based on the "Bag heat seal strength test" defined in JIS Z 0238:1998 "Test method for heat-sealed soft packaging bags and semi-rigid containers." In the above JIS-based test method, the force required to start peeling is measured by pulling the sealed film up and down. Therefore, this measurement can measure the force required to start peeling the resealable portion R.

[0038] In the present disclosure, the heat seal strength P0 of the resealable portion R is the adhesive strength between the adhesive layer 22 and the first sealant layer 21 or the second sealant layer 23. The reseal strength Pn of the adhesive layer 22 indicates the adhesive strength of the adhesive layer 22 when resealed after being opened n times. The reseal strength can be measured for each number of resealings, with the reseal strength when opened after the first resealing being P1, the reseal strength when opened after the second resealing being P2, the reseal strength when opened after the third resealing being P3..., and the reseal strength when opened after the nth resealing being Pn.

[0039] The heat seal strength P0 of the resealable portion R may be 27.0 [N / 30 mm width] or less, 26.5 [N / 30 mm width] or less, or 26.0 [N / 30 mm width] or less. The higher the heat seal strength P0 of the adhesive layer 22, the greater the force required to open the bag, making it more difficult to open. By setting the heat seal strength P0 within the above range, the initial ease of opening the packaging bag 100 can be further improved. The heat seal strength of the adhesive layer 22 may be 15.0 [N / 30 mm width] or more from the viewpoint of improving the sealing performance of the resealable portion R.

[0040] The adhesive strength between the front packaging film 11 and the first sealant layer 21, and the heat seal strength between the second sealant layers 23 may be greater than the heat seal strength P0. This makes it easier for the adhesive layer 22 to peel off first in the resealable portion R when opening the entrance portion OP. This makes it possible to more reliably expose the adhesive layer 22 in the resealable portion R and open the package.

[0041] When the heat seal strength is P0 and the reseal strength of the pressure-sensitive adhesive layer 22 after the first resealing is P1, P1 / P0 may be 0.23 or more, 0.25 or more, or 0.27 or more. By keeping P1 / P0 within this range, the decrease in the reseal strength when opening the package after the first resealing can be sufficiently suppressed, and the reseal strength can be maintained high. P1 / P0 may be 0.80 or less.

[0042] When the heat seal strength is P0 and the reseal strength of the pressure-sensitive adhesive layer 22 after the third resealing is P3, P3 / P0 may be 0.19 or more, 0.20 or more, or 0.21 or more. When P3 / P0 is in this range, the decrease in the reseal strength when opening after three resealings is sufficiently suppressed, and the reseal strength can be maintained high. P3 / P0 may be 0.80 or less.

[0043] The effective adhesive area ratio of the adhesive layer 22 when the resealable portion R is opened may be 70% or more, 80% or more, or 90% or more. The effective adhesive area ratio indicates the ratio of the area (effective adhesive area) where the adhesive layer 22 is cleanly exposed after opening to the area of ​​the resealable portion R. The effective adhesive area of ​​the adhesive layer 22 indicates the area where no peeled material (e.g., polyolefin) originating from the sealant layers 21 and 23 is found on the adhesive layer 22 after the resealable portion R is opened. The effective adhesive area ratio can be obtained by measuring the peeled material of the sealant layers 21 and 23 remaining on the adhesive layer 22 after peeling by image analysis. By having the effective adhesive area ratio in the above range, the reseal strength can be maintained high and the appearance of the resealable portion R after opening can be improved.

[0044] FIG. 6 is a plan view showing another example of a packaging bag. As shown in FIG. 6, the packaging bag 101 may have a seal portion 34 in which the front packaging film 11 and the back packaging film 12 are sealed to each other at the upper portion 1T. In this case, the seal portions 31 and 32 may each have a tear initiation portion 40. The tear initiation portion 40 may be, for example, a notch. The shape of the notch may be, for example, a triangular shape, a home base shape (scalene pentagonal shape), an I-shape, a rectangular shape, a semicircular shape, or various other shapes. The tear initiation portion 40 may be, for example, an easy-open processed portion in which the outer surface of the front packaging film 11 or the back packaging film 12 is removed to make it thin, or may be an easy-open processed portion in which a large number of fine holes are provided in the seal portions 31 and 32. The outer surfaces of the front packaging film 11 and the back packaging film 12 may each have a half-cut line 50 (opening guide line). The half-cut line 50 may extend so as to connect the tear initiation portions 40 provided in the sealed portions 31 and 32. The half-cut line 50 may be linear or non-linear (e.g., V-shaped, U-shaped, wavy, etc.).

[0045] The configuration of packaging bag 101 other than sealed portion 34 may be the same as that of packaging bag 100. The packaging bag also has a resealable portion R that is partitioned from the non-sealed portion by boundary lines K1, K2. Therefore, while improving the initial ease of opening, it is possible to maintain high reseal strength even after repeated opening and resealing.

[0046] Although several embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-mentioned embodiments. For example, any layer or thin film may be provided between the front packaging film 11 and the first sealant layer 21 used in the above description, between the first sealant layer 21 and the adhesive layer 22, or between the adhesive layer 22 and the second sealant layer 23. The shape of the packaging bag 100 is not limited to a four-sided bag. For example, it may be a two-sided bag, a three-sided bag, or a palm-shaped bag, or it may be a standing pouch shape with a bottom packaging film added.

[0047] The present disclosure includes the following embodiments. [1] One or more packaging films are joined together to form a bag having a storage compartment; A pair of side portions, a first side portion and a second side portion; a bottom portion connecting the first side portion and the second side portion; an inlet portion located on the opposite side to the bottom; A packaging bag comprising: a strip-shaped reseal portion that is resealably sealed so as to traverse between the first side portion and the second side portion, a boundary line between the resealing portion and a non-sealing portion on the inlet side of the resealing portion is recessed toward the storage portion at a central portion, A packaging bag, wherein the width of the resealable portion is narrower in the central portion than in the portions near the sides. [2] The packaging bag according to [1], wherein when an imaginary line is drawn connecting both ends of the boundary line, the length of the imaginary line at the portion where the imaginary line deviates from the boundary line is 10 to 40 mm. [3] The packaging bag according to [1] or [2], wherein the maximum distance between the virtual line and the boundary line in a direction perpendicular to the virtual line is 2.0 to 4.0 mm. [4] The packaging bag according to any one of [1] to [3], wherein the boundary line has a V-shape in the central portion that narrows toward the storage section. [5] The resealable portion comprises an adhesive layer; A sealant layer laminated on the pressure-sensitive adhesive layer, The packaging bag according to any one of [1] to [4], wherein the pressure-sensitive adhesive layer is exposed when the entrance portion is opened. [6] The packaging bag according to [5], wherein the heat seal strength P0 of the adhesive layer in the resealable portion is 27.0 [N / 30 mm width] or less. [7] The packaging bag according to [5] or [6], wherein P1 / P0 is 0.23 or more, where P0 is the heat seal strength when the resealable portion is opened and P1 is the reseal strength of the adhesive layer after the first resealing. [8] The packaging bag according to any one of [5] to [7], wherein P3 / P0 is 0.19 or more, where P0 is the heat seal strength when the resealable portion is opened and P3 is the reseal strength of the adhesive layer after three repeated resealing operations. [9] The packaging bag according to any one of [5] to [8], wherein the effective adhesive area ratio of the adhesive layer when the resealable portion is opened is 70% or more. EXAMPLES

[0048] The present disclosure will be described in more detail below with reference to examples and comparative examples. Note that the present disclosure is not limited to the following examples.

[0049] Example 1 [Preparation of test films] A commercially available polyethylene terephthalate (PET) film (thickness 12 μm) was prepared as the base layer, a commercially available nylon (NY) film (thickness 15 μm) was prepared as the intermediate layer, and a commercially available reseal film (thickness 60 μm) was prepared as the reseal film. The PET film and the NY film were laminated by the dry lamination method, and then the reseal film was laminated on the NY film by the dry lamination method to obtain a laminated film. Two laminated films were prepared and overlapped so that the resealable films faced each other. Then, using a pair of seal bars with a width of 5 mm cut into a V-shape in the center, the two laminated films were heat-sealed using an impulse sealer so as to cross the overlapped laminated films, and a test film having a resealable portion R and a non-sealed portion N whose horizontal center portion is V-shaped as shown in FIG. 3 was prepared. The width W of the V-shaped non-sealed portion N was 20 mm, and the height D was 3 mm. The distance between the upper edge of the laminated film (the inlet portion OP in FIG. 1) and the portion of the boundary line K1 other than the non-sealed portion N was 20 mm.

[0050] [Heat seal strength measurement] The heat seal strength P0 of the prepared test film was measured based on the "Bag heat seal strength test" defined in JIS Z 0238:1998 "Test method for heat-sealed soft packaging bags and semi-rigid containers." A 15mm wide jig was used for the measurement. The V-shaped non-sealed part of the test film was placed on the jig side, and the laminated film was gripped with the jig at a position 10mm from the center of the upper edge toward the boundary line K1 (hereinafter referred to as the "chucking position"), and pulled vertically at a pulling speed of 300mm / min, and the strength applied until the start of peeling was measured. The measurement was performed on two test films.

[0051] [Reseal strength measurement] After measuring the heat seal strength, the test film was re-prepared by pressing the resealed parts with the exposed adhesive surfaces together with a constant pressure, and the reseal strength P1 after the first resealing was measured in the same manner as above. Furthermore, by repeating resealing and unsealing under the same conditions, the reseal strengths P2, P3, P4, and P5 after the second, third, fourth, and fifth resealing were measured, respectively. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were also calculated. The results are shown in Table 1.

[0052] Example 2 A test film was prepared in the same manner as in Example 1, except that the width W of the V-shaped non-sealed portion N was 30 mm and the height D was 2 mm, and the heat seal strength P0 and reseal strengths P1, P2, P3, P4, and P5 were determined. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were also calculated. The results are shown in Table 1.

[0053] Example 3 A test film was prepared in the same manner as in Example 1, except that the width W of the V-shaped non-sealed portion N was 10 mm and the height D was 2 mm, and the heat seal strength P0 and reseal strengths P1, P2, P3, P4, and P5 were determined. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were also calculated. The results are shown in Table 1.

[0054] Example 4 A test film was prepared in the same manner as in Example 1, except that the width W of the V-shaped non-sealed portion N was 20 mm and the height D was 2 mm, and the heat seal strength P0 and reseal strengths P1, P2, P3, P4, and P5 were determined. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were also calculated. The results are shown in Table 1.

[0055] Example 5 A test film was prepared in the same manner as in Example 1, except that the width W of the V-shaped non-sealed portion N was 20 mm and the height D was 4 mm, and the heat seal strength P0 and reseal strengths P1, P2, P3, P4, and P5 were determined. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were also calculated. The results are shown in Table 1.

[0056] Example 6 A test film was prepared in the same manner as in Example 1, except that the pulling speed was 100 mm / min, and the heat seal strength P0 and reseal strengths P1, P2, P3, P4, and P5 were determined. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were calculated. The results are shown in Table 1.

[0057] Example 7 The test film was prepared in the same manner as in Example 1, except that the chucking position during the measurement of the heat seal strength and reseal strength was set at a position 5 mm from the center of the upper edge of the laminated film toward the boundary line K1, and the heat seal strength P0 and the reseal strengths P1, P2, P3, P4, and P5 were determined. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were also calculated. The results are shown in Table 1.

[0058] Comparative Example 1 A test film was prepared in the same manner as in Example 1, except that no V-shaped non-sealed portion was provided, and the heat seal strength P0 and reseal strengths P1, P2, P3, P4, and P5 were determined. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were calculated. The results are shown in Table 1.

[0059] Comparative Example 2 A test film was prepared in the same manner as in Example 6, except that no V-shaped non-sealed portion was provided, and the heat seal strength P0 and reseal strengths P1, P2, P3, P4, and P5 were determined. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were calculated. The results are shown in Table 1.

[0060] Comparative Example 3 A test film was prepared in the same manner as in Example 7, except that no V-shaped non-sealed portion was provided, and the heat seal strength P0 and reseal strengths P1, P2, P3, P4, and P5 were determined. The ratios of the measured heat seal strength P0 to the reseal strengths P1, P2, P3, P4, and P5 were calculated. The results are shown in Table 1.

[0061] [Table 1]

[0062] The comparative example, which has a strip-shaped resealing portion in which the boundary between the sealed portion and the non-sealing portion is linear, had a higher heat seal strength than the examples. Therefore, it was confirmed that the initial ease of opening was improved by providing a non-sealing portion with a recessed center of the boundary. Furthermore, in each example, the resealing strength was not significantly reduced even after repeated resealing and unsealing, and the resealing strength was equivalent to that of the comparative example. Therefore, it was confirmed that the resealing strength can be maintained high even if the non-sealing portion is arranged so that the boundary between the resealing portion and the non-sealing portion is recessed in the center. Therefore, by arranging the non-sealing portion in the center of the resealing portion, it is possible to provide a packaging bag that is easy to open initially and can sufficiently maintain its airtightness after resealing.

[0063] Example 8 A test film was prepared in the same manner as in Example 1. The heat seal strength P0 of this test film was measured in the same manner as in Example 1, except that a jig with a width of 30 mm was used.

[0064] [Measurement of effective adhesive area ratio on exposed adhesive surface] After measuring the heat seal strength P0, the exposed adhesive surface was observed. A photograph of the adhesive surface is shown in FIG. 7. As shown in FIG. 7, a peeled white sealant layer Z derived from the sealant layer was attached to the adhesive surface. This peeled Z was attached by peeling off the sealant layer of the laminated film on the opposite side. The area of ​​the part where this peeled Z was attached was determined by image analysis, and the area ratio of the part where the peeled Z was not attached to the total area of ​​the adhesive surface was determined as the effective adhesive area ratio. The effective adhesive area ratio of the adhesive surface shown in FIG. 7 was 90%. Thereafter, the reseal strengths P1, P2, P3, P4, and P5 were determined in the same manner as in Example 1, except that a jig with a width of 30 mm was used. The results are shown in Table 2.

[0065] Example 9 A test film was prepared in the same manner as in Example 2. The heat seal strength P0 of this test film was measured in the same manner as in Example 8. Furthermore, the exposed effective adhesive area ratio was measured in the same manner as in Example 8. A photograph of the adhesive surface of Example 9 is shown in FIG. 8. The effective adhesive area ratio of the adhesive surface shown in FIG. 8 was 80%. Thereafter, the reseal strengths P1, P2, P3, P4, and P5 were determined in the same manner as in Example 8. The measurement results are shown in Table 2.

[0066] Example 10 A test film was prepared in the same manner as in Example 4. The heat seal strength P0 of this test film was measured in the same manner as in Example 8. Furthermore, the exposed effective adhesive area ratio was measured in the same manner as in Example 8. A photograph of the adhesive surface of Example 10 is shown in FIG. 9. The effective adhesive area ratio of the adhesive surface shown in FIG. 9 was 80%. Thereafter, the reseal strengths P1, P2, P3, P4, and P5 were determined in the same manner as in Example 8. The measurement results are shown in Table 2.

[0067] Example 11 A test film was prepared in the same manner as in Example 5. The heat seal strength P0 of this test film was measured in the same manner as in Example 8. Furthermore, the exposed effective adhesive area ratio was measured in the same manner as in Example 8. A photograph of the adhesive surface of Example 12 is shown in FIG. 10. The effective adhesive area ratio of the adhesive surface shown in FIG. 10 was 90%. Thereafter, the reseal strengths P1, P2, P3, P4, and P5 were determined in the same manner as in Example 8. The measurement results are shown in Table 2.

[0068] Comparative Example 4 A test film was prepared in the same manner as in Comparative Example 1. The heat seal strength P0 of this test film was measured in the same manner as in Example 8. Furthermore, the exposed effective adhesive area ratio was measured in the same manner as in Example 8. A photograph of the adhesive surface of Comparative Example 4 is shown in FIG. 11. The effective adhesive area ratio of the adhesive surface shown in FIG. 11 was 60%. Thereafter, the reseal strengths P1, P2, P3, P4, and P5 were determined in the same manner as in Example 8. The measurement results are shown in Table 2.

[0069] [Table 2]

[0070] Comparative Example 4, which does not have a non-sealed portion, had a higher heat seal strength and a lower initial ease of opening than Examples 8 to 11. That is, it was difficult to open in the early stages. In addition, the effective adhesive area ratio was low at 60%, and a large amount of peeled material Z of the sealant layer remained on the adhesive layer. On the other hand, in Examples 8 to 11, in which a non-sealed portion was arranged in the center of the resealed portion, the effective adhesive area ratio was higher. Furthermore, Examples 8 to 11 had a lower heat seal strength and a higher reseal strength than Comparative Example 4. When the non-sealed portion is arranged so that the boundary between the resealed portion and the non-sealed portion is recessed in the center, the force applied when peeling the sealed portion is transmitted in an oblique direction starting from the non-sealed portion, making it easier for the peeling to proceed smoothly, and it is considered that the sealant strength was reduced. In addition, since the sealant layer could be peeled off cleanly, the effective adhesive area ratio was higher, and it is considered that the reseal strength after resealing could be maintained high. Therefore, by positioning the non-sealed portion so that the boundary between the resealed portion and the non-sealed portion is recessed in the center, a packaging bag can be provided that is easy to open initially and can adequately maintain the sealing properties of the resealed portion after resealing, resulting in an excellent appearance of the adhesive surface. [Industrial Applicability]

[0071] According to the present disclosure, it is possible to provide a packaging bag that can improve the initial ease of opening while maintaining high reseal strength even after repeated opening and resealing. [Explanation of symbols]

[0072] 100, 101...packaging bag, 102...container, 120...seal bar, 1L...left side (first side), 1R...right side (second side), 1B...bottom, 1T...upper part, 11...front packaging film, 12...back packaging film, 20...resealing film, 21...first sealant layer, 22...adhesive layer, 23...second sealant layer, 31, 32, 33, 34...sealed part, 40... Tear start point, 50...half cut line, P0...heat seal strength, P1, P2, P3, P4, P5...reseal strength, Ar1...vertical direction, Ar2...horizontal direction, X1...upper end, X2...lower end, OP...entrance part, R...reseal part, W...width, D...height, N, N1, N2, N3, N4...non-sealed part, M...diagonal direction, P...virtual straight line, K1, K2...boundary line, Z...peel-off object.

Claims

1. One or more packaging films are joined together to form a bag having a storage section, A pair of side portions, a first side portion and a second side portion; a bottom portion connecting the first side portion and the second side portion; an inlet portion located on the opposite side to the bottom; A packaging bag comprising: a strip-shaped reseal portion that is resealably sealed so as to traverse between the first side portion and the second side portion, a boundary line between the resealing portion and a non-sealing portion on the inlet side of the resealing portion is recessed toward the storage portion at a central portion, A packaging bag, wherein the width of the resealable portion is narrower in the central portion than in the portions near the sides.

2. 2. The packaging bag according to claim 1, wherein when an imaginary line is drawn connecting both ends of the boundary line, the length of the imaginary line at a portion where the imaginary line deviates from the boundary line is 10 to 40 mm.

3. 3. The packaging bag according to claim 2, wherein the maximum distance between the imaginary line and the boundary line in a direction perpendicular to the imaginary line is 2.0 to 4.0 mm.

4. The packaging bag according to claim 1 or 2, wherein the boundary line has a V-shape in the central portion that narrows toward the storage section.

5. The resealing portion includes an adhesive layer and A sealant layer laminated on the pressure-sensitive adhesive layer, The packaging bag according to claim 1 or 2, wherein the pressure-sensitive adhesive layer is exposed when the opening is opened.

6. The packaging bag according to claim 5 , wherein the heat seal strength of the pressure-sensitive adhesive layer in the resealable portion is 27.0 [N / 30 mm width] or less.

7. The packaging bag according to claim 5, wherein P1 / P0 is 0.23 or more, where P0 is the heat seal strength when the resealable portion is opened and P1 is the reseal strength of the adhesive layer after a first resealing.

8. The packaging bag according to claim 5, wherein P3 / P0 is 0.19 or more, where P0 is the heat seal strength when the resealable portion is opened and P3 is the reseal strength of the pressure-sensitive adhesive layer after three repeated resealing operations.

9. The packaging bag according to claim 5 , wherein an effective adhesive area ratio of the adhesive layer when the resealable portion is opened is 70% or more.

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