Packaging bags

Abstract

To provide a packaging bag that can make a tear line follow a half-cut portion better.SOLUTION: A first half-cut portion 31 of a first sheet 21 included in a packaging bag 10 includes a central straight portion located in an area including a center of the first half-cut portion 31 in a length direction and a sloping portion connected to the central straight portion on the side where a seal portion 23 is located with respect to the central straight portion. The sloping portion has a plurality of sloping cut lines, which is a plurality of half-cut lines extending in a direction inclined with respect to the length direction. The ratio of the length of the sloping portion in the height direction to the length of the sloping portion in the length direction is 0.3 or less. The central straight portion has a half-cut line that linearly extends in the length direction where a plurality of sloping cut lines is aggregated and combined.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a packaging bag. [Background technology]

[0002] A packaging bag for containing food, cosmetics, medicine, or other contents has a structure in which the peripheral edges of two facing sheets are joined by heat sealing. The sheets have a half-cut portion that guides the position at which the sheet is torn when the packaging bag is opened. The half-cut portion is processed by making a cut in part of the sheet in the thickness direction. The half-cut portion extends linearly, for example, between the left and right ends of the packaging bag (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-100113 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to accurately open a packaging bag and facilitate removal of the contents, it is desirable that the tearing of the sheet proceeds along the half-cut portion, in other words, that the tear line closely follows the half-cut portion. The tear line is the location where the sheet is actually torn when the packaging bag is opened. Various proposals have been made regarding the shape and position of the half-cut portion, but there is still room for improvement in the configuration of the half-cut portion from the perspective of improving the followability of the tear line along the half-cut portion. [Means for solving the problem]

[0005] A packaging bag for solving the above-mentioned problems is a packaging bag comprising a first sheet and a second sheet facing each other, the packaging bag having a seal part at which the first sheet and the second sheet are joined at the periphery of the packaging bag, the first sheet having a first half-cut part extending from the seal part across the packaging bag, the first half-cut part being composed of a half-cut line which is a part where a slit extending linearly with a depth that does not penetrate the first sheet is located, the direction in which the first half-cut part extends is the length direction, and the direction perpendicular to the length direction along the surface of the first sheet is the height direction, The half-cut portion includes a central straight portion located in an area including the center of the first half-cut portion in the longitudinal direction, and an inclined portion connected to the central straight portion on the side of the central straight portion where the seal portion is located, the inclined portion having inclined cut lines which are the half-cut lines extending in a direction inclined with respect to the longitudinal direction, the ratio of the length of the inclined portion in the height direction to the length of the inclined portion in the longitudinal direction being 0.3 or less, and the central straight portion having the half-cut line which extends linearly along the longitudinal direction and is formed by aggregating and joining the multiple inclined cut lines.

[0006] According to the above configuration, the multiple oblique cut lines are joined at the central straight section, increasing the width of the half-cut lines at the central straight section. This reduces deviation of the tear line from the half-cut lines at the central straight section. Furthermore, because the ratio of the oblique section is 0.3 or less, the angle of the oblique section is prevented from becoming too steep, improving the ability of the tear line to follow the oblique section. These factors improve the ability of the tear line to follow the first half-cut section.

[0007] In the above configuration, of the two end portions of the packaging bag in the height direction, the end portion closest to the first half-cut portion is the upper end portion of the packaging bag, the inclined cut lines are inclined toward the central straight portion so as to approach the upper end portion, and the inclination angles of the multiple inclined cut lines with respect to the length direction may be smaller as the inclined cut lines are closer to the upper end portion.

[0008] According to the above configuration, it is possible to accurately converge the multiple oblique cut lines at the central straight section. Also, the first half-cut section can be configured so that the upper edge of the first sheet protrudes after the packaging bag is opened. Therefore, after opening the packaging bag, it is easy to open the packaging bag by pinching the upper edge of the first sheet.

[0009] In the aforementioned configuration, a ratio of a length of the inclined portion in the height direction to a length of the inclined portion in the length direction may be 0.12 or more. According to the above configuration, the length of the inclined portion is prevented from becoming excessive, and therefore the ability of the tear line to follow the inclined portion is improved, thereby improving the ability of the tear line to follow the first half-cut portion.

[0010] In the above configuration, the width of the half-cut line in the central straight line portion may be greater than the width of the oblique cut line, and may be 200 μm or more and 400 μm or less. According to the above configuration, the width of the half-cut line in the central straight portion is sufficiently ensured, thereby reliably preventing the tear line from shifting from the half-cut line, thereby improving the ability of the tear line to follow the first half-cut portion.

[0011] In the above configuration, the first half-cut portion may include an end straight portion at an end of the first half-cut portion in the longitudinal direction, the end straight portion being connected to the inclined portion on the opposite side of the central straight portion with respect to the inclined portion in the longitudinal direction, and the end straight portion may have a plurality of half-cut lines extending linearly along the longitudinal direction, with one half-cut line connected to each inclined cut line.

[0012] According to the above configuration, even if the position where the outer edge of the packaging bag is formed or the position where the opening start point is formed is shifted, the position where the tear line starts to be formed can be prevented from shifting from the first half-cut portion.

[0013] In the above configuration, the entire straight end portion may be located in the seal portion. According to the above configuration, the straight end portion is located in a harder seal portion compared to the area where the first sheet and the second sheet are not joined, so that the tear line tends to follow the first half-cut portion more stably at the transition point from the straight end portion to the inclined portion.

[0014] In the above configuration, the packaging bag has an opening starting point portion that functions as a starting point for opening the packaging bag, and the opening starting point portion extends from the outer edge of the packaging bag into the sealed portion, and the point of the opening starting point portion that is farthest from the outer edge of the packaging bag in the length direction is the end point of the opening starting point portion, and in the height direction, the position of the end point may be included in the range where the end portion opposite the central straight portion of the inclined portion is located.

[0015] According to the above configuration, even if a shift occurs in the formation position of the opening starting point portion, it is possible to prevent the end point of the opening starting point portion from shifting from the first half-cut portion, and the tear line is likely to follow the first half-cut portion near the inclined portion.

[0016] In the above configuration, the second sheet has a second half-cut portion extending from the sealed portion across the packaging bag in a direction consistent with the first half-cut portion, the second half-cut portion being composed of a half-cut line which is a portion where a linearly extending cut having a depth that does not penetrate the second sheet is located, and the half-cut line of the second half-cut portion may extend linearly along the direction in which the second half-cut portion extends. According to the above configuration, the second half-cut portion has a simple configuration and is easy to form.

[0017] In the above configuration, the position of the half-cut line of the second half-cut portion in the direction along the height direction may be included in the height range in which the end portion of the inclined portion opposite the central straight portion is located.

[0018] According to the above configuration, even if the positions of the first and second half-cut portions are misaligned in the height direction, the half-cut line of the central linear portion of the first half-cut portion and the half-cut line of the second half-cut portion are prevented from overlapping. Therefore, after opening, a step is formed between the upper edges of the first sheet and the second sheet. Therefore, an opener can easily grasp the area near the upper edge of the first sheet, making it easy to open the packaging bag.

[0019] In the above configuration, the first sheet may include a base layer, a sealant layer, and an intermediate layer located between the base layer and the sealant layer, the cut of the half-cut line extending through at least a portion of the base layer in the thickness direction, the sealant layer being joined to the second sheet at the seal portion, and the intermediate layer being a resin film having a metal vapor deposition film.

[0020] This configuration improves gas barrier properties and reduces the manufacturing cost of packaging bags compared to when the intermediate layer is a metal foil. Furthermore, there is a limit to the depth of the slit that can be formed while preventing damage to the intermediate layer, which is a resin film with a metal-deposited film. In contrast, the packaging bag improves the followability of the tear line by widening the half-cut line in the central linear portion. This effectively improves the followability of the tear line to the first half-cut portion, even when there is a limit to the depth of the slit that can be formed.

[0021] In the above configuration, the first sheet comprises a base layer, a sealant layer, and an intermediate layer located between the base layer and the sealant layer, the cut of the half-cut line runs through at least a part of the base layer in the thickness direction, the sealant layer is joined to the second sheet at the seal portion, and in the cross section of the first sheet, raised portions that are raised relative to the surface of the base layer are located on both sides of the half-cut line in the width direction. According to the above configuration, the tearing of the first sheet along the half-cut line is less likely to deviate from the half-cut line.

[0022] In the above configuration, the inclined portion may have three or more inclined cut lines. According to the above configuration, it is easier to ensure a larger width of the half-cut line in the central straight portion, which effectively prevents the tear line from shifting from the half-cut line, thereby improving the ability of the tear line to follow the first half-cut portion. [Effects of the Invention]

[0023] According to the present invention, it is possible to improve the ability of the tear line to follow the half-cut portion. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a diagram showing the overall configuration of a packaging bag according to an embodiment. [Figure 2] 3 is an enlarged view showing the vicinity of a first half-cut portion in the packaging bag of one embodiment. FIG. [Figure 3] FIG. 3 is a diagram showing a cross-sectional structure of a first sheet at an inclined portion in a packaging bag of one embodiment. [Figure 4] 3 is a diagram showing the cross-sectional structure of the first sheet at the central straight portion in the packaging bag of one embodiment. FIG. [Figure 5] 3A and 3B are diagrams showing the configuration of a second sheet of a packaging bag according to one embodiment. [Figure 6] 4 is a diagram showing the positional relationship between a first half-cut portion and a second half-cut portion in a packaging bag of one embodiment. FIG. [Figure 7] FIG. 10 is a diagram showing an opened packaging bag in one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] An embodiment of the packaging bag will be described with reference to the drawings. In the following description, the up-down direction refers to the opening direction when the packaging bag is opened, i.e., the direction from the inside of the packaging bag to the outside through the opening formed by opening is defined as the up direction.

[0026] [Overall structure of packaging bag] The overall structure of the packaging bag will be described with reference to Figure 1. As shown in Figure 1, packaging bag 10 includes a first sheet 21 and a second sheet 22 that face each other. Packaging bag 10 has a sealed portion 23 where first sheet 21 and second sheet 22 are joined together in the peripheral portion, which is the area along the outer edge of packaging bag 10. In sealed portion 23, first sheet 21 and second sheet 22 are joined together by thermal fusion using heat sealing. In packaging bag 10, the area where first sheet 21 and second sheet 22 face each other without being joined together, in other words, the area other than sealed portion 23, is a bag portion 24.

[0027] 1 shows an example in which the packaging bag 10 is a four-sided sealed bag. In this case, the packaging bag 10 has a substantially rectangular outer shape when viewed from a position facing the first sheet 21, and the entire peripheral area along the four sides of the rectangle is the sealed portion 23.

[0028] The outer edges of the packaging bag 10 include a first side edge 11 and a second side edge 12. A bag portion 24 is sandwiched between the first side edge 11 and the second side edge 12. The packaging bag 10 is opened by tearing the sheets 21, 22 from the first side edge 11 toward the second side edge 12. For example, when the packaging bag 10 has a substantially rectangular shape, the first side edge 11 is along one of two opposing sides that extend in the vertical direction of the rectangle, and the second side edge 12 is along the other of the two sides.

[0029] The packaging bag 10 has an opening guide portion 30 that extends from the first side edge 11 toward the second side edge 12. The opening guide portion 30 traverses the packaging bag 10 between the first side edge 11 and the second side edge 12, passing through the seal portion 23 and the bag portion 24. The opening guide portion 30 has the function of guiding the position at which the sheets 21, 22 are to be torn when the packaging bag 10 is opened. The direction in which the opening guide portion 30 extends is the left-right direction. The left-right direction is perpendicular to the up-down direction.

[0030] The packaging bag 10 further includes a resealing member 25. The resealing member 25 has the function of enabling the packaging bag 10 to be repeatedly resealed and re-opened after it has been opened. The resealing member 25 is provided in the bag portion 24 between the first side edge 11 and the second side edge 12, and extends in the same direction as the opening guide portion 30. The resealing member 25 may be, for example, a resin zipper that has a strip-shaped protrusion and a strip-shaped groove and enables sealing by fitting the protrusion and the groove together, or may be an adhesive sticker that can be repeatedly peeled and attached.

[0031] Opening guide part 30 and resealing member 25 are located at the top of packaging bag 10. Opening guide part 30 is located between resealing member 25 and the upper end of packaging bag 10. The contents are stored in the part of bag part 24 on the opposite side of resealing member 25 from opening guide part 30. The contents are not particularly limited and may be, for example, food, cosmetics, medicines, etc.

[0032] An opening starting point 26 is provided in the sealed portion 23 from the first side edge 11 toward the end of the opening guide portion 30. The opening starting point 26 functions as a starting point for tearing the sheets 21, 22 when the packaging bag 10 is opened. The opening starting point 26 has a structure in which the force applied to the sealed portion 23 when opening tends to be concentrated at the end of the opening starting point 26, or a structure in which the strength of the opening starting point 26 is weaker than other parts of the sealed portion 23.

[0033] For example, the opening starting point 26 may have a structure in which the sealed portion 23 is cut out in a shape such as a triangle, or may have a structure in which a linear cut is made in the sealed portion 23. Alternatively, the opening starting point 26 may be a portion that has been subjected to weakening processing that reduces the strength of the sealed portion 23 by forming minute through holes or the like.

[0034] The packaging bag 10 may be openable from either the direction from the first side edge 11 toward the second side edge 12 or the direction from the second side edge 12 toward the first side edge 11. In this case, as shown in Fig. 1, an opening starting point portion 26 is provided in the sealed portion 23 from the second side edge 12 toward the end of the opening guide portion 30, and the opening guide portion 30 has a bilaterally symmetrical shape.

[0035] The packaging bag 10 is not limited to a four-sided sealed bag, but may also be a three-sided sealed bag or a stand-up pouch. When the packaging bag 10 is a three-sided sealed bag, the first sheet 21 and the second sheet 22 are continuous at a part of the peripheral edge of the packaging bag 10. When the packaging bag 10 is a stand-up pouch, a sheet that forms the bottom of the packaging bag 10 is located between the first sheet 21 and the second sheet 22 at the bottom of the packaging bag 10. The outer shape of the packaging bag 10 is not limited to a rectangular shape. In short, the packaging bag 10 may be a bag-shaped structure having the opening guide portion 30, and the seal portion 23 may be located at least in a portion of the peripheral edge of the packaging bag 10 along the first side edge 11.

[0036] [Configuration of the opening guidance section] The opening guide portion 30 has a first half-cut portion 31 provided in the first sheet 21 and a second half-cut portion 32 provided in the second sheet 22. First, the detailed configuration of the first half-cut portion 31 will be described.

[0037] <First half-cut section> 2, the first half-cut portion 31 includes an end straight portion 33, an inclined portion 34, and a central straight portion 35, and is configured by a half-cut line 40. The half-cut line 40 is a portion where a cut that extends linearly and has a depth that does not penetrate the first sheet 21 is located.

[0038] The end straight portion 33 is located at the end in the length direction, which is the direction in which the first half-cut portion 31 extends. The length direction coincides with the left-right direction of the packaging bag 10. The end straight portion 33 is connected to the inclined portion 34, which is further connected to the central straight portion 35. That is, from the position closest to the first side edge 11, the end straight portion 33, the inclined portion 34, and the central straight portion 35 are lined up in this order.

[0039] Although not shown in Figure 2, when the opening guide portion 30 has a bilaterally symmetrical structure, the end straight portion 33, the inclined portion 34, the central straight portion 35, the inclined portion 34, and the end straight portion 33 are arranged in this order from the first side edge 11 to the second side edge 12. The central straight portion 35 is located in an area including the center of the first half-cut portion 31 in the longitudinal direction, and the inclined portion 34 and the end straight portion 33 are located on the side of the central straight portion 35 where the sealed portion 23 is located in the longitudinal direction.

[0040] The end straight section 33 is composed of three half-cut lines 40: an upper cut line 41a, a central cut line 41b, and a lower cut line 41c. These cut lines 41a, 41b, and 41c all extend linearly along the length direction and are arranged at equal intervals along the height direction, which is perpendicular to the length direction. Each of these cut lines 41a, 41b, and 41c is an end cut line.

[0041] In the height direction, the central cut line 41b is located between the upper cut line 41a and the lower cut line 41c. The height direction is the same as the up-and-down direction of the packaging bag 10, and the upper cut line 42a is located above the central cut line 42b, and the lower cut line 42c is located below the central cut line 42b.

[0042] The central straight portion 35 is composed of a single half-cut line 40, i.e., an aggregate cut line 43. The aggregate cut line 43 extends linearly along the length direction. In the height direction, the aggregate cut line 43 is positioned closer to the upper end of the packaging bag 10 than the cut lines 41a, 41b, and 41c of the end straight portion 33.

[0043] The inclined portion 34 is composed of three half-cut lines 40: an upper cut line 42a, a middle cut line 42b, and a lower cut line 42c. All of these cut lines 42a, 42b, and 42c extend in a direction inclined relative to the longitudinal direction. Each of these cut lines 42a, 42b, and 42c is an inclined cut line.

[0044] In the height direction, the central cut line 42b is located between the upper cut line 42a and the lower cut line 42c. The upper cut line 42a is located above the central cut line 42b, and the lower cut line 42c is located below the central cut line 42b.

[0045] One end of the upper cut line 42a is connected to the upper cut line 41a of the end straight portion 33, and the other end of the upper cut line 42a is connected to the collecting cut line 43. One end of the central cut line 42b is connected to the central cut line 41b of the end straight portion 33, and the other end of the central cut line 42b is connected to the collecting cut line 43. One end of the lower cut line 42c is connected to the lower cut line 41c of the end straight portion 33, and the other end of the lower cut line 42c is connected to the collecting cut line 43.

[0046] The upper cut line 42a, the central cut line 42b, and the lower cut line 42c are each inclined relative to the longitudinal direction so as to approach the upper end of the packaging bag 10 toward the central straight line portion 35. The inclination angle of each cut line 42a, 42b, and 42c relative to the longitudinal direction is different from one another. The inclination angle is greatest for the lower cut line 42c, and decreases in the order of the central cut line 42b and the upper cut line 42a. In other words, the inclination angle of the cut line closer to the upper end of the packaging bag 10 is smaller.

[0047] As described above, in the first half-cut portion 31, the three half-cut lines 40 that make up the end straight portion 33 and the inclined portion 34 are aggregated at the central straight portion 35 to form a single half-cut line 40. The line width of the aggregated cut line 43 is greater than the line widths of the cut lines 41a to 41c, 42a to 42c of the end straight portion 33 and the inclined portion 34.

[0048] The following describes the positional relationship between the first half-cut portion 31, the opening starting point 26, and the sealed portion 23. The opening starting point 26 extends into the sealed portion 23 from the first side edge 11. The end point T of the opening starting point 26 is the point in the opening starting point 26 that is farthest from the first side edge 11 in the length direction, in other words, the point in the opening starting point 26 that is closest to the bag portion 24.

[0049] The opening starting point 26 is arranged so that the end point T is located in the range in the height direction where the straight end portion 33 is located. That is, in the height direction, the position of the end point T is included in the range from the position of the upper cut line 41a to the position of the lower cut line 41c. FIG. 2 illustrates an example in which the position of the end point T coincides with the position of the central cut line 41b, but the position of the end point T may be deviated from the position of the central cut line 41b as long as it is included in the range from the upper cut line 41a to the lower cut line 41c. Also, in FIG. 2, each of the cut lines 41a, 41b, and 41c extends until it reaches the opening starting point 26, but there may be a gap between the opening starting point 26 and at least one of the cut lines 41a, 41b, and 41c.

[0050] In the above configuration, the position of the end point T in the height direction is included in the range where the end of the inclined portion 34 is located on the opposite side from the central straight portion 35. That is, in the height direction, the position of the end point T is included in the range from the end of the upper cut line 42a on the first side edge 11 side to the end of the lower cut line 42c on the first side edge 11 side.

[0051] The entire straight edge portion 33 is located in the sealed portion 23, and the boundary between the straight edge portion 33 and the inclined portion 34 is located in the sealed portion 23. The boundary between the sealed portion 23 and the bag portion 24 overlaps with the inclined portion 34. That is, a part of the inclined portion 34 is located in the sealed portion 23, and the remainder of the inclined portion 34 is located in the bag portion 24. The central straight edge portion 35 is located in the bag portion 24.

[0052] Since the sealed portion 23 is harder than the bag portion 24, the transition position from the straight edge portion 33 to the inclined portion 34 is included in the sealed portion 23, and therefore the tear line tends to stably follow the half-cut line 40 at the transition position. The tear line is the position where the sheets 21, 22 are actually torn when the packaging bag 10 is opened.

[0053] By positioning the straight edge portion 33 at the end of the first half-cut portion 31, even if there is a shift in the position of the opening starting point 26 or the position of the first side edge 11 relative to the sheets 21, 22 in the longitudinal direction, it is possible to prevent the end point T from shifting from the first half-cut portion 31. To achieve this effect, the length Le of the straight edge portion 33 is preferably 1.0 mm or more. The length Le of the straight edge portion 33 is the length of the region inward of the end point T of the opening starting point 26 in the longitudinal direction, in other words, the length of the straight edge portion 33 in the region closer to the bag portion 24 than the end point T.

[0054] Furthermore, since the end straight portion 33 and the inclined portion 34 are composed of multiple half-cut lines 40, even if there is a shift in the formation position of the opening starting point 26 in the vertical direction, the end point T can be prevented from shifting from the first half-cut portion 31, compared to when the end straight portion 33 and the inclined portion 34 are composed of a single half-cut line 40.

[0055] If the length Le of the straight edge portion 33 is too large, the direction of the force applied to the straight edge portion 33 when the packaging bag 10 is opened will be dispersed along the straight edge portion 33, making it easier for the tear line to meander along the straight edge portion 33. As a result, the tear line will be less likely to be guided to the aggregated cut line 43 of the central straight portion 35, reducing the ability of the tear line to follow the first half-cut portion 31 and making it easier for the constituent layers of the first sheet 21 to peel off and for thread-like fragments, which are thread-like pieces of the first sheet 21, to form near the tear line. In order to improve the ability of the tear line to follow the tear line and prevent the peeling of the constituent layers and the formation of thread-like fragments, the length Le of the straight edge portion 33 is preferably 2.0 mm or less.

[0056] The interval Pe between the cut lines 41a to 41c in the height direction in the end straight portion 33 is preferably 1.0 mm or less. This prevents the height Hi of the inclined portion 34 from becoming too large, making it easier to prevent the inclination angle of the inclined portion 34 from becoming too steep.

[0057] The height Hi of the inclined portion 34 is the length of the area in which the inclined portion 34 is located in the height direction, and is the length in the height direction between the end of the lower cut line 42c on the side of the end straight portion 33 and the end of the upper cut line 42a on the side of the central straight portion 35. The height Hi of the inclined portion 34 is, for example, 1.0 mm or more and 3.0 mm or less. The length Li of the inclined portion 34 is the length between both ends of the inclined portion 34 in the length direction. The length Li of the inclined portion 34 is, for example, 10 mm or more and 30 mm or less.

[0058] The ratio of the height Hi to the length Li of the inclined portion 34 is 0.3 or less. This prevents the inclination angle of the inclined portion from being too steep, thereby preventing the angle of the half-cut line 40 from changing too much as it passes from the end straight portion 33 through the inclined portion 34 to the central straight portion 35. As a result, the tear line is more easily guided along the half-cut line 40 from the end straight portion 33 to the inclined portion 34 and from the inclined portion 34 to the central straight portion 35, improving the ability of the tear line to follow the first half-cut portion 31.

[0059] Furthermore, if the length Li of the inclined portion 34 is too large, the tear line will meander at the inclined portion 34, reducing the ability of the tear line to follow the first half-cut portion 31 and increasing the likelihood of peeling of the constituent layers of the first sheet 21 or the generation of thread-like fragments. To prevent this, the length Li of the inclined portion 34 is preferably 25 mm or less, and the ratio of the height Hi to the length Li of the inclined portion 34 is preferably 0.12 or greater.

[0060] In order to improve the tear line followability as well as to prevent peeling of the constituent layers and the generation of thread-like fragments, the ratio of the height Hi to the length Li of the inclined portion 34 is preferably 0.2 or less, and most preferably 0.2. The length of the central straight section 35 may be set according to the size of the packaging bag 10 in the left-right direction.

[0061] The cross-sectional structure of the first half-cut portion 31 will be described with reference to Figures 3 and 4. Figures 3 and 4 are cross sections of the first sheet 21 taken along the width direction of the half-cut line 40, with Figure 3 showing a cross section of the inclined portion 34 and Figure 4 showing a cross section of the central straight portion 35.

[0062] First, we will explain the layer structure of the first sheet 21. As shown in Figures 3 and 4, the first sheet 21 includes a base material layer 50, an intermediate layer 51, and a sealant layer 52. The base material layer 50 faces the outside of the packaging bag 10, and the sealant layer 52 faces the inside of the packaging bag 10. The intermediate layer 51 is located between the base material layer 50 and the sealant layer 52.

[0063] The material of the base layer 50 is preferably a resin such as polyethylene terephthalate, polyester, polypropylene, polystyrene, nylon, polycarbonate, polyacrylonitrile, or polyimide. The polyethylene terephthalate may be recycled polyethylene terephthalate regenerated by mechanical recycling or chemical recycling. The base layer 50 may be a uniaxially stretched film, a biaxially stretched film, or a non-stretched film. The base layer 50 may be paper or nonwoven fabric as long as the half-cut line 40 can be formed. The base layer 50 may be a single layer or a laminate of multiple layers.

[0064] Intermediate layer 51 has a function of suppressing the permeation of water vapor, oxygen, etc., i.e., gas barrier properties. Intermediate layer 51 is, for example, a metal foil such as aluminum, a resin film vapor-deposited with a metal such as aluminum, or a resin film vapor-deposited with an inorganic oxide such as aluminum oxide. Examples of resin films include polyethylene terephthalate film and polyester film. In particular, when intermediate layer 51 is a resin film having a vapor-deposited metal film, the gas barrier properties are improved and the manufacturing costs of packaging bag 10 can be reduced compared to when intermediate layer 51 is a metal foil.

[0065] Intermediate layer 51 may be a layer for improving the rigidity and mechanical strength of first sheet 21. In this case, intermediate layer 51 may be a film made of a resin such as nylon or polyester.

[0066] The sealant layer 52 is made of a resin that melts when heated, and is joined to the second sheet 22 by heat fusion. The material of the sealant layer 52 is, for example, a polyolefin resin. Specific examples of polyolefin resins include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer, ionomer, polypropylene, etc. The sealant layer 52 may be a single layer or a laminate of multiple layers.

[0067] The base layer 50 and the intermediate layer 51 are bonded together by an adhesive layer (not shown), and the intermediate layer 51 and the sealant layer 52 are also bonded together by an adhesive layer (not shown). For example, a dry lamination adhesive is used as the material for the adhesive layer, and the layers are bonded together by a dry lamination method. Examples of adhesives include two-component curing urethane adhesives, polyester urethane adhesives, polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, and epoxy adhesives.

[0068] Similarly to the first sheet 21, the second sheet 22 includes a base layer 50, an intermediate layer 51, and a sealant layer 52. In the seal portion 23, the sealant layer 52 of the first sheet 21 and the sealant layer 52 of the second sheet 22 are joined by thermal fusion.

[0069] The half-cut lines 40 are preferably formed by laser processing. The type of laser is, for example, a carbon dioxide laser. When the half-cut lines 40 are formed by laser processing on the base layer 50 made of resin, raised portions 45 that rise above the surface 50S of the base layer 50 are formed on both sides of the half-cut lines 40 in the width direction. The raised portions 45 are formed by deformation of the resin film that is the base layer 50 at the positions of the half-cut lines 40 due to laser energy. By positioning the raised portions 45 on both sides of the half-cut line 40, the tearing of the first sheet 21 along the half-cut line 40 is less likely to deviate from the half-cut line 40.

[0070] At the half-cut line 40, at least a portion of the base material layer 50 is missing in the thickness direction of the first sheet 21. In other words, a groove, which is a cut, runs through at least a portion of the base material layer 50. Although FIGS. 3 and 4 illustrate a case where the entire base material layer 50 is missing at the half-cut line 40, a portion of the base material layer 50 may remain. Furthermore, in order to prevent a decrease in the functionality of the intermediate layer 51, such as gas barrier properties, it is preferable that the intermediate layer 51 is not missing at the half-cut line 40.

[0071] From the viewpoint of improving the ability of the tear line to follow the first half-cut portion 31 and suppressing deterioration in the functionality of the intermediate layer 51, it is preferable that the entire base material layer 50 is missing at the half-cut line 40, but the entire intermediate layer 51 is not missing. In other words, it is preferable that the groove, which is the cut, penetrates the base material layer 50 but does not reach the intermediate layer 51.

[0072] The width Wi of each of the cut lines 42a to 42c in the inclined portion 34 is, for example, not less than 80 μm and not more than 150 μm. The width Wc of the aggregated cut line 43 in the central straight portion 35 is larger than the width Wi of the cut lines 42a to 42c. The width Wc is preferably not less than 200 μm and not more than 400 μm.

[0073] The widths Wi and Wc are the widths of the half-cut lines 40 at the positions where the width of the half-cut lines 40 is greatest below the surface 50S of the base layer 50. Normally, the width of the half-cut lines 40 varies in the thickness direction and is greatest at the position of the surface 50S. The width of each of the cut lines 41a to 41c in the end straight portion 33 is equal to the width Wi of each of the cut lines 42a to 42c in the inclined portion 34.

[0074] When forming half-cut line 40 by laser processing, laser scanning is performed consecutively to form upper cut lines 41a and 42a, laser scanning consecutively to form central cut lines 41b and 42b, and laser scanning consecutively to form lower cut lines 41c and 42c to form aggregated cut line 43. That is, laser irradiation consecutively to form end straight portion 33 and inclined portion 34 is performed with scan line spacing narrower than end straight portion 33 and inclined portion 34, thereby forming one aggregated cut line 43 in central straight portion 35.

[0075] In this way, the aggregated cut line 43 is a half-cut line 40 in which the three cut lines 42a, 42b, and 42c in the inclined portion 34 are aggregated and joined to each other at the central straight portion 35. Therefore, the width Wc of the aggregated cut line 43 is close to the combined width Wi of the three cut lines 42a, 42b, and 42c.

[0076] In this embodiment, one half-cut line 40 refers to a structure that does not have a raised portion having a height equal to or higher than the raised portions 45 at both ends in the width direction between the raised portions 45 at both ends. The area between the raised portions 45 at both ends does not have to be flat, and one half-cut line 40 may have a raised portion between the raised portions 45 at both ends that is lower than the raised portions 45 at both ends.

[0077] <Second half cut section> The configuration of the second half-cut portion 32 provided in the second sheet 22 will be described with reference to Figures 5 and 6. Figure 5 shows the packaging bag 10 as seen from a position opposite the second sheet 22.

[0078] As shown in FIG. 5 , the second half-cut portion 32 is composed of a single straight cut line 44, which is a half-cut line. The straight cut line 44 is a portion where a slit extending linearly is located that has a depth that does not penetrate the second sheet 22. The straight cut line 44 extends linearly throughout the entire length of the second half-cut portion 32. The extension direction of the second half-cut portion 32 is the same as the extension direction of the first half-cut portion 31, and is the left-right direction of the packaging bag 10. In other words, the first half-cut portion 31 and the second half-cut portion 32 have the same length direction and height direction.

[0079] The cross-sectional shape of the straight cut lines 44 is similar to the cross-sectional shape of the half-cut lines 40 of the first half-cut portion 31. The width of the straight cut lines 44 is equal to the width Wi of each of the cut lines 42a to 42c in the inclined portion 34 and is smaller than the width Wc of the collective cut lines 43 in the central straight portion 35.

[0080] The positional relationship between the first half-cut portion 31 and the second half-cut portion 32 will be described with reference to Figure 6. In the height direction, the position of the straight cut line 44 is included in the range where the end straight portion 33 is located. That is, in the height direction, the position of the straight cut line 44 is included in the range from the position of the upper cut line 41a to the position of the lower cut line 41c. The straight cut line 44 extends from, for example, the end point T of the opening starting point portion 26.

[0081] FIG. 6 illustrates an example in which the position of the straight cut line 44 coincides with the position of the central cut line 41b, but the position of the straight cut line 44 may deviate from the position of the central cut line 41b as long as it is included in the range from the upper cut line 41a to the lower cut line 41c.

[0082] In the above configuration, the position of the straight cut line 44 in the height direction is included in the range where the end of the inclined portion 34 is located on the opposite side from the central straight portion 35. That is, in the height direction, the position of the straight cut line 44 is included in the range from the end of the upper cut line 42a on the first side edge 11 side to the end of the lower cut line 42c on the first side edge 11 side. In the height direction, the position of the straight cut line 44 is different from the position of the collecting cut line 43 of the central straight portion 35. The position of the straight cut line 44 is lower than the position of the collecting cut line 43.

[0083] [Effect] The function of opening guide portion 30 in packaging bag 10 will be described. When opening packaging bag 10, the opener applies force to packaging bag 10 by pinching and pulling the vicinity of opening starting point 26. This causes tearing of first sheet 21 and second sheet 22 to begin near end point T of opening starting point 26.

[0084] Since the end point T is located in the range in the height direction where the end straight portion 33 is located, the tear line extending from the vicinity of the end point T is likely to fall within the range where the end straight portion 33 is located, that is, the tear line is likely to follow the first half-cut portion 31 near the end straight portion 33 and the inclined portion 34. Furthermore, since the multiple half-cut lines 40 in the inclined portion 34 are gathered at the central straight portion 35, the tear line is likely to be guided to the gathered cut line 43 in the central straight portion 35.

[0085] The tearing speed tends to increase in the center of the packaging bag 10, and since the central straight portion 35 is long, if the width of the half-cut lines 40 is small, the tear line is likely to deviate from the half-cut lines 40. Even if multiple half-cut lines 40 are arranged, if the width of each half-cut line 40 is small, there is a limit to how much the tear line can be prevented from deviating from the opening guide portion 30.

[0086] In contrast, in this embodiment, the multiple half-cut lines 40 are gathered at the central straight portion 35, and the width of the gathered cut lines 43 is increased at the central straight portion 35. Therefore, deviation of the tear line from the gathered cut lines 43 is suitably suppressed, and the ability of the tear line to follow the first half-cut portion 31 is improved.

[0087] As described above, in order to improve the ability of the tear line to follow the first half-cut portion 31 and to prevent a decrease in the functionality of the intermediate layer 51, it is preferable that the slits that make up the half-cut line 40 penetrate the base material layer 50 but do not reach the intermediate layer 51. If the intermediate layer 51 is a metal foil, the intermediate layer 51 is less likely to be destroyed by laser irradiation, making it easy to form deep slits that destroy only the base material layer 50. On the other hand, if the intermediate layer 51 is a resin film having a metal vapor deposition film, the intermediate layer 51 is more likely to be destroyed by laser irradiation, so there is a limit to the depth of the slit that can be formed without destroying the intermediate layer 51.

[0088] In this embodiment, the width of the half-cut line 40 is widened at the central straight section 35 to improve the followability of the tear line, so that even if there is a limit to the depth of the cut, the followability of the tear line to the first half-cut section 31 can be suitably improved.

[0089] 7 is a view of the upper portion of the packaging bag 10 after opening, viewed from a position facing the second sheet 22. Because the position of the straight cut line 44 of the second sheet 22 is below the position of the aggregate cut line 43 of the first sheet 21, the upper edges of the first sheet 21 and the second sheet 22 are misaligned after opening. The upper edge of the first sheet 21 protrudes upward beyond the upper edge of the second sheet 22. Therefore, an opener can easily grasp the vicinity of the upper edge of the first sheet 21. This makes it easy to separate the first sheet 21 and the second sheet 22 and open the resealing member 25.

[0090] In the height direction, the position of the straight cut line 44 is included in the range where the end straight portion 33 is located, so even if there is a deviation in the formation positions of the first half-cut portion 31 and the second half-cut portion 32 in the height direction, the straight cut line 44 is prevented from overlapping the gathering cut line 43. Therefore, it is possible to accurately ensure the difference in level between the upper edge of the first sheet 21 and the upper edge of the second sheet 22 after opening.

[0091] [Example] The above-mentioned packaging bag will be described using specific examples and comparative examples. Example 1 A packaging bag of Example 1, which is a four-sided sealed bag, was produced. In each of the first and second sheets, the base layer was a mechanically recycled polyethylene terephthalate film, the middle layer was an aluminum-deposited polyethylene terephthalate film, and the sealant layer was an unstretched polypropylene film. The thickness of the base layer was 12 μm, the thickness of the middle layer was 12 μm, and the thickness of the sealant layer was 40 μm. An adhesive was used to bond the layers together. The adhesive material was polyethylene, and the thickness of the adhesive layer was 30 μm.

[0092] A carbon dioxide laser was used to form the half-cut lines. The configuration of the first half-cut section is as follows: The shape of the first half-cut section is symmetrical, and the entire length of the first half-cut section is 18 cm.

[0093] Length of straight end section Le: 2.0 mm Distance between half-cut lines in the straight edge section Pe: 1.0 mm Length of inclined part Li: 15 mm Inclined part height Hi: 3.0 mm Interval of laser scanning lines in the central straight section: 0.1 mm

[0094] The height position of the straight cut line in the second half cut portion coincides with the position of the center cut line of the straight end portion in the first half cut portion. The opening starting point portion is a triangular cutout, and the height position of the end point of the opening starting point portion coincides with the position of the center cut line of the straight end portion.

[0095] (Examples 2 to 11, Comparative Examples 1 to 5) Packaging bags of Examples 2 to 11 and Comparative Examples 1 to 5 were produced using the same materials and manufacturing methods as in Example 1, except that the configuration of the first half-cut portion was changed.

[0096] In Comparative Example 1 and Examples 2 to 5, the length Li of the inclined portion was changed from that of Example 1. In Examples 6 and 7, the interval Pe between the half-cut lines in the straight edge portion and the height Hi of the inclined portion were changed compared to Example 1. In Examples 8 to 11, the length Le of the end straight portion was changed from that of Example 1. In Comparative Examples 2 to 5, the interval between the scanning lines of the laser irradiation in the central linear portion was changed compared to Example 1. Table 1 shows the configuration of the first half-cut portion in each example and each comparative example.

[0097] [Table 1]

[0098] (Evaluation method) For the Examples and Comparative Examples, cross-section observation of the central straight section and an opening test of the packaging bag were carried out by the following method. The evaluation results of the opening test of the packaging bag are shown in Table 1 above.

[0099] <Cross-section observation> The cross section of the central straight section of Example 1 and Comparative Examples 2 to 5 was observed using an electron microscope. As a result, in Example 1, one half-cut line with raised portions on both ends was formed. The groove in the half-cut line penetrated the base layer but did not reach the intermediate layer. The width of the half-cut line was 355 μm.

[0100] In Comparative Examples 2 to 5, three half-cut lines with raised portions at both ends were formed. The raised portions between adjacent half-cut lines were joined to form a single block. The grooves in the half-cut lines penetrated the base layer but did not reach the intermediate layer. The width of each half-cut line was approximately 130 μm to 140 μm.

[0101] From the above results, it was confirmed that in Example 1, a single aggregated cut line was formed in which multiple half-cut lines were joined, whereas in Comparative Examples 2 to 5, the half-cut lines were not joined but remained separate due to the large spacing between the laser irradiation scanning lines in the central straight section.

[0102] <Opening test> For each example and comparative example, a test was conducted in which the packaging bag was manually torn from the opening starting point for three samples. After tearing, the condition of the first sheet near the first half-cut portion was visually observed, and the tear line followability, presence or absence of peeling of the base layer, and presence or absence of formation of thread-like pieces were evaluated.

[0103] The tear line conformance was evaluated on a four-point scale. The location of the tear line was defined as the break in the base layer, and the percentage of the area where the first half-cut section and the tear line coincided along the length of the first half-cut section was measured for each sample. The average of the measurement results for three samples was calculated. The tear line conformance was evaluated as follows: 90% or more of the average conformance was given a rating of "4," 70% or more but less than 90% was given a rating of "3," 50% or more but less than 70% was given a rating of "2," and less than 50% was given a rating of "1."

[0104] The presence or absence of peeling of the base material layer was evaluated using a three-point scale. Peeling was considered to have occurred when peeling of the base material layer occurred near the tear line, exposing the intermediate layer. If none of the three samples had peeling, it was given a rating of "3," if one sample had peeling, it was given a rating of "2," and if two or more samples had peeling, it was given a rating of "1."

[0105] The presence or absence of thread-like fragments was evaluated using a three-point scale. If thread-like fragments, which are thread-like pieces of the first sheet, were formed near the tear line, they were considered to be present. If none of the three samples had thread-like fragments, it was given a rating of "3," if one sample had thread-like fragments, it was given a rating of "2," and if two or more samples had thread-like fragments, it was given a rating of "1."

[0106] In Comparative Examples 4 and 5, the tear line followability was particularly poor, and a band-like region remained along the first half-cut portion. Therefore, in Comparative Examples 4 and 5, the peeling of the base layer and the presence or absence of thread-like pieces were not evaluated.

[0107] (Evaluation results) As shown in Table 1 above, Comparative Examples 2 to 5, in which the half-cut lines were not bonded but separated at the central straight portion, had poor tear line followability, and also received low ratings for peeling of the base layer and the presence of thread-like pieces. In contrast, Examples 1 to 11, in which the half-cut lines were bonded at the central straight portion, had higher tear line followability than Comparative Examples 2 to 5. Note that Comparative Example 1 also had poor tear line followability, despite the half-cut lines being bonded at the central straight portion. While Examples 1 to 11 had a ratio of the height to the length Li of the inclined portion (Hi / Li) of 0.3 or less, Comparative Example 1 had a Hi / Li ratio exceeding 0.5, which was significantly higher than the Examples. Therefore, it is believed that Comparative Example 1 had poor tear line followability due to the abrupt change in the angle of the half-cut lines from the end straight portions through the inclined portions to the central straight portion.

[0108] Comparing Examples 1 to 5, it was confirmed that Examples 1 to 4, in which Hi / Li is 0.12 or more, exhibited particularly good tear line followability, compared to Example 5, in which the length Li of the inclined portion 34 was long and Hi / Li was 0.1. Furthermore, Examples 1, 3, and 4, in which Hi / Li is 0.2 or less, suppressed peeling of the base layer, and in particular, Example 1, in which Hi / Li was 0.2, favorably suppressed both peeling of the base layer and the generation of thread-like fragments.

[0109] Furthermore, comparing Example 1 with Examples 6 to 11, it was confirmed that when the spacing Pe of the half-cut lines in the straight edge portion is small and the height Hi of the inclined portion 34 is small, the tear line tends to be somewhat poorer in terms of followability, and the base material layer tends to peel off and thread-like fragments tend to form more easily. Similarly, when the length Le of the straight edge portion is short or long, the tear line tends to be somewhat poorer in terms of followability, and the base material layer tends to peel off and thread-like fragments tend to form more easily. In particular, when the length Le of the straight edge portion is long, the frequency of both base material layer peeling and thread-like fragments increases.

[0110] In Example 1, the length Le of the straight end portion is 2.0 mm, the spacing Pe of the half-cut lines in the straight end portion is 1.0 mm, the length Li of the inclined portion is 15 mm, and the height Hi of the inclined portion is 3.0 mm. This configuration is said to be most suitable from the standpoint of improving the tracking ability of the tear line and suppressing peeling of the base material layer and the generation of thread-like fragments.

[0111] As described above in the embodiments and examples, the packaging bag can provide the following effects. (1) In the first half-cut portion 31, the inclined portion 34 has a plurality of half-cut lines 40 inclined with respect to the length direction, and the central straight portion 35 has a straight half-cut line 40 formed by collecting and joining the plurality of half-cut lines 40 from the inclined portion 34. As a result, the width of the half-cut lines 40 in the central straight portion 35 is increased, which effectively prevents the tear line from shifting from the half-cut lines 40. This improves the ability of the tear line to follow the first half-cut portion 31.

[0112] (2) The half-cut lines 40 of the inclined portion 34 are inclined toward the central straight portion 35 so as to approach the upper end of the packaging bag 10, and the inclination angle of the multiple half-cut lines 40 becomes smaller as the half-cut lines 40 are closer to the upper end. This makes it easy to gather the half-cut lines 40 of the inclined portion 34 at the central straight portion 35. In addition, the first half-cut portion 31 can be configured so that the end of the first sheet 21 protrudes in a trapezoidal shape after the packaging bag 10 is opened. Therefore, after the packaging bag 10 is opened, it is easy to open the bag portion 24 of the packaging bag 10 by pinching the end of the first sheet 21.

[0113] (3) By setting the ratio of the height Hi to the length Li of the inclined portion 34 to 0.3 or less, the inclination angle of the inclined portion 34 is prevented from becoming too steep, thereby improving the ability of the tear line to follow the inclined portion 34. Furthermore, by setting the ratio of the height Hi to the length Li of the inclined portion 34 to 0.12 or more, the length Li of the inclined portion 34 does not become too large, thereby improving the ability of the tear line to follow the inclined portion 34.

[0114] (4) If the width of the half-cut line 40 in the central straight portion 35 is 200 μm or more and 400 μm or less, the width of the half-cut line 40 is sufficiently ensured, so that deviation of the tear line from the half-cut line 40 is appropriately suppressed.

[0115] (5) The first half-cut portion 31 includes an end straight portion 33 at an end of the first half-cut portion 31, and the end straight portion 33 has linear half-cut lines 40 that are connected to the half-cut lines 40 of the inclined portion 34 one by one. With this configuration, even if there is a shift in the formation position of the outer edge of the packaging bag 10 or the formation position of the opening starting point 26, the position where the tear line formation starts is prevented from shifting from the first half-cut portion 31.

[0116] (6) Since the entire straight end portion 33 is located in the seal portion 23, which is harder than the bag portion 24, the tear line tends to follow the first half-cut portion 31 more stably at the transition point from the straight end portion 33 to the inclined portion 34.

[0117] (7) The height position of the end point T of the opening starting point 26 is included in the range where the end of the inclined portion 34 opposite the central straight portion 35 is located. This makes it possible to prevent the end point T from shifting from the first half-cut portion 31 even if a shift occurs in the formation position of the opening starting point 26, and makes it easier for the tear line to follow the first half-cut portion 31 near the inclined portion 34.

[0118] (8) Because the second half-cut portion 32 is formed by the straight cut line 44, which is a half-cut line that extends linearly along the length direction, the second half-cut portion 32 is simply configured and easily formed. The height position of the straight cut line 44 is included in the range where the end of the inclined portion 34 opposite the central straight portion 35 is located. As a result, even if the first half-cut portion 31 and the second half-cut portion 32 are misaligned, the straight cut line 44 is positioned below the half-cut line 40 of the central straight portion 35 in the height direction, and a step is formed between the upper edge of the first sheet 21 and the upper edge of the second sheet 22 after opening. Therefore, an opener can easily grasp the vicinity of the upper edge of the first sheet 21, making it easy to open the bag portion 24.

[0119] (9) In the cross section of the first sheet 21, protrusions 45 that protrude from the surface 50S of the base material layer 50 are located on both sides of the half-cut line 40 in the width direction. This makes it difficult for the tearing of the first sheet 21 that progresses along the half-cut line 40 to deviate from the half-cut line 40.

[0120] (10) The intermediate layer 51 is a resin film having a metal vapor deposition film, which improves gas barrier properties and reduces the manufacturing costs of the packaging bag 10 compared to when the intermediate layer 51 is a metal foil. Furthermore, the width of the half-cut line 40 is widened in the central straight portion 35 to improve the followability of the tear line. Therefore, even if the intermediate layer 51 is easily destroyed by laser irradiation and there is a limit to the depth of the cut that can be formed, the followability of the tear line to the first half-cut portion 31 can be suitably improved.

[0121] [Variations] The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0122] The number of half-cut lines 40 that the end straight portion 33 and the inclined portion 34 have may be plural, for example, two or four. The inclination angles of the multiple half-cut lines 40 in the inclined portion 34 may be different from those in the above embodiment. For example, the multiple half-cut lines 40 may include half-cut lines 40 with the same inclination angle.

[0123] At the central straight portion 35, two or more half-cut lines 40 in the inclined portion 34 need only be converged, and not all half-cut lines 40 in the inclined portion 34 need to be converged. Furthermore, the method of forming the half-cut lines 40 in the first half-cut portion 31 is not limited as long as the half-cut lines 40 in the inclined portion 34 converge at the central straight portion 35 and the width of the half-cut lines 40 is increased at the central straight portion 35. For example, in the above embodiment, the half-cut lines 40 in the central straight portion 35 are formed by multiple laser irradiations subsequent to the formation of the half-cut lines 40 in the inclined portion 34. However, the half-cut lines 40 in the central straight portion 35 may be formed by a single laser irradiation by increasing the diameter of the laser beam larger than that of the inclined portion 34.

[0124] The first half-cut portion 31 only needs to include the inclined portion 34 and the central straight portion 35, and does not necessarily need to include the end straight portion 33. The shape of the half-cut line in the second half-cut portion 32 may be different from that in the above embodiment. For example, the half-cut line in the second half-cut portion 32 may be curved, or may have the same shape as the first half-cut portion 31. If the half-cut line in the second half-cut portion 32 is configured so as not to overlap at least a part of the half-cut line 40 in the central straight portion 35 in the first half-cut portion 31, a misalignment will occur at the ends of the first sheet 21 and the second sheet 22 in the packaging bag 10 after opening, making it easy to open the bag portion 24. [Explanation of symbols]

[0125] 10...Packaging bag 21...1st seat 22...Second seat 23...Seal part 24…Fukuro part 25...Resealing member 26...Opening starting point 30…Opening guidance part 31...First half cut section 32...Second half cut section 40, 41a-41c, 42a-42c, 43, 44...Half cut lines 45...Protuberance 50...Base material layer 51...Middle class 52...Sealant layer

Claims

1. A packaging bag comprising a first sheet and a second sheet facing each other, the packaging bag has a sealed portion at a peripheral edge of the packaging bag where the first sheet and the second sheet are joined together, the first sheet has a first half-cut portion extending from the seal portion across the packaging bag, the first half-cut portion being composed of a half-cut line which is a portion where a cut extending linearly with a depth that does not penetrate the first sheet is located; The direction in which the first half-cut portion extends is a length direction, and the direction perpendicular to the length direction along the surface of the first sheet is a height direction, the first half-cut portion includes a central straight portion located in an area including a center of the first half-cut portion in the length direction, and an inclined portion connected to the central straight portion on the side where the seal portion is located relative to the central straight portion, the inclined portion has inclined cut lines that are the half-cut lines extending in a direction inclined with respect to the length direction, and a ratio of a length of the inclined portion in the height direction to a length of the inclined portion in the length direction is 0.3 or less; The central straight section includes the half-cut line extending linearly along the length direction, and the half-cut line is formed by collecting and joining a plurality of the inclined cut lines. packaging bag.

2. Of both end portions of the packaging bag in the height direction, an end portion closer to the first half-cut portion is an upper end portion of the packaging bag, The oblique cut lines are inclined toward the central linear portion so as to approach the upper end portion, and the inclination angles of the plurality of oblique cut lines with respect to the length direction become smaller as the oblique cut lines are closer to the upper end portion. The packaging bag according to claim 1.

3. The ratio of the length of the inclined portion in the height direction to the length of the inclined portion in the length direction is 0.12 or more. The packaging bag according to claim 1.

4. The width of the half-cut line in the central straight line portion is greater than the width of the oblique cut line and is 200 μm or more and 400 μm or less. The packaging bag according to claim 1.

5. the first half-cut portion includes an end linear portion at an end of the first half-cut portion in the length direction, the end straight portion is connected to the inclined portion on the opposite side of the central straight portion with respect to the inclined portion in the length direction, The end straight portion includes a plurality of half-cut lines extending linearly along the length direction, the half-cut lines being connected to the respective inclined cut lines one by one. The packaging bag according to claim 1.

6. The entire straight end portion is located in the seal portion. The packaging bag according to claim 5.

7. The packaging bag has an opening starting point portion that functions as a starting point for opening the packaging bag, The opening starting point extends from the outer edge of the packaging bag into the sealed portion, The point of the opening starting point portion that is farthest from the outer edge of the packaging bag in the length direction is the end point of the opening starting point portion, In the height direction, the position of the end point is included in a range in which an end of the inclined portion opposite to the central straight portion is located. The packaging bag according to claim 1.

8. the second sheet includes a second half-cut portion extending from the sealed portion across the packaging bag in a direction coinciding with the first half-cut portion, the second half-cut portion is formed by a half-cut line, which is a portion where a cut extending linearly is located and has a depth that does not penetrate through the second sheet, The half-cut line of the second half-cut portion extends linearly along the extending direction of the second half-cut portion. The packaging bag according to claim 1.

9. The position of the half-cut line of the second half-cut portion in the direction along the height direction is The end of the inclined portion opposite to the central straight portion is included in the range in the height direction. The packaging bag according to claim 8.

10. the first sheet includes a base layer, a sealant layer, and an intermediate layer located between the base layer and the sealant layer; the cut line of the half-cut line is in at least a part of the base material layer in the thickness direction of the first sheet, the sealant layer is joined to the second sheet at the sealed portion; The intermediate layer is a resin film having a metal vapor deposition film. The packaging bag according to claim 1.

11. the first sheet includes a base layer, a sealant layer, and an intermediate layer located between the base layer and the sealant layer; the cut line of the half-cut line is in at least a part of the base material layer in the thickness direction of the first sheet, the sealant layer is joined to the second sheet at the sealed portion; In a cross section of the first sheet, protruding portions that are raised relative to the surface of the base material layer are located on both sides of the half-cut line in the width direction. The packaging bag according to claim 1.

12. The inclined portion has three or more inclined cut lines. The packaging bag according to claim 1.

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