Manufacturing method of sheet packaging bag

Abstract

To provide a manufacturing method of a packaging bag which can extend a service life of a blade of a die-cut roll while suppressing advance of contact friction of the blade of the die-cut roll.SOLUTION: A manufacturing method of a sheet packaging bag having a tearing cutting line for forming a sheet take-out port includes a cutting line forming process in which a pair of thin and long tearing cutting lines 50 in a longitudinal direction is formed on a base material 100 of the packaging bag by repeating a contact state and a non-contact state of a blade 400 of a die-cut roll 200 and an anvil roll 300. The cutting line forming process includes an alternate cutting line forming process in which the blade of the die-cut roll and the anvil roll are brought into contact in the other tearing cutting line when the blade of the die-cut roll and the anvil roll are not brought into contact in one tearing cutting line, and the blade of the die-cut roll and the anvil roll are brought into contact in one tearing cutting line when the blade of the die-cut roll and the anvil roll are not brought into contact in the other tearing cutting line.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a sheet packaging bag. [Background technology]

[0002] Sheet packaging bags containing sheets such as paper towels and tissue paper are distributed and used in a state where multiple sheets are contained in a packaging bag made of resin film (for example, Patent Document 1). In recent years, from the viewpoint of reducing environmental impacts such as global warming due to CO2 emissions and marine pollution by microplastics, there has been an active movement to switch from resin packaging bags to paper packaging bags and reduce the amount of resin used in packaging bags.

[0003] However, packaging bags made from resin films are still in high demand due to their high flexibility and light weight.

[0004] The film-wrapped tissue paper disclosed in Patent Document 1 has perforations for opening formed on the top surface, and a slit-shaped dispensing opening is formed by opening the perforations. To form the slit-shaped dispensing opening, a pair of perforations for opening is formed in the longitudinal direction. The perforations are formed by alternating ties, where the base materials constituting the packaging bag are connected, with cuts, where the base materials are cut. When looking from the tie of one perforation to the other perforation in the width direction perpendicular to the longitudinal direction, the tie and the cut of the pair of perforations are the same. When looking from the cut of one perforation to the other perforation, a cut is also formed. That is, in the elongated longitudinal opening perforations, the tie faces the tie and the slit faces the slit in the width direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6709722 Summary of the Invention [Problem to be solved by the invention]

[0006] When forming perforations (tear lines) for opening to form elongated slits using a rotary die-cutting device, the substrate of the packaging bag is inserted between the blades formed on the circumferential surface of the die-cutting roll and the anvil roll. When the blades of the die-cutting roll and the anvil roll are in contact, a cut is formed in the substrate. When a gap is formed between the part of the circumferential surface of the die-cutting roll where no blades are formed and the anvil roll, a tie is formed in the substrate. In this case, when a pair of tear lines is formed in the direction of travel (MD) of the substrate, the blades of the pair of die-cutting rolls and the anvil roll come into contact at the same time when the cut is formed, and when the tie is formed, a gap is formed between the die-cutting roll and the anvil roll at the same time.

[0007] For this reason, when forming a pair (two) of tearing score lines, contact and non-contact states occur periodically at two points (two points), which increases mechanical vibration, accelerates wear on the die-cut roll blades caused by the contact, and tends to shorten the life of the die-cut roll blades.

[0008] An object of the embodiment is to provide a method for manufacturing packaging bags that can suppress the progression of contact friction of the blades of the die-cut roll in a rotary die-cut device and extend the life of the blades of the die-cut roll. [Means for solving the problem]

[0009] A first embodiment of the disclosed invention is a method for manufacturing a sheet packaging bag that contains multiple stacked sheets, has a top surface, and has tearing score lines that, when torn, form an elongated sheet removal opening whose longitudinal length is longer than its maximum width. The method includes a score line forming process in which a pair of tearing score lines in the longitudinal direction of the elongated shape are formed in the base material of the packaging bag by repeatedly moving the blades of a pair of die-cut rolls and anvil roll between contact and non-contact states, and the score line forming process includes an alternating score line forming process in which, when the blades of the die-cut roll and the anvil roll are non-contact at one tearing score line, the blades of the die-cut roll and the anvil roll are in contact at the other tearing score line, and when the blades of the die-cut roll and the anvil roll are non-contact at the other tearing score line, the blades of the die-cut roll and the anvil roll are in contact at one tearing score line.

[0010] According to the first embodiment, when the die-cut roll blade and the anvil roll are not in contact with each other at one tearing score line, the die-cut roll blade and the anvil roll are in contact with each other at the other tearing score line, and when the die-cut roll blade and the anvil roll are not in contact with each other at the other tearing score line, the die-cut roll blade and the anvil roll are in contact with each other at one tearing score line.

[0011] Therefore, the blade and the anvil roll do not start contacting each other at two points simultaneously, but instead start contacting each other alternately, which may include cases where contact occurs at only one point. This reduces the impact caused by contact and reduces mechanical vibration, thereby suppressing the progression of contact wear. As a result, the life of the die-cut roll blades can be extended.

[0012] A second embodiment of the disclosed invention is a method for manufacturing a sheet packaging bag, in which the alternating score line forming process includes a case in which the widthwise length of a pair of longitudinal tearing score lines increases or decreases.

[0013] When paper towels or tissues stored in plastic sheet packaging bags are dispensed using a pop-up method, an opening that bulges out from the center of the dispense opening toward the ends may be formed to prevent the paper towels or tissues from falling out after dispensing (Fig. 1 and Fig. 2).In such a region where the width increases or decreases from the center of the dispense opening toward the end of the elongated shape, the direction of the applied tearing force and the tearing score line form an angle.

[0014] Even when such an outlet is formed, when the blade of the die-cut roll and the anvil roll are not in contact at one tearing score line, the blade of the die-cut roll and the anvil roll are in contact at the other tearing score line, and when the blade of the die-cut roll and the anvil roll are not in contact at the other tearing score line, the blade of the die-cut roll and the anvil roll are in contact at one tearing score line.

[0015] Therefore, the progress of contact wear can be suppressed, and the life of the blades of the die-cut roll can be extended.

[0016] A third embodiment of the disclosed invention is a method for manufacturing a sheet packaging bag, in which the alternating score line forming process includes a case where the widthwise length of the pair of longitudinal tearing score lines is constant.

[0017] In the third embodiment, when the die-cut roll blade and the anvil roll are not in contact with each other at one tearing score line, the die-cut roll blade and the anvil roll are in contact with each other at the other tearing score line, and when the die-cut roll blade and the anvil roll are not in contact with each other at the other tearing score line, the die-cut roll blade and the anvil roll are in contact with each other at one tearing score line.

[0018] Therefore, the progress of contact wear can be suppressed, and the life of the blades of the die-cut roll can be extended.

[0019] A fourth embodiment of the disclosed invention is a method for producing a sheet packaging bag, wherein the substrate includes any one of a plastic film substrate, a paper substrate, and a laminate substrate of paper and plastic.

[0020] The base material for packaging bags may be a flexible plastic film, a tissue carton using a conventionally used thick paper base material (cardboard), or a laminate base material of a paper base material and a plastic film. Even when such a base material is used, when the die-cut roll blade and the anvil roll are not in contact with each other at one tearing score line, they are in contact with each other at the other tearing score line, and when the die-cut roll blade and the anvil roll are not in contact with each other at the other tearing score line, they are in contact with each other at one tearing score line.

[0021] Therefore, the progress of contact wear can be suppressed, and the life of the blades of the die-cut roll can be extended. [Effects of the Invention]

[0022] According to one aspect of the disclosed invention, the progression of contact friction of the blades of the die-cutting roll in a rotary die-cutting device can be suppressed, thereby extending the life of the blades of the die-cutting roll. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a perspective view illustrating a sheet packaging bag. [Figure 2] FIG. 2 is a perspective view illustrating a usage mode of the sheet packaging bag. [Figure 3] FIG. 1 is a diagram illustrating an outline of a rotary die-cutting device for forming a tearing score line where a tie portion and a cut portion face each other, and explaining the positional relationship between the blades of the die-cutting roll and the anvil roll. [Figure 4]10A and 10B are diagrams illustrating an example of a tearing score line for forming an outlet, manufactured by a manufacturing method according to an embodiment. [Figure 5] 5 is an explanatory diagram of the relationship between ties and cuts at a portion where the widthwise length of the splitting score line in FIG. 4 increases (widened portion) and a portion where the width is constant (narrowed portion). [Figure 6] FIG. 6 is an explanatory diagram of the same location as FIG. 5, where ties face each other and cut portions face each other. DETAILED DESCRIPTION OF THE INVENTION

[0024] <Sheet packaging bag> Before describing the manufacturing method of the sheet packaging bag according to the embodiment of the present invention, the sheet packaging bag will be described with reference to the drawings. In each drawing, common parts are given the same reference numerals and their description may be omitted. In each drawing, the scale of each part may differ from the actual scale. In each drawing, the longitudinal direction of the packaging bag is the X direction, the width direction is the Y direction, and the height direction is the Z direction.

[0025] Fig. 1 is a perspective view illustrating a sheet packaging bag according to an embodiment, and Fig. 2 is a perspective view illustrating a usage mode of the sheet packaging bag.

[0026] As shown in FIG. 1, the sheet packaging bag 1 has a substantially rectangular parallelepiped shape and contains multiple stacked sheets (a sheet stack). When the sheet stack is stored inside, it has two short sides (end faces) 4A, two long sides 4B, a top (upper face) 4C, and a bottom (lower face) 4D. The packaging bag shown in FIG. 1 shows an embodiment of gusset packaging in which the two short sides (end faces) 4A are the sealing faces, and is a gusseted pillow package. Note that in this embodiment, the sealing face is not limited to gusset packaging, and can also be in the form of caramel packaging (overwrap packaging) in which the short sides have overlapping flaps that are fused together. In FIG. 1, 4X denotes the overlapping portion that is rolled into a cylindrical shape when gusset packaging is performed with plastic film, and is usually joined by heat sealing.

[0027] As shown in FIG. 2, the stored sheet stack can be pulled out one set at a time of sheets (sanitary thin paper) 2 through an outlet 6 formed on the top surface 4C of the sheet packaging bag 1.

[0028] The form of the sheet stack is not particularly limited, and examples thereof include a stack of sheets in a folded state, a stack of sheets in a folded state and stacked alternately (a so-called pop-up sheet stack), and a stack of multiple sheets simply stacked.

[0029] The dimensions of the sheet laminate can be about 150 to 250 mm in the longitudinal direction (X direction) of the packaging bag 10, about 70 to 150 mm in the width direction (Y direction) perpendicular to the longitudinal direction (X direction) of the packaging bag 10, and about 20 to 100 mm in the height direction (Z direction). Such a tissue paper laminate can be produced, for example, by a rotary or multi-stand interfolder.

[0030] The density of the sheet laminate is 0.09 g / cm 3 More than 0.50g / cm 3 or less, preferably 0.13 g / cm 3 More than 0.40g / cm 3 or less, more preferably 0.15 g / cm 3 More than 0.30g / cm 3 The density of the sheet laminate is measured in accordance with the provisions of JIS P 8118 (2014).

[0031] The form of the sheet laminate is not particularly limited, and it can be applied to, for example, sanitary thin papers such as paper towels, kitchen paper, tissue paper, toilet paper, etc. These sanitary thin papers also include sanitary thin papers containing moisturizing ingredients (for example, lotion tissue, etc.).

[0032] The use of the sheet laminate is not particularly limited, and the sheet laminate can be used for industrial, household, and portable purposes. Among these, household and portable paper towels are preferably used as the sheet laminate in this embodiment.

[0033] The number of plies of the sheets in the laminate is not particularly limited, but can be 1 or more, and is preferably 1 or 2. The shape of the sheet 2 is not particularly limited, but it is preferable that the outline shape of the 2-ply sheet when folded is quadrangular (rectangle, square, etc.).

[0034] The material of the sheet is not particularly limited, but may be, for example, a sheet of paper, nonwoven fabric, or cloth, and is preferably paper (paper sheet). When the sheet is paper, base paper containing pulp as the main raw material is used. The pulp composition may be any known composition for paper sheets. For example, the pulp content may be 50% by mass or more, preferably 90% by mass or more, and more preferably 100% by mass.

[0035] The pulp composition of the sheet (paper sheet) is not particularly limited. For example, softwood pulp such as NBKP (softwood kraft pulp) or NUKP (softwood unbleached pulp) and hardwood pulp such as LBKP (hardwood kraft pulp) or LUKP (hardwood unbleached pulp) can be used in any ratio.

[0036] The ratio of hardwood pulp to softwood pulp in the sheet (paper sheet) is not limited, but is preferably 10:90 to 80:20, and more preferably a pulp composition in which the ratio of softwood pulp to hardwood pulp is higher. Furthermore, recycled paper pulp may be used as the pulp contained in the sheet S (paper sheet).

[0037] The basis weight of the sheet is not particularly limited, but in the case of paper, it is 5 g / m depending on the number of plies. 2 More than 80g / m 2 and preferably 10 g / m 2 More than 60g / m 2 Less than 10 g / m, more preferably 2 More than 45g / m 2 In the case of nonwoven fabric, the density is 20 g / m 2More than 100g / m 2 The following is desirable: Basis weight is measured in accordance with the provisions of JIS P 8124 (2011).

[0038] The thickness of the sheet is not particularly limited, and can be the paper thickness measured under the environment of JIS P 8111 (1998). For example, when the sheet S is paper, the thickness is 50 μm or more and 600 μm or less, preferably 60 μm or more and 500 μm or less, and more preferably 130 μm or more and 400 μm or less per two plies.

[0039] The sheet may also be embossed, which can be carried out by a known embossing method.

[0040] The shape of the sheet packaging bag 1 is not particularly limited. In this embodiment, the bag has a top surface 4C, a bottom surface 4D, two long side surfaces 4B, and two short side surfaces (edge ​​surfaces) 4A. In the packaging bag 1 of this embodiment, the top surface 4C and the bottom surface 4D face each other in the vertical direction, the long side surfaces 4B face each other in the width direction (Y direction), and the short side surfaces 4A face each other in the longitudinal direction (X direction). The short side surfaces 4A are continuous with all of the top surface 4C, bottom surface 4D, and side surfaces 4B (FIGS. 1 and 4).

[0041] The dimensions of the sheet packaging bag 1 are not particularly limited. For example, the length in the longitudinal direction (X direction) of the packaging bag 1 can be about 150 to 250 mm, the width in the width direction (Y direction) perpendicular to the longitudinal direction (X direction) of the packaging bag 1 can be about 70 to 150 mm, and the height in the height direction can be about 20 to 100 mm (Fig. 1). The dimensions of the sheet packaging bag 1 refer to the dimensions when the sheet laminate 2 is contained in the packaging bag 1.

[0042] A tearing score line 50 for forming an elongated outlet 6 (FIG. 2) extending in the longitudinal direction (X direction) is formed on the top surface 4C of the sheet packaging bag 1. The area surrounded by the tearing score line 50 becomes the outlet forming portion 5, and the outlet 6 is formed by removing the outlet forming portion 5.

[0043] An embodiment of the present invention is a method for manufacturing a sheet packaging bag, which includes the step of forming the tearing score lines.

[0044] <Method of forming a score line for cleavage> Rotary die-cutting machines are often used to form score lines or embossed patterns on resin films and nonwovens used in sheet packaging bags, nursing and baby diapers, sanitary napkins, etc.

[0045] In a rotary die-cutting device, a die-cutting blade for processing is provided on the peripheral surface of a die-cutting roll, and cutting and embossing of a substrate are continuously performed between the rotating die-cutting roll and anvil roll.

[0046] To form a tearing score, a blade for forming the cut is provided on the periphery of the die-cut roll, and a substrate such as a resin film or paper is fed between the die-cut roll and the anvil roll. When the blade of the die-cut roll comes into contact with the surface of the anvil roll as the two rolls rotate, a cut is made in the substrate. When a gap is created between the periphery of the die-cut roll and the anvil roll, the substrate is not cut, and a tie is formed.

[0047] The die-cut roll has blades on its peripheral surface at positions corresponding to the cut score lines so that predetermined score lines are formed in the substrate by the rotation of the roll, and the rotation of the die-cut roll and the anvil roll continuously forms score lines for cleaving in a predetermined shape. The substrate with the score lines for cleaving formed is sent to the next processing step.

[0048] In addition, cases where the blades on the circumferential surface of the die-cut roll and the anvil roll do not come into contact and a gap is formed between them include cases where parts on the circumferential surface of the die-cut roll with blades and parts without blades are arranged alternately, as well as the following cases.

[0049] Examples include cases where tall blades and shorter blades are arranged alternately, or cases where blades and protruding bodies that are not formed with blades but are slightly shorter in height than the blades are arranged alternately.

[0050] Figure 3(a) is a schematic diagram of an example of a rotary die-cutting device, and Figure 3(b) is a diagram showing the process of forming score lines using a die-cutting roll and anvil roll.

[0051] In FIG. 3(b), a blade 400 is provided on the peripheral surface of the die-cut roll 200 so that, for example, when the peripheral surface is unfolded, the tearing score line 50 shown in FIG. 1 is formed. When the die-cut roll 200 and the anvil roll 300 rotate, the blade 400 of the die-cut roll comes into contact with the anvil roll, forming a cut in the substrate at a position corresponding to the contact position. If the die-cut roll 200 does not have a blade on its peripheral surface and comes into contact with the anvil roll 300 or a slight gap is formed, the substrate is not cut at that position, resulting in a tie (uncut). The direction in which the substrate is fed by the die-cut roll and the anvil roll is the MD (machine direction), which indicates the flow direction of the substrate and processed product. In this embodiment, the MD direction corresponds to the longitudinal direction (X direction) of the sheet packaging bag.

[0052] 1 is formed on, for example, the resin film substrate 100, two score lines are aligned in the Y direction and extend in the X direction (MD direction). These two score lines are formed simultaneously by the die-cut roll and the anvil roll, and therefore a pair of rows of blades are formed in the MD direction on the peripheral surface of the die-cut roll.

[0053] In this case, the relationship between the ties and cuts on the two tearing score lines facing each other in the Y direction has traditionally been such that a tie is formed on one score line as seen from the other tie, and a cut is formed on the other score line as seen from the other cut (Figure 6). For this reason, a pair of blades on the circumferential surface of the die-cut roll simultaneously come into contact with the anvil roll on the two score lines to form cuts. If a gap is formed between the blades on the circumferential surface of the die-cut roll and the anvil roll, no cuts are formed and ties are simultaneously formed.

[0054] When the die-cut roll blades and the anvil roll make contact simultaneously and periodically in two places, the impact of the contact becomes greater. This generates mechanical vibrations in the die-cut roll device, increasing the contact friction of the blades. As a result, the blades tend to have a shorter lifespan. Furthermore, as the rotation speed of the die-cut rolls increases in order to increase production volume per hour, the contact friction progresses more quickly, further shortening the blades' lifespan.

[0055] In this embodiment, when forming a pair of tearing score lines, when the blade of the die-cut roll and the anvil roll are not in contact at one tearing score line, the blade of the die-cut roll and the anvil roll are in contact at the other tearing score line, and when the blade of the die-cut roll and the anvil roll are not in contact at the other tearing score line, the blade of the die-cut roll and the anvil roll are in contact at one tearing score line.

[0056] Therefore, the blade and the anvil roll do not start contacting each other at two points simultaneously, but instead start contacting each other alternately, and there are cases where contact occurs at only one point. This reduces the impact caused by contact and reduces mechanical vibration, thereby suppressing the progression of contact wear. As a result, the life of the die-cut roll blades can be extended.

[0057] FIG. 4 shows an example of a cleavage score line produced by the manufacturing method of this embodiment.

[0058] 4 has narrow portions 51 in which the two score lines are narrow and have a constant width (parallel), wide portions 52 on both ends of the narrow portions 51 whose widthwise length increases toward the ends, and curved convex portions 53 that are continuous with the wide portions 52 and bulge outward in the X direction. The wide portions 52 and curved convex portions 53 form a gourd-shaped score line 50 that is narrow in the center and has bulging portions on both ends.

[0059] The widened portion is an example of a region whose width increases from the center toward each end of the elongated shape, and the narrowed portion is an example of a region whose width is constant.

[0060] 4, the tearing score line 50 is made up of perforations in all of the narrow portion, the wide portion, and the curved bulge portion, forming a circular tearing score line. The ratio of ties 50U to cuts 50C in the tearing score line 50 (perforations) is arbitrary, but can be, for example, 1:1 to 1:5, preferably 1:2 to 1:4, and more preferably 1:2.5 to 1:3.5.

[0061] The ratio of ties 50U to cuts 50C in the widened portion is preferably 1:4 or more, and when the rate of increase in the widthwise length of the widened portion is large (when the inclination angle from the longitudinal direction is large), it is preferable to set it to, for example, 1:8 or more.

[0062] As shown in Fig. 4, the tearing score lines 50 are arranged in the widened portion 52 so that a tie is located on one score line in the width direction (Y direction) perpendicular to the longitudinal direction (X direction) and a cut is located on the other score line opposite the tie. In other words, when a tie is located on one score line of a pair of score lines, a cut is located on the other score line in the perpendicular direction. Conversely, when a tie is located on the other score line, a cut is located on one score line.

[0063] The tie position on one score line and the cut position on the other score line preferably face each other such that the tie position is approximately in the center of the length of the cut. This relationship between the tie and the cut is such that, in two rows of blades arranged on the periphery of the die-cut roll, the gap forming the tie in one row is positioned opposite the approximate center of the length of the blade in the opposing blade row. By positioning the gap opposite the approximate center of the length of the blade in the opposing blade row, contact between the blade and the anvil roll is repeated at regular intervals, which is preferable as it reduces fluctuations in friction caused by contact.

[0064] Even if the gap is shifted in the forward / backward direction of the rotation from the center of the opposing blades in the longitudinal direction, the intervals at which contact begins will be slightly irregular rather than regular, but the blades and the anvil roll will begin to contact each other alternately, and contact may occur at only one point. Therefore, even if there is such a shift in the longitudinal direction, the impact caused by contact will be small, and the mechanical vibration of the device can be reduced.

[0065] When arranging the tie and cut on a curved line such as the widened portion 52, the tie and cut should be positioned facing each other when the curved tearing score line is projected onto the longitudinal direction.

[0066] Fig. 5 shows (a) the widened portion 52 of the tearing score line 50 produced in this embodiment shown in Fig. 4, and (b) the score line of the narrowed portion 51. Fig. 6 shows a conventional tearing score line in which ties face ties and cuts face cuts, corresponding to Fig. 5.

[0067] Table 1 compares the number of shots required to replace the blade between Example 1, in which the widening section 52 shown in FIG. 5(a) is arranged so that the tie faces the cut, as in this embodiment, and Comparative Example 1, in which the widening section 52 is arranged so that the tie faces the tie and the cut faces the cut, as in the conventional embodiment, as shown in FIG. 6(a). The substrate used was polyethylene (PE). It should be noted that a laminate substrate of polyethylene terephthalate (PET) and PP may also be used, with PE and polypropylene (PP) as the main substrates.

[0068] [Table 1]

[0069] The number of shots required to change the blade, as shown in Table 1, is more than double when the cut and tie are asymmetric, with one tie facing the cut on the other side and the other tie facing the cut on the other side, compared to when the symmetrical tie and cut are facing each other. This shows that an asymmetric arrangement suppresses the generation of mechanical vibration and contact friction more than a symmetric arrangement, and can extend the life (durability) of the blade.

[0070] In addition, suppressing the occurrence of mechanical vibrations not only extends the life of the blades, but also suppresses the occurrence of minute vibrations in the entire die-cut roll device, thereby increasing the durability of the device itself.

[0071] Although the embodiments of the present invention have been described above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the invention described in the claims. [Explanation of symbols]

[0072] 1 sheet packaging bag 2. Sheet laminate (hygienic thin paper) 3C top 6 Sheet outlet 50 Cut line for tearing (perforation) 50C cut 50U Thailand 51 Narrow section (length in width direction is constant) 52 Widened section (length increases in the width direction) 100 Base material 200 die cut rolls 300 Anvil Roll 400 Die-cut roll blade

Claims

1. A method for manufacturing a sheet packaging bag that contains a plurality of stacked sheets, has a tearing score line on the top surface, and forms an elongated sheet removal opening that is longer in the longitudinal direction than the maximum length in the width direction when torn, a score line forming step in which a pair of tearing score lines in the longitudinal direction of the elongated shape are formed in the base material of the packaging bag by repeatedly bringing a pair of die-cut roll blades and an anvil roll provided in a rotary die-cut device into contact with and out of contact with each other; The method for manufacturing a sheet packaging bag includes an alternating score line forming process, in which when the die-cut roll blade and the anvil roll are not in contact with each other at one tearing score line, the die-cut roll blade and the anvil roll are in contact with each other at the other tearing score line, and when the die-cut roll blade and the anvil roll are not in contact with each other at the other tearing score line, the die-cut roll blade and the anvil roll are in contact with each other at one tearing score line.

2. The method for manufacturing a sheet packaging bag according to claim 1 , wherein the alternating score line forming step includes a step of increasing or decreasing the widthwise length of the pair of longitudinal tear score lines.

3. The method for manufacturing a sheet packaging bag according to claim 1 or 2, wherein the alternating score line forming step includes a case where the pair of longitudinal tear score lines have a constant length in the width direction.

4. The method for manufacturing a sheet packaging bag according to claim 1 , wherein the substrate includes any one of a plastic film substrate, a paper substrate, and a laminate substrate of paper and plastic.

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