Packaging bag and method for manufacturing a packaging bag

Abstract

To provide a method for manufacturing a packaging bag that has sufficient tear resistance while allowing the contents to be removed, and to provide a packaging bag. [Solution] A method for manufacturing a packaging bag, comprising a step of forming an opening line on the packaging bag to assist in opening, wherein the packaging bag consists of opposing surface laminates and back laminates, the packaging bag has a sealing portion that seals the peripheral edges of the surface laminates and back laminates, and a storage portion that contains contents, the surface laminates and back laminates each have a laminated structure comprising a base layer, an adhesive layer, and a sealant layer in that order, the base layer is made of polyethylene film, and the sealant layer contains polyethylene resin, the method for manufacturing a packaging bag comprising irradiating the packaging bag with laser light to volatilize a part of the surface laminates and back laminates to form a linear void that will become an opening line, and the packaging bag after the process has a fused portion where the sealant layers of the surface laminates and back laminates are fused together at a position overlapping with the linear void, the width of the fused portion being 5 to 100 μm.

Description

[Technical Field]

[0001] This disclosure relates to packaging bags and methods for manufacturing packaging bags. [Background technology]

[0002] Packaging bags for cosmetics, shampoos, conditioners, body soaps, and laundry detergents are known. Such packaging bags are required to be easy to open in order to remove the contents.

[0003] Incidentally, packaging bags formed using laminated films made of different materials are not easy to separate by material after being collected as waste. Therefore, in order to improve their recyclability, research is underway on packaging materials made from a single material, so-called monomaterial packaging.

[0004] Patent Document 1 discloses a method for manufacturing a pouch, comprising the steps of: preparing a predetermined laminate including an inner and outer surface; forming a seal portion by joining the inner surfaces of the laminates; and a laser step of forming a half-cut line by irradiating the laminate with a laser. Furthermore, Patent Document 1 discloses that a pouch can be obtained by cutting the laminate on which the half-cut line has been formed and then heat-sealing it. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-112322 [Overview of the project] [Problems that the invention aims to solve]

[0006] In the pouch manufacturing method disclosed in Patent Document 1, a pouch is obtained by bonding together laminates on which half-cut lines have been formed. The inventors' research has revealed that in this method, when the laminates are heat-sealed together with the laminates facing each other, the half-cut lines formed by laser irradiation on the front and back surfaces may be significantly misaligned.

[0007] The inventors investigated forming an opening line to assist in opening a packaging bag having a sealing portion that seals the periphery of the surface laminate and the back laminate, and a storage portion that contains the contents. They also selected a polyethylene resin as the material to realize a monomaterial packaging. Through investigation, it became clear that when laser light was irradiated from the surface and back of the packaging bag containing the polyethylene resin, the laminates transmitted the laser light without absorbing it, causing the laminates to fuse together strongly, making it difficult to remove the contents. In particular, the fusion became stronger when the surface laminate and the back laminate faced each other and the sealants were in close proximity.

[0008] This disclosure provides a method for manufacturing a packaging bag that has sufficient tearability while allowing the contents to be removed, and a packaging bag. [Means for solving the problem]

[0009] One aspect of this disclosure provides the following methods for manufacturing packaging bags and the packaging bags themselves. [1] The process includes forming an opening line on the packaging bag to assist in opening it, The above packaging bag consists of opposing surface laminates and back laminates. The above packaging bag has a sealing portion that seals the peripheral edges of the surface laminate and the back laminate, and a storage portion for containing the contents. The above surface laminate and the above back surface laminate each have a laminated structure comprising a base layer, an adhesive layer, and a sealant layer in this order. The above-mentioned base layer is made of polyethylene film. The above sealant layer contains a polyethylene resin, In the above process, a laser beam is irradiated onto the packaging bag to volatilize a portion of the surface laminate and the back laminate, thereby forming a linear void that will serve as the opening line. The packaging bag after the above process has a fused portion where the sealant layer of the surface laminate and the back laminate are fused together at a position overlapping with the linear void. A method for manufacturing a packaging bag, wherein the width of the fused portion is 5 to 100 μm. [2] A packaging bag comprising opposing surface laminates and back laminates, It has a sealing portion that seals the peripheral edges of the surface laminate and the back laminate, a storage portion for containing contents, and an opening line to assist in opening, The above surface laminate and the above back surface laminate each have a laminated structure comprising a base layer, an adhesive layer, and a sealant layer in this order. The above-mentioned base layer is made of polyethylene film. The above sealant layer contains a polyethylene resin, The above surface laminate and the above back surface laminate each have a linear void between the base material layer and the sealant layer that will form the intended opening line. The packaging bag has a fused portion where the sealant layer of the surface laminate and the back laminate are fused together at a position overlapping with the linear void. A packaging bag in which the width of the fused portion is 5 to 100 μm. [3] The packaging bag according to [2], wherein the surface laminate and the back laminate each further comprises an intermediate layer made of polyethylene film between the base material layer and the sealant layer. [4] The packaging bag according to [2] or [3], wherein the surface laminate and the back laminate each further comprise a vapor-deposited layer. [5] The packaging bag described in any of [2] to [4], wherein the opening line is either a solid line or a dashed line. [6] The packaging bag described in any of [2] to [5], wherein the opening line is straight or curved. [7] A packaging bag according to any one of [2] to [6], wherein the above-mentioned opening line is formed on the seal portion. [8] The packaging bag according to any one of [2] to [7], wherein three unsealing lines are formed on each of the front laminate and the back laminate. [9] The packaging bag according to any one of [2] to [8], which comprises a chuck mechanism between the front laminate and the back laminate.

[10] The packaging bag according to any one of [2] to [9], which is a three-sided bag.

[11] The packaging bag is a self-standing packaging bag formed by heat-sealing a bottom tape and a pair of main body parts, wherein the pair of main body parts are composed of the front laminate and the back laminate, and the packaging bag according to any one of [2] to [8].

[12] The packaging bag according to any one of [2] to

[11] , wherein the content of the polyethylene-based resin is 90% by mass or more based on the total amount of the packaging bag. [Advantages of the Invention]

[0010] According to the present disclosure, there are provided a method for manufacturing a packaging bag and a packaging bag that have sufficient tearability and enable the contents to be taken out. [Brief Description of the Drawings]

[0011] [Figure 1] FIG. 1 is a front view schematically showing a packaging bag according to the first embodiment. [Figure 2] FIG. 2 is a perspective view schematically showing a pair of main body parts and a bottom tape constituting the packaging bag shown in FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view schematically showing the structure of the packaging bag shown in FIG. 1. [Figure 4] FIG. 4 is a plan view showing an enlarged view of the vicinity S1 of the take-out opening 21 of the packaging bag shown in FIG. 1. [Figure 5] FIG. 5 is a plan view showing an enlarged view of the vicinity S2 of the unsealing line shown in FIG. 4. [Figure 6] FIG. 6 is an end view taken along the imaginary line A-A in FIG. 5. [Figure 7] FIG. 7 is a front view schematically showing a packaging bag according to the second embodiment. [Figure 8] Figure 8(a) is a schematic front view showing an example of the first packaging bag. Figure 8(b) is a schematic front view showing an example of the second packaging bag. [Figure 9] Figure 9(a) is an end view along the dashed line BB in Figure 8(a). Figure 9(b) is a schematic end view showing the irradiation of the first packaging bag with laser light along the dashed line BB in Figure 8(a). Figure 9(c) is an end view along the dashed line CC in Figure 8(b). [Modes for carrying out the invention]

[0012] This document describes the packaging bags related to this disclosure.

[0013] <Packaging bag> A standing pouch (self-standing packaging bag) will be described as a packaging bag according to the first embodiment of this disclosure. The standing pouch is used as a refill pouch for cosmetics, shampoo, conditioner, body soap, and laundry detergent.

[0014] <<First Embodiment>> Figure 1 is a schematic front view showing a packaging bag (standing pouch) according to this embodiment. Figure 2 is a schematic exploded perspective view showing a pair of main body parts and bottom tape constituting the packaging bag shown in Figure 1. Figure 3 is a schematic cross-sectional view showing the structure of the packaging bag shown in Figure 1. Figure 4 is an enlarged plan view showing the vicinity S1 of the opening 21 of the packaging bag shown in Figure 1. Figure 5 is an enlarged plan view showing the vicinity S2 of the intended opening line shown in Figure 4. Figure 6 is an end view along the dashed line AA in Figure 5.

[0015] As shown in Figure 1, the packaging bag 10 (standing pouch) has a sealing portion 12 that seals the periphery of a pair of main body parts, a storage portion 11 that stores (can store) predetermined contents, an opening 21 for removing the contents when opened, and an opening guideline 26 to assist in opening. The sealing portion 12 has a first sealing portion 12a provided on one side of the storage portion 11 (the left side in the figure), a second sealing portion 12b provided on the other side of the storage portion 11 (the right side in the figure), a third sealing portion 12c provided on the bottom of the storage portion 11, and an opening sealing portion 12d.

[0016] In such a packaging bag 10, as shown in Figure 2, laminates 35A (front laminate) and 35B (back laminate), cut to a predetermined shape, are arranged facing each other. Laminate 35A becomes the front surface of the packaging bag 10, and laminate 35B becomes the back surface of the packaging bag 10. As shown in Figure 6, the laminate 35 has a laminated structure comprising a base layer L1, an adhesive layer L5a, an intermediate layer L2, a vapor-deposited layer L4, an adhesive layer L5b, and a sealant layer L3 in this order. Details of each layer will be described later.

[0017] The laminates 35A and 35B are heat-sealed at predetermined locations with the sealant layer L3 facing inward. In the packaging bag 10, the bottom tape 40 is heat-sealed between the laminates 35A and 35B at the bottom. The formation of the packaging bag by heat sealing can be carried out in the same way as conventional methods.

[0018] The bottom tape 40 has one mountain fold portion 41. That is, when the packaging bag 10 is standing upright, the bottom tape 40 is arranged in an inverted V shape (see Figures 2 and 3). The third seal portion 12c at the bottom of the packaging bag 10 is composed of a heat seal portion 14 and a heat seal portion 15, as shown in Figure 3. The heat seal portion 14 is the portion where the bottom 31a of the laminate 35A and one bottom 41a of the bottom tape 40 are heat-sealed. The heat seal portion 15 is the portion where the bottom 31b of the laminate 35B and the other bottom 41b of the bottom tape 40 are heat-sealed. As shown in Figure 1, the laminates 35A, 35B and the bottom tape 40 are heat-sealed so that the bottom of the area that contains the contents is curved and the upper side is arc-shaped.

[0019] As described above, the sealing portion 12 on the side of the packaging bag 10 has a first sealing portion 12a provided on the side of the dispensing opening 21 and a second sealing portion 12b provided on the opposite side in the horizontal direction (or MD) from the first sealing portion 12a. The widths of the first sealing portion 12a and the second sealing portion 12b of the sealing portion 12 are, for example, 5 to 18 mm, or 7 to 15 mm. A width of 5 mm or more for each sealing portion 12 tends to achieve sufficient sealing strength, while a width of 18 mm or less tends to make it easier to secure a sufficient amount of contents in the packaging bag 10.

[0020] As shown in Figure 1, the packaging bag 10 has fused portions 16 and 17 on both sides of the bottom (third seal portion 12c). In this embodiment, two fused portions 16 are formed vertically on one side of the packaging bag 10, and two fused portions 17 are formed vertically on the other side. The fused portions 16 and 17 join the laminate 35A and the laminate 35B. The fused portions 16 and 17 are areas where the sealant layers L3 of the laminates 35A and 35B are locally fused together through notches 44 and 45 provided in the bottom tape 40. As shown in Figure 3, the notches 44 and 45 of the bottom tape 40 are located in the region between the mountain fold portion 41 and the bottom edges 42 and 43, and are provided on the side of the bottom tape 40. The provision of fused sections 16 and 17 on both sides of the bottom further improves the self-supporting ability and drop resistance of the packaging bag 10. While this example illustrates the case where two pairs of notches 44 and 45 are provided on one side of the bottom tape 40 to form two fused sections 16 and 17, for example, a pair of notches may be provided on one side of the bottom tape 40 to form one fused section 16 or 17.

[0021] From the viewpoint of recyclability, it is preferable that the polyethylene resin content in the packaging bag 10 be 90% by mass or more. From the viewpoint of achieving a higher degree of monomaterialization, it is more preferable that the polyethylene resin content in the packaging bag 10 be 92% by mass or more, and even more preferable that be 95% by mass or more.

[0022] As shown in Figures 1 and 4, the outlet sealing portion 12d includes a tip sealing portion 22, a first outlet sealing portion 23, a second outlet sealing portion 24, and a connecting sealing portion 25.

[0023] The dispensing opening 21 is the part from which the contents are removed when the packaging bag is opened along the planned opening line 26, and includes the path 21b from the storage section 11. The dispensing opening 21 is defined by the first dispensing seal section 23 and the second dispensing seal section 24, which extend in a direction slightly oblique to the vertical direction, and the part including the path 21b is defined.

[0024] The tip seal portion 22 is a seal portion that forms the edge of the tip of the dispensing opening 21. The tip seal portion 22 and a part of the dispensing opening 21 serve as a gripping portion (gripping tab) for pulling the dispensing opening 21 when opening the packaging bag 10 in order to remove the contents contained in the storage portion 11. By pulling the gripping tab along the opening line 26 in the direction of arrow A, the opening 21a of the dispensing opening 21 opens, and the packaging bag 10 is opened. The gripping tab has a protrusion that extends outward from the packaging bag 10, and the gripping tab is designed to be pulled from the outside inward. The tip seal portion 22 is connected to the first dispensing seal portion 23 and the second dispensing seal portion 24.

[0025] The first removal seal portion 23 is a vertically extending seal portion provided on the outer edge side of the packaging bag 10, with its upper end connected to the tip seal portion 22 and its lower end connected to the first seal portion 12a via the connecting seal portion 25. The second removal seal portion 24 is a vertically extending seal portion provided inward from the first removal seal portion 23, with its upper end connected to the gripping tab and its lower end connected to the seal portion 13a of the receiving opening 13 via a curved surface portion. The first removal seal portion 23 and the second removal seal portion 24, like the first seal portion 12a and the second seal portion 12b, are portions where the sealant layers L3 of the laminates 35A and 35B, described later, are sealed together. The width of the first removal seal portion 23 and the second removal seal portion 24 in the machine direction may be, for example, 3 mm or more (or 4 mm or more).

[0026] As described above, the first removal seal portion 23 is connected to the first seal portion 12a via the connecting seal portion 25. In this case, the angle α formed by the outer edge of the first removal seal portion 23 and the outer edge of the connecting seal portion 25 is, for example, 90 degrees or more and 180 degrees or less, forming an obtuse angle.

[0027] The second removal seal portion 24 is formed to be short such that the distance D2 from the base 24a connected to the seal portion 13a to the tip 24b is, for example, 5 mm or more and 10 mm or less. For example, the length D2 of the second removal seal portion 24 may be shorter than half the length D1 of the first removal seal portion 23. Also, the second removal seal portion 24 is formed adjacent to the seal portion 13a of the receiving opening 13, and for example, the shortest separation distance (distance between their outer edges) at the point where the second removal seal portion 24 and the seal portion 13a face each other may be 5 mm or less.

[0028] The opening line 26 will be explained with reference to Figures 5 and 6. The opening line 26 is a line used to tear and cut the packaging bag 10 when opening the packaging bag 10 to transfer the contents contained in the storage section 11 to another container. As described later, the opening line 26 is formed by irradiating the packaging bag with laser light to form a linear void H. The void H is located between the vapor-deposited layer L4 and the adhesive layer L5b in the laminates 35A and 35B. The opening line 26 may be a solid line or a dashed line. The opening line 26 may be a straight line or a curved line. It is preferable that the opening line 26 be provided in a straight line along the MD of the laminates 35A and 35B because it provides superior tearability.

[0029] The opening line 26 extends from the first dispensing seal section 23, across the dispensing opening 21, to the second dispensing seal section 24. This makes the packaging bag even easier to open. The opening line 26 may extend from the end of the first dispensing seal section 23 opposite to the dispensing opening 21. The opening line 26 may extend from the end of the second dispensing seal section 24 opposite to the dispensing opening 21.

[0030] The packaging bag 10 has three opening lines 26 on both its front and back surfaces. In other words, the laminates 35A and 35B each have three linear voids that serve as opening lines. The number of opening lines on the front surface of the packaging bag 10 may be one or more, preferably two or more, and more preferably three or more. During the manufacturing process of the packaging bag, the notch may be misaligned from the intended position relative to the opening line. Even in such cases, having two or more opening lines on the front surface of the packaging bag 10 allows any of the opening lines to assist in opening. Therefore, the packaging bag 10 tends to have improved tear resistance. The number of opening lines on the back surface of the packaging bag 10 may be one or more, preferably two or more, and more preferably three or more, from the same viewpoint as the front surface.

[0031] Since the packaging bag 10 has opening lines 26 on both its front and back surfaces, the packaging bag 10 has excellent tear resistance whether the gripping tab is pulled towards the front surface of the packaging bag 10 or towards the back surface of the packaging bag 10.

[0032] The number of opening lines on the surface of the packaging bag 10 may be seven or less, preferably five or less, and more preferably three or less. This allows the packaging bag 10 to reduce the adhesion area between the sealant layers, as described later, and ensure ease of removing the contents. In addition, the laser irradiation time can be shortened, which tends to improve the manufacturing efficiency of the packaging bag 10. From a similar viewpoint, the number of opening lines on the back of the packaging bag 10 may be seven or less, preferably five or less, and more preferably three or less.

[0033] When the packaging bag 10 is viewed in plan view in the thickness direction, the opening lines 26 on the front and back surfaces of the packaging bag 10 are offset from each other. The offsetting of the opening lines 26 on the front and back surfaces means that, as shown in Figure 5, the opening lines 26 on the front and back surfaces are similar in shape, but are positioned so as not to overlap when the packaging bag 10 is viewed in plan view in the thickness direction. For example, if the opening line 26 is a straight line, the opening lines 26 on the front and back surfaces may be parallel when the packaging bag 10 is viewed in plan view in the thickness direction. For example, if the opening line 26 is a curve, the opening lines 26 on the front and back surfaces may be offset in the height direction of the packaging bag when the packaging bag 10 is viewed in plan view in the thickness direction.

[0034] When the packaging bag 10 is viewed in plan in the thickness direction, the shortest distance between the opening line on the front and the opening line on the back is preferably 0.2 mm or more, and more preferably 0.3 mm or more, from the viewpoint of preventing the packaging bag from becoming difficult to open due to fusion. When the packaging bag 10 is viewed in plan in the thickness direction, the shortest distance between the opening line on the front and the opening line on the back is preferably 1.5 mm or less, and more preferably 1.0 mm or less, from the viewpoint of ensuring sufficient tearability without the misalignment of the opening lines on the front and back spreading too wide.

[0035] If the packaging bag 10 has two or more opening lines 26 on its surface, the distance between adjacent opening lines may be, for example, 0.6 to 2.0 mm. If the packaging bag 10 has two or more opening lines 26 on its back surface, the distance between adjacent opening lines may be, for example, 0.6 to 2.0 mm.

[0036] The length of the void H in the thickness direction of the laminated bodies 35A and 35B may be 40 to 100 mm.

[0037] In the thickness direction of the packaging bag 10, at positions overlapping with the void H, there is a fused portion M where the sealant layers of the laminates 35A and 35B are fused together. The width W of the fused portion M is 5 to 100 μm. By having the width W within this numerical range, the packaging bag 10 is prevented from becoming difficult to open due to fusion, and the contents can be removed. The width W is 5 μm or more, and may be 10 μm or more, or 20 μm or more. The width W is 100 μm or less, and from the viewpoint of further preventing the packaging bag from becoming difficult to open due to fusion, it is preferably 80 μm or less, and more preferably 60 μm or less. The width W is the longest length of the fused portion M in the direction perpendicular to the thickness direction of the laminates 35A and 35B and the extension direction of the fused portion M. The width W may be a value measured by observing the cross-section of the laminates 35A and 35B with an optical microscope at an observation magnification of 500x.

[0038] The shape of the fused portion M may be substantially the same as the gap H. The fused portion M may be a solid line or a dashed line. The fused portion M may be a straight line or a curve.

[0039] In the thickness direction of the packaging bag 10, at positions overlapping with the void H, the base layer L1 has through-holes T that penetrate in the thickness direction. The through-holes T, together with the void H, serve as the starting point for tearing. Therefore, the packaging bag becomes even more tear-resistant.

[0040] The packaging bag 10 has a notch 27. The notch 27 is located at one end of the intended opening line 26 and is the starting point for opening the packaging bag 10, guiding the user when opening the packaging bag 10. The notch 27 may have the shape of a cut, notch, or indentation. In the example shown in the figure, the notch 27 is located just below the gripping tab on the outside of the packaging bag 10, but the notch 27 may be located elsewhere as long as it can guide the user to the intended opening line 26.

[0041] In the packaging bag 10, a notch 27 is provided at one end of the opening line 26. This allows for guidance during the opening process, thereby improving the opening performance.

[0042] In the packaging bag 10, the straight length from the base 24a to the tip 24b of the second dispensing seal portion 24 may be 5 mm or more and 10 mm or less. When the above distance D2 is 5 mm or more, it is possible to perform the refilling work stably when opening the packaging bag 10 and performing the refilling work. Also, when the above distance D2 is 10 mm or less, when the packaging bag 10 is opened and the dispensing opening 21 of the packaging bag 10 is inserted into the container to be refilled, the path 21b does not become narrowed, and the refilling work can be performed quickly.

[0043] In the packaging bag 10, the angle α between the outer edge along the dispensing opening 21 and the outer edge of the connecting seal portion 25 that connects the dispensing opening 21 to the first seal portion 12a is obtuse. According to this configuration, when the packaging bag 10 is opened and the dispensing opening 21 is inserted into the container to be refilled, the dispensing opening 21 is easier to fit into the container (bottle, etc.), making the refilling process easier.

[0044] In the packaging bag 10, the stiffness strength of the laminate 35 in the MD (Metal Modular Strength) may be 200 mN / 15 mm or less. In this case, since the laminate 35 will be made of a softer material, it will be easier to squeeze out (dispense) the contents from the packaging bag 10 formed using such a laminate 35.

[0045] In the packaging bag 10, the width of the first dispensing seal portion 23 and the second dispensing seal portion 24 in the machine direction is 3 mm or more. In this case, the rigidity of the dispensing opening 21 is increased, and when the dispensing opening 21 of the packaging bag 10 is inserted into the container to be refilled, dispensing can be performed stably. This makes the refilling work easier.

[0046] In the packaging bag 10, the first dispensing seal portion 23 is provided on the outer edge side of the packaging bag 10, and the second dispensing seal portion 24 is provided inward from the first dispensing seal portion 23, with the length D2 of the second dispensing seal portion 24 being shorter than half the length D1 of the first dispensing seal portion 23. Furthermore, the shortest separation distance D3 between the second dispensing seal portion 24 and the seal portion 13a of the storage opening 13 is 5 mm or less. In this case, even when using a relatively soft material such as polyethylene resin, rigidity can be ensured at the dispensing opening 21, making the refilling process more reliable.

[0047] The packaging bag 10 has a gripping tab that can be grasped by the user of the packaging bag 10. The gripping tab protrudes outward from the packaging bag 10. This makes it easier to open the packaging bag 10.

[0048] The capacity of the packaging bag 10 may be, for example, 80 to 800 ml. Examples of contents that can be contained in the packaging bag 10 include liquid surfactants such as shampoo, conditioner, body soap, liquid detergent, and liquid fabric softener; liquid cosmetics such as lotion, toner, and hair oil; and liquid, powder, and particulate seasonings.

[0049] <<Second Embodiment>> A resealable packaging bag will be described as a packaging bag according to the second embodiment of this disclosure. Unless otherwise described below, it is the same as the packaging bag according to the first embodiment. The resealable packaging bag is used, for example, to contain face masks.

[0050] Figure 7 is a schematic front view showing a packaging bag according to this embodiment. The packaging bag 100 shown in Figure 7 consists of opposing surface laminates (laminated 35A) and back laminates (laminated 35B). The packaging bag 100 has a storage section 11 for storing (or being able to store) predetermined contents, a sealing section 12 that seals the periphery of the laminates 35A and 35B, an opening line 26 to assist in opening, and a zipper mechanism 110. The packaging bag 100 can also be obtained, for example, by folding one laminate 35 and heat-sealing the overlapping periphery sections. In this case, the packaging bag 100 becomes a three-sided bag composed of opposing laminates 35A and 35B and a connecting section that connects them.

[0051] The chuck mechanism 110 consists of a female fitting member and a male fitting member. The chuck mechanism 110 may be attached to any position in the packaging bag 100 between the laminated body 35A and the laminated body 35B. However, from the viewpoint of ensuring that the contents can be adequately contained, it is preferable that the chuck mechanism 110 be positioned near the heat-sealed portion between the laminated body 35A and the laminated body 35B.

[0052] The male fitting member, which constitutes the chuck mechanism 110, has, for example, a tape-shaped support portion fixed to the sealant layer of the laminate 35A and a protrusion provided on the support portion. The female fitting member, which constitutes the chuck mechanism 110, has, for example, a tape-shaped support portion fixed to the laminate 35B and two projections provided on the support portion. The two projections form a space for accommodating and fitting the protrusion of the male fitting member.

[0053] The packaging bag 100 has three opening lines 26 on both its front and back surfaces. That is, the laminates 35A and 35B each have three linear voids that serve as opening lines. The opening lines 26 extend from the seal portion 12 on one side of the packaging bag, across the storage portion, to the seal portion 12 on the other side of the packaging bag. This makes the packaging bag even easier to open. When the packaging bag 100 is viewed in plan in the thickness direction, the opening lines 26 on the front and back surfaces of the packaging bag 100 are offset from each other. The packaging bag 100 has fused portions where the sealant layers of the laminates 35A and 35B are fused together at positions overlapping with the linear voids. The width of these fused portions is 5 to 100 μm. The number of opening lines on the front and back surfaces of the packaging bag 100 may be the same as that of the packaging bag according to the first embodiment. When the packaging bag 100 is viewed in plan in the thickness direction, the shortest distance between the opening line on the front surface and the opening line on the back surface may be the same as that of the packaging bag according to the first embodiment. If the packaging bag 100 has two or more opening lines 26 on its surface, the distance between adjacent opening lines may be the same as that of the packaging bag according to the first embodiment.

[0054] Examples of items that can be contained include face masks, face masks, supplements, seasonings, dried foods, processed meat products, dairy products (cheese), frozen foods, candy, gum, and snack foods.

[0055] <<Laminate>> Each layer of the laminate constituting the packaging bag of this disclosure will be described.

[0056] [Base material layer L1] The base layer L1 consists of a stretched polyethylene film. Here, an unstretched polyethylene film is a polyethylene film in which no stretching treatment is performed during film formation, and which has a structure in which spherical crystals (spherulites) of about 10 to 100 μm, composed of randomly folded polyethylene molecular chains, are linked together by amorphous molecules. A stretched polyethylene film, on the other hand, is a polyethylene film in which a stretching treatment is performed during film formation, and which has an arranged structure.

[0057] The polyethylene resin content in the base layer L1 may be 50% by mass or more, 80% by mass or more, or 100% by mass, based on the total amount of the base layer L1. Using polyethylene resin as the material for the base layer L1 is preferable from the viewpoint of recyclability. Furthermore, the higher the polyethylene resin content in the base layer L1, the better the recyclability.

[0058] The polyethylene resin contained in the base layer L1 may be acid-modified polyethylene obtained by graft-modifying polyethylene with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, etc.

[0059] The density of the polyethylene resin contained in the base layer L1 is 0.910 g / cm³. 3 Preferably, it should be 0.930 g / cm³ or more. 3 It is more preferable that the amount be greater than or equal to 0.950 g / cm³. 3 It is even more preferable that the density of the polyethylene resin is 0.910 g / cm³. 3 As a result, when the laminate is heat-sealed to form a bag, only the sealant layer L3 is easily fused, thus improving bag-making suitability. Furthermore, the density of the polyethylene resin is 0.910 g / cm³. 3 When the above conditions are met, good printability is achieved when forming a printed layer on the substrate layer L1. Furthermore, the density of the polyethylene resin is 0.910 g / cm³. 3 This makes it easier to suppress the stretching and wrinkling of the base material layer L1 during roll processing.

[0060] The base layer L1 may be a multilayer structure comprising multiple unstretched films, each containing polyethylene of different densities as its main component. The base layer L1 may be multilayered as appropriate, taking into consideration the processability, rigidity, stiffness, heat resistance, and powder shedding during transport of the films constituting the base layer L1. Furthermore, the content of slip agents, antistatic agents, etc., may be varied in each layer during lamination. The base layer L1 comprising multiple layers can be laminated into a film by extrusion molding, co-extrusion molding, sheet molding, co-extrusion blow molding, etc. The total thickness of the base layer L1 comprising multiple layers is preferably about 10 to 100 μm, and more preferably 15 to 50 μm.

[0061] The stretched film constituting the base layer L1 may have a molecular orientation degree (MOR) of 1.07 or less, 1.05 or less, or 1.04 or less. The lower the molecular orientation degree, the better the isotropy of the film. When the molecular orientation degree is 1.07 or less, the adhesion (peel resistance) of the base layer L1 in the laminate tends to be good. The molecular orientation degree can be measured using a molecular orientation meter.

[0062] The thermal shrinkage rate of the base material layer L1 after heating at 100°C for 15 minutes in the machine direction (hereinafter simply referred to as MD) and the perpendicular direction (hereinafter simply referred to as TD) is preferably 3% or less, more preferably 2% or less, and even more preferably 1.5% or less. When the thermal shrinkage rate of the base material layer L1 is within the above range, it is easier to suppress the stretching and wrinkling of the base material layer L1 during roll processing, and it is also easier to suppress the occurrence of cracks in the vapor-deposited layer L4 when a vapor-deposited layer L4 is provided on the base material layer L1.

[0063] Here, the thermal shrinkage rate (%) is a value calculated by the following formula. Thermal shrinkage rate (%) = {(Length before heating - Length after heating) / Length before heating} × 100 The procedure for measuring the thermal shrinkage rate is as follows: (1) Cut out a 20cm x 20cm piece of the base layer L1 to use as a measurement sample. (2) Draw a 10cm line on the MD or TD of the measurement sample (length before heating). (3) Heat the sample to be measured at 100°C for 15 minutes. (4) Measure the length of the MD or TD of the written line (length after heating). (5) Calculate the thermal shrinkage rate using the above formula.

[0064] The thickness of the base layer L1 is not particularly limited. Depending on the application, the thickness can be 6 to 200 μm. From the viewpoint of ensuring strength, the thickness of the base layer L1 is preferably 10 μm or more, and more preferably 20 μm or more. The thickness of the base layer L1 is preferably 50 μm or less, and more preferably 30 μm or less, as forming through holes penetrating the base layer L1 further improves tear resistance.

[0065] From the viewpoint of improving adhesion with adjacent layers, the substrate layer L1 may be subjected to various pretreatments such as corona treatment, plasma treatment, low-temperature plasma treatment, flame treatment, chemical treatment, solvent treatment, and ozone treatment on its laminated surface, to the extent that it does not impair barrier performance, or a coating layer such as an easy-adhesion layer may be provided.

[0066] The substrate layer L1 may contain additives such as fillers, antiblocking agents, antistatic agents, plasticizers, lubricants, and antioxidants. These additives may be used individually or in combination of two or more.

[0067] [Adhesive layer L5a, L5b] The adhesive used to form the adhesive layers L5a and L5b can be selected according to the bonding method, but urethane-based adhesives, polyester-based adhesives, etc., can be used. By providing adhesive layers L5a and L5b, the adhesion between the base layer L1 and the intermediate layer L2, and between the intermediate layer L2 and the sealant layer L3 is improved, making delamination less likely and maintaining the pressure resistance and impact resistance of the packaging bag.

[0068] Adhesive layers L5a and L5b are preferably chlorine-free. The absence of chlorine in adhesive layers L5a and L5b prevents discoloration of the adhesive and recycled resin after recycling, and prevents odor generation during heat treatment. From an environmental perspective, using biomass materials for adhesive layers L5a and L5b is preferable. Biomass polyethylene can also be used instead of polyethylene. From an environmental perspective, solvent-free adhesives are preferable.

[0069] The thickness of the adhesive layers L5a and L5b may be, for example, 0.1 to 10 μm, 0.1 to 5.0 μm, or 0.2 to 2.0 μm.

[0070] The adhesive layers L5a and L5b may be composed of adhesive resin. Such adhesive layers L5a and L5b can be formed by extrusion lamination of adhesive resin. Furthermore, the sealant can also be formed together with the adhesive layer of adhesive resin by co-extrusion lamination.

[0071] As the adhesive resin, for example, polyethylene resin may be used. If adhesion is important, the adhesive resin may include, for example, acid-modified polyethylene. The sealant formed by co-extrusion lamination can use the same materials as the sealant described later.

[0072] [Middle layer L2] The laminate 35 has an intermediate layer, and since the intermediate layer is an unstretched polyethylene film, voids H are formed while suppressing damage to the sealant layer. Furthermore, since the sealant layer is not exposed in the packaging bag containing such a laminate 35, the occurrence of delamination is suppressed. In addition, packaging bags containing such a laminate 35 tend to suppress the occurrence of bag rupture caused by internal pressure when dropped or crushed.

[0073] The intermediate layer L2 is made of an unoriented polyethylene film. The thickness of the intermediate layer L2 is, for example, 5 to 800 μm, and may be 5 to 500 μm or 10 to 50 μm.

[0074] The polyethylene resin content in the intermediate layer L2 may be 50% by mass or more, 80% by mass or more, or 100% by mass, based on the total amount of the intermediate layer L2. Using polyethylene resin as the material for the intermediate layer L2 is preferable from the viewpoint of recyclability. Furthermore, the higher the polyethylene resin content in the intermediate layer L2, the better the recyclability.

[0075] The polyethylene resin contained in the intermediate layer L2 may be acid-modified polyethylene obtained by graft-modifying polyethylene with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, etc.

[0076] The melting point of the intermediate layer L2 is preferably 120°C or higher, and more preferably 125°C or higher. Examples of polyethylene constituting the intermediate layer L2 include high-density polyethylene (HDPE) and medium-density polyethylene (MDPE). Of these, HDPE and MDPE with a density of 0.925 g / cm³ are preferred from the viewpoint of heat resistance. 3 It is preferable to use the above materials. In particular, materials with a density of 0.93 to 0.98 g / cm³ are preferred. 3 It is preferable to use high-density polyethylene within the specified range.

[0077] The intermediate layer L2 may contain components other than polyethylene resin. Examples of such components include those similar to those in the base layer L1.

[0078] [Sealant layer L3] The sealant layer L3 contains a polyethylene resin. The polyethylene resin content in the sealant layer L3 may be 50% by mass or more, 80% by mass or more, or 100% by mass, based on the total amount of the sealant layer L3. Using a polyethylene resin as the material for the sealant layer L3 is preferable from the viewpoint of recyclability. Furthermore, the higher the polyethylene resin content in the sealant layer L3, the better the recyclability.

[0079] The thickness of the sealant layer L3 is, for example, 40 to 150 μm, and may be 20 to 250 μm. The melting point of the sealant layer L3 is preferably 120°C or lower, and more preferably 95 to 110°C. The sealant layer L3 has a density of 0.925 g / cm 3 less than (more preferably 0.900 to 0.920 g / cm 3 ), and is preferably composed of a polyethylene resin. Specific examples include linear low density polyethylene (LLDPE) and very low density polyethylene (VLDPE). These polyethylenes may be blended and used.

[0080] The polyethylene resin constituting the sealant layer L3 is preferably C4-LLDPE because of its even better tearability. C4-LLDPE is a type of LLDPE (linear low density polyethylene) composed of a copolymer of ethylene and 1-butene, and has a molecular structure in which the main chain of LLDPE derived from ethylene has a side chain with 4 carbon atoms derived from 1-butene. C4-LLDPE has relatively low tensile impact strength, tensile strength, and tensile modulus because its side chains are shorter and its melt flow rate (MFR) is lower than those of C6-LLDPE and C8-LLDPE. Therefore, when the polyethylene resin constituting the sealant layer L3 is C4-LLDPE, the laminate 35 has even better MD tearability.

[0081] As part or all of the polyethylene resin contained in the sealant layer L3, biomass polyethylene using biomass-derived ethylene as a raw material may be used. Such a sealant film is disclosed, for example, in JP-A-2013-177531. The sealant layer L3 may contain mechanically recycled polyethylene using used polyethylene products or resin (so-called burrs) generated during the manufacturing process of polyethylene products as raw materials.

[0082] [Vapor deposition layer L4] Examples of constituent materials for the vapor-deposited layer L4 include inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. From the viewpoint of transparency and barrier properties, the inorganic oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, from the viewpoint of excellent tensile stretchability during processing, it is preferable that the vapor-deposited layer L4 is a layer containing silicon oxide. By using the vapor-deposited layer L4, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the laminate.

[0083] The O / Si ratio of the vapor-deposited layer L4 is preferably 1.7 or higher. When the O / Si ratio is 1.7 or higher, the content of metallic Si is suppressed, making it easier to obtain good transparency. Furthermore, the O / Si ratio is preferably 2.0 or lower. When the O / Si ratio is 2.0 or lower, the crystallinity of SiO is increased, which prevents the vapor-deposited layer L4 from becoming too hard, and good tensile strength can be obtained. This makes it possible to suppress the occurrence of cracks in the vapor-deposited layer L4 when laminating the adhesive layer L5b. In addition, even after forming into a packaging bag, the base layer L1 may shrink due to the heat during the boiling process, but when the O / Si ratio is 2.0 or lower, the vapor-deposited layer L4 can easily follow the above shrinkage, and the decrease in barrier properties can be suppressed. From the viewpoint of obtaining these effects more fully, the O / Si ratio of the vapor-deposited layer L4 is preferably 1.75 or higher and 1.9 or lower, and more preferably 1.8 or higher and 1.85 or lower.

[0084] The O / Si ratio of the deposited layer L4 can be determined by X-ray photoelectron spectroscopy (XPS). For example, the measurement can be performed using an X-ray photoelectron spectrometer (manufactured by JEOL Ltd., product name: JPS-90MXV) with a non-monochromatic MgKα (1253.6 eV) X-ray source and an X-ray output of 100 W (10 kV-10 mA). For quantitative analysis to determine the O / Si ratio, relative sensitivity factors of 2.28 for O1s and 0.9 for Si2p can be used.

[0085] The thickness of the vapor-deposited layer L4 is preferably between 10 nm and 50 nm. A thickness of 10 nm or more provides sufficient gas barrier properties. A thickness of 50 nm or less suppresses crack formation due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. Furthermore, a thickness of 50 nm or less is preferable from an economic standpoint because it makes it easier to suppress cost increases due to increased material usage and longer film formation times. From the same viewpoint as above, a thickness of 20 nm or more and 40 nm is more preferable.

[0086] The vapor-deposited layer L4 can be formed, for example, by vacuum deposition. Vacuum deposition can be performed using either physical vapor deposition or chemical vapor deposition. Examples of physical vapor deposition methods include vacuum deposition, sputtering, and ion plating, but are not limited to these. Examples of chemical vapor deposition methods include thermal CVD, plasma CVD, and photoCVD, but are not limited to these.

[0087] In the vacuum deposition methods described above, resistance heating vacuum deposition, EB (Electron Beam) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, and plasma chemical vapor deposition (PECVD) are particularly preferred. However, considering productivity, vacuum deposition is currently the most superior method. For the heating means in vacuum deposition, it is preferable to use one of the following methods: electron beam heating, resistance heating, or induction heating.

[0088] The laminate 35 has a void H between the vapor-deposited layer L4 and the adhesive layer L5b. The maximum length of the void H may be, for example, 20 to 40 mm. The void H is preferably provided in a straight line along the MD of the laminate 35 because it provides even better tear resistance. If the sealant layer L3 contains C4-LLDPE, the void H is preferably provided in a straight line along the MD of the laminate 35 because it provides even better tear resistance to the laminate 35.

[0089] From the viewpoint of recyclability, the total content of polyethylene resin in the laminate 35 is preferably 90% by mass or more, based on the total mass of the laminate 35. From the viewpoint of achieving a higher degree of monomaterialization, the polyethylene resin content in the laminate 35 is more preferably 92% by mass or more, and even more preferably 95% by mass or more.

[0090] Although the packaging bags according to the first and second embodiments have been described in detail above, the packaging bags of this disclosure are not limited to the above embodiments and examples. For example, the packaging bags of this disclosure may be packaging bags other than standing pouches and resealable packaging bags. The packaging bags of this disclosure may be, for example, two-sided bags, four-sided bags, gusseted bags or foldable bags. The packaging bags of this disclosure do not have a zipper mechanism. The packaging bags of this disclosure can be subjected to heat sterilization treatment such as boiling.

[0091] Furthermore, in the packaging bag 10, when the packaging bag 10 is viewed in plan in the thickness direction, the opening lines 26 on the front and back surfaces of the packaging bag 10 are offset from each other. However, the opening lines on the front and back surfaces of the packaging bag of this disclosure do not have to be offset from each other. In other words, the opening lines on the front and back surfaces of the packaging bag of this disclosure may be positioned to overlap when the packaging bag is viewed in plan in the thickness direction.

[0092] Furthermore, the base layer of the laminate used in the packaging bag may be made of unoriented polyethylene film. Using unoriented polyethylene film for the base layer makes it less likely for defects to penetrate the base layer during the formation of voids H. This suppresses delamination caused by defects. Additionally, packaging bags containing such laminates tend to be less prone to rupture caused by internal pressure from drops or crushing. In this case, the base layer does not need to have through holes.

[0093] Furthermore, the intermediate layer of the laminate used in the packaging bag may be made of stretched polyethylene film. The polyethylene film may be uniaxially stretched or biaxially stretched. Also, the laminate used in the packaging bag does not need to have an intermediate layer.

[0094] Furthermore, the laminate used in the packaging bag may further comprise other layers in addition to the base layer, intermediate layer, sealant layer, adhesive layer, and vapor-deposited layer.

[0095] [Other layers] The laminate may have an anchor coat layer between the base layer L1 and the sealant layer L3. The anchor coat layer may be a very thin layer that does not affect the recyclability of the laminate, and can be formed using an anchor coat agent. Examples of anchor coat agents include acrylic resin, epoxy resin, acrylic urethane resin, polyester polyurethane resin, polyether polyurethane resin, and polyvinyl alcohol resin. From the viewpoint of heat resistance and interlayer adhesion strength, acrylic urethane resin and polyester polyurethane resin are preferred as anchor coat agents.

[0096] The laminate may further include, for example, a printed layer. The printed layer may be provided on the surface of the base layer L1 opposite to the adhesive layer L5a, between the base layer L1 and the adhesive layer L5a, or between the adhesive layer L5a and the intermediate layer L2. The inclusion of a printed layer in the laminate increases the size of the through-holes formed in the base layer. As a result, the tear resistance of the laminate tends to be even better.

[0097] When a printed layer is provided, it is preferable to use a printing ink that does not contain chlorine, from the standpoint of preventing discoloration or odor generation when the printed layer is remelted. Furthermore, from the standpoint of environmental consideration, it is preferable to use biomass materials in the compounds contained in the printing ink.

[0098] For example, the laminate does not need to have adhesive layers L5a and L5b.

[0099] The following describes in detail a method for manufacturing a packaging bag according to one embodiment of this disclosure.

[0100] <Manufacturing method for packaging bags> A method for manufacturing a standing pouch will be described as a method for manufacturing a packaging bag according to one embodiment of this disclosure.

[0101] The method for manufacturing a packaging bag according to this embodiment comprises the following steps (a) and (b). Step (a): Step of preparing the first packaging bag Step (b): Step of forming an opening line on the first packaging bag to assist in opening and obtaining a second packaging bag.

[0102] <<Process (a)>> Figure 8(a) is a schematic front view showing an example of the first packaging bag. Figure 9(a) is an end view along the dashed line BB in Figure 8(a). The laminate 2 constituting the first packaging bag 1 has a laminated structure comprising a base layer L1, an adhesive layer L5a, an intermediate layer L2, a vapor-deposited layer L4, an adhesive layer L5b, and a sealant layer L3 in this order. The laminate 2 may be the same as the laminate 35 described above, except that it does not have voids or through holes. The first packaging bag 1 may be the same as the packaging bag 10 described above, except that the surface laminate is laminate 2A, the back laminate is laminate 2B, and it does not have an opening line.

[0103] <<Process (b)>> Figure 8(b) is a schematic front view showing an example of the second packaging bag. Figure 9(b) is a schematic end view showing the irradiation of the first packaging bag with laser light along the dashed line BB in Figure 8(a). Figure 9(c) is an end view along the dashed line CC in Figure 8(b). In step (b), as shown in Figure 9(b), laser light a2 is irradiated onto the first packaging bag 1 from the light source a1 to volatilize a portion of the laminates 2A and 2B, thereby forming a linear void H that will become the opening line. The laser light is absorbed by the adhesive layer L5a, the vapor-deposited layer L4, and the adhesive layer L5b, generating heat. As a result, a portion of these layers and adjacent layers volatilizes. As shown in Figures 8(b) and 9(b), a linear void H (opening line 26) is formed. Furthermore, the packaging bag after this process has a fused portion where the sealant layers of the surface laminate and the back laminate are fused together at a position overlapping with a linear void, and the width of the fused portion is 5 to 100 μm. The laser beam a2 is irradiated onto the packaging bag 10 from both the surface (laminated 2A) side and the back (laminated 2B) side of the packaging bag 1. At this time, when the packaging bag 10 is viewed in the thickness direction from above, the laser beam is irradiated so that the opening lines 26 on the surface and back of the packaging bag 10 are offset from each other (do not overlap). In other words, when the first packaging bag is viewed in the thickness direction from above, the laser beam is irradiated onto a different area on the back of the first packaging bag than the area on the surface of the first packaging bag that is irradiated with laser beam. For example, if the opening line 26 is a straight line, when the first packaging bag is viewed in the thickness direction from above, the straight areas irradiated with laser beam on the surface and back may be parallel to each other and do not overlap. For example, if the opening line 26 is curved, when the first packaging bag is viewed in plan in the thickness direction, the curved regions on the front and back surfaces that are irradiated with laser light may be offset in the height direction of the packaging bag without overlapping.

[0104] Since polyethylene resin does not absorb laser light, the energy penetrates the laminate located in front of the laser light source and reaches the sealant layer of the laminate located behind it. When the packaging bag 1 is viewed in plan in the thickness direction, if the area on the front side of the packaging bag 1 irradiated with laser light and the area on the back side irradiated with laser light are in the same position, the sealant layers are strongly fused together. As a result, even when the packaging bag is pressed, the fused part is difficult to peel off, and it is difficult to remove the contents. On the other hand, when the packaging bag 1 is viewed in plan in the thickness direction, if the areas on the front side of the packaging bag 1 irradiated with laser light and the areas on the back side irradiated with laser light are misaligned, a weakly fused part M is formed where the sealant layers are fused together. The fused part M can be easily peeled off by pressing the packaging bag. In addition, the void H formed by the laser light becomes an opening line that assists in opening the bag. As a result, a packaging bag is obtained that has sufficient tearability while allowing the contents to be removed.

[0105] The base layer L1 of the laminates 2A and 2B is made of polyethylene film. Polyethylene film absorbs laser light less readily than films made of other resins. Therefore, compared to packaging bags that use films made of other resins as the base layer, packaging bags 1 are more likely to form linear voids. In the packaging bag manufacturing method according to this embodiment, linear voids are easily formed, making it possible to increase the laser light scanning speed. Therefore, the packaging bag manufacturing method according to this embodiment is highly efficient in terms of production. Furthermore, because the laser light scanning speed can be increased, it is possible to make the shape of the linear voids long curves or to increase the distance between linear voids. In other words, the packaging bag manufacturing method according to this embodiment can be said to be a highly versatile manufacturing method.

[0106] Furthermore, because the base layer L1 is a stretched polyethylene film, through holes are formed in the base layer L1 as voids are created. If the laminate does not have an intermediate layer, damage occurs to the sealant layer during the through-hole formation process. On the other hand, the laminate 30 has an intermediate layer, and since the intermediate layer is an unstretched polyethylene film, damage to the sealant layer is less likely to occur.

[0107] Specifically, the laser light to be irradiated can be a laser emitted from a carbon dioxide laser or a YAG laser, and from the viewpoint of productivity, the laser light emitted from a carbon dioxide laser is preferred.

[0108] The wavelength of the laser light to be irradiated may be, for example, 9.2 to 10.8 μm.

[0109] The scanning speed of the irradiated laser beam may be 100 to 1000 mm / second.

[0110] The output power of the laser beam used for irradiation may be between 20 and 80 watts.

[0111] Although a method for manufacturing a packaging bag according to one embodiment has been described in detail above, the method for manufacturing a packaging bag according to this disclosure is not limited to the above embodiment. For example, the first packaging bag may be a packaging bag other than a standing pouch. Examples of such packaging bags include two-sided bags, three-sided bags, four-sided bags, gusseted bags, or fold-over bags. The first packaging bag may or may not have a zipper mechanism. Furthermore, the laminate used in the packaging bag is not limited to the above examples. [Examples]

[0112] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited to the following examples.

[0113] <Fabrication of laminates> <<Example 1>> The following materials were prepared as the base layer, first adhesive layer, intermediate layer, second adhesive layer, and sealant layer. The materials for the base layer, intermediate layer, and sealant layer of each example and comparative example are shown in Table 1. • Substrate layer: Biaxially oriented HDPE film (thickness: 25 μm, density: 0.948 g / cm³) 3 (Melting point: 127.8℃) • First adhesive layer: Urethane-based adhesive • Intermediate layer: Unoriented HDPE film (thickness: 32 μm, density: 0.948 g / cm³) 3 (Melting point: 135℃) • Second adhesive layer: Urethane-based adhesive • Sealant layer: C4-LLDPE (thickness: 100 μm, density: 0.916 g / cm³) 3 MFR: 4g / 10min, melting point: 104℃)

[0114] A silica vapor-deposited film (vapor-deposited layer) was formed on one of the main surfaces of the intermediate layer by vacuum deposition.

[0115] The substrate layer and the surface of the intermediate layer that does not have a vapor-deposited layer were bonded together via a first adhesive layer (thickness: 1-2 μm). Then, the vapor-deposited layer and the sealant layer were bonded together via a second adhesive layer (thickness: 1-2 μm) to obtain a laminate.

[0116] Three laminates were prepared and used as the main body (laminated 35A, 35B) and bottom material (bottom tape 40), respectively, to create the first packaging bag 1 (standing pouch) with the configuration shown in Figure 8(a). The pouch size was as follows. ·Top and bottom: 230mm ·Width: 140mm • Fold width: 40mm

[0117] An opening guide line 26 was formed on the first packaging bag, extending from the first dispensing seal section 23 across the dispensing opening 21 to the second dispensing seal section 24. The opening guide line 26 was formed to follow the MD. The opening guide line 26 was a solid line and a straight line. The opening guide line 26 was formed by irradiating the front and back sides of the packaging bag with laser light. At this time, when the packaging bag 1 was viewed in plan in the thickness direction, the laser light was irradiated so that the opening guide lines 26 on the front and back sides of the packaging bag 10 were offset from each other. The laser light irradiation conditions were as follows. Three opening guide lines 26 were formed on both the front and back sides of the packaging bag 10. When the packaging bag 10 was viewed in plan, the distance between adjacent opening guide lines on the front side of the packaging bag 10 was 1 mm. When the packaging bag 10 was viewed in plan, the shortest distance between the opening guide line on the front side and the opening guide line on the back side was 0.5 mm. This resulted in the second packaging bag. Table 1 shows whether or not there was a misalignment between the opening lines on the front and back of the second packaging bag for each example and comparative example.

[0118] • Laser: ML-Z9600 (manufactured by Keyence Corporation) • Laser beam power: 80% (24W) • Scanning speed: 1100 mm / second • Laser light wavelength: 10.6 μm

[0119] <<Example 2>> A laminate and a second packaging bag were obtained in the same manner as in Example 1, except that the following material was used as the intermediate layer. • Interlayer: Biaxially oriented HDPE film (thickness: 25 μm, density: 0.948 g / cm³) 3 (Melting point: 127.8℃)

[0120] <<Example 3>> A laminate and a second packaging bag were obtained in the same manner as in Example 1, except that the following materials were used as the base layer. • Substrate layer: Unoriented HDPE film (thickness: 35 μm, density: 0.948 g / cm³) 3 (Melting point: 135℃)

[0121] <<Example 4>> A laminate and a second packaging bag were obtained in the same manner as in Example 1, except that the following materials were used as the base layer and intermediate layer. • Substrate layer: Unoriented HDPE film (thickness: 35 μm, density: 0.948 g / cm³) 3 (Melting point: 135℃) • Interlayer: Biaxially oriented HDPE film (thickness: 25 μm, density: 0.948 g / cm³) 3 (Melting point: 127.8℃)

[0122] <<Comparative Example 1>> A laminate and a first packaging bag were obtained in the same manner as in Example 1, except that the following materials were used as the base layer and intermediate layer. A second packaging bag was obtained by irradiating the first packaging bag with a laser in the same manner as in Example 1, except that the shortest distance between the opening line on the front and the opening line on the back was set to 0 mm (when the packaging bag 10 is viewed from above, the opening lines on the front and back sides of the second packaging bag are not misaligned with each other). • Substrate layer: ONY film (thickness: 15 μm) • Intermediate layer: VM-PET film (product name, PET film with aluminum vapor deposition, manufactured by Toray Film Processing Co., Ltd., film thickness 12 μm)

[0123] <<Comparative Example 2>> A laminate and a second packaging bag were obtained in the same manner as in Example 1, except that the following materials were used as the base layer and intermediate layer. • Substrate layer: ONY film (thickness: 15 μm) • Intermediate layer: VM-PET film (product name, PET film with aluminum vapor deposition, manufactured by Toray Film Processing Co., Ltd., film thickness 12 μm)

[0124] <<Comparative Example 3>> A laminate and a first packaging bag were obtained in the same manner as in Example 1. The second packaging bag was obtained by irradiating the first packaging bag with a laser in the same manner as in Example 1, except that the shortest distance between the opening line on the front and the opening line on the back was set to 0 mm (when the packaging bag 10 is viewed from above, the opening lines on the front and back sides of the second packaging bag are not misaligned with each other).

[0125] <Evaluation of tear resistance> For each example and comparative example, the second packaging bag was gripped by hand and pulled along the intended opening line. The tear resistance was evaluated according to the following criteria. The results are shown in Table 2. (standard) A: It will be opened along the designated opening line. B: It opens along the designated opening line when pressure is applied. C: Cannot be opened

[0126] <Evaluation of the fused joint on the front and back sides> For each example and comparative example, the surface laminate and the back laminate were separated at the portion of the second packaging bag where the intended opening line was formed. The peelability was evaluated according to the following criteria. The results are shown in Table 2. (standard) A: The surface laminate and the back laminate can be separated. B: There is some resistance (it requires force), but the surface laminate and the back laminate can be separated. C: Cannot be peeled off

[0127] <Cross-sectional observation> The cross-sections of the surface laminate and back laminate in the portion where the opening line was formed on the second packaging bag of each example and comparative example were observed using an optical microscope (observation magnification: 500x). In the second packaging bags of Examples 1 and 2, it was confirmed that through holes were formed in the base material layer. Furthermore, the damage to the sealant layer was evaluated according to the following criteria. In addition, the width W of the fused portion M (the fused portion at the position overlapping the opening line) was measured. The results are shown in Table 2. (standard) A: It has scratches. B: No scratches

[0128] <Evaluation of drop strength> 400 ml of cold water was filled into the second packaging bag of each example and comparative example, and it was dropped from a height of 1 m. After the drop, the area where the intended opening line of the second packaging bag was formed was checked for damage and evaluated according to the following criteria. The results are shown in Table 2. (standard) A: It has scratches. B: No scratches

[0129] <Evaluation of recyclability> For each example and comparative example, the mass percentage of the same resin was calculated based on the total amount of the second packaging bag. Specifically, for Examples 1-4 and Comparative Example 3, the mass percentage of polyethylene resin was calculated, while for Comparative Examples 1 and 2, the mass percentage of nylon resin was calculated. The mass percentage of the resin was evaluated according to the following criteria. The results are shown in Table 2. (standard) A: The mass percentage of the same resin system is 90% or more by mass. B: The mass percentage of the same resin system is less than 90% by mass.

[0130] [Table 1]

[0131] [Table 2] [Explanation of Symbols]

[0132] 1, 10, 100…Packaging bag, 11…Storage section, 12, 13a…Seal section, 26…Opening line, 35A…Laminate (surface laminate), 35B…Laminate (backside laminate), 40…Bottom tape, 110…Chuck mechanism, a2…Laser beam, H…Void (Opening line 26), L1…Base layer, L2…Intermediate layer, L3…Sealant layer, L4…Vapor deposition layer, L5a, L5b…Adhesive layer.

Claims

1. The process includes forming an opening line on the packaging bag to assist in opening it. The aforementioned packaging bag consists of opposing surface laminates and back laminates. The packaging bag has a sealing portion that seals the peripheral edges of the surface laminate and the back laminate, and a storage portion for containing the contents. The surface laminate and the back laminate each have a laminated structure comprising a base layer, an adhesive layer, and a sealant layer in this order. The aforementioned substrate layer is made of polyethylene film, The sealant layer contains a polyethylene resin, In the above process, a laser beam is irradiated onto the packaging bag to volatilize a portion of the surface laminate and the back laminate, thereby forming a linear void that will serve as the opening line. The packaging bag after the above process has a fused portion where the sealant layer of the surface laminate and the back laminate are fused together at a position overlapping with the linear void, A method for manufacturing a packaging bag, wherein the width of the fused portion is 5 to 100 μm.

2. A packaging bag consisting of opposing surface laminates and back laminates, It has a sealing portion that seals the peripheral edges of the surface laminate and the back laminate, a storage portion for containing contents, and an opening line to assist in opening, The surface laminate and the back laminate each have a laminated structure comprising a base layer, an adhesive layer, and a sealant layer in this order. The aforementioned substrate layer is made of polyethylene film, The sealant layer contains a polyethylene resin, The surface laminate and the back laminate each have a linear void between the base material layer and the sealant layer that forms the intended opening line. The packaging bag has a fused portion where the sealant layer of the surface laminate and the back laminate are fused together at a position overlapping with the linear void, A packaging bag in which the width of the fused portion is 5 to 100 μm.

3. The packaging bag according to claim 2, wherein the surface laminate and the back laminate each further comprise an intermediate layer made of polyethylene film between the base material layer and the sealant layer.

4. The packaging bag according to claim 2 or 3, wherein the surface laminate and the back laminate each further comprise a vapor-deposited layer.

5. The packaging bag according to claim 2 or 3, wherein the opening line is a solid line or a dashed line.

6. The packaging bag according to claim 2 or 3, wherein the opening line is a straight line or a curved line.

7. The packaging bag according to claim 2 or 3, wherein the opening line is formed in the sealing portion.

8. The packaging bag according to claim 2 or 3, wherein three opening lines are formed on the surface laminate and the back laminate, respectively.

9. The packaging bag according to claim 2 or 3, further comprising a zipper mechanism between the surface laminate and the back laminate.

10. The packaging bag according to claim 2 or 3, wherein the packaging bag is a three-sided seal bag.

11. The packaging bag is a self-standing packaging bag formed by heat-sealing the bottom tape and a pair of main body parts, The packaging bag according to claim 2 or 3, wherein the pair of main body parts consist of the surface laminate and the back laminate.

12. The packaging bag according to claim 2 or 3, wherein the content of the polyethylene resin is 90% by mass or more based on the total amount of the packaging bag.

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