Packaging bag and method for manufacturing a packaging bag

Abstract

The present invention provides a two-compartment, separable packaging bag and a method for manufacturing the packaging bag that can suppress a decline in productivity. [Solution] The packaging bag 1 is made of a film 2 mainly composed of polyethylene resin and having at least two layers, a sealant layer L3 and a base layer L1, with the outer circumference strongly bonded with the sealant layer L3 on the inside, and has an easily peelable portion 4 with weaker adhesive force than the outer circumference of the packaging bag 1, and the inside of the packaging bag 1 is divided into two sealed spaces, a first storage portion 1a and a second storage portion 1b, by the easily peelable portion 4. The easily peelable portion 4 has a weakly welded portion 5 in which the sealant layers are continuously welded to each other by laser irradiation along a line segment connecting two points on the outer circumference, and the easily peelable portion 4 is formed by one or more weakly welded portions 5.

Description

[Technical Field]

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

[0002] Generally, face pack masks are used by impregnating a hydrophilic sheet, such as nonwoven fabric, with lotion. As a portable packaging bag for such face pack masks, a design has been proposed in which the portable packaging bag is divided into two compartments by a peel-off adhesive section, with the folded face pack mask stored in one compartment and the lotion in the other compartment. By applying pressure from the outside of the portable packaging bag to at least one of these compartments, the peel-off adhesive section is separated, causing the lotion in the other compartment to impregnate the face pack mask in the first compartment (see, for example, Patent Document 1). Furthermore, a two-compartment separation bag has also been proposed that has a partition in the approximate center, allowing two types of contents to be stored separately. The partition is formed by heat-sealing the film constituting the upper and lower surfaces of the bag with an easily peelable strip tape in between. The heat-sealed portion is approximately strip-shaped parallel to the strip tape and has a narrow section in one part. The portion of the heat-sealed portion excluding the narrow section is also located in the area where the easily peelable strip tape is not sandwiched. As a result, the partition is less likely to peel off even when external pressure is applied when the bag is laid flat, and the bag can be carried stably during transport or handling without the partition accidentally connecting. (See, for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2002-12273 [Patent Document 2] Japanese Patent Publication No. 2010-83567 [Overview of the project] [Problems that the invention aims to solve]

[0004] The two-compartment, separate packaging bag described above, which allows two contents to be mixed inside the bag, requires specialized components, such as a specially designed, easily removable tape or sealant for the weakly bonded area. Furthermore, it requires a dedicated bag-making machine for production, resulting in poor productivity from the perspective of production efficiency and cost. Therefore, this invention has been made in view of the above-mentioned conventional problems, and aims to provide a two-compartment separation type packaging bag and a method for manufacturing the packaging bag that can suppress a decrease in productivity. [Means for solving the problem]

[0005] According to one aspect of the present invention, a packaging bag is provided which is made of a film mainly composed of polyethylene resin and having at least two layers, a sealant layer and a base layer, with the outer periphery strongly bonded with the sealant layer on the inside, and which has an easily peelable portion with weaker adhesive force than the outer periphery, and the inside is divided into two spaces by the easily peelable portion in a watertight and airtight manner, and the easily peelable portion has at least one weakly welded portion in which the sealant layers are continuously welded together by laser irradiation along a line segment connecting two points on the outer periphery.

[0006] Furthermore, according to another aspect of the present invention, a method for manufacturing a packaging bag is provided, comprising the steps of: forming a bag having an opening by strongly bonding the outer periphery of a film mainly composed of polyethylene resin having at least two layers, a sealant layer and a base layer, with the sealant layers facing each other and a portion open; continuously irradiating the bag with a laser from one side along a line segment connecting one point on the outer periphery opening and another point on the outer periphery to continuously weld the sealant layers together to form a weakly welded portion, forming one or more weakly welded portions to form an easily peelable portion with weaker adhesive force than the outer periphery, thereby forming two spaces inside the bag, each communicating with the opening and divided into watertight and airtight sections; and arranging the contents to be contained in each of the two spaces from the opening, and then strongly bonding the opening. [Effects of the Invention]

[0007] According to one aspect of the present invention, it is possible to suppress the decrease in productivity of two-compartment separate packaging bags. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1(a) is a plan view showing an example of a packaging bag according to one embodiment of the present invention, and Figure 1(b) is a cross-sectional view of AA' of Figure 1(a). [Figure 2] This is a cross-sectional view showing an example of the film's structure. [Figure 3] This is an explanatory diagram for describing the laser irradiation method. [Figure 4] This is a cross-sectional view showing an example of another film configuration. [Figure 5] This is an explanatory diagram showing an example of a packaging bag manufacturing method. [Modes for carrying out the invention]

[0009] The embodiments of this technology will be described below with reference to the drawings. Here, the drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of the thickness of each layer, etc., may differ from reality. Furthermore, the embodiments shown below illustrate configurations for realizing the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the materials, shapes, and structures of the components described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims described in the patent claims.

[0010] [Packaging bag] Figure 1 is a plan view (Figure 1(a)) and a cross-sectional view AA' of the plan view of Figure 1(a) showing an example of a packaging bag 1 according to an embodiment of the present invention (Figure 1(b)). As shown in Fig. 1, the packaging bag 1 has a rectangular shape formed by overlapping two films 2. The outer peripheral ends of the films 2 are strongly adhered to each other by heat sealing or the like, forming a strong adhesion portion 3. Further, an easily peelable portion 4 is formed inside the packaging bag 1, and by the easily peelable portion 4, the inside of the packaging bag 1 is divided into two spaces, namely a first accommodation portion 1a and a second accommodation portion 1b, in a water-tight and air-tight manner.

[0011] First, the film 2 will be described. 〔Film〕 Fig. 2 is a cross-sectional view schematically showing the film 2. The film 2 has a laminated structure including a base material layer L1, an adhesive layer L2, and a sealant layer L3 in this order.

[0012] 〔Base material layer〕 The base material layer L1 is made of a stretched polyethylene film or an unstretched polyethylene film. Here, the unstretched polyethylene film refers to a polyethylene film having a structure in which spherical crystals (spherulites) of about 10 to 100 μm composed of randomly folded polyethylene molecular chains are connected by amorphous molecules without undergoing stretching treatment during film formation. The stretched polyethylene film refers to a polyethylene film having an array structure formed by stretching treatment during film formation.

[0013] The content of the polyethylene-based resin in the base material layer L1 may be 50% by mass or more, may be 80% by mass or more, or may be 100% by mass based on the total amount of the base material layer L1. Using a polyethylene-based resin as the material of the base material layer L1 is preferable from the viewpoint of recyclability. Also, the higher the content of the polyethylene-based resin in the base material layer L1, the better the recyclability. The polyethylene-based resin contained in the base material layer L1 may be an 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, or the like.

[0014] The density of the polyethylene-based resin contained in the base material layer L1 is 0.910 g / cm3 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 heat sealing is performed to form the film 2 into a bag shape, 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, the printability is good when an ink layer is formed 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.

[0015] 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.

[0016] 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 within the film 2 tends to be good. The molecular orientation degree can be measured using a molecular orientation meter.

[0017] The thermal shrinkage rate of the base 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 layer L1 is within the above range, it is easier to suppress the stretching and wrinkling of the base layer L1 during roll processing, and it is also easier to suppress the occurrence of cracks in the transparent vapor deposition layer when a transparent vapor deposition layer is provided on the base layer L1.

[0018] 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.

[0019] The thickness of the base layer L1 is not particularly limited. Depending on the application, the thickness of the base layer L1 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. 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, as long as it does not impair barrier performance, or a coating layer such as an easy-adhesion layer may be provided.

[0020] 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.

[0021] [Adhesive layer] The adhesive used to form the adhesive layer L2 can be selected according to the bonding method, but urethane-based adhesives, polyester-based adhesives, etc., can be used. By providing the adhesive layer L2, the adhesion between the base material layer L1 and the sealant layer L3 is improved, making delamination less likely and maintaining the pressure resistance and impact resistance of the packaging bag 1. From the viewpoint of forming the easily peelable portion 4 described later, it is preferable that the adhesive layer L2 be made of a material with low laser light absorption. The low laser light absorption of the adhesive layer L2 allows the laser light irradiated from the substrate layer L1 to reach the side of the sealant layer L3 opposite to the adhesive layer L2, thereby obtaining a good easily peelable portion 4 with appropriate welding strength.

[0022] Furthermore, it is preferable that the adhesive layer L2 does not contain chlorine. By not including chlorine in the adhesive layer L2, it is possible to prevent discoloration of the adhesive or recycled resin after recycling, and to prevent odor generation due to heat treatment. From an environmental perspective, it is preferable that the adhesive layer L2 be made from biomass material. From an environmental perspective, it is preferable that the adhesive does not contain solvents. The thickness of the adhesive layer L2 may be, for example, 0.1 to 10 μm, 0.1 to 5.0 μm, or 0.2 to 2.0 μm.

[0023] [Sealant layer] 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.

[0024] 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 density of the sealant layer L3 is 0.925 g / cm³. 3 Less than (more preferably 0.900~0.920 g / cm³) 3 It is preferable that it be composed of a polyethylene-based resin. A specific example is linear low-density polyethylene (LLDPE).

[0025] The sealant layer L3 may also contain mechanically recycled polyethylene made from used polyethylene products or resin (so-called burrs) generated during the manufacturing process of polyethylene products. From the viewpoint of recyclability, the total content of polyethylene-based resin in film 2 is preferably 90% by mass or more, based on the total mass of film 2. From the viewpoint of achieving a higher degree of monomaterialization, the polyethylene-based resin content in film 2 is more preferably 92% by mass or more, and even more preferably 95% by mass or more.

[0026] Next, we will explain packaging bag 1. [Strong adhesive part] As shown in Figure 1, the packaging bag 1 is formed into a bag shape by overlapping the sealant layers L3 of the film 2 so that they face each other, and bonding the outer circumference of all four sides by heat sealing or the like. The strong adhesive portion 3 bonded by heat sealing or the like does not peel off under normal use conditions where no external pressure is applied, such as when carrying or transporting the packaging bag 1, and has sufficient adhesive strength to prevent the heat-sealed portion on the outer circumference of the packaging bag 1 from peeling off when external pressure is applied to the packaging bag 1 for the purpose of connecting the first storage portion 1a and the second storage portion 1b described later.

[0027] [Easily peelable area] As shown in Figure 1, the easily detachable portion 4 is provided parallel to the strongly adhesive portions 3 on two opposing sides and near the center of these two opposing sides.

[0028] The peelable portion 4 is formed by one or a plurality of weakly welded portions 5. The weakly welded portion 5 is laser welded by continuously performing laser irradiation from the outermost layer side of the front film 2a side or the back film 2b side toward the other film 2 side in a state where the sealant layers L3 of the film 2 face each other. The laser irradiation is performed, for example, by CO 2 laser. Specifically, by continuously performing laser irradiation along a line segment connecting two points on the outer periphery of the film 2, the sealant layers L3 of the film 2 are continuously welded to form the weakly welded portion 5, and the interior of the packaging bag 1 is watertightly and airtightly divided into two compartments (the first storage portion 1a and the second storage portion 1b) by this weakly welded portion 5.

[0029] The peelable portion 4 has peelability. By applying an external pressure to at least one of the first storage portion 1a and the second storage portion 1b, such as pressing and compressing the first storage portion 1a and the second storage portion 1b, or both of them, from the outside of the packaging bag 1, the pressure inside at least one of the first storage portion 1a and the second storage portion 1b increases, whereby the sealant layers L3 of the peelable portion 4 are peeled off from each other, and it has an adhesive strength such that the first storage portion 1a and the second storage portion 1b communicate with each other. By adjusting the number of the weakly welded portions 5 constituting the peelable portion 4, the interval between the weakly welded portions 5, that is, the width of the peelable portion 4, etc., the peelable portion 4 is adjusted to have a desired peelability.

[0030] When providing a plurality of weakly welded portions 5, they may be provided so as not to overlap in a plan view. For example, a plurality of weakly welded portions 5 may be provided in parallel along a single line segment connecting two points on the outer periphery of the film 2. The laser irradiation when forming the weakly welded portion 5 is performed, for example, under the conditions of a wavelength of 9.2 to 10.8 μm, a scan speed of 100 to 1000 mm / second, and an output of 20 to 80 W.

[0031] When forming multiple weakly welded sections 5, laser irradiation may be performed only from the back film 2b side, as shown in Figure 3(a), or only from the front film 2a side. Alternatively, it may be performed from both the front film 2a side and the back film 2b side, as shown in Figure 3(b). Note that Figure 3 corresponds to the easily peelable section 4 portion of the cross-sectional view shown in Figure 1(b). Also, Figure 3 shows a case where each film has a 5-layer structure including a base layer L1 and a sealant layer L3.

[0032] When forming multiple weakly welded sections 5, if laser irradiation is performed from both the front film 2a side and the back film 2b side as shown in Figure 3(b), the laser irradiation positions should not overlap in a plan view as shown in Figure 3(b). In other words, since polyethylene resin does not easily absorb laser light, the laser light penetrates one film 2 and reaches the sealant layer L3 of the other film 2. If laser irradiation is performed from both the front film 2a side and the back film 2b side, and the laser irradiation positions overlap in a plan view, the laser light irradiated from the front film 2a side and the back film 2b side will penetrate the front film 2a and the back film 2b respectively and reach the other film, causing the sealant layer L3 of both the front film 2a and the back film 2b to melt and become strongly welded, making it impossible to easily peel them off even by pressing with your hand. Therefore, by performing laser irradiation in such a way that the irradiation position of the laser beam from the front film 2a side and the irradiation position of the laser beam from the back film 2b side do not overlap in a plan view, strong welding of the sealant layers L3 to each other is suppressed.

[0033] As shown in Figure 3(a), when laser irradiation is performed from only the front film 2a side or only the back film 2b side, for the same reason, it is preferable to irradiate in such a way that the laser beams do not overlap in a plan view when forming multiple weakly welded parts 5.

[0034] [Variation] In the above embodiment, the case in which the film 2 is formed with a laminated structure consisting of a sealant layer L3, an adhesive layer L2, and a base layer L1 made of stretched polyethylene or unstretched polyethylene was described, but the embodiment is not limited to this.

[0035] For example, the laminated structure of film 2 may be further provided with at least one of a transparent vapor deposition layer L4, an ink layer L5, and an intermediate layer L6, as shown in Figure 4(a). Laminated structures may be formed by laminating a sealant layer L3, an adhesive layer L2, a transparent vapor deposition layer L4, and a substrate layer L1 in this order (Figure 4(b)), a laminated structure may be formed by laminating a sealant layer L3, an adhesive layer L2, a transparent vapor deposition layer L4, a substrate layer L1, and an ink layer L5 in this order (Figure 4(c)), or a laminated structure may be formed by laminating a sealant layer L3, an adhesive layer L2, a transparent vapor deposition layer L4, an intermediate layer L6, an adhesive layer L2a, an ink layer L5, and a substrate layer L1 in this order. The laminated structure may be as follows: (Figure 4(d)), a laminated structure in which a sealant layer L3, an adhesive layer L2, a transparent vapor deposition layer L4, an intermediate layer L6, an ink layer L5, an adhesive layer L2a, and a base layer L1 are stacked in this order (Figure 4(e)), a laminated structure in which a sealant layer L3, an adhesive layer L2, a transparent vapor deposition layer L4, an intermediate layer L6, an adhesive layer L2a, a base layer L1, and an ink layer L5 are stacked in this order (Figure 4(f)), a laminated structure in which a sealant layer L3, an adhesive layer L2a, an intermediate layer L6, a transparent vapor deposition layer L4, an adhesive layer L2, and a base layer L1 are stacked in this order (Figure 4(g)), or a laminated structure in which a sealant layer L3, an adhesive layer L2a, an ink layer L5, an intermediate layer L6, an ink layer L4, an adhesive layer L2, and a base layer L1 are stacked in this order (Figure 4(h)).

[0036] In the film 2 having the laminated structure shown in Figures 4(a) to (h), the base layer L1 may be a layer made of stretched polyethylene or a layer made of unstretched polyethylene. Furthermore, the film 2 may have a laminated structure that does not include a transparent vapor deposition layer L4.

[0037] Furthermore, film 2 does not necessarily have to include adhesive layers L2 and L2a. Furthermore, it is preferable that the layers provided between the base layer L1 and the sealant layer L3, and the ink layer L5 provided on the side of the base layer L1 opposite to the sealant layer L3, be made of a material with low laser light absorption, from the viewpoint of forming the easily peelable portion 4 described later. By having low laser light absorption in each of these layers, the laser light irradiated from the base layer L1 side can reach the side of the sealant layer L3 opposite to the adhesive layers L2 and L2a, and an easily peelable portion 4 with appropriate welding strength can be obtained.

[0038] [Transparent vapor deposition layer] Examples of constituent materials for the transparent vapor deposition layer L4 include inorganic oxides such as silicon dioxide, magnesium oxide, and tin oxide. From the viewpoint of laser light absorption, it is preferable to use a material with low laser light absorption, excluding aluminum oxide. By using the transparent vapor deposition layer L4, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the laminate.

[0039] The O / Si ratio of the transparent 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 transparent 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 transparent vapor-deposited layer L4 when laminating the adhesive layer L2. In addition, even after forming the packaging bag 1, 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 transparent vapor-deposited layer L4 can easily follow the above shrinkage, and a decrease in barrier properties can be suppressed. From the viewpoint of obtaining these effects more fully, the O / Si ratio of the transparent 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.

[0040] The O / Si ratio of the transparent vapor-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.

[0041] The thickness of the transparent 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, the thickness of the transparent vapor-deposited layer L4 is more preferably between 20 nm and 40 nm.

[0042] The transparent 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.

[0043] 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.

[0044] [Ink layer] By providing a reverse-printed ink layer L5, the design and text of the ink layer L5 can be recognized from the surface side of the packaging bag 1. Furthermore, from the viewpoint of preventing discoloration or odor generation of the ink layer L5 when it is remelted, it is preferable to use a chlorine-free printing ink for the ink layer L5. In addition, from the viewpoint of environmental consideration, it is preferable to use biomass materials for the compounds contained in the printing ink.

[0045] [Middle class] The intermediate layer L6 mainly contains polyethylene resin. The intermediate layer L6 is preferably composed of a polyethylene film, and the polyethylene film is preferably unstretched. Because the polyethylene film is unstretched, the resin has almost no orientation, making it easy to stretch and difficult to break under external stresses such as tension and shear. The thickness of the intermediate layer L6 is, for example, 5 to 800 μm, and may be 5 to 500 μm or 10 to 50 μm.

[0046] The polyethylene resin content in the intermediate layer L6 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 L6. Using polyethylene resin as the material for the intermediate layer L6 is preferable from the viewpoint of recyclability. Furthermore, the higher the polyethylene resin content in the intermediate layer L6, the better the recyclability.

[0047] The polyethylene resin contained in the intermediate layer L6 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. The melting point of the intermediate layer L6 is preferably 120°C or higher, and more preferably 125°C or higher. Examples of polyethylene constituting the intermediate layer L6 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.

[0048] The intermediate layer L6 may contain components other than polyethylene resin. Specifically, it 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. If the film 2 includes a reverse-printed ink layer L5 and a transparent vapor-deposited layer (barrier layer) L4, it is preferable to provide an intermediate layer L6.

[0049] [Adhesive layer] The adhesive layer 2a can be constructed in the same way as adhesive layer 2. In other words, the adhesive that makes up adhesive layer 2a can be selected according to the bonding method, and the thickness of adhesive layer L2a may also be the same as that of adhesive layer 2.

[0050] [Method of manufacturing packaging bags] Next, the manufacturing method of the packaging bag 1 containing the contents will be explained with reference to Figure 5. This section describes the process for manufacturing a roughly rectangular packaging bag, but the shape of the packaging bag 1 is not limited to a rectangle; it is not restricted as long as it can form an easy-peel section 4.

[0051] First, the film 2 is bonded together to form a bag. Two identical rectangular films 2 may be layered and their three outer edges bonded together, or a rectangular film 2 may be folded in half and its two outer edges bonded together. At this time, the bond should be strong enough so that it does not peel off when external pressure is later applied to the packaging bag 1. This forms a bag 1' with one side open (Figure 5(a)). For example, by performing heat sealing, strong adhesive portions 3 are formed on the outer edges of three sides of the bag 1'.

[0052] Next, as shown in Figure 5(b), an easily peelable portion 4 is formed near the center of the left and right strong adhesive portions 3R and 3L, parallel to these strong adhesive portions 3R and 3L. Specifically, as shown in Figure 5(b), laser irradiation is performed from one side of the front and back films 2 toward the other side, and the laser irradiation is performed continuously along a line segment connecting one point on the end of the opening M side to one point on the strong adhesive portion 3 at the other end, parallel to the strong adhesive portions 3R and 3L, to form a weakly welded portion 5a. Similarly, the laser irradiation is performed continuously from the end of the opening M side to a position overlapping with the strong adhesive portion 3 at the other end, parallel to the strong adhesive portions 3R and 3L, i.e., parallel to the weakly welded portion 5a, to form a weakly welded portion 5b, and similarly to form a weakly welded portion 5c, thereby forming a total of three weakly welded portions 5a to 5c.

[0053] When laser irradiation is performed, the number of weakly welded sections 5a (one or more) and the interval between laser irradiations (i.e., the width of the easily detachable section 4) are adjusted so that when external pressure is applied to the packaging bag 1 for the purpose of later removing the easily detachable section 4, the easily detachable section 4 will peel off easily. However, when external pressure is not applied to the packaging bag 1 with the intention of removing the easily detachable section 4, the easily detachable section 4 will not peel off, and the adhesive strength will be such that watertightness and airtightness are maintained. In Figure 5(b), the easily detachable section 4 (Figure 5(c)) is formed by creating three weakly welded sections 5 (5a to 5c).

[0054] As a result, two spaces are formed inside the bag: a first storage section 1a and a second storage section 1b, which are separated into a watertight and airtight section by the easy-peel section 4. In this state, the objects to be stored are placed in the first storage section 1a and the second storage section 1b from the side of the opening M. Subsequently, the opening M is heat-sealed to ensure strong adhesion (Figure 5(d)).

[0055] This creates a packaging bag 1 in which the contents to be contained are sealed in a watertight and airtight manner in the first containment section 1a and the second containment section 1b, respectively. The packaging bag 1 is provided with an easy-peel section 4 inside, and is divided into two spaces that are watertight and airtight by the easy-peel section 4, so that the contents in the first storage section 1a and the contents in the second storage section 1b do not mix.

[0056] Furthermore, the easily detachable portion 4 is designed to be easily peeled off when pressure is applied to the packaging bag 1 from the outside, such as by pressing down on it, which increases the pressure inside the bag. However, when no external pressure is applied to the bandage bag 1, the easily detachable portion 4 will not peel off due to the adhesive strength. Therefore, the possibility of the easily detachable portion 4 peeling off during transport is low, and since the outer edge of the packaging bag 1 is strongly bonded, even if the easily detachable portion 4 peels off, the possibility of the contents leaking out of the packaging bag 1 is low.

[0057] [Instructions for using the contained items] Examples of contents that can be contained in packaging bag 1 include those that require hygienic mixing of two contents, such as cosmetics, food, and pharmaceuticals. Specifically, examples include powder and solution for cosmetic packs, roasted sesame seeds and dressing, compressed wet wipes and purified water, two-part curing adhesives, oily and aqueous solutions that easily separate, drugs and physiological saline (infusion packs), and sheet masks (cosmetics) that involve mixing two types of beauty serums.

[0058] When using the contents of the packaging bag 1, the first containment section 1a or the second containment section 1b is pressed from the outside of the packaging bag 1 with a hand or the like to release the adhesive of the easily release section 4. Because the easily release section 4 is easily released, pressing it increases the pressure inside the first containment section 1a and the second containment section 1b, and the flow force of the contents causes the easily release section 4 to peel off, connecting the first containment section 1a and the second containment section 1b, and mixing the contents of the first containment section 1a and the contents of the second containment section 1b.

[0059] The user can mix the contents of the first storage section 1a and the second storage section 1b from above the packaging bag 1 without touching the contents themselves. Then, by making a cut in the strongly adhesive portion 3 of the packaging bag 1 and removing the contents, the mixture of the contents of the first storage section 1a and the contents of the second storage section 1b can be removed.

[0060] [Variation] The easily detachable portion 4 does not necessarily have to be located near the center of the left and right strong adhesive portions 3, or parallel to them. It may be located closer to either side of the left and right strong adhesive portions 3, and it does not necessarily have to be located parallel to the left and right strong adhesive portions 3.

[0061] Furthermore, the easily detachable portion 4 does not need to be a straight line; it can be provided in any shape depending on the shape of the contents, the shape of the packaging bag 1, etc., and may, for example, be provided in a curved shape. In other words, when creating the weakly welded portion 5, it is not necessary to irradiate the laser in a straight line; the laser irradiation may be performed in accordance with the desired shape of the easily detachable portion 4.

[0062] Furthermore, although Figure 1 shows that the first storage section 1a and the second storage section 1b have similar, roughly rectangular shapes, they do not have to be rectangular or similar in shape. The first storage section 1a and the second storage section 1b can have any shape, and it is sufficient that they are connected by the easy-peel section 4. In this case, when laminating the film 2, openings for accommodating the contents may be individually provided in the first storage section 1a and the second storage section 1b.

[0063] [Effects of the Embodiment] In packaging bag 1, an easy-peel section 4 that divides the inside of the packaging bag into two is formed by creating one or more weakly welded sections 5 by laser irradiation. Therefore, unlike conventional products, there is no need to use separate special materials such as specially designed easy-peel tape or special sealant, and the easy-peel section 4 can be formed without the need for a special bag-making machine. As a result, packaging bag 1 can be realized without the cost increase or decrease in production efficiency associated with providing the easy-peel section 4, and the decrease in productivity can be suppressed compared to conventional two-compartment separated packaging bags.

[0064] Furthermore, since film 2 is formed primarily from polyethylene resin, packaging bag 1 can be formed primarily from polyethylene resin, making it possible to obtain packaging bag 1 with excellent recyclability. Furthermore, when forming multiple weakly welded sections 5, if laser irradiation is performed only from the outermost layer side of one of the films 2, or if some weakly welded sections 5 are formed by laser irradiation from one side of the film 2 and other weakly welded sections 5 are formed by laser irradiation from the other side of the film 2, the irradiation is performed so that the irradiation positions of the laser beams do not overlap in a plan view. This suppresses strong welding of the films 2 together by laser irradiation, and makes it possible to easily form easily peelable sections 4 with easy peelability.

[0065] Furthermore, by forming the film 2 from a laminated structure consisting of a sealant layer L3 and a substrate layer L1, with a transparent vapor-deposited layer further provided between them, the gas barrier properties against water vapor, oxygen, etc. can be improved. Furthermore, by forming the film 2 from a laminated structure with an intermediate layer L6 mainly composed of polyethylene resin between the sealant layer L3 and the base material layer L1, it is possible to realize a packaging bag 1 with excellent recyclability even when the intermediate layer L6 is provided. In particular, by making the main component of the intermediate layer L6 an unstretched polyethylene resin, it is possible to realize a packaging bag 1 that is easily stretched and less prone to tearing under external stresses such as tension and shear.

[0066] Furthermore, by configuring the film 2 to include a reverse-printed ink layer L5, patterns, text, etc., can be recognized from the front side of the packaging bag 1. Furthermore, by ensuring that the total content of polyethylene-based resin in film 2 is 90% by mass or more, a packaging bag 1 suitable from the viewpoint of recyclability can be realized.

[0067] Furthermore, a film 2, mainly composed of polyethylene resin and having at least two layers, a sealant layer L3 and a base layer L1, is formed by placing the sealant layers L3 facing each other, leaving a portion open, and strongly bonding the outer periphery to form a bag body 1' with an opening M. Laser irradiation is performed from one side of the bag body 1' to form one or more weakly welded sections 5, thereby forming easily peelable sections 4 that have weaker adhesive strength than the strongly bonded sections 3 and can be easily peeled off by external pressure, thus dividing the inside of the bag body into two. After placing the contents into each of the two divided spaces inside the bag body 1', the opening M is strongly bonded, making it easy to realize a two-compartment separate packaging bag 1. Furthermore, when forming multiple weakly welded sections 5, that is, when forming multiple weakly welded sections 5 by irradiating with a laser from only one side of the film 2, or when forming some weakly welded sections 5 by irradiating with a laser from one side of the film 2 and other weakly welded sections 5 by irradiating with a laser from the other side of the film 2, the irradiation positions do not overlap in a plan view, that is, the multiple weakly welded sections 5 do not overlap or intersect, so that the easily peelable wall peelable sections 4 can be easily formed. [Examples]

[0068] Examples and comparative examples of the packaging bags according to the present invention are described below. However, the present invention is not limited to the following embodiments.

[0069] <Examples> (Example 1) Two films of roughly identical, roughly rectangular shape were prepared, each consisting of a laminated structure in which a base layer, an adhesive layer (first adhesive layer), an intermediate layer, an adhesive layer (second adhesive layer), and a sealant layer are stacked in that order.

[0070] The structure of each layer is as follows: 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 Interlayer: Unoriented HDPE film (thickness 32 μm, density 0.948 g / cm³) 3 (Melting point 135℃) Second adhesive layer: Urethane-based adhesive Sealant layer: LLDPE (thickness 100 μm, density 0.916 g / cm³) 3 (MFR 7g / 10 min, melting point 104℃) Next, the two films were overlapped, aligning their four corners, and the outer edges of three sides were strongly bonded together, for example, by heat sealing, to form a bag with an opening.

[0071] Next, laser irradiation was performed from one side of the film, followed by laser irradiation from the other side, forming a total of five weakly welded areas: two from the front side and three from the back side, as shown in Figure 3(b). At this time, the laser irradiation was performed so that the irradiation positions did not overlap in a plan view, and the weakly welded areas were formed alternately from the front side and the back side in a plan view. In addition, with the opening facing upwards in a plan view, the laser irradiation was performed passing approximately near the center of the left and right strong adhesive areas, parallel to the left and right strong adhesive areas, from the upper end of the opening to a position overlapping with the lower end strong adhesive area, thereby dividing the opening into approximately two equal parts, and the bag-like portion inside the packaging bag into approximately two equal parts. As a result, an easily peelable area consisting of five weakly welded areas was formed, and the opening was divided into two by this easily peelable area, forming a first and second storage area inside the bag-like portion, each consisting of two spaces communicating with the opening.

[0072] Laser irradiation was performed under the following conditions. Laser: LP-430U (product name, manufactured by Panasonic Corporation) Laser light power: 80% Scanning speed: 500mm / s Laser light wavelength: 10.6 μm Next, two different types of contents were placed in the first and second storage compartments through their respective openings. Then, the two openings were strongly sealed, for example, by heat sealing, to create a packaging bag with a strongly sealed outer perimeter and two sealed spaces, each containing the contents. The container held two different types of substances: cosmetic A and cosmetic B, whose stability is compromised when mixed.

[0073] (Example 2) In the packaging bag of Example 1, the packaging bag was created using the same procedure as in Example 1, except that when laser irradiation was performed, only one of the two films (for example, the film that becomes the front side of the packaging bag) was irradiated to form five weakly welded areas. (Example 3) In the packaging bag of Example 1, the packaging bag was created using the same procedure as in Example 1, except that when laser irradiation was performed, the irradiation was performed only from the other film of the two films (for example, the film on the back of the packaging bag) to form five weakly welded sections.

[0074] <Comparative Example> (Comparative Example 1) The packaging bag of Example 1 was prepared using the same procedure as in Example 1, except that the materials of the base layer, intermediate layer, and sealant layer constituting the film were different, and the position of the weakly welded area was different. The structure of each layer is as follows: Base layer: Stretched nylon film (ONY) (manufactured by Gyosei Japan Co., Ltd., GQ91-A, 15 μm thickness) First adhesive layer: Urethane-based adhesive Intermediate layer: Aluminum-deposited polyester film (VMPET) (manufactured by Oike Kogyo Co., Ltd., Tetrilite EXE, 12 μm thick) Second adhesive layer: Urethane-based adhesive Sealant layer: Linear low-density polyethylene film (LLDPE) (manufactured by RM Tohcello Co., Ltd., TUX-MC-S, 100 μm thick) Furthermore, when performing laser irradiation, the laser was irradiated from one side of the film and from the other side. At this time, the laser irradiation was performed so that the irradiation position of the laser beam irradiated from the front side and the irradiation position of the laser beam irradiated from the back side overlapped in a plan view. The laser irradiation was performed under the same conditions as in Examples 1 to 3.

[0075] (Comparative Example 2) In the packaging bag of Comparative Example 1, when laser irradiation was performed, the laser was irradiated from one side of the film and from the other side, but the laser irradiation was performed in such a way that the laser irradiation positions did not overlap in a plan view. Otherwise, the packaging bag was made using the same procedure as in Comparative Example 1. (Comparative Example 3) In the packaging bag of Comparative Example 1, the packaging bag was created using the same procedure as in Comparative Example 1, except that when laser irradiation was performed, the irradiation was performed from only one of the two films (for example, the film that becomes the front side of the packaging bag) so that they did not overlap in a plan view.

[0076] (Comparative Example 4) In the packaging bag of Comparative Example 1, the packaging bag was created using the same procedure as in Comparative Example 1, except that when laser irradiation was performed, the irradiation was performed only from the other film of the two films (for example, the film on the back of the packaging bag) so that they did not overlap in a plan view. (Comparative Example 5) In the packaging bag of Example 1, when laser irradiation was performed, the laser was irradiated from one side of the film and from the other side, but the packaging bag was created using the same procedure as in Example 1, except that the laser irradiation was performed so that the laser irradiation positions overlapped in a plan view.

[0077] [Evaluation Method] The packaging bags of Examples 1-3 and Comparative Examples 1-5 were evaluated. (Presence or absence of laser welding) When laser irradiation was performed to form a simple welded area, it was confirmed whether the sealant layers were welded together. Whether or not welding occurred was confirmed by observing the cross-sections of one film (surface laminate) and the other film (backside laminate) in the area where the laser irradiation was performed and a simple welded area was presumably formed (observation magnification: 500x). (The amount of contents that come out when pressed) In the packaging bag, one of the compartments was pressed, causing the simple welded joint to separate and the two compartments to connect. The extent to which the contents of one compartment protruded into the other compartment was then checked. The extent of protrusion was confirmed by five monitors pressing the center of one of the compartments. (Recyclability) A "○" indicates that the packaging bag is made of a single material, while a "×" indicates that it contains multiple components.

[0078] [Evaluation Results] The evaluation results for the packaging bags of the examples and comparative examples are shown in Table 1.

[0079] [Table 1]

[0080] As shown in Table 1, in Comparative Examples 1-4, where the packaging bags included an aluminum-deposited polyester film (VMPET) as an intermediate layer, the laser light was absorbed by the intermediate layer, preventing the laser light from reaching the sealant layer. As a result, the sealant layers on the front and back sides did not fuse together even after laser irradiation. In Examples 1-3 and Comparative Example 5, where each layer is formed from a single material, the laser light was less absorbed by the film, allowing the laser light to reach the sealant layer of the other film, and it was confirmed that the sealant layers of the two films fused together. Furthermore, when laser irradiation was performed from only one side of the packaging bag, or sequentially from both sides, and the laser irradiation was performed on areas that did not overlap in a plan view (Examples 1-3), it was confirmed that the simply fused area could be easily peeled off by lightly pressing one of the storage compartments, causing the contents in one compartment to flow out to the other compartment. On the other hand, when laser irradiation was performed sequentially from the front and back film sides of the packaging bag, and the laser irradiation was performed at positions that overlapped in a plan view (Comparative Example 5), the laser light irradiated from both sides reached the other film, and the sealant layers were strongly welded together. As a result, even when one side of the packaging bag was strongly pressed, the contents did not leak out to the other side.

[0081] Furthermore, it was confirmed that Examples 1-3, in which the film is formed from a single material, exhibit high recyclability and yield good two-component separation type packaging bags. Furthermore, the present invention can take the following configuration, for example. (1) A packaging bag having at least two layers, a sealant layer and a base layer, and made of a film mainly composed of polyethylene resin, wherein the outer periphery is strongly bonded with the sealant layer facing inward, It has an easily detachable portion with weaker adhesive strength than the outer periphery, and the interior is divided into two spaces by this easily detachable portion, which is watertight and airtight. The packaging bag is characterized in that the easily peelable portion has at least one weakly welded portion in which the sealant layers are continuously welded together by laser irradiation along a line segment connecting two points on the outer circumference. (2) The packaging bag according to (1) above, characterized in that the easily peelable portion is formed by a plurality of weakly welded portions formed along the line segments so as not to overlap in a plan view. (3) The packaging bag according to (1) or (2) above, characterized in that the weakly welded portion is welded by laser irradiation from only the outermost layer side of either of the opposing films. (4) The packaging bag according to (2) above, characterized in that one of the weakly welded portions is welded by laser irradiation from the outermost layer side of one of the films, and the other weakly welded portion is welded by laser irradiation from the outermost layer side of the other film. (5) The packaging bag according to any one of (1) to (4) above, characterized in that the film comprises a transparent vapor deposition layer between the sealant layer and the substrate layer. (6) The packaging bag according to any one of (1) to (5) above, characterized in that the film comprises an intermediate layer mainly composed of polyethylene resin between the sealant layer and the base material layer. (7) The packaging bag according to (6) above, characterized in that the intermediate layer is mainly composed of unstretched polyethylene resin. (8) The packaging bag according to any one of (1) to (7) above, characterized in that the film comprises an ink layer. (9) The packaging bag according to any one of (1) to (8) above, characterized in that the film comprises a reverse-printed ink layer, a transparent vapor-deposited layer, and an intermediate layer. (10) The packaging bag according to any one of the above claims (1) to (9), characterized in that the base material layer is mainly composed of stretched polyethylene resin or unstretched polyethylene resin. (11) The packaging bag according to any one of the above claims (1) to (10), characterized in that the sealant layer is mainly composed of linear low-density polyethylene (LLDPE). (12) The packaging bag according to any one of the above (1) to (11), characterized in that the total content of the polyethylene resin in the film is 90% by mass or more. (13) A process to form a bag having an opening by strongly bonding the outer periphery of a film mainly composed of polyethylene resin, having at least two layers, a sealant layer and a base layer, with the sealant layers facing each other and a portion open, The process involves continuously irradiating the bag body with a laser from one side along a line segment connecting one point on the outer circumference of the opening and another point on the outer circumference, thereby continuously welding the sealant layers together to form a weakly welded portion, forming one or more such weakly welded portions to form an easily peelable portion with weaker adhesive strength than the outer circumference, and forming two spaces inside the bag body, each communicating with the opening and divided into a watertight and an airtight space, The process involves placing the objects to be contained into each of the two spaces through the opening, and then firmly sealing the opening. A method for manufacturing packaging bags, characterized by comprising the following features. (14) The method for manufacturing a packaging bag according to (13) above, characterized in that, in the step of forming the two spaces, one of the weakly welded portions is formed by continuously irradiating the bag with a laser along the line segment from one side of the bag, and the other weakly welded portion is formed by continuously irradiating the bag along the line segment from the other side of the bag, such that the irradiation positions do not overlap in a plan view. [Explanation of Symbols]

[0082] 1 packaging bag 1a First containment area 1b Second containment area 1′ bag body 2 films 2a Front film 2b Backing film 3 Strong adhesive part 4. Easily peelable area 5, 5a~5c Weak weld area L1 base material layer L2, L2a adhesive layer L3 sealant layer L4 Transparent Evaporation Layer L5 インキlayer L6 Intermediate Layer M opening

Claims

1. A packaging bag having at least two layers, a sealant layer and a base layer, and made of a film mainly composed of polyethylene resin, wherein the outer periphery is strongly bonded with the sealant layer facing inward, It has an easily detachable portion with weaker adhesive strength than the outer periphery, and the interior is divided into two spaces by this easily detachable portion, which is watertight and airtight. The packaging bag is characterized in that the easily peelable portion has at least one weakly welded portion in which the sealant layers are continuously welded together by laser irradiation along a line segment connecting two points on the outer circumference.

2. The packaging bag according to claim 1, characterized in that the easily peelable portion is formed by a plurality of weakly welded portions formed along the line segments so as not to overlap in a plan view.

3. The packaging bag according to claim 1 or 2, characterized in that the weakly welded portion is welded by laser irradiation from only the outermost layer side of either of the opposing films.

4. The packaging bag according to claim 2, characterized in that one of the weakly welded portions is welded by laser irradiation from the outermost layer side of one of the films, and the other weakly welded portion is welded by laser irradiation from the outermost layer side of the other film.

5. The packaging bag according to claim 1 or 2, characterized in that the film comprises a transparent vapor-deposited layer between the sealant layer and the substrate layer.

6. The packaging bag according to claim 1 or 2, characterized in that the film comprises an intermediate layer mainly composed of polyethylene resin between the sealant layer and the base material layer.

7. The packaging bag according to claim 6, characterized in that the intermediate layer is mainly composed of unstretched polyethylene resin.

8. The packaging bag according to claim 1 or 2, characterized in that the film comprises an ink layer.

9. The packaging bag according to claim 1 or 2, characterized in that the film comprises a reverse-printed ink layer, a transparent vapor-deposited layer, and an intermediate layer.

10. The packaging bag according to claim 1 or 2, characterized in that the base material layer is mainly composed of stretched polyethylene resin or unstretched polyethylene resin.

11. The packaging bag according to claim 1 or 2, characterized in that the sealant layer is mainly composed of linear low-density polyethylene (LLDPE).

12. The packaging bag according to claim 1 or 2, characterized in that the total content of the polyethylene resin in the film is 90% by mass or more.

13. A process to form a bag having an opening by strongly bonding the outer periphery of a film mainly composed of polyethylene resin, having at least two layers, a sealant layer and a base layer, with the sealant layers facing each other and a portion of it open, The process involves continuously irradiating the bag body with a laser from one side along a line segment connecting one point on the outer circumference of the opening and another point on the outer circumference, thereby continuously welding the sealant layers together to form a weakly welded portion, forming one or more such weakly welded portions to form an easily peelable portion with weaker adhesive strength than the outer circumference, and forming two spaces inside the bag body, each communicating with the opening and divided into a watertight and an airtight space, The process involves placing the objects to be contained into each of the two spaces through the opening, and then firmly sealing the opening. A method for manufacturing packaging bags, characterized by comprising the following features.

14. The method for manufacturing a packaging bag according to claim 13, characterized in that, in the step of forming the two spaces, one of the weakly welded portions is formed by continuously irradiating the bag body with a laser along the line segment from one side of the bag body, and the other weakly welded portion is formed by continuously irradiating the bag body with a laser along the line segment from the other side of the bag body such that the irradiation positions do not overlap in a plan view.

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