Laminate, packaging, method for manufacturing a laminate, and method for manufacturing a packaging

Abstract

The present invention provides laminates, packaging, a method for manufacturing laminates, and a method for manufacturing packaging that suppress variations in the depth of laser processing marks when manufacturing a large number of laminates and packaging. [Solution] A laminate comprising a base layer 11 containing polyethylene terephthalate and a thermoplastic sealant layer 13, wherein the base layer 11 has a first surface 10F which is the outermost surface of the laminate, and the laminate has a weak portion 15 which extends linearly when viewed from a position opposite the first surface 10F, and the weak portion 15 includes a laser processing mark 16 which is cut from the first surface 10F toward the interior of the laminate, and the polyethylene terephthalate contains polyethylene terephthalate in which dicarboxylic acid units in the repeating units contain terephthalic acid and isophthalic acid.

Description

Technical Field

[0005] ,

[0001] The present invention relates to a laminate used for a package, a package, a method for manufacturing the laminate, and a method for manufacturing the package.

Background Art

[0002] Packages widely used for containing various objects such as daily necessities, cosmetics, and pharmaceuticals are manufactured from a laminate including a resin base material layer and a thermoplastic sealant layer. The sealant layer in the package is fused at the periphery of the package. An opening induction line for inducing tearing of the package includes a vulnerable part which is a part imparted with vulnerability. Laser processing for making a cut in a part in the thickness direction of the laminate from the surface of the base material layer toward the inside of the laminate is used for forming the vulnerable part (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, a difference in the depth of the cut occurring during the production of a large number of packages will cause a large difference in the ease of inducing tearing and the force required for tearing between the packages. On the other hand, suppressing the depth of the cut within a certain range will newly impose an excessive production load such as forcing a very high set value on the laser output itself or forcing a very narrow margin on the laser output error.

Means for Solving the Problems

[0006] A packaging body for solving the above problems is a packaging body composed of laminates, having a peripheral portion where the sealant layers are fused together, and the fragile portion is located at the intended opening position of the packaging body.

[0007] A method for manufacturing a laminate to solve the above problems is a method for manufacturing a laminate comprising forming a weak portion in a film by irradiating a laser onto a film in which a substrate layer containing polyethylene terephthalate and a thermoplastic sealant layer are laminated, wherein the polyethylene terephthalate contains polyethylene terephthalate in which terephthalic acid and isophthalic acid are contained in the dicarboxylic acid units in the repeating units, and the laser is irradiated onto the film facing the substrate layer.

[0008] A method for manufacturing a packaging body to solve the above problems is a method for manufacturing a packaging body which includes forming a weak portion in a film by irradiating a laser onto a film in which a base layer containing polyethylene terephthalate and a thermoplastic sealant layer are laminated, and fusing the sealant layers together, wherein the polyethylene terephthalate contains polyethylene terephthalate in which terephthalic acid and isophthalic acid are contained in the dicarboxylic acid units in the repeating units, and the laser is irradiated onto the film facing the base layer.

[0009] The above configurations make it possible to mitigate variations in the depth of laser-processed marks due to fluctuations in laser output. This prevents the need to set excessively high laser output values ​​or impose insufficient margins on laser output errors in order to suppress variations in the depth of laser-processed marks. Furthermore, it helps to reduce variations in the depth of laser-processed marks when manufacturing a large number of laminates or packaging materials.

[0010] The laminate further comprises an intermediate layer sandwiched between the substrate layer and the sealant layer, and the laser processing marks may have ends in the thickness direction of the laminate within the intermediate layer. According to the above laminate, it is possible to improve the reproducibility of preventing the edges of laser-processed marks from reaching the sealant layer and keeping them within the intermediate layer. Therefore, when manufacturing a large number of laminates and packaging bodies, variations in the depth of laser-processed marks can be suppressed, and it is also possible to expand the margin of error for processing required for sealing the packaging body and stabilize the sealing performance of the packaging body.

[0011] In the laminate described above, the proportion of isophthalic acid in the total dicarboxylic acid units of polyethylene terephthalate contained in the base layer may be 0.5 mol% or more and 5 mol% or less. The above-described laminate also makes it possible to enhance the effectiveness of mitigating variations in the depth of laser-processed marks in response to fluctuations in laser output.

[0012] In the laminate described above, the intrinsic viscosity of the polyethylene terephthalate contained in the base layer may be 0.58 dl / g or more and 0.80 dl / g or less. According to the above laminate, since the intrinsic viscosity of polyethylene terephthalate contained in the base layer is 0.58 dl / g or higher, it is possible to provide the base layer with the durability and weather resistance required for packaging. Furthermore, since the intrinsic viscosity of polyethylene terephthalate contained in the base layer is 0.80 dl / g or lower, it is possible to reduce the process load caused by handling raw materials in the manufacturing process of the base layer, such as extrusion, casting, and roll stretching.

[0013] In the laminate described above, the width of the laser processing marks may extend from the sealant layer toward the outermost surface. According to the above laminate, the width of the laser processing marks widens towards the outermost surface, making it easy to irradiate the laser in the direction from the outermost surface toward the sealant layer. Furthermore, it becomes easier to identify the presence of weak areas from a position opposite the outermost surface, thus facilitating handling of weak areas by users of the laminate or packaging. [Effects of the Invention]

[0014] According to the present invention, it is possible to suppress variations in the depth of laser processing marks when manufacturing a large number of laminates or packaging materials. [Brief explanation of the drawing]

[0015] [Figure 1] A partial cross-sectional view showing a portion of the cross-sectional structure in one embodiment of a laminate. [Figure 2] A partial cross-sectional view showing an enlarged cross-sectional structure of a laminate in one embodiment. [Figure 3] A plan view showing the planar structure of one embodiment of the packaging. [Figure 4] A process diagram showing the irradiation process in one embodiment of the manufacturing direction of a laminate. [Figure 5] A graph showing the relationship between laser output and laser processing depth in the example. [Figure 6] A graph showing the relationship between laser output and the fracture strength of the laminate in the example. [Figure 7] A graph showing the relationship between laser output and the width of the laser-processed area in the example. [Figure 8] A graph showing the relationship between the depth of laser processing marks and the fracture strength in the examples. [Figure 9] A graph showing the relationship between the width of the laser-processed mark and the fracture strength in the example. [Figure 10] An optical microscope image showing a magnified cross-sectional structure of the laminate in the example.

Mode for Carrying Out the Invention

[0016] Hereinafter, an embodiment of a laminate, a package, a method for manufacturing a laminate, and a method for manufacturing a package will be described. [Laminate] As shown in FIG. 1, the laminate 10 includes a base material layer 11 and a sealant layer 13. The laminate 10 has a first surface 10F that is the first outermost surface and a second surface 10R that is the second outermost surface located on the side opposite to the first surface. The first surface 10F is the surface of the base material layer 11, and the second surface 10R is the surface of the sealant layer. The laminate 10 may include an intermediate layer 12. The intermediate layer 12 is sandwiched between the base material layer 11 and the sealant layer 13. Note that FIG. 1 shows an example in which the laminate 10 includes the intermediate layer 12.

[0017] The laminate 10 includes a fragile portion 15 that is a portion subjected to half-cut processing. The half-cut processing is to irradiate the laminate 10 with a laser and thereby cut a part of the laminate 10 in the thickness direction. The fragile portion 15 is a portion where the laser processing marks are located in the laminate 10. The laser processing marks extend linearly when viewed from a position facing the first surface 10F of the laminate 10. The shape of the laser processing marks may be linear or curved. The shape of the laser processing marks may be a continuous line or a broken line. The number of the laser processing marks may be one or two or more adjacent to each other.

[0018] The opening of the fragile portion 15 may be located on the first surface 10F or the second surface 10R. From the viewpoint of suppressing the reduction in the sealing property by the sealant layer 13, the opening of the fragile portion 15 is preferably located on the first surface 10F. The laser irradiated to the laminate 10 may be irradiated in a direction from the base material layer 11 toward the sealant layer 13 or in a direction from the sealant layer 13 toward the base material layer 11. Note that FIG. 1 shows an example in which the laser is irradiated in a direction from the base material layer 11 toward the sealant layer 13, and an example in which the laminate 10 includes laser processing marks that open to the first surface 10F.

[0019] [Base material layer 11] The base layer 11 possesses physical properties such as durability and impact resistance required for the outermost layer of a product formed from the laminate 10. The base layer 11 may consist of a single layer or a laminate of multiple layers.

[0020] The material constituting the base layer 11 includes recycled polyethylene terephthalate (PET). The PET products subject to recycling include used PET bottles. The recycled PET constituting the base layer 11 is at least one of PET recycled by mechanical recycling and PET recycled by chemical recycling.

[0021] Mechanical recycling involves crushing and washing PET products to remove surface dirt and foreign matter, and then exposing the resin to high temperatures to remove contaminants remaining inside the resin. Chemical recycling involves crushing and washing PET products to remove surface dirt and foreign matter, then depolymerizing the resin back to intermediate raw materials, and finally repurifying and repolymerizing these intermediate raw materials to produce PET. From the perspective of reducing the manufacturing cost and environmental impact of the base layer 11, it is preferable that the recycled PET contained in the base layer 11 is PET recycled by mechanical recycling. Compared to chemical recycling, mechanical recycling does not require large-scale equipment for chemical reactions, so the cost and environmental impact of producing recycled PET are lower.

[0022] The materials constituting the base layer 11 may include virgin PET, which is newly synthesized PET from raw materials such as petroleum, in addition to recycled PET, or polyester other than recycled PET. Preferably, the mass ratio of recycled PET constituting the base layer 11 is 60% or more and 100% or less of the total mass of the base layer 11.

[0023] The repeating units of PET include diol units and dicarboxylic acid units. The dicarboxylic acid units of recycled PET include terephthalic acid and isophthalic acid. The dicarboxylic acid units of the PET constituting the base layer 11 also include terephthalic acid and isophthalic acid. Preferably, the proportion of isophthalic acid in the total dicarboxylic acid units of the PET constituting the base layer 11 is 0.5 mol% or more and 5 mol% or less. If the proportion of isophthalic acid in the total dicarboxylic acid units is 0.5 mol% or more, it becomes easier to obtain the effect of softening the base layer 11 and suppressing laser propagation. If the proportion of isophthalic acid in the total dicarboxylic acid units is 5 mol% or less, it becomes easier to ensure that the base layer 11 has enough hardness to maintain the shape of the laminate 10.

[0024] When the PET used to make up the resin film for packaging purposes is virgin PET, the diol unit is ethylene glycol and the dicarboxylic acid unit is terephthalic acid. In contrast, the dicarboxylic acid used as a raw material for PET bottles contains isophthalic acid in addition to terephthalic acid to improve the processability of the resin during bottle molding. The dicarboxylic acid unit of the PET that makes up PET bottles also contains both terephthalic acid and isophthalic acid. Isophthalic acid shortens the main chain of PET compared to PET made only of terephthalic acid, suppresses crystallization of PET, and improves the processability of PET. The diol unit of the PET that makes up PET bottles may contain diethylene glycol in addition to ethylene glycol, or it may contain only ethylene glycol.

[0025] The average molecular weight of the PET constituting the base layer 11 is not particularly limited, but is preferably, for example, 1,000 to 1,000,000. The material constituting the base layer 11 may also include resins other than PET, as well as various additives such as plasticizers.

[0026] The intrinsic viscosity of the PET constituting the base layer 11 is preferably 0.58 dl / g or more and 0.8 dl / g or less. If the intrinsic viscosity of the polyethylene terephthalate contained in the base layer 11 is 0.58 dl / g or more, it is possible to obtain the durability and weather resistance required for packaging in the base layer 11. Furthermore, since the intrinsic viscosity of the polyethylene terephthalate contained in the base layer 11 is 0.80 dl / g or less, it is possible to reduce the process load caused by the handling of raw materials in the manufacturing process of the base layer 11, such as extrusion, casting, and roll stretching.

[0027] The materials constituting the base layer 11 may include polyesters other than recycled PET and virgin PET. Polyesters other than recycled PET and virgin PET may have carboxylic acid units such as linear aliphatic carboxylic acids or cyclic aliphatic carboxylic acids. The materials constituting the base layer 11 may also include additives other than polyester. Examples of additives include color inhibitors, antistatic agents, weather inhibitors, UV absorbers, deodorants, and antioxidants.

[0028] The first surface 10F of the base material layer 11 may have an anchor coat layer made of an anchor coat agent, or a printed layer of characters, figures, symbols, patterns, etc. formed by printing. The surface of the base material layer 11 opposite to the first surface 10F may also have a printed layer, or it may be surface-treated to improve adhesion with other adjacent layers. The surface of the base material layer 11 may also have

[0029] The thickness of the base layer 11 is preferably 3 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less. If the thickness of the base layer 11 is 3 μm or more, it is possible to obtain durability and impact resistance of the base layer 11. Furthermore, if the thickness of the base layer 11 is 50 μm or less, it is possible to improve the processability of the laminate 10 comprising the base layer 11.

[0030] The base layer 11 can be formed using known film forming methods such as extrusion molding. Cooling in extrusion molding can also be done using known methods such as cooling rolls, air cooling, or water cooling. The base layer 11 may be a stretched film or an unstretched film. The base layer 11 can be stretched using known methods such as uniaxial stretching or biaxial stretching.

[0031] [Sealant layer 13] The sealant layer 13 is a layer that enables thermal fusion between a part of the sealant layer 13 and other parts of it. The sealant layer 13 may consist of a single layer or a laminate of multiple layers. If the sealant layer 13 comprises multiple layers, the composition of each layer constituting the sealant layer 13 may be the same as that of the other layers, or the constituent layers of the sealant layer 13 may include layers with different compositions.

[0032] The material constituting the sealant layer 13 may be a linear polyolefin or a cyclic polyolefin. Examples of linear polyolefins include esterified ethylene resins, propylene resins, ethylene-propylene copolymers, and ethylene-α,β unsaturated carboxylic acid copolymers. Examples of cyclic polyolefins include ring-opening metathesis polymers (COPs) or cyclic olefin copolymers (COCs). The material constituting the sealant layer 13 may also contain additives such as light-shielding agents.

[0033] The thickness of the sealant layer 13 is preferably 20 μm or more and 100 μm or less, and more preferably 30 μm or more and 70 μm or less. If the thickness of the sealant layer 13 is 20 μm or more, sufficient sealing performance can be obtained by the sealant layer 13. Furthermore, if the thickness of the sealant layer 13 is 100 μm or less, the processability of the laminate 10 having the sealant layer 13 can be improved.

[0034] [Middle class 12] The intermediate layer 12 may be a barrier layer that suppresses the permeation of oxygen and water vapor, or a reinforcing layer that enhances the impact resistance and mechanical toughness of the laminate 10. The intermediate layer 12 may also be a light-shielding layer that blocks light transmission, or a printed layer with printing applied to it. Note that variations in the depth of laser processing marks can occur in the laminate 10 with an intermediate layer 12, whether the intermediate layer 12 can absorb the laser or reflect a portion of the laser, for example, when the base layer 11 is not penetrated by the laser processing or when the processing is stopped inside the intermediate layer 12. Among these, variations in the depth of laser processing marks are particularly pronounced in configurations with an intermediate layer 12 that can absorb the laser; therefore, suppressing variations by including the base layer 11 as described above is particularly effective in the laminate 10 with an intermediate layer 12 that can absorb the laser.

[0035] The barrier layer may be a metal foil such as aluminum foil. The barrier layer may be a vapor-deposited film of a metal such as aluminum, tin, chromium, or nickel, or a vapor-deposited film of an inorganic oxide such as silicon dioxide, aluminum oxide, titanium dioxide, or zirconium oxide. The barrier layer may also be a resin film made of an ethylene-vinyl acetate copolymer saponified product or the like.

[0036] The reinforcing layer may be a nylon film such as 6-nylon, 6,6-nylon, 11-nylon, or 12-nylon, or a copolymer nylon film which is a copolymer of 6-nylon and 6,6-nylon. The light-shielding layer is, for example, a resin layer containing a light-shielding pigment. Examples of light-shielding pigments include carbon black, graphite, aniline black, titanium dioxide, barium oxide, aluminum hydroxide, and zinc oxide.

[0037] Methods for laminating the base layer 11 and the intermediate layer 12, laminating the intermediate layer 12 and the sealant layer 13, or laminating the base layer 11 and the sealant layer 13 while omitting the intermediate layer 12, can be known methods. The method for laminating each layer can be, for example, a dry lamination method, an extrusion lamination method, or a sandwich lamination method utilizing the extrusion lamination method. The adhesive used in the dry lamination method can be a known laminating adhesive. The laminating adhesive is selected from the group consisting of, for example, polyurethane-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate-based, and cellulose-based adhesives.

[0038] [Vulnerable part 15] Referring to Figure 2, the structure of the weak area 15 will be explained. The laser-cut marks 16 that constitute the weak area 15 are notches extending from the first surface 10F into the interior of the laminate 10. The bottom of the groove of the laser-cut mark 16 is the end 16E, which is located on the side of the second surface 10R, of the two ends that the laser-cut mark 16 has in the thickness direction of the laminate 10. The opening of the laser-cut mark 16 is located on the opposite side of the end 16E, of the two ends that the laser-cut mark 16 has in the thickness direction of the laminate 10.

[0039] The end portion 16E of the laser-cut mark 16 may be located inside the base layer 11, inside the sealant layer 13, or inside the intermediate layer 12. The end portion 16E of the laser-cut mark 16 may be located within the same layer in the direction in which the laser-cut mark 16 extends, or may be located in different layers. From the viewpoint of improving the sealing performance of the sealant layer 13, it is preferable that the end portion 16E of the laser-cut mark 16 be located inside the base layer 11 or inside the intermediate layer 12. From the viewpoint of improving the ease of opening using the vulnerable portion 15, it is preferable that the end portion 16E of the laser-cut mark 16 be located inside the intermediate layer 12.

[0040] The strength of the weak point 15 is preferably high enough to prevent it from breaking due to vibration or other factors before the package is opened, and low enough to allow it to easily break due to external forces such as the force of the user's hand when the package is opened. From the viewpoint of easily obtaining toughness that satisfies these conditions, it is preferable that the laminate 10 has an intermediate layer 12 and that the end portion 16E is located within the intermediate layer 12. Furthermore, it is preferable that the end portion 16E is located within the same intermediate layer 12 in the direction in which the laser processing mark 16 extends, across the entire laser processing mark 16. Figure 2 shows an example in which the end portion 16E of the laser processing mark 16 is located within the intermediate layer 12.

[0041] The vulnerable portion 15 may have raised portions 17 at each end of the laser-processed mark 16 in the width direction, extending in the direction of the laser-processed mark 16. The raised portions 17 are parts that locally rise at the edges of the openings at both ends of the laser-processed mark 16 in the width direction. If the opening of the laser-processed mark 16 is located on the first surface 10F, the raised portions 17 are also located on the first surface 10F. When the laser-processed mark 16 is formed by laser irradiation, the substrate layer 11 melts due to heat generated by the absorption of laser light by the substrate layer 11. A portion of the melted substrate layer 11 moves to the side of the laser-processed mark 16, and as a result, the raised portions 17 are formed. The presence of raised portions 17 in the laser-processed mark 16 helps to visually and tactilely perceive the presence of the vulnerable portion 15.

[0042] The length of the laser-processed marks 16 in the width direction gradually increases from the sealant layer 13 toward the substrate layer 11. The maximum width W of the laser-processed marks 16 is the length in the width direction of the gap between the two raised portions 17. The degree to which the length of the laser-processed marks 16 in the width direction increases per unit thickness may increase, remain constant, or decrease from the sealant layer 13 toward the substrate layer 11. Figure 2 shows an example in which the length of the laser-processed marks 16 in the width direction increases per unit thickness from the sealant layer 13 toward the substrate layer 11.

[0043] The depth of the laser-processed mark 16 is the difference between the thickness T of the laminate 10 and the length X along the thickness direction from the end 16E to the second surface 10R. The thickness T of the laminate 10 is the total thickness of the laminate 10 in the portion where the weak portion 15 is not formed. From the viewpoint of improving the sealing performance of the product formed using the laminate 10, it is preferable that the depth of the laser-processed mark 16 does not reach the sealant layer 13. Furthermore, if the laminate 10 includes a barrier layer as an intermediate layer 12, it is preferable that the depth of the laser-processed mark 16 does not reach the barrier layer in order to suppress a decrease in the barrier performance of the laminate 10.

[0044] As described above, differences in the depth of laser-processed marks 16 during the manufacturing of numerous laminates 10 and packaging materials result in significant variations in the ease of tearing and the force required for tearing between products. On the other hand, limiting the depth of laser-processed marks 16 to a certain range imposes an excessive manufacturing burden by requiring very high settings for the laser output itself or imposing a very narrow margin of error for the laser output.

[0045] If the base layer 11 comprises multiple layers, the composition of each layer constituting the base layer 11 may be the same as that of the other layers, or the constituent layers of the base layer 11 may include layers with different compositions. The layers constituting the base layer 11 may include a layer made of recycled PET and a layer made of virgin PET. The layers constituting the base layer 11 may include multiple layers containing recycled PET in different proportions. The depth of the laser processing marks 16 has small variations in the layers made of recycled PET and large variations in the layers made of virgin PET. From the viewpoint of suppressing variations in the depth of the laser processing marks 16, it is preferable that the layers made of recycled PET are closer to the opening of the laser processing marks 16 than the layers made of virgin PET.

[0046] When the base layer 11 includes an intermediate layer 12, the absorption rate of the laser irradiated onto the laminate 10 may be higher in the base layer 11 than in the intermediate layer 12, or higher in the intermediate layer 12 than in the base layer 11. When irradiating the laser from the base layer 11 toward the sealant layer 13, it is preferable that the absorption rate of the base layer 11 be higher than that of the intermediate layer 12, from the viewpoint of suppressing variations in the depth of the laser processing marks 16.

[0047] Processing is preferable in order from the layer with the highest laser absorption rate, as the processing speed slows down as the laser irradiation progresses, thus suppressing variations in the depth at the end of processing.

[0048] [Package 20] The packaging is manufactured using the laminates described above. Examples of packaging include side-seal packaging, two-side-seal packaging, three-side-seal packaging, four-side-seal packaging, envelope-type packaging, pillow-seal packaging, pleated-seal packaging, flat-bottom-seal packaging, and square-bottom-seal packaging. Other examples of packaging include one-piece packaging, two-piece packaging, and packaging with other spouts or zippers for opening and closing. Further examples of packaging include self-standing packaging, tube containers, and liquid-filled paper containers containing a paper substrate layer.

[0049] Examples of contents that can be contained in a package include various food and beverage products such as fruit juice, water, alcohol, prepared foods, processed seafood products, frozen foods, meat products, simmered dishes, mochi (rice cakes), liquid soups, condiments such as soy sauce and sauces, and fresh confectionery, as well as non-food items such as liquid detergents, cosmetics, and chemical products.

[0050] Referring to Figure 3, an example of a packaging body, a three-side seal type packaging body, will be described. The packaging body 20 is a bag shape formed from a laminate 10 and is configured to be sealable. In the packaging body 20, the base material layer 11 is located outside the sealant layer 13. The ends of the sealant layer 13 are joined together on three sides of the packaging body 20. The portion where the ends of the sealant layer 13 are joined together is the sealing portion 21 of the packaging body 20.

[0051] The sealing portion 21 includes an opening start portion 22. The opening start portion 22 is a notch extending inward from a portion of the periphery of the sealing portion 21. The packaging body 20 includes an opening guide line 23 extending in one direction from the opening start portion 22. The opening guide line 23 connects two opposing sides within the sealing portion 21, which is one of the three sides of the packaging body 20. The opening start portion 22 is one end of the opening guide line 23.

[0052] The opening guide line 23 is a portion of the packaging 20 that provides partial vulnerability. The opening guide line 23 is a vulnerable portion 15 formed in the laminate 10. The opening guide line 23 may be formed before the sealing portion 21 is formed, or it may be formed after the sealing portion 21 is formed. When opening the packaging 20, the tear in the laminate 10 starting from the opening start portion 22 progresses along the opening guide line 23 and does not deviate from the opening guide line 23.

[0053] [Manufacturing method] The method for manufacturing the laminate includes (A) laminating a sealant layer 13 onto a base layer 11, and (B) irradiating the laminate 10 with a laser to form laser processing marks 16. The method for manufacturing the packaging includes (A) laminating a sealant layer 13 onto a base layer 11, (B) irradiating the laminate 10 with a laser to form laser processing marks 16, and (C) heat-sealing the sealant layers 13 together.

[0054] (A) Laminating a sealant layer 13 onto a base layer 11 includes, if the laminate 10 includes an intermediate layer 12, laminating the intermediate layer 12 onto the base layer 11 and then laminating the sealant layer 13 onto the intermediate layer 12. Alternatively, (A) Laminating a sealant layer 13 onto a base layer 11 includes laminating the sealant layer 13 onto the intermediate layer 12 and then laminating the intermediate layer 12 and the base layer 11.

[0055] The lamination method for the base layer 11 and the sealant layer 13, the lamination method for the base layer 11 and the intermediate layer 12, and the lamination method for the intermediate layer 12 and the sealant layer 13 may be dry lamination, extrusion lamination, casting, or T-die.

[0056] Furthermore, if the first surface 10F is an anchor coat layer, the anchor coat layer may be laminated onto the base layer 11 before laminating the base layer 11 and the sealant layer 13, or the anchor coat layer may be laminated onto the base layer 11 after laminating the base layer 11 and the sealant layer 13.

[0057] Furthermore, if the first surface 10F includes a printed layer, the printed layer may be laminated on the first surface 10F before lamination of the base material layer 11 and the sealant layer 13, or the printed layer may be laminated on the first surface 10F after lamination of the base material layer 11 and the sealant layer 13.

[0058] Furthermore, if the printing layer is provided on the surface of the base layer 11 opposite to the first surface 10F, the printing layer is formed on the base layer 11 before lamination of the base layer 11 and the sealant layer 13, or before lamination of the base layer 11 and the intermediate layer 12.

[0059] (C) Heat sealing the sealant layers 13 together forms a sealing portion 21. Examples of heat seal types for forming the sealing portion 21 include side seal type, two-way seal type, three-way seal type, four-way seal type, envelope seal type, pillow seal type, pleated seal type, flat-bottom seal type, and square-bottom seal type. Examples of methods for forming the sealing portion 21 include bar seal, rotary roll seal, belt seal, impulse seal, high-frequency seal, and ultrasonic seal.

[0060] One example of forming the sealing portion 21 is to use a single rectangular laminate 10. The laminate 10 is folded in half so that the sealant layers 13 of the single laminate 10 are in contact with each other. Next, the sealant layers 13 on three sides of the folded laminate 10 are heat-fused together to produce a three-sided sealed packaging 20.

[0061] Another example of forming the sealing portion 21 involves using two rectangular laminates 10. The two laminates 10 are stacked so that the sealant layers 13 located on all four sides of the two laminates 10 are in contact with each other. The sealant layers 13 located on all four sides are heat-fused together to produce a four-sided sealed package 20.

[0062] Another example of forming the sealing portion 21 uses a single rectangular laminate 10. The laminate 10 is bent into a cylindrical shape so that the sealant layer 13 of the single laminate 10 faces inward. The sealant layers 13 located at the connection points of the cylindrical surface are heat-fused together to form a back-bonded portion, which is an example of the sealing portion 21. The sealant layers 13 located at the upper and lower openings of the cylindrical surface are also heat-fused together to produce the remainder of the sealing portion 21.

[0063] (B) Irradiating the laminate 10 with a laser to form laser processing marks 16 is equivalent to forming a weak area 15 or forming an opening guide line 23. As shown in Figure 4, the laser may be irradiated by the laser head 50 from the substrate layer 11 toward the sealant layer 13, or from the sealant layer 13 toward the substrate layer 11. The laser absorbed by the substrate layer 11 melts a portion of the substrate layer 11, forming a laser-processed mark 16. The substrate layer 11 irradiated with the laser absorbs the laser light and generates heat. The portion of the substrate layer 11 that has melted due to the heat forms a cut and, along with the edge of the laser spot, forms a raised portion 17.

[0064] The wavelength range of the laser is included in the wavelength range absorbed by the substrate layer 11. The wavelength range absorbed by the substrate layer 11 may be the infrared wavelength range or the near-infrared wavelength range. From the viewpoint of being more easily absorbed by PET compared to nylon resins and polypropylene resins, the wavelength range of the laser is preferably 700 nm to 2000 nm, and more preferably 900 nm to 1100 nm. The laser head 50 may be a continuous-oscillation type carbon dioxide laser head or a pulsed-oscillation type carbon dioxide laser head. Alternatively, the laser head 50 may be a continuous-oscillation type YAG laser head or a pulsed-oscillation type YAG laser head.

[0065] The spot diameter of the laser emitted by the laser head 50 and the average output of the laser head 50 are set appropriately according to the required depth and width of the laser-processed mark 16. The laser spot diameter is the Gaussian beam diameter. The average output of the laser head 50 is set by the output percentage within the laser output conditions. For example, if the laser head 50 has a maximum output of 30W and is set to 50% output, the average output of the laser head 50 will be 15W.

[0066] The laser spot diameter is, for example, 1 μm to 500 μm, preferably 2 μm to 100 μm. The average output of the laser head 50 is, for example, 5 W to 50 W, preferably 10 W to 30 W.

[0067] From the viewpoint of suppressing variations in the depth of the laser-processed marks 16, it is preferable that the scanning speed of the laser head 50 remains constant throughout the period during which the laser-processed marks 16 are formed. The scanning of the laser head 50 may be performed by scanning the laser head 50 with respect to the laminate 10, or by scanning the laminate 10 with respect to the laser head 50, or a combination of these. By slowing down the scanning speed of the laser head 50, the depth of the laser-processed marks 16 can be increased. Conversely, by increasing the scanning speed of the laser head 50, the depth of the laser-processed marks 16 can be made shallower. The scanning speed of the laser head 50 is, for example, 200 m / min or less, and preferably 100 m / min.

[0068] Forming the laser-processed marks 16 may include taking out a portion of the laminate 10 and inspecting the appearance of the laser-processed marks 16 using various optical inspection devices in order to inspect the shape of the laser-processed marks 16. Alternatively, forming the laser-processed marks 16 may include taking out a portion of the laminate 10 and inspecting the tensile breaking strength of the laminate 10 in order to inspect the properties of the laser-processed marks 16.

[0069] [Example 1] The laminate 10 of Example 1 was prepared by dry lamination using the following films as the base layer 11, intermediate layer 12, and sealant layer 13. The proportion of isophthalic acid to the total dicarboxylic acid units of PET contained in the base layer 11 of Example 1 is 0.5 mol% or more and 5 mol% or less. In addition, the intrinsic viscosity of the PET contained in the base layer 11 of Example 1 is 0.58 dl / g or more and 0.80 dl / g or less.

[0070] Hereafter, PET film will also be referred to as "PET," nylon film as "Ny," unoriented polypropylene film as "CPP," and biaxially oriented polypropylene film as "OPP." A two-component aliphatic ester-based dry lamination adhesive (main component product name: Takelac® A-626 / curing agent product name: Takenate® A-50, manufactured by Mitsui Chemicals, Inc.) was used to bond each layer.

[0071] • Substrate layer 11: Recycled PET (thickness 12 μm / product name: R8100, manufactured by Toyobo Co., Ltd.) • Interlayer 12: Ny (thickness 15 μm / product name: Bonyl (registered trademark)-W, manufactured by Kojin Film & Chemicals Co., Ltd.) • Sealant layer 13: CPP (thickness 50 μm / product name: FHK2, manufactured by Futamura Chemical Co., Ltd.)

[0072] [Comparative Example 1] A laminate 10 of Comparative Example 1 was prepared using the following films as the base layer 11, intermediate layer 12, and sealant layer 13. The same aliphatic ester-based dry lamination adhesive as in Example 1 was used to bond each layer. • Substrate layer 11: Virgin PET (thickness 12 μm / product name: E5100, manufactured by Toyobo Co., Ltd.) • Interlayer 12: Ny (thickness 15 μm / product name: Bonyl (registered trademark)-W, manufactured by Kojin Film & Chemicals Co., Ltd.) • Sealant layer 13: CPP (thickness 50 μm / product name: FHK2, manufactured by Futamura Chemical Co., Ltd.)

[0073] [Comparative Example 2] A laminate 10 of Comparative Example 2 was prepared using the following films as the base layer 11, intermediate layer 12, and sealant layer 13. The same aliphatic ester-based dry lamination adhesive as in Example 1 was used to bond each layer. • Substrate layer 11: OPP (thickness 20 μm / product name: FOR, manufactured by Futamura Chemical Co., Ltd.) • Interlayer 12: Ny (thickness 15 μm / product name: Bonyl (registered trademark)-W, manufactured by Kojin Film & Chemicals Co., Ltd.) • Sealant layer 13: CPP (thickness 50 μm / product name: FHK2, manufactured by Futamura Chemical Co., Ltd.)

[0074] [Comparative Example 3] A laminate 10 of Comparative Example 3 was prepared using the following films as the base layer 11, intermediate layer 12, and sealant layer 13. The same aliphatic ester-based dry lamination adhesive as in Example 1 was used to bond each layer. • Substrate layer 11: Ny (thickness 15 μm / Product name: Emblem (registered trademark) ON, manufactured by Unitika Ltd.) • Interlayer 12: Ny (thickness 15 μm / product name: Bonyl (registered trademark)-W, manufactured by Kojin Film & Chemicals Co., Ltd.) • Sealant layer 13: CPP (thickness 50 μm / product name: FHK2, manufactured by Futamura Chemical Co., Ltd.)

[0075] [evaluation] Laser processing was performed on the laminates 10 of Example 1 and each comparative example using the following output conditions. In this process, the laminate 10 was wrapped around a roll, and the laser was irradiated onto the outermost surface of the rotating roll-shaped raw material, thereby scanning the laser along the MD direction of the base layer 11 and the intermediate layer 12. Six mutually different locations were set as the laser irradiation positions in the axial direction of the roll. That is, six weak points 15 were formed on the raw material of Example 1 and each comparative example. The laser processing marks 16 were then observed using a scanning electron microscope, and the width and depth of the laser processing marks 16 were measured. The average values ​​of the six weak points 15 in Example 1 and each comparative example were taken as the width and depth of the laser processing marks 16 in that example. [Output conditions] • Head: CO2 laser head (Product name: ML-Z9510, manufactured by Keyence Corporation) ·Wavelength range: 10.6μm • Average laser power output: 10W to 35W • Scanning speed: 80 m / min • Spot diameter: 2μm

[0076] Furthermore, for the laminates 10 of Examples 1 to Comparative Example 3 after laser processing, the tensile fracture stress in the TD direction of the weak points 15 was measured using a tensile testing machine, and the average value of the six weak points 15 in each example was taken as the fracture strength for that example. The tensile fracture stress was measured using a method in accordance with JIS K7127:1999 (ISO 527-3:1995) "Plastics - Test methods for tensile properties - Part 3: Test conditions for films and sheets" and JIS K7161-1:2014 (ISO 527-1:2012) "Plastics - Methods for determining tensile properties - Part 1: General rules", with the following conditions. [Measurement conditions] ·Distance between gauge lines: 50mm • Test speed: 100 mm / min

[0077] Figure 5 shows the relationship between the average power output and the depth of the laser-processed marks 16 in Example 1, along with the results of Comparative Examples 1 to 3. Figure 6 shows the relationship between the average power output and the breaking strength in Example 1, along with the results of Comparative Examples 1 to 3. Figure 7 shows the relationship between the average power output and the width of the laser-processed marks 16 in Example 1, along with the results of Comparative Examples 1 to 3. Figure 8 shows the relationship between the depth of the laser-processed marks 16 and the breaking strength in Example 1, along with the results of Comparative Examples 1 to 3. Figure 9 shows the relationship between the width of the laser-processed marks 16 and the breaking strength in Example 1, along with the results of Comparative Examples 1 to 3. Figure 10 is an optical microscope image showing the cross-sectional structure of the laminate in Example 1, which corresponds to the structure in Figure 2.

[0078] As shown in Figure 5, the depth of the laser-processed marks 16 in the laminate 10 of Example 1 was between 21 μm and 18 μm, with a difference of only about 3 μm. Furthermore, at an average power of 20 W, it was observed that the laser-processed marks 16 reached the intermediate layer 12. It was also observed that the depth of the laser-processed marks 16 decreased slightly as the average laser power increased from 20 W to 32 W, but the decrease was almost negligible, indicating that the depth remained approximately constant with respect to changes in average power.

[0079] In contrast, the depth of the laser-processed marks 16 in the laminate 10 of Comparative Example 1 was between 14 μm and 24 μm, showing a difference of approximately 10 μm. Furthermore, in Comparative Example 1, at an average output of 20 W, the laser-processed marks 16 reached the intermediate layer 12. It was also observed that the depth of the laser-processed marks 16 increased as the average laser output increased from 20 W to 32 W.

[0080] Furthermore, the depth of the laser processing marks 16 in the laminate 10 of Comparative Example 2 was found to be between 0 μm and 24 μm, with a difference of 24 μm or more. In Comparative Example 2, it was found that at an average power output of 10 W, almost no laser processing marks 16 were observed, and even at an average power output of 20 W, the laser processing marks 16 did not reach the intermediate layer 12. It was also found that the depth of the laser processing marks 16 increased as the average laser power output increased from 20 W to 32 W.

[0081] Furthermore, the depth of the laser processing marks 16 in the laminate 10 of Comparative Example 3 was found to be between 1 μm and 29 μm, with a difference of approximately 28 μm. In Comparative Example 3, it was also found that at an average output of 20 W, the laser processing marks 16 did not reach the intermediate layer 12. It was also found that as the average laser output increased from 20 W to 32 W, the depth of the laser processing marks 16 increased.

[0082] This confirmed that, with the configurations of Example 1 and Comparative Example 1, it is possible to form laser-processed marks 16 in a low power range that does not require excessive laser power. Furthermore, with the configuration of Example 1, it was found that the variation in the depth of the laser-processed marks 16 due to fluctuations in the average laser power was sufficiently mitigated compared to the configurations of Comparative Examples 1 to 3.

[0083] As shown in Figure 6, the fracture strength of the laminate 10 in Example 1 was between 29N and 35N, with a difference of only about 6N. Furthermore, it was observed that the fracture strength decreased slightly as the average laser power increased from 20W to 32W, but the decrease was almost negligible, indicating that the fracture strength remained approximately constant with respect to changes in average power.

[0084] In contrast, the breaking strength of the laminate 10 in Comparative Example 1 was between 20N and 60N, showing a significant difference of approximately 40N. Furthermore, the breaking strength of the laminate 10 in Comparative Example 2 was between 15N and 73N, showing a very large difference of approximately 58N. Similarly, the breaking strength of the laminate 10 in Comparative Example 3 was between 16N and 101N, showing the largest difference of approximately 85N.

[0085] This demonstrated that, with the configuration of Example 1, it is possible to obtain a low breaking strength suitable for opening the package within a low power range that does not require excessive laser output. Furthermore, with the configuration of Example 1, it was found that the fluctuation in breaking strength due to fluctuations in the average laser output was sufficiently mitigated compared to the configurations of Comparative Examples 1 to 3.

[0086] As shown in Figure 7, the width of the laser-processed marks 16 in the laminate 10 of Example 1 was found to be between 55 μm and 102 μm, with a difference of approximately 50 μm. Furthermore, it was observed that the width of the laser-processed marks 16 widened as the average laser power increased from 20 W to 32 W.

[0087] On the other hand, the width of the laser-processed marks 16 in the laminate 10 of Comparative Example 1 was also found to be between 75 μm and 130 μm, with a difference of approximately 55 μm. Furthermore, it was observed that the width of the laser-processed marks 16 widened as the average laser power increased from 20 W to 32 W.

[0088] On the other hand, the width of the laser processing marks 16 in the laminate 10 of Comparative Example 2 was 0 μm or more and 120 μm or less, showing a very large difference of about 120 μm. The width of the laser processing marks 16 in the laminate 10 of Comparative Example 3 was 38 μm or more and 70 μm or less, showing a difference of about 32 μm. As a result, with the configuration of Example 1, a low breaking strength suitable for opening was obtained, the fluctuation in breaking strength due to fluctuations in the average output of the laser was sufficiently mitigated, and the fluctuation in the width of the laser processing marks 16 was found to be about the same as or smaller than that of Comparative Examples 1 and 2.

[0089] As shown in Figure 8, the fracture strength of the laminate 10 in Example 1 decreases as the depth of the laser-processed marks 16 increases. However, the magnitude of the decrease in fracture strength per unit depth was found to be smaller than in any of the comparative examples 1 to 3. This indicates that with the configuration of the laminate 10 in Example 1, fluctuations in the depth of the laser-processed marks 16 due to fluctuations in the average output of the laser are sufficiently mitigated, and even if fluctuations occur, the fluctuation in fracture strength due to the depth fluctuation is also sufficiently small.

[0090] As shown in Figure 9, the fracture strength of the laminate 10 in Example 1 decreases as the width of the laser-processed marks 16 increases. However, the magnitude of the reduction in fracture strength per unit width was found to be smaller than in any of the Comparative Examples 1 to 3. This indicates that, with the configuration of the laminate 10 in Example 1, even if the width of the laser-processed marks 16 changes due to fluctuations in the average laser output, the fluctuation in fracture strength due to the width fluctuation is sufficiently small.

[0091] As shown in Figure 10, it was found that in Example 1, the weak portion 15 was located in the middle of the thickness direction of the intermediate layer 12, with the end 16E of the laser-processed mark 16 being positioned midway. It was also found that the weak portion 15 had raised portions 17 at each end in the width direction of the laser-processed mark 16, which were continuous in the direction of the extension of the laser-processed mark 16.

[0092] According to the above embodiment, the following effects can be obtained. (1) In a range where the average output is sufficiently low, it becomes possible to mitigate variations in the depth of the laser-processed marks 16 in response to fluctuations in the laser output. This prevents the need to set the laser output to an excessively high value or to impose an insufficient margin of error on the laser output in order to suppress variations in the depth of the laser-processed marks 16. In addition, it is possible to suppress variations in the depth of the laser-processed marks 16 when manufacturing a large number of laminates 10 or packaging 20.

[0093] (2) It is possible to improve the reproducibility of preventing the end 16E of the laser processing mark 16 from reaching the sealant layer 13 and keeping it inside the intermediate layer 12. As a result, when manufacturing a large number of laminates 10 and packaging 20, variations in the depth of the laser processing mark 16 can be suppressed, and it is also possible to expand the margin of error for processing required in sealing the packaging 20 and stabilize the sealing performance of the packaging 20.

[0094] (3) When the proportion of isophthalic acid in the total dicarboxylic acid units of PET contained in the base layer 11 is 0.5 mol% or more and 5 mol% or less, it is also possible to enhance the effectiveness of the effects in accordance with (1) above.

[0095] (4) If the intrinsic viscosity of the PET contained in the base layer 11 is 0.58 dl / g or more and 0.80 dl / g or less, it is possible to provide the base layer 11 with the durability and weather resistance required for the packaging 20. Furthermore, if the intrinsic viscosity of the PET contained in the base layer 11 is 0.80 dl / g or less, it is possible to reduce the process load caused by the handling of raw materials in the manufacturing process of the base layer 11, such as extrusion, casting, and roll stretching.

[0096] (5) When the width of the laser processing marks 16 widens from the sealant layer 13 toward the first surface 10F, it is also easy to irradiate the laser in the direction from the first surface 10F toward the sealant layer 13. Furthermore, it becomes easier to identify the presence of the weak area 15 by looking at it from a position opposite the first surface 10F, thus making it easier for users of the laminate 10 or packaging 20 to handle the weak area 15. [Explanation of Symbols]

[0097] 10…Laminate 10F…First page 10R…Second side 11...Base material layer 12…Middle class 13...Sealant layer 15…Vulnerable parts 16…Laser processing marks 16E...End 20...Packaging body

Claims

1. A substrate layer containing recycled polyethylene terephthalate, A laminate comprising a thermoplastic sealant layer, The substrate layer comprises the outermost surface of the laminate, The laminate has a weak portion that extends linearly when viewed from a position opposite the outermost surface, The weak portion includes a laser processing mark that is cut from the outermost surface toward the interior of the laminate, The substrate layer comprises a first layer and a second layer made of polyethylene terephthalate, wherein the proportion of recycled polyethylene terephthalate in the second layer is less than or equal to the proportion of recycled polyethylene terephthalate in the first layer. The first layer is located closer to the outermost surface than the second layer. Laminated structure.

2. A substrate layer containing recycled polyethylene terephthalate, A laminate comprising a thermoplastic sealant layer, The substrate layer comprises the outermost surface of the laminate, The laminate has a weak portion that extends linearly when viewed from a position opposite the outermost surface, The weak portion includes a laser processing mark that is cut from the outermost surface toward the interior of the laminate, The substrate layer comprises a first layer and a second layer, wherein the proportion of recycled polyethylene terephthalate in the second layer is less than or equal to the proportion of recycled polyethylene terephthalate in the first layer. The second layer is located closer to the outermost surface than the first layer. Laminated structure.

3. The proportion of recycled polyethylene terephthalate in the second layer is smaller than the proportion of recycled polyethylene terephthalate in the first layer. The laminate according to claim 1 or 2.

4. The recycled polyethylene terephthalate is mechanical polyethylene terephthalate. The laminate according to any one of claims 1 to 3.

5. The recycled polyethylene terephthalate is chemical polyethylene terephthalate. The laminate according to any one of claims 1 to 3.

6. The recycled polyethylene terephthalate is mechanical polyethylene terephthalate. The second layer is made of virgin polyethylene terephthalate. The laminate according to claim 1.

7. Equipped with a printing layer The laminate according to any one of claims 1 to 6.

8. The sealant layer comprises a cyclic olefin copolymer. The laminate according to any one of claims 1 to 7.

9. The sealant layer contains a light-shielding agent. The laminate according to any one of claims 1 to 8.

10. The barrier layer is further sandwiched between the substrate layer and the sealant layer. The laminate according to any one of claims 1 to 9.

11. The barrier layer includes a vapor-deposited film made of aluminum, aluminum oxide, and silicon oxide, or a resin film containing an ethylene-vinyl acetate copolymer saponified product. The laminate according to claim 10.

12. The system further comprises an intermediate layer sandwiched between the substrate layer and the sealant layer, The laser-processed marks have ends in the thickness direction of the laminate within the intermediate layer. The laminate according to any one of claims 1 to 9.

13. The recycled polyethylene terephthalate contains terephthalic acid and isophthalic acid in the dicarboxylic acid units within the repeating units. The laminate according to any one of claims 1 to 12.

14. The proportion of isophthalic acid in the total dicarboxylic acid units of polyethylene terephthalate contained in the substrate layer is 0.5 mol% or more and 5 mol% or less. The laminate according to claim 13.

15. The intrinsic viscosity of the polyethylene terephthalate contained in the substrate layer is 0.58 dl / g or more and 0.80 dl / g or less. The laminate according to any one of claims 1 to 14.

16. The width of the laser-processed mark extends from the sealant layer toward the outermost surface. The laminate according to any one of claims 1 to 15.

17. A packaging body composed of a laminate according to any one of claims 1 to 16, The sealant layers have a peripheral portion that is fused together, The vulnerable portion is located at the intended opening position in the packaging. packaging.

18. A method for manufacturing a laminate, comprising irradiating a film in which a substrate layer containing recycled polyethylene terephthalate and a thermoplastic sealant layer are laminated with a laser to form a weak portion in the film, The substrate layer has the outermost surface of the film and comprises a first layer and a second layer made of polyethylene terephthalate, wherein the proportion of recycled polyethylene terephthalate in the second layer is less than or equal to the proportion of recycled polyethylene terephthalate in the first layer, and the first layer is located closer to the outermost surface than the second layer. The laser is irradiated onto the film from a position opposite to the substrate layer. A method for manufacturing laminates.

19. A method for manufacturing a laminate, comprising irradiating a film in which a substrate layer containing recycled polyethylene terephthalate and a thermoplastic sealant layer are laminated with a laser to form a weak portion in the film, The substrate layer has the outermost surface of the film and comprises a first layer and a second layer, wherein the proportion of recycled polyethylene terephthalate in the second layer is less than or equal to the proportion of recycled polyethylene terephthalate in the first layer, and the second layer is located closer to the outermost surface than the first layer. The laser is irradiated onto the film from a position opposite to the substrate layer. A method for manufacturing laminates.

20. A method for manufacturing a packaging body, comprising irradiating a film in which a substrate layer containing recycled polyethylene terephthalate and a thermoplastic sealant layer are laminated with a laser to form a weak area in the film, and fusing the sealant layers together, The substrate layer has the outermost surface of the film and comprises a first layer and a second layer made of polyethylene terephthalate, wherein the proportion of recycled polyethylene terephthalate in the second layer is less than or equal to the proportion of recycled polyethylene terephthalate in the first layer, and the first layer is located closer to the outermost surface than the second layer. The laser is irradiated onto the film from a position opposite to the substrate layer. A method for manufacturing packaging.

21. A method for manufacturing a packaging body, comprising irradiating a film in which a substrate layer containing recycled polyethylene terephthalate and a thermoplastic sealant layer are laminated with a laser to form a weak area in the film, and fusing the sealant layers together, The substrate layer has the outermost surface of the film and comprises a first layer and a second layer, wherein the proportion of recycled polyethylene terephthalate in the second layer is less than or equal to the proportion of recycled polyethylene terephthalate in the first layer, and the second layer is located closer to the outermost surface than the first layer. The laser is irradiated onto the film from a position opposite to the substrate layer. A method for manufacturing packaging.

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