Method for manufacturing a laminate for a package

Abstract

To improve airtightness of a laminate containing a resin film.SOLUTION: There is provided a method for producing a laminate for a package which comprises: a step of subjecting a resin film 10 containing a polyethylene terephthalate to surface modification treatment by reactive ion etching; and a step of laminating a gas barrier layer 11 on a surface subjected to surface modification treatment, wherein a laminate 20 contains the resin film 10 and the gas barrier layer 11 laminated on the resin film 10, the resin film 10 contains a terephthalic acid component, an isophthalic acid component and a naphthalene dicarboxylic acid component as a dicarboxylic acid component of a polyester, the molar ratio of the isophthalic acid component to the total mass of the dicarboxylic acid component and a diol component is 2×10-1 mol% or more and 9×10-1 mol% or less and the molar ratio of the naphthalene dicarboxylic acid component is 1×10-2 mol% or more and 6×10-2 mol% or less.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a laminate for a package.

Background Art

[0002] Resin films containing polyethylene terephthalate are widely used for packages for packaging contents such as foods, pharmaceuticals, and cosmetics. Generally, this resin film has a property of slightly permeating gases such as oxygen and hydrogen. Therefore, as a package, a laminate of a resin film and a gas barrier layer including a metal film or a metal oxide film is used (see, for example, Patent Document 1). Further, it is desirable that the resin film itself is made of a material having high gas barrier properties in which the material of the resin film hardly permeates gases.

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, in the distribution process of a product packaged in a package composed of a laminate of a resin film and a gas barrier layer, external forces that cause deformations such as friction and bending are repeatedly applied to the product. When such external forces are repeatedly applied to the package, cracks are formed in the gas barrier layer, and the airtightness of the package is lost. Therefore, it is required that the laminate not only enhances the gas barrier properties but also enhances the resistance to deformation to comprehensively improve the airtightness of the package.

Means for Solving the Problems

[0005] The manufacturing method of the laminate for a package that solves the above problems includes a step of performing a surface modification treatment by plasma treatment on a resin film containing polyethylene terephthalate, and a step of laminating a gas barrier layer on the surface subjected to the surface modification treatment. The resin film contains a terephthalic acid component, an isophthalic acid component, and a naphthalenedicarboxylic acid component as the dicarboxylic acid component of the polyester. The molar ratio of the isophthalic acid component to the total amount of the dicarboxylic acid component and the diol component is 2×10 -1 mol% or more and 9×10 -1 mol% or less, and the molar ratio of the naphthalenedicarboxylic acid component is 1×10 -2 mol% or more and 6×10 -2 mol% or less.

[0006] According to the above method, since the molar ratio of isophthalic acid is within the above range, the flexibility of the resin film is enhanced. By enhancing the flexibility of the resin film, the resin film can easily absorb the load applied to the laminate, so the load applied to the gas barrier layer is reduced, and the flex resistance and the like are enhanced. Also, since the molar ratio of the naphthalenedicarboxylic acid component is within the above range, the surface orientation coefficient of the resin film can be increased. By increasing the surface orientation coefficient, the gas barrier property of the resin film itself can be enhanced, and the adhesion to the gas barrier layer can be enhanced. Therefore, the airtightness of the laminate with the gas barrier layer laminated can be comprehensively enhanced. On the other hand, when the surface orientation coefficient increases, the adhesion between the resin film and the gas barrier layer may decrease. However, since the plasma treatment is performed on the laminated surface of the resin film, the adhesion between the resin film and the gas barrier layer can be enhanced. And by enhancing the adhesion between the resin film and the gas barrier layer, the peeling of the gas barrier layer and the generation of cracks can be suppressed. Therefore, the airtightness of the resin film with the gas barrier layer laminated can be comprehensively enhanced. Regarding the above laminate for a package, the molar ratio of the isophthalic acid component to the total amount of the dicarboxylic acid component and the diol component is 5×10 -1 mol% or more and 9×10 -1 mol%The following, and the molar ratio of the naphthalenedicarboxylic acid component may be 4×10 -2 mol% or more and 6×10 -2 mol% or less. According to the above configuration, the airtightness of the laminate for a package with a gas barrier layer laminated can be further comprehensively improved.

[0007] Regarding the method for manufacturing the laminate for a package, the surface modification treatment may be a reactive ion etching treatment. According to the above method, functional groups capable of enhancing the adhesion to the gas barrier layer can be imparted to the surface of the resin film, and impurities adhering to the surface of the resin film can be removed to increase the surface roughness. Thereby, the adhesion between the resin film and the gas barrier layer can be enhanced.

[0008] Regarding the method for manufacturing the laminate for a package, the step of laminating the gas barrier layer may include a step of laminating a first film containing at least one of aluminum oxide and silicon oxide on the surface subjected to the surface modification treatment.

[0009] According to the above method, a film having transparency can be formed on the resin film. Also, the adhesion between the resin film and the first film is further enhanced by the functional groups imparted to the laminated surface of the resin film.

[0010] Regarding the method for manufacturing the laminate for a package, the step of laminating the gas barrier layer is Si(OR 1 ) 4 , or R 2 Si(OR 3 ) 3 (OR 1 and OR 3 are hydrolyzable groups, and R 2 is an organic functional group), a silicon compound represented by the above, or a hydrolyzate of a silicon compound, and a water-soluble polymer having a hydroxyl group, and a second film containing the above is laminated on the surface of the first film opposite to the surface in contact with the surface of the resin film where the surface modification treatment is performed. The step may be included. According to the above configuration, the gas barrier property of the laminate can be further improved by reducing the water vapor permeability, oxygen permeability, etc. of the gas barrier layer.

Effects of the Invention

[0011] According to the present invention, the airtightness of a package including a laminate containing a resin film can be comprehensively improved.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0013] With reference to the drawings, an embodiment of a method for manufacturing a laminate for a package will be described. [Resin Film] With reference to FIG. 1, the configuration of a resin film 10, which is a resin film for a package, will be described. The resin film 10 made of polyester includes polyethylene terephthalate (PET). The PET resin is at least one of virgin PET newly synthesized from raw materials such as petroleum and recycled PET resin which is recycled PET. PET products to be recycled include used PET bottles. The recycled PET constituting the resin film 10 is at least one of PET recycled by mechanical recycling and PET recycled by chemical recycling.

[0014] Mechanical recycling includes the steps of pulverizing PET products into resin pieces, cleaning the resin pieces to remove surface dirt and foreign substances, and exposing the resin pieces at high temperature to remove contaminants remaining inside the resin. Chemical recycling includes the steps of pulverizing PET products into resin pieces, cleaning the resin pieces to remove surface dirt and foreign substances, depolymerizing the resin back to intermediate raw materials, and purifying and repolymerizing the intermediate raw materials. Compared with chemical recycling, mechanical recycling does not require large-scale equipment for chemical reactions, so the cost required for manufacturing recycled PET can be reduced. In addition, since the amount of carbon dioxide emissions can be reduced, the environmental impact is small. When reducing costs and environmental impact, the recycled PET used as the raw material for the resin film 10 is preferably PET recycled by mechanical recycling.

[0015] When the resin film 10 contains virgin PET in addition to recycled PET, from the viewpoint of reducing costs and environmental impact, the proportion of recycled PET is preferably 60% by weight or more and 100% by weight or less of the resin film 10.

[0016] In addition, the polyester constituting the resin film 10 contains a terephthalic acid component, an isophthalic acid component, and a naphthalenedicarboxylic acid component as the dicarboxylic acid component which is a repeating unit. The naphthalenedicarboxylic acid component is a polyvalent carboxylic acid component having a naphthalene skeleton, and examples thereof include 2,6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid. Note that it may contain 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid.

[0017] The isophthalic acid component and the naphthalenedicarboxylic acid component may be derived from recycled PET or virgin PET. Alternatively, they may be added in any of the manufacturing processes. Furthermore, dicarboxylic acid components such as adipic acid, and glycol components such as propylene glycol, 1,4-butanediol, tetramethylene glycol, neopentyl glycol, cyclohexanedimethanol, and diethylene glycol can also be included. Generally, PET resin is produced by polymerizing terephthalic acid as a dicarboxylic acid and ethylene glycol as a diol. However, the PET resin used for the resin film 10 is made of a resin obtained by copolymerizing isophthalic acid and naphthalenedicarboxylic acid with terephthalic acid, or a resin obtained by mixing polyethylene naphthalate resin with a resin obtained by copolymerizing terephthalic acid and isophthalic acid. That is, the isophthalic acid component and the naphthalenedicarboxylic acid component may be included as copolymer components with polyethylene terephthalate, or may be included as a polyester different from polyethylene terephthalate.

[0018] The average molecular weight of the PET resin contained in the resin film 10 is not particularly limited, but is preferably about 1,000 to 1,000,000, for example. Note that the resin film 10 may contain resins other than PET and various additives such as plasticizers.

[0019] The resin film 10 is composed of a single layer or a plurality of layers. When the resin film 10 is composed of a plurality of layers, the materials constituting each layer may be the same or different from each other. An example of a configuration in which the materials constituting each layer are different from each other is a laminate of a layer formed from recycled PET and a layer formed from virgin PET. Another example of a configuration in which the materials constituting each layer are different from each other is a laminate of a layer containing recycled PET at a first ratio with respect to virgin PET and a layer containing recycled PET at a second ratio different from the first ratio with respect to virgin PET.

[0020] The resin film 10 is subjected to a surface modification treatment on the laminated surface 12 where the gas barrier layer 11 is laminated. The surface modification treatment is a plasma treatment such as corona discharge treatment, reactive ion etching (RIE) which is a reactive ion etching, inductively coupled plasma (ICP) etching, ICP-RIE treatment, atmospheric pressure plasma treatment, frame treatment, etc. In other words, the resin film 10 has a surface modification layer 13 subjected to a surface modification treatment. The surface modification treatment may be applied only to the laminated surface 12, or may be applied to the surface opposite to the laminated surface 12 in addition to the laminated surface 12.

[0021] Hereinafter, the case where RIE treatment is used as the surface modification treatment will be described. Plasma is used in the RIE treatment. A chemical effect of imparting a functional group to the surface of the PET resin substrate can be obtained by radicals and ions generated in the plasma. In addition, a physical effect of removing surface impurities and increasing the surface roughness can be obtained by reactive ion etching. Therefore, due to these effects, the adhesion between the resin film 10 and the gas barrier layer 11 is improved, and peeling between the resin film 10 and the gas barrier layer 11 is less likely to occur even in a high-temperature and high-humidity environment. Therefore, the heat resistance of the entire laminate 20 is improved, and the occurrence of delamination between the resin film 10 and the gas barrier layer 11, the deterioration of the gas barrier property, etc. when heat treatment such as boiling treatment, retort treatment, and heat cooking is performed are suppressed.

[0022] The RIE treatment can be carried out using a known RIE-type plasma treatment apparatus. As the plasma treatment apparatus, a roll-to-roll in-line plasma treatment apparatus is preferable. As the roll-to-roll in-line plasma treatment apparatus, a planar type plasma treatment apparatus, a hollow anode type plasma treatment apparatus, etc. can be used.

[0023] The thickness of the resin film 10 is selected according to various characteristics required for the package, such as various environmental resistances such as heat and moisture, storage properties of the contents, filling properties of the contents, sealability, and printing resistance including marking. From the viewpoint of enhancing the processability of the resin film 10, for example, the thickness of the resin film 10 is preferably selected from the range of 3 μm or more and 100 μm or less, and more preferably selected from the range of 6 μm or more and 50 μm or less.

[0024] The method for forming the resin film 10 is a melt extrusion molding method or a melt co-extrusion molding method. The flow direction in the resin film 10 is the direction in which the PET resin is molded during the production of the resin film 10. The flow direction is also referred to as the MD (Machine Direction) or the longitudinal direction. The direction perpendicular to the flow direction is also referred to as the TD (Transverse Direction) or the transverse direction. When the resin film 10 is composed of a plurality of layers, the flow directions of the respective layers are the same.

[0025] The resin film 10 is an unstretched film, a uniaxially stretched film stretched at a predetermined magnification in the MD direction or the TD direction, or a biaxially stretched film stretched at a predetermined magnification sequentially or simultaneously in the MD direction and the TD direction. When the resin film 10 is composed of a plurality of layers, the stretching directions of the respective layers are the same.

[0026] [Laminate] Referring to FIG. 2, the laminate 20, which is a laminate for a package, will be described. The laminate 20 includes the resin film 10 and the gas barrier layer 11. The gas barrier layer 11 has a function of enhancing the gas barrier property in the laminate 20. Note that the ratio of the thickness of the resin film 10 and the thickness of the gas barrier layer 11 is not limited to the ratio shown in FIG. 2.

[0027] The gas barrier layer 11 is laminated on the laminated surface 12 of the resin film 10. The gas barrier layer 11 includes, for example, a vapor deposition film formed by chemical vapor deposition or physical vapor deposition. The vapor deposition film is an inorganic oxide film or a metal film. The inorganic substance contained in the inorganic oxide may be an oxide of, for example, silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, yttrium, etc. The metal may be, for example, aluminum, magnesium, tin, sodium, titanium, lead, zirconium, yttrium, gold, chromium, etc.

[0028] The method for forming the vapor deposition film may be, for example, a vacuum evaporation method, a sputtering method, an ion plating method, a plasma chemical vapor deposition method (CVD), etc. From the viewpoint of enhancing the productivity of the laminate, the method for forming the vapor deposition film is preferably the vacuum evaporation method. In the vacuum evaporation method, it is preferable to use any one of an electron beam heating method, a resistance heating method, and an induction heating method for heating the evaporation material. From the viewpoint of increasing the degree of freedom in the selectivity of the evaporation material, it is preferable to use the electron beam heating method. From the viewpoints of enhancing the adhesion between the vapor deposition film and the resin film 10 and enhancing the denseness of the vapor deposition film, in the vacuum evaporation method, it is possible to use a plasma assist method and an ion beam assist method. From the viewpoint of enhancing the transparency of the evaporation layer, the gas barrier layer 11 may be formed using a reactive evaporation method. In the reactive evaporation method, for example, a reactive gas such as oxygen gas is supplied to the film formation space.

[0029] The laminate 20 for forming a transparent package includes a vapor deposition film formed from an inorganic oxide. In particular, a vapor deposition film formed of aluminum oxide and silicon oxide is preferable. The laminate 20 for forming a package having light-shielding properties includes a vapor deposition film formed from a metal. In particular, a vapor deposition film formed of aluminum is preferable.

[0030] Note that the gas barrier layer 11 may be formed of a plurality of barrier layers. In this case, each barrier layer may be formed of the same material, or the plurality of barrier layers may include a barrier layer formed of a first material and a barrier layer formed of a second material different from the first material.

[0031] The thickness of the gas barrier layer 11 is not particularly limited. However, in the case of a vapor deposition film, it is, for example, 5 nm or more and 300 nm or less. When the thickness of the gas barrier layer 11 is 5 nm or more, the uniformity of the gas barrier layer 11 can be enhanced and the gas barrier layer 11 can have a sufficient thickness. Therefore, the gas barrier layer 11 can sufficiently exhibit its gas barrier function. On the other hand, when the thickness is 300 nm or less, the gas barrier layer 11 can retain its flexibility. As a result, cracks in the gas barrier layer 11 caused by external factors such as bending and stretching after film formation can be suppressed. Note that the thickness of the gas barrier layer 11 is appropriately selected according to the type of the inorganic compound forming the gas barrier layer 11 and the configuration of the laminate 20. From the viewpoint of enhancing the uniformity of the thickness of the gas barrier layer 11, it is more preferable that the thickness of the gas barrier layer 11 is included in the range of 10 nm or more and 150 nm or less. The vapor deposition film corresponds to the first coating film.

[0032] In addition to or instead of the above-described vapor deposition film, the gas barrier layer 11 may include a coating film having gas barrier properties. The coating film is formed of a material containing a resin. Hereinafter, an example in which the gas barrier layer 11 includes a coating film formed on a vapor deposition film of an inorganic oxide will be described. The coating film can protect the vapor deposition film, thereby enhancing the gas barrier property of the gas barrier layer. The coating film corresponds to the second coating film.

[0033] The coating film is formed from, for example, a water-soluble polymer and an inorganic compound. The water-soluble polymer may be, for example, polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, etc. From the viewpoint of enhancing the gas barrier property of the gas barrier layer 11, it is preferable that the water-soluble polymer is polyvinyl alcohol (PVA).

[0034] The inorganic compound contained in the coating film may be, for example, a silicon compound represented by Si(OR 1 ) 4 , or R 2 Si(OR 3 ) 3 , or a hydrolyzate of the silicon compound. In the chemical formula representing the silicon compound, OR 1 and OR 3 are hydrolyzable groups, and R 2 is an organic functional group. The inorganic compound may contain one or more silicon compounds or a hydrolyzate of the silicon compound. Further, when the coating film contains a silicon compound or a hydrolyzate of the silicon compound, the coating film may contain a coupling agent that binds an organic substance such as a water-soluble polymer and the silicon compound.

[0035] Si(OR 1 ) 4 may be, for example, tetraethoxysilane (Si(OC 2 H 5 ) 4 )(TEOS). TEOS is preferable in that it is relatively stable in an aqueous solvent after hydrolysis. Further, R 2 Si(OR 3 ) 3 The R 2 contained in is preferably selected from the group consisting of a vinyl group, an epoxy group, a methacryloxy group, a ureido group, and an isocyanate group. Further, the organic functional group R 2 may be a γ-glycidoxypropyl group or a β-(3,4 epoxycyclohexyl) group. Si(OR 1 ) 4 , or R 2Si(OR 3 ) 3 By adding a silicon compound represented by the formula or its hydrolyzate to the coating film, swelling of the gas barrier layer 11 can be prevented. In particular, those having a vinyl group, an epoxy group, a methacryloxy group, a ureido group, or an isocyanate group have further improved water resistance because the functional groups are hydrophobic.

[0036] The coating film is formed by applying a mixed solution obtained by mixing a solvent, a water-soluble polymer, a silicon compound or a hydrolyzate of a silicon compound, and additives such as a coupling agent onto the vapor deposition layer, followed by heating and drying. The solvent may be water or a mixed solvent of water and alcohol. When forming the mixed solution, first, the water-soluble polymer is dissolved in the solvent, and then the silicon compound or the hydrolyzate of the silicon compound is mixed. Note that the mixed solution may contain additives as long as the coating film formed using the mixed solution does not impair the gas barrier properties. The additives may be, for example, an isocyanate compound, a silane coupling agent, a dispersant, a stabilizer, a viscosity modifier, and a colorant.

[0037] The thickness of the coating film is, for example, 0.05 μm or more and 30 μm or less. When the gas barrier layer 11 includes a vapor deposition film and a coating film, in the laminate 20, the vapor deposition film is located on the resin film 10, and the coating film is located on the vapor deposition film. Thereby, the coating film is in contact with the vapor deposition film.

[0038] The vapor deposition film may be in contact with the laminated surface 12 of the resin film 10, and the coating film may be in contact with the vapor deposition film. Also, another layer may be located between the vapor deposition film and the coating film. Alternatively, a layer other than the coating film may be located between the vapor deposition film and the resin film 10.

[0039] In addition to the resin film 10 and the gas barrier layer 11, the laminate 20 may include a seal layer, an adhesive layer, a decorative layer, an information display layer, and the like. The seal layer contains a thermoplastic resin. When a package is formed using the laminate 20, the seal layer is melted by heat sealing. As a result, in two laminates 20, the end of one laminate 20 is fused to the end of the other laminate 20. Alternatively, in one laminate 20, the first part and the second part of the laminate 20 are fused together. The adhesive layer enhances the adhesion between the gas barrier layer 11 and the upper layer of the gas barrier layer 11, or between the gas barrier layer 11 and the lower layer of the gas barrier layer 11. The decorative layer and the information display layer display decorations and information formed by printing and the like.

[0040] The thickness of the laminate 20 may be selected according to various resistances required for the package formed using the laminate 20 and the processability required for the laminate 20. The thickness of the laminate 20 may be, for example, 30 μm or more and 300 μm or less.

[0041] For the formation of the laminate 20, the above-described film formation method, various coating methods, dry lamination method, extrusion lamination method, and the like may be used. [Package] Referring to FIG. 3, the package will be described.

[0042] The package 30 shown in FIG. 3 is formed from the laminate 20. The package 30 defines a space capable of accommodating an object to be packaged inside the package 30. In the example shown in FIG. 3, the package 30 has a bag shape. In the package 30, the ends are joined over the entire circumference, thereby sealing the package 30. In the package 30, the gas barrier layer 11 is located inside with respect to the resin film 10. The shape and size of the package 30 are not particularly limited. The shape and size of the package 30 may be designed according to the shape and size of the object to be packaged. The object to be packaged may be, for example, food, pharmaceuticals, cosmetics, or the like.

[0043] The method for joining the ends of the laminate 20 is not particularly limited. For example, the ends of the laminate 20 may be joined using heat sealing as described above, or may be joined by other methods. In the example shown in FIG. 3, the package 30 has a sealing portion 31 in which the end of the first laminate and the end of the second laminate are joined in two laminates 20.

[0044] Note that the package 30 is not limited to the bag shape shown in FIG. 3. For example, it may have a cylindrical shape, or a bag shape in which one end of the cylinder is sealed and the other end of the cylinder is open. Alternatively, the package 30 may include the laminate 20 only in part.

[0045] When a large number of packages 30 using the laminate 20 are mass-produced, a roll-to-roll apparatus is used, and while the laminate 20 is being conveyed by the roll-to-roll apparatus, a process for forming the package 30 is performed on the laminate 20. The laminate 20 is conveyed by the roll-to-roll apparatus along the flow direction of the resin film 10. At this time, the laminate 20 is conveyed by the roll-to-roll apparatus in a state of being pulled along the flow direction of the resin film 10. The resin film 10 is pulled along the flow direction with a stress such that the laminate 20 does not slack or bend, in order to enable the conveyance of the laminate 20 and to suppress the occurrence of wrinkles or the like in the package 30 formed using the laminate 20.

[0046] [Surface modification treatment] With reference to FIG. 4, an example of a method for a planar plasma processing apparatus to perform a surface modification process will be described. FIG. 4 is a diagram schematically showing a main part of a planar plasma processing apparatus 50. The planar plasma processing apparatus 50 includes a vacuum chamber, an electrode (cathode) 51 located in the vacuum chamber, and a cylindrical processing roll 52 located in the vacuum chamber. The electrode 51 is disposed inside the processing roll 52. The surface modification process is performed by introducing a gas to the outside of the processing roll 52 and transporting a base material 53, which is a resin film 10 before RIE processing, along the processing roll 52. At this time, when a voltage is applied to the electrode 51, plasma is generated outside the processing roll 52, and radicals in the plasma are attracted to the processing roll 52 side, which is the counter electrode, and act on the surface of the base material 53. In addition, a high self-bias is applied to the base material 53. Due to the high self-bias of the base material 53, ions 55 in the plasma are attracted to the base material 53 side, and a sputtering action (physical action) acts on the surface of the base material 53, and the RIE process is performed. When performing plasma processing with an apparatus in which the electrode 51 to which a voltage is applied is disposed outside the processing roll 52, the base material 53 will be disposed on the anode side. In this case, a high self-bias cannot be obtained, and only radicals act on the base material 53. By disposing the electrode 51 inside the processing roll 52 as shown in FIG. 4 in this type of processing apparatus, a chemical reaction can be generated by radicals, and the surface of the base material 53 can be sputtered by ions.

[0047] Next, with reference to FIG. 5, an example of a method for the hollow anode type plasma processing apparatus 60 to perform a surface modification process will be described. The hollow anode type plasma processing apparatus 60 shown in FIG. 5 includes a vacuum chamber, an electrode (anode) 61 located in the vacuum chamber, a processing roll 62 that functions as a counter electrode (cathode) of the electrode 61, a matching box 63 for impedance matching, a gas introduction nozzle 64, and shielding plates 65 disposed at both ends of the electrode 61. The electrode 61 has an opening, and the opening faces the processing roll 62. The processing roll 62 holds the substrate 53. The gas introduction nozzle 64 is disposed above the electrode 61 so that a gas for performing RIE processing can be introduced into the gap between the electrode 61 and the shielding plate 65 and the processing roll 62. The matching box 63 is disposed on the back surface of the electrode 61 and is connected to the electrode 61. The shielding plate 65 has a sectional shape along the outer circumference of the processing roll 62 and is disposed outside the processing roll 62 so as to face the processing roll 62. The area (S1) of the inner surface of the box-shaped electrode 61 is larger than the area (S2) of the surface to be processed of the substrate 53 facing through the opening (S1 > S2).

[0048] In the surface modification process, a gas is introduced into the gap between the electrode 61 and the shielding plate 65 of the hollow anode type plasma processing apparatus 60 and the processing roll 62, and the substrate 53 is conveyed along the processing roll 62. Then, when a voltage is applied from the matching box 63 to the electrode 61, plasma is generated inside the box-shaped electrode 61, and radicals in the plasma are attracted to the side of the processing roll 62, which is the counter electrode, and act on the surface of the substrate 53. Further, since the inner area of the electrode 61 is larger than the area of the surface of the substrate 53 to be processed, a high self-bias is generated in the substrate 53, and due to this high self-bias, ions in the plasma are attracted to the substrate 53 side, and the surface of the substrate 53 is sputtered. When the plasma is irradiated onto the substrate 53 with an apparatus in which the opening area of the electrode 61 is less than or equal to the area of the surface of the substrate 53 to be processed, a high self-bias cannot be obtained, and only radicals act on the substrate 53. The action of the radicals is only a chemical reaction, and the chemical reaction alone cannot sufficiently improve the adhesion between the substrate 53 and the gas barrier layer 11.

[0049] The hollow anode type plasma processing apparatus 60 may further be a magnetic assist - hollow anode type plasma processing apparatus in which a magnet is incorporated in the electrode 61 to form a magnetic electrode. Due to the magnetic field generated from the magnetic electrode, the plasma confinement effect can be further enhanced, and a high ion current density can be obtained with a large self - bias. As a result, a more powerful and stable RIE process can be performed at high speed.

[0050] As gas species for performing the RIE process, for example, argon, oxygen, nitrogen, and hydrogen can be used. These gases can be used alone or in combination of two or more. For the RIE process, it is not necessary to use the same type of plasma processing apparatus for two or more units. For example, the substrate can be processed by the planar type plasma processing apparatus 50 first, and then continuously processed using the hollow anode type plasma processing apparatus 60.

[0051] [Physical Properties of Resin Film] With reference to FIGS. 6 and 7, the resin film 10 will be described in more detail. FIGS. 6 and 7 are 1 showing the spectra of the resin film 10 measured by 1H - NMR. When the standard substance is 1,4 - bis - trimethylsilylbenzene - d4 and the chemical shift value of the signal of the standard substance is set to 0 ppm, three signals (peaks) derived from the isophthalic acid component having an isophthalic acid skeleton appear at 7.11 ppm to 7.25 ppm, a signal derived from the terephthalic acid component having a terephthalic acid skeleton appears at 7.40 ppm to 8.15 ppm, and a signal of the naphthalenedicarboxylic acid component having a naphthalenedicarboxylic acid skeleton appears at 8.34 ppm to 8.36 ppm. Also, a signal of ethylene glycol (EG) appears at 4.1 ppm to 4.8 ppm, and signals of diethylene glycol (DEG) appear at 3.75 ppm to 3.90 ppm and 4.25 ppm to 4.35 ppm. FIG. 7 is an enlarged view of the NMR spectrum. The signal appearing at 7.11 ppm to 7.25 ppm is a signal derived from the hydrogen at the position "A" indicated by the arrow among the hydrogens bonded to the aromatic ring having the isophthalic acid skeleton represented by the following general formula (1). [Chemical formula] The signal appearing at 7.40 ppm to 8.15 ppm is the signal derived from the four hydrogens bonded to the aromatic ring of the terephthalic acid skeleton represented by the following general formula (2). [Chemical formula] The signal appearing at 8.34 ppm to 8.36 ppm is the two signals derived from the hydrogen at the position "C" indicated by the arrow among the hydrogens bonded to the aromatic ring of the naphthalenedicarboxylic acid skeleton represented by the following general formula (3). [Chemical formula]

[0052] Note that the integrated value of the signal is the value obtained by integrating the relative intensities of the proton signals at each chemical shift when the chemical shift is changed by 0.01. Also, in the range of 7.11 ppm to 7.25 ppm derived from the isophthalic acid component, the integrated value I A is the sum of the integrated values of three signals.

[0053] When calculating the molar ratio of the isophthalic acid component from this spectrum, the molar ratio of the isophthalic acid component is 2×10 -1 mol% or more and 9×10 -1 mol% or less with respect to the total mass of the dicarboxylic acid component and the diol component.

[0054] The molar ratio of the isophthalic acid component is determined as follows. Among the spectra, the total integrated values (I sm ) of the signals corresponding to the terephthalic acid component, the isophthalic acid component, the naphthalenedicarboxylic acid component, the ethylene glycol component, and the diethylene glycol component are calculated and taken as "100 mol%". Further, the ratio of the integrated value (I sm ) of the signal of the isophthalic acid component at 7.11 ppm to 7.25 ppm to the total integrated value I A ) [(I A / I sm)×100〕 is taken as the molar ratio of the isophthalic acid component.

[0055] Also, the molar ratio of the naphthalenedicarboxylic acid component contained in the resin film 10 is 1×10 with respect to the total mass of the dicarboxylic acid component and the diol component. -2 mol% or more and 6×10 -2 mol% or less.

[0056] The molar ratio of the naphthalenedicarboxylic acid component is determined in the same manner as the molar ratio of the isophthalic acid component. That is, the total of the integral values of the signals corresponding to the terephthalic acid component, isophthalic acid component, naphthalenedicarboxylic acid component, ethylene glycol component, and diethylene glycol component (I sm ) is taken as "100 mol%". And, with respect to the total integral value I of the signals, the ratio [(I sm of the integral value (I B ) of the signal of the naphthalenedicarboxylic acid component at 8.34 ppm to 8.36 ppm B / I sm )×100〕 is taken as the molar ratio of the naphthalenedicarboxylic acid component.

[0057] When the molar ratio of the isophthalic acid component satisfies the above range, the resin film 10 has flexibility suitable as a film used for the package 30. Thereby, even when an external force such as friction, piercing, bending, or impact is applied to the package 30, the resin film 10 deforms following the external force to absorb the load, and cracks are less likely to be formed in the gas barrier layer 11 in contact with the resin film 10. When the molar ratio of the isophthalic acid component is less than 2×10 -1 mol%, the resin film 10 cannot obtain sufficient flexibility and the flex resistance decreases. When the flexibility of the resin film 10 is low, cracks are likely to occur in the gas barrier layer 11, and the number of cracks increases, or the width and length become large. As a result, it becomes difficult to keep the quality of the contents of the package 30 good. On the other hand, when the molar ratio of the isophthalic acid component is 9×10 -1 ​When it exceeds mol%, the heat resistance decreases, such as the melting point and softening temperature of the resin film 10 decreasing, and a uniform and dense vapor deposition film of aluminum oxide or silicon oxide cannot be formed on the resin film 10. Therefore, it becomes difficult to obtain the laminate 20 with high gas barrier properties. There is a possibility that the strength of the resin film 10 as a packaging resin film decreases. In order to adjust the content ratio of the isophthalic acid component of the resin film 10 so as to satisfy the above range, at the time of manufacturing the resin film 10, for example, adjusting the ratio of recycled PET to the whole PET, or adding an isophthalic acid component when polymerizing PET can be mentioned. Since PET bottles may contain an isophthalic acid component to improve processability, recycled PET tends to contain more isophthalic acid components than virgin PET. For this reason, when increasing the content ratio of the isophthalic acid component of the resin film 10, it is conceivable to increase the ratio of recycled PET.

[0058] By making the molar ratio of the naphthalenedicarboxylic acid component satisfy the above range, the surface orientation coefficient of the resin film 10 becomes high. The surface orientation coefficient is a measure of the orientation and crystallinity of the film and can be expressed by the following formula (1). Here, let the refractive index in the direction where the refractive index is maximum be n1, the refractive index in the direction orthogonal to the direction where the refractive index is maximum be n2, and the refractive index in the film thickness direction be n3.

[0059] Surface orientation coefficient Fn = (n1 + n2) / 2 - n3 …(1) By increasing the surface orientation coefficient of the resin film 10, the resin film 10 can maintain high gas barrier properties and the adhesion with the gas barrier layer 11 becomes good. The molar ratio of the naphthalenedicarboxylic acid component is 1×10 -2If it is less than mol%, the gas barrier property of the resin film 10 decreases, and when used as the package 30 and a load such as bending is applied, cracks are likely to be formed in the gas barrier layer 11. When the adhesion between the resin film 10 and the gas barrier layer 11 becomes low, the number of cracks generated in the gas barrier layer 11 increases, or the width and length of the cracks become large. When the number of such cracks increases, or the width and length become large, the quality of the contents of the package 30 cannot be kept good. When the molar ratio of the naphthalenedicarboxylic acid component is 6×10 -2 When it exceeds mol%, the adhesion to the gas barrier layer 11 decreases, and there is a possibility that the adhesion to the gas barrier layer 11 decreases to the extent that the gas barrier layer 11 peels off from the resin film 10. In order to adjust the content rate of the naphthalenedicarboxylic acid component of the resin film 10 so as to satisfy the above range, at the time of manufacturing the resin film 10, for example, adjusting the ratio of recycled PET to the whole PET, or adding the naphthalenedicarboxylic acid component when polymerizing PET can be mentioned. Recycled PET tends to contain more naphthalenedicarboxylic acid components than virgin PET. For this reason, when increasing the content of the naphthalenedicarboxylic acid component of the resin film 10, it is conceivable to increase the ratio of recycled PET. And when manufacturing the package 30, the content ratio of the isophthalic acid component and the content ratio of the naphthalenedicarboxylic acid component of the resin film 10 are measured in advance, and a resin film whose content ratios satisfy the conditions 1 and 2 respectively can be selected. Also, the molar ratio of the isophthalic acid component to the total amount of the dicarboxylic acid component and the diol component is 5×10 -1 mol% or more and 9×10 -1 mol% is as follows, and the molar ratio of the naphthalenedicarboxylic acid component is 4×10 -2 mol% or more and 6×10 -2 mol% By doing so, the airtightness of the laminate for a package with a gas barrier layer laminated can be further comprehensively enhanced.

[0060] As described above, according to one embodiment of the resin film, the laminate, and the package, the following effects can be obtained. (1) Since the molar ratio of the isophthalic acid component contained in the resin film 10 is 2×10 -1 mol% or more and 9×10 -1 mol% or less, the flexibility of the resin film is enhanced. By enhancing the flexibility of the resin film, the resin film follows an external force and is deformed to easily absorb a load, and the flex resistance of the laminate 20 and the package 30 for the package is enhanced. Further, since the molar ratio of the naphthalenedicarboxylic acid component is 1×10 -2 mol% or more and 6×10 -2 mol% or less, the surface orientation coefficient of the resin film becomes large, and the gas barrier property of the resin film 10 itself is enhanced. On the other hand, as the surface orientation coefficient becomes large, the adhesion between the resin film 10 and the gas barrier layer 11 may decrease. However, since the laminated surface 12 of the resin film 10 is subjected to plasma treatment, it is possible to achieve both an improvement in the gas barrier property of the resin film 10 and the adhesion of the gas barrier layer 11. Therefore, the airtightness of the resin film 10 laminated with the gas barrier layer 11 can be comprehensively enhanced.

[0061] (2) Since the surface modification treatment of the resin film 10 is RIE treatment, functional groups can be imparted to the surface of the resin film, and impurities attached to the surface of the resin film can be removed to increase the surface roughness. Thereby, the adhesion between the resin film 10 and the gas barrier layer 11 can be enhanced.

[0062] (3) According to the configuration in which the gas barrier layer 11 contains at least one of aluminum oxide and silicon oxide, a film having transparency can be formed on the resin film 10. Further, by reducing the water vapor permeability, the oxygen permeability, etc. of the gas barrier layer 11, the gas barrier property of the laminate can be improved.

[0063] (4) Si(OR 1 ) 4 , or R 2 Si(OR 3 )3 (OR 1 and OR 3 is a hydrolyzable group, and R 2 is an organic functional group), or a coating film which is a second film containing one or more hydrolyzates of the silicon compound and a water-soluble polymer having a hydroxyl group is laminated on the vapor deposition film. Thereby, oxygen permeability and the like can be increased, and the gas barrier property of the laminate 20 can be further improved.

[0064] [Examples] Examples 1 to 4 and Comparative Example 1 of the laminate provided with the resin film will be described. Note that these examples do not limit the present invention.

[0065] [Example 1] A resin film of Example 1 having a thickness of 12 μm was formed by laminating three resin layers by coextrusion. As the PET constituting the resin layer, PET in which recycled PET regenerated by mechanical recycling and virgin PET were mixed was used. The mass ratio of the recycled PET was 80% by weight of the resin film, and the ratio of the virgin PET was 20% by weight of the resin film. A part of this resin layer was cut, and the cut resin pieces were dissolved in trifluoroacetic acid as a solvent to prepare a sample for NMR measurement.

[0066] This sample was 1 measured by 1H-NMR (AVANCE NEO400, Bruker Japan) to obtain an NMR spectrum. The measurement conditions were an integration number of 256 scans, a flip angle of 30°, an acquisition time of 4.19 sec, and a waiting time of 2.00 sec. Using the obtained 1 1H-NMR spectrum, the total integral value I of the signals of the terephthalic acid component, isophthalic acid component, naphthalenedicarboxylic acid component, ethylene glycol component, and diethylene glycol component sm was calculated and taken as "100 mol%". Also, the integral value (I A ) of the signal of the isophthalic acid component at 7.11 ppm to 7.25 ppm and the integral value I of the signal of the naphthalenedicarboxylic acid component at 8.34 ppm to 8.36 ppmB were calculated. And the total I sm , the integral value I of the signal of the isophthalic acid component A , the integral value I of the signal of the naphthalenedicarboxylic acid component B were used to determine the molar ratio of the isophthalic acid component [(I A / I sm )×100%] and the molar ratio of the naphthalenedicarboxylic acid component [(I B / I sm )×100%].

[0067] The molar ratio of the isophthalic acid component was 9×10 -1 mol%, and the molar ratio of the naphthalenedicarboxylic acid component was 4×10 -2 mol%. RIE treatment was performed on one side of the resin film using a hollow anode type plasma processing apparatus. The applied power was 120 W, the treatment time was 0.1 sec, the treatment gas was argon, and the treatment unit pressure was 2.0 Pa. Also, a high-frequency power supply with a frequency of 13.56 MHz was used for the electrode.

[0068] A vapor deposition film was formed on this resin film subjected to RIE treatment. For the formation of the vapor deposition film, a vacuum evaporation apparatus using an electron beam heating method was used, and while introducing oxygen gas, a thin film of metallic aluminum was evaporated to form a vapor-deposited thin film composed of aluminum oxide with a thickness of 15 nm.

[0069] A coating film was formed on the vapor deposition film. A mixed solution obtained by mixing the following First Liquid, Second Liquid, and Third Liquid was applied onto the vapor deposition film by the gravure coating method and dried to obtain a coating film. The thickness of the coating film was 0.3 μm.

[0070] First Liquid: A hydrolysis solution with a solid content of 5 mass% (in terms of SiO 2 conversion) obtained by adding 17.9 g of tetraethoxysilane, 10 g of methanol, and 72.1 g of 0.1 N hydrochloric acid and stirring for 30 minutes for hydrolysis.

[0071] Second liquid: An aqueous solution prepared by mixing polyvinyl alcohol with a mass ratio of 5%, water, and methanol. The mass ratio of water to methanol was adjusted to 95:5. Third liquid: A hydrolyzed solution obtained by diluting 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate, which is a silane coupling agent, with water and isopropyl alcohol to a solid content of 5% by mass. The mass ratio of water to isopropyl alcohol was 1:1.

[0072] Note that the solid content weight ratios (by weight) of the first liquid, the second liquid, and the third liquid were 70:20:10, and the mixing ratio of the first liquid and the second liquid was 70% by weight: 30% by weight. As a result, a laminate including a resin film and a gas barrier layer including a vapor deposition layer and a coating film was obtained.

[0073] Furthermore, an adhesive layer made of a polyurethane-based adhesive was laminated on the coating film to a thickness of 3 μm, and unstretched polypropylene (CPP, thickness 70 μm) was laminated. This laminate was cut into a size of 210 mm × 297 mm, which is the size of A4 paper. After folding it in half with the gas barrier layer on the inside at the center of the long side, two sides were heat-sealed to produce a package having an opening. The heat sealing was performed using a tabletop degassing sealer V-301 (manufactured by Fuji Impulse Co., Ltd.) under the conditions of 190°C, 0.3 MPa, and 2 seconds. 150 mL of an aqueous cysteine solution with a concentration of 0.6% by mass was contained in this pouch. Then, one open side of the pouch was heat-sealed to obtain a sealed package.

[0074] [Example 2] The molar ratio of the isophthalic acid component contained in the resin film was 9 × 10 -1 mol%, and the molar ratio of the naphthalenedicarboxylic acid component was 6 × 10 -2 mol%. Otherwise, a resin film and a laminate including the resin film were produced in the same manner as in Example 1. Furthermore, a packaging bag and a package using the laminate were produced in the same manner as in Example 1.

[0075] [Example 3] The molar ratio of the isophthalic acid component contained in the resin film was 7×10 -1 mol%, and the molar ratio of the naphthalenedicarboxylic acid component was 6×10 -2 mol%. Otherwise, a resin film and a laminate provided with the resin film were produced in the same manner as in Example 1. Further, a packaging bag and a package using the laminate were produced in the same manner as in Example 1.

[0076] [Example 4] The molar ratio of isophthalic acid contained in the resin film was 5×10 -1 mol%, and the molar ratio of naphthalene-2,6-dicarboxylic acid was 4×10 -2 mol%. Otherwise, a resin film and a laminate provided with the resin film were produced in the same manner as in Example 1. Further, a packaging bag and a package using the laminate were produced in the same manner as in Example 1. Further, a packaging bag and a package using the laminate were produced in the same manner as in Example 1.

[0077] [Comparative Example 1] A resin film was formed in the same manner as in Example 1, except that PET (PET P60, manufactured by Toray Industries, Inc.) containing no isophthalic acid component or naphthalenedicarboxylic acid component was used. That is, signals at 7.11 ppm to 7.25 ppm and signals at 8.34 to 8.36 ppm were not detected. Otherwise, a resin film and a laminate provided with the resin film were produced in the same manner as in Example 1. Further, a packaging bag and a package using the laminate were produced in the same manner as in Example 1.

[0078] [Evaluation Method] [Surface Orientation Coefficient] The surface orientation coefficient ΔP was measured by a phase difference measurement method using a phase difference measuring device (manufactured by Oji Scientific Instruments Co., Ltd., KOBRA-WR). Specifically, a 40 mm × 40 mm region was set at the center in the TD direction and at the end in the TD direction of the resin film. Then, the phase difference was measured for this region at incident angles of 0° to 50° (10° pitch).

[0079] [Gas Barrier Property] Each package was subjected to retort treatment by heating at 110 °C for 110 minutes (heating condition 1) and at 135 °C for 30 minutes (heating condition 2) using a storage-type retort kettle. After retorting, the packages were cut to produce two test pieces, and the oxygen permeability and water vapor permeability were evaluated.

[0080] (Oxygen Permeability) For each sample, the oxygen permeability was measured using an oxygen permeability measuring device (product name: OX-TRAN-2 / 20, manufactured by MOCON). The measurement conditions were set at a temperature of 30 °C and a relative humidity of 70% RH. At this time, the methods compliant with JIS K 7126-2:2006 and ASTM D3985-81 were used. The unit in the measured value of oxygen permeability was set to [cc / m 2 ·day·atm].

[0081] (Water Vapor Permeability) For each sample, the water vapor permeability (g / (m 2 ·day)) was measured using a water vapor permeability measuring device (product name: PERMATRAN-W-3 / 31, manufactured by MOCON). The measurement conditions were set at a temperature of 40 °C and a relative humidity of 90% RH. The measurement method used was compliant with JIS K 7129-2:2019 and ASTM F1249-90.

[0082] [Lamination Strength (Dry Condition)] For the retorted packages, test pieces with a size of 15 mm × 200 mm were prepared. For the test pieces, the lamination strength (unit: N / 15 mm) was measured using a tensilon universal material testing machine ("Tensilon UMT-II-500 type" manufactured by Toyo Baldwin) under the conditions of a temperature of 23 °C and a relative humidity of 65%. The lamination strength was defined as the strength when the peeling speed was 200 mm / min and the peeling angle was 90 degrees. Note that the lamination strength is also referred to as the heat seal strength.

[0083] [Lamination Strength (Wet Condition)] In addition, for the package after retorting, test pieces similar to those for the laminate strength test under dry conditions were prepared. The test pieces were subjected to a wet heat treatment of being held in hot water at 130°C for 30 minutes, and the laminate strength was measured using a tensilon universal material testing machine under the conditions of a temperature of 23°C and a relative humidity of 65% while still in an undried state. The laminate strength was defined as the strength when water was applied between the laminated film and the heat-sealable resin layer and peeled at a peeling angle of 90 degrees with a tensile speed of 200 mm / min.

[0084] [Evaluation Results] The surface orientation coefficients, oxygen permeabilities, and water vapor permeabilities after retorting of the laminates of Examples 1 to 4 and the laminate of Comparative Example 1 were as shown in Table 1.

[0085] [Table 1] As shown in Table 1, the surface orientation coefficients of Examples 1 to 4 were larger in both the central row and the end row of the resin film than the surface orientation coefficient of Comparative Example 1. After retorting, the oxygen permeabilities of the resin films of Examples 1 to 4 were smaller than the oxygen permeabilities of the resin film of Comparative Example 1. Similarly, the water vapor permeabilities of the resin films of Examples 1 to 4 were smaller than the water vapor permeabilities of the resin film of Comparative Example 1. Also, regarding the laminate strength under dry conditions, Examples 1 to 4 were larger than Comparative Example 1. This suggested that the airtightness of the laminates of Examples 1 to 4 was enhanced compared to the laminate of Comparative Example 1. Similarly, regarding the laminate strength under wet conditions, Examples 1 to 4 were larger than Comparative Example 1. This suggested that the adhesiveness between the resin film and the gas barrier property of the laminates of Examples 1 to 4 was higher than that of the laminate of Comparative Example 1. [Explanation of Reference Numerals]

[0086] 10... Resin film 11... Gas barrier layer 20... Laminate 30... Package

Claims

1. A step of performing a surface modification treatment by reactive ion etching on a resin film containing polyethylene terephthalate, A step of laminating a gas barrier layer including a vapor deposition film having at least one of an inorganic oxide film and a metal film on the surface subjected to the surface modification treatment by chemical vapor deposition or physical vapor deposition, and having, The resin film contains a terephthalic acid component, an isophthalic acid component, and a naphthalenedicarboxylic acid component as dicarboxylic acid components of the polyester, and the molar ratio of the isophthalic acid component to the total amount of the dicarboxylic acid component and the diol component is 2×10 －１ mol% or more and 9×10 －１ mol% or less, and the molar ratio of the naphthalenedicarboxylic acid component is 1×10 －２ mol% or more and 6×10 －２ mol% or less A method for manufacturing a laminate for a package.

2. The molar ratio of the isophthalic acid component to the total amount of the dicarboxylic acid component and the diol component of the resin film is 5×10 －１ mol% or more and 9×10 －１ mol% or less, and the molar ratio of the naphthalenedicarboxylic acid component is 4×10 －２ mol% or more and 6×10 －２ mol% or less The method for manufacturing a laminate for a package according to claim 1.

3. The surface modification treatment is a reactive ion etching treatment The method for manufacturing a laminate for a package according to claim 1 or 2.

4. The step of laminating the gas barrier layer is, A step of laminating a first coating film, which is the inorganic oxide film containing at least one of aluminum oxide and silicon oxide, on the surface subjected to the surface modification treatment is included The method for manufacturing a laminate for a package according to any one of claims 1 to 3.

5. The step of laminating the gas barrier layer is, Si(OR １ ) ４ , or R ２ Si(OR ３ ) ３ (OR １ and OR ３ is a hydrolyzable group, R ２ is an organic functional group), or one or more types of hydrolyzates of the silicon compound, and a water-soluble polymer having a hydroxyl group. The method for manufacturing a laminate for a package according to claim 4.

6. The step of laminating the gas barrier layer is, A step of laminating the vapor deposition film having a thickness of 5 nm or more and 300 nm or less on the surface subjected to the surface modification treatment, and the method for manufacturing a laminate for a package according to any one of claims 1 to 3.

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