Resin film, laminate for package, and package

Abstract

To improve airtightness of a package formed of a laminate containing a resin film.SOLUTION: A laminate 20 includes a resin film 10 and a gas barrier layer 11. The resin film 10 contains polyethylene terephthalate. In a spectrum measured with 1H-NMR, a ratio (IA / I0) of an integrated value (IA), which is obtained by integrating signals derived from isophthalic acid and having a chemical shift value of 7.11 ppm or more and 7.25 ppm or less, to an integrated value (I0), which is obtained by integrating signals derived from a terephthalic acid component and having a chemical shift value of 7.40 ppm or more and 8.15 ppm or less, is 1×10-3 or more and 6×10-3 or less. A ratio (IB / I0) of an integrated value (IB), which is obtained by integrating signals derived from a naphthalenedicarboxylic acid and having a chemical shift value of 8.34 ppm or more and 8.36 ppm or less, to the integrated value (I0) is 1×10-4 or more and 5×10-4 or less.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a resin film and a laminate for a package.

Background Art

[0002] Resin films containing polyethylene terephthalate are widely used in 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, which is a property that 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.

Means for Solving the Problems

[0005] The resin film that solves the above problem is a resin film used to form a gas barrier layer, which contains polyethylene terephthalate containing a terephthalic acid component, an isophthalic acid component, and a naphthalenedicarboxylic acid component as a dicarboxylic acid component which is a repeating unit, and has a plane orientation coefficient of 0.17 or more. Furthermore, laminates containing resin films are required to not only have improved gas barrier properties but also have improved resistance to deformation, thereby comprehensively improving the airtightness of packages. The laminate for packaging that solves the above problems includes a resin film and a gas barrier layer laminated on the resin film, the resin film including polyethylene terephthalate, 1 In the spectrum measured by H-NMR, the integral value (I0) of the signal derived from the terephthalic acid component having a chemical shift value of 7.40 ppm or more and 8.15 ppm or less, and the integral value (I A ) and the ratio (I A / I0) is 1×10 -3 More than 6×10 -3 The integral value (I0) is a value obtained by integrating the signal originating from the naphthalenedicarboxylic acid component having a chemical shift value of 8.34 ppm or more and 8.36 ppm or less. B ) and the ratio (I B / I0) is 1×10 -4 5×10 or more -4 The following is the result.

[0006] A package that solves the above problem is a package including a laminate, the laminate including a resin film and a gas barrier layer laminated on the resin film, the resin film including polyethylene terephthalate, 1 In the spectrum measured by H-NMR, the integral value (I0) of the signal derived from the terephthalic acid component having a chemical shift value of 7.40 ppm or more and 8.15 ppm or less, and the integral value (I A ) and the ratio (IA / I0) is 1×10 -3 or more and 6×10 -3 or less, and the ratio (I B ) of the integrated value (I0) and the integrated value (I B / I0) obtained by integrating the signal derived from the naphthalenedicarboxylic acid component with a chemical shift value of 8.34 ppm or more and 8.36 ppm or less is 1×10 -4 or more and 5×10 -4 or less.

[0007] The resin film that solves the above problems is a resin film that constitutes a laminate for a packaging bag by laminating a gas barrier layer having gas barrier properties, includes polyethylene terephthalate, 1 In the spectrum measured by 1H-NMR, the ratio (I A ) of the integrated value (I0) obtained by integrating the signal derived from the terephthalic acid component with a chemical shift value of 7.40 ppm or more and 8.15 ppm or less and the integrated value (I A / I0) obtained by integrating the signal derived from the isophthalic acid component with a chemical shift value of 7.11 ppm or more and 7.25 ppm or less is 1×10 -3 or more and 6×10 -3 or less, and the ratio (I B ) of the integrated value (I0) and the integrated value (I B / I0) obtained by integrating the signal derived from the naphthalenedicarboxylic acid component with a chemical shift value of 8.34 ppm or more and 8.36 ppm or less is 1×10 -4 or more and 5×10 -4 or less.

[0008] According to each of the above configurations, the ratio (I A / I0) of the integrated value of the signal at 7.11 ppm or more and 7.25 ppm or less derived from the isophthalic acid component and the integrated value of the signal at 7.40 ppm or more and 8.15 ppm or less derived from the terephthalic acid component is 1×10 -3 or more and 6×10 -3Since it is as follows, 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. Further, the ratio (I B / I0) of the integral value of the signal at 8.34 ppm or more and 8.36 ppm or less derived from the naphthalenedicarboxylic acid component is 1×10 -4 or more and 5×10 -4 or less, so that 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 is enhanced. Therefore, the airtightness of the laminate with the gas barrier layer laminated can be comprehensively enhanced.

[0009] Regarding the laminate for the package, the ratio (I A ) of the integral value (I0) and the integral value (I A / I0) is 2×10 -3 or more and 4×10 -3 or less, and the ratio (I B ) of the integral value (I0) and the integral value (I B / I0) is 2×10 -4 or more and 3×10 -4 or less. According to the above configuration, the airtightness of the laminate resin film with the gas barrier layer laminated can be comprehensively enhanced. Regarding the laminate for the package, the gas barrier layer may contain at least one of aluminum oxide and silicon oxide. According to the above configuration, a film having transparency can be formed on the resin film. Further, by reducing the water vapor permeability, oxygen permeability, etc. of the gas barrier layer, the gas barrier property of the laminate can be improved. Also, the adhesion between the above resin film and the first film containing at least one of aluminum oxide and silicon oxide can be ensured.

[0010] Regarding the laminate for the package, the gas barrier layer is Si(OR 1 )4, or R 2 Si(OR 3 )3(OR1 and OR 3 is a hydrolyzable group, and R 2 is an organic functional group), or a film comprising at least one silicon compound represented by the formula, or a hydrolyzate of a silicon compound, and a water-soluble polymer having a hydroxyl group, may be provided.

[0011] 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. Further, according to each of the above configurations, the airtightness of a package including a laminate including a resin film can be comprehensively improved. [Advantages of the Invention]

[0012] According to the present invention, there can be provided a resin film having high gas barrier properties and high adhesion to a gas barrier layer, and a laminate for a package including the resin film. [Brief Description of the Drawings]

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0014] With reference to the drawings, an embodiment of a laminate for a package, a package, and a resin film for a package will be described. [Resin Film] Referring to FIG. 1, the configuration of the resin film 10, which is a resin film for a package, will be described. The resin film 10 made of polyester contains polyethylene terephthalate (PET). The PET resin is at least one of virgin PET newly synthesized from raw materials such as petroleum and recycled PET, which is recycled PET resin. 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.

[0015] Mechanical recycling includes a process of crushing PET products into resin pieces, a process of removing surface dirt and foreign substances by washing the resin pieces, and a process of exposing the resin pieces at high temperature to remove contaminants remaining inside the resin. Chemical recycling includes a process of crushing PET products into resin pieces, a process of washing the resin pieces to remove surface dirt and foreign substances, a process of depolymerizing the resin back to intermediate raw materials, and a process of 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 the production of recycled PET can be reduced. In addition, since the emission amount of carbon dioxide can be reduced, the environmental load is small. When reducing the cost and environmental load, the recycled PET used as the raw material of the resin film 10 is preferably PET recycled by mechanical recycling.

[0016] When the resin film 10 contains virgin PET in addition to recycled PET, from the viewpoint of reducing cost and environmental load, the proportion of recycled PET is preferably 60% by weight or more and 100% by weight or less of the resin film 10.

[0017] In addition, the polyester constituting the resin film 10 contains a terephthalic acid component, an isophthalic acid component, and a naphthalenedicarboxylic acid component as dicarboxylic acid components that are repeating units. 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. In addition, it may contain 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid.

[0018] 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, it is also possible to include a dicarboxylic acid component such as adipic acid and a glycol component such as propylene glycol, 1,4-butanediol, tetramethylene glycol, neopentyl glycol, cyclohexanedimethanol, and diethylene glycol. Generally, PET resin is produced by polymerizing terephthalic acid, which is a dicarboxylic acid, and ethylene glycol, which is 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 a copolymerization component with polyethylene terephthalate, or may be included as a polyester different from polyethylene terephthalate.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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 direction of each layer is the same.

[0023] 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 direction of each layer is the same.

[0024] [Laminate] Referring to FIG. 2, the laminate 20, which is a laminate for a package, will be described. The laminate 20 includes a resin film 10 and a 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 to the thickness of the gas barrier layer 11 is not limited to the ratio shown in FIG. 2.

[0025] 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, for example, an oxide of 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.

[0026] 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, a reactive gas such as oxygen gas is supplied to the film formation space, for example.

[0027] 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 suitable. 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 suitable.

[0028] Note that the gas barrier layer 11 may be formed from a plurality of barrier layers. In this case, each barrier layer may be formed from the same material, or the plurality of barrier layers may include a barrier layer formed from a first material and a barrier layer formed from a second material different from the first material.

[0029] The thickness of the gas barrier layer 11 is not particularly limited, but in the case of a vapor deposition film, it is, for example, 5 nm or more and 300 nm or less. By the thickness of the gas barrier layer 11 being 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, by the thickness being 300 nm or less, the gas barrier layer 11 can maintain flexibility. Thereby, cracks in the gas barrier layer 11 due to 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 inorganic compound forming the gas barrier layer 11 and the configuration of the laminate 20. From the viewpoint of enhancing the uniformity in 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.

[0030] 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 from a material containing a resin. The coating film can protect the vapor deposition film, thereby enhancing the gas barrier properties of the gas barrier layer.

[0031] 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).

[0032] The inorganic compound contained in the coating film is, 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.

[0033] Si(OR 1 )4 may be, for example, tetraethoxysilane (Si(OC2H5)4) (TEOS). TEOS is preferable in that it is relatively stable in an aqueous solvent after hydrolysis. Also, R 2 in R 3 Si(OR 2 )3 is preferably selected from the group consisting of a vinyl group, an epoxy group, a methacryloxy group, a ureido group, and an isocyanate group.

[0034] The coating film is formed by applying a mixed solution of a solvent, a water-soluble polymer, and a silicon compound or a hydrolyzate of a silicon compound onto the vapor deposition layer and then undergoing 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 within a range where the coating film formed using the mixed solution does not impair the gas barrier property. The additives may be, for example, isocyanate compounds, silane coupling agents, dispersants, stabilizers, viscosity modifiers, and colorants, etc.

[0035] When the water-soluble polymer is PVA, the ratio of the mass of PVA to the mass of the total solid content of the mixed solution is preferably 20% by mass or more and 50% by mass or less, and more preferably 25% by mass or more and 40% by mass or less. When PVA is contained at 20% by mass or more, the flexibility of the coating film is maintained. Therefore, the formation of the coating film is easy. Also, when PVA is contained at 50% by mass or less, the gas barrier layer 11 can have sufficient barrier properties.

[0036] 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 may be located on the resin film 10 and the coating film may be located on the vapor deposition film. Thereby, the coating film is in contact with the vapor deposition film. Or, the coating film may be located on the resin film 10.

[0037] From the viewpoint of strengthening the adhesion between the resin film 10 and the gas barrier layer 11, surface treatments such as plasma treatment and corona treatment may be performed on the surface of the resin film 10 where the gas barrier layer 11 is formed. When the gas barrier layer 11 is formed from an inorganic oxide, an anchor coat layer may be located between the resin film 10 and the gas barrier layer 11. According to the surface treatment and the anchor coat layer, the adhesion between the resin film 10 and the vapor deposition layer after heat sterilization, and the barrier property of the laminate 20, etc. can be enhanced.

[0038] Note that, in addition to the above-described vapor deposition film and coating film, or instead of at least one of the above-described vapor deposition film and coating film, the gas barrier layer 11 may include a metal foil, a layer formed from a metal nitride, and the like. When the gas barrier layer 11 includes one or more layers other than the vapor deposition film and the coating film, another layer may be located between the vapor deposition film and the coating film. Alternatively, another layer other than the coating film may be located between the vapor deposition film and the resin film.

[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. The seal layer is melted by heat sealing when a package is formed using the laminate 20. 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 portion and the second portion of the laminate 20 are fused. 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.

[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 forming 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 inside the package 30 capable of accommodating an object to be packaged. 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, etc.

[0043] The method of 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 the 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 is open. Alternatively, the package 30 may include the laminate 20 only in part.

[0045] When the package 30 using the laminate 20 is mass-produced, a roll-to-roll device is used, and while the laminate 20 is being conveyed by the roll-to-roll device, a process for forming the package 30 is applied to the laminate 20. The laminate 20 is conveyed by the roll-to-roll device along the flow direction of the resin film 10. At this time, the laminate 20 is conveyed by the roll-to-roll device 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, both in enabling the conveyance of the laminate 20 and in suppressing the occurrence of wrinkles and the like in the package 30 formed using the laminate 20.

[0046] Physical properties of the resin film Referring to FIGS. 4 and 5, the physical properties of the resin film 10 will be described. FIGS. 4 and 5 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 derived from the naphthalenedicarboxylic acid component having a naphthalenedicarboxylic acid skeleton appears at 8.34 ppm to 8.36 ppm. FIG. 5 is an enlarged view of the spectrum. In the present embodiment, the signal appearing at 7.11 ppm to 7.25 ppm is the signal indicated by "A" in FIG. 5, and is a signal derived from the hydrogen at the position "A" indicated by the arrow among the hydrogens bonded to the aromatic ring having an isophthalic acid skeleton represented by the following general formula (1).

Chemical formula

Chemical formula

Chemical formula

[0047] The resin film 10 satisfies the following Condition 1 and Condition 2 in order to enhance the flexibility of the resin film 10 itself. · The integral value (I A ) which is the area of the signal derived from the isophthalic acid component at 7.11 ppm to 7.25 ppm and the ratio (I A / I0) of the integral value (I0) which is the area of the signal derived from the terephthalic acid component at 7.40 ppm to 8.15 ppm is 1×10 -3 or more and 6×10 -3 or less (Condition 1).

[0048] · 1 The ratio (I B / I0) of the integral value (I B ) which is the area of the signal derived from the naphthalenedicarboxylic acid component at 8.34 ppm to 8.36 ppm measured by 1H-NMR and the integral value (I0) which is the area of the signal derived from the terephthalic acid component at 7.40 ppm to 8.15 ppm is 1×10 -4 or more and 5×10 -4 or less (Condition 2).

[0049] The integral value of the signal is a value obtained by integrating the relative intensities of the proton signals at each chemical shift when the chemical shift is changed by 0.01. Further, in the range of 7.11 ppm to 7.25 ppm derived from the isophthalic acid component, the integral value I A is the sum of the integral values of three signals.

[0050] By satisfying Condition 1, the content of the isophthalic acid component in the resin film 10 is within an appropriate range. As a result, the resin film 10 has flexibility suitable for the 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. The ratio (I A / I0) of the integral value I A is 1×10 -3If it is less than that, since the content of the isophthalic acid component is insufficient, the resin film 10 cannot obtain high 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 of the cracks increase. As a result, it becomes difficult to maintain the quality of the contents of the package 30. On the other hand, the integrated value I A The ratio of (I A / I0) exceeds 6×10 -3 , 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 a laminate 20 with high gas barrier properties. In order to adjust the content of the isophthalic acid component of the resin film 10 to satisfy the above condition 1, when 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 of the isophthalic acid component of the resin film 10, it is conceivable to increase the ratio of recycled PET.

[0051] By satisfying condition 2, the content of the naphthalenedicarboxylic acid component falls within an appropriate range, and the surface orientation coefficient of the resin film 10 increases. The surface orientation coefficient is a measure of the orientation and crystallinity of the film, and can be expressed by the following formula (1). Let the refractive index in the direction where the refractive index is maximum be n1, the refractive index in the direction perpendicular to the direction where the refractive index is maximum be n2, and the refractive index in the thickness direction of the film be n3.

[0052] Surface orientation coefficient Fn=(n1 + n2) / 2 - n3 …(1) By increasing the surface orientation coefficient of the resin film 10, the resin film 10 itself can maintain high gas barrier properties and the adhesion with the gas barrier layer 11 becomes good. The integrated value IB The ratio (I B / I0) is 1×10 -4 If it is less than, the gas barrier property of the resin film 10 decreases, and when it is 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 become large. When the number of such cracks increases or the width and length become large, it is difficult to keep the quality of the contents of the package 30 good. The integrated value I B The ratio (I B / I0) is 5×10 -4 If it exceeds, there is a possibility that the adhesion with 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 of the naphthalenedicarboxylic acid component of the resin film 10 so as to satisfy the above condition 2, at the time of manufacturing the resin film 10, for example, adjusting the ratio of recycled PET to the whole PET, or adding a 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 can be measured in advance, and a resin film whose content ratios satisfy conditions 1 and 2 can be selected.

[0053] The ratio (I A ) of the integrated value at 7.11 ppm to 7.25 ppm (I A ) and the ratio (I B ) of the integrated value at 8.34 ppm to 8.36 ppm (I BBy manufacturing the package 30 using the resin film 10 with the above range for (I0), the flex resistance of the package 30 can be enhanced, and the adhesion between the resin film 10 and the gas barrier layer 11 can be maintained well. Also, the ratio (I A ) of the integral value (I0) and the said integral value (I A / I0) is 2×10 -3 or more and 4×10 -3 or less, and when the ratio (I B ) of the integral value (I0) and the said integral value (I B / I0) is 2×10 -4 or more and 3×10 -4 or less, the airtightness of the resin film 10 with the gas barrier layer 11 further laminated can be comprehensively enhanced.

[0054] As described above, according to one embodiment of the resin film for a package, the laminate for a package, and the package, the following effects can be obtained. (1) Since the ratio (I A ) of the integral value of the signal at 7.11 ppm to 7.25 ppm derived from the isophthalic acid component and the integral value of the signal at 7.40 ppm to 8.15 ppm derived from the terephthalic acid (I -3 / I0) is 1×10 -3 or more and 6×10 B or less, the flexibility of the resin film 10 is enhanced. By enhancing the flexibility of the resin film 10, the resin film 10 becomes liable to deform following an external force, and the flex resistance of the laminate 20 for a package and the package 30 is enhanced. Also, since the ratio (I -4 ) of the integral value of the signal at 8.34 ppm to 8.36 ppm derived from the naphthalenedicarboxylic acid component (I -4 / I0) is 1×10

[0055] -4 or more and 5×10 -4 or less, while increasing the surface orientation coefficient of the resin film 10, peeling between the resin film 10 and the gas barrier layer 11 can be suppressed. By increasing the surface orientation coefficient, the gas barrier property of the resin film 10 itself is enhanced. Therefore, the airtightness of the resin film 10 with the gas barrier layer 11 laminated can be comprehensively enhanced.(2) 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, oxygen permeability, etc. of the gas barrier layer 11, the gas barrier property of the laminate can be improved. Also, since the ratio (I B / I0) of the integral value of the signal derived from the naphthalenedicarboxylic acid component of the resin film 10 is 5×10 -4 or less, adhesion with the first film containing at least one of aluminum oxide and silicon oxide can be ensured.

[0056] (3) According to the configuration in which the gas barrier layer 11 contains one or more silicon compounds represented by Si(OR 1 )4 or R 2 Si(OR 3 )3, or hydrolyzates of the silicon compounds, and a water-soluble polymer having a hydroxyl group, the water vapor permeability, oxygen permeability, etc. of the gas barrier layer 11 are lowered. Thereby, the gas barrier property of the laminate 20 can be further improved.

[0057] [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.

[0058] [Example 1] A resin film having a thickness of 12 μm with three resin layers laminated by coextrusion was prepared. 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 mass 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 piece was dissolved in trifluoroacetic acid as a solvent to prepare a sample for NMR measurement.

[0059] This sample was, 1It was measured by 1H-NMR (AVANCE NEO400, Bruker Japan) to obtain an NMR spectrum. The measurement conditions were set as follows: the number of integrations was 256 scans, the flip angle was 30°, the acquisition time was 4.19 sec, and the waiting time was 2.00 sec. The ratio (I A ) of the integral value (I A ) of the signal appearing around 7.20 ppm to the integral value (I0) of the signal appearing around 7.80 ppm was 4×10 -3 . Also, the ratio (I B ) of the integral value (I B ) at 8.35 ppm to the integral value (I0) was 2×10 -4 .

[0060] On this resin film, a vacuum deposition apparatus using an electron beam heating method was used, and while introducing oxygen gas therein, a thin film of metallic aluminum was evaporated to form a vapor deposition film composed of aluminum oxide with a thickness of 15 nm.

[0061] Furthermore, 72.1 g of hydrochloric acid (0.1 N) was added to 17.9 g of tetraethoxysilane and 10 g of methanol, and the mixture was stirred for 30 minutes for hydrolysis to obtain a hydrolysis solution as the first liquid. Also, an aqueous solution obtained by mixing 5% by mass of polyvinyl alcohol and 95% by mass of water / methanol = 95 / 5 (mass ratio) was used as the second liquid. Then, a solution obtained by mixing the first liquid and the second liquid at a ratio of 70:30 in terms of the weight ratio of the solid content was applied to the resin film on which the vapor deposition film was formed using gravure coating and dried to obtain a laminate.

[0062] [Example 2] In the 1 1H-NMR spectrum of the resin film, the ratio (I A ) of the integral value (I A ) of the signal appearing around 7.20 ppm to the integral value (I0) of the signal appearing around 7.80 ppm was 4×10 -3 . Also, the ratio (I B ) of the integral value (I B ) at 8.35 ppm to the integral value (I0) was 3×10 -4It was. Except for this, a resin film and a laminate including the resin film were produced in the same manner as in Example 1.

[0063] [Example 3] In the 1 1H-NMR spectrum of the resin film, the ratio (I A / I0) of the integral value (I0) of the signal appearing around 7.80 ppm to the integral value (I A ) of the signal appearing around 7.20 ppm was 3×10 -3 . Also, the ratio (I B / I0) of the integral value (I0) to the integral value (I B ) at 8.35 ppm was 3×10 -4 . Except for this, a resin film and a laminate including the resin film were produced in the same manner as in Example 1.

[0064] [Example 4] In the 1 1H-NMR spectrum of the resin film, the ratio (I A / I0) of the integral value (I0) of the signal appearing around 7.80 ppm to the integral value (I A ) of the signal appearing around 7.20 ppm was 2×10 -3 . Also, the ratio (I B / I0) of the integral value (I0) to the integral value (I B ) at 8.35 ppm was 2×10 -4 . Except for this, a resin film and a laminate including the resin film were produced in the same manner as in Example 1.

[0065] [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 and naphthalenedicarboxylic acid component was used. That is, the signals at 7.11 ppm to 7.25 ppm and at 8.34 to 8.36 ppm were not detected. Except for this, a resin film and a laminate including the resin film were produced in the same manner as in Example 1.

[0066] [Evaluation Method] [In-plane alignment coefficient] The in-plane alignment coefficient ΔP was measured by the 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 area was set at the center and the end in the TD direction of the resin film. Then, the phase difference was measured for this area at incident angles of 0° to 50° (10° pitch).

[0067] [Gas barrier property] Two test pieces were prepared from each of the laminates of Examples 1 to 4 and the laminate of Comparative Example 1, and the gas barrier property after the gelbo flex test was evaluated.

[0068] (Gelbo flex test) The gelbo flex test of each test piece was performed using a flexibility evaluation device (manufactured by Tester Sangyo Co., Ltd., Gelbo Flex Tester). At this time, each test piece was attached to the fixed head of the flexibility evaluation device so as to have a cylindrical shape. Specifically, both ends of each test piece were held by the fixed head, and the initial gripping interval was set to 175 mm. Then, the stroke was set to 87.5 mm, the twist was set to 440°, and a reciprocating motion of twisting and releasing the twist of each test piece was performed 100 times at a speed of 40 times / min.

[0069] (Oxygen permeability) For the laminates of Examples 1 to 4 and Comparative Example 1, the oxygen permeability was measured using an oxygen permeability measuring device (trade name: OX-TRAN-2 / 20, manufactured by MOCON). The measurement conditions were a temperature of 30°C and a relative humidity of 70%RH. At this time, the methods conforming to JIS K 7126-2:2006 and ASTM D3985-81 were used. The unit in the measured value of the oxygen permeability was set to [cc / m 2 ·day·atm].[[]END]]

[0070] (Water vapor permeability) For the laminates of Examples 1 to 4 and Comparative Example 1, the water vapor permeability (g / (m2 ·day) was measured. The measurement conditions were set as a temperature of 40°C and a relative humidity of 90%RH. The measurement method used was in accordance with JIS K 7129-2:2019 and ASTM F1249-90.

[0071] [Evaluation Results] The surface orientation coefficient, oxygen permeability, and water vapor permeability of the laminates of Examples 1 to 4 and the laminate of Comparative Example 1 were as shown in Table 1 below.

[0072] [Table 1] As shown in Table 1, the surface orientation coefficients of Examples 1 to 4 were larger than that of Comparative Example 1 in both the central row and the end row of the resin film. The oxygen permeability of the resin films of Examples 1 to 4 after the gelbo flex test was smaller than the oxidation permeability of the resin layer of Comparative Example 1. Similarly, the water vapor permeability of the resin films of Examples 1 to 4 after the gelbo flex test was smaller than the water vapor permeability of the resin layer of Comparative Example 1. That is, it was suggested that the resin films of Examples 1 to 4 maintained high airtightness even after an external force was applied, compared with the resin film of Comparative Example 1. Therefore, by adopting a resin film that satisfies Conditions 1 and 2 described in the above embodiment as the resin film for the package, a package excellent in flex resistance and excellent in adhesion to the gas barrier layer can be produced. [Explanation of Reference Numerals]

[0073] 10... Resin film 11... Gas barrier layer 20... Laminate 30... Package

Claims

Claim 1 A resin film used for forming a gas barrier layer, including polyethylene terephthalate containing a terephthalic acid component, an isophthalic acid component, and a naphthalenedicarboxylic acid component as a dicarboxylic acid component which is a repeating unit, a resin film having a surface orientation coefficient of 0.17 or more. Claim 2 The resin film according to claim 1, wherein the polyethylene terephthalate includes at least one of PET recycled by mechanical recycling and PET recycled by chemical recycling.

3. １ In the spectrum measured by 1H-NMR, the chemical shift value is 7.40 ppm or more and 8.15 ppm or less, and the integrated value (I ０ ) obtained by integrating the signal derived from the terephthalic acid component, and the chemical shift value is 8.34 ppm or more and 8.36 ppm or less, and the integrated value (I Ｂ ) obtained by integrating the signal derived from the naphthalenedicarboxylic acid component, and the ratio (I Ｂ / I ０ ) is 2×10 －４ or more and 3×10 －４ or less. The resin film according to claim 1. Claim 4 The integrated value (I ０ ), and the integrated value (I Ａ ) obtained by integrating the signal derived from the isophthalic acid component with a chemical shift value of 7.11 ppm or more and 7.25 ppm or less, and the ratio (I Ａ / I ０ ) is 2×10 －３ or more and 4×10 －３ or less. The resin film according to claim 3. Claim 5 The resin film according to claim 1, wherein the polyethylene terephthalate has a molecular weight of 1,000 or more and 1,000,000 or less and a thickness of 6 μm or more and 50 μm or less. Claim 6 The resin film according to claim 1, having a decorative layer or an information display layer formed by printing. Claim 7 A laminate for a package, including the resin film according to any one of claims 1 to 6 and a gas barrier layer having at least one of an inorganic oxide film and a metal film.

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