Barrier film, laminate, packaging container, and packaging product

Abstract

A barrier film provided with a base material layer containing a polypropylene resin, an anchor coat layer, and an inorganic oxide layer in this order. The substrate layer has a contact layer in contact with the anchor coating. When the softening temperatures of the anchor coating and the contact layer are determined by local thermal analysis, the softening temperature T1 of the contact layer is lower than the softening temperature T2 of the anchor coating.

Description

Technical Field

[0001] The present disclosure relates to barrier films, laminates, packaging containers, and packaged products. Background Art

[0002] Barrier films are widely used as packaging materials for foods, medical products, and other products that undergo heat sterilization processes such as boiling and retorting. Barrier films used in such packaging materials include a substrate layer, an anchor coating layer, and an inorganic oxide layer. For transparency, mechanical strength, and heat resistance, a substrate layer composed of polypropylene resin is often used.

[0003] Patent Document 1 below discloses a transparent laminate comprising a substrate formed of a stretched polypropylene film, a transparent primer layer comprising a mixture of an acrylic resin and an isocyanate resin, and a thin film layer comprising an inorganic compound, laminated in this order. Patent Document 1 also discloses a heat-sealable laminate comprising a transparent laminate comprising a thin film layer comprising an inorganic compound, and a gas-barrier coating and a heat-sealable resin layer (sealant layer) laminated on the thin film layer comprising an inorganic compound.

[0004] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 10-264292 Summary of the Invention

[0005] Problems to be solved by the invention However, the transparent laminate described in Patent Document 1 has room for improvement in terms of adhesion to the sealant layer after heat sterilization.

[0006] Therefore, an object of the present disclosure is to provide a barrier film, a laminate, a packaging container, and a packaging product that have excellent lamination strength with other films even after heat sterilization.

[0007] Means for solving problems The inventors of the present disclosure conducted research to address the aforementioned issues. When a barrier film comprising a substrate layer containing a polypropylene resin, an anchor coating, and an inorganic oxide layer is bonded to another film such as a sealant layer and then subjected to heat sterilization, the substrate layer subsequently experiences shrinkage. The inventors believe that in this case, the shrinkage stress generated in the substrate layer is transmitted to the inorganic oxide layer via the anchor coating, causing deformation between the inorganic oxide layer and the other film. Therefore, the inventors conducted further and in-depth research focusing on this aspect and discovered that the aforementioned issues can be addressed through the present disclosure below.

[0008] That is, one aspect of the present disclosure provides a barrier film comprising, in sequence, a substrate layer containing a polypropylene resin, an anchor coating layer, and an inorganic oxide layer, wherein the substrate layer has a contact layer in contact with the anchor coating layer, wherein, when the softening temperatures of the anchor coating layer and the contact layer are measured using local thermal analysis, the softening temperature T1 of the contact layer is lower than the softening temperature T2 of the anchor coating layer.

[0009] According to the barrier film, even after heat sterilization, the barrier film has excellent lamination strength with other films.

[0010] The inventors of the present disclosure presume that the reasons for obtaining the above-mentioned effects are as described below.

[0011] Specifically, when a barrier film comprising a substrate layer containing a polypropylene resin, an anchor coating layer, and an inorganic oxide layer is bonded to another film such as a sealant layer and then subjected to heat sterilization, the substrate layer subsequently shrinks, and the resulting shrinkage stress is transferred to the inorganic oxide layer via the anchor coating layer. In this case, the barrier film of the present disclosure includes a contact layer having a softening temperature T1 lower than the softening temperature T2 of the anchor coating layer and being more flexible than the anchor coating layer. Therefore, the shrinkage stress applied from the substrate layer to the anchor coating layer is mitigated by the contact layer. Therefore, deformation is less likely to occur between the inorganic oxide layer and the other film, and a decrease in the adhesion between the other film and the barrier film can be suppressed. As a result, the inventors of the present disclosure speculate that the barrier film described above exhibits excellent lamination strength with other films even after heat sterilization.

[0012] In the barrier film, the anchor coating layer preferably has a softening temperature T2 within a range of 140° C. to 195° C.

[0013] A softening temperature T2 of 140°C or higher improves the heat resistance of the anchor coating layer. This minimizes deformation of the anchor coating layer even at high temperatures during heat sterilization, such as retorting, and reduces damage to the inorganic oxide layer. Consequently, the barrier film can achieve further improved oxygen permeability even after heat sterilization. Furthermore, by setting the softening temperature T2 of the anchor coating layer below 195°C, the anchor coating layer does not become excessively hard, effectively achieving durability against deformation of the barrier film during heat sterilization, such as retorting, and preventing damage to the inorganic oxide layer.

[0014] In the barrier film, the substrate layer may further include a core layer on the side of the contact layer opposite to the anchor coating layer, the contact layer may be a skin layer, and the softening temperature T1 of the contact layer may be lower than the softening temperature T3 of the core layer.

[0015] In the barrier film, T2-T1 is preferably 70°C or lower.

[0016] When T2-T1 is 70°C or lower, the difference in flexibility between the contact layer and the anchor coating layer is unlikely to increase, and the adhesion between the contact layer and the anchor coating layer is unlikely to decrease.

[0017] In the barrier film, the contact layer may include a copolymer of propylene and α-olefin.

[0018] In this case, the difference between the softening temperature T1 of the skin layer and the softening temperature T2 of the anchor coating layer is easily increased.

[0019] In the barrier film, the anchor coating layer may contain a polyurethane resin.

[0020] When the anchor coating layer contains a polyurethane resin, the barrier film can have high heat resistance and high durability against heat sterilization.

[0021] In the barrier film, the anchor coating layer may have a thickness of 0.05 to 2 μm.

[0022] In this case, the decrease in water vapor barrier properties when an external force such as stretching is applied to the barrier film can be further suppressed. In addition, the flexibility of the barrier film is further improved, and the oxygen barrier properties of the barrier film after harsh treatment can be further improved.

[0023] Another aspect of the present disclosure provides a laminate including the barrier film and a sealant layer.

[0024] According to the above laminate, the barrier film maintains excellent lamination strength with the sealant layer, which is another film, even after heat sterilization. Therefore, the occurrence of interlayer delamination can be suppressed even after heat sterilization. In other words, the above laminate can maintain excellent interlayer adhesion even after heat sterilization.

[0025] The laminate may further include a second base material layer on the surface of the barrier film opposite to the sealant layer, wherein the second base material layer includes a polyolefin resin.

[0026] The laminate may include the second substrate layer, the barrier film, and the sealant layer in sequence, wherein the substrate layer of the barrier film is the first substrate layer, and the second substrate layer, the first substrate layer, and the sealant layer all comprise polypropylene films, and in an X-ray diffraction pattern obtained by measuring the second substrate layer using X-ray diffraction, the intensity I of the (110) peak is 110 The intensity of the peak relative to the (040) plane is I 040 The ratio, that is, the peak intensity ratio A, is 0.75 or more.

[0027] This laminate has excellent recyclability and can have excellent interlayer adhesion even after heat sterilization treatment such as retort treatment.

[0028] The reason why the excellent interlayer adhesion is maintained even after heat sterilization among the above-mentioned effects is not yet clear, but is considered to be as described below.

[0029] That is, by making the peak intensity ratio A of the second substrate layer be more than 0.75, the crystallinity of the second substrate layer is reduced, and sufficient flexibility can be given to the second substrate layer. Therefore, even when the laminate is greatly deformed by heat sterilization and the first substrate layer is greatly deformed therewith, the second substrate layer can easily follow the deformation of the first substrate layer through its sufficient flexibility. Therefore, the shear stress between the second substrate layer and the first substrate layer can be reduced. In addition, by reducing the shear stress between the second substrate layer and the first substrate layer, the deformation generated in the first substrate layer is reduced, and the shear stress between the first substrate layer and the sealant layer can also be reduced. The result is that the laminate can have excellent interlayer adhesion even after the heat sterilization of the laminate.

[0030] In the laminate, the second base layer may be an unstretched film, and the first base layer may be a stretched film.

[0031] The laminate may further include the inorganic oxide layer and a gas barrier layer between at least one of the first base layer and the second base layer and between the first base layer and the sealant layer.

[0032] In this case, the gas barrier properties of the gas barrier layered product can be further improved.

[0033] The laminate may further include the inorganic oxide layer and the gas barrier layer between the first base layer and the second base layer.

[0034] In this case, the laminate can have more excellent interlayer adhesion even after heat sterilization, compared to the case where an inorganic oxide layer and a gas barrier layer are provided between the first base material layer and the sealant layer.

[0035] In the laminated body, the inorganic oxide layer may be a vapor-deposited layer, and the vapor-deposited layer may include at least one of aluminum oxide and silicon oxide.

[0036] In this case, the laminate can improve various sterilization resistances.

[0037] In the above-mentioned laminate, the gas barrier layer may be a layer formed of a coating liquid containing a silicon compound and a water-soluble polymer, the silicon compound may contain at least one of a first silicon compound and a second silicon compound, the first silicon compound may contain at least one of a silicon alkoxide represented by the following general formula (1) and a hydrolyzate thereof, and the second silicon compound may contain at least one of a silane coupling agent represented by the following general formula (2) and a hydrolyzate thereof.

[0038] (In the above general formula (1), OR 1 represents a hydrolyzable group.) (In the above general formula (2), OR 3 Represents a hydrolyzable group, R 2 represents a monovalent organic group. n is an integer greater than or equal to 1. In this case, the interlayer adhesion of the laminate can be further improved.

[0039] In the above-mentioned laminate, the oxygen permeability at 30°C and 70 RH% can be 200 cc / m 2 ·day·atm or less.

[0040] According to the laminate, the oxygen permeability at 30°C and 70 RH% exceeds 200 cc / m 2 When a packaging container is manufactured using the stacked body 100 and contents are stored in the packaging container to manufacture a packaged product, the degradation of the contents due to oxygen can be effectively suppressed, compared with the case of ·day·atm.

[0041] In the laminate, the anchor coating layer may include an organic polymer, and the organic polymer may include at least one of a polyacrylic resin, a polyol resin, a polyurethane resin, a polyamide resin, and a reaction product of these resins.

[0042] The thickness of the anchor coating layer may be 0.01-1 μm.

[0043] In this case, compared to a case where the anchor coating layer has a thickness of less than 0.01 μm, the surface smoothness of the anchor coating layer can be further improved compared to the surface of the first substrate layer, the thickness of the deposited layer can be made more uniform, and the oxygen barrier properties can be further enhanced. Consequently, the oxygen barrier properties of the laminate can be further enhanced. Furthermore, compared to a case where the anchor coating layer has a thickness exceeding 1 μm, the flexibility of the laminate can be further enhanced, further improving the oxygen barrier properties of the laminate after harsh treatment.

[0044] Yet another aspect of the present disclosure provides a packaging container formed using the above-mentioned laminate.

[0045] According to the packaging container, the barrier film has excellent lamination strength with the sealant layer serving as another film even after heat sterilization, and the laminate has excellent interlayer adhesion even after heat sterilization, thereby suppressing the occurrence of interlayer delamination even after heat sterilization.

[0046] Furthermore, a packaging container using the aforementioned laminate comprises, in this order, a second substrate layer, a barrier film, and a sealant layer, wherein the barrier film's substrate layer is the first substrate layer, and the second substrate layer, the first substrate layer, and the sealant layer all comprise polypropylene film. When the peak intensity ratio A is 0.75 or greater, the laminate exhibits excellent recyclability and maintains superior interlayer adhesion even after heat sterilization. Therefore, even after heat sterilization of a packaged product containing contents within the packaging container, delamination in the laminate can be further suppressed. Furthermore, after the contents are removed from the packaged product, the packaging container exhibits excellent recyclability.

[0047] Yet another aspect of the present disclosure provides a packaged product comprising a packaging container and contents housed in the packaging container, wherein the packaging container is the aforementioned packaging container.

[0048] Depending on the packaging product, the barrier film has excellent lamination strength with the sealant layer as another film even after heat sterilization, and thus can suppress the occurrence of interlayer delamination even after heat sterilization.

[0049] Furthermore, when a packaging product comprises a packaging container obtained using the above-described laminate, the laminate comprising, in this order, a second substrate layer, a barrier film, and a sealant layer, the barrier film's substrate layer being the first substrate layer, and the second substrate layer, the first substrate layer, and the sealant layer all comprising a polypropylene film, and the peak intensity ratio A being 0.75 or greater, the laminate exhibits excellent recyclability and can exhibit even superior interlayer adhesion even after heat sterilization. Therefore, delamination in the gas-barrier laminate can be suppressed even after heat sterilization. Furthermore, the packaging container remaining after the contents are removed from the packaged product exhibits excellent recyclability.

[0050] Effects of the Invention According to the present disclosure, it is possible to provide a barrier film, a laminate, a packaging container, and a packaging product that have excellent lamination strength with other films even after heat sterilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a schematic cross-sectional view showing one embodiment of the barrier film disclosed herein.

[0052] Figure 2This is a schematic cross-sectional view showing a first embodiment of the laminated body of the present disclosure.

[0053] Figure 3 This is a schematic cross-sectional view showing a second embodiment of the laminated body of the present disclosure.

[0054] Figure 4 2 is a schematic cross-sectional view showing a first embodiment of the packaged product of the present disclosure.

[0055] Figure 5 It is a schematic cross-sectional view showing a third embodiment of the laminated body of the present disclosure.

[0056] Figure 6 This is a schematic cross-sectional view showing a fourth embodiment of the laminated body of the present disclosure.

[0057] Figure 7 2 is a schematic cross-sectional view showing a second embodiment of the packaged product of the present disclosure. DETAILED DESCRIPTION

[0058] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as needed. However, the present disclosure is not limited to the following embodiments.

[0059] <Barrier Film> First, refer to Figure 1 One embodiment of the barrier film disclosed herein will be described. Figure 1 : is a schematic cross-sectional view showing one embodiment of a barrier film as one aspect of the present disclosure. Figure 1 As shown, the barrier film 10 of the present embodiment includes a base layer 1 made of a polypropylene resin, an anchor coating layer 2 , an inorganic oxide layer 3 , and a gas barrier layer 4 in this order.

[0060] like Figure 1 As shown, the substrate layer 1 may be composed of a multilayer film including a skin layer 11 and a core layer 12, or may be composed of only the skin layer 11. The skin layer 11 is a contact layer with the anchor coating layer 2.

[0061] In the barrier film 10 , when the softening temperatures of the anchor coating layer 2 and the skin layer 11 are measured by local thermal analysis (LTA), the softening temperature T1 of the skin layer 11 is lower than the softening temperature T2 of the anchor coating layer 2 .

[0062] The barrier film 10 has excellent lamination strength with other films even after another film such as a sealant layer is attached to the gas barrier layer 4 and then subjected to heat sterilization.

[0063] Hereinafter, the base material layer 1 , the anchor coating layer 2 , the inorganic oxide layer 3 , and the gas barrier layer 4 will be described in detail.

[0064] [Base material layer] The substrate layer 1 is a film (base film) serving as a support, and includes a skin layer 11 and a core layer 12 .

[0065] (core layer) The core layer 12 contains polypropylene resin.

[0066] Examples of the polypropylene resin include homopolypropylene resins which are propylene homopolymers, random copolymers of propylene and α-olefins, and mixtures thereof. Homopolypropylene resins which are propylene homopolymers are preferred from the viewpoint of improving heat resistance.

[0067] The polypropylene resin used in the core layer 12 may be a resin polymerized from fossil fuels, a recycled resin, or a resin polymerized from raw materials derived from plants or other biomass. These resins may be used alone, or a mixture of a resin polymerized from fossil fuels and a recycled resin or a resin polymerized from raw materials derived from plants or other biomass may be used.

[0068] The polypropylene resin may be an amorphous polypropylene resin or a crystalline polypropylene resin.

[0069] The content of the polypropylene resin may be 90% by mass or more, 95% by mass or more, or 99% by mass or more based on the total mass of the core layer 12. The content of the polypropylene resin may also be substantially 100% by mass based on the total mass of the core layer 12. In other words, the core layer 12 may be a layer consisting essentially only of polypropylene resin.

[0070] The core layer 12 may contain organic additives such as antioxidants, stabilizers, lubricants, and antistatic agents as needed, and may contain inorganic additives such as silica, zeolite, hydrotalcite, silicon particles, and Syloid.

[0071] The thickness (total thickness) of the core layer 12 is not particularly limited and may be, for example, 3 μm to 200 μm, 6 μm to 50 μm, or 10 μm to 30 μm. A core layer 12 thickness of 3 μm or greater reduces wrinkling during production of the barrier film 10 and during use as a packaging film, making handling easier. A core layer 12 thickness of 200 μm or less further improves handling during roll-to-roll processing.

[0072] (Cortex) The skin layer 11 included in the base material layer 1 is a contact layer that is in contact with the anchor coating layer 2 and is provided between the core layer 12 and the anchor coating layer 2 .

[0073] The skin layer 11 includes polypropylene resin.

[0074] As the polypropylene resin, a copolymer of propylene and other monomers can be used. As other monomers used in the copolymer, for example, α-olefins such as ethylene, 1-butene, and 1-hexene can be used.

[0075] When the other monomer is an α-olefin, the skin layer 11 contains a copolymer of propylene and the α-olefin. In this case, the difference between the softening temperature T1 of the skin layer 11 and the softening temperature T2 of the anchor coating layer 2 can be easily increased.

[0076] The copolymer may be a random copolymer.

[0077] The copolymer used in the skin layer 11 may be a resin polymerized from fossil fuels, a recycled resin, or a resin polymerized from raw materials derived from plants or other biomass. These resins may be used alone, or a mixture of a resin polymerized from fossil fuels and a recycled resin or a resin polymerized from raw materials derived from plants or other biomass may be used.

[0078] The content of propylene units in the copolymer may be 80 mol % or more, 90 mol % or more, 95 mol % or more, or 96 mol % or more, and may be 99.7 mol % or less, 99.5 mol % or less, 99 mol % or less, or 98 mol % or less, based on the total amount of monomer units.

[0079] The content of the polypropylene resin in the skin layer 11 may be 90% by mass or greater, 95% by mass or greater, or 99% by mass or greater, based on the total mass of the skin layer 11. The content of the polypropylene resin may also be substantially 100% by mass, based on the total mass of the skin layer 11. In other words, the skin layer 11 may be a layer consisting essentially only of polypropylene resin.

[0080] The skin layer 11 may contain organic additives such as antioxidants, stabilizers, lubricants, and antistatic agents as needed, and may contain inorganic additives such as silica, zeolite, hydrotalcite, silicon particles, and Syloid.

[0081] The softening temperature T1 of the skin layer 11 is lower than the softening temperature T2 of the anchor coating layer 2. Since the base layer 1 includes the skin layer 11, the barrier film 10 has excellent lamination strength with other films even after heat sterilization.

[0082] In the barrier film 10 , T2 - T1 is not particularly limited as long as it is greater than 0° C., but is preferably 70° C. or less.

[0083] When T2 - T1 is 70° C. or lower, the difference in flexibility between the skin layer 11 and the anchor coating layer 2 is unlikely to increase, and the adhesion between the skin layer 11 and the anchor coating layer 2 is unlikely to decrease.

[0084] T2-T1 is preferably 68°C or lower, more preferably 60°C or lower.

[0085] Furthermore, T2-T1 is preferably 1°C or higher, more preferably 2°C or higher. A T2-T1 of 3°C or higher enhances the flexibility imparted to the skin layer 11, thereby alleviating the stress applied to the anchor coating layer 2 and the inorganic oxide layer 3 due to the shrinkage of the substrate layer 1 after heat sterilization. In other words, the difference in deformation between the substrate layer 1 and the anchor coating layer 2 can be effectively compensated. Consequently, damage to the inorganic oxide layer 3 can be suppressed, and degradation of the barrier properties of the inorganic oxide layer 3 can be prevented.

[0086] The softening temperature T1 of the skin layer 11 is not particularly limited as long as it is lower than the softening temperature T2 of the anchor coating layer 2, but is preferably between 115°C and 170°C. A softening temperature T1 of 115°C or higher prevents excessively low heat resistance of the skin layer 11, making it less susceptible to softening during heat sterilization. This reduces the likelihood of decreased adhesion to the anchor coating layer 2 or core layer 12, or deterioration in barrier properties. Furthermore, a softening temperature T1 of 170°C or lower suppresses a decrease in the flexibility of the skin layer 11, further enhancing the adhesion strength between the skin layer 11 and the core layer 12.

[0087] From the perspective of imparting heat resistance to the skin layer 11, the softening temperature T1 may be 120°C or higher, 125°C or higher, or 130°C or higher. From the perspective of imparting flexibility to the skin layer 11, the softening temperature T1 may be 165°C or lower or 160°C or lower.

[0088] The skin layer 11 may have only the softening temperature T1 or may have one or more softening temperatures higher than the softening temperature T1. When the skin layer 11 has multiple softening temperatures, the lowest softening temperature is the softening temperature T1.

[0089] The softening temperature T1 of the skin layer 11 may be lower than the softening temperature T3 of the core layer 12, or may be higher than the softening temperature T3 of the core layer 12. When the softening temperature T1 of the skin layer 11 is lower than the softening temperature T3 of the core layer 12, the stress transmitted from the core layer 12 to the anchor coating layer 2 tends to increase. Therefore, it is particularly useful to set the softening temperature T1 of the skin layer 11 lower than the softening temperature T2 of the anchor coating layer 2. In this case, T3 - T1 may be higher than 20°C or higher than 25°C. T3 - T1 may be lower than 80°C or lower than 75°C.

[0090] The thickness (total thickness) of the skin layer 11 is not particularly limited, and may be, for example, 0.1 μm to 5 μm, 0.2 μm to 3 μm, or 0.3 μm to 2 μm.

[0091] The base layer 1 can be formed by, for example, coextruding a resin forming the core layer 12 and a resin forming the skin layer 11 into a sheet, and then stretching the sheet to achieve uniaxial or biaxial orientation as needed. The skin layer 11 can be formed on only one side of the core layer 12 or on both sides.

[0092] [Anchor coating] The anchor coating layer 2 is a layer for further improving the adhesion between the base material layer 1 and the inorganic oxide layer 3 , and is provided between the base material layer 1 and the inorganic oxide layer 3 .

[0093] The material constituting the anchor coating layer 2 is not particularly limited as long as it can improve the adhesion between the substrate layer 1 and the inorganic oxide layer 3. For example, a material comprising a reaction product of a polyol compound containing a (meth)acrylic resin and an isocyanate compound can be used. In the following description, "(meth)acrylic resin" refers to at least one of an "acrylic resin" and its corresponding "methacrylic resin."

[0094] Examples of (meth)acrylic resins include (meth)acrylic polymers obtained by polymerizing polymerizable monomers including (meth)acrylic monomers. (Meth)acrylic polymers may be homopolymers of (meth)acrylic monomers or copolymers of (meth)acrylic monomers and polymerizable monomers other than (meth)acrylic monomers. (Meth)acrylic resins may also be resins capable of thermal crosslinking, such as by urethane curing or epoxy curing. From the perspective of reactivity with isocyanate compounds used as curing agents, as described below, the (meth)acrylic resin may be a polyol having two or more hydroxyl groups per molecule, particularly a (meth)acrylic polyol.

[0095] The (meth)acrylic polyol may be a (meth)acrylic copolymer obtained by copolymerizing a hydrocarbon (meth)acrylate with a hydroxyl-containing monomer, or a (meth)acrylic copolymer obtained by copolymerizing a hydrocarbon (meth)acrylate with a hydroxyl-containing monomer and other monomer components (other monomer components). By copolymerizing the above-mentioned hydroxyl-containing monomer with at least one of the hydrocarbon (meth)acrylate and other monomer components, a (meth)acrylic polyol containing multiple hydroxyl groups can be obtained.

[0096] The anchor coating layer 2 may contain a curing agent. From the viewpoint of excellent reactivity with a (meth)acrylic resin, the curing agent may be an isocyanate compound having two or more NCO groups in the molecule.

[0097] The isocyanate compound may be a monomeric isocyanate. Examples of monomeric isocyanates include aromatic isocyanates or aromatic aliphatic isocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylene diisocyanate (XDI), and tetramethylxylene diisocyanate (TMXDI); and aliphatic isocyanates such as hexamethylene diisocyanate (HDI), diisocyanatomethylcyclohexane (H6XDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane diisocyanate (H12MDI).

[0098] The isocyanate compound may also be a polymer or derivative of the aforementioned monomeric isocyanates. Examples of the isocyanate compound include a trimer-type urate-type isocyanate, an adduct-type isocyanate formed by reaction with 1,1,1-trimethylolpropane, or a biuret-type isocyanate formed by reaction with biuret. Due to its excellent reactivity with (meth)acrylic resins, the isocyanate compound may be an isocyanate having an aromatic ring.

[0099] When the (meth)acrylic resin is a (meth)acrylic polyol, the content of the isocyanate compound may be such that the number of OH groups of the acrylic polyol and the number of NCO groups of the isocyanate compound are equal.

[0100] To further enhance adhesion to the inorganic oxide layer 3, the anchor coating layer 2 may further contain a silane coupling agent. Examples of the silane coupling agent include epoxy-based silane coupling agents having an epoxy group, such as 3-glycidoxypropyltrimethoxysilane; amino-based silane coupling agents having an amino group, such as 3-aminopropyltrimethoxysilane; mercapto-based silane coupling agents having a mercapto group, such as 3-mercaptopropyltrimethoxysilane; and isocyanate-based silane coupling agents having an NCO group, such as 3-isocyanatepropyltriethoxysilane. These silane coupling agents may be used alone or in combination of two or more.

[0101] Other materials constituting the anchor coating 2 may also include polyurethane resin. If the material constituting the anchor coating 2 includes polyurethane resin, the barrier film 10 can have high heat resistance and high durability against heat sterilization. For example, the polyurethane resin can be formed from an acid-containing polyurethane and a polyamine. The polyurethane resin is obtained by bonding the acid groups of the acid-containing polyurethane to the amino groups of a polyamine serving as a crosslinking agent. In other words, the polyurethane resin can be said to be a reaction product of an acid-containing polyurethane and a polyamine, or a product of the acid-containing polyurethane crosslinked by a polyamine. The bond between the acid groups of the acid-containing polyurethane and the amino groups of the polyamine can be an ionic bond (e.g., an ionic bond between a carboxyl group and a tertiary amino group) or a covalent bond (e.g., an amide bond).

[0102] In addition, a silane coupling agent or a carbodiimide compound may be added to the polyurethane resin. By adding a silane coupling agent or a carbodiimide compound, a cross-linked structure is formed with the polyurethane resin, which can further improve the adhesion between the substrate layer 1 and the inorganic oxide layer 3. As the silane coupling agent, commonly used silane coupling agents can be used, for example, compounds having an alkoxy group and an organic reactive group bonded to a silicon atom.

[0103] The thickness of the anchor coating layer 2 is not particularly limited as long as it improves the adhesion between the substrate layer 1 and the inorganic oxide layer 3, but is preferably 30 nm or greater. In this case, compared to a case where the thickness of the anchor coating layer 2 is less than 30 nm, the surface smoothness of the anchor coating layer 2 can be further improved, the thickness of the inorganic oxide layer 3 can be made more uniform, and the oxygen barrier properties can be further improved. Therefore, the oxygen barrier properties of the barrier film 10 can be further improved. The thickness of the anchor coating layer 2 is more preferably 40 nm or greater, and even more preferably 50 nm or greater. By increasing the thickness of the anchor coating layer 2, the reduction in water vapor barrier properties when external forces such as stretching are applied can be further suppressed.

[0104] The thickness of the anchor coating layer 2 is preferably 2000 nm (2 μm) or less. This further enhances the flexibility of the barrier film 10 compared to a thickness exceeding 2000 nm, further improving the oxygen barrier properties of the barrier film 10 after harsh treatment. The thickness of the anchor coating layer 2 is more preferably 1500 nm (1.5 μm) or less.

[0105] The thickness of the anchor coating layer 2 is preferably 50 nm (0.05 μm) or more and 2000 nm (2 μm) or less. This further reduces the degradation of the water vapor barrier properties when external forces such as stretching are applied to the barrier film 10. Furthermore, the flexibility of the barrier film 10 is further enhanced, further improving the oxygen barrier properties of the barrier film 10 after harsh treatment.

[0106] The anchor coating layer 2 can be formed, for example, by applying an anchor coating solution on the skin layer 11 of the base material layer 1 by a method such as gravure coating, roll coating, or bar coating, and drying the solution.

[0107] The softening temperature T2 of the anchor coating layer 2 only needs to be higher than the softening temperature T1 of the skin layer 11 , and is preferably within the range of 140° C. to 195° C.

[0108] A softening temperature T2 of 140°C or higher improves the heat resistance of the anchor coating layer 2. Even at high temperatures during heat sterilization, such as retorting, deformation of the anchor coating layer 2 is minimized, reducing damage to the inorganic oxide layer 3. Consequently, the barrier film 10 can further improve its oxygen permeability even after heat sterilization.

[0109] The softening temperature T2 is preferably 142°C or higher, more preferably 145°C or higher, and particularly preferably 150°C or higher.

[0110] Furthermore, by setting the softening temperature T2 of the anchor coating layer 2 to 195° C. or lower, the anchor coating layer 2 does not become too hard, easily achieving durability against deformation of the barrier film 10 during heat sterilization such as retorting, and the inorganic oxide layer 3 is less likely to be destroyed.

[0111] The softening temperature T2 of the anchor coating layer 2 is more preferably 192° C. or lower, and further preferably 190° C. or lower.

[0112] Furthermore, the anchor coating layer 2 may have only the softening temperature T2 or may have one or more softening temperatures higher than the softening temperature T2. When the anchor coating layer 2 has multiple softening temperatures, the lowest softening temperature is the softening temperature T2.

[0113] The softening temperature T2 of the anchor coating layer 2 can be adjusted by changing the mixing ratio of the components in the anchor coating layer-forming composition or adjusting the coating conditions (drying temperature, etc.) when applying the anchor coating layer-forming composition.

[0114] [Inorganic oxide layer] The inorganic oxide layer 3 contains an inorganic oxide. The inorganic oxide layer 3 may or may not be formed directly on the anchor coating layer 2. However, from the perspective of improving the gas barrier properties against water vapor, oxygen, etc., it is preferably formed directly on the anchor coating layer 2. The inorganic oxide layer 3 may or may not be transparent.

[0115] As the inorganic oxide, for example, aluminum oxide, silicon oxide, tin oxide, magnesium oxide, or a mixture thereof can be used. From the viewpoint of excellent sterilization resistance, the inorganic oxide may be at least one selected from aluminum oxide and silicon oxide.

[0116] From the perspective of achieving uniform film thickness and excellent gas barrier properties, the thickness of the inorganic oxide layer 3 may be 5 nm or more, 10 nm or more, or 15 nm or more. From the perspective of preventing cracks from occurring in the inorganic oxide layer 3 even when external force is applied after film formation, the thickness may be 300 nm or less, 150 nm or less, or 100 nm or less. From these perspectives, the thickness of the inorganic oxide layer 3 may be 5 to 300 nm, 10 to 150 nm, or 15 to 100 nm.

[0117] The inorganic oxide layer 3 can be formed, for example, by vacuum deposition, plasma-assisted deposition, ion beam-assisted deposition, sputtering, reactive deposition, etc. From the perspective of excellent productivity, the inorganic oxide layer 3 can be formed by vacuum deposition. From the perspective of excellent adhesion between the inorganic oxide layer 3 and the anchor coating layer 2 and improved density of the inorganic oxide layer 3, the inorganic oxide layer 3 can be formed by plasma-assisted deposition or ion beam-assisted deposition. From the perspective of excellent transparency of the inorganic oxide layer 3, the inorganic oxide layer 3 can be formed by reactive deposition by blowing various gases such as oxygen.

[0118] Examples of heating methods for vacuum deposition include electron beam heating, resistance heating, and induction heating. Electron beam heating is preferred because it offers a wide range of selectivity for evaporation materials.

[0119] [Gas barrier layer] The gas barrier layer 4 is provided on the side of the inorganic oxide layer 3 opposite to the anchor coating layer 2. The barrier film 10 including the gas barrier layer 4 can protect the inorganic oxide layer 3 and further improve the gas barrier properties of the barrier film 10. The barrier film 10 does not necessarily need to include the gas barrier layer 4.

[0120] The gas barrier layer 4 may contain a silicon compound or a hydrolyzate thereof, and a water-soluble polymer having a hydroxyl group.

[0121] As the silicon compound, for example, it can be selected from Si(OR 1 ) 4 and R 2 Si (OR 3 ) At least one of the following 3. OR 1 and OR 3 are each independently a hydrolyzable group, R 2 is an organic functional group. 2 , vinyl, epoxy, methacryloyloxy, urea, isocyanate, etc. can be mentioned. From the perspective of being relatively stable in aqueous solvents after hydrolysis, Si (OR 1 )4 can be tetraethoxysilane (Si(OC2H5)4).

[0122] Examples of the water-soluble polymer having a hydroxyl group include polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, etc. From the viewpoint of excellent gas barrier properties, the water-soluble polymer having a hydroxyl group may be polyvinyl alcohol.

[0123] The gas barrier layer 4 may further contain additives such as an isocyanate compound, a silane coupling agent, a dispersant, a stabilizer, a viscosity modifier, and a colorant as needed.

[0124] The thickness of the gas barrier layer 4 may be 0.1 μm or 0.3 μm or more, and 5 μm or 1 μm or less. The thickness of the gas barrier layer 4 may be 0.1 to 5 μm or 0.3 to 1 μm.

[0125] When the thickness of the gas barrier layer 4 is 0.1 μm or greater, the barrier properties after retorting are less likely to deteriorate. When the thickness of the gas barrier layer 4 is 5 μm or less, degradation of the gas barrier layer 4 due to insufficient drying during coating is less likely to occur, and thus good barrier properties are more likely to be exhibited. When the thickness of the gas barrier layer 4 is 1 μm or less, degradation of the gas barrier layer 4 due to insufficient drying during coating is even less likely to occur, and thus even better barrier properties are more likely to be exhibited.

[0126] The gas barrier layer 4 can be formed, for example, by dissolving a water-soluble polymer in water or a water / alcohol mixed solvent, mixing the silicon compound or its hydrolyzate, applying the mixed solution on the inorganic oxide layer 3 by gravure coating, roll coating, bar coating, etc., and drying it.

[0127] When the water-soluble polymer is polyvinyl alcohol, the content of polyvinyl alcohol in the mixed solution may be 20% by mass or more, or 25% by mass or more, based on the total solids content of the mixed solution, from the perspective of facilitating formation of the gas barrier layer 4. From the perspective of achieving excellent gas barrier properties, the content of polyvinyl alcohol in the mixed solution may be 50% by mass or less, or 40% by mass or less. The content of polyvinyl alcohol in the mixed solution may be 20-50% by mass, or 25-40% by mass, based on the total solids content of the mixed solution.

[0128] [Softening temperature] The softening temperature is measured from a cross section of each layer of the barrier film 10 .

[0129] (Measurement sample) First, the barrier film 10 is prepared. In this case, the barrier film 10 itself may be prepared, or a laminated body in which another film such as a sealant layer is attached to the barrier film 10 may be prepared.

[0130] Next, the barrier film 10 is cut into rectangular or wedge-shaped pieces using a razor. The resulting cut pieces are then embedded with an embedding resin to form blocks. A photocurable resin is used as the embedding resin. For example, D-800 (trade name) manufactured by Toagosei Co., Ltd. can be used as a photocurable resin. Furthermore, to prevent separation between the embedding resin and the barrier film 10 after embedding, the barrier film 10 or the laminate may be subjected to a corona treatment on both sides as a surface treatment before cutting.

[0131] Next, the block is irradiated with light to cure the embedding resin to form the embedding resin.

[0132] Next, the cured piece was fixed with an insert in an AFM specimen holder. The embedding resin was trimmed with a glass cutter at room temperature (25°C), and a cross-section of the barrier film 10 was cut using a cross-section cutting device. Finally, the cross-section was cut using a diamond knife at low temperature (-40°C) using the cross-section cutting device until a mirror surface was achieved, thereby obtaining a measurement sample with the cross section of the barrier film 10 exposed.

[0133] Cross-section cutting with a diamond knife can be performed, for example, at a cutting speed of 1.0 mm / s and a cutting film thickness of 100 nm. The measurement sample was fixed with an AFM sample holder insert for use in measuring the softening temperature.

[0134] As the cross-section cutting apparatus, for example, an ultramicrotome EM UC7 (trade name) or a CryoSystem EM FC7 (trade name) manufactured by Leica Inc. can be used. The cutting direction is parallel to the interface with the adjacent layer.

[0135] (Softening temperature measurement method) The softening temperature refers to the temperature at which a substance such as a resin exhibits softening behavior. The softening temperature in this embodiment is measured by performing local thermal analysis (LTA) on a measurement sample using an atomic force microscope (AFM).

[0136] To determine the softening temperature, the sample is heated by applying a voltage to a cantilever equipped with a heater. After measuring the cross-sectional shape of the sample using local thermal analysis (LTA), a constant force (touch pressure) is applied to a specified location on the sample's cross-section using the cantilever. Heating is performed while maintaining a constant touch pressure. The temperature resulting from the change in cantilever height (Z displacement) caused by the change in sample surface hardness before and after heating is calculated as the softening temperature. The touch pressure is applied by the cantilever at the center of the thickness of the skin layer 11, anchor coating 2, and core layer 12. The change in cantilever height refers to the vertical positional rise of the cantilever due to thermal expansion of the sample surface and the vertical positional fall of the cantilever due to softening of the sample surface. By converting the applied voltage of the cantilever heater to the softening temperature when this change in cantilever height occurs, the softening temperature of the local nanoscale region near the surface can be determined.

[0137] The softening temperature was measured using an atomic force microscope (AFM) MFP-3D-SA (trade name) manufactured by Oxford Instruments and the Ztherm System (trade name) as a local thermal analysis option. The surface shape was measured using the AC mode (tapping mode), while the softening temperature was measured using the contact mode.

[0138] As the cantilever, AN2-200 (trade name) manufactured by Anasys Instruments, with a spring constant of 0.5 to 3.5 N / m, was used.

[0139] The voltage application rate (temperature increase rate) of the cantilever in the measurement of the softening temperature was 0.5 V / sec.

[0140] In the Ztherm System, the touch pressure of the cantilever is controlled to be constant. The so-called touch pressure refers to the force equivalent to the change in the deflection (Deflection) of the cantilever before and after the cantilever contacts the sample. Deflection is obtained by detecting the reflected light of the laser irradiated on the back of the cantilever using a laser displacement meter, and is thus obtained as a unit of voltage (hereinafter also referred to as "Deflection voltage"). The Deflection voltage changes according to the applied voltage during heating even if it is not in contact with the sample, so it is necessary to control the touch pressure on the basis of subtracting the change in the Deflection voltage caused by the applied voltage. The Ztherm System has a Detrend correction function for obtaining the change in the Deflection voltage relative to the applied voltage. The Ztherm System applies the applied voltage for measurement to the cantilever when the cantilever is not in contact with the sample surface, increases it from 0V to the maximum applied voltage, and performs Detrend correction on the applied voltage. In this embodiment, the shape of the surface is measured, and the applied voltage used for measurement before the softening temperature is measured is subjected to Detrend correction at a voltage application rate (heating rate) of 0.5V / second before measurement. When setting the touch pressure, the change in deflection voltage is set to 0.2 V, for example, when measuring the softening temperature T1 of the skin layer 11 of the substrate layer 1, 0.2 V when measuring the softening temperature T3 of the core layer 12 of the substrate layer 1, and 1.5 V when measuring the softening temperature T2 of the anchor coating layer 2.

[0141] The set value of the cantilever downward displacement for stopping the measurement is 10 nm.

[0142] The softening point is the point where the cantilever's vertical height (Z displacement) is maximum, and the applied voltage at this point is read.

[0143] In order to convert the applied voltage to the cantilever heater into the softening temperature, a calibration curve of applied voltage and temperature is prepared. As calibration samples, four polymer materials with melting points that differ by at least 50°C are used. As these polymer materials, materials with melting points above the softening temperature of the measurement sample and materials with melting points below the softening temperature are used. The melting point (melting peak temperature) of the calibration sample is measured in advance using a differential scanning calorimeter (DSC), and the melting point is used as the softening temperature of the calibration sample. Local thermal analysis is performed by changing the measurement position in each calibration sample. The average value of the applied voltage at the softening point obtained and the softening temperature of the calibration sample (melting point measured by DSC) are approximated with a cubic function using the least squares method to create a standard curve as the calibration curve. Calibration samples used were polycaprolactone pellets (melting point: 60°C), low-density polyethylene pellets (melting point: 112°C), polypropylene pellets (melting point: 166°C), and biaxially stretched polyethylene terephthalate film (melting point: 255°C). Cross-section specimens were prepared below the glass transition temperature. Cross-sections were prepared using an ultramicrotome and a CryoSystem at -80°C for polycaprolactone, -140°C for low-density polyethylene, -40°C for polypropylene, and room temperature (25°C) for polyethylene terephthalate.

[0144] The temperature corresponding to the applied voltage at the softening point is determined using the calibration curve of the applied voltage and temperature, and this temperature is defined as the softening temperature.

[0145] <Laminate> Next, refer to Figure 2 or Figure 3 A laminated body as another aspect of the present disclosure will be described. Figure 2 is a schematic cross-sectional view showing a first embodiment of a laminate according to another aspect of the present disclosure, Figure 3 : is a schematic cross-sectional view showing a second embodiment of a laminate according to another aspect of the present disclosure. Figure 2 as well as Figure 3 In, with Figure 1 The same or equivalent components are denoted by the same reference numerals.

[0146] like Figure 2 The laminated body of the present disclosure includes the barrier film 10 and the sealant layer 5 as another film, as shown in the laminated body 20. The laminated body of the present disclosure can be Figure 3 As shown in the laminate 30, it includes the barrier film 10, the sealant layer 5, and the second base layer 31 on the surface of the barrier film 10 opposite to the sealant layer 5. The second base layer 31 can contain, for example, a polyolefin resin.

[0147] According to the laminate 20 or 30 , the barrier film 10 has excellent adhesion with the sealant layer 5 even after heat sterilization, and thus the occurrence of interlayer delamination can be suppressed even after heat sterilization.

[0148] The sealant layer 5 only needs to contain a resin having heat sealability. Examples of such a resin include polyolefin resins and polyester resins.

[0149] Examples of the polyolefin resin include polyethylene resin and polypropylene resin. Of these, polypropylene resin is preferably used as the polyolefin resin from the viewpoint of improving recyclability.

[0150] As the polypropylene resin, the same polypropylene resin as that contained in the core layer 12 can be used.

[0151] The sealant layer 5 may be a stretched film or an unstretched film, but is preferably an unstretched film from the viewpoint of providing a lower melting point than the base material layer 1 .

[0152] The thickness of the sealant layer 5 can be 10 μm or more, or 20 μm or more, and 200 μm or less, or 100 μm or less. The thickness of the sealant layer 5 can be between 10 and 200 μm, or between 20 and 100 μm. When the sealant layer 5 has a thickness of 10 μm or more, packaging containers such as packaging bags are less susceptible to damage. When the sealant layer 5 has a thickness of 200 μm or less, the sealant layer 5 maintains heat-sealing properties, further reducing the likelihood of sealing defects.

[0153] The laminate 20 may include an adhesive layer (not shown) between the barrier film 10 and the sealant layer 5. The adhesive layer may be formed of, for example, a polyurethane resin obtained by reacting a difunctional or higher functional isocyanate compound with polyester polyol, polyether polyol, acrylic polyol, carbonate polyol, or the like.

[0154] From the viewpoint of improving adhesiveness, the adhesive layer may contain a carbodiimide compound, an oxazoline compound, an epoxy compound, a phosphorus compound, a silane coupling agent, and the like in addition to the polyurethane resin.

[0155] When the second base material layer 31 includes a polyolefin resin, examples of the polyolefin resin include polyethylene resin and polypropylene resin. From the viewpoint of increasing the rigidity of the laminate 30, the polyolefin resin is preferably a polypropylene resin.

[0156] As the polypropylene resin, the same polypropylene resin as that contained in the core layer 12 can be used.

[0157] In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the second base material layer 31, the intensity I of the (110) plane peak is 110 The intensity of the peak relative to the (040) plane is I040 The ratio, that is, the peak intensity ratio A, is 0.75 or more.

[0158] The laminate 20 has excellent recyclability and can maintain excellent interlayer adhesion even after heat sterilization such as retort treatment.

[0159] The peak intensity ratio A is preferably 0.80 or more, more preferably 0.90 or more.

[0160] The peak intensity ratio A may be 2 or less, 1.5 or less, 1.3 or less, or 1.1 or less.

[0161] <Packaging Products> Next, refer to Figure 4 A packaging product as yet another aspect of the present disclosure will be described. Figure 4 1 is a schematic cross-sectional view showing an embodiment of a packaging product according to another aspect of the present disclosure. Figure 1 or Figure 2 The same or equivalent components are denoted by the same reference numerals.

[0162] Figure 4 The packaged product 100 shown includes a packaging bag 40 as a packaging container and content C accommodated in the packaging bag 40 . The packaging bag 40 is formed using two laminated bodies 20 .

[0163] According to the packaged product 100 , the barrier film 10 has excellent adhesion to the sealant layer 5 even after heat sterilization, and thus the occurrence of interlayer delamination can be suppressed even after heat sterilization.

[0164] The content C is not particularly limited, and examples of the content C include food, liquids, pharmaceuticals, and electronic components.

[0165] The packaged product 100 can be formed by: Figure 4 In the process, two laminates 20 are overlapped with the sealant layers 5 facing each other, and a portion of the peripheral portion is heat-sealed to form a packaging bag 40. After the content C is placed in the remaining portion of the non-heat-sealed peripheral portion of the packaging bag 40, the remaining portion of the non-heat-sealed peripheral portion is heat-sealed.

[0166] Alternatively, the packaged product 100 may be formed using a single laminate 20. In this case, the packaged product 100 may be formed by folding the single laminate 20 in half, heat-sealing a portion of the peripheral portion other than the folded portion to form a packaging bag, placing the contents C in the remaining portion of the packaging bag that is not heat-sealed, and then heat-sealing the remaining portion of the peripheral portion that is not heat-sealed.

[0167] The packaged product 100 may further include a spout on the packaging bag 40. The spout can be secured by sandwiching it between the two laminated bodies 20 or 30 that form the packaging bag 40. Alternatively, a spout can be bonded to a hole in one surface of the packaging bag 40 and secured to the spout. The spout can be located anywhere on the upper side or diagonally above the packaging bag 40. If the packaging bag 40 has a top surface, a bottom surface, and side surfaces connecting them, the surface to which the spout is bonded can be any of the top, side, or bottom surfaces of the packaging bag 40.

[0168] If the contents C are liquid or gel, the spout can be a spout (so-called a nozzle) to allow direct oral suction. In this case, the packaged product 100 can include, in addition to the spout, a straw extending from the spout to the bottom of the packaging bag 40.

[0169] If the contents C in the packaging bag 40 are liquids such as soft drinks or alcoholic beverages, the packaged product may be a bag-in-box product further comprising a carton (outer box) housing the bag (inner bag) serving as the packaging bag. In this case, the packaged product may further comprise a spout (tube) provided on the outside of the carton, penetrating the carton and connected to the bag.

[0170] From the viewpoint of improving recyclability, the port plug may be formed of the same resin as that of the base material layer 1 of the barrier film 10 .

[0171] <Laminate> First, refer to Figure 5 A third embodiment of the laminated body of the present disclosure will be described. Figure 5 This is a schematic cross-sectional view showing a third embodiment of the laminated body of the present disclosure.

[0172] Figure 5 The laminate 100A shown includes a second base layer 10A, a first structure (hereinafter also referred to as a “barrier film”) 25 including a first base layer 20A, and a sealant layer 30A in this order.

[0173] The second base material layer 10A, the first base material layer 20A, and the sealant layer 30A all include polypropylene films.

[0174] In addition, in the X-ray diffraction pattern obtained by X-ray diffraction (XRD) measurement of the second base material layer 10A, the intensity I 110 The intensity of the peak relative to the (040) plane is I 040 The ratio of the peak intensity ratio A (=I 110 / I 040 ) is 0.75 or above.

[0175] Furthermore, the second base material layer 10A and the barrier film 25 may be bonded together via the adhesive layer 40A, and the sealant layer 30A and the barrier film 25 may be bonded together via the adhesive layer 40A.

[0176] The barrier film 25 includes an anchor coating layer 21 and a vapor-deposited layer 22 as an inorganic oxide layer, in this order from the first base layer 20A side, between the first base layer 20A and the second base layer 10A. The barrier film 25 may further include a gas barrier layer 23 on the vapor-deposited layer 22.

[0177] In the barrier film 25 , when the softening temperatures of the anchor coating layer 21 and the first base layer 20A are measured by local thermal analysis (LTA), the softening temperature T1 of the first base layer 20A is lower than the softening temperature T2 of the anchor coating layer 21 .

[0178] According to the laminate 100A, the barrier film 25 has excellent lamination strength with the sealant layer 30A even after the sealant layer 30A, which is another film, is bonded to the gas barrier layer 23 and then subjected to heat sterilization.

[0179] Furthermore, the laminate 100A has excellent recyclability and maintains excellent interlayer adhesion even after heat sterilization treatments such as retorting. In particular, the laminate 100A can improve the interlayer adhesion between the second substrate layer 10A and the first substrate layer 20A after heat sterilization. When the laminate 100A is used to manufacture packaging containers, the second substrate layer 10A becomes the outermost layer and is also the layer that is susceptible to external forces. Therefore, the laminate 100A, which can improve the interlayer adhesion between the second substrate layer 10A and the first substrate layer 20A after heat sterilization, is useful as a laminate for forming packaging containers.

[0180] Hereinafter, the second base material layer 10A, the barrier film 25 , the sealant layer 30A, and the adhesive layer 40A will be described in detail.

[0181] [Second base material layer] The second base material layer 10A includes a polypropylene film. The polypropylene film includes a polypropylene resin.

[0182] Examples of the polypropylene resin include homopolypropylene, which is a propylene homopolymer, and propylene-α-olefin copolymers, which are copolymers of propylene and α-olefin. These can be used alone or in combination of two or more.

[0183] The second base layer 10A may further include a layer containing a propylene-α-olefin copolymer or a mixture of a propylene-α-olefin copolymer and homopolypropylene on the surface of the polypropylene film in order to improve adhesion with a layer in contact with the second base layer 10A.

[0184] The polypropylene resin contained in the polypropylene film may be any of a fossil fuel-derived polypropylene resin obtained by homopolymerizing propylene derived from common fossil fuels or copolymerizing it with other monomers, a recycled polypropylene resin, or a biomass-derived polypropylene resin obtained by homopolymerizing propylene derived from biomass such as plants or copolymerizing it with other monomers. These polypropylene resins may be used alone or in combination of two or more.

[0185] The second base material layer 10A may further contain additives as needed. Examples of the additives include antioxidants, stabilizers, lubricants such as calcium stearate, fatty acid amide, and erucamide, organic additives such as antistatic agents, and particulate lubricants such as silica, zeolite, syloid, hydrotalcite, and silicon particles.

[0186] The polypropylene film contained in the second substrate layer 10A may be a stretched film or an unstretched film. The stretched film can be obtained by forming the above-mentioned polypropylene resin into a sheet and stretching the sheet using conventional means. The stretched film may be a uniaxially oriented film or a biaxially oriented film.

[0187] The polypropylene film is preferably an unstretched film. In this case, the laminate 100A can have more excellent interlayer adhesion even after heat sterilization.

[0188] The thickness of the second base layer 10A is not particularly limited, and may be, for example, 5 μm or more, 10 μm or more, or 15 μm or more. The thickness of the first base layer 20A may be 100 μm or less, 80 μm or less, 60 μm or less, or 40 μm or less.

[0189] The thickness of the second base layer 10A may be greater than the thickness of the first base layer 20A, or may be less than or equal to the thickness of the first base layer 20A.

[0190] In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the second base material layer 10A, the intensity I of the (110) plane peak is 110 The intensity of the peak relative to the (040) plane is I 040 The ratio, that is, the peak intensity ratio A, is 0.75 or more.

[0191] The peak intensity ratio A is preferably 0.80 or more, more preferably 0.90 or more.

[0192] The peak intensity ratio A may be 2 or less, 1.5 or less, 1.3 or less, or 1.1 or less.

[0193] [Barrier film] The barrier film 25 includes an anchor coating layer 21, a vapor-deposited layer 22, and a gas barrier layer 23 between the first substrate layer 20A and the second substrate layer 10A. Thus, when the vapor-deposited layer 22 and the gas barrier layer 23 are provided between the second substrate layer 10A and the first substrate layer 20A, the laminate 100A can have better interlayer adhesion even after heat sterilization, compared to when the vapor-deposited layer 22 and the gas barrier layer 23 are provided between the first substrate layer 20A and the sealant layer 30A.

[0194] (1) Anchor coating The anchor coating layer 21 is a layer for further improving the adhesion between the first base material layer 20A and the vapor-deposited layer 22 , and is provided between the first base material layer 20A and the vapor-deposited layer 22 .

[0195] The material constituting the anchor coating layer 21 includes an organic polymer. The organic polymer may be at least one of polyacrylic resin, polyol resin, polyurethane resin, polyamide resin, or a reaction product of these resins.

[0196] The polyurethane resin may contain a reaction product of a polyol compound and an isocyanate compound. From the perspective of transparency, the polyol compound is preferably an acrylic polyol. The isocyanate compound mainly functions as a crosslinking agent or a curing agent.

[0197] The proportion of the organic polymer in the material constituting the anchor coating layer 21 may be 50% by mass or greater, or may be 60% by mass or greater, 70% by mass or greater, 80% by mass or greater, or 90% by mass or greater. When the proportion of the organic polymer is 50% by mass or greater, the heat resistance, water resistance, and flexibility of the barrier film 25 can be further improved.

[0198] The softening temperature T2 of the anchor coating layer 21 only needs to be higher than the softening temperature T1 of the first base material layer 20A, and is preferably within the range of 140° C. to 195° C.

[0199] A softening temperature T2 of 140°C or higher improves the heat resistance of the anchor coating layer 21. Even at high temperatures during heat sterilization, such as retorting, deformation of the anchor coating layer 21 is minimized, thereby reducing damage to the deposited layer 22. Consequently, the barrier film 25 can further improve its oxygen permeability even after heat sterilization.

[0200] The softening temperature T2 is preferably 142°C or higher, more preferably 145°C or higher, and particularly preferably 150°C or higher.

[0201] Furthermore, since the softening temperature T2 of the anchor coating layer 21 is 195° C. or lower, the anchor coating layer 21 does not become too hard, and is easily durable against deformation of the barrier film 25 during heat sterilization such as retorting, and the deposited layer 22 is less likely to be damaged.

[0202] The softening temperature T2 of the anchor coating layer 21 is more preferably 192° C. or lower, and further preferably 190° C. or lower.

[0203] The anchor coating layer 21 may have only the softening temperature T2 or may have one or more softening temperatures higher than the softening temperature T2. When the anchor coating layer 21 has multiple softening temperatures, the lowest softening temperature is the softening temperature T2.

[0204] The softening temperature T2 of the anchor coating layer 21 can be adjusted by changing the mixing ratio of the components in the anchor coating layer-forming composition or adjusting the coating conditions (drying temperature, etc.) when applying the anchor coating layer-forming composition.

[0205] The thickness of the anchor coating layer 21 is not particularly limited, as long as it improves the adhesion between the first base layer 20A and the deposited layer 22, and may be 0.01 μm or greater. In this case, compared to a case where the anchor coating layer 21 thickness is less than 0.01 μm, the surface of the anchor coating layer 21 can be made smoother than the surface of the first base layer 20A, the thickness of the deposited layer 22 can be made more uniform, and the oxygen barrier properties can be further improved. Consequently, the oxygen barrier properties of the laminate 100A can be further enhanced.

[0206] The thickness of the anchor coating layer 21 may be 0.03 μm or more, 0.04 μm or more, or 0.05 μm or more. By increasing the thickness of the anchor coating layer 21, it is possible to further suppress a decrease in water vapor barrier properties when an external force such as tension is applied.

[0207] The thickness of the anchor coating layer 21 may be 1 μm or less. In this case, the flexibility of the laminate 100A is further improved compared to when the thickness of the anchor coating layer 21 exceeds 1 μm, and the oxygen barrier properties of the laminate 100A after harsh treatment can be further improved.

[0208] The thickness of the anchor coating layer 21 may be 0.3 μm or less or 0.2 μm or less.

[0209] Alternatively, the anchor coating layer 2 may be used in place of the anchor coating layer 21 .

[0210] (2) Evaporation layer The vapor-deposited layer 22 is a layer obtained by vapor deposition, and can further improve the gas barrier properties of the laminate 100A. The vapor-deposited layer 22 may or may not be transparent.

[0211] The deposited layer 22 is an inorganic oxide layer and is formed of an inorganic oxide. Examples of the inorganic oxide include metal oxides. Examples of the metal include at least one selected from Si, Al, Mg, Sn, Ti, and In. Examples of such metal oxides include aluminum oxide (AlO x ), silicon oxide (SiO x ), tin oxide, and magnesium oxide. These can be used alone or in mixtures of two or more. Of these, aluminum oxide or silicon oxide is preferred from the perspective of various sterilization resistance. Silicon oxide is particularly preferred as an inorganic oxide. In this case, the laminate 100A can exhibit even better water vapor barrier properties.

[0212] The vapor deposition layer 22 may be composed of a single layer or a plurality of layers.

[0213] The thickness of the deposited layer 22 varies depending on the type of material used, but is generally preferably 5 to 300 nm, with the value being appropriately selected within this range. When the thickness of the deposited layer 22 is 5 nm or greater, the deposited layer 22 easily forms a uniform film, effectively exhibiting its gas barrier function. Furthermore, when the thickness of the deposited layer 22 is 300 nm or less, the deposited layer 22 easily maintains its flexibility, and cracks in the deposited layer 22 caused by external factors such as bending and stretching of the laminate 100A are easily suppressed.

[0214] The thickness of the vapor-deposited layer 22 is more preferably 10 to 150 nm.

[0215] Alternatively, the inorganic oxide layer 3 may be used instead of the vapor-deposited layer 22 .

[0216] (3) Gas barrier layer The gas barrier layer 23 is a layer having gas barrier properties and is obtained using a gas barrier layer-forming composition. The gas barrier layer-forming composition contains a water-soluble polymer and a silicon compound. The silicon compound contains at least one of a first silicon compound and a second silicon compound.

[0217] The first silicon compound includes at least one of a silicon alkoxide represented by the following general formula (1) and a hydrolyzate thereof.

[0218] The second silicon compound includes at least one of a silane coupling agent represented by the following general formula (2) and a hydrolyzate thereof.

[0219] (In the above general formula (1), OR 1 represents a hydrolyzable group.) (In the above general formula (2), OR 3 Represents a hydrolyzable group, R 2represents a monovalent organic group. n is an integer greater than or equal to 1. The water-soluble polymer has a hydroxyl group. Examples of the water-soluble polymer include polyvinyl alcohol resin, its modified form, and polyacrylic acid. These can be used alone or in combination of two or more. Among them, polyvinyl alcohol resin or its modified form is preferred as the water-soluble polymer. In this case, the composition for forming the gas barrier layer can impart better gas barrier properties to the laminate 100A by curing. In addition, even if the composition for forming the gas barrier layer is cured, it can impart better flexibility to the laminate 100A, and can also suppress the generation of cracks in the gas barrier layer 23 during processes such as lamination.

[0220] When the water-soluble polymer is composed of a polyvinyl alcohol resin or a modified form thereof, the saponification degree of the water-soluble polymer is not particularly limited. From the perspective of improving the gas barrier properties of the laminate 100A, it is preferably 95% or higher, and may be 100%. If the saponification degree of the water-soluble polymer is 95% or higher, the water resistance of the gas barrier layer 23 is improved, and even during heat sterilization treatments such as retorting, a decrease in the gas barrier properties of the laminate 100A can be suppressed.

[0221] The degree of polymerization of the water-soluble polymer is not particularly limited, but is preferably 300 or higher from the perspective of improving the gas barrier properties of the laminate 100A. The degree of polymerization of the water-soluble polymer is preferably 450 to 2400. When the degree of polymerization of the water-soluble polymer is 2400 or lower, the viscosity of the coating liquid (gas barrier layer-forming composition) does not become too high, making it easier to form a gas barrier layer 23 of uniform thickness.

[0222] The content of the water-soluble polymer is not particularly limited, but is preferably 25% by mass or greater, based on the combined mass of the water-soluble polymer and the silicon compound (100% by mass). In this case, curing further improves the gas barrier properties and interlayer adhesion of the laminate 100A, even after heat sterilization. Based on the combined mass of the water-soluble polymer and the silicon compound, the content of the water-soluble polymer is preferably 26% by mass or greater, more preferably 27% by mass or greater, and particularly preferably 40% by mass or greater.

[0223] The content of the water-soluble polymer is also not particularly limited. Based on the combined mass of the water-soluble polymer and the silicon compound (100 mass%), the content is preferably 60 mass% or less, more preferably 58 mass% or less, and particularly preferably 55 mass% or less. When the content of the water-soluble polymer is 60 mass% or less, the water resistance of the gas barrier layer 23 is improved, further enhancing the gas barrier properties and interlayer adhesion of the laminate 100A even after heat sterilization.

[0224] The first silicon compound is at least one of a silicon alkoxide and a hydrolyzate thereof. The silicon alkoxide is represented by the general formula (1) above. In this case, not only can the gas barrier properties of the laminate 100A be improved, but the adhesion between the gas barrier layer 23 and the vapor-deposited layer 22 can also be improved, thereby suppressing intralayer delamination (delamination) in the laminate 100A.

[0225] In the above general formula (1), OR 1 represents a hydrolyzable group. 1 Examples include alkyl groups and -C2H4OCH3. Examples of alkyl groups include methyl and ethyl groups. Of these, ethyl groups are preferred. In this case, the silicon alkoxide becomes tetraethoxysilane (TEOS), which, after hydrolysis, is relatively stable in aqueous solvents.

[0226] The content of the first silicon compound is not particularly limited. Based on the combined mass of the water-soluble polymer and the silicon compound (100 mass%), the content is preferably 40 mass% or greater, more preferably 42 mass% or greater, and particularly preferably 45 mass% or greater. In this case, the gas barrier properties and interlayer adhesion of the laminate 100A can be further improved even after heat sterilization, compared to a case where the content of the first silicon compound is less than 40 mass%.

[0227] When the combined mass of the water-soluble polymer and the silicon compound is taken as a reference (100 mass%), the content of the first silicon compound is preferably 75 mass% or less, more preferably 74 mass% or less, and particularly preferably 73 mass% or less. When the content of the first silicon compound is 75 mass% or less, the cured gas barrier layer 23 does not become excessively hard, which reduces the likelihood of cracking in the gas barrier layer 23 and reduces the likelihood of deterioration in gas barrier properties. Furthermore, even after heat sterilization, the gas barrier properties and interlayer adhesion of the laminate 100A can be further improved. Furthermore, the amount of hydrochloric acid required for hydrolysis can be reduced, preventing the amount of chlorine in the laminate 100A from becoming excessive, thereby improving the recyclability of the laminate 100A.

[0228] The second silicon compound is at least one of a silane coupling agent and a hydrolyzate thereof. The silane coupling agent is represented by the general formula (2). In this case, the adhesion between the gas barrier layer 23 and the vapor-deposited layer 22 can be improved, and the interlayer adhesion of the laminate 100A can be further improved.

[0229] In the above general formula (2), R 2 Represents a monovalent organic group, OR 3 represents a hydrolyzable group, and n represents an integer of 1 or greater.

[0230] As R 2The monovalent organic group shown includes a vinyl group, an epoxy group, a mercapto group, an amino group, or an isocyanate group. Among these, the monovalent organic group is preferably an isocyanate group. In this case, the gas barrier layer-forming composition can have even better hot water resistance upon curing, and can impart stronger lamination strength to the laminate 100A even after heat sterilization.

[0231] As R 3 , alkyl and -C2H4OCH3 can be mentioned. Examples of the alkyl group include methyl and ethyl. Among them, methyl is preferred. At this time, the hydrolysis of the silane coupling agent proceeds rapidly.

[0232] In addition, R 3 Can be used with R 2 In addition, when n is an integer greater than 2, R 3 They can be the same or different from each other.

[0233] n represents an integer greater than or equal to 1. When n is 1, the silane coupling agent represents a monomer. Conversely, when n is 2 or greater, the silane coupling agent represents a polymer. n is preferably 3. In this case, the hot water resistance of the gas barrier layer 23 can be further improved, and even after heat sterilization, stronger lamination strength can be imparted to the laminate 100A.

[0234] Examples of silane coupling agents include vinyl-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; epoxy-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylethyldiethoxysilane; mercapto-containing silane coupling agents such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane; amino-containing silane coupling agents such as 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; and isocyanate-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane and 1,3,5-tris(3-methoxysilylpropyl)isocyanurate. These silane coupling agents can be used alone or in combination of two or more.

[0235] Among the above silane coupling agents, the most preferred one is the one having the general formula (NCO-R 4 Si (OR 3 )3)3(where R 4 -(CH2) n-, n is 1 or greater). This 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate has hydrophobicity due to the polarity of the urate portion, and thus can impart high water resistance to the gas barrier layer 23.

[0236] The content of the second silicon compound is not particularly limited. Based on the combined mass of the water-soluble polymer and the silicon compound (100 mass%), it is preferably 3 mass% or greater, more preferably 5 mass% or greater, and particularly preferably 7 mass% or greater. In this case, curing can impart greater lamination strength to the laminate 100A even after heat sterilization, compared to a case where the second silicon compound content is less than 3 mass%.

[0237] When the total mass of the water-soluble polymer and the silicon compound is taken as a reference (100 mass%), the content of the second silicon compound is preferably 20 mass% or less, more preferably 15 mass% or less, and particularly preferably 12 mass% or less. In this case, compared to a case where the content of the second silicon compound exceeds 20 mass%, the content of the water-soluble polymer and the first silicon compound in the gas barrier layer 23 is relatively higher, thereby maintaining good gas barrier properties.

[0238] In addition, when calculating the content of the water-soluble polymer, the first silicon compound and the second silicon compound, the above-mentioned content is calculated by converting the mass of the first silicon compound into the mass of SiO2 and the mass of the second silicon compound into R 2 The results were carried out on the basis of the mass of Si(OH)3.

[0239] The gas barrier layer-forming composition may contain known additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity modifier, and a colorant as needed within a range that does not impair the gas barrier properties.

[0240] The thickness of the gas barrier layer 23 is not particularly limited, but is preferably 0.1 μm or greater. In this case, the gas barrier properties of the laminate 100A can be further improved even after heat sterilization compared to a case where the thickness of the gas barrier layer 23 is less than 0.1 μm. From the perspective of improving the gas barrier properties of the laminate 100A, the thickness of the gas barrier layer 23 is more preferably 0.15 μm or greater, and particularly preferably 0.17 μm or greater.

[0241] On the other hand, the thickness of the gas barrier layer 23 is preferably 1.0 μm or less. Compared to a case where the thickness of the gas barrier layer 23 exceeds 1.0 μm, the laminate 100A is less likely to curl, making it easier to use as a laminate to form a packaging container. To further improve the flexibility of the laminate 100A, the thickness of the gas barrier layer 23 is more preferably 0.7 μm or less, and particularly preferably 0.5 μm or less.

[0242] In addition, the gas barrier layer 4 may be used instead of the gas barrier layer 23 .

[0243] [First base material layer] The first base material layer 20A is a contact layer with the anchor coating layer 21 and includes a polypropylene film. The polypropylene film includes a polypropylene-based resin (hereinafter also referred to as "polypropylene resin").

[0244] Examples of the polypropylene resin include homopolypropylene and propylene-α-olefin copolymers, which can be used alone or in combination of two or more.

[0245] In order to improve adhesion with a layer in contact with the first base layer 20A, the first base layer 20A may further have a layer containing a propylene-α-olefin copolymer or a mixture of a propylene-α-olefin copolymer and homopolypropylene on the surface of the polypropylene film.

[0246] The polypropylene resin contained in the polypropylene film may be any of a polypropylene resin derived from fossil fuels, a recycled polypropylene resin, and a polypropylene resin derived from biomass. These polypropylene resins may be used alone or in combination of two or more.

[0247] The first base layer 20A may further contain additives as needed. Examples of the additives include antioxidants, stabilizers, lubricants such as calcium stearate, fatty acid amide, and erucamide, organic additives such as antistatic agents, and particulate lubricants such as silica, zeolite, syloid, hydrotalcite, and silicon particles.

[0248] The polypropylene film contained in the first substrate layer 20A may be a stretched film or an unstretched film. The stretched film can be obtained by forming the above-mentioned polypropylene resin into a sheet and stretching the sheet using conventional means. The stretched film may be a uniaxially oriented film or a biaxially oriented film.

[0249] From the viewpoint of imparting rigidity to the laminate 100A, the first base material layer 20A is preferably a stretched film.

[0250] In order to strengthen the adhesion between the first base material layer 20A and the anchor coating layer 21 , the surface of the first base material layer 20A may be subjected to a surface treatment such as plasma treatment or corona treatment.

[0251] The first base layer 20A may be the same as or different from the second base layer 10A.

[0252] In the X-ray diffraction pattern obtained by X-ray diffraction (XRD) measurement of the first base material layer 20A, the intensity I of the (110) plane peak is 110 The intensity of the peak relative to the (040) plane is I 040 The ratio of the peak intensity ratio A (=I 110 / I 040 ) is not particularly limited, and the peak intensity ratio A can be greater than 0.75 or less than 0.75.

[0253] When the peak intensity ratio A is less than 0.75, the peak intensity ratio A may be 0.6 or less, 0.55 or less, or 0.5 or less.

[0254] In addition, the peak intensity ratio A may be 0.2 or more, 0.3 or more, or 0.4 or more.

[0255] In the barrier film 25 , T2 - T1 is not particularly limited as long as it is greater than 0° C., but is preferably 70° C. or less.

[0256] When T2 - T1 is 70° C. or lower, the difference in flexibility between the first base layer 20A and the anchor coating layer 21 is unlikely to increase, and the adhesion between the first base layer 20A and the anchor coating layer 21 is unlikely to decrease.

[0257] T2-T1 is preferably 68°C or lower, more preferably 60°C or lower.

[0258] Furthermore, T2-T1 is preferably 1°C or higher, more preferably 2°C or higher. A T2-T1 of 3°C or higher enhances the flexibility of the first base layer 20A, thereby alleviating the stress applied to the anchor coating layer 21 and the deposited layer 22 due to the shrinkage of the first base layer 20A after heat sterilization. This effectively compensates for the difference in deformation between the first base layer 20A and the anchor coating layer 21. Consequently, damage to the deposited layer 22 can be suppressed, and degradation of the barrier properties of the deposited layer 22 can be prevented.

[0259] The softening temperature T1 of the first base layer 20A is not particularly limited as long as it is lower than the softening temperature T2 of the anchor coating layer 21, but is preferably between 115°C and 170°C. A softening temperature T1 of 115°C or higher prevents excessively low heat resistance of the first base layer 20A, making it less susceptible to softening during heat sterilization, thereby minimizing the risk of decreased adhesion to the anchor coating layer 21 or degradation of barrier properties. Furthermore, a softening temperature T1 of 170°C or lower can suppress a decrease in the flexibility of the first base layer 20A, further enhancing the adhesion strength between the first base layer 20A and the core layer 12.

[0260] From the perspective of imparting heat resistance to the first substrate layer 20A, the softening temperature T1 may be 120°C or higher, 125°C or higher, or 130°C or higher. From the perspective of imparting flexibility to the first substrate layer 20A, the softening temperature T1 may be 165°C or lower or 160°C or lower.

[0261] The first base material layer 20A may have only the softening temperature T1 or may have one or more softening temperatures higher than the softening temperature T1. When the first base material layer 20A has multiple softening temperatures, the lowest softening temperature is the softening temperature T1.

[0262] The thickness of the first substrate layer 20A is not particularly limited and may be, for example, 5 μm or greater, 10 μm or greater, or 15 μm or greater. Alternatively, the thickness of the first substrate layer 20A may be 100 μm or less, 80 μm or less, 60 μm or less, or 40 μm or less. When the thickness of the first substrate layer 20A is 5 μm or greater and 100 μm or less, wrinkling and sagging of the gas barrier layer 23 during formation are suppressed, resulting in excellent processability, such as ease of handling, of the first substrate layer 20A.

[0263] In addition, the base material layer 1 may be used instead of the first base material layer 20A.

[0264] [Adhesive layer] The adhesive layer 40A is a layer that bonds the barrier film 25 to the sealant layer 30A or the second substrate layer 10A. Examples of adhesives forming the adhesive layer 40A include polyurethane resins obtained by using a base agent composed of a polyester polyol, polyether polyol, acrylic polyol, carbonate polyol, or the like, and an adhesive containing a difunctional or higher-functional isocyanate compound. These polyols can be used alone or in combination of two or more. From the perspective of heat resistance during heat sterilization (heat sterilization tolerance), a two-component curing urethane adhesive is preferably used.

[0265] To promote adhesion, the above-mentioned adhesives may be compounded with carbodiimide compounds, oxazoline compounds, epoxy compounds, phosphorus compounds, silane coupling agents, and the like. From an environmental perspective, the adhesive used to form the adhesive layer 40A may be an adhesive whose polymer components are derived from biomass or a biodegradable adhesive. Furthermore, the adhesive may have barrier properties.

[0266] From the viewpoint of obtaining the desired bonding strength, followability, and processability, the coating amount of the adhesive may be, for example, 0.5 to 10 g / m 2 The amount of adhesive after removing the solvent by heating and drying can be 0.1~10g / m 2The amount of adhesive after removing the solvent is 0.1g / m 2 When the amount of adhesive after removing the solvent is 10 g / m 2 Then, peeling inside the adhesive is unlikely to occur, and the lamination strength in the laminate 100A is unlikely to decrease.

[0267] [Sealing agent layer] The sealant layer 30A includes a polypropylene film, which includes a polypropylene resin.

[0268] Examples of the polypropylene resin include homopolypropylene and propylene-α-olefin copolymers, which can be used alone or in combination of two or more.

[0269] The polypropylene resin contained in the polypropylene film may be any of a polypropylene resin derived from fossil fuels, a recycled polypropylene resin, and a polypropylene resin derived from biomass. These polypropylene resins may be used alone or in combination of two or more.

[0270] The sealant layer 30A may further contain additives as needed. Examples of the additives include antioxidants, stabilizers, lubricants such as calcium stearate, fatty acid amide, and erucamide, organic additives such as antistatic agents, and particulate lubricants such as silica, zeolite, syloid, hydrotalcite, and silicon particles.

[0271] The polypropylene film contained in the sealant layer 30A may be a stretched film or an unstretched film, but is preferably an unstretched film from the viewpoint of lowering the melting point and facilitating heat sealing.

[0272] The thickness of the sealant layer 30A is not particularly limited and may, for example, be 5 μm or greater, 10 μm or greater, 15 μm or greater, 30 μm or greater, or 50 μm or greater. Furthermore, the thickness of the first substrate layer 20A may be 150 μm or less, 125 μm or less, 100 μm or less, or 80 μm or less. When the sealant layer 30A has a thickness of 5 μm or greater, packaging containers such as packaging bags are less susceptible to damage. When the sealant layer 30A has a thickness of 150 μm or less, the sealant layer 30A maintains heat-sealing properties, further reducing the likelihood of sealing defects.

[0273] In addition, the sealant layer 5 may be used instead of the sealant layer 30A.

[0274] (Laminated body) The oxygen permeability of the laminate 100A at 30°C and 70 RH% is not particularly limited, but is preferably 200 cc / m 2 ·day·atm or less.

[0275] In this case, the oxygen permeability at 30°C and 70 RH% exceeds 200 cc / m 2 When a packaging container is manufactured using the stacked body 100A and a content is stored in the packaging container to manufacture a packaged product, the degradation of the content due to oxygen can be effectively suppressed compared to the case of ·day·atm.

[0276] The oxygen permeability of the laminate 100A at 30°C and 70 RH% is more preferably 100 cc / m 2 ·day·atm or less, particularly preferably 50cc / m 2 ·day·atm or less.

[0277] In the laminate 100A, the proportion of the polypropylene resin in the laminate 100A is not particularly limited, but is preferably 90% by mass or greater. By setting the proportion of the polypropylene resin in the laminate 100A to 90% by mass or greater, the laminate 100A can have higher recyclability.

[0278] The proportion of the polypropylene resin in the entire laminate 100A is more preferably 92% by mass or more, particularly preferably 94% by mass or more.

[0279] The thickness of the laminate 100A is not particularly limited, but is preferably 200 μm or less. If the thickness of the laminate 100A is 200 μm or less, the heat sealability during packaging container production is less likely to decrease, and the laminate 100A is less likely to bend, making it easier to use as a packaging container. The thickness of the laminate 100A can be 40 μm or greater, 80 μm or greater, or 100 μm or greater. If the thickness of the laminate 100A is 40 μm or greater, the laminate 100A is less likely to bend, making it easier to manufacture bags using the laminate 100A, and the bags are more likely to stand on their own after manufacture.

[0280] <Method for producing laminate> Next, a method for producing the laminate 100A will be described.

[0281] First, the second base material layer 10A is prepared. As the second base material layer 10A, a peak intensity ratio A (=I 110 / I 040 ) is 0.75 or more. The peak intensity ratio A can be prepared by, for example, adjusting the amount of a crystallization nucleating agent blended into the raw material of the polypropylene film or adjusting the stretching conditions of the polypropylene film before stretching.

[0282] On the other hand, the barrier film 25 is prepared.

[0283] To this end, first, the first base material layer 20A is prepared.

[0284] Next, the anchor coating layer 21 is formed on the first base layer 20A. The anchor coating layer 21 can be obtained by applying the anchor coating layer-forming composition on the surface of the first base layer 20A and drying it.

[0285] Next, a vapor-deposited layer 22 as an inorganic oxide layer is formed on the anchor coating layer 21 .

[0286] The deposited layer 22 can be formed using a vacuum evaporation method, a sputtering method, an ion plating method, a plasma vapor deposition method (CVD), or the like. Among them, if productivity is taken into consideration, the vacuum evaporation method is most preferred. As a heating method used in the vacuum evaporation method, it is preferred to use any one of an electron beam heating method, a resistance heating method, and an induction heating method, but if the wide range of selectivity of the evaporation material is taken into consideration, an electron beam heating method is more preferred. In addition, in order to improve the adhesion between the evaporation layer 22 and the first substrate layer 20A and the density of the evaporation layer 22, evaporation can also be performed using a plasma-assisted method or an ion beam-assisted method. In addition, evaporation can also be performed using a reactive evaporation method in which various gases such as oxygen are blown into the evaporation film to improve the transparency of the evaporation film.

[0287] When forming the anchor coating layer 21 and the first base layer 20A, the anchor coating layer 21 and the first base layer 20A are formed so that the softening temperature T1 of the first base layer 20A is lower than the softening temperature T2 of the anchor coating layer 21 when the softening temperatures of the anchor coating layer 21 and the first base layer 20A are measured by local thermal analysis (LTA).

[0288] Next, the gas barrier layer 23 is formed on the vapor-deposited layer 22. In this way, the barrier film 25 is obtained.

[0289] The gas barrier layer 23 can be obtained by applying the gas barrier layer-forming composition on the vapor-deposited layer 22 and drying the composition.

[0290] Examples of the coating method include wet film-forming methods such as gravure coating, dip coating, reverse coating, wire bar coating, and die coating.

[0291] Next, the second base material layer 10A is formed on the gas barrier layer 23 of the barrier film 25 via the adhesive layer 40A.

[0292] On the other hand, the sealant layer 30A is formed on the first base material layer 20A of the barrier film 25 via the adhesive layer 40A.

[0293] The laminated body 100A is obtained in the above manner.

[0294] <Packaging Products> Next, refer to Figure 6 A second embodiment of the packaging product disclosed herein will be described. Figure 6: is a side view showing a second embodiment of the packaged product of the present disclosure. Figure 6 In, with Figure 5 The same components are denoted by the same reference numerals, and redundant descriptions are omitted.

[0295] like Figure 6 As shown, the packaged product 400 includes a packaging container 300 and contents C stored in the packaging container 300 .

[0296] The packaged product 400 can be obtained by heat-sealing a portion of the periphery of the stack 100A with the sealant layers 30A facing each other using a pair of stacks 100A, then heat-sealing the remaining periphery of the stack 100A after accommodating the contents C. In this manner, the packaging container 300 is also obtained.

[0297] In the packaged product 400, the barrier film 25 has excellent lamination strength with the sealant layer 30A serving as another film even after heat sterilization, and the laminate has excellent interlayer adhesion even after heat sterilization, thereby suppressing the occurrence of interlayer delamination even after heat sterilization.

[0298] Furthermore, the packaging container 300 obtained using the laminate 100A comprises, in this order, a second substrate layer 10A, a barrier film 25, and a sealant layer 30A, wherein the substrate layer of the barrier film 25 is the first substrate layer 20A, and the second substrate layer 10A, the first substrate layer 20A, and the sealant layer 30A all comprise polypropylene film. The peak intensity ratio A is 0.75 or greater, resulting in the laminate 100A having excellent recyclability and maintaining excellent interlayer adhesion even after heat sterilization. Consequently, delamination in the laminate 100A can be suppressed even after heat sterilization. Furthermore, the packaging container 300 remaining after the contents C are discharged from the packaged product 400 has excellent recyclability.

[0299] Alternatively, the packaged product 400 can be obtained by folding a single laminate 100A, heat-sealing a portion of the periphery of three sides of the laminate 100A with the sealant layers 30A facing each other, placing the contents C therein, and then heat-sealing the remaining periphery of the laminate 100A. In this case, the packaging container 300 is also obtained.

[0300] Examples of the packaging container 300 include packaging bags, laminated tube containers, and liquid paper containers.

[0301] For example, in the third embodiment, in the barrier film 25, the vapor deposition layer 22 and the gas barrier layer 23 are provided between the second substrate layer 10A and the first substrate layer 20A, but it may also be provided as follows. Figure 7 As in the laminated body 200 of the fourth embodiment shown, the vapor deposited layer 22 and the gas barrier layer 23 are provided between the sealant layer 30A and the first base layer 20A instead of being provided between the second base layer 10A and the first base layer 20A.

[0302] The laminate 200 has excellent recyclability and can have excellent interlayer adhesion even after heat sterilization.

[0303] Furthermore, the vapor-deposited layer 22 and the gas barrier layer 23 may be provided between the second base layer 10A and the first base layer 20A, and between the sealant layer 30A and the first base layer 20A.

[0304] In the barrier film 25 , the vapor deposited layer 22 and the gas barrier layer 23 are arranged in this order from the first base layer 20A side. Alternatively, the gas barrier layer 23 and the vapor deposited layer 22 may be arranged in this order from the first base layer 20A side.

[0305] Furthermore, the outline of the present disclosure is as follows.

[0306] [1] A barrier film comprising, in order, a substrate layer containing a polypropylene resin, an anchor coating layer, and an inorganic oxide layer, wherein the substrate layer has a contact layer in contact with the anchor coating layer, wherein, when the softening temperatures of the anchor coating layer and the contact layer are measured by local thermal analysis, the softening temperature T1 of the contact layer is lower than the softening temperature T2 of the anchor coating layer.

[0307] [2] The barrier film according to [1], wherein the softening temperature T2 of the anchor coating layer is within a range of 140° C. to 195° C.

[0308] [3] The barrier film according to [1] or [2], wherein the substrate layer further comprises a core layer on the side of the contact layer opposite to the anchor coating layer, the contact layer is a skin layer, and the softening temperature T1 of the contact layer is lower than the softening temperature T3 of the core layer.

[0309] [4] The barrier film according to any one of [1] to [3], wherein T2-T1 is 70°C or less.

[0310] [5] The barrier film according to any one of [1] to [4], wherein the contact layer comprises a copolymer of propylene and an α-olefin.

[0311] [6] The barrier film according to any one of [1] to [5], wherein the anchor coating layer contains a polyurethane resin.

[0312] [7] The barrier film according to any one of [1] to [6], wherein the anchor coating layer has a thickness of 0.05 to 2 μm.

[0313] [8] A laminate comprising the barrier film according to any one of [1] to [7] and a sealant layer, wherein the sealant layer comprises a polyolefin.

[0314] [9] The laminate according to [8], further comprising a second base material layer on the surface of the barrier film opposite to the sealant layer, wherein the second base material layer comprises a polyolefin resin.

[0315]

[10] The laminate according to [9] comprises the second substrate layer, the barrier film and the sealant layer in this order, wherein the substrate layer of the barrier film is the first substrate layer, the second substrate layer, the first substrate layer and the sealant layer all comprise polypropylene film, and in an X-ray diffraction pattern obtained by X-ray diffraction measurement of the second substrate layer, the intensity I of the (110) plane peak is 110 The intensity of the peak relative to the (040) plane is I 040 The ratio, that is, the peak intensity ratio A, is 0.75 or more.

[0316]

[11] The laminate according to [9] or

[10] , wherein the second substrate layer is an unstretched film and the first substrate layer is a stretched film.

[0317]

[12] The laminate according to

[10] or

[11] , further comprising the inorganic oxide layer and the gas barrier layer between at least one of the first substrate layer and the second substrate layer and between the first substrate layer and the sealant layer.

[0318]

[13] The laminate according to

[12] , further comprising the inorganic oxide layer and the gas barrier layer between the first substrate layer and the second substrate layer.

[0319]

[14] The laminate according to

[12] or

[13] , wherein the inorganic oxide layer is a vapor-deposited layer, and the vapor-deposited layer contains at least one of aluminum oxide and silicon oxide.

[0320]

[15] The laminate according to any one of

[12] to

[14] , wherein the gas barrier layer is a layer formed of a coating liquid containing a silicon compound and a water-soluble polymer, the silicon compound contains at least one of a first silicon compound and a second silicon compound, the first silicon compound contains at least one of a silicon alkoxide represented by the following general formula (1) and a hydrolyzate thereof, and the second silicon compound contains at least one of a silane coupling agent represented by the following general formula (2) and a hydrolyzate thereof.

[0321] (In the above general formula (1), OR 1represents a hydrolyzable group.) (In the above general formula (2), OR 3 Represents a hydrolyzable group, R 2 represents a monovalent organic group. n is an integer greater than or equal to 1.

[16] The laminate according to any one of

[10] to

[15] , wherein the oxygen permeability at 30°C and 70 RH% is 200 cc / m 2 ·day·atm or less.

[0322]

[17] A laminate according to any one of

[10] to

[16] , wherein the anchor coating layer comprises an organic polymer, and the organic polymer comprises at least one of a polyacrylic resin, a polyol resin, a polyurethane resin, a polyamide resin, and a reaction product of these resins.

[0323]

[18] The laminate according to any one of

[10] to

[17] , wherein the thickness of the anchor coating layer is 0.01 to 1 μm.

[0324]

[19] A packaging container formed using the laminate according to any one of [8] to

[18] .

[0325]

[20] A packaged product comprising a packaging container and contents housed in the packaging container, wherein the packaging container is the packaging container described in

[19] .

[0326] Example Hereinafter, the present disclosure will be described in more detail with reference to Examples and Comparative Examples, but the present disclosure is not limited to these Examples.

[0327] <Preparation of Anchor Coat Layer-Forming Composition> Anchor coating layer-forming compositions AC1, AC2, and AC3 were prepared as follows.

[0328] (AC1) Acrylic polyol and toluene diisocyanate were mixed so that the number of NCO groups in the toluene diisocyanate was equal to the number of OH groups in the acrylic polyol. The mixture was diluted with ethyl acetate to a solid content (the total amount of acrylic polyol and toluene diisocyanate) of 5% by mass. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture to a total of 5 parts by mass relative to 100 parts by mass of the total amount of acrylic polyol and toluene diisocyanate, and the mixture was mixed to prepare an anchor coating layer-forming composition AC1.

[0329] (AC2) Anchor coat layer-forming composition AC2 was prepared by mixing Takelac WPB-341 (manufactured by Mitsui Chemicals, Inc.) and isocyanate silane KBE-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) at a solid content ratio of 9:1.

[0330] (AC3) An anchor coat layer-forming composition AC3 (solid content: 2 mass %) was prepared by blending acrylic polyol ACRYDIC CL-1000 (manufactured by DIC Corporation) and isocyanate compound toluene diisocyanate (TDI)-type curing agent Coronate 2030 (manufactured by Tosoh Corporation) at a solid content mass ratio of 6:4, using ethyl acetate as a diluent solvent.

[0331] <Preparation of coating solution> Coating liquids as gas barrier layer-forming compositions used in Examples and Comparative Examples were prepared as follows.

[0332] (Coating liquid 1) A solution prepared by mixing the following liquids A, B, and C at a mixing ratio (mass ratio) of 70 / 20 / 10.

[0333] Solution A: A hydrolyzed solution (solid content 5 mass % (SiO2 conversion)) obtained by adding 72.1 g of hydrochloric acid (0.1 N) to a mixed solution of 17.9 g of tetraethoxysilane and 10 g of methanol and stirring for 30 minutes for hydrolysis.

[0334] Solution B: A water / methanol solution containing 5% by mass of polyvinyl alcohol (water / methanol weight ratio = 95 / 5).

[0335] Solution C: A mixture of β-(3,4-epoxycyclohexyl)trimethoxysilane and isopropyl alcohol (IPA solution) was slowly added with hydrochloric acid (1N), stirred for 30 minutes, and then hydrolyzed with water / IPA solution (water / IPA weight ratio = 1 / 1) to obtain a hydrolyzed solution (solid content 5% by mass (R 2 Si(OH)3 conversion), R 2 represents 3,4-epoxycyclohexyl).

[0336] (Coating liquid 2) A solution prepared by mixing the following liquids A, B, and C at a mixing ratio (mass ratio) of 45 / 45 / 10.

[0337] Solution A: Tetraethoxysilane (trade name: KBE04, solid content: 100%, manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter also referred to as "TEOS"), methanol (manufactured by Kanto Chemical Co., Ltd.), and 0.1N hydrochloric acid (manufactured by Kanto Chemical Co., Ltd.) were mixed in a ratio of 17 / 10 / 73 (mass ratio), and the TEOS was hydrolyzed to obtain a solution (5 mass % (SiO2 conversion) hydrolyzed solution of TEOS).

[0338] Liquid B: 5% by mass aqueous solution of polyvinyl alcohol (trade name: Kuraray Poval 60-98, manufactured by Kuraray Co., Ltd., hereinafter also referred to as “PVA”).

[0339] Liquid C: 1,3,5-tris(3-methoxysilylpropyl)isocyanurate (trade name: X-12-965P, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent was diluted with a mixed solvent of water / IPA = 1 / 1 (mass ratio) to a solid content of 5 mass % (R 2 Si(OH)3 conversion) formed by the hydrolysis solution.

[0340] [Production of barrier film] <Example 1> An ethylene-1-butene-propylene random copolymer resin (ethylene content: 2.5 mol%, 1-butene content: 3.5 mol%, propylene content: 94.0 mol%) was used as the material for the skin layer, and a homopolypropylene resin was used as the material for the core layer. These resins were coextruded and then biaxially stretched to produce a square-shaped substrate film (substrate layer) with a total thickness of 20 μm.

[0341] Next, the anchor coating layer-forming composition AC1 was applied onto the skin layer of the base material layer by gravure coating and dried in an oven at 100° C. for 10 seconds to form an anchor coating layer having a thickness of 0.12 μm.

[0342] Next, silicon oxide was vapor-deposited on the anchor coating layer by a reactive vapor deposition method using high-frequency excitation ion plating in an oxygen atmosphere under reduced pressure, thereby forming a vapor-deposited layer of an inorganic oxide with a thickness of 30 nm.

[0343] Next, the coating liquid 1 was applied onto the vapor deposited layer by gravure coating and dried at 80° C. for 20 seconds to form a gas barrier layer having a thickness of 0.3 μm, thereby producing a barrier film.

[0344] <Example 2> A barrier film was produced in the same manner as in Example 1, except that a 1-butene-propylene random copolymer resin (1-butene content: 4.5 mol %, propylene content: 95.5 mol %) was used as the material for the skin layer.

[0345] <Example 3> A barrier film was produced in the same manner as in Example 1 except that the anchor coating layer-forming composition AC2 was applied by gravure coating on the skin layer of the substrate layer and dried in an oven at 100° C. for 10 seconds to form an anchor coating layer having a thickness of 1.5 μm.

[0346] <Example 4> A barrier film was produced in the same manner as in Example 1, except that the anchor coating layer-forming composition AC1 was applied on the skin layer of the substrate layer by gravure coating and dried in an oven at 40° C. for 30 seconds to form an anchor coating layer.

[0347] <Comparative Example 1> A barrier film was produced in the same manner as in Example 1, except that an ethylene-propylene block copolymer resin (ethylene content: 1 mol %, propylene content: 99 mol %) was used as the material of the skin layer.

[0348] <Example 5> A barrier film was produced in the same manner as in Example 1, except that an ethylene-propylene random copolymer resin (ethylene content: 2.5 mol %, propylene content: 97.5 mol %) was used as the material of the skin layer.

[0349] <Example 6> A barrier film was produced in the same manner as in Example 1, except that an ethylene-propylene random copolymer resin (ethylene content: 10 mol %, propylene content: 90 mol %) was used as the material of the skin layer.

[0350] <Example 7> A barrier film was produced in the same manner as in Example 1 except that the anchor coating layer-forming composition was dried in an oven at 120° C. when forming the anchor coating layer on the skin layer of the substrate layer.

[0351] <Example 8> A barrier film was produced in the same manner as in Example 1 except that the anchor coating layer-forming composition AC2 was applied by gravure coating on the skin layer of the substrate layer and dried in a 120° C. oven for 10 seconds to form a 1.5 μm-thick anchor coating layer.

[0352] <Comparative Example 2> A barrier film was produced in the same manner as in Example 1 except that the anchor coating layer-forming composition AC2 was applied by gravure coating on the skin layer of the substrate layer and dried in a 40° C. oven for 30 seconds to form a 1.5 μm-thick anchor coating layer.

[0353] [Production of Laminated Body] A 60 μm thick unstretched polypropylene film was adhered to the gas barrier layer side of the barrier films produced in Examples 1 to 8 and Comparative Examples 1 and 2 by dry lamination via a two-component curable urethane adhesive to produce a quadrilateral laminate.

[0354] [Steaming treatment] Two sheets each of the laminates produced in Examples 1 to 8 and Comparative Examples 1 and 2 were prepared and stacked with the sealant layers facing each other. Three of the four sides were heat-sealed to create packaging bags. Water was then filled from the remaining side, and the remaining side was finally heat-sealed to produce packaged products. These packaged products were then retorted at 130°C for 60 minutes for sterilization.

[0355] [evaluate] <Softening Temperature Measurement> The softening temperatures of the skin layer of the substrate layer and the anchor coating layer were measured by the method shown below.

[0356] The packaged product was retorted, and a laminate was cut out from the packaging bag after the water was drained. The front and back surfaces of the laminate were subjected to a corona treatment at 0.20 kW using a corona treater (trade name: CT-0212) manufactured by Kasuga Electric Co., Ltd.

[0357] After corona treatment of the front and back sides of the laminate, the laminate was cut into rectangular pieces with a base of 1.0 mm and a height of 5.0 mm using a razor to obtain cut pieces. The cut pieces were embedded with a photocurable resin and cured using a halogen lamp (manufactured by KenkoTokina, trade name: KTX-100R) to obtain blocks. The photocurable resin used was D-800 (trade name) manufactured by Toagosei Co., Ltd. The light-cured block was fixed with an insert using an AFM sample holder. The cross section of the sample was cut using a glass knife at room temperature (25°C). After cutting using a cross-section cutting device, the final cross section was cut using a diamond knife at a cutting speed of 1.0 mm / s and a cutting film thickness of 100 nm at low temperature (-40°C). Cutting was completed when the cross section of the laminate was exposed to obtain a measurement sample. An ultramicrotome (manufactured by Leica, trade name: EM UC7) and a cryosystem (manufactured by Leica, trade name: EM FC7) were used as cross-section cutting devices. The cutting direction of the blade was parallel to the interface between adjacent layers and perpendicular to the long side of the rectangular section. The sample for measurement was fixed with an insert in the AFM sample holder for softening temperature measurement.

[0358] An atomic force microscope (AFM) was used, using the Oxford Instruments MFP-3D-SA (trade name), a Ztherm System (trade name) as the local thermal analysis option, and an Anasys Instruments AN2-200 (trade name) with a spring constant of 0.5 to 3.5 N / m. The softening temperature and cross-sectional shape of the test specimens were measured. The softening temperature was measured at the center of the base layer's skin layer and the anchor coating layer in the thickness direction.

[0359] At this time, when setting the cantilever's contact pressure (the change in the cantilever's deflection (Deflection)), the change in Deflection voltage is set to 0.2V in the skin and core layers of the substrate layer and 1.5V in the anchor coating, the voltage application rate (heating rate) is set to 0.5V / second, the maximum applied voltage is set to 5.5V, and the sample surface is heated after Detrend correction. As a result, the sample surface expands and the cantilever position rises. If the sample surface is further heated, the sample surface softens and the cantilever position drops. The measurement ends when the cantilever drops 10nm. When the Z displacement does not drop 10nm from the change point and reaches the maximum applied voltage, the maximum applied voltage during Detrend correction and measurement is increased by 0.5V, and the measurement is performed again.

[0360] The voltage applied at the point where the cantilever's vertical height (Z displacement) was the largest was defined as the voltage applied at the softening point, and the voltage value was read.

[0361] To calculate the softening temperature of the sample, calibration curves were created that matched the measurement conditions for the base layer's skin layer and the anchor coating layer. Calibration samples used were the following four polymer materials, whose melting points (melting peak temperatures) had been previously measured using a differential scanning calorimeter (DSC). Cross-section specimens of each material were prepared under conditions below the glass transition temperature.

[0362] Polycaprolactone pellets (melting point: 60°C) Low-density polyethylene pellets (melting point: 112°C) Polypropylene pellets (melting point: 166°C) · Biaxially stretched polyethylene terephthalate film (melting point: 255°C) Cross-section specimens were prepared using an ultramicrotome and a cryosystem at -80°C for polycaprolactone, -140°C for low-density polyethylene, -40°C for polypropylene, and room temperature (25°C) for polyethylene terephthalate. Measurement conditions were: a voltage application rate (temperature increase rate) of 0.5 V / s, and a maximum applied voltage of 3.5 V for polycaprolactone, 5 V for low-density polyethylene, 6 V for polypropylene, and 7.8 V for polyethylene terephthalate. The cantilever contact pressure (change in cantilever deflection) was set to 0.2 V using the calibration curves for the skin and core layers of the substrate layer and 1.5 V using the calibration curve for the anchor coating layer. After detrend correction, the sample surface was heated, and the applied voltage at the softening point was measured. The measurement position of the calibration sample was changed, and the applied voltage at the softening point was measured 10 times. The average value of the applied voltage at the softening point and the melting point (melting peak temperature) measured by DSC were approximated with a cubic function using the least squares method to create a standard curve and a calibration curve.

[0363] Using a calibration curve for applied voltage and temperature, the temperatures corresponding to the applied voltage at the softening points of the base layer's skin layer and the anchor coating layer were determined, respectively, and these temperatures were designated as softening temperatures T1 and T2. The value of T2-T1 was also calculated. The results are shown in Table 1 or Table 2.

[0364] <Gas Barrier Properties> Gas barrier properties were evaluated based on oxygen permeability. For oxygen permeability, water was removed from the packaged product after retorting, and the laminate was cut out from the resulting packaging bag and measured. The measurement was performed using an oxygen permeability tester (Modern Control, OXTRAN 2 / 20) at a temperature of 30°C and a relative humidity of 70%. The measurement method was based on JIS K-7126, Method B (isobaric method), and ASTM D3985-81, and the measured value was expressed in [cm 3 (STP) / m 2 The results of oxygen permeability are shown in Table 1 or Table 2.

[0365] <Lamination Strength> After removing water from the retorted packaging product, a 1.5 cm x 10 cm laminate was cut from the resulting packaging bag. The laminate was then evaluated for lamination strength between the barrier film and the sealant layer. Lamination strength was measured in accordance with JIS K6854 using a test width of 15 mm, a peel speed of 300 mm / min, and a T-shaped peel angle. The measured values ​​are expressed in [N / 15 mm]. A lamination strength of 2 N / 15 mm or greater indicates excellent lamination strength between the barrier film and the sealant layer. The lamination strength results are shown in Table 1 or Table 2.

[0366] <Example 9> First, as the second base layer, a 50 μm thick square unstretched polypropylene (PP) film 1 was prepared as shown in Table 3. The PP film 1 was subjected to X-ray diffraction measurement described later. The peak intensity corresponding to the (110) plane was 1.33° relative to the peak intensity corresponding to the (040) plane. 040 The ratio of the peak intensity ratio A (=I 110 / I 040 ) is 1.03 as shown in Table 3. The PP film 1 has a three-layer structure, and all the layers are composed of a polypropylene copolymer resin.

[0367] On the other hand, a 20 μm-thick biaxially stretched polypropylene film (trade name “ME-1”, OPP, manufactured by Mitsui Chemicals Tohcello, Ltd.; hereinafter also referred to as “PP film 5”) was prepared as a first base material layer.

[0368] Next, the anchor coating layer-forming composition AC3 prepared above was applied to one side of the first substrate layer by gravure coating to form a coating film. The coating film was then dried in an oven at 100°C for 10 seconds to form an anchor coating layer having a thickness of 0.1 μm.

[0369] Next, a silicon oxide vapor-deposited layer was formed on the anchor coating layer to a thickness of 25 nm. The silicon oxide vapor-deposited layer was formed by evaporating silicon oxide using an electron beam vacuum deposition method using electron beam heating.

[0370] Next, the gas barrier layer-forming composition, coating solution 2 prepared as described above, was applied onto the silicon oxide vapor-deposited layer by gravure coating to form a coating film. The coating film was then dried in an oven at 60°C for 60 seconds, thereby forming a gas barrier layer with a thickness of 0.3 μm.

[0371] In this way, a barrier film (first substrate layer / anchor coating layer / silicon oxide vapor-deposited layer / gas barrier layer) was obtained.

[0372] The second substrate layer and the barrier film were then laminated using a dry lamination method, with the gas barrier layer of the barrier film facing the second substrate layer. A two-component curing adhesive ("A525 / A52" manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) was used and cured to form the adhesive layer. This resulted in a second structure (first substrate layer / anchor coating layer / vapor-deposited silicon oxide layer / gas barrier layer / adhesive layer / second substrate layer).

[0373] Next, the second structure and a 60 μm thick unstretched polypropylene film (trade name "Torayfan ZK207," manufactured by Toray Industries, Ltd.) serving as a sealant layer were laminated using a dry lamination method, with the first substrate layer of the second structure facing the sealant layer. A two-component curing adhesive ("A525 / A52," manufactured by Mitsui Chemicals, Inc.) was used and cured to form the adhesive layer.

[0374] In this way, a quadrilateral laminate (sealant layer / adhesive layer / first base layer / anchor coating layer / silicon oxide vapor-deposited layer / gas barrier layer / adhesive layer / second base layer) was obtained.

[0375] The proportion of the polypropylene resin in the entire laminate obtained in this manner was 91% by mass.

[0376] <Example 10> A laminate (sealant layer / adhesive layer / first substrate layer / anchor coating layer / silicon oxide vapor-deposited layer / gas barrier layer / adhesive layer / second substrate layer) was prepared in the same manner as in Example 9, except that a 30 μm thick unstretched polypropylene (PP) film 2 was used as the second substrate layer, as shown in Table 3. Furthermore, X-ray diffraction analysis of the PP film 2, described below, revealed a peak intensity ratio A of 0.81, as shown in Table 3. The PP film 2 had a three-layer structure, all of which were composed of a polypropylene copolymer resin.

[0377] The proportion of the polypropylene resin in the entire laminate obtained in this manner was 92% by mass.

[0378] <Example 11> As the second base material layer, an unstretched polypropylene (PP) film 2 (I) having a thickness of 30 μm was prepared as shown in Table 3. 110 / I 040 =0.81).

[0379] This second substrate layer and a barrier film prepared in the same manner as in Example 9 were then laminated using a dry lamination method, with the first substrate layer of the barrier film facing the second substrate layer. A two-component curing adhesive ("A525 / A52" manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) was used and cured to form an adhesive layer. This resulted in a third structure (second substrate layer / adhesive layer / first substrate layer / anchor coating layer / evaporated silicon oxide layer / gas barrier layer).

[0380] Next, the third structure and a 60 μm-thick unstretched polypropylene film (trade name "Torayfan ZK207," manufactured by Toray Industries, Ltd.) serving as a sealant layer were laminated using a dry lamination method, with the gas barrier layer of the third structure facing the sealant layer. A two-component curing adhesive ("A525 / A52," manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) was used and cured to form the adhesive layer. This resulted in a laminate (second substrate layer / adhesive layer / first substrate layer / anchor coating layer / silicon oxide vapor-deposited layer / gas barrier layer / adhesive layer / sealant layer).

[0381] The proportion of the polypropylene resin in the entire laminate obtained in this manner was 91% by mass.

[0382] <Example 12> As the second substrate layer, a 25 μm-thick stretched polypropylene (PP) film 3 was prepared as shown in Table 3. A laminate (sealant layer / adhesive layer / first substrate layer / anchor coating layer / vapor-deposited silicon oxide layer / gas barrier layer / adhesive layer / second substrate layer) was produced in the same manner as in Example 9. X-ray diffraction analysis of the PP film 3, described below, revealed a peak intensity ratio A of 0.72 as shown in Table 3. The PP film 3 had a three-layer structure, with the middle layer composed of a homopolypropylene resin and the outer and inner layers composed of a polypropylene copolymer resin. The inner layer was the adhesive layer-side layer that bonded the gas barrier layer to the second substrate layer.

[0383] The proportion of the polypropylene resin in the entire laminate obtained in this manner was 92% by mass.

[0384] <Example 13> As the second substrate layer, a 25 μm-thick stretched polypropylene (PP) film 4 was prepared as shown in Table 3. A laminate (sealant layer / adhesive layer / first substrate layer / anchor coating layer / silicon oxide vapor-deposited layer / gas barrier layer / adhesive layer / second substrate layer) was produced in the same manner as in Example 9. X-ray diffraction analysis of the PP film 4, described below, revealed a peak intensity ratio A of 0.48, as shown in Table 3. The PP film 4 had a three-layer structure: the outer and middle layers were composed of a homopolypropylene resin, and the inner layer was composed of a polypropylene copolymer resin.

[0385] The proportion of the polypropylene resin in the entire laminate obtained in this manner was 91% by mass.

[0386] <Example 14> As the second base material layer, an unstretched polypropylene (PP) film 2 (I) having a thickness of 30 μm was prepared as shown in Table 3. 110 / I 040 =0.81).

[0387] Separately, a 20 μm-thick biaxially oriented polypropylene film (hereinafter also referred to as "PP film 6") was prepared as the first substrate layer. This biaxially oriented polypropylene film consisted of a core layer formed of homopolypropylene and a skin layer formed of an ethylene-1-butene-propylene random copolymer resin (ethylene content: 2.5 mol%, 1-butene content: 3.5 mol%, propylene content: 94.0 mol%).

[0388] Next, the anchor coating layer-forming composition AC1 prepared above was applied to the skin layer of the first substrate layer by gravure coating to form a coating film. The coating film was then dried in an oven at 100°C for 10 seconds to form an anchor coating layer having a thickness of 0.12 μm.

[0389] Next, a silicon oxide vapor-deposited layer was formed on the anchor coating layer to a thickness of 30 nm. The silicon oxide vapor-deposited layer was formed by evaporating silicon oxide using an electron beam vacuum deposition method using electron beam heating.

[0390] Next, the gas barrier layer-forming composition, coating solution 1 prepared as described above, was applied onto the silicon oxide vapor-deposited layer by gravure coating to form a coating film. The coating film was then dried in an 80°C oven for 20 seconds to form a 0.3 μm thick gas barrier layer.

[0391] In this way, a barrier film (first substrate layer / anchor coating layer / silicon oxide vapor-deposited layer / gas barrier layer) was obtained.

[0392] The second substrate layer and the barrier film were then laminated using a dry lamination method, with the first substrate layer of the barrier film facing the second substrate layer. A two-component curing adhesive ("A525 / A52" manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) was used and cured to form an adhesive layer. This resulted in a third structure (second substrate layer / adhesive layer / first substrate layer / anchor coating layer / evaporated silicon oxide layer / gas barrier layer).

[0393] Next, the third structure and a 60 μm-thick unstretched polypropylene film (trade name "Torayfan ZK207," manufactured by Toray Industries, Ltd.) serving as a sealant layer were laminated using a dry lamination method, with the gas barrier layer of the third structure facing the sealant layer. A two-component curing adhesive ("A525 / A52," manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) was used and cured to form the adhesive layer. This resulted in a laminate (second substrate layer / adhesive layer / first substrate layer / anchor coating layer / silicon oxide vapor-deposited layer / gas barrier layer / adhesive layer / sealant layer).

[0394] <Example 15> As the second base material layer, an unstretched polypropylene (PP) film 2 (I) having a thickness of 30 μm was prepared as shown in Table 3. 110 / I 040 =0.81).

[0395] Meanwhile, a 20 μm-thick biaxially oriented polypropylene film (hereinafter also referred to as "PP film 7") was prepared as the first substrate layer. This biaxially oriented polypropylene film was composed of a core layer formed of homopolypropylene sandwiched between two skin layers formed of an ethylene-1-butene-propylene random copolymer resin (ethylene content: 2.5 mol%, 1-butene content: 3.5 mol%, propylene content: 94.0 mol%).

[0396] Next, the anchor coating layer-forming composition AC1 prepared above was applied to the skin layer of the first substrate layer by gravure coating to form a coating film. The coating film was then dried in an oven at 100°C for 10 seconds to form an anchor coating layer having a thickness of 0.12 μm.

[0397] Next, a silicon oxide vapor-deposited layer was formed on the anchor coating layer to a thickness of 30 nm. The silicon oxide vapor-deposited layer was formed by evaporating silicon oxide using an electron beam vacuum deposition method using electron beam heating.

[0398] Next, the gas barrier layer-forming composition, coating solution 1 prepared as described above, was applied onto the silicon oxide vapor-deposited layer by gravure coating to form a coating film. The coating film was then dried in an 80°C oven for 20 seconds to form a 0.3 μm thick gas barrier layer.

[0399] In this way, a barrier film (first substrate layer / anchor coating layer / silicon oxide vapor-deposited layer / gas barrier layer) was obtained.

[0400] The second substrate layer and the barrier film were then laminated using a dry lamination method, with the gas barrier layer of the barrier film facing the second substrate layer. A two-component curing adhesive ("A525 / A52" manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) was used and cured to form the adhesive layer. This resulted in a second structure (second substrate layer / adhesive layer / gas barrier layer / silicon oxide vapor-deposited layer / anchor coating layer / first substrate layer).

[0401] Next, the second structure and a 60 μm-thick unstretched polypropylene film (trade name "Torayfan ZK207," manufactured by Toray Industries, Ltd.) serving as a sealant layer were laminated using a dry lamination method, with the first substrate layer of the second structure facing the sealant layer. A two-component curing adhesive ("A525 / A52," manufactured by Mitsui Chemicals, Inc.) was used and cured to form the adhesive layer. This resulted in a laminate (second substrate layer / adhesive layer / gas barrier layer / silicon oxide vapor-deposited layer / anchor coating layer / first substrate layer / adhesive layer / sealant layer).

[0402] As described above, a laminate (sealant layer / adhesive layer / first base layer / anchor coating layer / silicon oxide vapor-deposited layer / gas barrier layer / adhesive layer / second base layer) was produced.

[0403] <Example 16> A laminate (sealant layer / adhesive layer / gas barrier layer / silicon oxide vapor-deposited layer / anchor coating layer / first substrate layer / adhesive layer / second substrate layer) was prepared in the same manner as in Example 14, except that a solvent-free adhesive was used as the adhesive for bonding the second substrate layer to the first substrate layer and the adhesive for bonding the gas barrier layer to the sealant layer. Furthermore, X-ray diffraction measurement of the PP film 2, described below, revealed a peak intensity ratio A of 0.48, as shown in Table 3.

[0404] [Peak Intensity Ratio A] The peak intensity ratio A of the PP films 1 to 4 as the second substrate layers used in Examples 9 to 16 was determined by X-ray diffraction measurement. Specifically, the peak intensity ratio A was determined as follows.

[0405] First, using a wide-angle X-ray diffractometer (ATX_G, manufactured by Rigaku Corporation), an out-of-plane measurement was performed. The X-ray incident angle was fixed at 0.5°, and the 2θ / θ diffraction pattern of the second substrate layer was scanned over a diffraction angle range of 10° to 30°. Characteristic X-rays, CuKα, were used as X-rays, and the optical system was a slit collimator. The X-rays were incident on the surface of the second substrate layer through an incident slit with an opening of 0.1 mm x 10 mm. The diffracted X-rays then passed through a Soller slit, serving as a light-receiving slit, and were detected by a detector.

[0406] From the obtained X-ray diffraction pattern, the peak intensity of the (110) plane at 2θ=14° and the peak intensity of the (040) plane at 2θ=17° were determined, and the peak intensity ratio A was calculated from these peak intensity values.

[0407] [Steaming treatment] Two sheets of the laminates produced in Examples 9 to 16 were prepared and stacked with the sealant layers facing each other. Three of the four sides were heat-sealed to produce packaging bags. Water was then filled from the remaining side, and the remaining side was finally heat-sealed to produce packaged products. These packaged products were then retorted at 120°C for 30 minutes.

[0408] [evaluate] <Softening Temperature Measurement> The softening temperature T1 of the first base material layer and the softening temperature T2 of the anchor coating layer were measured in the same manner as in Example 1. The value of T2-T1 was also calculated. The results are shown in Table 3.

[0409] <Interlayer Adhesion of Laminated Body> After removing water from the retorted packaging product, a 1.5 cm x 10 cm laminate was cut from the resulting packaging bag. The laminate was then evaluated for the lamination strength between the second substrate layer and the first substrate layer, and the lamination strength between the first substrate layer and the sealant layer, i.e., the interlayer adhesion of the laminate. Lamination strength was measured in accordance with JIS K6854 using a test width of 15 mm, a peel speed of 300 mm / min, and a T-type peel angle. The measured value is expressed in [N / 15 mm]. If the lamination strength is 2 N / 15 mm or greater, the barrier film is judged to have excellent lamination strength with the sealant layer or the second substrate layer, and the laminate is judged to have excellent interlayer adhesion. The results of interlayer adhesion are shown in Table 4.

[0410] As shown in the results in Tables 1 to 3, the packaged products of Examples 1 to 16 have greater lamination strength after retorting than the packaged product of Example 12 or 13.

[0411] In addition, in the laminates of Examples 9 to 13, the proportion of the polypropylene resin in the entire laminate was as high as 90% by mass or more.

[0412] From the above, it was confirmed that the barrier film according to the present disclosure has excellent lamination strength with other films even after heat sterilization.

[0413] Furthermore, it was confirmed that the laminated body of the present disclosure has excellent recyclability and has excellent interlayer adhesion even after heat sterilization.

[0414] Industrial applicability The barrier film of the present disclosure has excellent lamination strength with other films such as a sealant layer even after heat sterilization treatment such as boiling or retorting, and is therefore useful for laminated bodies of packaging containers.

[0415] Description of Reference Numerals 1 Substrate layer (first substrate layer), 2 Anchor coating layer, 3 Inorganic oxide layer, 4 Gas barrier layer, 5 Sealant layer (other film), 10 Barrier film, 11 Skin layer (contact layer), 12 Core layer, 20, 30 Laminated body, 31 Second substrate layer, 40 Packaging bag (packaging container), 100 Packaged product, 10A Second substrate layer, 20A First substrate layer, 21 Anchor coating layer, 22 Vapor-deposited layer, 23 Gas barrier layer, 25 First structure (barrier film), 30A Sealant layer, 40A Adhesive layer, 100A, 200 Laminated body, 300 Packaging container, 400 Packaged product, C Contents.

Claims

1. A barrier film comprising, in order, a substrate layer containing a polypropylene resin, an anchor coating layer, and an inorganic oxide layer, wherein the substrate layer has a contact layer in contact with the anchor coating layer, When the softening temperatures of the anchor coating and the contact layer are measured using local thermal analysis, the softening temperature T1 of the contact layer is lower than the softening temperature T2 of the anchor coating.

2. The barrier film according to claim 1, wherein The softening temperature T2 of the anchor coating layer is within a range of 140° C. to 195° C.

3. The barrier film according to claim 1, wherein The substrate layer further includes a core layer on a side of the contact layer opposite to the anchor coating layer. The contact layer is a skin layer. The softening temperature T1 of the contact layer is lower than the softening temperature T3 of the core layer.

4. The barrier film according to claim 1 or 2, wherein T2-T1 is 70°C or less.

5. The barrier film according to claim 1 or 2, wherein The contact layer comprises a copolymer of propylene and an α-olefin.

6. The barrier film according to claim 1 or 2, wherein The anchor coating contains a polyurethane resin.

7. The barrier film according to claim 1 or 2, wherein The thickness of the anchor coating is 0.05-2 μm. 8 . A laminate comprising the barrier film according to claim 1 or 2 and a sealant layer.

9. The laminate according to claim 8, wherein The barrier film further includes a second base layer on a surface opposite to the sealant layer, wherein the second base layer includes a polyolefin resin.

10. The laminate according to claim 9, comprising the second substrate layer, the barrier film, and the sealant layer in this order, wherein the substrate layer of the barrier film is the first substrate layer, the second substrate layer, the first substrate layer, and the sealant layer all comprise polypropylene films, and in an X-ray diffraction pattern obtained by X-ray diffraction measurement of the second substrate layer, the intensity I of the (110) plane peak is 110 The intensity of the peak relative to the (040) plane is I 040 The ratio, that is, the peak intensity ratio A, is 0.75 or more. The laminate according to claim 10 , wherein: The second substrate layer is an unstretched film, and the first substrate layer is a stretched film.

12. The laminate according to claim 10, wherein The inorganic oxide layer and the gas barrier layer are further provided between at least one of the first base layer and the second base layer and between the first base layer and the sealant layer.

13. The laminate according to claim 12, wherein The inorganic oxide layer and the gas barrier layer are further provided between the first base layer and the second base layer.

14. The laminate according to claim 13, wherein The inorganic oxide layer is a vapor-deposited layer, and the vapor-deposited layer includes at least one of aluminum oxide and silicon oxide.

15. The laminate according to claim 12, wherein The gas barrier layer is a layer formed of a coating liquid containing a silicon compound and a water-soluble polymer, wherein the silicon compound contains at least one of a first silicon compound and a second silicon compound, wherein the first silicon compound contains at least one of a silicon alkoxide represented by the following general formula (1) and a hydrolyzate thereof, and the second silicon compound contains at least one of a silane coupling agent represented by the following general formula (2) and a hydrolyzate thereof. ， In the general formula (1), OR 1 represents a hydrolyzable group; ， In the general formula (2), OR 3 Represents a hydrolyzable group, R 2 represents a monovalent organic group, and n is an integer of 1 or greater.

16. The laminate according to claim 15, wherein the oxygen permeability thereof at 30°C and 70 RH% is 200 cc / m 2 ·day·atm or less.

17. The laminate according to claim 10, wherein The anchor coating layer includes an organic polymer, and the organic polymer includes at least one of a polyacrylic resin, a polyol resin, a polyurethane resin, a polyamide resin, and a reaction product of these resins.

18. The laminate according to claim 17, wherein The thickness of the anchor coating is 0.01-1 μm.

19. A packaging container formed using the laminate according to claim 8. 20 . A packaged product comprising a packaging container and contents housed in the packaging container, wherein the packaging container is the packaging container according to claim 19 .

Images