Gas barrier laminates, packaging films, packaging containers, and packaging products

Abstract

To provide gas barrier laminates, packaging films, packaging containers, and packaging products that can improve oxygen barrier properties after abuse. [Solution] A gas barrier laminate comprising, in this order, a base layer containing a thermoplastic resin, a metal oxide layer, and a gas barrier coating layer, wherein the ratio of silicon atoms to carbon atoms (Si / C) measured by X-ray photoelectron spectroscopy on the surface of the gas barrier coating layer is greater than 0 and less than 0.50.

Description

[Technical Field]

[0001] This disclosure relates to gas barrier laminates, packaging films, packaging containers, and packaging products. [Background technology]

[0002] In packaging containers such as packaging bags used for food, pharmaceuticals, etc., gas barrier properties are required to prevent the entry of water vapor, oxygen, and other gases that alter the contents, in order to suppress deterioration and spoilage of the contents and maintain their functions and properties. For this reason, gas barrier laminates have conventionally been used in these packaging bags.

[0003] A gas barrier laminate generally comprises a base layer, a metal oxide layer, and a gas barrier coating layer in this order. The gas barrier coating layer is formed by applying a gas barrier coating layer-forming composition, which can impart gas barrier functionality, onto the metal oxide layer and curing it.

[0004] Various types of gas barrier laminates have been developed over the years.

[0005] For example, Patent Document 1 below proposes a transparent laminate in which a transparent primer layer made of a mixture of acrylic resin and isocyanate resin, a thin film layer made of an inorganic compound, and a gas barrier coating layer are sequentially laminated on a substrate made of transparent plastic, wherein the gas barrier coating is a layer formed by applying a coating agent mainly composed of an aqueous polymer and an aqueous solution or water / alcohol mixed solution containing at least one of (a) one or more metal alkoxides and their hydrolysates or (b) tin chloride, and then heating and drying the transparent laminate, thereby improving oxygen barrier properties, etc. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-264292

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, the gas barrier laminate described in Patent Document 1 had the following problems.

[0008] That is, the gas barrier laminate described in Patent Document 1 had room for improvement in terms of improving the oxygen barrier property after abuse.

[0009] An object of the present disclosure is to provide a gas barrier laminate, a packaging film, a packaging container, and a packaging product capable of improving the oxygen barrier property after abuse.

Means for Solving the Problems

[0010] The present disclosure includes a base material layer containing a thermoplastic resin, a metal oxide layer, and a gas barrier coating layer in this order, and on the surface of the gas barrier coating layer, the ratio of silicon atoms to carbon atoms (Si / C) measured by X-ray photoelectron spectroscopy is greater than 0 and less than 0.50, which is a gas barrier laminate. According to the gas barrier laminate of the present disclosure, the oxygen barrier property after abuse can be improved. The reason why such an effect is obtained by the gas barrier laminate of the present disclosure is not clear, but in addition to making the base material layer contain a thermoplastic resin, by setting the ratio of silicon atoms to carbon atoms (Si / C) measured by X-ray photoelectron spectroscopy to be greater than 0 and less than 0.50, it is presumed that the flexibility of the gas barrier coating layer is further improved.

[0011] It is preferable that the gas barrier laminate further includes an anchor coat layer between the base material layer and the metal oxide layer. In this case, the smoothness of the surface of the anchor coat layer is improved compared to the smoothness of the surface of the base material layer. Therefore, the thickness of the metal oxide layer can be made uniform, and the gas barrier property of the gas barrier laminate can be further improved.

[0012] In the above gas barrier laminate, the gas barrier coating layer is composed of a cured product of a composition containing at least one selected from the group consisting of a silicon alkoxide represented by the following general formula (1) and its hydrolyzate, and a water-soluble polymer. In the composition, when the silicon alkoxide is converted to SiO2, the content of the water-soluble polymer in the solid content is preferably 40% by mass or more. Si(OR , 3 , n , 2 )4······(1) (In the general formula (1), R 1 represents an alkyl group or -C2H4OCH3.) In this case, the flexibility of the gas barrier laminate can be further improved. Therefore, the oxygen barrier property of the gas barrier laminate after abuse can be further improved.

[0013] In the above gas barrier laminate, in the composition, when the silicon alkoxide is converted to SiO2, the content of the water-soluble polymer in the solid content is preferably 43% by mass or more and 85% by mass or less. In this case, the oxygen gas barrier property of the gas barrier laminate after abuse can be further improved compared to the case where the content of the water-soluble polymer in the solid content is less than 43% by mass. Also, the interlayer adhesion in the gas barrier laminate after retort treatment can be further improved compared to the case where the content of the water-soluble polymer in the solid content exceeds 85% by mass.

[0014] In the above gas barrier laminate, the gas barrier coating layer preferably further contains a silane coupling agent, and the silane coupling agent preferably contains at least one selected from the group consisting of a silicon compound represented by the following general formula (2) and its hydrolyzate. (R 2 Si(OR 3 )3) n ······(2) (In the general formula (2), R 2 represents a monovalent organic functional group, and R 3(where n represents an alkyl group or -C2H4OCH3, and n represents an integer greater than or equal to 1.) In this case, it becomes possible to improve the adhesion between the gas barrier coating layer and the metal oxide layer, thereby suppressing intralayer delamination in the gas barrier laminate.

[0015] In the above-described gas barrier laminate, it is preferable that the thickness of the metal oxide layer is 5 nm or more and 80 nm or less. In this case, the oxygen barrier properties of the gas barrier laminate are improved compared to when the metal oxide layer thickness is less than 5 nm. Furthermore, the flexibility of the gas barrier laminate is improved compared to when the metal oxide layer thickness exceeds 80 nm, further enhancing the oxygen barrier properties of the gas barrier laminate after abuse. Additionally, the oxygen barrier properties of the gas barrier laminate after retort treatment can also be further improved.

[0016] In the above-described gas barrier laminate, it is preferable that the thickness of the gas barrier coating layer is 50 nm or more and 700 nm or less. In this case, the oxygen barrier properties of the gas barrier laminate are improved compared to when the thickness of the gas barrier coating layer is less than 50 nm. Furthermore, the flexibility of the gas barrier laminate is improved compared to when the thickness of the gas barrier coating layer exceeds 700 nm, further enhancing the oxygen barrier properties of the gas barrier laminate after abuse. Additionally, the oxygen barrier properties of the gas barrier laminate after retort processing can also be further improved.

[0017] In the above-described gas barrier laminate, it is preferable that the thickness of the anchor coat layer is 30 nm or more and 300 nm or less. In this case, compared to when the anchor coat layer thickness is less than 30 nm, it becomes possible to further improve the smoothness of the anchor coat layer surface compared to the substrate layer surface, making it possible to make the thickness of the metal oxide layer more uniform and further improving the oxygen barrier properties. Therefore, the oxygen barrier properties of the gas barrier laminate can be further improved. In addition, compared to when the anchor coat layer thickness exceeds 300 nm, the flexibility of the gas barrier laminate is further improved, and the oxygen gas barrier properties of the gas barrier laminate after abuse can be further improved.

[0018] In the above-described gas barrier laminate, it is preferable that the thickness of the substrate layer is 40 μm or less. In this case, the flexibility of the gas barrier laminate is improved compared to when the thickness of the substrate layer is less than 40 μm, and the oxygen gas barrier properties of the gas barrier laminate after abuse can be further improved.

[0019] Furthermore, this disclosure relates to a packaging film comprising the above-mentioned gas barrier laminate and a sealant layer. Because this packaging film incorporates the gas barrier laminate described above, it can improve oxygen barrier properties after abuse.

[0020] Furthermore, this disclosure relates to a packaging container comprising the above-mentioned packaging film. Because this packaging container is equipped with the above-mentioned packaging film, it can improve oxygen barrier properties after abuse.

[0021] Furthermore, the present disclosure relates to a packaged product comprising the above-mentioned packaging container and contents filled inside the packaging container. This packaged product is equipped with the above-mentioned packaging container, which can improve oxygen barrier properties after abuse, thereby suppressing the deterioration of the contents' quality due to oxygen contamination over a long period of time. [Effects of the Invention]

[0022] According to this disclosure, gas barrier laminates, packaging films, packaging containers, and packaging products are provided that can improve oxygen barrier properties after abuse. [Brief explanation of the drawing]

[0023] [Figure 1] This is a cross-sectional view showing one embodiment of a gas barrier laminate according to the present disclosure. [Figure 2] This is a cross-sectional view showing one embodiment of the packaging film of the present disclosure. [Figure 3] This is a side view showing one embodiment of the packaged product of the present disclosure. [Modes for carrying out the invention]

[0024] The embodiments of this disclosure will be described in detail below.

[0025] <Gas barrier laminate> First, an embodiment of the gas barrier laminate of this disclosure will be described with reference to Figure 1. Figure 1 is a cross-sectional view showing an embodiment of the gas barrier laminate of this disclosure. In Figure 1, the gas barrier laminate 10 comprises, in this order, a base layer 1 containing a thermoplastic resin, a metal oxide layer 3, and a gas barrier coating layer 4. On the surface of the gas barrier coating layer 4, the ratio of silicon atoms to carbon atoms (Si / C), measured by X-ray photoelectron spectroscopy (XPS), is greater than 0 and less than 0.50. The gas barrier laminate 10 may also have an anchor coat layer 2 between the base layer 1 and the metal oxide layer 3.

[0026] This gas barrier laminate 10 can improve oxygen barrier properties after abuse.

[0027] The following describes in detail the base layer 1, anchor coat layer 2, metal oxide layer 3, and gas barrier coating layer 4.

[0028] (base material layer) The base layer 1 is a support layer for the gas barrier coating layer 4 and contains a thermoplastic resin. Examples of thermoplastic resins include polyolefin resins, polyester resins, polyamide resins, polyether resins, acrylic resins, and natural polymer compounds (such as cellulose acetate). These may be used individually or as a mixture of two or more.

[0029] Among these, polyolefin resins or polyester resins are preferred as thermoplastic resins. Examples of polyolefin resins include polyethylene and polypropylene, but from the viewpoint of retort treatment resistance, polypropylene is preferred. Here, polypropylene may be homopolypropylene or propylene copolymer, but from the viewpoint of oxygen barrier properties, it is more preferable that the polypropylene constituting at least the surface layer on the gas barrier coating layer 4 side of the base layer 1 is a polypropylene copolymer. Examples of polyester resins include polyethylene terephthalate resin (PET) and polyethylene naphthalate resin (PEN).

[0030] The base layer 1 may be a stretched film or an unstretched film, but from the viewpoint of oxygen barrier properties, a stretched film is preferred. Here, examples of stretched films include uniaxially oriented films and biaxially oriented films, but a biaxially oriented film is preferred because it improves heat resistance.

[0031] The thickness of the base layer 1 is not particularly limited, but for example, it should be 0.1 mm or less. In particular, the thickness of the base layer 1 is preferably 40 μm or less, more preferably 35 μm or less, and especially preferably 30 μm or less. When the thickness of the base layer 1 is 40 μm or less, the flexibility of the gas barrier laminate 10 is improved compared to when the thickness of the base layer 1 is less than 40 μm, and the oxygen gas barrier properties of the gas barrier laminate 10 after abuse can be further improved. However, from the viewpoint of improving strength, it is preferably 10 μm or more, and more preferably 12 μm or more.

[0032] The base layer 1 may contain additives such as antistatic agents, ultraviolet absorbers, plasticizers, and lubricants, as needed.

[0033] (Anchor coat layer) The anchor coat layer 2 is a layer that further improves the adhesion between the base material layer 1 and the metal oxide layer 3, and is provided between the base material layer 1 and the metal oxide layer 3.

[0034] The material constituting the anchor coat layer 2 is not particularly limited as long as it can improve the adhesion between the substrate layer 1 and the metal oxide layer 3. Such materials include reaction products of organosilane or organometallic compounds, polyol compounds, and isocyanate compounds. In other words, the anchor coat layer 2 can also be called a urethane adhesive layer. The organosilane is, for example, a trifunctional organosilane or a hydrolysate of a trifunctional organosilane. The organometallic compound is, for example, a metal alkoxide or a hydrolysate of a metal alkoxide. The metal elements contained in the organometallic compound are, for example, Al, Ti, Zr, etc. The hydrolysate of the organosilane and the hydrolysate of the metal alkoxide each only need to have at least one hydroxyl group. From the viewpoint of transparency, the polyol compound is preferably an acrylic polyol. The isocyanate compound mainly functions as a crosslinking agent or a curing agent. The polyol compound and the isocyanate compound may be monomers or polymers.

[0035] The thickness of the anchor coat layer 2 is not particularly limited as long as it can improve the adhesion between the base material layer 1 and the metal oxide layer 3, but it is preferably 30 nm or more. In this case, compared with the case where the thickness of the anchor coat layer 2 is less than 30 nm, the smoothness of the surface of the anchor coat layer 2 can be further improved compared to the surface of the base material layer 1, the thickness of the metal oxide layer 3 can be made more uniform, and the oxygen barrier property can also be further improved. Therefore, the oxygen barrier property of the gas barrier laminate 10 can be further improved. The thickness of the anchor coat layer 2 is more preferably 40 nm or more, and even more preferably 50 nm or more. By increasing the thickness of the anchor coat layer 2, it is possible to further suppress the decrease in the water vapor barrier property when an external force such as stretching is applied. The thickness of the anchor coat layer 2 is preferably 300 nm or less. In this case, compared with the case where the thickness of the anchor coat layer 2 is 300 nm or more, the flexibility of the gas barrier laminate 10 is further improved, and the oxygen gas barrier property of the gas barrier laminate 10 after abuse can be further improved. The thickness of the anchor coat layer 2 is more preferably 200 μm or less.

[0036] (Metal oxide layer) The metal oxide layer 3 is a layer containing a metal oxide. The gas barrier laminate 10 can have the metal oxide layer 3, whereby the gas barrier property can be further improved.

[0037] Examples of the metal constituting the metal oxide include at least one atom selected from the group consisting of Si, Al, Mg, Sn, Ti, and In.From the viewpoint of water vapor barrier property, the metal oxide is preferably SiO x or AlO x Among them, as the metal oxide, SiO x is preferred. In this case, the gas barrier laminate 10 can have a more excellent water vapor barrier property. The metal oxide layer 3 may be composed of a single layer or a plurality of layers.

[0038] The thickness of the metal oxide layer 3 is not particularly limited, but it is preferably 5 nm or more. In this case, the oxygen barrier properties of the gas barrier laminate 10 are improved compared to when the thickness of the metal oxide layer 3 is less than 5 nm. The thickness of the metal oxide layer 3 is more preferably 8 nm or more, and particularly preferably 10 nm or more. Furthermore, the thickness of the metal oxide layer 3 is preferably 80 nm or less. In this case, the flexibility of the gas barrier laminate 10 is further improved compared to when the thickness of the metal oxide layer 3 exceeds 80 nm, and the oxygen barrier properties of the gas barrier laminate 10 after abuse can be further improved. It is also possible to further improve the oxygen barrier properties of the gas barrier laminate 10 after retort treatment. The thickness of the metal oxide layer 3 is more preferably 70 nm or less, and particularly preferably 60 nm or less.

[0039] (Gas barrier coating layer) The gas barrier coating layer 4 is composed of a cured body of a gas barrier coating layer forming composition. On the surface of the gas barrier coating layer 4, the ratio of silicon atoms to carbon atoms (hereinafter also referred to as "Si / C"), measured by X-ray photoelectron spectroscopy (hereinafter also referred to as "XPS"), is greater than 0 and less than 0.50. In this case, the oxygen barrier properties of the gas barrier laminate 10 after abuse can be improved compared to the case where Si / C is 0.50 or greater.

[0040] The Si / C ratio obtained by XPS is determined by performing narrow-field analysis using the following measuring instruments under the following measurement conditions to acquire a spectrum, and then calculating the Si to C ratio from this spectrum. Note that the ratio of silicon atoms to carbon atoms (Si / C) is expressed as a molar ratio. <Measuring equipment> JEOL Ltd. JPS-9030 Photoelectron Spectrometer <Measurement conditions> (Spectrum sampling conditions) Incident X-ray: MgKα (monochromatic X-ray, hν=1253.6eV) X-ray output: 10W (10kV 10mA) X-ray scanning area (measurement area): Circular area with a diameter of 6 mm Photoelectron capture angle: 90°

[0041] The Si / C ratio determined by XPS is preferably 0.48 or less, and more preferably 0.45 or less. While the Si / C ratio determined by XPS can be greater than 0, from the viewpoint of improving adhesion to the metal oxide layer 3 after retort treatment, it is preferable that the Si / C ratio determined by XPS is 0.15 or more.

[0042] The gas barrier coating layer forming composition comprises at least one selected from the group consisting of silicon alkoxides and their hydrolysates, and a water-soluble polymer. Silicon alkoxides are given by the following general formula (1)Si(OR 1 ) is represented by 4. Si(OR 1 )4······(1) In general formula (1), R 1 The group represents an alkyl group or -C2H4OCH3. Examples of alkyl groups include methyl and ethyl groups. Among these, the ethyl group is preferred. In this case, the silicon alkoxide becomes a tetraethoxysilane, which can be relatively stabilized in aqueous solvents after hydrolysis.

[0043] Examples of water-soluble polymers include polyvinyl alcohol resin, its modified form, and polyacrylic acid. These can be used individually or in combination of two or more. Among these, polyvinyl alcohol resin or its modified form is preferred as the water-soluble polymer. In this case, the composition can impart superior gas barrier properties to the gas barrier laminate 10 upon curing. Furthermore, even after curing, the composition can impart superior flexibility to the gas barrier laminate 10, thereby further improving oxygen barrier properties after abuse.

[0044] When the water-soluble polymer is composed of a polyvinyl alcohol resin or a modified version thereof, the degree of saponification of the water-soluble polymer is not particularly limited, but from the viewpoint of improving the gas barrier properties of the gas barrier laminate 10, it is preferably 95% or more, and may be 100%.

[0045] The degree of polymerization of the water-soluble polymer is not particularly limited, but from the viewpoint of improving the gas barrier properties of the gas barrier laminate 10, it is preferably 300 or higher. The degree of polymerization of the water-soluble polymer is preferably 450 to 2400.

[0046] The content of water-soluble polymers in the solid content is not particularly limited, but when silicon alkoxide is converted to SiO2, it is preferably 40% by mass or more. In this case, the flexibility of the gas barrier laminate 10 can be further improved. Therefore, the oxygen barrier properties of the gas barrier laminate 10 after abuse can be further improved.

[0047] The content of water-soluble polymers in the solid content is preferably 43% by mass or more, more preferably 44% by mass or more, and particularly preferably 45% by mass or more. When the content of water-soluble polymers in the solid content is 43% by mass or more, the oxygen gas barrier properties of the gas barrier laminate after abuse can be further improved compared to when the content of water-soluble polymers in the solid content is less than 43% by mass.

[0048] The content of water-soluble polymers in the solid content may be less than 100% by mass, but it is preferably 85% by mass or less, and more preferably 75% by mass or less. When the content of water-soluble polymers in the solid content is 85% by mass or less, the interlayer adhesion in the gas barrier laminate 10 after retort treatment can be further improved compared to when the content of water-soluble polymers in the solid content exceeds 85% by mass.

[0049] The gas barrier coating layer forming composition may further contain a silane coupling agent as a curing agent.

[0050] The silane coupling agent is not particularly limited, but it is preferably at least one selected from the group consisting of silicon compounds represented by the following general formula (2) and their hydrolysates. (R 2 Si(OR 3 )3) n ...(2) In the above general formula (2), R 2 represents a monovalent organic functional group, R 3 This represents an alkyl group or -C2H4OCH3. In this case, it becomes possible to improve the adhesion between the gas barrier coating layer 4 and the metal oxide layer 3, thereby suppressing delamination in the gas barrier laminate 10. Note, R 2 and R 3 They may be the same or different from each other. 3 The elements may be identical or different from one another. R 2 Examples of monovalent organic functional groups include vinyl groups, epoxy groups, mercapto groups, amino groups, or monovalent organic functional groups containing isocyanate groups. Among these, isocyanate groups are preferred as monovalent organic functional groups. In this case, the composition can have better hot water resistance after curing, and it is possible to impart greater laminate strength to the gas barrier laminate 10 even after retort treatment. R 3 Examples of alkyl groups represented by include methyl groups and ethyl groups. Among these, methyl groups are preferred. In this case, hydrolysis occurs quickly. n represents an integer greater than or equal to 1. When n is 1, the silane coupling agent represents a monomer, while when n is 2 or greater, the silane coupling agent represents a polymer. It is preferable that n is 3. In this case, the hot water resistance of the gas barrier coating layer 4 can be further improved, and greater laminate strength can be imparted to the gas barrier laminate 10 even after retort treatment.

[0051] Examples of silane coupling agents include vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylethyldiethoxysilane; mercapto group-containing silane coupling agents such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; and isocyanate group-containing silane coupling agents such as 3-isocyanatetopropyltriethoxysilane and 1,3,5-tris(3-methoxysilylpropyl)isocyanurate. These silane coupling agents may be used individually or in combination of two or more types.

[0052] The content of the silane coupling agent in the solid content is not particularly limited, but is preferably 3% by mass or more, more preferably 5% by mass or more, and particularly preferably 7% by mass or more. In this case, compared to the case where the content of the silane coupling agent in the solid content is less than 3% by mass, curing can impart greater laminate strength to the gas barrier laminate 10 even after retort treatment. The content of the silane coupling agent in the solid content is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 12% by mass or less. In this case, compared to when the content of the silane coupling agent in the solid content exceeds 20% by mass, the silane coupling agent is less likely to bleed out, and surface contamination is suppressed. Furthermore, the content of the silane coupling agent in the solid content is, for example, if the silane coupling agent is represented by the general formula (2) above, the mass of the silane coupling agent is R 2 The calculation is performed by converting it to the mass of Si(OH)3.

[0053] (Other components in the solid content) The solid content may further contain known additives such as dispersants, stabilizers, viscosity modifiers, and colorants, as needed, to the extent that they do not impair the gas barrier properties of the gas barrier coating layer 4.

[0054] (Total content of components in solid matter) The total content of silicon alkoxide or its hydrolysate, water-soluble polymer, and silane coupling agent in the solid content is not particularly limited, but is usually 95% by mass or more, preferably 97% by mass or more, and may be 100% by mass.

[0055] (liquid) Typically, an aqueous medium is used as the liquid to dissolve or disperse the above-mentioned solid components. Examples of aqueous mediums include water, hydrophilic organic solvents, or mixtures thereof. Examples of hydrophilic organic solvents include alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; cellosolves; carbitols; and nitriles such as acetonitrile. These can be used individually or in combination of two or more.

[0056] As the aqueous medium, an aqueous medium consisting solely of water, or an aqueous medium containing water as the main component, is preferred. When the aqueous medium contains water as the main component, the water content in the aqueous medium is preferably 70% by mass or more, and more preferably 80% by mass or more.

[0057] The thickness of the gas barrier coating layer 4 is not particularly limited, but it is preferably 50 nm or more. In this case, the oxygen barrier properties of the gas barrier laminate 10 are improved compared to the case where the thickness of the gas barrier coating layer 4 is less than 50 nm.

[0058] From the viewpoint of improving gas barrier properties, the thickness of the gas barrier coating layer 4 is more preferably 100 nm or more, and particularly preferably 200 nm or more. On the other hand, the thickness of the gas barrier coating layer 4 is preferably 700 nm or less. Compared to the case where the thickness of the gas barrier coating layer 4 exceeds 700 nm, the flexibility of the gas barrier laminate 10 is further improved, and the oxygen barrier properties of the gas barrier laminate 10 after abuse can be further improved. Furthermore, the oxygen barrier properties of the gas barrier laminate 10 after retort treatment can also be further improved.

[0059] From the viewpoint of further improving the flexibility of the gas barrier coating layer 4, the thickness of the gas barrier coating layer 4 is more preferably 500 nm or less, and particularly preferably 400 nm or less.

[0060] <Method for manufacturing gas barrier laminates> Next, a method for manufacturing the gas barrier laminate 10 will be described.

[0061] First, prepare the base layer 1.

[0062] Next, an anchor coat layer 2 is formed on one surface of the base material layer 1. Specifically, the anchor coat layer 2 is formed by applying an anchor coat layer forming composition onto one surface of the base layer 1, heating it, and drying it. At this time, the heating temperature is, for example, 50 to 200°C, and the drying time is, for example, about 10 seconds to 10 minutes.

[0063] Next, a metal oxide layer 3 is formed on top of the anchor coat layer 2. The metal oxide layer 3 can be formed, for example, by a vacuum deposition method. Examples of vacuum deposition methods include physical vapor deposition and chemical vapor deposition. Examples of physical vapor deposition methods include vacuum evaporation, sputtering evaporation, and ion plating. Vacuum evaporation is particularly preferred among physical vapor deposition methods. Examples of vacuum evaporation methods include resistance heating vacuum evaporation, EB (Electron Beam) heating vacuum evaporation, and induction heating vacuum evaporation. Examples of chemical vapor deposition methods include thermal CVD, plasma CVD, and photoCVD.

[0064] Next, a gas barrier coating layer 4 is formed on the metal oxide layer 3.

[0065] The gas barrier coating layer 4 can be formed, for example, by applying a gas barrier coating layer forming composition onto the metal oxide layer 3 and curing it. Here, curing of the solid component means that the silicon alkoxide or its hydrolysate and water-soluble polymer in the solid component, or the silicon alkoxide or its hydrolysate, water-soluble polymer and silane coupling agent react with each other and become integrated.

[0066] Known methods can be used to apply the gas barrier coating layer composition. Specifically, examples of application methods include wet film formation methods such as gravure coating, dip coating, reverse coating, wire bar coating, and die coating.

[0067] Hardening can be achieved, for example, by heating.

[0068] When curing is performed by heating, the heating temperature and heating time should be set so that the solid components in the gas barrier coating layer forming composition and the liquid such as an aqueous medium can be cured simultaneously. For example, the heating temperature can be 80 to 250°C, and the heating time can be 3 seconds to 10 minutes.

[0069] As described above, a gas barrier laminate 10 is obtained.

[0070] <Packaging film> Next, embodiments of the packaging film of this disclosure will be described with reference to Figure 2. In Figure 2, the same reference numerals are used for components that are the same as those in Figure 1, and redundant explanations are omitted.

[0071] Figure 2 is a cross-sectional view showing one embodiment of the packaging film of the present disclosure. As shown in Figure 2, the packaging film 20 comprises a gas barrier laminate 10 and a sealant layer 21 laminated on the gas barrier laminate 10, wherein the sealant layer 21 is located on the gas barrier coating layer 4 side of the base layer 1 of the gas barrier laminate 10. As shown in Figure 2, in the gas barrier laminate 10, the gas barrier coating layer 4 and the sealant layer 21 may be bonded together by an adhesive layer 22.

[0072] Since this packaging film 20 is equipped with the gas barrier laminate 10 described above, it can improve oxygen barrier properties after abuse.

[0073] For example, the adhesive layer 22 can be made from a polyester-isocyanate resin, a urethane resin, or a polyether resin. For use of the packaging film 20 in retort applications, a two-component curing urethane adhesive with retort resistance is preferably used.

[0074] (Sealant layer) Examples of materials for the sealant layer 21 include thermoplastic resins such as polyolefin resins and polyester resins, but polyolefin resins are generally used. Specifically, as polyolefin resins, ethylene-based resins such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer, as well as polypropylene-based resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer, or mixtures thereof can be used. The material for the sealant layer 21 can be appropriately selected from the above-mentioned thermoplastic resins depending on the intended use and temperature conditions such as boiling or retorting.

[0075] The thermoplastic resin constituting the sealant layer 21 may be stretched or not, but from the viewpoint of lowering the melting point and facilitating heat sealing, it is preferable that it be not stretched.

[0076] The thickness of the sealant layer 21 is determined appropriately based on the mass of the contents, the shape of the packaging bag, etc., and is not particularly limited, but from the viewpoint of the flexibility and adhesion of the packaging film 20, it is preferably 30 to 150 μm.

[0077] <Packaging products> Next, embodiments of the packaging product of this disclosure will be described with reference to Figure 3. Figure 3 is a side view showing one embodiment of the packaging product of this disclosure. In Figure 3, the same reference numerals are used for components that are the same as those in Figure 1 or Figure 2, and redundant explanations are omitted. As shown in Figure 3, the packaged product 40 comprises a packaging container 30 and contents C filled inside the packaging container 30. The packaging container 30 shown in Figure 3 is obtained by using a pair of packaging films 20 and heat-sealing the peripheral edges of the packaging films 20 with the sealant layers 21 facing each other. Note that in Figure 3, the adhesive layer 22 of the packaging film 20 is omitted.

[0078] This packaged product 40 is equipped with a packaging container 30, and the packaging container 30 can improve oxygen barrier properties after abuse, thereby suppressing the deterioration of the quality of the contents C due to oxygen contamination over a long period of time.

[0079] The packaging container 30 can also be obtained by folding a single packaging film 20 and heat-sealing the peripheral edge of the packaging film 20 with the sealant layers 21 facing each other.

[0080] Examples of packaging containers 30 include packaging bags, laminated tube containers, and liquid paper containers.

[0081] Contents C are not particularly limited and may include food, liquids, pharmaceuticals, electronic components, etc.

[0082] This disclosure is not limited to the embodiments described above. For example, in the above embodiments, the sealant layer 21 is located on the gas barrier coating layer 4 side of the base layer 1 of the gas barrier laminate 10 in the packaging film 20, but the sealant layer 21 may be located on the opposite side of the base layer 1 from the gas barrier coating layer 4. [Examples]

[0083] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0084] <Preparation of coating solution> Coating solutions 1 to 8, which are gas barrier coating layer forming compositions used in the examples or comparative examples, were prepared as follows.

[0085] (Coating solution 1) Tetraethoxysilane (trade name: KBE04, solids content: 100%, manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter also referred to as "TEOS") as a silicon alkoxide, methanol (Kanto Chemical Co., Ltd.), and 0.1N hydrochloric acid (manufactured by Kanto Chemical Co., Ltd.) were mixed in a mass ratio of 45 / 15 / 40 to obtain a hydrolyzed solution (hydrolyzed TEOS solution), which was then mixed with a 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") to obtain coating solution 1. Coating solution 1 was prepared so that the mass ratio of TEOS (SiO2 equivalent) to PVA was 40 / 60 when the solids content was set to 100.

[0086] (Coating solution 2) A hydrolysis solution of TEOS, a 5% by mass aqueous solution of PVA, and 1,3,5-tris(3-methoxysilylpropyl) isocyanurate as a silane coupling agent (SC agent) are mixed in a water / IPA = 1 / 1 mass ratio, resulting in a solid content of 5% (by mass ratio, R 2Coating solution 2 was obtained by mixing a solution that had been diluted and adjusted to the ratio of Si(OH)3 to obtain coating solution 2. Coating solution 2, when the solid content is set to 100, consists of TEOS (SiO2 equivalent value) and isocyanurate silane (R 2 The mixture was prepared so that the mass ratio of Si(OH)3 (converted to Si(OH)3) to PVA was 40 / 5 / 55.

[0087] (Coating solution 3-8) When the solid content is set to 100, TEOS (SiO2 equivalent value) and isocyanurate silane (R 2 Coating solutions 3 to 8 were prepared in the same manner as coating solution 2, except that the mass ratio of Si(OH)3 (converted value) to PVA was as shown in Table 1 or Table 2.

[0088] <Preparation of composition for forming anchor coat layer> The anchor coat layer forming composition was prepared as follows. An acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups in the tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate to a solid content (total amount of acrylic polyol and tolylene diisocyanate) of 5% by mass. To the diluted mixture, β-(3,4-epoxycyclohexyl)trimethoxysilane was added in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare an anchor coat layer forming composition (anchor coat agent).

[0089] <Fabrication of gas barrier laminates> (Example 1) A gas barrier laminate was fabricated using a roll-to-roll method as follows. First, a polyethylene terephthalate film (product name "P60", manufactured by Toray Industries, Inc.) with a thickness of 12 μm was mounted on an unwinding device, a conveying device, and a winding device.

[0090] Next, the substrate layer is fed out, and AlO is poured onto the substrate layer in transit so that the film thickness is 12 nm. xA film (metal oxide layer) was formed. At this time, AlO x The film is formed using an electron beam heating vacuum deposition apparatus, where an aluminum ingot is evaporated by electron beam heating while the pressure is 1.2 × 10⁻⁶ -2 This was done by introducing oxygen to achieve a pressure of Pa.

[0091] This AlO x Coating solution 1 was applied to the film and heated and dried to form a gas barrier coating layer with a thickness of 350 nm, as shown in Table 1. During heating, the TEOS and PVA constituting the solid components of coating solution 1 were cured to form a cured body, while the liquid in coating solution 1 was removed. Specifically, the heating temperature was 90°C.

[0092] As described above, a gas barrier laminate was obtained in which a base layer, a metal oxide layer, and a gas barrier coating layer were laminated in this order.

[0093] The ratio of carbon atoms to silicon atoms (Si / C) of the gas barrier laminate obtained in this way was determined by XPS as follows. Specifically, the Si / C ratio obtained by XPS was determined by performing narrow-field analysis using the following measuring instruments under the following measurement conditions to acquire a spectrum, and then calculating the ratio (molar ratio) of Si to C from this spectrum. The results are shown in Table 1. <Measuring equipment> JEOL Ltd. JPS-9030 Photoelectron Spectrometer <Measurement conditions> (Spectrum sampling conditions) Incident X-ray: MgKα (monochromatic X-ray, hν=1253.6eV) X-ray output: 10W (10kV 10mA) X-ray scanning area (measurement area): Circular area with a diameter of 6 mm Photoelectron capture angle: 90°

[0094] (Example 2) A gas barrier laminate was fabricated using a roll-to-roll method as follows. First, a polyethylene terephthalate film (product name "P60", manufactured by Toray Industries, Inc.) with a thickness of 12 μm was mounted on an unwinding device, a conveying device, and a winding device.

[0095] Next, the anchor coat layer-forming composition prepared as described above was applied to one surface of the substrate layer during transport by gravure coating to form a coating film. The coating film was then heated at 120°C for 10 seconds and dried to form an anchor coat layer with a thickness of 25 nm, and a laminate was obtained. The resulting laminate was then wound up with a winding device to obtain a roll-shaped laminate.

[0096] Next, the roll-shaped laminate was mounted on the unwinding device, conveying device, and winding device. Then, the laminate was unwound from the roll-shaped laminate, and AlO was applied to the anchor coat layer of the laminate as it was being conveyed, so that the thickness was 12 nm. x A film (metal oxide layer) was formed. At this time, AlO x The film is formed using an electron beam heating vacuum deposition apparatus, where an aluminum ingot is evaporated by electron beam heating while the pressure is 1.2 × 10⁻⁶ -2 This was done by introducing oxygen to achieve a pressure of Pa.

[0097] This AlO x Coating solution 2 was applied to the film and heated and dried to form a gas barrier coating layer with a thickness of 350 nm, as shown in Table 1. During heating, the liquid in coating solution 2 was removed while the solid components TEOS, PVA, and isocyanurate silane in coating solution 2 hardened to form a cured body. Specifically, the heating temperature was 90°C.

[0098] As described above, a gas barrier laminate was obtained in which a base layer, an anchor coat layer, a metal oxide layer, and a gas barrier coating layer were laminated in this order.

[0099] The Si / C ratio of the gas barrier laminate obtained in this manner was determined by XPS in the same manner as in Example 1. The results are shown in Table 1.

[0100] (Examples 3-27 and Comparative Examples 1-5) A gas barrier laminate was fabricated in the same manner as in Example 2, except that the composition of the base layer, anchor coat layer, metal oxide layer, and gas barrier coating layer was as shown in Table 1 or Table 2. When the metal oxide layer was composed of SiOx, silicon dioxide was used as the SiO deposition material instead of the aluminum ingot evaporated by electron beam heating. In Table 1 or Table 2, "OPP" used for the base layer refers to a 25 μm thick polypropylene resin film (product name "U-1", biaxially oriented film, manufactured by Mitsui Chemicals Tohcello, Inc.).

[0101] The Si / C ratio of the gas barrier laminate obtained in this manner was determined by XPS in the same manner as in Example 1. The results are shown in Table 1 or Table 2.

[0102] <Evaluation of gas barrier laminates> The gas barrier laminates obtained in Examples 1-27 and Comparative Examples 1-5 were evaluated for their oxygen barrier properties after XPS ablation and after retort treatment, as described below. (1) Preparation of laminating film First, in order to perform the above evaluation, a laminate film was prepared as follows.

[0103] Specifically, a laminate film with a surface width of 210 mm was prepared by attaching a 60 μm thick unstretched polypropylene film (CPP, product name "Trefan ZK207", manufactured by Toray Film Processing Co., Ltd.) to the surface of the substrate layer of the gas barrier laminate obtained in Examples 1 to 27 and Comparative Examples 1 to 5 using a two-component adhesive (product name "Takelac A-525 / Takenate A-52", manufactured by Mitsui Chemicals, Inc.).

[0104] (2) Measurement of oxygen permeability Using an oxygen permeability measuring device (product name "OX-TRAN2 / 20", manufactured by MOCON), the oxygen permeability (unit: cc / m³) of the above laminate film was measured under conditions of a temperature of 30°C and a relative humidity of 70%. 2 The initial oxygen permeability was measured using (day·atm). The measurement was performed in accordance with JIS K-7126-2. The results are shown in Tables 1 and 2.

[0105] (3) Oxygen barrier properties after abuse The above laminate film was subjected to abuse by performing a bending test (gelboflex test) and a stretching test as described below, and the oxygen permeability after abuse was measured in the same manner as the initial oxygen permeability measurement described above. The results are shown in Tables 1 and 2.

[0106] (Bending test) The bending test was performed as follows: A test sample A measuring 297 mm in length and 210 mm in width was cut from the laminate film mentioned above. This test sample A was attached to the fixed head of a Gelboflex tester (manufactured by Tester Sangyo Co., Ltd.) to form a cylindrical body with a diameter of 87.5 mm and a width of 210 mm, thereby creating a cylindrical body. Then, holding both ends of the cylindrical body, the initial gripping distance was set to 175 mm and the stroke to 87.5 mm, and a reciprocating motion of twisting 440 degrees was repeatedly performed at a speed of 40 times / minute for 10 repetitions, thereby bending the cylindrical body.

[0107] (Stretch test) The stretching test was conducted as follows: From the laminate film mentioned above, a test sample B measuring 200 mm in length and 150 mm in width was cut out. Using a Tensilon machine manufactured by Toyo Baldwin, the sample was stretched 5% in the lengthwise direction at a speed of 100 μm / second. After holding this state for 1 minute, the test sample B was returned to its original position at the same speed. The criteria for determining whether oxygen barrier function after abuse is acceptable are as follows. (Pass / Fail Criteria) Passed... Oxygen permeability after bending is 15 cc / m³ 2 • day·atm is less than and The oxygen permeability after stretching is 2 cc / m 2 • day·atm is less than or equal to Failed... Oxygen permeability after bending was 15 cc / m³ 2 • Day • ATM is larger than The oxygen permeability after stretching is 2 cc / m 2 • day • ATM is larger or Satisfying both

[0108] (4) Oxygen barrier properties after retort processing (Preparation of test samples) To evaluate the oxygen barrier properties after retort processing, test sample C was prepared as follows. First, a three-sided pouch with an opening was prepared using the laminate film manufactured as described above. The three-sided pouch was formed by folding the laminate film so that two unstretched polypropylene films faced each other, and then heat-sealing the two unstretched polypropylene films together. Then, tap water (city water) was injected through the opening to seal the opening of the three-sided pouch, and a sealed body was prepared, which was designated as test sample C. (Retort processing) The test sample C obtained as described above was subjected to heat treatment (retort treatment) at 121°C for 30 minutes. The oxygen permeability after retort treatment was then measured in the same manner as the initial oxygen permeability measurement described above. The results are shown in Tables 1 and 2. [Table 1] [Table 2]

[0109] As shown in Tables 1 and 2, the gas barrier laminates of Examples 1 to 27 showed significantly lower oxygen permeability after abuse compared to the gas barrier laminates of Comparative Examples 1 to 5.

[0110] Based on the above, it has been confirmed that the gas barrier laminate of this disclosure can improve oxygen barrier properties after abuse. [Explanation of Symbols]

[0111] 1...Base layer, 3...Metal oxide layer, 4...Gas barrier coating layer, 10...Gas barrier laminate, 20...Packaging film, 21...Sealant layer, 30...Packaging container, 40...Packaged product.

Claims

1. The material comprises a base layer containing a thermoplastic resin, a metal oxide layer, and a gas barrier coating layer in this order. The aforementioned gas barrier coating layer A cured body of a composition comprising at least one selected from the group consisting of silicon alkoxides represented by the following general formula (1) and their hydrolysates, a water-soluble polymer, and a silane coupling agent, or a cured body of a composition comprising at least one selected from the group consisting of silicon alkoxides represented by the following general formula (1) and their hydrolysates, and a water-soluble polymer. In the above composition, the silicon alkoxide is SiO ２ When converted to this, the content of the water-soluble polymer in the solid content is 43% by mass or more and 55% by mass or less. A gas barrier laminate in which the ratio of silicon atoms to carbon atoms (Si / C) measured by X-ray photoelectron spectroscopy on the surface of the gas barrier coating layer is greater than 0 and less than 0.

50. Si(OR １ ) ４ ・・・・・・(1) (In the above general formula (1), R １ is an alkyl group, or -C ２ H ４ OCH ３ (This represents...)

2. The gas barrier laminate according to claim 1, further comprising an anchor coat layer between the substrate layer and the metal oxide layer.

3. The gas barrier laminate according to claim 1 or 2, wherein the silane coupling agent comprises at least one selected from the group consisting of silicon compounds represented by the following general formula (2) and hydrolysates thereof. (R ２ Si(OR ３ ) ３ ) ｎ ・・・・・・(2) (In the above general formula (2), R ２ represents a monovalent organic functional group, R ３ is an alkyl group, or -C ２ H ４ OCH ３ This represents n, where n is an integer greater than or equal to 1.

4. The gas barrier laminate according to any one of claims 1 to 3, wherein the thickness of the metal oxide layer is 5 nm or more and 80 nm or less.

5. The gas barrier laminate according to any one of claims 1 to 4, wherein the thickness of the gas barrier coating layer is 50 nm or more and 700 nm or less.

6. The gas barrier laminate according to claim 2, wherein the thickness of the anchor coat layer is 30 nm or more and 300 nm or less.

7. The gas barrier laminate according to any one of claims 1 to 6, wherein the thickness of the substrate layer is 40 μm or less.

8. A packaging film comprising a gas barrier laminate according to any one of claims 1 to 7 and a sealant layer.

9. A packaging container comprising the packaging film described in claim 8.

10. A packaged product comprising a packaging container according to claim 9 and contents filled inside the packaging container.

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