Multilayer structures and packaging materials containing them

Abstract

Provided is a multilayer structure in which a vapor-deposited film (X) including a vinyl alcohol-based polymer layer (A) and a vapor-deposited layer (B) made of silicon oxide or a metal oxide, and a polyolefin layer (C) are laminated, wherein when the vinyl alcohol-based polymer layer (A)-side surface of the vapor-deposited layer (B) is referred to as surface (b1) and the reverse surface of the vapor-deposited layer (B) is referred to as surface (b2), the ratio [(O / M)b1 / (O / M)c] of the molar ratio (O / M)b1 of oxygen element (O) to silicon element or metal element (M) in surface (b1) to the molar ratio (O / M)c of oxygen element (O) to silicon element or metal element (M) at a position equidistant from surface (b1) and surface (b2) is 1.1-1.7 as determined from an elemental analysis performed for the vapor-deposited layer (B) in the depth direction from surface (b2) to surface (b1) by a scanning X-ray photoelectron spectroscopic analyzer, and the proportion in thickness of the polyolefin layer is 75% or more. Accordingly, a multilayer structure containing a vapor-deposited film having excellent gas barrier properties and flex resistance is provided.

Description

[Technical Field]

[0001] The present invention relates to a multilayer structure comprising a vapor-deposited film containing a vinyl alcohol-based polymer layer and a vapor-deposited layer. The present invention also relates to a packaging material comprising the multilayer structure. Furthermore, the present invention relates to a package containing contents within the packaging material. The present invention also relates to a recovery composition comprising the recovered material of the multilayer structure. Furthermore, the present invention relates to a method for recovering the multilayer structure. [Background technology]

[0002] Packaging materials for long-term food preservation often require gas barrier properties, including oxygen barrier properties. Using packaging materials with high gas barrier properties can suppress oxidative deterioration of food due to oxygen penetration and the growth of microorganisms. As inorganic layers that improve gas barrier properties, metal foils such as aluminum, metal vapor-deposited layers, and inorganic oxide vapor-deposited layers such as silicon dioxide and aluminum oxide are widely used (Patent Document 1).

[0003] On the one hand, in recent years, due to environmental problems and waste problems, the demand for so-called post-consumer recycling (hereinafter sometimes simply abbreviated as recycling), which involves collecting and recycling packaging materials consumed in the market, has been increasing globally. In recycling, a process is generally adopted in which the collected packaging materials are cut, sorted and washed as necessary, and then melt-mixed using an extruder. In this regard, it is required that the packaging material be composed of a single material as much as possible (monomaterialization), so that high-purity and high-quality recycled raw materials can be obtained. In particular, aluminum foil and polyester film are known to inhibit recyclability because of their poor compatibility and dispersibility with polyolefin-based resins widely used as packaging materials. Instead of a multilayer structure including an inorganic vapor deposition film having an aluminum foil or polyester film substrate, a multilayer structure including an inorganic vapor deposition film having a substrate containing a polyolefin-based resin is required. For example, in Patent Document 2, an inorganic vapor deposition layer is laminated on the surface of the EVOH layer of a polyethylene-based multilayer film with the EVOH layer as the outermost layer, and a vapor deposition multilayer film that achieves both gas barrier properties and recyclability has also been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in order to achieve monomaterialization, when using packaging materials made of the above-mentioned conventional multilayer films, particularly vapor-deposited multilayer films in which an inorganic vapor-deposited layer is laminated on the surface of the EVOH layer of a polyolefin-based multilayer film where the EVOH layer is the outermost layer, it was found that the gas barrier properties deteriorate when subjected to bending or when stored for a certain period of time or longer with contents containing a specific amount of moisture or oil.

[0006] In view of these circumstances, an object of the present invention is to provide a multilayer structure, a packaging material, and a packaging body using the same, which can suppress the deterioration of gas barrier properties in a vapor-deposited film having an inorganic layer on the surface of a vinyl alcohol polymer layer, even when it is subjected to bending or when it is stored for a certain period of time or longer with contents containing a specific amount of moisture or oil packaged inside. Another object of the present invention is to provide a recovery composition including the recovered material of the multilayer structure and a method for recovering the multilayer structure. [Means for solving the problem]

[0007] The inventors of the present invention have conducted extensive research to achieve the above objectives and have found that it is possible to (1) use a vinyl alcohol-based polymer layer as the substrate for forming the vapor-deposited layer, (2) form a vapor-deposited layer made of silicon dioxide or a metal oxide, and (3) appropriately segregate the oxygen element in the vapor-deposited layer by blowing in an appropriate amount of oxygen gas when forming the vapor-deposited layer. As a result, they have found that a multilayer structure with excellent gas barrier properties, flexibility, and storage stability when packaging contents containing specific amounts of moisture, oil, etc. can be obtained, and have completed the present invention.

[0008] In other words, the present invention is as follows. [1] A multilayer structure comprising a vinyl alcohol polymer layer (A), a vapor-deposited film (X) containing a vapor-deposited layer (B) made of silicon dioxide or a metal oxide, and a polyolefin layer (C), A vapor-deposited layer (B) with a thickness of 30 nm to 200 nm is directly formed on the surface of a vinyl alcohol-based polymer layer (A). When elemental analysis of the deposited layer (B) is performed in the depth direction from surface (b2) to surface (b2) using a scanning X-ray photoelectron spectroscopy analyzer, with the side of the deposited layer (B) facing the vinyl alcohol polymer layer (A) designated as surface (b1) and the opposite side of the deposited layer (B) designated as surface (b2), the molar ratio (O / M) of oxygen element (O) to silicon element or metal element (M) on surface (b1) is determined. b1 And the molar ratio (O / M) of oxygen element to silicon element or metal element (M) at positions equidistant from plane (b1) and plane (b2). c The ratio [(O / M)] b1 / (O / M) c ] is between 1.1 and 1.7, The thickness of the vinyl alcohol polymer layer (A) is 0.1 μm or more and less than 20 μm, and A multilayer structure in which the ratio of the thickness of the layer mainly composed of polyolefin to the total thickness of the multilayer structure is 75% or more. [2] The multilayer structure according to [1], wherein the vapor-deposited layer (B) is made of silicon oxide or aluminum oxide. [3] The multilayer structure according to [2], wherein the vapor-deposited layer (B) is made of silicon dioxide. [4] The molar ratio (O / M) b1 A multilayer structure as described in any one of [1] to [3], wherein the ratio is between 1.85 and 2.35. [5] The molar ratio (O / M) c A multilayer structure described in any one of items [1] to [4], wherein the ratio is between 1.5 and 2.0. [6] A multilayer structure according to any one of [1] to [5], wherein the vapor-deposited film (X) comprises a polyolefin substrate layer (G), a polyolefin adhesive layer (H), a vinyl alcohol polymer layer (A), and a vapor-deposited layer (B) in this order. [7] The multilayer structure according to [6], comprising a polyolefin substrate layer (G), a polyolefin adhesive layer (H), and a vinyl alcohol polymer layer (A), obtained by co-extrusion molding. [8] A multilayer structure according to [6] or [7], comprising a polyolefin substrate layer (G), a polyolefin adhesive layer (H), and a vinyl alcohol polymer layer (A) stretched in at least one axial direction. [9] A multilayer structure according to any one of [6] to [8], wherein the vinyl alcohol polymer layer (A) mainly comprises an ethylene-vinyl alcohol copolymer with an ethylene unit content of 10 to 65 mol% and a degree of saponification of 90 mol% or more.

[10] A multilayer structure according to any one of [1] to [5], wherein the vapor-deposited film (X) has a polyolefin substrate layer (G), a vinyl alcohol-based polymer layer (A), and a vapor-deposited layer (B) in this order.

[11] The multilayer structure according to

[10] , wherein a vinyl alcohol polymer layer (A) is formed by coating a polyolefin substrate layer (G) with a vinyl alcohol polymer solution or dispersion.

[12] The multilayer structure according to

[10] or

[11] , wherein the vinyl alcohol polymer layer (A) mainly comprises a vinyl alcohol polymer with an ethylene unit content of 50 mol% or less and a degree of saponification of 70 mol% or more.

[13] A multilayer structure according to any one of [1] to

[12] , having a plurality of polyolefin layers (C), one of which is an unstretched polyolefin layer and the other is a stretched polyolefin layer.

[14] A multilayer structure according to any one of items [1] to

[13] , which does not contain a layer mainly composed of a resin with a melting point of 200°C or higher, or a metal layer with a thickness of 1 μm or more. Packaging material including a multilayer structure as described in any one of items

[15] [1] to

[14] . A package comprising contents contained in the packaging material described in

[16]

[15] , A package containing the contents which include 5% by mass or more of water, and at least one selected from the group consisting of 1% by mass or more of lipids, 1% by mass or more of sodium chloride, and 0.5% by mass or more of acetic acid. A recovered composition comprising a recovered multilayer structure as described in any one of items

[17] [1] to

[14] . A method for recovering a multilayer structure, comprising crushing the multilayer structure described in any one of items

[18] , [1], to

[14] , and then melt-molding it. [Effects of the Invention]

[0009] The multilayer structure of the present invention exhibits excellent gas barrier properties and can maintain high gas barrier properties even when subjected to physical stress such as bending. As a result, it has excellent bending resistance and excellent barrier stability when packaging contents containing specific amounts of moisture, oil, etc., thus providing a multilayer structure with excellent storage stability for contents. Therefore, the multilayer structure of the present invention is suitable as a packaging material for packaging food and the like. Moreover, the multilayer structure of the present invention is easy to recover and re-melt-mold. [Brief explanation of the drawing]

[0010] [Figure 1] This graph plots the molar ratios (total 100 mol%) of silicon (Si), oxygen (O), and carbon (C) (100 mol%) of the vapor-deposited layer (B) described in Example 2 against the sputtering time, as analyzed by a scanning X-ray photoelectron spectroscopy analyzer. [Figure 2] This graph plots the molar ratio (O / Si) calculated from Figure 1 against the sputtering time. [Figure 3] This graph plots the molar ratios (total 100 mol%) of silicon (Si), oxygen (O), and carbon (C) (100 mol%) of the vapor-deposited layer (B) described in Comparative Example 5 against the sputtering time, as analyzed by a scanning X-ray photoelectron spectroscopy analyzer. [Figure 4] This graph plots the molar ratio (O / Si) calculated from Figure 3 against the sputtering time. [Modes for carrying out the invention]

[0011] In this specification, "gas barrier properties" means the ability to block gases other than water vapor unless otherwise specified. Furthermore, in this specification, when simply referred to as "barrier properties," it means both gas barrier properties and water vapor barrier properties. The property of "maintaining high barrier properties even when subjected to physical stress such as bending" may be expressed as "flexural resistance." In this specification, when describing layer configurations, " / " indicates direct lamination, and " / / " indicates lamination either directly or via an adhesive layer. The "uppermost layer" is not limited to only the layer existing on the front side, distinguishing between the front and the back. That is, a vapor deposition film or a multilayer structure composed of two or more layers has two uppermost layers, namely, the uppermost layer on one surface side and the uppermost layer on the other surface side. Also, in the case of a structure with a distinction between the inside and the outside, such as a bag shape or a container shape, the innermost uppermost layer may be referred to as the innermost layer, and the outermost uppermost layer may be referred to as the outermost layer. The "main component" refers to the component with the highest content based on mass. The "thickness" of a layer or a film in this specification refers to the average value of the thickness measured at any five locations.

[0012] <Vapor deposition film> The vapor deposition film of the present invention is a vapor deposition film (X) containing a vinyl alcohol-based polymer layer (A) and a vapor deposition layer (B) composed of silicon oxide or a metal oxide, where the vapor deposition layer (B) with a thickness of 30 nm or more and 200 nm or less is directly formed on the surface of the vinyl alcohol-based polymer layer (A), Taking the surface of the vapor deposition layer (B) on the side of the vinyl alcohol-based polymer layer (A) as surface (b1) and the opposite surface of the vapor deposition layer (B) as surface (b2), when performing elemental analysis of the vapor deposition layer (B) in the depth direction with a scanning X-ray photoelectron spectrometer from surface (b2) to surface (b1), the molar ratio (O / M) of oxygen element (O) to silicon element or metal element (M) on surface (b1) b1 and the molar ratio (O / M) of oxygen element (O) to silicon element or metal element (M) at a position equidistant from surface (b1) and surface (b2) c The ratio of [(O / M) b1 / (O / M) c is 1.1 or more and 1.7 or less, which is the vapor deposition film (X).

[0013] The vapor-deposited film (X) of the present invention exhibits excellent gas barrier properties and flexibility. The reason for this is not entirely clear, but the following reasons are speculated. In the vapor-deposited film (X), oxygen atoms are segregated near the interface between the vinyl alcohol polymer layer (A) and the vapor-deposited layer (B), which is thought to increase the adhesion strength between the vinyl alcohol polymer layer (A) and the vapor-deposited layer (B). As a result, even when the vapor-deposited film is subjected to bending treatment, the vinyl alcohol polymer layer (A) maintains a state of strong adhesion with the vapor-deposited layer (B), and it is speculated that the decrease in gas barrier properties after bending treatment is suppressed. Furthermore, even when packaging contents containing a large amount of moisture or oil, it is speculated that the vinyl alcohol polymer layer (A) maintains a state of strong adhesion with the vapor-deposited layer (B), thereby suppressing the deterioration of the contents.

[0014] (Vinyl alcohol-based polymer layer (A)) The vinyl alcohol polymer layer (A) mainly contains a vinyl alcohol polymer. The vinyl alcohol polymer can be any polymer containing vinyl alcohol units, and may be polyvinyl alcohol (hereinafter sometimes referred to as PVOH) or ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as EVOH). If the vinyl alcohol polymer layer (A) is formed by melt molding, ethylene-vinyl alcohol copolymer is preferred.

[0015] PVOH is a polymer having vinyl alcohol units as monomer units. PVOH is usually obtained by saponifying polyvinyl esters. The lower limit of the ratio of vinyl alcohol units to total monomer units in PVOH is preferably 50 mol%, more preferably 60 mol%, and even more preferably 70 mol%. Good water solubility is achieved by setting the ratio of vinyl alcohol units above the above lower limit. On the other hand, the upper limit of the ratio of vinyl alcohol units may be 100 mol%, but is preferably 99.99 mol%, and more preferably 99 mol%.

[0016] The lower limit of the degree of saponification of PVOH is preferably 35 mol%, more preferably 50 mol%, even more preferably 70 mol%, and particularly preferably 75 mol%. On the other hand, the upper limit of the degree of saponification may be 100 mol%, but is preferably 99 mol%, more preferably 95 mol%, even more preferably 92 mol%, and particularly preferably less than 88 mol%. By setting the degree of saponification within the above range, the surface tension can be effectively reduced. The degree of saponification is a value measured by the method described in JIS K6726:1994.

[0017] The average degree of polymerization of PVOH is not particularly limited, but is preferably 200 or higher, more preferably 400 or higher, even more preferably 600 or higher, and especially preferably 800 or higher. The above average degree of polymerization is preferably 5,000 or lower, more preferably 4,000 or lower, and even more preferably 3,000 or lower. By setting the average degree of polymerization within the above range, it is possible to effectively reduce the surface tension while suppressing the thickening of the solution. The average degree of polymerization is the viscosity-average degree of polymerization measured in accordance with JIS K6726:1994. That is, after resaponifying PVOH to a degree of saponification of 99.5 mol% or higher and purifying it, it can be determined from the intrinsic viscosity [η] (unit: liters / g) measured in water at 30°C using the following formula. Viscosity average degree of polymerization=([η]×10 4 (8.29) (1 / 0.62)

[0018] EVOH is usually obtained by saponifying copolymers of ethylene and vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versaticate. The production and saponification of copolymers of ethylene and vinyl esters can be carried out by known methods. The degree of saponification of the vinyl ester component of the ethylene-vinyl alcohol copolymer is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. By setting the degree of saponification to 90 mol% or more, the gas barrier properties can be improved. The degree of saponification of the ethylene-vinyl alcohol copolymer may be 100 mol% or less, or 99.99 mol% or less. The degree of saponification of the ethylene-vinyl alcohol copolymer is determined by nuclear magnetic resonance ( 1 The peak area of ​​hydrogen atoms in the vinyl ester structure and the peak area of ​​hydrogen atoms in the vinyl alcohol structure are determined by performing 1H-NMR measurements.

[0019] When subjected to melt molding, the ethylene unit content of the ethylene-vinyl alcohol copolymer is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and even more preferably 25 mol% or more. Furthermore, the ethylene unit content of the ethylene-vinyl alcohol copolymer is preferably 65 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less. When the ethylene unit content is 10 mol% or more, good gas barrier properties and flexural resistance under high humidity tend to be maintained. On the other hand, when the ethylene unit content is 65 mol% or less, gas barrier properties can be enhanced. The ethylene unit content of the ethylene-vinyl alcohol copolymer can be determined by NMR spectroscopy.

[0020] On the other hand, when the vinyl alcohol polymer layer (A) is formed by coating with a solution or dispersion, the ethylene unit content is preferably 50 mol% or less, and more preferably 40 mol% or less. The solvent is not particularly limited and may be water or an organic solvent such as alcohol. When an aqueous solution is used, the ethylene unit content is preferably 20 mol% or less, more preferably 15 mol% or less, and even more preferably 10 mol% or less. The ethylene unit content may be 0 mol% or more, or 1 mol% or more.

[0021] Furthermore, the vinyl alcohol polymer may have units derived from monomers other than ethylene, vinyl esters and their saponifies, to the extent that the objectives of the present invention are not hindered. When the vinyl alcohol polymer has the aforementioned other monomer units, the content of these other monomer units relative to the total monomer units of the vinyl alcohol polymer is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and particularly preferably 5 mol% or less. Also, when the vinyl alcohol polymer has the aforementioned other monomer units, the lower limit may be 0.05 mol% or 0.10 mol%. Other monomers include, for example, alkenes such as propylene, butylene, pentene, and hexene; 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4-diasiloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl- 1-Butene, 3,4-Diacyloxy-2-methyl-1-butene, 4-Acyloxy-1-pentene, 5-Acyloxy-1-pentene, 4,5-Diacyloxy-1-pentene, 4-Acyloxy-1-hexene, 5-Acyloxy-1-hexene, 6-Acyloxy-1-hexene, 5,6-Diacyloxy-1-hexene, 1,3-Diacetoxy-2-methylene Examples include alkenes having ester groups such as ropane or their saponifies; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid, or their anhydrides, salts, or mono- or dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; olefin sulfonic acids such as vinylsulfonic acid, allylsulfonic acid, and methallylsulfonic acid or their salts; vinylsilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane, and γ-methacryloxypropylmethoxysilane; alkyl vinyl ethers, vinyl ketones, N-vinylpyrrolidone, vinyl chloride, and vinylidene chloride.

[0022] Furthermore, if the vinyl alcohol polymer is a compound of two or more different vinyl alcohol polymers, the average ethylene unit content or degree of saponification of the entire vinyl alcohol polymer shall be used as the ethylene unit content or degree of saponification of the vinyl alcohol polymer.

[0023] The MFR (at 190°C, 2.16 kg load) of the vinyl alcohol polymer is preferably 0.5 g / 10 min to 12 g / 10 min, and more preferably 1.0 g / 10 min to 8.0 g / 10 min. The average degree of polymerization of the vinyl alcohol polymer is preferably 200 to 5000.

[0024] In the resin constituting the vinyl alcohol polymer layer (A), the lower limit of the proportion of vinyl alcohol polymer is preferably 70% by mass, more preferably 80% by mass, even more preferably 90% by mass, and may also be 95% by mass, 99% by mass, or 99.9% by mass, or even 100% by mass, from the viewpoint of gas barrier properties, etc.

[0025] The lower limit of the content of the vinyl alcohol polymer in the vinyl alcohol polymer layer (A) is preferably 70% by mass, more preferably 80% by mass, even more preferably 90% by mass, and may also be 95% by mass, 99% by mass, or 99.9% by mass, from the viewpoint of gas barrier properties, etc. The upper limit of the content of the vinyl alcohol polymer in the vinyl alcohol polymer layer (A) may be 100% by mass or 99.99% by mass.

[0026] The vinyl alcohol polymer layer (A) may optionally contain inorganic oxide particles. The inorganic oxides constituting the inorganic oxide particles are not particularly limited, but examples include silicon oxide, aluminum oxide, magnesium oxide, zirconium oxide, cerium oxide, tungsten oxide, molybdenum oxide, and composites thereof. Among these, silicon oxide or silicon oxide-magnesium oxide is preferred, and silicon oxide is more preferred.

[0027] The lower limit of the inorganic oxide particle content in the vinyl alcohol polymer layer (A) is preferably 0.001% by mass, more preferably 0.005% by mass, and even more preferably 0.01% by mass. The upper limit of the inorganic oxide particle content is preferably 1% by mass, more preferably 0.7% by mass, and even more preferably 0.5% by mass. When the inorganic oxide particle content is within the above range, the gas barrier properties tend to be further improved.

[0028] The average particle size of the inorganic oxide particles is preferably 1 μm to 10 μm, and more preferably 2 μm to 5 μm. When the average particle size of the inorganic oxide particles is within the above range, the gas barrier properties tend to improve. The average particle size of the inorganic oxide particles is defined as the d50 value measured by laser diffraction scattering.

[0029] The vinyl alcohol polymer layer (A) may also contain boron compounds, carboxylic acids, phosphorus compounds, metal ions, antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, heat stabilizers, etc., and may contain two or more of these optional components.

[0030] When a vinyl alcohol-based polymer layer (A) is formed by melt molding, the vinyl alcohol-based polymer layer (A) may be an unstretched layer or a stretched layer, but from the viewpoint of dimensional stability and gas barrier properties, a layer stretched in at least one axis direction is preferred, and a layer stretched in two axes is more preferred. As for the stretching ratio, from the viewpoint of thickness uniformity, barrier properties, mechanical properties and film formation properties, a range of 2.5 to 4.5 times in the longitudinal direction (MD direction), 2.5 to 4.5 times in the transverse direction (TD direction), and a surface stretching ratio of 7 to 15 times is preferred, and a range of 2.5 to 3.5 times in the longitudinal direction, 2.5 to 3.5 times in the transverse direction, and a surface stretching ratio of 8 to 12 times is more preferred. Such stretching treatment can be carried out according to known methods such as simultaneous biaxial stretching and sequential biaxial stretching, which are commonly performed.

[0031] The thickness of the vinyl alcohol polymer layer (A) is not particularly limited, but is preferably 0.1 μm to 20 μm. A thickness of 0.1 μm or more for the vinyl alcohol polymer layer (A) improves the gas barrier properties of the vapor-deposited film. A thickness of 0.2 μm or more for the vinyl alcohol polymer layer (A) is more preferable, and 0.5 μm or more is even preferable. The vinyl alcohol polymer layer (A) can also be formed by coating a vinyl alcohol polymer solution onto another resin, or by co-extruding a vinyl alcohol polymer together with another resin to form a multilayer film, and then stretching the multilayer film as needed to form the vinyl alcohol polymer layer (A). It is preferable to form a co-extruded multilayer film and stretch the multilayer film as needed. Furthermore, a thickness of 20 μm or less for the vinyl alcohol polymer layer (A) facilitates the recovery of the multilayer structure by mixing it with polyolefin and melt-kneading it for recovery and reuse, resulting in excellent recyclability. The thickness of the vinyl alcohol polymer layer (A) is more preferably 10 μm or less, even more preferably 8 μm or less, and particularly preferably 6 μm or less. Note that "thickness" refers to the average value measured at any five points, and the same applies to the thickness of other layers described herein.

[0032] It is also preferable that the ratio of the thickness of the vinyl alcohol-based polymer layer (A) to the thickness of the multilayer structure is less than 25%. Having a ratio of less than 25% facilitates the recovery of the multilayer structure by mixing it with polyolefin and melt-kneading it for reuse, resulting in excellent recyclability. The ratio of the thickness of the vinyl alcohol-based polymer layer (A) to the thickness of the multilayer structure is more preferably less than 20%, and even more preferably less than 15%. In cases where particularly good recyclability is required, it is more preferably less than 10%, and even more preferably less than 5%.

[0033] The oxygen permeability of the vinyl alcohol polymer layer (A) is 50 mL·20 μm / (m²). 2 Preferably less than 10 mL·20 μm / (m²) 2(day·atm) or less is more preferable 5 mL·20 μm / (m 2 (day·atm) or less is more preferable, 1 mL·20 μm / (m 2 A value of less than or equal to (day·atm) is particularly preferred. Here, the oxygen permeability is the value obtained by measuring a 20 μm thick film under conditions of 20°C and 65% RH in accordance with the method described in ISO 14663-2 Annex C (1999).

[0034] (Vapor deposited layer (B)) A vapor-deposited layer (B) made of silicon dioxide or a metal oxide can be effectively formed, for example, by vacuum deposition. For example, when vacuum deposition is performed on a resin film that will become a vinyl alcohol polymer layer (A) using silicon dioxide or a metal oxide, it is important to perform the deposition while supplying an appropriate amount of oxygen gas to the resin film. This forms a vapor-deposited layer (B) with segregated oxygen near the interface with the vinyl alcohol polymer layer (A). The degree of segregation can be controlled by the amount of oxygen gas supplied to the resin film. The amount of oxygen gas supplied to the resin film is preferably, for example, 0.1 mL / min to 10 mL / min, more preferably 0.2 mL / min to 5 mL / min, and even more preferably 0.3 mL / min to 1 mL / min. However, the appropriate amount of oxygen gas supplied is adjusted as needed depending on conditions such as the deposition rate of silicon dioxide or the metal oxide. Furthermore, a vapor-deposited layer (B) with segregated oxygen may be formed by a vapor deposition method other than those described above. For example, the vapor-deposited layer (B) may be formed by sputtering, ion plating, ion beam mixing, plasma CVD, laser CVD, MO-CVD, thermal CVD, or the like.

[0035] Before deposition, the surface of the vinyl alcohol-based polymer layer (A) to be deposited may be plasma-treated. Known methods can be used for plasma treatment, and atmospheric pressure plasma treatment is preferred. Examples of discharge gases used in atmospheric pressure plasma treatment include nitrogen gas, helium, neon, argon, krypton, xenon, and radon.

[0036] Silicon oxide or metal oxide (MO X The vapor-deposited layer (B) consists of silicon dioxide (SiO₂). X It consists of ) or a metal oxide. Here, M represents silicon or a metallic element. Examples of metal oxides include aluminum oxide (AlO X Examples include magnesium oxide, calcium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide. Among these, a vapor-deposited layer made of aluminum oxide or silicon oxide is preferred, and a vapor-deposited layer made of silicon oxide is more preferred. Silicon oxide or metal oxide (MO X By providing a vapor-deposited layer (B) consisting of the above, the resulting vapor-deposited film (X) exhibits excellent transparency and recyclability.

[0037] In the vapor-deposited film (X) of the present invention, the side of the vapor-deposited layer (B) facing the ethylene-vinyl alcohol copolymer layer (A) is designated as surface (b1), and the opposite side of the vapor-deposited layer (B) is designated as surface (b2). When elemental analysis of the vapor-deposited layer (B) is performed in the depth direction from surface (b2) to surface (b1) using a scanning X-ray photoelectron spectroscopy analyzer, the molar ratio (O / M) of oxygen element (O) to silicon element or metal element (M) on surface (b1) is determined. b1 And the molar ratio (O / M) of oxygen element to silicon element or metal element (M) at positions equidistant from plane (b1) and plane (b2). c The ratio [(O / M)] b1 / (O / M) c The most distinctive feature is that the value is between 1.1 and 1.7.

[0038] The following describes the elemental analysis of the vapor-deposited layer (B) in the depth direction using a scanning X-ray photoelectron spectroscopy analyzer, with reference to Figures 1-4. Figure 1 is a graph plotting the molar ratios (total 100 mol%) of silicon (Si), oxygen (O), and carbon (C) against sputtering time when the vapor-deposited layer (B) described in Example 2 was analyzed using a scanning X-ray photoelectron spectroscopy analyzer. Figure 2 is a graph plotting the molar ratio (O / Si) calculated from Figure 1 against sputtering time. Sputtering time 0 minutes is the outermost surface of the vapor-deposited layer (B), corresponding to surface (b2). Near surface (b2) exposed to the outside air, the amount of C and O increases due to the adsorption and oxidation of organic matter. On the other hand, near surface (b1) in contact with the vinyl alcohol polymer layer (A), the composition of the vapor-deposited layer (B) becomes unstable due to the influence of the vinyl alcohol polymer layer (A). Therefore, the molar ratio (O / M) at a position equidistant from surfaces (b1) and (b2) (center) c This was adopted as the reference value. Since the etching rate of the vapor-deposited layer (B) is considered to be almost constant, the "position equidistant from surface (b1) and surface (b2)" corresponds to half the sputtering time of surface (b1). Here, surface (b1) corresponds to the time when the proportion of carbon elements derived from the vinyl alcohol polymer layer (A) becomes 1 mol%, indicating the point at which the substrate begins to be affected. Furthermore, in the vapor-deposited film described in Example 2, a characteristic feature is that the oxygen concentration in the vapor-deposited layer (B) increases near surface (b1) because the film was formed while supplying oxygen to the vicinity of the surface of the vinyl alcohol polymer layer (A) of the substrate.

[0039] The ratio calculated in this way [(O / M)] b1 / (O / M) c By having a ratio of 1.1 or higher, the decrease in gas barrier properties after bending can be suppressed. Here, the ratio [(O / M) b1 / (O / M) cA large ratio indicates that the oxygen content in the vapor-deposited layer (B) is high near the interface between the vinyl alcohol polymer layer (A) and the vapor-deposited layer (B). This is presumed to improve the adhesion between the vinyl alcohol polymer layer (A) and the vapor-deposited layer (B), making it less likely for the gas barrier properties to deteriorate even after bending. As shown in later examples, when the film substrate is polyester or polyamide, even if the film is formed under similar conditions, the ratio [(O / M) b1 / (O / M) c The ratio [(O / M) ] was less than 1.1, indicating insufficient gas barrier properties after bending treatment. This suggests that differences in substrates alter the state of oxygen near the interface with the substrate, thus changing the degree of oxidation of the vapor-deposited layer (B). b1 / (O / M) c ] is preferably 1.13 or higher, and more preferably 1.15 or higher. On the other hand, the ratio [(O / M) b1 / (O / M) c By having a ratio of 1.7 or less, the reduction in the gas barrier properties of the vapor-deposited layer (B) after the storage test can be suppressed. Ratio [(O / M) b1 / (O / M) c ] is preferably 1.5 or less, and more preferably 1.3 or less.

[0040] The molar ratio (O / M) of oxygen element to silicon element or metal element (M) on surface (b1) b1 It is preferable that the ratio is between 1.85 and 2.35. Molar ratio (O / M) b1 A molar ratio of 1.85 or higher improves the adhesion between the vapor-deposited layer (B) and the vinyl alcohol-based polymer layer (A), thereby suppressing the decrease in gas barrier properties after bending treatment. b1 More preferably, it is 1.95 or higher, even more preferably 2.0 or higher, and particularly preferably 2.05 or higher. On the other hand, the molar ratio (O / M) b1 A homogeneous vapor-deposited layer (B) can be formed if the molar ratio is 2.35 or less. b1 More preferably, it is 2.3 or less.

[0041] Also, the molar ratio (O / M) of oxygen element to silicon element or metal element (M) at positions equidistant from surfaces (b1) and (b2). c It is preferable that the ratio is between 1.5 and 2.0. Molar ratio (O / M) c A molar ratio of 1.5 or higher suppresses the decrease in the gas barrier properties of the vapor-deposited layer (B) after storage testing. c More preferably, it is 1.55 or higher, even more preferably 1.6 or higher, particularly preferably 1.65 or higher, and in some cases, 1.80 or higher is preferred, as is 1.81 or higher. On the other hand, the molar ratio (O / M) c As long as it is 2.0 or less, (O / M) b1 This makes it easier to increase the difference between the two. Molar ratio (O / M) c More preferably, it is 1.95 or less, and even more preferably, 1.9 or less.

[0042] The thickness of the vapor-deposited layer (B) is 30 nm or more and 200 nm or less. The lower limit of the thickness of the vapor-deposited layer (B) is preferably 40 nm, and more preferably 50 nm. By having a thickness of the vapor-deposited layer (B) greater than or equal to the lower limit, the gas barrier properties and flexibility of the vapor-deposited film can be further improved. The upper limit of the thickness of the vapor-deposited layer (B) is preferably 180 nm, and may also be 160 nm or 140 nm.

[0043] The thickness of the vapor-deposited film (X) of the present invention is not particularly limited, and the lower limit may be, for example, 5 μm, 8 μm, or 10 μm. On the other hand, the upper limit of the thickness may be, for example, 100 μm, 50 μm, 30 μm, or 20 μm.

[0044] The oxygen permeability of the vapor-deposited film (X) of the present invention is 1.0 mL / (m²). 2 It is preferable that it be less than 0.10 mL / (m³) 2 It is more preferable that it be less than 0.08 mL / (m³) day·atm. 2 It is even more preferable that it be less than 0.05 mL / (m³) day·atm. 2It is particularly preferable that the oxygen permeability is less than the above upper limit (day·atm). Having an oxygen permeability below the above upper limit makes it particularly suitable for use as various packaging materials, etc. On the other hand, the lower limit of this oxygen permeability is 0 mL / (m³). 2 It may also be 0.001 mL / (m³) 2 It may also be (day·atm). The oxygen permeability of the vapor-deposited film (X) is the value measured in accordance with the method described in ISO 14663-2 Annex C (1999) under conditions of 20°C and 65% RH.

[0045] In a preferred embodiment, the vapor-deposited film (X) comprises a polyolefin substrate layer (G), a polyolefin adhesive layer (H), a vinyl alcohol polymer layer (A), and a vapor-deposited layer (B) in this order. In this case, these layers are in direct contact with each other. Preferably, the polyolefin substrate layer (G), the polyolefin adhesive layer (H), and the vinyl alcohol polymer layer (A) are formed by co-extrusion molding. Co-extrusion molding improves productivity and makes it easier to thin the vinyl alcohol polymer layer (A). Furthermore, it is preferable that the polyolefin substrate layer (G), the polyolefin adhesive layer (H), and the vinyl alcohol polymer layer (A) are stretched in at least one axial direction. More preferably, they are stretched in two axial directions. The stretching ratio and stretching conditions are as described above for the vinyl alcohol polymer layer (A). This makes it possible to further thin the vinyl alcohol polymer layer (A) and improves its elastic modulus.

[0046] When co-extruding a polyolefin substrate layer (G), a polyolefin adhesive layer (H), and a vinyl alcohol polymer layer (A), it is preferable that the vinyl alcohol polymer layer (A) mainly contains an ethylene-vinyl alcohol copolymer with an ethylene unit content of 10 to 65 mol% and a degree of saponification of 90 mol% or more. A ethylene unit content of 10 mol% or more results in good melt moldability. More preferably, the ethylene unit content is 15 mol% or more, even more preferably 20 mol% or more, and particularly preferably 25 mol% or more. On the other hand, a ethylene content of 65 mol% or less results in good gas barrier properties. More preferably, the ethylene unit content is 60 mol% or less, even more preferably 55 mol% or less, and particularly preferably 50 mol% or less. Furthermore, a degree of saponification of 90 mol% or more results in excellent melt stability. More preferably, the degree of saponification is 95 mol% or more, even more preferably 98 mol% or more, and particularly preferably 99 mol% or more.

[0047] In other preferred embodiments, the vapor-deposited film (X) has a polyolefin substrate layer (G), a vinyl alcohol polymer layer (A), and a vapor-deposited layer (B) in this order. In this case, these layers may be in direct contact with each other or may be separated by an adhesive layer. Preferably, the vinyl alcohol polymer layer (A) is formed by coating the polyolefin substrate layer (G) with a solution or dispersion of the vinyl alcohol polymer. This makes it easy to make the vinyl alcohol polymer layer (A) thin. When a solution is used, a suitable solvent is alcohol, water, or a mixture thereof. Examples of alcohols include methanol, ethanol, 1-propanol, and 2-propanol. When a dispersion is used, a suitable dispersion medium is water.

[0048] When forming a vinyl alcohol polymer layer (A) by coating a polyolefin substrate layer (G) with a vinyl alcohol polymer solution or dispersion, it is preferable that the vinyl alcohol polymer layer (A) mainly contains a vinyl alcohol polymer with an ethylene unit content of 50 mol% or less and a degree of saponification of 70 mol% or more. Having an ethylene unit content of 50 mol% or less ensures good solubility in the solvent. More preferably, the ethylene unit content is 40 mol% or less. When dissolving in water or a water / alcohol mixed solvent, the ethylene unit content is more preferably 20 mol% or less, even more preferably 15 mol% or less, and particularly preferably 10 mol% or less. The ethylene unit content may be 0 mol%, but from the viewpoint of water solubility, it may be 1 mol% or more.

[0049] The vapor-deposited film (X) of the present invention exhibits excellent gas barrier properties and flexibility. Furthermore, the vapor-deposited film (X) can suppress the deterioration of gas barrier properties after storage testing. For these reasons, the vapor-deposited film (X) can be applied to a variety of uses. Examples of applications for the vapor-deposited film (X) include various packaging materials such as food packaging, pharmaceutical packaging, industrial chemical packaging, and pesticide packaging, as well as vacuum packaging bags and vacuum insulation materials.

[0050] <Multilayer structure> The multilayer structure of the present invention is a multilayer structure comprising a vapor-deposited film (X) and a polyolefin layer (C) laminated together. The ratio of the thickness of the polyolefin-based layer to the total thickness of the multilayer structure is 75% or more. A high proportion of polyolefin results in excellent recyclability. The ratio of the thickness of the polyolefin-based layer is more preferably 85% or more, even more preferably 90% or more, and particularly preferably 95% or more. Here, the polyolefin-based layer is not limited to the "polyolefin layer (C)," but may also include a "polyolefin substrate layer (G)," a "polyolefin-based adhesive layer (H)," an EVOH layer with an ethylene unit content of 25 mol% or more, or any other layer that contains a resin with an olefin unit content of 25 mol% or more in molar ratio as its main component. From the viewpoint of better recyclability, a layer containing a resin with an olefin unit content of 50 mol% or more in molar ratio may be considered a polyolefin-based layer.

[0051] (Polyolefin layer (C)) The multilayer structure of the present invention is a multilayer structure comprising a vapor-deposited film (X) and a polyolefin layer (C) of the present invention laminated together. That is, it comprises a vapor-deposited film (X) and a polyolefin layer (C) laminated directly or via another layer to at least one surface of the vapor-deposited film (X). When the multilayer structure comprises a polyolefin layer (C) together with the vapor-deposited film (X), it is possible to enhance not only gas barrier properties but also water vapor barrier properties. Furthermore, when the polyolefin layer (C) is the outermost layer of the multilayer structure, it becomes possible to easily form it into a bag-like shape, for example, by heat-sealing the polyolefin layer (C) as a heat-sealable layer. In the multilayer structure of the present invention, the innermost layer when formed into a bag-like shape may be the polyolefin layer (C).

[0052] The polyolefin layer (C) may be directly laminated onto the vapor-deposited film (X) of the present invention, or it may be laminated via another layer. Examples of other layers include adhesive layers. Examples of adhesive layers include layers made of curing adhesives (such as two-component reaction-type polyurethane adhesives).

[0053] Polyethylene or polypropylene is preferred as the polyolefin constituting the polyolefin layer (C).

[0054] The polyolefin layer (C) may be an unstretched layer or a stretched layer. In the multilayer structure of the present invention, when the innermost layer is the polyolefin layer (C) when formed into a bag shape, it is preferable that the innermost polyolefin layer (C) is an unstretched layer from the viewpoint of good heat sealability.

[0055] The lower limit of the thickness of the polyolefin layer (C) is preferably 5 μm, more preferably 10 μm, even more preferably 15 μm, and may also be 20 μm, 30 μm, or 40 μm. A thickness of the polyolefin layer (C) greater than or equal to the above lower limit allows for sufficient moisture resistance. Furthermore, if the polyolefin layer (C) is the outermost layer, a thickness of the polyolefin layer (C) greater than or equal to the above lower limit allows for sufficient heat sealability. The upper limit of the thickness of the polyolefin layer (C) is preferably 200 μm, more preferably 100 μm, and may also be 60 μm or 40 μm. A thickness of the polyolefin layer (C) less than or equal to the above upper limit allows for thinning of the multilayer structure.

[0056] The polyolefin content in the polyolefin layer (C) is preferably 80% to 100% by mass, more preferably 90% to 100% by mass, and even more preferably 97% to 100% by mass. The polyolefin layer (C) may also contain components other than polyolefin, such as antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, heat stabilizers, and other resins other than polyolefin.

[0057] The polyolefin layer (C) may consist of a single layer or multiple layers. It is also preferable to have multiple polyolefin layers (C), one of which is an unstretched polyolefin layer and the other is a stretched polyolefin layer. The unstretched polyolefin layer has good heat sealability when used as a sealant layer. The stretched polyolefin layer has excellent rigidity and excellent water vapor barrier properties.

[0058] The multilayer structure of the present invention preferably does not contain layers mainly composed of resin with a melting point of 200°C or higher, or metal layers with a thickness of 1 μm or more. If such layers are included, it becomes difficult to melt and knead the multilayer structure at low temperatures when it is recovered and melt-kneaded, making it difficult to recycle together with polyolefins. Therefore, it is preferable that the multilayer structure of the present invention does not contain polyester layers, polyamide layers, aluminum foil, etc.

[0059] (Other vapor-deposited films (Y)) The multilayer structure of the present invention may further comprise other vapor-deposited films (Y) laminated directly or via other layers to the vapor-deposited film (X) of the present invention. In other words, the multilayer structure of the present invention may comprise a plurality of vapor-deposited films, and at least one of the plurality of vapor-deposited films may be the vapor-deposited film (X) of the present invention. As the vapor-deposited film (Y), for example, a vapor-deposited film (Y) comprising a polyolefin layer and a vapor-deposited layer (E) made of silicon oxide or a metal oxide is preferred. Here, a biaxially oriented polypropylene layer is preferred as the polyolefin layer. Furthermore, as the vapor-deposited layer (E), a silicon oxide or aluminum oxide layer can be formed with the same thickness as the vapor-deposited layer (B). A multilayer structure comprising a plurality of vapor-deposited films has superior gas barrier properties. The plurality of vapor-deposited films may be laminated directly to each other or laminated via other layers. An adhesive layer is preferred as the other layer. Multiple layers may exist between the plurality of vapor-deposited films.

[0060] When the multilayer structure of the present invention has an adhesive layer, the thickness of the adhesive layer is preferably, for example, 0.1 μm to 10 μm, more preferably 0.3 μm to 7 μm, and even more preferably 0.5 μm to 5 μm. By setting the thickness of the adhesive layer within the above range, it is possible to achieve sufficient adhesion while reducing the weight of the multilayer structure. A polyurethane-based adhesive is suitable as the adhesive.

[0061] (Layer composition) The layer configuration of the multilayer structure of the present invention can be, for example, (1) Vinyl alcohol-based polymer layer (A) / Vapor-deposited layer (B) / Polyolefin layer (C) (2) C / / A / B / / C (3) Polyolefin substrate layer (G) / A / B / / C (4) C / / G / A / B / / C (5) G / Polyolefin adhesive layer (H) / A / B / / C (6) C / / G / H / A / B / / C These are some examples.

[0062] The lower limit of the thickness of the multilayer structure of the present invention (the total thickness of the multilayer structure) is preferably 10 μm, but may be 20 μm, 30 μm, or 50 μm. A thickness of the multilayer structure greater than or equal to the above lower limit can further enhance gas barrier properties and flexibility. The upper limit of the thickness of the multilayer structure is preferably 1,000 μm, but may be 500 μm, 300 μm, 200 μm, or 100 μm.

[0063] The method for manufacturing the multilayer structure of the present invention is not particularly limited. For example, a multilayer structure can be obtained by laminating a polyolefin layer (C) film or the like onto the vapor-deposited film (X) of the present invention by known means such as dry lamination.

[0064] Applications of the multilayer structure of the present invention include, for example, various packaging materials such as food packaging, pharmaceutical packaging, industrial chemical packaging, and pesticide packaging.

[0065] <Packaging material> The packaging material of the present invention includes the multilayer structure of the present invention. The packaging material is used for packaging purposes and its shape is not limited. The packaging material may be in the form of a sheet or molded into a predetermined shape such as a bag. From the viewpoint of heat sealability, it is preferable that the polyolefin layer (C) is located as the outermost layer as a heat-sealable layer. Also from the viewpoint of heat sealability, it is preferable that the polyolefin layer (C) located on the outermost layer is not stretched. In the case of a packaging material molded into a shape having an inner and outer layer, such as a bag, it is preferable that at least the polyolefin layer (C) is located in the innermost layer. Also, it is preferable that the vapor-deposited layer (B) is located outside the vinyl alcohol-based polymer layer (A).

[0066] The packaging material of the present invention is used for packaging, for example, food, beverages, pharmaceuticals, medical equipment, machine parts, clothing, etc. In particular, the packaging material is preferably used in applications where oxygen barrier properties are required, and in applications where the inside of the packaging material is replaced with various functional gases. Because the packaging material comprises the vapor-deposited film (X) of the present invention, the decrease in gas barrier properties after bending is suppressed, and it is possible to maintain high gas barrier properties over a long period of time. Furthermore, it is suitable as a packaging material for containing contents that contain 5% by mass or more of water and at least one selected from the group consisting of 1% by mass or more of lipids, 1% by mass or more of sodium chloride, and 0.5% by mass or more of acetic acid. The packaging material of the present invention does not easily lose gas barrier properties even when containing foods with a high moisture content.

[0067] The packaging material can be formed into various forms depending on its intended use, such as vertically constructed, filled, and sealed bags, spouted pouches, laminated tube containers, container lids, vacuum packaging bags, and the like.

[0068] Vertical-fold sealed bags are used to package foods, beverages, and other products in the form of liquids, viscous materials, powders, solid bulk materials, or combinations thereof. Vertical-fold sealed bags are formed by heat-sealing a multilayer structure. When heat sealing is performed, it is usually necessary to place a heat-sealable layer (e.g., a polyolefin layer (C)) in the layer that will be the inside of the vertical-fold sealed bag, or in both the inside and outside layers of the multilayer structure. If the heat-sealable layer is only on the inside of the vertical-fold sealed bag, the body is usually sealed by gusset sealing. If the heat-sealable layer is on both the inside and outside of the vertical-fold sealed bag, the body is usually sealed by envelope sealing.

[0069] Spout pouches are used to package liquid substances such as soft drinks, jelly drinks, yogurt, fruit sauces, seasonings, functional water, and liquid foods. Laminated tube containers are used to package cosmetics, pharmaceuticals, medicines, food products, toothpaste, etc. Container lids are lids for containers filled with foods such as processed meat products, processed vegetables, processed seafood products, and fruits.

[0070] The vacuum packaging bag comprises a packaging bag formed from the packaging material of the present invention, and the inside of the packaging bag is under reduced pressure. The vacuum packaging bag is suitable for applications where packaging in a vacuum state is desired, such as the preservation of food and beverages, and as an outer packaging material for vacuum insulation. Because such a vacuum packaging bag is equipped with the vapor-deposited film (X) of the present invention, the decrease in gas barrier properties after bending is suppressed, and it is possible to maintain a high vacuum state for a long period of time. A multilayer structure suitably used in a vacuum packaging bag is preferably configured to include multiple vapor-deposited films (X). [Examples]

[0071] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In the examples, " / " indicates that the two layers flanking " / " are directly laminated, and " / / " indicates that the two layers flanking " / / " are laminated with an adhesive in between.

[0072] [Materials used in the examples and comparative examples] (Vinyl alcohol-based polymer) • EVOH-1: Ethylene-vinyl alcohol copolymer pellet (ethylene unit content 48 mol%, degree of saponification 99.9 mol%, MFR (190℃, 2.16 kg load) 6.4 g / 10 min, melting point 157℃) EVOH-2: Ethylene-vinyl alcohol copolymer pellets (ethylene unit content 32 mol%, degree of saponification 99.9 mol%, MFR (190℃, 2.16 kg load) 1.6 g / 10 min, melting point 183℃) • EVOH-3: Ethylene-vinyl alcohol copolymer pellets (ethylene unit content 3 mol%, degree of saponification 99.3 mol%, degree of polymerization 1700) • PVOH-1: Polyvinyl alcohol resin (saponification degree 98.5 mol%, polymerization degree 1700) (Polyolefin) • PP1: "Novatec (trademark) PP EA7AD" (manufactured by Nippon Polypropylene Co., Ltd., polypropylene, MFR (230℃, 2.16kg load) 1.4g / 10min, density 0.90g / cm³) 3 ) • PE1: "INNATE (trademark) TF80" (manufactured by DOW, linear low-density polyethylene, MFR (190℃, 2.16kg load) 1.6g / 10min, melting point 124℃, density 0.926g / cm³) 3 ) • MAhPP1: "Admar (trademark) QF500" (manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified polypropylene, MFR (230℃, 2.16kg load) 3.0g / 10min) • MAhPP2: "Admer (trademark) SF730" (manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified polyolefin, MFR (190℃, 2.16kg load) 2.7g / 10min) • MAhPE1: Admer (trademark) NF518 (manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified polyethylene, MFR (190℃, 2.16kg load) 3.1g / 10min, melting point 121℃, density 0.91g / cm³) 3 , acid value 1.8mgKOH / g) • BOPP: "Pyrene (trademark) Film-OT P2161" (manufactured by Toyobo Co., Ltd., biaxially oriented polypropylene film, 20 μm thickness) • CPP: "RXC-22" (manufactured by Mitsui Chemicals Tohcello Co., Ltd., unoriented polypropylene film, 50 μm thickness) • LLDPE: "Unilux® LS760C" (manufactured by Idemitsu Unitech Co., Ltd., unoriented linear low-density polyethylene film, 50 μm thick) (Other resins) • ADh1: "Takelac (registered trademark) A-520" (manufactured by Mitsui Chemicals, Inc., a polyol component of a two-component polyurethane adhesive) • ADh2: "Takenate (registered trademark) A-50" (manufactured by Mitsui Chemicals, Inc., isocyanate component of a two-component polyurethane adhesive) • ADh3: "Takelac (registered trademark) A-626" (manufactured by Mitsui Chemicals, Inc., a polyol component of a two-component polyurethane adhesive) • PET: "TRN-RTJ" (manufactured by Teijin Limited) • PA: "UBE Nylon (trademark) SF1018A" (manufactured by Ube Industries, Ltd.)

[0073] [Evaluation Method] (1) Molar ratio of the vapor-deposited layer (B) (O / M) Elemental analysis was performed on the vapor-deposited layer (B) of a vapor-deposited film (X), consisting of silicon oxide or metal oxide, using a scanning X-ray photoelectron spectrometer "PHIQuntera SXM" manufactured by ULVAC-PHI, Inc., while sputtering in the depth direction (from the surface (b2) side to the surface (b1) direction). The X-ray source was AlKα (1486.6 eV), the X-ray beam diameter was 100 μmφ (25 W, 15 kV), the measurement range was 300 μm x 300 μm, the signal acquisition angle was 45°, and the vacuum level was 1 x 10⁻⁶. -6The measurement was performed under Pa conditions. The molar ratio of oxygen (O) to silicon or metal (M) on surface (b1) was (O / M). b1 Let (b1) and (b2) be the molar ratio of oxygen (O) to silicon or metal (M) at equidistant positions from the planes (b1) and (b2). c Let their ratios be [(O / M)] b1 / (O / M) c The following was determined: Here, plane (b2) is the position where sputtering started, plane (b1) is the position where the carbon content originating from the EVOH layer (A) reached 1 mol%, and the position equidistant from plane (b1) and plane (b2) was defined as the midpoint of the etching time.

[0074] (2) Oxygen permeability (OTR) The oxygen permeation rate of the multilayer structures obtained in the examples and comparative examples was measured according to the method described in JIS K 7126-2 (isobaric method; 2006). Specifically, using an oxygen permeation analyzer (MOCON OX-TRAN2 / 21, manufactured by Modern Control Co., Ltd.), the oxygen permeation rate (unit: cc / (m³)) was measured under the following conditions: temperature 20°C, humidity 65%RH on the oxygen supply side, humidity 65%RH on the carrier gas side, oxygen pressure 1 atm, and carrier gas pressure 1 atm. 2 The temperature (day·atm) was measured. Nitrogen gas containing 2 volume% hydrogen gas was used as the carrier gas. The outer layer was positioned on the oxygen supply side, and the inner layer (sealant layer side) was positioned on the carrier gas side.

[0075] (3) OTR after storage test From the multilayer structures obtained in the examples and comparative examples, two A4-sized sheets (210 mm x 297 mm) were cut out, and the inner layers (sealant layers) were overlapped. Three sides were then heat-sealed to create a three-sided pouch. 50 g of mayonnaise was filled into the resulting three-sided pouch, and the opening was heat-sealed at 150°C to create a pouch (packaging) filled with contents. The resulting packaging was stored at 34°C and 78% RH for 30 days, then opened. The mayonnaise contents were removed and washed with water, and the OTR was measured using the method described in evaluation method (2) above.

[0076] (4) Oxygen permeability (OTR) of the vapor-deposited film after the bending test. A 20cm x 25cm sample was cut from the vapor-deposited film obtained in the examples and comparative examples, and a Gelboflex test (bending test) was performed in accordance with ASTM F 392 using a Gelboflex tester (BE-1005) manufactured by Tester Industries Co., Ltd. Specifically, the cut vapor-deposited film was formed into a 3.5-inch diameter cylinder at 23°C and a 50% RH atmosphere, and both ends were fixed to the Gelboflex tester. The initial gap was 7 inches, the gap at maximum bending was 1 inch, a 440-degree twist was applied in the first 3.5 inches of the stroke, and the following 2.5 inches was a linear horizontal movement. This reciprocating motion was repeated three times. A portion of the bent part of the vapor-deposited film after the bending test was cut out, and the oxygen permeability was measured according to the method described in evaluation method (2) above.

[0077] [Example 1] Using EVOH-1 as the material for the vinyl alcohol copolymer layer (A), MAhPP1 as the material for the polyolefin adhesive layer (H), and PP1 as the material for the polyolefin substrate layer (G), a three-layer multilayer film (vinyl alcohol copolymer layer (A) / polyolefin adhesive layer (H) / polyolefin substrate layer (G) = 50 μm / 50 μm / 500 μm) was manufactured using a co-extrusion film manufacturing apparatus. The thickness of the multilayer film was adjusted by appropriately changing the screw rotation speed and take-up roll speed. The extruder, extrusion conditions, and dies used are as follows. • Vinyl alcohol copolymer layer (A) Extruder: Single-screw extruder (Toyo Seiki Co., Ltd. Lab machine ME type CO-EXT) Screw: 20mm diameter, L / D20, full-flight screw Extrusion temperature: Feed unit / Compression unit / Measuring unit / Die = 175 / 220 / 220 / 220℃ • Polyolefin adhesive layer (H) Extruder: Single-screw extruder (Technovel Corporation SZW20GT-20MG-STD) Screw: 20mm diameter, L / D20, full-flight screw Extrusion temperature: Feed unit / Compression unit / Measuring unit / Die = 150 / 200 / 220 / 230℃ • Polyolefin substrate layer (G) Extruder: Single-screw extruder (Plastics Engineering Laboratory Co., Ltd. GT-32-A) Screw: 32mm diameter, L / D 28, full-flight screw Extrusion temperature: Feeding section / Compression section / Measuring section / Die = 170 / 220 / 230 / 230℃ Die: 300mm wide, 3 types, 3-layer coat hanger die (manufactured by Plastics Engineering Laboratory Co., Ltd.) Die temperature: 230℃

[0078] The obtained multilayer film was stretched five times in the longitudinal direction and then five times in the transverse direction at 150°C using a tenter-type sequential biaxial stretching apparatus to obtain a biaxially oriented multilayer film with three layers of three types (vinyl alcohol copolymer layer (A) / polyolefin adhesive layer (H) / polyolefin substrate layer (G) = 2 μm / 2 μm / 20 μm).

[0079] On the surface of the vinyl alcohol copolymer layer (A) of the obtained biaxially oriented multilayer film, a silicon dioxide deposition layer (B) was formed using the following method with the winding-type vacuum deposition apparatus "EWA-105" manufactured by Nippon Vacuum Technology Co., Ltd., which has a transport chamber and a deposition chamber. The "EWA-105" has an unwinder and a winder on the transport chamber side, and silicon dioxide (SiO₂) is placed in the deposition chamber. XThe apparatus includes a crucible for heating the EVOH-1 and a cooling can for transporting and cooling the film, with the film being transported along the cooling can. The cooling can was cooled to -30°C, and a 20cm wide EVOH-1 film was transported at a transport speed of 150m / min. Furthermore, a nozzle was installed in the deposition chamber to directly blow oxygen onto the EVOH-1 before deposition (nozzle gap 2mm, film-nozzle distance 2cm, angle 30 degrees to the film), and vacuum deposition of silicon dioxide was performed while blowing oxygen at 0.38mL / min to produce a deposited film with a 40nm thick SiOx deposited layer (deposited layer (B)) formed on the EVOH-1. The thickness of the deposited layer (B) was adjusted by appropriately controlling the voltage applied to the crucible. A portion of the obtained deposited film was cut out and evaluated according to the method described in evaluation method (1) above. The results are shown in Table 1.

[0080] A two-component reactive polyurethane adhesive (24 parts by mass of "Takelac® A-520" and 4 parts by mass of "Takenate® A-50" manufactured by Mitsui Chemicals, Inc.) was mixed with 37 parts by mass of ethyl acetate to prepare an adhesive solution. The adhesive solution was applied to the vapor-deposited surface of the obtained vapor-deposited film using a wire bar so that the thickness after drying was 2 μm, and dried at 100°C for 5 minutes. This was then laminated to the corona-treated side of the CPP as a polyolefin layer (C), which is a sealant layer, to create a multilayer structure with layer thicknesses and layer configurations of polyolefin substrate layer (G) / polyolefin adhesive layer (H) / vinyl alcohol polymer layer (A) / vapor-deposited layer (B) / polyurethane adhesive layer / sealant layer = 20 μm / 2 μm / 2 μm / 40 nm / 2 μm / 50 μm. The bonding temperature (heating roll temperature) during lamination was 80°C, and after creating the multilayer structure, aging was performed at 40°C for 3 days. The obtained multilayer structures were evaluated according to the methods described in evaluation methods (2) to (4) above. The results are shown in Table 1.

[0081] [Examples 2-5, Comparative Example 1] Except for changing the transport speed of the biaxially oriented multilayer film during deposition to deposit silicon oxide deposition layers (B) with thicknesses of 60 nm (Example 2), 80 nm (Example 3), 100 nm (Example 4), 120 nm (Example 5), and 20 nm (Comparative Example 1), the deposited films and multilayer structures were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0082] Figure 1 shows a graph plotting the molar ratios of silicon (Si), oxygen (O), and carbon (C) (total 100 mol%) against sputtering time when a vapor-deposited layer (B) formed on a biaxially oriented ethylene-vinyl alcohol copolymer film (ethylene unit content 32 mol%, degree of saponification 99.9 mol%, thickness 12 μm) was analyzed using a scanning X-ray photoelectron spectroscopy analyzer under the same conditions as in Example 2. Figure 2 shows a graph plotting the molar ratio (O / Si) at that time against sputtering time. At the start of sputtering, carbon originating from organic contamination of the vapor-deposited film surface was detected on surface (b2), but after etching progressed for about 0.5 minutes, carbon was no longer detected. As etching progressed, carbon originating from the EVOH layer (A) of the substrate began to be detected, and at 6.01 minutes, when the carbon content reached 1 mol%, surface (b1) was reached, and the molar ratio of oxygen to silicon (O / Si) at this time was b1 Furthermore, at a sputtering time of 3.005 minutes, the molar ratio of oxygen (O) to silicon (Si) at positions equidistant from surfaces (b1) and (b2) was obtained. c The ratio [(O / Si) b1 / (O / Si) c The ratio was 1.17, indicating that the molar ratio (O / Si) was higher near the interface with the EVOH layer (A) compared to the center of the vapor-deposited layer (B).

[0083] [Example 6] Using the same materials and co-extrusion apparatus as in Example 1, three types of three-layer multilayer films (vinyl alcohol copolymer layer (A) / polyolefin adhesive layer (H) / polyolefin substrate layer (G) = 10 μm / 10 μm / 100 μm) were fabricated by adjusting the screw rotation speed and take-up roll speed. Subsequently, without stretching, vapor-deposited films and multilayer structures were prepared and evaluated in the same manner as in Example 4. The results are shown in Table 1.

[0084] [Example 7] Vapor-deposited films and multilayer structures were fabricated and evaluated using the same method as in Example 2, except that the oxygen supply rate during deposition was changed to 0.19 mL / min. The results are shown in Table 1.

[0085] [Example 8] A vapor-deposited film was prepared and evaluated using the same method as in Example 2, except that the oxygen supply rate during vapor deposition was changed to 0.78 mL / min. The results are shown in Table 1.

[0086] [Example 9] Using EVOH-2 as the material for the vinyl alcohol polymer layer (A), MAhPE1 as the material for the polyolefin adhesive layer (H), and PE1 as the material for the polyolefin substrate layer (G), a three-layer multilayer film (vinyl alcohol copolymer layer (A) / polyolefin adhesive layer (H) / polyolefin substrate layer (G) = thicknesses of 20 μm / 20 μm / 200 μm) was fabricated using a co-extrusion film manufacturing apparatus. The thickness of the multilayer film was adjusted by appropriately changing the screw rotation speed and the take-up roll speed. The extruder, extrusion conditions, and die used were as follows. • Vinyl alcohol-based polymer layer (A) Extruder: Single-screw extruder (Toyo Seiki Co., Ltd. Lab machine ME type CO-EXT) Screw: 20mm diameter, L / D20, full-flight screw Extrusion temperature: Feed unit / Compression unit / Measuring unit / Die = 175 / 220 / 220 / 220℃ • Polyolefin adhesive layer (H) Extruder: Single-screw extruder (Technovel Corporation SZW20GT-20MG-STD) Screw: 20mm diameter, L / D20, full-flight screw Extrusion temperature: Feed unit / Compression unit / Measuring unit / Die = 175 / 220 / 220 / 220℃ • Polyolefin substrate layer (G) Extruder: Single-screw extruder (Plastics Engineering Laboratory Co., Ltd. GT-32-A) Screw: 32mm diameter, L / D 28, full-flight screw Extrusion temperature: Feed unit / Compression unit / Measuring unit / Die = 175 / 220 / 230 / 220℃ Die: 300mm wide, 3 types, 3-layer coat hanger die (manufactured by Plastics Engineering Laboratory Co., Ltd.) Die temperature: 220℃

[0087] The obtained multilayer film was stretched five times in the longitudinal direction at 120°C using a uniaxial stretching machine to obtain a uniaxially oriented multilayer film consisting of three layers of three types (vinyl alcohol copolymer layer (A) / polyolefin adhesive layer (H) / polyolefin substrate layer (G) = 4 μm / 4 μm / 40 μm).

[0088] A vapor-deposited film was prepared by forming a 40 nm thick SiOx vapor-deposited layer (vapor-deposited layer (B)) on the surface of the vinyl alcohol copolymer layer (A) of the obtained biaxially oriented multilayer film on EVOH-2 in the same manner as in Example 1. A portion of the obtained vapor-deposited film was cut out and evaluated according to the method described in evaluation method (1) above. The results are shown in Table 1.

[0089] A two-component reactive polyurethane adhesive (24 parts by mass of "Takelac® A-520" and 4 parts by mass of "Takenate® A-50" manufactured by Mitsui Chemicals, Inc.) was mixed with 37 parts by mass of ethyl acetate to prepare an adhesive solution. The adhesive solution was applied to the vapor-deposited surface of the obtained vapor-deposited film using a wire bar so that the thickness after drying was 2 μm, and dried at 100°C for 5 minutes. This was then laminated to the corona-treated side of the LLDPE as a polyolefin layer (C), which is a sealant layer, to create a multilayer structure with layer thicknesses and layer configurations of polyolefin substrate layer (G) / polyolefin adhesive layer (H) / vinyl alcohol polymer layer (A) / vapor-deposited layer (B) / polyurethane adhesive layer / sealant layer = 40 μm / 4 μm / 4 μm / 40 nm / 2 μm / 50 μm. The bonding temperature (heating roll temperature) during lamination was 80°C, and after creating the multilayer structure, it was aged at 40°C for 3 days. The obtained multilayer structures were evaluated according to the methods described in evaluation methods (2) to (4) above. The results are shown in Table 1.

[0090] [Examples 10-13] Except for changing the transport speed of the biaxially oriented multilayer film during deposition to deposit silicon oxide deposition layers (B) with thicknesses of 60 nm (Example 10), 80 nm (Example 11), 100 nm (Example 12), and 120 nm (Example 13), the deposited films and multilayer structures were fabricated and evaluated in the same manner as in Example 9. The results are shown in Table 1.

[0091] [Example 14] Vapor-deposited films and multilayer structures were prepared and evaluated using the same method as in Example 10, except that the oxygen supply rate during deposition was changed to 0.19 mL / min. The results are shown in Table 1.

[0092] [Example 15] A vapor-deposited film was prepared in the same manner as in Example 1. A two-component reactive polyurethane adhesive (24 parts by mass of "Takelac® A-520" and 4 parts by mass of "Takenate® A-50" manufactured by Mitsui Chemicals, Inc.) was mixed with 37 parts by mass of ethyl acetate to prepare an adhesive solution. The adhesive solution was applied to the corona-treated surface of the BOPP (polyolefin layer (C)) using a wire bar so that the thickness after drying was 2 μm, dried at 100°C for 5 minutes, and laminated with the vapor-deposited side of the obtained vapor-deposited film. Next, the adhesive solution was applied to the corona-treated surface of the CPP as a polyolefin layer (C), which is a sealant layer, using a wire bar so that the thickness after drying was 2 μm. It was dried at 100°C for 5 minutes and laminated with the exposed side of the polyolefin substrate layer (G) of the multilayer structure after lamination with BOPP to produce a multilayer structure with thicknesses and layer configurations of BOPP layer / polyurethane adhesive layer / deposition layer (B) / vinyl alcohol polymer layer (A) / polyolefin adhesive layer (H) / polyolefin substrate layer (G) / polyurethane adhesive layer / sealant layer = 20 μm / 2 μm / 40 nm / 2 μm / 2 μm / 20 μm / 2 μm / 50 μm. The bonding temperature (heating roll temperature) during lamination was 80°C, and after producing the multilayer structure, aging was performed at 40°C for 3 days. The obtained multilayer structure was evaluated according to the methods described in evaluation methods (2) to (4) above. The results are shown in Table 1.

[0093] [Example 16] Silicon oxide in the deposition chamber is converted to aluminum oxide (AlO X Except for the change made to ), a vapor-deposited film was prepared in the same manner as in Example 2. A portion was cut out for vapor-deposited layer measurement. It was evaluated according to the method described in evaluation method (1) above. The results are shown in Table 1.

[0094] 10.4 g of tetraethoxysilane was mixed with 89.6 g of hydrochloric acid (0.1 N) and stirred for 30 minutes to hydrolyze and condense, obtaining a hydrolysis solution with a solid content of 3% by mass (in terms of SiO2). This solution was mixed with a 3% by mass aqueous solution of PVOH-1 in a mass ratio of 80 / 20 to prepare a coating solution for the protective layer. The obtained coating solution was applied to the AlOx surface of the alumina vapor-deposited layer of the vapor-deposited film obtained above using a wire bar so that the thickness after drying would be 2 μm, and the protective layer was formed by drying at 100°C for 5 minutes. In this way, a multilayer film with a layer structure and thickness of protective layer / vapor-deposited layer (B) / vinyl alcohol-based polymer layer (A) / polyolefin-based adhesive layer (H) / polyolefin substrate layer (G) = 2 μm / 60 nm / 2 μm / 2 μm / 20 μm was prepared. The obtained multilayer film was prepared and evaluated using the same method as in Example 1 for multilayer structures and products. The results are shown in Table 1.

[0095] [Comparative Example 2] Using PET (Comparative Example 2) instead of EVOH-1, MAhPP2 instead of MAhPP1, and PP1 as the material for the polyolefin substrate layer (G), a three-layer multilayer film (PET / polyolefin adhesive layer (H) / polyolefin substrate layer (G) = thickness of 50 μm / 50 μm / 500 μm) was manufactured using a co-extrusion apparatus. The thickness of the multilayer film was adjusted by appropriately changing the screw rotation speed and take-up roll speed. The extruder, extrusion conditions, and die used are as follows. PET Extruder: Single-screw extruder (Toyo Seiki Co., Ltd. Lab machine ME type CO-EXT) Screw: 20mm diameter, L / D20, full-flight screw Extrusion temperature: Feed unit / Compression unit / Measuring unit / Die = 260 / 260 / 260 / 260℃ • Polyolefin adhesive layer (H) Extruder: Single-screw extruder (Technovel Corporation SZW20GT-20MG-STD) Screw: 20mm diameter, L / D20, full-flight screw Extrusion temperature: Feed unit / Compression unit / Measuring unit / Die = 150 / 200 / 220 / 230℃ • Polyolefin substrate layer (G) Extruder: Single-screw extruder (Plastics Engineering Laboratory Co., Ltd. GT-32-A) Screw: 32mm diameter, L / D 28, full-flight screw Extrusion temperature: Feeding section / Compression section / Measuring section / Die = 170 / 220 / 230 / 230℃ Die: 300mm wide, 3 types, 3-layer coat hanger die (manufactured by Plastics Engineering Laboratory Co., Ltd.) Die temperature: 260℃

[0096] The obtained multilayer film was stretched five times in the longitudinal direction and then five times in the transverse direction at 150°C using a tenter-type sequential biaxial stretching machine to obtain a biaxially oriented multilayer film with three layers of three types (PET layer / polyolefin adhesive layer (H) / polyolefin substrate layer (G) = thickness of 2 μm / 2 μm / 20 μm).

[0097] A vapor-deposited film was prepared by forming a 60 nm thick SiOx vapor-deposited layer (vapor-deposited layer (B)) on the PET surface of the obtained biaxially oriented multilayer film in the same manner as in Example 2. A portion was cut out for vapor-deposited layer measurement. It was evaluated according to the method described in Evaluation Method (1) above. The results are shown in Table 1.

[0098] A two-component reactive polyurethane adhesive (24 parts by mass of "Takelac® A-520" and 4 parts by mass of "Takenate® A-50" manufactured by Mitsui Chemicals, Inc.) was mixed with 37 parts by mass of ethyl acetate to prepare an adhesive solution. The adhesive solution was applied to the vapor-deposited surface of the obtained vapor-deposited film using a wire bar so that the thickness after drying was 2 μm, and dried at 100°C for 5 minutes. This was then laminated to the corona-treated side of the CPP as a polyolefin layer (C), which serves as a sealant layer, to create a multilayer structure with a layer configuration of polyolefin substrate layer (G) / polyolefin adhesive layer (H) / PET layer / vapor-deposited layer (B) / polyurethane adhesive layer / sealant layer = 20 μm / 2 μm / 2 μm / 40 nm / 2 μm / 50 μm. The bonding temperature (heating roll temperature) during lamination was 80°C, and after creating the multilayer structure, it was aged at 40°C for 3 days. The obtained multilayer structures were evaluated according to the methods described in evaluation methods (2) to (4) above. The results are shown in Table 1.

[0099] [Comparative Example 3] Except for using PA instead of PET, vapor-deposited films and multilayer structures were fabricated and evaluated using the same method as in Comparative Example 2. The results are shown in Table 1.

[0100] [Comparative Example 4] Except for changing the oxygen supply rate during deposition to 0 mL / min, the vapor-deposited film and multilayer structure were prepared and evaluated using the same method as in Comparative Example 2. The results are shown in Table 1.

[0101] [Comparative Example 5] Except for changing the oxygen supply rate during deposition to 0 mL / min, the vapor-deposited film and multilayer structure were prepared and evaluated using the same method as in Example 2. The results are shown in Table 1.

[0102] Figure 3 shows a graph plotting the molar ratios of silicon, oxygen, and carbon (total 100 mol%) against sputtering time when a vapor-deposited layer (B) formed on a biaxially oriented ethylene-vinyl alcohol copolymer film (ethylene unit content 32 mol%, degree of saponification 99.9 mol%, thickness 12 μm) was analyzed using a scanning X-ray photoelectron spectroscopy analyzer under the same conditions as Comparative Example 5. Figure 4 shows a graph plotting the molar ratio (O / Si) at that time against sputtering time. At the start of sputtering, carbon originating from organic contamination of the vapor-deposited film surface was detected on surface (b2), but after etching progressed for about 0.5 minutes, carbon was no longer detected. As etching progressed, carbon originating from the EVOH layer (A) of the substrate began to be detected, and at 6.06 minutes, when the carbon content reached 1 mol%, surface (b1) was reached, and the molar ratio of oxygen to silicon at this time (O / Si) b1 Furthermore, at a sputtering time of 3.03 minutes, the molar ratio of oxygen (O) to silicon (Si) at positions equidistant from surfaces (b1) and (b2) was obtained. c The ratio [(O / Si) b1 / (O / Si) c The ratio was 1.08, indicating that the molar ratio (O / Si) near the interface with the EVOH layer (A) was smaller compared to Example 2, where oxygen was supplied during deposition.

[0103] [Comparative Example 6] Except for changing the oxygen supply rate during deposition to 0 mL / min, aluminum oxide vapor-deposited films and multilayer structures were prepared and evaluated using the same method as in Example 16. The results are shown in Table 1.

[0104] [Comparative Example 7] Aluminum oxide (AlO) in the vapor deposition chamber X Except for changing ) to aluminum (Al), vapor-deposited films and multilayer structures were fabricated and evaluated in the same manner as in Example 16. The results are shown in Table 1.

[0105] [Comparative Example 8] The vapor-deposited film was prepared and evaluated using the same method as in Example 2, except that the oxygen supply rate during vapor deposition was changed to 0.10 mL / min. The results are shown in Table 1.

[0106] [Comparative Example 9] Except for using PET instead of EVOH-1, a vapor-deposited film was prepared and evaluated in the same manner as in Example 16. The results are shown in Table 1.

[0107] [Comparative Example 10] A vapor-deposited film was prepared and evaluated in the same manner as in Example 16, except that PET was used instead of EVOH-1 and the oxygen supply rate during deposition was changed to 0 mL / min. The results are shown in Table 1.

[0108] [Table 1]

[0109] [Example 17] Six parts of ethylene-vinyl alcohol copolymer EVOH-3 and 92 parts of a mixed solvent (water / n-propanol = 8 / 2) were heated with stirring at 95°C for 1 hour, then the heating was stopped and stirring was continued until it returned to room temperature to obtain an aqueous PVOH-1 solution. A two-component reactive polyurethane adhesive (1.5 parts by mass of "Takelac (trademark) A-626" and 0.188 parts by mass of "Takenate (trademark) A-50" manufactured by Mitsui Chemicals, Inc.) was mixed with 32.5 parts by mass of ethyl acetate to prepare an anchor coat solution. BOPP was used as the polyolefin substrate layer (G), and the anchor coat solution was applied to the corona-treated surface of the BOPP using a wire bar so that the thickness after drying was 0.2 μm. The solution was dried at 100°C for 5 minutes to form an anchor coat layer. The EVOH-3 aqueous solution prepared above was applied to the anchor coat layer using a wire bar so that the thickness after drying was 0.5 μm, and then dried at 100°C for 5 minutes to form a barrier layer.

[0110] A vapor-deposited film was prepared by forming a 60 nm thick SiOx vapor-deposited layer (vapor-deposited layer (B)) on the EVOH surface of the obtained multilayer film in the same manner as in Example 2. A portion was cut out for vapor-deposited layer measurement. It was evaluated according to the method described in Evaluation Method (1) above. The results are shown in Table 2.

[0111] A two-component reactive polyurethane adhesive (24 parts by mass of "Takelac® A-520" and 4 parts by mass of "Takenate® A-50" manufactured by Mitsui Chemicals, Inc.) was mixed with 37 parts by mass of ethyl acetate to prepare an adhesive solution. The adhesive solution was applied to the vapor-deposited surface of the obtained vapor-deposited film using a wire bar so that the thickness after drying was 2 μm, and dried at 100°C for 5 minutes. This was then laminated to the corona-treated side of the CPP as a polyolefin layer (C), which is a sealant layer, to create a multilayer structure with layer thicknesses and layer configurations of polyolefin substrate layer (G) / polyurethane adhesive layer / vinyl alcohol polymer layer (A) / vapor-deposited layer (B) / polyurethane adhesive layer / sealant layer = 20 μm / 0.2 μm / 0.5 μm / 40 nm / 2 μm / 50 μm. The bonding temperature (heating roll temperature) during lamination was 80°C, and after creating the multilayer structure, it was aged at 40°C for 3 days. The obtained multilayer structures were evaluated according to the methods described in evaluation methods (2) to (4) above. The results are shown in Table 2.

[0112] [Examples 18, 19] Instead of EVOH-3, PVOH-1 (Example 18) and EVOH-2 (Example 19) were used as the material for the vinyl alcohol polymer layer (A), and vapor-deposited films and multilayer structures were fabricated and evaluated in the same manner as in Example 17. In Example 19, a mixed solvent (water / n-propanol = 35 / 65) was used. The results are shown in Table 2.

[0113] [Table 2]

[0114] [Example 20] The multilayer structure obtained in Example 1 was crushed to a size of 5 mm square or less. This crushed material was blended with polyethylene resin (Novatec® LD LJ400, manufactured by Nippon Polyethylene Co., Ltd.; low-density polyethylene, melting point 108°C) in a mass ratio (crushed material / polyethylene resin) of 40 / 60, and a single-layer film was produced under the extrusion conditions shown below to obtain a recovered composition film with a thickness of 50 μm. The film thickness was adjusted by appropriately changing the screw rotation speed and take-up roll speed. As a control, a polyethylene film with a thickness of 50 μm was obtained in the same manner using only polyethylene resin. Extruder: Single-screw extruder manufactured by Toyo Seiki Seisakusho Co., Ltd. Screw diameter: 20mmφ (L / D=20, Compression ratio=3.5, Full flight type) Extrusion temperature: C1 / C2 / C3 / D=160 / 190 / 190 / 190℃ Take-up roll temperature: 50℃ The extrudeability of the recovered composition was stable and good. Furthermore, the recovered composition film had almost the same amount of gel and material as the polyethylene film, and had a uniform and good appearance except for slight discoloration.

Claims

1. A multilayer structure comprising a vinyl alcohol-based polymer layer (A), a vapor-deposited film (X) containing a vapor-deposited layer (B) made of silicon dioxide or a metal oxide, and a polyolefin layer (C), wherein these layers are laminated together. A vapor-deposited layer (B) with a thickness of 30 nm to 200 nm is directly formed on the surface of a vinyl alcohol-based polymer layer (A). When elemental analysis of the deposited layer (B) is performed in the depth direction from surface (b2) to surface (b1) using a scanning X-ray photoelectron spectroscopy analyzer, with the side of the deposited layer (B) facing the vinyl alcohol polymer layer (A) designated as surface (b1) and the opposite side of the deposited layer (B) designated as surface (b2), the molar ratio (O / M) of oxygen element (O) to silicon element or metal element (M) on surface (b1) is determined. ｂ１ And the molar ratio (O / M) of oxygen element to silicon element or metal element (M) at positions equidistant from surfaces (b1) and (b2). ｃ The ratio [(O / M)] ｂ１ / (O / M) ｃ ] is between 1.1 and 1.7, The thickness of the vinyl alcohol polymer layer (A) is 0.1 μm or more and less than 20 μm, and A multilayer structure in which the ratio of the thickness of the layer mainly composed of polyolefin to the total thickness of the multilayer structure is 75% or more.

2. The multilayer structure according to claim 1, wherein the vapor-deposited layer (B) is made of silicon oxide or aluminum oxide.

3. The multilayer structure according to claim 2, wherein the vapor-deposited layer (B) is made of silicon dioxide.

4. The aforementioned molar ratio (O / M) ｂ１ The multilayer structure according to claim 1, wherein the ratio is 1.85 or more and 2.35 or less.

5. The aforementioned molar ratio (O / M) ｃ The multilayer structure according to claim 1, wherein the ratio is 1.5 or more and 2.0 or less.

6. The multilayer structure according to any one of claims 1 to 5, wherein the vapor-deposited film (X) comprises a polyolefin substrate layer (G), a polyolefin adhesive layer (H), a vinyl alcohol polymer layer (A), and a vapor-deposited layer (B) in this order.

7. The multilayer structure according to claim 6, comprising a polyolefin substrate layer (G), a polyolefin adhesive layer (H), and a vinyl alcohol polymer layer (A), which are co-extruded.

8. The multilayer structure according to claim 6, wherein a polyolefin substrate layer (G), a polyolefin adhesive layer (H), and a vinyl alcohol polymer layer (A) are stretched in at least one axial direction.

9. The multilayer structure according to claim 6, wherein the vinyl alcohol polymer layer (A) mainly comprises an ethylene-vinyl alcohol copolymer with an ethylene unit content of 10 to 65 mol% and a degree of saponification of 90 mol% or more.

10. The multilayer structure according to any one of claims 1 to 5, wherein the vapor-deposited film (X) has a polyolefin substrate layer (G), a vinyl alcohol-based polymer layer (A), and a vapor-deposited layer (B) in this order.

11. The multilayer structure according to claim 10, wherein a vinyl alcohol-based polymer layer (A) is formed by coating a polyolefin substrate layer (G) with a vinyl alcohol-based polymer solution or dispersion.

12. The multilayer structure according to claim 10, wherein the vinyl alcohol polymer layer (A) mainly comprises a vinyl alcohol polymer with an ethylene unit content of 50 mol% or less and a degree of saponification of 70 mol% or more.

13. A multilayer structure according to any one of claims 1 to 5, having a plurality of polyolefin layers (C), one of which is an unstretched polyolefin layer and the other is a stretched polyolefin layer.

14. A multilayer structure according to any one of claims 1 to 5, which does not contain a layer mainly composed of a resin with a melting point of 200°C or higher, or a metal layer with a thickness of 1 μm or more.

15. A packaging material comprising a multilayer structure according to any one of claims 1 to 5.

16. A package comprising contents contained in the packaging material described in claim 15, A packaging body in which the contents contain 5% by mass or more of water, and at least one selected from the group consisting of 1% by mass or more of lipids, 1% by mass or more of sodium chloride, and 0.5% by mass or more of acetic acid.

17. A recovery composition comprising a recovered multilayer structure according to any one of claims 1 to 5.

18. A method for recovering a multilayer structure, comprising crushing the multilayer structure according to any one of claims 1 to 5 and then melt-molding it.

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